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1.
Langmuir ; 40(16): 8418-8426, 2024 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-38588383

RESUMEN

Degradation of dyes under natural light sources is one of the most active research areas in basic science for greener technology. In this context, the photocatalytic activity of semiconductors has received massive attention in solving water treatment-related issues as these possess enormous potential for degrading organic impurities. Here, we report that barium aluminate (BaAl2O4, BAO), which has been extensively studied for photoluminescence applications, is found to be a highly potent candidate for photocatalytic activities. We have explored the degradation of dyes (meant for water purification) by using the photocatalytic properties of pure and Dy- and Yb-codoped BAO. Crystal structure, electron microscopy, and Raman analysis of the autocombustion-synthesized pure and codoped BAO samples revealed significant morphological changes such as increased particle size and stabilization of rod-like structures. UV-vis absorbance measurements confirm the presence of multiple bandgaps in the BAO samples, which is substantiated by X-ray absorption spectroscopy measurements. Photocatalytic degradation studies of methylene blue (MB) dye (with different catalyst concentrations, dopings, and MB dye concentrations) have been carried out by using BAO. The kinetics of the photocatalytic degradation measurements has been explained by the Boltzmann distribution function, and the fastest (in less than 40 min), with more than 99% degradation of MB impurity, is reported here for the first time in BAO compounds. Synthesized BAO samples show excellent cyclic stability, which is essential for their potential applications in environmental remediation. The trade-off between the enhancement of surface area and increased particle size is considered the key parameter for controlling the photocatalytic performance of the BAO catalyst after Dy and Yb codopings.

2.
Nanotechnology ; 35(27)2024 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-38635294

RESUMEN

The tuning of exchange bias (EB) in nanoparticles has garnered significant attention due to its diverse range of applications. Here, we demonstrate EB in single-phase CoO nanoparticles, where two magnetic phases naturally emerge as the crystallite size decreases from 34.6 ± 0.8 to 10.8 ± 0.9 nm. The Néel temperature (TN) associated with antiferromagnetic ordering decreases monotonically with the reduction in crystallite size, highlighting the significant influence of size effects. The 34.6 nm nanoparticles exhibit magnetization irreversibility between zero-field cooled (ZFC) and field-cooled (FC) states belowTN. With further reduction in size this irreversibility appears well aboveTN, resulting in the absence of true paramagnetic regime which indicates the occurnace of an additional magnetic phase. The frequency-dependent ac-susceptibility in 10.8 nm nanoparticles suggests slow dynamics of disordered surface spins aboveTN, coinciding with the establishment of long-range order in the core. The thermoremanent magnetization (TRM) and iso-thermoremanent magnetization (IRM) curves suggest a core-shell structure: the core is antiferromagnetic, and the shell consists of disordered surface spins causing ferromagnetic interaction. Hence, the EB in these CoO nanoparticles results from the exchange coupling between an antiferromagnetic core and a disordered shell that exhibits unconventional surface spin characteristics.

3.
Proc Natl Acad Sci U S A ; 113(47): 13504-13509, 2016 11 22.
Artículo en Inglés | MEDLINE | ID: mdl-27834215

RESUMEN

Schizophrenia, a devastating psychiatric illness with onset in the late teens to early 20s, is thought to involve disrupted brain connectivity. Functional and structural disconnections of cortical networks may underlie various cognitive deficits, including a substantial reduction in the speed of information processing in schizophrenia patients compared with controls. Myelinated white matter supports the speed of electrical signal transmission in the brain. To examine possible neuroanatomical sources of cognitive deficits, we used a comprehensive diffusion-weighted imaging (DWI) protocol and characterized the white matter diffusion signals using diffusion kurtosis imaging (DKI) and permeability-diffusivity imaging (PDI) in patients (n = 74), their nonill siblings (n = 41), and healthy controls (n = 113). Diffusion parameters that showed significant patient-control differences also explained the patient-control differences in processing speed. This association was also found for the nonill siblings of the patients. The association was specific to processing-speed abnormality but not specific to working memory abnormality or psychiatric symptoms. Our findings show that advanced diffusion MRI in white matter may capture microstructural connectivity patterns and mechanisms that govern the association between a core neurocognitive measure-processing speed-and neurobiological deficits in schizophrenia that are detectable with in vivo brain scans. These non-Gaussian diffusion white matter metrics are promising surrogate imaging markers for modeling cognitive deficits and perhaps, guiding treatment development in schizophrenia.


Asunto(s)
Imagen de Difusión Tensora , Procesos Mentales/fisiología , Esquizofrenia/fisiopatología , Adolescente , Adulto , Anisotropía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Análisis de Regresión , Sustancia Blanca/fisiopatología , Adulto Joven
4.
Hum Brain Mapp ; 39(12): 4893-4902, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-30052318

RESUMEN

We measured and compared heritability estimates for measures of functional brain connectivity extracted using the Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) rsfMRI analysis pipeline in two cohorts: the genetics of brain structure (GOBS) cohort and the HCP (the Human Connectome Project) cohort. These two cohorts were assessed using conventional (GOBS) and advanced (HCP) rsfMRI protocols, offering a test case for harmonization of rsfMRI phenotypes, and to determine measures that show consistent heritability for in-depth genome-wide analysis. The GOBS cohort consisted of 334 Mexican-American individuals (124M/210F, average age = 47.9 ± 13.2 years) from 29 extended pedigrees (average family size = 9 people; range 5-32). The GOBS rsfMRI data was collected using a 7.5-min acquisition sequence (spatial resolution = 1.72 × 1.72 × 3 mm3 ). The HCP cohort consisted of 518 twins and family members (240M/278F; average age = 28.7 ± 3.7 years). rsfMRI data was collected using 28.8-min sequence (spatial resolution = 2 × 2 × 2 mm3 ). We used the single-modality ENIGMA rsfMRI preprocessing pipeline to estimate heritability values for measures from eight major functional networks, using (1) seed-based connectivity and (2) dual regression approaches. We observed significant heritability (h2 = 0.2-0.4, p < .05) for functional connections from seven networks across both cohorts, with a significant positive correlation between heritability estimates across two cohorts. The similarity in heritability estimates for resting state connectivity measurements suggests that the additive genetic contribution to functional connectivity is robustly detectable across populations and imaging acquisition parameters. The overarching genetic influence, and means to consistently detect it, provides an opportunity to define a common genetic search space for future gene discovery studies.


Asunto(s)
Corteza Cerebral/fisiología , Conectoma/métodos , Herencia/fisiología , Imagen por Resonancia Magnética/métodos , Red Nerviosa/fisiología , Fenotipo , Adulto , Corteza Cerebral/diagnóstico por imagen , Estudios de Cohortes , Familia , Femenino , Humanos , Masculino , Americanos Mexicanos , Persona de Mediana Edad , Red Nerviosa/diagnóstico por imagen , Gemelos , Adulto Joven
5.
Psychosom Med ; 79(7): 770-776, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28498274

RESUMEN

OBJECTIVE: The fornix is a white matter tract carrying the fibers connecting the hippocampus and the hypothalamus, two essential stress-regulatory structures of the brain. We tested the hypothesis that allostatic load (AL), derived from a battery of peripheral biomarkers indexing the cumulative effects of stress, is associated with abnormalities in brain white matter microstructure, especially the fornix, and that higher AL may help explain the white matter abnormalities in schizophrenia. METHODS: Using 13 predefined biomarkers, we tested AL in 44 schizophrenic patients and 33 healthy controls. Diffusion tensor imaging was used to obtain fractional anisotropy (FA) values of the fornix and other white matter tracts. RESULTS: AL scores were significantly elevated in patients compared with controls (F(3,77) = 7.87, p = .006). AL was significantly and inversely correlated with FA of fornix in both controls (r = -.58, p = .001) and patients (r = -.36, p = .023). Several nominally significant (p < .05 but did not survive Bonferroni correction for multiple comparison) correlations were also observed between AL and FA of other white matter tracts in schizophrenic patients. However, the fornix was the only tract exhibiting a correlation with AL in both groups. CONCLUSIONS: These results provide initial evidence that allostatic processes are linked to fornix microstructure in clinical participants.


Asunto(s)
Alostasis/fisiología , Imagen de Difusión Tensora/métodos , Fórnix/patología , Esquizofrenia , Estrés Psicológico , Adulto , Biomarcadores , Femenino , Fórnix/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Esquizofrenia/metabolismo , Esquizofrenia/patología , Esquizofrenia/fisiopatología , Estrés Psicológico/metabolismo , Estrés Psicológico/fisiopatología
6.
Hum Brain Mapp ; 37(2): 525-35, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26538488

RESUMEN

INTRODUCTION: Diffusion weighted imaging (DWI) methods can noninvasively ascertain cerebral microstructure by examining pattern and directions of water diffusion in the brain. We calculated heritability for DWI parameters in cerebral white (WM) and gray matter (GM) to study the genetic contribution to the diffusion signals across tissue boundaries. METHODS: Using Old Order Amish (OOA) population isolate with large family pedigrees and high environmental homogeneity, we compared the heritability of measures derived from three representative DWI methods targeting the corpus callosum WM and cingulate gyrus GM: diffusion tensor imaging (DTI), the permeability-diffusivity (PD) model, and the neurite orientation dispersion and density imaging (NODDI) model. These successively more complex models represent the diffusion signal modeling using one, two, and three diffusion compartments, respectively. RESULTS: We replicated the high heritability of the DTI-based fractional anisotropy (h(2) = 0.67) and radial diffusivity (h(2) = 0.72) in WM. High heritability in both WM and GM tissues were observed for the permeability-diffusivity index from the PD model (h(2) = 0.64 and 0.84), and the neurite density from the NODDI model (h(2) = 0.70 and 0.55). The orientation dispersion index from the NODDI model was only significantly heritable in GM (h(2) = 0.68). CONCLUSION: DWI measures from multicompartmental models were significantly heritable in WM and GM. DWI can offer valuable phenotypes for genetic research; and genes thus identified may reveal mechanisms contributing to mental and neurological disorders in which diffusion imaging anomalies are consistently found. Hum Brain Mapp 37:525-535, 2016. © 2015 Wiley Periodicals, Inc.


Asunto(s)
Cuerpo Calloso/anatomía & histología , Imagen de Difusión Tensora , Carácter Cuantitativo Heredable , Sustancia Blanca/anatomía & histología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Amish , Imagen de Difusión Tensora/métodos , Femenino , Sustancia Gris/anatomía & histología , Giro del Cíngulo/anatomía & histología , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Masculino , Persona de Mediana Edad , Modelos Neurológicos , Fenotipo , Adulto Joven
7.
Hum Brain Mapp ; 37(12): 4673-4688, 2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-27477775

RESUMEN

BACKGROUND: Altered brain connectivity is implicated in the development and clinical burden of schizophrenia. Relative to matched controls, schizophrenia patients show (1) a global and regional reduction in the integrity of the brain's white matter (WM), assessed using diffusion tensor imaging (DTI) fractional anisotropy (FA), and (2) accelerated age-related decline in FA values. In the largest mega-analysis to date, we tested if differences in the trajectories of WM tract development influenced patient-control differences in FA. We also assessed if specific tracts showed exacerbated decline with aging. METHODS: Three cohorts of schizophrenia patients (total n = 177) and controls (total n = 249; age = 18-61 years) were ascertained with three 3T Siemens MRI scanners. Whole-brain and regional FA values were extracted using ENIGMA-DTI protocols. Statistics were evaluated using mega- and meta-analyses to detect effects of diagnosis and age-by-diagnosis interactions. RESULTS: In mega-analysis of whole-brain averaged FA, schizophrenia patients had lower FA (P = 10-11 ) and faster age-related decline in FA (P = 0.02) compared with controls. Tract-specific heterochronicity measures, that is, abnormal rates of adolescent maturation and aging explained approximately 50% of the regional variance effects of diagnosis and age-by-diagnosis interaction in patients. Interactive, three-dimensional visualization of the results is available at www.enigma-viewer.org. CONCLUSION: WM tracts that mature later in life appeared more sensitive to the pathophysiology of schizophrenia and were more susceptible to faster age-related decline in FA values. Hum Brain Mapp 37:4673-4688, 2016. © 2016 Wiley Periodicals, Inc.


Asunto(s)
Envejecimiento/patología , Encéfalo/diagnóstico por imagen , Encéfalo/crecimiento & desarrollo , Esquizofrenia/diagnóstico por imagen , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/crecimiento & desarrollo , Adolescente , Adulto , Estudios de Cohortes , Imagen de Difusión Tensora , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Adulto Joven
8.
Brain ; 136(Pt 6): 1942-55, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23739917

RESUMEN

The thalamus plays crucial roles in the development and mature functioning of numerous sensorimotor, cognitive and attentional circuits. Currently limited evidence suggests that autism spectrum disorder may be associated with thalamic abnormalities, potentially related to sociocommunicative and other impairments in this disorder. We used functional connectivity magnetic resonance imaging and diffusion tensor imaging probabilistic tractography to study the functional and anatomical integrity of thalamo-cortical connectivity in children and adolescents with autism spectrum disorder and matched typically developing children. For connectivity with five cortical seeds (prefontal, parieto-occipital, motor, somatosensory and temporal), we found evidence of both anatomical and functional underconnectivity. The only exception was functional connectivity with the temporal lobe, which was increased in the autism spectrum disorders group, especially in the right hemisphere. However, this effect was robust only in partial correlation analyses (partialling out time series from other cortical seeds), whereas findings from total correlation analyses suggest that temporo-thalamic overconnectivity in the autism group was only relative to the underconnectivity found for other cortical seeds. We also found evidence of microstructural compromise within the thalamic motor parcel, associated with compromise in tracts between thalamus and motor cortex, suggesting that the thalamus may play a role in motor abnormalities reported in previous autism studies. More generally, a number of correlations of diffusion tensor imaging and functional connectivity magnetic resonance imaging measures with diagnostic and neuropsychological scores indicate involvement of abnormal thalamocortical connectivity in sociocommunicative and cognitive impairments in autism spectrum disorder.


Asunto(s)
Corteza Cerebral/patología , Corteza Cerebral/fisiología , Trastornos Generalizados del Desarrollo Infantil/patología , Tálamo/patología , Tálamo/fisiología , Adolescente , Niño , Trastornos Generalizados del Desarrollo Infantil/metabolismo , Trastornos Generalizados del Desarrollo Infantil/psicología , Estudios de Cohortes , Imagen de Difusión Tensora/métodos , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Vías Nerviosas/patología , Vías Nerviosas/fisiología
9.
ACS Appl Mater Interfaces ; 16(26): 33752-33762, 2024 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-38902888

RESUMEN

The sensitivity of ferroelectric domain walls to external stimuli makes them functional entities in nanoelectronic devices. Specifically, optically driven domain reconfiguration with in-plane polarization is advantageous and thus is highly sought. Here, we show the existence of in-plane polarized subdomains imitating a single domain state and reversible optical control of its domain wall movement in a single-crystal of ferroelectric BaTiO3. Similar optical control in the domain configuration of nonpolar ferroelastic material indicates that long-range ferroelectric polarization is not essential for the optical control of domain wall movement. Instead, flexoelectricity is found to be an essential ingredient for the optical control of the domain configuration, and hence, ferroelastic materials would be another possible candidate for nanoelectronic device applications.

10.
Cereb Cortex ; 21(10): 2233-43, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21378114

RESUMEN

Growing consensus suggests that autism spectrum disorders (ASD) are associated with atypical brain networks, thus shifting the focus to the study of connectivity. Many functional connectivity studies have reported underconnectivity in ASD, but results in others have been divergent. We conducted a survey of 32 functional connectivity magnetic resonance imaging studies of ASD for numerous methodological variables to distinguish studies supporting general underconnectivity (GU) from those not consistent with this hypothesis (NGU). Distinguishing patterns were apparent for several data analysis choices. The study types differed significantly with respect to low-pass filtering, task regression, and whole-brain field of view. GU studies were more likely to examine task-driven time series in regions of interest, without the use of low-pass filtering. Conversely, NGU studies mostly applied task regression (for removal of activation effects) and low-pass filtering, testing for correlations across the whole brain. Results thus suggest that underconnectivity findings may be contingent on specific methodological choices. Whereas underconnectivity reflects reduced efficiency of within-network communication in ASD, diffusely increased functional connectivity can be attributed to impaired experience-driven mechanisms (e.g., synaptic pruning). Both GU and NGU findings reflect important aspects of network dysfunction associated with sociocommunicative, cognitive, and sensorimotor impairments in ASD.


Asunto(s)
Trastornos Generalizados del Desarrollo Infantil/diagnóstico , Trastornos Generalizados del Desarrollo Infantil/fisiopatología , Imagen por Resonancia Magnética , Red Nerviosa/fisiopatología , Niño , Humanos , Imagen por Resonancia Magnética/métodos , Imagen por Resonancia Magnética/normas
11.
J Child Psychol Psychiatry ; 52(3): 286-95, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21073464

RESUMEN

BACKGROUND: Previous diffusion tensor imaging (DTI) studies have shown white matter compromise in children and adults with autism spectrum disorder (ASD), which may relate to reduced connectivity and impaired function of distributed networks. However, tract-specific evidence remains limited in ASD. We applied tract-based spatial statistics (TBSS) for an unbiased whole-brain quantitative estimation of the fractional anisotropy (FA), mean diffusion (MD) and axial and radial diffusion of the white matter tracts in children and adolescents with ASD. METHODS: DTI was performed in 26 ASD and 24 typically developing (TD) participants, aged 9-20 years. Groups were matched for age and IQ. Each participant's aligned FA, MD and axial and radial diffusion data were projected onto the mean FA skeleton representing the centers of all tracts and the resulting data fed into voxelwise group statistics. RESULTS: TBSS revealed decreased FA and increased MD and radial diffusion in the ASD group compared to the TD group in the corpus callosum, anterior and posterior limbs of the internal capsule, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, superior longitudinal fasciculus, cingulum, anterior thalamic radiation, and corticospinal tract. No single site with inverse effects (increased FA, reduced MD or radial diffusion in the ASD group) was detected. In clusters of significant group difference, age was positively correlated with FA and negatively correlated with MD and radial diffusion in the TD, but not the ASD group. CONCLUSIONS: Our findings reveal white matter compromise affecting numerous tracts in children and adolescents with ASD. Slightly varying patterns of diffusion abnormalities detected for some tracts may suggest tract-specific patterns of white matter abnormalities associated with ASD. Age-dependent effects further show that maturational changes (increasing FA, decreasing MD and radial diffusion with age) are diminished in ASD from school-age childhood into young adulthood.


Asunto(s)
Encéfalo/patología , Trastornos Generalizados del Desarrollo Infantil/patología , Adolescente , Factores de Edad , Anisotropía , Estudios de Casos y Controles , Niño , Cuerpo Calloso/patología , Imagen de Difusión Tensora , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Tractos Piramidales/patología , Población Blanca , Adulto Joven
12.
Appl Opt ; 50(34): 6319-26, 2011 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-22192982

RESUMEN

Absorption of CW Yb-fiber laser light of 1.07 µm wavelength in water has been measured at different water temperatures and laser intensities. The absorption coefficient was estimated to be 0.135 cm(-1) at 25 °C water temperature, and this was found to decrease with temperature at a rate of 5.7 × 10(-4) cm(-1) °C(-1). The absorption coefficient increased significantly when the laser beam was focused in water, and the increase depended on the distance of the focal point from the water surface. This has been attributed to the absorption and scattering losses of laser radiation in a cavity formed in water by the focused beam at laser intensities in the megawatts per square centimeter and higher range.

13.
Acta Neurochir (Wien) ; 151(9): 1037-51, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19572103

RESUMEN

PURPOSE: Tentorial meningiomas, comprising approximately 3-6% of all intracranial meningiomas, are complex entities with an intricate relationship to surrounding structures and require multiple surgical approaches. In the present study, the rationale for deciding the approaches for TMs and the perioperative management dilemmas were evaluated. METHODS: Thirty-seven patients (28 primary [supratentorial (2), infratentorial (20) and both (6)] and nine complex [cerebellopontine (CP) angle (5) and petroclival (4)] underwent surgery using the occipital transtentorial, supracerebellar infratentorial, subtemporal transtentorial, bioccipital suboccipital, midline suboccipital, retrosigmoid, and combined pre and retrosigmoid approaches. The extent of excision was categorized according to Simpson's grade. RESULTS: Simpson's grade of excision was I in six, II in 11, III in nine and IV in 11 patients, respectively. Follow-up assessment (2 months to 9 years) in 27 patients (72.9%) showed that 23 patients returned to their previous activity level with either no or minimal symptoms, three returned to previous activity level with major cranial nerve palsy, and one patient required permanent assistance. One patient had recurrence and four others underwent resurgery for residual tumor. Two patients with petroclival lesions died due to aspiration pneumonitis and meningitis, respectively; one with CP angle TM presented in a poor general condition and expired following emergency ventriculoperitoneal shunt and subsequent definite surgery. Pseudomeningocele, cerebrospinal fluid leak, and cranial nerve palsy were the major morbidities. CONCLUSIONS: Classifying TM into medial and lateral, supra and infratentorial groups helps in deciding an appropriate and safe approach. Meticulously preserving venous sinuses is important since the risk of venous infarction cannot be predicted even with radiological good venous collaterization and apparent venous sinus blockade by tumor. Laterally situated tumors carry a better prognosis when compared to the medially situated ones. Leaving a small residual tumor in an effort to preserve important neurovascular structures does not obviate the expectation of a good long-term prognosis with minimal morbidity and low recurrence rates.


Asunto(s)
Duramadre/cirugía , Neoplasias Meníngeas/cirugía , Meningioma/cirugía , Complicaciones Posoperatorias/etiología , Adolescente , Adulto , Infarto Encefálico/prevención & control , Tronco Encefálico/irrigación sanguínea , Tronco Encefálico/patología , Tronco Encefálico/cirugía , Cerebelo/irrigación sanguínea , Cerebelo/patología , Cerebelo/cirugía , Niño , Preescolar , Fosa Craneal Posterior/diagnóstico por imagen , Fosa Craneal Posterior/patología , Fosa Craneal Posterior/cirugía , Senos Craneales/anatomía & histología , Senos Craneales/cirugía , Descompresión Quirúrgica/métodos , Duramadre/patología , Femenino , Humanos , Masculino , Neoplasias Meníngeas/diagnóstico por imagen , Neoplasias Meníngeas/patología , Meningioma/diagnóstico por imagen , Meningioma/patología , Persona de Mediana Edad , Recurrencia Local de Neoplasia/epidemiología , Procedimientos Neuroquirúrgicos/métodos , Complicaciones Posoperatorias/mortalidad , Complicaciones Posoperatorias/prevención & control , Estudios Prospectivos , Radiografía , Adulto Joven
14.
Pediatr Neurosurg ; 45(1): 37-45, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19221461

RESUMEN

AIM: Spontaneous intracranial hemorrhage (SICH) in children is relatively less common as compared to adults, and there are limited studies addressing this issue in children. In this study, we analyze the etiology, clinical features, treatment options and outcome assessment in this population. MATERIAL AND METHODS: Fifty consecutive patients of spontaneous intracerebral bleed, aged 18 years and below, were retrospectively analyzed based on medical records and radiographic images. Status of the patient at the final follow-up after discharge was considered as the outcome. RESULTS: Age of patients ranged from 2 months to 17 years with higher predilection in males (M:F = 3:2). Presenting features were symptoms of raised intracranial pressure (70.0%), deterioration in sensorium (50.0%), limb weakness (36.0%) and seizures (28%). Arteriovenous malformation (AVM) was the most common cause of hemorrhage, and was found in 22 patients (44%), followed by cerebral aneurysm in 17 cases (34%), moyamoya disease in 3 cases (6%), and intracranial tumor, hematological disorders and unknown cause (possible vasculitis) were each found in 2 patients (4%). Treatment modalities consisted of: excision of AVM, aneurysm clipping, embolization, superficial temporal artery to middle cerebral artery bypass, tumor excision, hematoma evacuation and conservative management. Thirty-five patients (74%) had good outcome and 13 patients had poor outcome (26%). CONCLUSIONS: Aneurysm is an important cause of SICH, alongside AVM, which is the leading cause. Thorough investigation is necessary to elucidate the cause of bleed, which may otherwise be missed. Cerebellar bleed and late presentation were found to be associated with poor outcome. Age was not found to be associated with outcome.


Asunto(s)
Aneurisma Intracraneal/complicaciones , Malformaciones Arteriovenosas Intracraneales/complicaciones , Hemorragias Intracraneales/etiología , Enfermedad de Moyamoya/complicaciones , Adolescente , Edad de Inicio , Niño , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Lactante , Aneurisma Intracraneal/diagnóstico por imagen , Aneurisma Intracraneal/cirugía , Malformaciones Arteriovenosas Intracraneales/diagnóstico por imagen , Malformaciones Arteriovenosas Intracraneales/cirugía , Hemorragias Intracraneales/diagnóstico por imagen , Hemorragias Intracraneales/cirugía , Masculino , Enfermedad de Moyamoya/diagnóstico por imagen , Enfermedad de Moyamoya/cirugía , Procedimientos Neuroquirúrgicos , Estudios Retrospectivos , Tomografía Computarizada por Rayos X
15.
Schizophr Bull ; 45(3): 647-658, 2019 04 25.
Artículo en Inglés | MEDLINE | ID: mdl-29912445

RESUMEN

BACKGROUND: The underlying neurobiological mechanism for abnormal functional connectivity in schizophrenia (SCZ) remains unknown. This project investigated whether glutamate and GABA, 2 metabolites that contribute to excitatory and inhibitory functions, may influence functional connectivity in SCZ. METHODS: Resting-state functional magnetic resonance imaging and proton magnetic resonance spectroscopy were acquired from 58 SCZ patients and 61 healthy controls (HC). Seed-based connectivity maps were extracted between the anterior cingulate cortex (ACC) spectroscopic voxel and all other brain voxels. Magnetic resonance spectroscopy (MRS) spectra were processed to quantify glutamate and GABA levels. Regression analysis was performed to describe relationships between functional connectivity and glutamate and GABA levels. RESULTS: Reduced ACC functional connectivity in SCZ was found in regions associated with several neural networks including the default mode network (DMN) compared to HC. In the HC, positive correlations were found between glutamate and both ACC-right inferior frontal gyrus functional connectivity and ACC-bilateral superior temporal gyrus functional connectivity. A negative correlation between GABA and ACC-left posterior cingulate functional connectivity was also observed in HC. These same relationships were not statistically significant in SCZ. CONCLUSIONS: The present investigation is one of the first studies to examine links between functional connectivity and glutamate and GABA levels in SCZ. Results indicate that glutamate and GABA play an important role in the functional connectivity modulation in the healthy brain. The absence of glutamate and GABA correlations in areas where SCZ showed significantly reduced functional connectivity may suggest that this chemical-functional relationship is disrupted in SCZ.


Asunto(s)
Conectoma , Ácido Glutámico/metabolismo , Giro del Cíngulo , Red Nerviosa , Corteza Prefrontal , Esquizofrenia , Lóbulo Temporal , Ácido gamma-Aminobutírico/metabolismo , Adulto , Femenino , Giro del Cíngulo/diagnóstico por imagen , Giro del Cíngulo/metabolismo , Giro del Cíngulo/fisiopatología , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Red Nerviosa/diagnóstico por imagen , Red Nerviosa/metabolismo , Red Nerviosa/fisiopatología , Corteza Prefrontal/diagnóstico por imagen , Corteza Prefrontal/metabolismo , Corteza Prefrontal/fisiopatología , Espectroscopía de Protones por Resonancia Magnética , Esquizofrenia/diagnóstico por imagen , Esquizofrenia/metabolismo , Esquizofrenia/fisiopatología , Lóbulo Temporal/diagnóstico por imagen , Lóbulo Temporal/metabolismo , Lóbulo Temporal/fisiopatología , Adulto Joven
16.
Schizophr Bull ; 45(5): 1051-1059, 2019 09 11.
Artículo en Inglés | MEDLINE | ID: mdl-30576563

RESUMEN

Negative symptoms represent a distinct component of psychopathology in schizophrenia (SCZ) and are a stable construct over time. Although impaired frontostriatal connectivity has been frequently described in SCZ, its link with negative symptoms has not been carefully studied. We tested the hypothesis that frontostriatal connectivity at rest may be associated with the severity of negative symptoms in SCZ. Resting state functional connectivity (rsFC) data from 95 mostly medicated patients with SCZ and 139 healthy controls (HCs) were acquired. Negative symptoms were assessed using the Brief Negative Symptom Scale. The study analyzed voxel-wise rsFC between 9 frontal "seed regions" and the entire striatum, with the intention to reduce potential biases introduced by predefining any single frontal or striatal region. SCZ showed significantly reduced rsFC between the striatum and the right medial and lateral orbitofrontal cortex (OFC), lateral prefrontal cortex, and rostral anterior cingulate cortex compared with HCs. Further, rsFC between the striatum and the right medial OFC was significantly associated with negative symptom severity. The involved striatal regions were primarily at the ventral putamen. Our results support reduced frontostriatal functional connectivity in SCZ and implicate striatal connectivity with the right medial OFC in negative symptoms. This task-independent resting functional magnetic resonance imaging study showed that medial OFC-striatum functional connectivity is reduced in SCZ and associated with severity of negative symptoms. This finding supports a significant association between frontostriatal connectivity and negative symptoms and thus may provide a potential circuitry-level biomarker to study the neurobiological mechanisms of negative symptoms.


Asunto(s)
Cuerpo Estriado/diagnóstico por imagen , Giro del Cíngulo/diagnóstico por imagen , Corteza Prefrontal/diagnóstico por imagen , Esquizofrenia/diagnóstico por imagen , Adolescente , Adulto , Anciano , Estudios de Casos y Controles , Niño , Cuerpo Estriado/fisiopatología , Femenino , Lóbulo Frontal/diagnóstico por imagen , Lóbulo Frontal/fisiopatología , Neuroimagen Funcional , Giro del Cíngulo/fisiopatología , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Vías Nerviosas , Corteza Prefrontal/fisiopatología , Putamen/diagnóstico por imagen , Putamen/fisiopatología , Descanso , Esquizofrenia/fisiopatología , Adulto Joven
17.
Brain Imaging Behav ; 13(5): 1453-1467, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30191514

RESUMEN

Large-scale consortium efforts such as Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) and other collaborative efforts show that combining statistical data from multiple independent studies can boost statistical power and achieve more accurate estimates of effect sizes, contributing to more reliable and reproducible research. A meta- analysis would pool effects from studies conducted in a similar manner, yet to date, no such harmonized protocol exists for resting state fMRI (rsfMRI) data. Here, we propose an initial pipeline for multi-site rsfMRI analysis to allow research groups around the world to analyze scans in a harmonized way, and to perform coordinated statistical tests. The challenge lies in the fact that resting state fMRI measurements collected by researchers over the last decade vary widely, with variable quality and differing spatial or temporal signal-to-noise ratio (tSNR). An effective harmonization must provide optimal measures for all quality data. Here we used rsfMRI data from twenty-two independent studies with approximately fifty corresponding T1-weighted and rsfMRI datasets each, to (A) review and aggregate the state of existing rsfMRI data, (B) demonstrate utility of principal component analysis (PCA)-based denoising and (C) develop a deformable ENIGMA EPI template based on the representative anatomy that incorporates spatial distortion patterns from various protocols and populations.


Asunto(s)
Mapeo Encefálico/métodos , Encéfalo/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética/métodos , Adulto , Anciano , Artefactos , Femenino , Neuroimagen Funcional , Humanos , Masculino , Persona de Mediana Edad , Relación Señal-Ruido , Adulto Joven
18.
Acta Neurochir (Wien) ; 150(9): 865-77; discussion 877, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18754074

RESUMEN

BACKGROUND: Surgical management of giant medial sphenoid meningiomas (> or =5 cm in maximum dimension) is extremely challenging due to their intimate relationship with vital neural structures like the optic nerve, cranial nerves of the cavernous sinus and the cavernous internal carotid artery. Their surgical management is presented incorporating a radiological scoring system that predicts the grade of tumour excision. MATERIALS AND METHODS: 20 patients of giant medial sphenoidal wing meningioma (maximum tumour dimension range: 5.2 to 9.5 cm; mean maximum dimension = 6.12 +/- 1.06 cm) with mainly visual and extraocular movement deficits, and raised intracranial pressure, underwent surgery. A preoperative radiological scoring system (range 1-12) was proposed considering tumour volume (using Kawamoto's method); extension into the surrounding surgical corridors; extent of cavernous sinus invasion (based on the tumour relationship to the cavernous internal carotid artery); associated hyperostosis and/or >50% calcification; and, associated brain oedema. Both the conventional frontotemporal craniotomy (n = 13) and its extension to orbitozygomatic osteotomy (n = 7) were utilized. The cavernous sinus was explored in 4 patients and the hyperostotic sphenoid ridge drilled in five patients. FINDINGS: Total excision was achieved in nine patients; small tumour remnants within the cavernous sinus, interpeduncular fossa or suprasellar cistern were left in eight patients; and less than 10% of tumour was left in three patients. A patient with a completely calcified meningioma died due to myocardial infarction. When the preoperative radiological score was > or =7, there was considerable difficulty in achieving total tumour excision. A mean follow of 17.58 +/- 15.05 months revealed improvement in visual acuity/field defects in three, stabilisation in 11, and deterioration of ipsilateral visual acuity in five patients. Symptoms of raised pressure, cognitive dysfunction, aphasia and proptosis showed improvement. CONCLUSION: A relatively conservative approach to these extensive lesions resulted in good outcome in a majority of our patients. Both the standard as well as skull base approaches may be utilized for successful removal of giant medial sphenoidal wing meningiomas. A preoperative radiological score of > or =7 predicts a greater degree of difficulty in achieving complete surgical extirpation.


Asunto(s)
Imagen por Resonancia Magnética , Neoplasias Meníngeas/diagnóstico , Meningioma/diagnóstico , Procedimientos Neuroquirúrgicos/métodos , Índice de Severidad de la Enfermedad , Tomografía Computarizada por Rayos X , Adulto , Anciano , Edema Encefálico/diagnóstico por imagen , Edema Encefálico/etiología , Calcinosis/diagnóstico por imagen , Seno Cavernoso/diagnóstico por imagen , Seno Cavernoso/patología , Femenino , Estudios de Seguimiento , Humanos , Hiperostosis/diagnóstico por imagen , Hiperostosis/etiología , Masculino , Neoplasias Meníngeas/complicaciones , Neoplasias Meníngeas/cirugía , Meningioma/complicaciones , Meningioma/cirugía , Persona de Mediana Edad , Invasividad Neoplásica , Valor Predictivo de las Pruebas , Hueso Esfenoides/diagnóstico por imagen , Resultado del Tratamiento
19.
Ostomy Wound Manage ; 54(5): 43-9, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18493093

RESUMEN

Quality of life is a subjectively interpreted phenomenon that can be profoundly altered by the presence of a wound. Particularly when complete and expedient healing seems unrealistic, quality of life becomes the focus of care. To assess the influence of a variety of chronic wounds on patient quality of life, a 1-day, descriptive study was conducted among 50 consecutive outpatients (64% men, 36% women; age range 14 to 78 years) with chronic wounds who attended the Wound Clinic of the University Hospital, Varanasi, India. A quality-of-life questionnaire containing six parameters (physical activities, feelings, household duties, leisure time activities, social relations, and general activities) was developed and administered. Demographic information was available as a result of a previous study at this institution. Quality-of-life scores were grouped as satisfactory and unsatisfactory and participants were grouped by age (<30 years old, 30 to 60 years old, >60 years old). Wounds were classified by cause (diabetes, venous disease, pressure ulcer, and tuberculosis) and size (<10 cm2, 10 to 50 cm2, >50 cm2). The most common site was the lower limb or foot (39, 78%), followed by upper limb (six, 12%) and head, neck, and trunk (five, 10%). More than half (28, 56%) of all patients had an unsatisfactory overall quality-of-life score. The percentage of patients with satisfactory scores was higher in patients with smaller versus larger wounds and wounds located on upper rather than lower limbs, as well as in middle-aged versus younger or older patients. This patient-centered instrument helped document important quality-of-life concerns among chronic wound patients.


Asunto(s)
Calidad de Vida , Heridas y Lesiones/fisiopatología , Adolescente , Adulto , Anciano , Enfermedad Crónica , Femenino , Humanos , Masculino , Persona de Mediana Edad , Encuestas y Cuestionarios , Heridas y Lesiones/enfermería , Heridas y Lesiones/psicología
20.
J Wound Ostomy Continence Nurs ; 35(4): 407-11, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18635991

RESUMEN

AIM: To identify patients at risk for developing pressure ulcer among hospitalized patients and the prevalence of pressure ulcer in this group. PATIENTS AND METHOD: A prospective study included 100 patients from medical and surgical wards. Data were collected on admission, and subjects were followed up at regular intervals. The Waterlow pressure ulcer risk assessment tool was completed and patients were stratified "as not at risk," "at risk", "high risk", and "very high risk". Subjects were then monitored for 2 weeks and the actual incidence of pressure ulcer formation was analyzed in the various risk groups. RESULTS: Of 100 patients studied, 20% were at risk, 10% were assessed at high risk, and 7% were classified as at very high risk for developing a pressure ulcer. Necessary preventive measures were taken (posture change, specialized beds/mattresses, nursing care, nutritional input, etc) for those patients at risk of development of pressure ulcer. Four of 7 patients (57.1%) who were at very high-risk developed pressure ulcer as compared with 2 of 10 patients (20%) categorized in the high-risk category within a period of 2 weeks. No patient who was classified as not at risk on the Waterlow pressure ulcer risk assessment tool developed a pressure ulcer within the observation period. CONCLUSION: Pressure ulcers developed in identified risk groups despite adequate available preventive measure being taken to prevent their development. It is of extreme importance to identify patients at risk for the development of pressure ulcers so that preventive measures can be instituted to reduce the incidence of hospital-acquired pressure ulcers.


Asunto(s)
Pacientes Internos/estadística & datos numéricos , Úlcera por Presión/epidemiología , Medición de Riesgo , Humanos , Incidencia , Postura , Úlcera por Presión/prevención & control , Prevalencia , Estudios Prospectivos
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