Diffuse Spectra Research Articles

Phenotypic and epigenetic heterogeneity in FGFR2-fused glial and glioneuronal tumours.

FGFR-fused central nervous system (CNS) tumours are rare and are usually within the glioneuronal and neuronal tumours or the paediatric-type diffuse low-grade glioma spectrum. Among this spectrum, FGFR2 fusion has been documented in tumours classified by DNA-methylation profiling as polymorphous low-grade neuroepithelial tumours of the young (PLNTY), a recently described tumour type. However, FGFR2 fusions have also been reported in glioneuronal tumours, highlighting the overlapping diagnostic criteria and challenges. We investigated the FGFR2 fusion landscape in a French national series of tumours sent to the RENOCLIP-LOC network. We comprehensively analysed histology, radiology and molecular data including DNA-methylation profiling for 16 FGFR2-fused glioneuronal tumours. Most tumours were located in the temporal or parietal lobe with a median age at diagnosis of 7years [1-44]. Epilepsy was the most frequent symptom. Five patients had tumour progression or recurrence with a median progression-free survival of 22.6months. Histological phenotypes corresponding to PLNTY, GG, MVNT or unclassified tumours were recorded. Epigenetic profiling could not properly distinguish epigenetic clusters related to the GG and PLNTY methylation classes among FGFR2-fused glioneuronal tumours. However, a neuroradiological review identified strikingly distinct neuroradiological patterns. While delineating tumour types among the FGFR2-fused glioneuronal tumour spectrum, by histopathology or DNA-methylation profiling, remains challenging, neuroimaging data revealed two distinct patterns that could correlate to PLNTY and ganglioglioma. However, more series including extensive histo-radio-molecular data are needed to confirm this hypothesis.

The synthesis, structures and characterizations of (C5H12NO)4Cd3Cl10·2H2O and (C5H12NO)2BiCl6·H5O2 crystals

Two new organic-inorganic hybrid crystals (C5H12NO)4Cd3Cl10·2H2O and (C5H12NO)2BiCl6·H5O2 were synthesized by solution method, and their basic physical properties, including structures, thermal stability analysis, UV–Vis diffuse reflectance absorption spectra and photoluminescent characteristic were characterized. The two crystals both crystallize in same monoclinic crystal system, but different P21/c and C2/c space group for (C5H12NO)4Cd3Cl10·2H2O and (C5H12NO)2BiCl6·H5O2, respectively. Their infrared, Raman and mass spectrometry were measured, with related characteristic peaks were identified. The Raman peaks at 249 and 88 cm−1 are ascribed to Cd-Cl stretching vibration and Cl-Cd-Cl deformation vibration, respectively. The mass spectra analysis confirm the existence of C5H12NO+ cation, [CdCl]+ and Na-(C5H12NO)2BiCl6·H4O2. A phase transition peak that respectively located at 378 and 403 K for (C5H12NO)4Cd3Cl10·2H2O and (C5H12NO)2BiCl6·H5O2 was detected by the synchronous thermal analysis, which is related with the loss of crystalline water in their structures. In addition, the maximum absorption peak at 230 and 240 nm, with corresponding band gap of 3.35 and 3.15 eV were fitted for (C5H12NO)4Cd3Cl10·2H2O and (C5H12NO)2BiCl6·H5O2, respectively. Furthermore, (C5H12NO)4Cd3Cl10·2H2O features a bluish white emission with the peak centering at 496 nm when it was excited at 380 nm by a Xenon lamp. This work extends the catalog of organic-inorganic hybrid metal halides and presents the potential application of (C5H12NO)4Cd3Cl10·2H2O in optical field.

Differentiation between high-grade gliomas and solitary brain metastases based on multidiffusion MRI model quantitative analysis.

Differentiating high-grade gliomas (HGGs) from solitary brain metastases (SBMs) using conventional magnetic resonance imaging (MRI) remains challenging due to their similar imaging features. This study aimed to evaluate the diagnostic performance of advanced diffusion models, such as neurite orientation dispersion and density imaging (NODDI) and mean apparent propagator magnetic resonance imaging (MAP-MRI), incomparison to traditional techniques like diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), and diffusion kurtosis imaging (DKI) for distinguishing HGGs from SBMs. In total, 17 patients with HGGs and 26 patients with SBMs were prospectively recruited based on the established inclusion and exclusion criteria. Structural MRI sequences and diffusion spectrum imaging (DSI) were utilized to assess quantitative parameter models, including NODDI, MAP-MRI, DWI, DTI, and DKI. Quantitative parameters were measured for both the tumor parenchymal area and the peritumoral edema area. The quantitative parameters of the two patient groups were compared using either the independent Student's t-test or the Mann-Whitney U test. The effectiveness of each model was evaluated using receiver operating characteristic (ROC) curves and calculating the area under the curve (AUC). Finally, the DeLong test was employed to compare the diagnostic performance of each model through pairwise comparisons of ROC curves. Isotropic volume fraction (Viso) based on NODDI; mean squared displacement (MSD) and the return to plane probabilities (RTPP) based on MAP-MRI; radial diffusivity (RDk) and mean diffusivity (MDk) based on DKI; and axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD) based on DTI of the peritumoral edema tumor were significantly different between HGGs and SBMs (p < 0.05). The optimal single discriminant parameters for each model are NODDI_Viso, MAP-MRI_MSD, DKI_MDk, and DTI_AD. Among these, the AUC of Viso (0.809) exceeds that of MSD (0.733), MDk (0.718), and AD (0.779). The combined model, which incorporates DTI_AD, DKI_RD, and NODDI_Viso, demonstrated superior diagnostic performance (0.897). Advanced diffusion MRI quantitative parameters derived from NODDI, such as Viso, have the potential to enhance the differentiation between HGGs and SBMs. The integrated utilization of these models is anticipated to enhance diagnostic accuracy and refine MRI protocols for brain tumor assessment.

Assessing Visual Pathway White Matter Degeneration in Primary Open‐Angle Glaucoma Using Multiple MRI Morphology and Diffusion Metrics

BackgroundPrimary open‐angle glaucoma (POAG), a leading cause of irreversible blindness, is associated with neurodegeneration in the visual pathway, but the underlying pathophysiology remains incompletely resolved.PurposeTo characterize macro‐ and microstructural white matter abnormalities in optic tract (OT) and optic radiation (OR) of POAG.Study typeProspective.PopulationsA total of 34 POAG patients (21 males, 13 females) and 25 healthy controls (HCs) (16 males, nine females).Field Strength/Sequence3 T; multiband spin‐echo echo planar diffusion spectrum imaging (DSI).AssessmentWe compared multiple morphology metrics, including volume, area, length, and shape metrics, as well as diffusion metrics such as diffusion tensor imaging (fractional anisotropy [FA], mean diffusivity, radial diffusivity, and axial diffusivity), mean apparent propagator (mean squared displacement, q‐space inverse variance, return‐to‐origin probability, return‐to‐axis probabilities [RTAP] and return‐to‐plane probabilities, non‐Gaussianity, perpendicular non‐Gaussianity, parallel non‐Gaussianity), and neurite orientation dispersion and density imaging (intracellular volume fraction, orientation dispersion index [ODI], and isotropic volume fraction of the OT and OR).Statistical TestsStatistical comparisons and classifications employed linear mixed model and logistic regression. Diagnostic performance was assessed using area under the receiver operating characteristic curve (AUC). P‐value &lt;0.05 was statistically significant.ResultsMorphology analysis in POAG revealed a lower span in the OR (29.43 ± 2.30 vs. 30.59 ± 2.01, 3.8%) and OT (19.73 ± 2.21 vs. 20.68 ± 1.37, 4.6%), and a higher curl (3.03 ± 0.22 vs. 2.90 ± 0.16, 4.5%) in OT. Diffusion metrics revealed lower mean FA (OR: 0.328 ± 0.03 vs. 0.340 ± 0.018, 3.5%; OT: 0.255 ± 0.022 vs. 0.268 ± 0.018, 4.9%) and lower mean RTAP (OR: 5.919 ± 0.529 vs. 6.216 ± 0.489, 4.8%; OT: 4.089 ± 0.402 vs. 4.280 ± 0.353, 4.5%), with higher mean ODI in the OT (0.448 ± 0.029 vs. 0.433 ± 0.025, 3.5%). Combined models, incorporating these MRI metrics, effectively discriminated POAG from HCs, achieving AUCs of 0.84 for OR and 0.83 for OT.Data ConclusionsDSI‐derived morphology and diffusion metrics demonstrated macro‐ and micro abnormalities in the visual pathway, providing insights into POAG‐related neurodegeneration.Level of Evidence2Technical EfficacyStage 3

Triggered Directed Electron Redistribution Endowed by Efficient Ohmic Contacts of NiMoN/Ni3S2 for Boosting Large Current‐Density Overall Seawater Splitting

AbstractThe rational construction of interfacial nanostructures of metal/semiconductor (MS) contacted electrocatalysts has a significant impact on improving their intrinsic activities. However, MS contacts are often plagued by a strong Fermi‐level pinning effect, resulting in the formation of the Schottky barrier that affects the adsorption of hydrogen/oxygen intermediates. Herein, an Ohmic contact between metallic Ni3S2 and semiconducting NiMoN is well‐designed, which effectively reduces the electron conduction barriers. The as‐obtained NiMoN/Ni3S2 has remarkable bifunctional water electrolysis performance. At 10 mA·cm−2, the overpotential of hydrogen evolution and oxygen evolution reaction is 70 and 154 mV, respectively. Impressively, the formation of hydroxide during surface reconstruction can avoid the chlorine evolution on the catalyst surface. At an industrial process temperature of 85 °C, it takes only 340 mV for the overall seawater splitting of 500 mA·cm−2. UPS and UV‐VIS diffuse spectra combined with theoretical calculation results confirm that the self‐driven directed electron transfer derived from the Ohmic contact can induce local electron enrichment at the interface region, thus promoting the formation of *O to *OOH. This study provides important insights into the coordinated modulation of built‐in electric fields and the preparation of efficient multifunctional catalysts with a high abundance of active sites.

Application of CoLD-CoP to Detecting Competitively and Cooperatively Binding Ligands.

NMR utilization in fragment-based drug discovery requires techniques to detect weakly binding fragments and to subsequently identify cooperatively binding fragments. Such cooperatively binding fragments can then be optimized or linked in order to develop viable drug candidates. Similarly, ligands or substrates that bind macromolecules (including enzymes) in competition with the endogenous ligand or substrate are valuable probes of macromolecular chemistry and function. The lengthy and costly process of identifying competitive or cooperative binding can be streamlined by coupling computational biochemistry and spectroscopy tools. The Clustering of Ligand Diffusion Coefficient Pairs (CoLD-CoP) method, previously developed by Snyder and co-workers, detects weakly binding ligands by analyzing pairs of diffusion spectra, obtained in the absence and the presence of a protein. We extended the CoLD-CoP method to analyze spectra pairs (each in the presence of a protein) with or without a critical ligand, to detect both competitive and cooperative binding.

Berezinsky hidden sources: an emergent tension in the high-energy neutrino sky?

The IceCube Collaboration has recently reported compelling evidence of high-energy neutrino emission from NGC 1068, and also mild excesses for NGC 4151 and CGCG420-015, local Seyfert galaxies. This has increased the interest along neutrino emission from hot-corona surrounding the super massive black holes of Seyfert Galaxies. In this paper, we revisit phenomenological constraints on the neutrino emission from hot-coronae of Seyfert galaxies, using an assumption of sub-equipartition between cosmic-rays and magnetic energy densities. We show that not only these sources are consistent with such an assumption but also that the data point towards low values for the ratio between thermal and magnetic pressure, the so called beta plasma parameters inside Seyfert galaxies. We exploit this finding to constrain the Seyfert diffuse neutrino flux and we obtain that, in order not to overproduce neutrinos, not all the sources can be efficient neutrino emitters. In our approach (along with previous findings), Seyfert galaxies provide a negligible contribution to the diffuse neutrino spectrum above ∼ 100 TeV, allowing space for other astrophysical sources. However, future data from high-energy neutrino telescopes will be crucial to shed more light onto the contribution of this source class to the cosmic neutrino background.

Nonparametric distributions of tensor-valued Lorentzian diffusion spectra for model-free data inversion in multidimensional diffusion MRI.

Magnetic resonance imaging (MRI) is the method of choice for noninvasive studies of micrometer-scale structures in biological tissues via their effects on the time- and frequency-dependent (restricted) and anisotropic self-diffusion of water. While new designs of time-dependent magnetic field gradient waveforms have enabled disambiguation between different aspects of translational motion that are convolved in traditional MRI methods relying on single pairs of field gradient pulses, data analysis for complex heterogeneous materials remains a challenge. Here, we propose and demonstrate nonparametric distributions of tensor-valued Lorentzian diffusion spectra, or "D(ω) distributions," as a general representation with sufficient flexibility to describe the MRI signal response from a wide range of model systems and biological tissues investigated with modulated gradient waveforms separating and correlating the effects of restricted and anisotropic diffusion.

Exploring the effect of thin film thicknesses on linear and nonlinear optical properties of MoO3 thin film

The structural, morphological, linear, and nonlinear optical properties of MoO3 thin films deposited by thermal deposition were measured. The effect of various thicknesses of films was studied. The structural and morphological parameters of films, determined by x-ray diffraction, field emission scanning electron microscopy, and AFM images, are compared to the linear and nonlinear optical characteristics of these media. The bandgap of the prepared thin films was obtained from the diffuse reflectance spectroscopy spectra. The electron’s effective mass (me*/m0), linear refractive index (n0), and optical static and high frequency dielectric constant (ɛ0, ɛ∞) values were calculated by using the bandgap energy values. Increasing the thicknesses of thin films decreased the bandgap, increased the root mean square, and increased the size of nanoparticles and the nonlinear response of thin films. The high magnitude of n2 and β was because of MoO3 (300 nm-thickness), which were of the order of 10−5 cm2/W and 10−1 cm/W, respectively. The fluctuations in nonlinear responses observed at different thicknesses are attributed to d–d transitions and intraband scattering of equilibrium electrons influenced by laser radiation, as indicated by the nonlinearity data. The considerably elevated refractive nonlinearity values in the analyzed film materials suggest their potential for practical application in optoelectronic devices.

Diffusion spectrum imaging in patients with idiopathic normal pressure hydrocephalus: correlation with ventricular enlargement

BackgroundTo investigate the association between white matter changes and ventricular expansion in idiopathic normal pressure hydrocephalus (iNPH) based on diffusion spectrum imaging (DSI).MethodsWe included 32 patients with iNPH who underwent DSI using a 3T MRI scanner. The lateral ventricles were manually segmented, and ventricular volumes were measured. Two methods were utilised in the study: manual region-of-interest (ROI) delineation and tract diffusion profile analysis. General fractional anisotropy (GFA) and fractional anisotropy (FA) were extracted in different white matter regions, including the bilateral internal capsule (anterior and posterior limbs) and corpus callosum (body, genu, and splenium) with manual ROI delineation. The 18 main tracts in the brain of each patient were extracted; the diffusion metrics of 100 equidistant nodes on each fibre were calculated, and Spearman’s correlation coefficient was used to determine the correlation between diffusion measures and ventricular volume of iNPH patients.ResultsThe GFA and FA of all ROI showed no significant correlation with lateral ventricular volume. However, in the tract diffusion profile analysis, lateral ventricular volume was positively correlated with part of the cingulum bundle, left corticospinal tract, and bilateral thalamic radiation posterior, whereas it was negatively correlated with the bilateral cingulum parahippocampal (all p < 0.05).ConclusionsThe effect of ventricular enlargement in iNPH on some white matter fibre tracts around the ventricles was limited and polarizing, and most white matter fibre tract integrity changes were not associated with ventricular enlargement; this reflects that multiple pathological mechanisms may have been combined to cause white matter alterations in iNPH.

Improvement of O/W emulsion stability and rheological properties by highly branched cyclic dextrin and preparation of a novel emulsion gel

The objective of this study was to formulate and investigate a low-oil emulsion gel (20%, v/v) stabilized by highly branched cyclic dextrin (HBCD). The results indicated that HBCD effectively prevented the coalescence of oil droplets when the concentration reached a specific threshold (40 wt%). All samples exhibited dense network structure and elastic solid properties when stored at 4 °C. Fluorescence images showed the oil droplets tended to be irregular after refrigeration, indicating HBCD molecules aggregated under low temperature. Fourier transform infrared spectroscopy and its deconvolution results displayed a shift in the hydroxyl peak and an increase in R1046/1022. Additionally, new crystalline peaks emerged at 17° and 22° in the X-ray diffusion spectra of recrystallized HBCD samples. It suggested the hydrogen bonds and ordered structure of HBCD were increased in the emulsion gels during storage. Therefore, the formation and orderly arrangement of double helix structures of the branched chains which stabilized by hydrogen bonds promoted the recrystallization and self-assembly of HBCD, ultimately resulting in the formation of a stable gel structure. The research provided theoretical feasibility for the development of structured emulsions for functional foods.

In-situ sonochemical formation of N-graphyne modulated porous g-C3N4 for boosted photocatalysis degradation of pollutants and nitrogen fixation

Herein, Nitrogen-doped graphyne/porous g-C3N4 composites are firstly in-situ synthesized via the ultrasound vibration of CaC2, triazine, and porous g-C3N4 in absolute ethanol. A variety of characterizations are performed to investigate the morphology, microstructure, composition, and electrical/optical features of the obtained composites, such as transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectra, X-ray photoelectron spectroscopy, and so forth. It is found that N-doped graphyne with flexible folds lamellar structure is intimately attached to flake g-C3N4 in the as-prepared composites. An enlargement of 1.68 and 1.44 folds for the photocatalytic degradation of levofloxacin, rhodamine B, Methylene blue, and Tetracycline is realized by N-doped graphyne/g-C3N4 in comparison with that of pristine g-C3N4, respectively. In addition, the highest NH3 production rate attains 1.71 mmol⋅gcat−1⋅h−1 for N-doped graphyne/g-C3N4, which is 5.89 times larger than that of g-C3N4 (0.29 mmol⋅gcat−1⋅h−1). The improved mechanism of photocatalysis including higher photo-response and carrier separation rate is verified by transient photo-current, transient photo-potential, Mott-Schottky plots, Tafel plots, electrochemical impedance spectroscopy, turn-over frequency, photoluminescence spectra, and UV–vis diffuse absorption spectra, etc. Overall, the current study shows that N-doped graphyne synthesized from CaC2 and triazine is a useful decoration to modulate the photocatalytic features of g-C3N4, which can also be widely extended for in-situ modification of other photocatalysts.

Clinical characteristics of post-stroke basal ganglia aphasia and the study of language-related white matter tracts based on diffusion spectrum imaging

BackgroundStroke often damages the basal ganglia, leading to atypical and transient aphasia, indicating that post-stroke basal ganglia aphasia (PSBGA) may be related to different anatomical structural damage and functional remodeling rehabilitation mechanisms. The basal ganglia contain dense white matter tracts (WMTs). Hence, damage to the functional tract may be an essential anatomical structural basis for the development of PSBGA. MethodsWe first analyzed the clinical characteristics of PSBGA in 28 patients and 15 healthy controls (HCs) using the Western Aphasia Battery and neuropsychological test batteries. Moreover, we investigated white matter injury during the acute stage using diffusion magnetic resonance imaging scans for differential tractography. Finally, we used multiple regression models in correlation tractography to analyze the relationship between various language functions and quantitative anisotropy (QA) of WMTs. ResultsCompared with HCs, patients with PSBGA showed lower scores for fluency, comprehension (auditory word recognition and sequential commands), naming (object naming and word fluency), reading comprehension of sentences, Mini-Mental State Examination, and Montreal Cognitive Assessment, along with increased scores in Hamilton Anxiety Scale-17 and Hamilton Depression Scale-17 within 7 days after stroke onset (P < 0.05). Differential tractography revealed that patients with PSBGA had damaged fibers, including in the body fibers of the corpus callosum, left cingulum bundles, left parietal aslant tracts, bilateral superior longitudinal fasciculus II, bilateral thalamic radiation tracts, left fornix, corpus callosum tapetum, and forceps major, compared with HCs (FDR < 0.02). Correlation tractography highlighted that better comprehension was correlated with a higher QA of the left inferior fronto-occipital fasciculus (IFOF), corpus callosum forceps minor, and left extreme capsule (FDR < 0.0083). Naming was positively associated with the QA of the left IFOF, forceps minor, left arcuate fasciculus, and uncinate fasciculus (UF) (FDR < 0.0083). Word fluency of naming was also positively associated with the QA of the forceps minor, left IFOF, and thalamic radiation tracts (FDR < 0.0083). Furthermore, reading was positively correlated with the QA of the forceps minor, left IFOF, and UF (FDR < 0.0083). ConclusionPSBGA is primarily characterized by significantly impaired word fluency of naming and preserved repetition abilities, as well as emotional and cognitive dysfunction. Damaged limbic pathways, dorsally located tracts in the left hemisphere, and left basal ganglia pathways are involved in PSBGA pathogenesis. The results of connectometry analysis further refine the current functional localization model of higher-order neural networks associated with language functions.

Benzoselenadiazole-Functionalized H-Bonded Arylamide Foldamers: Solvent-Responsive Properties and Helix Self-Assembly Directed by Chalcogen Bonding in Solid State.

In this study, a series of H-bonded arylamide foldamers bearing benzoselenadiazole ends with solvent-responsive properties have been synthesized. In dichloromethane or dimethyl sulfoxide solvents, the molecules exhibit meniscus or linear structures, respectively, which can be attributed to the unique intramolecular hydrogen bonding behavior evidenced by 1D 1H NMR and 2D NOESY spectra. UV-vis spectroscopy experiments show that the absorption wavelength of H-bonded arylamide foldamers are significantly red-shifted due to the presence of benzoselenadiazole group. In addition, the crystal structures reveal that effective intermolecular dual Se ⋅ ⋅ ⋅ N interactions between benzoselenadiazole groups induce further assembly of the monomers. Remarkably, supramolecular linear and double helices structures are constructed under the synergistic induction of intramolecular hydrogen bonding and intermolecular chalcogen bonding. Additionally, 2D DOSY diffusion spectra and theoretical modelling based on density functional theory (DFT) are performed to explore the persistence of intermolecular Se ⋅ ⋅ ⋅ N interactions beyond the crystalline state.

Structural changes in corticospinal tract profiling via multishell diffusion models and their relation to overall survival in glioblastoma

PurposeAdvanced MR fiber tracking imaging reflects fiber bundle invasion by glioblastoma, particularly of the corticospinal tract (CST), which is more susceptible as the largest downstream fiber tracts. We aimed to investigate whether CST features can predict the overall survival of glioblastoma. MethodsIn this prospective secondary analysis, 40 participants (mean age, 58 years; 16 male) pathologically diagnosed with glioblastoma were enrolled. Diffusion spectrum MRI was used for CST reconstruction. Fifty morphological and diffusion indicators (DTI, DKI, NODDI, MAP and Q-space) were used to characterize the CST. Optimal parameters capturing fiber bundle damage were obtained through various grouping methods. Eventually, the correlation with overall survival was determined by the hazard ratios (HRs) from various Cox proportional hazard model combinations. ResultsOnly intracellular volume fraction (ICVF) and non-Gaussianity (NG) values on the affected tumor level were significant in all four groups or stratified comparisons (all P < .05). During the median follow-up 698 days, only the ICVF on the affected tumor level was independently associated with overall survival, even after adjusting for all classic prognostic factors (HR [95 % CI]: 0.611 [0.403, 0.927], P = .021). Moreover, stratification by the ICVF on the affected tumor level successfully predicted risk (P < .01) and improved the C-index of the multivariate model (from 0.695 to 0.736). ConclusionsThis study demonstrates a relationship between NODDI-derived CST features, ICVF on the affected tumor level, and overall survival in glioblastoma. Independent of classical prognostic factors for glioblastoma, a lower ICVF on the affected tumor level might predict a lower overall survival.

Deciphering non-Gaussianity of diffusion based on the evolution of diffusivity

Non-Gaussian diffusion of nanoparticles in complex media disrupts Einstein's picture of Brownian motion, and non-Gaussianity is thought to be closely related to diffusing diffusivity generated by spatiotemporal heterogeneities. However, the correlation between non-Gaussianity and the dynamics of heterogeneous environments in anomalous diffusion remains uncertain. Inspired by a recent study by Alexandre [], we demonstrate that non-Gaussianity can be deciphered through the spatiotemporal evolution of heterogeneity-dependent diffusivity distribution. Using diffusion experiments in a linear temperature field and Brownian dynamics simulations, we found that short-time non-Gaussianity can be predicted based on the boundary ratio of the diffusivity distribution; the long-time non-Gaussianity either approaches an asymptotic value of −2 or scales with 1/t, depending on the dominance of particle migration. The temporal variation of non-Gaussianity is determined by an effective Péclet number, which represents a competition between the varying rate of diffusivity and the diffusivity of diffusivity and reveals whether the tail distribution expands or contracts. The tail is more Gaussian than exponential over long times, with exceptions significantly dependent on the diffusivity distribution. Our findings provide a versatile framework for understanding non-Gaussian diffusion in probability space, and shed light on establishing a diffusion spectrum in cells and characterizing nanomedicine transport in biological microenvironment using non-Gaussian statistics. Published by the American Physical Society 2024

Application of Corn Straw, an Agro-Waste, to Remove Dyes in an Aqueous Medium, Producing Blue or Red Fibers

The contaminant dyes that, even at low concentrations, may cause a series of adverse effects in humans and animals, and their removal by adsorption methods using alternative adsorbents as natural fibers, are regarded as a research topic that has become increasingly relevant. In this study, corn straw (CS), an agro-industrial residue, was used to remove dyes. The samples were characterized by ATR-FTIR, SEM-EDS, zeta potential, diffuse spectra, and colorimetry, before and after dye removal. The analyses allowed us to differentiate the morphology of CS after the treatment’s fiber on the adsorbent surface. The zeta potential showed a negative surface charge, but the acidic or alkaline treatment affected the surface charge of the sample, influencing the adsorption of cationic or anionic dyes. Adsorption data presented an increased removal when alkaline treatment was applied for the methylene blue (MB; qmax = 16.7 mg g−1), and the acid treatment was more effective for the Congo red (CR; qmax = 2.13 mg g−1). After color stability tests, it was observed that the anionic dye CR was more easily desorbed due to the surface charge of the adsorbent. Due to the chemical treatment, corn straw proved to be a good sustainable adsorbent for removing anionic or cationic dyes from aqueous media, contributing directly to the objective of sustainable development (#6—drinking water and sanitation) and with SDG numbers 3, 11, 12, 14, and 17.

Impaired glymphatic clearance in multiple system atrophy: A diffusion spectrum imaging study

IntroductionImpaired α-synuclein clearance is pivotal in the pathogenesis of neurodegenerative diseases. We evaluated glymphatic clearance in multiple system atrophy (MSA) patients using advanced imaging. MethodsForty-four MSA patients (11 with MSA-parkinsonian type [MSA-P] and 33 with MSA-cerebellar type [MSA-C]) and 30 healthy controls were studied using diffusion spectrum magnetic resonance imaging (DSI-MRI). Diffusivities were measured along the x-, y-, and z-axes to calculate the Analysis Along the Perivascular Space (ALPS) index. Comparisons of the ALPS index were conducted between MSA patients and controls and among MSA subtypes. The ALPS index correlation with the Unified Multiple System Atrophy Rating Scale (UMSARS) scores was also analyzed. ResultsThe ALPS index differed significantly between patients with MSA and healthy controls, with lower values observed in the former (1.46 ± 0.17 versus1.63 ± 0.12, p < 0.001). Both MSA-P and MSA-C patients had lower ALPS-index (1.40 ± 0.13, p < 0.001; 1.47 ± 0.18, p = 0.003, respectively), but there was no significant difference between the two (p = 0.22). No correlation was found between the ALPS index and clinical scores for UMASRS I (r = −0.08, p = 0.61), UMASRS II (r = −0.04, p = 0.81), or UMASRS I + II (r = −0.05, p = 0.74). ConclusionMSA patients show reduced glymphatic clearance as measured by the ALPS index, underscoring the utility of this imaging method in neurodegenerative disease research.

A practical evaluation of measures derived from compressed sensing diffusion spectrum imaging.

Diffusion Spectrum Imaging (DSI) using dense Cartesian sampling of q-space has been shown to provide important advantages for modeling complex white matter architecture. However, its adoption has been limited by the lengthy acquisition time required. Sparser sampling of q-space combined with compressed sensing (CS) reconstruction techniques has been proposed as a way to reduce the scan time of DSI acquisitions. However prior studies have mainly evaluated CS-DSI in post-mortem or non-human data. At present, the capacity for CS-DSI to provide accurate and reliable measures of white matter anatomy and microstructure in the living human brain remains unclear. We evaluated the accuracy and inter-scan reliability of 6 different CS-DSI schemes that provided up to 80% reductions in scan time compared to a full DSI scheme. We capitalized on a dataset of 26 participants who were scanned over eight independent sessions using a full DSI scheme. From this full DSI scheme, we subsampled images to create a range of CS-DSI images. This allowed us to compare the accuracy and inter-scan reliability of derived measures of white matter structure (bundle segmentation, voxel-wise scalar maps) produced by the CS-DSI and the full DSI schemes. We found that CS-DSI estimates of both bundle segmentations and voxel-wise scalars were nearly as accurate and reliable as those generated by the full DSI scheme. Moreover, we found that the accuracy and reliability of CS-DSI was higher in white matter bundles that were more reliably segmented by the full DSI scheme. As a final step, we replicated the accuracy of CS-DSI in a prospectively acquired dataset (n = 20, scanned once). Together, these results illustrate the utility of CS-DSI for reliably delineating in vivo white matter architecture in a fraction of the scan time, underscoring its promise for both clinical and research applications.

Effect of extragalactic magnetic field on cascade gamma-ray emission

The intensity of diffuse cascade gamma-ray emission produced in electromagnetic cascades when ultra-high energy cosmic rays propagate in extragalactic space is discussed. It is obtained that in the range of ~107—109 eV diffuse cascade gamma-ray spectra weakly depends on extragalactic magnetic field value. Thus, there is no need to refine extragalactic magnetic field models to estimate the intensity of cascade emission in this energy range.