Prior-guided individualized thalamic parcellation based on local diffusion characteristics.

Comprising numerous subnuclei, the thalamus intricately interconnects the cortex and subcortex, orchestrating various facets of brain functions. Extracting personalized parcellation patterns for these subnuclei is crucial, as different thalamic nuclei play varying roles in cognition and serve as therapeutic targets for neuromodulation. However, accurately delineating the thalamic nuclei boundary at the individual level is challenging due to intersubject variability. In this study, we proposed a prior-guided parcellation (PG-par) method to achieve robust individualized thalamic parcellation based on a central-boundary prior. We first constructed probabilistic atlas of thalamic nuclei using high-quality diffusion MRI datasets based on the local diffusion characteristics. Subsequently, high-probability voxels in the probabilistic atlas were utilized as prior guidance to train unique multiple classification models for each subject based on a multilayer perceptron. Finally, we employed the trained model to predict the parcellation labels for thalamic voxels and construct individualized thalamic parcellation. Through a test-retest assessment, the proposed prior-guided individualized thalamic parcellation exhibited excellent reproducibility and the capacity to detect individual variability. Compared with group atlas registration and individual clustering parcellation, the proposed PG-par demonstrated superior parcellation performance under different scanning protocols and clinic settings. Furthermore, the prior-guided individualized parcellation exhibited better correspondence with the histological staining atlas. The proposed prior-guided individualized thalamic parcellation method contributes to the personalized modeling of brain parcellation.

The parcellation of cingulate cortex in neonatal period based on resting-state functional MRI.

The human cingulate cortex (CC) is a complex region that is characterized by heterogeneous cytoarchitecture, connectivity, and function, and it is associated with various cognitive functions. The adult CC has been divided into various subregions, and this subdivision is highly consistent with its functional differentiation. However, only a few studies have focused on the function of neonatal CC. The aim of this study was to describe the cingulate segregation and the functional connectivity of each subdivision in full-term neonates (n = 60) based on resting-state functional magnetic resonance imaging. The neonatal CC was divided into three subregions, and each subregion showed specific connectivity patterns. The anterior cingulate cortex was mainly correlated with brain regions related to the salience (affected) network and default mode network (DMN), the midcingulate cortex was related to motor areas, and the posterior cingulate cortex was coupled with DMN. Moreover, we found that the cingulate subregions showed distinct functional profiles with major brain networks, which were defined using independent component analysis, and exhibited functional lateralization. This study provided new insights into the understanding of the functional specialization of neonatal CC, and these findings may have significant clinical implications, especially in predicting neurological disorder.

Characterization of DBD plasma actuator with ZnO nanowire arrays.

Researches in the plasma actuation are increasingly scrutinizing the methodology to enhance the thrust density for the application in the aerodynamic flow control. In this paper, a new method has been proposed and experimentally evaluated. This method is based on the deposition of nanoscaled structures on the electrode surface and the tuning of the applied voltages and frequency. It is found that the thrust enhancement rate resulted from the incorporation of the nanostructures could be approximately 78%, relative to the controlled group, under 14 kV and 7 kHz. However, a threshold effect has been founded across all of the tested samples, where lower applied voltage and frequency could lead to the decrease in the thrust generation. Capacitor charging effects are basically not sensitive to the introduction of the nanostructures in electrical characteristic. Other experimental features and electric field simulation results also indicate the effectiveness of introducing nanoscaled structures into DBD plasma actuators, thus providing a new way to improve mechanical performance.

Structural, photocatalytic and photoelectrochemical properties of porous ZnO nanosheets prepared by air cold plasma.

Porous ZnO nanosheets with different thickness were prepared on zinc substrate by air cold plasma for photocatalytic degradation and photoelectrochemical water splitting. The ZnO nanosheets consisted of nanocrystallines with high-density oxygen-related defects characterized by the strong red luminescence. The UV absorption tended to be saturated as the thickness increased, and the saturation occurred at a thickness of about 2.3µm. Under UV irradiation (365 nm), the 2.3µm thick sample with higher content of oxygen vacancies and oxygen interstitials showed the highest photocatalytic activity (and higher than P25 TiO2) in degradation of gaseous ethyl acetate. Due to the excellent UV-vis absorption ability and the effective transfer of photogenerated carriers, the ZnO nanosheets with thickness of 3.3µm showed a photocurrent density as high as 0.22 mA cm-2at -0.28 V (versus Ag/AgCl) under AM 1.5 G 100 mW cm-2.

A facile hot-pressing process for fabricating flexible top electrodes of piezoelectric ZnO nanowire nanogenerators.

We report a facile and effective hot-pressing strategy for fabricating the flexible top electrode for a piezoelectric nanogenerator (PENG). Flexible stainless steel (SUS) foil was employed as the bottom electrode and substrate of the device. Zinc oxide nanowires (ZnO NWs) were grown on SUS substrate through the hydrothermal synthesis method. The top electrode of Zn foil was combined with dielectric polydimethylsiloxane (PDMS) film using the hot-pressing process. The resulting top electrode is thick enough to enable the device to generate piezoelectric output differently under bending conditions. The PENG devices generated an output voltage of about 2.2 V and an output current of 8 nA under the optimum operating conditions. The devices fabricated by the hot-pressing process were robust enough to retain their generating ability after thousands of bending and releasing cycles.

Nanocoating covalent organic frameworks on nickel nanowires for greatly enhanced-performance supercapacitors.

Nanocoatings of covalent organic frameworks (COFs) on nickel nanowires (NiNWs) have been designed and successfully fabricated for the first time, which showed greatly enhanced electrochemical performances for supercapacitors. The specific capacitance of electrodes based on as-fabricated COFs nanocoatings reached up to 314 F g-1 at 50 A g-1, which retained 74% of the specific capacitance under the current density of 2 A g-1. The ultrahigh current density makes the charge-discharge process extremely rapid. The outstanding electrochemical performances of COFs nanocoating on NiNWs make it an ideal candidate for supercapacitors. And the nanocoating-design can also give a guidance for application of COFs in high-performance energy storages.

Carbon Nanotube-Based Chemiresistive Sensors.

The development of simple and low-cost chemical sensors is critically important for improving human life. Many types of chemical sensors have been developed. Among them, the chemiresistive sensors receive particular attention because of their simple structure, the ease of high precise measurement and the low cost. This review mainly focuses on carbon nanotube (CNT)-based chemiresistive sensors. We first describe the properties of CNTs and the structure of CNT chemiresistive sensors. Next, the sensing mechanism and the performance parameters of the sensors are discussed. Then, we detail the status of the CNT chemiresistive sensors for detection of different analytes. Lastly, we put forward the remaining challenges for CNT chemiresistive sensors and outlook the possible opportunity for CNT chemiresistive sensors in the future.

Parkinson's disease: in vivo metabolic changes in the frontal and parietal cortices in 6-OHDA treated rats during different periods.

This study aims to investigate metabolic changes in frontal and parietal cortices in the 6-OHDA induced Parkinson's rats. Ratios of N-acetyl-aspartic acid/creatine (NAA/Cr), choline/creatine (Cho/Cr), and glumatic acid and glutamine glutaminic acid/creatine (Glx/Cr) of regions of interests (ROIs) in the frontal and parietal cortices, and the substantia nigra were analyzed. NAA/Cr, Cho/Cr and Glx/Cr in the frontal and parietal cortices in the lesion side did not show any significant differences two weeks after operation compared with the contralateral side (p > 0.05). NAA/Cr in the frontal cortex in the lesion side was significantly lower in the five weeks after operation; Cho/Cr remained normal; Glx/Cr increased (p < 0.05), and all ratios of parietal cortex were normal. In the eight weeks after operation, NAA/Cr in the frontal cortex in the lesion side was lower than that of the five weeks (p < 0.01), Cho/Cr still remained normal while Glx/Cr was higher than before (p < 0.01). Regarding the parietal cortex, NAA/Cr increased significantly, while Cho/Cr and Glx/Cr remained normal. In the 12 weeks after operation, NAA/Cr, Cho/Cr and Glx/Cr in frontal cortex were consistent with that of the eight weeks, while they remained at the normal level in parietal cortex. The NAA/Cr in the substantia nigra decreased and Cho/Cr increased significantly during 2-8 weeks, and remained at the same level during 8-12 weeks. There are metabolic disturbances in PD rats. The transient hyperfunction in the parietal cortex can be considered as a compensation for the dysfunction of the frontal cortex and substantia nigra.

Ionic Current Extraction in an Electrostatic-Fluid-Based Tripolar System for Ethanol Sensing.

We report a microfluidics-based tripolar system to extract the ionic current from the gas discharge process for gas sensing, which is structurally and fluidically compatible with the gas chromatography (GC) systems. The tripolar system was fabricated based on the microelectromechanical systems technology and tested as a gas detector with the assistance of a GC column under different external factors, that is, the applied voltages and the gas flow rates. An analytical model is proposed to address the ion extraction behavior under the coupling effect of the electric field and flow field. The extracted ionic current is demonstrated to have a higher signal quality than the corresponding discharge current for ethanol sensing, regarding the signal-to-noise ratio and selectivity. Moreover, the variation behavior of the ionic current corroborates the description of the physical model. The miniaturized tripolar system constitutes an effective approach to ion extraction for gas sensing under the working voltage down to 40 V, which can be applied as a gas detector in a portable GC system.

Morphological changes in the central sulcus of children with isolated growth hormone deficiency versus idiopathic short stature.

In this study, the morphological changes in the central sulcus between children with isolated growth hormone deficiency (IGHD) and those with idiopathic short stature (ISS) were analyzed. Thirty children with IGHD (peak growth hormone < 5 µg/L) and 30 children with ISS (peak growth hormone > 10.0 µg/L) were included. Morphological measurements of the central sulcus were obtained from T1-weighted MRIs using BrainVISA, including the average sulcal width, maximum depth, average depth, top length, bottom length, and depth position-based profiles (DPPs). The bilateral average width of the central sulci was significantly wider, while the left maximum depth and right average depth of the central sulcus were significantly smaller, in children with IGHD than in children with ISS. There were no significant differences in the right maximum depth, left average depth, or bilateral top length and bottom length of the central sulcus between groups. The DPPs of the middle part of both central sulci (corresponding to the hand motor activation area) and the inferior part of the right central sulcus (corresponding to the oral movement area) near the Sylvian fissure were significantly smaller in children with IGHD than in controls before false discovery rate (FDR) correction. However, all the above significant DPP sites disappeared after FDR correction. There were significant morphological changes in the three-dimensional structure of the central sulcus in children with IGHD, which were the outcome of other more essential cortical or subcortical changes, resulting in their relatively slower development in motor, cognitive, and linguistic functional performance.

Cerebral glucose metabolism: Influence on perihematomal edema formation after intracerebral hemorrhage in cat models.

BACKGROUND: Most intracerebral hemorrhage (ICH) imaging studies focus on structural brain changes. Stereotactic neuroimaging techniques such as magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) are helpful in the diagnosis of ICH, monitoring the subsequent recovery and investigating its functional mechanisms. PURPOSE: To explore the influence of the changes in cerebral glucose metabolism on perihematomal edema formation in an experimental cat model of ICH. MATERIAL AND METHODS: Forty-eight cats were divided into 1 sham operation group (6 cats) and 7 ICH model groups (42 cats)". The ICH model groups were injected with 1.0 ml autologous nonheparinized blood into their thalami using accurate stereotactic guidance apparatus. MRI and (18)F-fluorodeoxyglucose (FDG) PET/CT scans were acquired at 2, 6, 12, 24, 48, 72, and 120 h following the intervention. Pearson's correlation test was used to evaluate the association between T2-weighted signal intensity and the edema volume. Student's t test and q test were used to identify the times of significant temporal changes. RESULTS: The volume of perilesional edema did not significantly increase from 2 h to 12 h after ICH, but then increased by 229.4% at 24 h, peaked (by 273.5%), and steadily decreased by 72 h. The FDG intensity in perihematomal edema tissues was markedly reduced 2 h after ICH on PET images, reached its lowest level at 12 h, and then steadily increased at 24 h and 48 h. The changes of standard absorption value (SUV) in perihematomal edema were consistent with those of FDG intensity. CONCLUSION: Perihematomal glucose metabolism abnormalities have a close relationship with the formation of vasogenic edema. Furthermore, abnormal glucose metabolism may impair capillary integrity and increase blood-brain barrier permeability.

Parkinson's disease: functional changes in frontal and parietal cortex using 18 F- fluoro-deoxy glucose positron emission tomography/computed tomography.

BACKGROUND: In Parkinson's disease (PD) there is increasing evidence to suggest motor function changes of the cerebral cortex occur in addition to the pathological changes in the extrapyramidal system. AIMS: To explore the functional changes in the frontal and parietal cortex in PD cat model. SETTINGS AND DESIGN: Twenty-four healthy male cats were divided into four animal model groups with the injection of 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP), and one control group. MATERIALS AND METHODS: Cats in both the animal model and control groups were observed for the behavioral changes. They were also examined by 18 F-fluoro-deoxy glucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT). Region of Interest (ROI) was determined by 18 F-FDG intensity and semi-quantitative analysis was employed after detecting the standard absorption value (SUV). Statistical Analysis : Statistical significance was evaluated by ANOVA. RESULTS: Compared to control group, the 18 F-FDG intensity and SUV were found normal on both the sides of frontal and parietal cortex in the PD models on the second day (P > 0.05), and on the fifth day, they were reduced significantly on both the sides of frontal cortex exclusively (P < 0.05). Moreover on the eighth day, the SUV of both frontal cortexes was reduced, while it was increased in both parietal cortex (P < 0.05). Finally on the eleventh day, the SUV remained stable in both the frontal cortex, and was back to normal level in both the parietal cortex. CONCLUSIONS: Functional disorders exist in the frontal cortex of PD animals and aggravate with time. Transient functional enhancement in the parietal cortex of PD cats might be a compensation for the dysfunction of frontal cortex.

Preparation of Electrochemical Sensor Based on Zinc Oxide Nanoparticles for Simultaneous Determination of AA, DA, and UA.

ZnO nanoparticles (NPs) were synthesized using a hydrothermal method. Scanning electron microscope (SEM) and X-ray diffraction have been used for characterizing the synthesized ZnO NPs. An electrochemical sensor was fabricated using ZnO NPs-modified glassy carbon electrode for simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The proposed electrochemical sensor exhibited excellent detection performance toward three analytes, demonstrating that it can potentially be applied in clinical applications. The results indicated the ZnO NPs-modified electrode can detect AA in the concentrations range between 50 and 1,000 µM. The ZnO NPs-modified electrode can detect DA in the concentrations range between 2 and 150 µM. The ZnO NPs-modified electrode can detect UA in the concentrations range between 0.2 and 150 µM. The limits of detections of AA, DA, and UA using ZnO NPs-modified electrode were calculated to be 18.4, 0.75, and 0.11 µM, respectively.

MEMS-Based Ionization Gas Sensors for VOCs with Array of Nanostructured Silicon Needles.

Although volatile organic compound samples can be detected by gas nanosensors in adsorption principles, extreme concentrations of target gases imply the excessive adsorption, which would lead to a long recovery time and even a shortened lifetime. Herein, we report the observations of the ionization current sensing behavior on the volatile organic compounds in an ionization gas sensor with silicon-based nanostructures. The micro ionization gas sensor consists of a pair of silicon microneedle array electrodes covered by nanolayer structures and a microdischarge gas gap. The dynamic response behaviors of the sensors to the exposure of ethanol, acetone, and 2-chloroethyl ethyl sulfide have been carefully scrutinized. The sensor exhibits sound performances to the high-concentration volatile organic compounds with a fast-recovery property and could generate effective responses well at 36 V, namely, the safety operation voltages. It could be well understood by the Jesse effect where small proportion of impurities in gases could lead to an intensive increase in the overall ionization probability. Besides, the reproducibility, recovery time, sensitivity, and selectivity properties have been systematically characterized.

Morphological changes of the cerebral cortex between children with isolated growth hormone deficiency and idiopathic short stature.

The growth hormone (GH)-insulin-like growth factor-I (IGF-I) axis plays an important role in normal brain development, and GH deficiency inevitably affects the growth of the cerebral cortex. This study was designed to analyze morphological differences in gray matter volume, cortical surface area, and gray matter thickness between children with isolated growth hormone deficiency (IGHD) and children with idiopathic short stature (ISS). Twenty-four children with IGHD (mean age 9.42 years, peak GH < 5 µg/l) and 24 controls with ISS (mean age 9.21 years, peak GH > 10 µg/l) were included. High-resolution three-dimensional T1-weighted MRIs were acquired at participants' first visit. Measurements of gray matter volume, cortical surface area and gray matter thickness were obtained using FreeSurfer. The total and regional differences between groups were statistically analyzed. Correlations between the FreeSurfer results and GH and IGF-I levels were also obtained. The gray matter volume, cortical surface area and gray matter thickness of the total brain and of the bilateral hemispheres of children with IGHD were significantly smaller than those of children with ISS (all P values < 0.05). All the measurements had similar cortical distributions between groups but varied across regions. Cortical regions with significant differences in the mean gray matter volume and surface area were mainly distributed around the bilateral central sulci and the lateral and basal parts of the temporal lobes (all P values < 0.05). There were negative correlations between gray matter volume, cortical surface area and GH levels, and the right hemispheric and total cortical surface area correlated significantly with GH levels (all P values < 0.05) in children with IGHD. There were significant positive correlations between gray matter volume, cortical surface area and IGF-I levels (all P values < 0.05) in both groups, except for in left hemispheric gray matter volume in children with ISS. Children with IGHD have significant morphological changes in the cerebral cortex, which were partially influenced by GH and IGF-I levels. These cortical changes may be related to deficits in their relatively slower development in intelligence, motor performance, and other functions.

Brain asymmetry differences between Chinese and Caucasian populations: a surface-based morphometric comparison study.

Asymmetry has been proved to exist in the human brain structure, function and behavior. Most of the existing brain asymmetry findings are originated from the western populations, while studies about the brain structural and functional asymmetries in East Asians are limited. Extensive evidence suggested that cultural differences, e.g. education and language, may lead to differences in brain structure and function between races. Therefore, we hypothesized that differences in brain structural asymmetries exist between East Asians and Westerners. In this study, we performed a comprehensive surface-based morphometric (SBM) analysis of brain asymmetries in cortical thickness, volume and surface area in two well-matched groups of right-handed, Chinese (n = 45) and Caucasian (n = 45) young male adults (age = 22-29 years). Our results showed consistent inter-hemispheric asymmetries in the three brain morphological measures in multiple brain regions in the Chinese young adults, including the temporal, frontal, parietal, occipital, insular cortices and the cingulate gyrus. Comparing with the Caucasians, the Chinese group showed greater structural asymmetry in the frontal, temporal, occipital and insular cortices, and smaller asymmetry in the parietal cortex and cingulate gyrus. These findings could provide a new neuroanatomical basis for understanding the distinctions between East Asian and Caucasian in brain functional lateralization.

Fetal ocular development in the second trimester of pregnancy documented by 7.0 T postmortem Magnetic Resonance Imaging.

Few investigators have analyzed fetal ocular growth with Magnetic Resonance Imaging (MRI) of high magnetic strength. Our purpose is to obtain normative biometrics for fetal ocular development in the second trimester of pregnancy. Sixty specimens with a gestational age (GA) of 12-23 weeks were scanned using a 7.0 T MRI scanner. The linear interocular and binocular distances (IOD and BOD, respectively), globe diameter (GD) and lens diameter (LD) were measured on the transverse section of the largest diameter of the eyeballs. The three dimensional (3D) visualization model of the eyeball was reconstructed with Amira software. Then, the globe and lens volumes (GV and LV, respectively) were obtained. All the measurements were plotted as a function of GA. The fetal ocular structures in the second trimester of pregnancy could be clearly delineated on 7.0 T postmortem MRI images. All the linear measurements logarithmically increased with GA, while, the volumetric measurements linearly increased with GA. Postmortem MRI of high magnetic strength can clearly document fetal ocular growth in the second trimester of pregnancy. These quantitative data may be a valuable reference for the assessment of normal fetal eyeball development in clinical settings and may be considered a supplement to anatomical investigations.

Efficacy of combined treatment with vacuum sealing drainage and recombinant human epidermal growth factor for refractory wounds in the extremities and its effect on serum levels of IL-6, TNF-α and IL-2.

The objective of this study was to investigate the efficacy of combined treatment with vacuum sealing drainage (VSD) and recombinant human epidermal growth factor (rhEGF) for refractory wounds in the extremities, and its effect on serum levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and IL-2. Ninety-eight patients with refractory wounds in the extremities were recruited and randomly divided into the combined treatment group (underwent VSD and rhEGF treatment) and control group (underwent VSD only) with 49 cases each. Formation of granulation tissue on the wound surface was assessed and scored. The wound healing rate was calculated after 1 week of treatment, and the time of complete healing was recorded. Serum levels of IL-6, IL-2, and TNF-α were measured using enzyme-linked immunosorbent assay. After 1 week of treatment, granulation tissue formation on wound surfaces was significantly improved (p<0.05) compared with that before treatment in both groups. Moreover, granulation tissue formation on wound surfaces was superior in the combined treatment group than in the control group (p<0.05). The wound healing rate was 63.50±4.75% in the combined treatment group and 31.79±3.52% in the control group, and the difference was statistically significant (p<0.05). The time of complete healing was 15.11±2.24 days in the combined treatment group and 19.63±2.76 days in the control group, and the difference was statistically significant (p<0.05). The serum levels of IL-6, IL-2, and TNF-α, in the two groups were significantly lower than those before treatment (p<0.05). Moreover, the levels in the combined treatment group were significantly lower than those in the control group (p<0.05). In conclusion, combined treatment with VSD and rhEGF reduced inflammation and shortened the time of complete healing of refractory wounds in the extremities. Measurement of the levels of related inflammatory factors provided a reference for the prognosis of refractory wounds.

D-beta-hydroxybutyrate inhibits the apoptosis of PC12 cells induced by 6-OHDA in relation to up-regulating the ratio of Bcl-2/Bax mRNA.

D-beta-hydroxybutyrate (DbetaHB) is a predominant member of ketone bodies produced by hepatocytes and, to a lesser extent, by astrocytes. It is an alternative source of energy in the brain when glucose supply is depleted such as during starvation. It has been reported that ketone bodies could protect dopaminergic culture. However, the biological function of DbetaHB in Parkinson disease (PD) is still unclear. In the present work, we investigated the role of DbetaHB in protecting rat pheochromocytoma (PC12) cells from apoptosis induced by 6-Hydroxydopamine (6-OHDA). DbetaHB rescued PC12 cells from apoptotic death induced by 6-OHDA by MTT assay, acridine orange (AO) staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining and the activity of caspase-3. DbetaHB prevented the decrease of cell viability and the increase of caspase-3 activity induced by 6-OHDA in a dose-dependent manner in PC12 cells. AO and TUNEL staining showed that DbetaHB prevented the apoptosis of PC12 cells induced by 6-OHDA. The ratio of Bcl-2/Bax at mRNA levels, which regulates the apoptosis of PC12 cells when exposed to 6-OHDA, increased when DbetaHB was preincubated. The data showed that DbetaHB inhibited the apoptosis of PC12 cells induced by 6-OHDA in relation to up-regulating the ratio of Bcl-2/Bax mRNA.

Room-temperature fabrication of a three-dimensional porous silicon framework inspired by a polymer foaming process.

A room-temperature routine for the fabrication of a three-dimensional silicon porous framework inspired by a polymer foaming process is introduced. The obtained micron-sized pores can be further modified by hydrothermal growth of nanowires to form a hierarchical porous composite framework.