Altered functional connectivity in default mode network maintains attention task performance in school-age children with frontal lobe tumor.

This study examines functional brain network changes in children with frontal lobe tumors (FLT). Ten pediatric FLT patients from Beijing Tiantan Hospital and 20 healthy children were compared in terms of cognitive performance and resting-state functional magnetic resonance imaging (rs-fMRI) connectivity. The FLT group showed lower cognitive performance, particularly in visual and working memory domains, but had comparable attention abilities to the healthy controls. There were notable differences in connectivity between the default mode network (DMN) and sensorimotor network (SMN) in both groups. The FLT group also displayed a significant reduction in local efficiency in the left lateral parietal area within the DMN. Importantly, reduced DMN-SMN connections and increased DMN-lateral prefrontal cortex connectivity may facilitate maintaining attention and memory tasks in FLT children. This study sheds light on how the brains of children with FLT adapt, preserving "normal" attention functions despite frontal lobe damage.

Structural and functional changes following brain surgery in pediatric patients with intracranial space-occupying lesions.

We explored the structural and functional changes of the healthy hemisphere of the brain after surgery in children with intracranial space-occupying lesions. We enrolled 32 patients with unilateral intracranial space-occupying lesions for brain imaging and cognitive assessment. Voxel-based morphometry and surface-based morphometry analyses were used to investigate the structural images of the healthy hemisphere. Functional images were analyzed using regional homogeneity, amplitude of low-frequency fluctuations, and fractional-amplitude of low-frequency fluctuations. Voxel-based morphometry and surface-based morphometry analysis used the statistical model built into the CAT 12 toolbox. Paired t-tests were used for functional image and cognitive test scores. For structural image analysis, we used family-wise error correction of peak level (p < 0.05), and for functional image analysis, we use Gaussian random-field theory correction (voxel p < 0.001, cluster p < 0.05). We found an increase in gray matter volume in the healthy hemisphere within six months postoperatively, mainly in the frontal lobe. Regional homogeneity and fractional-amplitude of low-frequency fluctuations also showed greater functional activity in the frontal lobe. The results of cognitive tests showed that psychomotor speed and motor speed decreased significantly after surgery, and reasoning increased significantly after surgery. We concluded that in children with intracranial space-occupying lesions, the healthy hemisphere exhibits compensatory structural and functional effects within six months after surgery. This effect occurs mainly in the frontal lobe and is responsible for some higher cognitive compensation. This may provide some guidance for the rehabilitation of children after brain surgery.

Does right hemisphere compensate for the left in school-age children with large left middle fossa arachnoid cysts?

BACKGROUND: To assess the cognitive function changes and brain network neuroplasticity in school-age children having large (diameter > 5 cm) left middle fossa arachnoid cyst (MFACs). METHODS: Eleven patients and 22 normal controls (NC) between 6 and 14 years of age were included. The CNS Vital Signs (CNS VS) were administered for cognitive assessment. The differences of cognitive data and functional connectivity (FC) in resting-state functional magnetic resonance imaging (rs-fMRI) were compared between the patient group and the NC group. The correlations between the altered FC and cognitive data in the patient group were assessed. RESULTS: Patient group had significantly poorer attention (including Complex Attention, Sustained Attention, Simple Attention, Cognitive Flexibility, and Executive Function) and memory function (Visual Memory and Working Memory) than the NC group (uncorrected p-value, p-unc < 0.05). Whole-brain local correlation (LCOR) analysis showed an extensively lower LCOR in the patient group (voxel threshold p-unc < 0.001, cluster-size threshold of false discovery rate adjusted p (p-FDR) < 0.001). Functional connectivity (FC) analysis showed that bilateral frontal and temporal lobes connectivity in the patient group was significantly lower than the NC group (p-FDR < 0.05). Seed-based FC analysis indicated that there was altered FC between the right temporal lobe and the left temporal-parietal/temporal-occipital area (p-FDR < 0.05). In the patient group, most of the altered FC had a negative correlation to the cognitive score, while the FC in the right temporal lobe-left temporal-occipital area positively correlated to Verbal/Visual Memory (r = 0.41-0.60, p-FDR < 0.05). In correlation analysis between clinical data and cognitive score, the only significant result was a low correlation between cyst size and Reaction Time (-0.30--0.36, P-FDR < 0.05). CONCLUSIONS: School-aged children with large left MFAC showed significantly lower cognitive performance primarily in attention and memory domains. Distinct from neuroplasticity in a unilateral brain lesion, compensation in the healthy hemisphere in MFAC patients was sparse.

Microstructure, Mechanical Properties and Fatigue Crack Growth Behavior of Gas Tungsten Arc Welding Welded Joint of the Hastelloy N Alloy.

Hastelloy N alloy is an excellent oxidation and corrosion-resistant material, which is selected as the shell material for the main vessel of molten salt reactors (MSRs). In this work, we conducted double-sided gas tungsten arc welding (GTAW) on 4 mm thick Hastelloy N alloy plates to examine the microstructure and mechanical properties of the welded joints. The S-N curve was obtained by fatigue test. The experimental results show that fatigue cracks initiate along the weld toe and propagate inward in a fan-shaped pattern. The hardness is highest in the heat-affected zone (HAZ). The fracture mode observed was trans-granular. The plastic zone in the initial stages of crack propagation remained relatively minimal. However, it gradually expanded during subsequent stages of the process. It is noteworthy that the crack propagation process often involves the development of secondary cracks, accompanied by profound plasticity-induced closure effects. The results of our investigation demonstrate that the welded joint exhibits excellent fatigue performance.

Early recovery of cognition and brain plasticity after surgery in children with low-grade frontal lobe tumors.

Background: Low-grade frontal lobe tumors (LGFLT) can be cured through total resection, but surgical trauma could impair higher-order cognitive function. We aim to characterize the short-term natural cognitive recovery and brain plasticity in surgically-treated pediatric patients with LGFLT. Methods: Ten pediatric patients with LGFLT were enrolled. Their cognitive function was assessed before the surgery (S0), in the first month post-surgery (S1), and 3-6 months post-surgery (S2), using the CNS Vital Signs battery. DTI and rs-fMRI were performed during the same time periods. Changes of cognition and image metrics between S1>S0 and S2>S1 were analyzed. Results: The Motor Speed (MotSp) and Reaction Time (RT) scores significantly decreased in S1 and recovered in S2. Rs-fMRI showed decreased functional connectivity (FC) between the bilateral frontal lobes and bilateral caudates, putamina, and pallidi in S1>S0 (voxel threshold p -unc < 0.001 , cluster threshold p -FDR < 0.05 ). In S2>S1, FC recovery was observed in the neighboring frontal cortex areas ( p -unc < 0.001 , p -FDR < 0.05 ). Among them, the FC in the caudates-right inferior frontal gyri was positively correlated to the RT ( p -FDR < 0.05 ). A DTI Tract-based spatial statistics (TBSS) analysis showed decreased fractional anisotropy and axial diffusivity mainly in the corticospinal tracts, cingulum, internal capsule, and external capsule at 0-6 months post-surgery (TFCE- p < 0.05 ). The DTI metrics were not associated with the cognitive data. Conclusion: Processing speed impairment after an LGFLT resection can recover naturally within 3-6 months in school-age children. Rs-fMRI is more sensitive to short-term brain plasticity than DTI TBSS analysis. "Map expansion" plasticity in the frontal-basal ganglia circuit may contribute to the recovery.

Study on Fatigue Performance of Pulsed Tungsten Inert Gas Welding Joint of Duplex Stainless Steel Thin Tube.

To solve the shortage of austenite phase precipitation caused by nitrogen loss in the welding process of UNS S2205 duplex stainless steel (DSS), shielding gas nitriding was investigated by adding different N2 contents in Ar shielding gas during the welding process. A good thin-walled pipe butt joint was formed using the pulsed tungsten inert gas (P-TIG) welding method with Ar-N2 shielding gas. High cycle fatigue tests of the weld joints were conducted to study the effect of shielding gas nitriding on the fatigue properties. Fatigue tests at three stress levels of 225 MPa, 270 MPa, and 360 MPa were carried out on the weld joints with different N2 contents, and the fatigue samples were all fractured in the high temperature heat-affected zone (H-HAZ). Within the current process parameters, the fatigue life of the 4 vol.% N2 welded joints was optimal. Fatigue striations appeared in the fatigue crack propagation zone, and the transient fracture zone was similar to the tensile fracture. Under the low-stress level, the area of the crack propagation zone under 4 vol.% N2 was the highest, the tear ridges all expanded around the crack source area, and the fatigue crack propagation zone presented a radial distribution. The proliferation and expansion of dislocations were mainly carried out in the austenite grains, and the dislocation density of the fatigue specimens under 4 vol.% N2 was smaller than that of the Ar specimens. Shielding gas nitriding effectively improved the balance of the two-phase ratio and the hardness of austenite phase, optimized the internal slip system, inhibited the proliferation of dislocations in the austenite phase, and improved the fatigue life of weld joints.

Application of the CNS vital signs test and WISC-IV in the cognitive assessment of Chinese pediatric patients with intra-cranial space occupying lesion.

BACKGROUND: A fast and reliable neurocognitive assessment tool is required for pediatric patients with an intracranial space-occupying lesion (ICSOL). METHODS: A cross-sectional study was conducted on 41 pediatric patients having ICSOL. Cognitive abilities were assessed using both WISC-IV and CNS Vital Signs (CNS VS). All domains are compared to the normative data. Spearman's correlation analysis is performed between domains in two batteries. RESULTS: In the WISC-IV, CPI, PSI, and WMI are significantly lower than the normative level. In the CNS VS, NCI, Memory domains, Reaction Time, Social Acuity, and Sustained Attention are significantly lower. Six domains in the CNS VS, including Complex Attention, Sustained Attention, Cognitive Flexibility, Executive Function, Processing Speed, and Social Acuity, positively correlate to the PSI or CPI in the WISC-IV. Sixty percent (9/15) of domains in the CNS VS negatively correlate to the size of ISCOL. The FSIQ in the WISC-IV is significantly associated with patients' parent education level. CONCLUSION: Compared to the WISC-IV, CNS VS takes less time, but measures more domains. CNS VS is more sensitive to the size of ICSOL but is not affected by patients' parent education level. A healthy control group is warranted for interpreting the results in Chinese participants.

Postoperative Complications of Microscopic Fenestration for Middle Fossa Arachnoid Cysts: A Retrospective Study of 38 Cases and Literature Review.

INTRODUCTION: Middle fossa arachnoid cyst (MFAC) is one of the most common cranial cysts in children, and the various postoperative complications following cyst fenestration represent a major concern. We conducted a retrospective study in our department and performed a systematic review of the literature to identify the risk factors for complications. METHODS: A retrospective survey was conducted in 38 patients with MFAC (<14 years) who underwent microscopic fenestration from January 2019 to December 2020. Postoperative complications, including postoperative hemorrhage/hematoma, subdural hygroma (SH), cranial nerve palsy, postoperative central nervous system infection, and cerebrospinal fluid (CSF) leak, were collected. A systematic PubMed search for cohort studies on surgically treated MFAC published after 1980 was performed. The postoperative complications in the included studies were illustrated. RESULTS: The overall complication rate in our series was 7.9%, among whom, 9 patients (23.7%) developed postoperative SH, one of which required cyst-peritoneal shunting. Patients who developed SH were significantly younger (4.0 ± 1.8 vs. 6.3 ± 3.4 years, p = 0.012). Binary logistic analysis showed that a lower age could be a risk factor for developing SH (odds ratio: 0.738, p = 0.067). One patient developed a subdural hematoma. No cranial nerve palsy or CSF leak was observed. Eighteen studies were included in the systematic review, comprising 649 cases of MFAC. The most common complication was SH (4.9%), and the postoperative complication rates were similar between the microscopic and endoscopic techniques. CONCLUSION: The complication rate of MFAC fenestration is considerable. SH is the most common postoperative complication, and it mostly occurs in young children. Strict surgical indications should be applied for young children.

Changes in a sensorimotor network, occipital network, and psychomotor speed within three months after focal surgical injury in pediatric patients with intracranial space-occupying lesions.

BACKGROUND: Studies on cognition and brain networks after various forms of brain injury mainly involve traumatic brain injury, neurological disease, tumours, and mental disease. There are few related studies on surgical injury and even fewer pediatric studies. This study aimed to preliminarily explore the cognitive and brain network changes in children with focal, unilateral, well-bounded intracranial space-occupying lesions (ISOLs) in the short term period after surgery. METHODS: We enrolled 15 patients (6-14 years old) with ISOLs admitted to the Department of Pediatric Neurosurgery of the Beijing Tiantan Hospital between July 2020 and August 2021. Cognitive assessment and resting-state functional magnetic resonance imaging (rs-fMRI) were performed. Regional homogeneity (Reho), seed-based analysis (SBA) and graph theory analysis (GTA) were performed. Paired T-test was used for statistical analysis of cognitive assessment and rs-fMRI. Gaussian random-field theory correction (voxel p-value < 0.001, cluster p-value < 0.05) was used for Reho and SBA. False discovery rate correction (corrected p value < 0.05) for GTA. RESULTS: Our results showed that psychomotor speed decreased within three months after surgery. Further, rs-fMRI data analysis suggested that sensorimotor and occipital network activation decreased with low information transmission efficiency. CONCLUSION: We prudently concluded that the changes in cognitive function and brain network within three months after surgery may be similar to ageing and that the brain is vulnerable during this period.

A Numerical Simulation Method Considering Solid Phase Transformation and the Experimental Verification of Ti6Al4V Titanium Alloy Sheet Welding Processes.

A prediction model of the welding process of Ti-6Al-4V titanium alloy was established by using the finite element method, which was used to evaluate the phase composition, residual stress and deformation of the welded joints of Ti-6Al-4V sheets with different processes (including tungsten inert gas welding, TIG, and laser beam welding, LBW). The Ti-6Al-4V structures of TIG welding and LBW are widely used in marine engineering. In order to quantitatively study the effects of different welding processes (including TIG welding and LBW) on the microstructure evolution, macro residual stress and deformation of Ti6Al4V titanium alloy sheets during welding, a unified prediction model considering solid-state phase transformation was established based on the ABAQUS subroutine. In this paper, LBW and TIG welding experiments of 1.6 mm thick Ti-6Al-4V titanium alloy sheets were designed. The microstructure distribution of the welded joints observed in the experiment was consistent with the phase composition predicted by the model, and the hardness measurement experiment could also verify the phase composition and proportion. From the residual stress measured by experiment and the residual stress and deformation calculated by finite element simulation of LBW and TIG weldments, it is concluded that the effect of phase transformation on residual stress is mainly in the weld area, which has an effect on the distribution of tensile and compressive stress in the weld area. The overall deformation of the welded joint is mainly related to the welding process, and the phase transformation only affects the local volume change of the weld seam. Importantly, the phase composition and residual stress, which are scalar fields, calculated by the established model can be introduced into the numerical analysis of structural fracture failure as input influence factors.

The truths behind the statistics of surgical treatment for hypertensive brainstem hemorrhage in China: a review.

Hypertensive brainstem hemorrhage (HBSH) is of high morbidity and mortality rate. But many clinical studies were written in Chinese and had not been reviewed. A systemic review of Chinese clinical studies for HBSH was performed. A systemic literature search in PubMed, Web of Science, China National Knowledge Infrastructure, and Weipu database and Wanfang database up to March 2020 was performed. Clinical control studies including a surgical evacuation (SE) group and a conservative management (CM) group were included. The clinical outcome and mortality rate were compared. Ten cohort studies were included, involving 944 participants (304 in the SE group and 640 in the CM group). All included patients were comatose, with the average age ranged from 45 to 65 years old. Among five studies using mRS or GOS as outcome score, a total of 16.6% (89/535) of patients achieve self-maintenance with minor disabilities, including 26.8% (34/127) in the SE group and 13.5% (55/408) in the CM group. The overall mortality rate in the SE group was 27.6%, ranged from 9.3 to 60% among different studies. The overall mortality rate in the CM group was 60.6%, ranged from 18.5 to 100.0%. Elder and comatose HBSH patients are not contraindicated for surgery. The review showed that this group of patients obtained a better outcome and lower mortality rate after surgical treatment. The quality of included studies was relatively low, but a high-level clinical study on HBSH is of great difficulty, as both clinicians and patients faced various sociological issues rather than pure medical problems.

[Simulation method of skull remodellingsurgeryfor infant with craniosynostosis].

Craniofacial malformation caused by premature fusion of cranial suture of infants has a serious impact on their growth. The purpose of skull remodeling surgery for infants with craniosynostosis is to expand the skull and allow the brain to grow properly. There are no standardized treatments for skull remodeling surgery at the present, and the postoperative effect can be hardly assessed reasonably. Children with sagittal craniosynostosis were selected as the research objects. By analyzing the morphological characteristics of the patients, the point cloud registration of the skull distortion region with the ideal skull model was performed, and a plan of skull cutting and remodeling surgery was generated. A finite element model of the infant skull was used to predict the growth trend after remodeling surgery. Finally, an experimental study of surgery simulation was carried out with a child with a typical sagittal craniosynostosis. The evaluation results showed that the repositioning and stitching of bone plates effectively improved the morphology of the abnormal parts of the skull and had a normal growth trend. The child's preoperative cephalic index was 65.31%, and became 71.50% after 9 months' growth simulation. The simulation of the skull remodeling provides a reference for surgical plan design. The skull remodeling approach significantly improves postoperative effect, and it could be extended to the generation of cutting and remodeling plans and postoperative evaluations for treatment on other types of craniosynostosis.

Predictive Factors of Postoperative Peritumoral Brain Edema after Meningioma Resection.

BACKGROUND: Postoperative peritumoral brain edema (PTBE) is the progressively exacerbating cerebral edema following meningiomas resection. OBJECTIVE: The study aims to identify the predictive factors of postoperative PTBE. MATERIALS AND METHODS: A retrospective study was conducted on the 117 cases of patients who underwent meningioma. The histopathological features of the tumors were re-assessed according to WHO 2016 classification. Clinical and pathohistological features were analyzed. RESULTS: Thirteen patients (11.1%) were diagnosed having postoperative PTBE. Preoperative seizure (odds ratio [OR] = 6.125, P = 0.039) and histological prominent nucleoli (OR = 3.943, P = 0.039) were the independent risk factors for postoperative PTBE. Meningiomas with a parietal localization were more likely to develop postoperative PTBE (OR = 3.576, P = 0.054). Brain invasion and large tumor volume did not increase complication rate. Preoperative edema index was significantly higher in brain invasive meningiomas (3.0 ± 2.2 versus 1.8 ± 1.7, P = 0.001). Patients having moderate preoperative PTBE were prone to the complication (21.4% versus 7.9%, P = 0.100). CONCLUSIONS: Preoperative seizure were the predictive factors for postoperative PTBE. Careful venous protection during the operation may be helpful, especially for tumors locating in the parietal lobe. Prominent nucleoli observed in postoperative pathology should warrant surgeons' attention. Comprehensive perioperative management is essential for these patients.

Study on Hydrogen Diffusion Behavior during Welding of Heavy Plate.

For the multi-layer and multi-pass welding process of the heavy plate, the hydrogen diffusion behavior was numerically simulated to study the effect of solid-state phase transition (SSPT) on the hydrogen diffusion in the thickness direction, and the influence of the residual stress-induced diffusion after SSPT. The calculation results were compared with the experimental results. The comparison shows that the distribution of hydrogen concentration in the direction of thickness was in good agreement. The position with the most severe cold cracking sensitivity was located at a 20-30 mm depth from the top surface in this article. After welding, the hydrogen concentration in this position was kept at a high level for a long time under the effect of the size-constraint effect of the heavy plate and the existence of welding residual stress gradient. In addition, the SSPT reduced the residual stress level of weld metal (WM) significantly, increased that of the heat affected zone (HAZ), and the hydrogen was redistributed under the influence of stress. In the process of phase transformation, the parameters of hydrogen diffusion property of the material changed dramatically in a short time, the hydrogen diffusion coefficient increased in order of magnitude, and the solubility decreased in order of magnitude. This directly led to the upward diffusion of hydrogen in WM, and produced a self-gathering effect. For a welded joint of heavy plate, the self-gathering effect between passes was effective in the short-range and ineffective in the long-range.

Spinal arachnoiditis followed by intrathecal tigecycline therapy for central nervous system infection by extremely drug-resistant Acinetobacter baumannii.

In prior research, intrathecal tigecycline was successfully used to treat central nervous system infection by extensively drug-resistant Acinetobacter baumannii. However, little is known about its safe dose and adverse reactions. This study reports the case of a 28-year-old male patient who was diagnosed with central nervous system infection by extensively drug-resistant A. baumannii after the removal of a ventriculoperitoneal shunt. Intravenous and intrathecal tigecycline were administrated simultaneously. Spinal arachnoiditis was discovered after nine doses of intrathecal tigecycline. Spinal arachnoiditis was resolved after discontinuation of the antibiotic. This is the first report of an adverse reaction to intrathecal tigecycline. The case was complicated by spinal arachnoiditis, which obstructed the assessment of cerebrospinal fluid. The appropriate dose and administration schedule of intrathecal tigecycline remain to be determined.

Shifting subdural fluid collection and hydrocephalus after foramen magnum decompression for basilar invagination.

Background: Postoperative hydrocephalus and subdural fluid collection (SFC) have been reported as the rare complications following foramen magnum decompression in patients with Chiari malformation.Case Description: The paper reports the case of a 63-year-old female patient who underwent foramen magnum decompression for basilar invagination. The patient developed a shifting, bilateral SFC and subsequent acute hydrocephalus. A ventriculoperitoneal shunting was performed and the clinical symptom resolved. The dramatic change in CSF distribution supported the diagnosis of external hydrocephalus, which was associated with a postoperative cervical pseudomeningocele.Conclusions: Postoperative SFC in patients underwent foramen magnum decompression may harbor different mechanisms. Subdural drainage for patients having external hydrocephalus may have a higher recurrence rate.

LncRNA-LET relieves hypoxia-induced injury in H9c2 cells through regulation of miR-138.

Ischemic heart disease (IHD) is a common cardiovascular disease, occurs when coronary artery blood circularity cannot match with the heart's need. The present work attempted to study the effects of long noncoding RNA (lncRNA) low expression in tumor (LET) on the progression of IHD. H9c2 cells were injured by hypoxia to mimic a cell model of IHD. The effects of lncRNA-LET on hypoxia-injured H9c2 cells were tested by using cell counting kit-8 assay, flow cytometry, and Western blot analysis. MicroRNA-138 (miR-138) expression was tested by a quantitative real-time polymerase chain reaction, and the expression of c-Jun N-terminal kinase (JNK) and p38MAPK (p38-mitogen-activated protein kinase) proteins was measured by Western blot analysis. We found that hypoxia exposure significantly repressed the viability of H9c2 cells, and induced apoptosis. Meanwhile, phosphorylation of JNK and p38MAPK was enhanced by hypoxia. The expression of lncRNA-LET was repressed by hypoxia. Overexpression of lncRNA-LET attenuated hypoxia-induced injury in H9c2 cells. Moreover, miR-138 was a downstream effector of lncRNA-LET, that miR-138 was highly expressed in lncRNA-LET-overexpressed cell. The cardioprotective effects of lncRNA-LET were abolished when miR-138 was silenced. In conclusion, this study revealed the cardioprotective function of lncRNA-LET. lncRNA-LET conferred its cardioprotective effects possibly via upregulation of miR-138 and thus repressing the JNK and p38MAPK pathways.

Self-Gathering Effect of the Hydrogen Diffusion in Welding Induced by the Solid-State Phase Transformation.

The hydrogen diffusion in welding was investigated by using thermal-mechanical-hydrogen diffusion sequential coupled procedures based on finite element method. A self-gathering effect induced by the solid-state phase transformation was discovered. Because of the self-gathering effect, the hydrogen concentration in weld metal was accumulated to a peak value which can be larger than the initial hydrogen concentration in molten pool, and subsequently the hydrogen concentration in heat affect zone was redistributed. In multi-pass welding, the gathered effect not only happened inside a weld pass, but also in the inter-pass, which further increased the sensitivity of the hydrogen-assisted cold cracking. Controlling should be adopted to restrain the hydrogen accumulation. Welding stress evolution during the solid-state phase transformation process had limited effect on the hydrogen diffusion.