Application of neuroendoscopic surgical techniques in the assessment and treatment of cerebral ventricular infection

Cerebral ventricular infection (CVI) is one of the most dangerous complications in neurosurgery because of its high mortality and disability rates. Few studies have examined the application of neuroendoscopic surgical techniques (NESTs) to assess and treat CVI. This multicenter, retrospective study was conducted using clinical data of 32 patients with CVI who were assessed and treated by NESTs in China. The patients included 20 men and 12 women with a mean age of 42.97 years. NESTs were used to obliterate intraventricular debris and pus, fenestrate or incise the intraventricular compartment and reconstruct cerebrospinal fluid circulation, and remove artificial material. Intraventricular irrigation with antibiotic saline was applied after neuroendoscopic surgery (NES). Secondary hydrocephalus was treated by endoscopic third ventriculostomy or a ventriculoperitoneal shunt. Neuroendoscopic findings of CVI were used to classify patients into Grade Ⅰ(n = 3), Grade Ⅱ(n = 13), Grade Ⅲ(n = 10), and Grade Ⅳ(n = 6) CVI. The three patients with grade ⅠCVI underwent one NES, the 23 patients with grade Ⅱ/Ⅲ CVI underwent two NESs, and patients with grade Ⅳ CVI underwent two (n = 3) or three (n = 3) NESs. The imaging features and grades of neuroendoscopy results were positively related to the number of neurosurgical endoscopic procedures. Two patients died of multiple organ failure and the other 30 patients fully recovered. Among the 26 patients with secondary hydrocephalus, 18 received ventriculoperitoneal shunt and 8 underwent endoscopic third ventriculostomy. There were no recurrences of CVI during the 6- to 76-month follow-up after NES. Application of NESTs is an innovative method to assess and treat CVI, and its neuroendoscopic classification provides an objective, comprehensive assessment of CVI. The study trial was approved by the Institutional Review Board of Beijing Shijitan Hospital, Capital Medical University, China.

Synthesis and performance of Ca-α/β-SiAlON composites from tailings

Ca-α/β-SiAlON composites were prepared using Ca-α/β-SiAlON powder synthesized from gold ore tailings, which contained abundant Si and Al elements as the major raw materials together with minor additives, through a pressure-less sintering method. The influ- ences of sintering temperature on the phase composition and mierostrueture of the composites were analyzed. The scanning electron micros- copy images of the composites show the interlacing of grains with elongated columnar, short columnar and plate-like morphologies. The composites sintered at 1520℃ for 6 h have a flexural strength of 352 MPa, Vickers hardness of 11.2 GPa, and fracture toughness of 4.8 MPa·m1/2. The relative content of each phase in the products is I（Ca-α-SiAION）：I（β-SiAlON）：I（Fe3Si） = 23：74：3, where Ii stands for the dif- fraction peak intensity of phase i.

Atomistic study on tensile fracture of densified silica glass and its dependence on strain rate

Densification is a major feature of silica glass that has received widespread attention.This work investigates the fracture behavior of densified silica glass upon uniaxial tension based on atomistic simulations.It is shown that the tensile strength of the silica glass approximately experiences a parabolic reduction with the initial density,while the densified samples show a faster power growth with the increase of strain rate.Meanwhile,the fracture strain and strain energy increase significantly when the densification exceeds a certain threshold,but fracture strain tends to the same value and strain energy becomes closer for different densified samples at extreme high strain rate.Microscopic views indicate that all the cracks are formed by the aggregation of nanoscale voids.The transition from brittleness fracture to ductility fracture can be found with the increase of strain rate,as a few fracture cracks change into a network distribution of many small cracks.Strikingly,for the high densified sample,there appears an evident plastic flow before fracture,which leads to the crack number less than the normal silica glass at the high strain rate.Furthermore,the coordinated silicon analysis suggests that high strain rate tension will especially lead to the transition from 4-to 3-fold Si when the high densified sample is in plastic flow.

Mechanical and microstructural response of densified silica glass under uniaxial compression: Atomistic simulations

We investigate the mechanical and microstructural changes of the densified silica glass under uniaxial loading-unloading via atomistic simulations with a modified BKS potential. The stress–strain relationship is found to include three respective stages: elastic, plastic and hardening regions. The bulk modulus increases with the initial densification and will undergo a rapid increase after complete densification. The yield pressure varies from 5 to 12 GPa for different densified samples. In addition, the Si–O–Si bond angle reduces during elastic deformation under compression, and 5-fold Si will increase linearly in the plastic deformation. In the hardening region, the peak splitting and the new peak are both found on the Si–Si and O–O pair radial distribution functions, where the 6-fold Si is increased. Instead, the lateral displacement of the atoms always varies linearly with strain, without evident periodic characteristic. As is expected, the samples are permanently densified after release from the plastic region, and the maximum density of recovered samples is about 2.64 g/cm^3, which contains 15 % 5-fold Si, and the Si–O–Si bond angle is less than the ordinary silica glass. All these findings are of great significance for understanding the deformation process of densified silica glass.

Migration behavior and aggregation mechanism of SiC particles in silicon melt during directional solidification process

SiC inclusions in a multicrystalline silicon ingot have a negative effect on the performance of solar cells.The migration behavior and aggregation mechanism of SiC particles in the silicon melt during the directional solidification process was studied.Results show that SiC particles collide and aggregate in the melt due to the effect of melt flow.Larger aggregation of SiC particles is easily deposited at the bottom of the melt,whereas smaller SiC particles are pushed to the top of melt.Meanwhile,the particles migrate to the edge of melt under the effect of electromagnetic force.Furthermore,the enrichment region of SiC particles can be controlled by adjusting the temperature field distribution of the melt.With an increase of the melt temperature,the SiC particles are enriched at the top of the silicon ingot,indicating that SiC particles can be effectively separated from silicon.

Efficacy analysis of flexible neuroendoscopy combined with dry-field techniques in the treatment of chronic subdural hematoma

Chronic subdural hematoma (CSDH) is a common and frequently occurring disease in neurosurgery, whose incidence accounts for around 10% of all intracranial hematomas. There have been many theories about the mechanism of CSDH, including acute subdural hematoma, slow hemorrhage after bridge vein injury, and traumatic subdural effusion evolution With improvements in medical imaging technology and related basic research, the perception of CSDH as an inflammatory vascular proliferative disease has gradually reached consensus In addition to head trauma, brain atrophy leading to expanded subdural space is the premise and primary reason for the occurrence of CSDH in the older adult population.

热激活延迟荧光材料敏化的螺烯对映体有机发光二极管:一种提高电致圆偏振发光效率的新策略

为了提高基于手性荧光分子的有机圆偏振发光二极管(CPOLED)器件效率,本文提出了一种全新的热激活延迟荧光材料敏化圆偏振发光(TAS-CPL)的策略.设计合成了一对具有刚性骨架的螺烯对映体(P)-HAI和(M)-HAI作为器件的手性发光客体,研究发现螺烯对映体具有高的热稳定性、手性构型稳定性、良好的光物理性质,尤其是具有强的CPL性质,其荧光不对称因子(|g_(lum)|)约为6×10^(-3).与直接以螺烯对映体作为发光客体的CP-OLED相比,通过TADF敏化剂热激活敏化螺烯对映体的CP-OLED表现出更低的启动电压(2.6 V)、更低的效率滚降(1.9%,亮度为1000 cd m^(-2))以及增加四倍的最大外量子效率(EQEmax,5.3%),螺烯对映体的电致发光不对称因子分别为-2.3×10^(-3)和+3.0×10^(-3).这是首例基于热激活延迟荧光材料敏化圆偏振发光的CP-OLED,为提高手性荧光分子的电致圆偏振发光效率提供了有效策略.

Retinol dehydrogenase 10 promotes metastasis of glioma cells via the transforming growth factor-β/SMAD signaling pathway

Background:Glioma is the most common primary malignant tumor in the central nervous system. Because of the resistance of glioma to chemoradiotherapy and its aggressive growth, the survival rate of patients with glioma has not improved. This study aimed to disclose the effect of retinol dehydrogenase 10 (RDH10) on the migration and invasion of glioma cells, and to explore the potential mechanism.Methods:Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the expression levels of RDH10 in healthy glial cells and glioma cells. Human glioma cell strains, U87 and U251, were infected with negative control or RDH10-interfering lentiviruses. RT-PCR and Western blotting were performed to determine the knockdown efficiency. Scratch and transwell assays were used to assess cell migration and invasion after RDH10 knockdown. Finally, changes in transforming growth factor-β (TGF-β)/SMAD signaling pathway-related expression were examined by Western blotting. Differences between groups were analyzed by one-way analysis of variance.Results:RDH10 was highly expressed in glioma cells. Compared with the control group, RDH10 knockdown significantly reduced RDH10 messenger RNA and protein expression levels in U87 and U251 glioma cells (U87: 1.00 ± 0.08 vs. 0.22 ± 0.02, t= 16.55, P < 0.001;U251: 1.00 ± 0.17 vs. 0.39 ± 0.01, t= 6.30, P < 0.001). The scratch assay indicated that compared with the control group, RDH10 knockdown significantly inhibited the migration of glioma cells (U87: 1.00% ± 0.04% vs. 2.00% ± 0.25%, t= 6.08, P < 0.01;U251: 1.00% ± 0.11% vs. 2.48% ± 0.31%, t= 5.79, P < 0.01). Furthermore, RDH10 knockdown significantly inhibited the invasive capacity of glioma cells (U87: 97.30 ± 7.01 vs. 13.70 ± 0.58, t = 20.36, P < 0.001;U251: 96.20 ± 7.10 vs. 18.30 ± 2.08, t = 18.51, P < 0.001). Finally, Western blotting demonstrated that compared with the control group, downregulation of RDH10 significantly inhibited TGF-β expression, phosphorylated SMAD2, and phosphorylated SMAD3 (TGF-β: 1.00 ± 0.10 vs. 0.53 ± 0.06, t= 7.05, P < 0.01;phosphorylated SMAD2: 1.00 ± 0.20 vs. 0.42 ± 0.17, t= 4.01, P < 0.01;phosphorylated SMAD3: 1.00 ± 0.18 vs. 0.41 ± 0.12, t= 4.12, P < 0.01).Conclusion:RDH10 knockdown might inhibit metastasis of glioma cells via the TGF-β/SMAD signaling pathway.

Whole-genome sequencing reveals the evolutionary trajectory of HBV-related hepatocellular carcinoma early recurrence

Patients with hepatocellular carcinoma(HCC)have poor long-term survival following curative resection because of the high rate of tumor early recurrence.Little is known about the trajectory of genomic evolution from primary to early-recurrent HCC.In this study,we performed whole-genome sequencing(WGS)on 40 pairs of primary and early-recurrent hepatitis B virus(HBV)-related HCC tumors from patients who received curative resection,and from four patients whose primary and recurrent tumor were extensively sampled.We identified two recurrence patterns:de novo recurrence(18/40),which developed genetically independently of the primary tumor and carried different HCC drivers,and ancestral recurrence(22/40),which was clonally related to the primary tumor and progressed more rapidly than de novo recurrence.We found that the recurrence location was predictive of the recurrence pattern:distant recurrence tended to display the de novo pattern,whereas local recurrence tended to display the ancestral pattern.We then uncovered the evolutionary trajectories based on the subclonal architecture,driver-gene mutations,and mutational processes observed in the primary and recurrent tumors.Multi-region WGS demonstrated spatiotemporal heterogeneity and polyclonal,monophyletic dissemination in HCC ancestral recurrence.In addition,we identified recurrence-specific mutations and copy-number gains in BCL9,leading to WNT/β-catenin signaling activation and an immuneexcluded tumor microenvironment,which suggests that BCL9 might serve as a new therapeutic target for recurrent HCC.Collectively,our results allow us to view with unprecedented clarity the genomic evolution during HBV-related HCC early recurrence,providing an important molecular foundation for enhanced understanding of HCC with implications for personalized therapy to improve patient survival.

Numerical simulation of dynamic characteristics of a water surface vehicle with a blended-wing-body shape

The blended-wing-body shape vehicle is a new type of water surface vehicle with a large square coefficient. The interference of the wave systems under a high speed condition is more significant for the blended-wing-body shape vehicle and the dynamic characteristics of the new type vehicle are very different from that of a traditional vehicle. In this paper, the implicit volume of fluid（VOF） method is adopted to simulate the wave resistance of the high speed blended wing body vehicle, and a semi-relative reference frame method is proposed to compute the maneuvering coefficients. The effects of the navigation speed, the drift angle and the rotating radius are studied. The dimensional analysis method is used to assess the influence of Fr and L/R on the results. The wave making resistance coefficient against the speed sees a large fluctuation because of the serious wave interference. The lateral rotation maneuvering characteristics under the surface navigation condition is nonlinear and more complex than under the under water condition, which is quite different to control.

Neuroendoscopic Evaluation and Treatment for Cerebral Ventricular Infection

To the Editor： Cerebral ventricular infection （CVI）, also termed ependymitis, involves an inflammatory response in the cerebral ventricular system. CVI is characterized by leukocytosis in tile cerebrospinal fluid （CSF）, a positive culture result of pathogenic bacteria, and imaging changes in tile ventricles.