A disease warranting attention from neurosurgeons: primary central nervous system post-transplant lymphoproliferative disorder.

Background: Primary central nervous system post-transplant lymphoproliferative disorder (PCNS-PTLD) is a rare condition, posing diagnostic and treatment challenges, with histological biopsy essential for diagnosis. Standardized treatment protocols are lacking. This disease requires urgent attention due to the increasing number of organ transplant surgeries and the use of immunosuppressive agents. Methods: From 2020 to 2023, our center diagnosed five patients with PCNS-PTLD. We reviewed their clinical records and conducted a comprehensive analysis of 22 literatures on PCNS-PTLD cases following renal transplantation or allogeneic hematopoietic stem cell transplantation (HSCT). Results: Four patients had previously received a kidney transplant, one had undergone allogeneic HSCT. The median time from the last transplant surgery to the diagnosis of PCNS-PTLD differs between kidney transplant (21.5 years) and allogeneic HSCT (9 months). Common symptoms included motor weakness (n = 4), headache (n = 2), confusion (n = 2), and nausea (n = 2), with ring-enhancing (n = 5), typically solitary (n = 3) and supratentorial (n = 3) lesions on imaging. Diagnosis involved robot-assisted stereotactic brain biopsy (n = 4) or craniotomy (n = 1), all showing Epstein-Barr virus and CD20 positivity. Most cases (n = 4) were monomorphic diffuse large B-cell lymphoma. Treatment included rituximab (n = 3), surgical resection (n = 2), zanubrutinib (n = 1), whole-brain radiation (n = 1), and methotrexate (n = 1). At the last follow-up, the median duration of follow-up for all patients was 19 months. During this time, 3 patients had died and 2 patients were still alive. Conclusion: In patients with a history of kidney transplantation or allogeneic HSCT who are on long-term immunosuppressive therapy, any neurological symptoms, particularly the presence of supratentorial ring-enhancing masses in the brain on imaging, whether solitary or multiple, should raise high suspicion for this disease, warranting a timely brain biopsy. Additionally, we found that besides reducing immunosuppressants, zanubrutinib may be a potential, safe, and effective treatment for this condition. Moreover, post-surgical administration of rituximab in conjunction with whole-brain radiotherapy also appears to be a potentially safe and effective approach.

High-Performance Contact-Doped WSe2 Transistors Using TaSe2 Electrodes.

Two-dimensional (2D) transitional metal dichalcogenides (TMDs) have garnered significant attention due to their potential for next-generation electronics, which require device scaling. However, the performance of TMD-based field-effect transistors (FETs) is greatly limited by the contact resistance. This study develops an effective strategy to optimize the contact resistance of WSe2 FETs by combining contact doping and 2D metallic electrode materials. The contact regions were doped using a laser, and the metallic TaSe2 flakes were stacked on doped WSe2 as electrodes. Doping the contact areas decreases the depletion width, while introducing the TaSe2 contact results in a lower Schottky barrier. This method significantly improves the electrical performance of the WSe2 FETs. The doped WSe2/TaSe2 contact exhibits an ultralow Schottky barrier height of 65 meV and a contact resistance of 11 kΩ·µm, which is a 50-fold reduction compared to the conventional Cr/Au contact. Our method offers a way on fabricating high-performance 2D FETs.

Misdirection due to early magnetoencephalographic presentation and management in Rasmussen encephalitis: a case report.

Rasmussen encephalitis is a rare and unexplained chronic brain hemispheric inflammatory disease. We report a case of epilepsy in which magnetoencephalography showed dipoles localized only in the operculum. Because the patient's clinical presentation and examination findings did not meet the diagnostic criteria for Rasmussen encephalitis, he underwent cortical electroencephalogram (ECoG) record and limited resection surgery. However, the seizures were not relieved after surgery, and imaging findings showed significant features of hemisphere atrophy. This young male patient was eventually diagnosed with Rasmussen encephalitis and the seizures was completely vanished following hemispherectomy. His data can provide a reference for the early identification of this devastating disease.

Twist-angle-dependent momentum-space direct and indirect interlayer excitons in WSe2/WS2 heterostructure.

Interlayer excitons (ILEs) in the van der Waals (vdW) heterostructures of type-II band alignment transition metal dichalcogenides (TMDCs) have attracted significant interest owing to their unique exciton properties and potential in quantum information applications. However, the new dimension that emerges with the stacking of structures with a twist angle leads to a more complex fine structure of ILEs, presenting both an opportunity and a challenge for the regulation of the interlayer excitons. In this study, we report the evolution of interlayer excitons with the twist angle in the WSe2/WS2 heterostructure and identify the direct (indirect) interlayer excitons by combining photoluminescence (PL) and density functional theory (DFT) calculations. Two interlayer excitons with opposite circular polarization assigned to the different transition paths of K-K and Q-K were observed. The nature of the direct (indirect) interlayer exciton was confirmed by circular polarization PL measurement, excitation power-dependent PL measurement and DFT calculations. Furthermore, by applying an external electric field to regulate the band structure of the WSe2/WS2 heterostructure and control the transition path of the interlayer excitons, we could successfully realize the regulation of interlayer exciton emission. This study provides more evidence for the twist-angle-based control of heterostructure properties.

The Effect of the Pre-Strain Process on the Strain Engineering of Two-Dimensional Materials and Their van der Waals Heterostructures.

Two-dimensional (2D) materials and their van der Waals stacked heterostructures (vdWH) are becoming the rising and glowing candidates in the emerging flexible nanoelectronics and optoelectronic industry. Strain engineering proves to be an efficient way to modulate the band structure of 2D materials and their vdWH, which will broaden understanding and practical applications of the material. Therefore, how to apply desired strain to 2D materials and their vdWH is of great importance to get the intrinsic understanding of 2D materials and their vdWH with strain modulation. Here, systematic and comparative studies of strain engineering on monolayer WSe2 and graphene/WSe2 heterostructure are studied by photoluminescence (PL) measurements under uniaxial tensile strain. It is found that contacts between graphene and WSe2 interface are improved, and the residual strain is relieved through the pre-strain process, which thus results in the comparable shift rate of the neutral exciton (A) and trion (AT) of monolayer WSe2 and graphene/WSe2 heterostructure under the subsequent strain release process. Furthermore, the PL quenching occurred when the strain is restored to the original position also indicates the pre-strain process to 2D materials, and their vdWH is important and necessary for improving the interface contacts and reducing the residual strain. Thus, the intrinsic response of the 2D material and their vdWH under strain can be obtained after the pre-strain treatment. These findings provide a quick, fast and efficient way to apply desired strain and also have important significance in guiding the use of 2D materials and their vdWH in the field of flexible and wearable devices.

Pyroptosis-Related Genes as Markers for Identifying Prognosis and Microenvironment in Low-Grade Glioma.

Low-grade glioma (LGG) is one of the most common brain tumors and often develops into the worst glioblastoma (GBM). Pyroptosis is related to inflammation and immunization. It has been demonstrated to influence the progression of a variety of cancers. However, the value of pyrosis-related genes (PRGs) in LGG remains unclear. Public TCGA-LGG data are used to analyze the differential expression and genetic variation of PRGs in LGG. Subsequently, this paper identifies pyroptosis-related subtypes and constructs prognostic models. This paper analyzes the expression and function of selected CASP5 in LGG and constructs a ceRNA regulatory network. Final CASP5-related immune infiltration analysis and methylation analysis are performed. Most PRGs are differentially expressed and altered in LGG. Subtypes and prognostic models based on PRGs not only have good functions but also have a great connection with immune infiltration. Enrichment analysis of PRGs with prognostic value of LGG also shows functions correlated mainly with immunity and inflammation. CASP5 is significantly differentially expressed in different grades of gliomas and different prognoses. Despite fewer mutations, CASP5 has a clear correlation for both immune cells and immune checkpoint molecules in the LGG microenvironment. Its methylation may also have a role in the prognosis of LGG. This paper shows the association of pyrosis-related subtypes, prognostic models, and genes, with immune infiltration.

Comprehensive analysis of expression, prognosis and immune infiltration for TIMPs in glioblastoma.

BACKGROUND: Tissue inhibitors of metalloproteinase (TIMP) family proteins are peptidases involved in extracellular matrix (ECM) degradation. Various diseases are related to TIMPs, and the primary reason is that TIMPs can indirectly regulate remodelling of the ECM and cell signalling by regulating matrix metalloproteinase (MMP) activity. However, the link between TIMPs and glioblastoma (GBM) is unclear. OBJECTIVE: This study aimed to explore the role of TIMP expression and immune infiltration in GBM. METHODS: Oncomine, GEPIA, OSgbm, LinkedOmics, STRING, GeneMANIA, Enrichr, and TIMER were used to conduct differential expression, prognosis, and immune infiltration analyses of TIMPs in GBM. RESULTS: All members of the TIMP family had significantly higher expression levels in GBM. High TIMP3 expression correlated with better overall survival (OS) and disease-specific survival (DSS) in GBM patients. TIMP4 was associated with a long OS in GBM patients. We found a positive relationship between TIMP3 and TIMP4, identifying gene sets with similar or opposite expression directions to those in GBM patients. TIMPs and associated genes are mainly associated with extracellular matrix organization and involve proteoglycan pathways in cancer. The expression levels of TIMPs in GBM correlate with the infiltration of various immune cells, including CD4+ T cells, macrophages, neutrophils, B cells, CD8+ T cells, and dendritic cells. CONCLUSIONS: Our study inspires new ideas for the role of TIMPs in GBM and provides new directions for multiple treatment modalities, including immunotherapy, in GBM.

Remarkable quality improvement of as-grown monolayer MoS2 by sulfur vapor pretreatment of SiO2/Si substrates.

Monolayer MoS2 is a direct bandgap semiconductor which is believed to be one of the most promising candidates for optoelectronic devices. Chemical vapor deposition (CVD) is the most popular method to synthesize monolayer MoS2 with a large area. However, many defects are always found in monolayer MoS2 grown by CVD, such as sulfur vacancies, which severely degrade the performance of devices. This work demonstrates a concise and effective method for direct growth of high quality monolayer MoS2 by using SiO2/Si substrates pretreated with sulfur vapor. The MoS2 monolayer obtained using this method shows about 20 times PL intensity enhancement and a much narrower PL peak width than that grown on untreated substrates. Detailed characterization studies reveal that MoS2 grown on sulfur vapor pretreated SiO2/Si substrates has a much lower density of sulfur vacancies. The synthesis of monolayer MoS2 with high optical quality and low defect concentration is critical for both fundamental physics studies and potential practical device applications in the atomically thin limit.