Weak localization behavior observed in graphene grown on germanium substrate

Two dimensional electron systems (2DES) usually show the weak localization behavior in consequence of electron interaction in the limited dimension. Distinct from other 2DES, the monolayer graphene, due to the chirality, exhibits unique weak localization behavior sensitive to not only inelastic but also elastic carrier scattering. Grain boundaries, which usually exist in monolayer graphene, are apparently related to the elastic carrier scattering process, thus affecting the weak localization behavior. However, their effect is scarcely studied due to the lack of an ideal platform. Here, a complementary system consisting of both single-crystalline graphene grown on Ge (110) and poly-crystalline graphene grown on Ge (111) is constructed. From the comparison of magnetoresistivity measurements, the weak localization effect is found to be greatly enhanced for the poly-crystalline graphene on Ge(111) compared to the single-crystalline graphene on Ge(110). The degraded transport performance in graphene/Ge(111) is due to the presence of grain boundary in poly-crystalline graphene, which results in the enhanced elastic intervalley scattering. In addition, the inelastic scattering originating from the strong electron-electron interaction at low temperature also contributes to weak localization of poly-crystalline graphene/Ge(111)

Genomic Instability in Cerebrospinal Fluid Cell-Free DNA Predicts Poor Prognosis in Solid Tumor Patients with Meningeal Metastasis

Genomic instability (GI), which leads to the accumulation of DNA loss, gain, and rearrangement, is a hallmark of many cancers such as lung cancer, breast cancer, and colon cancer. However, the clinical significance of GI has not been systematically studied in the meningeal metastasis (MM) of solid tumors. Here, we collected both cerebrospinal fluid (CSF) and plasma samples from 56 solid tumor MM patients and isolated cell-free ctDNA to investigate the GI status using a next-generation sequencing-based comprehensive genomic profiling of 543 cancer-related genes. According to the unfiltered heterozygous mutation data-derived GI score, we found that 37 (66.1%) cases of CSF and 3 cases (6%) of plasma had a high GI status, which was further validated by low-depth whole-genome sequencing analysis. It is demonstrated that a high GI status in CSF was associated with poor prognosis, high intracranial pressure, and low Karnofsky performance status scores. More notably, a high GI status was an independent poor prognostic factor of poor MM-free survival and overall survival in lung adenocarcinoma MM patients. Furthermore, high occurrences of the co-mutation of TP53/EGFR, TP53/RB1, TP53/ERBB2, and TP53/KMT2C were found in MM patients with a high GI status. In summary, the GI status in CSF ctDNA might be a valuable prognostic indicator in solid tumor patients with MM

Prognostic factors and outcome of surgically treated patients with brain metastases of non‐small cell lung cancer

Background Brain metastases (BM) are a common consequence of lung cancer and surgery is effective; however, the factors affecting survival after surgery are unclear. The aim of this study was to identify the outcomes and prognoses of post‐metastasectomy patients with BM from non‐small cell lung cancer (NSCLC) at a single institution over a 15‐year period. Methods NSCLC patients who had undergone BM surgery were retrospectively identified. Survival was analyzed using the Kaplan–Meier curve, and univariate and multivariate factors associated with survival were identified using the Cox proportional hazards model. Results The median overall survival was 9.8 months, 18 (14.8%) patients survived > 24 months, and 6 (4.9%) > 36 months. The one and two‐year survival rates were 41% and 18.6%, respectively. Univariate analysis revealed that recursive partitioning analysis (RPA) classification, Karnofsky Performance Scale (KPS) scores, BM number, extracranial metastasis status, different lesion locations, resection extent, postoperative treatment, and salvage therapy after recurrence significantly influenced patient survival. The different treatment modalities for primary lesions also affected postoperative survival. KPS ≥ 70, RPA class I/II, and postoperative chemotherapy were independent factors that decreased the risk of death from BM. Interestingly, the initial onset of intracranial lesions could increase the risk of death from BM. Conclusion A KPS score ≥ 70, RPA class I/II, and postoperative chemotherapy could benefit post‐metastasectomy patients with BM from NSCLC. Conversely, the initial onset of intracranial lesions is an unfavorable factor that increases the risk of death. These findings support the use of personalized therapy for patients with BM from NSCLC

Plasmonic ELISA for Sensitive Detection of Disease Biomarkers with a Smart Phone-Based Reader

Abstract Serum myoglobin is one of the earliest markers for the diagnosis of acute myocardial infarction. It is, therefore, critical to develop a point-of-care testing technology for myoglobin detection. In this work, we reported a sensitive plasmonic immunoassay-based on enzyme-mediated localized surface plasmon resonance change of gold nanorods for the point-of-care testing detection of myoglobin. In addition, we developed a novel plasmonic immunoassay reader using the ambient light sensor of smart phone to increase the accessibility and utility of the plasmonic immunoassay. The linear detection range of gold nanorods-based plasmonic immunoassay for myoglobin detection was 0.1–1000 ng mL−1 and the limit of detection was 0.057 ng mL−1. Myoglobin in serum samples was also analyzed by the plasmonic immunoassay. The results were significantly correlated with those of conventional enzyme-linked immunosorbent assay. The plasmonic immunoassay, coupled with smart phone-based reader, could be widely used for point-of-care testing application of acute myocardial infarction, especially in the regions with limited technological resources

Flexible, ultrathin bioelectronic materials and devices for chronically stable neural interfaces

Abstract Advanced technologies that can establish intimate, long‐lived functional interfaces with neural systems have attracted increasing interest due to their wide‐ranging applications in neuroscience, bioelectronic medicine, and the associated treatment of neurodegenerative diseases. A critical challenge of significance remains in the development of electronic platforms that offer conformal contact with soft brain tissue for the sensing or stimulation of brain activities and chronically stable operation in vivo, at scales that range from cellular‐level resolution to macroscopic areas. This review summarizes recent advances in this field, with an emphasis on the use of demonstrated concepts, constituent materials, engineered designs, and system integration to address the current challenges. The article begins with an overview of recent bioelectronic platforms with unique form factors, ranging from filamentary probes to conformal sheets and three‐dimensional frameworks for alleviating the mechanical mismatch between interface materials and neural tissues. Next, active interfaces which utilize inorganic/organic semiconductor‐enabled devices are reviewed, highlighting various working principles of recording mechanisms including capacitively and conductively coupled sensing enabled by high transistor matrices at high spatiotemporal resolution. The subsequent section presents approaches to biological integration which use active materials for multiplexed addressing, local amplification and multimodal operation with high‐channel‐count and large‐scale electronic systems in a safe fashion that provides multi‐decade stable performance in both animal models and human subjects. The advances summarized in this review will guide the future direction of this technology and provide a basis for next‐generation chronic neural interfaces with long‐lived high‐performance operation

Highly heterogeneous epitaxy of flexoelectric BaTiO3-δ membrane on Ge

The integration of complex oxides with a wide spectrum of functionalities on Si, Ge and flexible substrates is highly demanded for functional devices in information technology. We demonstrate the remote epitaxy of BaTiO3 (BTO) on Ge using a graphene intermediate layer, which forms a prototype of highly heterogeneous epitaxial systems. The Ge surface orientation dictates the outcome of remote epitaxy. Single crystalline epitaxial BTO3-δ films were grown on graphene/Ge (011), whereas graphene/Ge (001) led to textured films. The graphene plays an important role in surface passivation. The remote epitaxial deposition of BTO3-δ follows the Volmer-Weber growth mode, with the strain being partially relaxed at the very beginning of the growth. Such BTO3-δ films can be easily exfoliated and transferred to arbitrary substrates like Si and flexible polyimide. The transferred BTO3-δ films possess enhanced flexoelectric properties with a gauge factor of as high as 1127. These results not only expand the understanding of heteroepitaxy, but also open a pathway for the applications of devices based on complex oxides