21 research outputs found
Observation of sixfold degenerate fermions in PdSb
Three types of fermions have been extensively studied in topological quantum
materials: Dirac, Weyl, and Majorana fermions. Beyond the fundamental fermions
in high energy physics, exotic fermions are allowed in condensed matter systems
residing in three-, six- or eightfold degenerate band crossings. Here, we use
angle-resolved photoemission spectroscopy to directly visualize
three-doubly-degenerate bands in PdSb. The ultrahigh energy resolution we
are able to achieve allows for the confirmation of all the sixfold degenerate
bands at the R point, in remarkable consistency with first-principles
calculations. Moreover, we find that this sixfold degenerate crossing has
quadratic dispersion as predicted by theory. Finally, we compare sixfold
degenerate fermions with previously confirmed fermions to demonstrate the
importance of this work: our study indicates a topological fermion beyond the
constraints of high energy physics
Informetrics: theory, methods and applications
This book provides an accessible introduction to the history, theory and techniques of informetrics. Divided into 14 chapters, it develops the content system of informetrics from the theory, methods and applications; systematically analyzes the six basic laws and the theory basis of informetrics and presents quantitative analysis methods such as citation analysis and computer-aided analysis. It also discusses applications in information resource management, information and library science, science of science, scientific evaluation and the forecast field. Lastly, it describes a new development in informetrics- webometrics. Providing a comprehensive overview of the complex issues in today's environment, this book is a valuable resource for all researchers, students and practitioners in library and information science
Surgical Treatment of Refractory Chest Tumors Assisted by Cardiopulmonary Bypass
Background and objective A retrospective review of the surgical treatment of refractory chest tumors involving the heart or large vessels with cardiopulmonary bypass (CPB). Methods To summarize 11 cases of chest tumor patients who had undergone cardiopulmonary bypass surgery from January 2008 to May 2017 in our hospital, and analyze the general condition, clinical characteristics, treatment methods, postoperative hospitalization time, complications and follow-up results of all patients. Results All 11 patients were operated with cardiopulmonary bypass. Total resection of tumors in 8 cases and most of the excision in 3 cases. 1 case of left atrial metastatic leiomyosarcoma were excised in the left atrium, and then the right lung resection was performed. 1 case of left lung central lung cancer resection through the median sternum incision. 2 cases underwent pulmonary artery repair at the same time, 3 cases underwent partial pericardiectomy and 3 cases underwent pulmonary wedge resection at the same time. All the patients were effectively relieved after the operation. No death rate in hospital and 30 days after operation. 3 cases of postoperative pulmonary infection were recovered after the treatment of antibiotics. 1 case of lymphoma relapsed 6 months after surgery and died one year later. 1 case of pericardial fibrosarcoma had local recurrence and extensive metastasis at 13 months after operation, and died after 15 months. 1 case of pulmonary leiomyosarcoma were found to have local recurrence 15 months after the operation and were relieved after chemotherapy. The remaining 8 patients survived, and no obvious recurrence and distant metastasis were found in the computed tomography (CT) examination. Conclusion The CPB assisted surgical treatment can be performed for patient of refractory chest tumors involving the heart or large vessels. It can improve the surgical resection rate of refractory chest tumors, effectively alleviate the effects on respiratory and circulatory functions, and significantly prolong the survival period of these patients
Chemical Composition and Transgenerational Effects on Caenorhabditis elegans of Seasonal Fine Particulate Matter
While numerous studies have demonstrated the adverse effects of fine particulate matter (PM) on human health, little attention has been paid to its impact on offspring health. The multigenerational toxic effects on Caenorhabditis elegans (C. elegans) were investigated by acute exposure. PM2.5 and PM1 samples were collected and analysed for their chemical composition (inorganic ions, metals, OM, PAHs) in different seasons from April 2019 to January 2020 in Lin’an, China. A higher proportion of organic carbon components (34.3%, 35.9%) and PAHs (0.0144%, 0.0200%) occupied the PM2.5 and PM1 samples in winter, respectively. PM1 in summer was enriched with some metal elements (2.7%). Exposure to fine PM caused developmental slowing and increased germ cell apoptosis, as well as inducing intestinal autofluorescence and reactive oxygen species (ROS) production. PM1 caused stronger toxic effects than PM2.5. The correlation between PM component and F0 generation toxicity index was analysed. Body length, germ cell apoptosis and intestinal autofluorescence were all highly correlated with Cu, As, Pb, OC and PAHs, most strongly with PAHs. The highest correlation coefficients between ROS and each component are SO42− (R = 0.743), Cd (R = 0.816) and OC (R = 0.716). The results imply that OC, PAHs and some transition metals play an important role in the toxicity of fine PM to C. elegans, where the organic fraction may be the key toxicogenic component. The multigenerational studies show that PM toxicity can be passed from parent to offspring, and gradually returns to control levels in the F3–F4 generation with germ cell apoptosis being restored in the F4 generation. Therefore, the adverse effects of PM on reproductive damage are more profound
Reproductive toxicity and underlying mechanisms of fine particulate matter (PM2.5) on Caenorhabditis elegans in different seasons
Although numerous studies have investigated that atmospheric fine particulate matter (PM2.5) can be toxic to environmental organisms, the research on the reproductive toxicity of PM2.5 is limited, and the key toxic components and underlying mechanisms remain unknown. In this work, PM2.5 samples of four seasons in Nanjing from March 1, 2021, to February 28, 2022 were collected and the chemical components were analyzed. Caenorhabditis elegans (C. elegans) was employed to conduct the toxicological testing. The reproductive toxicity of PM2.5 to C. elegans in different seasons was evaluated by multiple reproductive endpoints. Exposure to high concentrations of PM2.5 significantly decreased the brood size and the number of fertilized eggs in utero. PM2.5 exposure also increased the number of germ cell corpses and caused abnormal expression of apoptosis-related genes (ced-9, ced-4, and ced-3), which confirmed that PM2.5 induced germline apoptosis. In addition, PM2.5 exposure significantly increased the production of reactive oxygen species (ROS) in C. elegans and the fluorescence intensity of HUS-1 protein in of transgenic strain WS1433. Meanwhile, the expression of genes related to DNA damage (cep-1, clk-2, egl-1, and hus-1) and oxidative stress (mev-1, isp-1, and gas-1) also significantly altered in C. elegans, suggesting induction of DNA damage and oxidative stress. According to Pearson correlation analyses, DNA damage and oxidative stress were significantly correlated with multiple reproductive endpoints in C. elegans. Thus, it was speculated that PM2.5 caused reproductive dysfunction and germ cell apoptosis in C. elegans may be by inducing ROS and DNA damage. In addition, heavy metals in PM2.5 were significantly correlated with multiple endpoints at physiological and biochemical, suggesting that the heavy metals might be an important contributor to the reproductive toxicity induced by PM2.5
Anti-osteosarcoma trimodal synergistic therapy using NiFe-LDH and MXene nanocomposite for enhanced biocompatibility and efficacy
Osteosarcoma is usually resistant to immunotherapy and, thus primarily relies on surgical resection and high-dosage chemotherapy. Unfortunately, less invasive or toxic therapies such as photothermal therapy (PTT) and chemodynamic therapy (CDT) generally failed to show satisfactory outcomes. Adequate multimodal therapies with proper safety profiles may provide better solutions for osteosarcoma. Herein, a simple nanocomposite that synergistically combines CDT, PTT, and chemotherapy for osteosarcoma treatment was fabricated. In this composite, small 2D NiFe-LDH flakes were processed into 3D hollow nanospheres via template methods to encapsulate 5-Fluorouracil (5-FU) with high loading capacity. The nanospheres were then adsorbed onto larger 2D Ti3C2 MXene monolayers and finally shielded by bovine serum albumin (BSA) to form 5-FU@NiFe-LDH/Ti3C2/BSA nanoplatforms (5NiTiB). Both in vitro and in vivo data demonstrated that the 5-FU induced chemotherapy, NiFe-LDH driven chemodynamic effects, and MXene-based photothermal killing collectively exhibited a synergistic “all-in-one” anti-tumor effect. 5NiTiB improved tumor suppression rate from <5% by 5-FU alone to ∼80.1%. This nanotherapeutic platform achieved higher therapeutic efficacy with a lower agent dose, thereby minimizing side effects. Moreover, the composite is simple to produce, enabling the fine-tuning of dosages to suit different requirements. Thus, the platform is versatile and efficient, with potential for further development
Recent Advances on Reactive Oxygen Species-Responsive Delivery and Diagnosis System
Reactive oxygen species (ROS) play crucial roles in biological metabolism and intercellular signaling. However, ROS level is dramatically elevated due to abnormal metabolism during multiple pathologies, including neurodegenerative diseases, diabetes, cancer, and premature aging. By taking advantage of the discrepancy of ROS levels between normal and diseased tissues, a variety of ROS-sensitive moieties or linkers have been developed to design ROS-responsive systems for the site-specific delivery of drugs and genes. In this review, we summarized the ROS-responsive chemical structures, mechanisms, and delivery systems, focusing on their current advances for precise drug/ gene delivery. In particular, ROS-responsive nanocarriers, prodrugs, and supramolecular hydrogels are summarized in terms of their application for drug/gene delivery, and common strategies to elevate or diminish cellular ROS concentrations, as well as the recent development of ROS-related imaging probes were also discussed