409 research outputs found

    Smart Drug Delivery Strategies Based on Porous Nanostructure Materials

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    The control of drug delivery can have a great effect on its efficacy. An optimum concentration range of drugs can play a significant role in the human body, and it can cause harm to humans when it exceeds the range of the drug concentration. Recently, a variety of drug deliveries and their targeted systems have been studied to minimize drug loss and maximize the amount of drug accumulated in the required area, thus increasing drug bioavailability. In addition, we should especially consider the prevention of its harmful side-effects in the human body. Innovative drug delivery systems based on biodegradable, natural or synthetic polymers, micro- or nano-particles, lipoproteins, micelles, TiO2 nanotube arrays (TNTs), nanoporous anodic aluminum oxide (AAO), and so on were developed, which combined magnetic targeting and stimulus-responsive in drug delivery systems. The composition of delivery carriers and the stimulus-responsive elements proved stimulus-responsive drug release as a smart drug delivery system

    Breakdown Characteristics of Varistor Ceramics

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    Breakdown characteristics are of great importance for varistor ceramics, which largely depend on Schottky barriers at grain boundaries. In order to enhance breakdown performance for meeting the requirement of device miniaturization, different doping methods are introduced to not only restrict grain size from additional phase but also manipulate defect structure of Schottky barrier at grain boundaries from substitution. Distribution of barriers is another key point affecting breakdown characteristics in varistor ceramics. Dimensional effect, which is detected in not only ZnO ceramics but also CaCu3Ti4O12 ceramics, is practically and theoretically found to be closely correlated with uniformity of grains. As a result, breakdown characteristics of varistors are dominated by combination effect of single barrier performance and spatial barrier distribution. In this chapter, enhanced breakdown field in CaxSr1−xCu3Ti4O12 ceramics, in situ synthesized CaCu3Ti4O12-CuAl2O4 ceramics, and CaCu3Ti4O12-Y2/3Cu3Ti4O12 composite ceramics are investigated from the aspect of Schottky barriers at grain boundaries. In addition, dimensional effect is found in both ZnO and CaCu3Ti4O12 ceramics, which are investigated from grain size distribution through theoretical and experimental analysis

    Current Tissue Engineering Approaches for Cartilage Regeneration

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    Cartilage is one of the critical tissues existed in human and animal bodies. Unlike most tissues, cartilage does not have blood vessels, nerves, and lymphatics. Most cartilage tissues in vivo are subjected to large mechanical loads, and its principal function is to provide a smooth and lubricated surface to facilitate the transmission of mechanical loads with a low frictional coefficient. As a result, cartilage tissues are easily injured. Cartilage defects are frequently caused by trauma, aging, congenital diseases (osteochondritis), and many more factors such as endocrine pathologies and cancer. The damaged cartilage has a limited capacity for healing and repairing. Thus, restoration of normal structure and function to damaged cartilage is one of the most challenging areas in orthopedic research and sports medicine. Tissue engineering provides a prospective alternative strategy by seeding chondrogenic cells into or onto biocompatible scaffolds to produce engineer cartilage for damaged cartilage repair. This book chapter has summarized recent progress in cartilage tissue engineering including stem cells, growth factors, bioactive molecules, and biomaterial scaffolds used for cartilage regeneration. The procedures for some new approaches have also been described

    Advanced Progress of Green Textile with Special Wettability

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    We introduced the preparation mechanism of biomimetic superhydrophobic surfaces and the development of hydrophobic finishing chemicals. The research process of multi-functional green textile with special wettability in the last 10 years was systematically reviewed. The preparation technologies and applications in double-superhydrophobic, asymmetric superhydrophobic/superhydrophilic janus surface, patterned/ stimulated responsive surface were discussed. The prospective works were emphasised in this review, including self-cleaning, oil/water separation, durable mechanical surfaces, patterning, self-healing, one-way transportation, especially in some emerging fields such as smart response, wearable electronics, energy- harvesting. The summary and outlook of superhydrophobic and multi-funtional textile were also demonstrated at last

    Electrospun Nanocomposite Fibrous Membranes for Sustainable Face Mask Based on Triboelectric Nanogenerator with High Air Filtration Efficiency

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    Air pollution caused by the rapid development of industry has always been a great issue to the environment and human being’s health. However, the efficient and persistent filtration to PM0.3 remains a great challenge. Herein, a self-powered filter with micro–nano composite structure composed of polybutanediol succinate (PBS) nanofiber membrane and polyacrylonitrile (PAN) nanofiber/polystyrene (PS) microfiber hybrid mats was prepared by electrospinning. The balance between pressure drop and filtration efficiency was achieved through the combination of PAN and PS. In addition, an arched TENG structure was created using the PAN nanofiber/PS microfiber composite mat and PBS fiber membrane. Driven by respiration, the two fiber membranes with large difference in electronegativity achieved contact friction charging cycles. The open-circuit voltage of the triboelectric nanogenerator (TENG) can reach to about 8 V, and thus the high filtration efficiency for particles was achieved by the electrostatic capturing. After contact charging, the filtration efficiency of the fiber membrane for PM0.3 can reach more than 98% in harsh environments with a PM2.5 mass concentration of 23,000 µg/m3, and the pressure drop is about 50 Pa, which doesn’t affect people’s normal breathing. Meanwhile, the TENG can realize self-powered supply by continuously contacting and separating the fiber membrane driven by respiration, which can ensure the long-term stability of filtration efficiency. The filter mask can maintain a high filtration efficiency (99.4%) of PM0.3 for 48 consecutive hours in daily environments

    Identification of a diagnostic model and molecular subtypes of major depressive disorder based on endoplasmic reticulum stress-related genes

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    SubjectMajor depressive disorder (MDD) negatively affects patients’ behaviours and daily lives. Due to the high heterogeneity and complex pathological features of MDD, its diagnosis remains challenging. Evidence suggests that endoplasmic reticulum stress (ERS) is involved in the pathogenesis of MDD; however, relevant diagnostic markers have not been well studied. This study aimed to screen for ERS genes with potential diagnostic value in MDD.MethodsGene expression data on MDD samples were downloaded from the GEO database, and ERS-related genes were obtained from the GeneCards and MSigDB databases. Differentially expressed genes (DEGs) in MDD patients and healthy subjects were identified and then integrated with ERS genes. ERS diagnostic model and nomogram were developed based on biomarkers screened using the LASSO method. The diagnostic performance of this model was evaluated. ERS-associated subtypes were identified. CIBERSORT and GSEA were used to explore the differences between the different subtypes. Finally, WGCNA was performed to identify hub genes related to the subtypes.ResultsA diagnostic model was developed based on seven ERS genes: KCNE1, PDIA4, STAU1, TMED4, MGST1, RCN1, and SHC1. The validation analysis showed that this model had a good diagnostic performance. KCNE1 expression was positively correlated with M0 macrophages and negatively correlated with resting CD4+ memory T cells. Two subtypes (SubA and SubB) were identified, and these two subtypes showed different ER score. The SubB group showed higher immune infiltration than the SubA group. Finally, NCF4, NCF2, CSF3R, and FPR2 were identified as hub genes associated with ERS molecular subtypes.ConclusionOur current study provides novel diagnostic biomarkers for MDD from an ERS perspective, and these findings further facilitate the use of precision medicine in MDD

    A Forward-Secure Certificate-based Signature Scheme

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    Cryptographic computations are often carried out on insecure devices for which the threat of key exposure raises a serious concern. In an effort to address the key exposure problem, the notion of forward security was first presented by Günther in 1990. In a forward-secure scheme, secret keys are updated at regular periods of time; exposure of the secret key corresponding to a given time period does not enable an adversary to ‘break’ the scheme for any prior time period. In this paper, we first introduce forward security into certificate-based cryptography and define the security model of forward-secure certificate-based signatures (CBSs). Then we propose a forward-secure CBS scheme, which is shown to be secure against adaptive chosen message attacks under the computational Diffie–Hellman assumption in the random oracle model. Our result can be viewed as the first step toward solving the key exposure problem in CBSs and thus improving the security of the whole system
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