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Cyclodextrins are a type of natural materials that can be used in the pharmaceutical industry. Cyclodextrins are safe, biodegradable, with the multifunctional property as they can encapsulate both hydrophilic and hydrophobic drugs. Additionally, they can overcome challenges associated with drug toxicity and enhancing the solubility of the insoluble drugs; thus, cyclodextrins are effective carriers in loading tiny molecules. Moreover, the synthesis of nanosponges (NPs) systems can enhance the drug encapsulation in cyclodextrin cavities to control the rate of drug released. Cyclodextrin can contain the drug molecules to form a clathrate; cyclodextrin-based NPs can maintain a high loading capacity of various small molecules for drug delivery. This review presents a general overview of the current research progress and the applications of cyclodextrin-based NPs for drug delivery in the past two decades. [ABSTRACT FROM AUTHOR]

Given the conflicts over the proposed formation mechanisms of Xiashu loess, the question of the provenance of sediments comprising the Xiashu loess in the Yangtze River Delta has not been satisfactorily resolved. In this study, the provenance of aeolian sediments of the Yangtze River Delta, China was examined by applying the detrial zircon U-Pb dating technique, Sr-Nd isotopic and trace element compositional analysis. U-Pb dating analysis was conducted on the Xiashu loess at three locations over the Yangtze River Delta, including Huangnishan (HNS) hill, Shengshan (SS) island and the Xuancheng (XC) area. The Xiashu loess and the sediments of the Yangtze River Valley share considerable similarity in their zircon U-Pb age spectra with the same main age peak and comparable age distribution. By contrast, significant differences in the age spectra, exist between the Xiashu loess and loess deposits of Chinese Loess Plateau (CLP). Coarse grains of the Yangtze River Delta loess may have a proximal material source identical to the sediments from the Yangtze River valley. Sr-Nd isotopic values of the Xiashu loess match those from the northern margin of the Tibetan Plateau. Rare earth element ratios independent of grain size illustrate that the values from loess of the Yangtze River Delta mostly overlap with those of CLP loess. This feature implies that loess from the Yangtze River Delta has a dominant source of distant material similar as the CLP loess. As such, we conclude that multi-proxy analysis of sediments can shed new light on tracing the provenance of aeolian loess in the Yangtze River Delta. [ABSTRACT FROM AUTHOR]

Increasing interest in recent years has focused on vermicular red clay (VRC) in southern China due to its controversial sedimentary environment and provenance. Grain size is a useful way to determine sedimentary environment and provenance. Fisher Linear Discriminant Analysis (LDA) is a common and widely used method for multivariate statistical analysis. Based on a proper training sample set, the LDA can be used to discuss the sediment provenance. In this study, grain size data for 77 Malan loess samples and 41 floodplain deposit samples were used as a training sample set to deduce a Fisher linear discriminant function. Then, 299 VRC samples from 6 Quaternary red clay profiles were analyzed using the discriminant function. Grain size parameters and microscopic images of quartz grains separated from the VRC were evaluated in detail to determine the VRC sedimentary environment in south China. The results show that VRC profiles can be classified into two regions: the Chiang-nan Hilly Region and Wuyi Mountains Region. The VRC samples in the Chiang-nan Hilly Region originated from eolian dust deposits. This VRC is characterized by a higher content of fine particles (<20 μm) and lower average transport kinetic energy than loess in a C-M plot. The quartz grain sizes and microscope images of this VRC suggest that it could be a polyphyletic mixture of far-sourced and near-sourced eolian deposits. The far-sourced eolian deposits share similar provenance with Xiashu loess and were transported by the East Asian winter monsoon. The near-sourced eolian deposits were dust emitted from the adjacent floodplain. In the Wuyi Mountains Region, the rugged topography weakened the dustfall and strengthened the reconstructive effect of hydrodynamic forces during the Quaternary glacial periods. The VRC in this region was reworked strongly by water and retained typical hydraulic characteristics no matter the source. [ABSTRACT FROM AUTHOR]

Background: Endoscopic thyroidectomy has been known to surgeons for only 20 years. Related studies still are needed to make up for the deficiency of clinical experience. Research on the learning curve for the endoscopic thyroidectomy could be the method for investigating the operation experience.Methods: This retrospective study investigated 300 consecutive patients who underwent endoscopic thyroidectomy by a single endoscopist during the past 7 years. The study population was equally divided into 10 groups chronologically. Pearson's chi-square test and one-way analysis of variance were used to compare differences in the demographic data, operative time, operation score system, and follow-up data.Results: The mean operative time was 98.07 min. The mean operation score was 6.00, and the rate of conversion to open surgery was 3.7%. There were no differences in demographic data or complications among the 10 groups. Subcutaneous edema occurred in five cases and transient recurrent laryngeal nerve palsy in five cases. There were significant differences in the mean operative time (p < 0.01) and the mean operation score (p < 0.01) among the 10 groups. Comparison of two neighboring groups showed differences in both operative time (p < 0.05) and operation score (p < 0.01) between groups 2 and 3 and in operation score between groups 5 and 6 (p < 0.05).Conclusions: The first 60 cases constitute the early stage of the learning curve for endoscopic thyroidectomy. The proficiency and stability of the operation reach the advanced level after 150 cases. [ABSTRACT FROM AUTHOR]