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To assess the water quality characteristics of different types of water sources and find their differences in water quality, quality of drinking water sources including reservoirs, rivers, springs, and groundwater in the lower reaches of Yellow River has been seasonally investigated during 2019 and 2021. The water quality varied greatly among different water bodies, and the four types of water bodies were divided into surface (reservoirs and rivers) and groundwater (groundwater and springs) based on the water quality characteristics. Five principal components were extracted, together explaining 84% of all the variance information by log-transformed principal component analysis, which represented that anions, formation potential of disinfection by-products precursors, nutrients, and phytoplankton biomass affected the water quality of these waterbodies. The matter sources of surface water and groundwater were quite different, with dominant by organic compounds and inorganic matters, respectively. However, the similar humus carbon-to-nitrogen ratio (HS-C/N) values indicated that the organic matter in groundwater is affected to a certain extent by the replenishing surface water. In the aspect of inorganic ions, these waterbodies were more affected by Na+–Cl−–SO42− in the wet season, while Ca2+–HCO3−–CO32− in the dry season. Gibbs diagram suggested that the anions and cations were mainly contributed by atmospheric precipitation for the surface water, while they were mainly derived from rock weathering for the groundwater. It is hoped that this study will help to evaluate the pollution risk and the feasibility of long-term implementation of artificial source remediation projects. [ABSTRACT FROM AUTHOR]

C2 laminar screws have become an increasingly used alternative method to C2 pedicle screw fixation. However, the outcome of this technique has not been thoroughly investigated. A total of 35 cases with upper cervical spinal instability undergoing C2 laminar screw fixation were reviewed. All cases had symptoms of atlantoaxial instability, such as craniocervical junction pain, and were fixed with the Vertex cervical internal fixation system. A total of 68 screws were placed and hybrid constructs (a C2 translaminar screw combined with a C2 pars screw) were incorporated in two patients. In this series, there were no intraoperative complications and no cases of neurological worsening or vascular injury from hardware placement. Computed tomographic scans demonstrated a partial dorsal laminar breach in ten patients. None of these resulted in neurological symptoms. None of the patients was found to have a breach of the ventral laminar cortex. All the C2 laminar screws fixations were performed successfully. There was no instability seen on the films with no evidence of hardware failure or screw loosening during the follow-up period in all patients. In conclusion, C2 laminar screw technique is straightforward and easily adopted; it can efficiently and reliably restore upper cervical stability. It is an alternative method to C2 pedicle screw fixation, especially in patients with unilateral occlusion of vertebral artery and pedicle deformity of C2. [ABSTRACT FROM AUTHOR]

Abstract  A novel injectable in situ cross-linked hydrogel was prepared from α,β-poly(N-hydroxyethyl)-dl-aspartamide (PHEA), which had excellent biocompatibility and biodegradability. PHEA was modified by acryloyl chloride (AC) via the reaction between hydroxyl groups and acryl groups to introduce reactable double bonds into the chain. Two macromers with different degrees of derivatization were prepared. Through NMR and FT-IR characterizations, the structures of the polymers were proposed. Hydrogels were prepared by covalent cross-linking between double bonds with a transition from liquid to gel at body temperature. The effect factors on gelation time, swelling ratio and gel content were investigated in detail. It was found that the grafting ratios of AC, concentrations of macromer and initiator had great influence on the gelation time. And it could be adjusted to meet the requirements of an injectable material. [ABSTRACT FROM AUTHOR]

Simulated Annealing (SA) is a popular global minimization method. Two weaknesses are associated with standard SA: firstly, the search process is memory-less and therefore can not avoid revisiting regions that are less likely to contain global minimum: and secondly the randomness in generating a new trial does not utilize the information gained during the search and therefore, the search can not be guided to more promising regions. In this paper, we present the Learning-Enhanced Simulated Annealing (LESA) method to overcome these two difficulties. It adds a Knowledge Base (KB) trial generator, which is combined with the usual SA trial generator to form the new trial for a given temperature. LESA does not require any domain knowledge and, instead, initializes its knowledge base during a "burn-in" phase using random samples of the search space, and, following that, updates the knowledge base at each iteration. This method was applied to 9 standard test functions and a clinical application of lung nodule registration, resulting in superior performance compared to SA. For the 9 test functions, the performance of LESA was significantly better than SA in 8 functions and comparable in 1 function. For the lung nodule registration application, the residual error of LESA was significantly smaller than that produced by a recently published SA system, and the convergence time was significantly faster (9.3 ± 3.2 times). We also give a proof of LESA's ergodicity, and discuss the conditions under which LESA has a higher probability of converging to the true global minimum compared to SA at infinite annealing time. [ABSTRACT FROM AUTHOR]

Presents a study which examines the geothermal evolution of basins. Application of thermoluminescence; Reference to the use of the fission track analysis; Complexity of the change of the track ages.