An investigation of the pullout behaviors of tire strips embedded in tire-derived aggregate reinforced sand.

The recycling of scrap tires has become an important issue in the area of environmental protection in the past 20 years. In recent years, tire strips and tire-derived aggregates (TDA) have been used in geotechnical engineering projects. Both reinforcement methods are proved available to improve the horizontal resistance of stabilized structures. This study reported a new method which combined tire strips and TDA utilization in order to investigate if such combinations could further improve the stability of retaining structures. The shear properties of TDA reinforced sand with different tire content levels (0%, 10%, 20%, and 30%) were measured using direct shear tests. The pullout behaviors of tire strips with and without transverse ribs embedded in pure sand/TDA reinforced materials were then compared. Based on the obtained results, a new calculation method was proposed for the estimation of the peak pullout resistance of tire strips embedded in TDA-reinforced sand, with the interference of transverse ribs and different tire content levels of the TDA-reinforced sand taken into consideration. The test results revealed that a tire content level of 20% was the optimal proportion of TDA-reinforced sand. Meanwhile, the model tests proved that the end resistance provided by transverse ribs could largely enhance the ultimate pullout capacity of soil structures. Therefore, it was concluded that the proposed methods were feasible in scrap tire recycling projects, and the test results and proposed calculation method could potentially provide important references for the future designs and construction of tire strip stabilized retaining walls.

Computational Analysis of Naturally Occurring Aristolochic Acid Analogues and Their Biological Sources.

Aristolochic acids are known for nephrotoxicity, and implicated in multiple cancer types such as hepatocellular carcinomas demonstrated by recent studies. Natural products that are analogues to aristolochic acids have been constantly isolated from organisms; a larger chemical space of these compounds and a wider coverage of biological sources should be determined in consideration of the potential hazard of aristolochic acid analogues and the wide distribution of their biological sources in the nature. Therefore, we carried out an in silico research of naturally occurring aristolochic acid analogues and their biological sources, as a supplement to existing studies. The result shows a chemical space of 238 naturally occurring aristolochic acid analogues that are present in 175 species of biological sources including 44 traditional medicines. With the computational estimation for toxicity and the implication in hazard assessment of a biological source with the presence of aristolochic acid analogues, we propose that additional awareness should be raised to the public for avoidance of toxic species, especially those that are used as herbal medicines and easily accessible.

NPBS database: a chemical data resource with relational data between natural products and biological sources.

NPBS (Natural Products & Biological Sources) database is a chemical data resource with relational data between natural products and biological sources, manually curated from literatures of natural product researches. The relational data link a specific species and all the natural products derived from it and contrarily link a specific natural product and all the biological sources. The biological sources cover diverse species of plant, bacterial, fungal and marine organisms; the natural molecules have proper chemical structure data and computable molecular properties and all the relational data have corresponding references. NPBS database provides a wider choice of biological sources and can be used for dereplication to prevent re-isolation and re-characterization of already known natural products. Database URL: http://www.organchem.csdb.cn/scdb/NPBS.

Virtual Screening for Reactive Natural Products and Their Probable Artifacts of Solvolysis and Oxidation.

Chemically unstable natural products are prone to show their reactivity in the procedures of extraction, purification, or identification and turn into contaminants as so-called "artifacts". However, identification of artifacts requires considerable investments in technical equipment, time, and human resources. For revealing these reactive natural products and their artifacts by computational approaches, we set up a virtual screening system to seek cases in a biochemical database. The screening system is based on deep learning models of predicting the two main classifications of conversion reactions from natural products to artifacts, namely solvolysis and oxidation. A set of result data was reviewed for checking validity of the screening system, and we screened out a batch of reactive natural products and their probable artifacts. This work provides some insights into the formations of natural product artifacts, and the result data may act as warnings regarding the improper handling of biological matrixes in multicomponent extraction.

Neural machine translation of chemical nomenclature between English and Chinese.

Machine translation of chemical nomenclature has considerable application prospect in chemical text data processing between languages. However, rule based machine translation tools have to face significant complication in rule sets building, especially in translation of chemical names between English and Chinese, which are the two most used languages of chemical nomenclature in the world. We applied two types of neural networks in the task of chemical nomenclature translation between English and Chinese, and made a comparison with an existing rule based machine translation tool. The result shows that deep learning based approaches have a great chance to precede rule based translation tools in machine translation of chemical nomenclature between English and Chinese.

[Polymorphism of c-Ha-ras 3'VNTR in hydatidiform mole and its relationship with the development of postmolar tumor].

OBJECTIVE: To study the polymorphism of c-Ha-ras 3' variable number of tandem repeat (VNTR) and its relationship with development of postmolar tumor. METHODS: The cases of hydatidiform mole (HM) were retrospectively analyzed by amplified fragment length polymorphism-polyacrylamide gel electrophoresis. The DNA origin of HM was determined by comparison with the parents' DNA amplified results. RESULTS: Among the samples from 15 cases, DNA from only paternal origin was found in 2 cases. DNA from both parents was in 13 cases, and of these 13 cases, 2 were found to be had balanced DNA origin, 11 had more DNA form paternal origin than DNA from maternal origin. CONCLUSION: The HM which has DNA from both parents origin and predominantly from paternal origin developed to postmolar tumor more frequently.