Implementation of Numerical Mesostructure Concrete Material Models: A Dot Matrix Method.

We develop a dot matrix method (DMM) using the principles of computational geometry to place aggregates into matrices for the construction of mesolevel concrete models efficiently and rapidly. The basic idea of the approach is to transform overlap detection between polygons (or polyhedrons) into checking the possibility of any intersection between the point sets within a trial placement aggregate and the already placed ones in mortar. Through the arithmetic operation of integer point sets, the efficiency of the underlying algorithm in the dot matrix method is higher. Our parking algorithm holds several advantages comparing with the conventional placement issues. First, it is suitable for arbitrary-shape aggregate particles. Second, it only needs two sets for examining if the overlap between a trial placement aggregate and the already placed ones. Third, it accurately places aggregates according to aggregate grading curves, by order of reduction, led to more efficiently reducing aggregate placement time. The present method is independent of the size of aggregate particles. Combing with 3D laser scanning technology, the present method can also be used to create mesostructure concrete models conveniently and flexibly. Several examples show that DDM is a robust and valid method to construct mesostructure concrete models.

Synthesis and Antifungal Activities of Drimane-Amide Derivatives from Sclareol.

AIM AND OBJECTIVE: Plant diseases are caused by fungal pathogens lead to severe economic losses in many agriculture crops. And the increasing resistance of many fungi to commonly used antifungal agents necessitates the discovery and development of new fungicides. So this study was focused on synthesizing novel skeleton compounds to effectively control plant diseases. MATERIALS AND METHODS: A series of drimane-amide derivatives were designed, synthesized by aminolysis reaction of amine with intermediate sclareolide which was prepared from sclareol. The structures of all the synthesized compounds were confirmed using 1H NMR, 13C NMR, and HRMS (ESI) spectroscopic data. Their in vitro antifungal activity were preliminarily evaluated by using the mycelium growth rate method against five phytopathogenic fungi: Botrytis cinerea, Glomerella cingulata, Alternaria alternate, Alternaria brassicae, and Fusarium graminearum. RESULTS: 23 target compounds were successfully obtained in yields of 52-95%. Compounds A2 and A3 displayed favorable inhibitory potency against B. cinerea, G. cingulata and A. brassicae with IC50 values ranging from 3.18 to 10.48 µg/mL. These two compounds displayed higher fungicidal activity than sclareol against all the tested phytopathogenic fungi, and were more effective than the positive control thiabendazole against A. alternate and A. brassicae. The structure-activity relationship studies of compounds A1-10 indicated that both the position and type of substituent on the phenyl ring had significant effects on antifungal activity. CONCLUSION: The drimane-amide derivatives A2 and A3 were the most promising derivatives and should be selected as new templates for the potential antifungal agents.

Synthesis and Biological Evaluation of Hexahydropyrrolo[2,3-b]Indole Derivatives as Fungicides against Phytopathogenic Fungi.

Eighteen hexahydropyrrolo[2,3-b]indole derivatives were synthesized and evaluated their in vitro antifungal activities against five phytopathogenic fungal strains through the mycelium growth rate method. Analysis of the structure-activity relationship on these synthesized compounds revealed that the introduction of benzyl or substituted benzyl group at the C-3a or N-8 position of the pyrroloindoline scaffold conferred higher antifungal activity against all tested phytopathogenic fungi than compound 4a (both C-3a and N-8 positions are prenyl groups). Especially, compound 4r, among all the tested compounds, showed the most effective antifungal activity against Fusarium coeruleum, and Fusarium graminearum with IC50 values of 4.61 and 5.02 µg/mL, respectively. Moreover, all synthesized compounds 4a-4r displayed higher activities against Curvularia lunata than the positive control thiabendazole, a commercial agricultural fungicide.

Synthesis and antifungal activity of ethers, alcohols, and iodohydrin derivatives of sclareol against phytopathogenic fungi in vitro.

This study synthesized 20 sclareol derivatives. The antifungal activities of these derivatives were evaluated in vitro against five phytopathogenic fungi using the mycelium growth rate method. Among all the tested compounds, compound 16 with one iodine atom and three hydroxyl groups displayed higher fungicidal activities against all the tested phytopathogenic fungi than precursor sclareol. Compound 16 also showed more pronounced antifungal activities against Curvularia lunata (IC50=12.09 µg/mL) and Alternaria brassicae (IC50=14.47 µg/mL) than the positive control, a commercial agricultural fungicide thiabendazole.

A novel fluorogenic substrate for dinuclear Zn(II)-containing metallo-ß-lactamases.

In an effort to prepare a fluorogenic substrate to be used in activity assays with metallo-ß-lactamases, (6R,7R)-8-oxo-7-(2-oxo-2H-chromene-3-carboxamido)-3-((4-(2-oxo-2H-chromene-3-carboxamido)-phenylthio)methyl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid (CA) was synthesized and characterized. CA exhibited a fluorescence quantum yield (φ) of 0.0059, two fluorescence lifetimes of 3.63×10(-10) and 5.38×10(-9)s, and fluorescence intensity that is concentration-dependent. Steady-state kinetic assays revealed that CA is a substrate for metallo-ß-lactamases (MßLs) L1 and CcrA, exhibiting Km and kcat values of 18µM and 5s(-1) and 11µM and 17s(-1), respectively.