Objective. Vaccinium genus plants have medicinal value, of which Vaccinium arctostaphylos (Caucasian whortleberry or Qare-Qat in the local language) is the only available species in Iran. Public tendency to use herbal remedies and natural products such as synthesized nanoparticles is increasing due to the proof of the destructive side effects of chemical drugs. Nanosilver products have been effective against more than 650 microbe types. This study was aimed at assessing the possibility of green synthesis of silver nanoparticles using Vaccinium arctostaphylos aqueous extract and at evaluating its antibacterial properties, as well. Materials and Methods. In order to synthesize silver nanoparticles, different volumes of Vaccinium arctostaphylos aqueous extract (3, 5, 10, 15, and 30 ml) were assessed with different silver nitrate solution concentrations (0.5, 1, 3, 5, and 10 mM) and different reaction time durations (1, 3, 5, 10, and 20 minutes) at room temperature using a rotary shaker with a speed of 150 rpm. Ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction analysis (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) were carried out. The antibacterial activity of the aqueous extract and the synthesized nanoparticles was evaluated, as well. Results. Silver nanoparticle formation process was confirmed with XRD analysis, transmission electron microscopy (TEM), and FTIR spectroscopy. The UV-Vis spectroscopy of silver colloidal nanoparticles showed a surface plasmon resonance peak at 443 nm under optimal conditions (3 ml aqueous extract volume, 1 mM silver nitrate solution concentration, and 3 min reaction time under sunlight exposure). The reduction of silver ions to silver nanoparticles in solution was confirmed, as well. Based on X-ray diffraction analysis, the size of silver nanoparticles was in the range of 7-16 nm. TEM images showed an even distribution of silver nanoparticles, with a spherical shape. FTIR spectroscopy demonstrated the presence of different functional groups of oxygenated compounds such as carboxyl, hydroxyl, and nitrogenous groups. The antibacterial properties of the synthesized nanoparticles were confirmed. Conclusion. The synthesized nanoparticles showed more antibacterial properties against gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) than gram-negative ones (Escherichia coli and Salmonella enteritidis).
The reaction of propane-1,2-diamine (pn) and pyridine-2,6-dicarboxylic acid (pydcH2) in a 1:2 molar ratio in aqueous solution resulted in the formation of the title compound, C3H12N2 2+·2C7H4NO4·2H2O or (pnH2)(pydcH)2·2H2O. The structure contains two monoanionic deprotonated forms of pyridine-2,6-dicarboxylic acid molecules (pydcH)−, a diprotonated propane-1,2-diamine (pnH2)2+, and two water molecules. A significant π–π stacking interaction is observed between the pyridyl rings of the (pydcH)− fragments, with a face-to-face distance of 3.6194 (9) Å. In the crystal structure, a wide range of non-covalent interactions consisting of ion pairing, hydrogen bonding [of the types of O—H⋯O, N—H⋯O, N—H⋯N and C—H⋯O, with D⋯A distances in the range 2.454 (2)–3.222 (2)Å] and π–π stacking interactions [centroid–centroid distance = 3.6194 (9) Å] connect the components into a supramolecular structure.
A detailed program is proposed in the Lagrangian formalism to investigate the dynamical behavior of a theory with singular Lagrangian. This program goes on, at different levels, parallel to the Hamiltonian analysis. In particular, we introduce the notions of first class and second class Lagrangian constraints. We show each sequence of first class constraints leads to a Neother identity and consequently to a gauge transformation. We give a general formula for counting the dynamical variables in Lagrangian formalism. As the main advantage of Lagrangian approach, we show the whole procedure can also be performed covariantly. Several examples are given to make our Lagrangian approach clear.
The reaction of mercury(II) chloride dihydrate, propane-1,3-diamine and 4-hydroxypyridine-2,6-dicarboxylic acid in a 1:1:1 molar ratio in aqueous solution, resulted in the formation of the title compound, (C3H12N2)[Hg(C7H3NO5)Cl(H2O)]2·4H2O or (pnH2)[Hg(hypydc)Cl(H2O)]2·4H2O (where pn is propane-1,3-diamine and hypydcH2 is 4-hydroxypyridine-2,6-dicarboxylic acid). The metal atom is coordinated by one chloride group, one water molecule cis to the chloride ligand and one (hypydc)2− ligand. The coordinated water molecule is almost perpendicular to the plane of the aromatic ring of (hypydc)2−. The geometry of the resulting HgClNO3 coordination can be described as distorted square-pyramidal. This structure also contains propane-1,3-diammonium (site symmetry 2) as a counter-ion and four uncoordinated water molecules. There is a wide range of non-covalent interactions consisting of hydrogen bonding [of the types O—H⋯O, N—H⋯O and C—H⋯O, with D⋯A ranging from 2.548 (5) to 3.393 (6) Å] and ion pairing.
The title polymeric compound, {[Cd2(C7H3NO5)2(H2O)4]·4H2O}n or {[Cd2(hypydc)2(H2O)4]·4H2O}n (where hypydcH2 is 4-hydroxypyridine-2,6-dicarboxylic acid), was synthesized by the reaction of cadmium(II) nitrate hexahydrate with 4-hydroxypyridine-2,6-dicarboxylic acid and propane-1,3-diamine, in a 1:2:2 molar ratio in aqueous solution. The compound is a seven-coordinate binuclear polymeric complex with distorted pentagonal bipyramidal geometry around CdII [Cd—O = 2.247 (4)–2.474 (3) Å]. In the binuclear monomeric units, the central atoms join together by O atoms of two bridging tridentate (hypydc)2− ligands, and the polymer propagates via two bridging water molecules that link each CdII centre of one monomer to the adjacent neighbour. Propane-1,3-diamine (pn) does not appear in the product but plays a role as a base. Intermolecular O—H⋯O and C—H⋯O hydrogen bonds, and π–π stacking interactions, with distances of 3.725 (3) and 3.766 (3) Å, connect the various components.
The reaction of nickel(II) nitrate hexahydrate, propane-1,2-diamine and pyridine-2,6-dicarboxylic acid in a 1:2:2 molar ratio in aqueous solution resulted in the formation of the title compound, (C3H12N2)[Ni(C7H3NO4)2]·4H2O or (p-1,2-daH2)[Ni(pydc)2]·4H2O (where p-1,2-da is propane-1,2-diamine and pydcH2 is pyridine-2,6-dicarboxylic acid). The geometry of the resulting NiN2O4 coordination can be described as distorted octahedral. Considerable C=O⋯π stacking interactions are observed between the carboxylate C=O groups and the pyridine rings of the (pydc)2− fragments, with O⋯π distances of 3.1563 (12) and 3.2523 (12) Å and C=O⋯π angles of 95.14 (8) and 94.64 (8)°. In the crystal structure, a wide range of non-covalent interactions, consisting of hydrogen bonding [O—H⋯O, N—H⋯O and C—H⋯O, with D⋯A distances ranging from 2.712 (2) to 3.484 (2) Å], ion pairing, π–π [centroid-to-centroid distance = 3.4825 (8) Å] and C=O⋯π stacking, connect the various components to form a supramolecular structure.
Forest road pavement needs an evaluation methodology based on a comprehensive assessment of road conditions. This research was conducted to evaluate the performance of a method for rating the surface condition of forest roads and eventually to adapt the method to the situation prevailing in a forest road network. The rating method selected as the basis for this experiment was the pavement condition index (PCI) developed by the U.S. Army Corps of Engineers. A 53 km of forest roads were selected contained the most influential factors and conditions variability. Eventually, 201 road segments were delineated between 150-300 m in length. Within the given segments, sample plots were set 20 m in length consecutively. It was concluded that the panel scores for distress and surface condition of sample unit and section differed from forest road pavement condition index (FRPCI) and PCI. Linear regression was used to derive equations between distress and PCI score to determine effective FRPCI parameters that provide a numerical rating for the condition of road segments within the road network, where 0 worlds are the worst possible condition, and 100 is the best possible condition best. Also, regression analysis showed the FRPCI model with a 0.87 correlation for the total of the road is a performance index used for the first time in forest roads. This study showed a range of FRPCI from 7.8 to 96.3, different from PCI and URCI ratings (0.85-45 and 1.2-53). The FRPCI index helps forest managers in road maintenance, harvesting, and planning to use road information.
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