Dry deposition study by using dry deposition plate and water surface sampler in Shalu, central Taiwan.

This study presents the chemical composition of dry deposition by using dry deposition plate and water surfaces sampler during daytime and nighttime sampling periods at a near highway traffic sampling site. In addition, the characterization for mass and water soluble species of total suspended particulate (TSP), PM2.5 and PM10 were also studied at this sampling site during August 22 to October 31 of 2006 around central Taiwan.

5,5,6-Fused tricycles bearing imidazole and pyrazole 6-methylidene penems as broad-spectrum inhibitors of beta-lactamases.

Beta-lactamases are serine- and metal-dependent hydrolases, produced by the bacteria as defense against beta-lactam antibiotics. Commercially available inhibitors such as clavulanic acid, sulbactam, and tazobactam, which are currently used in the hospital settings, have reduced activity against newly emerging beta-lactamases. Bacterial production of diverse beta-lactamases including class-A, class-C, and ESBLs has motivated several research groups to search for inhibitors with a broader spectrum of activity.

Structure-activity relationship of 6-methylidene penems bearing 6,5 bicyclic heterocycles as broad-spectrum beta-lactamase inhibitors: evidence for 1,4-thiazepine intermediates with C7 R stereochemistry by computational methods.

The design and synthesis of a series of 6-methylidene penems containing [6,5]-fused bicycles (thiophene, imidazole, or pyrazle-fused system) as novel class A, B, and C beta-lactamase inhibitors is described. These penems proved to be potent inhibitors of the TEM-1 (class A) and AmpC (class C) beta-lactamases and less so against the class B metallo-beta-lactamase CcrA. Their in vitro and in vivo activities in combination with piperacillin are discussed.

Simultaneous hydrogenolysis of p-nitrobenzyl esters and carbamates side-chains in the THF 1beta-carbapenem OCA-983 in biphasic media.

Deprotection of p-nitrobenzyl esters and valyl carbamates in carbapenem CL 192,276 produced the active compound OCA-983 in excellent yields. Straight chain alkanols such as 1-butanol, 1-pentanol and 1-hexanol in water at certain ratios were effective solvent systems. Alkyl acetates in water also resulted in simultaneous deprotection of PNB and PNZ side-chains albeit at slower rates.

Characterization, identification of ambient air and road dust polycyclic aromatic hydrocarbons in central Taiwan, Taichung.

The concentrations of ambient air polycyclic aromatic hydrocarbons (PAHs) were measured simultaneously in an industrial area (Taichung Industrial Park, TIP) and suburban area (Tunghai University, THU) in central Taiwan, Taichung. A total of samples were collected simultaneously at the two sites between August 2002 and March 2003. Particle-bound PAHs (p-PAHs) were collected on quartz filters and gas-phase PAHs (g-PAHs) on glass cartridges using polyurethane foam sampler, respectively.

Phenyl thiazolyl urea and carbamate derivatives as new inhibitors of bacterial cell-wall biosynthesis.

Over 50 phenyl thiazolyl urea and carbamate derivatives were synthesized for evaluation as new inhibitors of bacterial cell-wall biosynthesis. Many of them demonstrated good activity against MurA and MurB and gram-positive bacteria including MRSA, VRE and PRSP. 3,4-Difluorophenyl 5-cyanothiazolylurea (3p) with clog P of 2.

Polycyclic aromatic hydrocarbons in the ambient air of suburban and industrial regions of central Taiwan.

The concentrations of gas-phase and particle-bound polycyclic aromatic hydrocarbons (PAHs) were measured simultaneously at an industrial area (Taichung Industrial Park) and a suburban area (Tunghai University Campus) in Taichung, Taiwan. Twenty-four hours samplings for two consecutive days were performed between August and December 2002 at both sampling sites. Ambient air particle-bound PAHs were collected on quartz filters and gas-phase PAHs were collected on glass cartridges using a PUF Sampler, respectively.

2-Phenyl-5,6-dihydro-2H-thieno[3,2-c]pyrazol-3-ol derivatives as new inhibitors of bacterial cell wall biosynthesis.

Twenty-five 2-phenyl-5,6-dihydro-2H-thieno[3,2-c]pyrazol-3-ol derivatives were synthesized for evaluation as new inhibitors of bacterial cell wall biosynthesis. Many of them demonstrated good inhibitory activity against Staphylococcus aureus MurB, MurC and MurD enzymes in vitro and antimicrobial activity against gram-positive bacteria including MRSA, VRE and PRSP. However, when they were tested in the presence of 4% bovine serum albumin, the MIC values increased to greater than 128 microg/mL against PRSP.

Spirocyclopropyl beta-lactams as mechanism-based inhibitors of serine beta-lactamases. Synthesis by rhodium-catalyzed cyclopropanation of 6-diazopenicillanate sulfone.

Class A-class C mechanism-based beta-lactamase inhibitors were designed on the basis of the intermediacy of an oxycarbenium species capable of cross-linking with amino acids residues in the active site. Penams 24 and 27 were very potent against AmpC in vitro. The MIC values of 24 in combination with piperacillin against class A and class C producing organisms showed improvement over clinically used tazobactam.

Characterization of particulate, metallic elements of TSP, PM(2.5) and PM(2.5-10) aerosols at a farm sampling site in Taiwan, Taichung.

Atmospheric aerosol particles and metallic concentrations were monitored at the Experimental Farm of Tunghai University (EFTU) sampling site in this study. Total suspended particulate matter (TSP) was collected by using a PS-1 sampler at the farm-sampling site, in central Taiwan, from July 2001 to April 2002. At the same time, PM(2.

Suspended particulate variations and mass size distributions of incense burning at Tzu Yun Yen temple in Taiwan, Taichung.

Ambient suspended particulate concentrations were measured at Tzu Yun Yen temple in this study. This is characteristic place of incense burning and indoor air pollution sampling site. A universal sampler, micro-orifice uniform deposited impactor (MOUDI) sampler and dry deposition plate were used to measure particulate concentrations.

Muraymycins, novel peptidoglycan biosynthesis inhibitors: semisynthesis and SAR of their derivatives.

Sixteen muraymycin derivatives 2-17 were synthesized based on selective reactions of the primary and secondary amino groups of muraymycin C1 (1) with isocyanates and aldehydes. Disubstituted derivatives 3-9 demonstrated no activity against either MraY or MurG at View Article and Find Full Text PDF