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This study evaluated the impact of storing chicken manure on the degradation of enrofloxacin (ENR) and ciprofloxacin (CIP), and on the survival of CIP-resistant Enterobacteriaceae. At 24 d of age, half of 8900 chickens received ENR for 5 d. After the animals departed, their manure was stored in two heaps for 63 d. Enterobacteriaceae were cultured on media containing 0 to 32 mg L?1 of CIP. A total of 320 isolates were fingerprinted using enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) to evaluate community structure. Initial concentrations of ENR and CIP in the heap were 22 and 1.8 mg kg?1, respectively. Seventy-three percent of the two fluoroquinolones were eliminated during storage. The administration of ENR led to a 5.1 log??? decrease in Enterobacteriaceae concentrations and emergence of CIP-resistant bacteria, which became dominant in the feces. concentrations decreased 1.2 to 2.3 log??? 2 d after the heaps were made and continued to decline during storage. No resistant were found by Day 63. The highest CIP minimum inhibitory concentration (MIC) values observed among isolates of and of both and sp. were 128 and 4 mg L?1, respectively. The dominant ERIC-PCR profiles changed over time. There was no relationship between genotype and resistance-isolated strains to CIP. Storing chicken manure in heaps appeared to be an effective way of limiting the entrance of CIP-resistant E. coli into the environment but did not prevent the dissemination of fluoroquinolones after land spreading.  相似文献   
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Environmental Science and Pollution Research - Malaria is a dangerous disease affecting millions around the globe. Biosynthesized nanoparticles are used against a variety of diseases including...  相似文献   
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This study deals with atmospheres generated by coal burning, in order to verify whether aerosols collected in the environment of a thermal coal power plant produce a mutagenic effect. Biological tests were conducted (Ames' test) in order to study the mutagenic effects and to assess and compare risks. First, a chemical treatment was applied to the aerosols in order to separate mineral and organic fractions (hydrophile, aromatic, and aliphatic). Polyaromatic hydrocarbons were then evaluated and the mutagenic activity of every fraction was determined. The results obtained were compared by estimating the “mutagenic effect speed” parameters of these various fractions.  相似文献   
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Three hundred and twenty-two percutaneous umbilical blood samplings were performed over 4 years in our prenatal diagnostic centre. A 3·5 MHz sector ultrasound transducer was used to guide a 22·5-gauge needle under local anaesthesia. Sampling was performed fcir rapid fetal karyotyping (within 72 h) in 120 cases, for diagnosis of fetal toxoplasmosis in 133 cases, for determination of the severity of Rh immunization in 15 cases, and for diagnosis of congenital rubella in 4 cases. Pure fetal blood was obtained in 98·7 per cent of the cases after two attempts. The approach to the cord was either transamniotic or trans-piacental. Puncturing was preferentially done at the placental insertion of the cord (72·2 per cent of the cases) and the mean blood sample volume was 3·5 ml. The rate of fetal death in utero was 1 9 per cent, including two cases of amnionitis, one trisomy 18, and one severe bradycardia. The failures were due to sampling at an early stage of pregnancy (before gestation week 18), to maternal obesity, oligohydramnios, and the inexperience of the operator.  相似文献   
5.
The Central Valley of California contains critical habitat for many aquatic and terrestrial biological resources. The purpose of this R-EMAP project was to assess the effects from a highly modified agriculturally dominated landuse area on the aquatic resources of the lower portion of the Central Valley watersheds. The study area is 24,346 mi2 and comprises the Sacramento Valley and San Joaquin Valley watersheds to the 1,000 ft. elevation contour. Populations of interest are man-made conveyances and wadeable natural streams. There are 40,756 miles of streams and constructed conveyances within the Central Valley as designated by RF3 database. Sample sites were selected to represent 14,399 miles of streams and sloughs, and 16,697 miles of constructed conveyances.  相似文献   
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