Objective To investigate the radioactivity level of natural rocks in Lhasa in order to obtain the radionuclide contents and availiability of the rock.Methods Radiation monitoring and sampling were carried out in the natural rock mining area in Lhasa,and the contents of radionuclides in the samples were analyzed.Both internal and external exposure indexes were calculated,and the rocks were classified according to the relevant national standards on building materials.Results The average specific activity of 40K,226Ra,232Th and 238U in the rock samples were 912,59.0,77.1,and 64.4 Bq/kg,respectively.Internal and external exposure indexes were both less than 1.Conclusions The radioactivity level in natural rocks in Lhasa were lower than the national levels.The natural rocks could be used as main building materials and Class A decoration materials.

Objective To investigate transmission routes of healthcare-associated infection(HAI)caused by methi-cillin-resistant Staphylococcus aureus (MRSA),and make effective measures for preventing and controlling the oc-currence and epidemic of HAI caused by multidrug-resistance bacteria.Methods From February 24 to March 29, 2012,12 MRSA-infected patients were performed epidemiological study,these patients underwent bronchoscopy be-cause of tracheal stenosis,strains were identified by amplifying the sequences of 16S rRNA ,femA and mecA with real-time quantitative polymerase chain reaction (PCR),homology analysis of strains were performed by Spa geno-typing.Results All 12 MRSA-infected patients were susceptible to multidrug-resistance bacterial infection,5 cases of MRSA infection occurred during this hospitalization.Detection of specimens from health care workers and envi-ronment were all negative;Spa gene of all 12 MRSA isolates was type t 030 ,which was the main epidemic strain in Asia;Spa gene of Staphylococcus aureus isolated from nurses’noses was type t1425 .Conclusion The assumption of MRSA spread among health care workers aren’t supported by the epidemiological investigation results,genotypes of 12 MRSA isolates are identical,but the result of gene typing can’t be as the evidence of homology of infection ;patients at high risk for MRSA infection should be screened as early as possible,early contact isolation should be performed,so as to prevent and control the occurrence of HAI.

OBJECTIVE:To study the rational use of antibacterials in inpatients.METHODS:A discussion was made on the use of antibacterials for 4 948 inpatients in 2004 and 5 476 inpatients in 2005 in our hospital,managed in accordance with the requirements for hospital management by level and the Guidelines for Clinical Use of Antibacterials.RESULTS & CONCL- USIONS:The inpatient use of antibacterials in our hospital has been made basically rational through implementation of systematic management,enactment of antibacterials management by level,monitoring on usage of antibacterials and enforcement of warning system for overusing.