Effects of 60Co-γ Ray Radicidation on Instant Tea

Effects of 60Co-γ ray radicidation on instant tea were studied through contaminant microbe assay,absorbed dose measurement and analysis of principal components of instant tea.The minimum effective dose of 4.0kGy and maximum tolerance dose of 8.0KGy were proposed.

Investigation on the binding of （-）-epigallocatechin-3-O-gallate to bovine serum albumin by molecular spectroscopy

The binding of （-）-epigallocatechin-3-O-gallate （EGCG） to bovine serum albumin （BSA） were investigated for the first time with spectral methods, including fluorescence and absorption spectrometry under simulative physiological conditions. A strong fluorescence quenching reaction of EGCG to BSA was observed. It was proved that the fluorescence quenching of BSA by addition of EGCG was a result of the formation of EGCG-BSA complex. The binding constant K and the number of binding sites n were determined at physiological conditions and three different temperatures with fluorescence quenching method. The binding distance R and transfer efficiency E between BSA and EGCG were also obtained according to Forster theory of non-radiation energy transfer. The effects of Al^3＋, Cu^2＋, Mg^2＋ and Fe^2＋ on the binding constant between EGCG and BSA were studied at 298 K. The effect of EGCG on the conformation of BSA was also analyzed by synchronous fluorescence spectroscopy. PACS. 21. 10. Dr; 32. 50. ＋d; 32. 30. Jc; 82.80. Dx

Biocidal Effect of Gamma Radiation on the Ecology of Filamentous Fungal Populations Associated with Stone Deterioration

This study focused on the identification of the filamentous fungi associated with soapstone samples exposed to outdoor conditions and the biocidal effect of gamma radiations on isolated fungal populations in Minas Gerais State in Brazil. Two soapstone blocks were placed outdoors under tropical environmental conditions for 12 months. A total of 9 filamentous fungal populations were identified on their surfaces, namely Acremomium （cf.） alternatum, Alternaria alternata, Aspergillusfumigatus, Calcarisporium （cf.） arbuscula, Cladosporium cladosporioides, Curvularia lunata, Epicoccum nigrum, Fusarium equiseti and Penicillium citrinum. The gamma radiation assay was then carried out as a test of biocidal action by exposing all fungal populations to the ionizing radiation. The results showed that only the C. cladosporioides species was resistant to this biocidal agent, since it was able to increase its population post exposure. Scanning electron microscopy images identified the microbial colonization on the soapstone blocks and the stone elementar composition was analyzed by energy dispersive X-ray spectrometry. After treatment, there was no structural and aesthetic alteration in the soapstone samples, and evidencing that gamma radiation can be used as a biocidal agent. However, the resistance of the black fungal population indicates caution in the choice of gamma irradiation as biocidal treatment.

ACL reconstruction with BPTB autograft and irradiated fresh frozen allograft

Objective： To analyze the clinical outcomes of arthroscopic anterior cruciate ligament （ACL） reconstruction with irradiated bone-patellar tendon-bone （BPTB） allograft compared with non-irradiated allograft and autograft. Methods： All BPTB allografts were obtained from a single tissue bank and the irradiated allografts were sterilized with 2.5 mrad of irradiation prior to distribution. A total of 68 patients undergoing arthroscopic ACL reconstruction were prospectively randomized consecutively into one of the two groups （autograft and irradiated allograft groups）. The same surgical technique was used in all operations done by the same senior surgeon. Before surgery and at the average of 31 months of follow-up （ranging from 24 to 47 months）, patients were evaluated by the same observer according to objective and subjective clinical evaluations. Results： Of these patients, 65 （autograft 33, irradiated allograft 32） were available for full evaluation. When the irradiated allografl group was compared to the autograft group at the 31 -month follow-up by the Lachman test, the anterior drawer test （ADT）, the pivot shift test, and KT-2000 arthrometer test, statistically significant differences were found. Most importantly, 87.8% of patients in the autograft group and just only 31.3% in the irradiated allograft group had a side-to-side difference of less than 3 mm according to KT-2000. The failure rate of the ACL reconstruction with irradiated allograft （34.4%） was higher than that with autograft （6.1%）. The anterior and rotational stabilities decreased significantly in the irradiated allograft group. According to the overall International Knee Documentation Committee （1KDC）, functional and subjective evaluations, and activity level testing, no statistically significant differences were found between the two groups. Besides, patients in the irradiated allograft group had a shorter operation time and a longer duration of postoperative fever. When the patients had a fever, the laboratory examinations of all patients were almost normal. Blood routine was normal, the values of erythrocyte sedimentation rate （ESR） were 5-16 mm/h and the contents of C reactive protein （CRP） were 3-10 mg/L. Conclusion： We conclude that the short term clinical outcomes of the ACL reconstruction with irradiated BPTB allograft were adversely affected. The less than satisfactory results led the senior authors to discontinue the use of irradiated BPTB allografl in ACL surgery and not to advocate using the gamma irradiation as a secondary sterilizing method.