Byeong-Keun Kim

Detection of γ-Irradiated Sesame Seeds before and after Roasting by Analyzing Photostimulated Luminescence, Thermoluminescence, and Electron Spin Resonance

Sesame seeds were irradiated using a (60)Co irradiator (0-4 kGy) and then roasted (220 degrees C for 10 min). To identify the irradiation treatment, physical detection methods like photostimulated luminescence (PSL), thermoluminescence (TL), and electron spin resonance (ESR) have been investigated before and after roasting. The photon counts of the irradiated samples (nonroasted and roasted) were higher than those of nonirradiated ones, making it possible to distinguish the two samples. The threshold values of nonroasted and roasted samples increased linearly with the irradiation dose, respectively. The TL for the nonirradiated nonroasted and roasted samples presented a lower peak at about 300 degrees C, but irradiated samples showed a higher peak at around 150 degrees C. The areas of TL glow curves were 15 times higher in nonroasted as compared with roasted samples. TL ratio [integrated area of TL 1 (the first glow)/TL 2 (the second glow)] obtained by the reirradiation step was 0 in nonirradiated samples and more than 0.15 in irradiated samples. The radiation-induced ESR signals originating from cellulose were determined in irradiated samples before and after roasting.

Study of photostimulated- and thermo-luminescence characteristics for detecting irradiated kiwifruit.

Photostimulated luminescence (PSL) and thermo-luminescence (TL) analyses were conducted to detect irradiated kiwifruits. Samples were irradiated with Co-60 gamma-rays at 0-2 kGy. The freeze-dried kiwifruit peel showed 309 photon counts (PCs) for nonirradiated samples that accounted for less than the lower threshold value (700 counts/60 s, negative) and above 9306 PCs for 1 and 2 kGy-irradiated samples, which was higher than the upper threshold value (5000 counts/60 s, positive). However, PSL signals of irradiated samples remarkably decreased after 6 weeks of storage. The TL measurement using minerals isolated from the whole kiwifruit surface revealed a glow curve (TL 1) with a low intensity at 200-300 degrees C in nonirradiated samples but with a higher intensity at around 180 degrees C in irradiated samples at 1 kGy or more. The TL ratios, integrated areas of TL 1/TL 2 that was measured after 1 kGy re-irradiation for the TL 1-tested minerals, were less than 0.1 in nonirradiated samples and higher than 0.1 in irradiated ones and could verify TL 1 results. The inorganic dust minerals used were mainly composed of feldspar and quartz.

Identification of red pepper powder irradiated with different types of radiation using luminescence methods: A comparative study

The purpose of this study was to verify the reliability of photostimulated luminescence (PSL) and thermoluminescence (TL) methods for identifying irradiated foods, described in the European standards EN 13751:2002 and EN 1788:2001, respectively, which were established solely through interlaboratory studies on gamma-irradiated food. Red pepper powder samples irradiated with electron-beams (e-beams), gamma rays and high-energy X-rays were used as model foods. Samples irradiated with each radiation type at ⩾4 kGy could be correctly identified by the PSL method, whereas samples irradiated at ⩾0.5 kGy with each radiation type could be correctly recognized by the TL method when e-beams, gamma rays, or high-energy X-rays were used as normalization sources. However, different TL intensities were observed for minerals separated from red pepper powder for different irradiation sources, which was confirmed using pure quartz and K-feldspar minerals. Further interlaboratory studies are required to verify this phenomenon.

Perianal Crohn's disease with a clenched fist-like appearance

Editor Crohn’s disease (CD) is a chronic granulomatous disease of the gastrointestinal tract, especially the terminal ileum, but it may also show extraintestinal involvement including the eyes, lips, oral cavity, anus, joints or skin. Among these areas, the skin is the most common site for perianal, perineal, or peristomal involvement. Perianal CD can be an extraintestinal manifestation of the socalled ‘metastatic disease’ or the direct extension of the intestinal CD. However, perianal CD can be presented various clinical features; a large mass lesion with a peculiar appearance, as in this case, is very rare. We, herein, describe a case of a perianal CD that was assumed to be the direct extension from the involved bowel by observing classic inflammatory lesions of CD on the perianal mucosal area and it characteristically had a clenched fist–like appearance. A 32-year-old Korean woman was referred to our department with a gradually enlarging mass on the perianal area for 6 years. Upon close observation, the mass lesion surrounded the anal orifice and it appeared like a ‘baby’s clenched fist’ (Fig. 1a). She complained of intermittent itching. Six years ago, she had received colonoscopy due to repetitive lower abdominal pain with severe diarrhea for several weeks. Colonoscopic finding had shown various inflammatory lesions and she had been diagnosed as intestinal CD (Fig. 1b). She had been taking medication intermittently. Except for elevated erythrocyte sedimentation rate level, other laboratory findings that included a complete blood cell count, liver and renal function tests, screening for syphilis and urinalysis revealed no abnormal findings. Histopathological findings of the lesion showed non-caseating granulomatous inflammation which was composed of lymphocytes, epitheloid cells and multinucleated giant cells in the dermis (Fig. 2). Condyloma accuminata, haemorrhoids, and cancer were excluded since there was no evidence of koilocytosis, dilated veins, or atypical cells. The human papillomavirus DNA typing of the specimen also showed negative results. The patient was finally diagnosed as having perianal CD through clinicohistopathological correlation, but she was not available for the further follow-up due to personal circumstances. The cutaneous manifestation of CD is important as it can be an early marker of disease and it can provide guidance to the proper diagnosis. In addition, perianal involvement occurs in about 30% of CD cases and it helps to distinguish CD from other inflammatory bowel diseases in which perianal involvement is very rare. In most cases, perianal CD is presented in the form of an abscess (23–62%), fissure (21–35%), fistula (6–34%), ulcer (1.9–5.1%), anal stricture, and skin tag. In addition to these types, other forms of perianal CD such as maceration, patch, plaque, and erosion have been reported. Regarding the current case, however, a large mass lesion with unique appearance was not found in literature. Considering Figure 1 (a) The mass appears as baby’s clenched fist (inset) that surrounded anal orifice. (b) Colonoscopic finding shows erythema, erosions, ulcers and pseudopolyps on the perianal mucosal area of distal rectum.

Applicability of thermoluminescence techniques to identify irradiated seafoods using different methods of mineral separation: An interlaboratory blind trial

Thermoluminescence (TL) technique for identifying γ-irradiated (0–10 kGy) anchovies (dried), kelp (dried), and mackerel (fresh) was validated in an interlaboratory blind trial. Different irradiation detection laboratories were involved by using 2 methods of mineral separation (density separation and acid hydrolysis) for the analysis. Key TL parameters, including the TL glow-curve shape, intensity, and the TL ratio (TL1/TL2) were used to characterize the irradiation status. All irradiated samples exhibited an intense TL peak at approximately 200°C, which was absent in non-irradiated samples. TL glow curve interpretations were also confirmed by determining the TL ratio. Different participating laboratories reported 89–100% correct results. Both methods of mineral separation were equally effective; however, some variation was observed in the results from different laboratories for irradiated mackerel, which might be due to a lack of isolated minerals, differences in personnel expertise, and different TL instruments.