D0 Values Research Articles

후춧가루의 위생화를 위한 감마선, 전자선 및 X-선 조사 효과 비교

This study evaluated the effects of a gamma ray (GR), electron beam (EB), and X-ray (XR) to improve the safety of black pepper powder. The black pepper powder was irradiated by GR, EB, and XR at 2, 4, 6, 8, and 10 kGy. The results of the total bacterial populations in the black pepper power sample showed a similar effect on microbial decontamination for radiation sources. Radiation sensitivity (D10 value) on the initial bacteria loads in the sample was 2.24 kGy in GR, 2.37 kGy in EB, and 2.75 kGy in XR. In addition, there were no differences among the radiation sources. The color values, such as L (lightness), a (redness), and b (yellowness), were not changed significantly. The sensory characteristics of GR, EB, and XR irradiated black pepper powder were decreased when the radiation dose increased, but there was no significant changes among the radiation sources. The results can be applied to investigate the effects of radiation sources on the microbiological and sensory characteristics of black pepper powder.

Effects of gamma irradiation on the physical and sensory quality and inactivation of Listeria monocytogenes in blue swimming crab meat (Portunas pelagicus)

Blue swimming crab lump (backfin) meat were exposed to 2, 4, and 6kGy doses of Co60 irradiation and evaluated for changes in physical, sensory properties, and Listeria monocytogenes inactivation. Irradiation up to 6kGy resulted in no textural changes (p>0.05) in maximum shear forces; however, these exposures resulted in sensory quality changes (p<0.05) as determined by a triangle overall difference test (n=50) at each irradiation level. Irradiation had no effect (p>0.05) on L⁎ color value. Irradiation at 4 and 6kGy resulted in listericidal reductions greater than 6.65 (Department of Medical Science, Ministry of Health, Thailand, [DMST] 1783) and 7.56 logs (DMST 4553). Irradiation doses of 1 and 2kGy resulted in a reduction of 2.10 and 5.35 logs respectively of L. monocytogenes DMST 1783 and 1.56 and 4.19 logs respectively of L. monocytogenes DMST 4553. The D10 values of L. monocytogenes DMST 1783 and 4553 were 0.35 and 0.45kGy. The study indicated that low-dose gamma irradiation would increase the safety of blue swimming crab meat without unacceptable changes in texture and L⁎ color value.

Analysis of the unstressed lattice spacing, d0, for the determination of the residual stress in a friction stir welded plate of an age-hardenable aluminum alloy – Use of equilibrium conditions and a genetic algorithm

Procedures based on equilibrium conditions (stress and bending moment) have been used to obtain an unstressed lattice spacing, d0, as a crucial requirement for calculating the residual stress (RS) profile across a joint conducted on a 10mm thick plate of age-hardenable AA2024 alloy by friction stir welding (FSW). Two procedures have been used that take advantage of neutron diffraction measurements. First, equilibrium conditions were imposed on sections parallel to the weld so that a constant d0 value corresponding to the base material region could be calculated analytically. Second, balance conditions were imposed on a section transverse to the weld. Then, using the data and a genetic algorithm, suitable d0 values for the different regions of the weld have been found. For several reasons, the comb method has proved to be inappropriate for RS determination in the case of age-hardenable alloys. However, the equilibrium conditions, together with the genetic algorithm, has been shown to be very suitable for determining RS profiles in FSW joints of these alloys, where inherent microstructural variations of d0 across the weld are expected.

Effects of electron-beam irradiation on blueberries inoculated with Escherichia coli and their nutritional quality and shelf life

Fresh blueberries have become a popular new functional food because of their remarkably high levels of antioxidant phytonutrients and health benefits. However, the potential prevalence of human pathogens on blueberries has become an increased concern because they are consumed fresh. Procedures effective in decontamination and extending shelf life without affecting fruit quality are needed. Electron-beam irradiation was applied to fresh blueberries at the doses ranging from 0.5 to 3.0kGy and its effectiveness for inactivating Escherichia coli (E. coli) K-12 and extending shelf life were investigated. The decimal reduction dose, D10 values, of E. coli in cultural medium and blueberries were 0.43±0.01kGy and 0.37±0.015kGy, respectively. Irradiation reduced bacteria inoculated on blueberries from 7.7×108CFU/g to 6CFU/g at 3.13kGy and decreased the decaying of blueberries stored at 4°C up to 72% and at room temperature up to 70% at this dose. No significant effect on the total monomeric anthocyanins, antioxidant activity, and l-ascorbic acid content of blueberries was observed from irradiation at doses ≤3kGy. However, significant decreases in the antioxidant activity and l-ascorbic acid content were found in both control and irradiated blueberries after storage at 4°C for 7 and 15 d. Information obtained in this study indicates that low dose electron-beam irradiation is effective in reducing E. coli and extending shelf life while maintaining the antioxidant properties of blueberries.

Radiosensitization of Aspergillus niger and Penicillium chrysogenum using basil essential oil and ionizing radiation for food decontamination

Stored products may be contaminated by pathogenic fungi such as Fusarium, Aspergillus and Penicillum. Fumigation with plant essential oil (EO) and irradiation treatment are options to control spoilage organisms. Basil essential oil and irradiation were tested alone and in combination for their antifungal effects in rice. Minimum Inhibitory Concentration (MIC) of basil EO was found to be 0.1% (v/v) against Aspergillus niger and Penicillium chrysogenum after 48 h. Radiosensitization of A. niger and P. chrysogenum in presence of 1% or 2% (v/v) basil EO was evaluated in vitro and in situ. At 1 and 2% of basil EO, the in vitro D10 value was 0.43 and 0.31 kGy respectively for A. niger and 0.44 and 0.34 kGy respectively for P. chrysogenum. In inoculated rice, D10 values for controls (sample without EO) were 0.67 and 0.63 kGy for A. niger and P. chrysogenum respectively, and the values were decreased at higher EO concentrations. For A. niger, a 2% (v/wt) basil EO alone caused a 0.42 to 1.18 log reduction on days 1 and 14 respectively, whereas treatment with 2 kGy radiation alone caused a 2.18 log reduction. The combined treatments resulted in a 4.6 log reduction of A. niger after 14 days of storage. For P. chrysogenum, 2% basil EO alone caused a 0.76 and a 1.12 log reduction on days 1 and 14 respectively, whereas a 2 kGy radiation dose caused a 2.41 log reduction. The combined treatments resulted in a 5.0 log reduction of P. chrysogenum after 14 days of storage. The findings demonstrated the potential of basil EO as antifungal agent and its efficacy to increase the radiosensitivity of A. niger and P. chrysogenum during irradiation treatment.

Autofluidization of pyroclastic flows propagating on rough substrates as shown by laboratory experiments

AbstractThis study investigates the influence of the substrate surface roughness on the emplacement mechanisms of pyroclastic flows. We carried out laboratory experiments on gravitational flows generated from the release of initially fluidized or nonfluidized columns of fine particles (diameter d = 0.08 mm) in a horizontal channel. The roughness of the channel base was uniform in each experiment, created by gluing particles of diameter d0 = 0.08 to 6 mm to the base. Other things being equal, the flow runout distance increased with the channel base roughness (d0) to a maximum of about twice that of flows on a smooth substrate when d0 = 1.5–3 mm, before decreasing moderately at higher roughness values of d0 = 6 mm. Long runout originated mainly during the late stages of emplacement as flow deceleration was strongly reduced at high substrate roughness. This was caused by (partial) autofluidization due to an upward air flux escaping from the substrate interstices in which flow particles settled. Autofluidization was evidenced by high pore fluid pressure measurements at the base of initially nonfluidized flows and also by reduced flow runout when the interstices were initially partially filled so that less air was available. Furthermore, the runout distance of flows of large particles (d = 0.35 mm), which could not be fluidized by the ascending air flux, was independent of the substrate roughness. This study suggests that autofluidization caused by air escape from the interstices of a rough substrate is one important mechanism to explain the common long runout distance of pyroclastic flows even on subhorizontal topographies.

Genotoxicity of charged particles of importance in space flight using murine kidney epithelial cells

Ionizing radiation presents significant challenges for human space flight including an increased cancer risk. High-energy heavy ions in the galactic cosmic radiation can produce qualitative and quantitative differences in biological effects when compared with sparsely ionizing radiations. Mutations are induced by charged particle exposure and are integral to the formation and/or progression of human cancers. Most cancer-associated mutations occur on autosomal chromosomes, and most solid cancers occur in epithelial tissues. Here, a combined in vitro/in vivo approach was used to evaluate cell killing and the induction of mutations at a model autosomal locus, Aprt, in mouse kidney epithelium. For in vitro exposures, Aprt heterozygous kidney cells (clones 1a, 4a or 6a) were used from C57BL/6×DBA/2 mice. Additional experiments were performed using whole body irradiation of mice with the same genotype. Both males and females were irradiated in approximately equal numbers. Irradiations were performed at the NASA Space Radiation Laboratories at Brookhaven National Laboratory. For in vitro studies, cells from primary kidney clones were irradiated and seeded at limiting dilution immediately post-irradiation to determine the toxicity of the treatment. The irradiated kidney cells were also seeded in mutation assays within 1 week post-irradiation to determine the Aprt mutant fraction at the earliest time post-exposure. This work was complemented by studies wherein mice were exposed to the same ions with kidneys harvested several months post-irradiation to determine the residual toxicity and the Aprt mutant fraction. Our previous studies focused on sparsely ionizing 1 GeV protons (LET = 0.24 keV/µm) and densely ionizing 1 GeV/amu Fe ions (LET = 151 keV/µm). Our most recent studies have included work with Si ions (240 MeV/amu for in vitro studies, LET = 78 keV/µm; 263 MeV/amu initial energy for in vivo studies to achieve 78 keV/µm near the midline of the animal) and O ions (250 MeV/amu in vitro studies only, LET = 25 keV/µm). Toxicity for the cultured kidney cells in vitro follows this pattern: Fe > Si > O > protons when the results are expressed per unit dose. D0 values were 92 cGy for Fe ions, 103 cGy for Si ions, 192 cGy for O ions and 340 cGy for protons. With regard to the induction of Aprt mutations, Fe ions were more mutagenic than protons. Si ions were also quite mutagenic with evidence for a linear dose–response for Aprt mutations in kidney cells exposed in vitro or in kidneys harvested from mice irradiated several months earlier. These results are consistent with the linear dose–response data obtained previously for Aprt mutation induction following Fe ion exposure in vitro or in vivo, but the results for Si ions differ from the curvilinear dose–response data we recently published following similar exposures to energetic protons [ 1, 2]. Our most recent studies examined the molecular characteristics of Si ion-induced Aprt mutants following in vitro exposure. A dose of 160 cGy was used to collect 58 Aprt kidney cell mutants. Mutational events were classified as follows based on PCR-based analyses of polymorphic markers along mouse chromosome 8: intragenic events, apparent mitotic recombination, interstitial deletions of Aprt only, multilocus deletions, discontinuous loss of heterozygosity or whole chromosome loss. The results for this group of mutants will be compared against our previous studies on Aprt mutants arising after exposure to sparsely ionizing 1 GeV protons or densely ionizing 1 GeV/amu Fe ions. Additional studies are ongoing to define mutational spectra following Si ion exposure to kidney epithelium in vivo.Clinical Trial Registration number: not applicable.

Accurate determination of the binding energy of the formic acid dimer: The importance of geometry relaxation

The formic acid dimer in its C2h-symmetrical cyclic form is stabilized by two equivalent H-bonds. The currently accepted interaction energy is 18.75 kcal/mol whereas the experimental binding energy D0 value is only 14.22 ±0.12 kcal/mol [F. Kollipost, R. W. Larsen, A. V. Domanskaya, M. Nörenberg, and M. A. Suhm, J. Chem. Phys. 136, 151101 (2012)]. Calculation of the binding energies De and D0 at the CCSD(T) (Coupled Cluster with Single and Double excitations and perturbative Triple excitations)/CBS (Complete Basis Set) level of theory, utilizing CCSD(T)/CBS geometries and the frequencies of the dimer and monomer, reveals that there is a 3.2 kcal/mol difference between interaction energy and binding energy De, which results from (i) not relaxing the geometry of the monomers upon dissociation of the dimer and (ii) approximating CCSD(T) correlation effects with MP2. The most accurate CCSD(T)/CBS values obtained in this work are De = 15.55 and D0 = 14.32 kcal/mol where the latter binding energy differs from the experimental value by 0.1 kcal/mol. The necessity of employing augmented VQZ and VPZ calculations and relaxing monomer geometries of H-bonded complexes upon dissociation to obtain reliable binding energies is emphasized.

Deinococcus soli sp. nov., a Gamma-Radiation-Resistant Bacterium Isolated from Rice Field Soil

A Gram-negative, non-motile, short rod-shaped bacterial strain, designated N5(T), was isolated from a rice field soil in South Korea. Phylogenetic analysis based on the 16S rRNA gene sequence of the new isolate showed that strain N5(T) belongs to the genus Deinococcus, family Deinococcaceae, showing the highest sequence similarity to Deinococcus grandis KACC 11979(T) (98.4 %) and Deinococcus daejeonensis KCTC 13751(T) (97.5 %). Strain N5(T) exhibits resistance to gamma-radiation similar to that of other members of the genus Deinococcus, with a D10 value in excess of 4 kGy. Chemotaxonomic data showed that the most abundant fatty acids are C16:1ω7c (25.25 %), C15:1ω6c (19.77 %), C17:1ω6c (11.87 %), and C17:0 (9.41 %), and the major polar lipid is an unknown phosphoglycolipid. The predominant respiratory quinone is menaquinone MK-8. The DNA G+C content is 71.4 mol%. Phenotypic, phylogenetic, and chemotaxonomic data support designation of strain N5(T) as a novel species of the genus Deinococcus, for which the name Deinococcus soli sp. nov. is proposed. The type strain is N5(T) (=KCTC 33153(T) = JCM 19176(T)).

Synergistic effect of the combined treatment with gamma irradiation and sodium dichloroisocyanurate to control gray mold (Botrytis cinerea) on paprika

Gray mold (Botrytis cinerea) is one of the most major fungal pathogens in paprika. Generally, gamma irradiation over 1kGy is effective for the control of fungal pathogens; however, a significant change in fruit quality (physical properties) on paprika was shown from gamma irradiation at over 0.6kGy (p<0.05). Therefore, in this study, the synergistic disinfection effect of the combined treatment with gamma irradiation and sodium dichloroisocyanurate (NaDCC) was investigated to reduce the gamma irradiation dose. In an artificial inoculation experiment of B. cinerea isolated from naturally-infected postharvest paprika, fungal symptoms were observed in the stem and exocarp of paprika after conidial inoculation. From the sensitivity of gamma irradiation and NaDCC, B. cinerea conidia were fully inactivated by 4kGy of gamma irradiation (D10 value 0.99kGy), and were fully inactivated by 50ppm NaDCC treatment. The fungal symptoms were not detected by the dose-dependent gamma irradiation (>4kGy) and NaDCC (>50ppm). As a result of the combined treatment of gamma irradiation and NaDCC, the D10 value was significantly reduced by 1.06, 0.88, 0.77, and 0.58kGy (p<0.05). Moreover, fungal symptoms were more significantly reduced in combined treatment groups (gamma irradiation and NaDCC) than single treatment groups (gamma irradiation or NaDCC). These results suggest that combined treatment with irradiation and NaDCC treatment can be applied to preserve quality of postharvest paprika or other fruits.

Improvement of microbiological safety and sensorial quality of pork jerky by electron beam irradiation and by addition of onion peel extract and barbecue flavor

The combined effects of electron-beam (EB) irradiation and addition of onion peel (OP) extract and barbecue flavor (BF) on inactivation of foodborne pathogens and the quality of pork jerky was investigated. Prepared pork jerky samples were irradiated (0, 1, 2, and 4kGy) and stored for 2 month at 25°C. The D10 values of Listeria monocytogenes, Escherichia coli, and Salmonella typhimurium observed in the OP treated samples were 0.19, 0.18, and 0.19kGy, whereas those in control were 0.25, 0.23, and 0.20kGy, respectively. Irradiated samples with OP extract and BF had substantially lower total aerobic bacterial counts than the control had. Samples with added OP extract and BF had lower peroxide values than the control had. Sensory evaluation indicated that overall acceptability of treated samples was not changed up to 2kGy. Therefore, EB irradiation, combined with OP extract and BF, has improved the microbiological safety with no negative effects on the quality of pork jerky.

Biological Effectiveness of Carbon-Ion Radiation on Various Human Breast Cancer Cell Lines

Introduction: Carbon-ion radiotherapy (C-ion RT) is known as a highly effective local treatment and its relative biological effectiveness (RBE) has been evaluated for various types of malignant tumors. There are only a few studies on C-ion radio sensitivity in breast cancer, and there has been no evaluation by subtypes. To estimate the impact of C-ion RT for breast cancer, RBE of C-ion beams of various types of human breast cancer cell lines was evaluated by comparison with X-rays. Methods: Six human breast cancer cell lines with different subtypes, Luminal-human epidermal growth factor receptor 2 (HER2)-negative (MCF-7), Luminal-HER2-positive (BT-474), Her2-enriched (SK-BR-3), Basal-like (MDAMB- 468, HCC1937) and ductal carcinoma in situ (MCF10DCIS.com) were used. Radio sensitivities were assessed with survival curves created from colony-forming assay (CFA) and high-density surviving assay (HDS). An X-ray generator was used with 200 kV, 20 mA. The Heavy Ion Medical Accelerator in Chiba (HIMAC) was used for C-ion irradiation, with 290 MeV/u, mono-peak, linear energy transfer (LET) of 80 KeV/μm. Results: CFA was not suitable for BT474, SK-BR-3, MDA-MB-468, and HCC1937 because of their low plating efficiency. The differences between the D10 values on HDS were large with X-ray, and the survival curve shoulders for MCF7, MDA-MB-468, and MCF10DCIS.com were wide. On the other hand, the differences between the D10 values were small with C-ion beams, and the survival curves were linear without shoulders for all cell lines except a small shoulder with MCF10DCIS.com. The RBE value of C-ion beams was 2.3 to 3.6, median 2.9 in all cell lines by CFA and HDS. Conclusion: RBE around 3 by C-ion beams was seen in many types of ductal cancer. The small survival curve shoulder on MCF10DCIS.com suggested that non invasive ductal carcinoma is relatively more resistant than invasive cancer.

RelB-siRNA enhanced the radiosensitivity of murine prostate cancer cell line RM-1

To explore the transfecting effects of RelB small interfering RNA (RelB-siRNA) on murine prostate cancer cell line RM-1 sensitivity of radiotherapy. The RM-1 cells were divided into RelB-siRNA vector, empty vector, non-transfection and normal groups. After transfection, the first three groups were irradiated by X ray. Clone formation array method was used to measure the surviving fraction and the relevant parameter values after 0, 2, 4, 6, 8 Gy irradiation. Apoptotic rate was measured via Annexin V/PI flow cytometry after 6 Gy irradiation. The level of RelBmRNA was estimated by real-time polymerase chain reaction (PCR) after 6 Gy irradiation. And the RelB protein of cytoplasm and nucleus was detected by Western blot after 6 Gy irradiation. Clone formation array showed that RelB group at each dose point corresponding to the survival fraction were lower that the empty vector nd non-transfection groups. The D0, Dq and SF2 values of RelB group were 1.68, 0.60, 0.43, lower than those of empty vector group 1.92, 3.08, 0.89 and non-transfection group 1.93, 2.76, 0.84. Annexin V/PI flow cytometry demonstrated that the apoptotic rate of RelB group was 15.27% ± 1.62% and it was significantly higher than the non-transfection group 7.90% ± 1.50% and the empty vector group 8.40% ± 0.69% respectively (P < 0.01) .Real-time PCR indicated that RelB-mRNA amplification of RelB group was 1.18 ± 0.03 and it was significantly lower than the non-transfection group 2.10 ± 0.61 and the empty vector group 1.97 ± 0.66 respectively (P < 0.01) .Western blot suggested that cytoplasmic gray-scale ratio of RelB group was 0.50 ± 0.08 and it was significantly lower than the non-transfection 1.77 ± 0.19 and the empty group 1.52 ± 0.12 respectively (P < 0.01) . And the nuclear gray-scale radio of the RelB group was 0.18 ± 0.03 and it was significantly lower than the non-transfection group 0.61 ± 0.12 and the empty group 0.54 ± 0.13 respectively (P < 0.01) . The RelB protein inhibition rates of cytoplasmic and nuclear RelB-siRNA were 71.8% and 70.4% respectively. RelB-siRNA can effectively inhibit the RelB expression of murine prostate cancer cell line RM-1 and significantly increase its sensitivity to radiotherapy.

Deinococcus radiotolerans sp. nov., a gamma-radiation-resistant bacterium isolated from gamma ray-irradiated soil

Two gamma-radiation-resistant bacterial strains, designated C1(T) and C2, were isolated from a soil sample collected at Jeongeup-Si, South Korea. These strains were observed to be Gram-negative, non-motile, rod-shaped, and to form pink colonies. Phylogenetic analysis based on 16S rRNA gene sequences revealed that these strains belong to the genus Deinococcus in the family Deinococcaceae. Strains C1(T) and C2 have the highest sequence similarities with Deinococcus daejeonensis MJ27(T) (97.56%) and Deinococcus grandis DSM 39663(T) (97.50%). Like other members of the genus Deinococcus, the novel isolates showed resistance to gamma-radiation with a D10 value in excess of 8kGy. The isolates were found to have menaquinone MK-8 as the predominant respiratory quinone and an unidentified phosphoglycolipid as major polar lipid. In addition, the most abundant fatty acids of strain C1(T) were identified as C15:1 ω6c (25.5%), C16:1 ω7c (18.7%) and C15:0 (9.7%). Genomic analysis results showed that the DNA G+C contents of strain C1(T) and C2 are 68.59 and 68.57%, respectively. Taken together, the polyphasic taxonomic data support the proposal that the isolates C1(T) and C2 represent a novel species of the genus Deinococcus, for which the name Deinococcus radiotolerans sp. nov. is proposed. The type strain is a strain C1(T) (=KCTC 33150(T)=JCM 19173(T)).

Removal of toxic Co-EDTA complex by a halophilic solar-salt-pan isolate Pseudomonas aeruginosa SPB-1

In this study, a promising bioremediation approach was developed to remove [Co(III)-EDTA]− complex that is generated during the waste management process. Though several studies have been reported on bioremediation of cobalt, the removal of [Co(III)-EDTA]− complex has not been tested. A [Co(III)-EDTA]− resistant bacterium, Pseudomonas aeruginosa SPB-1 was isolated from the solar-salt-pan and physical parameters were optimized for its growth. The various studies showed that the removal of [Co(III)-EDTA]− from the bulk liquid was due to the adsorption of the complex by the biomass. Using absorption/desorption isotherm over a range of pH (1–8), the maximum adsorption of [Co(III)-EDTA]− was found to be at pH 7.0 and maximum desorption from the biomass occurred at pH 1.0, thus rendering an ion exchange property to P. aeruginosa SPB-1 biomass. P. aeruginosa SPB-1 biomass could be used as bio-resin that showed 80.4±3.27% adsorption capacity up to fourth cycle and the biomass was viable till the ninth cycle with 10.5±7.3% adsorption. Radiation tolerance potential i.e. D10 value for the strain was found to be ∼300Gy, which suggests the potential use of the bacterium in bioremediation of moderately active nuclear waste.

Hymenobacter swuensis sp. nov., a Gamma-Radiation-Resistant Bacteria Isolated from Mountain Soil

Gram stain-negative and non-motile bacteria, designated as DY53(T) and DY43, were isolated from mountain soil in South Korea prior exposure with 5 kGy gamma radiation. Phylogenetic analysis based on 16S rRNA gene sequence revealed that the strains belonged to the family Cytophagaceae in the class Cytophagia. 16S rRNA gene sequence similarity of strains DY53(T) and DY43 was 100 %. The highest degrees of sequence similarities of strains DY53(T) and DY43 were found with Hymenobacter perfusus A1-12(T) (98.8 %), Hymenobacter rigui WPCB131(T) (98.5 %), H. yonginensis HMD1010(T) (97.9 %), H. xinjiangensis X2-1g(T) (96.6 %), and H. gelipurpurascens Txg1(T) (96.5 %). The DNA G+C content of the novel strains DY53(T) and DY43 were 59.5 mol%. Chemotaxonomic data revealed that strains possessed major fatty acids such as C₁₅:₀ iso, C₁₅:₀ anteiso, C₁₆:₁ ω5c, summed feature 3 (16:1 ω7c/ω6c), summed feature 4 (17:1 anteiso B/iso I) and C₁₇:₀ iso, and major polar lipid was phosphatidylethanolamine. The novel strains showed resistance to gamma radiation, with a D10 value (i.e., the dose required to reduce the bacterial population by tenfold) in excess of 5 kGy. Based on these data, strains DY53(T) and DY43 should be classified as representing a novel species, for which the name Hymenobacter swuensis sp. nov. is proposed, with the type strain DY53(T) (=KCTC 32018(T) = JCM 18582(T)) and DY43 (=KCTC 32010).

Normal Tissue Tolerance of Microplanar Beam X-ray: A Long-term Observation

and 6 Gy. Twenty-four hours after irradiation, cells were re-plated and surviving fractions measured by clonogenic assay. Results: Polyamide treatment alone did not decrease surviving fraction in the absence of irradiation. The radiosensitization by polyamide treatment increased with radiation dose. Surviving fractions at 2 Gy were 0.660.07 and 0.550.05 (SER 1.2); at 4 Gy were 0.410.02 and 0.220.02 (SER 1.9); at 6 Gy were 0.220.07 and 0.110.01 (SER 2.0) for vehicle and polyamidetreated cells, respectively. Calculated D0 values were 4.16 Gy (vehicle) and 2.79 Gy (polyamide). SER: sensitization enhancement ratio. Errors are standard deviations (n Z 3). Conclusions: The polyamide demonstrated radiosensitization of UM-SCC12 cells in vitro. These results justify continued investigations into the therapeutic combination of irradiation and minor groove binding polyamides. Author Disclosure: N. Nickols: None. F. Yang: None. J.A. Ratikan: None. B.C. Li: None. W.H. McBride: None. P.B. Dervan: None.

Dating Middle Pleistocene loess from Stari Slankamen (Vojvodina, Serbia) — Limitations imposed by the saturation behaviour of an elevated temperature IRSL signal

Recent advances in post-IR IRSL dating have led to breakthroughs in dating upper Middle Pleistocene loess sequences. Here, an elevated temperature post-IR IR protocol using a second IR stimulation temperature of 290°C is applied to eleven polymineral fine-grain (4–11μm) samples from the lower part of the Middle–Lower Pleistocene Stari Slankamen loess–palaeosol sequence with the aim of refining the site's age model and investigating the behaviour of both the IR50 and the pIRIR290 signals in material close to or in luminescence signal saturation. Both signals from the 8 samples below the prominent erosion surface represented by a gravel layer at ~13m were found to be in field saturation (i.e. no systematic increase in burial dose with depth). The average ratio of the sensitivity-corrected natural signal to the laboratory saturation level for the pIRIR290 is 1.00±0.03 (n=8) indicating that field saturation is equal to laboratory saturation for this signal. Minimum equivalent dose estimates were calculated from 2*D0 values, giving minimum age estimates of ~230–390ka; this result suggests an upper limit for dating these loess deposits of ~300ka. The age estimate of the younger sample SSK2 is in good agreement with the quartz OSL age, showing that the pIRIR290 signal is bleachable in nature and can be used to date material as young as ~20ka. Our data suggest that the loess unit V-L2 accumulated during Marine Isotope Stage (MIS) 6 and that the erosional event marked by an unconformity and gravel layer between loess units V-L2 and V-L3 has a minimum age of ~170ka. Pedocomplex V-S1 can be correlated with the complete MIS 5 period. Furthermore we suggest a minimum age of ~250ka for the loess unit V-L3 and palaeosols V-S3, V-S4 and V-S5; considerably older than proposed by many previous studies.

Distortion and residual stress measurements of induction hardened AISI 4340 discs

10 Induction hardened discs with two initial hardness levels were used for exploring the influences of the variation of initial hardness as well as induction hardening (IH) recipes on the heat treatment distortions and hardening depth. The results show that for the same initial hardness, the larger the energy input, the higher the distortion size as well as the hardening depth. For a given induction hardening recipe, the increase in initial hardness leads to a deeper hardening depth but a smaller distortion. One disc was selected for the residual stress investigation in three orthogonal directions by neutron diffraction (ND). The corresponding stress-free lattice spacing d0 was measured from the same material using both ND and X-ray diffraction (XRD) methods. The ND results show that the variation of d0 in the hardened layer is significant and should be taken into account for stress calculation. However, regarding the core region, the d0 value measured by XRD is more reliable. Accordingly, a combination of the ND-measured d0 profiles in the hardened layer and the XRD-measured d0 value in the core was adopted for the determination of residual stress distributions.

Evaluation of potential ionizing irradiation protectors and mitigators using clonogenic survival of human umbilical cord blood hematopoietic progenitor cells

We evaluated the use of colony formation (colony-forming unit-granulocyte macrophage [CFU-GM], burst-forming unit erythroid [BFU-E], and colony-forming unit-granulocyte-erythroid-megakaryocyte-monocytes [CFU-GEMM]) by human umbilical cord blood (CB) hematopoietic progenitor cells for testing novel small molecule ionizing irradiation protectors and mitigators. The following compounds were added before (protection) or after (mitigation) ionizing irradiation: GS-nitroxides (JP4-039 and XJB-5-131), the bifunctional sulfoxide MMS-350, the phosphoinositol-3-kinase inhibitor LY29400, triphenylphosphonium-imidazole fatty acid, the nitric oxide synthase inhibitor (MCF-201-89), the p53/mdm2/mdm4 inhibitor (BEB55), methoxamine, isoproterenol, propranolol, and the adenosine triphosphate-sensitive potassium channel blocker (glyburide). The drugs XJB-5-131, JP4-039, and MMS-350 were radiation protectors for CFU-GM. JP4-039 was also a radiation protector for CFU-GEMM. The drugs XJB-5-131, JP4-039, and MMS-350 were radiation mitigators for BFU-E, MMS-350 and JP4-039 were mitigators for CFU-GM, and MMS350 was a mitigator for CFU-GEMM. In contrast, other drugs were effective in murine assays; TTP-IOA, LY294002, MCF201-89, BEB55, propranolol, isoproterenol, methoxamine, and glyburide but showed no significant protection or mitigation in human CB assays. These data support the testing of new candidate clinical radiation protectors and mitigators using human CB clonogenic assays early in the drug discovery process, thus reducing the need for animal experiments.