Radionuclides content in grape molasses soil samples from Central Black Sea region of Turkey

The activity concentrations of radionuclides in grape molasses soil samples collected from Zile (Tokat) plain in the Central Black Sea region of Turkey were measured by using gamma spectrometer with a NaI(Tl) detector. Also, the concentrations of ²²²Rn in soil samples and air were estimated essentially taking the activity concentrations of ²²⁶Ra measured in soil samples. Grape molasses soil samples with calcium carbonate content are used for sedimentation for making molasses in this region. The average activity concentrations of ²³²Th, ²²⁶Ra, ⁴⁰K, and ¹³⁷Cs were found as 62 ± 2, 68 ± 3, 479 ± 35, and 8.0 ± 0.3 Bq kg^?1, respectively. The average concentrations of ²²²Rn in soil samples and air were estimated to be 50 kBq m^?3 and 144 Bq m^?3. From the activity concentrations, absorbed gamma dose rate in outdoor air (D), annual effective dose from external exposure (E_E), annual effective dose from inhalation of radon (E_I), and excess lifetime cancer risk (ELCR) were estimated in order to assess radiological risks. The average values of D, E_E, E_I, and ELCR were found to be 90 nGy h^?1, 110 μSv y^?1, 1360 μSv y^?1, and 4 × 10^?4, respectively.     

NUNDO: a numerical model of a human torso phantom and its application to effective dose equivalent calculations for astronauts at the ISS

The health effects of cosmic radiation on astronauts need to be precisely quantified and controlled. This task is important not only in perspective of the increasing human presence at the International Space Station (ISS), but also for the preparation of safe human missions beyond low earth orbit. From a radiation protection point of view, the baseline quantity for radiation risk assessment in space is the effective dose equivalent. The present work reports the first successful attempt of the experimental determination of the effective dose equivalent in space, both for extra-vehicular activity (EVA) and intra-vehicular activity (IVA). This was achieved using the anthropomorphic torso phantom RANDO^® equipped with more than 6,000 passive thermoluminescent detectors and plastic nuclear track detectors, which have been exposed to cosmic radiation inside the European Space Agency MATROSHKA facility both outside and inside the ISS. In order to calculate the effective dose equivalent, a numerical model of the RANDO^® phantom, based on computer tomography scans of the actual phantom, was developed. It was found that the effective dose equivalent rate during an EVA approaches 700 μSv/d, while during an IVA about 20 % lower values were observed. It is shown that the individual dose based on a personal dosimeter reading for an astronaut during IVA results in an overestimate of the effective dose equivalent of about 15 %, whereas under an EVA conditions the overestimate is more than 200 %. A personal dosemeter can therefore deliver quite good exposure records during IVA, but may overestimate the effective dose equivalent received during an EVA considerably.     

<Superscript>131</Superscript>I age-dependent inhalation dose in Southern Poland from Fukushima accident

A general method for calculating doses absorbed from isotopes released in nuclear accidents is presented. As an example, this method was used to calculate doses for inhabitants of Southern Poland due to inhalation of ¹³¹I released due to the Fukushima nuclear plant accident. ¹³¹I activity measurements in the air of that region provided the basis for the study. The proposed model is based on a complex biokinetic model for iodine merging the Leggett model developed in 2010 with the human respiratory tract and gastrointestinal tract models recommended by the International Commission on Radiological Protection (ICRP). This model is described here, and it is demonstrated that resulting dose estimates are consistent with those obtained using the ICRP methodology. Using the developed model, total doses were calculated for six age groups of both genders, for gaseous and aerosol fractions alike. The committed effective dose, H ₅₀, for an adult man reached 16 nSv, which is lower than 0.001% of the background dose. The dose for the thyroid of an adult reached 0.33 μSv, which corresponds to circa 0.0007% of the dose to the population of Southern Poland after the Chernobyl nuclear plant accident.     

Evaluation of Outdoor Gamma Dose Rate and Cancer Risk in Artvin Province,Turkey

In this study, we measured environmental outdoor gamma dose rates (terrestrial and cosmic) in 204 stations across the province of Artvin. The average outdoor gamma dose rate for the province of Artvin was found to be 174.81 nGy/h. The radiological map of Artvin was drawn with the help of measured outdoor gamma dose rates. Annual effective dose equivalent and lifetime cancer risk values were figured up for the adults in Artvin province by using measured outdoor gamma dose rates. The average annual dose equivalent and excess lifetime cancer risk were 214.5 μSv/y and 7.5 × 10^?4, respectively. The values acquired were compared with the similar studies done around the world. The average annual effective dose equivalent and excess lifetime cancer risk were found to be approximately three times higher than the world average.     

Blood clearance and occupational exposure for <Superscript>177</Superscript>Lu-DOTATATE compared to <Superscript>177</Superscript>Lu-PSMA radionuclide therapy

The main target of this work is to examine blood clearance and external exposure for ¹⁷⁷Lu-DOTATATE compared with new emerging ¹⁷⁷Lu-PSMA therapy. Blood clearance and radiation exposure of 31 patients treated with 5.5?±?1.1 GBq ¹⁷⁷Lu-DOTATATE were compared to those of 23 patients treated with 7.4 GBq ¹⁷⁷Lu-PSMA. Dose rates were measured at several distances and time points up to 120 h after treatment. Blood samples were collected conjunctively after infusion. Caregiver’s cumulative dose was measured by means of an OSL (optically stimulated luminescence) dosimeter for 4–5 days and medical staff’s dose was also estimated using electronic personal dosimeters. Finger dose was determined via ring TLD (Thermoluminescence Dosimeter) for radiopharmacists and nurses. Dose rates due to ¹⁷⁷Lu-DOTATATE at a distance of 1 m, 4 h and 6 h after infusion, were 3.0?±?2.8 and 2?±?1.9 µSv/(h GBq), respectively, while those due to ¹⁷⁷Lu-PSMA were 3.1?±?0.8 and 2.2?±?0.9 µSv/(h GBq). Total effective dose of 17 caregivers was 100–200 µSv for ¹⁷⁷Lu-DOTATATE therapy. Mean effective doses to nurses and radiopharmacists were 5 and 4 µSv per patient, respectively, while those for physicists and physicians were 2 µSv per patient. For ¹⁷⁷Lu-DOTATATE, effective half-life in blood and early elimination phase were 0.31?±?0.13 and 4.5?±?1 h, while they were found as 0.4?±?0.1 and 5?±?1 h, respectively, for ¹⁷⁷Lu-PSMA. The first micturition time following ¹⁷⁷Lu-DOTATATE infusion was noted after 36?±?14 min, while the second and third voiding times were after 74?±?9 and 128?±?41 min, respectively. It is concluded that blood clearance and radiation exposure for ¹⁷⁷Lu-DOTATATE are very similar to those for ¹⁷⁷Lu-PSMA, and both treatment modalities are reasonably reliable for outpatient treatment, since the mean dose rate [2.1 µSv/(h GBq)] decreased below the dose rate that allows release of the patient from the hospital (20 µSv/h) after 6 h at 1 m distance.     

Occupational cosmic radiation exposure in Portuguese airline pilots: study of a possible correlation with oxidative biological markers

Several studies have sought to understand the health effects of occupational exposure to cosmic radiation. However, only few biologic markers or associations with disease outcomes have so far been identified. In the present study, 22 long- and 26 medium-haul male Portuguese airline pilots and 36 factory workers who did not fly regularly were investigated. The two groups were comparable in age and diet, were non-smokers, never treated with ionizing radiation and other factors. Cosmic radiation exposure in pilots was quantified based on direct monitoring of 51 flights within Europe, and from Europe to North and South America, and to Africa. Indirect dose estimates in pilots were performed based on the SIEVERT (Système informatisé d’évaluation par vol de l’exposition au rayonnement cosmique dans les transports aériens) software for 6,039 medium- and 1,366 long-haul flights. Medium-haul pilots had a higher cosmic radiation dose rate than long-haul pilots, that is, 3.3 ± 0.2 μSv/h and 2.7 ± 0.3 μSv/h, respectively. Biological tests for oxidative stress on blood and urine, as appropriate, at two time periods separated by 1 year, included measurements of antioxidant capacity, total protein, ferritin, hemoglobin, creatinine and 8-hydroxy-2-deoxyguanosine (8OHdG). Principal components analysis was used to discriminate between the exposed and unexposed groups based on all the biological tests. According to this analysis, creatinine and 8OHdG levels were different for the pilots and the unexposed group, but no distinctions could be made among the medium- and the long-haul pilots. While hemoglobin levels seem to be comparable between the studied groups, they were directly correlated with ferritin values, which were lower for the airline pilots.     

Improving acclimatization through the photoautotrophic culture of coconut (Cocos nucifera) seedlings: an in vitro system for the efficient exchange of germplasm

An in vitro photoautotrophic step based on the supply of CO₂-enriched air (1,600 μmol mol^?1) during the light phase and ambient air (350 μmol mol^?1 CO₂) during the dark phase has been used to promote the ex vitro establishment of coconut (Cocos nucifera L.) seedlings. The introduction of this step into a previously developed in vitro protocol was found to improve the quality of the seedlings (as assessed by fresh weight increase, physical stature, leaf area and thickness, stomatal density, and chlorophyll a content, and primary and secondary root production), the proportion of seedlings successfully transferred to soil (improvement from 40% to 100%) and achieved in a shorter time (reduction from 10 to 6 mo). Best results using this photoautotrophic growth step were obtained when a low medium concentration of sucrose (43.8 mM or lower) was used, when it was applied to seedlings that had already reached 4 or 5 mo of age in the in vitro culture step, and when seedlings were cultured in the photoautotrophic system for 2 mo or more before transfer to soil. Our improved protocol is more efficient and it reduces the cost per plant for the international exchange of coconut germplasm.     

An estimation of Canadian population exposure to cosmic rays

The worldwide average exposure to cosmic rays contributes to about 16% of the annual effective dose from natural radiation sources. At ground level, doses from cosmic ray exposure depend strongly on altitude, and weakly on geographical location and solar activity. With the analytical model PARMA developed by the Japan Atomic Energy Agency, annual effective doses due to cosmic ray exposure at ground level were calculated for more than 1,500 communities across Canada which cover more than 85% of the Canadian population. The annual effective doses from cosmic ray exposure in the year 2000 during solar maximum ranged from 0.27 to 0.72 mSv with the population-weighted national average of 0.30 mSv. For the year 2006 during solar minimum, the doses varied between 0.30 and 0.84 mSv, and the population-weighted national average was 0.33 mSv. Averaged over solar activity, the Canadian population-weighted average annual effective dose due to cosmic ray exposure at ground level is estimated to be 0.31 mSv.     

Contamination with ergot bodies (<Emphasis Type="Italic">Claviceps purpurea sensu</Emphasis><Emphasis Type="Italic">lato</Emphasis>) of two horse pastures in Northern Germany

Because the occurrence of Claviceps in European pastures may have been overlooked to cause serious health problem for grazing animals, we documented the degree of Claviceps contamination in two horse pastures and estimated whether the horses could have ingested a critical quantity of alkaloids. We counted the Claviceps sclerotia and determined alkaloid levels using high performance liquid chromatography with fluorescence detection. Depending on the location, the number of sclerotia varied from 0.09 to 0.19 per square meter (central area) and from 0.23 to 55.8 per square meter (border strips). Alkaloid levels in individual sclerotia also varied in different genera of grasses, ranging from 0.98 ± 0.17 μg/kg in Agrostis sp. to 25.82 ± 9.73 μg/kg in Dactylis sp., equivalent to 0.98 μg/kg and 7.26 mg/kg. Sclerotia from Dactylis contained high levels of ergosine (0.209 % ± 0.100 %) and ergocristine (0.374 % ± 0.070 %). Depending on the localization in pastures, alkaloid levels in forage (dry matter, DM) ranged from 16.1 to 45.4 μg/kg in central areas and from 23.9 to 722 μg/kg in border strips. The amount of alkaloids that a horse could have ingested depended on its daily DM uptake, which was higher in the central areas (5.85 kg/day) than in the border strips (2.73 or 0.78 kg/day). In the central areas, this amount of alkaloids ranged from 94.2 to 265.9 μg/day; and in the border strips, from 65.3 (in 2.73 kg DM/day) to as much as 563.8 μg/day (in 0.78 kg DM/day). All these amounts are higher than the European averages for alkaloids ingested by horses via feedstuffs.     

Acaricidal activities of bicyclic monoterpene ketones from Artemisia iwayomogi against Dermatophagoides spp.

The acaricidal properties of 1,7,7-trimethylbicyclo[2.2.1]heptan-2-one isolated from Artemisia iwayomogi and its structural analogues were evaluated against Dermatophagoides farinae and D. pteronyssinus, and their effects were compared with that of the commercial acaricide benzyl benzoate. Based on the 50 % lethal dose (LD₅₀) values against D. farinae, 1,7,7-trimethylbicyclo[2.2.1]heptan-2-one (0.82 μg/cm²) was 9.71 times more effective than benzyl benzoate (7.96 μg/cm²), followed by (1R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one (1.03 μg/cm²), (1S)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one (1.58 μg/cm²), and (1R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one oxime (3.05 μg/cm²) in a filter paper bioassay. The acaricidal activities of 1,7,7-trimethylbicyclo[2.2.1]heptan-2-one and its structural analogues against D. pteronyssinus were similar to those against D. farinae. These results demonstrate that naturally occurring A. iwayomogi-isolated 1,7,7-trimethylbicyclo[2.2.1]heptan-2-one and its structural analogues are suitable for the production of natural acaricides against house dust mites.     

A natural plant growth promoter,calliterpenone, enhances growth and biomass,carbohydrate, and lipid production in cyanobacterium Synechocystis PCC 6803

Cyanobacteria have evolved photosynthetic mechanisms in which solar energy is used to fix CO₂ into carbohydrates. The lipids from cyanobacteria can be converted to biodiesel by extraction–transesterification methods. The present study demonstrates the usefulness of the natural plant and microbial growth promoter calliterpenone from the plant Callicarpa macrophylla supplemented at three different doses (15, 25, 50 μL of a 0.01 mM solution) per 100 mL BG11⁺ medium for enhancing total biomass, carbohydrate, and lipid yields and reducing the surface-to-volume ratios of cells of Synechocystis PCC 6803. The enhanced total dried biomass, carbohydrate, and lipid production was 316.1, 140.34, and 130.76 %, respectively, higher than the control, and were obtained after 15 days of cultivation at the dose of 15 μL (0.01 mM) of calliterpenone per 100 mL BG11⁺ medium. A decrease in surface-to-volume ratio of cells from 1.19 to 0.84 compared to the control was also observed. Response surface methodology was used to optimize the doses of calliterpenone at different pH of growth media. An increase of 346.95, 187.2, and 134.46 % in biomass, carbohydrate, and lipid yields, respectively, was achieved after 10 days of cultivation in optimized BG11⁺ media at pH 7.5 and with 20 μL (0.01 mM) calliterpenone per 100 mL. Thus, this biomolecule can be exploited for higher yields of Synechocystis PCC 6803 in a relatively shorter culture time making this an attractive strategy for fuel production using this cyanobacterium.     

High-Frequency Regeneration by Abscisic Acid (ABA) from Petiole Callus of Jatropha curcas

Jatropha curcas L. is attaining worldwide interest as an important biofuel crop. Experiments were conducted to improve the prevailing micropropagation technique as well as to develop a new ex vitro rooting method for J. curcas plant regeneration. Regeneration and ex vitro rooting efficiency was enhanced by augmenting the culture medium with abscisic acid (ABA). Different concentrations of 6-benzylaminopurine (BAP) and indole-3-butyric acid (IBA) were tested for callus generation from both in vitro and in vivo explants (leaf and petiole) on Murashige and Skoog (MS) medium. The best regenerative callus was achieved on MS medium supplemented with BAP (4.44 μM) and IBA (2.45 μM) from in vitro-cultured petioles. Highest regeneration (91%) was achieved by culturing petiole callus on MS medium supplemented with BAP (8.88 μM), IBA (0.49 μM), and ABA (1.9 μM), whereas 61% regeneration was obtained from in vitro leaf callus. Shoot proliferation and elongation was achieved on BAP (2.22 μM) and IAA (8.56 μM) with 10–13 shoots per explants. Highest rooting (65%) was achieved from M1 shoots (BAP, IAA, and ABA) on MS medium supplemented with IBA (2.45 μM), naphthaleneacetic acid NAA (0.54 μM), and 0.02% activated charcoal. Ex vitro rooting of 1-mo-old M1 shoots obtained from the charcoal-containing medium resulted optimum rooting (>72%) when transferred to polybags containing sterile sand. The plantlets were successfully acclimatized in soil with more than 98% survival rate in the greenhouse.     

Occupational exposure to low doses of ionizing radiation and cataract development: a systematic literature review and perspectives on future studies

Ionizing radiation is a well-known but little understood risk factor for lens opacities. Until recently, cataract development was considered to be a deterministic effect occurring at lens doses exceeding a threshold of 5–8 Gy. Substantial uncertainty about the level and the existence of a threshold subsists. The International Commission on Radiation Protection recently revised it to 0.5 Gy. Based on a systematic literature review of epidemiological studies on exposure to low levels of ionizing radiation and the occurrence of lens opacities, a list of criteria for new epidemiological studies was compiled, and a list of potential study populations was reviewed. Among 24 publications finally identified, six report analyses of acute exposures in atomic bomb survivors and Chernobyl liquidators, and the others report analyses of protracted exposures in occupationally, medically or accidentally exposed populations. Three studies investigated a dose threshold: in atomic bomb survivors, the best estimates were 1 Sv (95 % CI <0–0.8 Sv) regarding lensectomies; in survivors exposed as children, 0.6 Sv (90 % CI <0.0–1.2 Sv) for cortical cataract prevalence and 0.7 Sv (90 % CI 0.0–2.8 Sv) for posterior subcapsular cataract; and in Chernobyl liquidators, 0.34 Sv (95 % CI 0.19–0.68 Sv) for stage 1 cataract. Current studies are heterogeneous and inconclusive regarding the dose–response relationship. Protracted exposures and high lens doses occur in several occupational groups, for instance, in physicians performing fluoroscopy-guided interventional procedures, and in accidentally exposed populations. New studies with a good retrospective exposure assessment are feasible and should be initiated.     

Urinary zearalenone measured with ELISA as a biomarker of zearalenone exposure in pigs

The suitability to assess zearalenone (ZEA) exposure in pigs of a commercial ELISA kit for ZEA analysis in urine was tested. A daily dose of 0, 5, 10, 20 and 40 μg synthetic ZEA per kilogram BW was administered via the feed to four gilts per dose group, and after 3 and after 7 days of ZEA intake, urine samples were assayed with the ELISA which has a relative cross-reactivity of 42 % with α-zearalenol. The concentration of urinary ZEA equivalents (ZEA plus 42 % of α-zearalenol present) did not differ between day 4 and day 8 (P?=?0.50) within each dose group. The urinary ZEA equivalent/creatinine ratio was tightly correlated with ZEA intake (r?=?0.95). The urinary ZEA equivalent/creatinine values at 0 and 40 μg/kg BW were distinctly different from those of the intermediate dose levels, whereas there was some overlapping of the individual values at the dose levels 5, 10 and 20 μg/kg BW. The urinary ZEA equivalent/creatinine ratio can be used as a biomarker for ZEA exposure in pigs provided that urine samples of several animals receiving the same diet are assayed, either separately or after pooling.     

Laboratory Study Comparing Pharmacopeial Testing of Nebulizers with Evaluation Based on Nephele Mixing Inlet Methodology

Determination of fine droplet dose with preparations for nebulization, currently deemed to be the metric most indicative of lung deposition and thus in vivo responses, involves combining two procedures following practice as described in the United States Pharmacopeia and the European Pharmacopeia. Delivered dose (DD) is established by simulating tidal breathing at the nebulizer, collecting the medication on a filter downstream of the nebulizer mouthpiece/facemask. Fine droplet fraction (FDF_<x μm) is determined separately using a cooled cascade impactor operated at 15 L/min. FDD_<x μm is subsequently calculated as the product of DD and FDF_<x μm. Development of the Nephele mixing inlet has allowed cascade impactor-based assessments to be made at a constant flow rate while simultaneously subjecting the nebulizer to the continuously varying flow profile associated with breath simulation. The study purpose was to investigate the feasibility of this approach, termed mixing inlet lung simulation (MILS), for direct determination of FDD_<x μm. An optimal upper size limit for FDF is not given for nebulizers, but 5 μm was chosen since this limit is the European norm when testing other inhalation products. Vibrating membrane nebulizers (eFlow® Rapid) were used to deliver aqueous salbutamol sulfate, simulating an adult tidal-breathing pattern (inspiratory to expiratory ratio = 1:1, tidal volume = 500 mL, 15 breaths per minute, peak inspiratory flow rate = 24 L/min). The two procedures were inequivalent, as FDD_<5 μm by the MILS approach was 72% of that obtained using the compendial “combination” method. Since the MILS methodology more closely mimics clinical use, we infer that the compendial approach likely overestimates the dose reaching the human lung.     

Plant regeneration of non-toxic Jatropha curcas—impacts of plant growth regulators, source and type of explants

Jatropha curcas is an oil bearing species with multiple uses and considerable economic potential as a biofuel plant, however, oil and deoiled cake are toxic. A non-toxic variety of J. curcas is reported from Mexico. The present investigation explores the effects of different plant growth regulators (PGRs) viz. 6-benzyl aminopurine (BAP) or thidiazuron (TDZ) individually and in combination with indole-3-butyric acid (IBA), on regeneration from in vitro and field-grown mature leaf explants, in vitro and glasshouse-grown seedlings cotyledonary leaf explants of non-toxic J. curcas. In all the tested parameters maximum regeneration efficiency (81.07%) and the number of shoot buds per explants (20.17) was observed on 9.08 μM TDZ containing Murashige and Skoog’s (MS) medium from in vitro cotyledonary leaf explants. The regenerated shoot buds were transferred to MS medium containing 10 μM kinetin (Kn), 4.5 μM BAP and 5.5 μM α-naphthaleneacetic acid (NAA) for shoot proliferation. The proliferated shoots could be elongated on MS medium supplemented with 2.25 μM BAP and 8.5 μM IAA. Rooting was achieved when the basal cut end of elongated shoots were dipped in half strength MS liquid medium containing different concentrations and combinations of IBA, IAA and NAA for four days followed by transfer to growth regulators free half strength MS medium supplemented 0.25 mg/l activated charcoal. The rooted plants could be established in soil with more than 90% survival rate.     

Method of testing insecticide susceptibility of Stenotus rubrovittatus (Hemiptera: Miridae) by topical application

Appropriate droplet size and the preferred sex and age of insects for insecticides used in topical application were investigated to standardize the method of testing the susceptibility of Stenotus rubrovittatus (Matsumura). The overflow of acetone droplets applied on the notum of the thorax of S. rubrovittatus adults occurred when the droplet size exceeded 0.20 μl per insect, and the overflow occurred more frequently in males than in females. No effect of acetone solution on mortality was observed at less than 0.20 μl droplet size per insect within 72 h after treatment. The LD₅₀ values and relative potencies of fenitrothion 24 and 48 h after treatment were almost the same in each sex. The fenitrothion susceptibility of males was twice higher than that of females. The fenitrothion susceptibility increased with age after emergence. However, there were small differences in LD₅₀ values and relative potencies between 4–7 and 8–11 days after emergence because the females 4–11 days after emergence had a small difference in body weight. These results led us to conclude that the recommended size of acetone droplets per insect is less than 0.20 μl and that it is suitable to use S. rubrovittatus females 4–11 days after emergence for topical application.     

Dose and dose rate extrapolation factors for malignant and non-malignant health endpoints after exposure to gamma and neutron radiation

Murine experiments were conducted at the JANUS reactor in Argonne National Laboratory from 1970 to 1992 to study the effect of acute and protracted radiation dose from gamma rays and fission neutron whole body exposure. The present study reports the reanalysis of the JANUS data on 36,718 mice, of which 16,973 mice were irradiated with neutrons, 13,638 were irradiated with gamma rays, and 6107 were controls. Mice were mostly Mus musculus, but one experiment used Peromyscus leucopus. For both types of radiation exposure, a Cox proportional hazards model was used, using age as timescale, and stratifying on sex and experiment. The optimal model was one with linear and quadratic terms in cumulative lagged dose, with adjustments to both linear and quadratic dose terms for low-dose rate irradiation (<5 mGy/h) and with adjustments to the dose for age at exposure and sex. After gamma ray exposure there is significant non-linearity (generally with upward curvature) for all tumours, lymphoreticular, respiratory, connective tissue and gastrointestinal tumours, also for all non-tumour, other non-tumour, non-malignant pulmonary and non-malignant renal diseases (p < 0.001). Associated with this the low-dose extrapolation factor, measuring the overestimation in low-dose risk resulting from linear extrapolation is significantly elevated for lymphoreticular tumours 1.16 (95% CI 1.06, 1.31), elevated also for a number of non-malignant endpoints, specifically all non-tumour diseases, 1.63 (95% CI 1.43, 2.00), non-malignant pulmonary disease, 1.70 (95% CI 1.17, 2.76) and other non-tumour diseases, 1.47 (95% CI 1.29, 1.82). However, for a rather larger group of malignant endpoints the low-dose extrapolation factor is significantly less than 1 (implying downward curvature), with central estimates generally ranging from 0.2 to 0.8, in particular for tumours of the respiratory system, vasculature, ovary, kidney/urinary bladder and testis. For neutron exposure most endpoints, malignant and non-malignant, show downward curvature in the dose response, and for most endpoints this is statistically significant (p < 0.05). Associated with this, the low-dose extrapolation factor associated with neutron exposure is generally statistically significantly less than 1 for most malignant and non-malignant endpoints, with central estimates mostly in the range 0.1–0.9. In contrast to the situation at higher dose rates, there are statistically non-significant decreases of risk per unit dose at gamma dose rates of less than or equal to 5 mGy/h for most malignant endpoints, and generally non-significant increases in risk per unit dose at gamma dose rates ≤5 mGy/h for most non-malignant endpoints. Associated with this, the dose-rate extrapolation factor, the ratio of high dose-rate to low dose-rate (≤5 mGy/h) gamma dose response slopes, for many tumour sites is in the range 1.2–2.3, albeit not statistically significantly elevated from 1, while for most non-malignant endpoints the gamma dose-rate extrapolation factor is less than 1, with most estimates in the range 0.2–0.8. After neutron exposure there are non-significant indications of lower risk per unit dose at dose rates ≤5 mGy/h compared to higher dose rates for most malignant endpoints, and for all tumours (p = 0.001), and respiratory tumours (p = 0.007) this reduction is conventionally statistically significant; for most non-malignant outcomes risks per unit dose non-significantly increase at lower dose rates. Associated with this, the neutron dose-rate extrapolation factor is less than 1 for most malignant and non-malignant endpoints, in many cases statistically significantly so, with central estimates mostly in the range 0.0–0.2.     

Atmospheric methane removal by methane-oxidizing bacteria immobilized on porous building materials

Biological treatment using methane-oxidizing bacteria (MOB) immobilized on six porous carrier materials have been used to mitigate methane emission. Experiments were performed with different MOB inoculated in building materials at high (~20 % (v/v)) and low (~100 ppmv) methane mixing ratios. Methylocystis parvus in autoclaved aerated concrete (AAC) exhibited the highest methane removal rate at high (28.5?±?3.8 μg CH₄ g^?1 building material h^?1) and low (1.7?±?0.4 μg CH₄ g^?1 building material h^?1) methane mixing ratio. Due to the higher volume of pores with diameter >5 μm compared to other materials tested, AAC was able to adsorb more bacteria which might explain for the higher methane removal observed. The total methane and carbon dioxide-carbon in the headspace was decreased for 65.2?±?10.9 % when M. parvus in Ytong was incubated for 100 h. This study showed that immobilized MOB on building materials could be used to remove methane from the air and also act as carbon sink.     

Plant regeneration from cell suspension-derived protoplasts of Populus × beijingensis

A protocol for plant regeneration from cell suspension-derived protoplasts of Populus × beijingensis is described. Protoplasts were isolated from cell suspension cultures 6 d after subculture and further cultured in liquid NH₄NO₃-free Murashige and Skoog (MS) medium supplemented with 0.6 M glucose, 9.05 μM 2,4-dichlorophenoxyacetic acid, and 0.89 μM 6-benzyladenine at a density of 2?×?10⁵ protoplasts per milliliter. The initial plating efficiency and final plating efficiency recorded after 10 and 30 d reached 33.7 and 1.07%, respectively. The proliferated calli transferred to regeneration medium supplemented with 2.22 μM 6-benzyladenine and 0.54 μM α-naphthaleneacetic acid gave the highest rate of shoot formation (44.4%). All protoplast-derived shoots were able to form roots on half-strength MS medium supplemented with 2.46 μM indole-3-butyric acid.