Litter decomposes slowly on shaded steep slope and sunny gentle slope in a typical steppe ecoregion

Plant litter decomposition is mainly affected by litter properties and environmental factors, but the influence of terrain on litter decomposition is not well understood. We studied the effects of terrain on litter decomposition over a period of 12 months at six locations in a typical steppe ecoregion and measured the concomitant release of carbon (C), nitrogen (N), and phosphorus (P). The study site has two aspects, shaded and sunny, each aspect having three slopes: 15°, 30°, and 45°. The same mixed litter was used at each location to exclude the influence of litter quality variation. Results showed that soil temperature and moisture, solar radiation, and plant species diversity varied by terrain, which in turn, affected the k‐value (standardized total effects, 0.78, 0.12, 0.92, 0.23, respectively) and the release of C (0.72, –0.25, 0.83, 0.24, respectively), N (0.89, –0.45, 0.76, 0.40, respectively) and P (0.88, 0.77, 0.58, 0.57, respectively). K‐value and C release decreased with increasing slope on shaded aspect, while increased with increasing slope on sunny aspect. The release of N and P decreased with increasing slope on the shaded aspect. K‐value and C, N, and P release were significantly higher on shaded than that on sunny aspect at 15° and 30°, while at 45°, it was higher on sunny than on shaded aspect. The litter mass loss was slower on shaded 45° and sunny 15°. So moderate grazing or mowing could be used to reduce litter accumulation and accelerate litter decomposition on these terrains. Structural equation modeling indicated that soil temperature and solar radiation had the greatest influence on k‐value and C, N, and P release, and these two factors were directly related to soil moisture and plant species diversity. Overall, our results emphasize the need to consider terrain for litter decomposition in typical steppe ecoregions.     

Irradiation Sensitivity of Planktonic and Biofilm-Associated Escherichia coli O157:H7 Isolates Is Influenced by Culture Conditions

Ionizing radiation effectively inactivates Escherichia coli O157:H7, but the efficacy of the process against biofilm cells versus that against free-living planktonic cells is not well documented. The radiation sensitivity of planktonic or biofilm cells was determined for three isolates of E. coli O157:H7 (C9490, ATCC 35150, and ATCC 43894). Biofilms were formed on sterile glass slides incubated at 37°C for either 24 h, 48 h, or 72 h. The biofilm and planktonic cultures were gamma irradiated at doses ranging from 0.0 (control) to 1.5 kGy. The dose of radiation value required to reduce the population by 90% (D₁₀) was calculated for each isolate, culture, and maturity based on viable populations at each radiation dose. For each of the times sampled, the D₁₀ values of isolate 43894 planktonic cells (0.454 to 0.479 kGy) were significantly (P < 0.05) higher than those observed for biofilm cells (0.381 to 0.385 kGy), indicating a significantly increased sensitivity to irradiation for cells in the biofilm habitat. At the 24-h sampling time, isolate C9490 showed a similar pattern, in which the D₁₀ values of planktonic cells (0.653 kGy) were significantly higher than those for biofilm cells (0.479 kGy), while isolate 35150 showed the reverse, with D₁₀ values of planktonic cells (0.396 kGy) significantly lower than those for biofilm cells (0.526 kGy). At the 48-h and 72-h sampling times, there were no differences in radiation sensitivities based on biofilm habitat for C9490 or 35150. Biofilm-associated cells, therefore, show a response to irradiation which can differ from that of planktonic counterparts, depending on the isolate and the culture maturity. Culture maturity had a more significant influence on the irradiation efficacy of planktonic cells but not on biofilm-associated cells of E. coli O157:H7.     

Inactivation of Escherichia coli O157:H7 in Apple Juice by Irradiation

Three strains (932, Ent-C9490, and SEA13B88) of Escherichia coli O157:H7 were used to determine the effectiveness of low-dose gamma irradiation for eliminating E. coli O157:H7 from apple juice or cider and to characterize the effect of inducing pH-dependent, stationary-phase acid resistance on radiation resistance. The strains were grown in tryptic soy broth with or without 1% dextrose for 18 h to produce cells that were or were not induced to pH-dependent stationary-phase acid resistance. The bacteria were then transferred to clarified apple juice and irradiated at 2°C with a cesium-137 irradiator. Non-acid-adapted cells had radiation D values (radiation doses needed to decrease a microbial population by 90%) ranging from 0.12 to 0.21 kGy. D values increased to 0.22 to 0.31 kGy for acid-adapted cells. When acid-adapted SEA13B88 cells were tested in five apple juice brands having different levels of suspended solids (absorbances ranging from 0.04 to 2.01 at 550 nm), radiation resistance increased with increasing levels of suspended solids, with D values ranging from 0.26 to 0.35 kGy. Based on these results, a dose of 1.8 kGy should be sufficient to achieve the 5D inactivation of E. coli recommended by the National Advisory Committee for Microbiological Criteria for Foods.     

Sensitivity of Planktonic and Biofilm-Associated Salmonella spp. to Ionizing Radiation

Salmonella enterica forms biofilms that are relatively resistant to chemical sanitizing treatments. Ionizing radiation has been used to inactivate Salmonella on a variety of foods and contact surfaces, but the relative efficacy of the process against biofilm-associated cells versus free-living planktonic cells is not well documented. The radiation sensitivity of planktonic or biofilm-associated cells was determined for three food-borne-illness-associated isolates of Salmonella. Biofilms were formed on sterile glass slides in a coincubation apparatus, using inoculated tryptic soy broth, incubated at 37°C for 48 h. Resulting biofilms were 18 to 24 μm in height as determined by confocal scanning laser microscopy. The planktonic and biofilm cultures were gamma irradiated to doses of 0.0 (control), 0.5, 1.0, 1.5, 2.0 and 2.5 kGy. The D₁₀ value (the dose of radiation required to reduce a population by 1 log₁₀, or 90%) was calculated for each isolate-culture based on surviving populations at each radiation dose. The D₁₀ values of S. enterica serovar Anatum were not significantly (P < 0.05) different for biofilm-associated (0.645 kGy) and planktonic (0.677 kGy) cells. In contrast, the biofilm-associated cells of S. enterica serovar Stanley were significantly more sensitive to ionizing radiation than the respective planktonic cells, with D₁₀ values of 0.531 and 0.591 kGy, respectively. D₁₀ values of S. enterica serovar Enteritidis were similarly reduced for biofilm-associated (0.436 kGy) versus planktonic (0.535 kGy) cells. The antimicrobial efficacy of ionizing radiation is therefore preserved or enhanced in treatment of biofilm-associated bacteria.     

Sensorineural Hearing Loss after Combined Intensity Modulated Radiation Therapy and Cisplatin-Based Chemotherapy for Nasopharyngeal Carcinoma

PURPOSE: The incidence of sensorineural hearing loss (SNHL) after treatment with combination of intensity-modulated radiation therapy (IMRT) and cisplatin-based chemotherapy in nasopharyngeal carcinoma (NPC) patients was evaluated, and relationships of SNHL with host factors, treatment-related factors, and radiation dosimetric parameters were investigated. METHODS: Fifty-one NPC patients treated with IMRT from 2004 to 2009 were analyzed. All patients received neoadjuvant, concurrent, or adjuvant use of cisplatin. Pure tone audiometry was performed during the follow-up period with a median time of 60 months, ranging from 28 to 84 months. Correlation of SNHL at low frequencies (pure tone average, 0.5-2 kHz) with a series of factors was analyzed. RESULTS: Among 102 ears, 12.7% had low-frequency SNHL and 42.2% had high-frequency (4 kHz) SNHL. The incidence of low-frequency SNHL was greater in patients with age > 40, with T-stage 4, or who received cumulative cisplatin dose (CCD) > 200 mg/m² (P = .034, .011, and .003, respectively) and in ears with secretory otitis media (SOM) (P = .002). Several dosimetric parameters were found to be correlated with SNHL. Univariate analysis showed that the minimum radiation dose to 0.1 ml highest dose volume (D0.1 ml) of the cochlea was the best radiation-related predictive parameter. Multivariate analysis indicated that CCD, SOM, and D0.1 ml of cochlea (P = .035, .012, and .022, respectively) were the factors associated with SNHL. CONCLUSION: For NPC patients treated with IMRT and chemotherapy, the incidence of treatment-related SNHL was associated with CCD, D0.1 ml of cochlea, and SOM.     

Experimental and computational study of the radiation-induced decomposition of formaldehyde. Implications to cometary nuclei

The radiation-induced decomposition of aqueous solutions of formaldehyde was studied at 298 and 77 K in order to obtain an insight into the possible role of ionizing radiation on cometary chemistry. Aqueous solutions of 1.0 mol dm^–3 formaldehyde were exposed to -radiation in the dose range from 0.01 kGy to 1.2 MGy. The radiation chemical yield of decomposition of formaldehyde was determined to be: G(–CH₂(OH)₂)=26.3±1.2 at 298 K and G0.48 at 77 K.Based on previous estimates of the total dose of ionizing radiation that comets have accumulated over 4.6 billion years, we predict a radiation-induced depletion of formaldehyde as a function of depth in comet nuclei: 100% destruction in the outer layers (0–20 m) and 10% destruction in the interior layers.A Portion of this work was presented at the XXVIII COSPAR Plenary Meeting (MF. 7) held at the Hague, The Netherlands on June 25–26, 1990.     

Effect of ultraviolet radiation on chlorophyll,carotenoid, protein and proline contents of some annual desert plants

Investigation was carried out to find whether enhanced ultraviolet radiation influences the Malva parviflora L., Plantago major L., Rumex vesicarius L. and Sismbrium erysimoids Desf. of some annual desert plants. The seeds were grown in plastic pots equally filled with a pre-sieved normal sandy soil for 1 month. The planted pots from each species were randomly divided into equal groups (three groups). Plants of the first group exposed to white-light tubes (400–700 nm) 60 w and UV (365 nm) 8 w tubes. The second group was exposed to white-light tubes (400–700 nm) 60 w and UV (302 nm) 8 w tubes. The third group was exposed to white-light tubes (400–700 nm) 60 w and UV (254 nm) 8 w tubes, respectively, for six days. The results indicated that the chlorophyll contents were affected by enhanced UV radiation. The chlorophyll a, b, and total contents were decreased compared with the control values and reduced with the enhanced UV radiation, but the carotenoid was increased compared with the control and also reduced with the enhanced UV radiation. So, the contents of chlorophylls varied considerably. M. parviflora showed the highest constitutive levels of accumulated chlorophyll a, b, and total chlorophyll (0.463, 0.307 and 0.774 mg g⁻¹ f w) among the investigated plant species. P. major showed the lowest constitutive levels of the chloroplast pigments, 0.0036, 0.0038 and 0.0075 mg g⁻¹ f w for chlorophyll a, b, and total chlorophyll at UV-365 nm, respectively. The protein content was decreased significantly in both root and shoot systems compared with the control values but, it was increased with increasing wave lengths of UV-radiation of all tested plants. R. vesicarius showed the highest protein contents among the investigated plants; its content was 3.8 mg g⁻¹ f w at UV-365 nm in shoot system. On the other hand, decreasing ultraviolet wave length induced a highly significant increase in the level of proline in both root and shoot of all tested plants. From the results obtained, it is suggested that proline can protect cells against damage induced by ultraviolet radiation. Statistically, the variations of the studied metabolic activities were significant due to UV radiation treatment in shoot and root system of all investigated plant species.     

A novel danshensu derivative ameliorates experimental colitis by modulating NADPH oxidase 4‐dependent NLRP3 inflammasome activation

We have previously reported a novel compound [4‐(2‐acetoxy‐3‐((R)‐3‐(benzylthio)‐1‐methoxy‐1‐oxopropan‐2‐ylamino)‐3‐oxopropyl)‐1,2‐phenylene diacetate (DSC)], derived from danshensu, exhibits cytoprotective activities in vitro. Here, we investigated the effects and underlying mechanisms of DSC on dextran sodium sulphate (DSS)‐induced experimental colitis. We found that DSC treatment afforded significant protection against the development of colitis, evidencing by suppressed inflammatory responses and enhanced barrier integrity. Intriguingly, DSC specifically down‐regulated DSS‐induced colonic NADPH oxidase 4 (Nox4) expression, accompanied by a balanced redox status, suppressed nuclear factor‐κB (NF‐κB) and NLRP3 inflammasome activation and up‐regulated nuclear factor (erythroid‐derived 2)‐like 2 and haeme oxygenase‐1 expression. In vitro study also demonstrated DSC also markedly decreased Nox4 expression and activity associated with inhibiting reactive oxygen species generation, NF‐κB activation and NLRP3 inflammasome activation in bone marrow‐derived macrophages. Either lentiviral Nox4 shRNA‐mediated Nox4 knockdown or Nox4‐specific small‐interfering RNA mimicked effects of DSC by suppressing NLPR3 inflammasome activation to alleviate experimental colitis or inflammatory macrophage response. Collectively, our results provide the first evidence that DSC ameliorates experimental colitis partly through modulating Nox4‐mediated NLRP3 inflammasome activation.     

Improvement of oral availability of ginseng fruit saponins by a proliposome delivery system containing sodium deoxycholate

Ginseng fruit saponins (GFS) extracted from the ginseng fruit are the bioactive triterpenoid saponin components. The aim of the present study was to develop a drug delivery system called proliposome using sodium deoxycholate (NaDC) as a bile salt to improve the oral bioavailability of GFS in rats. The liposomes of GFS were prepared by a conventional ethanol injection and formed the solid proliposomes (P-GFS) using spray drying method on mannitol carriers. The formulation of P-GFS was optimized using the response surface methodology. The physicochemical properties of liposome suspensions including encapsulation efficiency, in vitro drug release studies, particle size of the reconstituted liposome were tested. The solid state characterization studies using the method of Field emission-scanning electron microscope (FE-SEM), Fourier transform infrared (FT-IR) and Differential scanning colorimetric (DSC) were tested to study the molecular state of P-GFS and to indicate the interactions among the formulation ingredients. In vitro studies showed a delayed release of ginsenoside Re (GRe). In vivo studies were carried out in rats. The concentrations of GRe in plasma of rats and its pharmacokinetic behaviors after oral administration of GFS, Zhenyuan tablets (commercial dosage form of GFS) and P-GFS were studied using ultra performance liquid chromatography tandem mass spectrometry. It was founded that the GRe concentration time curves of GFS, Zhenyuan tablets and P-GFS were much more different in rats. Pharmacokinetic behaviors of P-GFS showed a second absorption peak on the concentration time curve. The pharmacokinetic parameters of GFS, Zhenyuan tablets, P-GFS in rats were separately listed as follows: T max 0.25 h, C max 474.96 ± 66.06 ng/ml and AUC_0−∞ 733.32 ± 113.82 ng/ml h for GFS; T max 0.31 ± 0.043 h, C max 533.94 ± 106.54 ng/ml and AUC_0−∞ 1151.38 ± 198.29 ng/ml h for Zhenyuan tablets; T max 0.5 h, C max 680.62 ± 138.051 ng/ml and AUC_0−∞ 2082.49 ± 408.33 ng/ml h for the P-GFS. The bioavailability of P-GFS was nearly 284% and 181% of the GFS and Zhengyuan tablets respectively. In conclusion, the proliposomes significantly enhanced the drug bioavailability, absorption in the gastrointestinal tract and decreased its elimination time of GRe in rats and could be selectively applied for oral delivery of GFS.     

Catalytic decomposition of cellulose under biological conditions

1. The catalytic decomposition of undegraded cellulose in the form of cotton fibres is described with hydrogen peroxide at 0·4–0·04% (w/v) concentration in the presence of ferrous salts at pH3–5. 2. Complete solubilization of 5mg. of cotton fibres occurred in about 7 days in the presence of 0·4% hydrogen peroxide and 0·2mm-ferrous sulphate at the optimum pH4·2–4·3. 3. With 0·4% hydrogen peroxide the most rapid decomposition of cellulose was confined to ferrous sulphate concentrations of approx. 2–0·02mm. If the concentrations of the reagents were decreased in proportion extensive breakdown occurred but much more slowly. 4. In the primary stages of breakdown cotton fibres were disintegrated to very short fibres. These were subsequently solubilized, but there was little accumulation of soluble material. Organic matter was lost from solution as the reaction progressed. 5. Other naturally occurring cellulose-containing materials, such as grass, straw, hay and sawdust, were also disintegrated and solubilized by hydrogen peroxide and ferrous sulphate.     

Structural and Biochemical Studies of a Moderately Thermophilic Exonuclease I from Methylocaldum szegediense

A novel exonuclease, designated as MszExo I, was cloned from Methylocaldum szegediense, a moderately thermophilic methanotroph. It specifically digests single-stranded DNA in the 3ʹ to 5ʹ direction. The protein is composed of 479 amino acids, and it shares 47% sequence identity with E. coli Exo I. The crystal structure of MszExo I was determined to a resolution of 2.2 Å and it aligns well with that of E. coli Exo I. Comparative studies revealed that MszExo I and E. coli Exo I have similar metal ion binding affinity and similar activity at mesophilic temperatures (25–47°C). However, the optimum working temperature of MszExo I is 10°C higher, and the melting temperature is more than 4°C higher as evaluated by both thermal inactivation assays and DSC measurements. More importantly, two thermal transitions during unfolding of MszExo I were monitored by DSC while only one transition was found in E. coli Exo I. Further analyses showed that magnesium ions not only confer structural stability, but also affect the unfolding of MszExo I. MszExo I is the first reported enzyme in the DNA repair systems of moderately thermophilic bacteria, which are predicted to have more efficient DNA repair systems than mesophilic ones.     

Stability-enhanced Hot-melt Extruded Amorphous Solid Dispersions via Combinations of Soluplus? and HPMCAS-HF

The aim of this study was to evaluate a novel combination of Soluplus® and hypromellose acetate succinate (HPMCAS-HF) polymers for solubility enhancement as well as enhanced physicochemical stability of the produced amorphous solid dispersions. This was accomplished by converting the poorly water-soluble crystalline form of carbamazepine into a more soluble amorphous form within the polymeric blends. Carbamazepine (CBZ), a Biopharmaceutics Classification System class II active pharmaceutical ingredient (API) with multiple polymorphs, was utilized as a model drug. Hot-melt extrusion (HME) processing was used to prepare solid dispersions utilizing blends of polymers. Drug loading showed a significant effect on the dissolution rate of CBZ in all of the tested ratios of Soluplus® and HPMCAS-HF. CBZ was completely miscible in the polymeric blends of Soluplus® and HPMCAS-HF up to 40% drug loading. The extrudates were characterized by differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and dissolution studies. DSC and XRD data confirmed the formation of amorphous solid dispersions of CBZ in the polymeric blends of Soluplus® and HPMCAS-HF. Drug loading and release of CBZ was increased with Soluplus® (when used as the primary matrix polymer) when formulations contained Soluplus® with 7–21% (w/w) HPMCAS-HF. In addition, this blend of polymers was found to be physically and chemically stable at 40°C, 75% RH over 12 months without any dissolution rate changes.KEY WORDS: carbamazepine, hot-melt extrusion, HPMCAS-HF, Soluplus®, stability     

Hydrolysis of fibrous cotton and reprecipitated cellulose by cellulolytic enzymes from soil micro-organisms

1. The catalytic decomposition of undegraded cellulose in the form of cotton fibres is described with hydrogen peroxide at 0·4–0·04% (w/v) concentration in the presence of ferrous salts at pH3–5. 2. Complete solubilization of 5mg. of cotton fibres occurred in about 7 days in the presence of 0·4% hydrogen peroxide and 0·2mm-ferrous sulphate at the optimum pH4·2–4·3. 3. With 0·4% hydrogen peroxide the most rapid decomposition of cellulose was confined to ferrous sulphate concentrations of approx. 2–0·02mm. If the concentrations of the reagents were decreased in proportion extensive breakdown occurred but much more slowly. 4. In the primary stages of breakdown cotton fibres were disintegrated to very short fibres. These were subsequently solubilized, but there was little accumulation of soluble material. Organic matter was lost from solution as the reaction progressed. 5. Other naturally occurring cellulose-containing materials, such as grass, straw, hay and sawdust, were also disintegrated and solubilized by hydrogen peroxide and ferrous sulphate.     

Decomposition of Organic Carbon in Fine Soil Particles Is Likely More Sensitive to Warming than in Coarse Particles: An Incubation Study with Temperate Grassland and Forest Soils in Northern China

It is widely recognized that global warming promotes soil organic carbon (SOC) decomposition, and soils thus emit more CO₂ into the atmosphere because of the warming; however, the response of SOC decomposition to this warming in different soil textures is unclear. This lack of knowledge limits our projection of SOC turnover and CO₂ emission from soils after future warming. To investigate the CO₂ emission from soils with different textures, we conducted a 107-day incubation experiment. The soils were sampled from temperate forest and grassland in northern China. The incubation was conducted over three short-term cycles of changing temperature from 5°C to 30°C, with an interval of 5°C. Our results indicated that CO₂ emissions from sand (>50 µm), silt (2–50 µm), and clay (<2 µm) particles increased exponentially with increasing temperature. The sand fractions emitted more CO₂ (CO₂-C per unit fraction-C) than the silt and clay fractions in both forest and grassland soils. The temperature sensitivity of the CO₂ emission from soil particles, which is expressed as Q₁₀, decreased in the order clay>silt>sand. Our study also found that nitrogen availability in the soil facilitated the temperature dependence of SOC decomposition. A further analysis of the incubation data indicated a power-law decrease of Q₁₀ with increasing temperature. Our results suggested that the decomposition of organic carbon in fine-textured soils that are rich in clay or silt could be more sensitive to warming than those in coarse sandy soils and that SOC might be more vulnerable in boreal and temperate regions than in subtropical and tropical regions under future warming.     

Medical management of the acute radiation syndrome

The acute radiation syndrome (ARS) occurs after whole-body or significant partial-body irradiation (typically at a dose of >1 Gy). ARS can involve the hematopoietic, cutaneous, gastrointestinal and the neurovascular organ systems either individually or in combination.There is a correlation between the severity of clinical signs and symptoms of ARS and radiation dose. Radiation induced multi-organ failure (MOF) describes the progressive dysfunction of two or more organ systems over time. Radiation combined injury (RCI) is defined as radiation injury combined with blunt or penetrating trauma, burns, blast, or infection. The classic syndromes are: hematopoietic (doses >2–3 Gy), gastrointestinal (doses 5–12 Gy) and cerebrovascular syndrome (doses 10–20 Gy). There is no possibility to survive after doses >10–12 Gy.The Phases of ARS are—prodromal: 0–2 days from exposure, latent: 2–20 days, and manifest illness: 21–60 days from exposure.Granulocyte-colony stimulating factor (G-CSF) at a dose of 5 μg/kg body weight per day subcutaneously has been recommended as treatment of neutropenia, and antibiotics, antiviral and antifungal agents for prevention or treatment of infections.If taken within the first hours of contamination, stable iodine in the form of nonradioactive potassium iodide (KI) saturates iodine binding sites within the thyroid and inhibits incorporation of radioiodines into the gland.Finally, if severe aplasia persists under cytokines for more than 14 days, the possibility of a hematopoietic stem cell (HSC) transplantation should be evaluated.This review will focus on the clinical aspects of the ARS, using the European triage system (METREPOL) to evaluate the severity of radiation injury, and scoring groups of patients for the general and specific management of the syndrome.     

Harmonization of the Volume of Interest Delineation among All Eleven Radiotherapy Centers in the North of France

Background

Inter-observer delineation variation has been detailed for many years in almost every tumor location. Inadequate delineation can impair the chance of cure and/or increase toxicity. The aim of our original work was to prospectively improve the homogeneity of delineation among all of the senior radiation oncologists in the Nord-Pas de Calais region, irrespective of the conditions of practice.

Methods

All 11 centers were involved. The first studied cancer was prostate cancer. Three clinical cases were studied: a low-risk prostate cancer case (case 1), a high-risk prostate cancer case (pelvic nodes, case 2) and a case of post-operative biochemical elevated PSA (case 3). All of the involved physicians delineated characteristically the clinical target volume (CTV) and organs at risk. The volumes were compared using validated indexes: the volume ratio (VR), common and additional volumes (CV and AV), volume overlap (VO) and Dice similarity coefficient (DSC). A second delineation of the same three cases was performed after discussion of the slice results and the choice of shared guidelines to evaluate homogenization. A comparative analysis of the indexes before and after discussion was conducted using the Wilcoxon test for paired samples. A p-value less than 0.05 was considered to indicate statistical significance.

Results

The indexes were not improved in case 1, for which the inter-observer agreement was considered good after the first comparison (DSC = 0.83±0.06). In case 2, the second comparison showed homogenization of the CTV delineation with a significant improvement in CV (81.4±11.7 vs. 88.6±10.26, respectively, p = 0.048), VO (0.41±0.09 vs. 0.47±0.07, respectively; p = 0.009) and DSC (0.58±0.09 vs. 0.63±0.07, respectively; p = 0.0098). In case 3, VR and AV were significantly improved: VR: 1.71(±0.6) vs. 1.34(±0.46), respectively, p = 0.0034; AV: 46.58(±14.50) vs. 38.08(±15.10), respectively, p = 0.0024. DSC was not improved, but it was already superior to 0.6 in the first comparison.

Conclusion

Our prospective work showed that a collaborative discussion about clinical cases and the choice of shared guidelines within an established framework improved the homogeneity of CTV delineation among the senior radiation oncologists in our region.     

Adaptation of Phytoplankton-Degrading Microbial Communities to Thermal Reactor Effluent in a New Cooling Reservoir

In water column and sediment inocula from a nuclear reactor cooling reservoir, natural phytoplankton substrate labeled with ¹⁴C was used to determine aerobic and anaerobic mineralization rates for a range of temperatures (25, 40, 55, and 70°C) expected during reactor operation. For experiments that were begun during reactor shutdown, aerobic decomposition occurred at temperatures of <55°C. After 2 months of reactor operation, aerobic rates increased substantially at 55 and 70°C, although maximum rates were observed at temperatures of ≤40°C. The temperature range for which maximum anaerobic mineralization (i.e., the sum of CH₄ and CO₂) was observed was 25 to 40°C when the reactor was off, expanding to 25 to 55°C during reactor operation. Increased rates at 55°C, but not 70°C, correlated with an increase in the ratio of cumulative methane to carbon dioxide produced over 21 days. When reduced reactor power lowered the maximum temperature of the reservoir to 42°C, aerobic decomposition at 70°C was negligible, but remained substantial at 55°C. Selection for thermophilic decomposers occurred rapidly in this system in both aerobic and anaerobic communities and did not require prolonged exposure to elevated temperatures.     

Partially Disordered Structure in Intravirus Coat Protein of Potyvirus Potato Virus A

Potyviruses represent the most biologically successful group of plant viruses, but to our knowledge, this work is the first detailed study of physicochemical characteristics of potyvirus virions. We measured the UV absorption, far and near UV circular dichroism spectra, intrinsic fluorescence spectra, and differential scanning calorimetry (DSC) melting curves of intact particles of a potato virus A (PVA). PVA virions proved to have a peculiar combination of physicochemical properties. The intravirus coat protein (CP) subunits were shown to contain an unusually high fraction of disordered structures, whereas PVA virions had an almost normal thermal stability. Upon heating from 20°C to 55°C, the fraction of disordered structures in the intravirus CP further increased, while PVA virions remained intact at up to 55°C, after which their disruption (and DSC melting) started. We suggest that the structure of PVA virions below 55°C is stabilized by interactions between the remaining structured segments of intravirus CP. It is not improbable that the biological efficiency of PVA relies on the disordered structure of intravirus CP.     

Antimicrobial Effects of Ionizing Radiation on Artificially and Naturally Contaminated Cacao Beans

With an initial microbial level of ca. 10⁷ microorganisms per g of Ivory Coast cacao beans, 5 kGy of gamma radiation under an atmosphere of air reduced the microflora per g by 2.49 and 3.03 logs at temperatures of 35 and 50°C, respectively. Bahia cacao beans were artificially contaminated with dried spores of Aspergillus flavus and Penicillium citrinum, giving initial fungal levels of 1.9 × 10⁴ and 1.4 × 10³ spores per g of whole Bahia cacao beans, respectively. The average D₁₀ values for A. flavus and P. citrinum spores on Bahia cacao beans were 0.66 and 0.88 kGy, respectively.