Amount Of 14C Research Articles

Assessment of annual emissions of 14C isotopes at nuclear power plants and their impact on the radiation dose of the population and plants

The necessity of controlling emissions of carbon – 14 (14C) isotope into the atmosphere during the operation of a nuclear power plant is substantiated. It is determined that the main negative effect of the carbon isotope 14C has on humans and animals. Plants are less susceptible to this influence. A method for measuring the emission into the atmosphere of 14C is proposed. The analysis of various studies on the amount of 14C emissions at various nuclear power plants was carried out. The calculation of the amount of carbon isotope 14C is performed. The annual radiation dose of the population from the release of 14C was estimated. Various options for reducing the amount of 14C in emissions at nuclear power plants are considered.

METABOLISMS OF 13C IN CATTLE SEMITENDINOSUS MUSCLE AFTER ADMINISTRATION OF 13C LABELED ORCHARD GRASS.

14C released from nuclear facilities is transferred to cattle through their consumption of 14C contaminated grasses. To estimate the concentrations of 14C in their meat, we conducted two sets of experiments. In the first experiment, 230mg of 13C per day was administered to cattle aged 10months for 28days in the form of 13C-labeled grass. The 13C concentration in the semitendinosus muscle decreased exponentially after reaching its peak value. The mean half-life was 76±13days. In the second experiment, 550mg of 13C per day was administered to 24-month-old cattle. The change in the semitendinosus muscle was smaller than that recorded in the first experiment, even though the amount of 13C administered per body weight was slightly higher than that in the first experiment. Consequently, the half-life was not determined. Therefore, further studies are required to clarify the metabolism of carbon in 2-year-old cattle.

Fatty acids composition and health indices in different fat and muscle locations of lambs from crossbreeding between Lori-Bakhtiari and Romanov sheep breeds

The current study aimed to evaluate the fatty acids (FAs) profile of five different locations in pure Lori-Bakhtiari (LL genotype) fat-tailed sheep and their crosses (RL genotype) with the Romanov-tailed breed. After slaughtering, samples were collected from longissimus thoracis (LT) and semi-membranous (SM) as muscle, and fat-tail (FT), subcutaneous (SC), and abdominal (AB) fat as adipose tissues. After extracting the ether extract of samples according to the recommendations by the AOAC, the fatty acid composition of the samples was determined using gas chromatography. The main FAs were C14:0, C16:0, C18:0, and C18:1 for all locations. These FAs accounted for about 80–88 % and 85–90 % of the total FAs in muscle and adipose tissues, respectively. The results showed that for many of the FAs in muscle tissues, there were no significant differences between the LL and RL genotypes; However, the genotypes had a significant difference in proportions of C14, C16:1, C18:0, C18:3, C20:0, and C20:1 (P < 0.05) in all locations, as the LL genotype had lower C18:0 and C20:0 than the RL genotype.Genotypes did not show significant differences in classic ratios and health indices in muscle tissues and AB fat; While in FT and SC tissues, the genotypes had significant differences regarding saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), the unsaturated fatty acid to saturated fatty acid ratio (U/S), the saturation index (SI), and the trombogenic index (TI). The comparison of fatty acids and indices between muscle (LT and SM) and adipose (FT, SC, and AB) tissues showed that these two tissues were statistically different in terms of many individual fatty acids and indices (P < 0.05; P < 0.01). Also, adipose tissues had different amounts of C12:0 (0.22 vs. 0.45), C15:0 (0.82 vs. 0.36), C16:0 (26.51 vs. 27.73), C16:1 (3.37 vs. 2.75), C17:1 (1.29 vs. 0.49), C18:1c (39.05 vs. 43.80), C18: 1 t (1.57 vs. 0.76), C18: 2n6 (3.15 vs. 3.86), and C20:1 (0.84 vs. 0.58).The n-6/n-3 and h/H ratios were significant difference between fat and muscle tissues (P < 0.05). it can be concluded that RL genotype was not superior than the LL genotype regarding the FAs, the ratios, and health indices. Therefore, crossbreeding native fat-tailed Lori-Bakhtiari sheep with Romanov sheep does not improve the meat quality; however, it can decrease the total body fat content.

Segmental cervical instability does not drive the loss of cervical lordosis after laminoplasty in patients with cervical spondylotic myelopathy

BACKGROUND/CONTEXTKyphotic deformity after cervical laminoplasty (CLP) often leads to unfavorable neurological recovery due to insufficient indirect decompression of the spinal cord. Existing literature has described that segmental cervical instability is a contraindication for CLP because it is a potential risk factor for kyphotic changes after surgery; however, this has never been confirmed in any clinical studies. PURPOSETo confirm whether segmental cervical instability was an independent risk factor for postoperative kyphotic change and to examine whether segmental cervical instability led to poor neurological outcomes after CLP for cervical spondylotic myelopathy (CSM). STUDY DESIGN/SETTINGA retrospective study PATIENT SAMPLEPatients who underwent CLP for CSM between January 2013 and January 2021 with a follow-up period of ≥1 year were enrolled. OUTCOME MEASURESCervical radiographic measurements including C2–C7 lordosis (C2–7 angle), cervical sagittal vertical axis, C7 slope, flexion range of motion (fROM) and extension ROM (eROM) were assessed using neutral and flexion-extension views. Segmental cervical instability was classified into anterolisthesis (AL) of ≥2 mm displacement, retrolisthesis (RL) of ≥2 mm displacement, and translational instability (TI) of ≥3 mm translational motion. The amount of C2–7 angle loss at the follow-up period compared to the preoperative measurements was defined as cervical lordosis loss (CLL). Neurological outcomes were assessed using the recovery rate of the Japanese Orthopedic Association score (JOA-RR). METHODSCLL was compared among patients with and without segmental cervical instability. Further, multiple linear regression model for CLL was built for the evaluation with adjustment of the reported risks, including cervical sagittal vertical axis, C7 slope, fROM, eROM, and patient age together with AL, RL, and TI, as independent variables. The JOA-RR was also compared between patients with and without segmental cervical instability. RESULTSA total of 138 patients (mean age, 68.7 years; 65.9% male) were included in the analysis. AL, RL, and TI were found in 12 (8.7%), 33 (23.9%), and 16 (11.6%) patients, respectively. Comparisons among the groups showed that AL led to greater CLL; however, RL and TI did not. Multiple linear regression analysis revealed that greater CLL is significantly associated with greater fROM and smaller eROM (regression coefficient [β]=0.328, 95% confidence interval: 0.178 to 0.478, p<.001; β=−0.372, 95% confidence interval: −0.591 to −0.153, p=.001, respectively). However, there were no significant statistical associations in the AL, RL, and TI. Whereas, patients with AL tended to exhibit lower JOA-RR than those without AL (37.8% vs. 52.0%, p=.108). CONCLUSIONSSegmental cervical instability is not the definitive driver for loss of cervical lordosis after CLP in patients with CSM; thus, is not a contraindication in and of itself. However, it is necessary to consider the indications for CLP, according to individual cases of patients with AL on baseline radiograph, which is a sign of poor neurological recovery.

Valorization of Hazardous Organic Solid Wastes towards Fuels and Chemicals via Fast (Catalytic) Pyrolysis

The management of municipal and industrial organic solid wastes has become one of the most critical environmental problems in modern societies. Nowadays, commonly used management techniques are incineration, composting, and landfilling, with the former one being the most common for hazardous organic wastes. An alternative eco-friendly method that offers a sustainable and economically viable solution for hazardous wastes management is fast pyrolysis, being one of the most important thermochemical processes in the petrochemical and biomass valorization industry. The objective of this work was to study the application of fast pyrolysis for the valorization of three types of wastes, i.e., petroleum-based sludges and sediments, residual paints left on used/scrap metal packaging, and creosote-treated wood waste, towards high-added-value fuels, chemicals, and (bio)char. Fast pyrolysis experiments were performed on a lab-scale fixed-bed reactor for the determination of product yields, i.e., pyrolysis (bio)oil, gases, and solids (char). In addition, the composition of (bio)oil was also determined by Py/GC-MS tests. The thermal pyrolysis oil from the petroleum sludge was only 15.8 wt.% due to the remarkably high content of ash (74 wt.%) of this type of waste, in contrast to the treated wood and the residual paints (also containing 30 wt.% inorganics), which provided 46.9 wt.% and 35 wt.% pyrolysis oil, respectively. The gaseous products ranged from ~7.9 wt.% (sludge) to 14.7 (wood) and 19.2 wt.% (paints), while the respective solids (ash, char, reaction coke) values were 75.1, 35, and 36.9 wt.%. The thermal (non-catalytic) pyrolysis of residual paint contained relatively high concentrations of short acrylic aliphatic ester (i.e., n-butyl methacrylate), being valuable monomers in the polymer industry. The use of an acidic zeolitic catalyst (ZSM-5) for the in situ upgrading of the pyrolysis vapors induced changes on the product yields (decreased oil due to cracking reactions and increased gases and char/coke), but mostly on the pyrolysis oil composition. The main effect of the ZSM-5 zeolite catalyst was that, for all three organic wastes, the catalytic pyrolysis oils were enriched in the value-added mono-aromatics (BTX), especially in the case of the treated wood waste and residual paints. The non-condensable gases were mostly consisting of CO, CO2, and different amounts of C1–C4 hydrocarbons, depending on initial feed and use or not of the catalyst that increased the production of ethylene and propylene.

Release of 3H and 14C during sampling and speciation in activated concrete

Characterisation of contaminated and activated decommissioning waste require sampling of the studied material for the analysis of different radionuclides. The volatility of 3H and 14C can lead to the loss of the analytes in sampling of solid materials since most often at least some heat is involved in the sampling technique. Especially 3H can be lost in cases when it is present as tritiated water (HTO) due to the evaporation of water even at low temperatures. Therefore, in this study, the 3H and 14C speciations are discussed. Consequently, a drilling sampling technique was developed in order to capture the released 3H and 14C in absorption solutions and measured using liquid scintillation counting. The sampling technique was tested on an activated concrete core. The collected samples were analysed for 3H and 14C (activity concentration and speciation) using a thermal oxidation technique. The results showed that a significant amount of 3H was released during sampling even though the majority of 3H was strongly bound in the activated concrete. The studied activated concrete did not contain measurable amount of 14C and therefore speciation studies were not possible.

МЕТОДИЧЕСКИЕ ПОДХОДЫ К МОНИТОРИНГУ УГЛЕРОДА-14 ДЛЯ КОНТРОЛЯ ЕГО РАДИАЦИОННОГО ВОЗДЕЙСТВИЯ НА ПЕРСОНАЛ И НАСЕЛЕНИЕ

Purpose: Analysis of the current regulatory and methodological framework on control of doses from intake of 14C for the personnel and the public living in the control area of the nuclear power plant (NPP). Identifying the most informative methods of controlling radiation impact of 14C on a human being. Material and methods: Research literature on radiation impact of naturally occurring 14C; 14C entering the environment as a result of nuclear weapon tests; and 14C entering workplaces and the control area of NPP has been reviewed. Dose coefficients and other radiation characteristics of 14C provided in IAEA, ICRP and UNSCEAR publications have been summarized. Results: According to UNSCEAR, annual radiation burden caused by global 14C is the highest one (about 80 %) among radiation burdens associated with four critical naturally occurring cosmogenic radionuclides: 3H (0.01 µSv/year), 7Be (3.0 µSv/year), 14C (12 µSv/year) and 24Na (0.2µSv/year). The main way of 14C intake is the alimentary one when this isotope enters the human body with food. Dose from this kind of intake of global 14C can reach 40 µSv. The annual dose caused by aerogenic (inhalation) way of intake of global 14C does not exceed 1 µSv. The most informative methods of dose assessment for the personnel of NPP and the public living in the control area involve measurement of content of 14C in top soil, vegetation and food products. Conclusions: Significant amount of 14C enters the environment within the control area during operation of NPP, which causes the public radiation dose exceeding the dose from global 14C. The most informative objects characterizing content of technogenic 14C in the control area of NPP are top soil (humus) and vegetation. The liquid scintillation spectrometry involves sample preparation by burning of samples in oxygen with capturing of generated carbon dioxide and its transfer into organic solvent. This is the most technologically viable method for mass control of 14C content in samples of top soil and vegetation.

Belowground allocation and dynamics of recently fixed plant carbon in a California annual grassland

Plant roots and the organisms that surround them are a primary source for stabilized soil organic carbon (SOC). While grassland soils have a large capacity to store organic carbon (C), few field-based studies have quantified the amount of plant-fixed C that moves into soil and persists belowground over multiple years. Yet this characteristic of the soil C cycle is critical to C storage, soil water holding capacity, nutrient provisions, and the management of soil health. We tracked the fate of plant-fixed C following a five-day 13CO2 labeling of a Northern California annual grassland, measuring C pools starting at the end of the labeling period, at three days, four weeks, six months, one year, and two years. Soil organic carbon was fractionated using a density-based approach to separate the free-light fraction (FLF), occluded-light fraction (OLF), and heavy fraction (HF). Using isotope ratio mass spectrometry, we measured 13C enrichment and total C content for plant shoots, roots, soil, soil dissolved organic carbon (DOC), and the FLF, OLF, and HF. The chemical nature of C in the HF was further analyzed by solid state 13C nuclear magnetic resonance (NMR) spectroscopy.At the end of the labeling period, a substantial portion of the 13C (40%) was already found belowground in roots, soil, and soil DOC. By 4 weeks, the highest isotope enrichment and 27% of the total amount of 13C remaining in the system was associated with the mineral-rich HF. At the 6-month sampling—after the dry summer period during which plants senesced and died—the amount of label in the FLF increased to an amount similar to that in the HF. The FLF 13C then declined substantially by 1 year and further decreased in the second year. By the end of the 2-year experiment, 67% of remaining label was in the HF, with 19% in the FLF and 14% in the OLF. While the 13C content in the HF was stable over the final year, the chemical forms associated with the HF evolved with time. The relative proportion of aliphatic/alkyl C functional groups declined in the newly formed SOC over the 2 years in the field; simultaneously, aromatic and carbonyl/carboxylic C functional groups increased and the proportion of carbohydrate (O-alkyl C) groups remained relatively constant.Our results indicate that plant-fixed C moved into soil within days of its fixation and was associated with the soil mineral fraction within weeks. While most of the annual plant C input in these grasslands cycles rapidly (<2-year timescale), a sizeable proportion (about 23% of the 13C present at day 0) persisted in the soil for longer than 2 years. While decadal studies would allow improved assessment of the long-term stabilization of newly fixed plant C, our 2-year field study reveals surprisingly rapid movement of plant C into the HF of soil, followed by subsequent evolution of the chemical forms of organic C in the HF.

64 Feeding Chicory-plantain Silage and Se-yeast on Lactating Ewe Subjected to Intramammary Infection: Effect on Performance and Milk Quality

Abstract Our objective was to test the effect on milk yield and quality of feeding a combination of chicory-plantain and Se-yeast in lactating ewes subjected to intramammary infection (IMI). For this purpose, we enrolled 28 Polypay ewes from a prior study where they received chicory (CS) or grass (GC) silage and supplemented with 3.6 mg of Se/day as Se-yeast (DiaMune, Diamond V) (Y) or not (C) for 2 months. For the present study, ewes were kept on the original dietary regiment except the CS group received a chicory-plantain silage (50% each). Ewes were milked twice daily and milk was collected for analysis of components and somatic cell count (SCC). IMI was induced by injecting 2×107 CFU of Strep. uberis in both glands. Data were analyzed using GLIMMIX (SAS) with time, silage, and Se and their interactions as the fixed effects and ewe as random effect with significance declared P ≤ 0.05. SCC increased 8-fold 24h post-IMI and remained at that level until the end of the experiment with higher values pre-IMI in GC-Y animals but no difference post-IMI. Milk yield drastically decreased post-IMI but was not affected by treatments. Protein, fat, solids, amount of de novo fatty acids, and amount of C16:0 were larger in milk of ewes fed chicory-plantain compared to grass silage. Supplementation of Se had minor effect on milk components with a tendency (P = 0.07) to decrease fat, solids, and amount of de novo fatty acids. Amounts of C18:0, C18:1, and preformed fatty acids in milk were increased by Se supplementation in ewes fed grass while decreased in ewes fed chicory. The use of Strep. uberis was effective in inducing IMI in ewes with chicory-plantain improving several milk components while Se supplementation had minor effects. The combination of chicory and Se did not improve the response to IMI.

A FRAMEWORK FOR TRANSDISCIPLINARY RADIOCARBON RESEARCH: USE OF NATURAL-LEVEL AND ELEVATED-LEVEL 14C IN ANTARCTIC FIELD RESEARCH

ABSTRACTRadiocarbon (14C) is an isotopic tracer used to address a wide range of scientific research questions. However, contamination by elevated levels of 14C is deleterious to natural-level laboratory workspaces and accelerator mass spectrometer facilities designed to precisely measure small amounts of 14C. The risk of contaminating materials and facilities intended for natural-level 14C with elevated-level 14C-labeled materials has dictated near complete separation of research groups practicing profoundly different measurements. Such separation can hinder transdisciplinary research initiatives, especially in remote and isolated field locations where both natural-level and elevated-level radiocarbon applications may be useful. This paper outlines the successful collaboration between researchers making natural-level 14C measurements and researchers using 14C-labeled materials during a subglacial drilling project in West Antarctica (SALSA 2018–2019). Our strict operating protocol allowed us to successfully carry out 14C labeling experiments within close quarters at our remote field camp without contaminating samples of sediment and water intended for natural level 14C measurements. Here we present our collaborative protocol for maintaining natural level 14C cleanliness as a framework for future transdisciplinary radiocarbon collaborations.

Lipid metabolism of sea urchin Paracentrotus lividus in two contrasting natural habitats

Sea urchins Paracentrotus lividus were harvested monthly from April 2015 to March 2016 from two sites in Sardinia (Italy). The two sites, a Posidonia oceanica meadow and a rocky bottom habitat, were naturally characterized by different food sources and availability, being mainly populated by the sea grass Posidonia oceanica and the brown algae Halopteris scoparia, respectively. Total lipids showed a minimum during winter in mature gonads, and a maximum in the summer (recovery stage). Fatty acid (FA) profiles of gut contents and gonads differed from those of the most available food sources. Levels of C18:3 (n-3) (ALA) discriminated samples from the two sites. Despite the very low amounts of C20:5 (n-3) (EPA) and C20:4 (n-6) (ARA) in P. oceanica, the main FA in gonads and gut contents were EPA and ARA in both sites. Increase in green algae intake prior to gametogenesis, especially C. cylindracea, likely affected EPA and ARA levels in gonads. The results show that P. lividus is able to concentrate lipids in gut contents and also to selectively store EPA, ARA and their precursors ALA and 18:2 (n-6) (LA). Moreover, bioconversion of ALA to EPA and of LA to ARA in P. lividus is suggested.

Dietary Supplementation with Camelina sativa (L. Crantz) Forage in Autochthonous Ionica Goats: Effects on Milk and Caciotta Cheese Chemical, Fatty Acid Composition and Sensory Properties.

Simple SummaryCamelina sativa (L. Cranz), commonly known as false flax, is an annual dicot species belonging to the Brassicaceae family. The plant is characterised by extreme rusticity and is able to grow in different climatic and soil conditions, including those of the Southern Italy marginal areas. Camelina is studied as a sustainable crop for food and non-food exploitation. Its interest in animal nutrition is due to the fatty acid (FA) composition of its oil, high in polyunsaturated FA (PUFA). This study aimed to evaluate the effect of dietary supplementation with Camelina sativa fresh forage in autochthonous goats on the chemical composition and fatty acid profile of milk and Caciotta cheese, a traditional short-term ripened cheese with a soft ivory-coloured rind, compact texture, semi-soft paste, acid fermented odour, and delicate sweet taste. The milk from the Camelina group showed a greater content of conjugated linoleic acid (CLA) and PUFA, with benefits for human health. Under the nutritional point of view, Caciotta cheeses were similar between the two groups, but the recruited panellists appreciated the cheese obtained from the Camelina group more for its better palatability.The research studied the effects of dietary supplementation with Camelina sativa fresh forage on the chemical and fatty acid composition of milk and Caciotta cheese, and its sensory properties. Twenty Ionica goats were randomly assigned to the following two groups (n = 10): the control received a traditional forage mixture (Avena sativa, 70%; Vicia sativa, 20%; Trifolium spp., 10%), while the experimental group was given Camelina sativa fresh forage (CAM). All of the dams grazed on pasture and received a commercial feed (500 g/head/day) at housing. The milk from the CAM group showed a higher (p < 0.05) content of dry matter, fat, lactose and concentrations of C6:0, C11:0, C14:0, C18:2 n-6, CLA and PUFA, while lower (p < 0.05) amounts of C12:0, C18:0 and saturated long chain FA (SLCFA). The Caciotta cheese from the CAM group showed a greater (p < 0.05) content of n-6 FA and n-6/n-3 ratio, although close to four, thus resulting adequate under the nutritional point of view. The overall liking, odour, taste, hardness, solubility and “goaty” flavour were better (p < 0.05) in the CAM cheeses. Further investigation would be advisable in order to evaluate the effect of feeding Camelina forage obtained from different phenological stages, and the application of ensiling techniques.

Organic fertilization affects carbon assimilation and partitioning of nonbearing potted strawberry plants

The decline of soil fertility due to intensification of agricultural practice can lead to reduced plant performances; the use of organic amendments could be a valuable strategy to overcome this this problem. The aim of the present study was to verify that the application of organic fertilizers may promote root growth to the detriment of the canopy by evaluating the effects of application of organic fertilizer on CO2 fixation, C partitioning, and plant growth. The experiment was carried out on strawberry (Fragaria × ananassa) plants, potted in 10 L pots. The following treatments were compared, in a complete randomized block design: (1) unfertilized control; (2) mineral fertilization; (3) cow manure (20 g kg−1 soil); (4) compost low rate (20 g kg−1 soil); (5) compost high rate (60 g kg−1 soil). Two months after their application, fertilizers did not affect plant growth; however, the application of compost at the high rate stimulated the 13CO2 assimilation. In the following 2 weeks, plants treated with compost at 60 g kg−1 soil showed a higher amount of 13C than the other treatments; however, the 13C relative partitioning was not affected by fertilization. Root:canopy ratio was decreased by mineral and compost high rate fertilizations, in response to the increase of root N concentration, indicating that root growth was stimulated by low soil N.

Lower microbial carbon use efficiency reduces cellulose-derived carbon retention in soils amended with compost versus mineral fertilizers

Cellulose decomposition is a key process in soil carbon (C) cycling due to the high abundance of cellulose in plant biomass. Microbial functional groups that sequester C from cellulose, and the accumulation of cellulose C in soil aggregates, remains debated. We hypothesized that cellulose derived 13C would be more efficiently converted into soil organic C by microorganisms, and retained in soil subjected to long-term application of compost. In this study, soil sampled from a long-term (27 years) field experiment with application of compost (Compost), NPK fertilizers (NPK) and without fertilizers (control), was incubated with 13C-cellulose for 120 days. The cellulose 13C content, microbial community structure (lipid biomarkers) and microbial 13C use efficiency (CUE) were measured. The incorporation of 13C into large macroaggregates (>2000 μm), small macroaggregates (250–2000 μm), microaggregates (53–250 μm), and silt + clay fraction (<53 μm) was analyzed to elucidate cellulose 13C sequestration process in aggregates. In contrast to our initial hypothesis, 13C remaining in soil after 120 days of incubation was maximal in unfertilized soil (25%) and minimal in Compost soil (17%). Compost soil had higher abundance of fungi and especially fast-growing bacteria (Gram-negative (G–) bacteria) than NPK and control soils. This accelerated decomposition and lowered CUE of 13C, therefore reducing the amount of 13C remaining in the Compost soil. In contrast, in the other soils, the lower fungal abundance reduced cellulose decomposition, which in turn contributed to growth of Gram-positive (G+) bacteria characterized by larger CUE than G– bacteria. This increased the ratio of G+/G– bacteria, resulting in larger CUE and more 13C remaining in NPK and control soils. Cellulose-derived 13C content decreased in small macroaggregates and microaggregates for all three soils, and in silt + clay fraction for the Compost soil; meanwhile, cellulose-derived 13C content increased in the silt + clay fraction for NPK and control soils from day 14 onwards. The ratios of 13C content in small macroaggregates and microaggregates to that in silt + clay fraction were higher in NPK and unfertilized soils than in Compost soil during the incubation. This indicated that less 13C was redistributed from large aggregates to silt + clay fraction in Compost soil. Overall, cellulose was more rapidly decomposed and incorporated into aggregates in organic C-rich soil, but their transformation efficiency into soil organic C was lower than in organic C-poor soil.

Soluble Fiber Inulin Consumption Limits Alterations of the Gut Microbiota and Hepatic Fatty Acid Metabolism Caused by High-Fat Diet.

Diet shapes the gut microbiota which impacts hepatic lipid metabolism. Modifications in liver fat content are associated with metabolic disorders. We investigated the extent of dietary fat and fiber-induced alterations in the composition of gut microbiota and hepatic fatty acids (FAs). Mice were fed a purified low-fat diet (LFD) or high-fat diet (HFD) containing non-soluble fiber cellulose or soluble fiber inulin. HFD induced hepatic decreases in the amounts of C14:0, C16:1n-7, C18:1n-7 and increases in the amounts of C17:0, C20:0, C16:1n-9, C22:5n-3, C20:2n-6, C20:3n-6, and C22:4n-6. When incorporated in a LFD, inulin poorly affected the profile of FAs. However, when incorporated in a HFD, it (i) specifically led to an increase in the amounts of hepatic C18:0, C22:0, total polyunsaturated FAs (PUFAs), total n-6 PUFAs, C18:3n-3, and C18:2n-6, (ii) exacerbated the HFD-induced increase in the amount of C17:0, and (iii) prevented the HFD-induced increases in C16:1n-9 and C20:3n-6. Importantly, the expression/activity of some elongases and desaturases, as well as the gut microbiota composition, were impacted by the dietary fat and fiber content. To conclude, inulin modulated gut microbiota and hepatic fatty acid composition, and further investigations will determine whether a causal relationship exists between these two parameters.

Newly assimilated carbon allocation in grassland communities under different grazing enclosure times

The flow of photosynthesized carbon (C) from plants to soil and its loss from the respiration in the soil-plant system were measured via in situ 13CO2 pulse labeling pasture in overgrazed and long-term grazing exclosures (where grazing was not permitted for 5, 10, and 30 years). During a 30-day chase period, the allocation of newly assimilated C in the shoots, roots, and soil of grazing-excluded grasslands was higher than that in overgrazed grasslands. But the newly assimilated C allocated to shoots and soil respiration in overgrazed grasslands was significantly higher than that in grazing-excluded grasslands. Thirty days after labeling, 35% and 40% of the newly assimilated C in overgrazed grasslands were lost through shoots and soil respiration, respectively. The shoot 13C recovery was 32% in the 30 years 30 days after labeling, which was significantly higher than that obtained at the 5 and 10 years exclosure sites. Root and soil 13C recoveries in the 5- and 10-year exclosures were higher than those at the 30-year sites. In the grazing-excluded grasslands, the amount of 13C in soil organic C peaked 3 days after 13CO2 exposure and became relatively stable after 19 days of assimilation. The mean C residence time for non-structural C used in the soil respiration under overgrazing (10 days) was shorter than that under 5- (20 days) and 10- (17 days) or 30-year exclosures (14 days). Compared to overgrazing, grazing exclosure, especially moderate grazing exclosure, led to more allocation of newly assimilated C in the plant-soil system but fewer allocation in shoots and soil respiration.

Symmetries of 13C tracer deposition in EAST D and He plasmas investigated on the sub-mm to 100 mm scale by deuteron nuclear reaction analysis

In continuation of an earlier study, this work focusses on deposit analysis in the mm region around the tracer injection hole of two 13CD4 injection experiments in EAST by using focussed 1.43 MeV deuteron ion beam analysis. This study adds ∼1500 data points to the former work on the same samples to assess more details on deposition patterns and symmetry and test the accuracy of former extrapolations.Mapping of the 13CD4 injection-hole vicinity using 0.2 mm lateral resolution yields compatible results as the former 1.8 mm resolution for the local co-deposit thickness. The new data reveal the deposition maximum to be 1 ± 0.2 mm away from the injection hole towards the ExB direction, resembling the triangular shape also seen on the larger scale. The analysis of 3 blocks along the magnetic field vector shows a dominant deposition along the surface area closest to the last closed flux surface. An edge with a factor ∼11 drop in deposit thickness within 2 mm spans here along the whole 150 mm tile size and along the axis of the magnetic field. The analysis using proton backscattering shows no He retention in the He plasma exposed co-deposits above the 1 % limit of detection.The total deposited 13C amount was underestimated by ∼5 % in the former study, a value not exceeding the measurement uncertainty. The combination of ∼0.2 mm spatial resolution around the injection-hole and at the deposit edge with ∼ 2 mm resolution but larger coverage outside these regions is found to provide a reasonable compromise of information quality and analysis effort.

Evaluating the Glacial‐Deglacial Carbon Respiration and Ventilation Change Hypothesis as a Mechanism for Changing Atmospheric CO2

AbstractThe prevailing hypothesis to explain pCO2 rise at the last glacial termination calls upon enhanced ventilation of excess respired carbon that accumulated in the deep sea during the glacial. Recent studies argue lower [O2] in the glacial ocean is indicative of increased carbon respiration. The magnitude of [O2] depletion was 100–140 µ mol/kg at the glacial maximum. Because respiration is coupled to δ13C of dissolved inorganic carbon (DIC), [O2] depletion of 100–140 µ mol/kg from carbon respiration would lower deep water δ13CDIC by ∼1‰ relative to surface water. Prolonged sequestration of respired carbon would also lower the amount of 14C in the deep sea. We show that Pacific Deep Water δ13CDIC did not decrease relative to the surface ocean and Δ14C was only ∼50‰ lower during the late glacial. Model simulations of the hypothesized ventilation change during deglaciation lead to large increases in δ13CDIC, Δ14C, and ε14C that are not recorded in observations.

Fate and behavior of 14C-labelled ionic compounds in a soil simulation test

The influence of an ionic functional group on the fate and behavior of chemicals in the environment has so far not been systematically investigated. This study, therefore, examines the following three substances with high structural similarity but differing charge: non-charged 4-n-dodecylphenol[phenylring-14C(U)] (14C-DP), negatively charged 4-n-dodecylbenzenesulfonicacid[phenylring-14C(U)] sodium salt (14C-DS−) and positively charged 4-n-dodecylbenzyltrimethylammonium chloride[phenylring-14C(U)] (14C-DA+). They were investigated in a soil simulation study according to the OECD 307 test guideline by measuring the distribution of the applied radioactivity (AR) among volatile, mineralized, extractable and non-extractable residues (NER) in one soil after 0, 1, 7, 14, 49, 84 and 124 days of incubation. Extractable portions of 14C were examined by means of radio-TLC and -HPLC analyses. Microbial activity of the soil incubated with and without 14C-DP, 14C-DS− and 14C-DA+ was determined measuring the reduction of dimethylsulfoxide (DMSO) over time. After 124 days of incubation highest mineralization could be observed for 14C-DS− (64.5% AR). Except CO2, no volatile residues were formed over time. Besides the parent compounds, polar (14C-DP, 14C-DS− and 14C-DA+) and nonpolar (14C-DA+) transformation products were detected. Highest amounts of 14C were extracted using methanol and were thus potentially bioavailable for soil microorganisms. Microbial activity was markedly higher in soil incubated with 14C-DP and 14C-DS− compared to 14C-DA+ or soil without any treatment. Half-lives (DT50 k2) at 18 °C were as follows: DA+ (61.8 days) > DS− (18.2 days) > DP (10.0 days). In case of the cationic compound and its transformation products we conclude that a higher sorption affinity to soil particles leads to reduced bioavailability for microorganisms and thus reduced mineralization resulting in a higher persistence compared to anionic and non-charged organic compounds in soil. The impact of our findings on the persistence assessment of chemicals when performing OECD guideline tests in soil, water-sediment and surface water is discussed.

Sensitivity of Osteosarcoma Cells to Concentration-Dependent Bioactivities of Lipid Peroxidation Product 4-Hydroxynonenal Depend on Their Level of Differentiation.

4-Hydroxynonenal (HNE) is a major aldehydic product of lipid peroxidation known to exert several biological effects. Normal and malignant cells of the same origin express different sensitivity to HNE. We used human osteosarcoma cells (HOS) in different stages of differentiation in vitro, showing differences in mitosis, DNA synthesis, and alkaline phosphatase (ALP) staining. Differentiated HOS cells showed decreased proliferation (3H-thymidine incorporation), decreased viability (thiazolyl blue tetrazolium bromide-MTT), and increased apoptosis and necrosis (nuclear morphology by staining with 4′,6-diamidino-2-phenylindole-DAPI). Differentiated HOS also had less expressed c-MYC, but the same amount of c-FOS (immunocytochemistry). When exposed to HNE, differentiated HOS produced more reactive oxygen species (ROS) in comparison with undifferentiated HOS. To clarify this, we measured HNE metabolism by an HPLC method, total glutathione (GSH), oxidized GSH (ox GSH), glutathione transferase activity (GST), proteasomal activity by enzymatic methods, HNE-protein adducts by genuine ELISA and fatty acid composition by GC-MS in these cell cultures. Differentiated HOS cells had less GSH, lower HNE metabolism, increased formation of HNE-protein adducts, and lower proteasomal activity, in comparison to undifferentiated counterpart cells, while GST and oxGSH were the same. Fatty acids analyzed by GC-MS showed that there is an increase in C20:3 in differentiated HOS while the amount of C20:4 remained the same. The results showed that the cellular machinery responsible for protection against toxicity of HNE was less efficient in differentiated HOS cells. Moreover, differentiated HOS cells contained more C20:3 fatty acid, which might make them more sensitive to free radical-initiated oxidative chain reactions and more vulnerable to the effects of reactive aldehydes such as HNE. We propose that HNE might act as natural promotor of decay of malignant (osteosarcoma) cells in case of their differentiation associated with alteration of the lipid metabolism.