Preparation and characterization of activated carbon from sunflower seed oil residue via microwave assisted K2CO3 activation

Sunflower seed oil residue, a by-product of sunflower seed oil refining, was utilized as a feedstock for preparation of activated carbon (SSHAC) via microwave induced K(2)CO(3) chemical activation. SSHAC was characterized by Fourier transform infrared spectroscopy, nitrogen adsorption-desorption and elemental analysis. Surface acidity/basicity was examined with acid-base titration, while the adsorptive properties of SSHAC were quantified using methylene blue (MB) and acid blue 15 (AB). The monolayer adsorption capacities of MB and AB were 473.44 and 430.37 mg/g, while the Brunauer-Emmett-Teller surface area, Langmuir surface area and total pore volume were 1411.55 m(2)/g, 2137.72 m(2)/g and 0.836 cm(3)/g, respectively. The findings revealed the potential to prepare high surface area activated carbon from sunflower seed oil residue by microwave irradiation.     

2-Steps KOH activation of rice straw: An efficient method for preparing high-performance activated carbons

Effects of both pre-treatment and number of steps in KOH activation of raw rice straw (RS) on textural and adsorption properties of RS-derived activated carbons (ACs) were investigated. Three pre-treatment protocols were tested: mechanical, chemical by NaOH pulping, and a combination of both. Activation of RS-based materials was investigated, at a constant temperature of 800 °C, according to two ways: a 1-step simultaneous carbonisation–activation with KOH, and a 2-steps process: carbonisation followed by activation by KOH.     

Microwave-assisted preparation and adsorption performance of activated carbon from biodiesel industry solid reside: influence of operational parameters

Preparation of activated carbon has been attempted using KOH as activating agent by microwave heating from biodiesel industry solid residue, oil palm empty fruit bunch (EFBAC). The significance of chemical impregnation ratio (IR), microwave power and activation time on the properties of activated carbon were investigated. The optimum condition has been identified at the IR of 1.0, microwave power of 600 W and activation time of 7 min. EFBAC was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and nitrogen adsorption isotherm. The surface chemistry was examined by zeta potential measurement, determination of surface acidity/basicity, while the adsorptive property was quantified using methylene blue as dye model compound. The optimum conditions resulted in activated carbon with a monolayer adsorption capacity of 395.30 mg/g and carbon yield of 73.78%, while the BET surface area and total pore volume were corresponding to 1372 m²/g and 0.76 cm³/g, respectively.     

Preparation and characterization of activated carbon from palm shell by chemical activation with K2CO3

Palm shell was used to prepare activated carbon using potassium carbonate (K2CO3) as activating agent. The influence of carbonization temperatures (600-1000 degrees C) and impregnation ratios (0.5-2.0) of the prepared activated carbon on the pore development and yield were investigated. Results showed that in all cases, increasing the carbonization temperature and impregnation ratio, the yield decreased, while the adsorption of CO2 increased, progressively. Specific surface area of activated carbon was maximum about 1170 m2/g at 800 degrees C with activation duration of 2 h and at an impregnation ratio of 1.0.     

Comparison between entrapment methods for phenol removal and operation of bioreactor packed with co-entrapped activated carbon and Pseudomonas fluorescence KNU417

A microorganism capable of degrading phenol was isolated from crude oil contaminated soil and identified as Pseudomonas fluorescence. A porous polymer bead of polyvinyl alcohol (PVA) and Xanthan gum was found to be the best entrapment for phenol degradation in terms of bead shape (spherical form), bead strength, non-agglomeration, phenol degradation rate, and cell holding inside the bead. Activated carbon was co-immobilized with the microorganism in the bead, which readily adsorbed phenol to decrease initial phenol concentration. Due to the decreased phenol concentration, the cells needed shorter adaptation time after which the microorganism stably degraded phenol. When the bead containing microorganism with 1% of activated carbon was packed in a packed-bed bioreactor, the start-up period was shortened by 40 h and the removal efficiency of phenol during the period was increased by 28% than the case with only microorganism.     

The fate of photosynthetically-fixed carbon in Lolium perenne grassland as modified by elevated CO2 and sward management

Prediction of the impact of climate change requires the response of carbon (C) flow in plant-soil systems to increased CO(2) to be understood. A mechanism by which grassland C sequestration might be altered was investigated by pulse-labelling Lolium perenne swards, which had been subject to CO(2) enrichment and two levels of nitrogen (N) fertilization for 10 yr, with (14)CO(2). Over a 6-d period 40-80% of the (14)C pulse was exported from mature leaves, 1-2% remained in roots, 2-7% was lost as below-ground respiration, 0.1% was recovered in soil solution, and 0.2-1.5% in soil. Swards under elevated CO(2) with the lower N supply fixed more (14)C than swards grown in ambient CO(2), exported more fixed (14)C below ground and respired less than their high-N counterparts. Sward cutting reduced root (14)C, but plants in elevated CO(2) still retained 80% more (14)C below ground than those in ambient CO(2). The potential for below-ground C sequestration in grasslands is enhanced under elevated CO(2), but any increase is likely to be small and dependent upon grassland management.     

积雪和冻结土壤系统中的微生物碳排放和碳氮循环的季节性特征

土壤微生物作为生态系统中重要的分解者,在对动植物残体以及土壤有机质降解的过程中,一方面释放CO2到大气中,是土壤碳排放的重要组成部分;另一方面,在分解的过程中,形成了可供给植物利用的无机养分.由于温度对代谢活动的直接影响,过去对微生物代谢的研究主要集中在生长季,通常假设冬季土壤微生物的活力可以忽略.陆地表面近60％的区域经历着季节性积雪覆盖和季节性土壤冻结的影响.近年来的研究表明,由于积雪的覆盖,形成很好的绝缘层,雪被下土壤中微生物仍然具有显著的活性,对土壤碳排放和植物的养分吸收具有重要的贡献.本文就积雪和冻结土壤系统中的微生物碳排放和碳氮循环的季节性特征进行了全面的分析,综述了国内外冬季雪下碳氮循环的研究现状,提出了目前研究中存在的问题和未来的研究方向,强调了开展温带冬季雪下土壤微生物碳氮循环研究的必要性和重要性.     

Supercritical CO2 as a reaction medium for synthesis of capsaicin analogues by lipase-catalyzed transacylation of capsaicin

Capsaicin analogues having different acyl moiety were synthesized by lipase-catalyzed transacylation of capsaicin with a corresponding acyl donor in supercritical CO₂ as a reaction medium. Transacylation with methyl tetradecanoate using Novozym 435 as a catalyst gave vanillyl tetradecanamide in a 54% yield at 80 °C and 19 MPa over 72 h. Vanillyl (Z)-9-octadecenamide, olvanil, was synthesized from triolein in a 21% yield over 7 d.     

Enhancement of rice canopy carbon gain by elevated CO(2) is sensitive to growth stage and leaf nitrogen concentration

Increasing our understanding of the factors regulating seasonal changes in rice canopy carbon gain (C(gain): daily net photosynthesis -- night respiration) under elevated CO(2) concentrations ([CO(2)]) will reduce our uncertainty in predicting future rice yields and assist in the development of adaptation strategies. In this study we measured CO(2) exchange from rice (Oryza sativa) canopies grown at c. 360 and 690 micromol mol(-1)[CO(2)] in growth chambers continuously over three growing seasons. Stimulation of C(gain) by elevated [CO(2)] was 22-79% during vegetative growth, but decreased to between -12 and 5% after the grain-filling stage, resulting in a 7-22% net enhancement for the whole season. The decreased stimulation of C(gain) resulted mainly from decreased canopy net photosynthesis and partially from increased respiration. A decrease in canopy photosynthetic capacity was noted where leaf nitrogen (N) decreased. The effect of elevated [CO(2)] on leaf area was generally small, but most dramatic under ample N conditions; this increased the stimulation of whole-season C(gain). These results suggest that a decrease in C(gain) enhancement following elevated CO(2) levels is difficult to avoid, but that careful management of nitrogen levels can alter the whole-season C(gain) enhancement.     

Decomposability of C3 and C4 grass litter sampled under different concentrations of atmospheric carbon dioxide at a natural CO2 spring

Elevated concentrations of atmospheric CO₂ can influence the relative proportions, biomass and chemical composition of plant species in an ecosystem and, thereby, the input of litter nutrients to soil. Plant growth under elevated CO₂ appears to have no consistent effect on rates of litter decomposition; decomposition can, however, differ in C3 and C4 plant material from the same CO₂ environment. We here describe the decomposability of leaf litter of two grass species – the C3 Holcus lanatus L. (Yorkshire fog) and C4 Pennisetum clandestinum Hochst. (kikuyu) - from an unfertilized, ungrazed grassland at a cold CO₂ spring in Northland, New Zealand. Decomposability was measured by net CO₂–C production from litter incubated for 56 days at 25 °C in a gley soil from the site; net mineral-N production from litter was also determined. Both litter and soils were sampled under `low' and `high' concentrations of atmospheric CO₂. Decomposition of H. lanatus litter was greater than that of P. clandestinum litter throughout the 56-day incubation. Decomposition tended to be greater in `high-CO<sub>2</sub>' than in `low-CO₂' H. lanatus litter, but lower in `high-CO<sub>2</sub>' than `low-CO₂' P. clandestinum litter; differences were, however, non-significant after 28 days. Overall, litter decomposition was greater in the `low-CO<sub>2</sub>' than `high-CO₂' soil. Differences in decomposition rates were related negatively to litter N concentrations and positively to C:N ratios, but were not predictable from lignin:total N ratios. Net mineral-N production from litter decomposition did not differ significantly in `high-CO<sub>2</sub>' and `low-CO₂' samples incubated in `low-CO<sub>2</sub>' soil; in `high-CO₂' soil some net immobilization was observed. Overall, results indicate the likely complexity of litter decomposition in the field but, nevertheless, strongly suggest that rates of decomposition will not necessarily decline in a `high-CO₂' environment.     

Real-time dissolved carbon dioxide monitoring I: Application of a novel in situ sensor for CO2 monitoring and control

Dissolved carbon dioxide (dCO₂) is a well-known critical parameter in bioprocesses due to its significant impact on cell metabolism and on product quality attributes. Processes run at small-scale faces many challenges due to limited options for modular sensors for online monitoring and control. Traditional sensors are bulky, costly, and invasive in nature and do not fit in small-scale systems. In this study, we present the implementation of a novel, rate-based technique for real-time monitoring of dCO₂ in bioprocesses. A silicone sampling probe that allows the diffusion of CO₂ through its wall was inserted inside a shake flask/bioreactor and then flushed with air to remove the CO₂ that had diffused into the probe from the culture broth (sensor was calibrated using air as zero-point calibration). The gas inside the probe was then allowed to recirculate through gas-impermeable tubing to a CO₂ monitor. We have shown that by measuring the initial diffusion rate of CO₂ into the sampling probe we were able to determine the partial pressure of the dCO₂ in the culture. This technique can be readily automated, and measurements can be made in minutes. Demonstration experiments conducted with baker's yeast and Yarrowia lipolytica yeast cells in both shake flasks and mini bioreactors showed that it can monitor dCO₂ in real-time. Using the proposed sensor, we successfully implemented a dCO₂-based control scheme, which resulted in significant improvement in process performance.     

Effect of grazing on carbon stocks and assimilate partitioning in a Tibetan montane pasture revealed by 13CO2 pulse labeling

Since the late 1950s, governmental rangeland policies have changed the grazing management on the Tibetan Plateau (TP). Increasing grazing pressure and, since the 1980s, the privatization and fencing of pastures near villages has led to land degradation, whereas remote pastures have recovered from stronger overgrazing. To clarify the effect of moderate grazing on the carbon (C) cycle of the TP, we investigated differences in below‐ground C stocks and C allocation using in situ ¹³CO₂ pulse labeling of (i) a montane Kobresia winter pasture of yaks, with moderate grazing regime and (ii) a 7‐year‐old grazing exclosure plot, both in 3440 m asl. Twenty‐seven days after the labeling, ¹³C incorporated into shoots did not differ between the grazed (43% of recovered ¹³C) and ungrazed (38%) plots. In the grazed plots, however, less C was lost by shoot respiration (17% vs. 42%), and more was translocated below‐ground (40% vs. 20%). Within the below‐ground pools, <2% of ¹³C was incorporated into living root tissue of both land use types. In the grazed plots about twice the amount of ¹³C remained in soil (18%) and was mineralized to CO₂ (20%) as compared to the ungrazed plots (soil 10%; CO₂ 9%). Despite the higher contribution of root‐derived C to CO₂ efflux, total CO₂ efflux did not differ between the two land use types. C stocks in the soil layers 0–5 and 5–15 cm under grazed grassland were significantly larger than in the ungrazed grassland. However, C stocks below 15 cm were not affected after 7 years without grazing. We conclude that the larger below‐ground C allocation of plants, the larger amount of recently assimilated C remaining in the soil, and less soil organic matter‐derived CO₂ efflux create a positive effect of moderate grazing on soil C input and C sequestration.     

Hot-water spraying is a sensitive test for signs of life before dressing and scalding in pig abattoirs with carbon dioxide (CO2) stunning

This study investigated the benefits of hot-water spraying (HWS) as a diagnostic test to verify the absence of signs of life (SOL) before scalding in pigs slaughtered with carbon dioxide (CO₂) stunning. A total of 37 108 finishing pigs from five German abattoirs (A to E) operating at 55 to 571 pigs per hour were assessed. Suspended pigs were sprayed onto the muzzle, head and front legs (143 to 258 s post sticking for 4 to 10 s, 57°C to 72°C). Any active movements during HWS were rated as positive test outcomes. In comparison, SOL were considered to be absent if a subsequent manual examination was negative and no active movements were observed following HWS. The incidence of pigs with activity during hot-water spraying (PWA) was restricted to two abattoirs (B: 0.25%; D: 0.02%; A, C, E: 0.00%). PWA showed movements of facial muscles (88%), mouth opening (78%), righting reflex (63%), isolated leg movements (35%) and vocalization (4%). The manual examination was positive in 71% of PWA (corneal/dazzle reflex: 67%/53%, nasal septum pinch: 33%), whereas all inactive pigs tested negative (P<0.001). The sensitivity for HWS as a test for SOL was calculated as 100%, dropping to 75% when only obvious and strong movements were taken into account. The specificity was >99.9% in either case. Any positive manual findings as well as any respiratory activity were instantly terminated using a penetrating captive bolt. Active movements triggered by the shot were shown to be an indicator for SOL (P<0.001). Video analyses revealed that spontaneous movements (SM) following sticking were present in 100% of PWA as opposed to 3.1% in pigs without such activity (controls). Results for different categories of SM in PWA v. controls were as follows: 100% v. 2.6% for mouth opening, 16.0% v. 0.1% for righting reflex and 22.0% v. 0.9% for isolated leg movements (all P<0.001). First mouth opening after sticking was observed later in PWA (28±24 v. 10±7 s), but mouth openings were observed for a longer period of time (141±44 v. 27±25 s) (both P<0.001). PWA with shorter mouth-opening intervals showed higher movement intensities during HWS and more positive manual findings (P<0.05). We conclude that HWS is a promising test for SOL. SM and sustained mouth opening in particular are indicators for compromised animal welfare and affected pigs should be shot by captive bolt.     

Effects of increased atmospheric CO2, temperature,and soil N availability on root exudation of dissolved organic carbon by a N-fixing tree (Robinia pseudoacacia L.)

Root exudation has been hypothesized as one possible mechanism that may lead to increased inputs of organic C into the soil under elevated atmospheric CO₂, which could lead to greater long-term soil C storage. In this study, we analyzed exudation of dissolved organic C from the roots of seedlings of the N-fixing tree Robinia pseudoacacia L. in a full factorial design with 2 CO₂ (35.0 and 70.0 Pa) × 2 temperature (26° and 30 °C during the day) × 2 N fertilizer (0 and 10.0 mM N concentration) levels. We also analyzed the decomposition rates of root exudate to estimate gross rates of exudation. Elevated CO₂ did not affect root exudation of organic C. A 4 °C increase in temperature and N fertilization did, however, significantly increase organic C exudation rates. Approximately 60% of the exudate decomposed relatively rapidly, with a turnover rate of less than one day, while the remaining 40% decomposed more slowly. These results suggest that warmer climates, as predicted for the next century, may accelerate root exudation of organic C, which will probably stimulate rapid C cycling and may make a minor contribution to intermediate to more long-term soil C storage. However, as these losses to root exudation did not exceed 1.2% of the net C fixed by Robinia pseudoacacia, root exudation of organic C appears to have little potential to contribute to long-term soil C sequestration. This revised version was published online in June 2006 with corrections to the Cover Date.     

Rabbit muscle aldolase (RAMA) as a catalyst in a new approach for the synthesis of 3-deoxy-D-manno-2-octulosonic acid and analogues

A new approach leading to 3-deoxy-D-manno-2-octulosonic acid (KDO) and 4-deoxy-KDO is described. The key step is the formation of the C₅---C₆ bond catalysed by fructose-1,6-bisphosphate aldolase, which controls the stereochemistry of these two centres. The important step of the aldehyde substrates (1a, 1b, 1c) synthesis is the Barbier reaction of ethyl-bromomethylacrylate or bromomethylacrylonitrile with the monoacetal of glyoxal in the presence of indium.     

Preparation,statistical optimization and characterization of poly(3-hydroxybutyrate) fermented by Cupriavidus necator utilizing various hydrolysates of alligator weed (Alternanthera philoxeroides) as a sole carbon source

Alligator weed (Alternanthera philoxeroides) is a stoloniferous, amphibious and perennial herb which has invaded many parts of the world and led to serious environmental and ecological problems. In order to exploit cheap carbon source for poly(3-hydroxybutyrate) (PHB) production, alligator weed hydrolysates were prepared by acid and enzyme treatment and used for PHB production via Cupriavidus necator. The bacterium utilized alligator weed enzymatic hydrolysate and produced the PHB concentration of 3.8 ± 0.2 g/L at the conditions of pH 7.0, 27.5°C, 1.5 g/L of nitrogen source, and 25 g/L of carbon source, this exceeded the value of 2.1 ± 0.1 g/L from acid hydrolysate media at the same conditions. In order to obtain the optimum conditions of PHB production, response surface methodology was employed which improved PHB content. The optimum conditions for PHB production are as follows: carbon source, 34 g/L; nitrogen source, 2 g/L; pH, 7; temperature, 28°C. After 72 hr of incubation, the bacterium produced 8.5 g/L of dry cell weight and 4.8 g/L of PHB. The PHB was subjected to Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and Molecular weight analysis and found the melting temperature, number average molecular mass, and polydispersity were 168.20°C, 185 kDa, and 2.1, respectively.     

The carbon fertilization effect over a century of anthropogenic CO2 emissions: higher intracellular CO2 and more drought resistance among invasive and native grass species contrasts with increased water use efficiency for woody plants in the US Southwest

From 1890 to 2015, anthropogenic carbon dioxide emissions have increased atmospheric CO₂ concentrations from 270 to 400 mol mol^?1. The effect of increased carbon emissions on plant growth and reproduction has been the subject of study of free‐air CO₂ enrichment (FACE) experiments. These experiments have found (i) an increase in internal CO₂ partial pressure (c_i) alongside acclimation of photosynthetic capacity, (ii) variable decreases in stomatal conductance, and (iii) that increases in yield do not increase commensurate with CO₂ concentrations. Our data set, which includes a 115‐year‐long selection of grasses collected in New Mexico since 1892, is consistent with an increased c_i as a response to historical CO₂ increase in the atmosphere, with invasive species showing the largest increase. Comparison with Palmer Drought Sensitivity Index (PDSI) for New Mexico indicates a moderate correlation with Δ¹³C (r² = 0.32, P < 0.01) before 1950, with no correlation (r² = 0.00, P = 0.91) after 1950. These results indicate that increased c_i may have conferred some drought resistance to these grasses through increased availability of CO₂ in the event of reduced stomatal conductance in response to short‐term water shortage. Comparison with C₃ trees from arid environments (Pinus longaeva and Pinus edulis in the US Southwest) as well as from wetter environments (Bromus and Poa grasses in New Mexico) suggests differing responses based on environment; arid environments in New Mexico see increased intrinsic water use efficiency (WUE) in response to historic elevated CO₂ while wetter environments see increased c_i. This study suggests that (i) the observed increases in c_i in FACE experiments are consistent with historical CO₂ increases and (ii) the CO₂ increase influences plant sensitivity to water shortage, through either increased WUE or c_i in arid and wet environments, respectively.     

The effect of dexamethasone on polyclonal T cell activation and redirected target cell lysis as induced by a CD19/CD3-bispecific single-chain antibody construct

BiTE molecules comprise a new class of bispecific single-chain antibodies redirecting previously unstimulated CD8+ and CD4+ T cells for the elimination of target cells. One example is MT103 (MEDI-538; bscCD19xCD3), a CD19-specific BiTE that can induce lysis of normal and malignant B cells at low picomolar concentrations, which is accompanied by T cell activation. Here, we explored in cell culture the impact of the glucocorticoid derivative dexamethasone on various activation parameters of human T cells in response to MT103. In case cytokine-related side effects should occur with BiTE molecules and other T cell-based approaches during cancer therapy it is important to understand whether glucocorticoids do interfere with the cytotoxic potential of T cells. We found that MT103 induced in the presence of target cells secretion by peripheral T cells of interleukin (IL)-2, tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), IL-6, IL-10 and IL-4 into the cell culture medium. Production of all studied cytokines was effectively reduced by dexamethasone at a concentration between 1 and 3x10(-7) M. In contrast, upregulation of activation markers CD69, CD25, CD2 and LFA-1 on both CD4+ and CD8+ T cells, and T cell proliferation were barely affected by the steroid hormone analogue. Most importantly, dexamethasone did not detectably inhibit the cytotoxic activity of MT103-activated T cells against a human B lymphoma line as investigated with lymphocytes from 12 human donors. Glucocorticoids thus qualify as a potential co-medication for therapeutic BiTE molecules and other cytotoxic T cell therapies for treatment of cancer.     

Characterization of porous poly(D,L-lactic-co-glycolic acid) sponges fabricated by supercritical CO2 gas-foaming method as a scaffold for three-dimensional growth of Hep3B cells

This study presents the application of the porous poly(D,L-lactic-co-glycolic acid) (PLGA) sponges fabricated from an organic solvent free supercritical gas foaming technique. Two formulations of PLGA sponges with different co-polymer compositions (85:15 and 50:50) were fabricated as novel scaffolds to guide human hepatoma cell line, Hep3B cell growth in vitro. The PLGA sponges showed desirable biodegradability and exhibited uniform pore size distribution with moderate interconnectivity. It was observed in this study that cells cultured on PLGA sponges showed lower proliferation rate as compared to the control during 14 days of culture as measured by using total DNA and methylthiazol tetrazolium (MTT) assays. However, the cells cultured on the sponges tended to aggregate to form cell islets which were able to express better hepatic functions. The enzyme-linked immunosorbent assay (ELISA) results showed that the cell-sponge constructs secreted 1.5-3.0 times more albumin than the control when normalized to cellular content. In a similar fashion, its detoxification ability was also predominantly higher than that of the control as indicated by the ethoxyresorufin-O-deethylase (EROD) results. By comparing the cells growing on the two formulations of PLGA sponges, it was found that the PLGA 85:15 sponge exhibited better conductive and desirable environment for hep3B cells as justified by better cell infiltration, higher proliferation and hepatic function than the PLGA 50:50 sponge.