Comparison of ammonium lactate, sodium bicarbonate and double calcium lactate methods for extraction of phosphorus from wetland peat soils

Procedures for routine analysis of soil phosphorus (P) have been used for assessment of P status, distribution and P losses from cultivated mineral soils. No similar studies have been carried out on wetland peat soils. The objective was to compare extraction efficiency of ammonium lactate (PAL), sodium bicarbonate (P-Olsen), and double calcium lactate (P-DCaL) and P distribution in the soil profile of wetland peat soils. For this purpose, 34 samples of the 0-30, 30-60 and 60-90 cm layers were collected from peat soils in Germany, Israel, Poland, Slovenia, Sweden and the United Kingdom and analysed for P. Mean soil pH (CaCl2, 0.01 M) was 5.84, 5.51 and 5.47 in the 0-30, 30-60 and 60-90 cm layers, respectively. The P-DCaL was consistently about half the magnitude of either P-AL or P-Olsen. The efficiency of P extraction increased in the order P-DCaL < P-AL &LE; P-Olsen, with corresponding means (mg kg(-1)) for all soils (34 samples) of 15.32, 33.49 and 34.27 in 0-30 cm; 8.87, 17.30 and 21.46 in 30-60 cm; and 5.69, 14.00 and 21.40 in 60-90 cm. The means decreased with depth. When examining soils for each country separately, P-Olsen was relatively evenly distributed in the German, UK and Slovenian soils. P-Olsen was linearly correlated (r = 0.594, P = 0.0002) with pH, whereas the three P tests (except P-Olsen vs P-DCaL) significantly correlated with each other (P = 0.017850.0001). The strongest correlation (r = 0.617, P = 0.0001) was recorded for P-AL vs P-DCaL) and the two methods were inter-convertible using a regression equation: P-AL = -22.593 + 5.353 pH + 1.423 P-DCaL, R-2 = 0.550.

A comparison of energy use in conventional and integrated arable farming systems in the UK

The LINK Integrated Farming Systems (LINK-IFS) Project (1992-1997) was setup to compare conventional and integrated arable farming systems (IAFS), concentrating on practical feasibility and economic viability, but also taking into account the level of inputs used and environmental impact. As part of this, an examination into energy use within the two systems was also undertaken. This paper presents the results from that analysis. The data used is from the six sites within the LINK-IFS Project, spread through the arable production areas of England and from the one site in Scotland, covering the 5 years of the project. The comparison of the energy used is based on the equipment and inputs used to produce I kg of each crop within the conventional and integrated rotations, and thereby the overall energy used for each system. The results suggest that, in terms of total energy used, the integrated system appears to be the most efficient. However, in terms of energy efficiency, energy use per kilogram of output, the results are less conclusive. (C) 2003 Elsevier Science B.V. All rights reserved.

Comparison of methane produced by straw fed sheep in open-circuit respiration with methane predicted by fermentation characteristics measured by an in vitro gas procedure

Reducing carbon conversion of ruminally degraded feed into methane increases feed efficiency and reduces emission of this potent greenhouse gas into the environment. Accurate, yet simple, predictions of methane production of ruminants on any feeding regime are important in the nutrition of ruminants, and in modeling methane produced by them. The current work investigated feed intake, digestibility and methane production by open-circuit respiration measurements in sheep fed 15 untreated, sodium hydroxide (NaOH) treated and anhydrous ammonia (NH3) treated wheat, barley and oat straws. In vitro fermentation characteristics of straws were obtained from incubations using the Hohenheim gas production system that measured gas production, true substrate degradability, short-chain fatty acid production and efficiency of microbial production from the ratio of truly degraded substrate to gas volume. In the 15 straws, organic matter (OM) intake and in vivo OM digestibility ranged from 563 to 1201 g and from 0.464 to 0.643, respectively. Total daily methane production ranged from 13.0 to 34.4 l, whereas methane produced/kg OM matter apparently digested in vivo varied from 35.0 to 61.8 l. The OM intake was positively related to total methane production (R2 = 0.81, P<0.0001), and in vivo OM digestibility was also positively associated with methane production (R2 = 0.67, P<0.001), but negatively associated with methane production/kg digestible OM intake (R2 = 0.61, P<0.001). In the in vitro incubations of the 15 straws, the ratio of acetate to propionate ranged from 2.3 to 2.8 (P<0.05) and efficiencies of microbial production ranged from 0.21 to 0.37 (P<0.05) at half asymptotic gas production. Total daily methane production, calculated from in vitro fermentation characteristics (i.e., true degradability, SCFA ratio and efficiency of microbial production) and OM intake, compared well with methane measured in the open-circuit respiration chamber (y = 2.5 + 0.86x, R2 = 0.89, P<0.0001, Sy.x = 2.3). Methane production from forage fed ruminants can be predicted accurately by simple in vitro incubations combining true substrate degradability and gas volume measurements, if feed intake is known.

In vitro evaluation of fibrolytic enzymes as additives for maize (Zea mays L.) silage - III. Comparison of enzymes derived from psychrophilic, mesophilic or thermophilic sources

A completely randomised study was completed to examine the influence of fibrolytic enzymes derived from psychrophilic, (F), mesophilic, (L) or thermophilic (Ta) sources, applied at ensiling, on the chemical characteristics and in vitro rumen fermentation of maize silage, assessed using the Reading Pressure Technique (RPT). Treatments, all in triplicate, consisted of untreated maize forage or treated with preparations F, L, Ta or a mixture (1: 1, v/v) of F and L (FL), at two levels each, and ensiled for 210 days in plastic mini-silos. Addition of enzymes L decreased (P < 0.05) silage pH relative to the control, whereas enzyme Ta tended (P < 0.10) to reduce it. Preparations F, L and Ta tended to reduce (P < 0.10) the fibre contents of the silages, with effects being attributable to a decrease in the cellulose fraction. Starch contents were reduced (P < 0.05) in the treatments including enzyme F. End-point (96 h) gas production (GP) values did not differ among treatments, suggesting that enzymes did not change the total amount of fermentable substrate. However, consistent with the decrease in starch contents, adding enzyme F reduced (P < 0.05) GP at most incubation times. Addition of enzymes increased (P < 0.05) the initial (6 h) organic matter degradation (OMD) levels in all but one treatment (F), with increases of 14, 19, and 26% for preparations L, Ta, and FL, respectively, averaged across levels. Furthermore, the addition of enzymes increased (P < 0.05) the soluble OM losses, however, these increases did not fully account for the initial increase in OMD. The latter suggests that enzymes increased solubility and also altered silage structure, making it more amenable to degradation by ruminal microorganisms. As a result of the increase in OMD, without a concomitant increase in GP, the fermentation efficiency was greatly increased (P < 0.05) in enzyme treatments. Addition of enzymes to maize at ensiling, particularly those from the mesophilic and thermophilic sources used here, have the potential to increase the initial rate of silage OMD. (C) 2003 Elsevier B.V. All rights reserved.

Comparison of white metal and resin socket terminations for wire ropes

Previously the authors have presented both theoretical and experimental work discussing the operating mechanism of a wire rope held in a tapered socket by means of a cast resin cone. The work reported here extends the investigation to address the question of whether the same socket fabricated with white metal operates in the same manner. To date, previous investigations have compared the operational efficiency of resin and white metal in terms of both strength and/or fatigue endurance. Some other work has analysed the operation of resin sockets or specific cast metal terminations. This paper seeks to draw the results from this work together, and, in addition to a theoretical analysis, presents experimental data obtained from a direct comparison of the operation mechanism for the same sockets filled with resin or white metal. Results show that white metal terminations have a very different distribution of stresses along the length of the socket basket from resin terminations, and a smaller but still significant amount of socket draw. For both types of termination the socket draw develops high frictional gripping forces which can transfer the load from the rope to the socket. The different stress distributions mean that the consequences of termination fabrication defects may not be the same for resin and white metal terminations.

Stubs versus swabs? A comparison of gunshot residue collection techniques

The collection efficiency of two widely used gunshot residue (GSR) collection techniques—carbon-coated adhesive stubs and alcohol swabs—has been compared by counting the number of characteristic GSR particles collected from the firing hand of a shooter after firing one round. Samples were analyzed with both scanning electron microscopy and energy dispersive X-rays by an experienced GSR analyst, and the number of particles on each sample containing Pb, Ba, and Sb counted. The adhesive stubs showed a greater collection efficiency as all 24 samples gave positive results for GSR particles whereas the swabs gave only positive results for half of the 24 samples. Results showed a statistically significant collection efficiency for the stub collection method and likely reasons for this are considered.

A comparison of the anticancer properties of isoxanthohumol and 8-prenylnaringenin using in vitro models of colon cancer

The hops plant (Humulus lupulus L.) is an essential ingredient in beer and contains a number of potentially bioactive prenylflavonoids, the predominant being the weakly estrogenic isoxanthohumol (Ix), which can be converted to the more strongly estrogenic 8-PN by the colonic microbiota. The aim of this study was to investigate the biological activity of 8-PN and Ix using in vitro models representing key stages of colorectal carcinogenesis, namely cell growth and viability (MTT assay), cell-cycle progression (DNA content assay), DNA damage (Comet assay), and invasion (Matrigel assay). A significant decrease in Caco-2 cell viability was noted after both 8-PN and Ix treatments at the higher doses (40 and 50 μM, respectively) although the impact on cell cycle differed between the two compounds. The decreased cell viability observed after Ix treatment was associated with a concentration-dependent increase in G2/M and an increased sub-G1 cell-cycle fraction, whereas treatment with 8-PN was associated with an elevated G0/G1 and an increased sub-G1 cell-cycle fraction. Significant antigenotoxic activity was noted at all 8-PN concentrations tested (5-40 μM). Although significant antigenotoxic activity was also noted with Ix treatment at ≤25 μM, at a higher dose, Ix itself exerted genotoxic activity. In a dose-dependent manner, both compounds inhibited HT115 cell invasion with reductions up to 52 and 46% for Ix and 8-PN, respectively, in comparison to untreated cells. This study demonstrated that both Ix and its gut microbial metabolite 8-PN exert anticancer effects on models of key stages of colon tumourigenesis.

A comparison of the Thlaspi caerulescens and Thlaspi arvense shoot transcriptomes

Whole-genome transcriptome profiling is revealing how biological systems are regulated at the transcriptional level. This study reports the development of a robust method to profile and compare the transcriptomes of two nonmodel plant species, Thlaspi caerulescens, a zinc (Zn) hyperaccumulator, and Thlaspi arvense, a nonhyperaccumulator, using Affymetrix Arabidopsis thaliana ATH1-121501 GeneChip (R) arrays (Affymetrix, Santa Clara, CA, USA). Transcript abundance was quantified in the shoots of agar- and compost-grown plants of both species. Analyses were optimized using a genomic DNA (gDNA)-based probe-selection strategy based on the hybridization efficiency of Thlaspi gDNA with corresponding A. thaliana probes. In silico alignments of GeneChip (R) probes with Thlaspi gene sequences, and quantitative real-time PCR, confirmed the validity of this approach. Approximately 5000 genes were differentially expressed in the shoots of T. caerulescens compared with T. arvense, including genes involved in Zn transport and compartmentalization. Future functional analyses of genes identified as differentially expressed in the shoots of these closely related species will improve our understanding of the molecular mechanisms of Zn hyperaccumulation.

A comparison of thiolated and disulfide‐crosslinked polyethylenimine for nonviral gene delivery

Branched polyethylenimine (25 kDa) is thiolated and compared with redox-sensitive crosslinked derivatives. Both polymers thiol contents are assessed; the thiolated polymers have 390–2300 mmol SH groups/mol, whereas the crosslinked polymers have lower thiol contents. Cytotoxicity assays show that both modified polymers give lower hemolysis than unmodified PEI. Increased thiol content increases gene transfer efficiency but also elevates cytotoxicity. Crosslinking improves plasmid DNA condensation and enhances transfection efficiency, but extensive crosslinking overstabilizes the polyplexes and decreases transfection, emphasizing the need to balance polyplex stabilization and unpacking. Thus, at low levels of crosslinking, 25 kDa PEI can be an efficient redox-sensitive carrier system.

Comparison of in vivo and in vitro digestion on polyphenol composition in lingonberries: potential impact on colonic health

The composition of polyphenols in ileal fluid samples obtained from an ileostomy subject after lingonberry intake was compared with lingonberry extracts obtained after simulated in vitro digestion (IVDL) and subsequent faecal fermentation (IVFL). HPLC-PDA-MS/MS analysis confirmed similar patterns of lingonberry (poly)phenolic metabolism after the in vivo and in vitro digestion, with reduced recovery of anthocyanins and a similar pattern of recovery for proanthocyanidins observed for both methods of digestion. On the other hand, the IVFL sample contained none of the original (poly)phenolic components but was enriched in simple aromatic components. Digested and fermented extracts exhibited significant (P < 0.05) anti-genotoxic (Comet assay), anti-mutagenic (Mutation Frequency assay), and anti-invasive (Matrigel Invasion assay) effects in human cell culture models of colorectal cancer at physiologically-relevant doses (0-50 μg/mL gallic acid equivalents). The ileal fluid induced significant anti-genotoxic activity (P < 0.05), but at a higher concentration (200 μg/mL gallic acid equivalents) than the IVDL. Despite extensive structural modification following digestion and fermentation, lingonberry extracts retained their bioactivity in vitro. This reinforces the need for studies to consider the impact of digestion when investigating bioactivity of dietary phytochemicals.