scholarly journals Interactions among temperature, moisture, and oxygen concentrations in controlling decomposition rates

2016 ◽  
Author(s):  
Carlos A. Sierra ◽  
Saadatullah Malghani ◽  
Henry W. Loescher
Keyword(s):  
High Temperatures ◽  
Extracellular Enzymes ◽  
High Water ◽  
High Water Content ◽  
Soil Core ◽  
Decomposition Rates ◽  
Environmental Controls ◽  
Arctic Soils ◽  
Wide Range ◽  
Oxygen Concentrations

Abstract. Determining environmental controls on soil organic matter decomposition is of importance for developing models that predict the effects of environmental change on global soil carbon stocks. There is uncertainty about the environmental controls on decomposition rates at temperature and moisture extremes, particularly at high water content levels and high temperatures. It is uncertain whether observed declines of decomposition rates at high temperatures are due to declines in the heat capacity of extracellular enzymes as predicted by thermodynamic theory, or due to simultaneous declines in soil moisture. It is also uncertain whether oxygen limits decomposition rates at high water contents. Here we present results from a full factorial experiment using organic arctic soils incubated at high temperatures (25 and 35 degrees C), a wide range of water-filled pore space WFPS (15, 30, 60, 90 %), and contrasting oxygen concentrations (1 and 20 %). We found support for the hypothesis that decomposition rates increase at high temperatures provided enough moisture and oxygen is available for decomposition. Furthermore, we found that decomposition rate is mostly limited by oxygen concentrations at high moisture levels; even at 90 % WFPS, decomposition proceeded at high rates in the presence of oxygen. Our results suggest an important degree of interactions among temperature, moisture, and oxygen in determining decomposition rates at the soil-core scale.

scholarly journals Interactions among temperature, moisture, and oxygen concentrations in controlling decomposition rates in a boreal forest soil

2017 ◽  
Vol 14 (3) ◽  
pp. 703-710 ◽  
Author(s):  
Carlos A. Sierra ◽  
Saadatullah Malghani ◽  
Henry W. Loescher
Keyword(s):  
Boreal Forest ◽  
High Temperatures ◽  
High Water ◽  
High Water Content ◽  
Organic Soils ◽  
Soil Core ◽  
Decomposition Rates ◽  
Environmental Controls ◽  
Wide Range ◽  
Oxygen Concentrations

Abstract. Determining environmental controls on soil organic matter decomposition is of importance for developing models that predict the effects of environmental change on global soil carbon stocks. There is uncertainty about the environmental controls on decomposition rates at temperature and moisture extremes, particularly at high water content levels and high temperatures. It is uncertain whether observed declines in decomposition rates at high temperatures are due to declines in the heat capacity of extracellular enzymes as predicted by thermodynamic theory, or due to simultaneous declines in soil moisture. It is also uncertain whether oxygen limits decomposition rates at high water contents. Here we present the results of a full factorial experiment using organic soils from a boreal forest incubated at high temperatures (25 and 35 °C), a wide range of water-filled pore space (WFPS; 15, 30, 60, 90 %), and contrasting oxygen concentrations (1 and 20 %). We found support for the hypothesis that decomposition rates are high at high temperatures, provided that enough moisture and oxygen are available for decomposition. Furthermore, we found that decomposition rates are mostly limited by oxygen concentrations at high moisture levels; even at 90 % WFPS, decomposition proceeded at high rates in the presence of oxygen. Our results suggest an important degree of interaction among temperature, moisture, and oxygen in determining decomposition rates at the soil core scale.

scholarly journals Formulation and Study of an Environmentally Friendly Microemulsion-Based Drilling Fluid (O/W) with Pine Oil

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7981
Author(s):  
Roxana P. F. de Sousa ◽  
Glauco S. Braga ◽  
Raphael R. da Silva ◽  
Giovanna L. R. Leal ◽  
Júlio C. O. Freitas ◽  
...  
Keyword(s):  
Drilling Fluid ◽  
Chemical Properties ◽  
Tween 80 ◽  
High Water ◽  
High Water Content ◽  
Fluid Loss ◽  
Pine Oil ◽  
Wide Range ◽  
Solids Content ◽  
Biodegradable Surfactant

This work has developed and evaluated a microemulsion-based drilling fluid formulation with characteristics to be applied in oil wells. The microemulsion was formulated with a solution of water/glycerol, pine oil, and Tween 80, a nonionic and biodegradable surfactant. The physical and chemical properties of the drilling fluid obtained in this work were investigated through rheology and filtration analysis, solids content, aging, lubricity, toxicity, and thermal degradation. A non-toxic microemulsion-based drilling fluid oil-in-water (O/W) with high lubricity (0.07638) and thermal stability was obtained with suitable viscosity, gel strength and low fluid loss (4.0 mL), low solids content (6%), stability in a wide range of salinity conditions, and the possibility of high water content (above 85% in mass fraction). The fluid presented a pseudoplastic behavior, and statistically significant Herschel–Bulkley parameters were obtained.

scholarly journals Designing robust chitosan-based hydrogels for stem cell nesting under oxidative stress

Bioimpacts ◽  
2021 ◽  
Author(s):  
Zahra Olfat Noubari ◽  
Asal Golchin ◽  
Marziyeh Fathi ◽  
Ailar Nakhlband
Keyword(s):  
Oxidative Stress ◽  
Tissue Engineering ◽  
Stem Cells ◽  
Porous Structure ◽  
High Water ◽  
High Water Content ◽  
Dapi Staining ◽  
Antioxidant Genes ◽  
Wide Range ◽  
The Impact

Introduction: Hydrogels are unique candidates for a wide range of biomedical applications including drug delivery and tissue engineering. The present investigation was designed to consider the impact of chitosan-based hydrogels as a scaffold on the proliferation of human bone marrow mesenchymal stem cells (hBM-MSCs) besides neutralization of oxidative stress in hBM-MSCs. Methods: Chitosan (CS) and CS-gelatin hydrogels were fabricated through ionic crosslinking using β-glycerophosphate. The hBM-MSCs were cultured on the prepared matrices and their proliferation was evaluated using DAPI staining and MTT assay. Furthermore, the effect of hydrogels on oxidative stress was assessed by measuring the expression of NQO1, Nrf2, and HO-1 genes using real-time PCR. Results: The developed hydrogels indicated a porous structure with high water content. The toxicity studies showed that the prepared hydrogels have a high biocompatibility/cytocompatibility. The expression of intracellular antioxidant genes was studied to ensure that stress is not imposed by the scaffold on the nested cells. The results showed that Nrf2 as a super transcription factor of antioxidant genes and its downstream antioxidant gene, NQO1 were downregulated. Unexpectedly, the upregulation of HO-1 was detected in the current study. Conclusion: The prepared CS-based hydrogels with desired properties including porous structure, high swelling ability, and cytocompatibility did not show oxidative stress for the nesting of stem cells. Therefore, they could be attractive scaffolds to support stem cells for successful tissue engineering purposes.

scholarly journals Optimalization of multiresidue method for the determination of pesticide residues in fruits

2021 ◽  
Vol 61 (3) ◽  
pp. 221-238
Keyword(s):  
Water Content ◽  
Pesticide Residues ◽  
High Water ◽  
High Water Content ◽  
Detector Response ◽  
Wide Range ◽  
Comprehensive Determination ◽  
Selective Detectors ◽  
Active Substances

The main aim of this study was to optimize the QuEChERS methodology for the comprehensive determination of pesticide residues using a simple and inexpensive gas chromatography equipped with selective detectors working simultaneously (GC-ECD/NPD). The method was validated in accordance with the SANTE/11945/2015 guidelines. Representative fruit matrices were chosen from the commodities group with high water content (apples), and with high acidity and high water content (strawberry) for a 160 compounds in the range of 0.005−0.02 mg/kg. The accuracy of the method was as required (recovery: 70–120%, precision: below 20%) for 135 active substances in apples samples and 137 in strawberries samples. The main advantages of the methodology include: good detector response linearity (R2 above 0.995), low limits of detection (0.005 mg/kg for more than 20 compounds, 0.01 mg/kg for about 120 compounds), possibility of simultaneous determination of a wide range of compounds (including some “difficult” ones) without use of a single residue methods. The simultaneous use of two selective detectors allows to obtain more data during a single dose of the sample and confirmation of the result for most compounds, which allows to prevent false positives ones.

Fluorescence sensors for detection of water based on tetraphenylethene–anthracene possessing both solvatofluorochromic properties and aggregation-induced emission (AIE) characteristics

2021 ◽  
Vol 45 (9) ◽  
pp. 4164-4173
Author(s):  
Yuta Mise ◽  
Keiichi Imato ◽  
Takashi Ogi ◽  
Nao Tsunoji ◽  
Yousuke Ooyama
Keyword(s):  
Water Content ◽  
High Water ◽  
Fluorescence Sensor ◽  
High Water Content ◽  
Fluorescence Sensors ◽  
Aggregation Induced Emission ◽  
Emission Enhancement ◽  
Wide Range ◽  
Water Based

TPE-(An-CHO)4 has been developed as an SFC (solvatofluorochromism)/AIEE (aggregation-induced emission enhancement)-based fluorescence sensor for detection of water over a wide range from low to high water content regions in solvents.

scholarly journals Oxidation Lipid on Fish Cake Catfish (Pangasius sp.) Dissolved in The Extract of Bay Leaf (Eugenia polyantha)

2020 ◽  
Vol 8 (3) ◽  
pp. 91
Author(s):  
Mahiastuti Tribuana Tungga Dewi ◽  
Boedi Setya Rahardja ◽  
Agustono Agustono
Keyword(s):  
Water Content ◽  
Natural Antioxidants ◽  
High Water ◽  
Experimental Methods ◽  
Quality Score ◽  
High Water Content ◽  
Antioxidant Compounds ◽  
White Meat ◽  
Wide Range ◽  
Significant Difference

Catfish (Pangasius sp.) As a source of animal protein. Fish catfish have a thick white meat so that it can be processed into a wide range of diversified products. The process of fried fish cake can result in fat or autooxidation process. Autooxidation can be inhibited by the presence of antioxidant compounds. One source of natural antioxidants are bay leaf Eugenia polyantha.This research was carried out by experimental methods and the use of experimental design of randomized Complete Design (RAL). RAL is used when the material and condition of the experiment are homogeneous. This research consists of four concentrations of extract treatment bay leaf, namely 0%, 10%, 20%, 30%. Fish cake has been fried done soaking for 30 minutes. Water content showed no significant difference (p> 0.05) at 24 hours to 28, this indicated that the addition of bay leaf extract did not affect the moisture content during storage. The high water content at 0 hour is caused by the process of soaking the fish cake  in the extract solution. The highest value is shown by the concentration of 30% at the hour to 0 that is 52.78%, this indicates that the fish cake by soaking can meet the quality score SNI 7757:2013 which is a maximum of 60%. The fat content in the fish cake continues to decrease, indicating the occurrence of oxidation during storage. Levels of TBA in fish cake continue to increase that can be slowed by the extract of bay leaves with a concentration of 30%.

Evaluation of an Immunoisolation Membrane Formed by Incorporating a Polyvinyl Alcohol Hydrogel within a Microporous Filter Support

1997 ◽  
Vol 6 (6) ◽  
pp. 585-595 ◽  
Author(s):  
Andrew R. Baker ◽  
Ronald L. Fournier ◽  
Jeffrey G. Sarver ◽  
Jennifer L. Long ◽  
Peter J. Goldblatt ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Water Content ◽  
Structural Integrity ◽  
High Water ◽  
Membrane Properties ◽  
High Water Content ◽  
Hybrid Hydrogel ◽  
Wide Range ◽  
Pva Hydrogel

An immunoisolation membrane formed by incorporating a high water content polyvinyl alcohol (PVA) hydrogel into a microporous polyether sulfone (PES) filter has been investigated in this study. The PVA hydrogel is formed in situ within the filter pores via glutaraldehyde (GA) crosslinking under acidic conditions. The tortuous nature of the microporous filter pores securely anchors the embedded hydrogel to provide excellent structural integrity. The high void fraction of the PES filter support (>80%) and high water content of the PVA hydrogel (>85% water by weight) allow excellent solute transport rates, while an appropriate level of glutaraldehyde crosslinking supplies the required molecular size selectivity. In vitro permeability measurements made with solutes covering a wide range of molecular sizes demonstrate high transport rates for small nutrient molecules with rapidly diminishing permeabilities above a molecular weight of approximately 1,000 Dalton. Implantation experiments show that the membrane properties are not deleteriously affected by prolonged in vivo exposure or common sterilization techniques. Thus, this hybrid hydrogel/filter membrane system offers a promising approach to the immunoisolation of implanted cells.

scholarly journals Influence of Leaf Physical Properties on Single-Leaf Vibrational Response to Sound

Forests ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 115
Author(s):  
Mengmeng Li ◽  
Jian Kang
Keyword(s):  
Physical Properties ◽  
Noise Reduction ◽  
Plant Species ◽  
Leaf Size ◽  
High Water ◽  
High Water Content ◽  
Vibrational Amplitude ◽  
Sound Stimulation ◽  
Single Leaf ◽  
Wide Range

Plant leaves respond to environmental sounds by vibration. This study aimed to examine such responses by evaluating the influences of physical properties on vibrational amplitude, velocity and frequency before and during sound stimulation. Nine plant species with a wide range of leaf sizes, qualities and thicknesses and petiole lengths, widths and thicknesses were selected. In the absence of external sound, the leaf amplitude was ~1 μm, the vibrational velocity was ~0.05 mm s-1 and the vibrational frequency was ~0–15 Hz. After sound stimulation, however, the amplitude increased by 1–5.4×, the velocity was 1.75–14.1× higher and produced another spectral peak at ~80–95 Hz. Nevertheless, the amplitude and velocity varied by up to 1–10× among species mainly because of differences in leaf texture. However, these factors did not markedly change in succulent leaves because their thick epidermal cuticles and high water content buffered vibrations. In contrast, leathery leaves and papery and membranous leaves were highly responsive to sound stimuli. Leaf size, mass and thickness and petiole length, width and thickness also influenced leaf vibration. There is a positive correlation between noise reduction and leaf velocity. Noise reduction effect increases with the increase in leaf velocity until about 0.6 mm s−1 and then decreases. The relationship between leaf physical properties and leaf vibration may be used to study sound response and noise reduction in different plant species.

Evaporative water loss and the role of cocoon formation in Australian frogs

1998 ◽  
Vol 46 (5) ◽  
pp. 405 ◽  
Author(s):  
Philip C. Withers
Keyword(s):  
Water Content ◽  
Water Loss ◽  
High Water ◽  
Linear Increase ◽  
Evaporative Water Loss ◽  
High Water Content ◽  
Evaporative Water ◽  
Wide Range ◽  
Very High

Measurements of evaporative water loss (EWL; mg min-1) and resistance (R; sec cm-1) for various Australian frogs indicate three general allometric patterns: non-cocooned and non-‘waterproof’ frogs with EWL ∝ Mass0.30 and R independent of body mass at about 1–3 sec cm-1, cocooned frogs with EWL reduced about 50–200-fold and R about 50–200 sec cm-1, and ‘waterproof’ frogs with EWL reduced about 5–100- fold and R about 5–100 sec cm-1. Cocooned frogs have an exponential reduction in EWL and fairly linear increase in R over time, corresponding to the temporal addition of layers to the cocoon. The biophysical properties of cocoon are generally similar for various species, although there is some variation in both resistance per thickness (5–20 × 104 s cm-2) and diffusion coefficient (0.4–2.4 × 10 –5 cm2 s-1). The hygroscopic property of frog cocoon resembles that of mammalian stratum corneum, hair and wool, and mucopolysaccharides; there is a slight increase in water content of cocoon over a wide range of humidities but a very steep increase in water content and substantial hydration and swelling at >96% RH. This extreme hygroscopic behaviour of frog cocoon at very high RH may reflect less polymer cross-linking in frog cocoon and its high digestibility. The prevention of over-hydration of frog cocoon in vivo may be attributed to the restriction of high water content to only very high RH (>96%).

Aspergillus sydowii Strain SCAU066 and Aspergillus versicolor Isolate BAB-6580: Potential Source of Xylanolytic, Cellulolytic and Amylolytic Enzymes

2020 ◽  
Vol 14 (2) ◽  
pp. 15
Author(s):  
Zaidah Zainal ariffin
Keyword(s):  
Extracellular Enzymes ◽  
Biologically Active ◽  
Aspergillus Versicolor ◽  
Aspergillus Sydowii ◽  
Aspergillus Tamarii ◽  
Alternative Source ◽  
Amylolytic Enzymes ◽  
Potato Dextrose Broth ◽  
Wide Range ◽  
Pharmaceutical Industries

Fungi is known to produce a wide range of biologically active metabolites and enzymes. Enzymes produced by fungi are utilized in food and pharmaceutical industries because of their rich enzymatic profile. Filamentous fungi are particularly interesting due to their high production of extracellular enzymes which has a large industrial potential. The aim of this study is to isolate potential soil fungi species that are able to produce functional enzymes for industries. Five Aspergillus species were successfully isolated from antibiotic overexposed soil (GPS coordinate of N3.093219 E101.40269) by standard microbiological method. The isolated fungi were identified via morphological observations and molecular tools; polymerase chain reactions, ITS 1 (5’- TCC GTA GGT GAA CCT GCG G3’) forward primer and ITS 4 (5’-TCC TCC GCT TAT TGA TAT GC-3’) reverse primer. The isolated fungi were identified as Aspergillus sydowii strain SCAU066, Aspergillus tamarii isolate TN-7, Aspergillus candidus strain KUFA 0062, Aspergillus versicolor isolate BAB-6580, and Aspergillus protuberus strain KAS 6024. Supernatant obtained via submerged fermentation of the isolated fungi in potato dextrose broth (PDB) and extracted via centrifugation was loaded onto specific media to screen for the production of xylanolytic, cellulolytic and amylolytic enzymes. The present findings indicate that Aspergillus sydowii strain SCAU066 and Aspergillus versicolor isolate BAB-6580 have great potential as an alternative source of xylanolytic, cellulolytic and amylolytic enzymes.

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