Wedge method for landfill stability analysis considering temperature increase

The increase in landfill temperature often results in shear strength reduction of both the solid waste and the liner, which leads to slope instability. However, very few landfill slope analysis methods can simultaneously consider the effect of temperature on the shear strength of the waste solid and the liner. In this study, based on the strength parameters of the liner and waste with temperature, a wedge method for translational failure analysis of landfills considering temperature increase was established. The results showed that rising temperatures caused by biochemical degradation at the bottom and middle of the landfill reduced the anti-slide force of back slope more than that of bottom slope. With the leachate level increasing, the effect of temperature rise on landfill stability became obvious. The feasibility of the proposed wedge method was verified by the engineering case study of Xiaping Landfill, Shenzhen, China. This study probably provides important guidance for the design, operation and management of municipal solid waste landfills.

Isolation and identification of a 2,3,7,8-Tetrachlorodibenzo-P-dioxin degrading strain and its biochemical degradation pathway

This study aims to find a high-efficiency degradation strain which can biodegrade the 2,3,7,8-Tetrachlorodibenzo-P-dioxin (2,3,7,8-TCDD). In this paper, a new fungus strain was isolated from activated sludge of Dagu Drainage River in Tianjin which was able to degrade 2,3,7,8-TCDD in the medium. Based on its morphology and phylogenetic analysis of its 18S rDNA sequence, the strain was identified as Penicillium sp. QI-1. Response surface methodology using central composite rotatable design of cultural conditions was successfully employed for optimization resulting in 87.9 % degradation of 2,3,7,8-TCDD (1 µg/mL) within 6 days. The optimum condition for degrading 2,3,7,8-TCDD was at 31℃ and pH 7.4. The biodegradation process was fitted to a first-order kinetic model. The kinetic equation was Ct=0.939e− 0.133t and its half-life was 5.21d. The fungus strain degraded 2,3,7,8-TCDD to form intermediates, they were 4,5-Dichloro-1,2-benzoquinone, 4,5-Dichlorocatechol, 2-Hydrooxy-1,4-benzoquinone, 1,2,4-Trihydroxybenzene and β-ketoadipic acid. A novel degradation pathway for 2,3,7,8-TCDD was proposed based on analysis of these metabolites. The results suggest that Penicillium sp. QI-1 may be an ideal microorganism for biodegradation of the 2,3,7,8-TCDD-contaminated environments.

On Environmental Biotechnology of Bioremediation

Environmental biotechnology (EB) can play positive and an important role in detoxifying and eliminating pollutants, and cleaning up the contaminated sites of ecosystems, but the development of any EB is based largely on the scientific knowledge and results of (micro)biology and chemistry, and then application mainly on engineering and management. Biodegradation and bioremediation by definition are different in meaning and, as a result, they must be treated differently. On the fundamental basis, the biochemical reactions and the biochemical degradation pathway of any targeted toxicant concerned are basic information before the degradability of the selective pollutant by a microorganism can be claimed. Bioremediation becomes feasible for implementation with the knowledge of the biochemical reactions by the biological agent coupling with the engineering and management to achieve a successful attempt at a site. Though the degradability by a microorganism can be achieved in laboratory condition, the cleaning up of the pollutant at any site needs additional information and knowledge of the physical, chemical and ecological characteristics of the site to allow any success to be achieved. The broad EB can include utilization of pure and selective microorganisms, the biochemical reactions by either pure or mixed culture, enzymes, and metabolic products of microorganisms. In addition, microorganisms may also work in the form of biofilm to carry out the function to detoxify the toxic environmental chemicals. In addition to microorganisms, plants can play an important role in phytoremediation. Overall, environmental biotechnology needs at least three steps to prove its effectiveness from concept testing in laboratory, establishment of the mechanisms involved, workability in complex system and ecosystems, and lastly the implementation and practice on site. A laboratory success on degradation cannot be quickly and simply treated as a claim of EB for bioremediation for application.

Lead Compounds in the Context of Extracellular Vesicle Research

Studies of small extracellular vesicles (sEVs), known as exosomes, have been flourishing in the last decade with several achievements, from advancing biochemical knowledge to use in biomedical applications. Physiological changes of sEVs due to the variety of cargos they carry undoubtedly leave an impression that affects the understanding of the mechanism underlying disease and the development of sEV-based shuttles used for treatments and non-invasive diagnostic tools. Indeed, the remarkable properties of sEVs are based on their nature, which helps shield them from recognition by the immune system, protects their payload from biochemical degradation, and contributes to their ability to translocate and convey information between cells and their inherent ability to target disease sites such as tumors that is valid for sEVs derived from cancer cells. However, their transport, biogenesis, and secretion mechanisms are still not thoroughly clear, and many ongoing investigations seek to determine how these processes occur. On the other hand, lead compounds have been playing critical roles in the drug discovery process and have been recently employed in studies of the biogenesis and secretion of sEVs as external agents, affecting sEV release and serving as drug payloads in sEV drug delivery systems. This article gives readers an overview of the roles of lead compounds in these two research areas of sEVs, the rising star in studies of nanoscale medicine.

Biochemical Degradation of Chitosan over Immobilized Cellulase and Supported Fenton Catalysts

This paper describes the application of Fe-MCM-48 (Mobil Composition of Matter No.48) and cellulase-MCM-48 catalysts for the depolymerization of chitosan. The results show that H2O2 is a good oxidant for the depolymerization of chitosan in the presence of Fe-MCM-48. The average polymerization degree of the product decreased to 6.1, and decreased to 29.2 when cellulase-MCM-48 was used as a catalyst, because the effect of the enzyme was affected by the molecular structure of chitosan. When both materials were used for depolymerization, the average degree of polymerization sharply decreased to 3.8. The results show that the two degradation methods can promote each other to obtain oligosaccharides with a lower degree of polymerization. This provides a new method for the controllable degradation of chitosan and lays a good foundation for the industrial production of chitosan oligosaccharides with a low degree of polymerization.

Accurate conformational stability and cationic structure of piperidine determined by conformer-specific VUV-MATI spectroscopy

Piperidine has received attention in pharmaceutical synthesis and biochemical degradation because of its conformational activity.

Bio-agent de retanare utilizat in procesarea pieilor si procedeu de obtinere

Currently, the leather industry has to deal with very high costs for waste treatment and disposal. As a result, it is recommended to subject the organic protein waste from tanning to biochemical treatments for recycling in the industry. The degree of novelty lies primarily in the fact that the starting point of the promoted technologies is obtaining new complex products by processing organic waste and using it in tanneries. The lime fleshings resulting from the hide fleshing operation represents the highest amount of reusable leather material of approx. 25%. This paper presents an innovative process for the biochemical degradation of hide waste resulting from hide fleshing in order to obtain a retanning/filling agent used in leather processing.