Decomposition Of Macromolecules Research Articles

Kinematic analysis of kinases and their oncogenic mutations - Kinases and their mutation kinematic analysis.

Protein kinases are crucial cellular enzymes that facilitate the transfer of phosphates from adenosine triphosphate (ATP) to their substrates, thereby regulating numerous cellular activities. Dysfunctional kinase activity often leads to oncogenic conditions. Chosen by using structural similarity to 5UG9, we selected 79 crystal structures from the PDB and based on the position of the phenylalanine side chain in the DFG motif, we classified these 79 crystal structures into 5 group clusters. Our approach applies our kinematic flexibility analysis (KFA) to explore the flexibility of kinases in various activity states and examine the impact of the activation loop on kinase structure. KFA enables the rapid decomposition of macromolecules into different flexibility regions, allowing comprehensive analysis of conformational structures. The results reveal that the activation loop of kinases acts as a "lock" that stabilizes the active conformation of kinases by rigidifying the adjacent α-helices. Furthermore, we investigate specific kinase mutations, such as the L858R mutation commonly associated with non-small cell lung cancer, which induces increased flexibility in active-state kinases. In addition, through analyzing the hydrogen bond pattern, we examine the substructure of kinases in different states. Notably, active-state kinases exhibit a higher occurrence of α-helices compared to inactive-state kinases. This study contributes to the understanding of biomolecular conformation at a level relevant to drug development.

Pyrolysis of four waste biomasses and elucidation of reaction kinetics and pyrolytic products

With the increase of bioenergy crops and the rapid development of agriculture, the total amount of solid waste is increasing rapidly. This study quantified the pyrolytic performance and gaseous products of spent coffee grounds (SCG), Chinese medicine residue (CMR), vinasse (VI) and camellia oil shell (COS) by using (derivative) thermogravimetric ((D)TG), Fourier transform infrared spectrometry (FTIR) and mass spectrometry (MS) analyses. There are two main stages of mass loss: volatilisation of volatiles and continuous decomposition of macromolecules. At a heating rate of 20°C/min, COS has the slowest pyrolysis rate compared to the other three. Model-free methods: Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) were used to calculate the activation energy (E) of samples with different conversion rates (α). SCG and VI have the highest average activation energy (about 240kJ/mol), followed by CMR (200kJ/mol), and COS the lowest (175kJ/mol). FTIR was mainly used to detect functional group types (including hydroxyl, carbonyl, aldehyde and ester groups, etc.), while MS co-detected the characteristics of condensable/non-condensable gases (including H2O, CO2, NOx, SOx, C6H6, C7H8, C9H8 and other major gas emissions, pollutants and hydrocarbons). Nitrogen oxides are produced in the range of 500–800°C. SCG and VI emit more gas pollutants than CMR and COS.

Insight into the Effects of Inorganic Element Catalysis and Basic Fuel Properties on the Self-Sustained Smoldering Process of Sewage Sludge

The objective of this study is to investigate the effects of inorganic element catalysis and basic fuel properties of sewage sludge on pyrolysis kinetics and self-sustained smoldering characteristics. The sludge pyrolysis process was explored by thermogravimetric and iso-conversion methods, and it was found that the pyrolysis process can be divided into two stages, which are mainly determined by the organic and inorganic components of the fuel. The inorganic components (e.g., Na, Fe and Mn) have a significant catalytic effect on the release of volatiles and the decomposition of macromolecules. The smoldering experiment revealed that the smoldering front and the evaporation front propagated at stable but different speeds. Among the five fuels, SS4 has the highest smoldering temperature (1070 °C) and the lowest propagation velocity (0.7 cm/min of smoldering velocity and 0.3 cm/min of evaporation velocity), while the carbon density mainly determines the heat release in the oxidation process, and the inorganic elements play a significant catalytic role at different temperatures. The obtained thermodynamic and smoldering characteristics facilitate the development and optimization of the disposal of sewage sludge, emphasizing the importance of considering feedstock composition.

Infrared laser ablation of poly(vinylidene fluoride): The Loss of HF

The mechanism and kinetics of infrared laser ablation of poly(vinylidene fluoride) (PVDF) in vacuum have been investigated to understand how this can be used as a polymer processing technology. The laser heats the surface and initiates decomposition of macromolecules in the molten polymer layer which rapidly leads to production of an ablative flow of polymer decomposition products. There is only a short induction period of up to 2 s before ablation begins. After the initial period, the rate of mass loss increases linearly with the time of laser exposure. Spherical particles with an average diameter of about 100 nm are formed on the surface of the powder coating obtained by laser ablation. The particle distribution ranges from 50 nm to 300 nm. The main gaseous product of ablation is HF from dehydrofluorination. A seccond important ablation process is the formation of gaseous carbenes generated during secondary reactions. Proposed ablation reactions due to laser-induced thermal dehydrofluorination occur in two stages. In the first stage, a double bond appears in PVDF due to direct loss of HF. Subsequent detachment of HF leads to the appearance of both triple bonds and cumulene bonds.

Dynamic relationship between dissolved organic matter and soluble microbial products during wastewater treatment

Dynamics of the dissolved organic matter (DOM) and soluble microbial products (SMP) significantly affected the sustainability of wastewater treatment plants and effluent qualities. In this study, the origin, transformation, and seasonal variation of DOM components in the anaerobic/anoxic/oxic (A2O) units were illustrated with fluorescence analysis. Results show that the anaerobic process transformed humic acid-like substances (HA) and SMP into fulvic acid-like substances (FA) and aromatic proteins (AP), which indicated the decomposition of macromolecules. In cold seasons, the anoxic process turned AP to HA, SMP, and FA; but the oxic process reversed the transformation. In warm seasons, 6.0% of AP decreased while 3.1% of HA, 1.8% of SMP, and 1.0% of FA increased during the oxic process. Proteobacteria strains were isolated from the activated sludge to stimulate the SMP generation, it was found higher temperature facilitated the transformation of FA and HA (humics) to SMP and AP (proteins), which resulted more proteins presented in the wastewater DOM. These findings indicated that the treatment efficiency and DOM quality in A2O processes were influenced by influent quality and/or temperature conditions, and highlighted the generation of SMP by sludge microorganisms, based on which the corresponding strategies considering the seasonal DOM/SMP dynamics were recommended for the stringent regulation of effluents and the sustainability of the receiving water bodies. Besides, the overall fluorescence intensity was positively correlated with the quantified biopolymer contents in SMP, implying the potential of using the fluorescence-derived information to indicate more quantified DOM properties.

Modification of sweet potato (Ipomoea batatas Lam.) residues soluble dietary fiber following twin-screw extrusion

Effect of twin-screw extrusion on soluble dietary fiber (SDF) from sweet potato residues (SPRs) were investigated using optimized conditions, at screw speed of 180 rpm, feed rate at 17 Hz, feed moisture at 40% and extrusion temperature at 150 °C. Extruded SDF, showed higher SDF levels (9.63%–29.25%), cholesterol and sodiumcholate adsorption capacity, radical scavenging capacity, and inhibition of digestive enzymes. Moreover, extrusion effectively reduced particle size and molecularweight of SDF, modulated monosaccharide ratios, and increased water retention capacity (WRC), oil retention capacity (ORC), swelling capacity (SC) and glucose absorption capacity (GAC). Additionally, scanning electron microscopy (SEM) demonstrated decomposition of macromolecules of SDF to smaller fractions and formation of a porous morphology following extrusion. Furthermore, the extruded SDF increased thermal stability as determined by differential scanning calorimetry (DSC). Overall, the SDF from SPRs with improved functional and physiochemical properties could be used as a functional additive in diverse food products.

Pyrolysis of textile dyeing sludge in fluidized bed: Characterization and analysis of pyrolysis products

Fluidized bed pyrolysis (FBP) of textile dyeing sludge (DS) was carried out in a benchtop unit. The FBP char (FC) yield decreased and non-condensable gas yield increased with increasing temperature. The minimum FC yield (73.47 wt%) and maximum non-condensable gas yield (24.10 wt%) were found with addition of kaolin at 850 °C. The maximum condensates yield was observed at 650 °C (i.e. 3.52 wt%) without additives. Catalysts reduced condensate yield and promoted decomposition of macromolecules (e.g. siloxane and dichloroacetic acid allyl ester). DS and FC contained small amounts of heavy metals (e.g. Zn, Ni, Pb, Cr and Cu) and a better sulfur retention ability of CaO at higher temperatures (e.g. 650–850 °C) was observed. The surface morphology of FC was improved significantly with increasing temperature and catalysts addition. CO2, CO and CH4 yields in non-condensable gases increased with temperature and the addition of CaO led to the highest yields of CO (5.46 wt%), H2 (0.35 wt%) and CH4 (1.22 wt%) at 850 °C and the lowest yield of CO2 (0.45 wt%) at 450 °C. Higher temperature promoted release of nitrogen, sulfur and chlorine and catalysts promoted release of nitrogen from DS. Kaolin and Ca-bentonite enhanced release of sulfur, whereas CaO showed good sulfur retention capacity.

Detection of biodegradation degree of sludge using dielectric measurement

Pre-treatments applied before biological sludge utilization technologies aim to modify the sludge structure for enhanced disintegration degree and biodegradability. Among the thermal pre-treatments methods, microwave irradiation is suitable to degrade the polymeric structure of sludge, and to increase the solubility of organic matters. Energetic efficiency of microwave heating is mainly determined by the dielectric properties, such as dielectric constant and dielectric loss factor. Dielectric properties are influenced by the frequency, temperature; composition and consistency of irradiated material, state and bond of water etc. Therefore, physicochemical changes of sludge structure; e.g. hydrolysis of macromolecules, degradation of cell wall of microorganisms, aggregation of particles; contribute to the change of dielectric parameters, as well. In our work we investigated the correlation between the dielectric parameters and structural change and biodegradability indicators. In the case of municipal wastewater, the change of organic matter removal efficiency during wastewater purification technology at a wastewater treatment plant can be detected by the change of dielectric constant. Results related to sludge processing show, that change of organic matter solubility and aerobic biodegradability correlate the change of dielectric loss factor and dielectric constant. With the degradation of polymeric structure of sludge matrix and decomposition of macromolecules caused by thermal effects or chemical pre-treatments led to increased mobility of ions and enhanced polarization of molecules. These effects led to increased dielectric constant and loss factor, what make possible to pre-indicate the efficiency of sludge pre-treatment processes by an in line and real time measurement method.

Bacterias anaerobias: procesos que realizan y contribuyen a la sostenibilidad de la vida en el planeta

Se realiza una revision sobre los aspectos degradativos de materia organica, obtención de energia y nutrientes de las bacterias anaerobias. La importancia de estos microorganismos es el papel que desempenan en los procesos que contribuyen al mantenimiento de la vida misma. Dentro del metabolismo para la descomposicion de macromoleculas, estos microorganismos realizan varios procesos: hidrolisis, acetogenesis y metanogenesis, entre otros, cobija reacciones que se realizan dependiendo de las caracteristicas particulares de la bacteria y de las funciones que cumplen dentro del ciclo degradativo, para la obtencion de nuevos productos dependiendo de las rutas bioquimicas o procesos fermentativos que alli se desarrollan.

How to Construct an Artificial Stomach

Chemical digestion, the decomposition of macromolecules by the action of enzymes, begins in the mouth and stomach but occurs primarily in the small intestine. This exercise shows how to construct a simulated stomach and duodenum using common laboratory equipment and chemicals. The lab clearly demonstrates the effect of a gastric enzyme, pepsin, on proteins while leaving other food substances intact.

Ultrafiltration, chemical and biological oxidation as process combination for the treatment of municipal landfill leachate

A hybrid treatment process was evaluated to reduce the organic load of leachate generated in a former landfill. The leachate, regardless of the time the waste was deposited (“leachate A” has its source in young waste and “leachate B” has its source in old waste), presented high recalcitrance as evidenced by high pH values, salinity (chlorides), COD/BOD5 ratio and concentration of metals. The fractionation of leachate through filtration using micro- and ultrafiltration membranes revealed that leachate B presented a higher proportion of soluble organic compounds, and its aging led to the decomposition of macromolecules. The ultrafiltration of leachate B with a 20 kDa cut-off membrane to a volume concentration factor of 3.2 and transmembrane pressure close to 1.0 bar resulted in flows of 15 to 20 L.m-2.h-1 and removal efficiencies of 76% and 79% for COD and color, respectively. The concentrate, when treated with Fenton reagent at pH 4.0, 0.05 mol H2O2.L-1 and 200 mg Fe2+.L-1, presented its TOC content reduce...

Characterization of Recycled Mushroom Compost Leachate by Chemical Analysis and Thermogravimetry−Mass Spectrometry

Recycled compost leachate (RCL or euphemistically named "goody water") can be a potent source of foul odor on mushroom substrate production sites and contributes to composting smells. A complex mixture of sulfur compounds, fatty acids, and nitrogen containing compounds is responsible for odor production. Fifty samples, collected from 14 compost production sites in Ireland and the U.K. over a 2 year period, were analyzed for chemical properties and by thermogravimetry-mass spectrometry (TG-MS) for compositional differences. Results indicated that aerated samples had lower values of electrical conductivity, redox potential, and dry matter content than nonaerated samples and that the higher thermal stability of aerated samples measured by TGA could be attributed to greater mineralization of the substrate due to aerobic processes. The lower temperatures noted for peak evolution of methane, water, and carbon dioxide from TG-MS analysis suggested that a more energetic process had occurred in aerated RCL storage facilities, producing greater decomposition of macromolecules that volatilized at lower temperatures. Chemical composition, thermal stability of the freeze-dried leachate, pyrolysis profiles, and relative amounts of pyrolysis products were all markers of as to how effective control measures could influence RCL quality.

Kinetics of the enzymatic decomposition of macromolecules with a fractal structure

Mechanisms of enzymatic decomposition of an organic substance consisting of fractal macromolecules of different sizes are studied. A kinetic decomposition equation in which the reaction rate coefficient depends on the characteristic of the fractal structure is formulated. The solution for a fraction of macromolecules of the same size and for a mixture of macromolecules of different sizes is analyzed. It is shown that the decomposition kinetics depends on the fractal structure of the macromolecules and the type of their initial distribution by size. Conditions under which the decrease in the concentration of the organic substance obeys the power law are found. The theoretical relations are used for analyzing the literature data on the decomposition kinetics of organic matter in sea sediments in the time interval from several hours to about one million years. It is shown that in this whole interval the concentration decreases with time according to the universal power law with a 0.14 exponent. The kinetics of enzymatic decomposition of lignin (product of the natural decomposition of plant remains or byproduct of wood processing) is also discussed. It is found that the exponent accounting for the concentration decrease is equal to 0.4 to 0.5 for the decomposition of industrial lignin in bulk water and 1 to 2 for its decomposition in the water with bottom sediments.

Effects of Tween 80 and rhamnolipid on the extracellular enzymes of Penicillium simplicissimum isolated from compost

Extracellular enzymes of microorganisms play an important role in the decomposition of macromolecules in the composting process. In this study, the effects of Tween 80 and rhamnolipid on the extracellular amylase, carboxymethyl cellulose enzyme (CMCase), xylanase and protease of Penicillium simplicissimum isolated from compost were investigated during solid-state fermentation. The results showed that the enzyme activities of amylase, CMCase and xylanase were increased by Tween 80 and rhamnolipid, which, however, had a negative effect on the protease production. The stimulative effects on the three enzymes were quite different during the whole fermentation process. Tween 80 and rhamnolipid also increased the fungal biomass slightly. As a result of the enhanced enzyme activities, the organic matter were also improved to different extents by both surfactants, and the decomposition rates of hemicellulose and cellulose were increased about 8.0% and 11.6% by Tween 80 at best, respectively, as well as 5% and 5.5% by rhamnolipid.

Avoiding Catch-22 of Early Evolution by Stepwise Increase in Copying Fidelity

One of the most famous problems of early evolution is the reconstruction of the evolutionary processes creating a so- phisticated, enzymatically aided replication apparatus from a system of primitive self-replicating oligomers. It is known that the selectively maintained length, and thus the amount of information coded in replicators, are limited by their copying fidelity, and that this length was too short in the primordial phase to code for specific replicase en- zymes. However, as argued generally, copying accuracy could not be increased without the help of specific en- zymes. In this paper, we suggest a step-by-step solution to this paradoxical situation through studying both non- enzymatic or enzymatic replication. In the nonenzymatic case, longer templates may enhance replication fidelity by their structural modification, while longer macromolecules could be a bit more precise replicase enzymes in the enzymatic situation. If this increased copying accuracy is sufficiently high, and naturally if the longer replicators outcompete the shorter ones, then the information content maintained in the winner template is increased. I use simple strategic models to study the possibility of these coevolutionary processes. It is pointed out that the neces- sary per unit increase of copying fidelity decreases rapidly with increased template size, and it could be very small even at shorter templates. Comparing the results to experimental data suggests that most probably it is the speed of replication and decomposition of macromolecules rather than copying accuracy, that limits the length of replicators.

The effect of various ionizing radiation types on polyethylene terephthalate

We examine the effect of 60Co γ-radiation and that of bombardment with α-particles of 23 MeV energy on PETP in order to clarify the influence of a linear energy transfer in the range 0·2−50 KeV/μ on the crosslinking and decomposition of macromolecules, the kinetics of stabilized radical formation, the steric distribution of such radical and their heat resistance. The γ-radiation was found primarily to decompose the PEPT at doses of 1–200 Mrad. The α bombardment at doses from 1 to 10 Mrad also causes decomposition, but this is followed by crosslinking in the range 10–100 Mrad. The continuous saturation method of ESR signals has been used to determine the relaxation parameters (spin-lattice and spin-spin relaxation periods and spin bundle width).

Degradation of polymers in reactive gases

The kinetics and mechanism have been studied for the reaction of ozone with polymers with main chains containing CC bonds, aromatic rings or saturated hydrocarbon links. The reaction proceeds through unstable intermediates such as the bipolar ion −C + − −H OO− or peroxy-radicals, which can isomerize or degrade, causing decomposition of macromolecules. Equations for degradation rates are suggested, taking into account the rates of separate stages of the complex reactions. A method for determining rates and rate constants for reactions of ozone with polymers was found; constants for 12 polymers and important functional groups have been given.