scholarly journals Cellulases of basidiomycetes for the development of cellulose bioconversion technologies

2020 ◽  
Vol 77 (5) ◽  
pp. 378-385
Author(s):  
S.M. Boiko ◽  
Keyword(s):  
Molecular Weight ◽  
Processing Time ◽  
Genetic Factors ◽  
Carbon Sources ◽  
Culture Fluid ◽  
High Viscosity ◽  
Nutrient Media ◽  
Production Of Culture ◽  
Cellulose Bioconversion ◽  
High Level

Basidiomycetes cultures were screened for the ability to actively express the cellulases complex. Nutrient media with various forms of sugars were used. From 22 cultures of macromycetes (14 species), a group of six cultures with high level activities of extracellular (Il-11 I. lacteus – 70 IU, Fvv F. velutipes – 78 IU, Pe-1 P. eryngii – 87 IU, Ps-1 L. sulphureus – 83 IU, Mg M. giganteus – 74 IU) and intracellular (Sc-51 S. commune – 102 IU) cellulase complex was selected. Cultures of the species exhibit notable differences in the expression of enzymes, which indicates a significant influence of genetic factors on the process of producer selection. Endo-1,4-β-D-glucanases isozymes for most fungi had a molecular weight of 55 kDa and above, except for S. commune, which had more variability of conformation and weight 12–55 kDa. The culture of Il-11 I. lacteus on media with Avicel and filter paper had the highest activity, its endo- and exo-1,4-β-D-glucanases activities ranged 37–39 IU/mL and 18–20 IU/ mL, respectively. The culture of S. commune Sc-51 is able to accumulate a significant amount of intracellular cellulases, but the production of culture fluid with high viscosity complicates technological manipulations and increases processing time. The obtained data allowed us to isolate an Il-11 I. lacteus culture with stable expression and high activity of the cellulases complex at different carbon sources.

scholarly journals Thin shell aerogel fabrication for FIREX-I targets using high viscosity (phloroglucinol carboxylic acid)/formaldehyde solution

2008 ◽  
Vol 26 (3) ◽  
pp. 449-453 ◽  
Author(s):  
H. Yang ◽  
K. Nagai ◽  
M. Nakai ◽  
T. Norimatsu
Keyword(s):  
Carboxylic Acid ◽  
Thin Shell ◽  
Shell Thickness ◽  
High Viscosity ◽  
Formaldehyde Solution ◽  
Resorcinol Formaldehyde ◽  
Foam Structure ◽  
Final Density ◽  
Emulsion Process ◽  
High Level

AbstractCapsules with a thin aerogel shell were prepared by the OO/W/OIemulsion process. (Phloroglucinol carboxylic acid)/formaldehyde (PF) was used as the water phase (W) solution to form the shell of the capsule. PF is a linear polymer prepared from phloroglucinol carboxylic acid. The viscosity of the PF solution can reach a high level of 9×10−5m2/s without gelation while resorcinol/formaldehyde (RF) gelates at ~3–4×10−5m2/s. Using the viscous PF solution, capsule with a 17 µm gel shell was fabricated. This thickness satisfies the specification of the first phase of Fast Ignition Realization Experiment (FIREX-I) at Osaka University. When PF gel was extracted to remove the organic solvent, shrinkage of 9% occurred. The final density of the PF aerogel was 145 mg/cm3. Both the shell thickness and density can satisfy the specification of FIREX-I. The pore size of the PF aerogel was less than 100 nm while that of RF was 200–500 nm. The SEM showed that PF had particle-like foam structure while RF had fibrous-like foam structure.

scholarly journals Screening of local wild-type Xanthomonas spp. for xanthan biosynthesis using media with different carbon sources

2021 ◽  
Vol 26 (4) ◽  
pp. 2800-2807
Author(s):  
IDA ZAHOVIĆ ◽  
JELENA DODIĆ ◽  
SINIŠA MARKOV ◽  
JOVANA GRAHOVAC ◽  
MILA GRAHOVAC ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Carbon Source ◽  
Carbon Sources ◽  
Wild Type ◽  
Biotechnological Production ◽  
Aerobic Conditions ◽  
Pepper Leaves ◽  
Synthetic Media ◽  
Selection Of

In this study the screening of different Xanthomonas strains, isolated from infected crucifers and pepper leaves, for xanthan biosynthesis on semi-synthetic media containing different carbon sources was performed. The success of xanthan biosynthesis was estimated based on xanthan concentration in media and its molecular weight. Glucose and glycerol were investigated as carbon sources in a quantity of 20.0 g/L. Xanthan biosynthesis by different Xanthomonas isolates on two different cultivation media was carried out in Erlenmeyer flasks under aerobic conditions for 168 h. According to the obtained results selection of the carbon source, producing strain and their combination have a statistically significant effect on xanthan quantity and quality. The results obtained in this study indicate that local wild-type Xanthomonas strains isolated from pepper leaves have a great potential for application in biotechnological production of good-quality xanthan on glycerol-based media.

Overview of Performance and Analytical Modeling Techniques for Electromagnetic Heating and Applications to Steam-Assisted-Gravity-Drainage Process Startup

SPE Journal ◽  
2016 ◽  
Vol 21 (02) ◽  
pp. 311-333 ◽  
Author(s):  
Sahar Ghannadi ◽  
Mazda Irani ◽  
Rick Chalaturnyk
Keyword(s):  
High Viscosity ◽  
Gravity Drainage ◽  
Induction Medium ◽  
Oil Sand ◽  
Steam Assisted Gravity Drainage ◽  
Production Wells ◽  
Reservoir Conditions ◽  
Startup Time ◽  
Industry Practice ◽  
High Level

Summary Steam-assisted gravity drainage is the method of choice to extract bitumen from Athabasca oil-sand reservoirs in Western Canada. Under reservoir conditions, bitumen is immobile because of high viscosity, and its typically high level of saturation limits the injectivity of steam. In current industry practice, steam is circulated within injection and production wells. Operators keep the steam circulating until mobile bitumen breaks through the producer and communication is established between the injector and the producer. The “startup” phase is a time-consuming process taking three or more months with no oil production. A variety of processes could be used to minimize the length of the startup phase, such as electromagnetic (EM) heating in either the induction (medium frequency) or radio-frequency ranges. Knowledge of the size of the hot zone formed by steam circulation and of the benefits of simultaneous EM-heating techniques increases understanding of the startup process and helps to minimize startup duration. The aim of the present work is to introduce an analytical model to predict startup duration for steam circulation with and without EM heating. Results reveal that resistive (electrothermal) heating with/without brine injection cannot be a preferable method for mobilizing the bitumen in startup phase. Induction slightly decreases startup time at frequencies smaller than 10 kHz, and at 100 kHz it can reduce startup time to less than two months.

Hardness, wear behavior and processing time of diluent and non-diluent nanocomposite laminates manufactured by vacuum infusion technique

2020 ◽  
pp. 152808372097016
Author(s):  
Sherif M Youssef ◽  
MA Agwa ◽  
Soliman S Ali-Eldin ◽  
M Megahed
Keyword(s):  
Wear Resistance ◽  
Tio2 Nanoparticles ◽  
Composite Laminates ◽  
Processing Time ◽  
Wear Behavior ◽  
High Viscosity ◽  
Resin Infusion ◽  
Woven Glass Fiber ◽  
The Cost ◽  
Infusion Technique

The manufacturing of nanocomposites using the Vacuum Resin Infusion (VRI) technique can be considered a challenging task. The reason for this challenge is the high viscosity of the nanofilled resin. For large composite laminates, the nanofilled resin may be cured before complete mold filling, and thus can be considered as a waste of money. In this study, different weight fractions of TiO2 nanoparticles (0.25 wt. % and 0.5 wt. %) were added to epoxy resin. Also, different weight fractions of ethanol (0.5 wt. % and 1 wt. %) were added to both unfilled and nanofilled epoxy. The processing time, hardness, and wear behavior of the composite laminates were investigated. It was found that the addition of TiO2 nanoparticles improved the hardness and wear behavior of composite laminates but the processing time was high. Also, results showed that adding a small amount of ethanol (0.5 wt. %) and 0.25 wt. % of TiO2 nanoparticles to epoxy reinforced with chopped/woven glass fiber not only reduced the processing time but also improved the hardness and wear resistance as compared to neat composite laminates. Moreover, adding 0.5 wt. % of ethanol and 0.25 wt. % of TiO2 nanoparticles to woven E-glass/epoxy (WN0.25E0.5) gives hardness and wear resistance close to that obtained with woven E-glass/epoxy filled with 0.5 wt. % of TiO2 nanoparticles (WN0.5). It is economical to manufacture WN0.25E0.5 rather than WN0.5 as the cost and processing time of WN0.25E0.5 is lower than WN0.5.

scholarly journals A New Card-Linked Loyalty Program: Estimated and Anticipated Benefits for Payment Transaction Parties

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1956
Author(s):  
Albert Sitek ◽  
Zbigniew Kotulski
Keyword(s):  
Risk Management ◽  
Processing Time ◽  
Loyalty Programs ◽  
Security Level ◽  
Loyalty Program ◽  
Payment Card ◽  
Contextual Risk ◽  
High Level ◽  
In The Beginning ◽  
The Impact

Electronic card payments are getting more and more popular, mainly because of their simplicity, convenience, processing time and high level of security. The fact that a single payment card is issued for a particular cardholder makes it possible to link a card to various services. In this paper, we investigated a usage of a payment card in the loyalty program that incorporates our Contextual Risk Management System (CRMS) to assure a novel intangible reward: Shorter transaction processing time. In the beginning, we emphasize the importance of soft benefits in modern loyalty programs and recall the risk management algorithms and the reputation system that has been used in the CRMS. Then, using an extensive dataset of 2.5 million payment transaction traces (collected within a year from 68 terminals) we estimate potential benefits for merchants and cardholders and try to predict an effect of this system for the future. We also discuss the impact of this system on the real and user-perceived security level.

Plasma viscosity regulates capillary perfusion during extreme hemodilution in hamster skinfold model

1998 ◽  
Vol 275 (6) ◽  
pp. H2170-H2180 ◽  
Author(s):  
Amy G. Tsai ◽  
Barbara Friesenecker ◽  
Michael McCarthy ◽  
Hiromi Sakai ◽  
Marcos Intaglietta
Keyword(s):  
Molecular Weight ◽  
Shear Stress ◽  
Capillary Density ◽  
High Viscosity ◽  
Plasma Viscosity ◽  
Capillary Perfusion ◽  
Low Viscosity ◽  
Arterial Blood ◽  
Wall Shear ◽  
Stress Dependent

Effect of increasing blood viscosity during extreme hemodilution on capillary perfusion and tissue oxygenation was investigated in the awake hamster skinfold model. Two isovolemic hemodilution steps were performed with 6% Dextran 70 [molecular weight (MW) = 70,000] until systemic hematocrit (Hct) was reduced by 65%. A third step reduced Hct by 75% and was performed with the same solution [low viscosity (LV)] or a high-molecular-weight 6% Dextran 500 solution [MW = 500,000, high viscosity (HV)]. Final plasma viscosities were 1.4 and 2.2 cP (baseline of 1.2 cP). Hct was reduced to 11.2 ± 1.1% from 46.2 ± 1.5% for LV and to 11.9 ± 0.7% from 47.3 ± 2.1% for HV. HV produced a greater mean arterial blood pressure than LV. Functional capillary density (FCD) was substantially higher after HV (85 ± 12%) vs. LV (38 ± 30%) vs. baseline (100%).[Formula: see text] levels measured with Pd-porphyrin phosphorescence microscopy were not statistically changed from baseline until after the third hemodilution step. Wall shear rate (WSR) decreased in arterioles and venules after LV and only in arterioles after HV. Wall shear stress (WSR × plasma viscosity) was substantially higher after HV vs. LV. Increased mean arterial pressure and shear stress-dependent release of endothelium-derived relaxing factor are possible mechanisms that improved arteriolar and venular blood flow and FCD after HV vs. LV exchange protocols.

Genetic susceptibility of CYP1A1 gene and risk of pesticide exposure in prostate cancer

2020 ◽  
Vol 29 (4) ◽  
pp. 429-440
Author(s):  
Amar Abhishek ◽  
Nasreen Ghaji Ansari ◽  
Vishwajeet Singh ◽  
Rahul Janak Sinha ◽  
Prabhakar Mishra ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Stress Level ◽  
Genetic Factors ◽  
Pesticide Exposure ◽  
High Stress ◽  
P Value ◽  
Specific Pcr ◽  
Cyp1a1 Gene ◽  
High Stress Level ◽  
High Level

BACKGROUND: The etiology of prostate cancer (PCa) is multi-factorial including environmental and genetic factors. Present study evaluates the association between level of pesticides, stress level and CYP1A1 gene polymorphism with PCa patients. METHODS: A case control study was conducted with 102 PCa patients and age match symptomatic (n= 107) and asymptomatic benign prostatic hyperplasia (BPH, n= 70) patients. Pesticide level was characterized by Gas Chromatography. The oxidative stress and scavenging mechanisms were determined by biochemical method. Two polymorphisms of CYP1A1 gene, rs4646903 and rs1048943, were analyzed by polymerase chain reaction (PCR) followed by restriction fragment length polymorphism and allele specific PCR method. RESULTS: Higher level of pesticide namely beta-hexachlorocyclohexane (β-HCH), Malathion, Chlorpyrifos and Fenvalerate were found in PCa group (all p value: < 0.05). Kruskal Wallis H test depicted that level of β-HCH and Malathion significantly correlated with higher grade of PCa (all p< 0.05). The PCa Patients with simultaneously low antioxidant activity and high stress level tended to suffer worst clinical outcomes. Dominant model of rs4646903 and rs1048943 suggested that substitution is associated with a higher risk of PCa (OR: 2.2, CI: 1.6–3.8, p: 0.009 and OR: 1.95, CI: 1.1–3.4, p: 0.026; respectively) and this risk was also influenced by smoking and pesticide exposure. CONCLUSION: Environmental and genetic factors are reported to raise risk; person with high level of these pesticides especially in high risk genotype might be more susceptible to PCa.

Comparative study of the beta-lactamase activity found in Achromobacter

1983 ◽  
Vol 29 (7) ◽  
pp. 819-826 ◽  
Author(s):  
Roger Levesque ◽  
Robert Letarte ◽  
Jean-Claude Pechère
Keyword(s):  
Molecular Weight ◽  
Genetic Analysis ◽  
Gram Negative Bacteria ◽  
Beta Lactamase ◽  
Gram Negative ◽  
Chromosomal Origin ◽  
Clinical Interest ◽  
High Level ◽  
Hydrolysis Of

A survey of 21 clinical isolates of Achromobacter species demonstrated a high level of β-lactamase activity in all strains tested. The β-lactamases were characterized by isoelectric focusing, purification by affinity chromatography, determination of molecular weight, immunological identity, and genetic analysis. At least three distinct patterns of β-lactamases were found in 19 strains. The kinetic values Km and Vmax measured by a microacidimetric method showed that all three types of enzymes are cephalosporinases and did not hydrolyse oxacillin, cloxacillin, and methicillin. Two of the three types of cephalosporinases studied, namely MULB 901 (isoelectric point (pI) 7.4) and MULB 905 (pI 9.3) are enzymes mediated by genes of chromosomal origin. The MULB 906 (pI 8.1) enzyme, however, which has been previously shown to be mediated by an 8.2 MDal nonconjugative plasmid, showed hydrolysis of cefoxitime, cefotaxin, and moxalactam by the bioassay. In all cases, β-lactamase synthesis appeared constitutive. This study confirms that β-lactamase activity is commonly found in Achromobacter and that these enzymes are different and of clinical interest when compared with those observed in other Gram-negative bacteria.

Turbulent flow drag reduction and degradation with dilute polymer solutions

1970 ◽  
Vol 43 (4) ◽  
pp. 689-710 ◽  
Author(s):  
R. W. Paterson ◽  
F. H. Abernathy
Keyword(s):  
Molecular Weight ◽  
Turbulent Flow ◽  
Drag Reduction ◽  
Average Molecular Weight ◽  
Experimental Studies ◽  
Polymer Degradation ◽  
High Viscosity ◽  
Turbulent Pipe Flow ◽  
Shear Stresses ◽  
Flow Drag

Experimental studies of drag reduction and polymer degradation in turbulent pipe flow with dilute water solutions of unfractionated polyethylene oxide are described. Drag reduction results indicate that the magnitude of the reduction cannot be correlated on the basis of weight average molecular weight, rather the phenomenon depends strongly on the concentration of the highest molecular weight species present in the molecular weight distribution. Polymer degradation in turbulent flow is found to be severe for high molecular weight polymers causing appreciable changes in drag reduction and molecular weight with the duration of flow. Data indicates that drag reduction exists in the limit of infinite dilution suggesting that the phenomenon is due to the interaction of individual polymer molecules with the surrounding solvent and that the extent of reduction is relatively independent of pipe diameter when a comparison is carried out at equal solvent wall shear stresses. Consideration of the high viscosity obtained with solutions in an irrotational laminar flow field suggests this is due to polymer molecule deformation and that this phenomenon is central to the mechanism of turbulent flow drag reduction.

Evidence of re-entrant behavior in laponite-PEO systems

2005 ◽  
Vol 899 ◽  
Author(s):  
Hossein Baghdadi ◽  
Surita R. Bhatia ◽  
Elizabeth E. C. Jensen ◽  
Nalini Easwar
Keyword(s):  
Molecular Weight ◽  
Viscosity Solution ◽  
High Viscosity ◽  
Polymer Chains ◽  
Low Viscosity ◽  
End Distance ◽  
Depletion Force ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Electrostatic Repulsions

AbstractRheology and dynamic light scattering capture re-entrant behavior of laponite-polymer systems. Neat laponite under basics conditions and concentrations of 2wt% or greater forms a viscoelastic soft glass due to electrostatic repulsions. We show that that addition of low molecular weight poly(ethylene oxide) (PEO) melts the glass due to a depletion force. The depletion force speeds up dynamics in the system resulting in a low viscosity solution. A re-entrant viscoelastic solid is formed with the addition of high molecular weight PEO due to the polymer chains bridging between laponite particles. As expected the transition from a low to high viscosity solution scales with the polymer mean square end-to-end distance and gap between laponite particles.

Sign in / Sign up

Export Citation Format

Share Document