Retention Values Research Articles

Ecological conservation pattern based on ecosystem services in the Qilian Mountains, northwest China

Qilian Mountains is an important ecological security barrier and water conservation area in western China, with an important ecological status. Conducting research on ecosystem services (ESs) in Qilian Mountains can help explore pathways for green development in Qilian Mountains. In this paper, we quantified the ESs of Qilian Mountains and constructed an ecological conservation pattern. The results show that: the ESs of Qilian Mountains were found to be gradually improving from 1980 to 2020. The average values of habitat quality, soil retention, and water conservation of the Qilian Mountains increased by 3.36%, 13.67%, and 41.66%, respectively from 1980 to 2020. Precipitation, NDVI, and NPP contribute significantly to ESs. We have developed an ecological conservation pattern for the Qilian Mountains with Priority Protection Area (PPA), Consolidation and Enhancement Area (CEA), and Coordinated and Optimization Area (COA) as the core, and proposed different management options. Furthermore, the conservation pattern based on double “E + G” (Enclose, Effects, Green development, and Guarantees)will provide new ideas and approaches for ecological management in alpine regions.

Physical Properties of Pulp and Paper: A Comparison of Forming Procedures

Abstract In this work, we used the conventional wet papermaking process and the solution casting procedure to make paper sheets and optimized the relative content of eucalyptus and Simao pine pulps using the mechanical properties of the paper sheet as the evaluation index. The chemical composition, water retention value, zeta potential, carboxyl content, and drainage behavior of the pulp created using the optimal mass ratio for each method were measured, and the resulting paper sheets were characterized via Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and nitrogen adsorption/desorption isotherms. We found that for a ratio of eucalyptus to Simao pine pulps of 94:6 using the wet papermaking process, the mechanical properties of sheets took their optimal values, and the tear, tensile, and burst indexes and the folding endurance were equal to 4.43 mN·m2·g−1, 27.47 N·m·g−1, 1.13 kPa·m2·g−1, and 11.38 times, respectively, whereas the ratio leading to the best possible mechanical performance in the solution casting process was 88:12, and the corresponding paper sheets had tear, tensile, and burst indexes and the folding endurance of 11.73 mN·m2·g−1, 23.03 N·m·g−1, 0.68 kPa·m2·g−1, and 25.50 times, respectively. The cellulose, hemicellulose, and lignin contents of the pulp treated by the solution casting method were lower by 1.88, 3.11, and 2.67 percent, respectively, compared to that obtained via the wet papermaking process. However, the water retention value, zeta potential, and carboxyl content of the pulp obtained via solution casting were higher by 50.31, 123.41, and 50.15, percent, respectively, compared to that obtained via the wet papermaking process. The drainage time obtained via the solution casting method was one-fifth of that obtained via the wet forming process. The paper sheet prepared via the solution casting method was found to exhibit weaker hydrogen bonding, a decreased level of crystallinity (26.64% lower), and an increased compactness and N2 gas adsorption capacity (19.55% and 66.7% higher, respectively) compared to the sheet obtained via the wet papermaking process. This work shows that the physical properties of the paper prepared via the two processes considered here, using their respective optimal weight ratios of the different types of pulp, have their own advantages.

Effect of ball milling on enzymatic sugar production from fractionated corn stover

Corn stover is a valuable feedstock for non-grain sugar production. Each anatomical part has different composition and structural propertied. In this study, corn stover was divided into four parts (stem, leaf, husk, and ear). Their response to ball milling pretreatment and potential for sugar production by enzymatic hydrolysis were studied. Among four parts, the husk obtained the highest monosaccharide concentration due to its lower crystallinity and more suitable chemical composition. Ball milling pretreatment can enhance their structural properties significantly and increase sugar yield. At 20% solid loadings, the monosaccharides concentration in all parts exceeded 80 g·L−1. However, due to the larger particle size, the husk had a poor response to ball milling pretreatment. In contrast, the best response was observed in stem due to the least particle size and lots of cavity structure. Therefore, the enzymatic hydrolysis efficiency of ball milled stem was the highest. Furthermore, the lignin content among various parts before ball milling was the critical factor for the difference in enzymatic hydrolysis efficiency, so as the ash content of the leaves, the crystallinity and water retention value of the stem. After ball milling, higher crystallinity, xylan content, D(10) and water retention value were the key factors leading to low enzymatic hydrolysis conversion of husk. This study provided a guidance for the better corn stover sugar production.

Effect of Lignin-Rich Microfiber on Handsheet Strength

This study explores the effects of using lignin-rich microfibers as a reinforcing material to enhance paper strength. The microfibers prepared by alkaline kneading of organosolv pulp for 1 to 3 hours were characterized in terms of fiber dimensions, residual lignin content, freeness, and water retention value. Longer alkaline kneading times were more effective for improved fiber micronization. In addition, freeness decreased and water retention value increased as a result of the kneading treatment. The microfibers were added at increasing amounts (1%, 3%, and 5% based on oven-dry weight) to commercial bleached kraft pulp to evaluate the effect of microfiber content on handsheet strength. The results showed that microfibers at a level of 5% increased the tensile index of the handsheet by up to 8%, indicating that lignin-rich microfibers have a high potential for use as paper strength additives.

Effect of poly (acrylamide-co-acrylic acid salt) on anti-aging properties and adhesion between acrylonitrile butadiene rubber and polyester fabric

In this study, a multifunction polymeric adhesion promoter and anti-aging compound based on the triethanolamine salt of acrylamide acrylic acid copolymer (COS) was prepared and characterized using Fourier-transform infrared spectroscopy (FTIR). The impact of different COS contents on the tensile, adhesion, and thermal properties of NBR composite and NBR/PET sandwich was evaluated. The NBR composites containing COS displayed good retention of their mechanical properties with increasing thermal ageing time, while the composite without COS showed a decrease in its mechanical properties. The highest tensile strength (17.5 MPa with a retention value of 0.6%) after 7 days of thermal aging was recorded for NBR composite, which contains 5 phr (parts per hundred parts of rubber) of COS (COS 5), compared to NBR composite without COS (COS 0), which recorded 15.1 MPa with a retention value of -27.4%. In addition, the COS 5 composite displayed an improvement in peel strength of 16.4% compared to the COS 0. The results of the thermogarvemetric analysis (TGA) supported the anti-thermal ageing effect of COS, where the initial decomposition temperature (Ti) value increased by 11.7 and 9.3 °C, after addition of 5 and 10 phr of COS to NBR composite, respectively. In addition, the other thermogravemetric parameters investigated displayed a significant increase in their values, which confirms the improvement in thermal stability of NBR composite in the presence of COS. Also, the air permeability of the PET/NBR sandwich decreased by 80% after the addition of 7.5 phr of COS.

Conjugated Microporous Polymers Based on Ferrocene Units as Highly Efficient Electrodes for Energy Storage

This work describes the facile designing of three conjugated microporous polymers incorporated based on the ferrocene (FC) unit with 1,4-bis(4,6-diamino-s-triazin-2-yl)benzene (PDAT), tris(4-aminophenyl)amine (TPA-NH2), and tetrakis(4-aminophenyl)ethane (TPE-NH2) to form PDAT-FC, TPA-FC, and TPE-FC CMPs from Schiff base reaction of 1,1'-diacetylferrocene monomer with these three aryl amines, respectively, for efficient supercapacitor electrodes. PDAT-FC and TPA-FC CMPs samples featured higher surface area values of approximately 502 and 701 m2 g-1, in addition to their possession of both micropores and mesopores. In particular, the TPA-FC CMP electrode achieved more extended discharge time compared with the other two FC CMPs, demonstrating good capacitive performance with a specific capacitance of 129 F g-1 and capacitance retention value of 96% next 5000 cycles. This feature of TPA-FC CMP is attributed to the presence of redox-active triphenylamine and ferrocene units in its backbone, in addition to a high surface area and good porosity that facilitates the redox process and provides rapid kinetics.

Recovery of the Structure, Characteristics, and Application of Thermal Drying-Deteriorated Cellulose Fibers

The large-scale and multilevel application of renewable cellulose resources is one of important strategies for the sustainable development of human society. However, thermal drying is usually an inevitable procedure during utilization of cellulose fibers and it leads to hornification of cellulose fibers, which seriously hinders their further development. A typical feature of hornification is the irreversible shrinkage of cellulose fibers, including shrinkage of the cell lumen, cell wall, and pores on it. These macroscopic structural changes originate from the recrystallization of cellulose molecules caused by forced dehydration during processing. Here, an easy NaOH-urea treatment method to reverse the hornification of hornified cellulose fibers (HCFs) was proposed. The cell lumen, cell wall, and pores of HCFs were restored, and the hydroxyl groups were released inside and on the surface of the fibers; the water retention value (WRV) was relatively increased by 41.8%, and the hornification was reversed by 79%. The drying-induced crystallization and cocrystallization of amorphous cellulose were disrupted, which proved that NaOH-urea treatment can realize a procedural hornification reversal. Finally, the promotion of NaOH-urea treatment on the application of HCFs was verified and explained. This paper will make an important contribution to the reversible characteristic regulation, multiple utilization, efficient recycling, and reuse of cellulose materials.

Effects of Substituting the Two-Spotted Cricket (Gryllus bimaculatus) Meal for Fish Meal on Growth Performances and Digestibility of Striped Snakehead (Channa striata) Juveniles.

This study aimed to investigate the potential of using field two-spotted cricket Gryllus bimaculatus as the main protein source in fish feed for striped snakehead (Channa striata) juveniles. A 10-week feeding effect on growth performance, feed utilization, digestibility of major nutrients, including amino acids, and physiological outputs of nitrogen and phosphorus were determined. A total of 225 C. striata juvenile fish (Initial weight, 15.0 ± 0.1 g) were randomly distributed into three dietary groups in triplicate (25 fish per rectangular aquarium within a semi-recirculating system). Each group was hand-fed one of the experimental diets containing the graded level of a cricket meal (CM) replacing 0%, 50%, and 100% (CM0%, CM50%, and CM100%, respectively) of fish meal (FM) protein component. The results showed that growth performance and protein retention tended to increase with increasing dietary CM levels, whereas the waste outputs of nitrogen (N) and phosphorus (P) decreased. Apparent net protein utilization (ANPU) and P retention values increased with increasing levels of cricket meal inclusion level in the diet. There was a significant reduction in both N and P solid waste and dissolved waste output for snakehead with increased CM inclusion. There were significant effects of CM level on fish whole-body composition in terms of elevated protein and fat content. In conclusion, the CM is a viable alternative protein source for aquaculture feeds and can be included up to 100% as a replacement for FM without compromising the growth performance of striped snakehead Channa striata juveniles. This may also have a more favorable impact, with the potential to reduce N and P loading to the environment.

A high performance all-polymer symmetric faradaic deionization cell

Faradaic deionization (FDI) is an emerging and promising electrochemical technology for stable and efficient water desalination. Battery-type energy storage materials applied in FDI have demonstrated to achieve higher salt removal capacities than carbon-based conventional capacitive deionization (CDI) systems. However, most of the reported FDI systems are based on inorganic intercalation compounds that lack cost, safety and sustainability benefits, thereby curtailing the development of a feasible FDI cell. In this work, we introduce an all-polymer rocking chair practical FDI cell, with a symmetric system composed by a redox-active naphthalene-polyimide (named as PNDIE) buckypaper organic electrodes. First, electrochemical performance of PNDIE in 0.05 M NaCl under open-air conditions is evaluated in both three-electrode half- and symmetric FDI full-cell using typical lab-scale electrode dimensions (1.6 mgPNDIE; 0.78 cm2), revealing promising specific capacity (115 mAh g−1) and excellent cycle stability for full-cell experiments (77 % capacity retention over 1000 cycles). Then, all-polymer rocking chair FDI flow cell was constructed with practical PNDIE electrodes (92.2 mgPNDIE; 9.6 cm2) that delivered large desalination capacity (155.4 mg g−1 at 0.01 A g−1) and high salt-removal rate and productivity (3.42 mg g−1 min−1 at 0.04 A g−1 and 62 L h−1 m−2, respectively). In addition, long-term stability (23 days) experiments revealed salt adsorption capacity (SAC) retention values over 95% after 100 cycles. The overall electrochemical and deionization performances of the reported technology is far superior than the state-of-the-art CDI and FDI techniques, making it a competitive choice for robust and sustainable “water-energy” electrochemical applications.

The effect of different denture cleansing solutions on the retention of polyetheretherketone locator attachments.

Prosthetic cleansing solutions have been reported to cause retention loss in implant locator attachments due to the chemical alterations of these attachments. This study aimed to investigate the effects of different denture cleansing solutions on attachments with different retention values. In this study, 160 polyetheretherketone locator attachments were divided into 4 groups according to their attachment retention values (yellow, pink, clear, and violet). Forty attachments from each group were soaked in four different cleansing solutions (n=10). The attachments from the four groups were immersed in water, sodium hypochlorite, Corega, and Protefix solutions for a period equivalent to 6 months, according to the manufacturer's recommendations. The locator attachments were then subjected to testing using a universal testing machine. Maximum load to dislodgement according to different solutions was evaluated by one-way ANOVA test. Statistical significance was set at p<0.05. The effect of denture cleansing solutions on the retentive values of attachments was statistically significant (p<0.001). Among all cleansing solutions, the highest retention value was found in the violet attachments, and the lowest retention value was found in the yellow attachments. The lowest retention value (0.72±0.05MPa) was observed when the yellow attachments were immersed in Protefix solution, and the highest retention value (1.96±0.15MPa) was observed when the violet attachments were immersed in the Corega solution. For different colored attachments, different cleansing solutions can be suggested to patients.

Effect of Additive and Subtractive Coping Production Techniques on Retention and Marginal Fit of Implant Supported Crowns.

This study investigated the marginal and internal fit and retention of crowns fabricated using 4 different castable pattern production methods, namely plastic burn out coping, computer-aided design and computer-aided manufacturing (CAD-CAM) milled (CAD-CAM-M), CAD-CAM additive (CAD-CAM-A), and conventional. This study consisted of 5 groups including 2 different brands of burn out coping groups (Burn out-Straumann [Burn out-S] group and Burn out-Implance [Burn out-I] group), the CAD-CAM-M group, the CAD-CAM-A group, and the conventional group. A total of 50 metal crown copings were produced in each group with 10 metal crown copings. The marginal gap of the specimens was measured twice-both before and after the cementation and thermocycling processes using a stereomicroscope. A total of 5 specimens were selected randomly-1 from each group for scanning electron microscopy analysis and sectioned longitudinally. The pull-out test was performed on the remaining 45 specimens. The lowest marginal gap value was observed in the Burn out-S group before and after cementation with 88.54-97.48 μm, respectively, while the highest marginal gap was observed in the conventional group (186.27-200.58 μm). Implant systems did not significantly affect the marginal gap values (P > .05). Marginal gap values increased significantly after cementation and thermal cycling in all the groups (P < .0001). The highest retention value was measured in the Burn out-S group while the lowest in the CAD-CAM-A group. The highest occlusal cement gap values were observed in the coping groups (Burn out-S and Burn out-I groups), and the lowest in the conventional group in the scanning electron microscopy analysis. The marginal fit and retention values of the prefabricated plastic burn out coping technique was superior when compared with the other techniques, providing that internal fit was superior with the conventional technique.

Preservatives penetration and retention in post-treated cross-laminated timber panels with different layup and thickness

Cross-laminated timber (CLT), a prefabricated multilayer engineered wood product, is a promising construction material for mid-and-high rise buildings due to its good mechanical properties, renewability, and low-carbon footprint. However, the vulnerability of CLT to biodeterioration limits its broad applications. Preservative treatment is an effective method of increasing the service life of structural wood products, while the treatment of CLT has not been widely studied. Herein, we fabricated 3- and 5-ply CLT panels and treated them with Cu-based preservatives. The effects of panel layup (lengthwise and crosswise) and thickness (3-and 5-layer) on the impregnation quality (i.e., Cu penetration and retention) are investigated using a color-based indicator approach and X-ray fluorescence spectroscopy . Generally, the Cu penetration ratio was mostly above 90%, especially for the top layers (1st layer in 3-ply and 1st and 2nd layers in 5-ply) of the treated CLT panels. Similarly, higher Cu retention values were observed in the 1st layer of the 3- and 5-layer CLT panels. Further, there was a similarity in the Cu penetration of the 2nd layer in 3- and 5-ply CLT, indicating the preservative diffusion across adjacent layers is negligible in the preservative treatment of lumber-based wood composites. Overall, copper-azole type C (CA-C) exhibited better treatability than micronized copper azole (MCA) for CLT panels, resulting in higher Cu penetration and retention across the panels. Also, we found the lengthwise orientation preferable in fabricating preservative-treated CLT, this is due to the complete panel protection of the 1st and 2nd layers at all panel locations. Thus, our results show the feasibility of successfully treating CLT, especially when CA-C preservative and lengthwise orientation are utilized in fabricating the panels.

Evaluation of debonding force of screw-retained lithium disilicate implant-supported crowns cemented to abutments of different designs and surface treatments

Statement of problemStraight preparable abutments provide an alternative to titanium bases (Ti-bases) for single-unit screw-retained implant-supported restorations. However, the debonding force between crowns with a screw access channel cemented to preparable abutments and Ti-bases of different designs and surface treatments is unclear. PurposeThe purpose of this in vitro study was to compare the debonding force of screw-retained lithium disilicate implant-supported crowns cemented to straight preparable abutments and Ti-bases of different designs and surface treatments. Material and methodsForty laboratory implant analogs (Straumann Bone Level) were embedded into epoxy resin blocks that were randomly divided into 4 groups (n=10 each) according to the abutment type used: CEREC group, Variobase group, airborne-particle abraded Variobase group, and airborne-particle abraded straight preparable abutment group. All specimens were restored with lithium disilicate crowns and cemented with resin cement to the corresponding abutments. They were thermocycled (from 5 to 55 °C for 2000 cycles) followed by cyclic loading (120 000 cycles). The tensile forces required to debond the crowns from the corresponding abutments were measured (N) by using a universal testing machine. The Shapiro–Wilk test of normality was used. Comparison between the study groups was done with 1-way ANOVA (α=.05). ResultsTensile debonding force values were significantly different according to the type of abutment used (P<.05). The highest retentive force value was recorded in the straight preparable abutment group (928.1 ±222.2 N) followed by the airborne-particle abraded Variobase group (852.6 ±164.6 N), and the CEREC group (498.8 ±136.6 N); the lowest value was reported in the Variobase group (158.6 ±85.2 N). ConclusionsThe retention of screw-retained lithium disilicate implant-supported crowns cemented to airborne-particle abraded straight preparable abutments is significantly higher than to non-surface treated Ti-bases and similar to airborne-particle abraded ones. Abrading abutments with 50-mm Al2O3 significantly increased the debonding force of the lithium disilicate crowns.

Enhanced impact resistance of three‐dimensional woven composites with double‐layer core structure

AbstractIn this study, to further improve the anti‐impact property of 3D woven spacer composites (3DWSC), three kinds of integrated 3DWSC with double‐layer cores assembled at different height combinations of 4 + 8 mm, 6 + 6 mm, and 8 + 4 mm, were designed and prepared. And the impact performances and the post‐impact lateral compressive properties of the resulting composites were investigated and compared to the single‐layer 3DWSC of the same height. The results show that among the three combinations, 3DWSC‐4 + 8 has the highest contact force value of 2454.33 N at 10 J, which is 90.60% higher than that of single‐layer 3DWSC. And the residual compressive strength of 3DWSC‐4 + 8 maintains 91.30% after 10 J energy impact, while the retention value of single‐layer 3DWSC is only 68.43%. The above results can be attributed to the fact that the addition of the middle panel in double‐layer 3DWSC is benefical to improve the capacity of the material to withstand transverse load or bending moment and to absorb more energy through its damage compared to the single‐layer 3DWSC. In addition, the SEM images showed that only resin cracks in the double‐layer 3DWSC and no fiber breakage and delamination, indicating exceptional mechanical stability of the as‐prepared double‐layer 3DWSC. This work can serve as a reference for the design and fabrication to multi‐layer 3DWSC, a promising material in the field of high‐performance composites.

Evaluation of the effectiveness of transobturator tape operation in the treatment of stress incontinence

Abstract&#x0D; Background/Aims:: In this study, In this study, we aimed to assess the effectiveness of Transobturator Tape Operation in the treatment of Stress İncontinence &#x0D; Methods: We retrospectively evaluated 454 patients who had TOT operations due to stress urinary incontinence between January 1, 2017, and December 31, 2020, at the İstanbul Kanuni Traning and Research Hospital. The basic clinical characteristics of the participants were recorded. The number of daily peds, values of Q-type test and urinary retention, and scores of urogenital disorder inventory-6 and impact of incontinence inquiry form at the clinical evaluation perioperatively and 6 months after the operation. Data analysis of the study was done with the SPSS version 24.0 package program. Kolmogorov-Smirnov test was used for normality analysis. Wilcoxon test was used for the comparisons of preop and postop data. It was considered statistically significant when the P value was below 0.05&#x0D; Results: The study was conducted on 454 patients aged 26-83 years with a mean age of 50.3±10 years. The overall complication rate was 15.9. The rate of those who recovered six months after the operation was 89.6%. The number of daily peds, values of Q-tip test and urinary retention, and scores of questionnaires were significantly reduced after surgery (p=0.001).&#x0D; Conclusions: The TOT operation can be preferred in treating stress incontinence with acceptable success and outcome. The scales of questionnaires successfully determine patient satisfaction with surgical efficacy for SUI.

Computational Approach to Drug Penetration across the Blood-Brain and Blood-Milk Barrier Using Chromatographic Descriptors.

Drug penetration through biological barriers is an important aspect of pharmacokinetics. Although the structure of the blood-brain and blood-milk barriers is different, a connection can be found in the literature between drugs entering the central nervous system (CNS) and breast milk. This study was created to reveal such a relationship with the use of statistical modelling. The basic physicochemical properties of 37 active pharmaceutical compounds (APIs) and their chromatographic retention data (TLC and HPLC) were incorporated into calculations as molecular descriptors (MDs). Chromatography was performed in a thin layer format (TLC), where the plates were impregnated with bovine serum albumin to mimic plasma protein binding. Two columns were used in high performance liquid chromatography (HPLC): one with immobilized human serum albumin (HSA), and the other containing an immobilized artificial membrane (IAM). Statistical methods including multiple linear regression (MLR), cluster analysis (CA) and random forest regression (RF) were performed with satisfactory results: the MLR model explains 83% of the independent variable variability related to CNS bioavailability; while the RF model explains up to 87%. In both cases, the parameter related to breast milk penetration was included in the created models. A significant share of reversed-phase TLC retention values was also noticed in the RF model.

RPLC METHOD DEVELOPMENT AND VALIDATION FOR THE SIMULTANEOUS DETERMINATION OF SELECTIVE SEROTONIN REUPTAKE INHIBITORS IN TABLET FORMULATIONS

Objective: Selective serotonin reuptake inhibitor (SSRIs) compounds are the most used compounds in the treatment of depression. The determination of chromatographic separation and quantitative determination of these compounds is very important in the clinical use of these compounds and the success of biopharmaceutical studies. For this reason, this study, it was aimed to optimize the chromatographic conditions for the quantitative determination of SSRIs in tablet formulation by Reversed phase liquid chromatography method.&#x0D; Material and Method: The optimum separation condition for the studied compounds was determined based on the relationship between the retention values of the compounds and the pH and the content of the mobile phase. Chromatographic determination was made on the X Terra C18 column (250 x 4.6 mm I.D., 5 μm), which is widely used for the determination of hybrid-based and basic compounds. The validation of the developed method was carried out based on the parameters of linearity, precision, and accuracy.&#x0D; Result and Discussion: The developed and validated method was successfully applied for the determination of active ingredients in the tablet dosage form. The experimental results of the amount of studied SSRIs in selected commercial tablets are in good agreement with the label claims. The calculated percent recoveries show that the sample preparation techniques developed for the quantification of the compounds studied are not affected by interferences. The evaluation of the obtained results showed that the developed method is suitable for the routine use of studied compounds.

Electrochemical characterization of nitrocoumarin-modified nanostructured electrode platforms: New precursors for the electrocatalysis of NADH

All synthesized nitrocoumarins, 3-acetyl-6-nitrocoumarin 6-Coum, 3-(3-nitrocinnamoyl)-coumarin 3-CinCoum, 3-(4-nitrocinnamoyl)-coumarin 4-CinCoum, and 3-(4-nitrocinnamoyl)-6-nitrocoumarin 4-Cin-6-Coum, were used to generate novel nanostructured multiwalled carbon nanotube (MWCNT) electrode platforms that were electrochemically activatable to generate the redox pair ArNHOH/ArNO. This redox pair is capable of acting as a mediator in electrocatalysis of NADH oxidation.Nitrocoumarin-modified nanostructured electrode platforms were prepared using both drop casting and buckypaper (BP) methods for comparative purposes, and they showed no differences in their electrochemical responses.It was observed that the compound most easily reduced was 4-Cin-6-Coum. The reduction occurred first at the 4-nitrocinnamoyl group due to the withdrawing electron effect exerted by the cinnamoyl carbonyl group.The heterogeneous transfer rate constant, kh, was calculated for all of the redox mediators, and they decreased in the order 4-CinCoum> 3-CinCoum> 6-Coum> 4-Cin-6-Coum (II). On the other hand, we observed no significant differences for retention of the redox pairs ArNHOH/ArNO from the nitrocoumarin precursor compounds on the electrode, and the retention values ranged from 79.6 to 91.6% after one hour of working with the nanostructured electrodes.With this electrocatalytic response, it is possible to develop an amperometric sensor for the determination of NADH that includes nanostructured platforms with nitrocoumarins. We obtained LODs of 2.95 µM and 3.43 µM for 6-Coum and 4-Cin-6-Coum (II), respectively.

Major Improvement in the Cycling Ability of Pseudocapacitive Vanadium Nitride Films for Micro‐Supercapacitor

AbstractVanadium nitride film made using a thin film deposition technique is a promising electrode material for micro‐supercapacitor applications owing to its high electrical conductivity and high volumetric and surface capacitance values in aqueous electrolyte. Nevertheless, the cycling stability has to be improved to deliver good capacitance during a large number of cycles. Here, it is shown that vanadium nitride films made by a magnetron sputtering deposition method exhibit remarkable cycling stability (high capacitance retention value after 150 000 cycles), ultra‐high rate capability (75% of the initial capacitance at 1.6 V s−1), while providing high surface capacitance values (≈1.4 F cm−2) and very low ageing of the VN electrodes (no loss of performance after 13 months). Additionally, new findings regarding the location of vanadium oxides species responsible for the charge storage mechanism in pseudocapacitive VN films are revealed by transmission electron microscopy electron energy‐loss spectroscopy analyses at the nanoscale.

Biodegradation of oil-contaminated aqueous ecosystem using an immobilized fungi biomass and kinetic study

Remediation of environmental oil pollution with the usage of fungal organisms has proven to be a successful cleanup bioremediation method for organic contaminants. To investigate the breakdown of oil pollutants in water environments, biosurfactant-producing fungi have been isolated from oil-polluted soil samples. 16s rRNA sequencing technique was performed to identify the fungal organism and phylogenetic tree has been constructed. A variety of biosurfactant screening tests have demonstrated the better biosurfactant producing ability of fungi. The emulsion's stability, which is essential for the biodegradation process, was indicated by the emulsification index of 68.48% and emulsification activity of 1.3. In the isolated biosurfactant, important functional groups such as amino groups, lipids, and sugars were found according to thin layer chromatography analysis with a maximum retention value of 0.85. A maximum oil degradation of around 64% was observed with immobilized beads within 12 days. The half-life, and degradation removal rate constant of 20.21 days and 0.03 day−1, respectively, have been determined by the degradation kinetic analysis. GCMS analysis confirmed the highly degraded hydrocarbons such as nonanoic acid and pyrrolidine. The immobilized fungi exhibit better oil biodegradability in aqueous solutions.