Increase In Excess Research Articles

L-proline-based deep eutectic solvents as green and enantioselective organocatalyst/media for aldol reaction

The use of chiral deep eutectic solvents (DESs) based on the natural amino acid L-proline and various glycols presents an environmentally friendly approach for important CC bond formation reactions. These DESs serve as both organocatalysts and reaction media in the aldol reaction, reducing the need for additional toxic or hazardous chemicals. By employing these DESs, we were able to activate the desired reaction through the condensation of ketones and L-proline via enamine activation. This approach eliminates the requirement for traditional, often environmentally harmful, organic solvents. Notably, diethylene glycol played a crucial role in modulating the reaction performance, including conversion and enantioselectivity. Diethylene glycol is a relatively safer alternative compared to other commonly used solvents or additives with potential environmental and health risks. Moreover, reducing the L-proline content in the DESs led to a slight increase in the enantiomeric excess of the predominant diastereomeric product. This finding suggests the possibility of minimizing the use of L-proline, which can be advantageous from both cost and environmental perspectives.The results of these reactions demonstrate promising green outcomes, with a diastereomeric ratio up to 25:1 for the major anti-isomer, showcasing excellent selectivity (>90 % ee). In addition to these high enantiomeric excess values, quantitative yields in the aldol reaction highlight the potential for high efficiency and reduced waste production.Overall, the utilization of chiral DESs based on L-proline and glycols offers a greener alternative for enantioselective organocatalytic reactions. This approach minimizes the use of hazardous catalysts, reduces waste generation, and demonstrates impressive selectivity, paving the way for more sustainable synthetic methodologies.

Base excess as a predictor of neonatal mortality in neonatal sepsis

Background: Neonatal sepsis is responsible for approximately 15% of all neonatal deaths in the world. Despite of availability in advanced medical healthcare facilities for mother and neonates, incidence of mortality secondary to sepsis especially in developing countries like India is more common. Metabolic acidosis is the most common form of acid base imbalance in neonatal sepsis which can be analyzed with increased levels of base excess. Hence early diagnosis of neonatal sepsis can be done by determining base excess. Methods: This is a prospective observational study conducted in NICU at Cheluvamba Hospital, Mysore. 73 term neonates with suspected sepsis were enrolled in the study who were on regular follow-up and treatment till death/discharged from NICU. Base excess value is obtained from the arterial blood gas analysis from each subject and it was compared with survivor and non-survivor group along with other study parameter Results: Out of 73 subjects, incidence of non survivors group with severe increase in base excess is 75%. To predict the mortality, we compared it with standard base excess which showed the prediction of more than 60%, with significant AOC (0.827) of very near to one in ROC curve, with statistically significant (p<0.001) sensitivity of 92.59%, specificity of 63.04%, positive predictive value of 59.5%, negative predictive value of 93.5%. Conclusions: In present study we have proved that base excess is an important parameter for the early diagnosis and for early intervention in neonatal sepsis.

Effect of Mn content on the structure, electromagnetic properties, and electromagnetic wave absorption characteristics in La0.7Sr0.3Mn1+xO3

The perovskite manganese oxide, La0.7Sr0.3Mn1+xO3 (x = −0.4, −0.2, 0, 0.2, 0.4, 0.6, 0.8, 1.0), was synthesized using the solid-state reaction method. A single-phase perovskite structure was obtained at the stoichiometric composition (x = 0). However, with an increase in Mn excess (x > 0), secondary phases of Mn2O3 and Mn3O4 formed and increased, while La2O3 and Sr-rich phases emerged when Mn is deficient (x < 0). The electrical conductivity, permittivity, and permeability of the samples showed significant variations with x, as both charge transport and magnetism originate from the presence of Mn. Complex permittivity (ε', ε") and permeability (μ', μ") spectra were utilized to calculate RL maps based on a transmission line theory. For samples with x ≥ 0, which exhibited relatively high values of ε' and ε", there was no significant absorption of electromagnetic (EM) waves within the measured frequency range (0.1 ≤ f ≤ 18 GHz) due to high EM wave reflection. Conversely, the Mn-deficient samples (x = −0.2, −0.4) demonstrated excellent EM wave absorption properties in the GHz range. This can be attributed to their favorable impedance matching characteristics, resulting from significantly reduced ε' and ε" values in the Mn-deficient samples. Notably, the sample with x = −0.2 exhibited the most outstanding EM wave absorption characteristics, with an RL value of −56 dB at a frequency of 2.33 GHz and a thickness of 7.59 mm. Additionally, it achieved an RL value of −50 dB at 9.8 GHz and 2.90 mm thickness.

Functionalized Amphiphilic Block Copolymers and Complex Emulsions for Selective Sensing of Dissolved Metals at Liquid-Liquid Interfaces.

Increasing contamination in potable water supplies necessitates the development of sensing methods that provide the speed and selectivity necessary for safety. One promising method relies on recognition and detection at the liquid-liquid interface of dynamic complex emulsions. These all-liquid materials transduce changes in interfacial tensions into optical signals via the coupling of their chemical, physical, and optical properties. Thus, to introduce selectivity, it is necessary to modify the liquid-liquid interface with an interfacially stable and selective recognition unit. To this end, we report the synthesis and characterization of amphiphilic block copolymers modified with metal chelators to selectively measure the concentrations of dissolved metal ions. We find that significant reduction in interfacial tensions arises upon quantitative addition of metal ions with high affinity toward functionalized chelators. Furthermore, measurements from UV-vis spectroscopy reveal that complexation of the block copolymers with metal ions leads to an increase in surface excess and surfactant effectiveness. We also demonstrate selective detection of iron(III) cations (Fe3+) on the μM levels even through interference from other mono-, di-, or trivalent cations in complex matrices of synthetic groundwater. Our results provide a unique platform that couples selective recognition and modulation of interfacial behaviors and demonstrates a step forward in the development of the multiplexed sensing device needed to deconvolute the complicated array of contaminants that comprise real-world environmental samples.

Investigation on combustion efficiency of the hydrogen–oxygen mixture at various pressures and excess oxidizer based on experimental and theoretical studies

One of the ways to improve the efficiency of power plants, including nuclear power plants, can be the use of hydrogen energy complexes and hydrogen-oxygen steam generators in their composition. This is done by electrolysis production of hydrogen and oxygen and their further use in technological schemes of power units in the form of thermal energy. Fundamental in assessing the efficiency of such use of hydrogen technologies is the efficiency of hydrogen combustion in oxygen medium under different schematic-parametric conditions. In this paper combustion processes were studied in terms of evaluating efficiency of the hydrogen-oxygen mixture combustion at various pressures and an oxidizer excess. For this purpose, a calculation model of combustion processes of the hydrogen-oxygen mixture, including heat and mass transfer under the boundary conditions of the experiment was verified on the basis of the experimental data, obtained at 4-section flame tube. Has shown that increasing the pressure of the combustion products leads to a noticeable decrease in hydrogen underburning. The maximum effect is observed in the third section of the flame tube (a reduction by 56.72%), and the minimum effect is found in the first section (a reduction by 7.58%). In this case, the average specific reduction in hydrogen underburning in sections I-IV of the flame tube within the considered pressure ranged between 8.13, 17.41, and 31.34%/MPa, respectively. An increase in an oxidizer excess lead to a regular decrease in hydrogen underburning. In this case, the maximum decrease in hydrogen underburning is achieved with an oxidizer excess ratio of 2 in the third section of the flame tube (a reduction by 58.86%). At the same time, an increase in the positive effect of increasing pressure is observed. In this case, in the first two sections of the flame tube, the greatest dependence on the increase of an oxidizer excess ratio is observed. Thus, the maximum relative reduction in hydrogen underburning is achieved at the pressure of 6 MPa, and as a result amounts to 24.46% and 43.5% with the oxidizer excess ratio at 1.5 and 2, respectively.

Application of elemental analysis-coupled isotope ratio mass spectrometry for protein turnover analysis using deuterium labeling: Purification and analysis of hydrogen isotope ratio of non-derivatized protein-bound alanine.

Heavy water can be used as a tracer for the evaluation of protein turnover. By adding heavy water (D2 O) to the precursor pool, nonessential amino acids, including alanine, can be isotopically labeled in vivo. Protein turnover can then be quantified by measuring the hydrogen isotope ratio of protein-bound alanine. In this study, we constructed a novel method to apply deuterium labeling of alanine to the evaluation of protein turnover using elemental analysis-coupled isotope ratio mass spectrometry (EA-IRMS). We established a preparative high-performance liquid chromatography method to isolate alanine from protein hydrolysates. EA-IRMS was then used to determine the hydrogen isotope ratio of alanine isolated from hydrolysates of protein from mouse myoblast C2C12 cells that had been treated with D2 O over the course of 72 h. In cells treated with 4% D2 O, the deuterium enrichment of alanine increased to approximately 0.9% over time, while that of cells treated with 0.017% D2 O increased to approximately 0.006%. The rate of protein synthesis calculated by fitting the increase of deuterium excess to rise-to-plateau kinetics was similar regardless of the concentration of D2 O. When C2C12 cells treated with insulin and rapamycin were analyzed 24 h after the addition of 0.017% D2 O, protein turnover was found to be accelerated by insulin, but this effect was offset by co-treatment with rapamycin. The derivative-free measurement of the hydrogen isotope ratio of protein-bound alanine using EA-IRMS can be applied to the evaluation of protein turnover. The proposed method is an accessible option for many laboratories to perform highly sensitive IRMS-based evaluations of protein metabolic turnover.

On the Use of Orthoformates as an Efficient Approach to Enhance the Enzymatic Enantioselective Synthesis of (S)-Ibuprofen

In this paper, we describe the effectiveness of the combination between an organic solvent system mixture with orthoformates with different chain sizes from one to four carbon atoms. These orthoesters have been used as a “water trapper/alcohol releaser molecule” to reach a notable improvement in enantioselectivity and enantiomeric excess of our target compound, (S)-2-(4-isobutylphenyl)propanoic acid (ibuprofen eutomer), during the enzymatic kinetic resolution of rac-ibuprofen using immobilized lipase B of Candida antarctica as a biocatalyst. At the same time, one of the great problems of biocatalysis in organic media has been solved by eliminating excess water in the medium that allows the reversibility of the reaction. Following the optimization of the reaction conditions, an increase in enantiomeric excess and enantioselectivity was reached by using these acyl donors in the presence of a cosolvent.

Thermodynamic Simulation of Producer Gas Combustion from Biomass Gasification

The use of new and renewable energy for the application on gas burners is beneficial for the environment. This study aims to determine the effect of excess air during the combustion of producer gas from biomass gasification to release heat used as a fuel gas burner. Simulations are carried out by applying mass and energy balance, showing that an increase in excess air will decrease the non-adiabatic and adiabatic flame temperature. The result showed that an increase in excess of air reduces the amount of heat released to the environment for the same flame temperature. The maximum adiabatic flame temperature is at 1725.430C, while the non-adiabatic ranges from 600 to 8000C. Furthermore, heat is released in the range of 20.1 kW to 28.8 kW, and excess air from 0 to 40%.

An analysis of the effect of gas turbine compressor air preheating on the technical and economic indicators of a PGU-450 unit

We study the effect of preheating the air entering a gas turbine compressor using a standard closed air heating circuit system with heat supply from the heat network of the Urengoy city district power plant on the efficiency of a PGU-450 unit and this power plant as a whole. An analysis was conducted to compare the data obtained as a result of assessing the existing plant characteristics of GTE-160 gas turbines (SGT5-2000E), the adopted operating modes of air heating systems (closed air heating circuit and anti-icing system) and the effect of the operation of these systems on the specific fuel consumption of a PGU-450 unit and the Urengoy city district power plant according to the daily calculated technical and economic parameters of the power unit operation. As a result of full-scale tests carried out with the air heating system at the nominal load of a PGU-450 power unit, the optimal temperature was established to be +6.4°C. During the air heating from -5.0°C to +6.4°C, the specific consumption of the conventional fuel per 1 kWh of electricity decreased by 1.4 g. The reduced specific consumption of the conventional fuel for the supply of electric energy at an increase in the extraction ratio comprised 2.43 and 2.35 g for the equipment of the backup thermal power station and the power plant as a whole, respectively. Thus, the use of a closed air heating circuit with the unutilized network water heating leads to a positive thermal efficiency effect. The preheating of the air entering the gas turbine compressor leads to an increase in its efficiency by 0.3%. A further increase in excess of the optimum temperature leads to a decrease in the available capacity of the combined cycle plant by 3.1 MW per each degree.

Enhancement of Room-Temperature Low-Field Magnetoresistance in Nanostructured Lanthanum Manganite Films for Magnetic Sensor Applications.

The results of colossal magnetoresistance (CMR) properties of La1-xSrxMnyO3 (LSMO) films grown by the pulsed injection MOCVD technique onto an Al2O3 substrate are presented. The grown films with different Sr (0.05 ≤ x ≤ 0.3) and Mn excess (y > 1) concentrations were nanostructured with vertically aligned column-shaped crystallites spread perpendicular to the film plane. It was found that microstructure, resistivity, and magnetoresistive properties of the films strongly depend on the strontium and manganese concentration. All films (including low Sr content) exhibit a metal–insulator transition typical for manganites at a certain temperature, Tm. The Tm vs. Sr content dependence for films with a constant Mn amount has maxima that shift to lower Sr values with the increase in Mn excess in the films. Moreover, the higher the Mn excess concentration in the films, the higher the Tm value obtained. The highest Tm values (270 K) were observed for nanostructured LSMO films with x = 0.17–0.18 and y = 1.15, while the highest low-field magnetoresistance (0.8% at 50 mT) at room temperature (290 K) was achieved for x = 0.3 and y = 1.15. The obtained low-field MR values were relatively high in comparison to those published in the literature results for lanthanum manganite films prepared without additional insulating oxide phases. It can be caused by high Curie temperature (383 K), high saturation magnetization at room temperature (870 emu/cm3), and relatively thin grain boundaries. The obtained results allow to fabricate CMR sensors for low magnetic field measurement at room temperature.

Blood Inflammatory, Hydro-Electrolytes and Acid-Base Changes in Belgian Blue Cows Developing Parietal Fibrinous Peritonitis or Generalised Peritonitis after Caesarean Section.

This study aimed to describe the inflammation, hydro-electrolyte and acid-base imbalances caused by generalised peritonitis (GP) and parietal fibrinous peritonitis (PFP) after caesarean section. After clinical examination, blood was sampled from 11 cows with PFP, 30 with GP and 14 healthy cows. Serum and plasma refractometry and glutaraldehyde tests were used to evaluate the inflammation level, while hydro-electrolytes and acid-base parameters were assessed using an EPOC® device. In addition to clinical signs of dehydration (>10%), blood analysis showed a high fibrinogen concentration (PFP: 8.64 ± 8.82 g/L; GP: 7.83 ± 2.45 g/L) and fast glutaraldehyde coagulation (<3 min) indicative of severe inflammation in both diseases compared to the control group (p < 0.05). Moreover, a severe decrease in electrolytes concentration (Na+: 126.93 ± 5.79 mmol/L; K+: 3.7 ± 1.3 mmol/L; Ca++: 0.89 ± 0.12 mmol/L; Cl−: 82.38 ± 6.45 mmol/L) and a significant increase in bicarbonate (30.87 ± 8.16 mmol/L), base excess (5.71 ± 7.42 mmol/l), L-lactate (8.1 ± 4.85 mmol/L) and creatinine (3.53 ± 2.30 mg/dL) were observed in cows with GP compared to the control group (p < 0.05). In contrast, few major perturbations were noticed in PFP, where only K+ (3.64 ± 0.25 mmol/L) and Ca++ (1.06 ± 0.09 mmol/L) were significantly modified (p < 0.05). In conclusion, a high dehydration and severe inflammation are induced by PFP and GP. Nevertheless, GP causes more electrolytes and acid-base disturbances than PFP.

Synthesis and Preservation of Organic Molecules with Homochiral Excess by Adsorption on Carbon in Carbonaceous Chondrites

The nature of carbon, initial components, molecules of homochiral abiogenic synthesis and their preservation from decay and racemization for more than 4.5 billion years in carbonaceous chondrites has not been established. In the oxygen-free atmospheres of the nebula and early Earth, hydrogen and hydrogen-containing gases were oxidized with carbon monoxide and carbon dioxide to form carbon and water, as well as the intermediates of these reactions, formaldehyde and methane acid. Together with ammonia, they were the initial components of organic synthesis. According to the Rebinder rule, carbon adsorbs hydrogen well, including in organic molecules. In this connection, experiments with the assumed conditions of the early Earth were carried out by adsorption on carbon to obtain R-(rectus, Latin) ribose from formaldehyde, and S-(sinister) serine from formaldehyde, methane acid and ammonia. For other S-amino acids, a stereo chemical justification of their formation based on S-serine is given. For carbonaceous chondrites, the results of the above experiments were confirmed by the correlation of an increase in homochiral excess with an increase in the amount of hydrogen in aldonic acids and lactic acid with a coefficient of 0.94 and 0.85 in amino acids. The justification of the homochiral process will reduce the costs of searching for life on planets, for scientific research, for the production of medicines, perfumes, food, and so on. Doubts about the extraterrestrial origin of homochiral enantiomers in carbonaceous chondrites arise most often due to a lack of understanding of the reasons for their appearance. This work will significantly reduce such skepticism.

Carbon footprint of the Brazilian diet.

ABSTRACTOBJECTIVE:To estimate the carbon footprint of the Brazilian diet and of sociodemographic strata of this population.METHODS:Carbon footprint of the diet was estimated based on data from two 24-hour diet records, obtained in 2008 and 2009, from a probabilistic sample of the Brazilian population aged 10 years and over (n = 34,003) and on environmental impact coefficients of food and culinary preparations consumed in Brazil (gCO2e/kg). Means with 95% confidence intervals of food consumption (kcal/person/day) and the carbon footprint of the diet (gCO2e/person/day and in gCO2e/2,000kcal) were calculated for the population as a whole and for strata according to sex, age, income, education, macro-regions and Federative Unit. Linear regression models were used to identify significant differences (p < 0.05) in the dietary carbon footprint of different sociodemographic strata.RESULTS:The average carbon footprint of the Brazilian diet was 4,489gCO2e/person/day. It was higher for males, for the age group from 20 to 49 years and for the North and Midwest regions, and tended to increase with income and education. The pattern of association of footprint with sociodemographic variables did not change substantially with adjustment for differences in the amount of food consumed, except for a reduction in the relative excess of the footprint among males and an increase in the relative excess of the footprint in the Midwest region.CONCLUSION:The carbon footprint of the Brazilian diet exceeds by about 30% the footprint of the human diet, which could simultaneously meet the nutritional requirements of a healthy diet and the global goal of containing the increase in the planet's average temperature. The pattern of association of this footprint with sociodemographic variables can help identify priority targets for public actions aimed at reducing the environmental impacts of food consumption in Brazil.

Higher total white blood cell and neutrophil counts are associated with an increased risk of fatal stroke occurrence: the Guangzhou biobank cohort study

BackgroundChronic inflammatory diseases are linked to an increased risk of stroke events. The white blood cell (WBC) count is a common marker of the inflammatory response. However, it is unclear whether the WBC count, its subpopulations and their dynamic changes are related to the risk of fatal stroke in relatively healthy elderly population.MethodsIn total, 27,811 participants without a stroke history at baseline were included and followed up for a mean of 11.5 (standard deviation = 2.3) years. After review of available records, 503 stroke deaths (ischaemic 227, haemorrhagic 172 and unclassified 104) were recorded. Cox proportional hazards regression was used to assess the associations between the WBC count, its subpopulations and their dynamic changes (two-phase examination from baseline to the 1st follow-up) and the risk of fatal all stroke, fatal ischaemic stroke and fatal haemorrhagic stroke.Results(i) Regarding the WBC count in relation to the risk of fatal stroke, restricted cubic splines showed an atypically U-curved association between the WBC count and the risk of fatal all stroke occurrence. Compared with those in the lowest WBC count quartile (< 5.3*10^9/L), the participants with the highest WBC count (> 7.2*10^9/L) had a 53 and 67% increased risk for fatal all stroke (adjusted hazard ratio [aHR] = 1.53, 95% confidence interval (CI) 1.16–2.02, P = 0.003) and fatal haemorrhagic stroke (aHR = 1.67, 95% CI 1.10–2.67, P = 0.03), respectively; compared with those in the lowest quartile (< 3.0*10^9/L), the participants with the highest NEUT count (> 4.5*10^9/L) had a 45 and 65% increased risk for fatal all stroke (aHR = 1.45, 95% CI 1.10–1.89, P = 0.008) and fatal ischaemic stroke (aHR = 1.65, 95%CI 1.10–2.47 P = 0.02), respectively. With the additional adjustment for C-reactive protein, the same results as those for all stroke and ischaemic stroke, but not haemorrhagic stroke, were obtained for the WBC count (4 ~ 10*10^9/L) and the NEUT count (the NEUT counts in the top 1% and bottom 1% at baseline were excluded). (ii) Regarding dynamic changes in the WBC count in relation to the risk of fatal stroke, compared with the stable group (− 25% ~ 25%, dynamic changes from two phases of examination (baseline, from September 1st, 2003 to February 28th, 2008; 1st follow-up, from March 31st 2008 to December 31st 2012)), the groups with a 25% increase in the WBC count and NEUT count respectively had a 60% (aHR = 1.60, 95% CI 1.07–2.40, P = 0.02) and 45% (aHR = 1.45, 95% CI1.02–2.05, P = 0.04) increased risk of fatal all stroke occurrence.ConclusionsThe WBC count, especially the NEUT count, was associated with an increased risk of fatal all stroke occurrence. Longitudinal changes in the WBC count and NEUT count increase in excess of 25% were also associated with an increased risk of fatal all stroke occurrence in the elderly population.

Tandem cardiovascular system modelling and machine learning for improved heart failure phenotyping.

Tandem cardiovascular system modelling and machine learning for improved heart failure phenotyping.

Thermo-gas dynamics affect the leaf canopy shape and moisture content of aquaponic lettuce in a modified partially diffused microclimatic chamber

Precise and timely monitoring of leaf water content and growth is necessary for precision agriculture. In this study, the impact of temperature and gas concentration variations was synthesized with leaf canopy shape and moisture content of aquaponic lettuce in a customized partially diffused microclimatic chamber equipped with an RGB camera. Using the acquired thermo-gas sensor data during the light-dependent photosynthetic reaction and dark-period aerobic respiration, it was analyzed with the extracted spectro-morphological leaf canopy signatures. Applying spectro-morphological leaf canopy data as input to the recurrent neural network it was possible to sensitively predict full moisture content (FMT) and equivalent water thickness (EWT) with 92.34% and 85.96% accuracy, respectively. A decrease in red green blue vegetation index (RGBVI) and an increase in excess of green (ExG) optical vegetation stress index corresponds to an increase in FMT. According to our data, it was possible to observe that the water content balance during the third week after sowing, follows the same trend observed for the oxygen production increase during the light period. Additionally, it was also possible to observe that uneven leaf broadening (canopy shape index > 1), low EWT, high photosynthetic quotient (PQ), and photothermal unit (PTU), and minimal temperature and humidity stretch resulted in higher oxygen production rates. A growing degree day of 23.46 ± 0.30 °C day is ideal for aquaponic lettuce. Plants with six (6) weeks exhibited the highest thermal sensitivity (Q1) of 0.205. Overall, the developed model and observations allow concluding that the combined temperature-O2CO2 dynamics monitoring must be considered to achieve maximum production rates. Moreover, in the framework of the new approaches developed within precision agriculture schemes, the collected optical data allied to the recurrent neural network are suitable tools for this continuous monitoring in an automated way.

Crystal and Magnetic Structure Transitions in BiMnO3+δ Ceramics Driven by Cation Vacancies and Temperature.

The crystal structure of BiMnO3+δ ceramics has been studied as a function of nominal oxygen excess and temperature using synchrotron and neutron powder diffraction, magnetometry and differential scanning calorimetry. Increase in oxygen excess leads to the structural transformations from the monoclinic structure (C2/c) to another monoclinic (P21/c), and then to the orthorhombic (Pnma) structure through the two-phase regions. The sequence of the structural transformations is accompanied by a modification of the orbital ordering followed by its disruption. Modification of the orbital order leads to a rearrangement of the magnetic structure of the compounds from the long-range ferromagnetic to a mixed magnetic state with antiferromagnetic clusters coexistent in a ferromagnetic matrix followed by a frustration of the long-range magnetic order. Temperature increase causes the structural transition to the nonpolar orthorhombic phase regardless of the structural state at room temperature; the orbital order is destroyed in compounds BiMnO3+δ (δ ≤ 0.14) at temperatures above 470 °C.

Experimentally Calculated Study of the Effectiveness on the Process of Non-Catalytic Synthesis of Biodiesel in Reactors of Various Type

It was experimentally established that the dependence of the partial pressure of methanol on the molar fraction of methanol in oil shows a pronounced negative deviation from Raoul’s law, which significantly changes the idea of the influence of a large excess of methanol during non-catalytic synthesis of biodiesel. The efficiency of use of a molar excess of methanol is reduced as it grows, and with a more than 10-fold molar excess of the amount of reacted methanol, is practically constant. The comparison of biodiesel production processes in the range 220–235 °C showed that a slight change in the process temperature more effectively affects the biodiesel yield than an increase in the molar excess of methanol. A mathematical model of the process of transesterification of rapeseed oil in reactors of various types (batch and tubular reactors) is developed. A satisfactory correlation between the experimental and calculated data was observed. The calculation showed that the rate constants of the reverse reactions at 230 °C were not significant.

Foam fractionation for effective removal of Pseudomonas aeruginosa from water body: Strengthening foam drainage by artificially inducing foam evolution

Lack of microbial contamination is of great significance to drinking water safety and water reclamation. In this work, foam fractionation was employed to remove Pseudomonas aeruginosa (P. aeruginosa) from aqueous solution and dodecyl dimethyl betaine (BS12) was used as the collector. Since the attachment of strain cells on the bubble surface would impede the reflux of interstitial liquid in the plateau borders (PBs), a novel strategy in strengthening foam drainage was developed through artificially inducing foam evolution. Two gas distributors with different pore diameters had been mounted at the bottom of the column for regulating the radial distribution of bubble size in the foam phase. Experimental results indicated that gas diffuse and bubble coarsening could be significantly promoted by increasing the size difference among the adjacent bubbles. Bubble coalescence contributed to broadening the width of plateau borders, thereby avoiding the borders blockage by strain cells. During bubble coalescence, surfactant molecules would be partially shifted from the surface of small bubble towards that of large bubble due to the molecule density difference. The increase in surface excess of surfactant molecules on gas-liquid interface was conducive to improving foam stability. Under the suitable conditions of air flow rates of gas distributor with 0.125 mm of pore diameter 75 mL/min and gas distributor with 0.425 mm of pore diameter 125 mL/min, BS12 concentration 0.1 g/L, and P. aeruginosa concentration 2.0 × 104 CFU/mL, the removal percentage and enrichment ratio of P. aeruginosa were 99.6% and 10.6, respectively. This work is expected to provide some new light for strengthening foam drainage in the presence of solid particles and to facilitate the industrialization of foam fractionation in water treatment.

The Influence of a Tuition Fee Increase on the Drop-out Rate of the Nursing Program

The aim of the study is to further delve into the question of whether an increase in tuition fee could have a significant impact on the positive outcome of the sacrifice-for-gain assessment among Nursing students. We used an SPSS17.0 to analyze data from an anonymous survey of 160 Nursing students from March of 2016. The results show that the majority of students consider the current tuition fee to be “too high”. An increase in excess of 30% of the tuition fee would lead to a drop of 68.8% or more in the percentage of students willing to continue their education. In order to determine the impact of a tuition fee increase on the respondents’ decision to drop out, three models were tested: 1) the drop-out rate is linearly dependent only on the degree of the tuition fee increase; 2) the drop-out rate depends on multiple factors such as tuition fee increase, year of study, and intrinsic motivational factors; and 3) the drop-out rate depends on intrinsic motivational factors. The models without the variable tuition fee have more predictive power. The study found that only 4% of the drop-out decision is motivated by a potential increase in tuition fee.