On the location of different titanium sites in Ti–OMS-2 and their catalytic role in oxidation of styrene

Octahedral manganese oxide molecular sieves (OMS-2) modified by impregnation of TiO₂ exhibit a higher catalytic activity for oxidation of styrene with tert-butylhydroperoxide in comparison to titanium-incorporated OMS-2, where the styrene conversions were ca. 70% and 45–50%, respectively. The framework of titanium species has no effect on the enhancement of catalytic activity, while the non-framework of titanium species induces a synergetic effect that enhances the oxidation of styrene with tert-butylhydroperoxide.     

Monte Carlo simulation of diffusive-to-ballistic transition in phonon transport

Heat conduction properties in Si nanostructures are analyzed using a Monte Carlo method developed for solving the phonon Boltzmann transport equation. The thermal resistances are evaluated for the systems with various sizes, and the transition from the diffusive to the ballistic heat conduction are investigated. We compare the two different phonon dispersion models (the realistic dispersion relation based on the adiabatic bond charge model and the analytically approximated model), and it is shown that the correct implementation of the phonon dispersion relation is essential to accurately simulate the quasi-ballistic heat conduction properties, which becomes obvious in the structures smaller than the phonon mean free path.     

Non-Newtonian laminar pulsating heat and fluid flow in plane duct

In the present study, laminar pulsating power-law momentum and heat transfer in a uniformly heated plane duct is studied analytically. Assuming that fully developed conditions exist both hydrodynamically and thermally, a perturbation series method is utilized to derive analytical solutions for the momentum and energy balance equations, and the amplitude is prescribed as the perturbation parameter. For varying values of the power-law index ( $n$), representing pseudoplastic, Newtonian, and dilatant fluids, effects of dimensionless amplitude ( $ϵ$) and frequency ( $F$) on periodic and period-averaged friction factor and Nusselt number are obtained. The results obtained for Newtonian fluid are shown to be in good harmony with the corresponding findings in the open literature.     

Rapid Detection of Wheat Blast Pathogen Magnaporthe oryzae Triticum Pathotype Using Genome-Specific Primers and Cas12a-mediated Technology

Wheat blast, caused by the fungus Magnaporthe oryzae Triticum (MoT) pathotype, is a devastating disease persistent in South America and Bangladesh. Since MoT generally fails to cause visual symptoms in wheat until the heading stage when the infection would have advanced, disease control by fungicide application solely based on the detection of visual symptoms is ineffective. To develop an accurate and sensitive method to detect MoT at the seedling and vegetative stages for disease control, we sequenced the genomes of two MoT isolates from Brazil and identified two DNA fragments, MoT-6098 and MoT-6099, that are present in the MoT genome but not in the genome of the rice-infecting Magnaporthe oryzae Oryzae (MoO) pathotype. Using polymerase chain reaction (PCR), we confirmed the specificity of the two markers in 53 MoT and MoO isolates from South America and Bangladesh. To test the efficiency of the two markers, we first established a loop-mediated isothermal amplification (LAMP) method to detect MoT at isothermal conditions, without the use of a PCR machine. Following this, we used the Cas12a protein and guide RNAs (gRNAs) to target the MoT-6098 and MoT-6099 sequences. The activated Cas12a showed indiscriminate single-stranded deoxyribonuclease (ssDNase) activity. We then combined target-dependent Cas12a ssDNase activation with recombinase polymerase amplification (RPA) and nucleic acid lateral flow immunoassay (NALFIA) to develop a method that accurately, sensitively, and cost-effectively detects MoT-specific DNA sequences in infected wheat plants. This novel technique can be easily adapted for the rapid detection of wheat blast and other important plant diseases in the field.     

Fermentation and oxygen transfer characteristics in serine alkaline protease production by recombinant Bacillus subtilis in molasses‐based complex medium

Serine alkaline protease (SAP) production in a complex medium based on physically pretreated molasses by recombinant Bacillus subtilis carrying pHV1431::subC gene is described. The effects of oxygen transfer were investigated in 3.5 dm³ bioreactor systems with controls for agitation rate, dissolved oxygen, pH, temperature, and foam formation under two different agitation rates, ie N = 500 and 750 min^?1, and four different air flow rates, ie Q/V_R = 0.2, 0.5, 0.7, and 1.0 vvm, at a molasses concentration equivalent to initial sucrose concentration (C_So) of 20 kg m^?3. The yield values (Y_X/S, Y_X/O, Y_S/O) and maintenance coefficient of oxygen (m_O), were calculated. m_O decreased with the increase in the air‐inlet rate. Increase in oxygen transfer rate increased the rate of growth and SAP activity, and affected the cultivation time to achieve maximum expression of SAP activity. At Q/V_R = 0.5 vvm and N = 750 min^?1, SAP activity reached 2250 U cm^?3 at t = 36 h. The oxygen transfer coefficient (K_La) and oxygen uptake rate (?r_O) were measured throughout the fermentations and their variation with the oxygen transfer conditions determined. New correlations for the calculation of K_La and ?r_O are proposed. Copyright © 2004 Society of Chemical Industry     

Phthalate Sample Preparation Methods and Analysis in Food and Food Packaging: a Review

A review on phthalate esters or phthalic acid esters (PAEs), chemicals of concern since a few decades ago that are widely used as plasticizers in food processing and packaging, is presented taking into account the background of such compounds, the metabolism, human exposure to PAEs, the sources and occurrence in food as well as the toxicological aspects and human health effects. In addition, 45 novel research articles that were published between 2002 and 2017 were identified and their results were tabulated showing the PAEs analysed, food matrix of PAEs, methods of sample preparation/extraction, methods of instrumental analysis and quantitation, percentage recovery and limit of detection (LOD) of the instrument for ease of comparison and referencing. In general, it was found that in the last 15 years, the number of PAEs analysed has increased from the commonly analysed 8 PAEs, namely dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DIBP), di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBP), dicyclohexyl phthalate (DCHP), di-n-octyl phthalate (DNOP) and di-(2-ethylhexyl) phthalate (DEHP) to as many as 23 PAEs. The methods of sample preparation have also progressed from the simple liquid-liquid extraction using organic solvents to solid-phase microextraction techniques to the more recent head-space or direct immersion solid-phase microextraction methods. Whereas for the analysis of PAEs, gas chromatography and liquid chromatography are still the preferred methods with improved LOD of analysis ranging from approximately 10 ppm for fatty foods to 1–60 ppt for water, juices and cooking oil samples.     

Storage of spinach juice agglomerates: Physical,flow, structural,and thermal properties

The objective of this study was to investigate how the various storage temperatures affected the physical properties, flow characteristics, microstructure, and glass transition temperature of spinach juice agglomerates. For this purpose, spray-dried spinach juice powders were processed to agglomerates by using a modified fluidized bed dryer (1.6 m/s airflow rate, 60°C drying air temperature, 20 min processing time, and with different binder solutions containing agents as maltodextrin, gum Arabic, and whey powder isolate). The analyses were carried out every month throughout 6 months while the spinach juice agglomerates were stored at temperatures of 4, 20, and 35°C. The results revealed that over the storage time, the moisture content and water activity values of the agglomerates were generally under 11% and 0.6, respectively. The color values generally showed a decreasing trend depending on the storage time. The solubility times of the samples stored at 4°C were longer than those of stored at other storage temperatures. The SJA-GA had the lowest HR and CI values and thus the best flowability properties during all storage times. There was no detectable change in the structures of SJA stored at 20°C according to the storage time. Throughout the storage time, it was discovered that the glass transition temperature of all spinach juice agglomerates was remarkably similar. Overall, the investigation revealed that storage at 35°C for 6 months might be suitable because it delivered the intended outcomes such as greater flowability and cohesiveness, and shorter wettability and solubility times.