High-yield Method Research Articles

A green chemistry approach for facile synthesis of functionalized boron nitride nanosheets

The lack of a high-yield, renewable and low-cost synthesis method limits the potential applications of boron nitride with impressive characterizations. In this study, a facile method is developed for the preparation of chemically functionalized boron nitride nanosheets (BNNSs) by considering the quantity and quality of chemical materials involved in the synthesis process. The proposed green method is a suitable and high-efficiency method for replacing other production methods of BNNSs. Ultrathin BNNSs is produced by chemical reactions and subsequent liquid exfoliation. The possibility of chemical reaction is the highest at the defect sites especially at the upper/lower surfaces as well as the edge of bulk material. Due to hydroxyl functional groups that are coupled to the surface during the synthesis, the obtained products can well be dispersed in polar solutions such as water, ethanol, acetone and isopropyl alcohol. AFM, TEM, and SEM techniques are utilized to confirm the quality of the used method and illustrated that the produced-BNNSs have minimum thicknesses in the range of 1–5.6 nm and with lateral sizes ranging from 0.8–2.5 μm. The existence of functional groups and the structure of the BNNSs are verified by FTIR, EDX, XPS, XRD and Raman analyses. It was seen that the hexagonal structure was retained during the functionalization procedure. One can expect that the functionalization and sonication process introduces functional groups onto the surface of BNNSs. By this method, the obtained yield of BN dispersion is improved up to 17-20%.

High-Quality and High-Yield RNA Extraction Method From Whole Human Saliva.

Background:Human saliva has been identified as a novel, practical, and noninvasive source of biomarkers and genetic materials. However, it is equally challenging due to the availability of an abundance of impurities in the form of microbes and other proteinaceous compounds. The objective of this study was to develop a robust, reproducible, and economic method of extracting high-yield and high-quality RNA from whole human saliva.Methods:The modified TRIzol protocol was developed to extract RNA from saliva (n = 14), followed by complementary DNA synthesis and reverse transcription quantitative polymerase chain reaction analyses for the genes encoding IL1B, ALPL, RUNX2, and ACTB. To compare our protocol with the spin column–based method, we used Qiagen Salivary Protect Micro-RNA spin columns (n = 6). To evaluate and compare the yields and quality of extracted RNAs from both methods, we used (1) Experion Bioanalyzer, (2) QuantiFluor RNA dye, and (3) NanoDrop 2000 Spectrometer.Results:With the modified TRIzol lysis protocol, a high yield of total RNA, on average 12.34 μg, from saliva was extracted compared with on average 0.2 μg with a spin column–based method. The average RQI (RNA quality index) with the TRIzol method was 7.86, which is also comparable with that of the spin column–based method (RQI = 7.58). QuantiFluor dye used for RNA quantification showed a 16-fold higher yield of RNA concentration using our TRIzol protocol.Conclusions:Our modified TRIzol protocol is a reproducible method to extract RNA from whole human saliva which can be used for gene expression analysis. This method allows also ensures the quality of RNA required for specific applications such as RNA sequencing.

Key Stratum Structure and Support Working Resistance of Longwall Face with Large Mining Height in the Shallow Coal Seams, China

The fully mechanized mining with large mining height is the main method for high yield and efficient coal mining in China. The key stratum structure (KSS) is the basis of revealing the mechanism of roof weighting and determination of support working resistance of the longwall face with large mining height (LFLMH) in the shallow coal seam. The height of the caving zone at LFLMH is large, the thick immediate roof forms the “short cantilever beam” structure commonly, and the hinge layer of the overlying key stratum will move upward to the higher position. The “high position oblique step voussoir beam” structure of single‐key stratum (SKS) and “oblique step voussoir beam and voussoir beam” structure of double‐key stratum (DKS) in the shallow coal seam were proposed with physical simulation and Universal Distinct Element Code (UDEC). The analysis of the KSS and numerical simulation reveals the mechanism of strong roof weighting at the SKS longwall face and large‐small alternate periodic weighting at the DKS longwall. It is concluded that the large static load caused by the “equivalent immediate roof (EIR)” is the basic load, and the instability load of the KSS is the additional dynamic load of support. Besides, the calculation methods of the reasonable support working resistance at LFLMH were obtained and verified with engineering applications.

Preparation of silver nanoparticles and application in water-based conductive inks

We reported a simple, high yield and large-scale preparation method for silver nanoparticles. Silver nanoparticles with 8–13 nm in diameter were successfully synthesized by silver nitrate as raw material, sodium borohydride as reducing agent, dispersan-5040 (polycarboxylate sodium salt) as surface modifier in aqueous solution. The effects of sodium borohydride and dispersan-5040 on the morphologies of silver nanoparticles were investigated. Further, the conductive inks were prepared with as-synthesized silver nanoparticles as conductive fillers in the presence of deionized (DI) water and additives. The effects of conductive fillers and additives on the pH, conductivity, surface tension and viscosity of the inks were investigated. The conductive patterns were fabricated by inkjet printer and their performances were studied. The sheet resistances of the printed pattern with seven-layer was 1.2 [Formula: see text] when the printed pattern was heat-treated at 120[Formula: see text]C for 60 min. We succeeded in printing a simple conductive circuit on photographic paper, which can light three 0.06 W LED beads. The successful fabrication of the functional circuit proves the feasibility of the ink and provides some ideas for future paper-based circuits.

A Solid-State Fluorescence Sensor for Nitroaromatics and Nitroanilines Based on a Conjugated Calix[4]arene Polymer.

A new conjugated polymer possessing calix[4]arene-oxacyclophane units wired-in-series by phenyleneethynylene linkers was synthesized by a Sonogashira-Hagihara cross-coupling method in high yield. The polymer was structurally characterized by FTIR and 1H/13C/HSQC NMR techniques, and its average Mn (38.5kDa) retrieved from GPC analysis. The polymer is highly emissive (ΦF = 0.55) and exhibits a longer-than-usual excited-state lifetime (1.80ns) for a phenyleneethynylene type polymer. Similar photophysical properties (absorption and fluorescence emission) were observed in solution and in solid-state. This stems from the presence of bulky calixarene moieties along the polymer chains which prevent interchain staking and the formation of ground-state aggregates and/or non-emissive exciplexes, both deleterious to solid-state materials envisioned for fluorescence sensing applications. Moreover, the intrinsic molecular recognition capabilities of its two rigid inner cavities (calixarene and cyclophane sub-units), allied with the high three-dimensionality of the macromolecule that creates additional interstitial voids around the molecular receptors, can boost its sensory responses towards specific analytes. A high sensitive response was observed in the detection of nitroaromatics and nitroanilines in neat vapour phases by casted films of the polymer. The largest sensitivities were obtained for 2,4-dinitrotoluene (a taggant for the explosive TNT; > 85% of fluorescence quenching upon 1min exposure) and ortho-nitroaniline (90% of emission reduction in 30s). The sensory responses attained in solid-state are discussed on the basis of the electron affinities of the analytes and their electrostatic interactions with polymer films. Graphical Abstract Sensing the threats! A high sensitive response was observed in the detection of explosives and noxious nitroanilines in neat vapour phases by thinfilms of a calixarene-based polymer.

Gram-Scale Synthesis of 3-Sulfonyl Flavanones.

In this paper, an easy-operational, high-yielding method for the gram-scale synthesis of 3-sulfonyl flavanones is described by a one-pot straightforward POCl3 mediated intermolecular (5 + 1) annulation of the β-ketosulfones with an o-hydroxyaryl group (dual nucleophile) and arylaldehydes (dual electrophile) in refluxing toluene for 3 h. A plausible mechanism is proposed and discussed. This protocol provides a highly effective annulation via one carbon-oxygen (C-O) and one carbon-carbon (C-C) bond formations.

Lipase-Catalyzed Highly Efficient 1,6-Conjugated Addition for Synthesis of Triarylmethanes

Lipase from porcine pancreas (PPL) is first reported to catalyze direct 1,6-conjugated addition for synthesis of triarylmethanes using p-quinonemethides (p-QMs) and 2-naphthols. The catalytic activity of PPL was evaluated through investigating the solvent, the ratio of substrates, the enzyme loading and the temperature of the enzyme-catalyzed reactions. The present method proves to be environmentally friendly and efficient in terms of high yield, green catalyst and simple synthesis method.

A high yield method for the direct amidation of long‐chain fatty acids

AbstractThe amidation of long‐chain fatty acids is the key step for preparing surfactants with excellent interfacial activity. Gas chromatography–mass spectrometry was employed to detect the reactants and products in the direct amidation reactions. The conversion and the concentration of the amides in the reaction process were also investigated to determine the best catalyst, the reaction rate constants, and activation energy. It was identified that the amidation reaction of the long‐chain phenyl fatty acid was a zero‐order reaction and 3,4,5‐trifluorophenylboronic acid was the most effective catalyst by which the activation energy reduced to 55.79 kJ/mol from 95.44 kJ/mol. The method can be applied to other long‐chain fatty acids, saturated or unsatureated. The turning‐over‐temperature was 156°C, over which high yields can be achieved without any catalyst. These provide a reference for the preparation of long‐chain fatty acid amides.

Development of the limit values of micronutrient deficiency in soil determined using Mehlich 3 extractant for Polish soil conditions. Part I. Wheat

Abstract To implement the Mehlich 3 method in Polish agro-chemical laboratories, limit values for deficiency of B, Cu, Fe, Mn and Zn in soil for wheat were developed. The values were developed on the basis of 1921 fields with wheat, evenly distributed throughout Poland. Soil samples were collected from these fields in 2016, together with the plants growing on them, at the stage of stem elongation (BBCH 30/31). The concentration of micronutrients was determined in all soil and plant samples. In addition, pH, texture, and the content of organic carbon and available phosphorus were determined in soil samples. Moreover, grain yield after wheat harvest was estimated for all fields. Limit values were developed by two independent methods: 1) the regression equation method and 2) the so-called high yield method. In the first case, the limit microelement concentration in soil was calculated from the equation describing the relationship between the bioaccumulation factor (R/G) and a specific soil feature (n=1921). The bioaccumulation factor is the quotient of the concentration of a micronutrient in a plant (R) and its concentration in the soil (G) determined by the Mehlich 3 method. The equations were constructed using the Stagraphics program. For each micronutrient, 8 models were tested in search for the equation with the highest determination coefficient r2. Limit values were calculated after substituting the critical value of microelements in the plant (R) to the selected model and transforming the equation accordingly. The basis of the second method was to separate the “high yield group” ≥7.0 t ha−1 (n=578) from the entire data set. In this group, lower quintiles for the Mehlich 3-concentration of individual microelements in soil were calculated. The lower quintiles (QU1) were taken as limit values. It was assumed that QU1 is a good indicator of the lowest micronutrient concentration in the soil at which a yield of 7.0 t ha−1 or higher can be obtained. The comparison of the values calculated with the regression equations method and the high yield method showed their similarity, which confirmed the reliability of these values. The proposed values define the limit for low microelements concentration in soil determined with the Mehlich 3 method, below which wheat fertilization with these nutrients is recommended.

Development of the limit values of micronutrient deficiency in soil determined using Mehlich 3 extractant for Polish soil conditions. Part II. Rapeseed

Abstract The aim of the study was to develop limit values for low microelement concentration in the soil, determined with the use of Mehlich 3 extractant for assessing their deficits in rapeseed crops. The values were prepared on the basis of 1944 fields with rapeseed, covering the whole Poland. In 2017, the samplers of Polish agro-chemical laboratories took soil samples and corresponding plant samples at the BBCH 30/31 stage. In the plant samples, the concentration of microelements was determined, and in the soil samples, apart from microelements, also pH, texture and the concentration of organic carbon and available phosphorus, were determined. Moreover, for each field, data on rapeseed yield were collected. Limit values were determined by two independent methods: 1) the method of regression equations and 2) the so-called high yield method. In the first case, the limit microelement concentration in the soil was calculated from the equation describing the relationship between the R/G bioaccumulation coefficient and a specific soil feature (n=1944). The bioaccumulation coefficient is a quotient of the concentration of a microelement in a plant (R) and its concentration in the soil determined by the Mehlich 3 (G) method. Limit values were calculated after substituting the critical concentration of microelements in the plant (R) to the equation, and subsequently, an appropriate conversion of the equation. The second method was based on the separation of a group of high yields ≥4.0 t ha−1 (n=755) from the whole data set. Then in this group, the lower quintiles (QU1) were calculated for the concentration of individual microelements in the soil determined in Mehlich 3 extract and adopted as limit values. It was found that QU1 is a good indicator of the lowest microelement concentration in the soil at which a yield of at least 4.0 t ha−1 can be obtained. The final limit values were worked out by averaging the values calculated by the equations and high yield method and their appropriate correction. In the combined soil sample collections for wheat and rapeseed (n=3865), the values were checked by evaluating the percentage of soils with microelement shortage separately for rape and wheat. The results of this evaluation were compared with the evaluation using the old system based on the 1 M HCl, which did not take into account the plant species.

Design of the Key Bearing Layer and Secondary Mining Technology for Previously Mined Areas of Small Coal Mines

In many underground coal-mine fields, where small scale coal mining had been performed, the available resources were not extracted fully. To extract the remaining coal, it is necessary to perform secondary mining. In this paper, a novel secondary mining technology is suggested incorporating a novel concept of building a key bearing layer (KBL) through backfilling in the previously mined areas to increase the extraction ratio, prolong the mine life, and avoid undesirable impacts on the limited coal resources and ecological environment. To analyze the influence of previously mined areas of small coal mines on the secondary mining, two new methods of determining the thickness of the KBL, choosing of the backfilling material, the slice backfilling method, ABAQUS finite-element analysis, field monitoring of displacement, and secondary mining technology were implemented. The results show that a minimum thickness of 5 m is required for the KBL in B909 panel of Pingshuo No. 2 underground coal mine to ensure stability of both the roof and coal walls during the secondary mining process. Ruimi-backfilling material was used to construct the cutting layer and KBL with different compressive strengths in the previously mined areas to carry out the slice backfilling, which met the mining requirements of the normal coal seam with reduced cost. Numerical simulation results showed that, when the secondary mining face was 20 m away from the previously mined areas, the secondary mining stress overlapped with the stress which was there from the previously mined areas to result in roof collapses. When the secondary mining face approached the previously mined areas, the roof of the goaf had a large area of collapse, which was beneficial to the stability of the KBL. It was possible to use the field-monitored displacements to validate the numerical-modeling results. The proposed novel secondary mining technology with backfilling in the previously mined areas of small coal mines turned out to be a safe, high-yielding and efficient mining method.

Rapid in vitro production of single-stranded DNA.

There is increasing demand for single-stranded DNA (ssDNA) of lengths >200 nucleotides (nt) in synthetic biology, biological imaging and bionanotechnology. Existing methods to produce high-purity long ssDNA face limitations in scalability, complexity of protocol steps and/or yield. We present a rapid, high-yielding and user-friendly method for in vitro production of high-purity ssDNA with lengths up to at least seven kilobases. Polymerase chain reaction (PCR) with a forward primer bearing a methanol-responsive polymer generates a tagged amplicon that enables selective precipitation of the modified strand under denaturing conditions. We demonstrate that ssDNA is recoverable in ∼40–50 min (time after PCR) with >70% yield with respect to the input PCR amplicon, or up to 70 pmol per 100 μl PCR reaction. We demonstrate that the recovered ssDNA can be used for CRISPR/Cas9 homology directed repair in human cells, DNA-origami folding and fluorescent in-situ hybridization.

Bacterial overexpression and purification of soluble recombinant human serum albumin using maltose-binding protein and protein disulphide isomerase

Human serum albumin (HSA), the most abundant serum protein in healthy humans, plays important roles in many physiological processes and has wide clinical and research applications. Despite several efforts to obtain recombinant HSA (rHSA) from bacterial and eukaryotic expression systems, a low-cost and high-yield method for rHSA production is not available. The large molecular weight and high disulphide content hamper the expression and production of rHSA using bacterial hosts. Hence, a strategy that uses a fusion technique and engineered Escherichia coli strains was employed to improve the expression of soluble rHSA in the bacterial cytoplasm. The solubilities of the b'a' domain of human protein disulphide isomerase (PDIb'a')- and maltose-binding protein (MBP)-tagged rHSA expressed in Origami 2 at 18 °C were notably increased by up to 90.1% and 96%, respectively. A simple and efficient protocol for rHSA purification was established and approximately 9.46 mg rHSA was successfully obtained from a 500-mL culture at 97% purity. However, rHSA was mostly obtained in soluble oligomeric form. By introducing a simple refolding and size-exclusion chromatography step, monomeric rHSA was obtained at 34% yield. Native polyacrylamide gel electrophoresis confirmed the similarity in the molecular weights between E. coli-derived monomeric rHSA and commercial monomeric HSA.

High-Purity Boron Nitride Nanotubes via High-Yield Hydrocarbon Solvent Processing

Boron nitride nanotubes (BNNTs) are highly interesting for structural, thermal, and biomedical applications but have, thus, far been limited due to a lack of high-yield methods to produce a purifie...

Rapid and Low-Temperature Salt-Templated Production of 2D Metal Oxide/Oxychloride/Hydroxide.

2D materials have played an important role in electronics, sensors, optics, electrocatalysis, and energy storage. Many methods for the preparation of 2D materials have been explored. It is crucial to develop a high-yield, rapid, and low-temperature method to synthesize 2D materials. A general, fast (5 min), and low-temperature (≈100 °C) salt (CoCl2 ·6H2 O)-templated method is proposed to prepare series of 2D metal oxides/oxychlorides/hydroxides in large scale, such as MoO3 , SnO2 , SiO2 , BiOCl, Sb4 O5 Cl2 , Zn2 Co3 (OH)10 2H2 O, and ZnCo2 O4 . The as-synthesized 2D materials possess an ultrathin feature (2-7 nm) and large aspect ratios. Additionally, these 2D metal oxides/oxychlorides/hydroxides exhibit good electrochemical properties in energy storage (lithium/sodium-ion batteries) and electrocatalysis (hydrogen/oxygen evolution reaction).

ONE-POT SYNTHESES OF 2-(1H-BENZO[d]OXAZOLE-2-YL)-N-ARYLBENZAMIDES BY SELF-CATALYSIS

A novel, efficient, and high-yielding one-pot three-component method was developed for the synthesis of 2-(1 H -benzo[ d ]oxazole-2-yl)-N-arylbenzamides by combining phthaldichloride with anilines and o-aminophenol in water without any external catalyst. The environmentally friendly procedure, easy operation and mild reaction conditions enable the tolerance of a wide scope of functionalities as well as high reaction efficiency.

A novel technique to prepare a single cell suspension of isolated quiescent human hepatic stellate cells

To explore a simple and easy-to-learn procedure for the isolation of human quiescent hepatic stellate cells (HSCs) that requires no advanced training. Thus reducing costs and increasing efficiency. This protocol will provide sufficient primary cells with minimal contaminants for future basic research on diseases associated with human HSCs. Normal liver tissues were isolated from patients undergoing hepatic hemangioma resection, and a single cell suspension of these tissues was prepared using the Gentle MACS tissue processor. By using this method, the difficulty of the procedure was reduced, fewer cells were lost during the preparation treatments, and the maximal activity of single cells was maintained. Following preparation of the cell suspension, the HSCs were further isolated using a Nycodenz density gradient. Cell viability was examined by trypan blue staining, and the purity of the quiescent human HSCs was determined by autofluorescence and oil red O staining. Activated and quiescent human HSCs were identified using immunofluorescence and Western blotting. The cell cycle distribution in activated and quiescent human HSCs was analyzed by flow cytometry.The recovery rate of the HSCs was approximately (2.1 ± 0.23) × 106 of tissue, with 94.43 ± 1.89% cell viability and 93.8 ± 1.52% purity. The technique used in this study is a simple, high-yield, and repeatable method for HSC isolation that is worthy of recommendation.

Synthesis of CuO and ZnO nanoparticles by a novel green route: Antimicrobial activity, cytotoxic effects and their synergism with ampicillin

CuO and ZnO nanoparticles (NPs) were synthesized at room-temperature following a novel, direct, high-yield (>91%) and green method based on a mechanically activated metathesis reaction. The CuO-NPs exhibited a rod-like shape with average length and diameter of 22 and 6 nm, respectively, while the ZnO-NPs showed spherical-like morphology and mean diameter of 15 nm, as determined by TEM. The antimicrobial properties of the NPs and commercially available micrometric counterparts were evaluated by the micro dilutions method to determine the minimum inhibitory concentrations against reference strains from ATCC microorganisms, which were representative of the main groups of bacteria related to human infections, such as E. coli, S. aureus, E. faecalis and P. aeruginosa. The CuO and ZnO-NPs showed better antibacterial properties (500 μg/mL) in comparison with the commercial micrometric particles (1000 μg/mL). The analysis of the synergism between both NPs and ampicillin showed a decrease of their concentrations against all the microorganisms studied, with the ZnO-NPs showing better synergism activity than CuO-NPs, whereas the combination of the antibiotic with ZnO-NPs showed a six-fold decrease against all the microorganisms studied except to P. aeruginosa. The FIC index was calculated with both NPs and ampicillin to each bacterium. In most cases, the effect was partial synergism, and an additive effect was achieved when those combinations were evaluated against P. aeruginosa. The cell viability tests showed that the CuO and ZnO-NPs synthesized and mixed with the antibiotic are biocompatible in effective doses (<25 μg/mL). The NPs used in this study, prepared by a green innovative synthesis, and their combination with a basic antibiotic showed interesting results, suggesting the possibility of one alternative to biological applications.

An Improved Phenotyping Protocol for Panama Disease in Banana.

Fusarium oxysporum (Fo) belongs to a group of soil-borne hyphomycetes that are taxonomically collated in the Fusarium oxysporum Species Complex (FOSC). Hitherto, those infecting bananas were placed in the forma specialis cubense (Foc). Recently, however, these genetically different Foc lineages were recognized as new Fusarium spp. placed in the Fusarium of Banana Complex (FOBC). A member of this complex F. odoratissimum II-5 that uniquely comprises the so-called Tropical Race 4 (TR4), is a major problem sweeping through production zones of Cavendish banana in several regions of the world. Because of this, there is an urgent need for a phenotyping method that allows the screening for resistance to TR4 of large numbers of banana genotypes. Most Fusarium species produce three types of spores: macroconidia, microconidia and the persistent chlamydospores that can contaminate soils for many years. Inoculum production has been an important bottleneck for efficient phenotyping due to the low or variable number of conidia and the elaborate laboratory procedures requiring specific infrastructure. Here, we report a rapid, simple and high-yielding spore production method for nine F. oxysporum formae speciales as well as the biocontrol species Fo47 and Fo618-12. For Fusarium spp. causing Fusarium wilt or Panama disease of banana, we used the protocol for four species comprising the recognized physiological races, including Tropical Race 4 (TR4). We subsequently tested the produced inoculum in comparative inoculation trials on banana plants to evaluate their efficiency. All assays resulted in typical symptoms within 10 weeks; significant differences in final disease ratings were observed, depending on inoculum concentration. Pouring inoculum directly onto banana plants showed the most consistent and reproducible results, as expressed in external wilting, internal discoloration and determined by real-time PCR assays on entire rhizomes. Moreover, this method allows the inoculation of 250 plants per hour by one individual thereby facilitating the phenotyping of large mutant and breeding populations.

Synthesis and properties of Bi2WO6 coupled with SnO2 nano-microspheres for improved photocatalytic reduction of Cr6+ under visible light irradiation

Bi2WO6 coupled with SnO2 nano-microspheres (nSnO2/BWO) with excellent photocatalytic activity for Cr6+ reduction was successfully synthesized via a facile solvothermal-calcining route. The results showed that the coupling of SnO2 to Bi2WO6 caused the shape of the catalyst to have a regular microsphere structure and increased surface adsorption sites, narrowed the band gap, and enhanced the electrical conductivity of the as-prepared composites. The surface structure of the as-prepared composites accelerated carriers' migration, improved the separation and transfer of photogenerated carriers, and enhanced the response of the composite to visible light. The optimal mass ratio of SnO2 to Bi2WO6 was determined to be 7%. The 7SnO2/BWO sample exhibited a high Cr6+ photoreduction rate of 98.2% in 50 min; this is 47.5% higher than that of pure Bi2WO6. Moreover, the photocatalytic oxidation capacity of the as-prepared composites was evaluated to further explain its photocatalytic mechanism, and the maximum degradation rates of tetracycline and rhodamine were found to be 85.9% in 120 min and 94.4% in 40 min, respectively. Thus, this work presents a simple and high-yield method for the synthesis of Bi2WO6 coupled with SnO2 photocatalysts. Given their enhanced photocatalytic activity, the as-prepared composites are promising candidates for Cr6+ reduction and for meeting the requirements of future photocatalytic materials.