Results Of Stability Tests Research Articles

In situ synthetic hierarchical porous MIL-53(Cr) as an efficient adsorbent for mesopores-controlled adsorption of tetracycline

Significant concerns have been raised over the adsorption of tetracyclines from aquatic environments. In this paper, hierarchically porous MIL-53(Cr) was synthesized by in situ synthesis for the first time and the influence of mesopores on tetracycline adsorption was investigated. Benefiting from the high mesoporous volume, more TC molecular could enter the channel to interact with adsorption sites, and the adsorption capacity of 20-AA-MIL-53(Cr) for TC increased twelvefold, up to 148.5 mg/g. In addition, various kinetic models have also been used to investigate the adsorption process of tetracycline. Particularly, considering the molecular size of TC about 12.9 Å × 7.4 Å, Elovich and intraparticle diffusion kinetic models were used to testify that the external mass transfer of TC on 20-AA-MIL-53(Cr) was much higher than that on MIL-53(Cr) when the pore size was expanded to 2–3 nm. What's more, the results of water stability test revealed the excellent water stability of 20-AA-MIL-53(Cr) for over 5 days. This study described a simple method for the preparation of hierarchical porous MIL-53(Cr) and explored the effect of mesopores on the adsorption of TC, so as to propose that hierarchical porous MIL-53(Cr) can be used as a potential adsorbent in water adsorption treatment. • Hierarchical porous x-AA-MIL-53(Cr) was prepared by in situ synthesis for the first time. • 20-AA-MIL-53(Cr) had the highest surface area (2249 m 2 /g) and mesoporous volume (0.62 cm 3 /g). • The adsorption capacity of tetracycline by hierarchical porous MIL-53(Cr) increased twelvefold. • The presence of mesopores allowed more tetracycline molecules to contact the adsorption sites.

Dual function metal-organic frameworks based ratiometric electrochemical sensor for detection of doxorubicin

Cancer is one of the main diseases threatening human health in the world. Doxorubicin (DOX) is a common anti-cancer drug that can be used for chemotherapy to extend a cancer patient's life. It is our common wish that treatment process of cancer is efficient and secure. Therefore, it is of great significance to develop sensitive, rapid and accurate techniques for anti-cancer drug doxorubicin (DOX) detection. Herein, in our work, a ratiometric electrochemical sensor for DOX detection was designed, which based on MB@MWCNTs/UiO-66-NH2 composites. The porous materials UiO-66-NH2 magically shoulder double function in our ratiometric electrochemical strategy, which can reduce the interior error caused by the various complex materials. Specifically, on the one hand, it can be used to catalyze DOX, which can provide a great current signal to be detected, on the other hand, its special property of absorbing molecules was utilized to load materials as internal reference. Consequently, we chose methylene blue (MB) as the substance that can generate an internal reference signal, because it is a specific and stable electroactive substance. Then, we added MWCNTs as a part of the material modified on the ratiometric electrochemical platform to enhance the signal of the target due to its feature of good electrical conductivity. Under the optimized conditions, the ratiometric electrochemical sensor displayed a wide linear detection with the range from 0.1 μM to 75 μM and the limit of detection (LOD) of 0.051 μM. The applicability of this method in the analysis of actual human saliva samples has been confirmed by the results of selectivity, stability, and reproducibility tests, which was prospective in clinical application.

Synthesis of high‐performance bio‐based benzoxazine for flame retardant application

AbstractIn this study, a phosphorous‐containing benzoxazine was synthesized using a bio‐based primary amine, vanillin diamine true sample 2 (VDTS2,IUPAC name: 4‐(([3‐aminopropyl] imino) methyl)‐2‐methoxyphenyl(4‐(([3‐aminopropyl] imino) methyl)‐2‐methoxyphenyl) phenylphosphonate), paraformaldehyde and vanillin and tested for its use as a flame‐retardant. The molecular structure of the synthesized benzoxazines was characterized by FTIR spectroscopy and1H NMR spectroscopy. Polybenzoxazine was obtained through the ring‐opening polymerization of the benzoxazine monomer, and the formation of the same was confirmed through FTIR spectroscopy. The polymerization mechanism of the benzoxazine was investigated using thermogravimetric analysis (TGA). The thermal properties of the benzoxazine were studied using differential scanning calorimetry and TGA. The flame‐retardant properties of the polybenzoxazine films obtained were investigated by the LOI. Due to the highly brittle nature of the polybenzoxazine, the synthesized polybenzoxazine was further crushed and incorporated into an epoxy system to investigate its use as a flame‐retardant additive. The thermal property and flame‐retardant property of the epoxy films were then studied. The flame‐retardant and thermal stability test results of the epoxy‐pbz films showed that the epoxy‐pbz films showed improved thermal stability and achieved a UL‐94 V‐0 rating and an LOI of 28% at 15% by weight of the polybenzoxazine concentration. SEM analysis was also conducted to study the surface morphology of the polybenzoxazine and epoxy‐pbz films pre and post the flame test. FTIR analysis was carried out to study the flame retardant mechanism of the polybenzoxazine and the epoxy‐pbz film. The respective films' mechanical properties were also investigated to study the film‐forming capability of the films.

Antibacterial Activity and Stability of Methanol Extract from Thamnolia subuliformis in Vitro

The objective of the study was preliminarily explore the antibacterial activity and stability of Thamnolia subuliformis in vitro, the plate drilling method was used to determine the antibacterial activity of methanol extract of Thamnolia subuliformis against common pathogenic bacteria in vitro. The indicator bacteria of Staphylococcus aureus was used to determine the effects of factors such as different temperature, pH and UV irradiation time on antibacterial stability. Petroleum ether, ethyl acetate and n-butanol were used to extract the methanol extract, determine the polarity of its antibacterial active substances, and determine the content of usnic acid. The results showed that the methanol extract of Thamnolia subuliformis had good antibacterial effect on Gram-positive bacteria such as Staphylococcus aureus, Bacillus subtilis, Listeria stephensi, Staphylococcus surface, Listeria evansi, paratyphoid A, paratyphoid B of Gram-negative bacteria and Candida albicans. The minimum inhibitory concentration and minimum bactericidal concentration against Staphylococcus aureus were 0.625 and 10 mg/mL respectively; The results of antibacterial stability test showed that temperature had no significant effect on the antibacterial activity of methanol extract of Thamnolia subuliformis（P>0.05）, and it still had high antibacterial activity after treatment at 100 ℃ for 30 min; The antibacterial activity of UV irradiation for 40 min and 50 min decreased significantly (P 0.05）, showing high antibacterial activity. When the pH was high (8.0, 10.0) or low (2.0, 4.0), the antibacterial activity of the treatment group decreased significantly (P<0.05), and decreased with the increase or decrease of pH, The content of usnic acid in methanol extract and ethyl acetate extract of Thamnolia subuliformis was 0.8613% and 0.9379%, respectively. The results show that the methanol extract of Thamnolia subuliformis has a certain broad-spectrum antibacterial effect, low concentration and good stability. It can be used for the development and utilization of natural food preservatives and plant-derived antibacterial drugs.

Experimental Evaluation of Coffee Husk Ash as a Filler in Hot Mix Asphalt Concrete Productions

The use of coffee husk ash (CHA) as a mineral filler in hot mix asphalt was investigated in this study. Crushed stone dust (CSD) was used as the mineral filler in four distinct serial asphalt concrete samples (5.5%, 6.5%, 7.5%, and 8%) for this purpose. The samples’ ideal bitumen content and Marshall stability (MS) value were calculated. The 6.5% filler asphalt series, which has offered the most stability, was picked, and CHA was substituted for it at rates of 25%, 50%, 75%, and 100%. The produced samples were then subjected to an MS test, and the results were evaluated. The effects of mineral filler on the susceptibility of asphalt concrete to moisture were also examined in the present study along with the preparation and evaluation of Marshall stability mixtures with various CHA and bitumen levels. The maintained stability test also evaluates a bituminous mix’s capacity to be stripped. The findings indicated that for stability, flow, air voids, VFA, and bulk density, respectively, the optimum asphalt content (5.57%) and filling rate at 75% replacement of crushed stone dust with coffee husk ash had values of 16.820 kN, 4.983 mm, 4.435%, and 73.717%. CHA can be used as long as 75% of the CSD filler material complies with the minimum standards set by the Ethiopian Road Authority and global standards for the manufacturing of hot mix asphalt concrete. The retained stability (RS) test results showed that the retained stability values increased with an increase in bitumen content, indicating that the effect of moisture damage decreases with an increase in asphalt content because a high bitumen content will have a thicker content, which reduces the tendency for the water to percolate into the asphalt mix and cause moisture‐related problems.

A rapid and quantitative detection method for plasma soluble growth stimulating gene protein 2 based on time resolved fluorescence immunochromatography.

Background: plasma soluble growth stimulating gene protein 2 (sST2) is a new generation biomarker in heart failure (HF), which is an independent predictor of adverse outcomes of heart failure. Thus, the establishment of a rapid and sensitive method for detecting sST2 is urgently needed. Methods: lanthanide element Eu3+ coated fluorescent nanometer microspheres (Eu3+@FMN) can be used as markers to label monoclonal mouse anti-human sST2 antibody ST-01 (ST-01-Eu3+@FMN). When the immune sandwich complex formed between the monoclonal mouse anti-human sST2 antibody ST-02 and ST-01-Eu3+@FMN on the test band with the appearance of target object sST2, we can detect the fluorescence intensity of Eu3+ on the test band and the quality control band using a dry fluorescence analyzer. We calculated the T/C value (T/C = fluorescence intensity of the test band/fluorescence intensity of the quality control band), fitted to the calibration curve, and measured the concentration value of sST2 in the corresponding sample. Results: the best reaction time was 15 min after condition exploration, and the optimal sample volume was 80 μL. The detection sensitivity of the scheme was 2.14 ng mL-1. The calibration curve of the assay was y = 0.0113x + 0.0033, and the linear range was 5-200 ng mL-1. No cross reaction was found when the samples contained BNP, NT-proBNP, and galectin-3, indicating a good specificity. The precision was good with a relative deviation < 15%. The coefficient of variation of detection results of low-concentration samples and high-concentration samples was 4.20% and 3.30% respectively in the same batch of strip tests, so the intra-assay CV was set as <10%; when different batches of strips were used for testing, the coefficient of variation of detection results of low-concentration samples and high-concentration samples was 10.06% and 8.38% respectively, so the inter-assay CV was set as <15%. Stability test results showed that the relative deviation of test results at each time node was <15%, indicating good stability of the assay strips. The correlation coefficient between the ST-01-Eu3+@FMN based time-resolved fluorescence immunochromatography analysis and sST2 ELISA kit was 0.98. To confirm the usage of our proposed TRF-ICA for clinical samples, it was used to determine the concentration of sST2 in samples obtained from 34 patients with heart insufficiency, acute and chronic heart failure. As a result, we successfully detected a minimal concentration of 5.21 ng mL-1 and a maximum concentration of 184.26 ng mL-1 for sST2. Conclusion: this technique provides a rapid, simple and quantitative detection method for sST2 in clinics. It can help clinicians to predict the incidence of adverse events in patients with HF.

Evaluation of remelting low-fluxing ferrotitanium slag as a potential refractory raw material: Thermal characteristics and stability

To effectively promote the utilization of metallurgical waste slag, studies on the characteristics and stability of waste slag are essential for waste reuse. Ferrotitanium slag is a byproduct of smelting ferrotitanium with thermite reduction. Low-fluxing ferrotitanium slag (LFS) is the main type of dumping slags produced by ferrotitanium smelting. In this study, an electric arc furnace was used to prepare remelting LFS (RLFS) for homogenization and impurity removal. The characteristics and thermal stability of RLFS as a refractory raw material were characterized. The thermal stability of RLFS was tested under different working conditions. A phase-structure transition mechanism of RLFS particles was established according to the thermal stability test and thermodynamic calculations. The Al2O3 content in RLFS exceeded 80%, and RLFS had lower thermal conductivity than brown corundum, but a similar thermal expansion coefficient. The results show that RLFS is a suitable substitute for corundum raw material; the thermal stability test results show that RLFS was susceptible to crack propagation in an oxidizing environment above 1280 °C. The findings of this research provide suggestions for the utilization of RLFS to improve the application stability of refractory products using recycled raw materials.

Formulasi Sediaan Liniment Aromaterapi dari Minyak Atsiri Bunga Kenanga (Cananga odorata)

Cananga essential oil has potential as an antidepressant and a relaxant for the nervous system, containing a compound, namely linalool from the monoterpene. The innovation of topical pharmacy preparations with the active ingredient of cananga essential oil is a useful. The purpose of this study was to formulate cananga essential oil with concentrations used of 1%, 2% and 4%. The results showed that formulas I, II and III had met the physical quality evaluation. The results of the organoleptic test of the three formulations were in the form of a liquid, a characteristic odor of cananga flower along with eucalyptus oleum and a light yellow color. The results of the pH stability test obtained an average of 4.2 formulations, 4.9 formulations II and 5 formulations III. The homogeneity test results from formulations I, II and III obtained homogeneous results. The results of the anti-irritation test of formulations I, II and III did not cause irritation. The overall results of the preference test showed that the panelists preferred the liniment preparation at a concentration of 4%. Concluded that the formulation of liniment with the active ingredient of cananga essential oil produced preparations that met the physical characteristics and hedonic tests.

Pengaruh Pelarut, Suhu, dan pH Terhadap Pigmen Antosianin dari Ekstrak Kulit Buah Naga Merah (Hylocereus Polyrhizus)

Red dragon fruit peel (Hylocereus polyrhizus) is an agricultural waste that contains quite high natural anthocyanin pigments. The purpose of this study was to determine how the effect of solvent, temperature and pH on the total content and stability of anthocyanins from liquid extract of red dragon fruit peel. Extraction of anthocyanins from red dragon fruit peel using maceration method with solvent distilled water, distilled water: acetic acid 10% (1:6), and distilled water: citric acid 10% (1:6) and testing was carried out in the form of anthocyanin stability tests at pH 1, 2, 3, 4, 5 and temperatures 0°C, 10°C, 20°C, 30°C, 40°C, 50°C. The results obtained showed that the use of distilled water:citric acid 10% (1:6) as a solvent resulted in the highest total anthocyanin content with 18.034 mg/200 mg and the results of the anthocyanin stability test showed that it was stable at pH 1, 2, 3 and at temperatures of 10°C, 20°C, 30°C.

Stability and Volumetric Properties of Colored Asphalt Mixtures Containing Iron Oxide

The objective of this paper is find the effect of using iron oxide as a filler on the Marshall stability, flow and the volumetric properties of HMA and compared the results with conventional HMA using limestone dust. Three blends were used: coarse, mid and fine with neat bitumen (AC 40-50). One aggregate type (crushed) with two types of fillers: limestone and iron oxide III (α- ) with three different filler content 6%, 8% and 10%. The Marshall mix design was conducted on the three blends and the optimum binder content is computed for each blend. The Marshall stability test results and the volumetric properties analysis showed that increasing the iron oxide content from 6% to 10% increases the stability about 28%, 17% , 16% for the coarse , mid and fine mixtures respectively. This increment in stability of mixtures using iron oxide related to the increment in specific gravity of the mix (Gmb) by (1.3% to 1.5% about 30 to 50 kg/m3). On the other hand, the flow of mixtures is decreased about (5%) for mixes using iron oxide than the ones that used limestone as filler. The fine blend with 10% iron oxide exhibit the highest stability of 13.3 kN. While the coarse blend stability was 10 kN for the same filler type and content. Generally, the Marshall Test results of HMA using iron oxide as filler showed better resistance to plastic deformation, also produce denser HMA with higher stiffness. On the other hand, the volumetric properties analysis showed lesser values as compared with conventional mixture where the void in mineral aggregates and void filled with asphalt has decreased but within the acceptable limits.

Synthesis, characterization and performance of a novel Ni–Co/GO-TiO2 for electrooxidation of methanol and ethanol

In order to find out electrocatalysts based on non-precious metals, Ni–Co/GO-TiO2 composite with different amounts of nickel and cobalt is prepared and the impacts of TiO2 nanoparticles on GO support are highlighted. Composition, morphology and textural features of the synthesized materials are characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, N2 adsorption-desorption isotherms and field emission scanning electron microscopy equipped with energy-dispersive X-ray analysis. The electrochemical activity of the prepared catalysts toward methanol and ethanol electrooxidation in alkaline media is investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and chronoamperometry. Results confirmed that adding TiO2 nanoparticles to graphene oxide can increase the surface area, porosity and electrochemically active surface area of the support material. The composition with the equal amount of nickel and cobalt precursors exhibited the highest current density for methanol and ethanol electrooxiation equal to 121.07 and 145.28 mA/cm2, respectively. Stability test results demonstrated that this sample maintains 94.1% and 87.5% of initial current density after 7200 s for the electrooxidation of ethanol and methanol in 1.0 M KOH, respectively. All results confirm the synergic effect of Ni and Co for the alcohols oxidation in alkaline media and equal amount of Ni and Co leads to the best catalytic performance with the highest current density, lowest impedance and maximum stability.

Rheological evaluation of asphalt binder modified by amorphous poly alpha olefin (APAO)

This study examined the effect of amorphous poly alpha olefin (APAO) on the rheological behavior of asphalt binder. In order to modify asphalt binder, several percentages of APAO (0, 2, 4, 6, 8%, and 10% by the weight of asphalt binder) were used. The penetration grade, softening point, ductility, and viscosity tests were performed. Also, the multiple stress creep recovery (MSCR) and linear amplitude sweep (LAS) tests were conducted to evaluate the rutting and fatigue behavior of asphalt binder. The storage stability test was implemented to measure the ability of modified asphalt binder against separation. Based on the results, using APAO reduced the penetration grade and increased the softening point due, maybe, to the asphalt binder stiffening. The PI values increased with the addition of APAO, which indicated that the temperature susceptibility of all modified asphalt samples was reduced compared to the base asphalt binder. The increase in the viscosity of virgin asphalt binder due to APAO addition caused the mixture placement/compaction operations to become harder. The G*/sinδ parameter for all types of pre-post-aging RTFO asphalt binders was improved for APAO-modified asphalt binder, meaning that the latter stiffened and thus increased the respective rutting resistance of mixtures. The low-temperature performance of asphalt binder indicated that the stiffness of asphalt sample increased with an increase in the APAO percentage, which indicates that the addition of APAO improved the cracking potential of modified asphalt binders and had negative effects on the asphalt binders. The storage stability test results indicated that the phase separation of asphalt binder was related to the APAO content. Results revealed, ignoring the levels of stress, that using APAO reduced the non-recoverable creep compliance (Jnr) value of virgin asphalt binder, indicating the production of an asphalt binder benefitting higher rutting resistance with APAO modification. APAO increased the %R of asphalt binder. Based on the LAS test results, the addition of APAO led to an increase in the fatigue life of asphalt binders, and by increasing the additive content, the fatigue life increased. The FTIR analysis indicated that no chemical interaction was observed between asphalt binder and APAO.

2D material assisted SMF-MCF-MMF-SMF based LSPR sensor for creatinine detection.

The purpose of this work is to propose a simple, portable, and sensitive biosensor structure based on singlemode fiber-multicore fiber-multimode fiber-singlemode fiber (SMF-MCF-MMF-SMF) for the detection of creatinine in the human body. Chemical etching has been used to modify the diameter of the sensing probe to approximately 90 μm in order to generate strong evanescent waves (EWs). The sensor probe is functionalized with graphene oxide (GO), gold nanoparticles (AuNPs), molybdenum disulfide nanoparticles (MoS2-NPs), and creatininase (CA) enzyme. The concentration of creatinine is determined using fiber optic localized surface plasmon resonance (LSPR). While EWs are used to enhance the LSPR effect of AuNPs, two-dimensional (2D) materials (GO and MoS2-NPs) are used to increase biocompatibility, and CA is used to increase probe specificity. Additionally, HR-TEM and UV-visible spectroscopy are used to characterize and measure the nanoparticle (NP) morphology and absorption spectrum, respectively. SEM is used to characterize the NPs immobilized on the surface of the fiber probe. The sensor probe's reusability, reproducibility, stability, selectivity, and pH test results are also tested to verify the sensor performance. The sensitivity of proposed sensor is 0.0025 nm/μM, has a standard deviation of 0.107, and has a limit of detection of 128.4 μM over a linear detection range of 0 - 2000 μM.

PHYSICAL STABILITY TEST AND ETHANOL CREAM IRRITATION TEST OF Moringa oleifera L.

The development of topical dosage forms of Moringa leaf extract cream has been carried out because of its properties that can moisturize the skin. A pharamceutical preparation must meet the requirements of stability and non toxic. The study aimed to determine the effect of variations un the concentration ethanol extract cream of Moringa leaf of physical stability and irritability. Ethanol extract of Moringa leaves was obtained by maceration method with 50% ethanol solvent. The extract was then formulated in the form of O/W base scarring with concentrations of 1% (F1), 3% (F2), and 5% (F3). Creams were evaluated for physical stability including mechanical tests (centrifugation) and physical stability at room temperature (25 ± 2oC) with parameters pH, viscosity on days 1, 7, 14, 21 and 28. In addition, creams were also evaluated for their irritability in vivo with using test animals (rabbits). The data obtained were analyzed using one-way ANOVA test. The results of the physical stability test showed that an increase in the concentration of Moringa leaf extract caused an increase in viscosity (P &lt;0.5) and a decrease in pH (P &lt;0.5) but did not affect physical stability (mechanical test) and its irritating effect. F2 (1%) has a pH of 7.61 while F4 (5%) is 7.01. Based on the results of the study, it is concluded that variations in the concentration of ethanol extract of Moringa leaves can affect the physical stability of the cream and do not affect its irritation properties. Moringa leaf ethanol extract cream with a concentration of 5% (F4) has physical stability and does not irritate the skin better than other formulas.

Well-Dispersed MgAl2O4 Supported Ni Catalyst with Enhanced Catalytic Performance and the Reason of Its Deactivation for Long-Term Dry Methanation Reaction

Dry methanation of syngas is a promising route for synthetic natural gas production because of its water and cost saving characteristics, as we reported previously. Here, we report a simple soaking process for the preparation of well-dispersed Ni/MgAl2O4-E catalyst with an average Ni size of 6.4 nm. The catalytic test results showed that the Ni/MgAl2O4-E catalyst exhibited considerably higher activity and better stability than Ni/MgAl2O4-W catalyst prepared by conventional incipient wetness impregnation method in dry methanation reaction. The long-term stability test result of 335 h has demonstrated that the deactivation of the Ni/MgAl2O4-E catalyst is inevitable. With multiple characterization techniques including ICP, EDS, XRD, STEM, TEM, SEM and TG, we reveal that the graphitic carbon encapsulating Ni nanoparticles are the major reasons responsible for catalyst deactivation, and the rate of carbon deposition decreases with reaction time.

Revealing the genuine stability of the reference Pt/C electrocatalyst toward the ORR

Stability is an essential metric of electrocatalysts, but the reported experimental results are often flawed, indicated by the highly inconsistent stability data of the reference catalysts seen in the literature. In this work, focusing on the Pt/C reference catalyst toward the oxygen reduction reaction, we attempted to clarify its genuine stability under the most used accelerated stress test conditions and understand the reasons for the flawed results. Efforts have been made to design an electrochemical cell and an extended test protocol to control all possible experimental factors that could influence the test results. We found that simple experimental errors such as incomplete catalyst activation and accumulated electrolyte impurities could significantly affect the stability test results. Under strictly controlled conditions, a reliable stability benchmark of Pt/C catalyst toward the oxygen reduction reaction has been established. The proposed experimental procedure could serve as a general reference for determining the stability of electrocatalysts for different electrochemical systems.

Prevalence and Characteristic of Swine-Origin mcr-1-Positive Escherichia coli in Northeastern China.

The emergence of the plasmid-mediated colistin resistance gene mcr-1 is threatening the last-line role of colistin in human medicine. With mcr-1-positive Escherichia coli (E. coli) isolated from food animal being frequently reported in China, the prevalence of mcr-1 in food animal has attracted public attention. In the present study, a total of 105 colistin-resistant E. coli strains were isolated from 200 fecal samples collected from six swine farms in northeastern China. mcr-PCR revealed that the prevalence of mcr-1 in colistin-resistant E. coli was 53.33% (56/105). mcr-1-positive E. coli showed extensive antimicrobial resistance profiles with the presence of additional resistance genes, increased expression of multidrug efflux pump-associated genes, and increased biofilm formation ability. MLST differentiated all the mcr-1-positive E. coli into 25 sequence types (STs) and five unknown ST, and the most common ST was ST10 (n = 11). By phylogenetic group classification, the distribution of all mcr-1-positive E. coli belonging to groups A, B1, B2, and D was 46.43, 35.71, 5.36, and 5.36%, respectively. Conjugation experiment demonstrated that most of the mcr-1 were transferable at frequencies of 2.68 × 10–6–3.73 × 10–3 among 30 representative mcr-1-positive E. coli. The plasmid replicon types IncI2 (n = 9), IncX4 (n = 5), IncHI2 (n = 3), IncN (n = 3), and IncP (n = 1) were detected in the transconjugants. The results of growth assay, competition experiment, and plasmid stability testing showed that acquisition of mcr-1-harboring plasmids could reduce the fitness of bacterial hosts, but mcr-1 remained stable in the recipient strain. Due to the potential possibility of these mcr-1-positive E. coli being transmitted to humans through the food chain or through horizontal transmission, therefore, it is necessary to continuously monitor the prevalence and dissemination of mcr-1 in food animal, particularly in swine.

Uji Efek Antioksidan Formulasi Sediaan Sirup Ekstrak Etanol Kulit Buah Jeruk Bali (Citrus Maxima Merr.) Terhadap Malondialdehid Tikus Putih (Rattus Novergicus) Yang Diinduksi Karbon Tetraklorida

Free radicals are any molecule or atom that is unstable because it has one or more unpaired electrons. Free radicals that are formed in the body will produce new free radicals through a chain reaction which eventually increases in number and attacks the body's cells so that tissue damage will occur, therefore antioxidants are needed from outside to neutralize free radicals, the salute is grapefruit peel (Citrus maxima Merr.) This study aims to determine the antioxidant activity of the ethanol extract syrup of grapefruit peel against levels of Malondialdehyde (MDA) blood plasma of male white rats induced by carbon tetrachloride (CCl4). The stages of this study were the first to make a skin extract syrup. grapefruit peel containing 1% extract (F1), 2% extract (F2), 3% extract (F3), and without grapefruit peel extract (F4) as negative control; Furthermore, testing the stability of the syrup preparations before and after storage was accelerated for 12 cycles, and finally the syrup with the best stability was tested for its lipid peroxidation inhibition activity in vivo with blood plasma MDA levels in rats induced by Carbon Tetrachloride. The results showed the results of the syrup stability test. indicates that F3 has the best stability. As for the in vivo test results, F3 showed a decrease in the MDA level of blood plasma in rats which was significantly different from the negative control. The grapefruit peel significantly decreased the MDA level of the rat blood plasma with a value p&lt;0.05. Keywords : Free radicals, Grapefruit Peel, Antioxidant, Syrup Preparation, Malondialdehyde (MDA)

FeCo66.7Ni33.3B Nanoparticles Integrated on Vertically Aligned Boron-Doped Graphene Array as Efficient Electrocatalyst for Overall Water Splitting in Wide pH Range

FeCoxNiyB nanoparticles with tuned cationic ratio integrated on Vertically Aligned Boron-doped Graphene Array (FeCoxNiyB@B-VG) electrocatalysts towards water splitting are successfully prepared by electroless plating. For a specific composition, FeCo66.7Ni33.3B@B-VG electrocatalyst exhibits the highest electrocatalytic activity towards hydrogen evolution reaction, with low overpotentials of 125 and 157 mV at η 10 and small Tafel slopes of 52 and 47 mV dec−1 in 1.0 M KOH and 0.5 M H2SO4 solution, respectively. FeCo66.7Ni33.3B@B-VG electrocatalyst displays remarkable catalytic activity towards oxygen evolution reaction by showing low overpotentials of 200 and 569 mV at η 10 and small Tafel slopes of 34 and 225 mV dec−1 in 1.0 M KOH and 0.5 M H2SO4 solution, respectively. The result of stability test exhibits that FeCo66.7Ni33.3B@B-VG electrocatalyst has long-term stability for at least 10 h towards water splitting in a wide pH range. And the faraday efficiency of FeCo66.7Ni33.3B@B-VG towards water splitting is around 90%. This study helps to explore the effect of variable cationic ratio in the fabrication of non-noble electrocatalyst to achieve enhanced electrocatalytic activity for water splitting in a wide pH range.

A novel technology to reduce astringency of tea polyphenols extract and its mechanism

ObjectiveTea polyphenols are natural extracts used widely throughout the world. However, the severe astringency of tea polyphenols has reduced patient compliance. Based on the analysis of the formation mechanism of astringency, this paper hopes to propose a new method to control the astringency of tea polyphenols and improve patient compliance without changing its effect. MethodsArtificial saliva was used to prepare the tea polyphenols solution with different pH, using β-casein to imitate salivary protein, and preparing 1.2 mg/mL β-casein solution. A fluorescence quenching test was used to study the interaction between tea polyphenols and β-casein, combined with the stability test results of the compound, we can choose the pH with weak binding but good stability as the best pH for masking astringency. The taste-masking tablets were prepared under the best pH conditions, and the Xinnaojian Original Tablets were prepared according to the conventional preparation method. The disintegration time limit and solubility were tested respectively. The astringency of Xinnaojian original tablets and taste-masking tablets was evaluated by visual analogue scale (VAS). ResultsThe result of the fluorescence quenching test prompted that the combination force was the weakest when the pH was 4.9. Further synchronous fluorescence analysis showed that an increase in pH resulted in a decrease of the binding sites between tea polyphenols and β-casein, and this decrease was closely related to changes in tryptophan residues in β-casein. Both original and taste-masking Xinnaojian Tablets were prepared. Volunteers’ VAS scores illustrated that the astringency improved significantly with the masking tablets (P < 0.05). ConclusionThis pH-adjusting masking treatment had little effect on the recovery of polyphenols from the tablets or the dissolution of the tablets. This study provides a novel and feasible astringency masking technology for tea polyphenols and its preparation.