Broad distribution of enterotoxin genes (hblCDA, nheABC, cytK, and entFM) among Bacillus thuringiensis and Bacillus cereus as shown by novel primers

Eight new pairs of PCR primers were designed and efficiently detect eight toxin genes (hblC, hblD, hblA, nheA, nheB, nheC, cytK, and entFM) in 411 B. cereus strains (121 food- and 290 soil isolates) and 205 B. thuringiensis strains (43 serovars, 10 food- and 152 soil isolates). According to the presence of these eight toxin genes, they were divided into four groups among the total 616 isolates. In Group I, all eight genes occurred simultaneously in 403 (65.42%) isolates, while Group II (134 isolates or 21.75%) and Group III (46 isolates or 7.47%) were devoid of hblCDA and cytK, respectively. In Group IV, there were thirty-three isolates which lacked both hblCDA and cytK. The presence of hblCDA in B. thuringiensis strains (86.80%) was significantly higher (P<0.05) than in B. cereus strains (66.18%) whereas no significant difference in nheABC, cytK and entFM occurrence was detected between both bacterial groups. Both nheABC and entFM genes were found in all B. cereus and B. thuringiensis strains (616 strains in total), while the cytK gene could be detected in 365 (88.80%) of the B. cereus and 172 (83.90%) of the B. thuringiensis strains. None of the 616 tested strains showed the presence of only a single or two genes in either the hbl or nhe operons. The eight primer pairs designed for this multiplex PCR allowed rapid detection of eight toxin genes from boiled cells with high sensitivity, gave 100% reproducibility, and did not cross-react to 32 other bacterial strains.     

Optimization of Channel Estimation Using ELMx-based in Massive MIMO

In communication channel estimation, the Least Square (LS) technique has long been a widely accepted and commonly used principle. This is because the simple calculation method is compared with other channel estimation methods. The Minimum Mean Squares Error (MMSE), which is developed later, is devised as the next step because the goal is to reduce the error rate in the communication system from the conventional LS technique which still has a higher error rate. These channel estimations are very important to modern communication systems, especially massive MIMO. Evaluating the massive MIMO channel is one of the most researched and debated topics today. This is essential in technology to overcome traditional performance barriers. The better the channel estimation, the more accurate it is. This paper investigated machine learning (ML) for channel estimation. ML channel estimations based on the Extreme Learning Machine (ELMx) group are also implemented. These estimations, known as the ELMx group, include Regularized Extreme Learning Machine (RELM) and Outlier Robust Extreme Learning Machine (ORELM). Then, it was compared with LS and MMSE. The simulation results reveal that the ELMx group outperforms LS and MMSE in channel capacity and bit error rate. Additionally, this paper has proven complexity for verified computational times. The RELM method is less time consuming and has low complexity which is suitable for future use in large MIMO systems.     

Modified cassava starch/poly(vinyl alcohol) blend films plasticized by glycerol: Structure and properties

We report a systematic investigation on the structure–property relationships in glycerol-plasticized poly(vinyl alcohol) (PVA)/cassava starch blends prepared via solution casting. In particular, PVA mixed with native, low-oxidized, high-oxidized, and pregelatinized cassava starches were characterized by means of SEM, XRD, FTIR, thermal analysis and mechanical testing and the immiscible systems were received. Burial tests over a period of several days suggested the preferential degradation of the starch and glycerol component (as indicated by the absence of FTIR signatures of those components) and the amorphous phase of PVA (as indicated by the enhanced crystallinity index of the degraded samples). The rheological properties of the blends seem to dictate their morphological characteristics that, in turn, have a profound impact on their mechanical properties. In that sense, the study highlights promising strategies for the development of a new family of polymeric materials that combine their biodegradable nature within superior mechanical properties. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48848.     

浅谈余秋雨散文中的“两难”构思

从余秋雨散文集《文化苦旅》中主要的4个方面:寄情于山水名胜,对中国古代文化的追怀和反思;对文化专制的反思和对健全人格、文化良知的讴歌;对城市文明兴衰与发展的思考;对漂泊者的精神世界的探寻;对余秋雨散文中的两难构思进行了分析,认为两难构思作为文化散文的一种催化剂,可以触发读者的遐想和讨论,从而吸引读者,使作者与读者之间建立更自然、更深入的交流,在散文中的作用举足轻重。     

Correlating the Speed of Sound with the Gibbs Energy and Estimating the Speed of Sound in Fatty Acid Methyl Ester and Biodiesel

The relationship between the speed of sound (u) in biodiesel and the change in Gibbs energy (ΔG) has not been described in the literature. With the Gibbs energy additivity method, the relationship between u and ΔG can be expressed as ln(u²) = ΔG/RT + A, where R is the universal gas constant, T is the absolute temperature, and A is a constant. The molecule of fatty acid methyl ester (FAME) was arbitrarily sub-divided into groups of atoms and a ΔG was assigned to each group of atoms. A new model correlating the speed of sound to the structure of fatty acid was derived. The proposed model was good for estimation of the speed of sound in both FAME and biodiesel at various temperatures with good accuracy. The absolute average deviations for the speed of sound in FAME (65 data points) and in biodiesel (175 data points) were 0.23% and 0.36%, respectively. Only the number of double bonds and carbon atoms of the fatty acid are required for the calculation.     

Ohmic cooking of instant rice cake soup: energy efficiency and textural qualities

Food Science and Biotechnology - The potential of ohmic heating was investigated to cook instant rice cakes according to electric field strengths (9, 12, 15, 18&nbsp;V/cm) and cooking times...     

Development of tunable biodegradable polyhydroxyalkanoates microspheres for controlled delivery of tetracycline for treating periodontal disease

This article was aimed at preparation and characterization of drug delivery carriers made from biodegradable polyhydroxyalkanoates (PHAs) for slow release of tetracycline (TC) for periodontal treatment. Four PHA variants; polyhydroxybutyrate (PHB), poly(hydroxybutyrate‐co‐hydroxyvalerate) with 5, 12, and 50% hydroxyvalerate were used to formulate TC‐loaded PHA microspheres by double emulsion‐solvent evaporation method. We also compared the effect of different molecular weight (M_w) of polyvinyl alcohol (PVA) acting as surface stabilizer on particle size, drug loading, encapsulation efficiency, and drug release profile. The TC‐loaded PHA microspheres exhibited microscale and nanoscale spherical morphology under scanning electron microscopy. Among formulations, TC‐loaded PHB:low M_w PVA demonstrated the highest TC loading with slow release behavior. Our results showed that the release rate from PHA microspheres was influenced by both the type of PHA and M_w of PVA stabilizer. Lastly, TC‐loaded PHB microspheres showed efficient killing activity against periodontitis‐causing bacteria, suggesting its potential application for treating periodontal disease. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44128.     

Optical and photocatalytic properties of La-doped ZnO nanoparticles prepared via precipitation and mechanical milling method

The synthetic method used for preparing ZnO nanoparticles strongly influenced the products obtained. The ZnO powders incorporated more La when prepared by the mechanical milling method whereas the La₂O₃/ZnO composite nanoparticles were formed better using the precipitation method. The phase formations were detected by the X-ray diffraction technique and the morphology of the samples was followed by scanning electron microscopy. The La contents affected the crystallite size. This was explained by the formation of LaOZn on the surface of the samples and by the Zener pinning effect. The band gap energy of the samples was influenced by repulsion between the valence and conduction bands and the presence of a secondary phase. The photocatalytic degradation of a methylene blue solution by the samples depended upon the number of oxygen vacancies.