The combined effects of ultrasound and lactic acid in inactivating microorganisms on fresh radish (Raphanus raphanistrum subsp. sativus) : microbiological and quality changes

In order to reduce the risk of microbial contamination in fresh radish (Raphanus raphanistrum) and ensure its safety, combined effects of ultrasound and lactic acid in inactivating microorganisms and quality changes of radish were studied. Fresh radish samples were inoculated with Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and Shigella sonnei separately and were treated with lactic acid (L) 1% and 2%, ultrasound (U) with the amplitude of 0%, 25%, 50%, and 75% for 15 and 30 min and their combination. The quality parameters, including total phenol content, firmness, and total color change, were evaluated on the day of the experiment and after 24 hr of cold storage. Results showed that both applied treatments and their combinations had significant (p < .05) inhibitory effect on all of the studied bacteria. Total phenolic content of the ultrasound treated samples led to higher amounts comparing to other samples. Results showed that using ultrasound power (75%), for 30 min significantly (p < .05) decreased the firmness of samples after 24 hr of cold storage. In conclusion, the application of ultrasound and lactic acid can extend the shelf life of fresh radish8116216

Extensions of rings over 2-primal rings

‎For a set of endomorphisms $\Sigma‎ :‎= \{\sigma _1,\ldots‎ , ‎\sigma _n\}$ and derivations $\Delta‎ :‎= \{\delta _1,\ldots‎ , ‎\delta _n\}$‎, ‎we first introduce $\Sigma$-compatible ideals which are a generalization of $\Sigma$-rigid ideals and study the connections of the prime radical and the upper nil radical of $R$ with the prime radical and the upper nil radical of the skew PBW extension‎. ‎Let $A = R \left\langle x_1‎, ‎\ldots‎ , ‎x_n; \Sigma‎, ‎\Delta‎ ‎\right\rangle$ be an injective skew PBW extension of an‎ ‎$(\Sigma,\Delta)$-compatible ring $R$‎. ‎(i) It is shown that if‎ ‎$R$ is a (semi)prime ring‎, ‎then $A$ is a (semi)prime ring‎. ‎(ii)‎ ‎If $R$ is a completely (semi)prime ring‎, ‎then $A$ is a‎ ‎completely (semi)prime ring‎. ‎(iii) If $R$ is a strongly‎ ‎(semi)prime ring‎, ‎then $A$ is a strongly (semi)prime ring‎. ‎Also‎, ‎we prove that $R$ is $2$-primal if and only if the‎ ‎injective skew PBW extension $A$ is $2$-primal if and only if‎ ‎$nil(R) = nil_{*}(R; \Sigma \cup \Delta)$ if and only if $‎ ‎nil(R)\left\langle x_1‎, ‎\ldots‎ , ‎x_n; \Sigma,\Delta\right\rangle‎ ‎= nil_*(A)$ if and only if every minimal $(\Sigma,\Delta)$-prime‎ ‎ideal of $R$ is completely prime‎

A Comparison of Bacteriological Culture, Serology, and Quantitative PCR for Detecting Brucellosis in Ewes with a History of Abortion

The zoonotic disease brucellosis is a serious public health and livestock industry concern. In the present study, we used bacteriological culture, RBT, and qPCR to determine the prevalence of brucellosis in the serum and milk samples of sheep with a history of abortion. Serum and milk samples were obtained from 100 sheep aged 3-5 years. In order to determine the prevalence of brucellosis, a modified RBT was performed on serum samples, Brucella was isolated from milk by bacteriological culture, and qPCR was applied to detect bacterial DNA in milk. The prevalence of brucellosis using modified RBT, bacteriological culture, and qPCR was 32%, 42%, and 44%, respectively. By considering qPCR as the standard, modified RBT showed a sensitivity of 95%, a specificity of 100%, an accuracy of 98%, a PV+ of 100%, and a PV- of 97%. The sensitivity, specificity, accuracy, PV+, and PV- for bacteriological culture were 77%, 100%, 90%, 100%, and 85%, respectively. The agreement between qPCR and modified RBT was 0.959 (95% CI: 0.896-1), between qPCR and bacteriological culture was 0.792 (95% CI: 0.667-0.897), and between modified RBT and bacteriological culture was 0.831 (95% CI: 0.709-0.38). Based on the results, bacterial isolation from sheep milk is not recommended except in specific cases due to its low sensitivity, as well as its time-consuming and hazardous nature. However, the modified RBT can be used as a routine method because of its cost-effectiveness, higher sensitivity, and higher accuracy compared to bacterial isolation. Moreover, qPCR is recommended as the gold standard test for detecting brucellosis in sheep milk, especially in those with a history of abortion

Generalization in the learning of mathematics

Generalization is one of the fundamental activities in the learning of mathematics. The growing and improving mathematics is depended to applications of generalization from beginning until now. It seems that generalization needs to be introduced more among people who deal with mathematics. The main aim of this conceptual study is to explore the meanings of generalization from psychological and mathematical perspectives. In addition, the importance of generalization to support students in the learning of mathematical concepts is put forward

Undergraduate students' difficulties in conceptual understanding of derivation

Derivation is one of the fundamental concepts in the learning of university mathematics. It is a prerequisite for other concepts in undergraduate level and its traces are visible in the majority of mathematical courses at university level. Students have difficulties in the learning of this concept which mostly come back to lack of conceptual understanding. The purpose of this study is to investigate the reasons of difficulties, which faced students in conceptual understanding of derivation. The design of this study is qualitative analysis of open-ended questions, and its subjects consisted of 63 undergraduate students. The findings showed students have serious difficulties in understanding conceptually of derivation. The students’ responds indicated that main reasons of difficulties in conceptual understanding of derivation come back to focusing on symbolic aspect more than embodied aspect, lack of making logical connection between these aspects, and weakness of dealing with generalized question. Findings of this study provide information to undergraduate instructors and students to overcome learning difficulties of derivation

Evaluating polyethyleneimine/DNA nanoparticles-mediated damage to cellular organelles using endoplasmic reticulum stress profile

Gene therapy has emerged as an influential tool for treating the genetic and specific acquired disorders. Among all kinds of gene delivery systems, the cationic polymer polyethyleneimine (PEI) is considered as a promising non-viral gene delivery vector, although there are still concerns about its magnitude of cytotoxicity. While any cell insult leads to unfolded/misfolded protein accumulation and its consequent unfold protein response, evaluating the expression profile of ER-stress genes would be a sensitive indicator of cell stress. Beside cytotoxicity assays, real-time RT-PCR was used to investigate the effects of PEI nanoparticles on the endoplasmic reticulum. Treating Neuro2A cells revealed that PEI can induce cell toxicity in a concentration-dependent manner. Also, It increased the transcript levels of Grp78 (Bip), Atf4 and Chop, and splicing of Xbp1. To further optimize the transfection properties in Neuro2A cells, PEI was used to deliver a plasmid DNA containing GFP reporter. While different PEI/plasmid ratios revealed similar transfection efficiency, increasing the PEI/plasmid ratio led to induction of ER-stress markers. These results underscored that beside the effectiveness of PEI, using the lowest possible ratio of PEI/plasmid would minimize the detrimental effects of PEI on cells and confer it a beneficial therapeutic importance in nucleic acid delivery

Designing Learning Strategy to Improve Undergraduate Students' Problem Solving in Derivatives and Integrals: A Conceptual Framework

Derivatives and integrals are two important concepts of calculus which are precondition topics for most of mathematics courses and other courses in different fields of studies. A majority of students at the undergraduate level have to master derivatives and integrals if they want to be successful in their studies However, students encounter difficulties in the learning of derivatives and integrals. Most of these difficulties arise from the students' weakness in problem solving. This paper presents a learning strategy which has been designed to overcome these difficulties based on mathematical thinking and generalization strategies with prompts and questions

Antiproliferative and Apoptotic Effects of Graphene Oxide @AlFu MOF Based Saponin Natural Product on OSCC Line

The increasing rate of oral squamous cell carcinoma (OSCC) and the undesirable side effects of anticancer agents have enhanced the demand for the development of efficient, detectable, and targeted anticancer systems. Saponins are a diverse family of natural glycosides that have recently been evaluated as an effective compound for the targeted therapy of squamous cell carcinoma. Due to their porous nature and stable structure, metal–organic frameworks (MOFs) are a well-known substance form for various biological applications, such as drug delivery. In this study, we fabricated a novel hybrid, highly porous and low-toxic saponin-loaded nanostructure by modifying graphene oxide (GO)/reduced GO (rGO) with aluminum fumarate (AlFu) as MOF core–shell nanocomposite. The characterization of the nanostructures was investigated by FTIR, TEM, EDX, FESEM, and BET. MTT assay was used to investigate the anticancer activity of these compounds on OSCC and PDL normal dental cells. The effect of the nanocomposites on OSCC was then investigated by studying apoptosis and necrosis using flow cytometry. The GO/rGO was decorated with a saponin–AlFu mixture to further investigate cytotoxicity. The results of the MTT assay showed that PDL cells treated with AlFu–GO–saponin at a concentration of 250 μg/mL had a viability of 74.46 ± 16.02%, while OSCC cells treated with this sample at a similar concentration had a viability of only 38.35 ± 19.9%. The anticancer effect of this nanostructure on OSCC was clearly demonstrated. Moreover, the number of apoptotic cells in the AlFu–GO–saponin and AlFu–rGO–saponin groups was 10.98 ± 2.36%–26.90 ± 3.24% and 15.9 ± 4.08%–29.88 ± 0.41%, respectively, compared with 2.52 ± 0.78%–1.31 ± 0.62% in the untreated group. This significant increase in apoptotic effect observed with AlFu–rGO–saponin was also reflected in the significant anticancer effect of saponin-loaded nanostructures. Therefore, this study suggests that an effective saponin delivery system protocol for the precise design and fabrication of anticancer nanostructures for OSCC therapy should be performed prior to in vivo evaluations