87 research outputs found

    First Reusable Catalyst for the Reductive Coupling Reaction of Organohalides with Aldehydes

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    In this study, we simulate the reductive coupling (Barbier–Grignard-type) reaction of organohalides with aldehydes using a new reusable catalyst. In this regard, bimetallic alloys of NiCo encapsulated in melamine-based dendrimers (MBD) immobilized on magnetic nanoparticles symbolized as γ-Fe2O3-MBD/NiCo were designed and synthesized. The structure and properties of the catalyst were studied by a variety of techniques such as Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), energy-dispersive spectrometry (EDS) mapping, and inductively coupled plasma (ICP). The presence of NiCo nanoalloys was confirmed by XRD and XPS analysis, TEM images, and EDS mapping. Various secondary alcohols were produced in good to high yields by reductive coupling of different types of aldehydes and organohalides in the presence of HCO2K as a nonmetallic reducing agent in aqueous media catalyzed by γ-Fe2O3-MBD/NiCo. In these reactions, the high catalytic performance of γ-Fe2O3-MBD/NiCo was achieved in comparison to monometallic counterparts due to the synergistic cooperative effect of Co and Ni in the NiCo nanoalloys. Magnetic and hydrophilic properties of the catalyst facilitate the catalyst recyclability for seven runs. The reusability of γ-Fe2O3-MBD/NiCo, use of water as an environmentally friendly solvent, ease of processing, and absence of metal additives make this process an excellent choice for the reductive coupling reaction to produce secondary alcohols from aldehydes. This is the first report on these kinds of reactions using a reusable catalyst.Financial support for this project was acknowledged by the Birjand University Research Council

    Studying the Recent Improvements in Holograms for Three-Dimensional Display

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    Displayers tend to become three-dimensional. The most advantage of holographic 3D displays is the possibility to observe 3D images without using glasses. The quality of created images by this method has surprised everyone. In this paper, the experimental steps of making a transmission hologram have been mentioned. In what follows, current advances of this science-art will be discussed. The aim of this paper is to study the recent improvements in creating three-dimensional images and videos by means of holographic techniques. In the last section we discuss the potentials of holography to be applied in future

    A Study on Advances in Creating 3D Holographic Images and Optical Applications of Holography

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    Nowadays, the most beautiful 3D pictures and movies are created by means of holograms. The most advantage of this technique is the possibility to observe 3D images without using glasses. The quality of created images by this method has surprised everyone. In this paper, the experimental steps of making a transmission hologram have been mentioned. In what follows, current advances of this science–art will be discussed. In another section of this paper the optical application of holography has been reviewed. Finally, the predictions for the future of holography have also been studied

    A comparative study of genotoxicity and oxidative stress before and after using lemon balm and cinnamon in subjects exposed to Nickel Welding Fumes

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         By producing reactive oxygen and nitrogen species, metal-induced toxicity and carcinogenicity alter DNA bases, increase  lipid peroxidation, and change calcium and sulfhydryl homeostasis. The purpose of the study was to investigate putative effects of Lemon balm and Cinnamomum zeylanicum on the blood markers of welding workers. We measured nickel and chromium levels, biochemical parameters, blood oxidative stress markers, total antioxidant capacity (TAC), Myeloperoxidase (MPO), lipid peroxidation (LPO), and DNA damage. The study was conducted on 55 male workers who worked in an industrial subjects exposed to Nickel Welding Fumes. The participants were administered Lemon balm and Cinnamon extract infusion 1.5 (0.12 extract) and 0.25(0.013 extract) g/100 mL, respectively, they have drunken twice a day for 30 days at 7:00 AM and 2:00 PM every day. In order to analyze the achieved data, paired t-test and Pearson correlation coefficient have been used. After using the extract infusion, a significant increase revealed in TAC (p= 0.007). Also, administration of infusion decreased DNA damage but it was not statistically significant. After administration of infusion, a decrease in LPO and MPO were observed (p= 0.014, p=0.000 respectively). Also there is positive correlation between ALP and Ni with 8-oH-dG and also, between Ni and TAC. The results indicate that using infusion causes to raise in a TAC and reduce in DNA damage

    The probability of influence of the abscopal effect on reduction of similar far away 4T1 cell line tumors by irradiation of main tumor

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    The most important problem with radiotherapy is the limitation of whole body irradiation of a metastatic patient. There are evidence showing that similar effect will occur in non-irradiated tumors similar to the irradiated ones. This effect is called abscopal effect. In the present study, the abscopal effect on local induced mice breast cancers has been investigated. One million of 4T1 mice breast cancer cell line was injected to balb/c mice subcutaneously while being under anesthesia. After the growth of tumors till becoming palpable, one of two induced tumors were exposed to total 28 Gy, with gamma rays emitted from a cobalt -60 tele-therapy machine in 14 fractions with 2 Gy daily doses. Tumor volumes were measured, using the caliper. The data was analyzed by the use of non-parametrical and ANOVA tests. Similar growth in non-irradiated control tumors was seen. After 10 or 11 fractions of one- side irradiation and total dose of 20 to 22 Gy, however, non-irradiated tumors, similar to irradiated ones, showed similar effect, reduction of size and volume different from control groups (P<0.05).The reduction of non-irradiated tumors relative to irradiation of another tumor in the same mouse is the emblem of occurrence of the abscopal effect. The mechanism of the abscopal effect is unknown but it could be related to the release of cytokines from irradiated tumors with their receptors existing on the surface of non-irradiated tumors. By induction of this effect, the remission probability of small metastases after local irradiation could be possible

    Agreement Between Swept-source Optical Coherence Tomography and Rotating Scheimpflug Camera in Measurement of Corneal Parameters in Normal and Keratoconic Eyes

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    Purpose: This study aimed to assess the agreement between topographic indices of healthy subjects and keratoconus (KCN) patients using a swept-source optical coherence tomography (SS-OCT CASIA2) versus a Scheimpflug camera (Pentacam). Methods: 40 eyes of 23 patients with KCN and 40 eyes of 20 healthy subjects were included and evaluated with the CASIA2, followed by the Pentacam. Two consecutive modalities were obtained for one eye of each patient. Corneal parameters, including anterior keratometry at steep (Ks) and flat meridians (Kf), anterior astigmatism, anterior and posterior corneal elevation values, thinnest corneal thickness, and apex corneal thickness, were evaluated. Results: CASIA2 and Pentacam showed perfect agreement (95% limits of agreement (LoA): -0.22 to 0.68, 95% LoA: -1.5 to 1.44 D) and good correlation (Intraclass correlation (ICC):0.986, ICC:0.987; to 0.68, 95% LoA: -1.5 to 1.44 D) and good correlation (Intraclass correlation (ICC):0.986, ICC:0.987; P <0.01) for anterior (Ks) in normal and ectatic corneas, respectively. The cylinder amount had moderate agreement and correlation (95% LoA: -0.55 to 0.47D, ICC: 0.797, P <0.01) in normal, and moderate to strong agreement and correlation (95% LoA: -1.57 to 0.87D, ICC=0.911, P <0.01) in Keratoconic eyes. There was a fair agreement for anterior and posterior corneal elevation values in normal subjects (95% LoA: -3.09 to 4.59, 95% LoA: -6.91 to 7.31D). The thinnest corneal thickness amount had an excellent agreement in normal and KCN patients (ICC: 0.983, 0.953; respectively). Conclusions: Although the devices had different mean indices values, they had a good agreement based on the Bland–Altman plots. Since Pentacam is accepted as the standard tool for diagnosing ectatic cornea, pentacam CASIA2 is also helpful for early diagnosis of KCN

    Linked Fault Analysis

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    Numerous fault models have been developed, each with distinct characteristics and effects. These models should be evaluated in light of their costs, repeatability, and practicability. Moreover, there must be effective ways to use the injected fault to retrieve the secret key, especially if there are some countermeasures in the implementation. In this paper, we introduce a new fault analysis technique called ``linked fault analysis\u27\u27 (LFA), which can be viewed as a more powerful version of well-known fault attacks against implementations of symmetric primitives in various circumstances, especially software implementations. For known fault analyses, the bias over the faulty value or the relationship between the correct value and the faulty one, both produced by the fault injection serve as the foundations for the fault model. In the LFA, however, a single fault involves two intermediate values. The faulty target variable, u2˘7u\u27, is linked to a second variable, vv, such that a particular relation holds: u2˘7=l(v)u\u27=l(v). We show that LFA lets the attacker perform fault attacks without the input control, with much fewer data than previously introduced fault attacks in the same class. Also, we show two approaches, called LDFA and LIFA, that show how LFA can be utilized in the presence or absence of typical redundant-based countermeasures. Finally, we demonstrate that LFA is still effective, but under specific circumstances, even when masking protections are in place. We performed our attacks against the public implementation of AES in ATMEGA328p to show how LFA works in the real world. The practical results and simulations validate our theoretical models as well
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