870 research outputs found

    Assessment of morphological and functional changes in neonate vitrified testis grafts after host treatment with melatonin

    Get PDF
    This study was conducted to assess the effect of melatonin on the structure of testis and spermatogenesis dynamics in neonate vitrified testis grafts. Neonate vitrified testes, candidates for transplantation heterotopically to experiment or control groups, were warmed in thawing media which had or did not have a supplement of 100 μM melatonin, respectively. Following transplantation, melatonin (20 mg/ /kg/day) or saline solution was intraperitoneally injected into the treated and the non-treated groups, respectively. The initiating spermatogenesis, spermatogonia survival, and structure of tissue in the testis graft were examined. Cell apoptosis (TUNEL assay) and proliferation (Brdu assay) in germ cells were determined. Histological studies revealed the dynamic of the spermatogenesis process in the vitrified testis graft. However, dilation of the lumen accompanied by a disorganised epithelium in the non-treated group was higher than in the treated group. Furthermore, the proportion of apoptotic germ cells together with a reduced proportion of proliferated germ cells was higher in the non-treated group than in the treated group. Overall, the number of seminiferous tubules in the testes grafts of both groups remained steady. However, the non-treated testes grafts contained more damaged seminiferous tubules than the treated ones. The thickness of the seminiferous tubules was greater in the melatonin treated group than in the non-treated group. In fact, the thickness of germinal epithelium was significantly higher in the treated group than in the non-treated group. The study may show a positive effect from melatonin resulting in more grafts restoring puberty. Furthermore, the associated increase in the healthy number of seminiferous tubules suggests that melatonin may have a preventative ischaemia/antioxidant role and in fact may be useful to initiate the spermatogenesis process. (Folia Morphol 2011; 70, 2: 95–102

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

    Get PDF
    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

    High Performance Magnetically Separable G‐C3N4/γ‐Fe2O3/TiO2 Nanocomposite with Boosted Photocatalytic Capability towards the Cefixime Trihydrate Degradation under Visible‐Light

    Get PDF
    A magnetically separable g‐C3N4/γ‐Fe2O3/TiO2 nanocomposite is synthesized as an intensely effectual visible‐light‐driven photocatalyst. It is fully characterized by FT‐IR, XPS, XRD, VSM, DRS, SEM, TEM, BET, EDS, and elemental mapping techniques. Based on the Tauc plot of (αhÎœ)2 vs. hυ, the value of band gap energy for g‐C3N4/γ‐Fe2O3/TiO2 is estimated to be 2.6 eV, which proves the high capability of the catalyst to enhance the photoinduced electron‐holes separation and improves its visible‐light photocatalytic performance. The high photocatalytic activity of this catalyst towards the cefixime trihydrate (CEF) degradation, under visible‐light radiation can be ascribed to the synergistic optical effects between g‐C3N4, γ‐Fe2O3, and TiO2. Using central composite design (CCD) based on response surface methodology (RSM), the maximum degradation efficiency of about 98 % was obtained at the optimal conditions comprising the CEF amount of 20 mg/L, photocatalyst value of 0.04 g/L, irradiation intensity of 9 W/m2, and pH of 5.5, at 90 min. Utilizing an innocuous visible‐light source, almost complete mineralization of CEF (based on TOC analysis), using a very low amount of photocatalyst, applying air as the oxidant, and convenient magnetic separation of the catalyst from the reaction media and its ease of recycling for at least seven consecutive runs are the major highlights of this protocol.Financial support of this project by the University of Birjand Research Council and the XPS facilities of the University of Alicante is appreciated

    A novel base-metal multifunctional catalyst for the synthesis of 2-amino-3-cyano-4H-chromenes by a multicomponent tandem oxidation process

    Get PDF
    A novel base-metal multifunctional nanomagnetic catalyst is prepared by the immobilization of tungstate anions onto Îł-Fe2O3 supported with imidazolium moieties. The (Îł-Fe2O3-Im-Py)2WO4 was fully characterized using FT-IR, XPS, TEM, FESEM, ICP, TGA, VSM and XRD and used as a multifunctional heterogeneous catalyst for the synthesis of 2-amino-3-cyano-4H-chromenes via a multicomponent tandem oxidation process starting from alcohols under solvent-free conditions. During this process, tungstate catalyzes the oxidation of a wide range of alcohols in the presence of TBHP as a clean source. The in-situ formed aldehydes are condensed with malononitrile and ÎČ-dicarbonyl compounds/naphthols/4-hydroxycumarin through promotion by pyridine and imidazolium moieties of the catalyst. By this method, a variety of 2-amino-3-cyano-4H-chromenes are generated in good to high yields from alcohols as inexpensive and easily available starting materials. The catalyst is recovered easily by the aid of an external magnetic field and reused in five successive runs with insignificant decreasing activity.We acknowledge the financial support for this research by the University of Birjand Research Council and also access to the XPS facilities of the Central Technical Services of the University of Alicante

    Chronic effects of aerobic exercise on gene expression of LOX-1 receptor in the heart of rats fed with high fat diet

    Get PDF
    Objective(s): Lectin-like low density lipoprotein receptor (LOX-1) has pivot role in vascular complications, which is upregulated in numerous pathological conditions. Since exercise has beneficial effects in prevention of hyperlipidemic complications, present study examined protective effects of aerobic exercise through reduction of LOX-1 expression in heart during dyslipidemia. Materials and Methods: Four groups of rats were used (N=25): Normal, Normal and exercise, High fat and High fat and exercise. High fat diet (HFD) was made by adding 10 animal oil, 2 cholesterol and 0.5 colic acid to standard rodent chow. Exercise protocol consisted of swimming 1 hr/day, and 5 days/week for 8 weeks. Plasma lipids were evaluated at the end of experiment, 48 hr after final session of exercise. At the end, rats were sacrificed and heart was removed for determination of malondialdehyde (MDA) content, and LOX-1 expression. Results: HFD meaningfully changed lipid profile (>50), but chronic exercise had no significant effects on lipid profile. LOX-1 expression was significantly increased in heart of rats fed with HFD, while swimming exercise considerably reduced gene expression of LOX-1. MDA content was significantly enhanced in rats fed with HFD (4.37±0.6 nmol/mg, P<0.01) compared to normal group (1.56±0.48 nmol/mg), whereas swimming exercise decreased MDA level of heart in rats fed with HFD (2.28±0.32, P<0.01). Conclusion: Findings indicated that swimming exercise is able to diminish heart expression of LOX-1 receptor concomitant reduction of oxidative stress. Since these parameters are involved in generation of dyslipidemic complications, swimming exercise is a good candidate to reduce these complications. Copyright 2015, Mashhad University of Medical Sciences , All Rights Reserved

    Water-Dispersible Pd–N-Heterocyclic Carbene Complex Immobilized on Magnetic Nanoparticles as a New Heterogeneous Catalyst for Fluoride-Free Hiyama, Suzuki–Miyaura and Cyanation Reactions in Aqueous Media

    Get PDF
    Pd–N-heterocyclic carbine complex immobilized on magnetic nanoparticles is synthesized and characterized by different techniques such as FT-IR, XPS, TEM, EDX, FESEM, VSM, TGA, and ICP. The synthesized catalyst was used as a new water dispersible heterogeneous catalyst in the fluoride-free Hiyama, Suzuki–Miyaura and cyanation reactions in pure water. By this method, different types of biaryls and aryl nitriles were synthesized in good to high yields by the reaction of a variety of aryl iodides, bromides and chlorides with triethoxyphenylsilane, phenylboronic acid and K4[Fe(CN)6]·3H2O, respectively. The presence of sulfonates as hydrophilic groups on the surface of the catalyst confers a highly water dispersible, active and yet magnetically recoverable Pd catalyst. The possibility to perform the reaction in water as a green medium, ease of the catalyst recovery and reuse by magnetic separation, and the absence of any additives or co-solvents make this method as an eco-friendly and economical protocol for the synthesis of biaryl derivatives and aryl nitriles.We acknowledge the financial support for this research by the University of Birjand Research Council and also access to the XPS facilities of the Central Technical Services of the University of Alicante

    New Nanomagnetic Heterogeneous Cobalt Catalyst for the Synthesis of Aryl Nitriles and Biaryls

    Get PDF
    Cobalt nanoparticles immobilized on magnetic chitosan (Fe3O4@CS-Co) have been prepared. They were identified using various techniques such as Fourier-transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, thermogravimetric analysis, vibrating sample magnetometry, X-ray photoelectron spectroscopy, and inductively coupled plasma atomic emission spectroscopy analysis and applied efficiently as a cobalt catalyst in the cyanation and fluoride-/palladium-free Hiyama reactions of different types of aryl halides employing K4[Fe(CN)6]·3H2O and triethoxyphenylsilane, respectively. After each reaction, the catalyst was isolated and reused for the second run. The catalytic activity of the catalyst was not lost apparently even after five runs. No considerable changes in its chemical structure and morphology were observed. It is worth to note that in this paper, the cobalt catalyst has been used for the first time for the cyanation of aryl halides.Financial support for this project from the University of Birjand Research Council is acknowledged. Access to the XPS facilities of the Central Technical Services of the University of Alicante is appreciated

    Workshop: Lassoing unicorns: how to map capabilities for better interdisciplinary research

    Get PDF
    Sometimes doing interdisciplinary work feels like trying to lasso unicorns. Working with big players from foreign disciplines and interdepartmental drifters. Negotiating over language and frameworks. Agreeing common research questions. All the while trying to gather data and do good work. Building on methods developed in ESRC and Horizon 2020 funded projects on interdisciplinary research, this workshop will: a) introduce the concept interdisciplinary capabilities - the disciplinary skills and informal aptitudes needed for people like environmental engineers, ecological economists and machine learning developers to work well together. b) present a mixed-method approach to mapping capabilities using bibliometric analysis and interviews. c) offer hands-on reflexive exercises on personal ‘capability mapping’, tailored to workshop participants The session will help scholars of all levels recognise power and knowledge in research and identify opportunities to steer that research together
    • 

    corecore