Synthesis and characterization of Co-MOF@Ag2O nanocomposite and its application as a nano-organic catalyst for one-pot synthesis of pyrazolopyranopyrimidines.

In this study, a Co-MOF was synthesized via a co-precipitation procedure and then used as support for stabilizing Ag ions and producing Co-MOF@Ag2O nanocomposite by microwave irradiation. The characterization of synthesized Co-MOF@Ag2O nanocomposite was performed by using different techniques such as field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) analyses, X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) and Fourier-transform infrared (FT-IR). The prepared Co-MOF@Ag2O nanocomposite was applied as a heterogeneous nano-catalyst in the synthesis of pyrazolopyranopyrimidines in water at 50 °C via the one-pot multicomponent reaction of ethyl acetoacetate, hydrazine hydrate, aromatic aldehydes and barbituric acid derivatives. Through this straightforward and effective protocol, different tricyclic fused pyrazolopyranopyrimidines were synthesized at high yields, and short reaction times, through an uncomplicated work-up process with no by-product. The Co-MOF@Ag2O nanocomposite has been effectively recycled for four consecutive cycles without appreciable loss in its activity. Cost-effectiveness, no need for column chromatography, mild conditions, catalyst recyclability, and eco-friendly nature make it a promising candidate compared to other methods.

Synthesis of pyridone derivatives using 2D rod like bifunctional Fe based MOF and CuO nanocomposites as a novel heterogeneous catalyst.

In this study, a new and efficient Rod-like bifunctional Fe-based MOF@CuO nanocomposites (RL BF Fe-based MOF@CuO NC) were synthesized as new and efficient heterogeneous catalyst through a simple method from easily available 1,3,5-benzenetricarbocylic acid linker, nitrate ferric as a source of iron and copper oxide (CuO) nanoparticles under microwave irradiation. The synthesized nanocatalysts were characterized with different techniques such as Brunauer-Emmett-Teller (BET), energy dispersive spectroscopy (EDS), field emission scanning electron microscopy (FE-SEM), mapping, transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The RL BF Fe-based MOF@CuO NC had relatively high specific surface area (203 m2 g-1) while exhibiting superparamagnetic properties. The catalytic activity of RL BF Fe-based MOF@CuO NC was explored in a facile and green methodology to prepare diverse N­amino-2-pyridones by one-pot four component reactions comprising aromatic aldehyde, malononitrile, methyl cyanoacetate and hydrazine hydrate within mild and solvent-free conditions. This protocol enjoys features like providing the final products during low reaction times in excellent yields under solvent-free conditions. The use of easily available and inexpensive reactants for the synthesis of the catalyst, environmental compatibility, low catalyst loading, fast and clean work-up and reusability of catalyst for several cycles with consistent activity are counted as the outstanding features of this procedure.

Voltammetric determination of vitamin B6 in the presence of vitamin C based on zinc ferrite nano-particles modified screen-printed graphite electrode.

The zinc ferrite nano-particles (ZnFe2O4) modified screen-printed graphite electrode (ZnFe2O4/SPGE) was used for the voltammetric determination of vitamin B6 in real samples, using differential pulse voltammetry (DPV). It has been found that the oxidation of vitamin B6 at the surface of such an electrode occurs at a potential about 150 mV less positive compared to an unmodified screen-printed graphite electrode. After optimization, a vitamin B6 sensor with a linear range from 0.8 to 585.0 µM and a detection limit of 0.17 µM. The ZnFe2O4/SPGE sensor exhibits good resolution between the voltammetric peaks of vitamin B6 and vitamin C, making it suitable for detecting vitamin B6 in the presence of vitamin C in real samples.

Fe3O4@iron-based metal-organic framework nanocomposite [Fe3O4@MOF (Fe) NC] as a recyclable magnetic nano-organocatalyst for the environment-friendly synthesis of pyrano[2,3-d]pyrimidine derivatives.

Various pyrano[2,3-d]pyrimidines were synthesized by the multicomponent reaction of aldehydes, malononitrile, and acidic C-H compounds such as barbituric acid through the tandem Knoevenagel-Michael cyclocondensation pathway in an environmentally friendly reactive medium in the presence of a recoverable nanocomposite. This nanocomposite includes Fe3O4 nanoparticles placed on an organometallic framework. The synthesized Fe3O4@iron-based metal-organic framework nanocomposite was characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray powder diffraction, a vibrating sample magnetometer, and thermogravimetric analysis.

Green Synthesis of Polylactic acid/Fe3O4@ß-Cyclodextrin Nanofibrous Nanocomposite Loaded with Ferulago Angulata Extract as a Novel Nano-biosorbent: Evaluation of Diazinon Removal and Antibacterial Activity.

Background: Organophosphate pesticides are one of the most extensively applied insecticides in agriculture. These insecticides persist in the environs and thereby cause severe pollution problems. Iron oxide polymer nanocomposites are wastewater remediation agents synthesized by various methods. When compared to chemical processes, green synthesis using plant extract is thought to be more cost- and environmentally-friendly. Objectives: This study aimed to evaluate the green synthesis of Fe3O4@ß-Cyclodextrin (Fe3O4@ß-CD) nanoparticles using Ferulago angulata (F. angulata) methanol extract. These nanoparticles are loaded on polylactic acid (PLA) nanofibrous nanocomposite along with Ferulago angulata extract (2, 4, and, 6wt %) to produce PLA/Fe3O4@ß-CD/F. angulata extract nanofibrous nanocomposite as a new nano biosorbent. Furthermore, the antibacterial properties of this compound and its activity in diazinon removal have been evaluated. Materials and Methods: Fe3O4@ß-CD nanoparticles synthesis was performed via co-precipitation method using FeCl3.6H2O and FeCl2.4H2O and ß-cyclodextrin, and Ferulago angulata extract. Then polylactic acid/ Fe3O4@ß-CD / F. angulate.extract nanofibrous nanocomposite was prepared by the electrospinning method. Energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction analysis (XRD), vibrating sample magnetometer (VSM), and Fourier transform infrared spectroscopy (FTIR) were used to analyze the structure of the nanocomposite. The antibacterial activity of this nanocomposite against several fish and human bacterial pathogens, as well as its effectiveness in diazinon elimination, have been evaluated in the sections that follow. Results: The nanocomposite structure demonstrated that Fe3O4 nanoparticles were produced and put into the polylactic acid matrix with an average particle size of 40 nm. Furthermore, the results showed that this nanocomposite exhibited removal efficiency of diazinon over 80% after 120 minutes under pH=7 and 2.5 gr.L-1 nanocomposite concentration. Also, this structure showed above 70% antibacterial ability against Bacillus cereus, Staphylococcus epidermidis and 60% antibacterial ability against Streptococcus iniae and Yersinia ruckeri. Conclusion: Fe3O4 nanocomposite synthesis may be accomplished in a delicate and efficient manner by using Ferulago angulata to produce Fe3O4@-CD nanoparticles. The stability of the nanoparticles was enhanced by combining Ferulago angulata extract with polylactic acid nanofibers to create an antibacterial homocomposition nanocomposite. This device may be used to remove and disinfect diazinon from aqueous media in an environmentally friendly manner.

Microwave-assisted synthetic method of novel Bi2O3 nanostructure and its application as a high-performance nano-catalyst in preparing benzylidene barbituric acid derivatives.

In this study, controllable and optimal microwave irradiation has been used to synthesize the novel nanostructures of Bi2O3 under environmental conditions. The final products had a thermal stability of 210°C, an average particle size distribution of 85 nm, and a surface area of 783 m2/g. The high thermodynamic stability of Bi2O3 nanostructures was confirmed by TG and differential scanning calorimetry (DSC) analyses. The nanostructure nature of compounds, and most importantly, the use of an effective, cost-effective, and rapid synthesis route of microwave have created significant physiochemical properties in the Bi2O3 products. These unexpected properties have made the possibility of potential application of these products in various fields, especially in nano-catalyst applications. It is well-documented that, as Lewis acid, bismuth nano-catalyst exhibits a great catalytic activity for the green synthesis of some bio-active barbituric acid derivatives using precursors with electron-donating or electron-withdrawing nature in high yields (80%-98%). After incorporating this catalyst into the aqueous media, all the reactions were completed within 2-3 min at room temperature. The main advantages of this method are practical facility, the availability of starting materials, and low costs besides the catalyst reusability. Additionally, the catalyst synthesis process may be carried out in the aqueous media for a short period with medium to high yields. The obtained results have opened a new window for the development of a novel nano-catalyst with practical application.

Electrochemical Sensor Based on ZnFe2O4/RGO Nanocomposite for Ultrasensitive Detection of Hydrazine in Real Samples.

We have developed a highly sensitive sensor of ZnFe2O4/reduced graphene oxide (ZnFe2O4/RGO) nanocomposite for electrochemical detection of hydrazine, fabricated by a simple hydrothermal protocol. Subsequently, a screen-printed electrode (SPE) surface was modified with the proposed nanocomposite (ZnFe2O4/RGO/SPE), and revealed an admirable electrocatalytic capacity for hydrazine oxidation. The ZnFe2O4/RGO/SPE sensor could selectively determine micromolar hydrazine concentrations. The as-produced sensor demonstrated excellent ability to detect hydrazine due to the synergistic impacts of the unique electrocatalytic capacity of ZnFe2O4 plus the potent physicochemical features of RGO such as manifold catalytic sites, great area-normalized edge-plane structures, high conductivity, and large surface area. The hydrazine detection using differential pulse voltammetry exhibited a broad linear dynamic range (0.03-610.0 µM) with a low limit of detection (0.01 µM).

Screen-Printed Electrode Surface Modification with NiCo2O4/RGO Nanocomposite for Hydroxylamine Detection.

We developed a novel hydroxylamine sensor through the surface modification of screen-printed electrode (SPE) with NiCo2O4 nanoparticles/reduced graphene oxide (RGO) nanocomposite (NiCo2O4/RGO/SPE). We assessed the electrochemical response of hydroxylamine on the as-fabricated sensor, confirming the high electrocatalytic impact of hydroxylamine oxidation. The electrode produced sensitively responded to hydroxylamine under optimized conditions, with a low limit of detection (2.0 nM) and broad linear dynamic range (0.007-385.0 µM). The presence of NiCo2O4 combined with the modification of RGO resulted in sensitive detection and signal amplification of hydroxylamine oxidation. The proposed sensor was used to determine the existence of hydroxylamine in water samples.

Green Synthesis of Highly Dispersed Zinc Oxide Nanoparticles Supported on Silica Gel Matrix by Daphne oleoides Extract and their Antibacterial Activity.

BACKGROUND: ZnO nanoparticles (ZnO-NPs) are one of the most popular metal oxide nanoparticles, which exhibit significant antibacterial properties against various pathogens. Among nanoparticle synthesis methods, the green synthesis using plant extract is considered as an eco-friendly and cost-effective method for ZnO-NPs production, compared to the chemical procedures. BACKGROUND: This study aimed to evaluate the green synthesis of ZnO-NPs loaded on silica gel matrix (ZnO/SG nanocomposite) by using methanol leaf extract of Daphne oleoides as a new extract and a cost-effective method. Furthermore, the antibacterial activity of the synthesized structure is evaluated against some pathogenic bacteria and the results are compared with unsupported ZnO-NPs. MATERIALS AND METHODS: For ZnO/SG nanocomposite synthesis, a solution of Zn (NO3)2 was stirred with silica gel. Then the Daphne oleoides extract was added and stirred continuously until white precipitate was formed. The precipitate was heated at 200 ˚C for calcination, and ZnO/SG nanocomposite was obtained. The phytochemical constituents of leaf extract were then analyzed by gas chromatography-mass spectrometry (GC-MS). Afterwards, the structure of ZnO-NPs on SiO2 matrix (ZnO/SG nanocomposite) was characterized by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction analysis (XRD), and Fourier transform infrared spectroscopy (FTIR). Surface area measurement was also determined by Brunauer-Emmett-Teller (BET) techniques. Furthermore, the antibacterial activity of ZnO/SG nanocomposites against pathogenic bacteria was evaluated using agar-based disk diffusion method standardized by clinical and laboratory guidelines. RESULTS: The leaf extract of Daphne oleoides encompassed five major polyphenolic components. The results of the nanocomposite structure showed that ZnO-NPs with an average particle size of 38 nm were obtained and stabilized on the silica gel matrix. The BET surface area measurement of ZnO/SG nanocomposite was compared with unsupported ZnO-NPs, and the results indicated that the surface area of ZnO/SG nanocomposite was increased. Furthermore, the structure showed more powerful antibacterial activity against pathogens than unsupported ZnO-NPs. CONCLUSIONS: Green synthesis of ZnO-NPs supported on the silica gel matrix with the leaf extract of Daphne oleoides is a benign and effective procedure for ZnO/SG nanocomposite synthesis. Embedding ZnO-NPs in silica gel matrix prevents the agglomeration of nanoparticles and prepare homodispersed nanoparticles. This structure revealed great antibacterial activity against many pathogens.

Simulation and surface topology of activity of pyrazoloquinoline derivatives as corrosion inhibitor on the copper surfaces.

In the present study, corrosion inhibition performances of some pyrazolo [3,4-b] quinoline-3,5-dione derivatives against the corrosion of copper metal were investigated using B3LYP/6-311++g(d,p) calculation level in aqueous media. Additionally, interaction energies were calculated for all the pyrazoloquinoline derivatives compounds. In the calculations it is observed that studied molecules adsorb on metal surface with the help of electron donor heteroatoms in their molecular structures. Chemical thermodynamic parameters regarding the interaction between inhibitor molecule and copper surface were estimated and discussed. Density of the electron profile analysis and chemical electrostatic potential of nuclear charges in the molecule were applied to consider the nature of a number of probable interactions between Cu metal surface and inhibitors in terms of bond critical point (BCP). Calculated quantum chemical parameters showed that the pyrazoloquinoline derivatives including the OH and NO2 exhibit high inhibition performance.

4-Hydroxy Pyridinium Triflate@SiO2 Nanoparticles as a Novel Efficient Catalyst for Fries Rearrangement of Aryl Esters with High Selectivity.

INTRODUCTION: We developed a simple, fast and new method for the Fries rearrangement of aryl esters. MATERIALS AND METHODS: 4-Hydroxy pyridinium triflate functionalized silica is a very efficient, reusable and economically available catalyst for the Fries rearrangement in solvent-free condition and under microwave irradiation. RESULTS AND DISCUSSION: Also, a notable selectivity was observed in the presence of 4-hydroxy pyridinium triflate functionalized silica. CONCLUSION: Selectivity, shorter reaction time, high yield, and easy work-up are advantages of this synthetic method.

The Effect of l-Arginine on Dural Healing After Experimentally Induced Dural Defect in a Rat Model.

BACKGROUND: Incomplete repair of the dura mater may result in numerous complications such as cerebrospinal fluid leakage and meningitis. For this reason, accurate repair of the dura mater is essential. In this study, the effect of systemic and local supplementation of l-arginine on dural healing was evaluated. METHODS: Thirty male Wistar rats were used and divided into control, local, and systemic l-arginine groups, with 10 rats in each. In each group, a 5-mm experimental incision was made at the lumbar segment of the dura mater and cerebrospinal fluid leakage was induced. Each group was divided into 2 subgroups and at the end of the first and sixth weeks, the rats were killed and the damaged segments of the dura were separated, histologically evaluated and the dural healing indicators including cell types, granulation tissue formation, collagen deposit, and vascularization were compared between groups. RESULTS: The systematic supplementation of l-arginine showed a significant effect in dural healing compared with the control group. After the first week, granulation formation increased considerably (P < 0.031), and after 6 weeks, collagen deposition and neovascularization were significantly different compared with the control group (P < 0.030; P < 0.009). In comparison between different groups at the end of the first and sixth weeks, maximum changes in healing indicators were observed in the systemic group and the least variations were related to the control group. CONCLUSIONS: The systemic supplementation of l-arginine may accelerate dural healing by increasing the level of granulation tissue formation, collagen deposition, and vascularization.

Evaluation of argyrophilic nucleolar organizer region staining in predicting the behavior of meningiomas.

BACKGROUND: The number of argyrophilic nucleolar organizer regions (AgNOR) correlates with cellular proliferative activity. Comparing nonrecurrent, recurrent, atypical and malignant meningiomas we studied the value of the routine applicability of the AgNOR count in the prognostication of this tumor. PATIENTS AND METHODS: Two hundred and thirty-eight meningiomas were reviewed blindly and graded using WHO grading schema. Eighty-one cases were selected and arranged in six groups according to clinical data and grading: 14 benign non-recurrent meningiomas; 14 primary benign recurrent meningiomas and their subsequent benign recurrences; 14 atypical; 11 malignant and 14 spinal meningiomas. Silver-stained slides were prepared and mean, median and standard deviation of AgNOR dots determined. RESULTS: There was a proportionate increase of AgNOR dots with increasing tumor grade. There was a significant difference between benign non-recurrenttumors versus benign recurrent (P<0.0001) and atypical or malignant (P<0.0001) tumors. A difference was also noted between the recurring tumors versus malignant ones (P = 0.002) but no significant difference was seen between recurrent and atypical; atypical and malignant; intracranial and intraspinal; and primary of recurring meningiomas with their subsequent recurrences. A mean AgNOR count of <2.3 could separate benign tumors from atypical or malignant meningiomas with 93% specificity; and 93% of tumors with benign histology had no recurrence potential if their mean AgNOR count was less than 1.8. CONCLUSION: This study indicates that in meningioma, the AgNOR count has a good correlation with tumor grading and recurrence, which may aid pathologists and clinicians in predicting tumor behavior.

Neck mass as the first presentation of testicular choriocarcinoma.

Choriocarcinoma is a highly malignant tumor of the testis and usually occurs as a component of mixed germ cell tumor. The testicular enlargement may be subtle, and the patient may present with metastasis, the neck being one of its least reported locations. A case of testicular choriocarcinoma in a 24-year-old man who presented for the first time with metastatic neck mass is reported here. This presentation, although very rare, can be a great diagnostic and therapeutic challenge and should be considered in the differential diagnosis of cervical masses occurring in young males.