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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).

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.

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.

In this study, Co3O4 nanocatalysts were constructed in environmentally appropriate conditions using controlled, effective, and facile microwave method. The final nanostructures were characterized by SEM, XRD, and TEM analyses. The products had a small size distribution, homogeneous morphology, and crystallographic structures associated with the formation of Co3O4 nanostructures. Moreover, EDS mapping analysis confirmed the existence of Co and O elements in the final structure, and the magnetic properties of the samples were investigated by VSM. The application of this nanostructure in a catalytic process was further examined, and the results suggested that it could be used as a novel candidate for the synthesis of arylidene barbituric and Meldrum,s acid through Knoevenagel condensation of aldehydes by barbituric and Meldrum,s acid in aqueous media. The high yield of these nanocatalysts would be justified by the nature of the nanostructure as well as the experimental procedure developed in this study, which affected the physicochemical features of the products.

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A convenient synthesis of functionalized 2-iminothiazolidin-4-ones and thiadiazoloquinazolinones has been achieved by the reaction of dialkyl acetylenedicarboxylates (DAAD) with 1-pheny-3-pyridin-2-yl-thiourea (1) and 3-amino-2-mercapto-3H-quinazolin-4-one (8), respectively. The starting materials for these processes were prepared from phenyl isothiocyanate, 2-aminopyridine for (1) and anthranilic acid, carbon disulfide, hydrazine for (8). Treatment of these compounds with DAAD resulted in the formation of an intermediate that readily underwent intramolecular cyclization to afford functionalized five membered heterocyclic rings was formed.

A series of novel tetracoumarin derivatives (3a-f) were prepared using the reaction of ether functionalized dibenzaldehyde with 4-hydroxycoumarin in the presence of sodium acetate. The structure of compounds was validated by IR, NMR, and CHN analyzes. Antimicrobial (antibacterial and antifungal) activity was studied on the basis of the minimum bactericidal concentration, minimum inhibitory concentration and inhibitory zone diameter. Favorable biological activity was found in compound 3f.