Publications

Bio ceramics are being prepared by advanced 3D printing technology which is a very good economical technique. Different inorganic materials can be used to print bio ceramics for different applications such as alumina, zirconia, Leucite, lithium disilicate and mica-based ceramics. The main implications of bio ceramics are in dentistry and orthopedics.

Optimized surface-type impedimetric and capacitive proximity sensors have been fabricated on paper substrates by using rubbing-in technology. The orange dye (OD) and silicone glue (SG) composite-gel films were deposited on the zig-zag gap between two aluminum electrodes fixed on a paper (dielectric) substrate. The effect of proximity of various objects (receivers) on the impedance and the capacitance of the sensors was investigated. These objects were semi-cylindrical aluminum (metallic) foil, a cylindrical plastic tube filled with water, a kopeck-shaped plastic tube filled with carbon nanotubes and a human finger. The mechanism of sensing was based on the change in impedance and/or the capacitance of the sensors with variation of proximity between the surfaces of the sensor and the object. On decreasing proximity, the impedance of the sensors increased while the capacitance decreased. The impedimetric proximity sensitivities of CNT, water, metal-based receivers and the finger were up to 60 × 10³ Ω/mm, 35 × 10³ Ω/mm, 44 × 10³ Ω/mm and 6.2 × 10³ Ω/mm, respectively, while their capacitive sensitivities were -19.0 × 10^-2 pF/mm, -16.0 × 10^-2 pF/mm, -16.4 × 10^-2 pF/mm and -1.8 × 10^-2 pF/mm. If needed for practical application, the sensors can be built in to the Wheatstone bridge, which can also increase the sensitivity of the measurement. Moreover, the sensor's materials are low cost, while the fabrication technique is easy and ecologically friendly. The sensor can also be used for demonstrative purposes in school and college laboratories.

In this communication, we report on the first use of Ni₃Se₂film electrochemically deposited on Cu foam (Ni₃Se₂/CF) as a bifunctional catalyst for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) with good durability at alkaline media.

Au-Cu alloy nanoparticles were synthesized by a chemical reduction method. Five samples having different compositions of Au and Cu (Au-Cu 3 : 1, Au-Cu 2 : 1, Au-Cu 1 : 1, Au-Cu 1 : 2, and Au-Cu 1 : 3) were prepared. The newly synthesized nanoparticles were characterized by electronic absorption, fluorescence, and X-ray diffraction spectroscopy (XRD). These alloy nanoparticles were also analyzed by SEM and TEM. The particle size was determined by SEM and TEM and calculated by Debye Scherrer’s equation as well. The results revealed that the average diameter of nanoparticles gets lowered from 80 to 65 nm as the amount of Cu is increased in alloy nanoparticles. Some physical properties were found to change with change in molar composition of Au and Cu. Most of the properties showed optimum values for Au-Cu alloy nanoparticles of 1 : 3. Cu in Au-Cu alloy caused decrease in the intensity of the emission peak and acted as a quencher. The fluorescence data was utilized for the evaluation of number of binding sites, total number of atoms in alloy nanoparticle, binding constant, and free energy of binding while morphology was deduced from SEM and TEM.

Manganese oxide nano-particles have been synthesized by hydrothermal process using aqueous combination of manganese chloride and urea as starting materials, where ammonium hydroxide is used as a reducing agent to adjust the pH at 10.55. The structural investigation of the as-grown nano-crystalline manganese oxide is analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectrophotometer (FTIR), and Raman spectrophotometer, which revealed that the synthesized manganese oxide is well crystalline. Further, energy dispersive spectroscopy (EDS) confirms the composition of manganese oxide (Mn3O4) with Mn and O elements. UV-Visible absorption spectra (~293.44 nm) are used to investigate the optical properties of as-grown Mn3O4. The photocatalytic activity of the synthesized Mn3O4 is evaluated using color dye (Acridine Orange, AO), which degraded close to 47.38% in irradiation time (170 min). The chemical sensing of Mn3O4 coated electrodes has been primarily investigated by I-V technique, where ethanol is used as a model compound. The analytical performance of ethanol sensors exhibits the higher sensitivity (0.4777 μAcm-2mM-1) and a large linear dynamic range (0.17 μM to 0.17 M) in short response time (10.0 sec). Keywords: Mn3O4, XRD, FE-SEM, Photo-degradation, Acridine Orange, Ethanol sensor

Der Reaktionsmechanismus der industriell wichtigen Umwandlung von Methanol in Olefine über Zeolithkatalysatoren wurde untersucht. In der Zuschrift auf S. 16072 ff. zeigen M. Baldus, B. M. Weckhuysen et al. einen effektiven, auf Festkörper-NMR-Spektroskopie und Operando-UV/Vis-Spektroskopie basierenden Ansatz, um den Beweis für einen direkten Mechanismus bei der Bildung der ersten Kohlenstoff-Kohlenstoff-Bindung während der Anfangsphase der Reaktion zu liefern.

The synthesis of a series of 1,3,4,5-tetrahydro-2H-1,5-benzodiazepine has been achieved by reaction of DHA (dehydroacetic acid), o-PDA (o-phenylenediamine) and aromatic aldehydes in the presence of a catalytic amount of TFA (trifluoroacetic acid). Four molecules were crystallised and their structures determined using single crystal X-ray crystallography The 15-benzodiazepines derivatives were evaluated for their in vitro cytotoxic effects.