Electrochemical characterisation of 3Y-TPZ-Fe2O3 composites

The influence of the addition of ferric oxide to 3Y-TZP on the conductivity and microstructure of sintered Y-stabilised tetragonal zirconia ceramics (3Y-TZP) was investigated. A comparison was made between two different dense 3Y-TZP¿¿-Fe2O3 composites. Compacts were made by pressureless sintering at 1150 °C or by sinterforging at 1000 °C and 100 MPa. The sinterforging process resulted in smaller zirconia and hematite grains and a higher monoclinic zirconia content as compared to the compact that was sintered pressureless. The high monoclinic content led to loss of ionic conductivity. The addition of ferric oxide caused electronic conductivity. The sinterforging resulted in a high concentration of metastable defects in the zirconia¿hematite composite, leading to a relatively high electronic conductivity. Heating above 380 °C caused irreversible loss of these defects and a large decrease in electronic conductivity

The synthesis of nano-nano dual phase ceramic composites

Nano-nano dual-phase composites in which both phases are present as grains with typical dimensions <100 nm are expected to exhibit physical properties, deviating from those of coarser-grained composites. If one phase is electron conducting and the other electrically isolating, special properties can be expected due to Schottky-barrier space-charge formation in the isolator phase near dual-phase boundaries. The extent of the Schottky-barrier (Debije length) can be of the same order as the total grain dimension resulting in special electrical and optical properties. These expectations are the base of this research

Molecular cloning of an insect pheromone-binding protein

AbstractClones coding for the pheromone binding protein precursor have been selected from a cDNA library derived from antennae of the male moth, Antheraea polyphemus. The deduced protein sequence consists of a signal peptide of 20 amino acid residues and a mature binding protein of 142 amino acid residues. RNA blot hybridization indicated that the mRNA is selectively expressed in the antennae of the male moth.Pheromone binding protein; cDNA cloning; Nucleotide sequence; Primary structure; RNA blot hybridizatio

Synthesis and Magnetic Properties of Cobalt Ferrite (CoFe2O4) Nanoparticles Prepared by Wet Chemical Route

Magnetic nanoparticles of cobalt ferrite have been synthesized by wet chemical method using stable ferric and cobalt salts with oleic acid as the surfactant. X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM) confirmed the formation of single phase cobalt ferrite nanoparticles in the range 15-48nm depending on the annealing temperature and time. The size of the particles increases with annealing temperature and time while the coercivity goes through a maximum, peaking at around 28nm. A very large coercivity (10.5kOe) is observed on cooling down to 77K while typical blocking effects are observed below about 260K. The high field moment is observed to be small for smaller particles and approaches the bulk value for large particles.Comment: 18 pages, accepted in JMMM, (May, 2006

A novel brain receptor is expressed in a distinct population of olfactory sensory neurons

Three novel G-protein-coupled receptor genes related to the previously described RA1c gene have been isolated from the mouse genome. Expression of these genes has been detected in distinct areas of the brain and also in the olfactory epithelium of the nose. Developmental studies revealed a differential onset of expression: in the brain at embryonic stage 17, in the olfactory system at stage E12. In order to determine which cell type in the olfactory epithelium expresses this unique receptor type, a transgenic approach was employed which allowed a coexpression of histological markers together with the receptor and thus visualization of the appropriate cell population. It was found that the receptor-expressing cells were located very close to the basal membrane of the epithelium; however, the cells extended a dendritic process to the epithelial surface and their axons projected into the main olfactory bulb where they converged onto two or three glomeruli in the dorsal and posterior region of the bulb. Thus, these data provide evidence that this unique type of receptor is expressed in mature olfactory neurons and suggests that it may be involved in the detection of special odour molecules

Using Orbitrap mass spectrometry to assess the isotopic compositions of individual compounds in mixtures

The isotopic compositions of individual chemical species are routinely used by the geochemical, environmental, forensic, anthropological, chemical, and biomedical communities to elucidate the conditions, sources, and reaction pathways of the molecules in question. Mass spectrometric methods of measuring isotopic compositions of individual compounds generally require that analytes be pure to yield precise, accurate results, yet most applications examine materials that are mixtures of multiple components. Various methods of chemical purification, e.g., chromatography, are used to isolate analytes from mixtures prior to mass spectrometric analysis. However, these techniques take time and specialized instrumentation, both of which could potentially be obviated via the use of ultra-high-resolution mass spectrometry. Here we report on the use of Orbitrap™-based Fourier-transform mass spectrometry to perform isotope ratio measurements of single species within mixtures delivered to the mass spectrometer (MS) without prior chromatographic separation. We demonstrate that instrument biases (attributed here to space charge effects) within the Orbitrap mass analyzer can cause the measured ¹³C/¹²C ratio of a molecular ion in the presence of non-analyte-derived ‘contaminating’ species to spuriously decrease relative to the ¹³C/¹²C ratio measured for the same ion in a pure analyte. We observe that the decrease in ¹³C/¹²C is proportional to the relative concentrations of the additional ‘contaminating’ components. We then recommend several strategies by which this effect can be mediated such that accurate isotope ratios can be obtained

Using Orbitrap mass spectrometry to assess the isotopic compositions of individual compounds in mixtures

The isotopic compositions of individual chemical species are routinely used by the geochemical, environmental, forensic, anthropological, chemical, and biomedical communities to elucidate the conditions, sources, and reaction pathways of the molecules in question. Mass spectrometric methods of measuring isotopic compositions of individual compounds generally require that analytes be pure to yield precise, accurate results, yet most applications examine materials that are mixtures of multiple components. Various methods of chemical purification, e.g., chromatography, are used to isolate analytes from mixtures prior to mass spectrometric analysis. However, these techniques take time and specialized instrumentation, both of which could potentially be obviated via the use of ultra-high-resolution mass spectrometry. Here we report on the use of Orbitrap™-based Fourier-transform mass spectrometry to perform isotope ratio measurements of single species within mixtures delivered to the mass spectrometer (MS) without prior chromatographic separation. We demonstrate that instrument biases (attributed here to space charge effects) within the Orbitrap mass analyzer can cause the measured ¹³C/¹²C ratio of a molecular ion in the presence of non-analyte-derived ‘contaminating’ species to spuriously decrease relative to the ¹³C/¹²C ratio measured for the same ion in a pure analyte. We observe that the decrease in ¹³C/¹²C is proportional to the relative concentrations of the additional ‘contaminating’ components. We then recommend several strategies by which this effect can be mediated such that accurate isotope ratios can be obtained

Pelatihan Pengerjaan Tes Kemampuan Akademik (TKA) Bidang Matematika Untuk Siswa Kelas 12 SMA Kota Samarinda

Perguruan Tinggi Negeri (PTN) adalah salah satu jenjang studi tujuan dari siswa SMA setelah lulus. Lembaga yang menjadi penyelenggara tes masuk perguruan tinggi bagi calon mahasiswa baru yaitu Lembaga Tes Masuk Perguruan Tinggi (LTMPT). Berdasarkan data LTMPT Tahun 2021 yang dapat diakses di top-1000-sekolah.ltmpt.ac.id, 5 peringkat peraih nilai Ujian Tulis Berbasis Kompetensi secara nasional tertinggi berasal dari SMA/sederajat dari Jawa. Sedangkan SMA/sederajat di Kota Samarinda menempati peringkat mulai dari 419. Hal ini dikhawatirkan menurunkan daya saing siswa/i Kota Samarinda untuk diterima di perguruan tinggi negeri. Oleh karena itu, dalam pengabdian masyarakat ini akan dilakukan Pelatihan Tes Kemampuan Akademik (TKA) Bidang Matematika untuk siswa kelas 12 SMA Kota Samarinda. Dengan harapan untuk memberikan pengalaman dan pemahaman Tes Kemampuan Akademik kepada Siswa/i kelas 12 Kota Samarinda. Kota Samarinda dipilih karena kemudahan akses dan siswa kelas 12 SMA dipilih karena termasuk peserta didik tingkat akhir. Metode pelatihan yang digunakan adalah tatap muka, ceramah, latihan dan diskusi. Peserta diberikan tes awal sebelum pelatihan dan peserta diberikan tes akhir setelah pelatihan. Data tes awal dan tes akhir dianalisis menggunakan statistika deskriprif dan uji beda rata-rata. Hasilnya terdapat perbedaan rata-rata pada tes awal dan tes akhir, dan rata-rata tes awal < rata-rata tes akhir. Artinya tim pengabdian kepada masyarakat berhasil memberikan pengalaman dan pemahaman kepada peserta pelatihan Tes Kemampuan Akademik di Kota Samarinda