Determination of histamine levels in fresh fish using Near Infrared (NIR) technology

Fresh fish and fish products are highly perishable food. Development of fast, secure and non- destructive technique for estimation the presence and quantity of components which are related with safety of food products is of great interest for science but also and for the industry sector. Above-mentioned idea is the aim of this research work, precisely, determination of histamine levels in fresh fish with the use of different near infrared handheld devices. Histamine is one of biogenic amines among putrescine, cadaverine, tyramine which are non-volatile amines produced post mortem and are formed from decarboxylation of specific free amino acids in fish or shellfish tissue. Reason why we choose to developing technique for evaluation of histamine levels is EU Regulation 2073/2005 requires the determination of histamine at three different levels: 100, 200 and 400 mg/kg. For reaching the goal we decided to use paper-based technology for collecting samples for evaluation using Whatman grade 2 qualitative filter papers. In the first phase for validation of NIR devices specifications, and for creation of calibration curve we used histamine solution with 0.5, 1, 2.5 and 5 %. Results showed regression of R2 = 0.69 which indicates that NIR devices can be promising tools for spotting histamine beside small molecular weight

Chemical Bath Coating and Characterisation of Electrochromic Manganese(II) Carbonate Thin Films

A chemical bath technique for manganese(II) carbonate thin films deposition on electroconductive FTO – layered glass substrates is described in this report. Homogeneous thin films were obtained from an aqueous solution containing H2NCONH2 and MnCl2. The deposition is performed at temperature of 98 °C. The chemistry background of the process is the hydrolysis of urea [1,2]. Thin films were studied using X-ray diffraction, Profilometry, Cyclic Voltammetry (CV) and UV/VIS spectrophotometry. A combination of electrochemical and optical measurements has revealed electrochromic behaviour. By means of X-ray diffraction measurements the structure, crystallinity and the chemical composition, corresponding to manganese(II) carbonate, have been determined. Thin films thicknesses were determined using Profilometry. Keywords: manganese(II) carbonate, thin films, electrochromic materials, chemical bath deposition method

Electrochromic K0.27MnO2 · 0.6H2O Thin Films Deposition on Glass Substrates using Dip Coating Method

Electrochromic thin films were deposited on electroconductive FTO - layered glass substrates using dip coating method [1]. Substrates were subsequently immersed in aqueous solutions of MnCl2 and KMnO4 in order to obtain thin films with different thicknesses. The obtained thin films were characterized using several methods. X-ray investigations were made to verify theirs structures, crystallinity and the chemical composition. The results showed that the chemical compound corresponds to K0.27MnO2·0.6H2O [2,3]. Thin films electrochemical behaviour was investigated using Cyclic Voltammetry (CV). Examination of thin films electrochromic properties showed reversible redox transformation accompanied with colour change. Optical measurements were carried out with UV/VIS spectrophotometer in order to ascertain redox induced changes in the VIS transmittance spectra. Thin films thicknesses and surface morphology were determined using Profilometry and AFM technique. Keywords: thin films, K0.27MnO2·0.6H2O, electrochromism, dip coating method

A simple chemical method for deposition of electrochromic potassium manganese oxide hydrate thin films

A new chemical method for fast deposition of electrochromically active thin films of birnessite-type potassium manganese oxide (K0.27MnO2·xH2O) has been developed. The chemical deposition has been performed at room temperature by a reaction of aqueous solutions of potassium permanganate and manganese(II) chloride. The prepared thin films have thickness from 50 to 250 nm depending on the number of the deposition cycles. The composition and the structure of the K-birnessite films are studied by XRD, IR spectroscopy and TG/DTA analyses. Electrochemical studies using four different electrolytes such as aqueous K2SO4, Li2SO4, KNO3, and LiClO4 in PC have been performed. The electrochromic activity has been explored by cyclic voltammetry and VIS spectrometry. The best electrochromic properties are obtained using aqueous KNO3, where the difference in the transmittance at 400 nm between the bleached and colored state is 40% for both as-deposited and annealed films. The obtained data allow the prepared K-birnessite thin films in aqueous KNO3 electrolyte to be proposed as a promising system for electrochromic applications

Preparation of electrochromic thin films by transformation of manganese(II) carbonate

A new chemical bath method for deposition of manganese(II) carbonate thin film on electroconductive FTO glass substrates is designed. The homogeneous thin films with thickness in the range of 70 to 500 nm are deposited at about 98 °C from aqueous solution containing urea and MnCl2. The chemical process is based on a low temperature hydrolysis of the manganese complexes with urea. Three types of films are under consideration: as-deposited, annealed and electrochemically transformed thin films. The structure of the films is studied by XRD, IR and Raman spectroscopy. Electrochemical and optical properties are examined in eight different electrolytes (neutral and alkaline) and the best results are achieved in two component aqueous solution of 0.1 M KNO3 and 0.01 M KOH. It is established that the as-deposited MnCO3 film undergoes electrochemically transformation into birnessite-type manganese(IV) oxide films, which exhibit electrochromic color changes (from bright brown to pale yellow and vice versa) with 30% difference in the transmittance of the colored and bleached state at 400 nm

Strengthening of biotechnological education in Macedonia as an important development component

Biotechnology is a discipline which is applied in different areas such as: food production and processing, pharmaceutical industry, diagnostics etc. By strengthening of biotechnological education in Macedonia (SBEM) can be improved and modernized this field of education in order to meet the industry needs in the country. SBEM will be coordinated by the Faculty of Technological Sciences as a part of the “Mother Teresa” University in Skopje and it will include vocational high schools dealing with biotechnology in the Republic of Macedonia and appropriate clusters in the frame of Commercial Chambers. The main objective is to improve teachers’ and trainers’competences and their ability to provide eLearning in-service vocational training courses for biotechnology secondary school teachers. Putting together of all stakeholders in biotechnological education will be done by establishment of a National Data for Biotechnological Education of Macedonia (NDBEM). Different type of training (courses, workshops, seminars) will be held at each faculty in e-learning way using active teaching/learning (ATL) approach. The trainings will be given by International and domestic experts in biotechnological education. ATL is important for university staff and vocational teachers as they had no pedagogical training during their graduate courses. University teachers will develop and implement classical and online vocational courses targeting recent advances in biotechnology for biotechnology teachers in VET schools. Previously, the market survey should be done in order to analyze the need of a real technological sector in cooperation with Commercial Chambers. NDBEM will be formed using assistance from Graz university and it will be used as a repository for online courses and teaching resources developed during trainings of university and teachers in biotechnology vocational education and training (BVET). Project deliverables will be stored and available in the NDBEM for future users. Its sustainability need to be provided by its recognition from the Ministries of Education and Science. SBEM will have the following specific objectives: improvement of quality and availability of vocational education; strengthening of professional and pedagogical competences of educators and trainers; and creation of the “open source“ repository for educators in the area of biotechnological educatio