An early warning system approach for the identification of currency crises with data mining techniques

It is a well-known fact that currency crises can be extremely costly to the countries, institutions and businesses with its damaging long-term effects. If the history of currency crises is investigated, it would be seen that crises cause many hazarding effects on economies, business policies and assets. It would generally have short-term and long-term effects and often spill over, via a variety of channels to other countries and companies. In this study, it is aimed to investigate the dominant factors that lead to currency crises. Discovering the nature and characteristics of currency crises and predicting possible currency crises in an early phase would save managers some time in better crisis management policies and corrective actions. We employed data mining techniques to construct an early warning system for the knowledge discovery and early prediction purposes of currency crises with the aim of providing an in-depth understanding of the topic for the researchers and managers.     

Thermoresponsive hydrogels based on renewable resources

This work aims to synthesize novel thermoresponsive hydrogels from renewable resources, bacterial cellulose (BC), and castor oil (CO), and to investigate the effect of CO on physical and thermal behaviors of BC/Poly(N-isopropylacrylamide) (PNIPAM) hydrogels. The structural properties of the hydrogels are analyzed by Fourier-transform infrared (FTIR) spectroscopy. Differential scanning calorimeter (DSC) technique and thermogravimetric analysis (TGA) are also performed to examine the thermal properties of the hydrogels. The morphological differences of the hydrogels are analyzed by scanning electron microscope (SEM). The thermoresponsive performances of the hydrogels are examined by swelling and deswelling behaviors. The hydrogel with CO is found to be more sensitive to temperature changes than the one without CO. Deswelling study demonstrates 91 and 25% of water loss for hydrogels with and without CO, respectively. The present study shows a novel approach to synthesize thermoresponsive hydrogels with renewable resources for biomedical applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48861.     

Influence of vitamin (B1, B6, B9, B12, C) and ions (Cu2+, Mn2+, PO4 3−) on kefir grain biomass growth

The aim of the present study was to investigate the effects of additions of various vitamins (B₁, B₆, B₉, B₁₂, and C) and minerals (CuSO₄·H₂O, MnSO₄·H₂O, and Na₃PO₄·12 H₂O) on the propagation of kefir grains. The activated kefir grains were inoculated into very low fat (0.1%) cows’ milk under constant temperature (25°C) and impeller speed (100 rpm) for a propagation time of 24 h. After evaluation of the experimental data, the most influential mineral addition providing 39% increase of kefir grain biomass was found to be Na₃PO₄·12 H₂O with a concentration of 0.30 g phosphate (PO₄ ^3?) ion/L. At this optimal condition, a model was also derived for the kefir grain biomass concentration representing pH dependence. This study demonstrated the basis for further research in the direction of kefir grain biomass growth considering the effect of additions of vitamins and minerals to other researchers working in the same field and to dairy industry as well.     

Enzymatic cross-linking of β-lactoglobulin in solution and at air-water interface: Structural constraints

Effective and controlled use of cross-linking enzymes in structure engineering of food systems depends on characterization of the favorable conditions for enzyme-substrate complex and the limiting factors for the desired modification. In this respect, we analyzed the susceptibility of bovine β-lactoglobulin (BLG) to enzymatic cross-linking by Trichoderma reesei tyrosinase (TrTyr) and transglutaminase (TG). Changes in BLG molecular structure were determined at pH 6.8, 7.5 and 9.0 before and after high-temperature heat treatment. The conformational change was linked to efficiency of protein cross-linking. BLG was not susceptible to TrTyr without heat treatment. TG, however, induced inter-molecular cross-links at pH 7.5 and 9.0. After the heat treatments, BLG molecules adopted a molten-globule-like conformation. Both of the enzymes were able to form inter-molecular cross-links between heat-denatured BLG molecules. Electrophoretic mobility and broadness of the oligomer bands created by both enzymes on SDS-PAGE gels showed differences which were linked to the availability and number of target amino acid residues. Evidence for intra-molecular cross-linking was obtained. Once adsorbed to air/water interface, BLG formed a viscoelastic surface film which was characterized by surface shear rheology. Application of cross-linking enzymes under a dense layer of BLG molecules at the interface led to decreasing G′ with time. Intra-molecular links were most probably favored against inter-molecular on packed BLG layer leading to constrained molecules. Results in general emphasize the importance of structural and colloidal aspects of protein molecules in controlling inter/intra-molecular bond formation by cross-linking enzymes.     

Treatment of high‐fat‐containing dairy wastewater in a sequential UASBR system: influence of recycle

BACKGROUND: Raw cheese whey originating from white cheese production results in a strong and complex wastewater excessively rich in organic matter (chemical oxygen demand, COD = 28–65 g L^?1), fatty matter (14–24.5 g L^?1) and acidity (3.9–6.1 g L^?1). It was treated in a three‐stage configuration consisting of a pre‐acidification (PA) tank and sequential upflow anaerobic sludge bed reactors (UASBRs) at 2.8–7 g COD L^?1 day^?1 organic loading rates, during which the effects of effluent recycling at low rates and promoted SRB activity were investigated. Acidification, volatile fatty acids (VFA), COD and fatty matter removal and volatile solids were monitored throughout the system during the study. RESULTS: Recycling of the effluent promoted VFA and COD removal as well as pH stability in both stages of the UASBRs and the effluent where high alkalinity levels were recovered reducing alkali requirement to 0.05 g OH g^?1 COD_applied. Higher removal rates of 71–100 and 50–92% for VFA and COD were obtained by use of recycling. Fatty matter was removed at 63–89% throughout the study. Volatile solids build‐up was significant in the inlet zones of the UASBRs. CONCLUSIONS: The system produced efficient acidification in the PA tank, balanced pH levels and an effluent high in alkalinity and BOD/COD ratio. Efficient VFA removal and solids immobilization was obtained in both stages up to the highest loading rate. Recycling improved the system performance under high fatty matter loading conditions. A major advantage of the sequential system was that the second stage UASBR compensated for reduced performance in the first stage. Copyright © 2010 Society of Chemical Industry     

Bacterial sensors based on chitosan matrices

Bacterial cells were entrapped together with chitosan matrix onto the surface of graphite electrode to form microbial biosensors. Two types of bacterial sensors were constructed by using Pseudomonas fluorescens (Pseudomonas putida DSM 6521) and P. putida DSM 50026 cells as the biological components and the measurements were based on the respiratory activity of the cells. Carbon nanotube (CNT)-modified chitosan membrane was also prepared to test nanoparticle effect on the efficiency of biosensor performances. As well as the response characteristics, stabilities and substrate specificities were investigated. Data were given as the comparison of CNT-modified and -unmodified systems.     

Investigation of structural properties of clinoptilolite rich zeolites in simulated digestion conditions and their cytotoxicity against Caco-2 cells in vitro

The use of the clinoptilolite rich natural zeolites in biomedical applications such as in anticancer therapy, drug or drug support systems and as nutritive supplement is highly dependent on their behavior in digestive conditions. Aim of this study is to investigate structural stability of clinoptilolite rich natural zeolites in simulated digestion conditions and their interactions with digestive media and with Caco-2 (human colon adenocarcinoma) cells. X-ray Diffraction (XRD), Fourier Transform InfraRed (FTIR), Scanning Electron Microscopy (SEM) and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) analyses of the clinoptilolite rich zeolite samples showed that zeolites preserved their structural stabilities during in vitro digestion. Slight interactions were detected in UV measurements of the digestive liquid media and FTIR spectra of the intestinal digested media powders. SEM results implied that zeolites might have a role in the aggregation of the digestive enzymes. Cytotoxicity test using colon cancer cells showed that clinoptilolite rich natural zeolites have cytotoxic effect against Caco-2 cells and cytotoxicity did not significantly change with respect to simulated digestion process.     

Organisational resilience and relational dynamics in triadic networks: a multiple case analysis

This study aims to analyse resilience and relational dynamics (competitive, cooperative and co-opetitive) within a triadic buyer–supplier–supplier context. Our central goal is to show how a buyer’s supplier–supplier relational behaviour leads to and shapes resilience of this triad. We utilised a multiple-design case approach and selected eight buyers and their suppliers from the textile industry in Turkey. By analysing a triadic context from another industry, we conducted validation analyses. Our findings showed a pattern of relationship between the resilience and the relational dynamics of a triad. Built on theory and insights from the cases, we proposed three propositions. We argued that when co-opetition prevails in a triadic context of relations, the triad resilience level is highest. In competitive relational settings the triad resilience level is lowest, and when the relational dynamics are cooperative, the triad resilience level is moderate. This study is the first to introduce and discuss organisational resilience at triadic level. Furthermore, to our knowledge, our insights from cases are among the first attempts to link three types of supplier–supplier relational dynamics to triad resilience via the use of a multiple-design case approach. Therefore, our contributions are likely to extend the organisational resilience and buyer–supplier–supplier relations research.     

Biosensing Applications of Modified Core–Shell Magnetic Nanoparticles

Fe₃O₄ magnetic nanoparticles (MNPs) were synthesized and silanized to form a core–shell (Fe₃O₄–SiO₂) structure. Afterwards, surface modification with amino silane was carried out to produce amino groups on the MNPs for the biomolecule immobilization. In order to test the performance of amino functional MNPs as immobilization platform in biosensing applications, glucose oxidase was immobilized on the surface via glutaraldehyde. Obtained Bio-MNPs were then fixed onto the carbon paste electrode by the aid of magnetic force and used as the working electrode during the amperometric measurements at −0.7 V versus Ag/AgCl. After optimization of some parameters affecting the biosensor performance, analytical characterization was carried out. Linearity was found in the range of 0.25–2.0 mM glucose and defined by the equation of y = 8.366x + 1.819, (R ² = 0.996). Proposed biosensor was then applied for the glucose analysis in various beverages. Finally, data were compared with a commercial enzyme assay kit based on spectrophotometric Trinder reaction as a reference method.     

Digestibility and allergenicity assessment of enzymatically crosslinked β‐casein

Crosslinking enzymes are frequently used in bioprocessing of dairy products. The aim of this study was to examine the effects of enzymatic crosslinking on IgE binding, allergenicity and digestion stability of β‐casein (CN). β‐CN was crosslinked by transglutaminase, tyrosinase, mushroom tyrosinase/caffeic acid and laccase/caffeic acid. The IgE binding to β‐CN was compared in vitro by CAP inhibition assay, ELISA inhibition as well as ex vivo by basophil activation assay. Crosslinked CNs were digested by simulated gastric fluid for 15 and 60 min and obtained digests analyzed for their ability to inhibit IgE binding by CAP inhibition assay and SDS‐PAGE. The ability of crosslinked CNs to activate basophils was significantly reduced in seven patients in the case of CN crosslinked by laccase and moderately reduced in the case of tyrosinase/caffeic acid crosslinked CN (in two cow's milk allergy patients tested with different allergen concentrations). The response to various crosslinked CNs differed individually among patients' sera tested by ELISA inhibition assay. The presence of caffeic acid hampered digestion by pepsin, and this effect was most pronounced for the tyrosinase/caffeic acid crosslinked CN. The laccase/caffeic acid and mushroom tyrosinase/caffeic acid had the highest potential in mitigating IgE binding and allergenicity of the β‐CN out of all investigated enzymes. The presence of a small phenolic compound also increased digestion stability of β‐CN.