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The research in biopolymer-based superabsorbents is gaining importance in the green chemistry field thanks to their environmentally friendly properties. In this study, a biopolymer-based superabsorbent made of calcium ion crosslinked alginate/carboxymethyl cellulose composite was prepared by a new quasi-cryogelation process, where the complete ionic gelation takes place before the freezing step, in contrast to the conventional cryogelation technique in which gelation occurs under semi-frozen conditions. Thanks to the facile quasi-cryogelation method, the morphology of the gels changed and a significant increase in water absorption properties has been achieved. The swelling properties of the material were investigated in distilled water and different physiological fluids. Results show that the proposed material shows good water absorption property where a water absorption of 2343% was reached and even after five cycles this value was 1200%. As a result, this study reports a biopolymer-based sustainable superabsorbent which is appropriate for various applications such as the removal of pollutants from water or diaper production. [ABSTRACT FROM AUTHOR]

In this article, chemistry research in 51 different European countries between years 2006 and 2016 was studied using statistical methods. This study consists of two parts: In the first part, different economical, institutional and citation parameters were correlated with the number of publications, citations and chemical industry numbers using principal components analysis and hierarchical cluster analysis. The results of the first part indicated that economical and geographical parameters directly affect the chemistry research outcome. In the second part, research in branches of chemistry and related disciplines such as analytical chemistry, polymer science and physical chemistry were analysed using principal components analysis and hierarchical cluster analysis for each country. Publication data were collected as the number of chemistry publications (in Science Citation Index–Expanded (SCI-E)) between years 2006 and 2016 in different chemistry subdisciplines and related scientific areas. Results of the second part of the study produced geographical and economical clusters of countries, interestingly, without addition of any geographical data. [ABSTRACT FROM AUTHOR]

The movement of particles in a capillary electrophoretic system under electroosmotic flow was modeled using Monte Carlo simulation with the Metropolis algorithm. Two different cases with repulsive and attractive interactions between molecules were taken into consideration. Simulation was done using a spin-like system, where the interactions between the nearest and second closest neighbors were considered in two separate steps of the modeling study. A total of 20 different cases with different rates of interactions for both repulsive and attractive interactions were modeled. The movement of the particles through the capillary is defined as current. At a low interaction level between molecules, a regular electroosmotic flow is obtained; on the other hand, with increasing interactions between molecules, the current shows a phase transition behavior. The results also show that a modular electroosmotic flow can be obtained for separations by tuning the ratio between molecular interactions and electric field strength. [ABSTRACT FROM AUTHOR]

The ongoing COVID-19 pandemic is being responded with various methods, applying vaccines, experimental treatment options, total lockdowns or partial curfews. Weekend curfews are among the methods for reducing the number of infected persons, and this method is practically applied in some countries such as Turkey. In this study, the effect of weekend curfews on reducing the spread of a contagious disease, such as COVID-19, is modeled using a Monte Carlo algorithm with a hybrid lattice model. In the simulation setup, a fictional country with three towns and 26,610 citizens were used as a model. Results indicate that applying a weekend curfew reduces the ratio of ill cases from 0.23 to 0.15. The results also show that applying personal precautions such as social distancing is important for reducing the number of cases and deaths. If the probability of disease spread can be reduced to 0.1, in that case, the death ratio can be minimized down to 0. [ABSTRACT FROM AUTHOR]

Since COVID-19 pandemic has been continuously rising and spreading, several original contributions and review articles on COVID-19 started to appear in the literature. The review articles are mainly focus on the current status of the pandemic along with current status of the corona diagnosis and treatment process. Due to some disadvantages of the currently used methods, the improvement on the novel promising diagnosis and treatment methods of corona virus is very important issue. In this review, after briefly discussing the status of current diagnosis and treatment methods, we present to the scientific community, novel promising methods in the diagnosis and treatment of COVID-19. As with other novel approaches, first, the diagnosis potential of mass spectroscopy and optical spectroscopic methods such as UV/visible, infrared, and Raman spectroscopy coupled with chemometrics will be discussed for the corona virus infected samples based on the relevant literature. In vibrational spectroscopy studies, due to complexity of the data, multivariate analysis methods are also applied to data. The application of multivariate analysis tools that can be used to extract useful information from the data for diagnostic and characterisation purposes is also included in this review. The reviewed methods include hierarchical cluster analysis, principal component analysis, linear and quadratic discriminant analysis, support vector machine algorithm, and one form of neural networks namely deep learning method. Second, novel treatment methods such as photodynamic therapy and the use of nanoparticles in the in-corona virus therapy will be discussed. Finally, the advantages of novel promising diagnosis and treatment methods in COVID-19, over standard methods will be discussed. One of the main aims of this paper is to encourage the scientific community to explore the potential of this novel tools for their use in corona virus characterization, diagnosis, and treatment. [ABSTRACT FROM AUTHOR]

Turkey has a wide variety of honey products and most of the honeys are endemic. There are many endemic honey samples in Anatolia that have not been investigated yet. Since natural honey has special benefits due to its many bioactive ingredients, it is still a challenge to classify and characterize different honey samples. In this study, an endemic and rare honey sample from the mountainous and almost uninhabited region of Tuzluca, Iğdır is reported. Honey sample is characterized by the means of antioxidant and antidiabetic capacities, nitrite and nitrate content, fructose/glucose ratio. Results indicate that the reported honey sample has unique characteristics. [ABSTRACT FROM AUTHOR]

ABSTRACT Alginate and chitosan are among the most common biopolyelectrolytes. Surfactants can be included in alginate and chitosan formulations in order to improve their physical and functional properties. In the present study, the effect of the anionic surfactant sodium dodecyl sulfate (SDS) on alginate-chitosan polyelectrolyte multilayer (PEM) films is reported for the first time. Layer-by-layer deposition technique was employed to prepare the PEM samples and the samples were characterized by ellipsometry, X-ray reflectivity, atomic force microscopy, and quartz crystal microbalance with dissipation. Incorporation of SDS into PEM formulations increased the film thickness and an increased adsorption behavior between alginate and chitosan layers are observed. Since the concentration of SDS was below its critical micelle concentration, no micelle formation was expected and hydrophobic-hydrophobic interaction between alginate and SDS might be the main reason. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1798-1803 [ABSTRACT FROM AUTHOR]

Wound dressings require good antiseptic properties, mechanical strength and, more trustably, natural material ingredients. Antimicrobial properties of cerium ions and chitosan are known and alginate based wound dressings are commercially available. In this study, the advantages of these materials were combined and alginate films were crosslinked with cerium(III) solution and chitosan added cerium(III) solution. Films were characterized by Fourier transform infrared spectroscopy (FTIR), light transmittance, scanning electron microscopy (SEM), swelling experiments, water vapor transmittance tests, and mechanical stretching tests. The antibacterial and physical properties of the films were compared with those of conventional calcium alginate films. Both cerium ion crosslinked and cerium ion-chitosan crosslinked alginate films gained antibacterial activity against Gram-negative ( Escherichia coli ) and Gram-positive ( Staphylococcus aureus ) bacteria. Cerium alginate-chitosan films showed high resistance to being deformed elastically. Results show that cerium alginate-chitosan films can be flexible, ultraviolet-protecting, and antibacterial wound dressings. [ABSTRACT FROM AUTHOR]

The purpose of this study was to characterize the Anatolian honey-bee collected pollens according to their sugar, organic acid, mineral, total phenolic contents, and antioxidant activities. Individual organic acids and sugar contents of pollens were determined by capillary electrophoresis. Fructose (F) and glucose (G) were the major sugars. Bee pollen samples contained very diverse organic acids. Gluconic acid was the major organic acid (5.9–32 g/kg) in all the pollen samples. The second highest organic acid content belonged to lactic acid, ranging from 0.72 to 1.2 g/kg. Fourteen elements were determined in each pollen sample by inductively coupled plasma-mass spectrometry (ICP-MS). The Folin-Ciocalteu method was applied for the total phenolic contents of the pollens. The antioxidant activities were evaluated using 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging activity. Principal component analysis (PCA) was applied to analyze results in order to classify the bee pollens from different botanical origins and regions. [ABSTRACT FROM AUTHOR]

SiO 2 glasses doped with ZnSe quantum dots and Nd 3+ ions with compositions of (1% ZnSe–99% SiO 2 ), (2% ZnSe–98% SiO 2 ) and (2% ZnSe–97% SiO 2 –1% Nd 3+ ) were synthesized by sol-gel method and then annealed at 683 K and 873 K for one hour. X-Ray diffraction (XRD) technique was used to identify the crystalline phases of ZnSe quantum dots. It was observed that 0–1 mol% of Nd 2 O 3 addition produced single phase structure in XRD. The average crystallite sizes of ZnSe quantum dots were determined using Scherrer's equation and the FW 1 5 / 4 5 M method. The size of the nanoparticles was found to be in the range of 4–10 nm. It was shown that the presence of Nd 3+ ions led to smaller quantum dot sizes and a narrow size distribution. [ABSTRACT FROM AUTHOR]

This paper addresses the controlled variation of the mechanical properties of alginate gel beads by changing the alginate concentration or by adding different surfactants or cross-linking cations. Alginate beads containing nonionic Brij 35 or anionic sodium dodecyl sulfate (SDS) surfactants were prepared with two different types of cations (Ca 2+ , Ba 2+ ) as crosslinkers. Compression measurements were performed to investigate the effect of the surfactant and cation types and their concentrations on the Young’s modulus of alginate beads. The Young’s modulus was determined by using Hertz theory. For all types of alginate gel beads the Young’s modulus showed an increasing value for increasing alginate contents. Addition of the anionic surfactant SDS increases the Young’s modulus of the alginate beads while the addition of non-ionic surfactant Brij 35 leads to a decrease in Young’s modulus. This opposite behavior is related to the contrary effect of both surfactants on the charge of the alginate beads. When Ba 2+ ions were used as crosslinker cation, the Young’s modulus of the beads with the surfactant SDS was found to be approximately two times higher than the modulus of beads with the surfactant Brij 35. An ion specific effect was found for the crosslinking ability of divalent cations. [ABSTRACT FROM AUTHOR]

Nowadays, dyes constitute a large part of pollutants and have long been used in dyeing, paper and pulp, textiles, plastics, leather, cosmetics, and food industries. Among the conventional dye removal techniques, adsorption is prominent. Research challenges are on developing low-cost, biodegradable and efficient adsorbents. This study investigates polysaccharide–clay composite beads for the removal of methylene blue dye. Alginate–montmorillonite composite beads were prepared and then a novel cryogelation-like strategy was developed by deep-freezing the alginate beads at − 21 °C. This process changed the morphology of beads and improved surface area and adsorption capacity. The results of the batch adsorption experiments were modeled using isothermal, kinetic, and thermodynamic models. It is found that the adsorption is favorable and follows physical mechanism, with an endothermic process up to 40 °C. The prepared composite beads are candidates for effective adsorbents for the dye removal. [ABSTRACT FROM AUTHOR]

Our aim is the characterization of Anatolian monofloral and honeydew honeys according to their mineral, vitamin B2, total phenolic contents and antioxidant activities. Five main elements (Ca, K, Fe, Cu, and Mn) were determined in 20 honey samples by inductively coupled plasma – optical emission spectrometry (ICP-OES). The vitamin B2 contents of honey samples were determined by the capillary electrophoresis method coupled with a sensitive laser induced fluorescence (LIF) detector. The total phenolic contents were analyzed with Folin–Ciocalteu's method. Two comparative antioxidant assays, namely cupric reducing antioxidant capacity assay (CUPRAC) and ABTS radical scavenging assay, were applied to detect the antioxidant power of honeys. Heather honeys were distinguished from others with significantly high vitamin B2 and iron contents. Considerably higher antioxidant capacities and Mn contents were observed for oak and chestnut honeys. Principal components analysis was applied to the analysis result in order to classify the honeys from different botanical origins. [ABSTRACT FROM AUTHOR]

This work describes the in vitro release of a small drug, riboflavin, from novel calcium and barium crosslinked alginate–montmorillonite composite beads via oral route. Effect of crosslinking cation, concentration of montmorillonite and media on encapsulation efficiencies, and release profiles of riboflavin were studied. Beads were characterized using gravimetric swelling ability study, Fourier transform infrared spectroscopy, and scanning electron microscopy. Results indicate that addition of montmorillonite increases the encapsulation efficiencies and slows down the release rates significantly. [ABSTRACT FROM PUBLISHER]

Hybrid hydrogels are a new class of composite materials. Polyacrylamide (PAAm) hydrogels are mainly produced by free radical crosslinking copolymerization (FCC) of AAm in the presence of N, N′-methylene bis (acrylamide) (BIS) as the crosslinker. Pyranine doped PAAm-poly (N-vinyl pyrrolidone) (PVP) composite were prepared with different amounts of PVP varying in the range between 0.0015 and 0.1 gr. It was observed that pyranine molecules as a fluoroprobe bind to AAm and PVP chains upon the initiation of the polymerization, causing the fluorescence spectra of the bonded pyranines shift to the shorter wavelengths. The sol-gel phase transition and its universality were monitored and tested as a function of PVP contents. Observations around the critical point show that the gel fraction exponent, β, agreed with the percolation result for below 0.025 gr PVP contents. However, classical result was observed above 0.0125 gr PVP content. [ABSTRACT FROM AUTHOR]

Spherical alginate beads were prepared by ionotropic gelation of sodium alginate through the use of calcium ions. Pyranine (Py) was added to the alginate solution as a small molecule probe for fluorescence studies. Desorption of Py in water from the alginate beads cross-linked with calcium ions was studied by using the steady state fluorescence technique. The fluorescence emission intensity (I) from Py was monitored during the desorption process at 512 nm using the time drive mode of the spectrofluorometer. The increase in I was attributed to Py release from the beads. The Fickian diffusion model was used to calculate the desorption coefficients, D,which were found to be increased up to 3% (w/v) CaCl2concentration in the beads, and then decreased with a further increase of CaCl2content. On the other hand, the encapsulation efficiency of Py in the calcium alginate beads presented the reverse behavior compared to D. It was observed that, when the content of CaCl2was increased, the incubation time, t0,for the start of desorption increased. [ABSTRACT FROM PUBLISHER]

In this study, spherical alginate beads containing pyranine ( P) as a fluorescence probe were prepared by ionotropic gelation of a sodium alginate solution. The steady state fluorescence technique was used to study pyranine release from the alginate beads crosslinked with calcium, barium and aluminum ions, respectively. The slow release of P was observed with the time drive mode of the spectrophotometer at 512 nm. Fluorescence emission intensity ( I) from P was monitored during the release process, and the encapsulation efficiency (EE) of pyranine from the alginate beads was calculated. The Fickian Diffusion model was used to measure the release coefficients, D. It was seen that the slow release coefficients of pyranine from the alginate beads crosslinked with Ca, Ba, and Al ions increased in the following order: D (Al)> D (Ca)> D (Ba). In contrast, the initial amount of pyranine and EE into the beads showed the reverse behavior. [ABSTRACT FROM AUTHOR]

Abstract: Novel pH sensitive alginate–protein–clay composite beads were investigated for the in vitro oral delivery of the model protein, bovine serum albumin (BSA). X-ray diffraction (XRD) results revealed that BSA enter between layers of montmorillonite (MMT) by expanding interlayer distance and finally an exfoliated structure forms in the alginate hydrogel. MMT incorporation increases protein entrapment efficiency to 78%, compared to 40% of conventional alginate beads. The release ratio of BSA from composite beads is 9–13% depending on MMT contents after around a 2h stay in gastric fluid. More importantly, no BSA release is detected until 60–90min after the first contact time of beads with gastric solution. The presence of clay in alginate beads prevents burst release in higher pH of intestine by slowing release rate of BSA to 45–55% within around 9h, resulting in a potential matrix for intestinal release of protein drugs. [Copyright &y& Elsevier]

The aqueous adsorption of a fluorescent dye (pyranine) onto crosslinked chitosan-graphene oxide composite films was studied. In situ fluorescence monitoring technique is introduced as easy and fast experimental technique to select optimal adsorbent conditions. The effect of ionic crosslinker on adsorption was studied with sodium tripolyphosphate, trisodium citrate, and sodium sulfate, respectively. Among the crosslinkers, it was realized that sodium sulfate crosslinked films showed a greater adsorption rate for pyranine than the other two types of crosslinked films. Recently, graphene oxide is of interest as a filler compound for many biopolymer applications due to its favorable thermal, mechanical and surficial properties. In the present study, graphene oxide incorporation increased adsorption rate of the dye and the mechanical strength of ionically crosslinked chitosan films. The adsorption behavior of the adsorbent was explained by a kinetic model. Samples were characterized using scanning electron microscopy, thermogravimetric analysis, swelling experiments and tensile testing method. [ABSTRACT FROM AUTHOR]

Background/aim: Intercity travel is one of the most important parameters for combating a pandemic. The ongoing COVID-19 pandemic has resulted in different computational studies involving intercity connections. In this study, the effects of intercity connections during an epidemic such as COVID-19 are evaluated using a new network model. Materials and methods: This model considers the actual geographic neighborhood and population density data. This new model is applied to actual Turkish data by means of provincial connections and populations. A Monte Carlo algorithm with a hybrid lattice model is applied to a lattice with 8802 data points. Results: Around Monte Carlo step 70, the number of active cases in Türkiye reaches up to 8.0% of the total population, which is followed by a second wave at around Monte Carlo step 100. The number of active cases vanishes around Monte Carlo step 160. Starting with İstanbul, the epidemic quickly expands between steps 60 and 100. Simulation results fit the actual mortality data in Türkiye. Conclusion: This model is quantitatively very efficient in modeling real-world COVID-19 epidemic data based on populations and geographical intercity connections, by means of estimating the number of deaths, disease spread, and epidemic termination. [ABSTRACT FROM AUTHOR]

Abstract In this study, 14 Turkish Salvia species, 12 of which are endemic, were characterized based on their vitamin B2, mineral, total phenolic contents, and antioxidant activities. Determination of vitamin B2 in Salvia species was achieved by a fast and sensitive capillary electrophoresis technique using a laser induced fluorescence (LIF) detector. All samples contain vitamin B2 ranging from 0.165 to 1.19 mg/100 g. Fifteen elements (Ca, K, Na, Mg, Fe, Mn, Zn, Li, Cu, Co, Al, V, Sr, Sn, and Ni) were determined in each Salvia sample by inductively coupled plasma-mass spectrometry (ICP-MS). Total phenolic contents of the Salvia samples, ranging from 11.8 to 119 mg gallic acid equivalents (GAE)/g, were determined using the Folin-Ciocalteu's method. The antioxidant activities were evaluated by 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power assay (FRAP). Analysis data were evaluated by principal component analysis (PCA) and differentiation among Salvia species was shown. Highlights • Fourteen Salvia species were collected from different regions of Turkey. • Vitamin B2 content in Salvia species is firstly reported in this study. • Mineral contents, antioxidant activities, and total phenolics were evaluated. • Principal component analysis was applied to the results to classify the samples. [ABSTRACT FROM AUTHOR]

• Nanoceria doped chitosan/cellulose acetate films are reported for the first time. • Films exhibit good physical and mechanical properties. • Good antibacterial characteristics of the films are obtained. Novel chitosan and cellulose acetate polymer composites with nanosized cerium oxide were prepared as potential wound dressing materials. Chitosan and cellulose acetate are natural polymer derivatives with biocompatible properties. Both polymers can be dissolved in formic acid. The polymer composite was formed by solvent-casting method. The formed films were not soluble in water. In order to improve antibacterial, thermal, and mechanical properties of the composite material, films were loaded with nanosized cerium oxide. Films were characterized with thermogravimetric, scanning electron microscopy with energy-dispersive X-ray spectroscopy, mechanical, ultraviolet-visible light transmittance, water solubility, pH, moisture content, water vapor transmission rate, swelling, and antibacterial tests. The physical properties and antibacterial characteristics of the films are promising for further research as a potential wound covering material. [ABSTRACT FROM AUTHOR]