Anions In Solution Research Articles

Extreme Toughening of Conductive Hydrogels Through Synergistic Effects of Mineralization, Salting-Out, and Ion Coordination Induced by Multivalent Anions.

Developing conductive hydrogels with both high strength and fracture toughness for diverse applications remains a significant challenge. In this work, an efficient toughening strategy is presented that exploits the multiple enhancement effects of anions through a synergistic combination of mineralization, salting-out, and ion coordination. The approach centers on a hydrogel system comprising two polymers and a cation that is highly responsive to anions. Specifically, polyvinyl alcohol (PVA) and chitosan quaternary ammonium (HACC) are used, as PVA benefits from salting-out effects and HACC undergoes ion coordination with multivalent anions. After just 1 h of immersion in an anionic solution, the hydrogel undergoes a dramatic improvement in mechanical properties, increasing by more than three orders of magnitude. The optimized hydrogel achieves high strength (26 MPa), a high Young's modulus (45 MPa), and remarkable fracture toughness (67.3 kJ m-2), representing enhancements of 860, 3200, and 1200 times, respectively, compared to its initial state. This breakthrough overcomes the typical trade-off between stiffness and toughness. Additionally, the ionic conductivity of the hydrogel enables reliable strain sensing and supports the development of durable supercapacitors. This work presents a simple and effective pathway for developing hydrogels with exceptional strength, toughness, and conductivity.

Nanofiltration Membranes Containing a Metal-Polyphenol Network Layer: Using Casting Solution pH as a Tool to Tailor the Separation Performance.

Thin-film composite (TFC) membranes containing metal-polyphenol network (MPN) selective layers were fabricated using a supramolecular self-assembly between tannic acid (TA) and ferric ion (Fe3+). The TA-Fe3+ thin film was coated on a porous polyacrylonitrile support using aqueous solutions of TA and FeCl3 via a layer-by-layer deposition technique. The pH of the TA solution was used as a tool to alter the membrane characteristics. The surface porosity and water contact angle of the fabricated membranes gradually decreased as the pH of TA casting solutions was increased from 3 to 8.5 for both single-layered and double-layered TA-Fe3+ TFC membranes. This allowed us to tune the water permeance and the retentions of water-soluble neutral and anionic molecules by the MPN membranes by varying the pH of the casting solution. It has been shown that the water permeance decreased from 184 to 156 L·m-2·h-1·bar-1 for single TA-Fe3+ layer coated membranes when the pH was increased from 3 to 8.5, while it declined from 51 to 17 for the double TA-Fe3+ layer. Anionic solutes in aqueous solutions were highly retained compared to neutral components as the TFC membranes had a negative surface charge. Retentions of 95 and 90% were achieved for naphthol green B and orange II dyes by a double-layered M4 membrane fabricated at pH 8.5, while only 13% retention was found for the neutral riboflavin. The neutral dye riboflavin permeated 30.8 times higher than the anionic dye naphthol green B during a mixed dye filtration test through the TFC membrane prepared by using a TA solution of pH 8.5. To the best of our knowledge, this is the highest selectivity of a neutral/anionic dye pair so far reported for a TFC membrane having an MPN selective layer. Moreover, fouling tests have demonstrated that the MPN separation layers exhibit robust stability and adequate antifouling performance with a flux recovery ratio as high as 82%.

Inhibition sensitivity of invitro firefly bioluminescence quantum yields to Zn2+ and Cd2+ concentrations in aqueous solutions.

To elucidate the inhibition effects of Zn2+ and Cd2+ on the luciferin-luciferase reaction, we performed quantitative measurements of quantum yields and spectral shapes for invitro firefly bioluminescence in aqueous solutions containing ZnSO4, ZnCl2, CdSO4, and CdCl2 at different concentrations. Particular care was taken toward the equilibrium between metal ions and enzyme proteins, anion difference, solubility, and uncertainty evaluation. The bioluminescence quantum yields decreased almost linearly to the concentration of Zn2+ and Cd2+ below 0.25 mM. No obvious difference was found between the chloride and sulfate anion solutions. We defined inhibition sensitivity as the decrease in relative quantum yield versus the concentration of metal ions, and they were determined to be 1.48 ± 0.13 and 1.13 ± 0.16/mM for Zn2+ and Cd2+, respectively. We estimated the detection limit of inhibition effects as the concentration of metal ions that decrease relative quantum yields by 10%, which were 0.07 mM (4 ppm) and 0.09 mM (10 ppm) for Zn2+ and Cd2+, respectively. The shape of the bioluminescence spectra changed sensitively with the increase in Zn2+ concentrations. The bioluminescence peak energy for 0.10-mM Zn2+ was ~2.2 eV, while that for 0.25-mM Zn2+ was ~2.0 eV. The shape of the spectra changed less sensitively with the increase in Cd2+concentrations, and the peak energy was at ~2.2 eV for Cd2+ concentrations of 0.10 and 0.25 mM.

Solution and Surface Solvation of Nitrate Anions with Iron(III) and Aluminum(III) in Aqueous Environments: A Raman and Vibrational Sum Frequency Generation Study.

Hydrated trivalent metal nitrate salts, Fe(NO3)3·9H2O and Al(NO3)3·9H2O, in both solid and aqueous phases are investigated. Raman and surface-selective vibrational sum frequency generation (SFG) spectroscopy, are used to shed light on ion-ion interactions and hydration in several spectral regions spanning low frequency (440-550 cm-1) to higher frequency modes of nitrate and water (720, 1050, 1250-1450, and 2800-3750 cm-1). These frequencies span the metal-water mode, nitrate in-plane deformation, nitrate symmetric and asymmetric modes, and the OH stretch of condensed phase water molecules. Comparison to NaNO3, and in some cases KNO3, is also shown, providing insight. Splitting and frequency shifts are observed and discussed for both the solid state and solution phase. The Lewis acidity of Fe3+ and Al3+ ions plays a significant role in the observed spectra, in particular for the nitrate asymmetric band splitting and frequency shift. The spectral response from water solvation for iron and aluminum nitrates is nonlinear as compared to linear for sodium nitrate, suggesting significantly different solvation environments that are limited by water hydration capacity at higher concentrations. Moreover, a non-hydrogen bonded OH, dangling OH, from hydrating water molecules is observed spectroscopically for Al and Fe nitrate solutions. Furthermore, aluminum nitrate perturbs the surface water structure more than iron nitrate despite aluminum being a weaker Lewis acid. The surface water structure is thus found to be unique for the Al(NO3)3 solutions as compared to both Fe(NO3)3 and NaNO3, such that surface solvation is more pronounced. This observation exemplifies the nature of the Fe(III) and Al(III) ions and their substantial influence on the surface water structure.

Rac-2-(2′-Ferrocenyl-2′-hydroxy-n-propyl)-1,3-benzothiazole

The synthesis and characterisation (UV-Vis, IR, HRESI-MS, 1H and 13C NMR spectroscopies, electrochemistry) is reported of the novel title material (1: alternatively named rac-1-(2′-benzothiazolyl)-2-ferrocenyl-2-propanol): a rare example of a ferrocenyl-benzothiazole hybrid species. Compound 1 is produced by the low temperature reaction of acetylferrocene (3) with a solution of the methyl anion derived via the deprotonation of 2-methyl-1,3-benzothiazole. The yield of 1 is moderate (34%) after purification and is an air and thermally stable solid under ambient conditions. Attempts to sublime 1, however, result in decomposition with one of the products being identified (NMR) as 3. The spectroscopic features of 1 are presented. Attempts to obtain suitable crystalline material of 1 for a single crystal X-ray diffraction study were unfortunately unsuccessful. Compound 1 also does not form stable coordination complexes with various metal salts (e.g., Ni[2+], Co[2+], etc.) under the conditions tested.

A facile synthesis of a novel polymer-based nanocomposite as colorimetric response sensor for fluoride ion detection in real-life complex mediums

The surface modification of Poly (acrylamide-co-methylenbisacrylamide-co-N-(4-(2-(phenylcarbamothioyl)hydrazineyl)phenyl)methacrylamide) as a sensor (AR) via titanium dioxide as a novel colorimetric nanocomposite sensor with high sensitivity and selectivity for determination of fluoride anion was described. The colorimetric response of the AR has been screened in dimethyl sulfoxide /Water with a volumetric ratio of 7:3 and acetonitrile in separate media with equal amounts of various anions. In the presence of the mentioned anionic solutions, only the solutions containing fluoride ions, made a significant change in color from pale yellow to orange-red via the –NH deprotonation mechanism, which could be detected with the naked eye. The Box-Behnken design, response surface methodology through UV-Vis spectroscopy techniques in various pH and temperatures and reaction times were tested to optimize the AR conditions. Also, a lateral flow assay test of the synthesized AR detected fluoride ions in real-life samples, including water, contrary to different sources such as toothpaste and mouthwash. Furthermore, according to the World Health Organization report on fluoride ion toxicity in water, the detection limit of the AR was lower than of the declared level.

Regional use of extracellular microvesicles of mesenchymal stromal cells in acute necrotizing pancreatitis in an experiment

Background. The significance of the problem of treatment of acute pancreatitis is due to an increase in the incidence with an increase in the number of necrotizing forms, accompanied by a high incidence of severe complications and high mortality.Objective. To identify the impact of regionally used extracellular microvesicles of mesenchymal stromal cells on the endogenous intoxication markers in acute necrotizing pancreatitis in the experiment.Material and methods. Acute pancreatitis was induced by the introduction of a 0.3 ml of 5% solution of non-ionic polyethylene glycol octylphenol ether detergent into the caudal part of the rat pancreas. The study was conducted on 42 adult Wistar rats, which were randomly divided into 4 groups. Group I (n=6) included intact animals, Group II (control group) (n=12) included rats with pancreatitis without treatment, Group III (n=12) consisted of rats with pancreatitis treated with analgesia + infusions of 0.9% sodium chloride solution (saline), Group IV (n=12) included rats with pancreatitis treated with analgesia+ saline infusions + regional application of extracellular microvesicles of mesenchymal stromal cells. Cells were obtained from the bone marrow of healthy animals. Microvesicles were obtained by differential centrifugation under sterile conditions. Microvesicles were administered one day after the pancreatitis induction through the catheter installed into the pathologically altered part of the pancreas. The dose of microvesicles was calculated as equivalent to (derived from) 1 million mesenchymal stromal cells. The hematological parameters, markers of the systemic manifestation of the pathological process (alpha-amylase, aspartate aminotransferase, alanine aminotransferase), the endogenous intoxication markers (lipid peroxidation activity, nitric oxide level), the systemic inflammatory response markers (tumor necrosis factor-alpha, interleukin-6) were studied on the 3rd and 7th day from the start of disease modeling.Results. Regional use of extracellular microvesicles of mesenchymal stromal cells in the treatment of acute experimental necrotizing pancreatitis at an early stage helped to normalize the level of blood platelets, reduce enzymeemia, elements of endogenous intoxication (interleukin-6, tumor necrosis factor-alpha), and the nitric oxide level.Conclusion. The early application of extracellular microvesicles of mesenchymal stromal cells in the treatment of acute necrotizing pancreatitis in an experiment has a positive effect on parameters, which are key links of pathogenesis and leading markers of this disease severity.

Impact of different rinsing temperatures on SnS thin films created using the SILAR technique

The (SnS) thin films were prepared by Successive Ionic Layer Adsorption and Reaction (SILAR), a versatile and simple method. The cationic and anionic solutions SnCl2.2H2O and Na2S.9H2O respectively were used as precursor materials, which will be deposited on glass substrates to study the effect of rinsing temperature on the properties of our thin films. The structural, morphological, and optical properties were investigated by using X-ray diffraction, Energy Dispersive X-ray analysis (EDX), Scanning Electron Microscopy (SEM) and spectrophotometer. X-ray Diffraction (XRD) patterns indicated that the deposited SnS thin films have an orthorhombic crystal structure. Uniform deposition of the material over the entire glass substrate was shown by Scanning Electron Microscopy (SEM). The optical band gap energy ranged from 1.5 to 1.82eV for direct transitions and from 0.6 to 0.95eV for indirect transitions.

Effect of Ni Addtion on Electroless Cu for High Density Interconnect PCB Substrate

Introduction Nowadays, high-density interconnect (HDI) printed circuit board (PCB) substrates have been widely applied to high-end electronics to meet the increasing input and output (I/O) density and small footprint area. Micro-via, a tiny structure buried among build-up layers that provide electrical interconnection is a key component in the HDI substrate. However, the preparation of micro-via is facing new challenges. It is not only required that the size of the micro-via scales down to meet the increased interconnect density, but also that the micro-via should withstand severe operating conditions in different scenarios. Therefore, it is of great importance to improve the quality of micro-vias during processing and manufacturing. The micro-via structure is a sandwich structure that is processed by electroless Cu plating and Cu electrolyte plating sequentially, and thus the quality of the electroless Cu layer can significantly affect the reliability of micro-via. In this work, we mainly focused on the electroless Cu plating process and investigated the effect of the electroless Cu deposition speed on the quality of the micro-via structure. SIM and HR-TEM characterizations were employed to investigate the micro-structure inside the electroless Cu layer. Materials and Method In this study, we used the common alkaline ion catalyst method to prepare the electroless Cu layer. The electroless Cu plating and electrolyte Cu plating was conducted on a PCB Resin Coated Copper (RCC) substrate that was cleaned by soft etching in an acid condition. The surface is then pre-dipped in an anionic solution, and palladium ions were adsorbed using an alkaline ion catalyst. The electroless Cu processes adopted in a reaction bath that consists of Cu resource (CuSO4·5H2O), complexing agent (KNaC4H4O6·4H2O) and reductant (HCHO). The whole reaction was conducted in the alkaline condition with a PH of 12.5, and the thickness of the electroless Cu deposition was controlled at around 0.20 µm. NiSO4 is selected as the Ni precursor to alter the Ni concentration in the reation bath. The contents of Ni addition were selected as 50 %, 100 %, 200 % and 300% of a conventional process at a bath temperature of 27 ºC. The thickness of the plated Cu layer was measured by a gravimetric method. Results and discussion TEM observation was used to identify the structure at the interface. Fig. 1 shows the TEM observation of the sample with 50 % and 200 % Ni concentrate. There are some nanovoids found at the interface between the Cu substrate and electroless Cu, which is arguably due to hydrogen generated during electroless Cu plating. The sample with a higher reaction speed has more nanovoids. It can be due to that the higher reaction speed can generate more hydrogen bubbles in the bath that can attach to the electroless Cu layer, leading to nanovoids as shown in Fig. 1. The samples prepared at different bath temperatures are under investigation to illustrate that the reaction speed can significantly affect the Cu electroless layer quality. Conclusions In this work, we investigated the Ni effect in electroless Cu on the RCC substrate. It is found that the higher Ni incorporation can lead to massive nanovoids generation and fine Cu grains in the electroless layer, which is a potential risk for the reliability of the HDI substrate. By reducing the Ni incorporation content, the number of nanovoids can be effectively reduced. Figure 1

(Invited) Electrochemical Processes Drive Membrane-Based Recovery of N and P

We expend a large amount of energy and money on the treatment of municipal and industrial wastewater, relying on redox reactions to transform contaminants (e.g, ammonium, reduced carbon) into other less/non-harmful species (N2/NO3 -, CO2), or on biological accumulation approaches that sequester contaminants into bacteria (e.g., biomass, PO4 -3). In the worst case, these contaminants are simply released into the environment where they cause harm and are lost. Yet, many of these contaminants are actually valuable resources (e.g., NH3, PO4 -3). In an age where environmental sustainability and climate change mitigation are of utmost importance, it makes little sense to invest large amounts of energy into the conversion and elimination of these valuable resources, only to turn around and use fossil fuels to produce more. In addition, the value of these resources is often higher than the value of the treated water, making their recovery an economically-attractive prospect.Here, we discuss our recent work on membrane-based separations of ammonia, phosphate, and volatile fatty acids (VFAs) from different waste streams. Critically, in all cases we achieve separation by leveraging electrochemical reactions and processes. For ammonia recovery, we utilize an electroactive membrane contactor that is used as a cathode – the application of cathodic potentials to the membrane surface increases the local pH at the membrane/water interface, which transforms ammonium to ammonia and enables its effective volatilization and recovery across the membrane. For VFA recovery, we use a composite electroactive membrane that combines electrothermal heating and an electrochemical pH swing to protonate and extract these volatile species from water. Finally, for phosphate separation, we engineer a phosphate-specific pathway through a cation exchange membrane, and use electrodialysis to pull phosphate ions from a mixed anion solution. Together, these approaches can be used to recover valuable products from complex waste streams, such as municipal and industrial wastewater, without the need to rely on bulk pH and temperature modification.

Effect of Anionic Surfactants on the Oil-Water-Rock Interactions by an Improved Washburn Method.

The complex and variable structure of subsurface oil reservoirs as well as the small pore throat size of reservoirs make it extremely important to investigate the effect of oil-water-rock interactions for enhancing oil recovery. In this paper, the powder wettability of oil sand with different polar solvents was investigated using the improved Washburn capillary rise method, and the surface free energy of oil sand was calculated in combination with the OWRK method. In addition, the wettability of anionic surfactants HABS and PS solutions on the surface of oil sand was determined, and it showed that their wetting rates showed different trends after CMC (critical micelle concentration). The C×cosθ value of HABS decreased significantly with increasing concentration, whereas PS showed little changes. This may be related to the aggregate structure formed by HABS on the oil sand surface. Meanwhile, the interfacial free energy between crude oil and oil sand was obtained by crude oil-to-oil sand wetting experiments, and found that the wetting rate of crude oil to oil sand was much lower than that of solvents and surfactants. In combination with the above results and the oil-water interfacial tension (IFT), the oil-water-rock three-phase contact angle and the work of adhesion between the crude oil and the solid were obtained by Young's equation. From the three-phase contact angle results, it can be found that the contact angle values of both HABS and PS are obviously higher than that of the simulated water, and both HABS and PS have the ability to significantly reduce the work of adhesion, which shows a strong ability to strip the oil film on the surface of the solid. The research results of this paper are helpful to understand the oil displacement mechanism of chemical flooding in reservoir pores, which is of great significance for improving oil recovery.

Novel porous hydrogel beads based on amidoxime modified polymer of intrinsic microporosity for efficient cationic dye removal

Due to the high surface area and facile functionalized or modified groups of polymers of intrinsic microporosity, and the hydrophilicity of sodium alginate (SA), a simple strategy was proposed for preparing porous composite hydrogel beads with excellent cationic dye adsorption capacity and selectivity. The porous composite hydrogel beads were prepared by introducing the amidoxime modified polymers of intrinsic microporosity (AOPIM-1) into SA polymer solution and then dropping the mixture into CaCl2 aqueous solution at low temperature for crosslinking. The prepared porous SA/AOPIM-1 hydrogel beads performed excellent adsorption capacity on Rhodamine B (RhB) from aqueous solution and the Langmuir model was suitable for describing the adsorption behavior of RhB on porous SA/AOPIM-1 hydrogel beads. It is surprising that the maximum theoretical adsorption capacity obtained by fitting the Langmuir model was up to 1648.3 mg·g−1. More importantly, porous SA/AOPIM-1 hydrogel beads showed outstanding selective adsorption capacity for cationic dyes in the mixed anionic and cationic dyes solution. Besides, the adsorption capacity of porous SA/AOPIM-1 hydrogel beads could maintain above 80 % of the initial adsorption capacity after 10 adsorption/desorption cycles. The above results indicate that porous SA/AOPIM-1 hydrogel beads can be used as a promising adsorbent with for effective removal of dyes from wastewater treatment.

Synergisms between Surfactants, Polymers, and Alcohols to Improve the Foamability of Mixed Systems

In order to produce detergents with improved performance and good market acceptability, it is crucial to develop formulations with improved foamability and cleaning performance. The use of a delicate balance of surfactants and additives is an appealing strategy to obtain good results and enables a reduction in the amount of chemicals used in formulations. Mixtures of hydrophobically modified linear polymers and surfactants, as well as balanced mixtures with co-surfactants and/or hydrotropes, are the most effective parameters to control foamability and foam stability. In the present study, the effect of the addition of hydrophobically modified linear polymers, nonionic co-surfactants and hydrotropes, and their mixtures to anionic and zwitterionic surfactant aqueous solutions was evaluated. It was found that the presence of the hydrophobically modified polymer (HM-P) prevented the bubbles from bursting, resulting in better stability of the foam formed using zwitterionic surfactant solutions. Also, the surfactant packing was inferred to be relevant to obtaining foamability. Mixtures of surfactants, in the presence of a co-surfactant or hydrotrope led, tendentially, to an increase in the critical packing parameter (CPP), resulting in higher foam volumes and lower surface tension for most of the studied systems. Additionally, it was observed that the good cleaning efficiency of the developed surfactant formulations obtained a higher level of fat solubilization compared to a widely used brand of commercial dishwashing detergent.

Promote or inhibit turbulence drag reduction behavior of surfactant solutions with different micelle structures by certain nanoparticle addition

The micelle structure of surfactant is easy to be destroyed in the flow process resulting in a decrease in its drag reduction (DR) efficiency; therefore, how to strengthen the stability of the micelle structure during the flow process and thus improve the drag reduction efficiency deserves intensive research. In this work, by comparing a variety of nanoparticles, hydrophobic silica nanoparticles were selected as the best additive to enhance the turbulence drag reduction efficiency of surfactant solution with spherical micelle structure. The experimental results also demonstrated that the hydrophobic silica nanoparticles had a reinforcing effect on anionic, cationic, nonionic, and zwitterionic surfactant solutions with the same concentration (dominated by spherical micelles), and the optimal nanoparticle addition concentration and maximum drag reduction rate were obtained. Meanwhile, the effect of silica nanoparticles on the turbulence drag reduction efficiency of surfactant solutions with different micelle structures was evaluated by inducing the surfactant micelle structure change. It was shown that the hydrophobic silica nanoparticles had a strengthening effect on the turbulence drag reduction performance of surfactant solutions with spherical micelle structure, while they had an inhibiting effect on the turbulence drag reduction performance of surfactant solutions with worm-like micelle structure. The change in solution viscoelasticity indicated that the decrease in viscoelasticity was the main reason for the decrease in drag reduction efficiency of surfactant solution with worm-like micelle structure when silica nanoparticles were added. A mechanism for the interaction of hydrophilic/hydrophobic silica nanoparticles with spherical micelles and wormlike micelle structures was finally discussed and proposed.

Oil spill dispersant formulation from Palmitoyl-DEA and methyl ester sulfonate

Surfactants are chemical compounds that can interact with solvents to reduce surface tension. Palmitoyl-Diethanolamide surfactant (Palmitoyl-DEA) and methyl ester sulfonate (MES) can be applied in dispersing oil in seawater as Oil Spill Dispersant (OSD). An OSD formulation derived from a mixture of two surfactant solutions, namely Palmitoyl-DEA and MES, was found. Diethanolamide non-ionic surfactant solution and anionic methyl ester sulfonate surfactant solution in various concentrations were mixed according to their respective ratios at 50℃ for 60 minutes. The OSD product obtained was then analyzed for density, surface tension, and emulsion stability. OSD products at a concentration of 4% MES and 2% DEA with a 2:1 ratio obtained the best analytical results. The OSD product has excellent density, surface tension, and emulsion stability (> 80%). Furthermore, testing of OSD products was carried out for oil pollution in seawater. The results of simulation tests using OSD products for handling petroleum pollution in seawater (15 mL/L) show an excellent ability to disperse oil (> 90%). The oil and OSD dispersed in seawater showed a more significant increase in COD and BOD values.

Synthesis, crystal structures, photochromism and selective luminescence sensing property of Zn/Cd-viologen coordination polymers

Three Zn/Cd-viologen coordination polymers (CPs), namely, {Zn[(bcbpy)0.5(ipa)(H2O)]·H2O}n (1), {Zn[(bcbpy)0.5(ipa)(H2O)0.5]·H2O}n (2), and {Cd[(bcbpy)(SO4)]·2H2O}n (3), have been constructed using aromatic carboxylic acid and viologen-derived ligands, where H2bcbpy·2Cl represents 1,1′-bis((4-carboxyphenyl)-4,4′-bipyridine) dichloride and H2ipa stands for isophthalic acid. All three CPs display photochromic properties, transforming from yellow to dark blue upon irradiation with a xenon lamp. Notably, the photoresponse rates vary among these CPs, with compound 1 showing the fastest photoresponse, followed closely by compounds 2 and 3. Furthermore, CPs 1, 2, and 3 display a unique sensitivity to different concentrations of Cr2O72- anion solutions. When immersed in these solutions, the compounds exhibit varying degrees of fluorescence quenching effects, allowing for the monitoring of even the lowest ion concentrations. Additionally, upon exposure to ammonia vapor, the three compounds undergo a color change from yellow to dark brown, indicating their sensitivity to ammonia vapor.

Application of mesenchymal stem cells in severe acute experimental pancreatitis

Background. The significance of the problem of acute pancreatitis is due to an increase in the incidence with an increase in the number of common forms of pancreatic necrosis, accompanied by a high incidence of severe complications.Aim. To determine the effect of regional application of mesenchymal stromal cells on the systemic manifestations of severe acute experimental pancreatitis.Material and methods. This experimental study was carried out on 42 adults Wistar rats. Acute pancreatitis was induced by administering 0.3 ml of 5% solution of non-ionic polyethylene glycol octylphenol ether detergent into the caudal part of the pancreas. The animals were randomly divided into 4 groups: Group I (n=6) consisting of intact animals, Group II (control group) (n=12) of rats with untreated pancreatitis, Group III (n=12) of rats with pancreatitis treated: anesthesia + infusions of 0.9% sodium chloride solution (saline), and Group IV (n=12) of rats with pancreatitis treated: anesthesia + infusions of saline + regional application of mesenchymal stromal cells. Animals were taken out of the experiment by euthanasia on the 3rd and 7th day. The hematological parameters, markers of systemic manifestation of the pathological process (pancreatic amylase, aspartate aminotransferase, alanine aminotransferase, urea, creatinine), markers of endogenous intoxication (lipid peroxidation activity, nitric oxide level), markers of systemic inflammatory response (C-reactive protein, tumour necrosis factor-alpha, interleukin-6) have been evaluated.Results. The application of mesenchymal stromal cells in the early stages of acute pancreatitis made a favourable effect on the platelet count, the level of glycemia, helped to reduce the content of endogenous intoxication elements (malonic dialdehyde, nitric oxide) and of those of the systemic inflammatory response (interleukin-6, tumor necrosis factor-α, C-reactive protein), which are key links in the pathogenesis of severe acute pancreatitis.Conclusion. Comparison of different treatment regimens for acute experimental pancreatitis has shown that the early use of mesenchymal stromal cells has a systemic positive effect and confirms the therapeutic efficacy of the method in the treatment of this disease.

Metal-Complex Inks for Lower Cost and Improved Passivation for Silicon Photovoltaic Metallization

This contribution introduces the silicon PV community to screen-printable metal-complex inks that potentially will reduce Ag usage in Si PV metallization to one-quarter and costs to one-third that of traditional particle-based pastes while also improving passivation. Metal-complex inks are formulated using a Tollen’s reaction to produce inks with a high percentage of diamminesilver (I) cations (22 wt %) in a solution of acetate and formate anions. When printed and dried, labile ammonia ligands evaporate, leaving behind silver cations which, when reduced by formate anions and acetic acid, plate out silver and silver acetate. When annealed to just 300 °C a dense metallic silver film forms with excellent conductivity, and adhesion to silicon. When compared to traditional particle-based screen-printing pastes, the metal-complex inks are much denser, have higher conductivity, use less Ag, and are a fraction of the cost. Importantly, the inks anneal from 90 – 450 °C allowing for improved passivation schemes compared with fired SiNx. This contribution highlights first experiments on the improved passivation of metallized poly-Si/SiO2 passivated contacts using metal-complex Ag inks.

Investigation on fluorescent sensing properties of Cd(II)-coordination polymers synthesized by nitrogen-containing carboxylic acid ligand

In this study, two-dimensional (2D) cadmium-based coordination polymer (CP) (Cd-1, [Cd4L8]n) and one-dimensional (1D) cadmium-based CP (Cd-2, [CdL(H2O)(NO3)·H2O]n) have been obtained by mixing 1-(4-benzoic acid)-3-(pyrazinyl)-1H-1,2,4-triazole (HL) as organic ligand and CdCO3 as a source of metal ions in hydrothermal/solvent-thermal reaction. The structures and properties of two examples of Cd(II) CPs were characterized and analyzed. The results from infrared spectroscopy, thermogravimetric analysis, and X-ray single-crystal diffraction analysis indicated that the CPs have a stable framework structure and better thermal stability. In addition, in the study of fluorescence properties, two Cd(II)-CPs were found to have high sensitivity to the specific recognition of Fe3+, CrO42− and Cr2O72− ions in metal nitrate and anionic aqueous solutions, and the stability and recyclability of which were further demonstrated through cycling tests, which are expected to be used for the development of the new Cd(II)-CPs and to be an excellent fluorescent probe material.

Optimize the parameters for the synthesis by the ionic gelation technique, purification, and freeze-drying of chitosan-sodium tripolyphosphate nanoparticles for biomedical purposes

BackgroundPolymeric nanoparticles can be used for wound closure and therapeutic compound delivery, among other biomedical applications. Although there are several nanoparticle obtention methods, it is crucial to know the adequate parameters to achieve better results. Therefore, the objective of this study was to optimize the parameters for the synthesis, purification, and freeze-drying of chitosan nanoparticles. We evaluated the conditions of agitation speed, anion addition time, solution pH, and chitosan and sodium tripolyphosphate concentration.ResultsChitosan nanoparticles presented an average particle size of 172.8 ± 3.937 nm, PDI of 0.166 ± 0.008, and zeta potential of 25.00 ± 0.79 mV, at the concentration of 0.1% sodium tripolyphosphate and chitosan (pH 5.5), with a dripping time of 2 min at 500 rpm. The most representative factor during nanoparticle fabrication was the pH of the chitosan solution, generating significant changes in particle size and polydispersity index. The observed behavior is attributed to the possible excess of sodium tripolyphosphate during synthesis. We added the surfactants poloxamer 188 and polysorbate 80 to evaluate the stability improvement during purification (centrifugation or dialysis). These surfactants decreased coalescence between nanoparticles, especially during purification. The centrifugation increased the zeta potential to 40.8–56.2 mV values, while the dialyzed samples led to smaller particle sizes (152–184 nm). Finally, freeze-drying of the chitosan nanoparticles proceeded using two cryoprotectants, trehalose and sucrose. Both adequately protected the system during the process, and the sugar concentration depended on the purification process.ConclusionsIn Conclusion, we must consider each surfactant's benefits in formulations for selecting the most suitable. Also, it is necessary to do more studies with the molecule to load. At the same time, the use of sucrose and trehalose generates adequate protection against the freeze-drying process, even at a 5% w/v concentration. However, adjusting the percentage concentration by weight must be made to work with the CS-TPP NPs purified by dialysis.