STA Analysis Research Articles

Rosemary particle as a new green additive to improve polysulfone membrane separation performance in removal of organic pollutants

This study used rosemary particles to make PSf nanofiltration membranes with antifouling properties, for medicinal pollutants and Azo dyes removal. The extract of rosemary plant was extracted using the Soxhlet process. Then homogeneous rosemary particles were embedded in the PSf membrane matrix as a green additive using the NIPS method. Characterization of the structure and morphology of rosemary particles and membranes was performed by FTIR, XRD, UV–Vis, FE-SEM, STA, DLS, ATR-FTIR, SEM, AFM, Zeta potential and TGA analyses. The results indicated the formation of homogeneous, hydrophilic, and spherical particles with a negative surface charge as well as physical stability in aqueous solutions and high thermal stability with a particle size of about 229 nm. Adding the optimal amount of rosemary particles increased the hydrophilicity (reduced water contact angle from 60.55° to 52.15°) and porosity (increased from 69.3 to 91.7%). Also, by adding 1 wt% of rosemary particles, the permeability of the membrane increased by 3.5 times. The increase in mean pore radius (from 4.77 to 6.08 nm), smoother surface of modified membranes and negative charge on the membrane surface proved this improvement. Therefore, the amount of 1 wt% caused the best flux performance of pure water (from 126 to 359 LMH) and BSA solution (from 104.5 to 202.3 LMH). Moreover, RE/PSf membranes showed a high rejection for azithromycin: 81.98%, cefixime: 58.07%, O II: 71.75, RY 160: 81.71 and RB 5: 93.69%.

Role of Nb5+-Nd3+ co-dopant in morphotropic boundary of electrospun PZT nanoneedles: Study on dielectric and piezoelectric sensitivity

This study focused on the effects of individual and simultaneous modification of electrospun PZT nanostructures with doping by Niobium (Nb5+) and Neodymium (Nd3+) cations. The SEM, EDS, XRD, XPS, STA, and TEM analyses were performed to identify the role of the donor-acceptor on the morphology, crystallography, and morphotropic boundary (MPB) of PZT nanostructures. The results indicated that the nanowhiskers of PZT were formed after post-calcination at 800 ℃ for 2 h. The morphology of the nanowhiskers was not changed drastically with individual doping by Nb and Nd while co-doping caused to morphology switch to the nanoneedles. The perovskite PZT phase; Pb(Zr0.58Ti0.42)O3 (Zr-rich, rhombohedral) phase was achieved with doping by Nb, while Pb(Zr0.52Ti0.48)O3 (Ti-rich, tetragonal) was determined with doping by Nd. With the de-convolution of the Zr 3d spectrum of XPS, it was exhibited that the nearest composition to MPB was attributed to Nb-Nd co-doped PZT. The polycrystalline fiber arranged by tetragonal-rhombohedral was observed. It was also found that the concentration of oxygen vacancy was reduced with doping by Nb, while increased with doping by Nd. The dielectric properties of un-doped and doped PZT were investigated. The dielectric constant of PZT was increased with individual doping by Nb and Nd, while due to the donor-acceptor couple, a synergistic effect was observed for co-doping by Nb-Nd where maximum dielectric was 16 times higher than the un-doped PZT. Also, with measuring the output voltage, the highest piezoelectric sensitivity was observed in the Nb-Nd co-doped PZT sample. Our findings highly suggest the electrospinning method for achieving the nanostructured PZT to be employed in a variety of applications needs a high dielectric constant.

Material extrusion additive manufacturing of advanced ceramics: Towards the production of large components

Thermoplastic extrusion based additive manufacturing (MEX-AM), is a very interesting fabrication method for the shaping of larger ceramic parts. Commercial filaments are currently available in the market, but due to the lack of information from the suppliers, it is not easy to select the suitable filament material for the 3D printing of individual ceramic objects. In this study, three commercial yttria-stabilized zirconia (YSZ) filaments provided by Fabru GmbH, SiCeram GmbH and PT+A GmbH were investigated. According to our results, it is possible to print YSZ filaments with extremely different flexibility and rheological properties. Compared to the other two filaments, the Fabru filament resulted in significantly higher flexibility, but the extrusion pressure to print it through a 0.25 mm nozzle was significantly higher at 150 °C. Interestingly, in the SiCeram filament, a grain orientation effect could be observed. Based on STA analysis it can be assumed that for the Fabru filament, the polymer which decomposes at a high temperature can already be removed by solvent debinding (SD). Finally, 70 mm tall cup structure including overhang features and different wall thicknesses was used to evaluate the printing and post-processing of YSZ filaments.

Hantzsch reaction using copper nitrate hydroxide-containing mesoporous silica nanoparticle with C3N4 framework as a novel powerful and reusable catalyst

Copper nitrate hydroxide (CNH)-containing mesoporous silica nanoparticle (MSN) with g-C3N4 framework (MSN/C3N4/CNH) was fabricated via a four-step hydrothermal synthesis method. Functionalized MSN-based C3N4 was prepared, decorated with CNH, and identified by different physicochemical techniques such as FT-IR, XRD, SEM, EDX, and STA analyses. Then, MSN/C3N4/CNH composite was utilized as a robust catalyst for the fast fabrication of biologically active polyhydroquinoline derivatives with high yields between 88 and 97% via Hantzsch reaction under mild reaction conditions and short reaction time (within 15 min) owing to synergistic influence of Lewis acid and base sites. Moreover, MSN/C3N4/CNH can be straightforwardly recovered and used up to six reaction cycles without a conspicuous decrease in efficiency.

Stability of 3Y-TZP nano zirconia powder after hydrothermal ageing treatment

ABSTRACT Yttria-stabilised zirconia (Y-TZP) ceramics are widely used for dental and prosthesis applications; however, they are susceptible to low-temperature degradation (LTD). Despite several explanations of the LTD mechanism, it is not fully understood yet. Commercial TZ-3Y-E grade powder was used to further study the LTD before sintering it. Hydrothermal ageing treatment was applied to samples at 134°C for 5 h. STA analysis confirmed that the powder is binderfree. SEM and XRD analyses show homogeneous particle size and tetragonal as a major phase and monoclinic as a minor phase, respectively. BET method analysis shows a slight change in the pore size, pore volume and surface area of the powder samples, before and after heating at 400°C. Particle size distribution (SD) calculated from SEM images shows ∼ 40–50 nm particle size range of the powders. The results show that LTD was not observed in the powder after hydrothermal ageing treatment.

Hybrid nanoarchitectonics of cellulose-PMAA/layered double hydroxide: A novel reusable catalyst for the unsymmetrical Hantzsch reaction

In this study, NiCo-layered double hydroxide (LDH) was fabricated in situ on the surface of CB-poly(methacrylic acid) (CB-PMAA) to form CB-PMAA/LDH nanocomposite. CB-PMAA was prepared via the radical polymerization of methacrylic acid (MAA) monomer onto the surface CB molecules. CB-PMAA/LDH was identified by FT-IR, XRD, SEM, EDS, and STA analyses and applied as a robust catalyst for the quick fabrication of biologically active polyhydroquinoline derivatives using unsymmetric Hantzsch reaction. CB-PMAA/LDH exhibits high reactivity for the construction of polyhydroquinolines with high yields (90-97%) under mild reaction conditions and short reaction time (10-20 min). Additionally, CB-PMAA/LDH can be straightforwardly recovered and used up to six reaction cycles without a conspicuous decrease in efficiency.

Effects of isothermal microwave curing on steel fibre-reinforced reactive powder concrete: Strength, microstructure and hydration products

A combined application of microwaving curing and reactive powder concrete (RPC) may provide an accelerated development of outstanding mechanical and physical properties, which has great potential to improve the quality and efficiency of production. In this work, a custom-made microwave oven was used to isothermally cure RPC with steel fibre reinforcement at 40 °C, 60 °C and 80 °C for 30 min. Compared to phased nonisothermal microwave curing, the isothermal microwave curing is equally effective, yet more energy efficient to operate and easier to control. The microwave-cured specimens at 1 day gained up 72.0% and 127.6% of the 28 days compressive and flexural strength achieved with standard curing, respectively. The acceleration rates varied with material characteristics and initial temperatures. The characterisation data obtained from STA, XRD and SEM-EDS analysis indicated that the beneficial effects of microwave curing temperature on strength development were due to the accelerated cement hydration and pozzolanic reaction of silica fume. The products resulting from this acceleration strengthened the interfacial zone between hydrated regions and aggregates, and the interfacial zone between the cement and silica fume. Besides C-S-H, AFm, AFt, CH, CC-, Al-tobermorite, a CO32−-contained fukalite-like phase was found to be formed, which may be produced by the pozzolanic reaction of silica fume at the expense of calcium carbonate under microwave curing.

Formation and hydration of eco-friendly cement using industrial wastes as raw materials

In this work, the optimal conditions of the synthesis of eco-friendly cement by using industrial wastes as well as the peculiarities of its early stage hydration were investigated. The eco-friendly cement was synthesized within the 1000–1250 °C temperature range when the targeted composition was 60% of belite, 20% of ye’elimite, and 20% of brownmillerite. It was determined that the optimal sintering temperature for eco-friendly cement is 1100 °C because the primary compounds were fully reacted, and hydraulic active compounds were dominant in the products. Microcalorimetry analysis was performed for the investigation of early stage hydration. The best results of hydration were obtained with the eco-friendly cement which was produced by using mixtures with silica gel waste: three exothermic reactions were observed in the heat evolution curve, while the cumulative heat was equal to 264 J/g after 72 h. Additionally, the sequence of compounds formation during the first day of hydration was analyzed. It was determined that the composition of the initial mixture impacts the hydration rate of synthetic eco-friendly cement; however, it did not affect the mineralogical composition of the hydration products. These results were confirmed by XRD, STA, and SEM analysis.

Physical and Mechanical Properties of Sustainable Hydraulic Mortar Based on Marble Slurry with Waste Glass

This paper aims to propose and characterize a sustainable hydraulic mortar entirely obtained by the reuse of waste materials, with marble slurry coming from quarries in the north-western Sicily and glass powder coming from a waste collection plant in Marsala (Province of Trapani). The first was used as raw material to produce the mortar binder by a kilning and slaking process, while the second was used as a pozzolanic additive. The chemical and morphological characterization of the marble slurry was done by XRD, FTIR, STA and SEM analyses. Glass powder was analyzed through particle size distribution measurements, XRD and standard pozzolanic tests. Hydraulic mortars constituted by slaked lime from kilned marble slurry and waste glass powder (LGS) were prepared beside commercial Natural Hydraulic Lime (NHL) based mortars (NGS) and air-hardening lime (LSS)-based mortars. Mechanical and absorption properties of the mortars were investigated as a function of the grain size of the glass powder by means of three-point bending and compressive strength tests, capillary uptake, helium pycnometry and simultaneous thermal analysis. The results demonstrated that the formulation LGS exhibits significantly improved mechanical and absorption properties compared to air-hardening mortars (LSS). It confirms the possibility of producing a more sustainable hydraulic mortar exclusively from waste materials for civil engineering.

Synthesis and characterisation of wollastonite with aluminium and fluoride ions

This work aims to investigate the influence of aluminium and fluoride ions on the mechanism of wollastonite formation during a two-step synthesis. For the synthesis, three mixtures with different chemical compositions were prepared. The first step of the synthesis was carried out under hydrothermal conditions (stirring – 50 rpm; 200 °C, 4–48 h); the second step was carried out in a furnace with a temperature range of 900–1100 °C for 1 h. The chemical composition of the primary mixture has been determined to exert a significant influence on the mineralogical composition of the hydrothermal synthesis products, since tobermorite and xonotlite dominated in the pure system, while tobermorite and cuspidine dominated in the mixture with aluminium and fluoride ions. After calcination of the precursors, pure wollastonite was obtained using a mixture of amorphous silica and calcium oxide, while in the other two mixtures, it was identified together with wollastonite cuspidine and fluormayenite or gehlenite. Dilatometric and BET analyses of the products showed that Al3+ and F− ions caused densification and loss of porosity during the formation of wollastonite. The synthesised products were characterised by STA, XRD, DIL and BET analyses.

Fabrication of efficient Zn-MOF/COF catalyst for the Knoevenagel condensation reaction

In this study, a hybrid material was successfully fabricated through the hybridization of zinc-based metal–organic framework (Zn-MOF) and covalent organic framework (COF) based on melamine and terephthaldehyde (Zn-MOF/COF) and characterized by FT-IR, SEM, XRD, and STA analysis. Then, the resultant hybrid was employed as an amazing and cost-effective catalyst in the condensation of a variety of aldehydes with malononitrile under solvent-free conditions at 25 °C in a short time (5–60 min) to offer benzylidenemalononitrile derivatives in high yields (82–100%). The catalyst could be reused without a noteworthy drop in catalytic activity at least eight times. The use of Zn-MOF/COF catalyst outcomes under mild reaction conditions in very short reaction time, exceptional catalytic activity, high recyclability and an easy work-up process for the Knoevenagel condensation.

Formation mechanism for synthesis of Ti3SnC2 MAX phase

The formation mechanism of Ti3SnC2 was evaluated in the present work. A stoichiometric ratio of a Ti-Sn-C powder mixture was prepared and milled for 50 h. To synthesize and detect intermediate reactions, a 50 h milled sample was thermally analyzed by STA. XRD instrument was utilized to detect phases of powder samples and the microstructure of the final product was obtained by SEM. The results showed that only Ti6Sn5 and Ti5Sn3 with Fe3Sn2 formed after 50 h milling, and no peaks related to MAX phases were found. To detect the reaction mechanism, the 50 h milled powder after STA analysis was characterized by XRD. Many intermediate reactions such as TixSny, TiC, and Ti2SnC formations took place. The melting of FexSny during STA analysis promoted the Ti3SnC2 formation. These results confirmed that Ti3SnC2 formation is not happened by a single reaction and many intermediate phases must be formed and Ti3SnC2 was synthesized after 50 h ball milling and thermally treated by STA analysis to 1400 °C.

Signal Transduction Pathway Activity in High-Grade, Serous Ovarian Carcinoma Reveals a More Favorable Prognosis in Tumors with Low PI3K and High NF-κB Pathway Activity: A Novel Approach to a Long-Standing Enigma.

Simple SummaryAll cells have a complex internal network of ‘communication chains’ called signal transduction pathways (STPs). Through interaction of different proteins in STPs, they are partly responsible for the behavior of a cell. In our study, we investigated the activity of eight STPs in datasets with genetic information on 140 cancer samples. These samples were derived from the most common subtype of ovarian cancer: high grade serous ovarian carcinoma (HGSC). With a novel method, we determined which STPs were active and discerned two groups based on activity of the phosphoinositide 3-kinase (PI3K) and nuclear factor-kappa B (NF-kB) pathways. The group with low PI3K and high NF-kB activity had a better progression free and overall survival compared to the group with high PI3K and low NF-kB activity. This difference may indicate that the ‘better prognosis group’ had a more active immune system or that the cells divided at a slower rate.We investigated signal transduction pathway (STP) activity in high-grade serous ovarian carcinoma (HGSC) in relation to progression-free survival (PFS) and overall survival (OS). We made use of signal transduction pathway activity analysis (STA analysis), a novel method to quantify functional STP activity. Activity of the following pathways was measured: androgen receptor (AR), estrogen receptor (ER), phosphoinositide 3-kinase (PI3K), Hedgehog (Hh), Notch, nuclear factor-kappa B (NF-κB), transforming growth factor beta (TGF-β), and Wnt. We selected HGSC samples from publicly available datasets of ovarian cancer tissue, and used repeated k-means clustering to identify pathway activity clusters. PFS and OS of the clusters were analyzed. We used a subset of publicly available dataset GSE9891 (n = 140), where repeated k-means clustering based on PI3K and NF-κB pathway activity in HGSC samples resulted in two stable clusters. The cluster with low PI3K and high NF-κB pathway activity (n = 72) had a more favorable prognosis for both PFS (p = 0.004) and OS (p = 0.001) compared to the high-PI3K and low-NF-κB pathway activity cluster (n = 68). The low PI3K and high NF-κB pathway activity of the favorable prognosis cluster may indicate a more active immune response, while the high PI3K and low NF-κB pathway activity of the unfavorable prognosis cluster may indicate high cell division.

Synthesis of Co-MOF/COF nanocomposite: application as a powerful and recoverable catalyst in the Knoevenagel reaction

A novel mesoporous composite was prepared through the hybridization of cobalt-based metal-organic framework (Co-MOF) and covalent organic framework (COF) based on melamine and terephthaldehyde (Co-MOF/COF) and characterized by FT-IR, SEM, XRD, EDS, BET, and STA analyses. The resultant composite was utilized as a robust recoverable catalyst in the condensation of several aldehydes with malononitrile to produce benzylidenemalononitrile derivatives in 62–94% yields under solvent-free conditions at room temperature using 15 mg of the catalyst and 5–60 min of reaction. The examination of catalytic performance of designated Co-MOF/COF exhibited an outstanding activity for the Knoevenagel condensation in a very short time. The recoverability, reusability and durability of Co-MOF/COF have also been investigated under applied conditions.

Influence of Cr3+, Co2+ and Cu2+ on the formation of calcium silicates hydrates under hydrothermal conditions at 200 °C

ABSTRACT This work aims to investigate the influence of Cr3+, Co2+ and Cu2+ on the formation of calcium silicates hydrates in CaO-SiO2-Al2O3-H2O system under hydrothermal conditions. The dry primary mixture with the molar ratio CaO/(SiO2+ Al2O3) = 1.5 and Al2O3/(Al2O3+ SiO2) = 0.05 was mixed with heavy metal nitrate solutions (metal ions concentration – 10 g/l) to reach the water/solid ratio of the suspension equal to 10.0. The hydrothermal synthesis was carried out in unstirred suspensions, under saturated steam pressure at 200°C temperature for 0–72 hours. It was determined that nature of metal ions have influence on both mineral composition and thermal stability of synthesis products. It was obtained that by increasing synthesis temperature up to 200°C, all Cr3+ and Co2+ ions were intercalated into the structure of synthesis products. Meanwhile Cu2+ ions participate in chemical reactions and as a result copper oxide were formed. The products of synthesis were characterized by STA, DSC, XRD and AAS analyses.

Nano-Graphene Oxide-supported APTES-Spermine, as Gene Delivery System, for Transfection of pEGFP-p53 into Breast Cancer Cell Lines.

PurposeGenetic diseases can be the result of genetic dysfunctions that happen due to some inhibitory and/or environmental risk factors, which are mostly called mutations. One of the most promising treatments for these diseases is correcting the faulty gene. Gene delivery systems are an important issue in improving the gene therapy efficiency. Therefore, the main purpose of this study was modifying graphene oxide nanoparticles by spermine in order to optimize the gene delivery system.MethodsGraphene oxide/APTES was modified by spermine (GOAS) and characterized by FT-IR, DLS, SEM and AFM techniques. Then pEGFP-p53 was loaded on GOAS, transfected into cells and evaluated by fluorescent microscopy and gene expression techniques.ResultsFT-IR data approved the GOAS sheet formation. Ninety percent of the particles were less than 56 nm based on DLS analysis. SEM analysis indicated that the sheets were dispersed with no aggregation. AFM results confirmed the dispersed structures with thickness of 1.25±0.87 nm. STA analysis showed that GOAS started to decompose from 400°C and was very unstable during the heating process. The first weight loss up to 200°C was due to the evaporation of absorbed water, the second one observed in the range of 200–550°C was assigned to the decomposition of labile oxygen- and nitrogen-containing functional groups, and the third one above 550°C was attributed to the removal of oxygen functionalities. In vitro release of DNA demonstrated the efficient activity of the new synthesized system. Ninety percent of the cells were transfected and showed the GFP under fluorescence microscopy, and TP53 gene was expressed 51-fold in BT-20 cells compared to β-actin as the reference gene. Flow cytometry analysis confirmed the apoptosis of the cells rather than necrosis.ConclusionIt could be concluded that the new synthesized structure could transfer a high amount of the therapeutic agent into cells with best activity.

Cellulose stabilized Fe3O4and carboxylate‐imidazole and Co‐based MOF growth as an exceptional catalyst for the Knoevenagel reaction

In this study, Fe3O4nanoparticles were functionalized with cellulose, and then hybridized with cobalt (II)‐based metal‐organic framework (Co‐MOF) containing carboxylate and imidazole functionalities. FTIR, XRD, FE‐SEM, TEM, BET, EDX, VSM and STA analyses were used to characterize the synthesized samples. The resultant Fe3O4/cellulose/Co‐MOF nanocomposite was applied efficiently as a powerful and economic heterogeneous catalyst in the condensation of a variety of different aromatic aldehydes with malononitrile under solvent‐free conditions at room temperature for 10 min and offered the corresponding coupling products in high yields. The catalyst could be straightforwardly separated by a magnet from the reaction mixture and reused without a noteworthy drop in catalytic activity at least five times. The use of Fe3O4/cellulose/Co‐MOF catalyst outcomes under mild reaction conditions in very short reaction time, outstanding catalytic activity, high recyclability and an easy work‐up process for Knoevenagel condensation.

Direct pathway neurons in mouse dorsolateral striatum in vivo receive stronger synaptic input than indirect pathway neurons.

Striatal projection neurons, the medium spiny neurons (MSNs), play a crucial role in various motor and cognitive functions. MSNs express either D1- or D2-type dopamine receptors and initiate the direct-pathway (dMSNs) or indirect pathways (iMSNs) of the basal ganglia, respectively. dMSNs have been shown to receive more inhibition than iMSNs from intrastriatal sources. Based on these findings, computational modeling of the striatal network has predicted that under healthy conditions dMSNs should receive more total input than iMSNs. To test this prediction, we analyzed in vivo whole cell recordings from dMSNs and iMSNs in healthy and dopamine-depleted (6OHDA) anaesthetized mice. By comparing their membrane potential fluctuations, we found that dMSNs exhibited considerably larger membrane potential fluctuations over a wide frequency range. Furthermore, by comparing the spike-triggered average membrane potentials, we found that dMSNs depolarized toward the spike threshold significantly faster than iMSNs did. Together, these findings (in particular the STA analysis) corroborate the theoretical prediction that direct-pathway MSNs receive stronger total input than indirect-pathway neurons. Finally, we found that dopamine-depleted mice exhibited no difference between the membrane potential fluctuations of dMSNs and iMSNs. These data provide new insights into the question of how the lack of dopamine may lead to behavioral deficits associated with Parkinson's disease.NEW & NOTEWORTHY The direct and indirect pathways of the basal ganglia originate from the D1- and D2-type dopamine receptor expressing medium spiny neurons (dMSNs and iMSNs). Theoretical results have predicted that dMSNs should receive stronger synaptic input than iMSNs. Using in vivo intracellular membrane potential data, we provide evidence that dMSNs indeed receive stronger input than iMSNs, as has been predicted by the computational model.

Cu-metal-organic framework supported on chitosan for efficient condensation of aromatic aldehydes and malononitrile

In this study, a novel copper-based metal-organic framework (Cu-MOF)-immobilized modified chitosan (CS-CA), CS-CA/Cu-MOF, has been constructed easily and applied as an extremely efficient and economic mesoporous catalyst for the Knoevenagel condensation between aromatic aldehydes with malononitrile under mild reaction conditions. The resultant catalyst is characterized via various techniques including FTIR, XRD, FE-SEM, EDX, TEM, BET and STA analyses. The CS-CA/Cu-MOF was reused eight times without a noteworthy decrease in the catalytic activity. The use of CS-CA/Cu-MOF results in outstanding catalytic activity, high recyclability, very short reaction time at 25 °C, and an easy work-up process for the Knoevenagel condensation.

The application of silica gel waste for the two-step synthesis of wollastonite in temperature range of 200–950 °C

In this work, the possibility of applying silica gel waste for the production of wollastonite via both single- and two-step methods was investigated. For the synthesis of wollastonite, two initial mixtures with CaO/SiO2 molar ratio of 0.75 and 1.0 were prepared. The synthesis was done by single-step and two-step methods: one-step synthesis was carried out in 800–950 °C temperature range in high-temperature furnace, while two-step method was based on hydrothermal treatment in autoclave (w/s-10, 200 °C, 4–72 h) and calcination of obtained products (800–950 °C, 1 h). It was determined that by using single-step synthesis, only the negligible amount of wollastonite was formed. The different results were obtained after calcination of hydrothermal synthesis products at 850 °C temperature, because wollastonite was the main compound. The obtained results were confirmed by data obtained from the XRD and STA analyses and thermodynamic calculations.