The aim of this study was to investigate the thermal properties of bambangan kernel fat (BKF) and palm stearin (PS) blends and their possibility as cocoa butter alternatives. The triglycerides, ...thermal behaviors, and crystal morphology of the BKF and PS blends were determined using high performance liquid chromatography (HPLC), differential scanning calorimetry (DSC), and polarized light microscope (PLM). All the blends had three main triglycerides; namely, 1,3-dipalmitoyl-2-oleoyl-glycerol, 1-palmitoyl-2-oleoyl-3-stearoyl-glycerol, and 1,3-distearoyl-2-oleoyl-glycerol. The melting onset temperatures decreased for both non-stabilized (−8.81 to −16.80 °C) and stabilized fat blends (−14.04 to −22.16 °C), whereas the melting offset temperatures shifted toward high temperatures for both non-stabilized (35.94–50.21 °C) and stabilized fat blends (48.35–53.16 °C) with PS. The crystallization onset temperatures increased for both non-stabilized (14.66–23.78 °C) and stabilized fat blends (15.46–26.89 °C), whereas the offset temperatures decreased with the addition of PS for non-stabilized (−15.68 to −22.02 °C) and stabilized fat blends (−15.73 to −22.38 °C). The stabilized fat blends showed higher melting and crystallization peak temperatures than non-stabilized fat blends. In the study of crystal morphology, the fat blends showed small spherulites with the diameter of 10–100 μm.
•Melting onset decreased for non-stabilized and stabilized fat blends with PS.•Melting offset shifted toward high temperatures for blends with PS.•Crystallization onset temperatures increased while offset decreased with PS.•Stabilized blends showed highest melting and crystallization than non-stabilized.•Blends showed small spherulites with the diameter of 10–100 μm.
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•CDs with green emission are successfully synthesized.•CDs have high pH sensitivity and selectivity with pKa of 6.0 ± 0.72.•Lysosome colocalization demonstrates that CDs can target ...lysosomes.•CDs can monitor pH changes in vitro and vivo.
The anomalous fluctuations of pH in lysosome will cause the disorder of normal activity of cells and even many diseases. Thus, developing a convenient strategy for tracking pH changes of lysosome is highly desired. Herein, carbon dots (CDs)-based fluorescent probe with lysosome-targeting function was fabricated. CDs can monitor pH changes in live cells and organisms, with the aid of confocal laser scanning microscope and noninvasive optical imaging system. The advantages of CDs including robust photostability, high pH sensitivity and selectivity, good reversibility and low toxicity render them a prominent candidate to investigate pH-associated physiological and pathological processes.
Given its central role in photosynthesis and artificial energy-harvesting devices, energy transfer has been widely studied using optical spectroscopy to monitor excitation dynamics and probe the ...molecular-level control of energy transfer between coupled molecules. However, the spatial resolution of conventional optical spectroscopy is limited to a few hundred nanometres and thus cannot reveal the nanoscale spatial features associated with such processes. In contrast, scanning tunnelling luminescence spectroscopy has revealed the energy dynamics associated with phenomena ranging from single-molecule electroluminescence, absorption of localized plasmons and quantum interference effects to energy delocalization and intervalley electron scattering with submolecular spatial resolution in real space. Here we apply this technique to individual molecular dimers that comprise a magnesium phthalocyanine and a free-base phthalocyanine (MgPc and H
Pc) and find that locally exciting MgPc with the tunnelling current of the scanning tunnelling microscope generates a luminescence signal from a nearby H
Pc molecule as a result of resonance energy transfer from the former to the latter. A reciprocating resonance energy transfer is observed when exciting the second singlet state (S
) of H
Pc, which results in energy transfer to the first singlet state (S
) of MgPc and final funnelling to the S
state of H
Pc. We also show that tautomerization of H
Pc changes the energy transfer characteristics within the dimer system, which essentially makes H
Pc a single-molecule energy transfer valve device that manifests itself by blinking resonance energy transfer behaviour.
•The Cu/PDA/GO nanocomposites were fabricated by a simple wet chemical reduction method.•The Cu/PDA/GO nanocomposites as lubricating additives can provide stable friction in a very short period of ...time.•The internal shear in the transfer films of Cu/PDA/GO nanocomposites can improve the tribological behaviors of the base oil.
A simple wet chemical reduction method was developed to prepare in situ growth of Cu nanoparticles (NPs) decorated on polydopamine (PDA) functionalized graphene oxide (GO) nanosheets. The immobilized Cu NPs with diameters of 10–15nm were uniformly distributed on PDA/GO nanosheets. The PDA layer on the surface of GO not only provides an activated platform for the uniform Cu NPs immobilization, but also remains abundant functional groups in Cu/PDA/GO nanocomposites even if after Cu NPs decorating on PDA/GO surface, which give rise to good dispersibility of Cu/PDA/GO nanocomposites in the base oil. In tests with sliding steel surfaces, the soybean oil with 0.1wt% Cu/PDA/GO nanocomposites exhibited the lowest friction coefficient under all of the sliding conditions. Optical microscope images of the wear scar of the steel disc showed that Cu/PDA/GO nanocomposites exhibited higher antiwear capability than Cu NPs, GO and Cu/GO. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy (Rm) of the worn surface lubricated by the soybean oil with Cu/PDA/GO nanocomposites showed that formation of low shear strength tribofilms containing Cu/PDA/GO nanocomposites and its self-lubricating property was key factor in reduction of the friction and protection against wear and deformation.
Intrinsic self-healing materials rely on a reversible bond formation after failure. In this study we report hybrid materials that contain two intrinsic self-healing forces: The reversible covalent ...bond formation of Diels–Alder groups is supported by intrinsic hydrogen bonds, which form supramolecular interactions and contribute to the mobility and proximity of the DA groups. This concept was realized by a combination of urea group containing spherosilicates with butyl methacrylate based polymers bearing both DA moieties and self-assembling hydrogen bonds. Multifunctional one-component polymers were synthesized and studied regarding their application in self-healing hybrid materials. The self-healing behavior was investigated following the signals for bond release and formation of DA groups in the material using IR, UV-vis, and CP-MAS NMR spectroscopy. Furthermore, DSC and rheological measurements were performed and revealed that the materials are superior compared to previously studied systems concerning their healing capacity. The self-healing behavior of the formed hybrid materials was proven by a cut healing test of several millimeters using microscope images. We can conclude that it is advantageous to combine several reversible functions in one material to promote the self-healing capacity particularly in nanocomposites where the flexibility of the network is restricted.
Nematic quantum fluids with wave functions that break the underlying crystalline symmetry can form in interacting electronic systems. We examined the quantum Hall states that arise in high magnetic ...fields from anisotropic hole pockets on the Bi(111) surface. Spectroscopy performed with a scanning tunneling microscope showed that a combination of single-particle effects and many-body Coulomb interactions lift the six-fold Landau level (LL) degeneracy to form three valley-polarized quantum Hall states. We imaged the resulting anisotropic LL wave functions and found that they have a different orientation for each broken-symmetry state. The wave functions correspond to those expected from pairs of hole valleys and provide a direct spatial signature of a nematic electronic phase.
Geopolymers are considered to be a sustainable and environmentally friendly replacement for ordinary Portland cement as they lead to a reduction in carbon footprint. The dosage and type of precursors ...and alkali activators have been known to be important parameters affecting the fresh and hardened properties of geopolymers. This study investigates the effect of slag content as well as type and dosage of alkali activators on one-part fly ash-based geopolymers cured at room temperature. Different ratios of fly ash were replaced with slag as a CaO-rich precursor. Setting time and flowability tests were carried out to evaluate the fresh properties, compressive and flexural strength experiments were conducted to determine the mechanical properties of the geopolymers. The mineralogy and microstructure of the samples were evaluated by Optical microscope, X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM-EDS) analysis. The experimental results revealed that the increase of slag content improved the strength and reduced workability. Moreover, some microcracks were observed when over 15% of fly ash was replaced with slag. In terms of activators, the sodium metasilicate anhydrous provided optimum strength and higher flowability compared to the others. Microstructural analysis results showed the presence of more unreacted particles when less than 8% Na2SiO3 content as alkaline activator and also less than 15% slag as replacement was used in the system.
•One-part FA-based geopolymers were optimized for curing at room temperature.•FA replacement beyond 15% caused microcracks and decreased the flexural strength.•8% is the minimum threshold of Na2SiO3 in the system.•The optimum workability and mechanical strength was achieved using Na2SiO3.
This study evaluates and compares the responses of two kinds of lignocellulosic biomass (pine and acacia) and sewage sludge to their hydrothermal carbonization treatment. All materials were subjected ...to HTC processes in an aqueous environment at 200 °C for 4 h with a 1:8 biomass to water ratio, using a Zipperclave Stirred Reactor. The physical, chemical analyses and, additionally, fibre, mercury porosimetry analyses and optical microscope images applied to both raw materials and to hydrochars, proved that HTC enhances the energy related properties of lignocellulosic biomass. Whereas, for sewage sludge, the HTC effect is negligible, because most of the carbon is transferred to the HTC liquid phase, confirmed by high COD and high ash content in the sewage sludge hydrochar. Subsequently, the thermo-chemical conversion kinetics of the raw and HTC materials were examined in the TGA analyser through nonisothermal runs. Finally, kinetics analyses were performed by two methods based on the TGA results. The estimated apparent activation energy values obtained by the Coats & Redfern method were higher than those given by the Arrhenius method, which also gave almost similar values for all samples, shedding doubt on the accuracy of this method for the current experiments. The Coats & Redfern analysis gave activation energy values which were lower by one half for sewage sludge hydrochars compared to lignocellulosic hydrochars. This indicates the potential of the HTC process for generating sewage sludge hydrochars suitable for co-combustion or co-gasification with other biomass solid fuels.
•Comparison of HTC treatment of acacia, pine and sewage sludge is presented.•Physico-chemical, fibre, and SEM proved that HTC enhances energy properties.•For sewage sludge, the HTC effect is negligible.•Activation energy for hydrochars was lower than for raw materials.
Weyl semimetals host topologically protected surface states, with arced Fermi surface contours that are predicted to propagate through the bulk when their momentum matches that of the surface ...projections of the bulk's Weyl nodes. We used spectroscopic mapping with a scanning tunneling microscope to visualize quasiparticle scattering and interference at the surface of the Weyl semimetal TaAs. Our measurements reveal 10 different scattering wave vectors, which can be understood and precisely reproduced with a theory that takes into account the shape, spin texture, and momentum-dependent propagation of the Fermi arc surface states into the bulk. Our findings provide evidence that Weyl nodes act as sinks for electron transport on the surface of these materials.
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•Cu-BTC MOF was directly in-grown within synthetic fabrics by using simple technique.•Contents of MOF and Cu were 97.14–127.33 mg/g and 30.5940.10 mg/g, respectively.•Cu-BTC/fabric ...was exhibited good biological activities against different microbes.•The MIC for the residual MOF powder was 60–70 mg/mL, for the different microbes.•At using 10 mg/mL, no eco-toxicity was detected for Cu-BTC/fabric hybrid.
Bio-active synthetic fabrics based on polyester (PET) and Nylon were manufactured by in-situ formation of Cu-BTC metal organic framework (MOF). In-growth of Cu-BTC within fabrics was accomplished in one pot simple process. The scanning microscope, X-ray diffraction and infrared spectra were all confirmed the formation of Cu-BTC within fabrics structure and reflected the role of fabrics' building unit in the Cu-BTC preparation. The estimated contents of materials onto fabrics were ranged in 97.14–127.33 mg MOF/g fabric and 30.59–40.10 mg Cu/g fabric. After embracing with Cu-BTC, color of fabrics was transformed to greenish-blue. The so-produced Cu-BTC/fabric hybrids were exhibited good biological activities against three different microbial pathogens (E. coli, S. aureus and C. albicans). The minimal inhibitory concentrations from the residual Cu-BTC powder were 65–70, 60–64 and 62–67 mg/mL, for S. aureus, E. coli and C. albicans pathogens, respectively, which were similar to that reported for commercial Cu-BTC. Moreover, no toxicity was observably detected for the released Cu-BTC from fabrics against brine shrimp at 10 mg/mL. These results revealed that, the in-growth of Cu-BTC resulted in production of biocidal synthetic fabrics without any ecotoxic effects at the as-used Cu-BTC content.
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