Preparation of chitosan-hyaluronic acid microcapsules and its dynamic release behavior analysis in a 3D-printed microchannel system: Exploration and verification.

This research focuses on the challenges of efficiently constructing drug carriers and evaluating their dynamic release in vitro simulation. By using pickering emulsion and layer-by-layer self-assembly methods. The microcapsules had tea tree oil as the core material, SiO2 nanoparticles as stabilizers, and chitosan and hyaluronic acid as shell materials. The microencapsulation mechanism, as well as the effects of core-shell mass ratio and stirring, were discussed. Specifically, a dynamic circulation simulation microchannel system was designed and manufactured based on 3D printing technology. In this simulation system, the release rate of microcapsules is accelerated and the trend changes, with its behavior aligning with the Boltzmann model. The study demonstrates the advantages of self-assembled inorganic-organic drug-loaded microcapsules in terms of controllable fabrication and ease of functional modification, and shows the potential of 3D printed cyclic microchannel systems in terms of operability and simulation fidelity in drug and physiological analysis.

Simulating CH4 emissions from MSW landfills in China from 2003 to 2042 using IPCC and LandGEM models.

Anaerobic landfills have long been the primary means of municipal solid waste (MSW) disposal in China. Landfills are the third largest emission source of methane (CH4), which is the second most abundant greenhouse gas in the atmosphere and has a high greenhouse effect. To date, there have been no reliable model predictions of long-term CH4 emissions from landfills in China. In this study, two general models, IPCC and LandGEM, were introduced to simulate CH4 emissions from all landfills in China. By comparing the results of the Shuangkou landfill in Tianjin with the default and local parameters, the local parameters were fixed to simulate landfill CH4 emissions in 31 regions over 40 years (2003-2042). The MSW landfills were obtained from statistical data for 18 years (2003-2020). The total emissions in China predicted by LandGEM and IPCC were 2.42 E+07 Mg and 2.36 E+07 Mg, respectively. These data provide a reliable reference for determining the long-term CH4 emissions from landfills in China.

Effects of silica fume powder modified by oleic acid on the settleability of bulking sludge.

Modified silica fume powder with oleic acid through coupling agent was prepared based on the in situ utilizing long-chain fatty acids (LCFA) properties of Microthrix parvicella (M. parvicella) in the activated sludge system. The modification was confirmed by XRD and infrared spectrum. The contact angle analysis showed that the modification gave the silica fume powder a hydrophobic surface. The modified silica fume powder had a good combination with M. parvicella from the SEM and Gram staining measurements. The addition of modified silica powder has a certain effect on the settling capacity of sludge, but has little effect on the sludge treatment capacity, while the SVI dropped from 400.1 to 100.0 mL/g. These suggested that the modified silica fume powder could be used as an excellent weight-increasing agent to inhibit sludge bulking.

Chiral FA Conjugated CdTe/CdS Quantum Dots for Selective Cancer Ablation.

Inducing apoptosis in cancer cells is considered a potential therapeutic mechanism underlying cancers. Here, chiral folic acid (FA) conjugated Cys-CdTe/CdS quantum dots (QDs) conjugated with a cancer-targeting ligand were fabricated to induce apoptosis in vivo. Ligand-induced chirality mechanism for FA-Cys-CdTe/CdS QDs was discussed, which is verified by density functional theory (DFT) simulation. Interestingly, we found that the circular dichroism (CD) signals of chiral QDs can effectively distinguish breast cancer cells from normal cells, where a sharp decrease in CD signal and absorption intensity can be seen. Notably, chiral FA-Cys-CdTe/CdS QDs showed significant apoptosis-inducing ability after the release of mitochondrial apoptotic factors. Furthermore, in vivo experiments showed that chiral FA-Cys-CdTe/CdS QDs provide an efficient cancer ablation through the apoptosis process with negligible toxicity, demonstrating their great potential utility in targeted anticancer agent for future clinic application.

Interaction mechanism of novel fluorescent antifolates targeted with folate receptors α and ß via molecular docking and molecular dynamic simulations.

Eight novel fluorescent antifolates were designed and docked with folate receptors FRα and FRß. The structures of the complexes were further calculated by molecular dynamic (MD) simulations. The binding energies were calculated by molecular docking and molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) studies. The binding energy differences between FRα and FRß (|Ebα|-|Ebß|) values for compounds 3 and 8 were 1.3 and 1.1 kcal/mol calculated by molecular docking, and 13.9 and 10.4 kcal/mol by MM-PBSA simulation, respectively. The results indicated that compounds 3 and 8 may be the best candidates for targeted drug delivery to FRα. The binding structures, interaction residues, negatively charged pocket volume, and surface area were analyzed for all the complexes. We further calculated the root mean square displacement and secondary structural elements of the bound complexes using molecular dynamics simulations. The purpose of this study is to design novel antifolates targeted to FRα and FRß, and to further distinguish between cancer cells and inflammation.

Comparison between thermophilic and mesophilic anaerobic digestion of waste activated sludge by combined NaOH-microwave pretreatment.

The purpose of this study was to investigate the performance of the thermophilic and mesophilic anaerobic digestion process (TADP, MADP) fed with NaOH-microwave pretreated waste activated sludge. The experiment was conducted in anaerobic CSTR reactors. During this experiment, the reactors were stable in operation and were not inhibited by ammonia. The methane production and reduction of organic matters from MADP were less than those from TADP. The dewatering performance of mesophilic sludge was better than that of the thermophilic sludge. The experimental results showed that the continuous TADP and MADP were effective, when the reactors were fed with the waste activated sludge pretreated by NaOH-microwave. MADP was more suitable to combine the NaOH-MW pretreatment process than TADP.

Impact of light on anoxic/oxic reactors: performance, quorum sensing, and metagenomic characteristics.

The effect of light has raised attention on wastewater treatment. However, little research has concentrated on the influences of light on activated sludge. In this study, the influences of light on the performance, quorum sensing (QS) and metagenomic characteristics of anoxic/oxic reactors were investigated. The reactor without light (AO1) showed higher total nitrogen (TN) removal (79.15 ± 1.69%) than the reactor with light (AO2) (74.54 ± 1.30%), and significant differences were observed. It was observed that light facilitated the production of protein-like and tryptophan-like substances by employing parallel factor analysis for extracellular polymeric substance (EPS), resulting in more EPS production in AO2, indicating light was beneficial to EPS production. The concentrations of N-acyl-homoserine lactones (AHLs) were various in the two reactors, so the AHLs-mediated QS behaviors in both reactors were also different. These results revealed that light significantly influenced nitrogen removal, EPS, and QS. Metagenomic analysis based on Tax4Fun demonstrated that light reduced the denitrification, stimulated the polysaccharide and protein biosynthesis pathways and down-regulated the AHLs synthesis pathway, resulting in lower TN removal, more EPS production, and lower AHLs concentrations. Based on the above, the likely mechanism was proposed for the influences of light on the reactor.

Identification and elimination of cancer cells by folate-conjugated CdTe/CdS Quantum Dots Chiral Nano-Sensors.

The specific identification and elimination of cancer cells has been a great challenge in the past few decades. In this study, the circular dichroism (CD) of cells was measured by a self-designed special system through the folate-conjugated chiral nano-sensor. A novel method was established to recognize cancer cells from normal cells according to the chirality of cells based on their CD signals. After a period of interaction between the nano-sensor and cells, the sharp weakening of CD signals was induced in cancer cells but normal cells remained unchanged. The biocompatibility of the nano-sensor was evaluated and the result showed that it exhibited significant cytotoxic activity against cancer cells while no obvious damage on normal cells. Notably, the research indicated that the nano-sensor may selectively cause apoptosis in cancer cells, and thus, have the potential to act as an antitumor agent.

Simulation and experimental study of fluorescence labeled polyphosphate in microthrix parvicella.

To study the binding mechanism of 4',6-diamidino-2-phenylindole (DAPI) and polyphosphate (Poly-P) and find fluorescent dyes which can dye Poly-P better, the interaction model of DAPI and Poly-P was calculated by the self-consistent-charge, density functional tight-binding (SCC-DFTB-D) method, and the binding sites of DAPI and Poly-P were analyzed. Further, Cy3, Rhodamine 6G and Fluorescein, which are structurally similar to DAPI, were selected to analyze their interactions with Poly-P. The binding energies and frontier orbital properties of the complexes were analyzed. These four fluorescent dyes were further used to dye the activated sludge smear and observe the fluorescence property. The Simulation results show that the N-containing indole ring structures in DAPI plays an important role in the interaction with Poly-P; the binding energies for DAPI, Cy3, Rhodamine 6G and Fluorescein with Poly-P are -42.6, -165.4, -34.7 and -28.9 kcal/mol, respectively. The frontier orbital properties for the complexes were studied, which further indicates that the interactions between Cy3, Rhodamine 6G and Poly-P are stronger than that of Fluorescein and Poly-P. The experimental results showed that Cy3 had excellent dyeing effect on Poly-P and could recognize them, while Fluorescein could not dye Poly-P. The experimental results were in good agreement with those predicted by simulation, which verified the correctness of our calculation method and provided a new strategy for finding more reliable, more sensitive and more economical fluorescent dyes capable of dyeing Poly-P.

Type and size effect of functional groups on the novel antifolate target recognition folate receptors α and ß: Docking, molecular dynamics and MM/PBSA study.

A series of novel antifolates (32 compounds) were used to study the interactions with folate receptors α and ß. The compounds had different sizes of methyl (-CH3), carboxyl (-COOH), hydroxyl (-OH), and amino groups (-NH2). The binding properties of the complexes were studied by molecular docking, molecular dynamic (MD) simulations, and MM/PBSA free energy calculations. The docked binding energies and modes were analyzed to identify compounds with good recognition of FRα from FRß. The stable conformers, root mean square displacement, root mean square fluctuation free binding energy, and contribution of residues to the binding energy of the complexes were further analyzed to illustrate the interactions between the novel compounds and folate receptors. The data show that introducing long functional groups in folate will increase the binding affinity with FRα but will decrease the binding affinity with FRß. The results provide a strategy for the design of novel antifolates targeted to FRα.

Fluorescence and Optical Activity of Chiral CdTe Quantum Dots in Their Interaction with Amino Acids.

Ligand-induced chirality in semiconducting nanocrystals has been the subject of extensive study in the past few years and shows potential applications in optics and biology. Yet, the origin of the chiroptical effect in semiconductor nanoparticles is still not fully understood. Here, we examine the effect of the interaction with amino acids on both the fluorescence and the optical activity of chiral semiconductor quantum dots (QDs). A significant fluorescence enhancement is observed for l/d-Cys-CdTe QDs upon interaction with all the tested amino acids, indicating suppression of nonradiative pathways as well as the passivation of surface trap sites brought via the interaction of the amino group with the CdTe QDs' surface. Heterochiral amino acids are shown to weaken the circular dichroism (CD) signal, which may be attributed to a different binding configuration of cysteine molecules on the QDs' surface. Furthermore, a red shift of both CD and fluorescence signals in l/d-Cys-CdTe QDs is only observed upon adding cysteine, while other tested amino acids do not exhibit such an effect. We speculate that the thiol group induces orbital hybridization of the highest occupied molecular orbital (HOMOs) of cysteine and the valence band of CdTe QDs, leading to the decrease of the energy band gap and a concomitant red shift of CD and fluorescence spectra. This is further verified by density functional theory calculations. Both the experimental and theoretical findings indicate that the addition of ligands that do not "directly" interact with the valence band (VB) of the QD (noncysteine moieties) changes the QD photophysical properties, as it probably modifies the way cysteine is bound to the surface. Hence, we conclude that it is not only the chemistry of the amino acid ligand that affects both CD and PL but also the exact geometry of binding that modifies these properties. Understanding the relationship between the QD's surface and chiral amino acid thus provides an additional perspective on the fundamental origin of induced chiroptical effects in semiconductor nanoparticles, potentially enabling us to optimize the design of chiral semiconductor QDs for chiroptic applications.

Impact of the acetate/oleic acid ratio on the performance, quorum sensing, and microbial community of sequencing batch reactor system.

This study comprehensively investigated the impact of acetate/oleic acid ratios (80%/20%, 60%/40%, 40%/60%, and 20%/80%) on sequencing batch reactor (SBR) with respect to the variations in performance, quorum sensing (QS), and microbial community. Results showed that NH+4-N removal was not affected by the acetate/oleic acid ratios, while the COD, total nitrogen (TN), and PO3-4-P removal was considerably affected. The increasing oleic acid ratios led to severe sludge bulking, which was significantly positively correlated with proteins/polysaccharides (p < 0.001). The correlation of QS with the performance and sludge properties was also observed. High-throughput sequencing demonstrated that microbial compositions considerably shifted with varying acetate/oleic acid ratios. Moreover, the potential correlation of bacterial genera with the SBR performance and QS was proposed. This study elucidated the effect of acetate/oleic acid ratios on SBR from microbial viewpoint, which provided insights into fully understanding the essential roles of carbon source on wastewater treatment.

A novel dicationic Quinoline-Carzole fluorescent probe: preparation and labelling of Microthrix parvicella.

A novel dicationic Quinoline-Carbazole fluorescent probe with hydrophobic long-chain alkane was designed and synthesized based on the property of Microthrix parvicella (M. parvicella) in situ utilizing long-chain fatty acids (LCFA) in the activated sludge system. 1H NMR spectrum, ultraviolet-visible (UV-Vis) absorption spectra, and fluorescent spectra analysis demonstrated that the probe was successfully obtained. The probe had a large stokes-shift ranging from 102 to 144 nm in different solvents, which were benefit for the fluorescent labelling properties. The labelling experiment indicated that the prepared probe could absorb onto the surface of M. parvicella through hydrophobic bond. Much stronger yellow fluorescence of M. parvicella was observed at the concentration of 1.0 × 10-5 mol/L when compared with the zooglea, which makes it easy to distinguish M. parvicella from the zooglea. In addition, the photostability of the probe was also investigated, and the result showed that the probe was quite stable in a long period of time. All the results indicated that the prepared probe was suitable for the labelling of M. parvicella.

Insights into the effects of carbon source on sequencing batch reactors: Performance, quorum sensing and microbial community.

Effects of carbon source on the performance, quorum sensing (QS) and microbial communities in the sequencing batch reactors were investigated in this work. Among the chosen carbon source, sodium acetate (R1), glucose (R2), starch (R3) and Tween 80 (R4), sodium acetate was the best carbon source for nutrient removal, while starch was favorable for inducing the sludge bulking, and Tween 80 was beneficial to the production of extracellular polymeric substances (EPS) and proliferation of Microthrix parvicella. Additionally, the R2 value of linear correlation between sludge settleability and particle size in four reactors followed an order of R1 > R2 > R3 > R4. Moreover, Person correlation analysis showed that various significant correlations were observed in reactors fed with different carbon sources and the QS mainly mediated the production and component of EPS. High-throughput sequencing analysis revealed that the carbon source affected microbial communities and the Canonical correspondence analysis results indicated that QS related to microbial communities. It was inferred that the interactions between microbial communities and QS affected system performance.

Labeling of Microthrix parvicella in situ: A novel FRET probe based on bisoctyl rhodamine B.

Filamentous bacteria, particularly Microthrix parvicella, are mainly responsible for bulking or foaming of activated sludge. Based on the affinity of M. parvicella to the hydrophobic characteristics of long-chain fatty acids, a novel bisoctyl rhodamine B (BORB) and a novel fluorescence resonance energy transfer (FRET) complex probe were prepared herein to study their properties. When the FRET probe was used in in situ activated sludge, M. parvicella was clearly labeled at 20 nmol/L, which was a reduction of 50 times compared to that of the BORB (1 µmol/L) alone and 500 times compared to the carbazole-quinoline probe reported previously. Compared with fluorescence in situ hybridization, M. parvicella could be clearly labeled using BORB and the FRET probe in situ without requiring complicated pretreatments (i.e., shock and broken process, fixed sample, digestion, and lysozyme treatment). This study discusses the facile approach developed for labeling M. parvicella in early warning expansion, thereby inhibiting and controlling sludge bulking in situ.

The Fabrication of Fragrance Microcapsules and Their Sustained and Broken Release Behavior.

Their controlled release property is the most important feature of functional microcapsules and carriers. In this work, melamine resin shell fragrance microcapsules were fabricated in a non-ionic system, and their chemical structure, particle size, and morphology were analyzed. The sustained release property of the prepared microcapsules over 2400 h was studied with a weighing calculation method, and based on the fitting results, the release rate trend was consistent with the Peppas model (y = 100 - 2.30t0.3213). Furthermore, the sustained and broken release behavior of the microcapsules in impregnated fabric samples were investigated for the first time by our proposed Solid Phase Microextraction-Gas Chromatography-Mass Spectrometer (SPME-GC-MS) method. The qualitative and quantitative analysis results showed that the middle and base note compositions were outstanding in the sustained release state, and the top note showed more advantages in the broken release state. In addition, it was found that the characteristic peak species and intensities of the sample finished with the microcapsules were more similar to pure essence oil than the sample finished by traditional methods, suggesting that the prepared microcapsules showed an excellent odor recovery and strength.

Relation between the particle size and release characteristics of aromatic melamine microcapsules in functional textile applications.

The relation between the particle size and release characteristics of aromatic microcapsules with a melamine resin shell in functional textile applications have been investigated. Firstly, the microcapsules are characterized based on their Fourier transform infrared spectra, encapsulation efficiencies, particle size distributions, optical images, and scanning electron microscopy images. The impregnation performances of the microcapsules have been initially evaluated using image analysis. Subsequently, the impregnation efficiency and broken release characteristics are semi-quantitatively analyzed using solid-phase microextraction-gas chromatography-mass spectrometry. The analysis results show that the highest impregnation efficiency and broken release intensity could be observed when the microcapsule size was similar to the fiber diameter (25-30 µm). Eventually, the sustained release of the microcapsules over a period of 2400 h was evaluated using the weighing calculation method, and the trends were studied using the Peppas model. It was found that the microcapsule release rate slowly and continuously decreased with time, and the release rates significantly increased with the decrease in microcapsule particle size. Thus, it could be concluded that the large microcapsules exhibited better leak tightness than the small microcapsules, whereas the small microcapsules exhibited faster sustained release rates.

Interacted mechanism of functional groups in ligand targeted with folate receptor via docking, molecular dynamic and MM/PBSA.

Twenty novel compounds with different functional groups (-COOH, -OH, -NH2 and -CH3) were designed to study the interaction mechanism of ligands with folate receptors (FRs). The optimized structure and the dipole moment of the novel compounds were calculated by a density functional tight-binding method (DFTB). The binding mechanism of the compounds with FRs was studied by molecular docking, molecular dynamic (MD) simulations and MM/PBSA free energy calculations. The binding energies, root mean square displacement and root mean square fluctuation of the complexes were analyzed to further illustrate the effect of the functional groups. The functional groups play important roles in stabilizing the bound complexes. Compared to other groups, -OH is more stably linked with the compound. These data provide a theoretical basis for the design of novel compounds targeted with FRs.

Novel fluorescent antifolates that target folate receptors α and ß: Molecular dynamics and density functional theory study.

Nine novel fluorescent antifolates, 1-9, were designed and docked with FRα and FRß. The binding energies of the bound complexes were determined by molecular docking and MM-PBSA studies. The structural properties of the complexes FR-FOL, FR-7, FR-8 and FR-9 were analyzed in detail via molecular docking and molecular dynamics studies. We further calculated the root mean square displacement and root mean square fluctuation of the bound complexes using molecular dynamics simulations. Since compounds 7, 8 and 9 are promising candidate in distinguishing FRα from FRß, the hydrogen bond properties of complexes FRα-7, FRα-8 and FRα-9 were studied by a dispersion complemented density functional tight-binding method. The purpose of this study is to provide a rationale for the design of novel fluorescent antifolates targeted with FRα and FRß.

A novel fluorescent long-chain fatty acid-substituted dye: labeling and biodegrading of Microthrix parvicella.

Microthrix parvicella (M. parvicella) is a filamentous bacterium that induces bulking in activated sludge. Here, we used the affinity of long-chain fatty acids (LCFA) for M. parvicella to create a novel fluorescent probe of carbazole modified by LCFA. The structure was characterized by 1H NMR spectroscopy and mass spectrometry. The spectral properties, photostability, and hydrophobic properties of the probe were also characterized. Fluorescent-labeling results showed that it can label M. parvicella in situ and could be biodegraded via metabolism. The stable docking mode of carbazole probes with different fatty acid chains and lipases was also docked by the density functional tight-binding (DFTB) method.