Dimethyl Ammonium Chloride Research Articles

Elimination of inhibitory effects of dodecyl dimethyl benzyl ammonium chloride on microalgae in wastewater by cocultivation with a newly screened microbial consortium

As one of the most commonly used biocidal cationic surfactants, benzalkonium chlorides (BACs) have been an increasing concern as emerging contaminants. Wastewater has been claimed the main point for BACs to enter into the environment, but to date, it is still largely unknown how the BACs affect the microbes (especially microalgae) in the practical wastewater and how to cost-effectively remove them. In this study, the inhibitory effects of a typical BACs, dodecyl dimethyl benzyl ammonium chloride (DDBAC), on a green microalga Chlorella sp. in oxidation pond wastewater were investigated. The results showed that though a hermetic effect at the first 2 days was observed with the DDBAC at low concentration (<6 mg/L), the algal growth and photosynthesis were significantly inhibited by the DDBAC at all the tested concentrations (3 to 48 mg/L). Fortunately, a new microbial consortium (MC) capable of degrading DDBAC was screened through a gradient domestication method. The MC mainly composed of Wickerhamomyces sp., Purpureocillium sp., and Achromobacter sp., and its maximum removal efficiency and removal rate of DDBAC (48 mg/L) respectively reached 98.1 % and 46.32 mg/L/d. Interestingly, a microbial-microalgal system (MMS) was constructed using the MC and Chlorella sp., and a synergetic effect between the two kinds of microorganisms was proposed: microalga provided oxygen and extracellular polysaccharides as co-metabolic substrates to help the MC to degrade DDBAC, while the MC helped to eliminate the DDBAC-induced inhibition on the alga. Further, by observing the seven kinds of degradation products (mainly including CH5O3P, C6H5CH2-, and C8H11N), two possible chemical pathways of the DDBAC degradation were proposed. In addition, the metagenomic sequencing results showed that the main functional genes of the MMS included antibiotic-resistant genes, ABC transporter genes, quorum sensing genes, two-component regulatory system genes, etc. This study provided some theoretical and application findings for the cost-effective pollution prevention of BACs in wastewater.

A micro-crosslinked amphoteric hydrophobic association copolymer as high temperature- and salt-resistance fluid loss reducer for water-based drilling fluids

During ultradeep oil and gas drilling, fluid loss reducers are highly important for water-based drilling fluids, while preparing high temperature- and salt-resistance fluid loss reducers with excellent rheology and filtration performance remains a challenge. Herein, a micro-crosslinked amphoteric hydrophobic association copolymer (i.e., DADC) was synthesized using N,N-dimethyl acrylamide, diallyl dimethyl ammonium chloride, 2-acrylamido-2-methylpropane sulfonic acid, hydrophobic monomer, and pentaerythritol triallyl ether crosslinker. Due to the synergistic effects of hydrogen bonds, electrostatic interaction, hydrophobic association, and micro-crosslinking, the DADC copolymer exhibited outstanding temperature- and salt-resistance. The rheological experiments have shown that the DADC copolymer had excellent shear dilution performance and a certain degree of salt-responsive viscosity-increasing performance. The DADC copolymer could effectively adsorb on the surface of bentonite particles through electrostatic interaction and hydrogen bonds, which bring more negative charge to the bentonite, thus improving the hydration and dispersion of bentonite particles as well as the colloidal stability of the drilling fluids. Moreover, the drilling fluids constructed based on the DADC copolymer exhibited satisfactory rheological and filtration properties (FLHTHP = 12 mL) after aging at high temperatures (up to 200 °C) and high salinity (saturated salt) environments. Therefore, this work provided new insights into designing and fabricating high-performance drilling fluid treatment agents, demonstrating good potential applications in deep and ultradeep drilling engineering.

In Vitro and In Silico Analysis of the Antifungal Activity of Beta-cyclodextrin and Cinnamon Oil Inclusion Complexes against Fusarium oxysporum f. sp. cubense-TR4

The Panama Disease-TR4 is a fatal disease of banana plants caused by the fungus Fusarium oxysporum f. sp. cubense-TR4 (Foc-TR4). Cinnamon oil has known antifungal properties, while beta-cyclodextrin has been proven to protect essential oils from degradation through encapsulation. The study aims to determine the effectiveness of cinnamon oil, and its beta-cyclodextrin complex against Foc-TR4, through their characterization, in vitro antifungal screening, and in silico docking analysis. The characterization of the complex yielded an encapsulation efficiency of 61.18%, an average particle size of 98.27 μm, while its calorimetry confirmed complex formation. Cinnamon oil, beta-cyclodextrin, and the complex were tested against Foc-TR4 through spread plate method against Ivagard (dialkyl dimethyl ammonium chloride) in triplicate. Among the treatments, the complex exhibited significantly weaker antifungal activity, with only cinnamon oil comparable with Ivagard at α = 0.05. Cinnamaldehyde displayed favorable binding energies of -6.1 and -4.9 kcal/mol against the Foc-TR4 proteins, and -3.7 kcal/mol against beta-cyclodextrin. This implies that cinnamaldehyde can spontaneously form stable complexes with the Foc-TR4 proteins or beta-cyclodextrin. These findings suggest the potential of cinnamaldehyde, in cinnamon oil and even in the inclusion complexes, as a viable antifungal treatment against Foc-TR4.

Robust and Wet Adhesive Self-Gelling Powders for Rapid Hemostasis and Efficient Wound Healing.

Healing traumatic wounds is arduous, leaving miscellaneous demands for ideal wound dressings, such as rapid hemostasis, superior wet tissue adhesion, strong mechanical properties, and excellent antibacterial activity. Herein, we report a self-gelling, wet adhesive, stretchable (polyethylenimine/poly(dimethylammonium chloride)/(poly(acrylic acid)/poly(sodium styrenesulfonate)/alkylated chitosan)) ((PEI/PDDA)/(PAA/PSS)/ACS) powder as a new option. The self-gel utilizes noncovalent interactions among in situ formed PDDA/PSS nanoparticles and PEI/PAA polymetric matrices to earn sensational mechanical properties and tensile strength while incorporating ACS to obtain fast hemostasis and therapeutic capacities. The powder can form a hydrogel patch in situ within 3 s upon liquid absorption, capable of resisting pressure higher than twice the blood pressure. Deposition of the self-gelling powders on various wounds, such as rat liver and femoral artery wounds, can stop bleeding in 10 s and lessen the amount of bleeding 6-fold plus in corresponding models. Furthermore, the self-gelling powders can significantly advance the chronic wound healing process by displaying a high wound healing rate and a low inflammatory response and promoting the formation of new blood vessels and tissue regeneration. The satisfactory mechanical properties, strong wet adhesion, sufficient antibacterial properties, ease of usage, adaptability to complex wounds, rapid hemostasis, and superior therapeutic capacities of (PEI/PDDA)/(PAA/PSS)/ACS self-gelling powders render them as a profound wound dressing biomaterial.

Two‐Pronged Maneuver of Inner Regulation and Surface Repair for Stable Inorganic Perovskite Solar Cells with Ultralow Open‐Circuit Voltage Deficit

Despite inorganic perovskites are suitable for application into tandem solar cells, the unsatisfactory crystal quality and inevitable surface defects of low‐temperature fabricated inorganic perovskites lead to undesirable open‐circuit voltage (VOC) deficit, which limits the further development of inorganic perovskite solar cells (IPSCs). Herein, dimethylammonium chloride (DMACl) was introduced into perovskite precursor to prolong the solid‐state reactions between intermediate phases of DMAPbX3 and Cs4PbX6, and mediate crystallization process of inorganic perovskite, leading to obtain high‐quality CsPbI2.75Br0.25 perovskite films without DMA+ residue in perovskite films after annealing. Additionally, the energy level position of perovskite slightly downshift after adding DMACl, narrowing the band offsets between perovskite and carrier transport layers. To further reduce VOC deficit and improve the performance of IPSCs, cesium iodide (CsI) thin layer is evaporated onto the perovskite surface to repair inevitable I‐related defects. Ultimately, the VOC and performance of IPSCs are improved without introducing organic components into final perovskite films. A champion photoelectric conversion efficiency of 20.75% is achieved, and the VOC deficit is significantly decreased to 0.382 V, which is the minimum VOC deficit of IPSCs at present. Additionally, the stability of the perovskite films and IPSCs has also been remarkably enhanced.

Sulfonated cellulose nanocrystal modified with ammonium salt as reinforcement in poly(lactic acid) composite films

Poly(lactic acid) (PLA) composites reinforced with cellulose nanocrystals (CNCs) are promising biodegradable materials. However, the poor compatibility and dispersion of CNCs in the PLA matrix remain a significant obstacle to improving the properties of composites. In this study, the modified CNC (CNC-D) was prepared through sulfonation treatment, followed by modification with didecyl dimethyl ammonium chloride (DDAC). Then, CNC-D was mixed with PLA to prepare composite films (PLA-CNC-D). The results revealed that the PLA-CNC-D had higher tensile strength and elongation at break than PLA-CNC at 3 wt% nanofiller content, increasing by 41.53 and 22.18 %, respectively. SEM and DSC analysis indicated that surface modification improved the compatibility and dispersion of CNC-D in the PLA matrix. The sulfonation process increased the anion content on the surface of CNC-D, enabling the CNC-D surface to adsorb more cationic DDAC, consequently sharply reducing the hydrophilicity of CNC-D. Moreover, the PLA-CNC-D exhibited excellent antibacterial activity against S. aureus and E. coli. In summary, this study provides a novel CNC modification approach to enhance the physical properties and antibacterial activity of PLA composite films, enlarging the application of degradable PLA composites.

Preparation, characterization and application of a composite bioflocculant.

Composite flocculant PAFS-PDM was prepared from Polymeric aluminium ferric sulphate (PAFS) and Poly (diallyl dimethyl ammonium chloride) (PDM) in this study. A bacterium was selected from the soil near the shale gas exploitation platform as a bioflocculant-producing bacterium, and polysaccharide was extracted and combined with PAFS-PDM to obtain composite bioflocculant (CBF) to treat shale gas fracturing flowback fluid. The prepared CBF was characterized and the results showed that the prepared PAFS-PDM contained aluminium-iron hydroxyl polymer, which was a cationic flocculant. By measuring the turbidity removal rate and chemical oxygen demand (COD) removal efficiency, the function mechanism of CBF on the shale gas fracturing flowback fluid was discussed. The results showed that CBF had a stable treatment effect on fracturing flowback fluid when the pH value was about 7.0. With the increase of dosage, the coagulation efficiency increased first and then decreased. When the dosage of the CBF was 2500 mg·L-1, the treatment effect of shale gas fracturing flowback fluid was the best, and COD removal rate reached 89.43%. Through Zeta potential analysis, it was concluded that one of the coagulation mechanisms was electrical neutralization. According to the characterization results, it could be concluded that both adsorption bridging and charge neutralization mechanisms played important roles in the treatment of shale gas fracturing flowback fluids.

Development of a dual-functional inhibitor for natural gas hydrates and construction of drilling fluid system

Throughout the 21st century, natural gas hydrates have emerged as a pivotal and promising clean energy resource with immense potential for commercial development. However, during shallow-water gas hydrate drilling in deep-sea areas, heat and mass transfer between the drilling fluid and the natural gas hydrate reservoir result in hydrate dissociation. As a result, the reservoir strength is weakened, wellbore instability occurs, and there is a high risk of well collapse. Additionally, the formation of secondary hydrates can cause blockages in drilling tools or pipelines, compromising drilling safety. In this study, acrylamide and dimethyl diallyl ammonium chloride were used as raw materials to successfully develop a dual-effect hydrate inhibitor named ADP. The results showed that a 1% ADP concentration increased the inhibition efficiency of hydrate dissociation by approximately 21.13%. Furthermore, core immersion and linear expansion experiments using a 1% ADP solution showed that after 24 h, the core maintained its structural integrity without experiencing collapse, and the linear expansion rate decreased to 1.5%. Building upon the HEM system, this research employed the developed dual-effect hydrate inhibitor as the core component and further optimized density, rheology, filtration loss, hydration expansion inhibition, and hydrate inhibition properties to construct a high-performance water-based drilling fluid system for strong hydrate inhibition. Performance evaluation of the HTX system demonstrated excellent rheological filtration, lubrication, plugging, hydration expansion inhibition, and hydrate inhibition properties. Additionally, predictive models for drilling fluid rheological parameters under different temperature conditions were established. The research outcomes presented in this paper hold significant practical value in addressing the wellbore stability issues encountered during the drilling process of gas hydrate reservoirs in deep-sea areas.

Preparation of amphoteric polycarboxylate superplasticizer at low temperature and its application in cement-calcined kaolin blended system

As one of supplementary cementitious materials (SCMs), calcined kaolin (CK) has received increasing attention in the development of green and sustainable SCMs. When CK was applied into cement, the regular anionic polycarboxylate superplasticizer (PCE) is insufficient to disperse the cement-calcined kaolin blended system (CMT-CK system). Herein, a novel amphoteric polycarboxylate superplasticizer (VDA-1) was synthesized with hydroxybutyl vinyl polyoxyethylene ether (VPEG), acrylic acid (AA) and dimethyl diallyl ammonium chloride (DMDAAC) at low temperature (10 °C). Among a series of synthesized PCE samples, VDA-1 (nVPEG:nAA:nDMDAAC = 1:2.25:0.75) exhibits the best performance in the CMT-CK system. Results showed that the fluidity of the CMT-CK mixed slurry with VDA-1 increased by 127.9 % compared with pure CMT-CK slurry. Meanwhile, the mixed slurry with VDA-1 had good flow retention. The great fluidity of the mixed slurry with VDA-1 is attributed to that VDA-1 can be adsorbed on the surface of cement and calcined kaolin, which was demonstrated by total organic carbon (TOC) adsorption amount analysis. Besides, compared with pure CMT-CK system, the compressive and flexural strength of blended cement with VDA-1 was enhanced 2.26% and 10.60%, respectively. Split Hopkinson Pressure Bar (SHPB) test showed that the CMT-CK system containing VDA-1 exhibited large stress value before instability stage and the maximum absorption energy in the whole process.

Development of a label-free, sensitive gold nanoparticles-poly(adenine) aptasensing platform for colorimetric determination of aflatoxin B1 in corn.

In this work, a sensitive colorimetric bioassay method based on a poly(adenine) aptamer (polyA apt) and gold nanoparticles (AuNPs) was developed for the determination of aflatoxin B1 (AFB1). The polyA apt, adsorbed on the AuNPs, especially can bind to the analyte while deterring non-specific interactions. This nano aptasensor uses cationic polymer poly(diallyl dimethyl ammonium chloride) (PDDA), as an aggregating agent, to aggregate gold nanoparticles. PolyA apt-decorated gold nanoparticles (AuNPs/polyA apt) show resistance to PDDA-induced aggregation and maintains their dispersed state (red color) with the optical absorbance signal at λ = 520 nm. However, in the presence of AFB1 in the assay solution, the specific aptamer reacts with high affinity and folds into its three-dimensional form. Aggregation of AuNPs induced by PDDA caused their optical signal shift to λ = 620 nm (blue color). AFB1 concentration in the bioassay solution determines the amount of optical signal shift. Therefore, optical density ratio in two wavelengths (A620/520) can be used as a sturdy colorimetric signal to detect the concentration of aflatoxin B1. AFB1 was linearly detected between 0.5 and 20 ng mL-1, with a detection limit of 0.09 ng mL-1 (S/N = 3). The fabricated aptasensor was applied to the detection of AFB1 in real corn samples.

Self-assembly of Dawson-type H6P2W18O62@[Cu6O(TZI)3(H2O)6]4 for high-performance aerobic oxidation desulfurization of fuel.

Because global sulfur emission has escalated, the development of high-efficiency deep desulfurization techniques has become imperative. Herein, to design a high-activity heterogeneous catalyst for the aerobic oxidation desulfurization (AODS) of fuel, Dawson-type polyoxometalate (H6P2W18O62 abbreviated as D-P2W18), characterized by its high activity and strong oxidative capacity, was applied to react with CuCl2·2H2O and H3TZI via a one-pot hydrothermal method. Consequently, blue crystalline H6P2W18O62@[Cu6O(TZI)3(H2O)6]4 (abbreviated as D-P2W18@rht-MOF-1; rht-MOF-1 = [Cu6O(TZI)3(H2O)6]4·nH2O) was afforded. X-ray diffraction analysis indicated that D-P2W18 was successfully encapsulated in two different cages of rht-MOF-1, which is distinct from the crystal structure of Keggin-type POMs@rht-MOF-1. It represents the first crystal structure of Dawson-type POMs@rht-MOF-1. When D-P2W18@rht-MOF-1 was employed as a catalyst for AODS under ambient oxygen pressure with the assistance of surfactant dioctadecyl dimethyl ammonium chloride (DODMAC), it demonstrated remarkable catalytic capability and recyclability for both model fuel and commercial diesel. Further, the AODS reaction mechanism, identified as a free radical oxidation-reduction process, was verified by way of radical quenching experiments, EPR and XPS analysis. This approach offers a feasible route for the synthesis of new Dawson-type POMs@MOFs of heterogeneous catalysts for highly active AODS of fuel.

Effect of synchronous surface grafting and intercalation bentonite on properties of SBS modified bitumen

To better enhance the improvement effect of natural bentonite on the comprehensive performance of styrene-butadiene-styrene thermoplastic elastomer modified bitumen (SMB), in this study, 3-(trimethoxysilopropyl) dimethyl octadecyl ammonium chloride (DC5700) was used for synchronous surface grafting and intercalation of bentonite (DC5700-Bentonite). Meanwhile, γ-(2,3-epoxypropoxy)propytrimethoxysilane (KH560) surface grafting bentonite (KH560-Bentonite) and octadecyldimethylbenzylammonium chloride (ODBA) intercalation bentonite (ODBA-Bentonite) were used as comparison samples. The structure and properties of the bentonite and organic bentonites (DC5700-Bentonite, KH560-Bentonite and ODBA-Bentonite) were tested by X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FTIR), ultraviolet-visible spectrometer and contact angle measurement. The effects of bentonite and organic bentonites on physical, rheological and aging properties of SMB were investigated. FTIR and XRD results showed that KH560 was chemically grafted onto the surface of bentonite, ODBA was organically intercalated into the bentonite, while DC5700 achieved synchronous surface grafting and intercalation on the bentonite. Compared with KH560-Bentonite and ODBA-Bentonite, DC5700-Bentonite had the best lipophilicity and ultraviolet shielding ability. When the bentonite content was 4 wt%, KH560-Bentonite, ODBA-Bentonite and DC5700-Bentonite could increase the rutting factor of SMB by 2.9 ℃, 4.9 ℃ and 6.5 ℃, respectively, and reduce the ductility of SMB by 6.5 cm, 4.2 cm and 3.1 cm. Meanwhile, compared to SMBs containing KH560-Bentonite or ODBA-Bentonite, the SMB containing DC5700-Bentonite had the smallest creep stiffness at − 12 ℃, − 18 ℃, and − 24 ℃. The results indicated that DC5700-Bentonite was more conducive to increasing high-temperature performance of SMB than KH560-Bentonite and ODBA-Bentonite, and its adverse effects on low-temperature ductility and low-temperature cracking resistance of SMB were also significantly reduced. After thermal and ultraviolet aging, the deterioration extent of physical and rheological properties of SMB containing DC5700-Bentonite was significantly smaller than that of SMB containing KH560-Bentonite and ODBA-Bentonite. FTIR revealed that DC5700-Bentonite was more beneficial than KH560-Bentonite and ODBA-Bentonite in inhibiting the increase of carbonyl index and the decrease of butadiene index in SMB during aging. The comprehensive results revealed that compared to KH560 surface grafting bentonite and ODBA intercalation bentonite, DC5700 synchronous surface grafting and intercalation bentonite were more conducive to improving the physical and rheological properties, and aging resistance of SMB.

Effects of polymer-surfactant interactions on drag reduction performance and mechanisms: Molecular dynamics simulations and experimentation

This work provides a more favorable implementation of synergistic drag reduction strategies based on molecular simulations of the strength of polymer-surfactant interactions. The simulated preferred system identifies polyethylene oxide (PEO) and guar gum (GG) as polymers, and dodecyl dimethyl benzyl ammonium chloride (DDBAC) and dodecyl hydroxy sulfobetaine (DHSB). To forecast the drag reduction capability and identify the drag reduction process, important elements such as aggregation phenomena, charge distribution, shear deformation, and interfacial behavior were examined. Experimental measurements of viscosity, surface tension, and drag reduction validate the interactions. It was found that the compound system demonstrates enhanced viscosity, surface tension, and drag reduction efficiency compared to individual systems. The PEO-DHSB system achieves a drag reduction rate of 63.68% during initial flow, while the GG-DHSB system maintains a rate of 47.26% even after prolonged water circulation. This work visualizes the poly-surface aggregation phenomenon using the density distribution of surfactant hydrophobic tail chains, dynamically demonstrating the deformation of polymer and surfactant molecules during the shear process and interfacial behavior, and providing molecular-scale intuitive insights for understanding the drag reduction mechanism of poly-surface systems. Meanwhile, by comparing the effects of molecular type and structure on poly-surface interactions and drag reduction performance, it provides a theoretical foundation for the development and application of subsequent poly-surface drag reduction schemes, thereby broadening the application of drag reduction technology in the field of energy conservation and emission reduction.

The application of the mobile application for the assessment of cleaning workers' exposure to cleaning products: a pilot study.

Cleaning product use has been associated with adverse respiratory health effects such as asthma in cleaning staff and healthcare workers. Research in health effects from cleaning products has largely depended upon collecting exposure information by questionnaires which has limitations such as recall bias and underestimation of exposure. The aim of this study was to develop a Cleaning and Hazardous Products Exposure Logging (CHaPEL) app with a barcode scanner and to test the feasibility of this app with university cleaners. The CHaPEL app was developed to collect information on demographics, individual product information, and exposure information. It also included an ease-of-use survey. A pilot study with university cleaning workers was undertaken in which cleaning workers scanned each product after use and answered the survey. Respiratory hazards of cleaning substances in the scanned cleaning products were screened by safety data sheets, a Quantitative Structure-Activity Relationship model and an asthmagen list established by an expert group in the US. Eighteen university cleaners participated in this study over a period of 5 weeks. In total, 77 survey responses and 6 cleaning products were collected and all reported that using the app was easy. The most frequently used product was a multi-surface cleaner followed by a disinfectant. Out of 14 substances in cleaning products, ethanolamine and Alkyl (C12-16) dimethyl benzyl ammonium chloride were found as respiratory hazardous substances. The CHaPEL app is a user-friendly immediate way to successfully collect exposure information using the barcodes of cleaning products. This tool could be useful for future epidemiological studies focused on exposure assessment with less interruption to the workers.

Solar driven thermal responsive polyionic liquid/PDDA semi-IPN hydrogel for near-room temperature membrane-free osmotic desalination

The designed thermally responsive polyionic liquid (TPIL)/ poly (diallyl dimethylammonium chloride) (PDDA) hydrogel with a semi-interpenetrating (semi-IPN) structure, containing highly charged chloride anions, was fabricated to explore the comprehensive capabilities of solar driven membrane-free osmotic desalination. Introducing linear PDDA polyelectrolyte with higher charge density has effectively excluded salt ions from entering the TPIL hydrogel matrix due to the strong charge concentration gradient established between the hydrogel and the saline reservoir. Meanwhile, the thermo-sensitivity of the polyionic liquid/PDDA semi-IPN (PNCl) hydrogel enabled the release of absorbed salt-depleted water at a temperature above the Lower Critical Solution Temperature (LCST). The multiple purification process established by partial submersion of PNCl hydrogel in saline enabled continual reduction of the salt ion concentration during the upwards transportation of water along the polyelectrolyte network. Moreover, a mushroom-shaped hydrogel demonstrated enhanced the effectiveness in long-term cyclic desalination. The “mushroom cap” was loaded with photo-thermal conversion fillers (Ti3C2Tx MXene) to achieve higher photo-thermal conversion efficiency for water recovery. A record high salt rejection rate of more than 93% was obtained for membrane-free osmotic desalination. More importantly the whole desalination/water absorption/release process was solely supported by gently heating the PNCl hydrogel under the illumination of renewable solar energy.

Modification of biological starch macromolecule with phosphate and dimethylammonium chloride acyloxylate substituents confers good desizability, film properties, paste stability and adhesion

This study revealed the influence of phosphorylation-dimethylammonium chloride acyloxylation (PDACA) on the desizability, film properties, paste stability, and adhesion of biological starch macromolecules. A new starch-based sizing agent, phosphorylated-dimethylammonium chloride acyloxylated starch (PDACAS), was synthesized with degrees of substitution (DS) ranging from 0.033 to 0.065. Compared to control phosphorylated-quaternized starch (PQS, 87.4 %), the desizing efficiency of cotton yarns sized with PDACAS was ~94 %, exceeding the industrial minimum requirement of 90 %. The PDACAS film tensile properties were as follows: elongation at break of 3.31 %–3.78 %, bending endurance of 1131–1537 cycles, and tensile strength of 35.83–28.31 MPa, compared with those of acid-thinned starch (ATS) film (2.74 %, 957 cycles, and 38.12 MPa). The PDACAS had paste stability of ~92 %, compared with 83.3 % for ATS. The bonding forces (an indicator of adhesion to fibers) ranged from 107.1 N to 125.3 N for cotton roving, and 128.3 N to 148.7 N for polyester/cotton roving, which were significantly better than those of ATS (95 N for cotton and 117.9 N for polyester/cotton roving). Overall, PDACA treatment effectively avoided the adverse effect of high DS quaternization on the desizability of PQS and imparted good film properties, paste stability, and adhesion to starch.

Yolk-Shell Encapsulation of Cells by Biomimetic Mineralization and Visible Light-Induced Surface Graft Polymerization.

The pursuit of low-cytotoxicity modification strategies represents a prominent avenue in cell coating research, holding immense significance for the advancement of practical living cell-related technologies. Here, we presented a novel method to fabricate encapsulated yeast cells with a yolk-shell structure by biomimetic mineralization and visible-light-induced surface graft polymerization. In this approach, an amorphous calcium carbonate (ACC) shell was first deposited on the surface of a yeast cell (cell@ACC) modified with 4 layers of self-assembled poly(diallyl dimethylammonium chloride) (PDADMAC)/poly(acrylic acid) (PAA) film using a biomimetic mineralization technique. Subsequently, polyethylenimine (PEI) was absorbed on the surface of cell@ACC by electrostatic interaction. Then, a cross-linked shell was introduced by surface-initiated graft polymerization of poly(ethylene glycol) diacrylate (PEGDA) on cell@ACC under irradiation of visible light using thioxanthone catechol-O,O'-diacetic acid as the photosensitizer. After the removal of the inner ACC shell, the yolk-shell-structured yeast cells (cell@PHS) were obtained. Due to the mild conditions of the strategy, the cell@PHS could retain 98.81% of its original viability. The introduction of the shell layer significantly prolonged the lag phase of yeast cells, which could be tuned between 5 and 25 h by regulating the thickness of the shell. Moreover, the cell@PHS showed improved resistance against lyticase due to the presence of a protective shell. After 30 days of storage, the viability of cell@PHS was 81.09%, which is significantly higher than the 19.89% viability of native yeast cells.

A Study on the Removal Characteristics and Mechanism of Phosphorus from Simulated Wastewater Using a Novel Modified Red-Mud-Based Adsorption Material

In this work, a common third-generation environmentally friendly quaternary ammonium salt disinfectant, dimethyl dioctadecyl ammonium chloride (DDAC), was used as the modifier to achieve one-step rapid preparation of the modified red-mud-based adsorption material under the condition of microwave assistance, and applied it to the adsorption phosphorus in solutions. After the process of this modification, the structure of the red mud (RM) was not changed, and the DDAC modification could provide more adsorption active sites. The adsorption experiments indicated that the novel modified red mud (NMRM) exhibited a good adsorption performance for phosphorus. The adsorption capability of NMRM for phosphorus was significantly enhanced, and was about eight times higher than that of the initial RM. The kinetics model of the pseudo-second-order, which implied that phosphorus was chemically adsorbed on the surface of the NMRM, could accurately represent the adsorption procedure of NMRM. The adsorption equilibrium of NMRM could be better depicted using the isotherm model of Freundlich. It was speculated that the ion exchange might be responsible for the adsorption mechanism of NMRM for phosphorus. Thus, the NMRM is a potential material for the treatment of phosphorus-containing wastewater due to its outstanding adsorption capability.

Conductive passivating contact for high fill factor monolithic perovskite/silicon tandem solar cells

AbstractPerovskite/silicon tandem solar cells (PK/Si TSCs) blaze the way in pushing power conversion efficiency (PCE) beyond the single‐junction Shockley–Queisser limit. Meanwhile, localized defects in perovskite subcells result in a lower fill factor (FF), which limits further improvement of PCE in PK/Si TSCs. Herein, we report a conductive passivation contact layer by posttreatment of bis(2‐hydroxyethyl)dimethylammonium chloride (BDAC) zwitterion molecule on the perovskite surface. It can passivate the positive and negative localized defects, inhibit the formation of Pb0, and spontaneously convert the perovskite surface to be a more n‐type conductive contact layer for charge separation. These combined enhancements enabled a PCE of 21.4% with an enhanced VOC of 80 mV and an FF of 82.84% for the inverted single‐junction device prepared by the two‐step method. Moreover, BDAC passivation achieved a PCE of 28.67% with an FF of 80.02% for PK/Si TSCs. In addition, the scaling‐up device with an active area of 11.879 cm2 delivers a PCE of 24.46%, and a minimodule with power conversion over 2 W is designed and fabricated.

Recombinant VAR2CSA malaria protein-targeted exosome-mediated DACT2 gene therapy for effective glioma treatment

A good non-viral vector is the key to the success of gene delivery and therapy; hence, modified exosomes may overcome the physiological barrier in the delivery in vivo. This study aims to design a novel non-viral vector and verify its gene delivery function in vitro and in vivo for dapper homolog 2 (DACT2) genes. In this study, amphipathicity cationic exosomes with receptor targeted function and DACT2 gene loading function were constructed by exosomes, PEG, glycidyl hexadecyl dimethylammonium chloride, and recombinant VAR2CSA malaria protein (RVP) antibody. Characterizations of RVP antibody and PEG modified cationic lipid exosome (RVP-CL) nanocomplexes were evaluated by dynamic light scattering, atomic force microscopy, FTIR, and so on. The DNA condensation ability and stability were assessed by agarose gel electrophoresis. Cellular uptake efficiency and cytotoxicity in glioma cells were investigated. Furthermore, the tumor suppressive effect was evaluated in vitro and in vivo. The results indicated that RVP-CL had a uniform size of 100–200 nm and positive zeta potential. With high uptake efficiency, RVP-CL can rapidly target, recognize, and enter the glioma cell (KNS-42 and U118 mg) and release the gene. Moreover, RVP-CL/DACT2 can effectively inhibit the growth of glioma cells in vitro and in vivo. The modified cationic exosomes may offer a promising strategy for gene delivery in the treatment of RVP-positive gliomas or other tumors.