Alkali Environment Research Articles

Bioactive Calcium Hydride-Driving "Triple" Hydrogen/Alkaline/Calcium Therapy for Efficient Treatment of Osteomyelitis.

Osteomyelitis with high mortality and disability rates is a common clinical disease caused by a bacterial infection that is difficult to cure. Considering the stubborn nature and depth of tissue infection, rapid and effective treatments for osteomyelitis remain an enormous challenge. Calcium hydride (CaH2), as efficient hydrogen/alkaline/calcium donors, is employed for combined osteomyelitis therapy. CaH2 reacts with water to sufficiently generate a strong alkali environment with hydroxide anions (OH-) to inhibit bacterial proliferation and induce bacterial death. The released calcium ions (Ca2+) induce calcium overload to kill bacteria first and then serves as calcium source to promote new bone formation. Another byproduct, hydrogen enhances the bacterial membrane permeability and scavenges excess reactive oxygen species (ROS). After incubation with bacteria, CaH2 significantly increases the permeability of the bacterial membrane, therefore increasing the entry of OH- and Ca2+ into bacterial cells, thereby leading to significant bacterial death. After being applied to S. aureus-infected mouse tibia osteomyelitis, CaH2 materials efficiently kill bacteria, relieve local inflammation, and promote new bone formation in a short time. Overall, bioactive metal hydride-associated "triple" hydrogen/alkaline/calcium therapy provides a new idea for the treatment of deep-site bacterial infection, which is beneficial for relieving the pressure caused by antibiotic-resistant bacteria.

Enhancing alkali resistance of recycled GFRP fibers and mechanical performances of cement mortars with microbial induced carbonate precipitation

Applying the recycled glass fiber reinforced plastic (rGFRP) fiber to reinforce cement-based materials is a promising way to reuse this massively waste material. However, rGFRP fiber is prone to be corroded in the alkali environment of cement. To solve this problem, the rGFRP fiber was treated with microbial induced CaCO3 precipitation (MICP) technique. The effects of MICP treatment on the rGFRP fiber and the reinforced mortar were investigated. It was revealed that the alkali resistance of the rGFRP fiber was significantly modified by CaCO3 deposition, which was increased with the concentration of mineralizing solution and treating time. The tensile strength and aging resistance of the rGFRP fiber reinforced mortar were all improved by MICP treatment, since fiber-cement friction, fiber-cement compatibility, microstructural compactness and cement hydration degree were enhanced by the properly precipitated CaCO3 crystals on fiber surface. However, excessive MICP treating process was detrimental for effective CaCO3 precipitation. The rGFRP fiber treated in the mineralizing solution of 1.0 mol/L for 3 times with 24 h/time (1−24−3) had the most promising modification effect on the rGFRP fiber and the reinforced mortar in this study. The 1–24–3 rGFRP fiber had similar alkali resistance to the alkali resistance glass fiber, which increased the tensile strength of mortar by 34.1 % and improved the bending strength of mortar by 10.8 % after accelerated aging. The MICP technique was used on modifying rGFRP fiber and the reinforced mortar for the first time, which would benefit the durability of rGFRP fiber and its wider application in cement-based materials, while the long-term performance of rGFRP fiber reinforced mortar should be studied in the future.

The flexural strength of high-ductile concrete in saline-alkali area

Sulfate corrosion is an important cause of accelerated structural failure in concrete structures in coastal and saline alkali areas. High ductility concrete has good tensile and durability properties, and is therefore widely used for the repair and reinforcement of damaged structures. To investigate the flexural performance of high ductility concrete on ordinary concrete structures in saline alkali environments, experimental methods were used to test it. The experimental data validated that the bearing capacity of the 10 mm specimen reinforced with high ductility concrete before and after corrosion is 125 kN and 117 k, respectively. After reinforcement and corrosion, the bearing capacities of the specimens were 115 kN, 129 kN, and 139 kN, respectively. In addition, sodium sulfate reduced the deformation capacity of the original specimen by 13.9 %, but after reinforcement, the deformation capacity of the specimen increased by at least 97.1 %. Compared to reinforced specimens in non saline alkali environments, the deformation capacity of reinforced specimens in saline alkali environments decreases by no more than 23 %. Compared to unreinforced specimens, the strain capacity of reinforced concrete and longitudinal bars in sulfate environments increased by at least 28.1 % and 34.5 %, respectively. However, compared to reinforced specimens in conventional environments, the strain capacity of reinforced specimens in sulfate environments decreased by no more than 19 %. The above results indicate that high ductility concrete can effectively improve the bending resistance of specimens, while also slowing down the corrosion of sulfates on specimens and effectively extending the service life of concrete structures.

Molten Alkali-Assisted Formation of Silicate Gels and Its Application for Preparing Zeolites.

Fly ash was used as raw material to prepare zeolites through silicate gels, assisted by the hydrothermal method. The silicate gels could be effectively formed in a few minutes in a molten alkali environment. The zeolites could be prepared by using these silicate gels through the hydrothermal method, which realizes the transformation from useless materials to highly valuable materials. The obtained zeolites were applied to the removal of ammonium in water, achieving the highvalue utilization of fly ash. The synthesized zeolites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrum (EDS), thermogravimetric (TG), and Fourier transform infrared (FTIR) spectroscopy. The study on the adsorption and removal of ammonium in water shows that the adsorption of ammonium is more in line with pseudo first-order kinetics, and the adsorption mainly occurs in the first 20 min. The adsorption can reach equilibrium in 30 min, and the maximum adsorption capacity can reach 49.1 mg/g. The adsorption capacity of ammonium has the best performance at pH = 5. Furthermore, within a certain range, an increase in temperature is beneficial for the removal of ammonium.

A low-friction and high-stability hydrophilic PVP/PEG coated TPU for interventional catheter applications

Vascular interventional catheters are generally made of hydrophobic polymers, which may lead to vascular injury, poor lubrication and other consequences due to friction with vascular wall or stent in the process of intervention. In this study, the PDA-PVP/PEG composite coating was prepared based on common TPU catheter material to improve its hydrophilic lubrication behavior. Firstly, the oxidative self-polymerization of dopamine (PDA) was initiated and deposited on the surface of TPU in a weak alkali environment, and then the PVP/PEG coating was prepared by UV curing with PDA as the intermediate adhesion layer. The composite coating was optimized step by step by lubricating material system, process parameters, molecular weight, and concentration. Compared with the blank control group, the water contact angle decreased from 91.3° to about 28.3°, and the friction coefficient decreased from 0.4 to about 0.03, and the composite coating was not damaged after 30 min of reciprocating sliding. The results of cytotoxicity grade Level 1 and hemolysis rate less than 5 % also proved that the composite coating showed good cytotoxicity and blood compatibility. In summary, the PDA-PVP/PEG hydrophilic lubricating composite coating revealed excellent comprehensive properties.

Iris typhifolia Responses to Saline–Alkali Stress: Germination, Antioxidant Activity, Hormones, and Photosynthetic Performance

Iris typhifolia Kitag is a perennial herbaceous species with high ornamental and applied value. Elucidating the mechanism of saline–alkali tolerance in Iris is crucial for their promotion in saline–alkali areas. Saline–alkali stress is one of the factors that affects plant growth, which has become a significant global issue. In this study, we measured the physiological and biochemical indexes of I. typhifolia, through germination and potting trials, to evaluate the resistance of I. typhifolia to different levels of artificial saline–alkali stress (0, 50, 100, 150, and 200 mmol·L−1). The results showed that artificial saline–alkali stress negatively impacted germination parameters, cell membrane integrity, and photosynthetic parameters. Different trends in osmoregulatory substances and endogenous hormones were observed. It was shown that I. typhifolia had a potential adaptability to the saline–alkali environment by enhancing its internal defense mechanism. Based on regression analyses, the germination threshold of I. typhifolia was calculated to be 87.15 mmol·L−1, which provided a theoretical basis for the application in soil saline–alkalization areas.

Aging behaviour assessment of cellulosic fibres in alkaline media: A green technology approach in construction materials

With the increasing demand for buildings, the utilisation of green materials represents a novel approach toward achieving sustainable development goals. Cellulose-based materials, such as jute, exemplify eco-friendly substances for civil engineering applications. The present study aims at studying the aging behavior of jute fibers in an alkaline environment. For this purpose, three alkali environments (NaOH, KOH, Ca(OH)2) with three different concentrations were selected. Samples were treated at three different periods (7 d, 14 d, and 28 d) to assess the impact of treatment on the fiber properties. This study introduces a pioneering concept of the alkali treatment of jute-based fibres to evaluate tensile strength and weight loss, marking the first of its kind. This approach incorporates various characterisation techniques, including Differential Scanning Calorimetry (DSC), Thermo-Gravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM) to assess the treatment process. In our experimental procedures, we evaluated key parameters such as the type of alkali, alkali concentration, and curing time for their influence on tensile strength. Subsequently, we applied Response Surface Methodology (RSM) in conjunction with bagging techniques to develop mathematical models based on the acquired data. Results demonstrated varied tensile strengths based on alkali type, concentration, and treatment duration. Fibres treated with 15 g/L concentration of NaOH exhibited an increase in tensile strength from 7 days (79.66 MPa) to 28 days (225.05 MPa). The highest tensile strength of jute fibres treated with KOH was observed with 15 g/L concentration at 14 days (237.58 MPa). For Ca(OH)₂ treatments, the highest tensile strength was observed with 30 g/L concentration at 14 days (111.28 MPa). It was also observed that prolonged exposure to very high alkali concentrations could adversely affect the tensile strength, as observed in the case of 30 g/L concentration of NaOH at 28 days (84.73 MPa). Among the various alkali materials tested, NaOH and KOH demonstrated greater effectiveness compared to Ca(OH)2. According to RSM analysis, the time of sample curing was found to be the most significant factor in tensile strength, with a P-value of 0.009. On average, the tensile strength changes by 54 %, 52 %, and 35 % for NaOH, KOH, and Ca(OH)₂, respectively, when the curing time shifts from 7 days to 28 days.

Catalytic activity of Ni–Cr–Fe–Mo porous materials for hydrogen evolution reaction in alkaline media

The hydrogen evolution reaction (HER) based on water electrolysis represents an ideal approach for hydrogen production. The advancement of highly active non-precious metal catalysts holds paramount importance. This research employed powder metallurgy sintering to prepare Ni–Cr–Fe and Ni–Cr–Fe–Mo porous materials. It investigated the impact of Mo doping and sintering temperature on the catalytic activity and microstructural influence of hydrogen evolution materials. Furthermore, the materials' electrochemical performance and long-term stability in 6 mol/L KOH were examined. In complicated systems, the current work provides a feasible method for producing hydrogen from Ni–Cr–Fe–Mo porous materials in a strong alkali environment. The results exhibited that when Mo content is 5% and the sintering temperature is 800 °C, the porosity of Ni–Cr–Fe–Mo porous materials is up to 39.9% and the catalytic activity is up to 97%. At the same time, the current density decays to 7.1% after 1000 cycles of electrolysis and shows good HER stability after 48 h. The enhanced catalytic activity for hydrogen evolution emanated from the positive synergy among the transition metal elements.

Understanding the stability behavior of colloidal silica in different alkali environments

Understanding the stability behavior of colloidal silica in different alkali environments

Experimental Study of a Superabsorbent Polymer Hydrogel in an Alkali Environment and Its Effects on the Mechanical and Shrinkage Properties of Cement Mortars.

As internal curing self-healing agents in concrete repair, the basic properties of superabsorbent polymers (SAPs), such as water absorption and release properties, are generally affected by several factors, including temperature and humidity solution properties and SAP particle size, which regulate the curing effect and the durability of cementitious composites. This study aimed to investigate the water retention capacities of SAPs in an alkaline environment over extended periods by incorporating liquid sodium silicate (SS) into SAP-water mixtures and examining the influence of temperature. The influence of SAP particle size on mortar's water absorption capacity and mechanical behavior was investigated. Two mixing techniques for SAPs (dry and pre-wetting) were employed to assess the influence of SAP on cement mortars' slump, mechanical properties, and cracking resistance. Four types of SAPs (SAP-a, SAP-b, SAP-c, and SAP-d), based on the molecular chains and particle size, were mixed with SS to study their water absorption over 30 days. The results showed that SAPs exhibit rapid water absorption within the first 30 min, exceeding 85% before reaching a saturation point, and the chemical and temperature variations in the water significantly affected water absorption and desorption. The filtration results revealed that SAP-d exhibited the slowest water release rate, retaining water for considerably longer than the other three types of SAPs. The mechanical properties of SAP mortar were reduced due to the addition of an SAP and the improved cracking resistance of the cement mortars.

Argon non-thermal plasma treatment promotes the development of rice (Oryza sativa L.) in saline alkali environments.

Soil salinization leads to a reduction in arable land area, which seriously endangers food security. Developing saline-alkali land has become a key measure to address the contradiction between population growth and limited arable land. Rice is the most important global food crop, feeding half of the world's population and making it a suitable choice for planting on saline-alkali lands. The traditional salt-alkali improvement method has several drawbacks. Currently, non-thermal plasma (NTP) technology is being increasingly applied in agriculture. However, there are few reports on the cultivation of salt/alkali-tolerant rice. Under alkaline stress, argon NTP treatment significantly increased the germination rate of Longdao 5 (LD5) rice seeds. In addition, at 15kV and 120s, NTP treatment significantly increased the activity of antioxidant enzymes such as catalase and SOD. NTP treatment induced changes in genes related to salt-alkali stress in rice seedlings, such as chitinase and xylanase inhibitor proteins, which increased the tolerance of the seeds to salt-alkali stress. This experiment has expanded the application scope of NTP in agriculture, providing a more cost-effective, less harmful, and faster method for developing salt-alkali-tolerant rice and laying a theoretical foundation for cultivating NTP-enhanced salt-alkali-tolerant rice.

Transcriptomics and Metabolomics Analysis Revealed the Ability of Microbacterium ginsengiterrae S4 to Enhance the Saline-Alkali Tolerance of Rice (Oryza sativa L.) Seedlings

Soil salinization is a major factor that reduces crop yields. There are some plant growth-promoting rhizobacteria (PGPR) that can stimulate and enhance the salt tolerance of plants near their roots in saline–alkali environments. Currently, there is relatively little research on PGPR in rice saline–alkali tolerance. In the early stages of this study, a strain of Microbacterium ginsengiterrae S4 was screened that could enhance the growth of rice in a laboratory-simulated saline–alkali environment (100 mM NaCl, pH 8.5). The experiment investigated the effects of S4 bacteria on the growth, antioxidant capacity, and osmotic regulation of rice seedlings under saline–alkali stress. RNA-Seq technology was used for transcriptome sequencing and UPLC-MS/MS for metabolite detection. Research has shown that S4 bacteria affect the growth of rice seedlings under saline–alkali stress through the following aspects. First, S4 bacteria increase the antioxidant enzyme activity (SOD, POD, and CAT) of rice seedlings under saline–alkali stress, reduce the content of MDA, and balance the content of osmotic regulatory substances (soluble sugar, soluble protein, and proline). Second, under saline–alkali stress, treatment with S4 bacteria caused changes in differentially expressed genes (DEGs) (7 upregulated, 15 downregulated) and differentially metabolized metabolites (101 upregulated; 26 downregulated) in rice seedlings. The DEGs are mainly involved in UDP-glucose transmembrane transporter activity, while the differentially metabolized metabolites are mainly involved in the ABC transporters pathway. Finally, key genes and metabolites were identified through correlation analysis of transcriptomes and metabolomes, among which OsSTAR2 negatively regulates L-histidine, leading to an increase in L-histidine content. Furthermore, through gene correlation and metabolite correlation analysis, it was found that OsWRKY76 regulates the expression of OsSTAR2 and that L-histidine also causes an increase in 2-methyl-4-pentenoic acid content. Based on the above analysis, the addition of S4 bacteria can significantly improve the tolerance of rice in saline–alkali environments, which has a great application value for planting rice in these environments.

Physiological and Biochemical Responses of Melilotus albus to Saline and Alkaline Stresses

Sweet clover (Melilotus albus) is a high-quality leguminous forage grass with salinity tolerance, drought tolerance, and cold hardiness. We selected four varieties of sweet clover with different sensitivities (061898, 061930, No. 55 white flower, and Ningxia white flower) and analyzed the effects of different concentrations of three sodium salts (Na2CO3, NaHCO3, and NaCl) on their physiology and biochemistry responses. Growth and development indexes (such as germination rate, root length, shoot length), chlorophyll content, osmotic regulators (proline, soluble sugar), malondialdehyde (MDA), superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were determined under saline–alkali stress. Seed germination and seedling growth of all four clover species were significantly inhibited under saline–alkali stress. During germination, seed germination rate, root length, and shoot length decreased with increasing saline and alkaline concentration. Under saline–alkali stress, chlorophyll content tended to increase and then decrease, cell damage and death increased, and malondialdehyde, soluble sugar, and proline content tended to increase and then decrease. Moreover, the activities of SOD, POD, and CAT all increased and then decreased. Under Na2CO3 stress, the decrease in chlorophyll content of the resistant variety 061898 was less than in the sensitive Ningxia white flower variety. As the concentrations of Na2CO3, NaHCO3, and NaCl increased, the maximum photochemical efficiency of PSII was significantly affected. The resistant 061898 is capable of maintaining higher photosynthetic efficiency. Furthermore, under treatments with the three kinds of saline–alkali solutions, cell damage and death for Ningxia white flower were greater than in 061898. For 061898, the increases in soluble sugar and proline content were greater and the increase in malondialdehyde content was less, while the antioxidant enzyme activities were higher than those in Ningxia white flower. All four sweet clover varieties had higher stress resistance with neutral than with alkaline salts. When stressed by medium to high saline–alkali concentrations, sweet clover seedlings had increased osmotic substance content, enhanced antioxidant enzyme activity, and regulated physiological metabolism. Additionally, sweet clovers regulated the expression of WRKY33, GH3, CYCD3, OXI1, MKK2, MYC2, JAZ, COI1, PYL, PP2C, TGA, and MPK3 to adapt to the saline–alkali environment and improve saline–alkali tolerance. Our analysis of the sweet clover salinity tolerance mechanism contributes to its further use and is of significant importance for addressing land salinization and promoting sustainable agricultural and pastoral practices in China.

A Robust HPLC Approach for Quantitation of Camptothecin in Mesoporous Silica Nanoparticles Matrix and in the Presence of Its Degradation Products.

Camptothecin is a potent anticancer drug used for the treatment of various cancers. The goal of this research investigation was to develop and validate a new stability-indicating HPLC technique for the quantitative assessment of camptothecin in in-house developed mesoporous silica nanoparticles, a novel nanoformulation matrix for the treatment of cancer. The Waters Inertsil® HPLC column (C18) was used for the chromatographic separation, with a flow rate of 1 mL/min, a column oven temperature of 40°C, an injection volume of 10 µL, a detection wavelength of 216 nm, and a 10 min runtime overall. An isocratic blend of phosphate buffer (10 mM, pH7.0) and acetonitrile (60:40, v/v) served as the mobile phase. Various stress conditions including acid, alkali, oxidative, photolytic, thermal, and humidity environments were tested for the quantitative estimation of the camptothecin through the proposed method. The results demonstrated that the proposed method is specific (peak purity ≥0.999), accurate (99.69-100.64% w/w), precise (RSD, % <2.0), and sensitive (LOD-0.17 µg and LOQ-0.56 µg) in accordance with ICH guideline Q2 (R1). Any unidentified degradation products did not interfere with the drug's estimation. Furthermore, the current method of analysis has eliminated any excipient interference from the matrix effect caused by the numerous excipients of the formulation matrix. To quantify camptothecin for routine assay purposes, this research work offers a novel and straightforward HPLC methodology with optimized chromatographic parameters, contributing to the research and development community while ensuring an appropriate and efficient use of the drug through a variety of nanoformulation for cancer treatment. The stability-indicating HPLC method was found to be specific and suitable for routine analysis of camptothecin. The absence of any interference from excipients was confirmed by forced degradation studies.

Construction potential of rice husk ash as eco-friendly cementitious material in a low-water demand for self-compacting concrete

Self-compacting concrete (SCC) is a special mix design that offers advantages, such as high flowability and better compaction. Combining it with natural pozzolans through partial replacement influences considerably the filling and passing abilities, and segregation resistance, while generating high-strength performance. A low water-to-binder ratio (w/b) leads to a dense, non-porous, and durable SCC, but its desired workability is difficult to obtain. Hence, the addition of chemical admixtures, such as superplasticizers (SP) and air-entraining agents (AEA) may resolve this issue. Moreover, the incorporation of rice husk ash (RHA) as supplementary cementitious material (SCM) in an alkali environment promotes enhanced stability and workability, as well as avoiding any bleeding or segregation problems. RHA also improves the concrete’s microstructure owing to its highly reactive fine silica. However, there is limited evidence reported on the effects of RHA on SCC’s overall flowability, pozzolanic reactions, and microstructural analyses. Here the synergistic effects of RHA on the rheological performance, strength development, pozzolanic activities, and microstructural characterization of fresh and hardened SCC were reported. The study showed that while the filling ability, passing ability, and segregation resistance of fresh mixture all conform to the threshold values, the recorded compressive strength of the hardened samples was highest in SC-09 at 90-day cured samples. The mix proportion of this sample includes a low w/b ratio of 0.35 and 15% RHA replacement, with optimized rheological performance and pozzolanic activities. It was observed in the sample’s microstructure that the silica particles chemically reacted with CH, promoting CSH gel products. The disappearance of dicalcium silicate (C2S) and tricalcium silicate (C3S) in diffractograms was observed and replaced by CSH gel, which plays a key role in strength formation. IR spectral bands at ∼765 and ∼464 cm−1 indicated the amorphous silica phase of the RHA-SCC samples, while the spectral band relation of RHA and the samples showed a high degree of reaction of RHA upon mixing. The surface morphology images proved a highly dense matrix in 15% RHA replacement. Observed pores and cracks were lessen compared to samples with 0–10% RHA, which verified the construction potential of RHA in an optimized amount. While the sulfate and seawater performance tests indicated a low mass loss and high relative strength occurred to samples with 15% RHA replacement when immersed to both solutions, signifying that the addition of RHA in concrete leads to better chemical attack resistance compared to OPC alone due to the highly reactive silica of RHA.

Comparative transcriptome analysis reveals the adaptive mechanisms of halophyte Suaeda dendroides encountering high saline environment.

Suaeda dendroides, a succulent euhalophyte of the Chenopodiaceae family, intermittently spread around northern Xinjiang, China, has the ability to grow and develop in saline and alkali environments. The objective of this study was therefore to investigate the underlying molecular mechanisms of S. dendroides response to high salt conditions. 27 sequencing libraries prepared from low salt (200 mM NaCl) and high salt (800 mM NaCl) treated plants at 5 different stages were sequenced using Illumina Hiseq 2000. A total of 133,107 unigenes were obtained, of which 4,758 were DEGs. The number of DEGs in the high salt group (3,189) was more than the low salt treatment group (733) compared with the control. GO and KEGG analysis of the DEGs at different time points of the high salt treatment group showed that the genes related to cell wall biosynthesis and modification, plant hormone signal transduction, ion homeostasis, organic osmolyte accumulation, and reactive oxygen species (ROS) detoxification were significantly expressed, which indicated that these could be the main mechanisms of S. dendroides acclimate to high salt stress. The study provides a new perspective for understanding the molecular mechanisms of halophytes adapting to high salinity. It also provides a basis for future investigations of key salt-responsive genes in S. dendroides.

Electrostatically self-assembled three-dimensional conductive network for highly sensitive and reliable skin-like strain sensor

In recent years, flexible strain sensors have garnered significant attention in industrial manufacturing and daily life. Sensitivity and reliability are two crucial characteristics of flexible strain sensors in practical applications, and they depend on the development of the sensor's internal conductive network. However, the aggregation phenomenon of conductive fillers in the elastic matrix has a serious impact on the construction of a developed conductive network. In this work, we have designed electropositive amino-functionalized carbon nanotubes (CNTs-p) based on the electrostatic self-assembly of electronegative MXene in the aqueous phase. Compared to the use of surfactants, the electrical modulation of carbon nanotubes through chemical bonding modification is more robust and the electrostatic self-assembly with MXene is more stable. CNTs-p and MXene were self-assembled by electrostatic attraction in butyl latex and uniformly dispersed in the latex. Following demulsification, the polymer composite film (MXene&CNTs-p/IIR) with a three-dimensional conductive network was obtained. The skin-like strain sensor, which utilizes the conductive composite film, demonstrates high sensitivity (gauge factor (GF) = 35137 that is among the highest values for the reported strain sensor), remarkable reliability (The signal monitoring capability remains after 15000 cycles), and excellent responsiveness (62 ms). Additionally, the skin-like strain sensor boasts a wide detection range (0–431%) and unprecedented stability, enabling strain sensing functionality in a wide temperature range of -10—100 °C, as well as strong acid (pH = 1) and strong alkali (pH = 11) environment. The preparation of MXene&CNTs-p/IIR provides a safe, environmentally friendly and effective method for improving the sensitivity and reliability of flexible sensors in wearable intelligent electronics and health detection.

Study on the influence of different acid and alkali environments on the spontaneous combustion properties of coal

To examine the impacts of diverse acid and alkali environments on the autothermal oxidation characteristics of coal, the microporous structure, active functional groups and oxidative thermodynamic parameters were investigated using SEM, TG-DSC and FTIR experimental methods. The results show that the number of pores on the eroded coal increases and the pore size increases compared to the neutral environment of pH = 7. The content of major oxygenated functional groups decreases and is converted to more reactive oxygenated alkali metal structures, with an approximate reduction of 35 % for ketone carbonyl CO and 57 % for acid carboxylic acid CO at pH = 10. The acidic environment promotes the combination of hydroxyl-hydrogen bonding functional groups with oxygen. The reactive exothermic process of eroded coal was promoted in pH = 4, 6, 8, and 10, and the combustion-promoting effect on NMG was more obvious, in which the ignition point temperature T6 of HG was reduced by 7.6 °C, 5.9 °C, 8.2 °C, and 5.1 °C, respectively. During the fitting process using the model-free method, the best fit for the oxygen uptake and weight gain stage and the combustion pyrolysis stage was achieved by the KAS and Friedman methods, respectively, and efficient fire extinguishing could be achieved in the pre-combustion pyrolysis stage (0.1<α < 0.2).

Plectasin: from evolution to truncation, expression, and better druggability.

Non-computational classical evolution analysis of plectasin and its functional relatives can especially contribute tool value during access to meet requirements for their better druggability in clinical use. Staphylococcus aureus is a zoonotic pathogen that can infect the skin, blood, and other tissues of humans and animals. The impact of pathogens on humans is exacerbated by the crisis of drug resistance caused by the misuse of antibiotics. In this study, we analyzed the evolution of anti-Staphylococcus target functional sequences, designed a series of plectasin derivatives by truncation, and recombinantly expressed them in Pichia pastoris X-33, from which the best recombinant Ple-AB was selected for the druggability study. The amount of total protein reached 2.9 g/L following 120 h of high-density expression in a 5-L fermenter. Ple-AB was found to have good bactericidal activity against gram-positive bacteria, with minimum inhibitory concentration (MIC) values ranging between 2 and 16 μg/mL. It showed good stability and maintained its bactericidal activity during high temperatures, strong acid and alkali environments. Notably, Ple-AB exhibited better druggability, including excellent trypsin resistance, and still possessed approximately 50% of its initial activity following exposure to simulated intestinal fluids for 1 h. In vitro safety testing of Ple-AB revealed low hemolytic activity against mouse erythrocytes and cytotoxicity against murine-derived macrophages. This study successfully realized the high expression of a new antimicrobial peptide (AMP), Ple-AB, in P. pastoris and the establishment of its oral administration as an additive form with high trypsin resistance; the study also revealed its antibacterial properties, indicating that truncation design is a valuable tool for improving druggability and that the candidate Ple-AB may be a novel promising antimicrobial agent.

Stereoselective synthesis of (R)-(+)−1-(1-naphthyl)ethylamine by ω-amine transaminase immobilized on amino modified multi-walled carbon nanotubes and biocatalyst recycling

Immobilized enzymes exhibit favorable advantages in biocatalysis, such as high operation stability, feasible reusability, and improved organic solvents tolerance. Herein, an immobilized ω-amine transaminase AtATA@MWCNTs-NH2 is successfully prepared using amino modified multi-walled carbon nanotubes as carrier and glutaraldehyde as crosslinker. Under the optimum immobilization conditions, the activity recovery is 78.7%. Compared with purified enzyme AtATA, AtATA@MWCNTs-NH2 possesses superior stability, even in harsh conditions (e.g., high temperature, acidic or alkali environment, and different kind of organic solvents). To simplify the separation and extraction of products, we choose methanol (10%, v/v) as the cosolvent, replacing DMSO (20%, v/v) in our previous work, for the catalytic reaction of AtATA@MWCNTs-NH2. AtATA@MWCNTs-NH2 can be used for stereoselective synthesis (R)-(+)− 1(1-naphthyl)ethylamine ((R)-NEA) for 15 cycles, with the e.e.p (enantiomeric excess) > 99.5%. The catalytic process of AtATA@MWCNTs-NH2 achieves cycle production of (R)-NEA using methanol as cosolvent.