Ultra-Low Loading of Ultra-Small Fe3 O4 Nanoparticles on Nonmodified CNTs to Improve Green EMI Shielding Capability of Rubber Composites

From a material design perspective, the incorporation of Fe3 O4 @carbon nanotube (Fe3 O4 @CNT) hybrids is an effective approach for reconciling the contradictions of high shielding and low reflection coefficients, enabling the fabrication of green shielding materials and reducing the secondary electromagnetic wave pollution. However, the installation of Fe3 O4 nanoparticles on nonmodified and nondestructive CNT walls remains a formidable challenge. Herein, a novel strategy for fabricating the above-mentioned Fe3 O4 @CNTs and subsequently assembling segregated Fe3 O4 @CNT networks in natural rubber (NR) matrices is proposed. The advanced and unique structure, magnetism, and lossless conductivity endow the as-obtained Fe3 O4 @CNT/NR with a shielding effectiveness (SE) of 63.8 dB and a low reflection coefficient of 0.24, which indicates a prominent green-shielding capability that surpasses those of previously reported green-shielding materials. Moreover, the specific SE reaches 531 dB cm-1 , exceeding that of those of previously reported carbon/polymer composites. Meanwhile, the outstanding conductivity enables the composite to reach a saturation temperature of ≈95 °C at a driving voltage of 1.5 V with long-term stability. Therefore, the as-fabricated Fe3 O4 @CNT/rubber composites represent an important development in green-shielding materials that are applied in cold environment.

Accurate assembly of thiophene-bridged titanium-oxo clusters with photocatalytic amine oxidation activity

Designing and synthesizing well-defined crystalline catalysts for the photocatalytic oxidative coupling of amines to imines remains a great challenge. In this work, a crystalline dumbbell-shaped titanium oxo cluster, [Ti10O6(Thdc)(Dmg)2(iPrO)22] (Ti10, Thdc = 2,5-thiophenedicarboxylic acid, Dmg = dimethylglyoxime, iPrOH = isopropanol), was constructed through a facile one-pot solvothermal strategy and treated as a catalyst for the photocatalytic oxidative coupling of amines. In this structure, Thdc serves as the horizontal bar, while the {Ti5Dmg} layers on each side act as the weight plates. The molecular structure, light absorption, and photoelectrochemical properties of Ti10 were systematically investigated. Remarkably, the inclusion of the Thdc ligand, with the assistance of the Dmg ligand, broadens the light absorption spectrum of Ti10, extending it into the visible range. Furthermore, the effective enhancement of charge transfer within the Ti10 was achieved with the successful incorporation of the Thdc ligand, as opposed to PTC-211, where terephthalic acid replaces the Thdc ligand, while maintaining consistency in other aspects of Ti10. Building on this foundation, Ti10 was employed as a heterogeneous molecular photocatalyst for the catalytic oxidative coupling reaction of benzylamine (BA), demonstrating very high conversion activity and selectivity. Our study illustrates that the inclusion of ligands derived from Thdc enhances the efficiency of charge transfer in functionalized photocatalysts, significantly influencing the performance of photocatalytic organic conversion.

Heterologous Expression and Characterization of a Novel Mesophilic Maltogenic α-Amylase AmyFlA from Flavobacterium sp. NAU1659

A novel amylase AmyFlA from Flavobacterium sp. NAU1659, AmyFlA, was cloned and expressed in Esherichia coli. Based on phylogenetic and functional analysis, it was identified as a novel member of the subfamily GH13_46, sharing high sequence identity. The protein was predicted to consist of 620 amino acids, with a putative signal peptide of 25 amino acids. The enzyme was able to hydrolyze soluble starch with a specific activity of 352.97 U/mg at 50 °C in 50 mM phosphate buffer (pH 6.0). The Km and Vmax values of AmyFlA were respectively 3.15 mg/ml and 566.36 µmol·ml-1·min-1 under optimal conditions. Its activity towards starch was enhanced by 63% in the presence of 1 mM Ca2+, indicating that AmyFlA was a Ca2+-dependent amylase. Compared to the reported maltogenic amylases, AmyFlA produced a lower variety of intermediate oligosaccharides at the start of the reaction so that the product mixture contained a higher proportion of maltose. These results indicate that AmyFlA may be potential application value in the production of high-maltose syrup.

Cyanobacteria-Mediated Light-Driven Biotransformation: The Current Status and Perspectives

Most chemicals are manufactured by traditional chemical processes but at the expense of toxic catalyst use, high energy consumption, and waste generation. Biotransformation is a green, sustainable, and cost-effective process. As cyanobacteria can use light as the energy source to power the synthesis of NADPH and ATP, using cyanobacteria as the chassis organisms to design and develop light-driven biotransformation platforms for chemical synthesis has been gaining attention, since it can provide a theoretical and practical basis for the sustainable and green production of chemicals. Meanwhile, metabolic engineering and genome editing techniques have tremendous prospects for further engineering and optimizing chassis cells to achieve efficient light-driven systems for synthesizing various chemicals. Here, we display the potential of cyanobacteria as a promising light-driven biotransformation platform for the efficient synthesis of green chemicals and current achievements of light-driven biotransformation processes in wild-type or genetically modified cyanobacteria. Meanwhile, future perspectives of one-pot enzymatic cascade biotransformation from biobased materials in cyanobacteria have been proposed, which could provide additional research insights for green biotransformation and accelerate the advancement of biomanufacturing industries.

Self-Seeding Synthesis of Hierarchically Branched Rutile TiO2 for High-Efficiency Dye-Sensitized Solar Cells

This study presents a unique and straightforward room temperature-based wet-chemical technique for the self-seeding preparation of three-dimensional (3D) hierarchically branched rutile TiO₂, abbreviated HTs, employing titanate nanotubes as the precursor. In the course of the synthesis, spindle-like rutile TiO₂ and the intermediate anatase phase were first obtained through a dissolution/precipitation/recrystallization process, with the former serving as the substrates and the latter as the nucleation precursor to growing the branches, which finally gave birth to the production of 3D HTs nanostructures. When the specifically created hierarchical TiO₂ was used as the photoanode in dye-sensitized solar cells (DSCs), a significantly improved power conversion efficiency (PCE) of 8.32% was achieved, outperforming a typical TiO₂ (P25) nanoparticle-based reference cell (η = 5.97%) under the same film thickness. The effective combination of robust light scattering, substantial dye loading, and fast electron transport for the HTs nanostructures is responsible for the remarkable performance.

Novel Optical Fiber-Based Structures for Plasmonics Sensors

Optical fiber sensors based on surface plasma technology have many unique advantages in specific applications such as extreme environmental monitoring, physical parameter determination, and biomedical indicators testing. In recent decades, various kinds of fiber probes with special structures were developed according to special processing such as tapering, splicing, etching, fiber balls, grating etc. In this paper, the fabrication technology, characteristics, development status and application scenarios of different special optical fiber structures are briefly reviewed, including common processing equipment. Furthermore, many special novel optical fiber structures reported in recent years are summarized, which have been used in various kinds of plasmonic sensing work. Then, the fiber-plasmonic sensors for practical applications are also introduced and examined in detail. The main aim of this review is to provide guidance and inspiration for researchers to design and fabricate special optical fiber structures, thus facilitating their further research.

Multicore Fiber Bending Sensors with High Sensitivity Based on Asymmetric Excitation Scheme

Bending sensing was realized by constructing a tapered four-core optical fiber (TFCF) sensor. The four-core fiber (FCF) between the fan-in and fan-out couplers was tapered and the diameter became smaller, so that the distance between the four cores arranged in a square became gradually smaller to produce supermodes. The two ends of the TFCF were respectively connected to the fan-in and fan-out couplers so that the individual cores in the FCF could link to the separate single-mode fibers. A broadband light source (superluminescent diodes (SLD)) spanning 1250-1650 nm was injected into any one of the four cores, and the orientation was thus determined. In the tapering process, the remaining three cores gradually approached the excitation core in space to excite several supermodes based on the tri-core structure first, and then transited to the quadruple-core structure. The field distributions of the excited supermodes were asymmetric due to the corner-core excitation scheme, and the interference thus resulted in a higher measurement sensitivity. When the diameter of the TFCF was 7.5 μm and the tapered length was 2.21 mm, the sensitivity of the bending sensor could reach 16.12 nm/m-1.

Explanation and Exploration of the Isothermal Titration Curve for the NaCl + Na2SO4 + H2O System at 298.15 K and 102.2 kPa

Isothermal titration microcalorimetry (ITC) is a common and powerful tool in thermodynamics and related fields, and the connection between the solution behavior and raw titration curve is complex, important, and worth studying, so we try to discuss this problem using a complex solid-solid-liquid diagram. Although there are many experimental methods for studying ternary phase diagrams, ITC has been proven to be a simple, universal method at normal temperature and pressure. This method can be extended to investigate phase diagrams of multisalt aqueous solutions and related systems. Here, the phase equilibrium of one common ternary system (NaCl + Na₂SO₄ + H₂O) was determined using the ITC method with the aid of X-ray diffraction measurements. This isothermal and isobaric titration method can be used not only to determine the boundaries of different phase regions by analyzing changes in the slope of the observed heat vs solvent concentration plot but also to provide additional accurate data regarding the solid dissolution enthalpy and the dilution enthalpy. The dissolution enthalpy of 1 mol NaCl (Na₂SO₄) solid dissolving in water to just form a saturated solution is measured at 1.92 kJ/mol (-15.60 kJ/mol), and the dissolution enthalpy of the mixed solids can be evaluated with these data. The dilution enthalpy is strongly dependent on the solute concentration (0.08-0.23 kJ/mol at the range of concentration studied), and for the same range concentration of a solute, the dilution enthalpy of Na₂SO₄ is positive and larger than that of NaCl. Therefore, the connection between the observed heat and the microscopic behavior and the separation between the dissolution and dilution data may result in the possibility to gain a clearer understanding about the solution behaviors.

High Sensitivity Strain Sensors Using Four-Core Fibers through a Corner-Core Excitation

A weakly-coupled multicore fiber can generate supermodes when the multi-cores are closer to enter the evanescent power coupling region. The high sensitivity strain sensors using tapered four-core fibers (FCFs) were demonstrated. The fan-in and fan-out couplers were used to carry out light coupling between singlemode fibers and the individual core of the FCFs. A broadband lightsource from superlumminescent diodes (SLDs) was launched into one of the four cores arranged in a rectangular configuration. When the FCF was substantially tapered, the asymmetric supermodes were produced to generate interferences through this corner-core excitation scheme. During tapering, the supermodes were excited based on a tri-core structure initially and then transited to a rectangular quadruple-core structure gradually to reach the sensitivity of 185.18 pm/μԑ under a tapered diameter of 3 μm. The asymmetric evanescent wave distribution due to the corner-core excitation scheme is helpful to increase the optical path difference (OPD) between supermodes for improving the strain sensitivity.

MgGd4Si3O13:Ce3+, Mn2+: A Dual-Excitation Temperature Sensor

A novel apatite-based phosphor MgGd₄Si₃O₁₃[Mg₂Gd₈(SiO₄)₆O₂]:Ce³⁺, Mn²⁺ was designed and successfully synthesized by a solid-state reaction. Based on the different luminescence properties under 298 and 340 nm excitations, its potential application as a dual-excitation luminescent ratiometric thermometer was studied in detail. Under the excitations of 298 and 340 nm, the fluorescent intensity ratio of Ce³⁺ and Mn²⁺ is linearly correlated in the temperature range of 303-473 K. The sensitivity showed an opposite trend with the increase of temperature, and the maximum value was 0.95% K^-1. These results indicated that MgGd₄Si₃O₁₃: Ce³⁺, Mn²⁺ can be used as an ideal dual-excitation luminescent ratiometric thermometer.

Jasmonate and Melatonin Act Synergistically to Potentiate Cold Tolerance in Tomato Plants

Both jasmonic acid (JA) and melatonin (MT) have been demonstrated to play positive roles in cold tolerance, however, whether and how they crosstalk in the cold responses in plants remain elusive. Here, we report that JA and MT act synergistically in the cold tolerance in tomato plants (Solanum lycopersicum). It was found that JA and MT were both substantially accumulated in response to cold stress and foliar applications of methyl jasmonate (MeJA) and MT promoted cold tolerance as evidenced by increased Fv/Fm, decreased relative electrolyte leakage (EL) and declined H₂O₂ accumulation in tomato plants. Inhibition of MT biosynthesis attenuated MeJA-induced cold tolerance, while inhibition of JA biosynthesis reduced MT accumulation in tomato plants under cold conditions. Furthermore, qRT-PCR analysis showed that the expressions of two MT biosynthetic genes, SlSNAT and SlAMST, were strongly induced by MeJA, whereas suppression of SlMYC2, a master JA signaling regulator, abated the expressions of SlSNAT and SlAMST under cold stress. Additionally, suppression of SlMYC2 reduced MT accumulation, decreased Fv/Fm and increased EL in cold-stressed tomato plants. Interestingly, exogenous MT promoted JA accumulation, while inhibition of MT biosynthesis significantly reduced JA accumulation in tomato plants under the cold condition. Taken together, these results suggest that JA and MT act cooperatively in cold tolerance and form a positive feedback loop, amplifying the cold responses of tomato plants. Our findings might be translated into the development of cold-resistant tomato cultivars by genetically manipulating JA and MT pathways.

A Bio-Based Hydrogel Derived from Moldy Steamed Bread as Urea-Formaldehyde Loading for Slow-Release and Water-Retention Fertilizers

In this work, a novel slow-release and water-retention nitrogen (N) fertilizer (SRWRNF) was prepared using moldy steamed bread-based starch-g-poly(acrylic acid-co-acrylic amide) (SBS-g-P(AA/AM)) as the skeleton and urea-formaldehyde oligomers (UF) incorporated as the slow-release N source by semi-interpenetrating methods. Various analysis technologies including scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry were used to characterize the structure and properties of SRWRNFs. Swelling measurements indicated that the maximum water absorbency of SBS-g-P(AA/AM)-UF samples was 104.2 g/g in distilled water. The water-retention study showed that the SBS-g-P(AA/AM)-UF improved the maximum soil water content by 15.3-17.6% while improving soil water-retention capacity. N release experiments confirmed that SBS-g-P(AA/AM)-UF enabling offered a gradual N supply in soil. In comparison to conventional urea and UF fertilizers, the maize yield of SBS-g-P(AA/AM)-UF was increased by 20.3 and 9.7%, respectively. This study implies that the SRWRNFs provide a promising feasibility for large-scale applications in agriculture.

Nanotechnology based therapeutic application in cancer diagnosis and therapy

Due to the lack of early diagnosis, cancer remains as one of the leading cause of human mortality. Inability to translate research into clinical trials and also inability of chemotherapeutics delivery to targeted tumor sites are major drawbacks in cancer therapeutics. With the emergence of nanomedicine, several nanoprobes (conjugated with targeting ligands and chemotherapeutic drugs) are developed. It can interact with biological system and thus sense and monitor the biological events with high efficiency and accuracy along with therapy application. Nanoparticles like gold and iron oxide are frequently used in the computed tomography and magnetic resonance imaging applications, respectively. Moreover, enzymatic activity of gold and iron oxide nanoparticles enables the visible colorimetric diagnostic of cancer cells, whereas, fluorescence property of quantum dots and upconversion nanoparticles helps in in vivo imaging application. Other than this, drug conjugation with nanoparticles also reduces the systemic toxic effect of chemotherapeutic drugs. Due to their several unique intrinsic properties, nanoparticles itself can also be employed as therapeutics in cancer treatment by photothermal therapy (PTT) and photodynamic therapy (PDT). Thus, the main focus of this review is to emphasize on current progress in diagnostic and therapeutic application of nanoprobes in cancer.