Synthesis of Os@ZIF-8 nanocomposites with enhanced peroxidase-like activity for detection of Hg2.

Metal organic framework (MOF)-derived nanostructures display remarkable characteristics and have broad application potential. Os@ZIF-8 nanocomposites were prepared by a depositional method. The Os nanoparticles distributed on the surface of ZIF-8. The nanocomposites displayed enhanced peroxidase-like activity with smaller Km for both 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2 compared to Os NPs due to the confinement effect and large surface area that ZIF-8 provided. From the average reaction rate constants obtained from three different temperatures, the activation energy values were determined. The kinetic data indicated that the Os@ZIF-8 NCs are catalytically more active than Os NPs. In addition, quantitative measurement of Hg2+ was performed based on the formation of Os-Hg alloy. Os@ZIF-8 NCs had a wide detection range between 0 µM and 71.43 µM for Hg2+ with a limit of detection (LOD) of 2.29 µM. Using a MOF with a large surface area to load Os nanoparticles to achieve enhanced nanozyme activity is the novelty of this work.

Molecular Engineering Modulating the Singlet-Triplet Energy Splitting of Indolocarbazole-Based TADF Emitters Exhibiting AIE Properties for Nondoped Blue OLEDs with EQE of Nearly 20.

The development of efficient blue thermally activated delayed fluorescence (TADF) emitters with an aggregation-induced emission (AIE) nature, for the construction of organic light-emitting diodes (OLEDs), is still insufficient. This can be attributed to the challenges encountered in molecular design, including the inherent trade-off between radiative decay and reverse intersystem crossing (RISC), as well as small singlet-triplet energy splitting (ΔEST) and the requirement for high photoluminescence quantum yields (ΦPL). Herein, we present the design of three highly efficient blue TADF molecules with AIE characteristics by combining π-extended donors with different acceptors to modulate the differences in the electron-donating and electron-withdrawing abilities. This approach not only ensures high emission efficiency by suppressing close π-π stacking, weakening nonradiative relaxation, and enhancing radiative transition but also maintains the equilibrium ratio between the triplet and singlet excitons by facilitating the process of RISC. These emitters exhibit AIE and TADF properties, featuring quick radiative rates and low nonradiative rates. The ΦPL of these emitters reached an impressive 88%. Based on their excellent comprehensive performance, nondoped PICzPMO and PICzPMO OLEDs achieved excellent electroluminescence performance, exhibiting maximum external quantum efficiency (EQEmax) of up to 19.5%, while the doped device achieved a higher EQEmax of 20.8%. This work demonstrated that by fusing π-extended large rigid donors with different acceptors, it is possible to regulate the difference in electron-donating and electron-withdrawing abilities, resulting in a small ΔEST, high ΦPL, and fast RISC process, which is a highly feasible strategy for designing efficient TADF molecules.

Effect of intramedullary nail fixation and internal plate fixation in distal tibia fracture surgery on post-operative wound infection in patients: A meta-analysis.

Distal tibial fracture is the most commonly seen type of fracture of the lower extremities. Both intramedullary nail fixation (INF) and plate fixation (PF) have been used to treat distal tibial fractures, but the best way to treat them is still in dispute. The purpose of this meta-analysis is to compare INF versus PF fixation with respect to the incidence of injury. For studies that have been published between inception and June 2023, a systematic review has been carried out on PubMed, Embase, Cochrane Library and Web of Scientific databases. All of the trials that looked at INF and PF-related complications were enrolled. Data from the 13 primary results were analysed with RevMan 5.3. The meta-analyses comprised 13 randomized controlled trials (RCTs). INF indicates that there is a tendency for patients with distal tibia fractures to reduce the risk of operative site infection (odds ratio [OR], 2.09; 95% confidence interval [CI], 1.40, 3.13; p = 0.0003) after surgery compared with PF. INF resulted in a reduction in total wound complications (OR, 14.20; 95% CI, 1.81, 111.57; p = 0.01) but shortened operation time (mean difference, 13.03; 95% CI, 2.08, 23.99; p = 0.02). In view of these findings, INF seems to be a preferred method of surgery for the treatment of distal tibial fractures with respect to the reduction of post-operative wound complications.

Effect of dexmedetomidine combined with local infiltration analgesia on postoperative wound complications in patients with total knee arthroplasty: A meta-analysis.

Dexmedetomidine has been demonstrated to be effective in the management of pain in total knee replacement (TKA). Nevertheless, a combination of a local anaesthetic and a dose of dexmedetomidine might be a better choice for post-operative pain management of TKA. The aim of this research is to determine if the combination of a local anaesthetic with dexmedetomidine during a knee replacement operation can decrease the post-operation pain. Furthermore, the effectiveness and security of dexmedetomidine combined with topical anaesthetic were evaluated for the management of post-operative TKA. Based on the research results, the author made a research on the basis of four big databases. The Cochrane Handbook on Intervention Systems Evaluation has also evaluated the quality of the literature. Seven randomized controlled trials have been established from this. It was found that the combination of local anaesthesia and dexmedetomidine had a greater effect on postoperative pain in 4 h (mean difference [MD], -0.9; 95% CI, -1.71, -0.09; p = 0.03), 8 h (MD, -0.52; 95% CI, -0.66, -0.38; p < 0.0001), 12 h (MD, -0.72; 95% CI, -1.04, -0.40; p < 0.0001), 24 h (MD, -0.49; 95% CI, -0.83, -0.14; p = 0.006), 48 h (MD, -0.51; 95% CI, -0.92, -0.11; p = 0.01). Nevertheless, because of the limited number of randomized controlled trials covered by this meta-analysis, caution should be exercised with regard to data treatment. More high quality research will be required to confirm the results.

A colorimetric sensor based on Glutathione-AgNPs as peroxidase mimetics for the sensitive detection of Thiamine (Vitamin B1).

A label-free sensing strategy based on the enzyme-mimicking property of Glutathione-Ag nanoparticles (GSH-AgNPs) was demonstrated for colorimetric detection of vitamin B1 (VB1). Firstly, obvious blue color accompanied with an absorption peak at 652 nm was observed due to the high peroxidase-like activity of GSH-AgNPs towards 3,3',5,5'-tetramethylbenzidine (TMB). Then, in the presence of VB1, the mimetic activity of GSH-AgNPs could be strongly restrained, evidenced as a promiment colorimetric change to colorless, which can be used to achieve the visualization detection VB1. Linear relationship between absorbance response and VB1 concentration from 0 to 0.2 µM were obtained. The detection limit was calculated as low as 40 nM. The inhibition reasons were thoroughly discussed. Considering the advantages of rapid response, easy procedure and high selectivity, the proposed method possesses potential application in environment and biological analysis for VB1 detection.

Effective Design Strategy for Aggregation-Induced Emission and Thermally Activated Delayed Fluorescence Emitters Achieving 18% External Quantum Efficiency Pure-Blue OLEDs with Extremely Low Roll-Off.

High-color purity organic emitters with a simultaneous combination of aggregation-induced emission (AIE) and thermally activated delayed fluorescence (TADF) characteristics are in great demand due to their excellent comprehensive performances toward efficient organic light-emitting diodes (OLEDs). In this work, two D-π-A-structure emitters, ICz-DPS and ICz-BP, exhibiting AIE and TADF properties were developed, and both the emitters have narrow singlet (S1)-triplet (T1) splitting (ΔEST) and excellent photoluminescence (PL) quantum yields (ΦPL), derived from the distorted configurations and weak intra/intermolecular interactions, suppressing exciton annihilation and concentration quenching. Their doped OLEDs based on ICz-BP provide an excellent electroluminescence external quantum efficiency (ηext) and current efficiency (ηC) of 17.7% and 44.8 cd A-1, respectively, with an ηext roll-off of 2.9%. Their nondoped OLEDs based on ICz-DPS afford high efficiencies of 11.7% and 30.1 cd A-1, with pure-blue emission with Commission Internationale de l'Éclairage (CIE) coordinates of (0.15, 0.08) and a low roll-off of 6.0%. This work also shows a strategy for designing AIE-TADF molecules by rational use of steric hindrance and weak inter/intramolecular interactions to realize high ΦPL values, fast reverse intersystem crossing process, and reduced nonradiative transition process properties, which may open the way toward highly efficient and small-efficiency roll-off devices.

Computed Tomography Image Texture under Feature Extraction Algorithm in the Diagnosis of Effect of Specific Nursing Intervention on Mycoplasma Pneumonia in Children.

To evaluate the effect of specific nursing intervention in children with mycoplasma pneumonia (MP), a feature extraction algorithm based on gray level co-occurrence matrix (GLCM) was proposed and combined with computed tomography (CT) image texture features. Then, 98 children with MP were rolled into the observation group with 49 cases (specific nursing) and the control group with 49 cases (routine nursing). CT images based on feature extraction algorithm of optimized GLCM were used to examine the children before and after nursing intervention, and the recovery of the two groups of children was discussed. The results showed that the proportion of lung texture increase, rope shadow, ground glass shadow, atelectasis, and pleural effusion in the observation group (24.11%, 3.86%, 8.53%, 15.03%, and 3.74%) was significantly lower than that in the control group (28.53%, 10.23%, 13.34%, 21.15%, and 8.13%) after nursing (P < 0.05). There were no significant differences in the proportion of small patchy shadows, large patchy consolidation shadows, and bronchiectasis between the observation group and the control group (P > 0.05). In the course of nursing intervention, in the observation group, the disappearance time of cough, normal temperature, disappearance time of lung rales, and absorption time of lung shadow (2.15 ± 0.86 days, 4.81 ± 1.14 days, 3.64 ± 0.55 days, and 5.96 ± 0.62 days) were significantly shorter than those in the control group (2.87 ± 0.95 days, 3.95 ± 1.06 days, 4.51 ± 1.02 days, and 8.14 ± 1.35 days) (P < 0.05). After nursing intervention, the proportion of satisfaction and total satisfaction in the experimental group (67.08% and 28.66%) was significantly higher than that in the control group (40.21% and 47.39%), while the proportion of dissatisfaction (4.26%) was significantly lower than that in the control group (12.4%) (P < 0.05). To sum up, specific nursing intervention was more beneficial to improve the progress of characterization recovery and the overall recovery effect of children with MP relative to conventional nursing. CT image based on feature extraction algorithm of optimized GLCM was of good adoption value in the diagnosis and treatment of MP in children.

Cytidine-gold nanoclusters as peroxidase mimetic for colorimetric detection of glutathione (GSH), glutathione disulfide (GSSG) and glutathione reductase (GR).

Abnormal levels of glutathione (GSH) and glutathione oxidized (GSSG) usually relates to some diseases, thus quantifying the amount of GSH or GSSG is of great significance. A label-free sensing assay based on the enzyme-mimicking property of Cytidine-Au nanoclusters (Cy-AuNCs) was demonstrated for colorimetric detection of GSH, GSSG and glutathione reductase (GR). Firstly, obvious blue color accompanied with an absorption peak at 652 nm was observed due to the high peroxidase-like activity of Cy-AuNCs toward 3,3',5,5'-tetramethylbenzidine (TMB). Then, in the presence of target, the mimetic activity of Cy-AuNCs could be strongly inhibited and used to achieve the visualization detection. The inhibition effect arose from the surface interaction between GSH and Cy-AuNCs. Linear relationships between absorbance response and concentration were obtained between 0 and 0.4 mM for GSH, 0-2.5 mM for GSSG and 0-0.2 U/mL for GR. The limit of detection (LOD) was calculated as low as 0.01 mM, 0.03 mM and 0.003 U/mL for GSH, GSSG and GR, respectively. Furthermore, the proposed method displayed rapid response, easy procedure and high selectivity.

Digital Economy and Health: Does Green Technology Matter in BRICS Economies?

The present study attempts to examine the impact of digitization and green technology on the health outcomes of BRICS countries over the period of 1993-2019. Internet users measure digitalization, and health outcome is determined by life expectancy. The study employed the ARDL estimation approach for empirical investigation of country-specific analysis. GDP per capita and current health expenditures have been incorporated as control variables. The study findings reveal that digitalization results in increasing life expectancy in the long-run in BRICS except for Brazil. While green technology tends to enhance life expectancy in the long-run in Russia and China, it produces an insignificant impact on health outcomes in the short-run. While GDP and health expenditures also improve life expectancy in mostly BRICS economies in the long-run and short-run. Our study provides some policy implications for BRICS nations.

Pre-treatment of sugarcane bagasse with aqueous ammonia-glycerol mixtures to enhance enzymatic saccharification and recovery of ammonia.

In this work, an efficient aqueous ammonia with glycerol (AAWG) method to improve the digestibility of sugarcane bagasse (SCB) was developed. Response surface methodology was utilized to optimize the AAWG parameters to achieve the maximum total fermentable sugar concentration (TFSC) and total fermentable sugar yield (TFSY). Under optimal AAWG conditions, 13.59 g/L TFSC (9.25% ammonia, 1.86 h, 180 °C) and 0.4449 g/g TFSY (9.51% ammonia, 1.78 h, 180 °C) were achieved, with delignification of 77.81% and 70.91%, respectively. Compared to pretreatment with glycerol or aqueous ammonia, the AAWG method significantly enhanced the enzymatic efficiency of SCB. The ammonia was recovered from the pretreatment liquid by distillation, and about one-third of the ammonia was retained. The overall results indicate that AAWG is effectively used as a pretreatment method for recovering ammonia, which would largely contribute to the economic benefits of biomass biorefinery.

Cu@Au(Ag)/Pt nanocomposite as peroxidase mimic and application of Cu@Au/Pt in colorimetric detection of glucose and l-cysteine.

Nanomaterial-based artificial peroxidase has attracted extensive interests due to their distinct advantages over natural counterpart. Cu@Au/Pt and Cu@Ag/Pt nanocomposite with rambutan-like structure were prepared and discovered to function like peroxidase, which was illustrated by catalyzing the oxidation reaction of 3,3',5,5'-tetramethylbenzidine (TMB) accompanied with a blue color change. Steady-state investigation indicates that the catalytic kinetics of Cu@Au/Pt and Cu@Ag/Pt all followed typical Michaelis-Menten behaviors and Cu@Au/Pt showed a strong affinity for H2O2, while Cu@Ag/Pt showed strong affinity for TMB. The color change and absorbance intensity strongly depend on the concentration of H2O2, thus the direct determination of H2O2 and indirect detection of glucose were demonstrated using Cu@Au/Pt with a detection limit of 1.5 µM and 6 µM, respectively. What is more important, the method was applied for detection of glucose in 50% fetal bovine serum with a detection limit of 80 µM, which is much lower than the lowest glucose content in blood for diabetes (7 mM). Moreover, the Cu@Au/Pt nanocomposite were also successfully applied for sensing l-cysteine because of the inhibition effect. Considering the good peroxidase-like activity and novel structure, Cu@Au(Ag)/Pt is expected to have a wide range of applications in bioassays and biocatalysis.

Synthesis, Characterization, and Microwave Absorption Properties of Reduced Graphene Oxide/Strontium Ferrite/Polyaniline Nanocomposites.

Strontium ferrite nanoparticles were prepared by a coprecipitation method, and reduced graphene oxide/strontium ferrite/polyaniline (R-GO/SF/PANI) ternary nanocomposites were prepared by in situ polymerization method. The morphology, structure, and magnetic properties of the ternary nanocomposites were investigated by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), TEM, Raman, and VSM. The microwave-absorbing properties of the composites were measured by a vector network analyzer. The XRD patterns show the single phase of strontium hexaferrite without other intermediate phases. TEM photographs reveal that strontium ferrite nanoparticles are uniformly dispersed on the surfaces of R-GO sheets. The R-GO/SF/PANI nanocomposite exhibited the best absorption property with the optimum matching thickness of 1.5 mm in the frequency of 2-18 GHz. The value of the maximum RL was -45.00 dB at 16.08 GHz with the 5.48-GHz bandwidth. The excellent absorption properties of R-GO/SF/PANI nanocomposites indicated their great potential as microwave-absorbing materials.

Highly sensitive two-photon sensing of thrombin in serum using aptamers and silver nanoparticles.

Thrombin plays an important role in pathological conditions. It is important, however challenging, to detect thrombin in complex biological media for clinical practice and diagnostic applications. Here we demonstrate a label-free, fast, highly sensitive and selective two-photon sensing scheme for detection of thrombin on the picomolar level. The assay is based on interactions between thrombin and a DNA aptamer, which induce aggregation of silver nanoparticles to display significantly enhanced two-photon photoluminescence. The limit of detection (LOD) of this two-photon sensing assay is as low as 3.1 pM in the buffer solution, more than 400 times lower than that of the extinction method (1.3 nM). The dynamic range of this method covers more than 4 orders of magnitude. Furthermore, this two-photon sensing assay can be applied to detection of thrombin in 100% fetal bovine serum with LOD of 1.8 nM. In addition to the unique advantages of two-photon sensing such as deep penetration and localized detection, this method could be potentially integrated with two-photon microscopy to offer additional advantages of 3D detection and mapping for potential in vivo applications.

Two-photon induced photoluminescence and singlet oxygen generation from aggregated gold nanoparticles.

Metal nanoparticles have potential applications as bioimaging and photosensitizing agents. Aggregation effects are generally believed to be adverse to their biomedical applications. Here we have studied the aggregation effects on two-photon induced photoluminescence and singlet oxygen generation of Au nanospheres and Au nanorods of two different aspect ratios. Aggregated Au nanospheres and short Au nanorods were found to display enhanced two-photon induced photoluminescence and singlet oxygen generation capabilities compared to the unaggregated ones. The two-photon photoluminescence of Au nanospheres and short Au nanorods were enhanced by up to 15.0- and 2.0-fold upon aggregation, and the corresponding two-photon induced singlet oxygen generation capabilities were enhanced by 8.3 and 1.8-fold, respectively. The two-photon induced photoluminescence and singlet oxygen generation of the aggregated long Au nanorods were found to be lower than the unaggregated ones. These results support that the change in their two-photon induced photoluminescence and singlet oxygen generation originate from aggregation modulated two-photon excitation efficiency. This finding is expected to foster more biomedical applications of metal nanoparticles as Au nanoparticles normally exist in an aggregated form in the biological environments. Considering their excellent biocompatibility, high inertness, ready conjugation, and easy preparation, Au nanoparticles are expected to find more applications in two-photon imaging and two-photon photodynamic therapy.

Excitation Nature of Two-Photon Photoluminescence of Gold Nanorods and Coupled Gold Nanoparticles Studied by Two-Pulse Emission Modulation Spectroscopy.

Gold nanorods (Au NRs) and coupled gold nanospheres (Au NSs) are known to display strong two-photon photoluminescence (TPPL). Here two-pulse emission modulation (TPEM) and pump-probe measurements were performed on Au NRs and coupled Au NSs to understand their excitation mechanisms. The TPEM cross contributions of Au NRs and coupled Au NSs showed much slower decay compared with a two-photon absorption organic dye. Their decay time constants (4.0 ps for Au NRs and 3.1 ps for coupled Au NSs) match well with the lifetimes of intermediate states measured from pump-probe experiments. These results support the fact that strong TPPL in Au NRs and coupled Au NSs arises from two sequential one-photon absorption steps involving real intermediate states instead of coherent two-photon absorption. These results give direct evidence that previously observed aggregation-enhanced TPPL arises from enhanced two-photon excitation efficiency, which was facilitated by two sequential plasmon-coupling-enhanced one-photon absorption steps via real intermediate states.

Two-photon ratiometric sensing of Hg2+ by using cysteine functionalized Ag nanoparticles.

We have demonstrated a novel two-photon sensing strategy to detect mercury ions with high selectivity and sensitivity. This sensing approach is based on the observation that addition of Hg(2+) into a cysteine functionalized Ag nanoparticle solution could significantly enhance their two-photon emission. An enhancement factor of up to 100 fold was obtained when mercury was added. A detection limit of as low as 65 nM could be achieved. The sensitivity and sensing range can be easily tuned. Compared to the conventional colorimetric or extinction spectrum based methods, this scheme offers improved sensitivity, quantitative detection of Hg(2+) with a larger dynamic range, and allows detection deep into biological environments such as cells and tissues where deep penetration is required. The sensitivity could be further improved by using two-photon microscopy with the additional advantages of 3D detection and mapping.