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Journal of Biomaterials Science.... Jul 2024The interest in wound dressings increased ten years ago. Wound care practitioners can now use interactive/bioactive dressings and tissue-engineered skin substitutes....
The interest in wound dressings increased ten years ago. Wound care practitioners can now use interactive/bioactive dressings and tissue-engineered skin substitutes. Several bandages can heal burns, but none can treat all chronic wounds. This study formulates a composite material from 70% polyvinyl alcohol (PVA) and 30% polyethylene glycol (PEG) with 0.2, 0.4, and 0.6 wt% magnesium oxide nanoparticles. This study aims to create a biodegradable wound dressing. A Fourier Transform Infrared (FTIR) study shows that PVA, PEG, and MgO create hydrogen bonding interactions. Hydrophilic characteristics are shown by the polymeric blend's 56.289° contact angle. MgO also lowers the contact angle, making the film more hydrophilic. Hydrophilicity improves film biocompatibility, live cell adhesion, wound healing, and wound dressing degradability. Differential Scanning Calorimeter (DSC) findings suggest the PVA/PEG combination melted at 53.16 °C. However, adding different weight fractions of MgO nanoparticles increased the nanocomposite's melting temperature (T). These nanoparticles improve the film's thermal stability, increasing Tm. In addition, MgO nanoparticles in the polymer blend increased tensile strength and elastic modulus. This is due to the blend's strong adherence to the reinforcing phase and MgO nanoparticles' ceramic material which has a great mechanical strength. The combination of 70% PVA + 30% PEG exhibited good antibacterial spatially at 0.2% MgO, according to antibacterial test results.
PubMed: 38949409
DOI: 10.1080/09205063.2024.2364526 -
Organic Letters Jul 2024Thiourea -oxides are labile compounds that suffer from a quick overoxidation when directly prepared from thioureas. Therefore, we have developed an alternative route on...
Thiourea -oxides are labile compounds that suffer from a quick overoxidation when directly prepared from thioureas. Therefore, we have developed an alternative route on the basis of the SO transfer from a thiirane -oxide onto sterically encumbered -heterocyclic carbenes, including imidazole- and imidazoline-ylidenes, and a cyclic alkyl amino carbene. Reaction conditions and DFT computations suggest a concerted SO transfer mechanism. Thiourea -oxides are nucleophiles adding to dimethyl acetylenedicarboxylate under fission of the S-O bond.
PubMed: 38949383
DOI: 10.1021/acs.orglett.4c02253 -
Dalton Transactions (Cambridge, England... Jul 2024A novel lysosome-targeted photosensitizer/photoredox catalyst based on cyclometalated Ir(III) complex IrL has been designed and synthesized, which exhibited excellent...
A novel lysosome-targeted photosensitizer/photoredox catalyst based on cyclometalated Ir(III) complex IrL has been designed and synthesized, which exhibited excellent phosphorescence properties and the ability to generate single oxygen (O) and photocatalytically oxidize 1,4-dihydronicotinamide adenine dinucleotide (NADH) under light irradiation. Most importantly, the aforementioned activities are significantly enhanced due to protonation under acidic conditions, which makes them highly attractive in light-activated tumor therapy, especially for acidic lysosomes and tumor microenvironments. The photocytotoxicity of IrL and the mechanism of cell death have been investigated. Additionally, the tumor-killing ability of IrL under light irradiation was evaluated using a 4T1 tumor-bearing mouse model. This work provides a strategy for the development of lysosome-targeted photosensitizers/photoredox catalysts to overcome hypoxic tumors.
PubMed: 38949269
DOI: 10.1039/d4dt01345j -
Nanotechnology Jul 2024The emergence of piezoelectric nanogenerators presents a promising alternative to supply energy demands within the realms of portable and miniaturized devices. In this...
The emergence of piezoelectric nanogenerators presents a promising alternative to supply energy demands within the realms of portable and miniaturized devices. In this article, the role of 2D transition metal dichalcogenide (TMD) tungsten sulfide (WS2) and conductive rGO sheets as filler materials inside the polyvinylidene fluoride (PVDF) matrix on piezoelectric performances has been investigated extensively. The strong electrostatic interaction between C-F and C-H monomer bonds of PVDF interacted with the large surface area of the WS2 nanosheets, increasing the electroactive polar phases and resulting in enhanced ferroelectricity in the PVDF/WS2 nanocomposite. Further, the inclusion of rGO sheets in the PVDF/WS2 composite allows mobile charge carriers to move freely through the conductive network provided by the rGO basal planes, which improves the internal polarization of the PVDF/WS2/rGO nanocomposites and increases the electrical performance of the piezoelectric nanogenerators (PENGs). The PVDF/WS2/0.3rGO nanocomposite-based PENG exhibits maximum piezoresponses with ~8.1 times enhancements in the output power density than the bare PVDF-based PENG. The mechanism behind the enhanced piezoresponses in the PVDF/WS2/rGO nanocomposites has been discussed. .
PubMed: 38949268
DOI: 10.1088/1361-6528/ad5d69 -
ACS Applied Materials & Interfaces Jul 2024Trauma is the leading cause of death for adults under the age of 44. Internal bleeding remains a significant challenge in medical emergencies, necessitating the...
Trauma is the leading cause of death for adults under the age of 44. Internal bleeding remains a significant challenge in medical emergencies, necessitating the development of effective hemostatic materials that could be administered by paramedics before a patient is in the hospital and treated by surgeons. In this study, we introduce a graphene oxide (GO)-based PEGylated synthetic hemostatic nanomaterial with an average size of 211 ± 83 nm designed to target internal bleeding by mimicking the role of fibrinogen. Functionalization of GO--PEG with peptides derived from the α-chain of fibrinogen, such as GRGDS, or the γ-chain of fibrinogen, such as HHLGGAKQAGDV:H12, was achieved with peptide loadings of 72 ± 6 and 68 ± 15 μM, respectively. studies with platelet-rich plasma (PRP) under confinement demonstrated aggregation enhancement of 39 and 24% for GO--PEG-GRGDS and GO--PEG-H12, respectively, compared to buffer, while adenosine diphosphate (ADP) alone induced a 5% aggregation. Compared to the same materials in the absence of ADP, GO--PEG-GRGDS achieved a 47% aggregation enhancement, while GO--PEG-H12 a 25% enhancement. This is particularly important for injectable hemostats and highlights the fact that our nanographene-based materials can only act as hemostats in the presence of agonists, reducing the possibility of unwanted clotting during circulation. Further studies on collagen-coated wells under dynamic flow revealed statistically significant augmentation of PRP fluorescence signal using GRGDS- or H12-coated GO--PEG compared to controls. Hemolysis studies showed <1% lysis of red blood cells (RBCs) at the highest PEGylated nanographene concentration. Finally, whole human blood coagulation studies reveal faster and more pronounced clotting using our nanohemostats PBS control from 3 min and below (blood is clotted with 10% CaCl within 4-5 min), with the biggest differences to be shown at 2 and 1 min. At 1 min, the clot weight was found to be ∼45% of that between 4 and 5 min, while no clot was formed in PBS-treated blood. Reduction of CaCl to 5 and 3%, or utilization of prostaglandin E1, an anticoagulant, still leads to clots but of smaller weight. The findings highlight the potential of our fibrinogen-mimic PEGylated nanographene as a promising non-hemolytic injectable scaffold for targeting internal bleeding, offering insights into its platelet aggregation capabilities under confinement and under dynamic flow as well as its pronounced coagulation abilities.
PubMed: 38949260
DOI: 10.1021/acsami.4c09828 -
Chemistry & Biodiversity Jul 2024Research interest in examining Elaeagnus angustifolia's potential as a source of anti-inflammatory and antioxidant agents has grown as a result of the plant's...
Research interest in examining Elaeagnus angustifolia's potential as a source of anti-inflammatory and antioxidant agents has grown as a result of the plant's endorsement as a rich source of bioactive chemicals with promising anti-inflammatory and antioxidant activity. In this study, zinc oxide (Fe0.25-ZnO) bimetallic nanoparticles (E.ang-Fe0.25-ZnO NPs) were synthesized using an aqueous extract of Elaeagnus angustifolia. Synthesized Fe0.25-ZnO nanoparticles were characterized by FTIR and XRD. The anti-inflammatory and antioxidant activities were investigated in LPS-stimulated RAW 264.7 macrophages using RT-PCR and ELISA techniques for antioxidant- and inflammation-related genes. The concentration of 39.6µg/ml of E.ang-Fe0.25-ZnO NPs demonstrated a significant anti-inflammatory activity by suppressing the mRNA levels of TNF-α and IL-6 by 88.3%±1.9 and 93.6%±0.1, respectively, compared to LPS-stimulated cells. This was confirmed by the significant reduction of TNF-α and IL-6 secretion levels from 95.2 and 495.6 pg/ml in LPS-stimulated cells to 5.6 and 26.5 pg/ml in E.ang-Fe0.25-ZnO treated group. In addition, E.ang-Fe0.25-ZnO NPs nanoparticles treatment significantly enhanced the expression of antioxidant-related genes, SOD and CAT. Together, our results proved that phyto-mediated Fe0.25-ZnO nanoparticles using Elaeagnus angustifolia have great potential in biomedical applications such as anti-inflammatory and antioxidant.
PubMed: 38949232
DOI: 10.1002/cbdv.202401060 -
ChemPlusChem Jul 2024Lithium-ion batteries (LIBs) are widely used in electric vehicles, portable electronic devices, clean energy storage, and other fields due to their long service life,...
Lithium-ion batteries (LIBs) are widely used in electric vehicles, portable electronic devices, clean energy storage, and other fields due to their long service life, high energy density, and low self-discharge rate, which also puts forward higher requirements for the performance of lithium-ion batteries. As an anode for lithium-ion batteries, SiO materials have garnered significant attention from researchers due to its high specific capacity (2400 mAh·g-1), abundance of raw materials, and simple preparation. However, its large volume change (~ 200%) and poor electrical conductivity hinder its large-scale commercial application. Researchers employ various methods to reduce the volume change of SiO during lithium intercalation and improve its structural stability during cycling. This work mainly reviews the chemical structure and lithium storage mechanism of SiO, as well as the latest research progress on the preparation methods of SiO/C anode materials, focusing on summarizing the following preparation strategies: chemical vapor deposition, mechanical ball milling, spray drying, and in-situ reduction/oxidation methods. The obtained SiO-based anode materials' structural characteristics and electrochemical properties are compared and summarized. Finally, this review discusses the advantages and disadvantages of the current preparation methods, the future research directions, and the development prospects of SiO-based anode materials.
PubMed: 38949230
DOI: 10.1002/cplu.202400240 -
Angewandte Chemie (International Ed. in... Jul 2024This paper describes a concise, asymmetric and stereodivergent total synthesis of tacaman alkaloids. A key step in this synthesis is the biocatalytic Baeyer-Villiger...
This paper describes a concise, asymmetric and stereodivergent total synthesis of tacaman alkaloids. A key step in this synthesis is the biocatalytic Baeyer-Villiger oxidation of cyclohexanone, which was developed to produce seven-membered lactones and establish the required stereochemistry at the C14 position (92% yield, 99% ee, 500 mg scale). Cis- and trans-tetracyclic indoloquinolizidine scaffolds were rapidly synthesized through an acid-triggered, tunable acyl-Pictet-Spengler type cyclization cascade, serving as the pivotal reaction for building the alkaloid skeleton. Computational results revealed that hydrogen bonding was crucial in stabilizing intermediates and inducing different addition reactions during the acyl-Pictet-Spengler cyclization cascade. By strategically using these two reactions and the late-stage diversification of the functionalized indoloquinolizidine core, the asymmetric total syntheses of eight tacaman alkaloids were achieved. This study may potentially advance research related to the medicinal chemistry of tacaman alkaloids.
PubMed: 38949229
DOI: 10.1002/anie.202407149 -
International Maritime Health 2024Saturation diving is a standard method of intervention for commercial diving during offshore operations. Current saturation procedures achieve a high level of safety...
BACKGROUND
Saturation diving is a standard method of intervention for commercial diving during offshore operations. Current saturation procedures achieve a high level of safety with regards to decompression sickness but still put the divers under multiple stressors: 1) Environmental stress (long confinement, heat/cold, dense gases, high oxygen levels), 2) Work stress (muscular fatigue, psychological pressure, breathing equipment, etc.), 3) venous gas emboli associated with decompression, 4) Inflammation related to oxidative stress and microparticles. We present the results of a saturation divers monitoring campaign performed in the North Sea Danish sector, on the Tyra field, during 2022. The study was supported by TotalEnergies, the field operator, and performed by Boskalis Subsea Services, the diving contractor, onboard the diving support vessel Boka Atlantis. The objective was twofold: document the level of diving stress during saturation operations in the Danish sector, and compare the performances of two saturation procedures, the Boskalis and the NORSOK procedures.
MATERIALS AND METHODS
Fourteen divers volunteered for the study. The monitoring package include weight and temperature measurements, psychomotor tests (objective evaluation) and questionnaires (subjective evaluation), Doppler bubble detection and bioimpedance. The results were presented in a radar diagram that provides a general view of the situation.
RESULTS
The data were analysed along 3 dimensions: work and environmental, desaturation bubbles, oxidative stress and inflammation. The results showed little or no variations from the reference values. No bubbles were detected after excursion dives and the final decompression, except for two divers with a grade 1 after arriving at surface. No statistical difference could be found between the Boskalis and the NORSOK saturation procedures.
CONCLUSIONS
At a depth of 40-50 msw corresponding to the Danish sector, the two saturation procedures monitored induce no or little stress to the divers. The divers know how to manage their diet, equilibrate their hydration and pace their effort. Data available on divers' post saturation period show a recovery over the 24-48 hours following the end of the decompression. Further research should focus on diving deeper than 100 msw where a greater stress can be anticipated.
Topics: Humans; Diving; Decompression Sickness; North Sea; Adult; Male; Oxygen Saturation; Middle Aged; Stress, Physiological; Denmark; Monitoring, Physiologic
PubMed: 38949219
DOI: 10.5603/imh.99606 -
International Journal of... Jul 2024Green synthesis of nanomaterials is advancing due to their ease of synthesis, cheapness, nontoxicity, and renewability. An environmentally friendly biogenic method has...
Green synthesis of nanomaterials is advancing due to their ease of synthesis, cheapness, nontoxicity, and renewability. An environmentally friendly biogenic method has been developed for the green synthesis of nickel oxide nanoparticles (NiO NPs) using phytochemical-rich bioextract. They are rich in bioextract phenolics, flavonoids, and berberine. These phytochemicals successfully reduce and stabilize NiNO into NiO NPs. In this study, NiO NPs were synthesized by the green synthesis method from Lupinus Albus. Characterization of NiO NPs was carried out by TEM, XRD, SEM, UV, XRF, BET, and EDX analyses. According to XRD analysis, TEM results also support this, where the NiO NPs particle size diameter is 5 nm. It was determined by the Tauc equation that the band energy gap of NiO NPs is 1.69 eV. It was determined that the BET surface area of NiO NPs was 49.6 m/g. NiO nanoparticles synthesized from Lupinus Albus extract by the green synthesis method were used as catalysts in the photocatalytic reduction of methylene blue with NaBH. In the photocatalytic reduction of methylene blue with NaBH, it was determined that there was no color change in 48 h without a catalyst, and in the presence of NiO nanoparticle catalyst, methylene blue was reduced by 97% in 8 min. The kinetics of the photocatalytic reduction of methylene blue with NaBH is a pseudo-first-order kinetic model and the kinetic rate constant is determined as 0.66 min, indicating that the catalytic effect of NiO NPs is very high at this value. NiO NPs were used five times in the photocatalytic reduction of methylene blue with NaBH and it was determined that the reduction of methylene blue was over 90% in each use.
PubMed: 38949210
DOI: 10.1080/15226514.2024.2371914