Transmission Electron Microscopy Research Articles

Self-modification of Defective TiO2 under Controlled H2/Ar Gas Environment and Dynamics of Photoinduced Oxygen Vacancies.

In recent years, defective TiO2 has caught considerable research attention because of its potential to overcome the limits of low visible light absorption and fast charge recombination present in pristine TiO2 photocatalysts. Among the different synthesis conditions for defective TiO2, ambient pressure hydrogenation with the addition of Ar as inert gas for safety purposes has been established as an easy to realize process. Whether the Ar gas might still influence the resulting photocatalytic properties and defective surface layer remains an open question. Here, we reveal that the gas flow ratio between H2 and Ar has a crucial impact on the defective structure as well as the photocatalyic activity of TiO2. In particular, transmission electron microscopy (TEM) in combination with electron energy loss spectroscopy (EELS) revealed a larger width of the defective surface layer when using a H2/Ar (50%-50%) gas mixture over pure H2. Here, a possible reason could be the increase in dynamic viscosity of the gas mixture when Ar is added. Additionally, photoinduced enhanced Raman spectroscopy (PIERS) is implemented as a complementary approach to investigate the dynamics of the defective structures under ambient conditions which cannot be effortlessly realized by vacuum techniques like TEM.

MSC Promotes the Secretion of Exosomal lncRNA KLF3-AS1 to Regulate Sphk1 Through YY1-Musashi-1 Axis and Improve Cerebral Ischemia-Reperfusion Injury.

Stroke remains the 3rd leading cause of long-term disability globally. Over the past decade, mesenchymal stem cell (MSC) transplantation has been proven as an effective therapy for ischemic stroke. However, the mechanism of MSC-derived exosomal lncRNAs during cerebral ischemia/reperfusion (I/R) remains ambiguous. The oxygen-glucose deprivation/reoxygenation (OGD/R) and middle cerebral artery occlusion (MCAO) rat model were generated. MSCs were isolated and characterized by flow cytometry and histochemical staining, and MSC exosomes were purified and characterized by transmission electron microscopy, flow cytometry and Western blot. Western blot, RT-qPCR and ELISA assay were employed to examine the expression or secretion of key molecules. CCK-8 and TUNEL assays were used to assess cell viability and apoptosis. RNA immunoprecipitation and RNA pull-down were used to investigate the direct association between krüppel-like factor 3 antisense RNA 1 (KLF3-AS1) and musashi-1(MSI1). Yin Yang 1 (YY1)-mediated transcriptional regulation was assessed by chromatin immunoprecipitation and luciferase assays. The histological changes and immunoreactivity of key molecules in brain tissues were examined by H&E and immunohistochemistry. MSCs were successfully isolated and exhibited directionally differential potentials. MSC exosomal KLF3-AS1 alleviated OGD/R-induced inflammation in SK-N-SH and SH-SY5Y cells via modulating Sphk1. Mechanistical studies showed that MSI1 positively regulated KLF3-AS1 expression through its direct binding to KLF3-AS1. YY1 was identified as a transcription activator of MSI1 in MSCs. Functionally, YY1/MSI1 axis regulated the release of MSC exosomal KLF3-AS1 to modulate sphingosine kinase 1 (Sphk1)/NF-κB pathway, thereby ameliorating OGD/R- or cerebral I/R-induced injury. MSCs promote the release of exosomal KLF3-AS1 to regulate Sphk1 through YY1/MSI axis and improve cerebral I/R injury.

Achieving a High Thermally Conductive One Micron AlN Deposition by High Power Impulse Magnetron Sputtering plus Kick.

High-power impulse magnetron sputtering (HiPIMS) plus kick is a physical vapor deposition method that employs bipolar microsecond-scale voltage pulsing to precisely control the ion energy during sputter deposition. HiPIMS plus kick for AlN deposition is difficult since nitride deposition is challenged by low surface diffusion and high susceptibility to ion damage. In this current study, a systematic examination of the process parameters of HiPIMS plus kick was conducted. Under optimized main negative pulsing conditions, this study documented that a 25 V positive kick biasing for AlN deposition is ideal for optimizing a high quality film, as shown by X-ray diffraction and transmission electron microscopy as well as optimal thermal conductivity while increasing high speed deposition (25 nm/min) and obtaining ultrasmooth surfaces (rms roughness = 0.5 nm). HiPIMS plus kick was employed to deposit a single-texture 1 μm AlN film with a 7.4° rocking curve, indicating well oriented grains, which correlated with high thermal conductivity (121 W/m·K). The data are consistent with the optimal kick voltage enabling enhanced surface diffusion due to ion-substrate collisions without damaging the AlN grains.

Nanoformulation of dasatinib cannot overcome therapy resistance of pancreatic cancer cells with low LYN kinase expression.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most difficult to treat tumors. The Src (sarcoma) inhibitor dasatinib (DASA) has shown promising efficacy in preclinical studies of PDAC. However, clinical confirmation could not be achieved. Overall, our aim was to deliver arguments for the possible reinitiating clinical testing of this compound in a biomarker-stratifying therapy trial for PDAC patients. We tested if the nanofunctionalization of DASA can increase the drug efficacy and whether certain Src members can function as clinical predictive biomarkers. Methods include manufacturing of poly(vinyl alcohol) stabilized gold nanoparticles and their drug loading, dynamic light scattering, transmission electron microscopy, thermogravimetric analysis, Zeta potential measurement, sterile human cell culture, cell growth quantification, accessing and evaluating transcriptome and clinical data from molecular tumor dataset TCGA, as well as various statistical analyses. We generated homo-dispersed nanofunctionalized DASA as an AuNP@PVA-DASA conjugate. The composite did not enhance the anti-growth effect of DASA on PDAC cell lines. The cell model with high LYN expression showed the strongest response to the therapy. We confirm deregulated Src kinetome activity as a prevalent feature of PDAC by revealing mRNA levels associated with higher malignancy grade of tumors. BLK (B lymphocyte kinase) expression predicts shorter overall survival of diabetic PDAC patients. Nanofunctionalization of DASA needs further improvement to overcome the therapy resistance of PDAC. LYN mRNA is augmented in tumors with higher malignancy and can serve as a predictive biomarker for the therapy resistance of PDAC cells against DASA. Studying the biological roles of BLK might help to identify underlying molecular mechanisms associated with PDAC in diabetic patients.

Dual modulation of blue-fluorescent carbon dots for simultaneous detection of topotecan and pantoprazole.

This study introduces a novel approach for the simultaneous determination of topotecan (TOP) and pantoprazole (PNT), two drugs whose interaction is critical in clinical applications. The significance of this study originates from the need to understand the pharmacokinetic changes of TOP after PNT administration, which can inform necessary dose adjustments of TOP. To achieve this, nitrogen blue emissive carbon dots (B@NCDs) were produced and employed due to their unique fluorescent properties. When TOP is added to B@NCDs, it exhibits strong native fluorescence at 545 nm without influencing the B@NCDs' fluorescence at 447 nm. Conversely, PNT causes quenching of B@NCDs fluorescence, a property that enables the distinct detection of both drugs. The B@NCDs were fully characterized using different techniques, including ultraviolet-visible spectrophotometry, fluorescence analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM), and FTIR spectroscopy. The proposed method demonstrated excellent linearity, selectivity, and sensitivity, with low detection limits (LOD, S/N = 3); 0.0016 μg mL-1 for TOP and 0.36 μg mL-1 for PNT. Applied to spiked rabbit plasma samples, this method offers a new approach for evaluating the pharmacokinetic interaction between TOP and PNT. It enables the determination of all pharmacokinetic parameters of TOP before and after coadministration with PNT, providing essential insights into whether dose adjustments are necessary. This research not only contributes to the field of drug monitoring and interaction studies but also exemplifies the potential of B@NCDs in complex biological matrices, paving the way for further pharmacological and therapeutic applications.

An in vivo appraisal of Punica granatum peel extract's ultrastructural effect on cystic echinococcosis in mice.

In the past decade, interest has significantly increased regarding the medicinal and nutritional benefits of pomegranate (Punica granatum) peel. This study examined the effects of using pomegranate peel extract (PGE) alone and in combination with albendazole (ABZ) on ultrastructural and immunological changes in cystic echinococcosis in laboratory-infected mice. Results revealed that the smallest hydatid cyst size and weight (0.48 ± 0.47mm, 0.17 ± 0.18 gm) with the highest drug efficacy (56.2%) was detected in the PGE + ABZ group, which also exhibited marked histopathological improvement. Ultrastructural changes recorded by transmission electron microscopy including fragmentation of the nucleus, glycogen depletion, and multiple lysosomes in vacuolated cytoplasm were more often observed in PGE + ABZ group. IFN-γ levels were significantly increased in the group treated with ABZ, with a notable reduction following PGE treatment, whether administered alone or in combination with ABZ. Thus, PGE enhanced the therapeutic efficiency of ABZ, with improvement in histopathological and ultrastructural changes.

A comparative and experimental study to evaluate the use of nanocontainer solutions for removing polymeric coatingsfrom glass artifacts

Purpose The purpose of this study is to evaluate the effectiveness of nanocontainer solutions in removing deteriorated and aged polymers commonly used in coating and consolidating archaeological glass. Design/methodology/approach This study focused on characterizing glass surfaces coated with two commonly used polymeric materials in archaeological glass preservation. Furthermore, the study evaluates the elimination of these coatings from the surfaces by using innovative aqueous systems composed of micellar solutions (MS) and oil-in-water (O/W) Texapon-P microemulsions (TEX). Glass samples coated with selected polymers were subjected to thermal and photochemical aging to simulate natural degradation conditions. This study aimed to evaluate the effectiveness of nanocontainer aqueous systems compared to acetone (Ac), a conventional solvent commonly used for removal procedures. The characterization procedures involved transmission electron microscopy, USB digital microscopy, scanning electron microscopy, color alteration and gravimetric measurement. Findings The findings indicate that the effectiveness of novel techniques using aqueous nanocontainer systems is quite promising when considering a “green approach” to preserving cultural heritage. Microscopic examination demonstrated the efficacy of MS in effectively removing acrylic and vinyl polymers from the glass surface. Furthermore, TEX proved effective in removing polyvinyl acetate (PVA) over Paraloid B72 (B-72). In addition, the measurement of color alteration values revealed a decrease after using MS compared to the standard sample before applying the polymers, with values of ΔE = 1.48 and 1.82 for B-72 polymer and PVA, respectively. Originality/value This research provides nanocontainer solutions for removing aged polymers from the glass surface. This makes the current study a promising step for treating archaeological glass.

A mandibular advancement device attenuates the abnormal morphology and function of mitochondria from the genioglossus in obstructive sleep apnea-hypopnea syndrome rabbits.

Obstructive sleep apnea hypopnea syndrome (OSAHS) is a serious and potentially life-threatening disease. Mandibular advancement device (MAD) has the characteristics of non-invasive, comfortable, portable and low-cost, making it the preferred treatment for mild-to-moderate OSAHS. Our previous studies found that abnormal contractility and fibre type distribution of the genioglossus could be caused by OSAHS. However, whether the mitochondria participate in these tissue changes is unclear. The effect of MAD treatment on the mitochondria of the genioglossus in OSAHS is also uncertain. To examine the morphology and function of mitochondria from the genioglossus in a rabbit model of obstructive sleep apnea-hypopnea syndrome (OSAHS), as well as these factors after insertion of a mandibular advancement device (MAD). Thirty male New Zealand white rabbits were randomised into three groups: control, OSAHS and MAD, with 10 rabbits in each group. Animals in Group OSAHS and Group MAD were induced to develop OSAHS by injection of gel into the submucosal muscular layer of the soft palate. The rabbits in Group MAD were fitted with a MAD. The animals in the control group were not treated. Further, polysomnography (PSG) and cone-beam computed tomography (CBCT) scan were used to measure MAD effectiveness. CBCT of the upper airway and PSG suggested that MAD was effective. Rabbits in the three groups were induced to sleep for 4-6 h per day for eight consecutive weeks. The genioglossus was harvested and detected by optical microscopy and transmission electron microscopy. The mitochondrial membrane potential was determined by laser confocal microscopy and flow cytometry. Mitochondrial complex I and IV activities were detected by mitochondrial complex assay kits. OSAHS-like symptoms were induced successfully in Group OSAHS and rescued by MAD treatment. The relative values of the mitochondrial membrane potential, mitochondrial complex I activity and complex IV activity were significantly lower in Group OSAHS than in the control group; however, there was no significant difference between Group MAD and the control group. The OSAHS-induced injury and the dysfunctional mitochondria of the genioglossus muscle were reduced by MAD treatment. Damaged mitochondrial structure and function were induced by OSAHS and could be attenuated by MAD treatment.

Effect of plate orientation on apparent thickness of mineral plates by transmission electron microscopy.

Transmission electron microscopy (TEM) is widely used to study the ultrastructure of bone. The mineral of bone occurs as polycrystalline mineral plates about 3 to 6 nm in thickness. A problem in using TEM to make quantitative analyses of bone is that the orientation of the plates with respect to the plane of the section being imaged is expected to affect their apparent thickness. The purpose of this study was to test if this was true, if the apparent thickness of plates changed substantially as a result of tilt of the section. We prepared TEM sections of samples of cortical human bone by ion beam milling, orienting one section parallel to the collagen fibril axes and one perpendicular to them. We obtained TEM bright field and HAADF images of these sections, tilting the sections up to ± 20° at 2° intervals and measuring the apparent thickness of individual mineral platelets at each angle of tilt. Thickness appears to double as section is tilted ± 20°. True thickness of plates is determined by tilting the section along an axis parallel to the plate orientation and determining the minimum apparent thickness. However, as plates are tilted away from minimum-thickness orientation, they become less well-resolved, disappearing when tilted more than 20°. We therefore also measured apparent thickness of only the darkest (most electron scattering) plate images in an untilted section and obtained the same average thickness as that obtained by tilting. We conclude that tilting of the section is not necessary to obtain an accurate measurement of the thickness of mineral plates.

Thermosensitive and mucoadhesive gels containing solid lipid nanoparticles loaded with fluconazole and niosomes loaded with clindamycin for the treatment of periodontal diseases: a laboratory experiment

BackgroundPeriodontal diseases may benefit more from topical treatments with nanoparticles rather than systemic treatments due to advantages such as higher stability and controlled release profile. This study investigated the preparation and characterization of thermosensitive gel formulations containing clindamycin-loaded niosomes and solid lipid nanoparticles (SLNs) loaded with fluconazole (FLZ), as well as their in vitro antibacterial and antifungal effects in the treatment of common microorganisms that cause periodontal diseases.MethodsThis study loaded niosomes and SLNs with clindamycin and FLZ, respectively, and assessed their loading efficiency, particle size, and zeta potential. The particles were characterized using a variety of methods such as differential scanning calorimetry (DSC), dynamic light scattering (DLS), and Transmission Electron Microscopy (TEM). Thermosensitive gels were formulated by combining these particles and their viscosity, gelation temperature, in-vitro release profile, as well as antibacterial and antifungal effects were evaluated.ResultsBoth types of these nanoparticles were found to be spherical (TEM) with a mean particle size of 243.03 nm in niosomes and 171.97 nm in SLNs (DLS), and respective zeta potentials of -23.3 and -15. The loading rate was 98% in niosomes and 51% in SLNs. The release profiles of niosomal formulations were slower than those of the SLNs. Both formulations allowed the release of the drug by first-order kinetic. Additionally, the gel formulation presented a slower release of both drugs compared to niosomes and SLNs suspensions.ConclusionThermosensitive gels containing clindamycin-loaded niosomes and/or FLZ-SLNs were found to effectively fight the periodontitis-causing bacteria and fungi.

Formation of nanophase metallic iron through charge disproportionation of ferrous iron during micrometeoroid impact‐induced splash melting

AbstractCharge disproportionation of ferrous iron has been considered as one of the mechanisms for the formation of metallic iron on the lunar surface. However, the detailed mechanism of the disproportionation reaction on the Moon is yet to be elucidated. We provide direct evidence for the ferrous disproportionation reaction that produces nano phase metallic iron (npFe0) during a rapid cooling process after splash melting from a lunar sample returned by China's Chang'e‐5 mission. Space weathering processes have resulted in the formation of three distinct zones at the rim of a pyroxene fragment, as observed through transmission electron microscopy. These zones, made up of splashed melts, newly formed melts from the substrate, and the mineral, are distinguished as I, II, and III. Quantitative analyses of the iron valence state by electron energy loss spectroscopy show that disproportionation reactions occurred in zone II at a low temperature of <570°C during a rapid cooling process. The reaction led to the production of α‐structure npFe0 and Fe3+ reserve in the glass phase. The npFe0 produced by the disproportionation reaction has a larger grain size than those formed from solar wind irradiation, implying that micrometeoroid impacts mainly contribute to the darkening of visible and near‐infrared reflectance. These findings reveal a novel rim structure by repeated space weathering and a universal formation mechanism of npFe0 during micrometeoroid impacts, suggesting that the disproportionation reaction could be widespread on airless bodies with impact‐induced splash processes.

Atomic-Scale Tracking Topological Phase Transition Dynamics of Polar Vortex-Antivortex Pairs.

Non-trivial topological structures, such as vortex-antivortex (V-AV) pairs, have garnered significant attention in the field of condensed matter physics. However, the detailed topological phase transition dynamics of V-AV pairs, encompassing behaviors like self-annihilation, motion, and dissociation, have remained elusive in real space. Here, we employ polar V-AV pairs as a model system and track their transition pathways with atomic-scale resolution, facilitated by in situ (scanning) transmission electron microscopy and phase field simulations. Our investigation reveals that polar vortices and antivortices can stably coexist as bound pairs at room temperature, and their polarization decreases with heating. No dissociation behavior is observed between the V-AV phase at room temperature and the paraelectric phase at high temperature. However, the application of electric fields can promote the approach of vortex and antivortex cores, ultimately leading to their annihilation near the interface. Revealing the transition process mediated by polar V-AV pairs at the atomic scale, particularly the role of polar antivortex, provides us new insights into understanding the topological phases of matter and their topological phase transitions. Moreover, the detailed exploration of the dynamics of polar V-AV pairs under thermal and electrical fields lays a solid foundation for their potential applications in electronic devices. This article is protected by copyright. All rights reserved.

Application of Intercritical Austenitizing in a Commercial CMnSi Steel as a Tool for Optimizing a One‐Step Quenching and Partitioning Cycle Aiming to Achieve a Third‐Generation Advanced High‐Strength Steel

Advanced high‐strength steels (AHSS) have been extensively studied to develop its third generation from relatively low‐cost alloys, but seeking optimized mechanical properties. In this context, the effects of quenching heat treatments are evaluated in this work after intercritical austenitizing (IA) on microstructure, alloying elements partitioning, and Ms temperature for a commercial CMnSi alloy. Applying dilatometric data and microstructural characterization, different heat cycles are evaluated. The obtained experimental results are compared with those ones obtained by computer simulations at equilibrium conditions. Based on this characterization, an optimized one‐step quenching and partitioning (Q&P) cycle (after IA) is proposed and applied to tensile test specimens. Then, the specimen microstructure is characterized by scanning and transmission electron microscopy as well as by X‐ray diffraction. Using the proposed methodology, it is possible to produce a Q&P steel with a product of tensile strength and elongation of 29.5 GPa% and a 7% volumetric fraction of retained austenite. It is concluded that the precise knowledge about the IA effects on the phase transformations and microstructure evolution in a commercial CMnSi alloy has great potential to be applied in defining a one‐step Q&P heat treatment that favors a multiphase microstructure, which meets mechanical properties requirements for a third‐generation AHSS.

Antennal chemoreceptors in the European ectoparasitoid Sclerodermus cereicollis (Hymenoptera: Bethylidae).

Sclerodermus cereicollis is a European flat wasp ectoparasitoid of some longhorn beetle species. This species is important as a suitable biological control agent against xylophagous pests. To better understand its chemical ecology, the ultrastructure of the antennal sensilla of the adult was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The sensilla are located mainly in the ventro-medial side of the antennae. We report a clearly sexual dimorphism with respect to antennae length, and to types, number, and distribution of chemosensilla. The antennae in males are significantly longer than those of females. We describe in detail the external and internal structure of different chemoreceptors represented by sensilla placodea, long sensilla basiconica, multiporous sensilla chaetica, grooved sensilla ampullacea, uniporous grooved sensilla chaetica. The potential involvement of the different kinds of chemoreceptors in inter- (mainly sexual recognition and social behavior-kin recognition) or intra-specific communication (mainly host selection) is discussed on the basis of behavioral and electrophysiological investigations performed on other parasitoid species belonging to the same family. Other sensilla with morphology that is not consistent with that of chemoreceptors are represented by grooved pegs, coeloconic pegs, trichoid sensilla. Such detailed ultrastructural investigation of the flagellar chemoreceptors of S. cereicollis, clarifying the number of chemosensory neurons innervating the different sensilla, is crucial for further electrophysiological investigations on this important species. RESEARCH HIGHLIGHTS: Evident sexual dimorphism concerning antennae length, type, number, and distribution of chemosensilla. Long sensilla basiconica (LSB) present only in females could play a role in host location and/or maternal care. Multiporous sensilla chaetica (MSC), significantly longer and mostly represented in males, could play a role in the perception of sexual pheromones. Detailed ultrastructural study is crucial for electrophysiological investigations on this important species.

Natural approach of using nisin and its nanoform as food bio-preservatives against methicillin resistant Staphylococcus aureus and E.coli O157:H7 in yoghurt

BackgroundNatural antimicrobial agents such as nisin were used to control the growth of foodborne pathogens in dairy products. The current study aimed to examine the inhibitory effect of pure nisin and nisin nanoparticles (nisin NPs) against methicillin resistant Staphylococcus aureus (MRSA) and E.coli O157:H7 during the manufacturing and storage of yoghurt. Nisin NPs were prepared using new, natural, and safe nano-precipitation method by acetic acid. The prepared NPs were characterized using zeta-sizer and transmission electron microscopy (TEM). In addition, the cytotoxicity of nisin NPs on vero cells was assessed using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The minimum inhibitory concentrations (MICs) of nisin and its nanoparticles were determined using agar well-diffusion method. Further, fresh buffalo’s milk was inoculated with MRSA or E.coli O157:H7 (1 × 106 CFU/ml) with the addition of either nisin or nisin NPs, and then the inoculated milk was used for yoghurt making. The organoleptic properties, pH and bacterial load of the obtained yoghurt were evaluated during storage in comparison to control group.ResultsThe obtained results showed a strong antibacterial activity of nisin NPs (0.125 mg/mL) against MRSA and E.coli O157:H7 in comparison with control and pure nisin groups. Notably, complete eradication of MRSA and E.coli O157:H7 was observed in yoghurt formulated with nisin NPs after 24 h and 5th day of storage, respectively. The shelf life of yoghurt inoculated with nisin nanoparticles was extended than those manufactured without addition of such nanoparticles.ConclusionsOverall, the present study indicated that the addition of nisin NPs during processing of yoghurt could be a useful tool for food preservation against MRSA and E.coli O157:H7 in dairy industry.

Surface exsolving perovskite ceramics as catalyst for microwave methane pyrolysis to co-generate hydrogen and carbon nanotube

In this study, we have successfully developed a novel surface exsolving perovskite ceramic, which demonstrates the ability to simultaneously generate COx-free hydrogen and carbon nanotubes (CNTs) through methane pyrolysis under the influence of microwave irradiation. We conducted an extensive survey and optimization of various perovskite materials specifically tailored for microwave applications. Among the materials investigated, nickel-doped strontium titanium oxide (STON) emerged as the most promising candidate, exhibiting both a satisfactory methane conversion rate and excellent responsiveness to microwave irradiation. Refinement of STON was carried out by fine-tuning the Ni content, optimizing the reduction dwell time, and adjusting the reduction temperature. Notably, SrTiNi0.08O3 (STON8), demonstrated an impressive initial methane conversion rate of up to 40%. Transmission Electron Microscopy (TEM) provided visual evidence of the correlation between Ni content and reduction temperature, with respect to the exsolved Ni metal particle size. This finding highlights the immense potential of surface exsolving perovskite ceramics as a highly effective catalyst for the simultaneous production of CNTs and COx-free hydrogen via methane pyrolysis under microwave irradiation. It represents a step forward in the field of catalytic materials and microwave-driven processes.

STAT3 phosphorylation at Tyr705 affects DRP1 (dynamin-related protein 1) controlled-mitochondrial fission during the development of apoptotic-resistance in pulmonary arterial endothelial cells.

The apoptosis-resistant pulmonary arterial endothelial cells (PAECs) are known to be major players in the pulmonary remodeling of pulmonary arterial hypertension (PAH) and exhibit an abnormal metabolic profile with mitochondrial dysfunction. Mitochondrial fission has been shown to regulate the apoptosis of several cell types, but this is largely unexplored in the PAECs. The roles of mitochondrial fission control by Dynamin related protein-1 (DRP1) in the development of PAECs apoptosis suppression were investigated in present study and the potential mechanisms behind this were furtherly explored. The mitochondrial morphology was investigated in PAECs from PAH rats with the pulmonary plexiform lesions, and the relations of it with DRP1 expression and apoptosis were furtherly identified in apoptosis-resistant PAECs induced by hypoxia. PAECs were isolated from rats with severe PAH and from normal subjects, the apoptotic-resistant PAECs were induced by hypoxia. DRP1 gene knockdown was achieved via DRP1-siRNA, DRP1 and STAT3 phosphorylation were blocked using its inhibitors, respectively. Apoptosis was analyzed by flow cytometry, and mitochondrial morphology was investigated by transmission electron microscope and confocal microscopy. The PAECs isolated from PAH rats with the pulmonary plexiform-like lesions and displayed lower apoptotic rate with increased DRP1 expression and mitochondrial fragmentation. In addition, similar observations were achieved in apoptosis-resistant PAECs induced by hypoxia. Targeting DRP1 using siRNA and pharmacologic blockade prevented the mitochondrial fission and subsequent apoptotic resistance in PAECs under hypoxia. Mechanistically, STAT3 phosphorylation at Tyr705 was shown to be activated in both PAH and hypoxia-treated PAECs, leading to the regulation of DRP1 expression. Of importance, targeting STAT3Tyr705 phosphorylation prevented DRP1 disruption on apoptosis in PAECs under hypoxia. These data indicated that STAT3 phosphorylation at Tyr705 impacted DRP1-controlled mitochondrial fission during the development of apoptosis-resistance in PAECs, suggesting mitochondrial dynamics may represent a therapeutic target for PAH.

Abnormally High Graphitic Crystallization of Cellulose Nanocrystals.

Cellulose nanocrystals (CNCs) are currently of great interest for many applications, such as energy storage and nanocomposites, because of their natural abundance. A number of carbonization studies have reported abnormal graphitization behavior of CNCs, although cellulose is generally known as a precursor for hard carbon (nongraphitizable carbon). Herein, we report a spray-freeze-drying (SFD) method for CNCs and a subsequent carbonization study to ascertain the difference in the structural development between the amorphous and crystalline phases. The morphological observation by high-resolution transmission electron microscopy of the carbonized SFD-CNC clearly shows that the amorphous and crystalline phases of CNC are attributed to the formation of hard and soft carbon, respectively. The results of a reactive molecular dynamics (RMD) study also show that the amorphous cellulose phase leads to the formation of fewer carbon ring structures, indicative of hard carbon. In contrast, the pristine crystalline cellulose phase has a higher density and thermal stability, resulting in limited molecular relaxation and the formation of a highly crystalline graphitic structure (soft carbon).

Precision anode vacancy engineering for long-lasting and fast-charging Na-Ion batteries

In the field of energy storage materials, the unique properties of vacancies are highly significant, especially in the optimization of transition metal dichalcogenides (TMDs). However, scaling up these storage solutions remains a considerable challenge. In our study, we successfully synthesized VSe2-x via alleviating selenide content, where vacancies were introduced in situ through a straightforward physical vapor transport process. These vacancies boost the adsorption capacity for sodium ions (Na+), and create additional active sites, thereby minimizing the structural changes in VSe2-x during Na+ storage. Our VSe2-x based negative electrode demonstrates impressive sodium storage capability, offering an exceptional rate performance with a capacity of 346 mAh g−1 at 5 A g−1 and maintaining a remarkable stability of 378 mAh g−1 even after 1400 cycles at 10 A g−1. Additionally, through a combination of theoretical calculations, in situ X-ray diffraction analysis, and ex situ transmission electron microscopy, we have confirmed the creation of vanadium selenide materials containing vacancies. During continuous charging and discharging, these materials facilitate the generation of numerous sodium-containing aggregates with high electronic conductivity. This paper provides a comprehensive exploration of how vacancies in transformed materials can be an effective strategy for efficient rechargeable batteries.

S‐Scheme g‐C3N4/CdS Heterostructures Grafting Single Pd Atoms for Ultrafast Charge Transport and Efficient Visible‐Light‐Driven H2 Evolution

AbstractEmerging step‐scheme (S‐scheme) heterostructures hold unique superiority in steering directional charge transport and reinforcing redox capacity, yet rational modification of S‐scheme heterostructures by single atoms (SAs) for efficient photocatalytic H2 evolution is rarely reported. In this work, Pd SAs‐modulated organic–inorganic g‐C3N4/CdS S‐scheme heterostructures are designed and prepared by a one‐pot mechanochemical approach allowing for g‐C3N4 nanosheets/CdS nanoparticles to confine atomically dispersed Pd co‐catalysts. The g‐C3N4/CdS S‐scheme charge‐transfer pathway is corroborated by a combination of in situ irradiated X‐ray photoelectron spectroscopy, electron paramagnetic resonance, and Kelvin probe force microscopy. Density functional theory (DFT) calculations, high‐angle annular dark‐field scanning transmission electron microscopy, and X‐ray absorption fine structure identify Pd‐S3 and Pd‐N2 atomic moieties underpinned by the electronic interaction between Pd SAs and g‐C3N4/CdS heterostructures, in which the d‐band center of Pd SAs is optimized for proton adsorption thermodynamically. Further, the g‐C3N4/CdS S‐scheme heterostructures alongside Pd SAs in concert boost the rapid migration of photogenerated electrons (1.05 ps) via Pd─S and Pd─N bond‐derived channels. A maximal H2 evolution rate of 85.66 mmol h−1 g−1 is achieved by 1 wt% Pd‐20 wt% g‐C3N4/CdS hierarchical composites. This work may guide the design of high‐efficiency S‐scheme‐based photocatalysts for solar‐to‐H2 conversion and beyond.