Spectroscopic and Computational Study of ZnCl2-Methanol Low-Melting-Temperature Mixtures

Alcoholic electrolyte mixtures have wide applications in industries. In this study, a series of mixtures composed of ZnCl2 and methanol (MeOH) with ZnCl2 mol % from 6.7 to 25 were prepared, and their spectral, structural, and thermodynamic properties were studied using infrared (IR) spectroscopy, differential scanning calorimetry (DSC), and density functional theory (DFT) calculations. The DFT-assisted analysis of excess spectra, supported by 2D-correlation spectroscopy, led to the identification of the major constituents of ZnCl2-MeOH mixtures, namely, MeOH monomer, MeOH dimer, and ZnCl2-3MeOH complex, produced after dissociation of MeOH trimer which represents the bulk methanol. The Hirshfeld charge analysis showed that in the competition between the O-H···Cl hydrogen bond (H-bond) and Zn ← O coordination bond to transfer charge in ZnCl2-MeOH complexes, the latter always dominates, making MeOH positively charged. The phase diagram of the binary system showed the presence of V-shaped glass transition temperatures (Tg), characteristic of low-melting mixture solvents (LoMMSs). The present study provides insights into the microscopic properties of the system and sheds light on the understanding of the general principles to prepare deep-eutectic solvents (DESs) or LoMMSs using inorganic salts and alcoholic compounds.

[Effects of cerium oxide nanoenzyme-gelatin methacrylate anhydride hydrogel in the repair of infected full-thickness skin defect wounds in mice]

Objective: To investigate the effects of cerium oxide nanoenzyme-gelatin methacrylate anhydride (GelMA) hydrogel (hereinafter referred to as composite hydrogel) in the repair of infected full-thickness skin defect wounds in mice. Methods: This study was an experimental study. Cerium oxide nanoenzyme with a particle size of (116±9) nm was prepared by hydrothermal method, and GelMA hydrogel with porous network structure and good gelling performance was also prepared. The 25 μg/mL cerium oxide nanoenzyme which could significantly promote the proliferation of human skin fibroblasts and had high superoxide dismutase activity was screened out. It was added to GelMA hydrogel to prepare composite hydrogel. The percentage of cerium oxide nanoenzyme released from the composite hydrogel was calculated after immersing it in phosphate buffer solution (PBS) for 3 and 7 d. The red blood cell suspension of mice was divided into PBS group, Triton X-100 group, cerium oxide nanoenzyme group, GelMA hydrogel group, and composite hydrogel group, which were treated with corresponding solution. The hemolysis of red blood cells was detected by microplate reader after 1 h of treatment. The bacterial concentrations of methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli were determined after being cultured with PBS, cerium oxide nanoenzyme, GelMA hydrogel, and composite hydrogel for 2 h. The sample size in all above experiments was 3. Twenty-four 8-week-old male BALB/c mice were taken, and a full-thickness skin defect wound was prepared in the symmetrical position on the back and infected with MRSA. The mice were divided into control group without any drug intervention, and cerium oxide nanoenzyme group, GelMA hydrogel group, and composite hydrogel group applied with corresponding solution, with 6 mice in each group. The wound healing was observed on 3, 7, and 14 d after injury, and the remaining wound areas on 3 and 7 d after injury were measured (the sample size was 5). The concentration of MRSA in the wound exudation of mice on 3 d after injury was measured (the sample size was 3), and the blood flow perfusion in the wound of mice on 5 d after injury was observed using a laser speckle flow imaging system (the sample size was 6). On 14 d after injury, the wound tissue of mice was collected for hematoxylin-eosin staining to observe the newly formed epithelium and for Masson staining to observe the collagen situation (the sample size was both 3). Results: After immersion for 3 and 7 d, the release percentages of cerium oxide nanoenzyme in the composite hydrogel were about 39% and 75%, respectively. After 1 h of treatment, compared with that in Triton X-100 group, the hemolysis of red blood cells in PBS group, GelMA hydrogel group, cerium oxide nanoenzyme group, and composite hydrogel group was significantly decreased (P<0.05). Compared with that cultured with PBS, the concentrations of MRSA and Escherichia coli cultured with cerium oxide nanoenzyme, GelMA hydrogel, and composite hydrogel for 2 h were significantly decreased (P<0.05). The wounds of mice in the four groups were gradually healed from 3 to 14 d after injury, and the wounds of mice in composite hydrogel group were all healed on 14 d after injury. On 3 and 7 d after injury, the remaining wound areas of mice in composite hydrogel group were (29±3) and (13±5) mm2, respectively, which were significantly smaller than (56±12) and (46±10) mm2 in control group and (51±7) and (38±8) mm2 in cerium oxide nanoenzyme group (with P values all <0.05), but was similar to (41±5) and (24±9) mm2 in GelMA hydrogel group (with P values both >0.05). On 3 d after injury, the concentration of MRSA on the wound of mice in composite hydrogel group was significantly lower than that in control group, cerium oxide nanoenzyme group, and GelMA hydrogel group, respectively (with P values all <0.05). On 5 d after injury, the volume of blood perfusion in the wound of mice in composite hydrogel group was significantly higher than that in control group, cerium oxide nanoenzyme group, and GelMA hydrogel group, respectively (P<0.05). On 14 d after injury, the wound of mice in composite hydrogel group basically completed epithelization, and the epithelization was significantly better than that in the other three groups. Compared with that in the other three groups, the content of collagen in the wound of mice in composite hydrogel group was significantly increased, and the arrangement was also more orderly. Conclusions: The composite hydrogel has good biocompatibility and antibacterial effect in vivo and in vitro. It can continuously sustained release cerium oxide nanoenzyme, improve wound blood perfusion in the early stage, and promote wound re-epithelialization and collagen synthesis, therefore promoting the healing of infected full-thickness skin defect wounds in mice.

[Research progress of long-chain non-coding RNA in lipid metabolism reprogramming in primary hepatocellular carcinoma]

Hepatocellular carcinoma (HCC) is the most common liver malignant tumor with complex pathogenesis and a poor prognosis. Metabolic reprogramming has been recognized as one of the important cancer markers, and the liver, as an important organ for lipid metabolism in the human body, plays an important role in the process of the occurrence and development of HCC. More and more evidence shows that long-chain non-coding RNA (lncRNA) can influence the lipid metabolism process by regulating key enzymes and transcription factors, as well as being involved in the occurrence and development of HCC. Therefore, explicating the mechanism of lncRNA in lipid metabolism reprogramming is conducive to providing new targets and strategies for the diagnosis and treatment and improving the prognosis of HCC patients. This article summarizes the latest research progress on the involvement of lncRNA in the reprogramming process of HCC lipid metabolism.

Atovaquone enhances antitumor efficacy of TCR-T therapy by augmentation of ROS-induced ferroptosis in hepatocellular carcinoma

T-cell receptor (TCR) engineered T-cell therapy has recently emerged as a promising adoptive immunotherapy approach for tumor treatment, yet hindered by tumor immune evasion resulting in poor therapeutic efficacy. The introduction of ferroptosis-targeted inducers offers a potential solution, as they empower T cells to induce ferroptosis and exert influence over the tumor microenvironment. Atovaquone (ATO) stands as a prospective pharmaceutical candidate with the potential to target ferroptosis, effectively provoking an excessive generation and accumulation of reactive oxygen species (ROS). In this study, we evaluated the effectiveness of a combination therapy comprising ATO and TCR-T cells against hepatocellular carcinoma (HCC), both in vitro and in vivo. The results of lactate dehydrogenase and cytokine assays demonstrated that ATO enhanced cytotoxicity mediated by AFP-specific TCR-T cells and promoted the release of IFN-γ in vitro. Additionally, in an established HCC xenograft mouse model, the combined therapy with low-dose ATO and TCR-T cells exhibited heightened efficacy in suppressing tumor growth, with no apparent adverse effects, comparable to the results achieved through monotherapy. The RNA-seq data unveiled a significant activation of the ferroptosis-related pathway in the combination therapy group in comparison to the TCR-T cells group. Mechanistically, the synergy between ATO and TCR-T cells augmented the release of IFN-γ by TCR-T cells, while concurrently elevating the intracellular and mitochondrial levels of ROS, expanding the labile iron pool, and impairing the integrity of the mitochondrial membrane in HepG2 cells. This multifaceted interaction culminated in the potentiation of ferroptosis within the tumor, primarily induced by an excess of ROS. In summary, the co-administration of ATO and TCR-T cells in HCC exhibited heightened vulnerability to ferroptosis. This heightened susceptibility led to the inhibition of tumor growth and the stimulation of an anti-tumor immune response. These findings suggest that repurposing atovaquone for adoptive cell therapy combination therapy holds the potential to enhance treatment outcomes in HCC.

Heat stress-associated changes in the intestinal barrier, inflammatory signals, and microbiome communities in dairy calves

Recent studies indicate that heat stress pathophysiology is associated with intestinal barrier dysfunction, local and systemic inflammation, and gut dysbiosis. However, inconclusive results and a poor description of tissue-specific changes must be addressed to identify potential intervention targets against heat stress illness in growing calves. Therefore, the objective of this study was to evaluate components of the intestinal barrier, pro- and anti-inflammatory signals, and microbiota community composition in Holstein bull calves exposed to heat stress. Animals (mean age = 12 wk old; mean body weight = 122 kg) penned individually in temperature-controlled rooms were assigned to (1) thermoneutral conditions (constant room temperature at 19.5°C) and restricted offer of feed (TNR, n = 8), or (2) heat stress conditions (cycles of room temperatures ranging from 20 to 37.8°C) along with ad libitum offer of feed (HS, n = 8) for 7 d. Upon treatment completion, sections of the jejunum, ileum, and colon were collected and snap-frozen immediately to evaluate gene and protein expression, cytokine concentrations, and myeloperoxidase activity. Digesta aliquots of the ileum, colon, and rectum were collected to assess bacterial communities. Plasma was harvested on d 2, 5, and 7 to determine cytokine concentrations. Overall, results showed a section-specific effect of HS on intestinal integrity. Jejunal mRNA expression of TJP1 was decreased by 70.9% in HS relative to TNR calves. In agreement, jejunal expression of heat shock transcription factor-1 protein, a known tight junction protein expression regulator, decreased by 48% in HS calves. Jejunal analyses showed that HS decreased concentrations of IL-1α by 36.6% and tended to decrease the concentration of IL-17A. Conversely, HS elicited a 3.5-fold increase in jejunal concentration of anti-inflammatory IL-36 receptor antagonist. Plasma analysis of pro-inflammatory cytokines showed that IL-6 decreased by 51% in HS relative to TNR calves. Heat stress alteration of the large intestine bacterial communities was characterized by increased genus Butyrivibrio_3, a known butyrate-producing organism, and changes in bacteria metabolism of energy and AA. A strong positive correlation between the rectal temperature and pro-inflammatory Eggerthii spp. was detected in HS calves. In conclusion, this work indicates that HS impairs the intestinal barrier function of jejunum. The pro- and anti-inflammatory signal changes may be part of a broader response to restore intestinal homeostasis in jejunum. The changes in large intestine bacterial communities favoring butyrate-producing organisms (e.g., Butyrivibrio spp.) may be part of a successful response to maintain the integrity of the colonic mucosa of HS calves. The alteration of intestinal homeostasis should be the target for heat stress therapies to restore biological functions, and, thus highlights the relevance of this work.

[Research progress of non-coding RNA-encoding polypeptides in primary hepatocellular carcinoma]

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors, with rapid progression and a poor prognosis. More and more studies have shown that there are small open reading frames (sORFs) on the molecular sequences of a large number of non-coding RNAs (ncRNAs), which can encode conserved peptides that play an important role in controlling the occurrence and development of HCC. This article introduces the discovery, prediction, and validation methods of ncRNA-encoding polypeptides and reviews its research progress, with the aim of providing new targets and ideas for early-stage diagnosis, targeted therapy, and prognosis assessment of HCC.

Strong Electron Transfer in Covalently Integrating Cu(I)-Organic Frameworks Enabling Effective Radionuclide Capture

Rational construction of strong electron-transfer materials remains a challenging task. Herein, we show a design rule for the construction of strong electron-transfer materials through covalently integrating electron-donoring Cu(I) clusters and electron-withdrawing triazine monomers together. As expected, Cu-CTF-1 (Cu(I)-triazine framework) was found to enable strong electron transfer up to 0.46|e| from each Cu(I) metal center to each adjacent triazine fragment. This finally leads to good spatial separation in both photogenerated electron-hole pairs and function units for photocatalytic uranium reduction under ambience and no sacrificial agent and to good charge separation of [I+][I5-] for I2 immobilization under extremely rigorous conditions. The results have not only opened up a structural design principle to access electron-transfer materials but also solved several challenging tasks in the field of radionuclide capture and CTFs.

A Novel Strategy for the Characterization of Self-Assembled Structures Using the Static Solid-State Phosphorus Nuclear Magnetic Resonance Technique

Structural characterization of assemblies in solutions is essential for understanding the relationship between the structure and material properties. In this study, we introduce a novel approach to investigate amphiphilic self-assemblies in solutions using the phospholipid molecule 1-palmitoyl-2-hydroxy-sn-glycero-3-phosphocholine (Lyso PC) as a 31P NMR probe. The high natural abundance and gyromagnetic ratio of 31P make it one of the most sensitive nuclei in the low-frequency region, enabling efficient detection even in dilute solutions. Lyso PC can readily co-assemble with amphiphilic molecules and ions in aqueous solutions, forming various structures, such as hexagonal, lamellar, and micellar assemblies. The characteristic line shapes of these assemblies reflect the chemical environment around the probe and provide insights into the different phase states of the assemblies. This strategy offers a simple, cost-effective, and static method for obtaining structural information about various assemblies. Our work not only introduces a sensitive probe for characterizing assemblies in a solvent environment but also inspires new ideas for the development of similar spectroscopic probes.

A Cholecystokinin Analogue Ameliorates Cognitive Deficits and Regulates Mitochondrial Dynamics via the AMPK/Drp1 Pathway in APP/PS1 Mice

BACKGROUND

There are no drugs on the market that can reverse or slow Alzheimer's disease (AD) progression. A protease-resistant Cholecystokinin (CCK) analogue used in this study is based on the basic structure of CCK, which further increases the stability of the peptide fragment and prolongs its half-life in vivo. We observed a neuroprotective effect of CCK-8L in APPswe/PS1dE9 (APP/PS1) AD mice. However, its corresponding mechanisms still need to be elucidated.

OBJECTIVE

This study examined CCK-8L's neuroprotective effects in enhancing cognitive impairment by regulating mitochondrial dynamics through AMPK/Drp1 pathway in the APP/PS1 AD mice.

METHODS

Behavioural tests are applied to assess competence in cognitive functions. Transmission electron microscopy (TEM) was performed to observe the ultrastructure of mitochondria of hippocampal neurons, Immunofluorescent staining was employed to assay for Aβ1-42, APP, Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and dynamin-related protein1 (Drp1). CRISPR/Cas9 was utilized for targeted knockout of the CCKB receptor (CCKBR) in the mouse APP/PS1 hippocampal CA1 region. A model of lentiviral vector-mediated overexpression of APP in N2a cells was constructed.

RESULTS

In vivo, experiments revealed that CCK analogue and liraglutide significantly alleviated cognitive deficits in APP/PS1 mice, reduced Aβ1-42 expression, and ameliorated l damage, which is associated with CCKBR activation in the hippocampal CA1 region of mice. In vitro tests showed that CCK inhibited mitochondrial fission and promoted fusion through AMPK/Drp1 pathway.

CONCLUSIONS

CCK analogue ameliorates cognitive deficits and regulates mitochondrial dynamics by activating the CCKB receptor and the AMPK/Drp1 pathway in AD mice.

A Static Damage Constitutive Model of Concrete Based on Microscopic Damage Mechanism

In this article, a microscopic constitutive model is established that includes friction, plastic, and spring elements and has clear physical meaning. The friction unit reflects the mutual friction between crack surfaces, the plastic unit reflects the development of concrete plasticity, and the fracture of the spring unit reflects the formation and expansion of interior cracks in concrete. In addition, the integration of the random field theory into this model uncovers the physical underpinnings of the relationship between concrete's nonlinearity and randomness. The multi-scale modeling of the concrete static damage constitutive model is then realized once the parameters of the random field are discovered using the macro test results. In order to apply the model's applicability in finite element programs, a subroutine was ultimately constructed. The experimental data and the anticipated values from the numerical simulation are in good agreement, supporting the model's realism.

Fatigue Reliability Assessment of RC Beams in Heavy-Haul Railways Based on Point Estimate Method

Heavy-haul railways have a high passing frequency of trains with a large axle weight, causing rapid accumulation of fatigue damage in reinforced concrete (RC) bridge structures, which significantly affects the safety of the bridges. To study the fatigue reliability of RC beams in heavy-haul railways, the fatigue performance function for RC beams in heavy-haul railways was established, and the fatigue reliability assessment method for bridge structures in heavy-haul railways based on the point estimate method (PEM) was developed. An 8 meter-span plate beam in an existing heavy-haul railway illustrates the method. The train axle weight and dynamic coefficient were considered random variables, and the first four moments of equivalent stress ranges were obtained. The traffic quantity of the heavy-haul railways was investigated, and the fatigue reliability was evaluated using the proposed method. In addition, the effects of annual freight volume and train axle weight on fatigue reliability were discussed. Results indicate that PEM can effectively and accurately evaluate the fatigue reliability of RC beams in heavy-haul railways. In the first 20 years of operation, the fatigue failure probability was less than the limit value specified in the standard. The increase in annual traffic volume and train axle weight will cause a significant increase in fatigue failure probability. The research results of this paper are expected to provide an important basis for the design and maintenance of reinforced concrete bridges for heavy-haul railways in the future.

Tissue-resident alveolar macrophages reduce O3-induced inflammation via MerTK mediated efferocytosis

Lung inflammation, caused by acute exposure to ozone (O3) - one of the six criteria air pollutants - is a significant source of morbidity in susceptible individuals. Alveolar macrophages (AMØs) are the most abundant immune cells in the normal lung and their number increases following O3 exposure. However, the role of AMØs in promoting or limiting O3-induced lung inflammation has not been clearly defined. Here, we used a mouse model of acute O3 exposure, lineage tracing, genetic knockouts, and data from O3-exposed human volunteers to define the role and ontogeny of AMØs during acute O3 exposure. Lineage tracing experiments showed that 12, 24, and 72 h after exposure to O3 (2 ppm) for 3h all AMØs were tissue-resident origin. Similarly, in humans exposed to FA and O3 (200 ppb) for 135 minutes, we did not observe ~21h post-exposure an increase in monocyte-derived AMØs by flow cytometry. Highlighting a role for tissue-resident AMØs, we demonstrate that depletion of tissue-resident AMØs with clodronate-loaded liposomes led to persistence of neutrophils in the alveolar space after O3 exposure, suggesting that impaired neutrophil clearance (i.e., efferocytosis) leads to prolonged lung inflammation. Moreover, depletion of tissue-resident AMØ demonstrated reduced clearance of intratracheally instilled apoptotic Jurkat cells, consistent with reduced efferocytosis. Genetic ablation of MerTK - a key receptor involved in efferocytosis - also resulted in impaired clearance of apoptotic neutrophils followed O3 exposure. Overall, these findings underscore the pivotal role of tissue-resident AMØs in resolving O3-induced inflammation via MerTK-mediated efferocytosis.

Neutral MOF Anion Receptor: Radical-Promoted Precise Anion Recognition

Precise ion recognition plays a key role in the anionic decontamination in water. However, the established anionic recognition based on neutral or cationic anion receptor is still restricted by the inherent limitation, such as narrow application scope in organic solvent rather than water for neutral anion receptor and poor selectivity due to non-directional electrostatic interaction for cationic anion receptor. Herein, for the first time, a neutral metal-organic framework (MOF) anion receptor is shown, enabling precise anion recognition, for example, the presence of a variety of 1000-fold competitive anions does not affect the selective adsorption of the target anion at all. A radical-dominating anion-recognition mechanism is proposed for rationalizing the efficacy of the neutral MOF.

CREB3L2 Regulates Hemidesmosome Formation during Epithelial Sealing

The long-term success rate of dental implants can be improved by establishing a favorable biological sealing with a high-quality epithelial attachment. The application of mesenchymal stem cells (MSCs) holds promise for facilitating the soft tissue integration around implants, but the molecular mechanism is still unclear and the general application of MSC sheet for soft tissue integration is also relatively unexplored. We found that gingival tissue-derived MSC (GMSC) sheet treatment significantly promoted the expression of hemidesmosome (HD)-related genes and proteins in gingival epithelial cells (GECs). The formation of HDs played a key role in strengthening peri-implant epithelium (PIE) sealing. Further, high-throughput transcriptome sequencing showed that GMSC sheet significantly upregulated the PI3K/AKT pathway, confirming that cell adhesion and HD expression in GECs were regulated by GMSC sheet. We observed that the expression of transcription factor CREB3L2 in GECs was downregulated. After treatment with PI3K pathway inhibitor LY294002, CREB3L2 messenger RNA and protein expression levels were upregulated. Further experiments showed that overexpression or knockdown of CREB3L2 could significantly inhibit or promote HD-related genes and proteins, respectively. We confirmed that CREB3L2 was a transcription factor downstream of the PI3K/AKT pathway and participated in the formation of HDs regulated by GMSC sheet. Finally, through the establishment of early implant placement model in rats, we clarified the molecular function of CREB3L2 in PIE sealing as a mechanical transmission molecule in GECs. The application of GMSC sheet-implant complex could enhance the formation of HDs at the implant-PIE interface and decrease the penetration distance of horseradish peroxidase between the implant and PIE. Meanwhile, GMSC sheet reduced the length of CREB3L2 protein expression on PIE. These findings elucidate the potential function and molecular mechanism of MSC sheet regulating the epithelial sealing around implants, providing new insights and ideas for the application of stem cell therapy in regenerative medicine.

Principal Component Analysis to Design Planning Target Volume in Oropharyngeal Cancers

PURPOSE/OBJECTIVE(S)

Standard translational shifts of the Clinical Target volume (CTV) to generate the Planning Target Volume (PTV) do not account for rotations. Head and neck positional misalignments derive in large part from rotations due to cervical spine arching and twisting in Cone Beam Computed Tomography (CBCT). Translational expansions do not track rotations, yielding coverage envelopes that unnecessarily overlap with adjacent structures. This work examines whether principal component analysis of the motion along all 6 degrees of freedom may be used to produce a more favorable PTV.

MATERIALS/METHODS

Seventy-five CBCTs of ten oropharyngeal cases were included. The records of couch shifts needed to align individual bony structures (C1-5, mandible and mastoid) between the planning image and CBCTs were recorded. A Principal Component Analysis of the shifts was used to generate an ellipsoid inflation of each CTV vertex along 6 degrees of freedom. The result was compared to a 3D ellipsoid based translational expansion, and to a described ellipsoid based vertex expansion along 6 degrees of freedom, with axes oriented in parallel to the treatment reference frame.

RESULTS

Themean (x, y) shifts in mm needed to align individually bodies C1 - C5 were respectively (-0.4, 0.5), (+.5, -0.2), (+-0.2, -0.2), (-0.2, +0.4), and (-0.5, +0.7), the monophasic pattern showing acquired curvature along both axes during treatment and demanding a PTV for coverage. A PTV was constructed using a described 6D ellipsoidal based boundary point expansion aligned along the reference frame axis or using a new theory to align against the principal components of the motion. A cyclical one-out method was used to validate the PTV models. Selected confidence intervals yielded complete coverage in >80% weeks in 80% cases. Validation testing disclosed similar complete coverage in 83-86% weekly CBCTs in the test cases with either method. The PCA 6D PTV could yield less normal structure overlap. A one out method was used to test overlap avoidance from PTVs constructed from a population of weekly CBCTs drawn from seven cases with one excluded. PTVs were drawn around target and constrictors on an extraneous case and imaged on a CT slice. Both a rolling 'ball' expansion of the vertices that applies a 3D translational ellipsoid and a PTV constructed using a 6D ellipsoid aligned against the standard reference frame overlapped with all or nearly all the constrictors in all but one trial (1/7). The 6D ellipsoid aligned against the principal motion components spared >70% of a constrictor in all trials (7/7).

CONCLUSION

PTVs remain needed to ensure target coverage in head and neck radiotherapy even with daily CT accuracy because of acquired spinal curvatures resulting in rotational displacements. A described 6D ellipsoid oriented to the reference frame can yield good coverage, but with unneeded constrictor coverage. A PCA analysis yields a PTV with equally good coverage but able to spare 70% of a constrictor.

Influence of Reflective Coating on Temperature Field and Temperature Effect of CRTS III Slab Ballastless Tracks on Bridges

To minimize the adverse effects of high temperatures on the service performance of track structures, research on the application of reflective coatings on track structures is urgently needed. Based on meteorological data and the characteristics of the multi-layer structure of the ballastless track, refined finite element models (FEMs) for the temperature field and temperature effect analysis of the CRTS III slab ballastless track structure on bridges were established. The temperature deformation characteristics and temperature stress distribution of the CRTS III slab ballastless track under natural environmental conditions were investigated. Similarly, the influence of a reflective coating on the structural temperature field and temperature effect was studied. The results showed that the temperature and vertical temperature gradient of the track slab were significantly reduced after the application of the reflective coating. Meanwhile, the thermal deformation and thermal stresses of the track slab and the self-compacting concrete (SCC) layer were minimized. Under high-temperature conditions in summer, the maximum temperature of the track slab decreased from 47.0 °C to 39.6 °C after the application of the reflective coating, and the maximum vertical temperature gradient of the track slab decreased from 61.5 °C/m to 39.1 °C/m after the application of the reflective coating. Under the maximum positive temperature gradient, the peak displacement of the upper arch in the middle of the slab and the peak displacement of the sinking in the slab corner decreased from 0.814 mm and 1.240 mm to 0.441 mm and 0.511 mm, respectively, and the maximum transverse tensile stresses of the track slab reduced from 2.7 MPa to 1.5 MPa as well. In addition, the reflective coating could also inhibit the failure of the interlayer interface effectively. The results of this study can provide a theoretical basis and reference for the application of reflective coatings on ballastless tracks on bridges.

Twisting, untwisting, and retwisting of elastic Co-based nanohelices

The reversible transformation of a nanohelix is one of the most exquisite and important phenomena in nature. However, nanomaterials usually fail to twist into helical crystals. Considering the irreversibility of the previously studied twisting forces, the reverse process (untwisting) is more difficult to achieve, let alone the retwisting of the untwisted crystalline nanohelices. Herein, we report a new reciprocal effect between molecular geometry and crystal structure which triggers a twisting-untwisting-retwisting cycle for tri-cobalt salicylate hydroxide hexahydrate. The twisting force stems from competition between the condensation reaction and stacking process, different from the previously reported twisting mechanisms. The resulting distinct nanohelices give rise to unusual structure elasticity, as reflected in the reversible change of crystal lattice parameters and the mutual transformation between the nanowires and nanohelices. This study proposes a fresh concept for designing reversible processes and brings a new perspective in crystallography.

Experimental Study on the Influence of Transverse Crack on Chloride Ingress in Concrete Slab Track of High-Speed Railway

The concrete track slab and the base slab of the high-speed railway CRTS II track structure are prone to transverse cracks in the initial service period, which are subjected to environmental action and train load. In order to investigate the influence of transverse cracks on chloride ingress of concrete track slab and base slab in a coastal environment, drying-wetting cycle chloride erosion tests were carried out on reinforced concrete track slab and base slab specimens with cracks ranging from 0 mm to 0.6 mm, subjected to continuous bending moment. The chloride ion concentration of concrete along the depth direction was collected during the test process. The experimental results show that the chloride ion concentration of concrete at the crack section is much higher than that at the intact section, and it increases with the increase of crack width in the range of 0.2 mm to 0.6 mm. A chloride diffusion coefficient model of cracked concrete is proposed for slab track based on the experimental results, which can comprehensively consider the effects of surface chloride ion concentration, chloride binding effect, time-varying effect, temperature, relative humidity, and transverse crack width.

Sulfonic-Pendent Vinylene-Linked Covalent Organic Frameworks Enabling Benchmark Potential in Advanced Energy

Both proton exchange membrane fuel cells and uranium-based nuclear techniques represent two green and advanced energies. However, both of them still face some intractable scientific and industrial problems. For the former, established proton-conduction materials always suffer one or another defect such as low proton conductivity, high activation energy, bad durability, or just small-scale product; while for the later, there still lacks available adsorbent to selectively recover of UO₂ ²⁺ from concentrated nitric acid (>1 M) during the spent fuel reprocessing due to the deactivation of the adsorption site or the decomposition of adsorbent under such rigorous conditions. It is found that the above two issues can be well solved by the construction of sulfonic-pendent vinylene-linked covalent organic frameworks (COFs), since these COFs contain abundant sulfonic units for both intrinsic proton conduction and UO₂ ²⁺ capture through strong coordination fixation and vinylene linkage that enhances the stability up to 12 M nitric acid (one of the best materials surviving in 12 M HNO₃ ).

Experimental Investigation of Seismic Performance of Precast Concrete Wall-Beam-Slab Joints with Overlapping U-Bar Loop Connections

In the era of energy conservation and environmental protection, as well as the industrialization of buildings, precast concrete (PC) structures have been developed and increasingly applied in construction industries due to their advantages of outstanding workability and ecofriendliness. In order to verify the reliability of overlapping U-bar loop connections and a modified form of these connections, and study the seismic performance of PC wall-beam-slab joints with these connection methods, three full-scale wall-beam-slab joints were designed and tested under low reversed cyclic loading, including one cast-in-place (CIP) specimen and two PC specimens. Based on the test results, the seismic performance of the PC joints was studied by comparing their damage process, hysteretic loops and skeleton curves, load-carrying capacity, ductility, equivalent stiffness, and energy dissipation with those of the CIP joint. After analyzing the experimental results, the following conclusions can be drawn: the overlapping U-bar loop connection and its modified form are effective and reasonable; the specimen with the modified connection form showed slightly better mechanical properties; the failure mode of the PC joints was consistent with that of the CIP joint; and the generation, distribution, and development of cracks in the PC specimens were similar to those in the CIP specimen. In addition, the stiffness of the PC joints was similar to that of the CIP joint, and the load-carrying capacity, ductility, and energy dissipation of the PC joints were better than those of the CIP joint. Moreover, the research in this paper can also provide some guidance for assembling wall-beam-slab joints in PC shear wall structures.

Unveiling the Surface Structure of ZnO Nanorods and H2 Activation Mechanisms with 17O NMR Spectroscopy

ZnO plays a very important role in many catalytic processes involving H₂, yet the details on their interactions and H₂ activation mechanism are still missing, owing to the lack of a characterization method that provides resolution at the atomic scale and follows the fate of oxide surface species. Here, we apply ¹⁷O solid-state NMR spectroscopy in combination with DFT calculations to unravel the surface structure of ZnO nanorods and explore the H₂ activation process. We show that six different types of oxygen ions in the surface and subsurface of ZnO can be distinguished. H₂ undergoes heterolytic dissociation on three-coordinated surface zinc and oxygen ions, while the formed hydride species migrate to nearby oxygen species, generating a second hydroxyl site. When oxygen vacancies are present, homolytic dissociation of H₂ occurs and zinc hydride species form from the vacancies. Reaction mechanisms on oxide surfaces can be explored in a similar manner.