Structural Maturation Research Articles

Soot particle morphology and polycyclic aromatic hydrocarbons formation molecular dynamics during diffusion combustion of three pentanol biofuels

Soot particles constitute a major pollutant in engine diffusion combustion, posing a serious threat to human health and the atmospheric environment. The employment of carbon-neutral biofuel, pentanol, in engines contributes to reducing soot emissions; however, its effectiveness is contingent upon the position of the OH functional group. This work investigated the soot morphology and microstructural parameters evolution of three pentanol isomers, and explored the influence mechanism of OH functional group positional isomerism on the entire process of PAHs formation at the atomic level. The results showed that the peak of primary particle size and soot volume fraction in pentanol flames showed a trend of 2-pentanol>3-pentanol>1-pentanol, and the initial formation time of soot in 1-pentanol flame is the latest, and the particle aggregate size is the smallest. The entire process of pentanol isomers soot formation can be divided into four stages: fuel pyrolysis forming initial ring, PAHs growing into initial soot, soot chain growth and structural evolution, soot morphology transformation and maturation. Among the three isomers, 2-pentanol has the fastest initial ring formation rate, the highest peak C-number in the largest molecule, and ultimately forms a more mature fullerene-like structure. 1-pentanol has the slowest initial ring formation rate, the lowest peak C-number in the largest molecule, ultimately forms a lower maturity layered structure. In terms of reaction pathways, H-atom abstraction and dehydroxylation reactions jointly dominate the initial decomposition pathway in 1-pentanol combustion, while in 2-pentanol, dehydroxylation becomes the main initial decomposition pathway due to the high stability of H atoms on β‑carbon. The dehydroxylation reaction tends to generate olefins, promoting the generation of C1-C4 hydrocarbon. The oxygen atom bonded on the α‑carbon site exhibits a stronger carbon fixation ability, and C1-C4 hydrocarbons are more inclined to participate in oxidation to form CO rather than promote the soot production.

Metabolic reprogramming via mitochondrial delivery for enhanced maturation of chemically induced cardiomyocyte-like cells.

Heart degenerative diseases pose a significant challenge due to the limited ability of native heart to restore lost cardiomyocytes. Direct cellular reprogramming technology, particularly the use of small molecules, has emerged as a promising solution to prepare functional cardiomyocyte through faster and safer processes without genetic modification. However, current methods of direct reprogramming often exhibit low conversion efficiencies and immature characteristics of the generated cardiomyocytes, limiting their use in regenerative medicine. This study proposes the use of mitochondrial delivery to metabolically reprogram chemically induced cardiomyocyte-like cells (CiCMs), fostering enhanced maturity and functionality. Our findings show that mitochondria sourced from high-energy-demand organs (liver, brain, and heart) can enhance structural maturation and metabolic functions. Notably, heart-derived mitochondria resulted in CiCMs with a higher oxygen consumption rate capacity, enhanced electrical functionality, and higher sensitivity to hypoxic condition. These results are related to metabolic changes caused by increased number and size of mitochondria and activated mitochondrial fusion after mitochondrial treatment. In conclusion, our study suggests that mitochondrial delivery into CiCMs can be an effective strategy to promote cellular maturation, potentially contributing to the advancement of regenerative medicine and disease modeling.

Clinical significance of tertiary lymphoid structure maturity in colorectal cancer patients.

To explore the clinical significance of the maturation of tertiary lymphoid structures (TLS) in colorectal cancer patients. A total of 230 surgical removed colorectal cancer specimens with detailed follow-up data were collected from Yinzhou Second Hospital. There were 128 cases of mature TLS and 108 cases of immature TLS according to immunohistochemical results. The patient age, gender, maximum tumor diameter, tumor location, differentiation degree, depth of invasion, lymph node metastasis, vascular tumor thrombus, liver metastasis, distant non-liver metastasis, mismatch repair status, expression of Ki-67, P53 and programmed cell death ligand 1 (PD-L1) were analyzed. The Kaplan-Meier method (Breslow test) was used to analyze the survival of patients, and multivariate Cox regression model was applied to analyze the prognostic factors. Compared to the immature TLS group, the mature TLS group showed a significantly lower rate of vascular tumor thrombus, lymph node metastasis, and liver metastasis. Additionally, the positive expression rate of Ki-67 was markedly reduced, while the rate of deficient mismatch repair and the positive expression rate of PD-L1 were significantly increased (all P<0.05). The overall survival rate of the mature TLS group was superior to that of the immature TLS group (Breslow=4.553, P<0.05). Cox regression analysis indicated that lymph node metastasis was an independent risk factor for the prognosis of colorectal cancer patients (P<0.01), while TLS maturation was a protective factor (P<0.05). The formation of TLS may play a significant role in inhibiting lymph node metastasis, liver metastasis, and vascular tumor thrombus in colorectal cancer, and patients with mature TLS have a favorable clinical prognosis, which can provide a reference for the immunotherapy and prognostic assessment of colorectal cancer patients.

Pan-immune-inflammation value predicts immunotherapy response and reflects local antitumor immune response in rectal cancer.

The pan-immune-inflammation value reflects the systemic inflammatory response, and tumor-infiltrating lymphocytes indicate a local immune response in rectal cancer. However, the association between systemic inflammatory response, as indicated by the pan-immune-inflammation value, and local immune responses in rectal cancer remains unclear. This study analyzed 915 treatment-naïve rectal cancer patients from the Peking Union Medical College Hospital and PLA General Hospital (PLAGH) cohorts who underwent radical surgery to investigate the relationship between the pan-immune-inflammation value and immune responses. Lower pan-immune-inflammation value was significantly associated with improved disease-free survival and cancer-specific survival. Multivariate Cox regression models identified the pan-immune-inflammation value as an independent prognostic factor. In the PLAGH cohort, patients with low pan-immune-inflammation values had higher immune cell levels, activated immune pathways, and increased expression of immune checkpoint genes according to RNA sequencing. Hematoxylin and eosin staining and immunohistochemical analysis revealed that lower pan-immune-inflammation value was associated with higher tumor-infiltrating lymphocyte density, more mature tertiary lymphoid structures, increased CD8+ T cells, and elevated human lymphocyte antigen class I expression. Conversely, patients with high pan-immune-inflammation values exhibited pathways linked to tumor progression, such as angiogenesis, epithelial-mesenchymal transition, hypoxia, KRAS signaling, and TGF-ß signaling. Among patients receiving anti-PD-1 therapy, responders had low pre- and post-treatment pan-immune-inflammation values. The pan-immune-inflammation value is a reliable marker associated with distinct immune microenvironment characteristics and can effectively predict disease-free survival, cancer-specific survival, and response to immunotherapy.

Effects of sectoral and aggregate uncertainty on corporate debt structure

PurposeThis paper investigates the differential and interactive effects of sectoral and aggregate uncertainty on the corporate debt structure of credit-constrained and credit-unconstrained firms in India.Design/methodology/approachThe panel fixed-effect model was used to examine the effect of sectoral and aggregate uncertainty on corporate debt structure using annual data of 2,405 firms from 1997 to 2020.FindingsAn increase in sectoral and aggregate uncertainty leads to a greater increase in total and short-term debt and a decrease in long-term debt for credit-constrained firms than in unconstrained ones. However, sectoral uncertainty affects firms’ debt maturity structure more than aggregate uncertainty. Credit-constrained firms use short-term debt to finance capital expenditure during periods of high sectoral uncertainty and working capital requirements during periods of high aggregate uncertainty. When both sectoral and aggregate uncertainty are high, credit-constrained firms decrease total and short-term debt usage more than credit-unconstrained firms do. Our results are robust to a variety of tests, such as different measures of uncertainty, the use of instrument variables and controlling for economic conditions and financial crises.Originality/valueThis study addresses the differential and interactive effects of sectoral and aggregate uncertainty on corporate debt structure.

Developing of a Digital Twin for Urban Planning in an International Context

The digital twin, adapted to the needs of urban planning and monitoring systems, is the subject of research and development in the academic, commercial and public sectors. The article provides international context in conceptual and practical implementation through their maturity level, scope, purpose, structure, input, processing features and output. The City of Zagreb is presented as an example of the implementation of GIS and 3D city models in urban planning, with activities towards a digital twin city. Based on research and local specifics, the concept of a digital city twin was proposed for the needs of urban planning, and future challenges were identified.

4D Bioprinting Shape‐Morphing Tissues in Granular Support Hydrogels: Sculpting Structure and Guiding Maturation

AbstractDuring embryogenesis, organs undergo dynamic shape transformations that sculpt their final shape, composition, and function. Despite this, current organ bioprinting approaches typically employ bioinks that restrict cell‐generated morphogenetic behaviors resulting in structurally static tissues. This work introduces a novel platform that enables the bioprinting of tissues that undergo programmable and predictable 4D shape‐morphing driven by cell‐generated forces. This method utilizes embedded bioprinting to deposit collagen‐hyaluronic acid bioinks within yield‐stress granular support hydrogels that can accommodate and regulate 4D shape‐morphing through their viscoelastic properties. Importantly, precise control over 4D shape‐morphing is possible by modulating factors such as the initial print geometry, cell phenotype, bioink composition, and support hydrogel viscoelasticity. Further, shape‐morphing is found to actively sculpt cell and extracellular matrix alignment along the principal tissue axis through a stress‐avoidance mechanism. To enable predictive design of 4D shape‐morphing patterns, a finite element model is developed that accurately captures shape evolution at both the cellular and tissue levels. Finally, it is demonstrated that programmed 4D shape‐morphing enhances the structural and functional properties of iPSC‐derived heart tissues. This ability to design, predict, and program 4D shape‐morphing holds great potential for engineering organ rudiments that recapitulate morphogenetic processes to sculpt their final shape, composition, and function.

Maintenance of a central high frequency synapse in the absence of synaptic activity.

Activity has long been considered essential for circuit formation and maintenance. This view has recently been challenged by proper synaptogenesis and only mildly affected synapse maintenance in the absence of synaptic activity in forebrain neurons. Here, we investigated whether synaptic activity is necessary for the development and maintenance of the calyx of Held synapse. This giant synapse located in the auditory brainstem is highly specialized to maintain high frequency, high-fidelity synaptic transmission for prolonged times and thus shows particularly high synaptic activity. We expressed the protease tetanus toxin light chain (TeNT) exclusively in bushy cells of the ventral cochlear nucleus (VCN) of juvenile mice. Since globular bushy cells give rise to the calyx of Held, expression of TeNT in these cells specifically abolished synaptic transmission at the calyx without impairing general functionality of the central auditory system. Calyces lacked synaptic activity after two weeks of TeNT expression. However, this did not lead to major changes in presynaptic morphology, the number of active zones (AZs) or the composition of postsynaptic AMPA-type glutamate receptors (GluAs). Moreover, the fenestration of the calyx of Held, a hallmark of structural maturation, occurred normally. We thus show that the maintenance of a specialized high frequency synapse in the auditory brainstem occurs in a hardwired, probably genetically encoded, manner with little dependence on synaptic activity.

Tertiary lymphoid structures potentially promote immune checkpoint inhibitor response in SMARCB1-deficient medullary renal cell carcinoma

The WHO’s classification of renal cell carcinoma (RCC) has identified loss of SMARCB1 as one of the driven mutations. Despite intensive postoperative interventions, the prognosis for SMARCB1-deficient medullary RCC remains poor, indicating insufficiency in current therapy. Herein, we reported the treatment outcomes of five patients with metastatic SMARCB1-deficient medullary RCC and molecular correlates. Four patients were treated with first-line immune checkpoint inhibitors (ICI) plus tyrosine kinase inhibitors (TKI) combination therapy with a median PFS (mPFS) of 12.3 months. Transcriptomic analysis revealed enrichment of immune-related pathways in SMARCB1-deficient medullary RCC compared to clear-cell and papillary RCC. Multiple immunofluorescence (mIF) revealed the association between the formation of mature tertiary lymphoid structures (TLSs) and the favorable response to ICI-based combination therapy. In conclusion, ICI-based combination therapy showed promising anti-tumor activity in SMARCB1-deficient medullary RCC patients. The presence of mature tertiary TLSs may partially elucidate the mechanism underlying treatment response.

Capital market liberalization and corporate debt maturity structure: evidence from the Shanghai-Shenzhen-Hong Kong Stock connect

PurposeThis paper takes the Shanghai-Shenzhen-Hong Kong Stock Connect as a quasi-natural experiment and investigates the impact of capital market liberalization on the corporate debt maturity structure. It also aims to provide some policy implications for corporate debt financing and further liberalization of the capital market in China.Design/methodology/approachEmploying the exogenous event of Shanghai-Shenzhen-Hong Kong Stock Connect and using the data of Chinese A-share firms from 2010 to 2020, this study constructs a difference-in-differences model to examine the relationship between capital market liberalization and corporate debt maturity structure. To validate the results, this study performed several robustness tests, including the parallel test, the placebo test, the Heckman two-stage regression and the propensity score matching.FindingsThis paper finds that capital market liberalization has significantly increased the proportion of long-term debt of target firms. Further analyses suggest that the impact of capital market liberalization on the debt maturity structure is more pronounced for firms with lower management ownership and non-Big 4 audit. Channel tests show that capital market liberalization improves firms’ information environment and curbs self-interested management behavior.Originality/valueThis research provides empirical evidence for the consequences of capital market liberalization and enriches the literature on the determinants of corporate debt maturity structure. Further this study makes a reference for regulators and financial institutions to improve corporate financing through the governance role of capital market liberalization.

2'-Fucosyllactose and 3'-Sialyllactose Reduce Mortality in Neonatal Enteroaggregative Escherichia coli Infection by Improving the Construction of Intestinal Mucosal Immunity.

Human milk oligosaccharides could prevent pathogenic bacterial infections in neonates; however, direct in vivo anti-infection evidence was still lacking. Here, we systematically evaluated the effects of 2'-fucosyllactose (2'-FL) and 3'-sialyllactose (3'-SL) on the structural development and functional maturation in neonates and their defense against enteroaggregative Escherichia coli infection. It was found that supplementation with 2'-FL and 3'-SL improved the resistance of weaned mice to enteroaggregative E. coli. The mechanism related to the promotion of 2'-FL and 3'-SL in the maturation of intestinal mucosal immunity by promoting stem cell differentiation, mucus layer integrity, and tight junction formation. 2'-FL and 3'-SL significantly increased the ratio of Th1 and Treg cells in the lamina propria, contents of short-chain fatty acids, as well as the serum content of IgA. This study lays a theoretical basis for the application of 2'-FL and 3'-SL in infant formula, as well as the development of intestinal health products.

Carbon assurance, corporate capital structure, and debt maturity: Global evidence

This study used a cross-country sample of firms from 47 nations that participated in the Carbon Disclosure Project (CDP) questionnaire over the years 2011 and 2020, to examine whether the verification of carbon emissions information by an independent third party affects corporate capital structure and debt maturity decisions. Using alternative methods and robustness checks, we explore that carbon assurance importantly shapes both corporate capital structure and debt maturity. In particular, firms that are involved in independent carbon assurance have significantly higher leverage in their capital structure compared to non-assured firms. Further, assured firms have better access to long-term debt compared to non-assured firms. The outcomes of this study are attributed to the notion that the verification of carbon information increases the creditability of a firm's voluntary reporting and reduces its informational asymmetry between corporations and lenders.

Imaging Mass Cytometry to Decipher the Maturation of Tertiary Lymphoid Structures.

In the realm of inflammation, including conditions like cancers, infections, and autoimmune diseases, the emergence of tertiary lymphoid structures (TLS) holds significant implications for prognosis and treatment response. Yet, traditional methodologies such as immunohistochemistry and immunofluorescence falter in capturing the nuanced complexities of TLS, necessitating innovative approaches, like imaging mass cytometry (IMC), to unravel their significance. With the capacity to concurrently assess nearly 40 markers within the same tissue section, IMC transcends the constraints of traditional approaches.This chapter delineates the IMC methodology tailored for TLS visualization and subsequent quantification. By leveraging IMC on formalin-fixed, paraffin-embedded (FFPE) sections of human colorectal cancer (CRC) tissues, we aim to establish a standardized protocol that elucidates the intricacies of TLS dynamics and composition.

Maturation of Tertiary Lymphoid Structures.

Tertiary lymphoid structures (TLS) are organized collections of B and T lymphocytes that arise in nonlymphoid tissue in response to chronic, unresolved inflammation. TLS have structural and functional similarities to germinal centers found in lymph nodes and are believed to support the establishment of lymph node-like adaptive immune responses at local sites of inflammation. However, understanding of the underlying biology of these structures remains limited, particularly the different stages of TLS life cycle and the signals governing the initiation, maturation, and termination of TLS. Here, we review current understanding of the maturation of TLS and the signals and cell types involved in various stages of development with particular emphasis on recent studies of TLS in cancer, where evidence suggests that TLS may play an important role in supporting antitumor immune responses in solid tumors.

Oncolytic immunotherapy with nivolumab in muscle-invasive bladder cancer: a phase 1b trial.

There is a critical unmet need for safe and efficacious neoadjuvant treatment for cisplatin-ineligible patients with muscle-invasive bladder cancer. Here we launched a phase 1b study using the combination of intravesical cretostimogene grenadenorepvec (oncolytic serotype 5 adenovirus encoding granulocyte-macrophage colony-stimulating factor) with systemic nivolumab in cisplatin-ineligible patients with cT2-4aN0-1M0 muscle-invasive bladder cancer. The primary objective was to measure safety, and the secondary objective was to assess the anti-tumor efficacy as measured by pathologic complete response along with 1-year recurrence-free survival. No dose-limiting toxicity was encountered in 21 patients enrolled and treated. Combination treatment achieved a pathologic complete response rate of 42.1% and a 1-year recurrence-free survival rate of 70.4%. Pathologic response was associated with baseline free E2F activity and tumor mutational burden but not PD-L1 status. Although T cell infiltration was broadly induced after intravesical oncolytic immunotherapy, the formation, enlargement and maturation of tertiary lymphoid structures was specifically associated with complete response, supporting the importance of coordinated humoral and cellular immune responses. Together, these results highlight the potential of this combination regimen to enhance therapeutic efficacy in cisplatin-ineligible patients with muscle-invasive bladder cancer, warranting additional study as a neoadjuvant therapeutic option. ClinicalTrials.gov identifier: NCT04610671 .

Induced pluripotent stem cell-derived cardiomyocyte in vitro models: benchmarking progress and ongoing challenges.

Recent innovations in differentiating cardiomyocytes from human induced pluripotent stem cells (hiPSCs) have unlocked a viable path to creating in vitro cardiac models. Currently, hiPSC-derived cardiomyocytes (hiPSC-CMs) remain immature, leading many in the field to explore approaches to enhance cell and tissue maturation. Here, we systematically analyzed 300 studies using hiPSC-CM models to determine common fabrication, maturation and assessment techniques used to evaluate cardiomyocyte functionality and maturity and compiled the data into an open-access database. Based on this analysis, we present the diversity of, and current trends in, in vitro models and highlight the most common and promising practices for functional assessments. We further analyzed outputs spanning structural maturity, contractile function, electrophysiology and gene expression and note field-wide improvements over time. Finally, we discuss opportunities to collectively pursue the shared goal of hiPSC-CM model development, maturation and assessment that we believe are critical for engineering mature cardiac tissue.

The conserved HIV-1 spacer peptide 2 triggers matrix lattice maturation.

HIV-1 particles are released in an immature, non-infectious form. Proteolytic cleavage of the main structural polyprotein Gag into functional domains induces rearrangement into mature, infectious virions. In immature virus particles, the Gag membrane binding domain, MA, forms a hexameric protein lattice that undergoes structural transition upon cleavage into a distinct, mature MA lattice. The mechanism of MA lattice maturation is unknown. Here we show that released spacer peptide 2 (SP2), a conserved peptide of unknown function situated ∼300 residues downstream of MA, binds MA to induce structural maturation. By high-resolution in-virus structure determination of MA, we show that MA does not bind lipid into a side pocket as previously thought, but instead binds SP2 as an integral part of the protein-protein interfaces that stabilise the mature lattice. Analysis of Gag cleavage site mutants showed that SP2 release is required for MA maturation, and we demonstrate that SP2 is sufficient to induce maturation of purified MA on lipid layers in vitro. SP2-triggered MA maturation correlated with faster fusion of virus with target cells. Our results reveal a new, unexpected interaction between two HIV-1 components, provide a high-resolution structure of mature MA, establish the trigger of MA structural maturation, and assign function to the SP2 peptide.

ER Oxidoreductin 1-Like Activity of Cyclic Diselenides Drives Protein Disulfide Isomerase in an Electron Relay System.

Disulfide formation generally involves a two-electron oxidation reaction between cysteine residues. Additionally, disulfide formation is an essential post-translational modification for the structural maturation of proteins. This oxidative folding is precisely controlled by an electron relay network constructed by protein disulfide isomerase (PDI), with a CGHC sequence as the redox-active site, and its family enzymes. Creating reagents that mimic the functions of these enzymes facilitates folding during chemical protein synthesis. In this study, we aimed to imitate a biological electron relay system using cyclic diselenide compounds as surrogates for endoplasmic reticulum oxidoreductin 1 (Ero1), which is responsible for the re-oxidation of PDI. Oxidized PDI (PDIox) introduces disulfide bonds into substrate proteins, resulting in its conversion to reduced PDI (PDIred). The PDIred is then re-oxidized to PDIox by a coexisting cyclic diselenide compound, thereby restoring the function of PDI as a disulfide-forming agent. The produced diselenol state is readily oxidized to the original diselenide state with molecular oxygen, continuously sustaining the PDI catalytic cycle. This artificial electron relay system regulating enzymatic PDI function effectively promotes the oxidative folding of disulfide-containing proteins, such as insulin-a hypoglycemic formulation-by enhancing both yield and reaction velocity.

Identification and synthesis of a long-chain antimicrobial peptide from the venom of the Liocheles australasiae scorpion.

Scorpion venom contains linear peptides without disulfide bonds in addition to peptides with disulfide bonds. Many such linear peptides have an amphiphilic α-helical structure, often with antimicrobial activity and can be classified into three groups based on their molecular size. Among them, long-chain antimicrobial peptides consisting of more than 40 residues have not been thoroughly studied due to the difficulty of synthesizing them. We have previously reported a transcriptome analysis of the venom gland of Liocheles australasiae that revealed precursor sequences of long-chain antimicrobial peptides. In the study reported here, we identified the mature structure of one such long-chain antimicrobial peptide, LaCT1, which we synthesized using chemical ligation to confirm its structure and evaluate its biological activities. The result showed that LaCT1 exhibited significant antimicrobial activity. In addition, we identified its partial peptides consisting of an N- or C-terminal region, which may be generated by enzymatic cleavage in the venom. Among them, only the peptide containing the N-terminal half region was active. LaCT1 also not only showed insecticidal activity but also synergistically enhanced the effects of another insecticidal peptide identified in L. australasiae venom as well. These results provide insights into the role of antimicrobial peptides in scorpion venom.

CLSTN3B promotes lipid droplet maturation and lipid storage in mouse adipocytes

Interorganelle contacts facilitate material exchanges and sustain the structural and functional integrity of organelles. Lipid droplets (LDs) of adipocytes are responsible for energy storage and mobilization responding to body needs. LD biogenesis defects compromise the lipid-storing capacity of adipocytes, resulting in ectopic lipid deposition and metabolic disorders, yet how the uniquely large LDs in adipocytes attain structural and functional maturation is incompletely understood. Here we show that the mammalian adipocyte-specific protein CLSTN3B is crucial for adipocyte LD maturation. CLSTN3B employs an arginine-rich segment to promote extensive contact and hemifusion-like structure formation between the endoplasmic reticulum (ER) and LD, allowing ER-to-LD phospholipid diffusion during LD expansion. CLSTN3B ablation results in reduced LD surface phospholipid density, increased turnover of LD-surface proteins, and impaired LD functions. Our results establish the central role of CLSTN3B in the adipocyte-specific LD maturation pathway that enhances lipid storage and maintenance of metabolic health under caloric overload in mice of both sexes.