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1.
Adv Healthc Mater ; : e2401260, 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38953344

RESUMO

Polyetheretherketone (PEEK), a bioinert polymer known for its mechanical properties similar to bone, is capable of averting stress shielding. Due to these attributes, it finds applications in diverse fields like orthopedics, encompassing cervical disc replacement for the neck and spine, along with dentistry and plastic surgery. However, due to insufficient bonding with bone, various methods such as hydroxyapatite (HA) coating on the surface are attempted. Nonetheless, the interface between the polymer and ceramic, two different materials, tended to delaminate after transplantation, posing challenges in preventing implant escape or dislodgement. This research delves into the laser-driven hydroxyapatite penetration-synthesis technique. Differing from conventional coating methods that bond layers of dissimilar materials like HA and PEEK, this technology focuses on synthesizing and infiltrating ionized HA within the PEEK substrate resulting in an interface-free HA-PEEK surface. Conversely, HA-PEEK with this technology applied achieves complete, gap-free direct bone-implant integration.  Our research involved the analysis of various aspects. By means of these, we quantitatively assesed the enhanced bone bonding characteristics of HA-PEEK surfaces treated with this approach and offered and explanation for the mechanism responsible for direct bone integration.

2.
Opt Lett ; 49(13): 3830-3833, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38950279

RESUMO

We developed analytical expressions for the Wigner distribution function of partially coherent fields generated by the scattering of beams with a particular phase structure, namely perfect optical vortex beams. In addition, we provide the modal decomposition of the field correlations and evaluate the evolution of Shannon entropy associated with the partially coherent field.

3.
Ann Surg Treat Res ; 106(6): 330-336, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38868581

RESUMO

Purpose: Managing recurrent inguinal hernias is complex, and choosing the right surgical approach (laparoscopic vs. open) is vital for patient outcomes. This study compared the outcomes of using the same vs. different surgical approaches for initial and subsequent hernia repairs. Methods: We retrospectively analyzed patients who underwent recurrent inguinal hernia repair at Seoul National University Bundang Hospital between January 2014 and May 2023. Patients were divided into the "concordant" and "discordant" groups, comprising patients who underwent same and different approaches in both surgeries, respectively. Preoperative baseline characteristics, index surgery data, postoperative outcomes, and recurrence rates were analyzed and compared. Results: In total, 131 patients were enrolled; the concordant and discordant groups comprised 31 (open, n = 19; laparoscopic, n = 12) and 100 patients (open to laparoscopic, n = 68; laparoscopic to open, n = 32), respectively. No significant differences were observed in the mean operation time (50.5 ± 21.7 minutes vs. 50.2 ± 20.0 minutes, P = 0.979), complication rates (6.5% vs. 14.0%, P = 0.356), or 36-month cumulative recurrence rates (9.8% vs. 9.8%; P = 0.865). The mean postoperative hospital stay was significantly shorter in the discordant than in the concordant group (1.8 ± 0.7 vs. 1.4 ± 0.6, P = 0.003). Conclusion: Most recurrent inguinal hernia repairs were performed using the discordant surgical approach. Overall, concordance in the surgical approach did not significantly affect postoperative outcomes. Therefore, the selection of the surgical approach based on the patient's condition and surgeon's preference may be advisable.

4.
Dev Sci ; : e13540, 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38898660

RESUMO

Three preregistered studies examined whether 5-year-old children cheat consistently or remain honest across multiple math tests. We observed high consistency in both honesty and cheating. All children who cheated on the first test continued cheating on subsequent tests, with shorter cheating latencies over time. In contrast, 77% of initially honest children maintained honesty despite repeated failure to complete the tests successfully. A brief integrity intervention helped initially honest children remain honest but failed to dissuade initially cheating children from cheating. These findings demonstrate that cheating emerges early and persists strongly in young children, underscoring the importance of early prevention efforts. They also suggest that bolstering honesty from the start may be more effective than attempting to remedy cheating after it has occurred. RESEARCH HIGHLIGHTS: Our research examines whether 5-year-old children, once they have started cheating, will continue to do so consistently. We also investigate whether 5-year-old children who are initially honest will continue to be honest subsequently. We discovered high consistency in both honesty and cheating among 5-year-old children. Almost all the children who initially cheated continued this behavior, while those who were honest stayed honest. A brief integrity-boosting intervention successfully helped 5-year-old children maintain their honesty. However, the same intervention failed to deter cheaters from cheating again. These findings underscore the importance of implementing integrity intervention as early as possible, potentially before children have had their first experience of cheating.

6.
Bull Chem Soc Jpn ; 97(5): uoae018, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38828441

RESUMO

Due to their constrained conformations, cyclic ß2,3-amino acids (cßAA) are key building blocks that can fold peptides into compact and rigid structures, improving peptidase resistance and binding affinity to target proteins, due to their constrained conformations. Although the translation efficiency of cßAAs is generally low, our engineered tRNA, referred to as tRNAPro1E2, enabled efficient incorporation of cßAAs into peptide libraries using the flexible in vitro translation (FIT) system. Here we report on the design and application of a macrocyclic peptide library incorporating 3 kinds of cßAAs: (1R,2S)-2-aminocyclopentane carboxylic acid (ß1), (1S,2S)-2-aminocyclohexane carboxylic acid (ß2), and (1R,2R)-2-aminocyclopentane carboxylic acid. This library was applied to an in vitro selection against the SARS-CoV-2 main protease (Mpro). The resultant peptides, BM3 and BM7, bearing one ß2 and two ß1, exhibited potent inhibitory activities with IC50 values of 40 and 20 nM, respectively. BM3 and BM7 also showed remarkable serum stability with half-lives of 48 and >168 h, respectively. Notably, BM3A and BM7A, wherein the cßAAs were substituted with alanine, lost their inhibitory activities against Mpro and displayed substantially shorter serum half-lives. This observation underscores the significant contribution of cßAA to the activity and stability of peptides. Overall, our results highlight the potential of cßAA in generating potent and highly stable macrocyclic peptides with drug-like properties.

7.
Cell Metab ; 36(6): 1302-1319.e12, 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38838642

RESUMO

Glucagon-like peptide-1 receptor (GLP-1R) is a key regulator of glucose metabolism known to be expressed by pancreatic ß cells. We herein investigated the role of GLP-1R on T lymphocytes during immune response. Our data showed that a subset of T lymphocytes expresses GLP-1R, which is upregulated during alloimmune response, similarly to PD-1. When mice received islet or cardiac allotransplantation, an expansion of GLP-1Rpos T cells occurred in the spleen and was found to infiltrate the graft. Additional single-cell RNA sequencing (scRNA-seq) analysis conducted on GLP-1Rpos and GLP-1Rneg CD3+ T cells unveiled the existence of molecular and functional dissimilarities between both subpopulations, as the GLP-1Rpos are mainly composed of exhausted CD8 T cells. GLP-1R acts as a T cell-negative costimulatory molecule, and GLP-1R signaling prolongs allograft survival, mitigates alloimmune response, and reduces T lymphocyte graft infiltration. Notably, GLP-1R antagonism triggered anti-tumor immunity when tested in a preclinical mouse model of colorectal cancer.


Assuntos
Receptor do Peptídeo Semelhante ao Glucagon 1 , Transplante das Ilhotas Pancreáticas , Camundongos Endogâmicos C57BL , Animais , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Camundongos , Linfócitos T/imunologia , Linfócitos T/metabolismo , Masculino , Transplante de Coração , Camundongos Endogâmicos BALB C , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/imunologia , Sobrevivência de Enxerto/imunologia
8.
Molecules ; 29(12)2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38930994

RESUMO

The tetradentate ligand, merging a carbazole unit with high triplet energy and dimethoxy bipyridine, renowned for its exceptional quantum efficiency in coordination with metals like Pt, is expected to demonstrate remarkable luminescent properties. However, instances of tetradentate ligands such as bipyridine-based pyridylcarbazole derivatives remain exceptionally scarce in the current literature. In this study, we developed a tetradentate ligand based on carbazole and 2,3'-bipyridine and successfully complexed it with Pt(II) ions. This novel compound (1) serves as a sky-blue phosphorescent material for use in light-emitting diodes. Based on single-crystal X-ray analysis, compound 1 has a distorted square-planar geometry with a 5/6/6 backbone around the Pt(II) core. Bright sky-blue emissions were observed at 488 and 516 nm with photoluminescent quantum yields of 34% and a luminescent lifetime of 2.6 µs. TD-DFT calculations for 1 revealed that the electronic transition was mostly attributed to the ligand-centered (LC) charge transfer transition with a small contribution from the metal-to-ligand charge transfer transition (MLCT, ~14%). A phosphorescent organic light-emitting device was successfully fabricated using this material as a dopant, along with 3'-di(9H-carbazol-9-yl)-1,1'-biphenyl (mCBP) and 9-(3'-carbazol-9-yl-5-cyano-biphenyl-3-yl)-9H-carbazole-3-carbonitrile (CNmCBPCN) as mixed hosts. A maximum quantum efficiency of 5.2% and a current efficiency of 15.5 cd/A were obtained at a doping level of 5%.

9.
J Hazard Mater ; 475: 134939, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38889466

RESUMO

Dense non-aqueous-phase liquids (DNAPLs) represent one of the most hazardous contaminants of groundwater, posing health risks to humans. Radon is generally used to trace DNAPLs; however, external factors, such as rainfall or stream water, can influence its efficacy. To overcome these limitations, this study pioneered the integration of radon and microbial community structures to explore DNAPL tracing and natural attenuation in the context of seasonal variations for human health risk assessments. The results showed that a radon tracer can estimate DNAPL saturation in the source zone, especially during the dry season when radon deficiency predominates. However, samples exhibited mixing effects during the wet season because of local precipitation. Moreover, bioremediation and low health risks were observed in the plume boundary zone, indicating that microbial dechlorination was a predominant factor determining these risks. The abnormal patterns of radon observed during the wet season can be elucidated by examining microbiological communities. Consequently, a combined approach employing radon and microbial analysis is advocated for the boundary zone, albeit with a less intensive management strategy, compared with that for the source zone. This novel coupling method offers a theoretical and practical foundation for managing DNAPL-contaminated groundwater.


Assuntos
Água Subterrânea , Radônio , Estações do Ano , Poluentes Radioativos da Água , Água Subterrânea/microbiologia , Água Subterrânea/química , Radônio/análise , Medição de Risco , Poluentes Radioativos da Água/análise , Microbiologia da Água , Humanos , Biodegradação Ambiental
10.
Yonsei Med J ; 65(7): 380-388, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38910300

RESUMO

PURPOSE: Although advancements in medical treatments have been made, approximately half of patients with intestinal Crohn's disease (CD) require intestinal resections during their lifetime. It is well-known that the nutritional status of CD patients can impact postoperative morbidity. The objective of this study was to evaluate the clinical significance of prognostic nutritional index (PNI) in patients with intestinal CD who underwent primary bowel resection. MATERIALS AND METHODS: We retrospectively investigated patients who were diagnosed with CD and underwent intestinal surgery at Severance Hospital between January 2005 and October 2018. The patients were divided into two groups: PNI ≤40 (n=150) and PNI >40 (n=77). We assessed the clinical significance of PNI in terms of the incidence of postoperative infectious complications (PICs) and the postoperative recurrence of CD. RESULTS: The low PNI group had significantly higher rates of infectious complications (32.0% vs. 10.4%, p=0.001) compared to the high PNI group. Multivariable analysis identified low PNI (≤40) and longer operation time (>180 min) as independent risk factors associated with PICs [odds ratio (OR)=2.754, 95% confidence interval (CI)=1.140-6.649, p=0.024; OR=2.986, 95% CI=1.451-6.143, p=0.003]. PICs were significantly associated with surgical recurrence (hazard ratio=2.217, 95% CI=1.064-4.617, p=0.034). CONCLUSION: Preoperative PNI could serve as a predictive factor for PICs in CD patients who undergo intestinal resection. Additionally, PICs are significantly associated with a higher risk of surgical recurrence in CD.


Assuntos
Doença de Crohn , Avaliação Nutricional , Complicações Pós-Operatórias , Humanos , Doença de Crohn/cirurgia , Feminino , Masculino , Adulto , Estudos Retrospectivos , Prognóstico , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Pessoa de Meia-Idade , Estado Nutricional , Fatores de Risco , Adulto Jovem , Recidiva , Relevância Clínica
11.
Bioengineering (Basel) ; 11(6)2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38927804

RESUMO

Ultra-widefield (UWF) retinal imaging stands as a pivotal modality for detecting major eye diseases such as diabetic retinopathy and retinal detachment. However, UWF exhibits a well-documented limitation in terms of low resolution and artifacts in the macular area, thereby constraining its clinical diagnostic accuracy, particularly for macular diseases like age-related macular degeneration. Conventional supervised super-resolution techniques aim to address this limitation by enhancing the resolution of the macular region through the utilization of meticulously paired and aligned fundus image ground truths. However, obtaining such refined paired ground truths is a formidable challenge. To tackle this issue, we propose an unpaired, degradation-aware, super-resolution technique for enhancing UWF retinal images. Our approach leverages recent advancements in deep learning: specifically, by employing generative adversarial networks and attention mechanisms. Notably, our method excels at enhancing and super-resolving UWF images without relying on paired, clean ground truths. Through extensive experimentation and evaluation, we demonstrate that our approach not only produces visually pleasing results but also establishes state-of-the-art performance in enhancing and super-resolving UWF retinal images. We anticipate that our method will contribute to improving the accuracy of clinical assessments and treatments, ultimately leading to better patient outcomes.

12.
Bioengineering (Basel) ; 11(6)2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38927806

RESUMO

The aim of this study was to assess the usefulness of an attachable video laryngoscope (AVL) by attaching a camera and a monitor to a conventional Macintosh laryngoscope (CML). Normal and tongue edema airway scenarios were simulated using a manikin. Twenty physicians performed tracheal intubations using CML, AVL, Pentax Airwayscope® (AWS), and McGrath MAC® (MAC) in each scenario. Ten physicians who had clinical experience in using tracheal intubation were designated as the skilled group, and another ten physicians who were affiliated with other departments and had little clinical experience using tracheal intubation were designated as the unskilled group. The time required for intubation and the success rate were recorded. The degree of difficulty of use and glottic view assessment were scored by participants. All 20 participants successfully completed the study. There was no difference in tracheal intubation success rate and intubation time in the normal airway scenario in both skilled and unskilled groups. In the experienced group, AWS had the highest success rate (100%) in the tongue edema airway scenario, followed by AVL (60%), MAC (60%), and CML (10%) (p = 0.001). The time required to intubate using AWS was significantly shorter than that with AVL (10.2 s vs. 19.2 s) or MAC (10.2 s vs. 20.4 s, p = 0.007). The difficulty of using AVL was significantly lower than that of CML (7.8 vs. 2.8; p < 0.001). For the experienced group, AVL was interpreted as being inferior to AWS but better than MAC. Similarly, in the unskilled group, AVL had a similar success rate and tracheal intubation time as MAC in the tongue edema scenario, but this was not statistically significant. The difficulty of using AVL was significantly lower than that of CML (8.8 vs. 3.3; p < 0.001). AVL may be an alternative for VL.

13.
Clin Orthop Surg ; 16(3): 397-404, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38827762

RESUMO

Background: The objective of this study was to investigate the incidence of osteonecrosis of the femoral head (ONFH) after cephalomedullary nailing in elderly patients with pertrochanteric fractures and to analyze the risk factors related to ONFH. Methods: A total of 689 consecutive patients with cephalomedullary nailing for pertrochanteric fractures at our hospital were recruited. Of these, 368 patients who met the inclusion criteria were finally enrolled. ONFH after cephalomedullary nailing was identified by reviewing patients' electronic charts and serial radiographs. The ONFH group was then compared with the non-ONFH group. Results: ONFH was identified in 9 of 368 patients (2.4%). The time to diagnosis of ONFH averaged 23.8 months (range, 5-54 months) after index surgery. The mean age, body mass index, and bone mineral density (T-score in femur neck) were 84.1 ± 7.1 years, 23.7 ± 3.6 kg/m2, and -3.1 ± 0.7 kg/m2, respectively. The times from injury to surgery, from admission to surgery, and operation time averaged 4.2 ± 2.7 days, 3.6 ± 2.6 days, and 87.2 ± 30.0 minutes, respectively. Among 9 patients, 3 underwent conversion arthroplasty. The ONFH group had advanced age (p = 0.029), more basicervical fracture components (p = 0.002), and inadequate reduction (p = 0.045) compared to the non-ONFH group. On multivariate analysis, advanced age (odds ratio [OR], 1.61;, p = 0.022), basicervical fracture components (OR, 24.58; p = 0.001), and inadequate reduction (OR, 4.11; p = 0.039) were identified as risk factors of ONFH. Conclusions: Although ONFH is relatively rare after cephalomedullary nailing for pertrochanteric fractures in elderly patients, its risk may increase with advanced age, basicervical fracture components, and inadequate reduction. Therefore, in patients with these risk factors, meticulous and longer follow-up is needed even after bone union.


Assuntos
Necrose da Cabeça do Fêmur , Fixação Intramedular de Fraturas , Fraturas do Quadril , Humanos , Masculino , Feminino , Fatores de Risco , Idoso , Idoso de 80 Anos ou mais , Fraturas do Quadril/cirurgia , Fixação Intramedular de Fraturas/efeitos adversos , Fixação Intramedular de Fraturas/métodos , Incidência , Necrose da Cabeça do Fêmur/cirurgia , Necrose da Cabeça do Fêmur/etiologia , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Pinos Ortopédicos , Estudos Retrospectivos
14.
bioRxiv ; 2024 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-38826421

RESUMO

Monogenic syndromes are associated with neurodevelopmental changes that result in cognitive impairments, neurobehavioral phenotypes including autism and attention deficit hyperactivity disorder (ADHD), and seizures. Limited studies and resources are available to make meaningful headway into the underlying molecular mechanisms that result in these symptoms. One such example is DeSanto-Shinawi Syndrome (DESSH), a rare disorder caused by pathogenic variants in the WAC gene. Individuals with DESSH syndrome exhibit a recognizable craniofacial gestalt, developmental delay/intellectual disability, neurobehavioral symptoms that include autism, ADHD, behavioral difficulties and seizures. However, no thorough studies from a vertebrate model exist to understand how these changes occur. To overcome this, we developed both murine and zebrafish Wac/wac deletion mutants and studied whether their phenotypes recapitulate those described in individuals with DESSH syndrome. We show that the two Wac models exhibit craniofacial and behavioral changes, reminiscent of abnormalities found in DESSH syndrome. In addition, each model revealed impacts to GABAergic neurons and further studies showed that the mouse mutants are susceptible to seizures, changes in brain volumes that are different between sexes and relevant behaviors. Finally, we uncovered transcriptional impacts of Wac loss of function that will pave the way for future molecular studies into DESSH. These studies begin to uncover some biological underpinnings of DESSH syndrome and elucidate the biology of Wac, with advantages in each model.

15.
Br J Pharmacol ; 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38925168

RESUMO

BACKGROUND AND PURPOSE: Mitochondrial dysfunction contributes to the pathogenesis and maintenance of chemotherapy-induced peripheral neuropathy (CIPN), a significant limitation of cancer chemotherapy. Recently, the stimulation of mitophagy, a pivotal process for mitochondrial homeostasis, has emerged as a promising treatment strategy for neurodegenerative diseases, but its therapeutic effect on CIPN has not been explored. Here, we assessed the mitophagy-inducing activity of 3,5-dibromo-2-(2',4'-dibromophenoxy)-phenol (PDE701), a diphenyl ether derivative isolated from the marine sponge Dysidea sp., and investigated its therapeutic effect on a CIPN model. EXPERIMENTAL APPROACH: Mitophagy activity was determined by a previously established mitophagy assay using mitochondrial Keima (mt-Keima). Mitophagy induction was further verified by western blotting, immunofluorescence, and electron microscopy. Mitochondrial dysfunction was analysed by measuring mitochondrial superoxide levels in SH-SY5Y cells and Drosophila larvae. A thermal nociception assay was used to evaluate the therapeutic effect of PDE701 on the paclitaxel-induced thermal hyperalgesia phenotype in Drosophila larvae. KEY RESULTS: PDE701 specifically induced mitophagy but was not toxic to mitochondria. PDE701 ameliorated paclitaxel-induced mitochondrial dysfunction in both SH-SY5Y cells and Drosophila larvae. Importantly, PDE701 also significantly ameliorated paclitaxel-induced thermal hyperalgesia in Drosophila larvae. Knockdown of ATG5 or ATG7 abolished the effect of PDE701 on thermal hyperalgesia, suggesting that PDE701 exerts its therapeutic effect through mitophagy induction. CONCLUSION AND IMPLICATIONS: This study identified PDE701 as a novel mitophagy inducer and a potential therapeutic compound for CIPN. Our results suggest that mitophagy stimulation is a promising strategy for the treatment of CIPN and that marine organisms are a potential source of mitophagy-inducing compounds.

16.
J Am Chem Soc ; 146(26): 17691-17699, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38888290

RESUMO

Nonproteinogenic amino acids, including d-α-, ß-, and γ-amino acids, present in bioactive peptides play pivotal roles in their biochemical activities and proteolytic stabilities. d-α-Amino acids (dαAA) are widely used building blocks that can enhance the proteolytic stability. Cyclic ß2,3-amino acids (cßAA), for instance, can fold peptides into rigid secondary structures, improving the binding affinity and proteolytic stability. Cyclic γ2,4-amino acids (cγAA) are recently highlighted as rigid residues capable of preventing the proteolysis of flanking residues. Simultaneous incorporation of all dαAA, cßAA, and cγAA into a peptide is expected to yield l-α/d-α/ß/γ-hybrid peptides with improved stability and potency. Despite challenges in the ribosomal incorporation of multiple nonproteinogenic amino acids, our engineered tRNAPro1E2 successfully reaches such a difficulty. Here, we report the ribosomal synthesis of macrocyclic l-α/d-α/ß/γ-hybrid peptide libraries and their application to in vitro selection against interferon gamma receptor 1 (IFNGR1). One of the resulting l-α/d-α/ß/γ-hybrid peptides, IB1, exhibited remarkable inhibitory activity against the IFN-γ/IFNGR1 protein-protein interaction (PPI) (IC50 = 12 nM), primarily attributed to the presence of a cßAA in the sequence. Additionally, cγAAs and dαAAs in the resulting peptides contributed to their serum stability. Furthermore, our peptides effectively inhibit IFN-γ/IFNGR1 PPI at the cellular level (best IC50 = 0.75 µM). Altogether, our platform expands the chemical space available for exploring peptides with high activity and stability, thereby enhancing their potential for drug discovery.


Assuntos
Receptor de Interferon gama , Interferon gama , Receptores de Interferon , Interferon gama/metabolismo , Receptores de Interferon/metabolismo , Receptores de Interferon/química , Humanos , Ligação Proteica , Compostos Macrocíclicos/química , Compostos Macrocíclicos/farmacologia , Peptídeos/química , Peptídeos/farmacologia , Peptídeos Cíclicos/química , Peptídeos Cíclicos/farmacologia , Peptídeos Cíclicos/metabolismo
17.
Small ; : e2401989, 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38855993

RESUMO

The minimally invasive deployment of scaffolds is a key safety factor for the regeneration of cartilage and bone defects. Osteogenesis relies primarily on cell-matrix interactions, whereas chondrogenesis relies on cell-cell aggregation. Bone matrix expansion requires osteoconductive scaffold degradation. However, chondrogenic cell aggregation is promoted on the repellent scaffold surface, and minimal scaffold degradation supports the avascular nature of cartilage regeneration. Here, a material satisfying these requirements for osteochondral regeneration is developed by integrating osteoconductive hydroxyapatite (HAp) with a chondroconductive shape memory polymer (SMP). The shape memory function-derived fixity and recovery of the scaffold enabled minimally invasive deployment and expansion to fill irregular defects. The crystalline phases on the SMP surface inhibited cell aggregation by suppressing water penetration and subsequent protein adsorption. However, HAp conjugation SMP (H-SMP) enhanced surface roughness and consequent cell-matrix interactions by limiting cell aggregation using crystal peaks. After mouse subcutaneous implantation, hydrolytic H-SMP accelerated scaffold degradation compared to that by the minimal degradation observed for SMP alone for two months. H-SMP and SMP are found to promote osteogenesis and chondrogenesis, respectively, in vitro and in vivo, including the regeneration of rat osteochondral defects using the binary scaffold form, suggesting that this material is promising for osteochondral regeneration.

20.
Dalton Trans ; 53(24): 10120-10125, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38817194

RESUMO

Nickel monocarbonyl species with Ni(I) and Ni(0) have been synthesized and fully characterized by employing an acriPNP-Ph pincer ligand having a -C(Ph)2- bridge moiety to tether two aromatic rings. To see the effect of the bridge moiety, these complexes were structurally compared with the previously studied nickel complexes supported by PNP and acriPNP-Me ligands and methylation of the nickel carbonyl species was particularly investigated. Since a Ni(I)-CO species is known to be one of the key intermediates during the C-C coupling reaction to give an acetyl species, according to the paramagnetic mechanism of acetyl coenzyme A synthase (ACS), their reactivity toward MeI has been examined. Methylation of a nickel(I)-CO species reveals enhanced C-C coupling when both acriPNP-Me and acriPNP-Ph ligands were used. According to spin density analysis calculated by density functional theory, all Ni(I)-CO species reveal similar spin density at nickel and the carbon atom of CO. X-ray crystallographic data suggest that the corresponding selectivity may be related to the steric influence. For both (acriPNP-Ph)Ni-CO (2) and (acriPNP-Me)Ni-CO (2'), the nickel(I) site is sterically well protected, leading to selective interaction with a methyl radical to give a nickel acyl product. Steric influence was marginally observed when an anionic {(acriPNP-R)Ni-CO}- (R = Me or Ph) species reacted with MeI. The corresponding C-C coupled product was also observed from the methylation of nickel(0)-CO species.

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