RESUMEN

This research investigates the effects of various curing regimes, the incorporation of titanium slag, and the utilization of quartz sand on the strength properties and shrinkage behavior of ultra-high-performance concrete (UHPC). By using low-heat silicate cement to prepare UHPC, this study conducted standard curing and steam curing, and comprehensively analyzed the macro and micro performance of UHPC under different curing conditions. The findings indicate that the application of steam curing markedly enhances the mechanical attributes of UHPC while efficiently decreasing its drying shrinkage. In the comparative tests, we found that the compressive strength of concrete that had undergone 2 days of steam curing was 9.15% higher than that of concrete cured for 28 days under standard conditions. In addition, under the same curing conditions, titanium slag sand had higher mechanical properties than quartz sand. Under standard curing conditions, the 28-day compressive strength of UHPC using titaniferous slag aggregate was 12.64% higher than that of UHPC using standard sand. Through the data analysis of XRD, TG, and MIP, we found that the content of Ca(OH)2 in the hydration products after steam curing was reduced compared to the standard curing conditions, and the pore structure had been optimized. The UHPC prepared with titanium slag sand has greater advantages in mechanical properties and drying shrinkage, and has a smaller pore structure than the UHPC prepared with quartz sand. Moreover, the use of titanium slag sand offers ecological and economic benefits, making it a more sustainable and cost-effective option for high-performance construction applications.

RESUMEN

BACKGROUND: Previous observational studies have revealed a potentially robust bidirectional relationship between frailty and low back pain (LBP). However, the precise causal relationship remains unclear. METHODS: To examine the potential causal association between frailty and LBP, we conducted bidirectional two-sample Mendelian randomization analysis (MR) study. Genetic data on frailty index (FI) and LBP were acquired from publicly available genome-wide association studies (GWAS). Various MR methodologies were utilized, such as inverse variance weighting (IVW), weighted median, and MR-Egger, to evaluate causality. Additionally, sensitivity analyses were conducted to evaluate the robustness of the findings. RESULTS: Genetically predicted higher FI (IVW, odds ratio [OR] = 1.66, 95% CI 1.17-2.36, p = 4.92E-03) was associated with a higher risk of LBP. As for the reverse direction, genetic liability to LBP showed consistent associations with a higher FI (IVW, OR = 1.13, 95% CI 1.07-1.19, p = 2.67E-05). The outcomes from various MR techniques and sensitivity analyses indicate the robustness of our findings. CONCLUSION: Our research findings provide additional evidence bolstering the bidirectional causal relationship between frailty and LBP.

Asunto(s)

RESUMEN

BACKGROUND: Percutaneous balloon compression (PBC) is an effective, low-cost, and simple treatment for primary trigeminal neuralgia (TN). However, PBC has poor efficacy and no better solution for the third branch (V3) of TN. METHODS: Clinical data of 52 patients with trigeminal neuralgia treated with PBC were retrospectively analyzed. Postoperative numbness of the patient was evaluated by facial numbness at the Barrow Neurological Institute (BNI-N). The main observation was the incidence of higher numbness in the V3 than in the other two branches or equally strong numbness in the three branches in the immediate postoperative period. RESULTS: The efficacy values in the pear-shaped balloon group at the first postoperative day (T1), the first month (T2), in the third month (T3), and the sixth month (T4) were 96.7%, 93.3%, 93.3%, and 90%, respectively, and 1 patient (3.3%) had recurrence. The efficacy value for the extracapsular capsule group was 95.5% at all times and there were no patients with recurrence within 6 months after surgery. In the immediate postoperative period, the effective compression rate of V3 in the pear-shaped balloon group was 43.3%, and 86.4% in the extracapsular capsule group (P = 0.020). At six months of follow-up, the effective compression rate of V3 was higher in the extracapsular capsule group than in the pear-shaped balloon group. CONCLUSIONS: The riveted structure of the extracapsular capsule can effectively compress V3, thus performing PBC with a balloon shaped as an extracapsular capsule is a new, effective, and safe treatment option for TN V3. TRIAL REGISTRATION: ClinicalTrials.gov ChiCTR2300067313.

Asunto(s)

RESUMEN

AIM: Choosing the initial treatment for type 2 diabetes (T2D) is pivotal, requiring consideration of solid clinical evidence and patient characteristics. Despite metformin's historical preference, its efficacy in preventing cerebrovascular events lacked empirical validation. This study aimed to evaluate the associations between first-line monotherapy (metformin or non-metformin antidiabetic medications) and cerebrovascular complications in patients with T2D without diabetic complications. METHODS: We analysed 9090 patients with T2D without complications who were prescribed either metformin or non-metformin medications as initial therapy. Propensity score matching ensured group comparability. Cox regression analyses, stratified by initial metformin use, assessed cerebrovascular disease risk, adjusting for multiple covariates and using competing risk analysis. Metformin exposure was measured using cumulative defined daily doses. RESULTS: Metformin users had a significantly lower crude incidence of cerebrovascular diseases compared with non-users (p < .0001). Adjusted hazard ratios (aHRs) consistently showed an association between metformin use and a lower risk of overall cerebrovascular diseases (aHRs: 0.67-0.69) and severe events (aHRs: 0.67-0.69). The association with reduced risk of mild cerebrovascular diseases was significant across all models (aHRs: 0.73-0.74). Higher cumulative defined daily doses of metformin correlated with reduced cerebrovascular risk (incidence rate ratio: 0.62-0.94, p < .0001), indicating a dose-dependent effect. CONCLUSION: Metformin monotherapy is associated with a reduced risk of cerebrovascular diseases in early-stage T2D, highlighting its dose-dependent efficacy. However, the observed benefits might also be influenced by baseline differences and the increased risks associated with other medications, such as sulphonylureas. These findings emphasize the need for personalized diabetes management, particularly in mitigating cerebrovascular risk in early T2D stages.

Asunto(s)

RESUMEN

Liquid-liquid phase separation (LLPS) within cells gives rise to membraneless organelles, which play pivotal roles in numerous cellular functions. A comprehensive understanding of the functional aspects of intrinsically disordered protein (IDP) condensates necessitates elucidating their inherent structures and establishing correlations with biological functions. Coarse-grained (CG) molecular dynamics (MD) simulations present a promising avenue for gaining insights into LLPS mechanisms of biomacromolecules. Essential to this endeavor is the development of tailored CG force fields for MD simulations, incorporating the full spectrum of biomolecules involved in the formation of condensates and accounting for real-time biochemical reactions coupled to the LLPS. Moreover, developing accurate theoretical frameworks and establishing links between condensate structure and its function are imperative for a thorough comprehension of LLPS of biological systems.

Asunto(s)

RESUMEN

Surgical indications for patients with pulmonary arterial hypertension (PAH) and congenital heart defects are controversial. The treat and repair strategy has demonstrated efficacy in adult populations, but there have been no studies on pediatric patients. This study included pediatric patients with PAH and simple congenital heart defects who underwent corrective repair between 2012 and 2021. According to the preoperative treatment strategies, the patients were divided into a regular strategy group (Group 1) and a treat-and-repair strategy group (Group 2). Postoperative recovery and follow-up results were compared between the two groups. A total of 33 patients were included in this study. Group 1 consisted of 19 patients, whereas Group 2 consisted of 14 patients. The pulmonary vascular resistance index in Group 2 was higher than that in Group 1 (10.9 ± 4.1 vs. 8.2 ± 1.6 WU, p = 0.031). There were no differences in postoperative recovery between the two groups (p > 0.05). During follow-up, five patients were lost (three in Group 1 and two in Group 2). The median follow-up period was 59 months. One patient died in Group 1, and two patients died in Group 2. There was no significant difference in the survival curve (p = 0.39). At the last follow-up, another seven patients had experienced a non-low-risk condition, with a total of three non-low-risk patients in Group 1 and seven in Group 2, including one patient in each group who had a history of ICU admission. According to the ROC curve, a preoperative PVRi <8.2 WU×m2 can predict postoperative persistent low-risk state, PVRi <5.2 WU×m2 can avoid postoperative death and/or ICU administration. In pediatric patients with PAH and simple congenital heart defects, the treat and repair strategies may provide surgery opportunities, PVRi should be <8 WU×m2, and <5.2 WU×m2 is the best choice.

RESUMEN

Colloidal molecule clusters (CMCs) are promising building blocks with molecule-like symmetry, offering exceptional synergistic properties for applications in plasmonics and catalysis. Traditional CMC fabrication has been limited to simple molecule-like structures utilizing isotropic particles. Here, we employ molecular dynamics simulation to investigate the co-assembly of anisotropic nanorods (NRs) and the stimulus-responsive polymer (SRP) via reversible adsorption. The results of the simulation show that it is possible to fabricate hypercoordination complex structures with high symmetry from the co-assembly of NRs and the SRP, even in analogy to the Th(BH4)4 structure. The coordination number of these CMCs can be precisely programmed by adjusting the shape and size of the ends of the NRs and the SRP cohesion energy. Furthermore, a finite-difference time-domain simulation indicates these hypercoordination structures exhibit significantly enhanced optical activity and plasmonic coupling effects. These findings introduce a new design approach for complex molecule-like structures utilizing anisotropic nanoparticles and may expand the applications of CMCs in photonics.

RESUMEN

The coarse-grained (CG) model serves as a powerful tool for the simulation of polymer systems; its reliability depends on the accurate representation of both structural and dynamical properties. However, strong correlations between structural and dynamical properties on different scales and also a strong memory effect, enforced by chain connectivity between monomers in polymer systems, render developing a chemically specific systematic CG model a formidable task. In this study, we report a systematic CG approach that combines the iterative Boltzmann inversion (IBI) method and the generalized Langevin equation (GLE) dynamics. Structural properties are ensured by using conservative CG potentials derived from the IBI method. To retrieve the correct dynamical properties in the system, we demonstrate that using a combination of a Rouse-type delta function and a time-dependent short-time kernel in the GLE simulation is practically efficient. The former can be used to adjust the long-time diffusion dynamics, and the latter can be reconstructed from an iterative procedure according to the velocity autocorrelation function (ACF) from all-atomistic (AA) simulations. Taking the polystyrene as an example, we show that not only structural properties of radial distribution function, intramolecular bond, and angle distributions can be reproduced but also dynamical properties of mean-square displacement, velocity ACF, and force ACF resulted from our CG model have quantitative agreement with the reference AA model. In addition, reasonable agreements are observed in other collective properties between our GLE-CG model and the AA simulations as well.

RESUMEN

Supported lipid bilayers (SLBs), two-dimensional lipid films formed on a solid-supporting substrate, serve as models for biomembranes and exhibit remarkable potential in chemistry, biology, and medicine. However, preparing SLBs with highly negatively charged contents on the negatively charged surface by overcoming electrostatic repulsion remains a challenge. Here, a creative bicelle-mediated and divalent cation-free SLB preparation method with the assistance of phosphate-buffered saline (PBS) solution was proposed, which can form the SLBs containing 50% DOPS or 30% CL on the silica surface monitored by a quartz crystal microbalance with dissipation (QCM-D). Results of molecular dynamics (MD) simulation indicate that electrostatic repulsion can be overcome by the increased number of hydrogen bonds caused by the adsorption of dihydrogen phosphate ions onto the headgroups of lipids. In addition, the negatively charged SLB formation was identified to be a three-step kinetic process, which differs from a two-step mechanism in the case of amphoteric SLB. The extra kinetic step can be attributed to the reduction in the number of intermolecular hydrogen bonds and the ordering of water molecules in the hydration layer. This investigation resolves the challenge of fabricating SLB over negatively charged surfaces and offers a fresh perspective on the SLB assembly methodology.

RESUMEN

The collapse or folding of an individual polymer chain into a nanoscale particle gives rise to single-chain nanoparticles (SCNPs), which share a soft nature with biological protein particles. The precise control of their properties, including morphology, internal structure, size, and deformability, are a long-standing and challenging pursuit. Herein, a new strategy based on amphiphilic alternating copolymers for producing SCNPs with ultrasmall size and uniform structure is presented. SCNPs are obtained by folding the designed alternating copolymer in N,N-dimethylformamide (DMF) and fixing it through a photocatalyzed cycloaddition reaction of anthracene units. Molecular dynamics simulation confirms the solvophilic outer corona and solvophobic inner core structure of SCNPs. Furthermore, by adjusting the length of PEG units, precise control over the mean size of SCNPs is achieved within the range of 2.8 to 3.9 nm. These findings highlight a new synthetic strategy that enables enhanced control over morphology and internal structure while achieving ultrasmall and uniform size for SCNPs.

Asunto(s)

RESUMEN

Objectives: With the development of perioperative treatment, the results of the unifocalization and corrective repair of pulmonary atresia/ventricular septal defect with major aortopulmonary collateral arteries have been significantly improved. However, the in-hospital recovery is quite different individually. Therefore, it is essential to find prognostic indicators to avoid unsatisfactory recovery. Design: This was a case-control study. Setting: The study was conducted in the national center for cardiovascular diseases in China. Participants: Pediatric patients between 2014 and 2022. Interventions: None. Measurements & main results: A total of 19 patients were included. The possible prognostic indicators included were commonly used clinical data. Unsatisfactory postoperative recovery was defined as mechanical ventilation≥ 7 days and/or in-hospital death. Satisfactory postoperative recovery was defined as mechanical ventilation<7 days and survival at discharge. We separated patients into two groups and compared the peri-operative data through univariable analysis. There were 8 patients in unsatisfactory recovery group (including 1 death) and 11 patients in satisfactory recovery group. Among all the possible prognostic indicators, through univariable analysis, pulmonary arterial pressure in pulmonary flow study was statistically different (p = 0.027 < 0.05). The ROC curve showed that the area under curve and cut-off values in predicting satisfactory recovery were 0.841 and 22 mmHg; the corresponding sensitivity and specificity were 100% and 72.7%. There was no statistical difference between the two groups in ventricular septal fenestration and pulmonary hypertension targeting drugs. Conclusion: A pulmonary arterial pressure <22 mmHg in pulmonary flow study may avoid unsatisfactory in-hospital recovery after unifocalization and corrective repair of pulmonary atresia/ventricular septal defect with major aortopulmonary collateral arteries.

RESUMEN

The application of liquid crystal technology typically relies on the precise control of molecular orientation at a surface or interface. This control can be achieved through a combination of morphological and chemical methods. Consequently, variations in constrained boundary flexibility can result in a diverse range of phase behaviors. In this study, we delve into the self-assembly of liquid crystals within elastic spatial confinement by using the Gay-Berne model with the aid of molecular dynamics simulations. Our findings reveal that a spherical elastic shell promotes a more regular and orderly alignment of liquid crystals compared to a hard shell. Moreover, during the cooling process, the hard-shell confined system undergoes an isotropic-smectic phase transition. In contrast, the phase behavior within the spherical elastic shell closely mirrors the isotropic-nematic-smectic phase transition observed in bulk systems. This indicates that the orientational arrangement of liquid crystals and the deformations induced by a flexible interface engage in a competitive interplay during the self-assembly process. Importantly, we found that phase behavior could be manipulated by altering the flexibility of the confined boundaries. This insight offers a fresh perspective for the design of innovative materials, particularly in the realm of liquid crystal/polymer composites.

RESUMEN

The organic modification of montmorillonite was successfully achieved using cetyltrimethyl ammonium bromide under facile conditions. The modified montmorillonite was subsequently used for the fabrication of montmorillonite-induced nanopore-rich cement paste (MNCP), and the shrinkage behavior and fundamental performance of MNCP were also investigated. The results indicate that alkali cations on a montmorillonite layer surface were exchanged by using CTAB under 80 °C, successfully achieving the organic modification of montmorillonite. As a pore-forming agent, the modified montmorillonite caused a reduction in shrinkage: the 28-day autogenous shrinkage at a design density of 400 kg/m3 and 800 kg/m3 was reduced to 2.05 mm/m and 0.24 mm/m, and the highest reduction percentages during the 28-day drying shrinkage were 68.1% and 62.2%, respectively. The enlarged interlamellar pores and hydrophobic effects caused by the organic modification of montmorillonite aided this process. Organic-modified montmorillonite had a minor influence on dry density and thermal conductivity and could contribute to an enhancement of strength in MNCP.

RESUMEN

This study aimed to investigate whether sarcopenia independently increases the risk of diabetes-induced dementia in elderly individuals diagnosed with type 2 diabetes mellitus. The study cohort consisted of a large sample of elderly individuals aged 60 years and above, who were diagnosed with type 2 diabetes mellitus between 2008 and 2018. To minimize potential bias and achieve covariate balance between the sarcopenia and non-sarcopenia groups, we employed propensity score matching. Various statistical analyses, including Cox regression models to assess dementia risk and associations, competing risk analysis to account for mortality and Poisson regression analysis for incidence rates, were used. Before propensity score matching, the study included 406 573 elderly type 2 diabetes mellitus patients, with 20 674 in the sarcopenia group. Following propensity score matching, the analysis included a total of 41 294 individuals, with 20 647 in the sarcopenia group and 20 647 in the non-sarcopenia group. Prior to propensity score matching, elderly type 2 diabetes mellitus patients with sarcopenia exhibited a significantly higher risk of dementia (adjusted hazard ratio: 1.12, 95% confidence interval: 1.07-1.17). After propensity score matching, the risk remained significant (adjusted hazard ratio: 1.14, 95% confidence interval: 1.07-1.21). Incidence rates of dementia were notably higher in the sarcopenia group both before and after propensity score matching, underscoring the importance of sarcopenia as an independent risk factor. Our study highlights sarcopenia as an independent risk factor for diabetes-induced dementia in elderly type 2 diabetes mellitus patients. Advanced age, female gender, lower income levels, rural residency, higher adapted diabetes complication severity index and Charlson Comorbidity Index scores and various comorbidities were associated with increased dementia risk. Notably, the use of statins was linked to a reduced risk of dementia. This research underscores the need to identify and address modifiable risk factors for dementia in elderly type 2 diabetes mellitus patients, offering valuable insights for targeted interventions and healthcare policies.

RESUMEN

[This corrects the article DOI: 10.1039/C8SC02847H.].

RESUMEN

Molecular dynamics simulations were used to analyze the mechanical properties and failure processes of poly(p-phenylene-terephthalamide) (PPTA), poly(p-phenylene-benzimidazole-terephthalamide) (PBIA), PBIA-PPTA (formed by 1:1 copolymerization of PPTA and PBIA), and poly(p-phenylene-benzobisoxazole) (PBO) crystals at different strain rates and temperatures. The failure stress and strain were found to be linear with the temperature and logarithmic strain rate. Moreover, based on the kinetic theory of fracture and the comprehensive simulation results, we formulated a model that describes the failure stress of the aforementioned crystals under varying strain rates and temperatures. Through the analysis of the failure process, we found that in PPTA, PBIA, and PBIA-PPTA crystals, the bond failure probability is correlated with the strain rate and temperature. The examination of bond lengths and angles unveiled that bonds with larger initial aligning angles are more susceptible to failure during the strain process. Intriguingly, the stretching process induced a conformational change in the PBO molecular chain, leading to a deviation from the linear relation in its stress-strain curve.

RESUMEN

How to fabricate perpendicularly oriented domains (PODs) of lamellar and cylinder phases in block copolymer thin films remains a major challenge. In this work, via a coarse-grained molecular dynamics simulation study, we report a solvent evaporation strategy starting from a mixed solution of A-b-B-type diblock copolymers (DBCs) and single-chain nanoparticles (SCNPs) with the same composition, which is capable of spontaneously generating PODs in drying DBC films induced by the interface segregation of SCNPs. The latter occurs at both the free surface and substrate and, consequently, neutralizes the interface selectivity of distinct blocks in DBCs, leading to spontaneous formation of PODs at both interfaces. The interface segregation of SCNPs is related to the weak solvophilicity of the internal cross-linker units. A mean-field theory calculation demonstrates that the increase in the chemical potential of SCNPs in the bulk region drives their interface segregation along with solvent evaporation. We believe that such a strategy can be useful in regulating the PODs of DBC films in practical applications.

RESUMEN

Neuropathic pain (NP) is an intractable pain that results from primary nervous system injury and dysfunction. Herein, we demonstrated in animal models that peripheral nerve injury induced enhanced pain perception and anxiety-like behaviors. According to previous reports, nucleus accumbens (NAc) shell is required for complete expression of neuropathic pain behaviors and mood alternations, we found the elevated mRNA and protein level of Prokineticin-2 (Prok2) in the NAc shell after Chronic Constriction Injury (CCI). Prok2 knockdown in the NAc shell reversed NP and anxiety-like behaviors in rats, indicating that Prok2 might play a fundamental role in NP and anxiety co-morbidity. CCI significantly enhanced Prok2 co-expression with NF-κB P-p65 in comparison with control animals. In addition to reversing the established nociceptive hypersensitivities and anxiety simultaneously, NAc microinjection of NF-κB siRNA or specific inhibitor PDTC reversed Prok2 upregulation. Besides, Prok2 was significantly decreased in vitro when co-transfected with si-NF-κB. Dual-Luciferase assay showed NF-κB directly activated Prok2 gene transcriptional activity. Overall, these findings provide new insights into the neurobiological mechanisms behind NP and comorbid anxiety. The NF-κB/Prok2 pathway could be a potential therapeutic target for NP and anxiety disorders.

RESUMEN

Assembly of nanoparticles into macroscopic materials with mechanical robustness, green processability, and recastable ability is an important and challenging task in materials science and nanotechnology. As an emerging nanoparticle with superior properties, macroscopic materials assembled from carbon dots will inherit their properties and further offer collective properties; however, macroscopic materials assembled from carbon dots solely remain unexplored. Here we report macroscopic films assembled from carbon dots modified by ureido pyrimidinone. These films show tunable fluorescence inherited from carbon dots. More importantly, these films exhibit collective properties including self-healing, re-castability, and superior mechanical properties, with Young's modulus over 490 MPa and breaking strength over 30 MPa. The macroscopic films maintain original mechanical properties after several cycles of recasting. Through scratch healing and welding experiments, these films show good self-healing properties under mild conditions. Moreover, the molecular dynamics simulation reveals that the interplay of interparticle and intraparticle hydrogen bonding controls mechanical properties of macroscopic films. Notably, these films are processed into diverse shapes by an eco-friendly hydrosetting method. The methodology and results in this work shed light on the exploration of functional macroscopic materials assembled from nanoparticles and will accelerate innovative developments of nanomaterials in practical applications.

RESUMEN

Background: Bone cancer pain (BCP) is one of the most ubiquitous and refractory symptoms of cancer patients that needs to be urgently addressed. Substantial studies have revealed the pivotal role of Cav3.2 T-type calcium channels in chronic pain, however, its involvement in BCP and the specific molecular mechanism have not been fully elucidated. Methods: The expression levels of Cav3.2, insulin-like growth factor 1(IGF-1), IGF-1 receptor (IGF-1R) and hypoxia-inducible factor-1α (HIF-1α) were detected by Western blot in tissues and cells. X-ray and Micro CT used to detect bone destruction in rats. Immunofluorescence was used to detect protein expression and spatial location in the spinal dorsal horn. Electrophoretic mobility shift assay used to verify the interaction between HIF-1α and Cav3.2. Results: The results showed that the expression of Cav3.2 channel was upregulated and blockade of this channel alleviated mechanical allodynia and thermal hyperalgesia in BCP rats. Additionally, inhibition of IGF-1/IGF-1R signaling not only reversed the BCP-induced upregulation of Cav3.2 and HIF-1α, but also decreased nociceptive hypersensitivity in BCP rats. Inhibition of IGF-1 increased Cav3.2 expression levels, which were abolished by pretreatment with HIF-1α siRNA in PC12 cells. Furthermore, nuclear HIF-1α bound to the promoter of Cav3.2 to regulate the Cav3.2 transcription level, and knockdown of HIF-1α suppresses the IGF-1-induced upregulation of Cav3.2 and pain behaviors in rats with BCP. Conclusion: These findings suggest that spinal Cav3.2 T-type calcium channels play a central role during the development of bone cancer pain in rats via regulation of the IGF-1/IGF-1R/HIF-1α pathway.