Control of Nonlinear Distributed Parameter Systems Based on Global Approximation

We extend an iterative approximation method to nonlinear, distributed parameter systems given by partial differential and functional equations. The nonlinear system is approached by a sequence of linear time-varying systems, which globally converges in the limit to the original nonlinear systems considered. This allows many linear control techniques to be applied to nonlinear systems. Here we design a sliding mode controller for a nonlinear wave equation to demonstrate the effectiveness of this method

Screening of Multimeric β-Xylosidases from the Gut Microbiome of a Higher Termite, \u3cem\u3eGlobitermes brachycerastes\u3c/em\u3e

Termite gut microbiome is a rich reservoir for glycoside hydrolases, a suite of enzymes critical for the degradation of lignocellulosic biomass. To search for hemicellulases, we screened 12,000 clones from a fosmid gut library of a higher termite, Globitermes brachycerastes. As a common Southeastern Asian genus, Globitermes distributes predominantly in tropical rain forests and relies on the lignocellulases from themselves and bacterial symbionts to digest wood. In total, 22 positive clones with β-xylosidase activity were isolated, in which 11 representing different restriction fragment length polymorphism (RFLP) patterns were pooled and subjected to 454 pyrosequencing. As a result, eight putative β-xylosidases were cloned and heterologously expressed in Escherichia coli BL21 competent cells. After purification using Ni-NTA affinity chromatography, recombinant G. brachycerastes symbiotic β-xylosidases were characterized enzymatically, including their pH and temperature optimum. In addition to β-xylosidase activity, four of them also exhibited either β-glucosidase or α-arabinosidases activities, suggesting the existence of bifunctional hemicellulases in the gut microbiome of G. brachycerastes. In comparison to multimeric protein engineering, the involvement of naturally occurring multifunctional biocatalysts streamlines the genetic modification procedures and simplifies the overall production processes. Alternatively, these multimeric enzymes could serve as the substitutes for β-glucosidase, β-xylosidase and α-arabinosidase to facilitate a wide range of industrial applications, including food processing, animal feed, environment and waste management, and biomass conversion

The relationship between physical exercise and social adjustment in Chinese university students: the sequential mediating effect of peer attachment and self-esteem

Regular physical exercise is well-documented for its advantages that extend beyond physical health, notably influencing mental and social well-being. This study examines the correlation between physical exercise and social adjustment in Chinese university students (N = 672), with peer attachment and self-esteem acting as significant mediators. The analysis revealed a significant indirect effect through peer attachment (effect = 0.0376, 95% CI [0.0091, 0.0588]), self-esteem (effect = 0.2101, 95% CI [0.2730, 0.3690]), and a sequential mediation pathway (effect = 0.0055, 95% CI [0.0023, 0.0224]). Physical activity promotes social ties by encouraging peer bonding, which subsequently facilitates social adaptation. Moreover, self-esteem, a crucial element of psychological resilience, mediates the relationship between physical exercise and social adaptation. Importantly, a sequential mediation pathway—peer attachment—self-esteem—social adjustment—was supported, suggesting that peer relationships enhance self-esteem, which in turn improves social adaptation. This ordering aligns with theories emphasizing the influence of social feedback on self-concept (e.g., Reflected Appraisals Theory, Sociometer Theory). These findings underscore the comprehensive advantages of physical activity and support efforts to promote exercise in academic settings to facilitate student well-being and psychosocial development

Serum IL-6 level predicts the prognosis and diagnosis in cervical cancer patients

Background: Interleukin-6 (IL-6) has been reported to be associated with the prognosis of cancers. As for cervical cancer (CC), previous studies investigated the association between IL-6 expression in CC tumor tissue and CC prognosis; however, no studies assessed the effects of serum IL-6 levels on the survival of CC. This study aimed to explore the effects of serum IL-6 levels on prognosis in patients with CC. Methods: In total, 327 patients with CC and 355 controls were recruited from this hospital from May 2015 to May 2016. Serum IL-6 levels were measured before treatment. The Kaplan–Meier method was utilized to estimate survival rates. The overall survival (OS) and disease-free survival (DFS) were evaluated. The univariate and multivariate Cox regression analyses were used to identify risk factors associated with the prognosis of CC. Results: We found that the serum IL-6 level in the CC group was significantly higher than that in the control group. The diagnostic value of serum IL-6 level in detecting CC patients was moderate, and the specificity and sensitivity were 77.46% and 47.09%, respectively. Data suggested that the serum IL-6 level was significantly linked with the smoking status, FIGO stage, tumor size, treatment methods, and HPV infection. The univariate and multivariate analysis indicated that FIGO stage IIB-IIIC, lymph node metastasis, and high serum IL-6 levels were negatively associated with the OS and DFS in patients with CC. Conclusion: Serum IL-6 has a moderate diagnostic ability for detecting CC and may be a potential CC biomarker. High serum IL-6 level is associated with adverse prognosis in patients with CC and could be a prognosis indicator for CC patients

Multivariable Super Twisting Based Robust Trajectory Tracking Control for Small Unmanned Helicopter

This paper presents a highly robust trajectory tracking controller for small unmanned helicopter with model uncertainties and external disturbances. First, a simplified dynamic model is developed, where the model uncertainties and external disturbances are treated as compounded disturbances. Then the system is divided into three interconnected subsystems: altitude subsystem, yaw subsystem, and horizontal subsystem. Second, a disturbance observer based controller (DOBC) is designed based upon backstepping and multivariable super twisting control algorithm to obtain robust trajectory tracking property. A sliding mode observer works as an estimator of the compounded disturbances. In order to lessen calculative burden, a first-order exact differentiator is employed to estimate the time derivative of the virtual control. Moreover, proof of the stability of the closed-loop system based on Lyapunov method is given. Finally, simulation results are presented to illustrate the effectiveness and robustness of the proposed flight control scheme

Dinitrogen (N2_{2}) pulse emissions during freeze-thaw cycles from montane grassland soil

Short-lived pulses of soil nitrous oxide (N$_{2}$O) emissions during freeze-thaw periods can dominate annual cumulative N$_{2}$O fluxes from temperate managed and natural soils. However, the effects of freeze thaw cycles (FTCs) on dinitrogen (N$_{2}$) emissions, i.e., the dominant terminal product of the denitrification process, and ratios of N$_{2}$/N$_{2}$O emissions have remained largely unknown because methodological difficulties were so far hampering detailed studies. Here, we quantified both N$_{2}$ and N$_{2}$O emissions of montane grassland soils exposed to three subsequent FTCs under two different soil moisture levels (40 and 80% WFPS) and under manure addition at 80% WFPS. In addition, we also quantified abundance and expression of functional genes involved in nitrification and denitrification to better understand microbial drivers of gaseous N losses. Our study shows that each freeze thaw cycle was associated with pulse emissions of both N$_{2}$O andN$_{2}$, with soil N$_{2}$ emissions exceeding N$_{2}$O emissions by a factor of 5–30. Increasing soil moisture from 40 to 80% WFPS and addition of cow slurry increased the cumulative FTC N$_{2}$ emissions by 102% and 77%, respectively. For N$_{2}$O, increasing soil moisture from 40 to 80% WFPS and addition of slurry increased the cumulative emissions by 147%and 42%, respectively. Denitrification gene cnorB and nosZ clade I transcript levels showed high explanatory power for N$_{2}$O and N$_{2}$ emissions, thereby reflecting both N gas flux dynamics due to FTC and effects of different water availability and fertilizer addition. In agreement with several other studies for various ecosystems, we show here for mountainous grassland soils that pulse emissions of N$_{2}$O were observed during freeze-thaw.More importantly, this study shows that the freeze-thaw N$_{2}$ pulse emissions strongly exceeded those of N$_{2}$O in magnitude, which indicates that N$_{2}$ emissions during FTCs could represent an important N loss pathway within the grassland N mass balances. However, their actual significance needs to be assessed under field conditions using intact plant-soil systems

Association between triglyceride-glucose index and papillary thyroid carcinoma among Chinese adults with thyroid nodules

BackgroundGrowing evidence has demonstrated that the Triglyceride-Glucose (TyG) index, a reliable and widely recognized marker of insulin resistance, is strongly associated with the development various of types of cancer. For instance, previous studies have demonstrated that elevated TyG index levels are significantly associated to an increased risk of different cancers. Insulin resistance, as reflected by the TyG index, may contribute to tumorigenesis through multiple pathways, including promoting cell proliferation, angiogenesis, and inhibiting apoptosis. Despite these findings, research on the association between the TyG index and papillary thyroid carcinoma(PTC) in Chinese populations is scarce. Given the rising thyroid malignancy incidence, clarifying this relationship is crucial for clinical and public health.ObjectiveTo explore the association between the TyG index and papillary thyroid carcinoma prevalence.MethodsThis cross-sectional study included patients who underwent fine-needle aspiration of thyroid nodules at Nanjing Tongren Hospital from June 2018 to December 2024. A multivariate logistic regression model was used to examine the association between the TyG index and papillary thyroid carcinoma. Furthermore, stratification and interaction analyses were performed to assess the stability of the association across various subgroups. Moreover, sensitivity analysis further confirmed the stability of the findings.ResultsThis study ultimately enrolled 396 patients (mean age 47.8 ± 12.7 years,71.0% females), with the TyG index odds ratio increasing across tertiles. Compared to T1, adjusted ORs for T2 and T3 in papillary thyroid carcinoma were 1.28 and 3.37, respectively. Subgroup and sensitivity analyses supported the results.ConclusionsThis study suggests that TyG index may serve as a valid biomarker for the prediction of papillary thyroid carcinoma in patients with thyroid nodules, although large prospective studies are needed to confirm these findings

Effect of ellagitannin metabolites ellagic acid and urolithins A-D on the non-enzymatic glycation of human serum albumin and inhibiting mechanisms

Effect of ellagitannins gut microbiota metabolites ellagic acid (EA) and urolithin A-urolithin D (UroA-UroD) on human serum albumin (HSA) glycation were firstly evaluated in this research. The inhibition mechanisms were investigated by methylglyoxal (MGO) trapping and radical scavenging ability assays, docking studies and nano LC-orbitrap-MS/MS technology. Results indicated that the inhibition of urolithins on HSA glycation was highly positive correlated with the number of phenolic hydroxy groups. Addition of UroD and EA could effectively enhance the content of free amino group, suppress dicarbonyl compounds and advanced glycation end-products (AGEs) formation, alleviated tryptophan and protein oxidation, inhibited HSA amyloid-like aggregation. They could also trap MGO and scavenge 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH·) and 2,2’-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid free radical (ABTS+·). Molecular docking indicated that EA and UroA-UroD interact with HSA mainly through hydrogen bound and hydrophobic interaction, among which 2 or 3 hydrogen bonds were formed. The number of glycation sites were reduced from 11 to 10, 10, 7, and 10, respectively, when 90 μmol/L of EA, UroA, UroC and UroD were added. However, weak inhibition was observed on UroA and UroB. These findings can provide scientific evidence for the application of ellagitannins-rich foods in alleviating diabetic complications

Comparison of cerebrospinal fluid space between probable normal pressure hydrocephalus and Alzheimer’s disease

IntroductionIdiopathic normal pressure hydrocephalus (INPH) is a potentially reversible syndrome characterized by complex symptoms, difficulty in diagnosis and a lack of detailed clinical description, and it is difficult to distinguish from Alzheimer’s disease (AD). The objective of this study was to design a method for measuring the actual amount of hydrocephalus in patients with INPH and to evaluate INPH.MethodsAll subjects underwent a 3D T1-weighted MRI. Statistical parametric mapping 12 was used for preprocessing images, statistical analysis, and voxel-based morphometric gray matter (GM) volume, white matter (WM) volume, and cerebrospinal fluid (CSF) volume analysis. The demographic and clinical characteristics of the groups were compared using a t-test for continuous variables and a chi-square test for categorical variables. Pearson’s correlation analysis and Bonferroni’s statistic-corrected one-way ANOVA were used to determine the relationship among demographic variables. Receiver operating characteristic (ROC) curves were used to assess the accuracy of the callosal angle (CA), WM ratio, and CSF ratio in distinguishing probable INPH from AD.ResultsThe study included 42 patients with INPH, 32 patients with AD, and 24 healthy control subjects (HCs). There were no differences among the three groups in basic characteristics except for Mini-Mental State Examination (MMSE). There was a correlation between the intracranial CSF ratio and CA. The WM ratio and CSF ratio in patients with INPH and AD were statistically different. Furthermore, the combination of CA, WM ratio, and CSF ratio had a greater differential diagnostic value between INPH and AD patients than CA alone.ConclusionINPH can be accurately assessed by measuring intracranial CSF ratio, and the addition of WM ratio and CSF ratio significantly improved the differential diagnostic value of probable INPH from AD compared to CA alone