A Non-Invasive Method for Generating the Cyclic Loading-Induced Intra-Articular Cartilage Lesion Model of the Rat Knee

The pathophysiology of primary osteoarthritis (OA) remains unclear. However, a specific subclassification of OA in relatively younger age groups is likely correlated with a history of articular cartilage damage and ligament avulsion. Surgical animal models of OA of the knee play an important role in understanding the onset and progression of post-traumatic OA and aid in the development of novel therapies for this disease. However, non-surgical models have been recently considered to avoid traumatic inflammation that could affect the evaluation of the intervention. In this study, an intra-articular cartilage lesion rat model induced by in vivo cyclic compressive loading was developed, which allowed researchers to (1) determine the optimal magnitude, speed, and duration of load that could cause focal cartilage damage; (2) assess post-traumatic spatiotemporal pathological changes in chondrocyte vitality; and (3) evaluate the histological expression of destructive or protective molecules that are involved in the adaptation and repair mechanisms against joint compressive loads. This report describes the experimental protocol for this novel cartilage lesion in a rat model

Place perception and restorative experience of recreationists in the natural environment of rural tourism

IntroductionIn contemporary society, people spend long periods under high stress, and tourism activities have gradually been internalized as a new means of stress release and self-recovery. Studies have found that the high-quality natural environment of rural tourism destinations has a higher restorative effect than other places, and the rural natural environment can provide psychological recovery to visitors on top of offering visual beauty and other experiences.MethodsThis paper starts with the relationship between rural place perception and restorative experience evaluation. Based on theories such as the restorative environments theory, we investigates whether rural natural environmental factors have a restorative effect on recreationists through collecting 300 questionnaires and using SPSS 26.0 structural equation modeling for analysis.ResultsThe study found that there is a positive correlation between rural natural perception, place dependence, and restorative experience, forming a positive feedback loop dynamic system. The analysis suggests that enhancing the perception of the rural natural environment and place attachment can improve the restorative experience of recreationists in rural settings.DiscussionThis research establishes a systematic research framework for the relationship between rural natural perception, place attachment, and restorative experience, to deeply understand the dynamic interaction between them. It reveals the relationship between rural natural perception and restorative experience, suggesting that enriching the perceptual elements in rural natural spaces can meet the diverse needs of recreationists, enhance the sense of dependence and identification with rural spaces, and thus promote the psychological well-being and restorative experience of recreationists. The study also finds that place dependence plays a mediating role between rural natural perception and restorative experience. Place attachment and place identity, as mediating variables, act as bridges and catalysts in the process of rural natural perception affecting restorative experience

One session of 20 ​N cyclic compression induces chronic knee osteoarthritis in rats: A long-term study

OBJECTIVE: Mechanical stimulation is a risk factor for knee osteoarthritis. Non-surgical compression has been used to study the effects of mechanical stimulation in vivo. However, the long-term effects of low-force compression on knee joint had not been studied. Therefore, we sought to identify the long-term effects of low-force cyclic compression on the rat knee joint. DESIGN: In this study, we applied one session cyclic compression with a peak load of 20 ​N for 60 cycles to the rat knee joint in an approximately 140-degree flexion position (Wistar, male, 12 weeks old), followed by 1 year of observation (including data from 1 week, 2 weeks, 4 weeks, 8 weeks, 6 months, and 1 year after compression), and then performed a sub-regional analysis with hematoxylin-eosin, Safranin O and Fast Green, and MMP13 immunohistochemical staining. RESULTS: We observed osteoarthritis-like cartilage damage, synovial inflammation, and high expression of MMP13 within 1 year after compression. However, these changes progressed slowly, with obvious matrix cracks that did not appear until 1 year after compression. In the regional analysis, we found that low-force compression caused a much slower development of injury at the compression contact site, and no significant structural cartilage damage was observed after 1 year of compression. In contrast, the non-contact site during compression at tibial cartilage in the same joint was the first to show significant structural damage. CONCLUSION: This study demonstrates that one session of 20 ​N cyclic compression induces a chronic osteoarthritis-like phenotype in the rat knee in the long term

Explanation of hand, foot, and mouth disease cases in Japan using Google Trends before and during the COVID-19: infodemiology study

[Background] Coronavirus Disease 2019 (COVID-19) pandemic affects common diseases, but its impact on hand, foot, and mouth disease (HFMD) is unclear. Google Trends data is beneficial for approximate real-time statistics and because of ease in access, is expected to be used for infection explanation from an information-seeking behavior perspective. We aimed to explain HFMD cases before and during COVID-19 using Google Trends. [Methods] HFMD cases were obtained from the National Institute of Infectious Diseases, and Google search data from 2009 to 2021 in Japan were downloaded from Google Trends. Pearson correlation coefficients were calculated between HFMD cases and the search topic “HFMD” from 2009 to 2021. Japanese tweets containing “HFMD” were retrieved to select search terms for further analysis. Search terms with counts larger than 1000 and belonging to ranges of infection sources, susceptible sites, susceptible populations, symptoms, treatment, preventive measures, and identified diseases were retained. Cross-correlation analyses were conducted to detect lag changes between HFMD cases and search terms before and during the COVID-19 pandemic. Multiple linear regressions with backward elimination processing were used to identify the most significant terms for HFMD explanation. [Results] HFMD cases and Google search volume peaked around July in most years, excluding 2020 and 2021. The search topic “HFMD” presented strong correlations with HFMD cases, except in 2020 when the COVID-19 outbreak occurred. In addition, the differences in lags for 73 (72.3%) search terms were negative, which might indicate increasing public awareness of HFMD infections during the COVID-19 pandemic. The results of multiple linear regression demonstrated that significant search terms contained the same meanings but expanded informative search content during the COVID-19 pandemic. [Conclusions] The significant terms for the explanation of HFMD cases before and during COVID-19 were different. Awareness of HFMD infections in Japan may have improved during the COVID-19 pandemic. Continuous monitoring is important to promote public health and prevent resurgence. The public interest reflected in information-seeking behavior can be helpful for public health surveillance

Effects of Spermidine on Cell Proliferation, Migration, and Inflammatory Response in Porcine Enterocytes.

peer reviewed[en] BACKGROUND: Polyamines have been demonstrated to be beneficial to porcine intestinal development. Our previous study showed that putrescine mitigates intestinal atrophy in weanling piglets and suppresses inflammatory response in porcine intestinal epithelial cells, it is still unknown the role of spermidine in mediating putrescine function. OBJECTIVE: The current study aimed to investigate the effect of spermidine on the proliferation, migration, and inflammatory response in porcine intestinal epithelial cells (IPEC-J2 cell line). METHODS: The effects of spermidine on proliferation and migration of IPEC-J2 cells were measured. Difluoromethyl ornithine (DFMO) and diethylglyoxal bis (guanylhydrazone) (DEGBG) were used to block the production of putrescine and spermidine, respectively. A cell inflammation model was established with lipopolysaccharides (LPS) stimulation. Gene expression and protein abundance were determined by real-time quantitative PCR and western blotting, respectively. RESULT: Spermidine significantly enhanced cell proliferation in DFMO (or/and) DEGBG treated IPEC-J2 cells (p 0.05). Similarly, spermidine but not putrescine significantly elevated the rate of migration in DEGBG treated IPEC-J2 cells (p < 0.05). Spermidine deprivation by DEGBG dramatically enhanced mRNA abundance of pro-inflammatory cytokines IL-8, IL-6, and TNF-α (p < 0.05), and the addition of spermidine attenuated excessive expression of those inflammatory pro-inflammatory cytokines, moreover, spermidine but not putrescine suppressed the phosphorylation of NF-κB induced by DEGBG. Spermidine supplementation also significantly suppressed LPS-induced the expression of TNF-α. CONCLUSIONS: The present study highlights a novel insight that putrescine may be converted into spermidine to modulate cell proliferation, migration, and inflammatory response on porcine enterocytes

Nano α-FeOOH Modified Carbon Paste Electrode for Arsenic Determination in Natural Waters

A novel method for determination of inorganic arsenic in natural water, based on nano ferric hydroxides (FeOOH) preconcentration and electrochemistry detection has been developed. As the nano α-FeOOH could successfully act as the adsorbent and electrode matrix modifier, the method presents great potential in practical routine analysis of inorganic arsenic. With optimization of the experimental conditions, nano α-FeOOH modified carbon paste electrode (α-FeOOH@CPE) was obtained by mixing 0.03 g of nano α-FeOOH and 0.02 g graphite powder in n-eicosane as an adhesive and then embedding them in a Teflon tube. Cyclic voltammetry, chronoamperometry and high resolution transmission electron microscopy were used to check and confirm the presence of nano α-FeOOH on the carbon paste electrodes. According to the results, α-FeOOH@CPE showed a considerably higher response to As(III) in comparison with the bare CPE, indicating the α-FeOOH has well selective enrichment for As(III). The developed modified electrode showed a linear range of 1.0 × 10-8 ~ 2.0 × 10-5 mol·L-1 and detection limit of 5.0 nmol·L-1 (S/N = 3). The newly prepared carbon paste electrode was successfully applied for As(III) determination in Yangzonghai Lake water with RSD of less than 3.6 % (n = 3) and recovery in the range of 100.7 ~ 115.0 %. DOI: http://dx.doi.org/10.5755/j01.ms.24.4.18499</p

Broad and strong memory CD4(+)and CD8(+)T cells induced by SARS-CoV-2 in UK convalescent individuals following COVID-19

The development of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines and therapeutics will depend on understanding viral immunity. We studied T cell memory in 42 patients following recovery from COVID-19 (28 with mild disease and 14 with severe disease) and 16 unexposed donors, using interferon-γ-based assays with peptides spanning SARS-CoV-2 except ORF1. The breadth and magnitude of T cell responses were significantly higher in severe as compared with mild cases. Total and spike-specific T cell responses correlated with spike-specific antibody responses. We identified 41 peptides containing CD4+ and/or CD8+ epitopes, including six immunodominant regions. Six optimized CD8+ epitopes were defined, with peptide–MHC pentamer-positive cells displaying the central and effector memory phenotype. In mild cases, higher proportions of SARS-CoV-2-specific CD8+ T cells were observed. The identification of T cell responses associated with milder disease will support an understanding of protective immunity and highlights the potential of including non-spike proteins within future COVID-19 vaccine design

Adaptive Control of Chemical Reactions in the Absence of Reaction Kinetics Information

In this thesis, we develop a passivity-based adaptive control framework for controlling nonlinear processes with uncertainty. The development of the method is motivated by the question whether we can control reaction systems without the knowledge of reaction kinetics. The proposed adaptive control framework incorporates the measurements’derivative information in order to estimate the uncertainty involved in output dynamics. The output dynamics is assumed to take a special control-affine structure, and by using the output’s derivative information we can avoid using internal state dynamics, which is not usually available. Passivity theory is applied for control and estimation designs and overall closed-loop stability is achieved. By extending the passivity-based control to systems with relative degree higher than one throughbackstepping, we can obtain cascade feedback schemes with PID controllers that overall control convergence is guaranteed. The proposed framework allows us to control reaction systems without knowing the reaction kinetics, and estimate unmeasured compositions by utilizing theavailable partially linear structure of internal dynamics. A reactor temperature control problem that usually has high relative degree is used to illustrate the applicationof passivity-based backstepping control, and results from industrial trials are presented