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Objective: The purpose of this study is to compare the wear properties of UHMWPE acetabular liners after undergoing 3 million (3 Mc) and 5 million (5 Mc) cycles of in-vitro wear testing. The results will serve as a reference for the design of in-vitro testing for hip prostheses and as a control for clinical revision removals. Methods: Wear tests were conducted on three different sizes of acetabular liners (28 mm, 32 mm, and 36 mm internal diameters) using a hip simulator to determine the amount of wear after 3 and 5 million cycles. The analysis included the number, size, and shape of abrasive particles. Results: After 3 and 5 million cycles of wear, the amount of wear on the acetabular liner increased as the inner diameter increased. The abrasive particles had an average equivalent circular area diameter (ECD) of 0.27 µm and 0.29 µm, and 94.4% and 90.1% of the aspect ratio (AR) less than 4. Conclusion: The amount of wear on the acetabular liner after 3 Mc wear can indicate the wear performance of the product. The number of particles increased and the percentage of fibrous particles was higher after 5 Mc wear compared to 3 Mc wear.
Subject(s)
Hip Prosthesis , Materials Testing , Polyethylene , Polyethylenes , Prosthesis Design , Acetabulum , Prosthesis Failure , Equipment Failure AnalysisABSTRACT
The 2023 consensus from the Taiwanese Dermatological Association (TDA) and Taiwan Lung Cancer Society (TLCS) addresses the management of tyrosine kinase inhibitor (TKI)-induced skin toxicities in non-small cell lung cancer (NSCLC). Providing a comprehensive overview, the consensus reflects recent advances in understanding causes and developmental processes of TKI-related skin toxicities. Aimed at guiding clinicians in Taiwan, the consensus integrates new treatment perspectives while incorporating experiences from local dermatology experts. Recommendations underwent a voting process, achieving consensus when 75% or more of experts agreed, leading to their inclusion. Approved by over 90% of participants, the recommended treatment algorithms for major skin toxicities offer valuable insights for clinicians managing TKI-associated effects in NSCLC patients.
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The classification of critical physiological signals using neuromorphic devices is essential for early disease detection. Physical reservoir computing (RC), a lightweight temporal processing neural network, offers a promising solution for low-power, resource-constrained hardware. Although solution-processed memcapacitive reservoirs have the potential to improve power efficiency as a result of their ultralow static power consumption, further advancements in synaptic tunability and reservoir states are imperative to enhance the capabilities of RC systems. This work presents solution-processed electrolyte/ferroelectric memcapacitive synapses. Leveraging the synergistic coupling of electrical double-layer (EDL) effects and ferroelectric polarization, these synapses exhibit tunable long- and short-term plasticity, ultralow power consumption (â¼27 fJ per spike), and rich reservoir state dynamics, making them well-suited for energy-efficient RC systems. The classifications of critical electrocardiogram (ECG) signals, including arrhythmia and obstructive sleep apnea (OSA), are performed using the synapse-based RC system, demonstrating excellent accuracies of 97.8 and 80.0% for arrhythmia and OSA classifications, respectively. These findings pave the way for developing lightweight, energy-efficient machine-learning platforms for biosignal classification in wearable devices.
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Background: Physical activity (PA) exerts an important influence on glycemic control in type 2 diabetes (T2D) patients. Alterations in body composition in patients with T2D may be involved in the overall pathophysiologic process, but PAs and alterations in body composition have been poorly studied. Methods: A total of 615 patients with T2D were selected by convenient sampling. The patients were investigated with the International Physical Activity Questionnaire (IPAQ-S). Moreover, biochemical indices were collected, and the progression of the body composition of the subjects was determined via dual-energy X-ray absorptiometry (DXA). The variables included lumbar bone mineral density (LSBMD), femoral neck bone mineral density (FNBMD), hip bone mineral density (HBMD), whole-body bone mineral density (TBMD), limb skeletal muscle mass index (ASMI), whole-body fat percentage (B-FAT) and trunk fat percentage (T-FAT). Moreover, the levels of physical activity (high level of physical activity [H-PA], medium level of physical activity [M-PA] and low level of physical activity [L-PA]) were divided into three groups to analyze the changes in patient body composition with changes in physical activity level. Results: One-way analysis of variance showed that ß-CTX, TP1NP, HbA1c, B-FAT and T-FAT increased significantly (p<0.05), while 25(OH)D, LSBMD, FNBMD, HBMD, TBMD and ASMI decreased significantly (p<0.001) with the decrease of physical activity. However, there was no significant difference in serum lipids between lnHOMA-ir and lnHOMA-ß (p>0.05). Multiple linear regression model was established to gradually adjust for clinical confounding factors. It was found that physical activity level was independently positively correlated with LSBMD, FNBMD, HBMD, TBMD, and ASMI, and was independently negatively correlated with B-FAT and T-FAT in patients with type 2 diabetes. Conclusion: A lack of physical activity is an independent risk factor for decreased bone mineral density, decreased skeletal muscle content and increased fat content in patients with T2D.
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Rising instances of flash droughts are contributing to notable variability in soil moisture across terrestrial ecosystems. These phenomena challenge urban ecosystem services, yet the reaction of soil ecological functions (SEFs) to such events is poorly understood. This study investigates the responses of SEFs (about nutrient metabolism capacity and potential) and the microbiome under two specific scenarios: a flooding-drought sequence and a direct drought condition. Using quantitative microbial element cycling analysis, high-throughput sequencing, and enzyme activity measurements, we found that unlike in forests, the microbial composition in urban soils remained unchanged during flash drought conditions. However, SEFs were affected in both settings. Correlation analysis and Mantel test showed that forest soils exhibited more complex interactions among soil moisture, properties, and microbial communities. Positive linear correlation revealed that bacteria were the sole drivers of SEFs. Interestingly, while multi-threshold results suggested bacterial α diversity impeded the maximization of SEFs in urban soils, fungi and protists had a beneficial impact. Cross-domain network of urban soils had higher number of nodes and edges, but lower average degree and robustness than forest soils. Mantel test revealed that fungi and protist had significant correlations with bacterial composition in forest soils, but not in urban soils. In the urban network, the degree and eigenvector centrality of bacterial, fungal and protistan ASVs were significantly lower compared to those in the forest. These results suggest that the lower robustness of the microbial network in urban soils is attributed to limited interactions among fungi, consumer protists, and bacteria, contributing to the failure of microbial-driven ecological functions. Overall, our findings emphasize the critical role of fungi and protists in shielding urban soils from drought-induced disturbances and in enhancing the resistance of urban ecological functions amidst environmental changes.
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Oyster reefs are hotspots of denitrification mediated removal of dissolved nitrogen (N), however, information on their denitrifier microbiota is scarce. Furthermore, in oyster aquaculture, triploids are often preferred over diploids, yet again, microbiome differences between oyster ploidies are unknown. To address these knowledge gaps, farmed diploid and triploid oysters were collected over an annual growth cycle and analyzed using shotgun metagenomics and quantitative microbial elemental cycling (QMEC) techniques. Regardless of ploidy, Psychrobacter genus was abundant, with positive correlations found for genes of central metabolism, DNA metabolism, and carbohydrate metabolism. MAGs (metagenome-assembled genomes) yielded multiple Psychrobacter genomes harboring norB, narH, narI, and nirK denitrification genes, indicating their functional relevance within the eastern oysters. QMEC analysis indicated the predominance of carbon (C) and nitrogen (N) cycling genes, with no discernable patterns between ploidies. Among the N-cycling genes, the nosZII clade was overrepresented, suggesting its role in the eastern oyster's N removal processes.
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The electrocatalytic nitrate reduction reaction (NITRR) holds great promise for purifying wastewater and producing valuable ammonia (NH3). However, the lack of efficient electrocatalysts has impeded the achievement of highly selective NH3 synthesis from the NITRR. In this study, we report the design and synthesis of two polynuclear Co-cluster-based coordination polymers, {[Co2(TCPPDA)(H2O)5]·(H2O)9(DMF)} and {Co1.5(TCPPDA)[(CH3)2NH2]·(H2O)6(DMF)2} (namely, NJUZ-2 and NJUZ-3), which possess distinct coordination motifs with well-defined porosity, high-density catalytic sites, accessible mass transfer channels, and nanoconfined chemical environments. Benefitting from their intriguing multicore metal-organic coordination framework structures, NJUZ-2 and NJUZ-3 exhibit remarkable catalytic activities for the NITRR. At a potential of -0.8 V (vs. RHE) in an H-type cell, they achieve an optimal Faradaic efficiency of approximately 98.5% and high long-term durability for selective NH3 production. Furthermore, the electrocatalytic performance is well maintained even under strongly acidic conditions. When operated under an industrially relevant current density of 469.9 mA cm-2 in a flow cell, a high NH3 yield rate of up to 3370.6 mmol h-1 g-1cat. was observed at -0.5 V (vs. RHE), which is 20.1-fold higher than that obtained in H-type cells under the same conditions. Extensive experimental analyses, in combination with theoretical computations, reveal that the great enhancement of the NITRR activity is attributed to the preferential adsorption of NO3- and the reduction in energy input required for the hydrogenation of *NO3 and *NO2 intermediates.
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The global surge in antibiotic resistance genes (ARGs) presents a serious public health challenge. While methods like metagenomic analysis and qPCR arrays have been instrumental in investigating ARG distributions and dynamics, the vast diversity of ARGs often complicates effective monitoring and risk assessment. Here, we developed a High-Risk ARGs (HRA) chip based on high-capacity quantitative PCR array targeting previously identified high-risk ARGs. These ARGs are known to be prevalent in human-related environments, exhibit gene mobility, and are present in ESKAPE pathogens. The HRA chip include 101 primer sets and the 16S rRNA gene as a reference. These primer sets consist of 34 obtained from previous studies, and 67 newly designed primer sets which were validated in silico and experimentally. Absolute quantification of targeted ARGs is accomplished by generating standard curves for all ARGs with serially ten-fold diluted mixed plasmids containing targeted ARG sequences. The amplification efficiencies of all ARGs exceed 99% via plasmid template dilution tests, suggesting high reliability in quantification. The performance of HRA chip is further evaluated by practical applications in environmental samples from wastewater treatment plants (WWTPs) and soils with various land use types and fertilization regimes. The results indicate the dynamics of high-risk ARGs during wastewater treatment process, and reveal the profiles of soil high-risk ARGs which is distinct from those derived via metagenomic approaches. These findings highlight the potentials of HRA Chip in the evaluation of anthropogenic impacts on the environmental resistome with a more focused spectrum of high-risk ARGs. Overall, the HRA Chip emerges as a powerful and efficient high-throughput tool for rapid detection and quantification of high-risk ARGs, facilitating comprehensive profiling of high-risk resistomes in environmental samples which is essential for human health risk assessment of ARGs.
Subject(s)
Real-Time Polymerase Chain Reaction , Real-Time Polymerase Chain Reaction/methods , RNA, Ribosomal, 16S/genetics , Drug Resistance, Microbial/genetics , Environmental Monitoring/methodsABSTRACT
A stable lithium metal-organic framework, constructed using a redox-active N,N,N',N'-tetrakis(4-carboxyphenyl)-1,4-phenylenediamine linker and Li8 cluster-based one-dimensional rod secondary building unit, exhibits good stability and reversible redox activity. The Li8-MOF, which can be oxidized by AgNO3, has the potential to function as an electrochromic device, thereby advancing the development of smart MOF materials.
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BACKGROUND: Detecting event triggers in biomedical texts, which contain domain knowledge and context-dependent terms, is more challenging than in general-domain texts. Most state-of-the-art models rely mainly on external resources such as linguistic tools and knowledge bases to improve system performance. However, they lack effective mechanisms to obtain semantic clues from label specification and sentence context. Given its success in image classification, label representation learning is a promising approach to enhancing biomedical event trigger detection models by leveraging the rich semantics of pre-defined event type labels. RESULTS: In this paper, we propose the Biomedical Label-based Synergistic representation Learning (BioLSL) model, which effectively utilizes event type labels by learning their correlation with trigger words and enriches the representation contextually. The BioLSL model consists of three modules. Firstly, the Domain-specific Joint Encoding module employs a transformer-based, domain-specific pre-trained architecture to jointly encode input sentences and pre-defined event type labels. Secondly, the Label-based Synergistic Representation Learning module learns the semantic relationships between input texts and event type labels, and generates a Label-Trigger Aware Representation (LTAR) and a Label-Context Aware Representation (LCAR) for enhanced semantic representations. Finally, the Trigger Classification module makes structured predictions, where each label is predicted with respect to its neighbours. We conduct experiments on three benchmark BioNLP datasets, namely MLEE, GE09, and GE11, to evaluate our proposed BioLSL model. Results show that BioLSL has achieved state-of-the-art performance, outperforming the baseline models. CONCLUSIONS: The proposed BioLSL model demonstrates good performance for biomedical event trigger detection without using any external resources. This suggests that label representation learning and context-aware enhancement are promising directions for improving the task. The key enhancement is that BioLSL effectively learns to construct semantic linkages between the event mentions and type labels, which provide the latent information of label-trigger and label-context relationships in biomedical texts. Moreover, additional experiments on BioLSL show that it performs exceptionally well with limited training data under the data-scarce scenarios.
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Semantics , Natural Language Processing , Machine Learning , Data Mining/methods , AlgorithmsABSTRACT
OBJECTIVE: Socioeconomic status (SES) has been proven to be associated with chronic obstructive pulmonary disease (COPD) in Western populations, but the evidence is very limited in China. This study aimed to investigate the association between SES and the risk of COPD incident. METHODS: This study was based on the China Kadoorie Biobank (CKB) project in Wuzhong District, Suzhou. A total of 45,484 adults aged 30-79 were included in the analysis during 2004-2008. We used Cox proportional hazard models to investigate the association between SES and the risk of COPD. Household income, education, private property and consumption potential was used to measure SES. Incident COPD cases were ascertained using hospitalization records, death certificates, and active follow-up. RESULTS: A total of 524 COPD cases were identified during a median follow-up of 11.2 years. Household income was inversely associated with the risk of COPD (Ptrend<0.005). The adjusted hazard ratios (95% confidence intervals) for incident COPD were 0.88 (0.69-1.14), 0.77 (0.60-0.99), and 0.42 (0.31-0.57) for participants with annual household income of 10,000 ~ 19,999 yuan, 20,000 ~ 34,999 yuan and ≥ 35,000 yuan respectively, in comparison to participants with an annual household income < 10,000 yuan. Furthermore, we found that education level, refrigerator use, private toilet, private phone, and motor vehicle were adversely associated with COPD risk, while ownership of newly renovated flats was positively correlated with COPD incident. CONCLUSIONS: This prospective study suggests that SES is associated with the risk of COPD in Chinese adults. Population-based COPD prevention strategies tailored for people with different SES could help reduce the burden of COPD in Chinese.
Subject(s)
Pulmonary Disease, Chronic Obstructive , Social Class , Humans , Pulmonary Disease, Chronic Obstructive/epidemiology , China/epidemiology , Middle Aged , Male , Female , Prospective Studies , Adult , Aged , Risk Factors , Proportional Hazards Models , IncidenceABSTRACT
BACKGROUND: The rising prevalence of Type 2 diabetes (T2D) in China poses a critical health challenge, necessitating effective management strategies. The National Essential Public Health Services Program (NEPHSP), initiated in 2009, focuses on equitable access to health services, including T2D management. This study investigates the associations between perceived care quality, self-care behaviors, and glycemic control in Chinese adults with T2D under NEPHSP, particularly examining the mediating role of self-care behaviors. METHODS: Conducted from April to November 2020 in Huai'an City, Jiangsu Province, this study involved 1,577 T2D patients enrolled in NEPHSP. We assessed perceived care quality using the Patient Assessment of Chronic Illness Care (PACIC) scale and developed a comprehensive self-care behavior score, covering nine essential health practices. Glycemic control was evaluated using HbA1c levels. Linear regression models were used to explore these associations, adjusting for demographic and clinical factors, while causal mediation analyses examined the role of intermediate variables. RESULTS: Higher PACIC scores significantly correlated with improved self-care behaviors (ß = 0.294, 95% CI: 0.233 to 0.354) and were negatively associated with HbA1c levels (ß=-0.109, 95% CI: -0.192 to -0.026). The self-care behavior score inversely related to HbA1c levels (ß=-0.197, 95% CI: -0.263 to -0.132). Notably, self-care behaviors mediated 50.41% (P < 0.05) of the effect of perceived care quality on HbA1c levels. CONCLUSIONS: This study demonstrates a substantial association between perceived care quality and better glycemic control in Chinese adults with T2D under NEPHSP, with self-care behaviors playing a crucial mediating role. These findings suggest that patient-centered care and comprehensive self-care practices are essential for effective T2D management within NEPHSP.
Subject(s)
Diabetes Mellitus, Type 2 , Glycemic Control , Quality of Health Care , Self Care , Humans , Diabetes Mellitus, Type 2/therapy , Diabetes Mellitus, Type 2/psychology , Male , Female , Middle Aged , China , Aged , Adult , Glycated Hemoglobin/analysis , Cross-Sectional Studies , East Asian PeopleABSTRACT
Five new sesquiterpenoids, (4S, 5S, 6S, 7S, 8 R)-5,6-dihydroxy-1-acetoxy-10(14)-en-britannilactone (1), (4S, 5 R, 6S, 7S, 8 R)-5,6-dihydroxy-1-acetoxy-10(14)-en-britannilactone (2), 6-O-propionyl-britannilactone (3), 1ß-hydroxy-3α-acetoxyeudesma-11(13)-en-12,8ß-olide (4) and 1ß,5ß-dihydroxyeudesma-11(13)-en-12,8ß-olide (5), along with twelve known ones were isolated from the flowers of Pentanema britannicum (L.) D.Gut.Larr. Among them, compounds 1 and 2 were stereoisomers which belong to 1,10-seco-eudesmane sesquiterpenoid with rare double bond between C-10 and C-14. The structures of the isolated compounds were elucidated by various spectroscopic methods, including 1D and 2D NMR experiments.
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The application of electrically conductive 1D coordination polymers (1D CPs) in nanoelectronic molecular recognition is theoretically promising yet rarely explored due to the challenges in their synthesis and optimization of electrical properties. In this regard, two tetrathiafulvalene-based 1D CPs, namely [Co(m-H2TTFTB)(DMF)2(H2O)]n (Co-m-TTFTB), and {[Ni(m-H2TTFTB)(CH3CH2OH)1.5(H2O)1.5]·(H2O)0.5}n (Ni-m-TTFTB) are successfully constructed. The shorter S···S contacts between the [M(solvent)3(m-H2TTFTB)]n chains contribute to a significant improvement in their electrical conductivities. The powder X-ray diffraction (PXRD) under different organic solvents reveals the flexible and dynamic structural characteristic of M-m-TTFTB, which, combined with the 1D morphology, lead to their excellent performance for sensitive detection of volatile organic compounds. Co-m-TTFTB achieves a limit of detection for ethanol vapor down to 0.5 ppm, which is superior to the state-of-the-art chemiresistive sensors based on metal-organic frameworks or organic polymers at room temperature. In situ diffuse reflectance infrared Fourier transform spectroscopy, PXRD measurements and density functional theory calculations reveal the molecular insertion sensing mechanism and the corresponding structure-function relationship. This work expands the applicable scenario of 1D CPs and opens a new realm of 1D CP-based nanoelectronic sensors for highly sensitive room temperature gas detection.
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ConspectusThe directed synthesis and functionalization of porous crystalline materials pose significant challenges for chemists. The synergistic integration of different functionalities within an ordered molecular material holds great significance for expanding its applications as functional materials. The presence of coordination bonds connected by inorganic and organic components in molecular materials can not only increase the structural diversity of materials but also modulate the electronic structure and band gap, which further regulates the physical and chemical properties of molecular materials. In fact, porous crystalline materials with coordination bonds, which inherit the merits of both organic and inorganic materials, already showcase their superior advantages in optical, electrical, and magnetic applications. In addition to the inorganic components that provide structural rigidity, organic ligands of various types serve as crucial connectors in the construction of functional porous crystalline materials. In addition, redox activity can endow organic linkers with electrochemical activity, thereby making them a perfect platform for the study of charge transfer with atom-resolved single-crystal structures, and they can additionally serve as stimuli-responsive sites in sensor devices and smart materials.In this Account, we introduce the synthesis, structural characteristics, and applications of porous crystalline materials based on the famous redox-active units, tetrathiafulvalene (TTF) and its analogues, by primarily focusing on metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). TTF, a sulfur-rich conjugated molecule with two reversible and easily accessible oxidation states (i.e., radical TTFâ¢+ cation and TTF2+ dication), and its analogues boast special electrical characteristics that enable them to display switchable redox activity and stimuli-responsive properties. These inherent properties contribute to the enhancement of the optical, electrical, and magnetic characteristics of the resultant porous crystalline materials. Moreover, delving into the charge transfer phenomena, which is key for the electrochemical process within these materials, uncovers a myriad of potential functional applications. The Account is organized into five main sections that correspond to the different properties and applications of these materials: optical, electrical, and magnetic functionalities; energy storage and conversion; and catalysis. Each section provides detailed discussions of synthetic methods, structural characteristics, the physical and chemical properties, and the functional performances of highlighted examples. The Account also discusses future directions by emphasizing the exploration of novel organic units, the transformation between radical cation TTFâ¢+ and dication TTF2+, and the integration of multifunctionalities within these frameworks to foster the development of smart materials for enhanced performance across diverse applications. Through this Account, we aim to highlight the massive potential of TTF and its analogues-based porous crystals in chemistry and material science.
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Natural environments play a crucial role in transmission of antimicrobial resistance (AMR). Development of methods to manage antibiotic resistance genes (ARGs) in natural environments are usually limited to the laboratory or field scale, partially due to the complex dynamics of transmission between different environmental compartments. Here, we conducted a nine-year longitudinal profiling of ARGs at a watershed scale, and provide evidence that restrictions on livestock farms near water bodies significantly reduced riverine ARG abundance. Substantial reductions were revealed in the relative abundance of genes conferring resistance to aminoglycosides (42%), MLSB (36%), multidrug (55%), tetracyclines (53%), and other gene categories (59%). Additionally, improvements in water quality were observed, with distinct changes in concentrations of dissolved reactive phosphorus, ammonium, nitrite, pH, and dissolved oxygen. Antibiotic residues and other pharmaceuticals and personal care products (PPCPs) maintain at a similarly low level. Microbial source tracking demonstrates a significant decrease in swine fecal indicators, while human fecal pollution remains unchanged. These results suggest that the reduction in ARGs was due to a substantial reduction in input of antibiotic resistant bacteria and genes from animal excreta. Our findings highlight the watershed as a living laboratory for understanding the dynamics of AMR, and for evaluating the efficacy of environmental regulations, with implications for reducing environmental risks associated with AMR on a global scale.
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This paper shows a novel oxidative functionalization of α-amino ketones to yield the corresponding α-ketoamides and α-acylimidates. The reaction proceeds via oxygen delivery from water/alcohols in conjunction with an electron acceptor and 4-dimethylaminopyridine (DMAP). Mechanistic study indicates that DMAP exhibits a dual function of nucleophilic catalysis and proton abstraction.
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What is already known on this topic?: Smoking is the primary risk factor for a poor prognosis in chronic respiratory disease (CRD). Current tobacco surveillance efforts in China focus on the general population and do not adequately cover CRD patients. What is added by this report?: We employed electronic medical records (EMR) to track smoking habits in 28,334 hospitalized CRD patients at Beijing Chao-Yang Hospital. The rates of former and current smokers were 30.7% and 18.0%, respectively. Both former and current smokers exhibited an increased risk of respiratory symptoms and extended hospital stays. What are the implications for public health practice?: These results underscore the importance of implementing smoking monitoring and targeted cessation interventions for hospitalized patients with CRDs.
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This paper describes a mild and efficient catalytic deprotection method for isopropylidene ketals and benzylidene acetals using AcOH/H2O/DME(1,2-Dimethoxyethane). The method effectively removes ketal and acetal protecting groups from 2-deoxyglycosides which are prone to hydrolysis under acidic conditions. Moreover, it enables the selective removal of the terminal ketal over an internal one.
Subject(s)
Glycosides , Glycosides/chemistry , Glycosides/chemical synthesis , Water/chemistry , Stereoisomerism , Ketones/chemistry , Catalysis , Acetals/chemistry , Molecular StructureABSTRACT
INTRODUCTION: Accurate evaluation of exacerbation frequency is an essential part of COPD assessment. But relying on just the prior-year exacerbation history may not capture the full picture of risk given the inherent year-to-year fluctuations in exacerbation rates. This study aimed to evaluate the predictive performance of models incorporating the 3-year exacerbation history based on electronic medical record. MATERIALS AND METHODS: This retrospective cohort study included 86,501 COPD hospitalized patients in Beijing from 2008 to 2014. The annual frequency of COPD exacerbation hospitalizations over a 3-year period after the index hospitalization was calculated, with patients segmented into seven distinct exacerbation trajectory groups. Logistic regression was used to evaluate the predictive capability of the 3-year exacerbation history for exacerbation readmission in the fourth year. Predictors included age, sex, comorbidities, and exacerbation hospitalization in previous 1-3 years. Model performance was evaluated using area under the receiver operating characteristic curve (AUC). RESULTS: Of the studied patients, 56.5% were men, and the mean age (SD) was 73.8 (10.3) years. The overall readmission rate for COPD exacerbation was 0.31 per person-year, with only 3.8% of patients persistently readmitted over three consecutive years. The 3-year trajectory of exacerbation frequency was associated with exacerbation risk in the fourth year. Compared to just the prior year, the inclusion of a 3-year exacerbation hospitalization history notably improved prediction accuracy, with AUC elevating from 0.731 (0.724-0.739) to 0.786 (0.779-0.792). CONCLUSION: These results unveil the fluctuating nature of COPD exacerbation hospitalization frequency across years and demonstrate that integrating a more comprehensive 3-year exacerbation history significantly refines the prediction model for future risk, thus providing a more nuanced and actionable insight for clinical care.