The Association of High Arousal Threshold with Hypertension and Diabetes in Obstructive Sleep Apnea.

Objective: Compared to low arousal threshold (AT), high AT is an easily overlooked characteristic for obstructive sleep apnea (OSA) severity estimation. This study aims to evaluate the relationship between high AT, hypertension and diabetes in OSA, compared to those with apnea-hypopnea index (AHI). Methods: A total of 3400 adults diagnosed with OSA were retrospectively recruited. Propensity score matching (PSM) was conducted to further categorize these patients into the low and high AT groups based on the strategy established by previous literature. The different degrees of AHI and quantified AT (AT score) were subsequently measured. The correlation of AT and AHI with the occurrence of various comorbidities in OSA was estimated by logistic regression analysis with odds ratio (OR). Results: After PSM, 938 pairs of patients arose. The median AT score of high and low AT group was 21.7 and 12.2 scores, and the adjusted OR of high AT for hypertension and diabetes was 1.31 (95% CI = 1.07-1.62, P < 0.01) and 1.45 (95% CI = 1.01-2.08, P < 0.05), respectively. Compared to low AT score group, the OR significantly increased in patients with very high AT score (30 ≤ AT score), especially for diabetes (OR = 1.79, 95% CI = 1.02-3.13, P < 0.05). The significant association was not observed in AHI with increasing prevalent diabetes. Conclusion: Higher AT is significantly associated with increased prevalence of hypertension and diabetes in patients with OSA. Compared with AHI, AT score is a potentially comprehensive indicator for better evaluating the relationship between OSA and related comorbidities.

Application Value of Cardiometabolic Index for the Screening of Obstructive Sleep Apnea with or Without Metabolic Syndrome.

Background: Obstructive sleep apnea (OSA) is a common chronic disease with various comorbidities. The cardiometabolic index (CMI) reflects visceral fat tissue distribution and function, assessing the risk of obesity-related conditions such as metabolic syndrome (MetS) and stroke, which are strongly connected to OSA. The relationship between CMI with OSA and OSA combined with MetS (OMS) remains unclear. This study aims to evaluate the screening value of CMI for OSA and OMS, compared to the lipid accumulation product (LAP). Methods: A total of 280 participants who underwent polysomnography were finally included, with the measurements of metabolic-related laboratory test results such as total cholesterol and triglyceride. Receiver operating curve (ROC) analysis and calculation of the area under the curve (AUC) were conducted to assess the screening potential of CMI, LAP, and the logistic regression models established based on them for OSA and OMS. The Youden index, sensitivity, and specificity were used to determine the optimal cutoff points. Results: ROC curve analysis revealed that the AUCs for CMI in screening OSA and OMS were 0.808 and 0.797, and the optimal cutoff values were 0.71 (sensitivity 0.797, specificity 0.776) and 0.89 (sensitivity 0.830, specificity 0.662), respectively, showing higher Youden index than LAP. The AUCs of screening models based on CMI for OSA and OMS were 0.887 and 0.824, respectively. Conclusion: CMI and LAP can effectively screen for OSA and OMS, while CMI has more practical cutoff values for identifying the diseased states. Screening models based on CMI demonstrate a high discriminatory ability for OSA and OMS, which needs verification in a large-scale population.

Establishment and Application Evaluation of an Improved Obstructive Sleep Apnea Screening Questionnaire for Chinese Community: The CNCQ-OSA.

Objective: Obstructive sleep apnea (OSA) is a common sleep-disordered breathing disease. We aimed to establish an improved screening questionnaire without physical examinations for OSA named the CNCQ-OSA (Chinese community questionnaire for OSA). Methods: A total of 2585 participants who visited sleep medicine center and underwent overnight polysomnography were grouped into two independent cohorts: derivation (n = 2180) and validation (n = 405). The CNCQ-OSA was designed according to the baseline of patients in derivation cohort. We comprehensively analyzed the data to evaluate the predictive value of the CNCQ-OSA, compared to the GOAL questionnaire, STOP-Bang questionnaire (SBQ) and NoSAS questionnaire. Results: The CNCQ-OSA included seven variables: loud snoring, BMI ≥ 25 kg/m2, male gender, apnea, sleepiness, hypertension and age ≥30, with a total score ranging from 7 to 16.7 points (≥13.5 points indicating high risk of OSA, ≥14.5 points indicating extremely high risk). In the derivation and validation cohorts, the areas under the curve of the CNCQ-OSA were 0.761 and 0.767, respectively. In the validation cohort, the sensitivity and specificity of a CNCQ-OSA score ≥13.5 points for the apnea-hypopnea index (AHI) ≥5/h were 0.821 and 0.559, respectively (Youden index, 0.380), and the score ≥14.5 points were 0.494 and 0.887, respectively (Youden index, 0.375). The CNCQ-OSA had a better predictive value for AHI ≥ 5/h, AHI > 15/h and AHI > 30/h, with the highest Youden index, compared to the other questionnaires. Conclusion: The CNCQ-OSA can effectively identify the risk of OSA, which is appropriate for self-screening at home without physical examinations.

In-Situ Welding Carbon Nanotubes into a Porous Solid with Super-High Compressive Strength and Fatigue Resistance.

Carbon nanotube (CNT) and graphene-based sponges and aerogels have an isotropic porous structure and their mechanical strength and stability are relatively lower. Here, we present a junction-welding approach to fabricate porous CNT solids in which all CNTs are coated and welded in situ by an amorphous carbon layer, forming an integral three-dimensional scaffold with fixed joints. The resulting CNT solids are robust, yet still highly porous and compressible, with compressive strengths up to 72 MPa, flexural strengths up to 33 MPa, and fatigue resistance (recovery after 100,000 large-strain compression cycles at high frequency). Significant enhancement of mechanical properties is attributed to the welding-induced interconnection and reinforcement of structural units, and synergistic effects stemming from the core-shell microstructures consisting of a flexible CNT framework and a rigid amorphous carbon shell. Our results provide a simple and effective method to manufacture high-strength porous materials by nanoscale welding.

Three-dimensional carbon nanotube sponge-array architectures with high energy dissipation.

Carbon nanotube sponges and aligned arrays are seamlessly integrated into numerous possible configurations such as series, parallel, package, and sandwich complex structures, leading to significantly broadened stress plateau and enhanced energy dissipation.

Integrated random-aligned carbon nanotube layers: deformation mechanism under compression.

Carbon nanotubes have the potential to construct highly compressible and elastic macroscopic structures such as films, aerogels and sponges. The structure-related deformation mechanism determines the mechanical behavior of those structures and niche applications. Here, we show a novel strategy to integrate aligned and random nanotube layers and reveal their deformation mechanism under uniaxial compression with a large range of strain and cyclic testing. Integrated nanotube layers deform sequentially with different mechanisms due to the distinct morphology of each layer. While the aligned layer forms buckles under compression, nanotubes in the random layer tend to be parallel and form bundles, resulting in the integration of quite different properties (strength and stiffness) and correspondingly distinct plateau regions in the stress-strain curves. Our results indicate a great promise of constructing hierarchical carbon nanotube structures with tailored energy absorption properties, for applications such as cushioning and buffering layers in microelectromechanical systems.

Magnetic and highly recyclable macroporous carbon nanotubes for spilled oil sorption and separation.

Development of sorbent materials with high selectivity and sorption capacity, easy collection and recyclability is demanding for spilled oil recovery. Although many sorption materials have been proposed, a systematic study on how they can be reused and possible performance degradation during regeneration remains absent. Here we report magnetic carbon nanotube sponges (Me-CNT sponge), which are porous structures consisting of interconnected CNTs with rich Fe encapsulation. The Me-CNT sponges show high mass sorption capacity for diesel oil reached 56 g/g, corresponding to a volume sorption capacity of 99%. The sponges are mechanically strong and oil can be squeezed out by compression. They can be recycled using through reclamation by magnetic force and desorption by simple heat treatment. The Me-CNT sponges maintain original structure, high capacity, and selectivity after 1000 sorption and reclamation cycles. Our results suggest that practical application of CNT macrostructures in the field of spilled oil recovery is feasible.