Objective To investigate the therapeutic effect of folic acid combined with decitabine in diabetic retinop-athy(DR)mice with different methylenetetrahydrofolate reductase(MTHFR)genotypes.Methods The DR model mice were created by mating 20 MTHFR-/-mice with 20 wild-type C57 mice.A random number table method was employed to allocate 20 successfully modelled mice into the model group,DAC group,FA group,and FA+DAC group,with five mice assigned to each group.Five untreated MTHFR-/-and wild-type mice served as normal control.After constructing the DR model,the DAC group was injected intraperitoneally with 0.25 mg·kg-1 decitabine once every 5 days;the FA group was given 70 μg·kg-1 folic acid by tube feed once a day;the FA+DAC group was given 0.25 mg·kg-1 decitabine and 70μg·kg-1 folic acid at the same time;and the normal group was given an equal amount of physiological saline.All of the above groups were intervened for 30 days.OCT was employed for the measurement of retinal thickness,OCTA for retinal vascular density,histopathology(HE staining)for pathological changes in the mouse retina,real-time fluorescence quanti-tative PCR for mRNA expression,and Western blot analysis for protein expression levels.Results Compared with the wild-type model group,the degree of increase in retinal thickness and vascular density in the retinal layer was more pro-nounced in the MTHFR-/-mice model group(all P＜0.05).In wild-type mice,retinal thickness and retinal layer vessel den-sity were reduced in the DAC,FA and FA+DAC groups compared to the model group,with the FA+DAC group show-ing the greatest degree of reduction.The differences were all statistically significant(all P＜0.05);In MTHFR-/-mice,reti-nal thickness and vascular density in the retinal layer were reduced in the DAC group and the FA+DAC group compared to the model group(allP＜0.05).HE staining results showed an increased extent of retinal damage in the MTHFR-/-mice model group compared with the wild-type mice model group.Compared with the model group,the DAC group and the FA+DAC group had thinner retinas and more aligned ganglion cell layers in all types of mice,with the FA group having a worse effect and the FA+DAC group having a better treatment effect.The results of the polymerase chain reaction(PCR)revealed that the relative expression of the SAHH,MAT2A and DNMT1 proteins in the retinal tissues of the wildtype and MTHFR-/-mice model groups was elevated in comparison to the control group(all P＜0.05).Furthermore,the relative mR-NA expression of the DAC,FA and FA+DAC groups was reduced in comparison to the model group(all P＜0.05).In wild-type mice,the relative expression of MTHFR protein mRNA was decreased in the model group compared with the con-trol group,and increased in the DAC group,FA group,and FA+DAC group compared with the model group(all P＜0.05).Western blot results showed that the relative expression of DNMT1,MAT2A and SAHH proteins in the retinal tissues of the wild-type and MTHFR-/-mice model groups was higher than that of the control group(all P＜0.05),and the relative expression was lower in the DAC,FA,and FA+DAC groups compared with that in the model group(all P＜0.05).In wild-type mice,the relative expression of MTHFR protein in the retinal tissue of the model group was lower than that of the control group,and the relative expression of MTHFR protein in the FA group and the FA+DAC group was elevated com-pared with that of the model group(all P＜0.05).Conclusion The protective effect of folic acid combined with decit-abine on DR was superior to that of decitabine alone;treatment with folic acid in combination with decitabine may have yielded better efficacy in wild-type DR mice.

Objective:To investigate the characteristics of the nasal cycle and the patterns of bilateral nasal airflow distribution in patients with obstructive sleep apnea (OSA).Methods:This cross-sectional study analyzed data from 29 healthy subjects (control group: 16 males, 13 females; age range 23-60 years, mean 31.03±8.67 years) and 41 patients with OSA (OSA group: 34 males, 7 females; age range 20-62 years, mean 39.73±11.27 years) who visited the Sleep Medicine Center of Beijing Tongren Hospital, Capital Medical University, between March 2022 and April 2025. Whole-night split-channel nasal airflow and polysomnography were performed to calculate nasal airflow laterality, nasal cycle duration, and the effects of severity, sleep stages, and body position on bilateral nasal airflow distribution during sleep were analyzed.Results:The nasal cycle duration in OSA patients was significantly shorter than in controls (179.5 min vs. 312.5 min, χ 2=14.01, P<0.001). Apnea-hypopnea index (AHI) and age were independent influencing factors. In the OSA group, the incidence of nasal cycle transitions within 10 minutes after wake [(observed)7/50 vs. 2/55(expected), χ 2=14.32, P<0.001], REM sleep [(observed)23/34 vs. 14/43(expected), χ 2=8.14, P=0.004], and position changes (21/36 vs. 11/46, χ 2=12.02, P<0.001) was higher, while, in the control group, it was only associated with REM sleep (15/15 vs. 8/22, χ 2=8.80, P=0.003). Nasal airflow lateralization in the OSA group showed a stronger correlation with body position. The nasal airflow lateralization in the supine position was significantly lower in OSA patients than in controls [REM stage: 0.626 (0.425, 0.743) vs. 0.781 (0.706, 0.857), Z=3.62, P<0.001; N3 stage: 0.526 (0.438, 0.600) vs. 0.716 (0.608, 0.853), Z=2.17, P=0.032; N1/2 stage: 0.702 (0.526, 0.787) vs. 0.747 (0.663, 0.820), Z=1.68, P=0.095]. Multiple linear regression revealed that AHI explained 31.3% of the variance in nasal airflow lateralization during supine REM sleep. Conclusions:The nasal airflow regulation during sleep in OSA patients differs from that in healthy individuals. Compared with healthy subjects, OSA patients exhibit shorter nasal cycle durations, reduced nasal airflow lateralization in the supine position, and a higher likelihood of nasal cycle transitions triggered by position changes or arousal. Healthy subjects demonstrate high and stable nasal airflow asymmetry during sleep, with minimal influence from sleep stages or body position.

Purpose To evaluate the diagnostic value of an abbreviated protocol MRI(AP-MRI)based on first post-contrast subtracted(FAST)images for breast cancer detection.Materials and Methods This study included imaging data from 160 female patients with solid breast lesions who underwent breast MRI in the First Affiliated Hospital of Henan University of Chinese Medicine from April 2021 to January 2024.Two AP-MRI protocols were extracted from the full diagnostic protocol(FDP),including:dynamic contrast-enhanced MRI(DCE-MRI)A protocol:FAST and maximum-intensity projection(MIP)images,and DCE-MRI B protocol:FAST+MIP+diffusion-weighted imaging(DWI).Lesions categorized as breast imaging reporting and data system(BI-RADS)1-3 were classified as negative,and those categorized as BI-RADS 4-5 were classified as positive.Pathological findings served as the diagnostic gold standard.Two radiologists independently evaluated the lesions as negative/positive and compared with the gold standard.The sensitivity,specificity and accuracy of the three protocols were compared.Receiver operating characteristic curves were generated for each protocol,and the area under the curve(AUC)was compared.Results The accuracy of the three protocols showed statistically significant differences(Cochran's Qreader1=6.000,P=0.050;Cochran's Qreader2=10.909,P=0.012).The accuracy of the DCE-MRI A protocol was significantly lower than that of the FDP protocol(Z=2.449,Preader1=0.043;Z=2.858,Preader2=0.013).There were no statistically significant differences in sensitivity(Cochran's Qreader1=3.000,P=0.223;Cochran's Qreader2=2.667,P=0.264)or specificity(Cochran's Qreader1=3.000,P=0.223;Cochran's Qreader2=2.800,P=0.247)between the two AP-MRI protocols and the FDP protocol.There were no statistically significant differences in AUC between the DCE-MRI B protocol and the FDP protocol(Z=1.390-1.719,all P>0.05),while the AUC of the DCE-MRI A protocol had lower AUCs than the FDP protocol(Z=1.980,2.441;both P<0.05).Conclusion The AP-MRI protocol combining FAST,MIP and DWI shows diagnostic accuracy comparable to that of the FDP and greatly saves time and cost,suggesting its potential as an alternative imaging strategy for women with dense breasts and as a new diagnostic approach for high-risk populations.

Objective To develop and validate a nomogram model for predicting recurrence after radiofre-quency catheter ablation(RFCA)in patients with atrial fibrillation and heart failure using body surface electrocar-diogram indicators and clinical indicators.Methods We retrospectively analyzed 305 patients with atrial fibrilla-tion complicated with heart failure who underwent RFCA from January 2019 to January 2024.Patients were random-ized into training set(213 cases)and validation set(92 cases)at a ratio of 7:3 and followed up for at least 1 year.Based on the recurrence status,the patients were divided into recurrence group and non-recurrence group,with body surface electrocardiogram indicators and clinical indicators collected.Multivariate logistic regression analysis identified for risk factors for post RFCA recurrence,which were used to construct a nomogram.Model performance was assessed using the area under the receiver operating characteristic curve(AUC),Hosmer-Lemeshow test,calibration curves,and decision curve analysis(DCA).Results Among the 305 patients,84(27.54％)experi-enced recurrence after treatment.In the training set,61 patients had recurrence and 152 did not.No statistical differences were observed between the training set and the validation set(all P>0.05).In the training set,the recurrence group exhibited a higher proportion of persistent atrial fibrillation and significantly higher CHA2DS2-VASc scores,larger left atrial diameter,longer PR interval,and higher levels of NLR and NT-proBNP compared to the non-recurrence group(all P<0.05).Multivariate stepwise regression analysis revealed that high CHA2DS2-VASc score,long left atrial diameter,prolonged PR interval,and high NLR were independent risk factors of recurrence after RFCA(P<0.05)A four-factor prediction model was established as:Ln(P/1-P)=-12.87+0.84*CHA2DS2-VASc score+0.11* left atrial diameter+0.03*PR interval+0.31*NLR.The training and validation models showed AUCs of 0.85(95％CI:0.80～0.91)and 0.85(95％CI:0.76～0.94),respectively,suggesting that the model had good predictive efficiency.Hosmer-Lemeshow test results(χ2=2.43,P=0.965 for the training set;χ2=5.30,P=0.725 for the validation set)confirmed model fit,indicating that the fitted probability value was consistent with the actual probability value.Calibration curves after 1 000 times of Bootstrap repeated sampling showed the bias calibration curves of the training set and the validation set had good consistency with the actual curves,both close to the ideal curve.DCA revealed clinical utility across a wide threshold probability range(0.02～1.0 for the training set;0.04～1.0 for the validation set).Conclusion This nomogram,based on body surface electrocardiogram indicators and clinical indicators,effectively predicts post-RFCA recurrence in atrial fibrillation and heart failure patients,offering a useful tool for early assessment of recurrence risk.

Objective:To investigate the relationship between nerve growth factor (NGF) concentration in follicular fluid and abnormal menstrual cycle in infertile patients with polycystic ovary syndrome (PCOS).Methods:A retrospective cohort study was conducted on 100 infertile patients with PCOS who underwent in vitro fertilization and embryo transfer (IVF-ET) at Department of Obstetrics and Gynecology, Peking University Third Hospital from March 2017 to June 2019. For comparison, the 100 patients with PCOS were divided into low NGF group ( n=50) and high NGF group ( n=50) based on the median NGF concentration (1 644.03 ng/L) in follicular fluid. Baseline characteristics, menstrual status and clinical outcomes of assisted reproductive technology were compared. We performed multiple linear regression analysis to examine the effect of NGF in follicular fluid on menstrual cycle length for multivariate analysis. Results:1) PCOS patients in the low NGF group had significantly higher body mass index [(27.24±5.17) kg/m 2] and white blood cell count [7.31(5.99, 8.43)×10 9/L ] than those in the high NGF group [(25.03±4.46) kg/m 2, P=0.024; 5.95(5.08,7.01)×10 9/L, P=0.001], while high-density lipoprotein cholesterol [1.15 (0.98, 1.36) mmol/L] and basic follicle-stimulating hormone level [6.51 (5.10,7.95) U/L] in the low NGF group were significantly lower than those in the high NGF group [1.36 (1.09,1.52) mmol/L, P=0.039;6.51 (5.10,7.95)U/L, P=0.040]. 2) PCOS patients in the low NGF group had significantly higher menstrual cycle length [60.00 (35.00, 180.00) d] than the high NGF group [32.50 (27.00,67.50) d, P=0.001]. 3) Multiple linear regression analysis revealed that after adjustment for body mass index, age, infertility duration, infertility type, and glucose and lipid metabolic parameters, the NGF concentration in the follicular fluid independently and negatively correlated with menstrual cycle length ( P<0.05). 4) The NGF concentration in follicular fluid was not correlated with assisted reproductive outcomes. Conclusion:NGF concentration in follicular fluid is closely related to the degree of menstrual cycle abnormalities in patients with PCOS.

Objective:To investigate the relationship between nerve growth factor (NGF) concentration in follicular fluid and abnormal menstrual cycle in infertile patients with polycystic ovary syndrome (PCOS).Methods:A retrospective cohort study was conducted on 100 infertile patients with PCOS who underwent in vitro fertilization and embryo transfer (IVF-ET) at Department of Obstetrics and Gynecology, Peking University Third Hospital from March 2017 to June 2019. For comparison, the 100 patients with PCOS were divided into low NGF group ( n=50) and high NGF group ( n=50) based on the median NGF concentration (1 644.03 ng/L) in follicular fluid. Baseline characteristics, menstrual status and clinical outcomes of assisted reproductive technology were compared. We performed multiple linear regression analysis to examine the effect of NGF in follicular fluid on menstrual cycle length for multivariate analysis. Results:1) PCOS patients in the low NGF group had significantly higher body mass index [(27.24±5.17) kg/m 2] and white blood cell count [7.31(5.99, 8.43)×10 9/L ] than those in the high NGF group [(25.03±4.46) kg/m 2, P=0.024; 5.95(5.08,7.01)×10 9/L, P=0.001], while high-density lipoprotein cholesterol [1.15 (0.98, 1.36) mmol/L] and basic follicle-stimulating hormone level [6.51 (5.10,7.95) U/L] in the low NGF group were significantly lower than those in the high NGF group [1.36 (1.09,1.52) mmol/L, P=0.039;6.51 (5.10,7.95)U/L, P=0.040]. 2) PCOS patients in the low NGF group had significantly higher menstrual cycle length [60.00 (35.00, 180.00) d] than the high NGF group [32.50 (27.00,67.50) d, P=0.001]. 3) Multiple linear regression analysis revealed that after adjustment for body mass index, age, infertility duration, infertility type, and glucose and lipid metabolic parameters, the NGF concentration in the follicular fluid independently and negatively correlated with menstrual cycle length ( P<0.05). 4) The NGF concentration in follicular fluid was not correlated with assisted reproductive outcomes. Conclusion:NGF concentration in follicular fluid is closely related to the degree of menstrual cycle abnormalities in patients with PCOS.

Objective To investigate the therapeutic effect of folic acid combined with decitabine in diabetic retinop-athy(DR)mice with different methylenetetrahydrofolate reductase(MTHFR)genotypes.Methods The DR model mice were created by mating 20 MTHFR-/-mice with 20 wild-type C57 mice.A random number table method was employed to allocate 20 successfully modelled mice into the model group,DAC group,FA group,and FA+DAC group,with five mice assigned to each group.Five untreated MTHFR-/-and wild-type mice served as normal control.After constructing the DR model,the DAC group was injected intraperitoneally with 0.25 mg·kg-1 decitabine once every 5 days;the FA group was given 70 μg·kg-1 folic acid by tube feed once a day;the FA+DAC group was given 0.25 mg·kg-1 decitabine and 70μg·kg-1 folic acid at the same time;and the normal group was given an equal amount of physiological saline.All of the above groups were intervened for 30 days.OCT was employed for the measurement of retinal thickness,OCTA for retinal vascular density,histopathology(HE staining)for pathological changes in the mouse retina,real-time fluorescence quanti-tative PCR for mRNA expression,and Western blot analysis for protein expression levels.Results Compared with the wild-type model group,the degree of increase in retinal thickness and vascular density in the retinal layer was more pro-nounced in the MTHFR-/-mice model group(all P＜0.05).In wild-type mice,retinal thickness and retinal layer vessel den-sity were reduced in the DAC,FA and FA+DAC groups compared to the model group,with the FA+DAC group show-ing the greatest degree of reduction.The differences were all statistically significant(all P＜0.05);In MTHFR-/-mice,reti-nal thickness and vascular density in the retinal layer were reduced in the DAC group and the FA+DAC group compared to the model group(allP＜0.05).HE staining results showed an increased extent of retinal damage in the MTHFR-/-mice model group compared with the wild-type mice model group.Compared with the model group,the DAC group and the FA+DAC group had thinner retinas and more aligned ganglion cell layers in all types of mice,with the FA group having a worse effect and the FA+DAC group having a better treatment effect.The results of the polymerase chain reaction(PCR)revealed that the relative expression of the SAHH,MAT2A and DNMT1 proteins in the retinal tissues of the wildtype and MTHFR-/-mice model groups was elevated in comparison to the control group(all P＜0.05).Furthermore,the relative mR-NA expression of the DAC,FA and FA+DAC groups was reduced in comparison to the model group(all P＜0.05).In wild-type mice,the relative expression of MTHFR protein mRNA was decreased in the model group compared with the con-trol group,and increased in the DAC group,FA group,and FA+DAC group compared with the model group(all P＜0.05).Western blot results showed that the relative expression of DNMT1,MAT2A and SAHH proteins in the retinal tissues of the wild-type and MTHFR-/-mice model groups was higher than that of the control group(all P＜0.05),and the relative expression was lower in the DAC,FA,and FA+DAC groups compared with that in the model group(all P＜0.05).In wild-type mice,the relative expression of MTHFR protein in the retinal tissue of the model group was lower than that of the control group,and the relative expression of MTHFR protein in the FA group and the FA+DAC group was elevated com-pared with that of the model group(all P＜0.05).Conclusion The protective effect of folic acid combined with decit-abine on DR was superior to that of decitabine alone;treatment with folic acid in combination with decitabine may have yielded better efficacy in wild-type DR mice.

Objective To develop and validate a nomogram model for predicting recurrence after radiofre-quency catheter ablation(RFCA)in patients with atrial fibrillation and heart failure using body surface electrocar-diogram indicators and clinical indicators.Methods We retrospectively analyzed 305 patients with atrial fibrilla-tion complicated with heart failure who underwent RFCA from January 2019 to January 2024.Patients were random-ized into training set(213 cases)and validation set(92 cases)at a ratio of 7:3 and followed up for at least 1 year.Based on the recurrence status,the patients were divided into recurrence group and non-recurrence group,with body surface electrocardiogram indicators and clinical indicators collected.Multivariate logistic regression analysis identified for risk factors for post RFCA recurrence,which were used to construct a nomogram.Model performance was assessed using the area under the receiver operating characteristic curve(AUC),Hosmer-Lemeshow test,calibration curves,and decision curve analysis(DCA).Results Among the 305 patients,84(27.54％)experi-enced recurrence after treatment.In the training set,61 patients had recurrence and 152 did not.No statistical differences were observed between the training set and the validation set(all P>0.05).In the training set,the recurrence group exhibited a higher proportion of persistent atrial fibrillation and significantly higher CHA2DS2-VASc scores,larger left atrial diameter,longer PR interval,and higher levels of NLR and NT-proBNP compared to the non-recurrence group(all P<0.05).Multivariate stepwise regression analysis revealed that high CHA2DS2-VASc score,long left atrial diameter,prolonged PR interval,and high NLR were independent risk factors of recurrence after RFCA(P<0.05)A four-factor prediction model was established as:Ln(P/1-P)=-12.87+0.84*CHA2DS2-VASc score+0.11* left atrial diameter+0.03*PR interval+0.31*NLR.The training and validation models showed AUCs of 0.85(95％CI:0.80～0.91)and 0.85(95％CI:0.76～0.94),respectively,suggesting that the model had good predictive efficiency.Hosmer-Lemeshow test results(χ2=2.43,P=0.965 for the training set;χ2=5.30,P=0.725 for the validation set)confirmed model fit,indicating that the fitted probability value was consistent with the actual probability value.Calibration curves after 1 000 times of Bootstrap repeated sampling showed the bias calibration curves of the training set and the validation set had good consistency with the actual curves,both close to the ideal curve.DCA revealed clinical utility across a wide threshold probability range(0.02～1.0 for the training set;0.04～1.0 for the validation set).Conclusion This nomogram,based on body surface electrocardiogram indicators and clinical indicators,effectively predicts post-RFCA recurrence in atrial fibrillation and heart failure patients,offering a useful tool for early assessment of recurrence risk.

Purpose To evaluate the diagnostic value of an abbreviated protocol MRI(AP-MRI)based on first post-contrast subtracted(FAST)images for breast cancer detection.Materials and Methods This study included imaging data from 160 female patients with solid breast lesions who underwent breast MRI in the First Affiliated Hospital of Henan University of Chinese Medicine from April 2021 to January 2024.Two AP-MRI protocols were extracted from the full diagnostic protocol(FDP),including:dynamic contrast-enhanced MRI(DCE-MRI)A protocol:FAST and maximum-intensity projection(MIP)images,and DCE-MRI B protocol:FAST+MIP+diffusion-weighted imaging(DWI).Lesions categorized as breast imaging reporting and data system(BI-RADS)1-3 were classified as negative,and those categorized as BI-RADS 4-5 were classified as positive.Pathological findings served as the diagnostic gold standard.Two radiologists independently evaluated the lesions as negative/positive and compared with the gold standard.The sensitivity,specificity and accuracy of the three protocols were compared.Receiver operating characteristic curves were generated for each protocol,and the area under the curve(AUC)was compared.Results The accuracy of the three protocols showed statistically significant differences(Cochran's Qreader1=6.000,P=0.050;Cochran's Qreader2=10.909,P=0.012).The accuracy of the DCE-MRI A protocol was significantly lower than that of the FDP protocol(Z=2.449,Preader1=0.043;Z=2.858,Preader2=0.013).There were no statistically significant differences in sensitivity(Cochran's Qreader1=3.000,P=0.223;Cochran's Qreader2=2.667,P=0.264)or specificity(Cochran's Qreader1=3.000,P=0.223;Cochran's Qreader2=2.800,P=0.247)between the two AP-MRI protocols and the FDP protocol.There were no statistically significant differences in AUC between the DCE-MRI B protocol and the FDP protocol(Z=1.390-1.719,all P>0.05),while the AUC of the DCE-MRI A protocol had lower AUCs than the FDP protocol(Z=1.980,2.441;both P<0.05).Conclusion The AP-MRI protocol combining FAST,MIP and DWI shows diagnostic accuracy comparable to that of the FDP and greatly saves time and cost,suggesting its potential as an alternative imaging strategy for women with dense breasts and as a new diagnostic approach for high-risk populations.

Objective:To investigate the characteristics of the nasal cycle and the patterns of bilateral nasal airflow distribution in patients with obstructive sleep apnea (OSA).Methods:This cross-sectional study analyzed data from 29 healthy subjects (control group: 16 males, 13 females; age range 23-60 years, mean 31.03±8.67 years) and 41 patients with OSA (OSA group: 34 males, 7 females; age range 20-62 years, mean 39.73±11.27 years) who visited the Sleep Medicine Center of Beijing Tongren Hospital, Capital Medical University, between March 2022 and April 2025. Whole-night split-channel nasal airflow and polysomnography were performed to calculate nasal airflow laterality, nasal cycle duration, and the effects of severity, sleep stages, and body position on bilateral nasal airflow distribution during sleep were analyzed.Results:The nasal cycle duration in OSA patients was significantly shorter than in controls (179.5 min vs. 312.5 min, χ 2=14.01, P<0.001). Apnea-hypopnea index (AHI) and age were independent influencing factors. In the OSA group, the incidence of nasal cycle transitions within 10 minutes after wake [(observed)7/50 vs. 2/55(expected), χ 2=14.32, P<0.001], REM sleep [(observed)23/34 vs. 14/43(expected), χ 2=8.14, P=0.004], and position changes (21/36 vs. 11/46, χ 2=12.02, P<0.001) was higher, while, in the control group, it was only associated with REM sleep (15/15 vs. 8/22, χ 2=8.80, P=0.003). Nasal airflow lateralization in the OSA group showed a stronger correlation with body position. The nasal airflow lateralization in the supine position was significantly lower in OSA patients than in controls [REM stage: 0.626 (0.425, 0.743) vs. 0.781 (0.706, 0.857), Z=3.62, P<0.001; N3 stage: 0.526 (0.438, 0.600) vs. 0.716 (0.608, 0.853), Z=2.17, P=0.032; N1/2 stage: 0.702 (0.526, 0.787) vs. 0.747 (0.663, 0.820), Z=1.68, P=0.095]. Multiple linear regression revealed that AHI explained 31.3% of the variance in nasal airflow lateralization during supine REM sleep. Conclusions:The nasal airflow regulation during sleep in OSA patients differs from that in healthy individuals. Compared with healthy subjects, OSA patients exhibit shorter nasal cycle durations, reduced nasal airflow lateralization in the supine position, and a higher likelihood of nasal cycle transitions triggered by position changes or arousal. Healthy subjects demonstrate high and stable nasal airflow asymmetry during sleep, with minimal influence from sleep stages or body position.