Nitrogen oxides(NOx=NO+NO2)are important precursors of ozone(O3),and NOx and its oxides together constitute reactive nitrogen oxides(NOy)in the atmosphere.A comprehensive understanding of the total NOy level in the atmosphere is of great significance for a deeper understanding of the atmospheric nitrogen cycle and oxidation,as well as for formulating strategies for air pollution prevention and control.In this work,a thermal decomposition-broadband cavity enhanced absorption spectroscopy(TD-BBCEAS)technique for online measurement of total NOy in the atmosphere was developed.With this method,the NOy was efficiently converted into NO2,and the total NOy concentration in the atmosphere was indirectly obtained by measuring NO2.Focusing on the key factors affecting the measurement of total NOy,the influence of NO titration efficiency and other NOy component TD efficiency on measurement accuracy was emphasized.By changing the oxygen(O2)flow rate through the mercury lamp to alter the O3 concentration for titrating NO,the conversion efficiency of NO was evaluated.At O2 flow rate of 6 mL/min,the conversion efficiency of NO was greater than 99%.TD efficiency testing and analysis on NO2,peroxyacetyl nitrate(PAN),nitric acid(HNO3),and nitrous acid(HONO),which account for a large proportion of atmospheric NOy components,was carried out using 680℃as the optimal TD temperature for efficient conversion of NOy.With NO and HONO sample gases as typical verification gases,the conversion efficiency of NOy and the accuracy of NOy measurement by TD-BBCEAS system were verified by switching the on and off modes of mercury lamp and TD device.At integration time of 60 s,the detection limit of the system for NOy was 2.83×1010 molecules/cm3(60 s,2σ).A comparative measurement of actual atmospheric NOy was conducted between the TD-BBCEAS system and the NOy analyzer.The observation results showed a correlation coefficient(R2)of 0.98 and a slope of 0.93,further verifying the feasibility and accuracy of applying the TD-BBCEAS system to measurement of total NOy.

Objective To investigate the impact of aortic valve calcification on ascending aortic elasticity.Methods A total of 103 patients with aortic valve calcification indicated by coronary computed tomography angiography(CCTA)(calcification group),and 101 patients without aortic valve calcification(non calcification group)were selected.The calcification group was subdivided into group A,group B,and group C based on the number of calcified leaflets.The original data was automatically reconstructed at 5％R-R intervals throughout the cardiac cycle.Cross-sectional area and diameter of the ascending aorta were measured at 45 mm above the annulus,and four ascending aortic elasticity indicators aortic(％A),aortic distensibility(AD),aortic compliance(AC)and aortic stiffness index(ASI)were calculated.Agatston method was used to calculate the aortic valve calcification score.The effect of aortic valve calcification on the elasticity of the ascending aortic and its correlation were analyzed.Results The％A,AD,and AC of the calcification group were lower than those of the non calcification group,but the ASI was higher than that of the non calcification group,the difference was statistically significant(P＜0.05).The number of calcified leaflets affected ascending aortic elasticity,with comparisons between groups A and B,the difference was no statistically significant(P＞0.05),groups A and C,and groups B and C,the difference was statistically significant(P＜0.05).Calcification score was negatively correlated with％A,AD,and AC,and positively correlated with ASI.Conclusion Aortic valve calcification can affect the elasticity of the ascending aortic,and more than two calcified leaflets have more significant effects on the elasticity of the ascending aortic.

OBJECTIVE: To investigate the risk factors associated with the development of knee osteoarthritis (OA) following arthroscopic surgery for degenerative lesions of the posterior horn of the medial meniscus. METHODS: Between January 2012 and January 2014, a retrospective analysis was conducted on 506 patients who underwent arthroscopic surgery for degenerative disease of the posterior horn of the medial meniscus. The cohort included 230 males and 276 females, aged from 32 to 58 years old with an average of (46.77±9.02) years old. According to the results of postoperative follow-up, patients were categorized into a knee osteoarthritis(OA) group and a non-OA group. The following parameters were recorded for each subject:gender, medial proximal tibial angle (MPTA), hip-knee-ankle angle (HKA), presence of bone edema on MRI, physical characteristics (including McMurray test results, locking symptoms, and medial knee tenderness points), meniscus protrusion, type of meniscus injury, and free body condition as observed via arthroscopy. Multivariate unconditional Logistic regression analysis was employed to investigate the associated factors influencing the 10-year postoperative incidence of knee osteoarthritis following surgery for degenerative injury of the posterior horn of the medial meniscus. Independent risk factors potentially influencing the development of postoperative OA were identified, and a nomogram-based predictive model for postoperative OA was established. The discriminatory ability and calibration accuracy of the model were assessed using the C-index and Hosmer-Lemeshow goodness-of-fit test, respectively. Furthermore, internal validation was performed using the bootstrap resampling method. RESULTS: Within a 10-year period following arthroscopic surgery, there were 123 patients in the OA group and 383 patients in the non-OA group. Significant differences were observed between two groups with respect to gender (χ²=5.156, P=0.023), MPTA<86.6° (χ²=21.671, P<0.001), varus lower limb alignment( χ²= 80.086, P<0.001). Additionally, meniscus extrusion (χ²=6.371, P=0.012), meniscus transverse tear (χ²=14.573, P<0.001), and bone edema detected on MRI(χ²=9.881, P=0.002) were identified as factors associated with the development of postoperative knee OA. The multifactorial Logistic regression analysis revealed that the lower limb line of force inversion OR=4.324, 95%CI (1.391, 13.443), P=0.011;MPTA <86.6°, OR=2.519, 95%CI (1.150, 5.519), P=0.021;transverse meniscus tear, OR=4.546, 95%CI (1.827, 11.310), P=0.001;meniscus ectropion, OR=5.401, 95%CI (1.992, 14.646), P=0.001;and bone edema manifestation on MRI OR=2.692, 95%CI (1.169, 6.200), P=0.020. They were independent risk factors associated with the development of postoperative OA. The area under the ROC curve predicted by the model was 0.927, 95%CI (0.903, 0.950). The Hosmer-Lemeshow goodness-of-fit test, used to evaluate the accuracy of the model, yielded P=0.689. Additionally, the internally sampled calibration curve demonstrated good consistency with the actual postoperative OA outcomes. CONCLUSION Varus alignment of the lower extremity, MPTA <86.6°, transverse meniscus tear, lateral meniscus injury, and bone marrow edema observed on MRI were independent risk factors for the development of knee osteoarthritis following arthroscopic surgery. Additionally, the prognostic model demonstrated excellent predictive performance.
Humans ; Male ; Female ; Middle Aged ; Arthroscopy/adverse effects* ; Adult ; Retrospective Studies ; Tibial Meniscus Injuries/surgery* ; Osteoarthritis, Knee/epidemiology* ; Risk Factors ; Menisci, Tibial/surgery* ; Incidence ; Postoperative Complications/epidemiology*

Septic shock, a prevalent critical condition in intensive care units (ICU) and a major cause of patient mortality, is fundamentally attributed to microcirculatory dysfunction. Traditional macrocirculatory parameters are often insufficiently sensitive to reflect microcirculatory status. Consequently monitoring peripheral microcirculatory function holds crucial significance for assessing disease progression and evaluating therapeutic efficacy in septic shock. The peripheral perfusion index (PPI), obtained from a standard pulse oximeter, is based on photoplethysmography (PPG). It calculates the differential absorption of red and infrared light emitted by the sensor between pulsatile arterial blood and non-pulsatile tissue, enabling real-time reflection of peripheral perfusion and thus providing non-invasive, continuous monitoring of microcirculatory function. Although often overlooked compared to other ICU monitoring parameters, PPI has demonstrated notable clinical advances in septic shock management. Specifically, in early identification, PPI combined with sequential organ failure assessment (SOFA) predicts disease progression, with its dynamic changes further aiding prognosis assessment. During fluid resuscitation, it guides fluid responsiveness evaluation and serves as a therapeutic target to optimize strategies. In circulatory support, it assists in determining vasoactive drug initiation timing and dosage titration. Additionally, PPI aids mechanical ventilation weaning and organ dysfunction evaluation. This article reviews the principles, influencing factors, and clinical application advances of PPI in septic shock, aiming to provide clinicians with a basis for individualized intervention, improved patient outcomes, and the advancement of precision medicine in septic shock management.
Humans ; Shock, Septic/therapy* ; Microcirculation ; Perfusion Index ; Prognosis ; Photoplethysmography

Objective To assess the efficacy of a novel inguinal tourniquet in healthy individuals and to investigate the relationship between localized inguinal compression and femoral artery blood flow occlusion.Methods A self-controlled study was conducted.From November 9 to November 30,2024,11 volunteers were recruited at the Third Medical Center of Chinese PLA General Hospital.Three compression methods--finger pressure,a novel groin tourniquet,and a SAM junction tourniquet(SJT)—were applied bilaterally to the inguinal region until distal blood flow signals disappeared.Each compression method was tested in 22 trials with a 5-minute interval between operations.Differences in hemostatic efficacy between bilateral inguinal regions and across compression methods were compared.Subsequently,the novel tourniquet was incrementally pressurized in 120 mmHg multiples using an integrated pressure device to analyze trends in popliteal artery blood flow velocity.Observational indicators included the internal pressure of the tourniquet pressurization device,peak systolic velocity(PSV)of popliteal artery,inguinal surface pressure magnitude,inguinal surface pressure distribution,and pain scores(assessed using a single-dimensional numerical rating scale).Results No statistically significant difference was observed in the minimum pressure required to occlude femoral artery blood flow bilaterally(P>0.05).The success rates of femoral artery blood flow occlusion at the inguinal region were 100%for the novel inguinal tourniquet,SJT,and finger pressure.The novel inguinal tourniquet induced the highest pain scores,ranging from 5 to 8.A significant reduction in PSV of popliteal artery was noted when the intra-tourniquet pressure reached 360 mmHg and 480 mmHg(P<0.05),with a 95%hemostasis efficacy observed within the range of 360-600 mmHg.No significant association was observed between the recovery of popliteal artery blood flow after limb movement and inguinal pressure distribution(P>0.05).The PSV of popliteal artery exhibited the strongest negative correlation with the average pressure within the inguinal compression area(r=-0.79,P<0.001),with a linear regression fitting line of y=69.69-0.13x(P<0.001,R2=0.58).Conclusions The novel inguinal tourniquet effectively occludes femoral artery blood flow within a pressure range of 360-600 mmHg,accompanied by moderate-to-severe pain.Its hemostatic mechanism mainly relies on increasing the mean pressure within the inguinal compression area.

Aim To investigate the effects of SAHA on the expression of P-gp and the pharmacokinetic pa-rameters of its substrate phenytoin sodium in rats under hypoxic environments.Methods Wistar rats were randomly divided into the normioxic group,the hypoxic model group,and the low-,medium-and high-dose vorinostat(SAHA)groups.Liver tissues were col-lected,and the expression levels of P-gp and HDAC5 were detected by Real-time PCR and Western blot.The morphological changes of liver tissues were ob-served by HE staining.Following intragastric adminis-tration of 50 mg·kg-1 phenytoin sodium to each group,blood samples were collected,and the plasma concentration of phenytoin sodium was determined u-sing UFLC-MS/MS to calculate pharmacokinetic pa-rameters.Results Compared with the normoxic group,the expression of HDAC5 in the liver tissues of hypoxia model rats increased,while the expression of P-gp decreased.After SAHA treatment,HDAC5 expression decreased,and P-gp expression increased.Among the SAHA groups,the medium-dose group showed the most significant effect,and HE staining re-sults indicated that this concentration did not cause damage to rat liver tissues.Compared with the normox-ic group,the AUC,Cmax,and T1/2 of phenytoin sodium in hypoxia model rats were significantly raised.After administration of the medium dose of SAHA,the AUC,Cmax,MRT,and T1/2 were significantly reduced,while CLZ/r was significantly increased.Conclusions Un-der hypoxic environments,the expression of P-gp in rat liver tissue is significantly downregulated,leading to increased systemic exposure of phenytoin,reduced clearance,and consequently elevated blood concentra-tions,raising the risk of central nervous system toxici-ty.In contrast,SAHA suppresses HDAC5 expression,thereby activating P-gp transcription and enhancing its efflux function.This results in decreased systemic ex-posure and improved clearance of phenytoin,signifi-cantly reducing drug accumulation in body and ulti-mately lowering the risk of adverse effects.

Aim To investigate the effects of SAHA on the expression of P-gp and the pharmacokinetic pa-rameters of its substrate phenytoin sodium in rats under hypoxic environments.Methods Wistar rats were randomly divided into the normioxic group,the hypoxic model group,and the low-,medium-and high-dose vorinostat(SAHA)groups.Liver tissues were col-lected,and the expression levels of P-gp and HDAC5 were detected by Real-time PCR and Western blot.The morphological changes of liver tissues were ob-served by HE staining.Following intragastric adminis-tration of 50 mg·kg-1 phenytoin sodium to each group,blood samples were collected,and the plasma concentration of phenytoin sodium was determined u-sing UFLC-MS/MS to calculate pharmacokinetic pa-rameters.Results Compared with the normoxic group,the expression of HDAC5 in the liver tissues of hypoxia model rats increased,while the expression of P-gp decreased.After SAHA treatment,HDAC5 expression decreased,and P-gp expression increased.Among the SAHA groups,the medium-dose group showed the most significant effect,and HE staining re-sults indicated that this concentration did not cause damage to rat liver tissues.Compared with the normox-ic group,the AUC,Cmax,and T1/2 of phenytoin sodium in hypoxia model rats were significantly raised.After administration of the medium dose of SAHA,the AUC,Cmax,MRT,and T1/2 were significantly reduced,while CLZ/r was significantly increased.Conclusions Un-der hypoxic environments,the expression of P-gp in rat liver tissue is significantly downregulated,leading to increased systemic exposure of phenytoin,reduced clearance,and consequently elevated blood concentra-tions,raising the risk of central nervous system toxici-ty.In contrast,SAHA suppresses HDAC5 expression,thereby activating P-gp transcription and enhancing its efflux function.This results in decreased systemic ex-posure and improved clearance of phenytoin,signifi-cantly reducing drug accumulation in body and ulti-mately lowering the risk of adverse effects.

Objective To investigate the impact of aortic valve calcification on ascending aortic elasticity.Methods A total of 103 patients with aortic valve calcification indicated by coronary computed tomography angiography(CCTA)(calcification group),and 101 patients without aortic valve calcification(non calcification group)were selected.The calcification group was subdivided into group A,group B,and group C based on the number of calcified leaflets.The original data was automatically reconstructed at 5％R-R intervals throughout the cardiac cycle.Cross-sectional area and diameter of the ascending aorta were measured at 45 mm above the annulus,and four ascending aortic elasticity indicators aortic(％A),aortic distensibility(AD),aortic compliance(AC)and aortic stiffness index(ASI)were calculated.Agatston method was used to calculate the aortic valve calcification score.The effect of aortic valve calcification on the elasticity of the ascending aortic and its correlation were analyzed.Results The％A,AD,and AC of the calcification group were lower than those of the non calcification group,but the ASI was higher than that of the non calcification group,the difference was statistically significant(P＜0.05).The number of calcified leaflets affected ascending aortic elasticity,with comparisons between groups A and B,the difference was no statistically significant(P＞0.05),groups A and C,and groups B and C,the difference was statistically significant(P＜0.05).Calcification score was negatively correlated with％A,AD,and AC,and positively correlated with ASI.Conclusion Aortic valve calcification can affect the elasticity of the ascending aortic,and more than two calcified leaflets have more significant effects on the elasticity of the ascending aortic.

Objective Cervical disc herniation(CDH)is one of the common orthopaedic diseases.With the in-depth study of it and the development of cervical implants,the establishment of cervical fusion animal models has become an indispensable part.Notably however,studies of the establishment and evaluation of cervical fusion animal models in China are currently lacking.This study aimed to provide a suitable animal model and evaluation scheme for implants for cervical spine-related research.Methods Small-tailed Han sheep were chosen for anterior cervical discectomy fusion(ACDF)after modified surgery,and a polyetheretherketone(PEEK)interbody fusion cage(Cage)(control group),3D-printed Ti6Al4V Cage(group 1),and new method Ti6Al4V Cage(group 2)were implanted in different cervical segments(C2/3～C4/5)in each sheep,respectively.Hematology and histopathological analyses were carried out after surgery to evaluate recovery of sheep and the biosafety of the materials.Bone in-growth and bone fusion were assessed by X-ray,computed tomography(CT),Micro-CT and quantitative analysis,hard tissue section staining,and biomechanical tests.Results The modified ACDF ovine model was established successfully.There were no significant differences in important hematology indexes(P＞0.05)and histopathological analysis showed no pathological changes,such as inflammatory cell infiltration.The implants had good biosafety.Furthermore,X-ray and CT examinations showed that the position of internal fixation and the interbody fusion were good.Micro-CT and quantitative analysis at 3 and 6 months after operation showed that compared with PEEK Cage group,the bone volume/total volume and trabecular number were significantly increased(P＜0.01)while the trabecular spacing was significantly decreased in the new method Ti6Al4V and 3D-printed Ti6Al4V groups compared with the PEEK Cage group(P＜0.01).Moreover,the new method new method Ti6Al4V Cage group had more bone growth(P＜0.01).Hard tissue section staining demonstrated that the pores of the new method Ti6Al4V Cage and 3D-printed Ti6Al4V Cage had obvious bone growth and relatively dense pores in the new method Ti6Al4V and 3D-printed Ti6Al4V groups,and the combination was slightly better than that of PEEK Cage.Biomechanical evaluation indicated that the new method Ti6Al4V Cage and 3D-printed Ti6Al4V Cage reduced the range of cervical flexion-extension,lateral bending,and axial rotation(P＜0.05)compared with the PEEK cage,as well as enhancing the stability of the cervical vertebra,and the new method Ti6Al4 V Cage was more advantageous(P＜0.05).Conclusions After the establishment of the modified ACDF ovine model,reasonable and effective assessment method were used to demonstrate the suitability and effectiveness of the model and the good biosecurity of all three Cage materials.Compared with the PEEK Cage,the new method Ti6Al4V Cage and 3D-printed Ti6Al4V Cages showed better performances in terms of bone growth and bone fusion,which could enhance the stability of the cervical vertebrae.The new method Ti6Al4V Cage was particularly advantageous.

Objective:To analyze the effect of long-term care insurance on the incidence of falls in old people with disability, and the modification effect of different living arrangements.Methods:Based on the discharge diagnosis records of the hospitalization in urban residents who applied for long-term care insurance in Chengdu from July 2014 to June 2021, those who received long-term care insurance were selected as the intervention group and those who received no long-term care insurance were selected as the control group, the changes in the incidence of falls before and after the long-term care were analyzed using difference-in-differences method, and the modification effects of different living arrangements were explored using stratified analysis.Results:Long-term care insurance significantly reduced the risk for monthly incidence of falls in older adults [average treatment effects on treated (ATT) = -1.21% (95% CI: -1.82%--0.60%)], and the effect increased over time (ATT=-1.26%, 95% CI: -1.93%--0.59%). Long-term care insurance had a significant effect on reducing the incidence of falls in old people living with spouses/family members (ATT=-0.92%, 95% CI: -1.47%--0.37%) and in nursing facilities/hospitals (ATT=-2.10%, 95% CI: -3.81%--0.40%), but it had no significant effect in those living alone. Conclusions:Long-term care insurance can effectively reduce the incidence of falls in old people with disability, showing a positive effect. Living with family members or in nursing facilities/hospitals has a modification effect of the implementation of long-term care insurance policy. It is necessary to pay attention to key populations in the future and expand the coverage of long-term care insurance.