[Application value of arousal threshold in obstructive sleep apnea]

The pathogenesis of obstructive sleep apnea (OSA) includes anatomical and non-anatomical factors, and the arousal threshold (ArTH) is one of the important non-anatomical factors. At present, the main method is to assess the increased respiratory effort due to arousal to determine the arousal threshold, and invasive epiglottic or esophageal manometry is the gold standard, while the non-invasive continuous positive airway pressure (CPAP) method and polysomnography (PSG) ventilation signal conversion method are also widely used. Arousal threshold is expected to serve as an important evaluation index and potential target for drug therapy in OSA, which is of great importance for realization of precise treatment of OSA. This article focused on the method and clinical significance of OSA arousal threshold.

[Clinical effects of expanded frontal flap and flip scar flap in repairing partial nasal defect]

Objective: To investigate the clinical effects of expanded frontal flap and flip scar flap in repairing partial nasal defect. Methods: A retrospective observational study was conducted. From January 2012 to January 2022, 26 patients with partial nasal defects who met the inclusion criteria were admitted to the First Affiliated Hospital of Air Force Medical University, including 19 males and 7 females, aged 5 to 61 years. The surgery was performed in 4 stages. In the first stage, a rectangular skin and soft tissue expander (hereinafter referred to as expander) with suitable rated capacity was planted in frontal region and expanded by injecting water regularly. In the second stage, flip scar flap was grafted to reconstruct nasal inner lining, whose area was about 10% larger than the area of defect. The expanded frontal flap with pedicle was transferred to repair the nasal defect, whose pedicle was supraorbital vessel or supratrochlear vessel on the contralateral side of the defect, and the area of expanded flap was 20% larger than the nasal defect area after resection and flipping of scar flap. The donor site of expanded flap was sutured directly. After 3 weeks of flap transferring, the flap was delayed in the third stage. After 1 week of delaying operation, the pedicle of flap was cut off in the fourth stage. The number, rated capacity, injection volume, and expansion time of embedded expanders were recorded. The occurrences of complications including infection, hematoma, ulceration of expanded flap after the first stage operation, and blood supply disorder or necrosis of flap after operation in the second and fourth stages were observed. All the patients were followed up for 1 year at least, and the color of flap, scar of frontal donor site, symmetry of bilateral eyebrows, and the nasal appearance and ventilated function of external nasal tract were observed. Results: A total of 26 expanders were embedded in 26 patients. The rated capacity of expanders ranged from 100 to 300 mL. The injection volume was 1.0 to 1.5 times of the rated capacity of expanders. The expansion time ranged from 2.5 to 4.0 months, with an average time of 3 months. There were no complications occurred after each operation. The follow-up showed that the color of flap was similar to the normal nasal skin, the scar of frontal region was not obvious, the bilateral eyebrows were basically symmetrical, the nose had excellent appearance, ventilation function of external nasal tract was not affected, while some of the patients had downward rotation or unapparent tip-defining point of nose. Conclusions: Using the flip scar flap to reconstruct the nasal inner lining and pre-expanded frontal flap to reconstruct the nasal skin, without free cartilage transplantation to repair the partial nasal defects can achieve satisfied nasal appearance post operation, without abnormal external nasal ventilation function.

Mapping Chinese annual gross primary productivity with eddy covariance measurements and machine learning

Annual gross primary productivity (AGPP) is the basis for grain production and terrestrial carbon sequestration. Mapping regional AGPP from site measurements provides methodological support for analysing AGPP spatiotemporal variations thereby ensures regional food security and mitigates climate change. Based on 641 site-year eddy covariance measuring AGPP from China, we built an AGPP mapping scheme based on its formation and selected the optimal mapping way, which was conducted through analysing the predicting performances of divergent mapping tools, variable combinations, and mapping approaches in predicting observed AGPP variations. The reasonability of the selected optimal scheme was confirmed by assessing the consistency between its generating AGPP and previous products in spatiotemporal variations and total amount. Random forest regression tree explained 85 % of observed AGPP variations, outperforming other machine learning algorithms and classical statistical methods. Variable combinations containing climate, soil, and biological factors showed superior performance to other variable combinations. Mapping AGPP through predicting AGPP per leaf area (PAGPP) explained 86 % of AGPP variations, which was superior to other approaches. The optimal scheme was thus using a random forest regression tree, combining climate, soil, and biological variables, and predicting PAGPP. The optimal scheme generating AGPP of Chinese terrestrial ecosystems decreased from southeast to northwest, which was highly consistent with previous products. The interannual trend and interannual variation of our generating AGPP showed a decreasing trend from east to west and from southeast to northwest, respectively, which was consistent with data-oriented products. The mean total amount of generated AGPP was 7.03 ± 0.45 PgC yr^-1 falling into the range of previous works. Considering the consistency between the generated AGPP and previous products, our optimal mapping way was suitable for mapping AGPP from site measurements. Our results provided a methodological support for mapping regional AGPP and other fluxes.

[Establishment and validation of a clinical prediction model for infection risk at the placement sites of skin and soft tissue expanders]

Objective: To establish a clinical prediction model for infection risk at the placement sites of skin and soft tissue expanders (hereinafter termed as expanders) and to validate the predictive value of the model. Methods: A retrospective observational study was conducted. Totally 2 934 patients who underwent skin and soft tissue dilatation surgery in the Department of Plastic Surgery of the First Affiliated Hospital of Air Force Medical University from January 2009 to December 2018 and met the selection criteria were included. There were 1 867 males and 1 067 females, with a median age of 18 years. Totally 3 053 skin and soft tissue expansion procedures were performed with 4 266 expanders implanted. The following indexes were selected as predictor variables, including patients' age, gender, marital status, ethnicity, hospital admission, surgical indication, disease duration, with/without history of smoking, history of drinking, history of blood transfusion, history of underlying diseases, and inability to use cephalosporin antibiotics due to allergy, number of expander in a single placement, rated volume of expander, water injection rate of expander in the first time, placement site of expander, anesthesia method, duration of operation, and with/without postoperative hematoma evacuation, and infection at the placement site of expander as the outcome variable. Univariate analysis of the data was performed using least absolute shrinkage and selection operator (LASSO) regression to screen the potential risk factors affecting infection at the placement sites of expanders, the factors selected by the univariate analysis were subjected to binary multivariate logistic regression analysis to screen the independent risk factors affecting infection at the placement sites of expanders, and a nomogram prediction model for the occurrence of infection at the placement sites of expanders was established. The C index and Hosmer-Lemeshow goodness of fit test were used to evaluate the discrimination and accuracy of the model, respectively, and the bootstrap resampling was used for internal verification. Results: The results of LASSO regression showed that age, gender, hospital admission, surgical indication, disease duration, history of drinking, history of heart disease, history of viral hepatitis, history of hypertension, inability to use cephalosporin antibiotics due to allergy, number of expander in a single placement, rated volume of expander, placement site of expander, postoperative hematoma evacuation were the potential risk factors for infection at the placement sites of expanders (regression coefficient=-0.005, 0.170, 0.999, 0.054, 0.510, -0.003, 0.395, -0.218, 0.029, 0.848, -0.116, 0.175, 0.085, 0.202). Binary multivariate logistic regression analysis showed that male, emergency admission, disease duration ≤1 year, inability to use cephalosporin antibiotics due to allergy, rated volumes of expanders ≥200 mL and <400 mL or ≥400 mL, and expanders placed in the trunk or the limbs were the independent risks factors for infection at the placement sites of expanders (odds ratio=1.37, 3.21, 2.00, 2.47, 1.70, 1.73, 1.67, 2.16, 95% confidence interval=1.04-1.82, 1.09-8.34, 1.38-2.86, 1.29-4.41, 1.07-2.73, 1.02-2.94, 1.09-2.58, 1.07-4.10, P<0.05 or P<0.01). The C index for evaluating the discriminative degree of the model was 0.63, the Hosmer-Lemeshow goodness of fit test for evaluating the accuracy of the model showed P=0.685, and the C index for internal validation by the bootstrap resampling was 0.60. Conclusions: Male, emergency admission, disease duration ≤1 year, inability to use cephalosporin antibiotics due to allergy, rated volume of expander ≥200 mL, and expanders placed in the trunk or the limbs are the independent risk factors for infection at the placement sites of expanders. The clinical prediction model for infection risk at the placement sites of expanders was successfully established based on these factors and showed a certain predictive effect.

[The study of locating facial nerve precisely in middle ear surgery based on clinical anatomy]

Objective:To investigate the methods of locating facial nerve precisely in middle ear surgery through the observation and measurement of the facial nerve and surrounding anatomical structures and to provide reference for the middle ear surgery.Method:Combined surgical approach on 15 cases (30 sides) fresh adult cadaveric specimens were dissected, observed the characteristics of facial nerve and its shape and spatial relationship of the surrounding structures, and measured the distance between the facial nerve and its surrounding structures.Result:The shortest distance from the midpoint of the posterior wall of external auditory canal (annulus level) to the vertical segment of the facial nerve was (3.37±0.34)mm, the shortest distance from the leading edge of the sigmoid sinus to the vertical segment of facial nerve was (7.40±0.71)mm, the shortest distance from the lateral margin of jugular bulb to the facial nerve was (5.58±0.79)mm, the shortest distance from Henle crest to the pyramidal segment of facial nerve was (12.76±1.24)mm, the shortest distance between the pyramidal segment of facial nerve and the posterior short limb of incus was (1.56±0.35)mm, the shortest distance between the pyramidal segment of facial nerve and the lower edge of posterior semicircular canal was (2.56±0.41) mm, the shortest distance between the lower edge of horizontal semicircular canal and the horizontal segment of facial nerve was (1.28±0.32) mm, the shortest distance between the upper edge of vestibular window and the horizontal segment of facial nerve was (0.67±0.15)mm.Conclusion:A good command of the anatomy of temporal bone as well as the methods of locating facial nerve will provide the key to reduce the probability of iatrogenic facial nerve injury in middle ear surgery.

Sealing the intramedullary femoral canal with autologous bone plug in total knee arthroplasty

In a prospective study of 262 consecutive patients with total knee arthroplasty, we compared the postoperative suction drainage and transfusion requirement in cases in which the defect made by the femoral intramedullary rod was either unplugged (n = 134) or plugged (n = 128). All operations were performed with a single surgical approach and technique. Inflammatory arthritis and lateral releases were excluded. Blood loss was recorded at 24, 48, and 72 hours. The difference in postoperative suction drainage was not statistically significant. The hemoglobin decrease in the unplugged group (3.5 g/dL) was different from that in the plugged group (2.3 g/dL) (P<.05). Of patients, 64.4% (n = 85) in the unplugged group and 35.9% (n = 46) in the plugged group required transfusion (P<.05). Sealing the femoral canal is effective in reducing hemoglobin decrease and blood transfusion in total knee arthroplasty.

Determination of chemical composition of commercial honey by near-infrared spectroscopy

The feasibility of using near-infrared spectroscopy to determine chemical composition of commercial honey was examined. The influences of various sample presentation methods and regression models on the performance of calibration equations were also studied. Transmittance spectra with 1 mm optical path length produced the best calibration for all constituents examined. The regression model of modified partial least squares (mPLS) was selected for the calibration of all honey constituents except moisture, for which the optimal calibration was developed with PLS. Validation of the established calibration equations with independent samples showed that the spectroscopic technique could accurately determine the contents of moisture, fructose, glucose, sucrose, and maltose with squared correlation coefficients (R(2)) of 1.0, 0.97, 0.91, 0.86, and 0.93 between the predicted values and the reference values. The prediction accuracy for free acid, lactone, and hydroxymethylfurfural (HMF) contents in honey was poor and unreliable. The study indicates that near-infrared spectroscopy can be used for rapid determination of major components in commercial honey.

Changes in refractive trends and optical components of Hong Kong Chinese aged over 40 years

The age trends of refractive errors, astigmatism and optical components were studied in 220 Chinese subjects aged over 40 years. Myopia did not dominate in this age group. With increasing age, the prevalence of hyperopia increases from 2% at age 40-45 years to 66% at age > 65 years. Against-the-rule astigmatism was more prevalent than the other types. Significant correlations were found between age and spherical equivalent power, age and vitreous depth and axial length. Sex differences were found among the optical components but not in the refractive error. Myopia appears to be more prevalent among the younger age groups than the older age groups of the Hong Kong Chinese population, and the importance of genetics in determination of refractive error is called into question by these findings.

[A field study on the post-inoculation reaction and immunological effects in vaccinated population immunized with "Zhejiang type-D" leptospiral vaccine]

A comparative study on the post-inoculation and antibody responses after inoculation with two different dosage (1ml, 2ml) of "zhejiang type-D" leptospiral vaccine was carried out. There was no general reaction in all of the vaccinated people after immunization. The GMT values of antibody against leptospire were 3.08-7.91 times in 1ml dose group and 3.48-9.57 times in 2ml dose group more than pre-vaccination respectively. 3 months after immunization the levels of specific antibody still were high in most vaccinated people, whatever in 1ml dose or 2ml dose of immunization. However the antibody couldn't be detected in part of vaccinated people at that time, but there was no difference between the two different dosages. During the epidemic season, there was no leptospirosis case (0/3260) in the 1ml group, 1 case (1/625) in the 2 ml group while there was 9/3970 in the control group.

Olfactory bulbectomy prevents the gonadal regression associated with short photoperiod in male golden hamsters

In male rats, pre-pubertal olfactory bulbectomy (BX) unmasks photoperiodic responsiveness so that maintenance of BX animals on short photoperiod results in a pineal gland mediated gonadal regression (Nelson and Zucker, Neuroendocrinology, 32 (1981) 266). The objective of the present study was to determine the effect of BX in Syrian hamsters, a species where short photoperiod alone induces a pineal gland induced testicular regression. Pre-pubertal (25-days old) Syrian hamsters underwent either sham BX, BX, or pinealectomy (PX) plus BX. One half of each group was then placed on an LD 14:10 photoperiod and the other half on LD 6:18. Thirteen weeks later all animals were decapitated. In the animals on LD 14:10, BX resulted in a slight but highly significant increase in testes weight but had no effect on other parameters examined. Sham BX hamsters on LD 6:18 had regressed testes and reduced serum testosterone levels, but these effects of short photoperiod were reversed in BX hamsters, so that the testes and seminal vesicles remained large. In addition, serum LH and testosterone levels were elevated following BX of the animals on LD 6:18. These results indicate that the olfactory bulbs tonically inhibit the reproductive system even in male hamsters maintained on long photoperiod and that olfactory bulbectomy prevents gonadal regression in male Syrian hamsters on short photoperiod, an effect which is the opposite of results obtained in rats on short photoperiod. Elucidation of the neural pathways involved and the nature of the relationship between the olfactory bulb and the pineal gland or photoperiodism remains for further investigation.