This paper explains the mechanism of the mutual switching between physiological sleep and wakefulness from the aspects of the sleep circadian system and the sleep homeostasis system. In the circadian rhythm system, with the suprachiasmatic nucleus as the core, the anatomical connections between the suprachiasmatic nucleusand various systems that affect sleep are summarized, starting from the suprachiasmatic nucleus, passing through the four pathways of the melatonin system, namely, subventricular area of the hypothalamus, the ventrolateral nucleus of the preoptic area, orexin neurons, and melatonin, then the related mechanisms of their regulation of sleep and wakefulness are expounded. In the sleep homeostasis system, with adenosine and prostaglandin D2 as targets, the role of hypnogen in sleep arousal mechanisms in regulation is also expounded.

A derivatizaton method combined with gas chromatography-mass spectrometry(GC-MS)was established for detection of isobutyl chloroformate(IBCF)residue in active pharmaceutical ingredient of agatroban.The extraction and derivatization reagents,derivatization time,qualitative and quantitative ions were selected and optimized,respectively.The possible mechanism of derivatization and characteristic fragment ions fragmentation were speculated.The agatroban samples were dissolved and extracted by methanol,and the residual IBCF was derived with methanol to generate methyl isobutyl carbonate(MIBCB).After 24 h static derivatization at room temperature,IBCF was completely transformed into MIBCB,which could be used to indirectly detect IBCF accurately.The results showed that the linearity of this method was good in the range of 25-500 ng/mL(R2=0.9999).The limit of detection(LOD,S/N=3)was 0.75 μg/g,and the limit of quantification(LOQ,S/N=10)was 2.50 μg/g.Good recoveries(95.2%-97.8%)and relative standard deviations(RSDs)less than 3.1%(n=6)were obtained from agatroban samples at three spiked levels of IBCF(2.50,25.00,50.00 μg/g),which showed good accuracy of this method.Good precision of detection results was obtained by different laboratory technicians at different times,the mean value of spiked sample solution(25.00 μg/g)was 24.28 μg/g,and the RSD was 2.1%(n=12).The durability was good,minor changes of detection conditions had little effect on the results.Under the original condition and conditions with initial column temperature±5℃,heating rate±2℃/min,column flow rate±0.1 mL/min,the IBCF content of spiked sample solution(25.00 μg/g)was detected,the mean value of detection results was 24.16 μg/g,and the RSD was 2.2%(n=7).Eight batches of agatroban samples from two manufacturers were detected using the established method,and the results showed that no IBCF residue was detected in any of these samples.The agatroban samples could be dissolved by methanol,and then the IBCF residue could be simultaneously extracted and derived with methanol as well.This detection method had the advantages of simple operation,high sensitivity,low matrix effect and accurate quantification,which provided a new effective method for detection of IBCF residue in agatroban.

AIM:To establish a model of meibomian gland dysfunction in rats induced by eyeliner tattoo and investigate its potential mechanisms.METHODS:A total of 40 SD rats were selected, with 30 randomly chosen to have eyeliner tattoo applied their right eyes and designated as the eyeliner group. The remaining 10 rats were not given any treatment and served as the normal group. The corneal morphology of both groups was observed using a slit lamp at 1, 2, and 4 wk after establishment, and the tear film break-up time(BUT), Schirmer I test(SIt), corneal fluorescein staining score, and corneal irregularity score were calculated. The corneal Placido rings were examined using an ocular surface analyzer, and the corneal tissue structures of both groups were observed under a confocal microscope. After 4 wk and completion of clinical indicator recording, the eyeballs and upper and lower eyelid tissues were taken for pathological examination. The meibomian gland structures were observed through HE staining, the conjunctival goblet cells were observed using PAS staining, and the lipid droplets were observed with ORO staining.RESULTS:The slit lamp examination results showed that the eyeliner group rats exhibited in situ black pigmentation in the eyelids, with no eyelid deformation or scarring. The corneal epithelium was rough, with positive fluorescein staining, presenting as spotty staining that worsened over time. Compared with the normal group, the BUT was significantly shortened, tear secretion volume was significantly decreased, and the corneal fluorescein staining score and corneal irregularity score were significantly increased at 1, 2, and 4 wk after modeling in the eyeliner group(all P<0.01). The corneal confocal microscopy results showed a decrease in corneal epithelial cells in the eyeliner group, with the appearance of abnormally bright cells, and inflammatory cell infiltration visible in the stromal layer. The ORO staining results revealed a decrease in lipid droplets in the eyeliner group, showing a downward trend with increasing observation time. The HE staining results showed that pigment blocked the meibomian gland openings in the eyeliner group, and the density of meibomian gland acini showed a downward trend over time. The PAS staining results showed a decreasing trend in the number of PAS-positive cells in the eyeliner group.CONCLUSION:Eyeliner tattoo can induce meibomian gland dysfunction, and the blockage of meibomian gland openings caused by the pigment particles used may be an important cause of meibomian gland dysfunction.

Objective To study the effects of Chrysanthemum Flos on blood pressure of spontaneously hypertensive rats(SHR)and evaluate its antioxidant activity in vitro and in vivo.Methods SHR were randomly divided into model,control and experimental-L,-H groups with 10 rats per group,and 10 WKY rats as blank group.Experimental-H,-L groups were given 2.10 and 0.525 g·kg-1 Chrysanthemum Flos extract by gavage;control group received 5.25 mg·kg-1 losartan by gavage;blank and model groups were given the same volume of 0.9％NaCl solution by gavage.Rats in each group were gavaged once a day for 8 weeks.After 8 weeks of continuous intragastric administration,the systolic blood pressure(SBP)and diastolic blood pressure(DBP)were observed.The contents of catalase(CAT),superoxide dismutase(SOD),glutathione peroxidase(GSH)and malondialdehyde(MDA)in serum were measured with kit colorimetry method.The in vitro free radical scavenging rates of Chrysanthemum Flos extract were detected by 1,1-diphenyl-2-picrylhydrazyl(DPPH)and 2,2'-amino-di(2-ethyl-benzothiazoline sulphonic acid-6)ammonium salt(ABTS)methods.Results The SBP of blank,model,control and experimental-H,-L groups were(132.00±2.45),(204.00±4.55),(171.00±2.16),(181.00±3.74)and(184.67±4.78)mmHg;the DBP were(73.33±4.03),(175.67±3.40),(120.33±0.94),(125.33±2.87)and(125.67±2.36)mmHg;the contents of serum CAT were(9.24±3.99),(8.40±2.98),(9.24±2.42),(8.59±2.70)and(8.49±1.47)U·mL-1;the contents of serum SOD were(122.40±12.30),(75.30±28.37),(125.39±31.35),(110.92±26.14)and(103.37±22.31)U·mL-1;the contents of serum GSH were(117.93±10.18),(78.29±23.68),(118.57±26.08),(109.89±20.52)and(98.73±14.71)U·mL-1;the contents of serum MDA were(8.36±2.08),(8.45±3.38),(8.22±3.04),(7.09±3.21)and(7.24±3.32)nmol·L 1,respectively.Compared with model group,the differences of above indicators in control group and experimental-H,-L groups were statistically significant(P＜0.05,P＜0.01).Chrysanthemum Flos extract showed certain free radical scavenging ability in vitro.The highest scavenging rates of DPPH and ABTS were 90.29％and 92.67％,respectively.Conclusion Chrysanthemum Flos extract had good antihypertensive activity.The antioxidation ability might be its antihypertensive mechanisms.

Objective To analyze the influence of midazolam and propofol on sedation effect and blood gas indicators in elderly patients undergoing mechanical ventilation after cardiopulmonary bypass(CPB)cardiac surgery.Methods The elderly patients with mechanical ventilation after CPB cardiac surgery were grouped according to cohort method,including midazolam group(group M),propofol group(group P)and midazolam-propofol combined administration group(group M-P).Group M was treated with midazolam(intravenous injection of 0.05-0.10 mg kg-1 midazolam for sedation induction,and then continuously intravenous injection of 0.05-0.15 mg·kg-1·h-1 midazolam by micropump),and group P was treated with propofol(intravenous injection of 0.5 mg·kg-1 propofol for sedation induction,and then continuously intravenous injection of 0.5-2.0 mg·kg-1·h-1 propofol by micropump),and group M-P was given combined administration of midazolam and propofol(intravenous injection of 0.02-0.05 mg·kg-1 midazolam and 0.2-0.5 mg·kg-1 propofol for sedation induction and then continuously intravenous pump of 0.05-0.1 mg·kg-1 midazolam and 0.5-0.8 mg·kg·h-1 propofol).The sedation effect,blood gas indicators,hemodynamic indicators,extubation time,intensive care unit(ICU)stay time and treatment cost were compared among the three groups,and the adverse drug reactions during sedation therapy were recorded.Results There were 43 cases in group M,44 cases in group P,39 cases in group M-P.The drug onset times in groups M,P and M-P were(77.94±12.05),(18.18±5.20)and(21.25±9.36)s;the times to achieve satisfactory sedation effect were(42.57±11.41),(22.63±8.17)and(23.98±10.25)min;the recovery times after withdrawal were(59.30±14.86),(19.83±5.44)and(22.16±6.29)min;the extubation times were(1.61±0.20),(1.45±0.22)and(1.37±0.15)d;the ICU stay times were(2.17±0.29),(1.91±0.36)and(1.84±0.25)d;the treatment costs were(186.59±60.83),(922.97±164.34)and(375.03±71.16)thousand yuan;and the total incidence rates of adverse drug reactions were 34.88％,4.55％and 7.69％respectively,all with significant difference(all P＜0.05).There were no statistically significant differences in mean arterial pressure(MAP),heart rate(HR),oxygen saturation(SpO2),partial pressure of oxygen(PaO2),partial pressure of carbon dioxide(PaCO2)at T0,T1,T2,T3 and T4 among the three groups(all P＞0.05).Conclusion Combined administration of midazolam and propofol in elderly patients underwent mechanical ventilation after CPB cardiac surgery has a significant sedation effect,and it is conducive to reducing the dosages of sedative drugs,and it has small impact on blood gas indicators and hemodynamic indicators of patients.Compared with midazolam alone,it is more beneficial to shortening the extubation time and ICU stay and reducing the total incidence rate of adverse drug reactions,and compared with propofol alone,it is more beneficial to reducing treatment cost,and is a more ideal sedation administration model.

Stable gait is the foundation for elderly people to maintain basic daily physical activities, and whole-body vibration training can help improve gait problems in the elderly.Whole body vibration training improves gait in the elderly through various mechanisms, including improving muscle strength decline and sarcopenia, improving osteoporosis, enhancing balance ability, enhancing posture control, and alleviating gait sequelae in chronic disease patients.This article explores the application effect of whole-body vibration training in improving gait in the elderly, providing ideas for clinical workers to use new exercise methods to promote physical health in the elderly.

Objective:To investigate the surgical situations and perioperative outcome of pancreaticoduodenectomy in Jiangsu Province and the influencing factors for postoperative 90-day mortality.Methods:The retrospective case-control study was conducted. The clinicopathological data of 2 886 patients who underwent pancreaticoduodenectomy in 21 large tertiary hospitals of Jiangsu Quality Control Center for Pancreatic Diseases, including The First Affiliated Hospital of Nanjing Medical University, from March 2021 to December 2022 were collected. There were 1 732 males and 1 154 females, aged 65(57,71)years. Under the framework of the Jiangsu Provincial Pancreatic Disease Quality Control Project, the Jiangsu Quality Control Center for Pancreatic Diseases adopted a multi-center registration research method to establish a provincial electronic database for pancrea-ticoduodenectomy. Observation indicators: (1) clinical characteristics; (2) intraoperative and post-operative conditions; (3) influencing factors for 90-day mortality after pancreaticoduodenectomy. Measurement data with skewed distribution were represented as M( Q1, Q3) or M(IQR), and comparison between groups was conducted using the Mann-Whitney U test. Count data were expressed as absolute numbers or constituent ratio, and comparison between groups was conducted using the chi-square test, continuity correction chi-square test and Fisher exact probability. Maximal Youden index method was used to determine the cutoff value of continuous variables. Univariate analysis was performed using the corresponding statistical methods based on data types. Multivariate analysis was performed using the Logistic multiple regression model. Results:(1) Clinical characteristics. Of the 2 886 patients who underwent pancreaticoduodenectomy, there were 1 175 and 1 711 cases in 2021 and 2022, respectively. Of the 21 hospitals, 8 hospitals had an average annual surgical volume of <36 cases for pancreaticoduodenectomy, 10 hospitals had an average annual surgical volume of 36-119 cases, and 3 hospitals had an average annual surgical volume of ≥120 cases. There were 2 584 cases performed pancreaticoduodenectomy in thirteen hospitals with an average annual surgical volume of ≥36 cases, accounting for 89.536%(2 584/2 886)of the total cases. There were 1 357 cases performed pancrea-ticoduodenectomy in three hospitals with an average annual surgical volume of ≥120 cases, accounting for 47.020%(1 357/2 886) of the total cases. (2) Intraoperative and postoperative conditions. Of the 2 886 patients, the surgical approach was open surgery in 2 397 cases, minimally invasive surgery in 488 cases, and it is unknown in 1 case. The pylorus was preserved in 871 cases, not preserved in 1 952 cases, and it is unknown in 63 cases. Combined organ resection was performed in 305 cases (including vascular resection in 209 cases), not combined organ resection in 2 579 cases, and it is unknown in 2 cases. The operation time of 2 885 patients was 290(115)minutes, the volume of intra-operative blood loss of 2 882 patients was 240(250)mL, and the intraoperative blood transfusion rate of 2 880 patients was 27.153%(782/2 880). Of the 2 886 patients, the invasive treatment rate was 11.342%(327/2 883), the unplanned Intensive Care Unit (ICU) treatment rate was 3.087%(89/2 883), the reoperation rate was 1.590%(45/2 830), the duration of postoperative hospital stay was 17(11)days, the hospitalization mortality rate was 0.798%(23/2 882), and the failure rate of rescue data in 2 083 cases with severe complications was 6.529%(19/291). There were 2 477 patients receiving postoperative 90-day follow-up, with the 90-day mortality of 2.705%(67/2477). The total incidence rate of complication in 2 886 patients was 58.997%(1 423/2 412). The incidence rate of severe complication was 13.970%(291/2 083). The comprehensive complication index was 8.7(22.6) in 2 078 patients. (3) Influencing factors for 90-day mortality after pancreaticoduodenectomy. Results of multivariate analysis showed that age ≥ 70 years, postoperative invasive treatment, and unplanned ICU treatment were independent risk factors for 90-day mortality after pancreaticoduodenectomy ( odds ratio=2.403, 2.609, 16.141, 95% confidence interval as 1.281-4.510, 1.298-5.244, 7.119-36.596, P<0.05). Average annual surgical volume ≥36 cases in the hospital was an independent protective factor for 90-day mortality after pancreaticoduodenectomy ( odds ratio=0.368, 95% confidence interval as 0.168-0.808, P<0.05). Conclusions:Pancreaticoduodenectomy in Jiangsu Province is highly con-centrated in some hospitals, with a high incidence of postoperative complications, and the risk of postoperative 90-day mortality is significant higher than that of hospitallization mortality. Age ≥ 70 years, postoperative invasive treatment, and unplanned ICU treatment are independent risk factors for 90-day motality after pancreaticoduodenectomy, and average annual surgical volume ≥36 cases in the hospital is an independent protective factor.

Objective To propose a Q factor-based fatigue vibration evaluation method of the ultrasonic knife tip.Methods Firstly,an ultrasonic cutter fatigue testing table was established to realize repeated cutting,which was composed of a power supply module,a three-axis moving module,an ultrasonic cutter clamping module and a control module.Secondly,10 ultrasonic knives of some brand underwent fatigue testing with the table,during which non-contact measurement of the ultrasonic knife tip vibration was carried out and the Q factors were calculated at the five periods of the fatigue test,including the periods before cutting,after 500 times of cutting,after 1 000 times of cutting,after 2 000 times of cutting and after 3 000 times of cutting.Finally,the average cutting speed and burst pressure for coagulated vessels were computed at each period to validata the effectiveness of the method proposed.Results It's indicated that Q factor could effectively reflect the fatigue degradation of the ultrasonic knife tip,while the average cutting speed and burst pressure for coagulated vessels were difficult to efficiently evaluate the fatigue degradation level of the ultrasonic knife tip due to the uncertainty factors in the measurement process.Conclusion The proposed Q factor-based evaluation method can directly evaluate fatigue vibration of the ultrasonic knife tip in an accurate and quantitative manner.[Chinese Medical Equipment Journal,2024,45(6):17-22]

Objective To carry out accurate quantative evaluation of MRI scanning noise based on laser vibrometry technology.Methods Skull and spine MRI was performed with mute and conventional sequences.A laser vibrometry device was used to sample the surface vibration noise at the outer edge of the inspection hole of MRI system according to GB/T 16539-1996 Acoustics—Determination of sound power levels of noise sources using vibration velocity—Measurement for seal machinery,and the indicators of sound power level,sound pressure level and perceived noise level obtained by the three calculation methods(LPN1,LPN2 and LPN3)were analyzed with some dedicated MRI noise analysis software.Results The peak sound pressure levels for conventional and mute sequences of skull scanning were 81 and 63 dB(A),respectively,and mute sequence reduced the noise level significantly;the peak sound pressure levels for conventional and mute sequences of spine scanning were 79 and 75 dB(A),respectively,and the noise reduction level was significantly lower than that of skull scanning.Significant differences in noise reduction were not found in spine scanning sequences,while were found in skull scanning sequences.During spine and skull scanning LPN1,LPN2 and LPN3 obtained by the three calculation methods of conventional and mute sequences were all higher than the overall sound power and overall pressure levels obviously.Conclusion Mute sequence can not realize linear noise reduction for the whole frequency band,the perceived noise of the human ear during MRI scanning is related directly to the scanning sequence,and there may be some bias when only one physical indicator is involved in the noise evaluation of MRI system.[Chinese Medical Equipment Journal,2024,45(10):20-24]

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in tertiary hospitals in major regions of China in 2022.Methods Clinical isolates from 58 hospitals in China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2022 Clinical &Laboratory Standards Institute(CLSI)breakpoints.Results A total of 318 013 clinical isolates were collected from January 1,2022 to December 31,2022,of which 29.5％were gram-positive and 70.5％were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species(excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi)was 28.3％,76.7％and 77.9％,respectively.Overall,94.0％of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 90.8％of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis showed significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 94.2％in the isolates from children and 95.7％in the isolates from adults.The resistance rate to carbapenems was lower than 13.1％in most Enterobacterales species except for Klebsiella,21.7％-23.1％of which were resistant to carbapenems.Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.1％to 13.3％.The prevalence of meropenem-resistant strains decreased from 23.5％in 2019 to 18.0％in 2022 in Pseudomonas aeruginosa,and decreased from 79.0％in 2019 to 72.5％in 2022 in Acinetobacter baumannii.Conclusions The resistance of clinical isolates to the commonly used antimicrobial agents is still increasing in tertiary hospitals.However,the prevalence of important carbapenem-resistant organisms such as carbapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a downward trend in recent years.This finding suggests that the strategy of combining antimicrobial resistance surveillance with multidisciplinary concerted action works well in curbing the spread of resistant bacteria.