[Research status and reflection on animal models of sepsis].

Infectious diseases are the leading cause of death in children. Sepsis is a critical infectious disease that causes death in children globally, with a high morbidity and mortality rate. It poses a serious threat to children's health. Early diagnosis has become the key to treating severe sepsis. The establishment of animal models of sepsis can help people better diagnose sepsis and take interventions to improve the prognosis of sepsis patients. This study reviews the types, advantages and disadvantages of existing animal models of sepsis and proposes the optimization of these models to provide a reference basis for the selection and optimization of experimental models and the promotion of the "reverse transformation" of sepsis into clinical practice.

[The diagnostic value of inflammation-related genes in bronchopulmonary dysplasia].

This study aims to explore the diagnostic value of inflammation-related genes in peripheral blood mononuclear cells in bronchopulmonary dysplasia (BPD). By using bioinformatics analysis, three datasets including GSE32472, GSE125873, and GSE220135, which contain whole-genome expression profile data of 251 neonates, were included. The GSE32472 dataset was used as a training dataset to detect differentially expressed genes between non-BPD and BPD neonates in peripheral blood mononuclear cells. The gene enrichment analysis (GSEA) was used to detect the pathway enrichment of up-regulated genes in BPD newborns. The main regulatory factors analysis (MRA) algorithm was used to filter the main regulatory genes in the inflammation-related pathway (GO:0006954). After obtaining the main regulatory genes, the expression of the main regulatory genes in the GSE32472, GSE125873, and GSE220135 datasets was detected. Through the logistic regression model, risk scoring was conducted for neonates, and the risk scores of non-BPD and BPD neonates were compared. Lastly, the classification performance of the model was evaluated using the area under the curve (AUC). The results showed that compared with non-BPD neonates, there were 486 up-regulated genes and 433 down-regulated genes in the peripheral blood mononuclear cells of BPD neonates. The inflammation-related pathway was highly enriched in the up-regulated genes. Ultimately, phospholipase C beta 1 (PLCB1), nidogen 1 (NID1), serum response factor binding protein 1 (SRFBP1), centrosomal protein 72 (CEP72), excision repair cross complementation group 6 like (ERCC6L), and peptidylprolyl isomerase like 1 (PPIL1) were identified as the main regulatory genes. The prediction model's calculation formula for risk score was PLCB1×0.26+NID1×0.97+SRFBP1×1.58+CEP72×(-0.36)+ERCC6L×2.14+PPIL1×0.67. The AUCs in the GSE32472 test dataset, GSE125873 dataset, and GSE220135 dataset were 0.88, 0.86, and 0.89, respectively. This prediction model could distinguish between non-BPD and BPD neonates. In conclusion, the prediction model based on inflammation-related pathway genes has a certain diagnostic value for BPD.

[Short-term efficacy and safety of cardiac contractility modulation in patients with heart failure].

Objective: To investigate the short-term efficacy and safety of cardiac contractility modulation (CCM) in patients with heart failure. Methods: This was a cross-sectional study of patients with heart failure who underwent CCM placement at the First Affiliated Hospital of Xinjiang Medical University from February to June 2022. With a follow-up of 3 months, CCM sensation, impedance, percent output, and work time were monitored, and patients were compared with pre-and 3-month postoperative left ventricular ejection fraction (LVEF) values, and 6-minute walk test distance and New York Heart Association (NYHA) cardiac function classification, and the occurrence of complications was recorded. Results: CCM was successfully implanted in all 9 patients. Seven(7/9) of them were male, aged (56±14) years, 3 patients had ischaemic cardiomyopathy and 6 patients had dilated cardiomyopathy. At 3-month postoperative follow-up, threshold was stable, sense was significantly lower at follow-up than before (right ventricle: (16.3±7.0) mV vs. (8.2±1.1) mV, P<0.05; local sense: (15.7±4.9) mV vs. (6.7±2.5) mV, P<0.05), and impedance was significantly lower at follow-up than before (right ventricle (846±179) Ω vs. (470±65) Ω, P<0.05, local sense: (832±246) Ω vs. (464±63) Ω, P<0.05). The CCM output percentage was (86.9±10.7) %, the output amplitude was (6.7±0.4) V, and the daily operating time was (8.6±1.0) h. LVEF was elevated compared to preoperative ((29.4±5.2) % vs. (38.3±4.3) %, P<0.05), the 6-minute walk test was significantly longer than before ((96.8±66.7)m vs. (289.3±121.7)m, P<0.05). No significant increase in the number of NYHA Class Ⅲ-Ⅳ patients was seen (7/9 vs. 2/9, P>0.05). The patient was not re-hospitalised for worsening heart failure symptoms, had no malignant arrhythmic events and experienced significant relief of symptoms such as chest tightness and shortness of breath. No postoperative complications related to pocket hematoma, pocket infection and rupture, electrode detachment, valve function impairment, pericardial effusion, or cardiac perforation were found. Conclusions: CCM has better short-term safety and efficacy in patients with heart failure.

Development of a 19-plex short tandem repeat typing system for individual identification and parentage testing of horses (Equus caballus).

Individual identification of horses for pedigree verification and registration is important for the sustainable development of the horse industry. Horse individual identification and parentage tests commonly use the 17 short tandem repeats (STRs) recommended by the International Society for Animal Genetics (ISAG) and the locus LEX33. While many multiplex STR typing systems have been established for the horse, a sex determining marker is usually absent, and none of them can simultaneously detect all 17 ISAG recommended loci and the locus LEX33. Here, we present a 19-plex STR typing system that contains the 17 ISAG recommend loci, the locus LEX33 and amelogenin as sex determining loci. The results of our sensitivity, species specificity, stutter analysis and population data analysis, indicate that this system is a specific, sensitive, and robust tool for the identification of individuals, parentage testing and genetic research in the horse.

[Roles of nurses in sleep medicine].

Sleep health becomes an important component of global public health. The incidence of sleep disorders is increasing rapidly worldwide, which seriously affects people's quality of life. In China, the lack of professional sleep physicians and technicians, the distribution of sleep centers and the unbalanced development of medical resources have seriously restricted the development of sleep medicine and the improvement of sleep health guarantee level. In Europe and America and other developed countries, sleep medicine has become a new interdisciplinary discipline. The development of nurses as sleep coordinator has become an irresistible trend. Nurses have been trained to become the main force of sleep technicians. These successful attempts in the field of sleep medicine provide reference for promoting the development of nursing care in China from the aspects of medical care, teaching and research.

[Clinical application and reflection of molecular biology technology in the tertiary prevention of birth defects].

Genetic factors are the main causes in occurrence of birth defects. With deep research in the field of genomics and application of molecular biology technology, the carrier status, fetal genetic variation and postpartum screening are respectively detected from pre-pregnancy, pregnancy and post-natal screening (before onset of disease) under perfect three-level prevention and control system for birth defects. Prospective detection, early diagnosis and intervention can prevent the occurrence of birth defects related to genetic diseases at multiple levels. This article describes and analyzes current clinical application and existing challenge of molecular biology techniques in prevention of birth defects related to genetic diseases.

[The association between the frequency of prenatal care in childbearing aged women and risk of small for gestational age among neonatal twins in Shaanxi Province].

Objective: To explore the association between the frequency of prenatal care in childbearing aged women and risk of small for gestational age (SGA) among neonatal twins in Shaanxi Province. Methods: From July to December 2013, a total of 30 027 childbearing aged women, who were pregnant from January 2010 to November 2013 and had definite outcomes, were selected from 30 districts (counties) of Shaanxi Province by using the multi-stage random sampling method. The questionnaires with a face-to-face survey method were used to retrospectively collect demographic information, pregnancy history, lifestyle during pregnancy, disease history, nutritional supplements, and health care during pregnancy. Information on the gestational age and birth weight of the newborn were obtained by consulting the medical certificate of birth and were registered as twin A and twin B by birth order. Finally, 356 childbearing aged women and their twin babies with complete data were included in the analysis. A generalized estimation equation model was used to analyze the association between the frequency of prenatal care and the risk of SGA among neonatal twins. Results: The age of childbearing aged women was (27.44±4.68) years old, of which 79.49% (283 women) were rural residents and 44.38% (158 women) had seven or more times prenatal care. The gestational age and birth weight were (37.64±2.51) weeks and (2 510±497) g, respectively. The prevalence of SGA was 51.40% (183/356) for twin A and 53.37% (190/356) for twin B, respectively. The prevalence of SGA was 44.30% (70/158) for twin A with seven or more times prenatal care and 42.41% (67/158) for twin B with seven or more times prenatal care, which was lower than that for twins with less than seven times prenatal care, respectively [57.07% (113/198) and 62.12% (123/198)] (P values were 0.017 and <0.001). The results of generalized estimation equation model suggested that compared to those with less than seven times prenatal care, after adjusting for parity, birth order, place of residence, maternal age, occupation, education, family wealth index, passive smoking, pregnancy-induced hypertension syndrome, folic acid, and iron supplement during perinatal period, and gender of the newborn, the OR (95%CI) of risk of SGA among childbearing aged women with seven or more times prenatal care was 0.60 (0.40-0.91). Conclusion: Seven or more times prenatal care could reduce the risk of SGA among neonatal twins in Shanxi Province.

Short communication: Genotyping and single nucleotide polymorphism analysis of bovine leukemia virus in Chinese dairy cattle.

Bovine leukemia virus (BLV) causes enzootic leucosis in cattle and is classified into 10 genotypes with a worldwide distribution, except for several European countries, Australia, and New Zealand. Although BLV is widespread in Chinese cows with the positive rate of 49.1% at the individual level, very little is known about the BLV genotype in dairy cattle in China. To determine BLV genetic variability in cows in China, 112 BLV-positive samples from 5 cities in China were used for BLV molecular characterization in this study. Phylogenetic analysis using the neighbor-joining method on partial env sequence encoding gp51 obtained from 5 Chinese cities and those available in GenBank (n = 53, representing BLV genotype 1-10) revealed the Chinese strains belonged to genotype 6. Seven unique SNP were identified among Yancheng, Shanghai, and Bengbu strains out of the total 12 SNP identified in Chinese strains. The genotyping coupled with SNP analysis of BLV can serve as a useful molecular epidemiological tool for tracing the source of pathogens. This study highlights the importance of genetic analysis of geographically diverse BLV strains to understand BLV global genetic diversity.

[Clinical significance of exosomal miR-1231 in pancreatic cancer].

Objective: To investigate the expression and clinical significance of exosomal miR-1231 in plasma of pancreatic cancer (PC) patients and pancreatic cancer cells. Methods: A total of 16 patients who were diagnosed with pancreatic cancer in Hunan Cancer Hospital were collected from April 2016 to August 2017. Meanwhile, 16 healthy volunteers were recruited as the healthy control group at the same period. The plasma exosomes were extracted, and the levels of miR-1231 were detected by qRT-PCR in PC and healthy control groups. Moreover, the clinicopathological significance of exosomal miR-1231 expression was analyzed. Furthermore, the expression of exosomal miR-1231 was detected in several pancreatic cancer cells (MIA PaCa-2, PANC-1, SW1990, AsPC-1 and BxPc-3) and two normal pancreatic epithelial cells (HPDE and human primary pancreatic epithelial cell). Results: qRT-PCR results showed that the expression level of miR-1231 in plasma exosomes of pancreatic cancer patients (1.06±0.46) was significantly lower than that in healthy controls (2.30±0.99; P<0.05). The levels of exosomal miR-1231 in patients with stage Ⅰ-Ⅱ (1.515±0.531), no distant metastasis (1.236±0.461) and no lymph node metastasis (1.337±0.522) were significantly higher than those with stage Ⅲ-Ⅳ (0.848±0.224), distant metastasis (0.757±0.278) and lymph node metastasis (0.838±0.261), respectively (P<0.05 for all). In addition, there were no correlation between exosomal miR-1231 expression and age, sex, smoking history, CA19-9 levels and tumor sites (P>0.05). Furthermore, the expression level of exosomal miR-1231 in pancreatic cancer cell lines (0.142±0.135) was significantly lower than that in normal epithelial cells (1.127±0.179; P<0.05). Conclusions: The downregulation of exosomal miR-1231 in plasma of pancreatic cancer patients and pancreatic cancer cells suggests that it is related to the initiation and development of PC. It may be a new diagnostic and prognostic marker for PC.

[The plasma level of amyloid-ß is associated with cognitive decline: a two years follow-up study in Xi'an rural areas].

Objective: To explore the relationship between plasma amyloid-ß (Aß) and cognitive decline during 2 year follow-up in a population-based cohort in Xi'an rural areas. Methods: The study was conducted in Qubao village in Xi'an suburbs cognitively normal residents over 40 years old were recruited from October 2014 to March 2015 and given a face-to-face standardized interview. Mini-mental state examination (MMSE) was employed to evaluate the global cognitive function, and quantification of plasma Aß was measured by sandwich enzyme-linked immunosorbent assay (ELISA) at baseline. Two years later, MMSE was tested at the end of study. Then logistic regression was performed to analyze the relationship between baseline Aß and cognitive change during 2 year follow-up. Results: A total of 1 020 participants completed the study, among whom 223 subjects (21.9%) presented MMSE scores decline (defined as MMSE scores decreased ≥2 points). Compared with those without decline, participants in the MMSE decline group were older (P<0.001) and had lower education level (P<0.001), while gender, hypertension, hyperlipemia, diabetes mellitus and APOE genotype were not significantly different between two groups. One-way analysis of variance (ANOVA) showed that the MMSE score decline was slighter in the lower tertile of baseline Aß(1)-40 compared with middle tertile (P=0.012), while MMSE decline were similar between different Aß(1)-42 level groups and Aß(1-42)/Aß(1-40) ratio groups (P=0.758, P=0.671, respectively). Multivariable logistic regression analysis showed that MMSE scores in the lower baseline plasma Aß(1-40) level declined more slowly (OR=0.565, 95%CI 0.379-0.845, P=0.005). However, the MMSE decline were also similar among different baseline plasma Aß(1-42) levels groups and Aß(1-42)/Aß(1-40) ratio groups. Conclusion: Population with lower level of baseline plasma Aß(1-40) manifests lower cognitive decline during 2 years, however further investigation on dynamics of plasma Aß and long term follow up are needed.

Interaction between the Wnt/ß-catenin signaling pathway and the EMMPRIN/MMP-2, 9 route in periodontitis.

BACKGROUND AND OBJECTIVES: In periodontitis, the Wnt/ß-catenin signaling pathway is related to the metabolism of the alveolar bone; further, extracellular matrix metalloproteinase inducer (EMMPRIN) expression is correlated with matrix metalloproteinases (MMPs) expression and inflammation severity. The aim of this study was to perform a preliminary investigation of the interaction between the Wnt/ß-catenin signaling pathway and the EMMPRIN/MMPs route in periodontitis. MATERIAL AND METHODS: Chronic periodontitis and healthy gingival tissues were obtained to detect the expression of Wnt3a, ß-catenin, EMMPRIN and MMP-2, 9 by using immunohistochemical analysis. The human immortalized oral epithelial cell/human gingival fibroblast direct co-culture model was treated with 10 µg/mL Porphyromonas gingivalis lipopolysaccharide (Pg. LPS). Anti-EMMPRIN antibody was used to block the effect of EMMPRIN. Dickkopf-1 (DKK-1) and Wnt3a were used as the inhibitor and activator of the Wnt/ß-catenin signaling pathway, respectively. Immunofluorescence was performed to visualize the localization of ß-catenin and EMMPRIN. Expression of the EMMPRIN, MMP-2, 9 and Wnt pathway's components was confirmed by western blotting and quantitative real-time polymerase chain reaction. RESULTS: Higher levels of Wnt3a, ß-catenin, EMMPRIN and MMP-2, 9 were observed in chronic periodontitis gingival tissues compared with controls. Pg. LPS significantly enhanced ß-catenin, p-GSK-3ß, EMMPRIN and MMP-2, 9 inductions in the human immortalized oral epithelial cell/human gingival fibroblast co-culture model. Anti-EMMPRIN antibody markedly reduced the expression of MMP-2, 9 only in the presence of Pg. LPS. Co-expression of ß-catenin and EMMPRIN was detected in the co-culture model. DKK-1 inhibited Wnt pathway, but upregulated the EMMPRIN/MMP-2, 9 routes. In contrast, activating Wnt pathway by Wnt3a repressed the EMMPRIN/MMP-2, 9 routes. The promotion effect of DKK-1 on MMP-2, 9 expressions was partially inhibited by the anti-EMMPRIN antibody. In addition, anti-EMMPRIN antibody led to a drastic decrease in ß-catenin and p-GSK-3ß. CONCLUSION: In periodontitis, EMMPRIN regulates MMP-2, 9 expressions, the activation of Wnt/ß-catenin signaling pathway downregulates the EMMPRIN/MMP-2, 9 routes and the blockade of EMMPRIN attenuates Wnt/ß-catenin signaling pathway.

Expressions and clinical significance of factors related to acute coronary syndrome.

Acute coronary syndrome (ACS) is the acute stage of coronary artery disease, which remains a major cause of mortality and morbidity. It is essential to explore the role of matrix metalloproteinase -2 (MMP-2) and interleukin (IL)-18 and their association with disease in patients with severe ACS. Circulating MMP-2 and IL-18 levels were measured using enzyme linked immunosorbent assay (ELISA) in 94 subjects with acute coronary syndrome (ACS, n=38), stable angina pectoris (SAP, n=27) and healthy individuals (control group, n=29). We examined the correlations between the levels of MMP-2 and IL-18 and cardiac risk factors in ACS. Logistic regression analysis was performed to screen for factors that predict ACS. Both MMP-2 and IL-18 concentrations were increased in the ACS group compared to the SAP group or control group (P less than 0.01). Especially, MMP-2 and IL-18 were highly expressed in the patients with ST elevated myocardial infarction (STEMI). Both serum levels of MMP-2 and IL-18 in the single-, double- and triple-vessel lesion group were higher compared to the control group (P less than 0.01). MMP-2 levels were positively correlated with IL-18 (r=0.639, P less than 0.01), CK-MB (r=0.47, P=0.003) and hs-CRP levels (r=0.583, P less than 0.01). The logistic regression analysis showed that increases in MMP-2 levels may be a powerful predictor of ACS. Thus, the changes in levels of serum MMP-2 and IL-18 may be useful in the diagnosis of ACS and prediction of its prognosis.

Gonorrhea infection increases the risk of prostate cancer in Asian population: a nationwide population-based cohort study.

This nationwide population-based retrospective cohort study evaluated the risk of developing prostate cancer among patients with gonorrhea. We identified cases of newly diagnosed gonorrhea in men between 2000 and 2010 from the Taiwan National Health Insurance Research Database. Each patient with gonorrhea was matched to four controls, based on age and index year. All subjects were followed up from the index date to December 31, 2010. The Cox proportional hazards regression model was used to assess the risk of prostate cancer. A total of 355 men were included in the study group, and 1,420 age-matched subjects without gonorrhea were included in the control group. After adjusting for age, comorbidities, urbanization level, hospital level, and monthly income, gonorrhea was significantly associated with an increased risk of prostate cancer (adjusted hazard ratio = 5.66, 95% confidence interval = 1.36-23.52). Men aged 45-70 years and those with lower monthly income were more strongly associated with prostate cancer in the study group than the control group. The higher risk for developing prostate cancer were also found in those without syphilis, without genital warts, without diabetes mellitus, without chronic obstructive pulmonary disease, without benign prostatic hypertrophy, without chronic prostatitis, and without alcoholism. The Kaplan-Meier analysis showed the risk of prostate cancer was significantly higher in the study group than in the control group. Gonorrhea may be involved in the development of prostate cancer. More intensive screening and prevention interventions for prostate cancer should be recommended in men with gonorrhea.

Helicobacter pylori infection increases the risk of adult-onset asthma: a nationwide cohort study.

Helicobacter pylori infection (HPI) appears to reduce risk of childhood-onset asthma, but the relationship between HPI and adult-onset asthma is inconclusive. This study explored the potential association between HPI and risk of adult-onset asthma. We conducted a national insurance retrospective cohort study using the longitudinal health insurance database (LHID 2000) in Taiwan. We enrolled the HPI group consisting of 1664 patients with HPI diagnosis between 2000 and 2007, and the non-HPI group consisting of 6,656 age- and sex-matched subjects without HPI. All study participants had been followed up from index date to the diagnostic date of asthma, withdrawal from the National Health Insurance program, or the end of 2011, which came first. We analyzed risk of adult-onset asthma with respect to sex, age, and comorbidities by using Cox models. Cigarette smoking status, which could not be obtained from the program, was adjusted indirectly by considering chronic obstructive pulmonary diseases in our statistical models because the disease is related to heavy smoking. After adjustment for sex, age, and comorbidities, HPI was significantly associated with an increased 1.38-fold risk of adult-onset asthma. Moreover, among people without comorbidities, the 1.85-fold risk of adult-onset asthma remained higher for the HPI population compared with the non-HPI population. In this study, patients with HPI exhibited a significantly higher risk of adult-onset asthma than did the subjects without HPI.

Quantum behavior of water nano-confined in beryl.

The proton mean kinetic energy, Ke(H), of water confined in nanocavities of beryl (Be3Al2Si6O18) at 5 K was obtained by simulating the partial vibrational density of states from density functional theory based first-principles calculations. The result, Ke(H) = 104.4 meV, is in remarkable agreement with the 5 K deep inelastic neutron scattering (DINS) measured value of 105 meV. This is in fact the first successful calculation that reproduces an anomalous DINS value regarding Ke(H) in nano-confined water. The calculation indicates that the vibrational states of the proton of the nano-confined water molecule distribute much differently than in ordinary H2O phases, most probably due to coupling with lattice modes of the hosting beryl nano-cage. These findings may be viewed as a promising step towards the resolution of the DINS controversial measurements on other H2O nano-confining systems, e.g., H2O confined in single and double walled carbon nanotubes.

A first-principles study of the diffusion coefficients of alloying elements in dilute α-Ti alloys.

Using first-principles calculations accompanied by the transition state theory and an 8-frequency model, we present a comprehensive investigation of the diffusion coefficients of substitutional alloying elements X in dilute α-Ti alloys, where X denotes Al, V, Nb, Ta, Mo, Zr, and Sn. The alloying elements Mo and Al exhibit a maximum and a minimum diffusion rate in dilute α-Ti alloys, respectively. It is found that the nearest-neighbor solute-vacancy binding energies and activation energies are roughly inversely proportional to the volume changes induced by solute atoms. There are two exceptions to this trend: Al and Mo. Besides the physical effect (i.e., solute size), two other key factors governing solute diffusion in dilute α-Ti are clarified: the chemical bonding characteristics and vibrational features of X-Ti pairs. It verifies that the ultrafast diffusivity of Mo arises from the interactions with Ti atoms by metallic bonds and its low-frequency contributions to lattice vibration, while the more covalent bonding nature and the high-frequency contributions to the lattice vibration of Al lead to its ultraslow diffusivity. In addition, the correlation effects of diffusion coefficients are non-negligible for the large solutes Ta, Nb, and Zr, in which the direct solute-vacancy migration barriers are much smaller than the solvent-vacancy migration barriers.

On the mean kinetic energy of the proton in strong hydrogen bonded systems.

The mean atomic kinetic energies of the proton, Ke(H), and of the deuteron, Ke(D), were calculated in moderate and strongly hydrogen bonded (HB) systems, such as the ferro-electric crystals of the KDP type (XH2PO4, X = K, Cs, Rb, Tl), the DKDP (XD2PO4, X = K, Cs, Rb) type, and the X3H(SO4)2 superprotonic conductors (X = K, Rb). All calculations utilized the simulated partial phonon density of states, deduced from density functional theory based first-principle calculations and from empirical lattice dynamics simulations in which the Coulomb, short range, covalent, and van der Waals interactions were accounted for. The presently calculated Ke(H) values for the two systems were found to be in excellent agreement with published values obtained by deep inelastic neutron scattering measurements carried out using the VESUVIO instrument of the Rutherford Laboratory, UK. The Ke(H) values of the M3H(SO4)2 compounds, in which the hydrogen bonds are centro-symmetric, are much lower than those of the KDP type crystals, in direct consistency with the oxygen-oxygen distance ROO, being a measure of the HB strength.

Management of Valsa Canker on Apple with Adjustments to Potassium Nutrition.

Valsa canker, caused by the fungus Valsa mali, is one of the most destructive diseases of apple in the primary production areas of China and other East Asian countries. Currently, there are no effective control methods for this disease. We investigated the occurrence of Valsa canker in 24 apple orchards in Shaanxi Province in concert with foliar nutrient analysis, and found that there was a significant negative correlation of leaf potassium (K) content with incidence and severity of Valsa canker. Fertilization experiments showed that increasing tree K content enhanced resistance to pathogen colonization and establishment. Apple trees with leaf K content greater than 1.30% exhibited almost complete resistance to Valsa mali. Field trials demonstrated that increasing K fertilization could significantly reduce disease incidence. Improved management of tree nutrition, especially K content, could effectively control the occurrence and development of Valsa canker.

[Stress distribution and deformation of uterosacral ligament and cardinal ligament under different working conditions simulated by the finite element model].

OBJECTIVE: To establish the finite element model of uterosacral ligament (USL) and cardinal ligament (CL) and analyze the stress distribution and deformation with USL and CL under different working conditions. METHODS: Patients with stage Ⅲ-Ⅳ pelvic organ prolapse (POP) and healthy female volunteers were selected for research subject, and divided into anterior uterus group and posterior uterus group. Two POP patients and two volunteers were selectd into the anterior uterus group and posterior uterine group respectively. Pelvic MRI scan was performed in two groups. Based on the original MRI data sets, the finite element model of USL and CL was constructed by using the software such as the Mimics, and the stress distribution and deformation of USL and CL were simulated. RESULTS: Under the premise of the elastic modulus fixed and three different working conditions such as 60 cmH2O, 99 cmH2O and 168 cmH2O (1 cmH2O=0.098 kPa) with abdominal pressure generated by maximum Valsalva maneuver, according to the present conditions and the simulation, the trend was analyzed: the stress and deformation of the uterus, anterior vaginal wall, USL and CL in two groups were mainly distributed in the middle and lower part of the anterior vaginal wall or the ligament and the cervix-vagina junction, the maximum stress and the maximum displacement were mainly concentrated in the lower region of the anterior vaginal wall. With increasing of abdominal pressure generated by the maximum Valsalva maneuver, the maximum stress values of the POP patient in anterior uterus group under three different working conditions were: 0.027 9, 0.046 0, 0.078 0 MPa, and the maximum displacement values were: 9.145 5, 15.090 0, 25.607 0 mm. The maximum stress values of the volunteer in anterior uterus group under three different working conditions were: 0.012 6, 0.020 8, 0.035 3 MPa, and the maximum displacement values were: 1.816 7, 2.997 5, 5.086 7 mm. The maximum stress values of the POP patient in posterior uterine group under three different conditions were: 0.069 4, 0.114 6, 0.194 5 MPa, and the maximum displacement values were: 11.658 0, 19.236 0, 32.643 0 mm. The maximum stress values of the volunteer in posterior uterus group under three different working conditions were: 0.009 1, 0.015 1, 0.025 6 MPa, and the maximum displacement values were: 2.581 6, 4.259 6, 7.228 4 mm. The maximum stress values and the maximum displacement values were all increased with increasing of abdominal pressure in the two groups. The maximum stress values and the maximum displacement values of the POP patients were greater than those of volunteers. Under different working conditions, the maximum stress values and maximum displacement values of the posterior uterus POP patient were all greater than those of the anterior uterus POP patient. CONCLUSIONS: The finite element model of USL and CL is completely based on the MRI technology and the model is real and reliable. The increase of abdominal pressure will produce a larger stress and deformation of USL and CL, which is one of the reasons causing the injury of the ligament.