[Comparison of pulmonary vascular tortuosity and fractal dimension in patients with chronic thromboembolic pulmonary disease and chronic thromboembolic pulmonary hypertension].

Objective: To compare the differences in pulmonary vascular morphological parameters between patients with chronic thromboembolic pulmonary disease (CTEPD) and chronic thromboembolic pulmonary hypertension(CTEPH), and to explore the value of pulmonary artery morphology in the differential diagnosis of CTEPD and CTEPH. Methods: Thirty-nine patients with CTEPH [14 males, 25 females, mean age: (54.1±12.4) years] and 29 patients with CTEPD [10 males, 19 females, mean age: (51.4±18.0) years] from January 2018 to December 2020 were retrospectively included. The pulmonary artery and vein tree was segmented from the computed tomography pulmonary angiography (CTPA) images, and the morphological parameters of pulmonary vessels including the number of pulmonary arteries, pulmonary arterial tortuosity(distance metric, DM) and fractal dimension (FD), were calculated. The differences in pulmonary vascular morphological parameters between the two groups were compared, and the correlation between morphological parameters and hemodynamics was analyzed. Results: There was no significant difference in gender and age between CTEPH and CTEPD groups (χ2=0.015,P=0.904 & t=-0.729, P=0.469). The number of pulmonary arteries in CTEPH group (n=249.43±76.27) was significantly lower than that in CTEPF group (n=298.79±78.11, t=2.612, P=0.011). The pulmonary arterial tortuosity in CTEPH group (DM=1.26±0.17) was significantly higher than that in CTEPD group (DM=1.17±0.10, t=3.516, P=0.002). There was no significant difference in FD between CTEPH and CTEPD (FD=3.01±0.21 & 3.08±0.22, t=1.359, P=0.179). The number of pulmonary arteries was negatively correlated with pulmonary vascular resistance (r=-0.325, P=0.026). Pulmonary arterial tortuosity was positively correlated with mean pulmonary artery pressure (r=0.387,P=0.017), and was positively correlated with pulmonary vascular resistance (r=0.647, P<0.001). Conclusion: Pulmonary artery curvature is an important morphological parameter in differentiating CTEPH from CTEPD, and is related to mean pulmonary artery pressure and pulmonary vascular resistance.

[Advances in the epidemiology of chronic thromboembolic pulmonary hypertension].

The early symptoms of chronic thromboembolic pulmonary hypertension (CTEPH) are not specific, and there is a high rate of misdiagnosis, missed diagnosis, and lack of awareness among clinicians. Understanding the current epidemiological characteristics of CTEPH is helpful to raise the understanding level of Chinese clinicians on CTEPH and improve the current status of prevention and treatment. However, epidemiological information and relevant reviews on CTEPH are currently lacking in China. In this review, we combined the published epidemiological literature on CTEPH in the real world, summarized the research overview, prevalence, incidence, survival rate and risk factors of CTEPH, and provided an outlook for the development of multicenter and high-quality CTEPH epidemiological research in China.

[Clinical features and CT findings of fibrosing mediastinitis associated pulmonary hypertension].

Objective: To investigate the clinical features and CT findings of pulmonary hypertension (PH) in patients with fibrosing mediastinitis (FM). Methods: Thirteen patients with FM diagnosed between September 2015 and June 2022 were studied retrospectively, including patients with PH (FM-PH group) and patients without PH (FM group) confirmed on right heart catheterization. The t test of two independent samples, Mann-Whitney U rank sum and Fisher's test were used to compare the general information, symptoms, laboratory examination, right ventricular and pulmonary artery measurement data and pulmonary artery CT findings between the two groups, respectively. Results: Compared with the 7 FM patients aged 28-79 (60.00±17.69) years, the 6 patients in the FM-PH group, aged from 60 to 82 (68.83±8.35) years, had more peripheral edema, lower percentage of PaO2, wider inner diameters of pulmonary artery and right ventricle, a higher ratio of right ventricle and left ventricular transverse diameter, faster tricuspid regurgitation velocity and higher estimated systolic pulmonary artery pressure (P<0.05). There were no differences in BNP levels and tricuspid annular plane systolic excursion between groups (P>0.05). Of the 6 patients with PH, 5 had precapillary PH and 1 had mixed PH. Except that the pulmonary vascular resistance in patients of the FM-PH group was significantly higher than that in the FM group (P<0.05), there were no significant differences in cardiac output, mixed venous oxygen saturation and pulmonary capillary wedge pressure between the two groups. CT pulmonary angiography (CTPA) showed pulmonary artery and vein stenosis. Patients in the FM-PH group had more severe stenosis and occlusion of pulmonary artery and pulmonary vein (P<0.05), and more involvement of multiple pulmonary veins (P<0.05). Conclusions: The clinical manifestation of FM complicated with PH is related to the degree of involvement of pulmonary artery, vein and airway. It is recommended that the disease be evaluated in combination with multiple parameters such as clinical manifestations, cardiac ultrasound, right cardiac catheter and CTPA.

[Rescue balloon pulmonary angioplasty for a patient with acute exacerbation of chronic thromboembolic pulmonary hypertension supported by extracorporeal membrane oxygenation: a case report].

A 33-year-old male patient was admitted to hospital because of "dyspnea after activity for 3 years and aggravation for 15 days". With a history of membranous nephropathy, irregular anticoagulation led to acute exacerbation of Chronic thromboembolic pulmonary hypertension(CTEPH) and acute respiratory failure, and endotracheal intubation and mechanical ventilation was given. Although treated with thrombolysis and adequate anticoagulation, the condition worsened and hemodynamics deteriorated, and then VA-ECMO was performed. Due to severe pulmonary hypertension and right heart failure,ECMO could not be weaned off, and the patient subsequently developed pulmonary infection, right lung hemorrhage, hyperbilirubinemia, coagulation dysfunction and other complications. Then the patient was transferred to our hospital by airplane, and multidisciplinary discussions were quickly arranged after admission. Considering that the patient was critically ill and complicated with multiple organ failure, pulmonary endarterectomy (PEA) could not be tolerated, rescue balloon pulmonary angioplasty (BPA) was recommended and performed on the second day after admission. The mean pulmonary artery pressure was 59 mmHg(1 mmHg=0.133 kPa) measured by right heart catheterization, and pulmonary angiography showed that the main pulmonary artery was dilated, while the right lower pulmonary artery was completely occluded, and there were multiple stenoses in the branches of the right upper lobe, middle lobe pulmonary artery and the left pulmonary artery. BPA was performed on a total of 9 pulmonary arteries. VA-ECMO was weaned off on day 6 after admission, and the mechanical ventilation was weaned off on day 41 after admission. The patient was successfully discharged on day 72 after admission. Rescue BPA was an effective treatment for severe CTEPH patients who could not be treated with PEA.

[Annual review of venous thromboembolism in 2022].

Venous thromboembolism (VTE) includes pulmonary thromboembolism (PTE) and deep venous thrombosis (DVT). The mortality rate of PTE in China is comparable to the international level, accounting for a significant portion of the global disease burden and a major aspect of respiratory diseases. The research on VTE has made rapid progress in recent years, especially in the VTE prevention, diagnosis strategy, risk stratification, treatment guideline, poor prognosis and complications. Researchers have gradually realized that VTE is a chronic disease involved multi-system. It still needs to be further standardized about the complete flow scheme of the VTE. The article reviewed the latest progress in the field of VTE in the previous year, aiming to provide more medical evidence for the future.

[The first outbreak of dengue fever and molecular tracing in Puyang, 2019].

Objective: This study retrospectively analyzed an outbreak of dengue fever in Puyang of Henan province in 2019, in order to find the sources of infection. Methods: Dengue virus IgM/IgG and NS1 antigen were tested by colloidal gold method. E gene was amplified by PCR. MegaX was used for sequences alignment to construct evolutionary distance trees. Results: After clinical and laboratory confirmation, there were 81 cases of dengue fever, 17 of which were imported case who were local farmers and worked in Combadia and Thailand, and 64 of which were indigenous cases. The E gene alignment results showed that the pathogen of this epidemic was Vietnamese 1 and highly homologous with the Vietnamese strain. After the local outbreak, dengue virus E gene developed a nucleotide site mutation which can be steadily transmission. Conclusion: The dengue fever outbreak in Puyang was a local outbreak caused by dengue virus type 1, which was associated with imported cases. Gene sequencing showed that the imported pathogen had a relatively stable and transmissible nucleotide mutation after the local epidemic.

[Awareness and management of chronic thromboembolic pulmonary hypertension among respiratory physicians revealed by a questionnaire analysis].

Objective: To evaluate the awareness and management status of chronic thromboembolic pulmonary hypertension (CTEPH) among respiratory physicians and therefore to provide for establishing clinical guidelines on CTEPH. Methods: A questionnaire was designed to address the common questions in CTEPH management. The responses were collected online and the data were analyzed. Totally, 1 038 valid questionnaires were collected. Results: 74.1% of the responders were from tertiary hospitals and 88.5% were attending physicians. Only a few hospitals could carry out ventilation-perfusion scintigraphy (31.3%) and right heart catheterization (38.5%). For the treatment of CTEPH, pulmonary endarterectomy and balloon pulmonary angioplasty (BPA) were only performed in 8.0% and 10.4% of the hospitals respectively, and mostly in tertiary hospitals, P<0.01. 49.6% of the physicians were familiar with the interpretation of CTPA, while only 19.9% of V/Q scan. 88.5% of the physicians choose CTPA as the screening tool for CTEPH, but only 3.9% were consistent with the guidelines. 79% of the physicians agreed with lifelong anticoagulation for CTEPH, and 70.8% supported operability should be evaluated in all CTEPH patients. Conclusions: This questionnaire study showed that there was a gap between the guidelines and the real world practice in CTEPH management. Efforts should be made to improve the awareness and standardization of the management of CTEPH.

[Imaging findings of CT pulmonary angiography in patients with chronic thromboembolic pulmonary hypertension].

Objective: To investigate the imaging findings of CT pulmonary angiography (CTPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH). Methods: Consecutive CTEPH cases admitted to receive CTPA in China-Japan Friendship Hospital from December 2015 to December 2019 were enrolled with prospective data collected. The medical histories, imaging manifestation and hemodynamic parameters were analyzed. Patients were divided into proximal lesions group and distal lesions group according to the site of thrombus, and imaging findings were compared between these two groups. Results: In 135 cases of CTEPH, CTPA showed thrombus in both lungs in the majority of patients (133 cases, 98.5%) with location of thromboembolic disease in level Ⅰ, Ⅱ and Ⅲ for most patients, only 8 cases with level Ⅳ(7.3%) and no level 0 patients. The most common signs of chronic thrombus were vessel cutoffs (134 cases, 99.3%), eccentric wall-adherent filling defects (111 cases, 88.2%), web or bands (80 cases, 59.3%), stenosis (41 cases, 30.4%). Compared to patients with distal lesions, eccentric wall-adherent filling defects, irregular vessel wall were more common in patients with proximal lesions, stenosis was more common in distal lesions, all P<0.05. The most common lung parenchymal signs were mosaic attenuation (104 cases, 77.0%), and pulmonary infarction (79 cases, 58.5%). Pulmonary infarction included pleura-based consolidation opacity (35/79, 44.3%), linear opacities (23/79, 29.1%), or both (13/79, 16.5%). Pulmonary artery enlargement (132 cases, 97.8%) and right ventricular hypertrophy (130 cases, 96.3%) were common, other signs included contrast reflux into the inferior vena cava (70 cases, 51.9%), enlargement of bronchial arteries (68 cases, 50.3%). No differences were found for all the secondary signs between patients with proximal lesions and those with distal lesions, all P>0.05. Conclusions: Vessel cutoffs, eccentric wall-adherent filling defects, web or bands are the most common CTPA findings of chronic thrombus in CTEPH. Secondary signs include mosaic attenuation, pulmonary infarction, pulmonary artery enlargement, right ventricular hypertrophy and enlargement of bronchial arteries. Eccentric wall-adherent filling defects are more common in patients with proximal lesions than those with distal lesions.

[Detection of right-to-left shunt with transthoracic contrast echocardiography in patients with pulmonary hypertension].

Objective: To explore the value of right heart contrast echocardiography in etiological diagnosis and severity assessment of pulmonary hypertension (PH). Methods: A retrospective analysis was conducted on 74 patients who underwent transthoracic contrast echocardiography in China-Japan Friendship Hospital from May 2015 to July 2018, all of whom were diagnosed as PH by right heart catheterization. Patients were divided into three groups according to contrast echocardiography: the intra-cardiac shunt group (<4 cardiac cycles with microbubbles in the left heart); Intrapulmonary shunt group (>4 cardiac cycles with microbubbles in the left heart); non-shunt group. The etiology, partial arterial oxygen pressure (PO(2)), N-terminal pro-brain natriuretic peptide (NT-proBNP), mean pulmonary artery pressure (mPAP), right atrial pressure (RAP), pulmonary vascular resistance (PVR) and cardiac output (CO) were analyzed. Central nervous system complications were also compared among the three groups. Results: Among the 74 patients, right-to-left shunt was found in 28 cases (37.8%) by contrast echocardiography, including 11 cases (14.9%) of intra-cardiac shunt and 17 cases (23.0%) of intrapulmonary shunt. In the 11 cases of intra-cardiac shunt, 7 were diagnosed with congenital heart disease and 4 were patent foramen. Two with hereditary hemorrhagic telangiectasia (HHT) and 1 with pulmonary arteriovenous malformation (PAVM) were included in the 16 cases of intrapulmonary shunt. There was no statistical difference in PO(2), mPAP, PVR, NT-proBNP, RAP, CO and functional class among the three groups (all P>0.05). A total of 5 cases (6.8%) were found with nervous system comorbidities, 4 cases (5.4%) with cerebral infarction and 1 cases epilepsy, and 2 cases of cerebral infarction were diagnosed as paradoxical embolism. Nervous system complications were more common in patients with intra-cardiac shunt than in other groups. Conclusion: While right-to-left shunt detected by contrast echocardiography has no relationship with disease severity, it has complementary value in the etiological diagnosis of PH, and intra-cardiac shunt may increase the risk of nervous system complications.

[Clinical characteristics of patients with antisynthetase syndrome and interstitial pulmonary disease].

Objective: To provide reference for clinicians in diagnosis and treatment of antisynthetase syndrome with interstitial pulmonary disease (ASS-ILD) by analyzing the clinical features, imaging features and pulmonary function changes of ASS-ILD patients. Methods: A total of 92 patients with ASS-ILD diagnosed in the Respiratory Center of China-Japan Friendship Hospital from January 2015 to May 2018 were included, clinical manifestations, high-resolution computed tomography (HRCT), pulmonary function test, treatment and outcome were retrospectively analyzed. Results: The average age of the 92 patients was (58.6±12.2) years with a ratio of male to female 1∶1.79. The main types of anti-synthetase antibody were anti-Jo-1 antibody (37 cases, 40.2%) and anti EJ antibody (26 cases, 28.3%). The most common symptoms of ASS-ILD were cough (79 cases, 85.9%), shortness of breath (60 cases, 65.2%), expectoration (54 cases, 58.7%), fever (34 cases, 36.9%), and common signs were craftsman's hand (30 cases, 32.6%) and joint pain (23 cases, 25.0%). The most common imaging findings in HRCT were ground-glass opacities(68 cases, 73.9%), reticulations (45 cases, 48.9%), tractive bronchiectasis (40 cases, 43.5%) and consolidation (39 cases, 42.4%). The most common types of ILD were non-specific interstitial pneumonia (NSIP) (63 cases, 68.5%), followed by NSIP-organic pneumonia (OP) (12 cases, 13.0%). The main type of lung function impairment was mild restrictive ventilation dysfunction. There were no significant differences in clinical features, imaging findings and pulmonary function changes in different subtypes of ASS-ILD patients (all P>0.05). Corticosteroids was used in 78 (84.8%) of ASS-ILD patients, and 34 cases (37.0%) were given cyclophosphamide. A total of 91 patients (98.9%) were discharged with improvement and 1 anti-EJ positive patient died. Conclusions: ASS-ILD occurs frequently in middle-aged and old women. Respiratory symptoms, craftsman's hands and arthritis are the most common clinical manifestations. The most common imaging types of ILD are NSIP and NSIP-OP. Corticosteroids is commonly used for treatment.

[Risk factors and clinical features of hospital-associated venous thromboembolism].

Objective: To investigate the clinical features and risk factors of hospital-associated venous thromboembolism (VTE). Methods: The study enrolled acute VTE patients admitted into China-Japan Friendship Hospital from January 1, 2017 to December 31, 2017. The hospital-associated VTE (HA-VTE) group and the community-associated VTE (CA-VTE) group were classified according to whether the VTE occurred during hospitalization or within a 90-day period of admission to hospital (including inpatient with at least two days of hospital stay or a surgical procedure under general or regional anaesthesia). Differences in clinical features, risk factors, and mortality rate were compared between the two groups. Results: A total of 437 patients with acute VTE were analyzed in the study. Among them, 266 patients were HA-VTE, 171 patients were CA-VTE. Patients in the CA-VTE group were more likely to have varicose veins, sedentary, long-distance travel, and patients in the HA-VTE group were more complicated with recent surgery (<1 month), bed rest, active malignant tumor, acute infections, acute cerebral infarction, fracture, central venous catheter (P<0.05). The CA-VTE group had more clinical symptoms such as lower extremity pain, dyspnea, chest pain and chest tightness (P<0.05). HA-VTE patients had less clinical symptoms but were more severe than the CA-VTE patients, with more sudden deaths (0 vs 3.4%, P=0.035). Among HA-VTE patients, 92.8% experienced VTE during hospitalization or within 1 month of the preceding hospital encounter, with a 13-day median time to VTE. The all-cause mortality rate was higher for HA-VTE group than CA-VTE group (8.3% vs 1.2%, P<0.001), and the in-hospital VTE was more common compared to VTE diagnosed post-discharge (12.2% vs 3.4%, P<0.001). Conclusions: More than half events of VTE are related to recent hospitalizations. HA-VTE has different risk factors from CA-VTE, combined with fewer clinical symptoms but higher all-cause mortality rate. More attention about VTE should be paid to hospitalized patients to reduce the incidence of HA-VTE events.

[Efficacy and safety of Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension].

Objective: To study the efficacy and safety of Balloon pulmonary angioplasty (BPA) for chronic thromboembolic pulmonary hypertension (CTEPH). Methods: Patients who were diagnosed CTEPH in China-Japan Friendship Hospital from Feb 2018 to Sep 2019 were evaluated. The ineligibility for pulmonary endarterectomy (PEA) and the indication for BPA were decided on the basis of a consensus among the multidisciplinary team for all CTEPH patients. 6-min walk distance (6MWD), the plasma level of N-terminal pro-brain natriuretic peptide (NT-proBNP), mixed venous oxygen saturation, mean pulmonary artery pressure (mPAP), cardiac index (CI) and pulmonary vascular resistance (PVR) were collected and analyzed before the first and the last BPA session. Results: A total of 67 BPA sessions were performed for 302 subsegmental pulmonary arteries in 25 inoperable CTEPH patients. 10 males (40.0%) and 15 females (60.0%), with the age of (57.8±7.1) years old. The median interval between CTEPH diagnosis and first BPA was 20.0 (9.0, 48.5) months. 18 patients were received more than 2 BPA sessions, the median follow-up time was 5.0 (3.5, 8.3) months. 6MWD, CI and the mixed venous oxygen saturation were significant improved after BPA [(425±74) vs (345±109) m, (1.99±0.45) vs (1.62±0.35) L·min(-1)·m(-2), (68.1%±6.5%) vs (61.2%±6.3%)](all P<0.05). The plasma level of NT-proBNP, mPAP and PVR were significantly decreased after BPA [259 (93, 739) vs 806 (148, 2 159) ng/L, (40.6±8.3) vs (47.3±10.7) mmHg (1 mmHg=0.133 kPa), (11.9±4.9) vs (17.2±6.5) WU (1 WU=80 dyn·s·cm(-5))](all P<0.05). Hemoptysis occurred in 5 sessions (7.5%) and reperfusion pulmonary edema (RPE) occurred in 2 sessions (1.5%), 1 patient needed non-invasive mechanical ventilation because of RPE, 1 patient died from right heart failure caused by hemoptysis during perioperative period. Conclusions: BPA can significantly improve the exercise tolerance and hemodynamic parameters for inoperable CTEPH patients, the risks of BPA are acceptable. BPA is an effective and relatively safe treatment for inoperable CTEPH patients.

[Clinical characteristics of patients with chronic thromboembolic pulmonary hypertension].

Objective: To investigate the clinical characteristics of patients with chronic thromboembolic pulmonary hypertension (CTEPH). Methods: CTEPH cases consecutively admitted into China-Japan Friendship Hospital from September 2015 to June 2019 were enrolled with prospective data collection. The medical histories, clinical characteristics, laboratory tests, imaging manifestation and hemodynamic parameters were analyzed. Patients were divided into high pulmonary vascular resistance (PVR) group and low PVR group according to the PVR level>1 000 dyn·s·cm(-5) or not, and clinical characteristics were compared between these two groups. Results: In the 148 cases of CTEPH, right heart catheterization was performed in 103 cases with mPAP (45.1±11.0) mmHg and PVR of (992±430) dyn·s·cm(-5). At diagnosis, 88 (59.5%) cases were in WHO functional class Ⅲ and 27 (18.2%) in class Ⅳ. Most common presenting symptoms were dyspnea (147, 99.3%), chest tightness (68, 45.9%), hemoptysis (42, 28.3%), syncope (30, 20.3%), and most common signs were P2 accentuation (95, 64.9%), edema (65, 43.9%), cyanosis (47, 31.8%), systolic murmur (44, 29.7%) and jugular vein distention (35, 23.6%). In 103 cases with right heart catheterization, 52 were in the low PVR group and 51 in high PVR group. Compared to the low PVR group, high PVR group patients had higher WHO functional class and more jugular vein distention (both P<0.05). In all the 148 cases, previous venous thromboembolism (VTE) was confirmed in 105 (70.9%) patients, with a higher prevalence of previous VTE in low PVR group than that in high PVR group (P<0.001). 30 (20.3%) patients had varicose veins of the lower extremities, and 21 (14.2%) had other thrombophilic disorders including antiphospholipid syndrome, protein C and S deficiency and antithrombin Ⅲ deficiency. Conclusions: Dyspnea, P2 accentuation and edema are the most common clinical presentation of CTEPH. Previous history of VTE is common in CTEPH patients with thrombophilia in some cases.

[Brain protection strategy and effectivity in pulmonary thromboendarterectomy].

Objective: To summarize the experience and effectivity of brain protection in 25 patients who suffered from chronic thromboembolic pulmonary hypertension (CTEPH) and received pulmonary thromboendarterectomy (PTE) under deep hypothermic circulatory arrest. Methods: Retrospective analysis of 25 PTE surgeries in our center from December 2016 to August 2018. All cases were completed underdeep hypothermic circulatory arrest. Standard brain protections were strictly executed, including: balanced and controlled extracorporeal circulation cooling, cerebral oxygen saturation (rSO(2)) monitoring, strictly control of circulatory arrest time, and etc. The neurological adverse events during the perioperative period were recorded and statistically analyzed, and the intelligence level and cognitive function of the patients were evaluated by MMSE scale and MoCA scale before surgery and discharge. Results: All the 25 patients successfully completed the surgery, and 1 patient (4%) died of postoperative infection. The mean pulmonary arterial pressure decreased from (52.9±16.7) mmHg before surgery to (23.6±8.1) mmHg immediately after surgery (t=10.01, P<0.01), and(20.7±7.9) mmHg at 3 months follow-up (t=10.73, P<0.01). Pulmonary vascular resistance decreased from 975.4 (788.6-1 292.8) dyn·s·cm(-5) to 376.1 (283.6-565.5) dyn·s·cm(-5) (Z=5.34, P<0.01). Neurological complications occurred in 3 patients during the perioperative period, including 2 patients with hypoxic encephalopathy, and 1 patient with cerebral hemorrhage. All 3 patients fully recovered before discharge. Univariate analysis showed that the duration of rSO(2)<40% and the maximum decrease rate of rSO(2) from baseline were significantly correlated with postoperative neurological damage. Multivariate analysis showed only time of rSO(2)<40% was significantly correlated with postoperative neurological damage. There was no significant difference in MMSE and MoCA score before and after surgery (P>0.05). Conclusions: Adequate brain protection measures are essential to reduce the neurological complications of PTE surgery. Real-time intraoperative monitoring of rSO(2) and strict control of circulatory arrest time can further reduce the occurrence of neurological damage.

High polymorphism at microsatellite loci in the Chinese donkey.

To reveal the genetic diversity and phylogenetic relationships between Chinese donkey breeds, 415 individuals representing ten breeds were investigated using ten microsatellite markers. The observed number of alleles, mean effective number of alleles (NE), mean expected heterozygosity (HE), and polymorphic information content (PIC) of each breed and polymorphic locus were analyzed. The results showed that seven (HTG7, HTG10, AHT4, HTG6, HMS6, HMS3, and HMS7) of ten microsatellite loci were polymorphic. The mean PIC, HE, and NE of seven polymorphic loci for the ten donkey breeds were 0.7679, 0.8072, and 6.0275, respectively. These results suggest that domestic Chinese donkey breeds possess higher levels of genetic diversity and heterozygosity than foreign donkeys. A neighbor-joining tree based on Nei's standard genetic distance showed that there was close genetic distance among Xinjiang, Qingyang, Xiji, and Guanzhong donkey breeds. In addition, Mongolia and Dezhou donkey breeds were placed in the same category. The phylogenetic tree revealed that the genetic relationships between Chinese donkey breeds are consistent with their geographic distribution and breeding history.

The dependence of extracted current on discharge gas pressure in neutral beam ion sources on HL-2A tokamak.

The discharge gas pressure is a key factor to influence the extracted current of ion source. In this paper, the dependence of extracted current on discharge gas pressure was investigated in detail at different arc discharge currents. The discharge gas pressure with a very broad range (0.1 Pa-2.7 Pa) was scanned for the first time. It is turned out that, with the increasing of discharge gas pressure, the extracted current increases and the arc voltage decreases at different arc currents; however, when the discharge gas pressure exceeds a certain value, the extracted current decreases. For the same discharge gas pressure, the higher the arc current, the higher the arc voltage and the extracted current are. The arc efficiency was also calculated, and its dependence on gas pressure was almost the same with the dependence of extracted current on gas pressure, but at the same discharge gas pressure, the lower the arc current, the higher the arc efficiency is and the lower the extracted current is.

Multiple maternal origins of native modern and ancient horse populations in China.

To obtain more knowledge of the origin and genetic diversity of domestic horses in China, this study provides a comprehensive analysis of mitochondrial DNA (mtDNA) D-loop sequence diversity from nine horse breeds in China in conjunction with ancient DNA data and evidence from archaeological and historical records. A 247-bp mitochondrial D-loop sequence from 182 modern samples revealed a total of 70 haplotypes with a high level of genetic diversity. Seven major mtDNA haplogroups (A-G) and 16 clusters were identified for the 182 Chinese modern horses. In the present study, nine 247-bp mitochondrial D-loop sequences of ancient remains of Bronze Age horse from the Chifeng region of Inner Mongolia in China (c. 4000-2000a bp) were used to explore the origin and diversity of Chinese modern horses and the phylogenetic relationship between ancient and modern horses. The nine ancient horses carried seven haplotypes with rich genetic diversity, which were clustered together with modern individuals among haplogroups A, E and F. Modern domestic horse and ancient horse data support the multiple origins of domestic horses in China. This study supports the argument that multiple successful events of horse domestication, including separate introductions of wild mares into the domestic herds, may have occurred in antiquity, and that China cannot be excluded from these events. Indeed, the association of Far Eastern mtDNA types to haplogroup F was highly significant using Fisher's exact test of independence (P = 0.00002), lending support for Chinese domestication of this haplogroup. High diversity and all seven mtDNA haplogroups (A-G) with 16 clusters also suggest that further work is necessary to shed more light on horse domestication in China.