Mixed-ownership reform and factor misallocation: Evidence from China.

An enterprise's ownership structure is crucial for factor allocation efficiency. We used Chinese firm-level data to investigate whether changes in state-owned enterprise ownership structure contribute to resource misallocation, leading to high-quality economic development. We found a U-shaped relationship between non-state shareholding and state-owned enterprises' resource allocation efficiency. An optimal range exists for non-state shareholding. When the shareholding of non-state shareholders reaches 10%-20%, the efficiency of resource allocation is at its highest. Additional research has revealed that mixed shareholding has varying impacts on resource allocation, displaying substantial heterogeneity. These insights offer valuable guidance for future mixed-ownership reforms and serve as a practical reference for economic reforms in other nations, particularly developing countries.

Assessment of the necessity of uterine artery embolization during suction and curettage for caesarean scar pregnancy: a prospective cohort study.

BACKGROUND: Uterine artery embolization (UAE) followed by suction and curettage is a common conservative treatment for caesarean scar pregnancy (CSP), but the advantages of suction and curettage alone are underestimated due to the lack of standards for selecting appropriate cases for which this approach would be applicable. We sought to identify indicators with which to assess the need for UAE during suction and curettage. METHODS: The prospective cohort consisted of 105 women diagnosed with CSP in Peking Union Medical College Hospital between January 2016 and September 2018 who were followed up until 60 days after surgery. The main outcome was the therapy used, and secondary outcomes included recovery, bleeding, surgery time, length of hospital stay, and total cost. RESULTS: We found that ß-human chorionic gonadotropin (ß-hCG) levels were significantly lower (P < 0.05), foetal cardiac activity was significantly lower (P < 0.05), the myometrial layer was significantly thicker (P < 0.05), expenditures were lower and lengths of hospital stay were shorter in patients who received suction and curettage alone (the non-UAE group) than in those who received UAE followed by suction and curettage (the UAE+ group). In addition, for CSP patients, UAE might be less necessary when the myometrial thickness is ≥2 mm and the gestational sacmeasures ≤5 cm, and suction and curettage alone may be safer for these patients. CONCLUSION: Suction and curettage alone is a more suitable option than UAE followed by suction and curettage because the former carries a lower cost, shorter length of hospital stay, and lower risk of adverse events. Regarding risk factors, patients with a lower uterine segment thickness ≥ 2 mm and a gestational mass diameter ≤ 5 cm have an increased probability of being successfully treated with suction and curettage alone.

[Distribution Characteristics and Ecological Risk Assessment of Organochlorine Pesticides in Sediments of Zhanjiang Bay].

Sixteen surface sediment samples were collected from the estuary of the Suixi river to the mouth of Zhanjiang Bay and then analyzed for organochlorine pesticides (OCPs) by GC-MS to investigate their distribution and ecological risk. The results showed that the concentrations of OCPs in the sediments ranged from nd to 189.52 ng·g-1 (mean 32.17 ng·g-1), including HCHs (mean 5.81 ng·g-1) and DDTs (mean 26.90 ng·g-1). The distribution characteristics showed that the highest OCPs concentrations were found in the estuary and the main shipping lane areas, and the concentration in the nearshore area was higher than that offshore. Source analysis indicated that the HCHs mainly originated from agricultural applications, while no industrial input was observed. Some "hot-spots" areas occurred in harbors and shipping channels, likely as a result of the presence of paint flakes. Additionally, the concentrations of DDTs were found to be higher than the limits of Chinese Marine sediment quality criteria, and p,p'-DDT was the main type of DDT, presenting inevitable adverse biological effects and high ecological risk. Compared with other bays in China, the concentrations of OCPs in this study were in the upper-median pollution level, especially in harbors and boat maintenance facility areas. High OCPs inputs may occur, and thereby represent a certain ecological risk in Zhanjiang Bay.

Computerized tomography angiography in preoperative assessment of intravenous leiomyomatosis extending to inferior vena cava and heart.

BACKGROUND: Intravenous leiomyomatosis (IVL) extending to inferior vena cava and heart is one of the most challenging conditions for surgical treatment. We explored the use of computerized tomography angiography (CTA) in preoperative assessment for this disease. METHODS: A cohort of 31 patients with IVL extending to inferior vena cava and heart were reviewed from the year 2002 to 2014, focusing on the preoperative CTA imaging characteristics and the surgical procedures in clinical treatment. RESULTS: All patients were diagnosed correctly combining the clinical medical history and CTA imaging. Thirteen patients had tumors confined within the inferior vena cava, and 18 patients had tumors intruding into the right heart. Furthermore, 15 tumors were located in the right atrium alone, and 3 tumors involved both the right atrium and the right ventricle. All patients had simple or multiple soft tissue masses from the pelvis, with 22 tumors extending into inferior vena cava through the iliac veins and 9 tumors through the ovarian veins. Three patients had tumors invading into lung and underwent tumor thrombus resection in the pulmonary artery. Patients received either one-stage surgery or two-stage surgery dependent on patient general condition and tumor status. All operations were successfully performed by multidisciplinary cooperation, including gynecology, cardiac surgery, and vascular surgery, without severe surgical-related complications or deaths. CONCLUSIONS: CTA imaging can present location, size, and full-scale extension pathway of IVL lesions, and can be used as first-line imaging technique in preoperative assessment, having great significance in making surgical plan and obtaining successful outcome.

Occurrence and carcinogenic potential of airborne polycyclic aromatic hydrocarbons in some large-scale enclosed/semi-enclosed vehicle parking areas.

Polycyclic aromatic hydrocarbons (PAHs) originating from vehicle exhaust have aroused much attention due to their potential healthy effect. In this study, air samples were collected from three representative parking lots in a metropolitan area, analyzed for PAHs and evaluated for inhalation risk. Atmospheric PAH levels of these parking areas ranged between 1,178-4,793 ng m(-3), one order of magnitude higher than general urban areas. Their benzo[a]pyrene equivalent (BaPeq) values varied in 11.0-98.0 ng m(-3), far exceeding the air quality standard of WHO (1.0 ng m(-3)). Monte Carlo simulation (100,000 trials) results suggest that the potential lifetime inhalation cancer risks of PAHs were 0.27 × 10(-5) to 7.11 × 10(-5) for park employees, which are in the acceptable range acknowledged by US EPA (1.0 × 10(-6) to 1.0 × 10(-4)). Several source diagnostic methods proved that vehicle exhaust was the dominant PAH contributor of these parks with the contribution percentages being >53%; oil combustion and/or coal combustion were other important sources. Logarithms of gas-particle distribution coefficients (Kps) of PAHs in all studied parks were linearly correlated with those of both their sub-cooled vapor pressures (pLs) and octanol-air partition coefficients (KOAs). The correlation coefficients indicated that both adsorption onto black carbon and absorption into organic matter were involved in the partition process, but the latter was dominant.

Spatial distribution of polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDDs/Fs) in dust, soil, sediment and health risk assessment from an intensive electronic waste recycling site in Southern China.

Workshop dust, soil and sediment samples were collected to investigate the level and spatial distribution of PCDDs/Fs at an intensive electronic waste (e-waste) recycling site in Southern China, and also to characterize the dioxin emission in different e-waste recycling procedures. The concentrations of total PCDDs/Fs ranged from 1866 to 234292 ng kg(-1) for the dust samples, from 3187 to 63998 ng kg(-1) dry wt for the top soils, and 33718 ng kg(-1) for the surface sediment. All the samples were characterized by abnormally high concentrations of OCDD and an extremely low portion of PCDFs. Different e-waste recycling procedures may generate different congener profiles. Open burning and dismantling were the two procedures emitting relatively higher concentrations of PCDDs/Fs in this case, indicating that low-tech recycling operations were one of the major contributors of PCDDs/Fs to the environment. The variation and distinction of the concentrations and homologue/congener profiles among different environmental matrices reveal the characteristics of contaminant environmental behavior and fate during the transportation from "source" to "sink". Daily intake of PCDDs/Fs through soil ingestion and dermal absorption was negligible, but the rough estimated total PCDD/F intake dose far exceeded the tolerance daily intake value of 4 pg-TEQ per kg per day recommended by WHO, indicating that residents in Longtang were at a high risk of exposure to dioxins, especially children.