Optical and molecular diversity of dissolved organic matter in sediments of the Daning and Shennong tributaries of the Three Gorges Reservoir

Introduction: Damming significantly modifies the function of natural river networks and influences sediment dynamics with a reservoir’s operation. The dissolved organic matter (DOM) in reservoir sediments severely affects carbon flow from land to sea. However, the properties of DOM (e.g., quantity and quality) in reservoir sediments and their relationship with carbon cycling remain unclear as complex reservoir construction interrupts the environmental processes.Methods: This study characterizes the optical and molecular properties of sediment water-extractable organic matter (WEOM) in the Daning and Shennong tributaries of the world’s largest reservoir—the Three Gorges Reservoir (TGR)—by applying optical techniques and ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS).Results and Discussion: We first assessed the link between light-absorbing components and the individual molecules in WEOM, which were significantly different than DOM in water and indicated that there might be an intrinsic variation between DOM in sediment and in water. Then, with the unique optical–molecular property linkage assessed, multiple sources (autochthonous and terrestrial) were identified, and a declining trend of terrestrial and recalcitrant WEOM was revealed from the tributaries upstream to downstream. Finally, through covariance analysis of the properties between WEOM and sediment particles, we demonstrated that the WEOM dynamic was most likely regulated by hydrologic sorting-induced particle size and mineral composition variations of sediment. Moreover, assessment between lability and WEOM molecular properties suggested that the WEOM dynamic likely contributes to carbon burial in the reservoir. This study emphasizes the influence of dam construction on organic matter accumulation and riverine carbon cycling

Identification and treatment of intestinal malrotation with midgut volvulus in childhood: a multicenter retrospective study

BackgroundIntestinal malrotation is a rare condition, and its delayed diagnosis can lead to fatal consequences. This study aimed to investigate the identification and treatment of malrotation in children.MethodsClinical data, imaging, operative findings, and early postoperative outcomes of 75 children with malrotation were retrospectively analyzed.ResultsThe mean age was 6.18 ± 4.93 days and 51.26 ± 70.13 months in the neonatal group (56 patients) and non-neonatal group (19 patients), respectively. Sixty-seven patients were under the age of 1 year at the time of diagnosis. The occurrence of bilious vomiting and jaundice was significantly higher in the neonatal group (89.29%) than that in the non-neonatal group (37.5%), p < 0.05 and p < 0.01, respectively. The incidence of abnormal ultrasound (US) findings was 97.30% and 100%, respectively, and the sensitivities of the upper gastrointestinal series were 84.21% and 87.5%, respectively. Sixty-six (88%) patients had midgut volvulus, including in utero volvulus (two patients) and irreversible intestinal ischemia (four patients). Most neonates (89.29%) underwent open Ladd's procedure with a shorter operative time (p < 0.01). Reoperation was performed for postoperative complications (four patients) or missed comorbidities (two patients).ConclusionsNon-bilious vomiting was the initial symptom in >10% of neonates and nearly 40% of non-neonates. This highlights the importance for emergency physicians and surgeons to be cautious about ruling out malrotation in patients with non-bilious vomiting. Utilizing US can obviate the need for contrast examinations owing to its higher diagnostic accuracy and rapid diagnosis and can be recommended as a first-line imaging technique. Additionally, open surgery is still an option for neonatal patients

The Credit Risk Contagion Mechanism of Financial Guarantee Network: An Application of the SEIR-Epidemic Model

Financing guarantee is an important means and key link to solve the financing difficulties of small- and medium-size enterprises (SMEs). However, while financial guarantees alleviate the financing difficulties of SMEs, the complex guarantee relationships also constitute a new channel for credit risk contagion in the financial guarantee network. In this paper, we construct a model of credit risk contagion process of guarantee network based on SEIR and analyse the equilibrium point and stability of the model. Then, we find the threshold value of risk contagion and further simulate the SEIR model dynamically to analyse the influence of each parameter of the model. The results show that the risk of the financing guarantee network begins to be widely contagious only when risk contagion threshold is greater than 1, and the conversion rate of exposed enterprises, removal rate of infected enterprises, nodal enterprises degree, and risk contagion rate have significant effects on the changes of individual density of susceptible, exposed, infected, and recovered enterprises. Combining the above findings, it is of great theoretical and practical significance to propose relevant countermeasures for credit risk control of financial guarantee network

Symbiotic Mechanism of Multiple Subjects for the Resource-Based Disposal of Medical Waste in China in the Post-Pandemic Context

In the post-pandemic era, the continuous growth in the rate of medical waste generation and the limited capacity of traditional disposal methods have posed a double challenge to society and the environment. Resource-based disposal is considered an efficient approach for solving these problems. Previous studies focused on the methods of medical waste disposal and the behavior of single stakeholders, lacking consideration of cooperation among different stakeholders. This study establishes an evolutionary game model of the resource-based disposal of medical waste to analyze the behavioral decision evolution of governments, medical institutions, and disposal enterprises. This study also explores the influencing factors in the achievement of the symbiotic state and investigates the conditions that participants need to meet. The results show that joint tripartite cooperation can be achieved when the subsidies and penalties from governments are sufficient, as well as the efficiency of resource-based disposal, which can effectively promote the evolution of the three subjects from the state of “partial symbiosis” to the state of “symbiosis”. However, the resource-based classification level cannot directly change the symbiotic state of the system due to the goal of minimizing cost and risk. When evolutionary subjects have reached the state of “symbiosis”, the improvement in the classification level can enhance the willingness of disposal enterprises to choose the resource-based classification strategy. Under such circumstances, governments reduce their corresponding level of intervention. At this time, the whole system is in a more idealized symbiotic state

Evolutionary Game Analysis of Medical Waste Disposal in China under Different Reward and Penalty Models

Although local governments have issued relevant reward and penalty policies, there are still problems of medical waste disposal in China, particularly in light of the special situation of the COVID-19 pandemic. Furthermore, these problems are generated in the game between local governments and disposal enterprises. Accordingly, based on the evolutionary game theory, this paper establishes and analyzes the game system between local governments and disposal enterprises under four modes: static reward and static penalty, dynamic reward and static penalty, static reward and dynamic penalty, and dynamic reward and dynamic penalty. The theoretical analysis is verified through numerical simulation of a medical waste disposal case in China. The results showed that when local governments choose the static reward and static penalty mode, the game system hardly always has an evolutionary stable state, and the dynamic reward or dynamic penalty mode can make up for the shortcomings of the static reward and static penalty mode. The static reward and dynamic penalty mode is considerably better than the other two dynamic reward and penalty modes, which has the best effect on improving the quality of medical waste disposal. Additionally, if the reward or penalty increases dynamically, local governments tend to implement a “relaxed supervision” strategy, and disposal enterprises will still improve the disposal quality of medical waste. The suggestions proposed based on the research conclusions offer some enlightenment for policymakers to formulate reasonable reward and penalty measures

The Design of Incentive Mechanism for Policy-Oriented Guarantee Institutions’ Digital Transformation in China

Currently, China is actively promoting the reform process of the digital economy, and the digital transformation of the credit financing guarantee sector is gradually emerging. As the core driving force for the progress of digital transformation, the optimal design of the incentive mechanism is undoubtedly essential. Based on the principal-agent relationship between local governments and policy-oriented guarantee institutions, this study constructs a basic incentive model (model I) and an incentive model introducing a regulatory signal (model II), empirically analyzes the digital transformation effort of guarantee institutions under the influence of different factors and discusses how local governments should design the optimal incentive mechanism. The results show that the digital transformation effort level of guarantee institutions in model II is higher than that in model I, while the incentive intensity of local governments in model II is lower than that in model I. Within the range of guarantee compensation rate less than a specific threshold, the risk perception degree has negative effects on the effort level and incentive intensity of DT. In addition, the regulatory intensity has a constant negative effect on the incentive intensity of the DT, while it has a negative effect on the effort level of the DT only if the guarantee capacity is below a specific threshold. The research results can provide practical guidance for local governments to effectively promote digital transformation activities and improve the competitiveness of credit financing guarantee

MONITORING DYNAMIC DEFORMATION OF SHUTTLE STEEL SHELVES BY DIGITAL PHOTOGRAPHY

Shuttle steel shelves (steel shelves equipped with shuttles) are popular in modern logistics. The safety of shuttle steel shelves is an issue due to the complicated dynamic load that develops when the shuttles are in operation. As deformation is an important index of structural safety, this study uses a DPS (digital photography system) based on the PST-IM-MP (photograph scale transformation-image matching-motion parallax) method to monitor shuttle steel shelves: a digital camera (SONY350) was used to monitor the dynamic deformation of shuttle steel shelves when the shuttles began to move, accelerated, moved at constant speed, decelerated and stopped. Then, the deformation trends of the shuttle steel shelves were depicted to study the moving trajectory in a local area. Moreover, we analysed the stresses in the shuttle steel shelves based on these monitoring data. The results showed that the PST-IM-MP method can meet the accuracy requirements in monitoring the dynamic deformation of steel shelves as the maximum and minimum measurement errors were 0.74 pixels and 0.34 pixels in the comprehensive direction, respectively. The shuttle steel shelves were robust because the deformations were elastic and within the allowed10mm. Shear and tension stresses developed in the shuttle steel shelves when the shuttles were in operation. Thus, in the future DPS will become popular for monitoring shuttle steel shelves in real time to warn of possible dangers and mitigate hazards. Additionally, the monitoring data can be used to study the stability of the shuttle steel shelves to improve the related stability design theory

The Clinical Manifestation Variety and Management Choice of Meckel’s Diverticulum with Complication: A Single Center Experience

Background. The study was to analyze the clinical manifestation variety and management choices of symptomatic Meckel’s diverticulum in children. Methods. From July 2008 to October 2018, 28 cases of Meckel’s diverticulum with a variety of complications were admitted to our hospital. The clinical data included age, gender, symptoms and signs, investigations, intraoperative and pathological findings, and outcome. Results. The ratio of males to females was 2.5 : 1. The diagnoses were made by 99mTc-pertechnetate scan (in 5 cases) and by exploratory laparotomy (in 2 cases). The initial diagnosis in the other cases includes intussusception (in 4 cases), acute appendicitis (in 5 cases), intestinal obstruction (unknown origin), peritonitis, and even shock in 12 cases. Laparoscopic surgery was performed in 8 cases; 18 cases underwent open surgery. Excision of partial bowel segment with diverticulum and primary anastomosis was done in 22 cases and wedge resection of diverticulum in 4 cases. Two other cases received nonoperative therapy and went to other hospitals to receive surgical management. Ectopic gastric mucosa in the diverticulum was found in 9 cases, including 6 cases with lower gastrointestinal bleeding. Conclusion. The clinical characteristics of Meckel’s diverticulum varied. Children with hematochezia, peritonitis, and intestinal obstruction without history of prior abdominal operation should be suspected with this disease until proven otherwise. Hematochezia is often associated with ectopic gastric mucosa in the diverticulum. Laparoscopic surgery should be one of the choices for the diagnosis and treatment of Meckel’s diverticulum with complications

Influence of Solvent and Electrical Voltage on Cathode Plasma Electrolytic Deposition of Al2O3 Antioxidation Coatings on Ti-45Al-8.5Nb Alloys

Al2O3 coatings were prepared on Ti-45Al-8.5Nb alloys via cathodic plasma electrolysis deposition (CPED) in both 1.2 M Al(NO3)3 aqueous and ethanolic solutions. Different voltages were also applied during the deposition process to optimize coating properties. Coatings deposited in both solutions mainly consisted of γ-Al2O3, with some Al(OH)3 found in coatings prepared in aqueous solution. Coatings prepared in ethanol solution exhibited better oxidation resistance at 900 °C as well as better substrate adhesion, which was mainly due to smaller crater sizes on coating surfaces. The deposition process was discussed in detail and the reason for the smaller craters examined. The results suggested that solution surface tension mainly influenced the average diameter of hydrogen bubbles that formed on cathode surfaces during the process. Smaller bubbles lead to both lower current densities on cathodes and smaller crater sizes on coatings

An Alternative Technique for Transumbilical Single-Port Laparoscopic Percutaneous Precise Closure of the Inguinal Hernia Sac in Children: A 3-Year Single-Centre Study

Objective. To evaluate the safety and reliability of a novel technique of single-port laparoscopic-assisted percutaneous precise closure of the inguinal hernia sac in children. Methods. From September 2016 through September 2019, children with inguinal hernia(s) treated with single-port laparoscopic-assisted percutaneous extraperitoneal closure using a guide wire were enrolled in this study. Operative time, surgical complications, recurrence rate, and cosmetic results were collected. Results. A total of 917 cases with inguinal hernia(s) were collected. Among them, there were 886 (96.61%) boys and 31 girls. Their mean age was 5.2±3.7 years. There were 693 (75.57%) cases with unilateral hernia. There were 224 cases with bilateral hernias or patent processus vaginalis, including 135 (14.72%) cases with an open contralateral ring which was confirmed intraoperatively. Twenty-three (2.51%) needed another port to complete the hernia sac separation. The operation time was 24.7±5.2 min and 14.6±3.8 min in bilateral and unilateral ones. Three cases complained of numbness in the thigh region or groin pain which subsided without medication in the 2nd postoperative month. There was no recurrence, and the incision scars were nearly invisible. Conclusion. Single-port laparoscopic-assisted percutaneous extraperitoneal closure using a guide wire is a safe, less cost, and reliable technique in the treatment of inguinal hernia in children