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Internal multiples bring great challenges for conventional seismic data imaging and interpretation, in which primaries only are regarded as signals. It is of great importance to suppress the internal multiples before conventional imaging, which is computationally expensive. Considering that internal multiples are also real reflections from the underground interfaces and reverse time migration (RTM) can realize the imaging of multiples. Instead of suppression before imaging, we propose to do the joint imaging of primaries and internal multiples based on RTM. However, the artifacts caused by the internal multiples should be suppressed to guarantee the precision. First, the imaging condition based on up-going and down-going extrapolated wavefield separation is introduced to improve the imaging accuracy. Then, the generation mechanism of image artifacts is analyzed, and it concludes that nonphysical wave paths caused by the missing boundary wavefields under the surface result in the infidelity reversed-time backward-extrapolation, which is the main reason for the artifacts. Next, we propose to apply the modeling boundary wavefields with a match based on pseudomultichannel matching filter to compensate the missing boundary wavefields, which can avoid the image artifacts and realize high-precision joint imaging. Finally, the feasibility and effectiveness of the proposed method are verified by numerical examples and field data. [ABSTRACT FROM AUTHOR]

Artificially polluted surface water was treated using magnetic-seeding coagulation, with polyaluminum chloride (PAC) as the coagulant and a ferromagnetic material as the magnetic seed (MS). A novel approach using a combination of response surface methodology (RSM) and the Box–Behnken design (BBD) was employed to evaluate the effects and interactions of four main factors, the dosages and dosing points of PAC and MS. The three response variables selected to evaluate the effectiveness of the treatment were supernatant turbidity removal rate, floc size, and floc strength. The optimal operating conditions were obtained by constraining the three desirable responses using Minitab software. The PAC and MS dosages (22.7 mg/L and 0.6 g/L) and their dosing points (1.5 and 1.2 min) were determined to be the optimum conditions for the maximum turbidity removal rate, floc size, and floc strength of 98.0%, 154.7 μm, and 57.8%, respectively. Confirmation experiments demonstrated that such a combination of RSM and BBD was a powerful and effective approach for optimizing the magnetic-seeding coagulation. Additionally, zeta potential analysis indicated that the MS decreases the negative charge of pollutants and acts as a coagulating core during coagulation. [ABSTRACT FROM AUTHOR]

Background: Acute pancreatitis (AP) is a serious and can be lethal disease, with an incidence of 13 to 45 per 100,000 individuals per year. The underlying mechanism of AP is not fully understood. Exosomes have recently been identified as intercellular messengers that can participate in the pathogenesis of various diseases. Exosomes secreted by noninflammatory acinar cells may affect the activated and injured acinar cells during AP., Aim: To investigate the effect of exosomes derived from acinar cells on the pathogenesis of AP., Methods: Nanoparticle tracking analysis was applied to evaluating the exosomes derived from AR42J acinar cells. The viability and apoptosis of AP in vitro model cells were evaluated. Wistar rats were used to establish the in vivo AP rat model and the levels of serum pro-inflammatory cytokines and morphological changes in the pancreatic tissues were assessed. RNA sequencing and Kyoto Encyclopedia of Genes and Genomes databases (KEGG) based RNA enrichment analyses were applied to exploring the mechanisms underlying the effect of exosomes on the pathogenesis of AP., Results: Acinar cell exosomes reduced the level of intracellular ROS production and improved the viability of AP model acinar cells by inhibiting apoptosis during AP. The exosomes decreased the circulating levels of IL-6 and TNF-alpha, and reduced the pathological scores and wet/dry weight ratios of pancreatic tissue in AP in vivo model rats. Among the upregulated and downregulated RNAs analyzed, the MAPK and NF-kappaB signaling pathways might be involved in the mechanisms underlying the protective effects of acinar cell-derived exosomes in AP., Conclusion: Acinar cell-derived exosomes could reduce the apoptosis and ROS production in acinar cells during AP, and may alleviate the severity of AP via the MAPK and NF-kappaB signaling pathways.

Objective: To investigate the clinical feature, diagnostic and therapeutic experience of autoimmune pancreatitis (AIP)., Methods: Twenty-one patients with AIP treated in the First Affiliated Hospital, Harbin Medical University from January 2006 to July 2014 were analyzed retrospectively. There were 15 men and 6 women among the 21 cases and the age ranged from 36 to 64 years. The characters of diagnosis and treatment of AIP were explored through clinical symptoms, imaging features, serologic test results, diagnostic treatment, and histopathologic characteristics., Results: All the patients showed obstructive jaundice and upper abdominal pain to different extents as major manifestations and the levels of serum IgG4, CA19-9, CEA were elevated in 16 cases (76.2%), 6 cases (28.5%) and 3 cases (14.2%), respectively. CT showed diffuse enlargement of the pancreas in 9 cases, localized pancreatic head enlargement in 3 cases and focally pancreatic mass in 9 cases. AIP was confirmed by extrapancreatic involvement, radiological and serological results plus biopsy in 11 cases (52.4%), interpretation of response to steroid in 3 cases (14.3%) and open laparotomy in 7 cases (33.3%). Surgery included choledochojejunostomy in 3 cases, cholecystojejunostomy in 1 case, pancreaticoduodenectomy in 2 cases and distal pancreatectomy combined with splenectomy in 1 case. The pathologic results displayed massive lymphocytes and plasma cells infiltration in the pancreatic tissues as well as parenchymal fibrosis. Except for 1 patient who had no symptom, the regular steroid therapy was performed (oral prednisone) and all the patients were cured. The follow-up time range was from 3 to 93 months, 4 cases (19.0%) were recurrent followed by the symptoms alleviated after the steroid was applied again., Conclusions: AIP is rare and characterized by non-specific clinical manifestations so that the early diagnosis is difficult with a high misdiagnosis rate. The clinicians should strengthen the recognition of AIP and the definite diagnosis depends on the combination of clinical manifestations, radiological, serological and histopathological results so as to avoid the unnecessary operation.