Gastrointestinal neuroendocrine tumors(GI-NETs) are rare neoplasms, like all NETs. However, the incidence of GI-NETS has been increasing in recent years. Gastric NETs(G-NETs) and duodenal ...NETs(D-NETs) are the common types of upper GI-NETs based on tumor location. G-NETs are classified into three distinct subgroups: type?Ⅰ, Ⅱ, and Ⅲ. Type?Ⅰ?G-NETs, which are the most common subtype(70%-80% of all G-NETs), are associated with chronic atrophic gastritis, including autoimmune gastritis and Helicobacter pylori associated atrophic gastritis. Type Ⅱ G-NETs(5%-6%) are associated with multiple endocrine neoplasia type 1 and Zollinger-Ellison syndrome(MEN1-ZES). Both type?Ⅰ?and Ⅱ G-NETs are related to hypergastrinemia, are small in size, occur in multiple numbers, and are generally benign. In contrast, type Ⅲ G-NETs(10%-15%) are not associated with hypergastrinemia, are large-sized single tumors, and are usually malignant. Therefore, surgical resection and chemotherapy are generally necessary for type Ⅲ G-NETs, while endoscopic resection and followup, which are acceptable for the treatment of most type?Ⅰ?and Ⅱ G-NETs, are only acceptable for small and well differentiated type Ⅲ G-NETs. D-NETs include gastrinomas(50%-60%), somatostatin-producing tumors(15%), nonfunctional serotonin-containing tumors(20%), poorly differentiated neuroendocrine carcinomas(< 3%), and gangliocytic paragangliomas(< 2%). Most D-NETs are located in the first or second part of the duodenum, with 20% occurring in the periampullary region. Therapy for D-NETs is based on tumor size, location, histological grade, stage, and tumor type. While endoscopic resection may be considered for small nonfunctional D-NETs(G1) located in the higher papilla region, surgical resection is necessary for most other D-NETs. However, there is no consensus regarding the ideal treatment of D-NETs.
Background Use of endoscopic submucosal dissection (ESD) for management of widespread superficial esophageal carcinomas may be complicated by the development of severe strictures, which may require ...serial treatment with endoscopic balloon dilatation (EBD). Objective The goal of this study was to determine the efficacy of endoscopic triamcinolone injection (ETI) for the prevention of stricture formation after ESD. Design Case series. Setting Tertiary-care referral center. Patients A total of 41 consecutive patients who had a semi-circumferential mucosal defect that arose after ESD for superficial esophageal squamous cell carcinomas were enrolled in this study. Interventions EBD and ETI. Main outcome measurements Incidence of stricture and frequency of required EBD. Results ETI was performed in one group of patients (study group, n = 21) but not in the other (control group, n = 20). The incidence of stricture was significantly lower in the study group (19.0%) than in the control group (75.0%; P < .001). The number of required EBDs was also lower in the study group (mean, 1.7; range, 0-15) than in the control group (mean, 6.6; range 0-20). There were no side effects or complications associated with ETI. Limitations Nonrandomized study design and small number of patients in a single endoscopic center. Conclusions This study suggests that ETI is safe and effective for the prevention of esophageal stricture in patients undergoing ESD for superficial esophageal squamous cell carcinomas.
•18 Double-shear bond tests have been conducted to evaluate FRP EBR.•A critical review and assessment of existing bond stress–slip models was provided.•The factors affecting the bond stress–slip ...behavior were investigated and evaluated.•The newly proposed model is based on the bi-linear bond stress–strain relationship.•The new model is derived by considering only concrete compressive strength.
An important need in assessing the performance of externally bonded fiber reinforced polymer reinforcement (FRP EBR) for RC structures is to have a constitutive model for the bond stress–slip behavior. Various bond stress–slip models have been proposed and their effectiveness has been verified based on experimental and analytical data. Nevertheless, the models show significant variations and degrees of complexity. In this paper, bond interface modelling of EBR is explored and experimentally supported by double bond testing on 18 test specimens as part of an international Round Robin Testing (iRRT), to investigate the bond mechanisms between FRP reinforcement and concrete. Investigation of the database of models proposed by researchers in literature, shows that often reference is made to the so-called bilinear bond stress–slip model for externally bonded reinforcement. This model is based on three parameters: maximum bond stress, slip at maximum bond stress, and maximum slip. Applicable to this bilinear bond stress–slip model, simplified engineering equations are proposed to define the bond behavior, considering the effect of concrete strength and FRP stiffness on the three parameters identified. The simplified model has been verified against a database of experimental results, showing good correlation (with a coefficient of determination of more than 0.9). It is expected that the model will provide engineers with a basic design guideline to design safe EBR systems, and be a simple model for designing FRP strengthening applications.
Lithium-rich nickel–manganese–cobalt oxide, LiNi
0.17Li
0.2Co
0.07Mn
0.56O
2, was prepared by a co-precipitation method, and its cyclic behavior at a high potential was investigated. The as-prepared ...material shows a rapid capacity fading in its initial several cycles when it was operated above 4.5
V, which could be significantly improved through a pre-cycling treatment. Its reversible capacity in the range of 4.8–2
V could be increased from 200 to 250
mAh
g
−1 after 50 cycle through a stepped pre-cycling treatment.
The pathological significance of amyloid-β1–42 (Aβ1–42) dynamics is poorly understood in the brain extracellular compartment. Here we test which of the concentration or the retention is critical for ...Aβ1–42 toxicity after injection of equal dose into dentate granule cell layer of freely moving rats. The toxicity of Aβ1–42 (25 µM) was compared between injections at the rate of 0.25 µL/min for 4 min (fast injection) and 0.025 µL/min for 40 min (slow injection). Dentate gyrus long-term potentiation (LTP) was affected 1 and 2 h after the fast injection, but not 4 h. In contrast, LTP was affected even 72 h after the slow injection. Aβ1–42 staining 5 min after finish of the slow injection was more intense in the dentate granule cell layer than of the fast injection. The present study indicates that the retention of Aβ1–42 in the extracellular fluid is correlated with neuronal Aβ1–42 uptake and plays a key role in Aβ1–42 neurotoxicity. In the extracellular fluid of the dentate gyrus, the retention period of Aβ1–42 is much more critical for Aβ1–42 toxicity than Aβ1–42 concentration. It is likely that Aβ1–42 toxicity is accelerated by the disturbance of Aβ1–42 metabolism in the dentate gyrus.
Background
Even after successful
Helicobacter pylori
eradication, primary or metachronous gastric cancers are sometimes discovered. The endoscopic features of these cancers may be modified by ...controlling inflammation. Characteristic findings for such lesions in terms of narrow-band imaging with magnifying endoscopy (NBI-ME) and histopathology need to be clarified to allow accurate diagnosis.
Methods
Distinctive NBI-ME characteristics were examined retrospectively in intramucosal or minimally submucosal and differentiated-type adenocarcinomas from a successful eradication group (42 patients, 50 lesions) and a non-eradicated control group (44 patients, 50 lesions) matched in age and sex. A “gastritis-like” appearance under NBI-ME was characterized by uniform papillae and/or tubular pits with a whitish border, regular or faint microvessels and unclear demarcation, resembling the adjacent noncancerous mucosa. Histological differentiation at the luminal surface of the cancer was evaluated according to Ki-67 immunoreactivity restricted at the middle or lower portion of the tubules. NBI-ME alteration was prospectively confirmed in 29 patients (30 lesions) after eradication therapy.
Results
The frequency of a “gastritis-like” appearance was 44 % (22/50) for the eradication group, which was significantly higher than the 4 % (2/50) for the control group (
p
< 0.001). In the eradication group, the “gastritis-like” appearance was significantly correlated with histological surface differentiation (
p
< 0.001). In the prospective study, NBI-ME showed changes to heterogeneous papillary microstructures in 43 % (10/23) of the lesions after successful eradication at short-term follow-up.
Conclusions
Identification of surface maturation under NBI-ME offers a promising approach for accurate diagnosis of early gastric cancers after successful eradication.
▶ The structural changes of LiNi0.17Li0.2Co0.07Mn0.56O2 were studied using HAADF-STEM and SAED. ▶ Upon the first charge, some transition metal (TM) atoms were transferred from TM layers to Li layers. ...▶ A spinel structure was found from the early stage of the first charging process in the plateau region.
The structural changes upon the first charge and discharge of a Li-rich layered cathode material LiNi0.17Li0.2Co0.07Mn0.56O2 were investigated using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and selected-area electron diffraction (SAED). Atomic resolution STEM observations revealed that some of the transition metal (TM) atoms were transferred from the TM layers to the Li layers upon the first charge and discharge, leading to the partial formation of a framework structure. This framework structure was considered as a spinel structure based on our simulation results of the corresponding SAED pattern of the fully charged state. This framework structure was also recognized even at the early stage of the first charging process in the plateau region around 4.5V by using the SAED patterns, indicating that the formation of this framework structure started at the same time as the electrochemical activation.
•We model evaporative cooling from water surfaces in a micro-scale urban environment.•The predicted results are validated through comparison with experimental data.•The effect of evaporative cooling ...is qualitatively reproduced by a numerical model.•The maximum temperature decrease induced by the water surface was approximately 2°C.•The cooling effect is greatly affected by wind flow around buildings.
Computational fluid dynamics (CFD) simulations of the evaporative cooling effect from water surfaces in a micro-scale urban environment were evaluated via validation and application studies with various configurations. First, the basic ability of CFD simulations to reproduce the evaporative cooling on a simplified small-scale water surface in a boundary layer was investigated. Next, the prediction accuracy of the vapor transport mechanism from a water surface within an array of building was evaluated. It was confirmed that the vapor transport mechanism influenced by the complex wind flow around buildings could be reproduced by the current CFD code within a given accuracy. Finally, a numerical analysis that combined CFD and radiative heat transfer analysis was conducted for predicting the thermal environment around an actual residential neighborhood with a pond. The results were compared to experimental data. The experimental air temperature distribution around the pond was qualitatively reproduced via CFD. The maximum temperature decrease induced by the water surface was approximately 2°C at the pedestrian level. For a wind velocity of approximately 3m/s at a height of 10m, the effect of the evaporative cooling propagates downwind over an unobstructed distance of 100m.
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