48 research outputs found
Video Capsule Retention in a Zenker Diverticulum
We report the case of a video capsule endoscope lodged within a Zenker diverticulum. The system that was equipped with a real-time viewer showed an unchanging image unlike esophageal or gastric mucosa, suggesting that the capsule was elsewhere. The presence of cervical discomfort suggested video capsule retention in a Zenker diverticulum. The capsule was removed endoscopically and reinserted using a hood-assisted endoscope and the procedure was completed
Narrowband lamellar multilayer grating with low contrast MoSi2 Si materials for soft X ray region
蓮華寺池と西湖 : 石野雲嶺の風景
The potential for increased drought frequency and severity linked to anthropogenic climate change in the semi-arid regions of the southwestern United States (US) is a serious concern1. Multi-year droughts during the instrumental period2 and decadal-length droughts of the past two millennia1, 3 were shorter and climatically different from the future permanent, ‘dust-bowl-like’ megadrought conditions, lasting decades to a century, that are predicted as a consequence of warming4. So far, it has been unclear whether or not such megadroughts occurred in the southwestern US, and, if so, with what regularity and intensity. Here we show that periods of aridity lasting centuries to millennia occurred in the southwestern US during mid-Pleistocene interglacials. Using molecular palaeotemperature proxies5 to reconstruct the mean annual temperature (MAT) in mid-Pleistocene lacustrine sediment from the Valles Caldera, New Mexico, we found that the driest conditions occurred during the warmest phases of interglacials, when the MAT was comparable to or higher than the modern MAT. A collapse of drought-tolerant C4 plant communities during these warm, dry intervals indicates a significant reduction in summer precipitation, possibly in response to a poleward migration of the subtropical dry zone. Three MAT cycles ~2 °C in amplitude occurred within Marine Isotope Stage (MIS) 11 and seem to correspond to the muted precessional cycles within this interglacial. In comparison with MIS 11, MIS 13 experienced higher precessional-cycle amplitudes, larger variations in MAT (4–6 °C) and a longer period of extended warmth, suggesting that local insolation variations were important to interglacial climatic variability in the southwestern US. Comparison of the early MIS 11 climate record with the Holocene record shows many similarities and implies that, in the absence of anthropogenic forcing, the region should be entering a cooler and wetter phase
Towards exploration of plant-based ethno-medicinal knowledge of rural community: basis for biodiversity conservation in Bangladesh
Effect of Rotational Speed on the Structural, Morphological, and Optical Properties of Biosynthesized Nickel Oxide Thin Films for Selective Solar Absorber Nanocoatings
This article presents a simple and low-cost green synthesized single-layer NiO selective solar absorber nanocoating prepared by spin coating on a Cu substrate at different rotational speeds (RS). The effects of substrate RS on the structural, morphological, chemical, and optical properties of the NiO nanocoatings were thoroughly investigated. The XRD results reveal the formation of pure diffraction peaks indexed to face-centered cubic NiO nanocoatings. SEM confirmed the uniform distribution of the NiO thin films with a nanosphere-like structure and the influence of RS variation on the formation of NiO nanostructures. EDS and XPS confirmed the presence of Ni and O in the green synthesized NiO coatings. AFM showed homogeneous nanopillar-like NiO thin films with the average surface roughness decreasing from 13.6 to 9.06 nm as the RS increased from 700 to 1300 RPM. Raman spectroscopy of the nanocoatings showed normal modes related to longitudinal optical and transverse optical phonons, and a combination of both, which implies the presence of a defect-rich or anti-ferromagnetically ordered NiO film responsible for the occurrence of more scattering peaks. UV–Vis–NIR and Fourier transform infrared spectroscopy (FTIR) were employed to characterize the optical properties of the nanocoatings. The green synthesized NiO nanocoatings deposited at 700 RPM exhibited excellent solar absorptance (α) of 0.92 and low thermal emittance (ɛ) of 0.11. The optical properties of the selective materials obtained in the present work were correlated with the non-stoichiometric nature of the spin-coated sample, multiple reflections, and interference-induced light absorption on the green synthesized surface. These results suggest that the NiO thin films prepared through this simple and environmentally benign green synthesis method can be promising candidates for efficient solar selective absorbers
Long-term Randomized Controlled Trial of a Novel Nanopowder Hemostatic Agent (TC-325) for Control of Severe Arterial Upper Gastrointestinal Bleeding in a Porcine Model
Background and study aim: Endoscopic therapy of brisk upper gastrointestinal bleeding remains challenging. A proprietary nanopowder (TC-325) has been proven to be effective in high pressure bleeding from external wounds. The efficacy and safety of TC-325 were assessed in a survival gastrointestinal bleeding animal model.
Method: 10 animals were randomized to treatment or sham. All animals received intravenous antibiotics, H2-blockers and heparin (activated clotting time 2 × normal). In a sterile laparotomy the gastroepiploic vessels were dissected, inserted through a 1-cm gastrotomy, and freely exposed in the gastric lumen, and the exposed vessel lacerated by needle knife. The treatment group received TC-325 by a modified delivery catheter while the sham group received no endoscopic treatment. Time to hemostasis, and mortality at 60 minutes, 24 hours, 48 hours, and 7 days were noted. Necropsy was performed in all animals.
Results: Spurting arterial bleeding was achieved in all animals. No control animal showed hemostasis within the first hour compared with 100 % (5 / 5) in the treatment arm (mean 13.8 minutes, P < 0.0079). Durable hemostasis was achieved with no evidence of rebleeding after 1 and 24 hours in 80 % (4 / 5) of the treated animals compared with none in the control group ( P < 0.0098). None of the control animals survived more than 6 hours. Necropsy at 1 week in treated animals revealed healed gastrotomy without foreign body granuloma or embolization to the lung or brain.
Conclusion: TC-325 is safe and highly effective in achieving hemostasis in an anticoagulated severe arterial gastrointestinal bleeding animal model
Uranium Retardation Capacity of Lithologies from the Negev Desert, Israel—Rock Characterization and Sorption Experiments
A series of batch experiments were performed to assess the uranium sorption capacity of four mineralogically distinct lithologies from the Negev Desert, Israel, to evaluate the suitability of a potential site for subsurface radioactive waste disposal. The rock specimens consisted of an organic-rich phosphorite, a bituminous marl, a chalk, and a sandstone. The sorption data for each lithology were fitted using a general composite surface complexation model (GC SCM) implemented in PHREEQC. Sorption data were also fitted by a non-mechanistic Langmuir sorption isotherm, which can be used as an alternative to the GC SCM to provide a more computationally efficient method for uranium sorption. This is because all the rocks tested have high pH/alkalinity/calcium buffering capacities that restrict groundwater chemistry variations, so that the use of a GC SCM is not advantageous. The mineralogy of the rocks points to several dominant sorption phases for uranyl (UO22+), including apatite, organic carbon, clays, and iron-bearing phases. The surface complexation parameters based on literature values for the minerals identified overestimate the uranium sorption capacities, so that for our application, an empirical approach that makes direct use of the experimental data to estimate mineral-specific sorption parameters appears to be more practical for predicting uranium sorption