64 research outputs found
Natural Orifice Translumenal Endoscopic Surgery for Anterior Spinal Procedures
Background. NOTES techniques allow transesophageal access to the mediastinum. The aim of this study was to assess the feasibility of transesophageal biopsy of thoracic vertebrae. Methods. Nonsurvival experiments on four 50-kg porcine animals were performed. Transesophageal access to the mediastinum was attained using submucosal tunneling technique. Results. The posterior mediastinum was successfully accessed and navigated in all animals. Vertebral bodies and intervertebral spaces were easily approached while avoiding damage to adjacent vessels. Bone biopsy was successfully performed without complications, but the hardness of bone tissue resulted in small and fragmented samples. Conclusions. Peroral transesophageal access into the posterior mediastinum and thoracic vertebral bone biopsy was feasible and safe. The proximity of the esophagus to the vertebral column provides close and direct access to the thoracic spine and opens up new ground for the performance of multilevel anterior spine procedures using NOTES techniques
Se Isotopes as Groundwater Redox Indicators:Detecting Natural Attenuation of Se at an in Situ Recovery U Mine
One
of the major ecological concerns associated with the in situ
recovery (ISR) of uranium (U) is the environmental release of soluble,
toxic selenium (Se) oxyanions generated by mining. Post-mining natural
attenuation by the residual reductants in the ore body and reduced
down-gradient sediments should mitigate the risk of Se contamination
in groundwater. In this work, we investigate the Se concentrations
and Se isotope systematics of groundwater and of U ore bearing sediments
from an ISR site at Rosita, TX, USA. Our results show that selenate
(Se(VI)) is the dominant Se species in Rosita groundwater, and while
several up-gradient wells have elevated Se(VI), the majority of the
ore zone and down-gradient wells have little or no Se oxyanions. In
addition, the δ<sup>82</sup>Se<sub>VI</sub> of Rosita groundwater
is generally elevated relative to the U ore up to +6.14‰, with
the most enriched values observed in the ore-zone wells. Increasing
δ<sup>82</sup>Se with decreasing Se(VI) conforms to a Rayleigh
type distillation model with an ε of −2.25‰ ±
0.61‰, suggesting natural Se(VI) reduction occurring along
the hydraulic gradient at the Rosita ISR site. Furthermore, our results
show that Se isotopes are excellent sensors for detecting and monitoring
post-mining natural attenuation of Se oxyanions at ISR sites
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
An ethnobotanical study of medicinal plants used by local people in the lowlands of Konta Special Woreda, southern nations, nationalities and peoples regional state, Ethiopia
<p>Abstract</p> <p>Background</p> <p>Research was carried out in Konta Special Woreda (District); it is a remote area with lack of infrastructure like road to make any research activities in the area. Therefore, this research was conducted to investigate medicinal plants of the Konta people and to document the local knowledge before environmental and cultural changes deplete the resources.</p> <p>Methods</p> <p>The information was collected between October 2006 and February 2007. Interview-based field study constituted the main data collection method in which the gathering, preparation, use, previous and current status and cultivation practices were systematically investigated. The abundance, taxonomic diversity and distribution of medicinal plants were studied using ecological approach.</p> <p>Results</p> <p>A total of 120 species, grouped within 100 genera and 47 families that are used in traditional medical practices were identified and studied. The Fabaceae and Lamiaceae were the most commonly reported medicinal plants with 16 (13.3%) and 14 (12%) species, respectively. 25.4% of the total medicinal plants are collected from homegardens and the rest (74.6%) are collected from wild habitats. Of the total number of medicinal plants, 108 species (90%) were used to treat human ailments, 6 (5%) for livestock diseases and the remaining 6 (5%) were used to treat both human and livestock health problems. The major threats to medicinal plants reported include harvesting medicinal plants for firewood (24.8%) followed by fire (22.3%) and construction (19%). Of the four plant communities identified in the wild, more medicinal plant species (34) were found in community type-4 (<it>Hyparrhenia cymbaria</it>-<it>Erythrina abyssinica </it>community), which accounted for 61.8%.</p> <p>Conclusion</p> <p>Konta Special Woreda is an important area for medicinal plants and associated local knowledge; the natural vegetation being the most important reservoir for the majority of the medicinal plants. Environmental and cultural changes are in the process of threatening the resources and this signals the need for serious efforts to create public awareness so that measures are taken to conserve the medicinal plants in the natural ecosystems and other suitable environments.</p
Towards exploration of plant-based ethno-medicinal knowledge of rural community: basis for biodiversity conservation in Bangladesh
Daytime twin-peak structures observed at southern African and European middle latitudes on 8–13 April 2012
Daytime twin-peak structures, also known as bite-out or diurnal double-maxima
structures, are ionospheric phenomena in which the diurnal ionospheric trend
shows two peaks (instead of the normal one) during the daytime. This study
reports on first simultaneous observations of these structures in the Global
Positioning System and ionosonde measurements from the southern African and
European middle-latitude stations during a mostly quiet geomagnetic condition
period of 8–13 April 2012, which indicates that their occurrence and
therefore driving mechanism(s) may not be localised. It is found that the
daytime twin-peak structures generally appear later in the Northern
Hemisphere with a 1–3 h latency although they propagate mostly equatorward
in both hemispheres. Proxies of meridional neutral winds were calculated from
available manually scaled ionosonde measurements and used to explore their
potential as drivers of the structures. Bite-out events were linked to
downward drifts of the vertical component of equivalent neutral winds causing
plasma depletions. In addition, evidence of sporadic E layers at the same time
as enhancements of daytime twin-peak structures suggests that the tides had
influence via the meridional wind shear in generating these structures
through the dynamo electric field which resulted in upward
<b>E</b> × <b>B</b> drifts
Computational fluid dynamics modelling of the microclimate within the boundary layer of leaves leading to improved pest control management and low-input greenhouse
This work aims at using the Computational Fluid Dynamic (CFD) approach to study the distributed microclimate in the leaf boundary layer of greenhouse crops. Understanding the interactions in this microclimate of this natural habitat of plant pests (i.e., boundary layer of leaves), is a prerequisite for their control through targeted climate management for sustainable greenhouse production. The temperature and humidity simulations, inside the greenhouse, were performed using CFD code which has been adapted to simulate the plant activity within each mesh in the crop canopy. The air temperature and air humidity profiles within the boundary layer of leaves were deduced from the local surrounding climate parameters, based on an analytical approach, encapsulated in a Used Defined Function (UDF), and dynamically linked to the CFD solver, a work that forms an innovative and original task. Thus, this model represents a new approach to investigate the microclimate in the boundary layer of leaves under greenhouses, which resolves the issue of the inaccessibility of this area by the conventionnel measurement tools. The findings clearly showed that (i) contrarily to what might be expected, the microclimate parameters within the boundary layer of leaves are different from the surrounding climate in the greenhouse. This is particularly visible during photoperiods when the plant’s transpiration activity is at its maximum and that (ii) the climatic parameters in the leaf boundary layer are more coupled with leaf surfaces than with those of greenhouse air. These results can help developing localized intervention strategies on the microclimate within boundary layer of plant leaves, leading to improved and sustainable pest control management. The developed climatic strategies will make it possible to optimize resources use efficiency. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Computational fluid dynamics modelling of the microclimate within the boundary layer of leaves leading to improved pest control management and low-input greenhouse
This work aims at using the Computational Fluid Dynamic (CFD) approach to study the distributed microclimate in the leaf boundary layer of greenhouse crops. Understanding the interactions in this microclimate of this natural habitat of plant pests (i.e., boundary layer of leaves), is a prerequisite for their control through targeted climate management for sustainable greenhouse production. The temperature and humidity simulations, inside the greenhouse, were performed using CFD code which has been adapted to simulate the plant activity within each mesh in the crop canopy. The air temperature and air humidity profiles within the boundary layer of leaves were deduced from the local surrounding climate parameters, based on an analytical approach, encapsulated in a Used Defined Function (UDF), and dynamically linked to the CFD solver, a work that forms an innovative and original task. Thus, this model represents a new approach to investigate the microclimate in the boundary layer of leaves under greenhouses, which resolves the issue of the inaccessibility of this area by the conventionnel measurement tools. The findings clearly showed that (i) contrarily to what might be expected, the microclimate parameters within the boundary layer of leaves are different from the surrounding climate in the greenhouse. This is particularly visible during photoperiods when the plant’s transpiration activity is at its maximum and that (ii) the climatic parameters in the leaf boundary layer are more coupled with leaf surfaces than with those of greenhouse air. These results can help developing localized intervention strategies on the microclimate within boundary layer of plant leaves, leading to improved and sustainable pest control management. The developed climatic strategies will make it possible to optimize resources use efficiency. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
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