2,622 research outputs found
Management of congenital esophageal stenosis associated with esophageal atresia and its impact on postoperative esophageal stricture
Aim The aim of this work was to study the incidence, management of congenital esophageal stenosis (CES) associated with esophageal atresia (EA) and tracheoesophageal fistula (TEF), and its impact on esophageal stricture (ES) after primary repair.Patients and methods From January 2006 to December 2014, 41 sequential cases of EA with distal TEF were retrospectively studied. Cases with significant ES after primary repair were included in the study. Associated CES was diagnosed in the neonatal period by taking histopathologic samples from the tips of the esophageal pouches, failure to pass a size-6 nasogastric tube distally during primary repair, and by initial esophagogram.Results Significant ES developed in 19 patients (46.3%); of them, six had CES (32%). Three patients had tracheobronchial remnants at the anastomotic site. Two of them had refractory strictures requiring resections and one had mainly major esophageal dysmotility. Patients 4 and 5 had CES distal to the anastomotic site on initial esophagogram. Patient 4 responded well to dilatations, whereas the other one had refractory stricture. Patient 6 had distal CES due to fibromuscular stenosis diagnosed by failure to pass a size-6 nasogastric tube distally. The patient responded well to dilatation, myectomy, and Thal’s fundoplication.Conclusion One-third of the patients with significant stricture had CES; half of them were refractory to dilatation. Failure to have histology specimens and a high index of suspicion will make the incidence of this association a rarity. Diagnosis and management of CES with EA/TEF in the neonatal period is possible. Esophageal dilatation is the initial management for all cases with a low threshold for gastric fundoplication and gastrostomy. Resection is reserved for refractory stenosis.Keywords: congenital esophageal stenosis, esophageal atresia, esophageal stricture, tracheoesophageal fistul
Detection and tracking of discrete phenomena in sensor-network databases
This paper introduces a framework for Phenomena Detection and Tracking (PDT, for short) in sensor network databases. Examples of detectable phenomena include the propagation over time of a pollution cloud or an oil spill region. We provide a crisp definition of a phenomenon that takes into consideration both the strength and the time span of the phenomenon.We focus on discrete phenomena where sensor readings are drawn from a discrete set of values, e.g., item numbers or pollutant IDs, and we point out how our work can be extended to handle continuous phenomena. The challenge for the proposed PDT framework is to detect as much phenomena as possible, given the large number of sensors, the overall high arrival rates of sensor data, and the limited system resources. Our proposed PDT framework uses continuous SQL queries to detect and track phenomena. Execution of these continuous queries is performed in three phases; the joining phase, the candidate selection phase, and the grouping/output phase. The joining phase employs an in-memory multi-way join algorithm that produces a set of sensor pairs with similar readings. The candidate selection phase filters the output of the joining phase to select candidate join pairs, with enough strength and time span, as specified by the phenomenon definition. The grouping/ output phase constructs the overall phenomenon from the candidate join pairs. We introduce two optimizations to increase the likelihood of phenomena detection while using less system resources. Experimental studies illustrate the performance gains of both the proposed PDT framework and the proposed optimizations
Ultrasonographic evaluation of fetal lung histogram versus lamellar body count in the prediction of fetal lung maturity
Objective: The current study aims to compare the ultrasonographic evaluation of fetal lung Gray-level histogram width (GLHW) ratio with an amniotic fluid lamellar body count (LBC) in the prediction of fetal lung maturity.
Methods: A prospective cohort study was conducted at a tertiary University Hospital in the period between May 1, 2017 and March 31, 2018. The study included pregnant women with a single fetus at ≥37 weeks of gestation scheduled for delivery by elective cesarean section (CS). Ultrasound evaluation was performed for assessment of the fetal lung to liver GLHW ratio to predict lung maturity. Lamellar body count was determined from an amniotic fluid sample obtained via amniotomy during CS. The lamellar body count for this sample was measured using a hematology analyzer. These data were further compared to Apgar scores at 1 and 5 minutes after delivery to assess the condition of the newborn immediately after birth, the degree of respiratory distress syndrome (RDS) and the need for resuscitation.
Results: One hundred twenty women and their neonates were included in the study. There was a statistically significant decrease in the levels of both GLHW and LBC among those neonates that showed distressed respiration after Apgar testing as compared with those who did not show similar distress, with p-value <0.001. The Receiver Operating Characteristic Curve (ROC) for LBC levels in the prediction of respiratory distress shows the best cutoff point for LBC was found at ≤20214/μL with a sensitivity of 100.0%, specificity of 75.47% and area under the curve (AUC) of 88.4%. The ROC curve for GLWH levels in the prediction of respiratory distress shows the best cutoff point for GLWH was found at ≤0.93 with sensitivity of 100.0%, specificity of 84.91% and AUC of 97.1%.
Conclusions: Ultrasonographic evaluation of GLHW of the fetal lung and liver is a non-invasive, inexpensive and time-efficient test for prediction of fetal lung maturity that has higher sensitivity and specificity
QoS Categories Activeness-Aware Adaptive EDCA Algorithm for Dense IoT Networks
IEEE 802.11 networks have a great role to play in supporting and deploying of
the Internet of Things (IoT). The realization of IoT depends on the ability of
the network to handle a massive number of stations and transmissions, and to
support Quality of Service (QoS). IEEE 802.11 networks enable the QoS by
applying the Enhanced Distributed Channel Access (EDCA) with static parameters
regardless of existing network capacity or which Access Category (AC) of QoS is
already active. Our objective in this paper is to improve the efficiency of the
uplink access in 802.11 networks; therefore we proposed an algorithm called QoS
Categories Activeness-Aware Adaptive EDCA Algorithm (QCAAAE) which adapts
Contention Window (CW) size, and Arbitration Inter-Frame Space Number (AIFSN)
values depending on the number of associated Stations (STAs) and considering
the presence of each AC. For different traffic scenarios, the simulation
results confirm the outperformance of the proposed algorithm in terms of
throughput (increased on average 23%) and retransmission attempts rate
(decreased on average 47%) considering acceptable delay for sensitive delay
services.Comment: 17 pages, 10 figure
Shear Performance of GFRP Reinforced Concrete Beams with Seawater and Chopped Fiber
This paper reports an experimental study on the behavior and shear strength of concrete beams reinforced with longitudinal GFRP bars mixed with sea water. In order to evaluate how much concrete contributes to shear resistance, seven beams were tested in bending. Similar in size and concrete strength, the beams were longitudinally reinforced with glass fiber-reinforced polymer bars; however, they did not even have shear reinforcement. The beams, which measured 3,100 mm in length, 400 mm in depth, and 200 mm in width, were conducted and tested up to failure. The test variables were longitudinal reinforcement ratios (1.0, 1.4, and 2.0%), chopped fiber content (0, 0.5, 2, and 3 kg/m3), and mixing water type (freshwater and seawater). The test findings showed that increasing the reinforcement ratio increased the neutral-axis depth and allowed the formation of more closely spaced fractures while decreasing the loss of flexural stiffness after cracking. By increasing the area of concrete in compression, this in turn enhances the contribution of aggregate interlock as well as the contribution of uncracked concrete. Furthermore, increasing the reinforcement ratio improves the dowel action, which reduces the tensile stresses that are created in the concrete around it. Doi: 10.28991/CEJ-2023-09-04-05 Full Text: PD
Vehicle Active Suspension Control using Multi-order PID Approach
This paper presents the comparison among passive, proportional-integral-differential (PID) and multi-order PID (MOPID) controlled active suspensions. The quarter car model is validated with previous experimental results. The active suspension control via simulation is performed at three different frequency regions which are below natural frequency of body, in between natural frequency of body and wheel and above natural frequency of wheel. The parameters are tuned and Dormand-Prince solver is used in the simulation. The MOPID controller produces good performance in controlling vertical body displacement and acceleration thus improve ride performance and comfort
Optical humidity sensor based on tapered fiber with multi-walled carbon nanotubes slurry
We demonstrated performance comparison of optical humidity sensor for bare and Multi-walled carbon nanotubes (MWCNTs) slurry coated tapered optical fiber. The starting material for MWCNTs slurry is MWCNTs- acrylonitrile butadiene styrene (ABS) based fused deposition modeling (FDM) 3D printer filament. The ABS was dissolved using acetone to produce MWCNTs-acetone suspension. The MWCNTs-acetone suspension was drop-casted on the tapered fiber to produce MWCNTs slurry by evaporation process at room temperature, which resulted the MWCNTs slurry attach to the tapered fiber. The MWCNTs slurry acts as the cladding for humidity changes measurement. The experimental works showed improvement of sensitivity from 3.811 μW/% of bare tapered fiber to 5.17 μW/% for the coated tapered fiber with MWCNTs slurry when the humidity varied from 45% to 80%
Motor and Cerebellar Architectural Abnormalities during the Early Progression of Ataxia in a Mouse Model of SCA1 and How Early Prevention Leads to a Better Outcome Later in Life
Exposing developing cerebellar Purkinje neurons (PNs) to mutant Ataxin1 (ATXN1) in 82Q spinocerebellar ataxia type 1 (SCA1) mice disrupts motor behavior and cerebellar climbing fiber (CF) architecture from as early as 4 weeks of age. In contrast, if mutant ATXN1 expression is silenced until after cerebellar development is complete, then its impact on motor behavior and cerebellar architecture is greatly reduced. Under these conditions even 6 month old SCA1 mice exhibit largely intact motor behavior and molecular layer (ML) and CF architecture but show a modest reduction in PN soma area as a first sign of cerebellar disruption. Our results contrast the sensitivity of the developing cerebellum and remarkable resilience of the adult cerebellum to mutant ATXN1 and imply that SCA1 in this mouse model is both a developmental and neurodegenerative disorder
Acetaldehyde binding energies: a coupled experimental and theoretical study
Acetaldehyde is one of the most common and abundant gaseous interstellar
complex organic molecules, found in cold and hot regions of the molecular
interstellar medium. Its presence in the gas-phase depends on the chemical
formation and destruction routes, and its binding energy (BE) governs whether
acetaldehyde remains frozen onto the interstellar dust grains or not. In this
work, we report a combined study of the acetaldehyde BE obtained via laboratory
TPD (Temperature Programmed Desorption) experiments and theoretical quantum
chemical computations. BEs have been measured and computed as a pure
acetaldehyde ice and as mixed with both polycrystalline and amorphous water
ice. Both calculations and experiments found a BE distribution on amorphous
solid water that covers the 4000--6000 K range, when a pre-exponential factor
of is used for the interpretation of the experiments.
We discuss in detail the importance of using a consistent couple of BE and
pre-exponential factor values when comparing experiments and computations, as
well as when introducing them in astrochemical models. Based on the comparison
of the acetaldehyde BEs measured and computed in the present work with those of
other species, we predict that acetaldehyde is less volatile than formaldehyde,
but much more than water, methanol, ethanol, and formamide. We discuss the
astrochemical implications of our findings and how recent astronomical high
spatial resolution observations show a chemical differentiation involving
acetaldehyde, which can easily explained as due to the different BEs of the
observed molecules.Comment: 12 pages, 6 figure
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