Post-hemorrhagic ventricular dilatation (PHVD) in preterm infants can be assessed with ventricular size indices from cranial ultrasound. We explored inter-observer reliability of these indices for ...prediction of severe PHVD.
For all 139 infants with IVH, serial neonatal ultrasound at 3 time points (days 4-7, day 14, 36 weeks PMA) were assessed independently by 3 observers with differing levels of training/experience. Ventricular index (VI), anterior horn width (AHW), and fronto-temporal horn ratio (FTHR) were measured and used to diagnose PHVD. For all, inter-observer reliability and predictive values for receipt of surgical intervention were calculated.
Inter-observer reliability for all observers varied from poor to excellent, with higher reliability for VI/AHW (ICC 0.49-0.84/0.51-0.81) than FTHR (0.41-0.82), particularly from the second week. Good-excellent inter-expertise reliability was found between observers with ample experience/training (0.65-0.99), particularly for VI and AHW, while poor-moderate when comparing with an inexperienced observer (0.28-0.88). Slightly higher predictive value for PHVD intervention (n = 12) was found for AHW (AUC 0.86-0.96) than for VI and FTHR (0.80-0.96/0.80-0.95).
AHW and VI are highly reproducible in experienced hands compared to FTHR, with AHW from the second week onwards being the strongest predictor for receiving surgical intervention for severe PHVD. AHW may aid in early PHVD diagnosis and decision-making on intervention.
While ventricular size indices from serial cUS are superior to clinical signs of increased intracranial pressure to assess PHVD, questions remained on their inter-observer reproducibility and reliability to predict severity of PHVD. AHW and VI are highly reproducible when performed by experienced clinicians. AHW from the second week of birth is the strongest predictor of PHVD onset and severity. AHW, combined with VI, may aid in early PHVD diagnosis and decision-making on need for surgical intervention. Consistent use of these indices has the potential to improve PHVD management and therewith the long-term outcomes in preterm infants.
In this paper, a modern non-contacting optical technique was used to study the surface roughness of commercially pure copper. Finite element (FE) method was applied to predict the stress during ...orthogonal cutting by simulating the machining process. The experimental work empathized mainly on the effect of cutting speed (N) and feed rate (f) on the surface roughness of copper. Scanning electron microscope (SEM) was utilized to evaluate the surface variations at different machining conditions. Johnson-Cook mathematical model was adopted and employed to determine the parameters of the material. Furthermore, the maximum Von-Mises stress was predicted as a function of machining conditions. A software package of code (ABAQUS/CAE) was used for the analysis and response surface methodology (RSM) was applied to visualize the results. The results showed a significant effect of the feed rate/cutting speed interaction on surface roughness and Von-Mises stress of copper. An enhancement of 14% in surface roughness was perceived with increasing the cutting speed. A good agreement was observed between experimental and analytical results.
Even though water is a renewable resource, the majority of the available water on the planet is unfit for human use. Moreover, the drinkable water demand is ever-increasing as a result of rising ...population, urbanization, and life standards, which makes the needs for sustainable, economic, and environment-friendly treatment alternatives of utmost importance. Seawater desalination using solar stills has been proposed as a promising alternative that may help to solve drinkable water scarcity issues. In the past decades, many studies have been conducted to assess the performance of different types of solar stills aiming to enhance their productivity. Computational fluid dynamic (CFD) numerical simulation is one of the approaches that have been used recently to assess the performance of solar stills. The present study performed a systematic review and bibliometric analysis to provide a comprehensive overview of CFD numerical simulation uses as a tool to assess solar stills performance. A total of 486 publications were collected initially from different databases for the period between 2012 and 2022. The collected publications were filtered through several stages reaching 43 publications of highest significance. The collected data were analyzed descriptively, and the bibliometric mapping was presented. Furthermore, the basics and principles of CFD numerical simulation of solar stills efficiency were described and discussed. Later, the previous studies were analyzed to understand the algorithms, methods, and still types used. Finally, future research scopes and conclusions were stated. The presented knowledge in this study can help to provide a deep overview of using CFD in studying the efficiency of solar stills and inspire researchers to identify future research ways and gaps.
Deep drawing is characterized by extremely complex deformation that is influenced by process characteristics such as die and punch shapes, blank shape, blank holding force, material properties, and ...lubrication. The optimization of the deep drawing process is a challenging issue due to the complicated functions that define and relate the process parameters. However, the optimization is essential to enhance the productivity and the product cost in the deep drawing process. In this paper, a MATLAB toolbox (Pattern Search) was employed to minimize the maximum deep drawing force (Fd-min) at different values of the operating and the geometrical parameters. As a result, a minimum deep drawing force chart (carpet plot) was generated to show the best combination of friction coefficients at the blank contact interfaces. The extracted friction coefficients guided the selection of proper lubricants while minimizing the deep drawing force. A finite element analysis (FEA) was applied through 3D model to simulate the deep drawing process. The material modeling was implemented utilizing the ABAQUS/EXPLICIT program with plastic anisotropy. The optimization results showed that the deep drawing force and the wrinkling decrease when compared with experimental and numerical results from the literature.
Acquired brain injury remains common in very preterm infants and is associated with significant risks for short- and long-term morbidities. Cranial ultrasound has been widely adopted as the ...first-line neuroimaging modality to study the neonatal brain. It can reliably detect clinically significant abnormalities that include germinal matrix and intraventricular hemorrhage, periventricular hemorrhagic infarction, post-hemorrhagic ventricular dilatation, cerebellar hemorrhage, and white matter injury. The purpose of this article is to provide a consensus approach for detecting and classifying preterm brain injury to reduce variability in diagnosis and classification between neonatologists and radiologists. Our overarching goal with this work was to achieve homogeneity between different neonatal intensive care units across a large country (Canada) with regards to classification, timing of brain injury screening and frequency of follow up imaging. We propose an algorithmic approach that can help stratify different grades of germinal matrix-intraventricular hemorrhage, white matter injury, and ventricular dilatation in very preterm infants.
The effect of catalyst calcination temperature on the uniformity of carbon nanotubes (CNTs) diameter synthesized by the decomposition of methane was studied. The catalysts used were CoO–MoO/Al
2O
3 ...without prior reduction in hydrogen. The results show that the catalyst calcination temperature greatly affects the uniformity of the diameter. The CNTs obtained from CoO–MoO/Al
2O
3 catalysts, calcined at 300
°C, 450
°C, 600
°C, and 700
°C had diameters of 13.4
±
8.4, 12.6
±
5.1, 10.7
±
3.2, and 9.0
±
1.4
nm, respectively, showing that an increase in catalyst calcination temperature produces a smaller diameter and narrower diameter distribution. The catalyst calcined at 750
°C was inactive in methane decomposition. Transmission electron microscopy (TEM) studies showed that CNTs grown on the catalyst calcined at 700
°C were of uniform diameter and formed a dense interwoven covering. High-resolution TEM shows that these CNTs had walls of highly graphitized parallel graphenes.
Hydroxyapatite is a biocompatible material that is extensively used in the replacement and regeneration of bone material. In nature, nanostructured hydroxyapatite is the main component present in ...hard body tissues. Hence, the state of the art in nanotechnology can be exploited to synthesize nanophase hydroxyapatite that has similar properties with natural hydroxyapatite. Sustainable methods to mass-produce synthetic hydroxyapatite nanoparticles are being developed to meet the increasing demand for these materials and to further develop the progress made in hard tissue regeneration, especially for orthopedic and dental applications. This article reviews the current developments in nanophase hydroxyapatite through various manufacturing techniques and modifications.
Catalyst reduction temperature was observed to affect the yield and diameter uniformity of carbon nanotubes (CNTs) produced on Co-Mo/Al2O3 catalysts. The results show that on the whole, the reduced ...catalysts gave higher carbon yield. The CNTs obtained from the unreduced catalyst and the catalysts reduced at 400, 550, and 700 deg C had diameters of 9.0+/-1.4, 11.0+/-1.8, 11.2+/-1.8, and 12.1+/-2.7nm, respectively, showing that an increase in catalyst reduction temperature produced a slightly larger average diameter and wider diameter distribution. Raman spectra further elucidate that better-graphitized CNTs were produced on the catalysts reduced with increasing reduction temperatures.
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