40 research outputs found
Ameloplasty is counterproductive in reducing microleakage around resin modified glass ionomer and resin based fissure sealants
Objective: To compare the microleakage around resin modified glass ionomer cement (RMGIC) based sealants and flowable resin based sealants placed with or without ameloplasty in extracted human teeth.Methods: This in-vitro experimental study was conducted at the Operative Dentistry Department, Dow University of Health Sciences, Karachi, Pakistan from June 2017 to December 2018. Sixty extracted human molars and premolars were assigned to four groups (n=15) each, according to the type of fissure sealant (flowable resin based sealant or resin modified glass ionomer based sealant) used and either placed with or without ameloplasty. Specimens were thermocycled and then immersed in 1% methylene blue for 24 hours. Specimens were then sectioned and examined using stereo-microscope (50X) for microleakage that was scored on an ordinal scale. Mann-Whitney U test and Ordinal regression were applied. Level of significance kept at 0.05.Results: There was a statistically significant difference (p-value \u3c0.001) between the two sealant types for the microleakage scores. Sealants placed with ameloplasty demonstrated significantly higher microleakage values (p-value \u3c0.001).Conclusion: Microleakage was found to be more pronounced in RMGIC based sealants compared to the resin based sealants. Ameloplasty resulted in higher leakage around the sealants irrespective of the chemistry of material
Incast mitigation in a data center storage cluster through a dynamic fair-share buffer policy
Incast is a phenomenon when multiple devices interact with only one device at a given time. Multiple storage senders overflow either the switch buffer or the single-receiver memory. This pattern causes all concurrent-senders to stop and wait for buffer/memory availability, and leads to a packet loss and retransmissionâresulting in a huge latency. We present a software-defined technique tackling the many-to-one communication patternâIncastâin a data center storage cluster. Our proposed method decouples the default TCP windowing mechanism from all storage servers, and delegates it to the software-defined storage controller. The proposed method removes the TCP saw-tooth behavior, provides a global flow awareness, and implements the dynamic fair-share buffer policy for end-to-end I/O path. It considers all I/O stages (applications, device drivers, NICs, switches/routers, file systems, I/O schedulers, main memory, and physical disks) while achieving the maximum I/O throughput. The policy, which is part of the proposed method, allocates fair-share bandwidth utilization for all storage servers. Priority queues are incorporated to handle the most important data flows. In addition, the proposed method provides better manageability and maintainability compared with traditional storage networks, where data plane and control plane reside in the same device
Designing of Different High Efficiency Diode Clamped Multilevel
This research work is aimed at designing of high efficiency multilevel diode clamped inverter. It would cover diode clamped multilevel inverter with particular reference to the comparison of high level and low level inverter using efficient modulation method (sinusoidal pulse width modulation). The main theme of this research is to obtain a pure sinusoidal waveform of high quality having minimum harmonics that can be utilized for both industrial purposes and to sensitive domestic loads. The proposed design besides considering high quality of the output waveform of multilevel diode clamped inverter, the problems regarding multilevel inverter design has been given more consideration high voltage stresses across switching devices. The voltage stresses issues have been resolved with DC link voltage equally distributed among capacitors in multilevel inverter. Simulation results for different level inverters both low level (5, 7, 9, level) and high levels (11, 13, 15) are used as a reference. The proposed design resulted in reduced total harmonic distortion thus eliminating the harmonics in the output waveform to a greater extent resulting in pure sine waveform output. This resulted in reduction in overall losses and elimination of voltage balancing problems in high level diode clamped inverter. Keywords: Hormonics, Clamping, Inverter, Pulse Width Modulation, Sinusoidal Pulse Width Modulation (SPWM)
Mapping flood prone and Hazards Areas in rural landscape using landsat images and random forest classification: Case study of Nasia watershed in Ghana
Floods are hazard which poses immense threat to life and property. Identifying flood-prone areas, will enhance flood mitigation and proper land use planning of affected areas. However, lack of resources, the sizable extent of rural settlements, and the evolving complexities of contemporary flood models have hindered flood hazard mapping of the rural areas in Ghana. This study used supervised Random Forest (RF) classification, Landsat 8 OLI, and Landsat 7 ETM + images to produce flood prone, Land Use Land Cover (LULC), and flood hazard maps of the Nasia Watershed in Ghana. The results indicated that about 418.82 km2 area of the watershed is flooded every 2â3 years (normal flooding) and about 689.61 km2 is flooded every 7â10 years (extreme flooding). The LULC classification produced an overall accuracy of 92.31% and kappa of 0.9. The flood hazard map indicated that land areas within hazard zones of the river include the Nasia community, Flood Recession Agricultural (FRA), rainfed and woodlands. When compared with a Modified Normalized Difference Water Index (MNDWI), the RF supervised classification had an edge over the MNDWI in estimating the flooded areas. The results from this study can be used by local administrators, national flood disaster management and researchers for flood mitigation and land use planning within the watershed
A metasurface-based single-layered compact AMC-backed dual-band antenna for off-body IoT devices
In this article, a compact printed monopole dual-band antenna using artificial magnetic conductor (AMC)-plane with improved gain and broader bandwidth, applicable for off-body internet of things (IoT) devices is presented. The monopole antenna consists of two C-shaped resonators connected through a U-shaped monopole, parasitic elements, discrete ground circular rings and a co-planar waveguide (CPW) feedline. Each artificial magnetic conductor (AMC) unit cell consists of a slotted circular and a square stubs, designed with two zero-crossing phases for improving the radiation characteristics and to achieve the high gain. The overall size of the proposed AMC-backed antenna is 44.4 mm Ă44.4 mm Ă1.6 mm with electrical dimensions of 0.75λ g Ă 0.75λ gĂ 0.027λ g. This AMC-backed antenna featured measured bandwidths of 9.6% and 12.4% with improved measured gain values of 4.88 dB and 4.73 dB at 2.45 GHz and 5.8 GHz, respectively. The specific absorption rate (SAR) values are analysed and found to be 1.58 W/kg at 2.45 GHz and 0.9 W/kg at 5.8 GHz. Therefore, the proposed AMC-backed antenna is useful for off-body IoT devices operating at 2.45 and 5.8 GHz industrial, scientific, and medical (ISM) band applications.This work was supported in part by the Universidad Carlos III de Madrid; in part by the European Unionâs Horizon 2020 Research and Innovation Programme under Marie Sklodowska-Curie Grant 801538; in part by the Ministerio de Ciencia, InnovaciĂłn y Universidades, Gobierno de España (MCIU/AEI/FEDER and UE) under Grant RTI2018-095499-B-C31; and in part by the Researchers Supporting Project, King Saud University, Riyadh, Saudi Arabia, under Project number RSP-2021/58
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Mortality in Hip Fracture Patients During the COVID-19 Pandemic: A Retrospective Analysis in a District General Hospital in the United Kingdom
Introduction
Hip fracture is commonly seen in elderly patients because of low-energy trauma. It carries significant morbidity and mortality. Scoring systems such as the Nottingham hip fracture score (NHFS) have shown a good correlation with increased mortality as the value of these scores increases. In our study, we aim to ascertain the hip fracture mortality in our population, compare the mortality in hip fractures compared to previously reported figures in literature and nationally reported figures during the first year of the COVID-19 pandemic, and also ascertain the usefulness of NHFS in predicting mortality in hip fractures.
Methods
We gathered mortality data on hip fracture patients admitted to our unit from January 1, 2020 to December 31, 2020. NHFS was calculated for all patients and the 30-day mortality rate was compared to previously reported hip fracture mortality rates using the standard mortality ratio (SMR). One-year mortality was stratified by placing patients in high and low NHFS groups. The log-rank test was used to compare hip fracture survival at one month and at one year in the high NHFS (NHFS >4) group and low NHFS group (NHFS value 4 or below). Additionally, a log-rank test was used to compare one-month and one-year survival in hip fractures managed with hemiarthroplasty, dynamic hip screw and intramedullary nail.
Results
In 2020, 388 patients were admitted with hip fractures to our unit. The crude mortality rate was 3.9% at 30 days and 20.88% at one year. Compared to the National Hip Fracture Database report for 2020, the incidence risk ratio for mortality was 0.46 (p-value<0.05). The SMR at 30 days was 0.34 (CI=0.17-0.51) and the SMR at one year was 0.63 (CI=0.49-0.77). The survival rate was higher at 30 days and one year in the low NHFS group compared to the high NHFS group (p-value<0.01). The survival rate at one month and one year were similar in groups managed with hemiarthroplasty, dynamic hip screws, and intramedullary nails (p-value>0.05).
Conclusions
Hip fracture mortality has been decreasing steadily and we noted a lower rate of hip fracture mortality compared to figures reported previously as per NHFS studies even though the study was conducted during the COVID-19 pandemic period. We also noted lower 30-day mortality in our hospital as compared to the national 30-day mortality rate for hip fracture patients in 2020.
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Impact of COVID-19 Pandemic on the Length of Hospital Stay in Hip Fracture Patients: A Single Centre Study
Background
Hip fracture is a debilitating injury, especially in older individuals, which is associated with significant morbidity and mortality. In recent decades, there has been a great focus on early rehabilitation and discharge after hip fractures. The aim of such efforts is to minimize the financial and clinical burden of this condition. We conducted our study during the COVID-19 pandemic and compared the length of hospital stay (LOS) in 2020 to the LOS in 2019. Additionally, we studied the factors which may impact the LOS, such as premorbid status according to established scoring systems, the type of fracture, an operation performed, and time to surgery.
Methods
We collected the data regarding the length of stay (in days) for all hip fracture patients admitted to our unit from 1st January 2019 until 31st December 2020. We then compared the mean LOS for both years using the t-test. We calculated the Nottingham Hip Fracture Score (NHFS) and American Society of Anaesthesiologists (ASA) scores for patients admitted in 2020 and calculated the correlation between increasing values of these scores and the LOS. We also compared the mean LOS for patients admitted in 2020 based on the type of fracture and type of management. We studied the correlation between the time to surgery and the LOS for patients admitted in 2020.
Results
Three hundred and eighty-eight patients were admitted with hip fractures in 2020, and 452 were admitted in 2019. LOS in 2020 was significantly lower (23.39 days) compared to 2019 (31.36 days) with p<0.01. While evaluating data from 2019, it was noted that there was a small positive correlation between LOS and NHFS (r=0.231, p<0.001) and LOS and ASA (r=0.18, p<0.001). The mean LOS for intracapsular fractures was noted to be lower than that of extracapsular fractures, but this was not statistically significant (p=0.17). An ANOVA test showed that the mean LOS for patients undergoing hemiarthroplasty, dynamic hip screws (DHS), and intramedullary nails (IMN) was significantly longer than for patients managed with total hip replacement or patients managed non-operatively (F=3.551, p<0.01).
Conclusion
Hip fracture patients admitted to our department were discharged quicker during the first year of the COVID-19 pandemic. The LOS for hip fractures increases with an increase in their NHFS or ASA scores. Extracapsular and intracapsular fractures lead to roughly the same periods of inpatient stay. Patients undergoing hemiarthroplasty, DHS, or IMN stay longer in the hospital compared to other treatment modalities.</p
Watershed prioritization and hydro-morphometric analysis for the potential development of Tabuk Basin, Saudi Arabia using multivariate statistical analysis and coupled RS-GIS approach
The Tabuk province of Saudi Arabia (SA) has an arid zone, few aquifers, high groundwater salinity (seawater intrusion), and accelerated population, industrial, and agricultural development. The development of Tabuk Basin is essential for the addition of new freshwater resources and the enhancement of aquifer recharge potential. The hydrological characteristics of the drainage basin aid in the identification of watersheds, enabling the protection and management of land erosion and ground/surface water resources. This study analyzed hydro-morphometric data from the eighteen sub-basins of the Tabuk Basin using multivariate statistical approaches and coupled remote sensing (RS) and geographic information systems (GIS) for water priority determination. The results show that the four principal components (PC1-4) have a variance of 90.4% concerning bifurcation ratio (Rb), ruggedness number (Rn), elongation ratio (Re), drainage density (Dd), basin relief (Bh), circularity ratio (Rc), and relief ratio (Rh). The Al Ula, Thaibah, Hamd, Dama, Al Wajh, Al Ghamra, and Azlam sub-basins showed the highest priority, indicating soil erosion and the necessity for mitigating measures to reduce infrastructure damage. Most exposed geology (67%) exhibited strong permeability and good infiltration (sedimentary cover and Quaternary sediments). The rest (23%) showed low to medium permeability (igneous, metamorphic, and carbonate rocks). The best promising sites for building new wells can reduce surface runoff and soil erosion through aquifer infiltration and abstraction. The aquifer potentiality map was accomplished for Al Ula, Thaibah, Hamd, and Dama drainage basins. The most prospective groundwater investigation regions were identified, coinciding with the drilled wells that confirmed and validated the results. The estimated zones of high to very high aquifer potentiality were used to add additional wells for investment reduce soil erosion, mitigate alternatives, agriculture, urbanization, etc. The other sub-basins have a medium to low priority, with less soil erosion and aquifer recharge
Crop Water Requirements with Changing Climate in an Arid Region of Saudi Arabia
Agriculture is critical for a country’s population growth and economic expansion. In Saudi Arabia (SA), agriculture relies on groundwater, seasonal water, desalinated water, and recycled water due to a lack of surface water resources, a dry environment, and scanty rainfall. Estimating water consumption to plan crop water requirements (CWR) in changing environments is difficult due to a lack of micro-level data on water consumption, particularly in agricultural systems. High-resolution satellite data combined with environmental data provides a valuable tool for computing the CWR. This study aimed to estimate the CWR with a greater spatial and temporal resolution and localized field data and environmental variables. Obtaining this at the field level is appropriate, but geospatial technology can produce repeatable, time-series phenomena and align with environmental data for wider coverage regions. The CWR in the study area has been investigated through two methods: firstly, based on the high-resolution PlanetScope (PS) data, and secondly, using the FAO CROPWAT model v8.0. The analysis revealed that evapotranspiration (ETo) showed a minimum response of 2.22 mm/day in January to a maximum of 6.13 mm/day in July, with high temperatures (42.8). The humidity reaches a peak of 51%, falling to a minimum in June of 15%. Annual CWR values (in mm) for seven crops studied in the present investigation, including date palm, wheat, citrus, maize, barley, clover, and vegetables, were 1377, 296, 964, 275, 259, 1077, 214, respectively. The monthly averaged CWR derived using PS showed a higher correlation (r = 0.83) with CROPWAT model results. The study was promising and highlighted that such analysis is decisive and can be implemented in any region by using Machine Learning and Deep Learning for in-depth insights
Crop Water Requirements with Changing Climate in an Arid Region of Saudi Arabia
Agriculture is critical for a countryâs population growth and economic expansion. In Saudi Arabia (SA), agriculture relies on groundwater, seasonal water, desalinated water, and recycled water due to a lack of surface water resources, a dry environment, and scanty rainfall. Estimating water consumption to plan crop water requirements (CWR) in changing environments is difficult due to a lack of micro-level data on water consumption, particularly in agricultural systems. High-resolution satellite data combined with environmental data provides a valuable tool for computing the CWR. This study aimed to estimate the CWR with a greater spatial and temporal resolution and localized field data and environmental variables. Obtaining this at the field level is appropriate, but geospatial technology can produce repeatable, time-series phenomena and align with environmental data for wider coverage regions. The CWR in the study area has been investigated through two methods: firstly, based on the high-resolution PlanetScope (PS) data, and secondly, using the FAO CROPWAT model v8.0. The analysis revealed that evapotranspiration (ETo) showed a minimum response of 2.22 mm/day in January to a maximum of 6.13 mm/day in July, with high temperatures (42.8). The humidity reaches a peak of 51%, falling to a minimum in June of 15%. Annual CWR values (in mm) for seven crops studied in the present investigation, including date palm, wheat, citrus, maize, barley, clover, and vegetables, were 1377, 296, 964, 275, 259, 1077, 214, respectively. The monthly averaged CWR derived using PS showed a higher correlation (r = 0.83) with CROPWAT model results. The study was promising and highlighted that such analysis is decisive and can be implemented in any region by using Machine Learning and Deep Learning for in-depth insights