34 research outputs found

    Influence of Low-Level Laser Modification and Adhesive Application Mode on the Bonding Efficiency of Universal Adhesives to Er:YAG Laser-Ablated Dentin

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    Introduction: Erbium laser ablation as a method of tooth preparation and conditioning has shown promising results. Although previous studies have adopted various combinations of different laser parameters and several dentin adhesive systems, very few have investigated combining high-level and low-level Er: YAG lasers with Universal adhesives. This study aimed to assess the impact of using low-energy irradiation on the surface micro-topography and shear bond strength (SBS) of universal adhesive (UA) to the erbium:yttrium-aluminum-garnet (Er: YAG) laser-ablated dentin substrate, bonded in etch-and-rinse or self-etch adhesive mode.Methods: Eighty-seven extracted molars were sectioned to expose flat occlusal dentin surface; 60 teeth were divided equally into three groups according to the surface treatment; bur-cutting (B), Er: YAG high-energy laser cutting, or L1 followed by low-energy laser modification. Then each group was equally divided into two groups (n=10) according to the mode of application of the universal adhesive; either etch-and-rinse (ER) or self-etching (SE). The samples were subjected to thermocycling (5000 cycles between 5°C and 55°C), and SBS was tested. Two-way ANOVA and Tukey post hoc test was used to analyze the results. The remaining 27 samples were used to investigate the effect of the treatment on the topography of the treated dentin surfaces using a scanning electron microscope (SEM).Results: B/SE recorded the highest SBS (25.48 ± 2.6 MPa) followed by B/ER and L1/L2/SE (22.94 ± 4.1 MPa) and with no statistically significant difference between these groups (P >0.05). The lowest SBS results (P<0.05) were recorded for L1/SE (12.22 ± 3 MPa). No statistical differences were found between the SBS of L1/L2/ER and L1/ER groups or between the SBS of L1/L2/ER and L1/L2/SE groups.Conclusion: A subsequent treatment of the Er: YAG laser-ablated dentin with low-energy laser modification mode (LMM) enhances the SBS of the tested UA when applied in SE mode. DOI:10.34172/jlms.2021.0

    Computer Numerical Control CNC Machine Health Prediction using ‎Multi-domain Feature Extraction and Deep Neural Network Regression

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    Tool wear monitoring has become more vital in intelligent production to enhance Computer Numerical Control CNC machine health state. Multidomain features may effectively define tool wear status and help tool wear prediction. Prognostics and health management (PHM) plays a vital role in condition-based maintenance (CBM) to prevent rather than detect malfunctions in machinery. This has great advantage of saving costs of fault repair including human effort, financial costs as long as power and energy consumption. The huge evolution of Industrial Internet of Things (IIOT) and industrial big data analytics has made Deep Learning a growing field of research. The PHM society has held many competitions including PHM10 concerning CNC milling machine cutters data for tool wear prediction The purpose of this paper is to predict tool wear of CNC cutters and. We adopted a multi-domain feature extraction method for health statement of the cutters. and a deep neural network DNN method for tool wear prediction

    Allelic Discrimination of Vitamin D Receptor Polymorphisms and Risk of Type 2 Diabetes Mellitus: A Case-Controlled Study

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    (1) Background: Type 2 diabetes mellitus (T2DM) is one of the rapidly growing healthcare problems, and several vitamin D receptor (VDR) polymorphisms seem to modulate the risk of T2DM. Our research was designed to investigate the allelic discrimination of VDR polymorphisms and T2DM occurrence risk. (2) Methods: This case-control research included 156 patients with T2DM and 145 healthy control subjects. Most of the study population were males 56.6% vs. 62.8% in the case and control groups, respectively. Genotyping for VDR single nucleotide polymorphisms (SNPs), rs228570 (Fok1), rs7975232 (Apa1), and rs1544410 (Bsm1) was compared between both groups. (3) Results: There was a negative link between vitamin D levels and insulin sensitivity. A significant difference was noted in the allelic discrimination of VDR polymorphism rs228570 and rs1544410 between the study groups (p \u3c 0.001). No difference was observed in the allelic discrimination of VDR polymorphism rs7975232 between the groups (p = 0.063). Moreover, T2DM patients had significantly higher levels of fasting blood sugar (FBS), glycated hemoglobin HbA1c, 2-h post-prandial blood sugar (PP), serum glutamic oxaloacetic transaminase (SGOT), serum glutamic-pyruvic transaminase (SGPT), total cholesterol, and triglycerides (p \u3c 0.001), while High-Density Lipoprotein (HDL) Cholesterol (HDL-C) was significantly decreased (p = 0.006). (4) Conclusions: VDR polymorphisms had a positive association with T2DM risk among the Egyptian population. Further large-scale research using deep sequencing of samples is strongly urged to investigate different vitamin D gene variants and interactions, as well as the influence of vitamin D on T2DM

    Islet Gene View-a tool to facilitate islet research

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    Characterization of gene expression in pancreatic islets and its alteration in type 2 diabetes (T2D) are vital in understanding islet function and T2D pathogenesis. We leveraged RNA sequencing and genome-wide genotyping in islets from 188 donors to create the Islet Gene View (IGW) platform to make this information easily accessible to the scientific community. Expression data were related to islet phenotypes, diabetes status, other islet-expressed genes, islet hormone-encoding genes and for expression in insulin target tissues. The IGW web application produces output graphs for a particular gene of interest. In IGW, 284 differentially expressed genes (DEGs) were identified in T2D donor islets compared with controls. Forty percent of DEGs showed cell-type enrichment and a large proportion significantly co-expressed with islet hormone-encoding genes; glucagon (GCG, 56%), amylin (IAPP, 52%), insulin (INS, 44%), and somatostatin (SST, 24%). Inhibition of two DEGs, UNC5D and SERPINE2, impaired glucose-stimulated insulin secretion and impacted cell survival in a human beta-cell model. The exploratory use of IGW could help designing more comprehensive functional follow-up studies and serve to identify therapeutic targets in T2D.Peer reviewe

    Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017

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    A double burden of malnutrition occurs when individuals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4% (62.3 (55.1–70.8) million) to 6.4% (58.3 (47.6–70.7) million), but is predicted to remain above the World Health Organization’s Global Nutrition Target of <5% in over half of LMICs by 2025. Prevalence of overweight increased from 5.2% (30 (22.8–38.5) million) in 2000 to 6.0% (55.5 (44.8–67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic

    Energy efficiency opportunities in Hotels

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    <p>According to the statistics in Egypt (2013), the number of hotels is 1193, about 407 of them have contracted power greater than 500 kW.</p><p>Air conditioning, lighting, water heating and refrigeration represent the main activities demanding electrical energy in hotel business.</p><p>The energy consumption per night spend changes a lot, depending on various factors; facilities provided, category of hotel, occupancy , geographical situation, weather conditions, nationality of clients, design and control of the installations.</p><p>Energy benchmarking is an internal management tool designed to provide ongoing, reliable and verifiable tracking on the hotels performance. The most useful performance indicator (or Energy Efficiency Benchmarking) of hotels are: Lighting Power Density (LPD) in W (for lighting)/m2, and energy intensity (kWh/m2/ y).</p><p>There are multiple benefits for improving energy in hotel business; reduces the hotel's operating cost, reduces climate change risks and promotes green tourism.</p><p>Energy efficiency opportunities are low-cost measures and cost- effective investments.   </p><p>There are many energy saving opportunities for lighting in hotel's guest rooms as well as the more obvious savings in lobbies and exterior lighting areas. Behavior campaigns can yield substantial energy savings, both through the guests and housekeeper behavior. Encouraging housekeepers to use natural light during room cleaning is a simple first step to implement energy saving program.</p><p>This paper presents the energy efficiency guidelines and energy benchmarking for hotels. Also a case study showing how the energy efficiency program implemented is presented.</p><p><strong> </strong></p

    Highlight of Grid-connected PV systems in administrative buildings in Egypt

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    <p class="Abstract">Solar energy applications are becoming increasingly common in Egypt. The abundant sunshine in Egypt, as well as the increasing competitiveness of solar energy systems including- but not limited to photovoltaic (PV), – predicts that these technologies could be weighed to be raised in Egypt.</p><p class="Abstract">PV systems are installed on roof tiles or other parts of building structures to supplement grid utility, reduce electric bills, and provide emergency back–up energy. Moreover, they simultaneously reduce significant amounts of CO<sup>2</sup> emissions. It is foreseen, a number of residential and public buildings in Egypt are using solar power to cut electric utility bills significantly. The approximately payback period to recover the investment costs for PV systems is up to about 5 years.  In addition, it is more economical to use PV system than grid utility systems. The two components that determine the total initial price of a grid- connected PV system are the modules and the balance of systems (BOS). The BOS includes different components such as mounting frames, inverters and site- specific installation hardware.</p><p>The Government of Egypt (GOE) has endorsed the deployment of PV systems through three approaches. It started with a prime minister decree to install PV projects on one-thousand of the governmental buildings. This was followed by as an initiative called "Shamsk ya Masr", and finally the Feed-in Tariff (FiT) projects.</p><p>Following the prime minster decree the Egyptian Electricity Holding Company (EEHC) and its affiliated companies took the lead to install PV systems at the top roof of their administrative buildings and interconnect these systems to the electricity network where the suitable locations have been selected for mounting them. About 90 PV systems have been already mounted with about a capacity of 9 MW. On the other hand, "Shamsk ya Masr" has considered energy efficiency (EE) so as to complement the PV systems, which will be installed on administrative buildings. Cost- effective EE measures should be implemented prior to or at the same time as implemented PV program. The amount of electricity that a PV system produces depends on the system type, orientation and the available solar resource. In 2014, the GOE issued the Feed-in Tariff program to further promote RE technologies in general and PV in particular. Egyptian Electric Utility and Consumer Protection Regulatory Authority (Egypt ERA) has set the regulations, promotion and awareness for PVs. This approach has been applied for administrative buildings as well.</p><p>The paper highlights the impact of the previously mentioned mechanisms in deploying PV technologies through small scale projects. It also represents a cost- benefit analysis for the installed systems taking into account the measured value for PV parameters (kWh/kWp, PSH) and daily load profiles of the selected administrative buildings.</p

    Assessing the impact of converting roundabouts to traffic signals on vehicle emissions along an urban arterial corridor in Qatar.

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    The type of control at intersections has a major effect on the operation of any urban corridor. Different pre-defined procedures are available to calculate some of the main operational characteristics, such as capacity, delay, and level of service in order to select the best type of control. However, there are other important factors that affect major arterials operational characteristics, which are not fully addressed, such as the impact of emissions. In this study, a microscopic simulation approach using VISSIM and MOVES was developed to assess the environmental effect of converting four three-lane roundabouts to signalized intersections along a heavily congested urban corridor in Qatar. A decision was made to switch all roundabouts to traffic signals for better operations. Preliminary results indicated that the signal control outperformed the roundabout in the range of 37% to 43% reduction in emissions. A more detailed analysis revealed that roundabout corridor operations effect on emission rates are divergent from signalized corridors, particularly upstream and downstream of the intersections. Immediate roundabout upstream approaches are driver behavior dependent; characterized by substantial coasting at lower speeds and subsequent re-accelerating with less idling, described as acceleration events, which resulted in high emission rates while signalized corridors' s are signal timing dependent; characterized by ample idling with less coasting and re-acceleration, resulting in reduced emission rates. The results also revealed that there was no significant difference between emission rates in the vicinity of the two types of control. Both recorded nearly the same emission rate

    Retropupillary fixation of iris-claw intraocular lens versus trans-scleral suturing fixation for aphakic eyes without capsular support

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    Purpose The aim of this work was to compare retropupillary fixation of an iris-claw intraocular lens (IOL) (Verisyse) with trans-scleral suturing fixation for aphakic eyes without sufficient capsular support as regards the safety and complications of the procedure. Design This study was an interventional comparative prospective one. Patients and methods A total of 42 aphakic eyes of 40 patients were divided into two equal groups: 21 eyes were offered iris-claw IOL and 21 eyes were implanted with scleral-fixed IOL. Intraoperative data (mainly surgical time and intraoperative bleeding) and postoperative data [mainly corrected distance visual acuity (CDVA), intraocular pressure, and postoperative complications] were compared between the two groups during the follow-up period (first day,1 week, 2 weeks,1 month, and after 3 months). Results The mean surgical time in the iris-claw group was 24.77 ± 4.8 min, whereas the mean surgical time in the scleral fixation group was 67.09 ± 8.1 min, with a statistically significant difference between the two groups. On the first postoperative day, the CDVA ranged from 0.06 to 0.5 in the iris-claw group, with a mean of 0.22 ± 0.116, and it ranged from 0.05 to 0.15 in the scleral fixation group, with a mean of 0.10 ± 0.032; there was a statistically significant difference between the groups (P = 0.00021). However, after the first 3 months postoperatively, the CDVA ranged from 0.25 to 1.0 in the iris-claw group, with a mean of 0.51 ± 0.25, and it ranged from 0.15 to 0.6 in the scleral fixation group, with a mean of 0.42 ± 0.16; there was no statistically significant difference between the two groups (P = 0.152). On the first postoperative day, the mean intraocular pressure in the iris-claw group was 15.62 ± 2.59 mmHg, whereas in the scleral fixation group it was 19.62 ± 3.94 mmHg, with a statistically significant difference between the two groups (P = 0.00038). The iris-claw group showed higher rates of anterior chamber reaction, pupillary distortion, and cystoid macular edema postoperatively. In contrast, the rates of corneal edema, vitreous hemorrhage, and conjunctival erosion were higher in the scleral fixation group. Conclusion From our results, it is evident that iris-claw IOLs have now matured to a stage when they can be used with considerable safety and efficacy. The new designs, as well as the evolution of surgical techniques and instrumentation, have made them the best option for primary or secondary implantation in aphakic eyes. The surgical procedure is easier, shorter, and safer than those used for scleral-sutured IOLs
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