2,880 research outputs found
Seismic Response of Floating Piles to Obliquely Incident Waves
The response of single piles under vertically and obliquely incident SH, SV, and P waves is obtained using a hybrid boundary element (BEM) formulation. The piles are represented by compressible beam-column elements and the soil as a hysteretic viscoelastic half-space. A recently developed Green function corresponding to the dynamic Mindlin problem is implemented in the numerical formulation. Exact analytical solutions for the differential equations for the piles under distributed harmonic excitations are used. Treating the half-space as a three-dimensional elastic continuum, the interaction problem is formulated by satisfying equilibrium and displacement compatibility along the pile-soil interface. Solutions adopted for the seismic waves are obtained by direct integration of the differential equations in terms of amplitudes. Salient features of the seismic response are identified in several non-dimensional plots. Results of the analyses compare favourably with the limited data available in the literature
Semi-leptonic (1968) decays as a scalar meson probe
The unusual multiplet structures associated with the light spin zero mesons
have recently attracted a good deal of theoretical attention. Here we discuss
some aspects associated with the possibility of getting new experimental
information on this topic from semi-leptonic decays of heavy charged mesons
into an isosinglet scalar or pseudoscalar plus leptons.Comment: 11 pages, 4 figure
Mini-stop bands in single heterojunction photonic crystal waveguides
Spectral characteristics of mini-stop bands (MSB) in line-defect photonic crystal (PhC) waveguides and in heterostructure PhC waveguides having one abrupt interface are investigated. Tunability of the MSB position by air-fill factor heterostructure PhC waveguides is utilized to demonstrate different filter functions, at optical communication wavelengths, ranging from resonance-like to wide band pass filters with high transmission. The narrowest filter realized has a resonance-like transmission peak with a full width at half maximum of 3.4 nm. These devices could be attractive for coarse wavelength selection (pass and drop) and for sensing applications.Support from the Swedish Research Council (VR) is gratefully acknowledged
Novel heuristic for low-batch manufacturing process scheduling optimisation with reference to process engineering
YesScheduling is an important element that has a major impact on the efficiency of all
manufacturing processes. It plays an important role in optimising the manufacturing times and
costs resulting in energy efficient processes. It has been estimated that more than 75% of
manufacturing processes occur in small batches. In such environments, processes must be able to
perform a variety of operations on a mix of different batches. Batch-job scheduling optimisation is
the response to such low batch manufacturing problems. The optimisation of batch-job process
scheduling problem is still a challenge to researchers and is far from being completely solved due
to its combinatorial nature. In this paper, a novel hybrid heuristic (HybH) solution approach for
batch-job scheduling problem is presented with the objective of optimising the overall Makespan
(Cmax). The proposed HybH is the combination of Index Based Heuristic (IBH) and the Finished
Batch-Job (FBJ) process schedule. The heuristic assigns the first operation to a batch-job using
IBH and the remaining operations on the basis FBJ process schedule. The FBJ process schedule
gives priority to the batch-job with early finished operations, without violating the constraints of
process order. The proposed HybH is explained with the help of a detailed example. Several
benchmark problems are solved from the literature to check the validity and effectiveness of the
proposed heuristic. The presented HybH has achieved batch-job process schedules which have
outperformed the traditional heuristics. The results are encouraging and show that the proposed
heuristic is a valid methodology for batch process scheduling optimisation
Promoter Hypermethylation of Tumor suppressor Genes correlates with Tumor grade and Invasiveness in patients with Urothelial Bladder Cancer
Purpose: To investigate the promoter methylation status at selected loci which encode for key proteins involved in apoptosis, DNA repair, cell cycle control and progression in urothelial cell carcinoma of bladder and compare the findings from tissue samples with that of plasma.
Methods: Total genomic DNA was isolated from 43 non-muscle invasive (low grade) and 33 muscle invasive (high grade) urothelial bladder cancer samples along with 10 control cases of normal bladder mucosa. Promoter methylation status was investigated for RASSF1A, APC, MGMT, CDKN2A and CDKN2B genes using real-time methylation-specific PCR with SYBR® green. Plasma samples from 16 patients with muscle invasive high grade bladder cancer were also subjected to similar analyses.
Results: Promoter hypermethylation was frequently observed in RASSF1A, APC and MGMT gene promoters (p-value \u3c 0.001). The methylation was more prominent in the muscle invasive high grade bladder cancer when compared to non-muscle invasive low grade group (p-value \u3c 0.001) and normal bladder mucosa (p-value \u3c 0.05). The RNA expression of RASSF1A, APC and MGMT was also found to be decreased in the muscle-invasive high grade bladder cancer when compared to the non muscle invasive low grade group (p-value \u3c 0.05). RASSF1A, MGMT and CDKN2A showed comparable results when data from 16 plasma samples was compared to the corresponding tissue samples.
Conclusion: Our results suggest that epigenetic silencing of RASSF1A, APC and MGMT genes is strongly associated with invasive high grade urothelial bladder cancer. Thus, status of promoter methylation has the potential to serve as valuable tool for assessing aggressiveness of urothelial cell carcinoma of bladder
Chemical kinetics of silver diammine fluoride in demineralization and remineralization solutions—an in vitro study
Introduction: Silver Diammine Fluoride (SDF) is a clinical minimal intervention to manage dentin caries. Its chemistry in demineralization conditions has been investigated widely, but far less in remineralization conditions. The aim was to investigate and compare the chemical reactions when SDF is added to remineralization and demineralization solutions.
Methods: 0.01 ml SDF (Riva Star) was added to deionized water (DW); demineralization (DS = pH4) and remineralization (RS = pH7.0) solutions. The time sequence of concentrations of NH4+, F−, and Ag+ were measured using ion selective electrodes (ISEs) every 2 min. The pH was also measured. Precipitates were characterized using x-ray Diffraction (XRD) and, 31P and 19F nuclear magnetic resonance spectroscopy (NMR).
Results: The concentrations of NH4+ and Ag+ showed decreasing trends in DW (−0.12 and −0.08 mM/h respectively), and in DS (−1.06 and −0.5 mM/h respectively); with corresponding increase in F− concentration (0.04 and 0.7 mM/h respectively). However, in RS, NH4+ concentration showed little change (0.001 mM/h), and Ag+ and F− concentrations were negligible. XRD results showed that precipitates (in RS only) contained AgCl, and metallic Ag. NMR showed that fluorapatite/carbonated fluorapatite (FAP/CFAP) were formed. The pH increased after SDF addition in all three solutions.
Discussion: SDF dissolved to release NH4+, F− and Ag + . In DW and DS, NH4+ combined with Ag+ to form diamminesilver, causing an increase of F− and pH. In RS, F− reacted with Ca2+ and (PO)43− to form FAP/CFAP, and Ag+ reacted with Cl− to form AgCl/Ag. These suggests why SDF is effective in managing dentin caries
Changing characteristics of the water consumption structure in Nanjing city, Southern China
Understanding the changes in water consumption structure in order to take measures for demand control is very important for sustainable water resources management. In this study, using the Southern China area of Nanjing as an example, we employed the information entropy method to analyze the water consumption structure, as well as the grey incidence analysis to analyze synthetic incidence degree of the factors associated with agricultural, industrial, domestic, and ecological water consumption. The results show that the degree of balance among water consumption sectors has increased from 0.755 to 0.825 between 1993 and 2014. Gradual decrease of the relative proportion of a single water user structure in a water consumption system has made the utilization of water resources in Nanjing rational and diversified. The study identifies three stages of transformation of water structure in Nanjing, namely, a growth period from 1993 to 2002, an adjustment period from 2003 to 2010, and another growth period from 2011 to 2014. The synthetic incidence degree analysis indicates that adjustments of the agricultural and industrial water consumption as well as water saving measures are the main factors that affected water consumption structure in Nanjing. It is expected that the results obtained from this study will provide references to optimize the utilization of urban water resources
Are inert glasses really inert?
Abstract
Objectives
The aim of this study was to investigate the degradation of inert glass fillers which are commonly used in conventional resin-based composites to provide radiopacity, reduce the polymerization shrinkage and improve the mechanical properties.
Methods
75 mg of five different glass powders (1 µm) was immersed separately into 50 mL of acetic acid (pH 4) and tris buffer (pH 7.4) for up to 4 weeks. At each time point the glass powder was filtered and dried for characterization using ATR-FTIR and XRD to assess the degradation behavior and crystallization. ICP-OES, ISE and pH measurements were performed on the supernatant solutions to monitor the pH and ion release.
Results
Although FTIR and XRD analysis showed no significant glass degradation or crystallization upon immersion, there was a substantial release of ions from the inert fillers, especially from BABFG and CDL. Barium release for these fillers were 270 and 165 ppm respectively. G018–373 glass presented the lowest ion release followed by GM27884 and BABG. The ion release was more pronounced in acidic conditions compared to neutral conditions apart from the fluoride release.
Significance
Inert glasses are not as inert as previously thought. This may result in leaching of ions, potentially causing toxicity, reduction in mechanical properties, increased wear and subsequent failure of the composite material. The ions released from the inert glass may interfere with other glass fillers such as bioactive glass fillers, inhibiting degradation of the bioactive glass, beneficial ion release from the bioactive glass, pH neutralization and apatite formation
The Serological Findings of Parvo virus B19 and Neopterin Detection among Sickle cell Disease Patients and Blood Doners in the Kingdom of Bahrain
Introduction. Parvovirus B19 (PV B19) is a small, non-enveloped, ss DNA virus with an icosahedral capsid having a size of 18–26 nm. PV B19 transmits through respiratory droplets, blood transfusion and nosocomial infections that have also been documented recently. The virus targets the actively dividing Erythroid Progenitor Cells (EPCs) that are found in the human bone marrow, fetal liver and human umbilical cord. Methods. The study was particularly conducted on Sickle Cell Disease (SCD) patients and focuses on the determination of parvovirus B19 among Bahraini population by relying on their clinical status. The serological study of PV B19 was performed using Enzyme Linked Immunosorbent Assay (ELISA) technique and includes 150 SCD patientsand 100 healthy blood donors in which both males and females were employed. The samples were taken from the emergency unit of Salmania Medical Complex (SMC) and Ibrahim Khalil Kano Center (IKKC). Results. Of the 150 SCD patients, 100 were with vaso-occlusive crisis(VOC) and 50 non-vaso-occlusive crisis (NVOC). The three groups showed significantly higher percentages of PV B19 IgG but the percentage in SCD was relatively high compared to the control group of age-matched healthy donors – 70% of the VOC patients, 76% of the NVOC cases and 57% of blood donors were found to be IgG sero-positive. Discussion and Conclusion. PV B19 is a pathogenic virus and sometimes considered as life-threatening specifically for those individuals who have SCD due to which a risk of transient aplastic crisis increases. This virus is only associated with those patients whohave some hematological disorders such as hemolytic anemia and erythro-cytopenia. An effective screening test must be performed in the future to reduce the risk of PV B19 infection.
Keywords: Aplastic Crisis, Seroprevalence, Bahraini Population, Genotypes, Vasoocclusive crisis, Neopteri
- …