STR-949: DISTURBANCE TO NEARBY SURFACE STRUCTURES CAUSED BY TUNNELING INDUCED GROUND DISPLACEMENTS

Damage to nearby surface structures caused by excavation-induced ground displacements is a major concern during excavation of tunnels in congested urban areas. Hence, developing a reliable numerical model for predicting the possibility of damage to nearby structures is needed. This paper presents the details of a comprehensive 3D finite element model developed to study the induced structural distortions of adjacent structures due tunneling activities. The proposed 3D model used the newly develop shotcrete material model in Plaxis to model the reinforced concrete elements of the tunnel. Utilizing the developed FE model the characteristics of the soil-structure interaction were studied and the criteria for the safety of the structures were accordingly proposed

Novel adaptation of Marston's stress solution for inclined backfilled stope

In underground mining, it is crucial to consider the arching phenomenon, especially for inclined backfilled trenches and mine stopes. That phenomenon decreases the vertical stress of the fill material, so, the in-site stress has already redistributed itself to the hanging- and foot-walls when the stope was excavated. In such cases, the mobilized resistance due to friction between the granular backfill material and the inclined walls can substantially reduce the pressure at the bottom of the stope, which could have a major impact on the stability of the backfill medium and consequently also on economic aspects. Most of researchers used numerical analysis or Lab. tests to predict both of vertical and lateral stresses in inclined stopes. However, there is a need to investigate analytical solution to describe the behaviour of those stresses in inclined stopes. Based on Marston’s formula, this research provides a new approach to predicting vertical stresses at any depth in inclined backfilled stopes. The proposed approach introduces a new parameter, η, to account for the contribution of backfill arching. This parameter specifies the ratio of normal stresses on the hanging wall and foot wall of the inclined backfilled stope. This differs from previous approaches, which assumed that the normal stress on the inclined backfilled stope's hanging wall and foot wall was equal. To validate the proposed approach, results obtained are compared with numerical, analytical, and experimental results from previous research. It is found that if the proposed parameter, η, is modified to 0.2 for the lateral earth pressure coefficient at rest with an angle of inclination of 60° to 80°, good agreement with experimental data is achieved

In vitro propagation and organogenesis of Lilium ‘Prato’

Lilium consists of more than 80 species native to the Northern Hemisphere. It is widely used as cut flowers, flowering potted and garden plants. Since Lilium in vitro production, as an alternative to the conventional vegetative propagation methods is becoming an important way to increase shoot proliferation rates; therefore, the purpose of this study was to establish a protocol for in vitro production of Lilium Asiatic hybrid ‘Prato’ and to compare between two explants for shoot proliferation and organogenesis. Bulb scales and leaf segments as explants of Lilium ‘Prato’ were cultured on Murashige and Skoog (MS) basal medium supplemented with benzyl adenine (BA) at 0.25, 0.5, 1.0 and 2.0 mg/l and naphthalene acetic acid (NAA) at 0.25, 0.5 and 1.0 mg/l. Callus was formed over the bulb scales before shoot organogenesis occurred, while shoot organogenesis occurred directly from the leaf segments without callus formation. It was found that the bulb scales gave higher percent of shoot regeneration than leaf segments when used as explants and was 96.67 and 64.67%, respectively. BA at 0.5 mg/l gave the highest percentage of shoot formation, shoot height and the lowest number of days to proliferation, while BA at 2.0 mg/l caused a delay in shoot organogenesis and reduced shoot height in both explants.Key words: Lilium hybrid, benzyl adenine, naphthalene acetic acid

The effect of long-term consolidation on foundations underpinned by micropiles in soft clay

So far insufficient research has been done on the long-term behavior of micropiles embedded in a clay medium, even though this has a significant influence on the expected total settlement. This paper considers a square foundation placed on a clay bed and tested under vertical loads until the clay reached its bearing capacity. Subsequently, the plate was underpinned with four micropiles, and the load test was repeated. These test data were used to validate the coupled hydraulic-mechanical three-dimensional finite difference model presented in this paper. In the numerical modelling, four different load transfer scenarios were considered to simulate different approaches to adding floors to an existing building. Consolidation periods of zero months, six months, and five years between the application of the load due to the existing building, and the application of loads due to additional storeys were considered. The six-month period represents a short-term, and the five-year period a long-term scenario. Following the first consolidation period and the application of loads representing additional storeys, a second consolidation period was implemented, such that the combined length of the two consolidation periods was five years. In this study, the results showed that the installation of micropiles immediately after the completion of existing floors is most successful in controlling the settlement of additional floors later on

Characterization of Antimicrobial Susceptibility of Bacterial Biofilms on Biological Tissues

abstract: Prosthetic joint infection (PJI) is a devastating complication associated with total joint arthroplasty that results in high cost and patient morbidity. There are approximately 50,000 PJIs per year in the US, imposing a burden of about $5 billion on the healthcare system. PJI is especially difficult to treat because of the presence of bacteria in biofilm, often highly tolerant to antimicrobials. Treatment of PJI requires surgical debridement of infected tissues, and local, sustained delivery of antimicrobials at high concentrations to eradicate residual biofilm bacteria. However, the antimicrobial concentrations required to eradicate biofilm bacteria grown in vivo or on tissue surfaces have not been measured. In this study, an experimental rabbit femur infection model was established by introducing a variety of pathogens representative of those found in PJIs [Staphylococcus Aureus (ATCC 49230, ATCC BAA-1556, ATCC BAA-1680), Staphylococcus Epidermidis (ATCC 35984, ATCC 12228), Enterococcus Faecalis (ATCC 29212), Pseudomonas Aeruginosa (ATCC 27853), Escherichia Coli (ATCC 25922)]. Biofilms of the same pathogens were grown in vitro on biologic surfaces (bone and muscle). The ex vivo and in vitro tissue minimum biofilm eradication concentration (MBEC; the level required to eradicate biofilm bacteria) and minimum inhibitory concentration (MIC; the level required to inhibit planktonic, non-biofilm bacteria) were measured using microbiological susceptibility assays against tobramycin (TOB) and vancomycin (VANC) alone or in 1:1 weight combination of both (TOB+VANC) over three exposure durations (6 hour, 24 hour, 72 hour). MBECs for all treatment combinations (pathogen, antimicrobial used, exposure time, and tissue) were compared against the corresponding MIC values to compare the relative susceptibility increase due to biofilm formation. Our data showed median in vitro MBEC to be 100-1000 times greater than the median MIC demonstrating the administration of local antimicrobial doses at MIC level would not kill the persisting bacteria in biofilm. Also, administering dual agent (TOB+VANC) showed median MBEC values to be comparable or lower than the single agents (TOB or VANC)Dissertation/ThesisMasters Thesis Bioengineering 201

Allelopathic Effects of Water Hyacinth [Eichhornia crassipes]

Eichhornia crassipes (Mart) Solms is an invasive weed known to out-compete native plants and negatively affect microbes including phytoplankton. The spread and population density of E. crassipes will be favored by global warming. The aim here was to identify compounds that underlie the effects on microbes. The entire plant of E. crassipes was collected from El Zomor canal, River Nile (Egypt), washed clean, then air dried. Plant tissue was extracted three times with methanol and fractionated by thin layer chromatography (TLC). The crude methanolic extract and five fractions from TLC (A–E) were tested for antimicrobial (bacteria and fungal) and anti-algal activities (green microalgae and cyanobacteria) using paper disc diffusion bioassay. The crude extract as well as all five TLC fractions exhibited antibacterial activities against both the Gram positive bacteria; Bacillus subtilis and Streptococcus faecalis; and the Gram negative bacteria; Escherichia coli and Staphylococcus aureus. Growth of Aspergillus flavus and Aspergillus niger were not inhibited by either E. crassipes crude extract nor its five fractions. In contrast, Candida albicans (yeast) was inhibited by all. Some antialgal activity of the crude extract and its fractions was manifest against the green microalgae; Chlorella vulgaris and Dictyochloropsis splendida as well as the cyanobacteria; Spirulina platensis and Nostoc piscinale. High antialgal activity was only recorded against Chlorella vulgaris. Identifications of the active antimicrobial and antialgal compounds of the crude extract as well as the five TLC fractions were carried out using gas chromatography combined with mass spectroscopy. The analyses showed the presence of an alkaloid (fraction A) and four phthalate derivatives (Fractions B–E) that exhibited the antimicrobial and antialgal activities

Genome-wide microRNA profiling of plasma from three different animal models identifies biomarkers of temporal lobe epilepsy

Epilepsy diagnosis is complex, requires a team of specialists and relies on in-depth patient and family history, MRI-imaging and EEG monitoring. There is therefore an unmet clinical need for a non-invasive, molecular-based, biomarker to either predict the development of epilepsy or diagnose a patient with epilepsy who may not have had a witnessed seizure. Recent studies have demonstrated a role for microRNAs in the pathogenesis of epilepsy. MicroRNAs are short non-coding RNA molecules which negatively regulate gene expression, exerting profound influence on target pathways and cellular processes. The presence of microRNAs in biofluids, ease of detection, resistance to degradation and functional role in epilepsy render them excellent candidate biomarkers. Here we performed the first multi-model, genome-wide profiling of plasma microRNAs during epileptogenesis and in chronic temporal lobe epilepsy animals. From video-EEG monitored rats and mice we serially sampled blood samples and identified a set of dysregulated microRNAs comprising increased miR-93-5p, miR-142-5p, miR-182-5p, miR-199a-3p and decreased miR-574-3p during one or both phases. Validation studies found miR-93-5p, miR-199a-3p and miR-574-3p were also dysregulated in plasma from patients with intractable temporal lobe epilepsy. Treatment of mice with common anti-epileptic drugs did not alter the expression levels of any of the five miRNAs identified, however administration of an anti-epileptogenic microRNA treatment prevented dysregulation of several of these miRNAs. The miRNAs were detected within the Argonuate2-RISC complex from both neurons and microglia indicating these miRNA biomarker candidates can likely be traced back to specific brain cell types. The current studies identify additional circulating microRNA biomarkers of experimental and human epilepsy which may support diagnosis of temporal lobe epilepsy via a quick, cost-effective rapid molecular-based test

GWAS meta-analysis of over 29,000 people with epilepsy identifies 26 risk loci and subtype-specific genetic architecture

Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants explain between 39.6% and 90% of genetic risk for GGE and its subtypes. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analyses of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current antiseizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment

Genome-wide identification and phenotypic characterization of seizure-associated copy number variations in 741,075 individuals

Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 individuals with seizure disorders, 16,109 individuals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 individuals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of individuals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between individual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice

Simplified Material Model for Concrete Containing High-Content of Tire-Derived Coarse Aggregate under Compression Loading

The flexible properties of the shredded rubber tires give rubberized concrete desirable properties such as lower relative density, and better dampening ability, higher toughness, and improved deformability resulting in an enhanced dynamic performance. Limited work has been done in modeling these effects. In this study, natural coarse aggregates in concrete mixes were replaced by volume by shredded tires up to 100% replacement ratios following 10% increments. Compression tests were conducted to investigate the effects shredded tires on the mechanical properties of concrete. As expected, the results showed a decrease in the compressive strength and the elastic modulus of the concrete as the replacement ratio increase. Due to compatibility, strain at peak values increased and the integrity of the concrete after failure was enhanced. Models describing the effects shredded tires have on the mechanical properties of the concrete were developed and validated against experimental data from various researchers.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author