Wall slope effects on the vertical pull-out capacity of tapered suction caissons

AbstractSuction caissons offer certain advantages over other underwater foundation systems by virtue of large bearing capacity, ease of installation, and efficiency. They are typically built with upright walls. The behaviour of upright suction caissons in regard to their applications, installation, load-bearing, etc. has already been investigated by a number of researchers. However, the performance of tapered suction caissons has not been formerly studied. This paper addresses the pull-out capacity of tapered suction caissons under vertical pull-out loads. A numerical approach was used. The finite element model was first calibrated against available test results on upright suction caissons and then used to simulate the pull-out of tapered caissons. It is admitted, however, that further validation of the model against experimental results on tapered suction caissons will increase the acceptability of the results. It was observed that positive wall slopes may noticeably improve the pull-out capacity. A change from local to global failure modes was postulated as the main reason for this improved resistance. With negative wall slopes, however, the pull-out capacity slightly decreased. In addition, effects from the caisson wall slope were investigated for a number of caisson geometries, drainage conditions and soil properties

Improved Reliability Determination When Testing Cold-formed Steel Components

The objectives of this paper are to (a) determine the sensitivity of the reliability calculations in Chapter F of the AISI Specification (AISI-S100-07) to controlling load combinations and loading ratios, and (b) develop a more robust alternative for the use of Chapter F. To complete this study the bias factors and variances for all loading conditions are established. In addition, a range of practical load ratios is agreed upon. Parametric studies are performed to explore load case and load ratio dependency for use in the determination of the resistance factor, Φ; specifically, the pre-factor term CΦ and the load variance term VQ. The parametric studies are simplified into a table that provides load case dependent CΦ and VQ factors. The table is recommended for use in Chapter F reliability analysis of new products

Optimization and One-Step Purification of Recombinant V Antigen Production from Yersinia pestis

The purpose of this study was to develop an efficient and inexpensive method for the useful production of recombinant protein V antigen, an important virulence factor for Yersinia pestis. To this end, the synthetic gene encoding the V antigen was subcloned into the downstream of the intein (INT) and chitin-binding domain (CBD) from the pTXB1 vector using specific primers. In the following, the produced new plasmid, pTX-V, was transformed into E. coli ER2566 strain, and the expression accuracy was confirmed using electrophoresis and Western blotting. In addition, the effects of medium, inducer, and temperature on the enhancement of protein production were studied using the Taguchi method. Finally, the V antigen was purified by a chitin affinity column using INT and CBD tag. The expression was induced by 0.05 mM IPTG at 25 °C under optimal conditions including TB medium. It was observed that the expression of the V-INT�CBD fusion protein was successfully increased to more than 40 of the total protein. The purity of V antigen was as high as 90. This result indicates that V antigen can be produced at low cost and subjected to one-step purification using a self-cleaving INT tag. © 2020, Springer Science+Business Media, LLC, part of Springer Nature

Celecoxib as an Adjuvant to Fluvoxamine in Moderate to Severe Obsessive-compulsive Disorder: A Double-blind, Placebo-controlled, Randomized Trial

Introduction: A growing body of evidence implicates inflammatory cascades in the pathophysiology of obsessive-compulsive disorder (OCD), making this pathway a target for development of novel treatments. Methods: 50 outpatients with moderate to severe OCD participated in the trial, and underwent 10 weeks of treatment with either celecoxib (200 mg twice daily) or placebo as an adjuvant to fluvoxamine. Participants were investigated using Yale-Brown Obsessive Compulsive Scale (Y-BOCS). The main outcome measure was to assess the efficacy of celecoxib in improving the OCD symptoms. Results: General linear model repeated measures demonstrated significant effect for time � treatment interaction on the Y-BOCS total scores F (1.38, 66.34)=6.91, p=0.005. Kaplan-Meier estimation with log-rank test demonstrated significantly more rapid response in the celecoxib group than the placebo group (p<0.001). There was no significant difference in adverse event frequencies between the groups. Discussion: The results of the current study suggest that celecoxib could be a tolerable and effective adjunctive treatment for more rapid and more satisfying improvements in OCD symptoms. © Georg Thieme Verlag KG Stuttgart, New York

Towards the Design of Cold-formed Steel Foam Sandwich Columns

In this paper a design method for the compressive capacity of sandwich panels comprised of steel face sheets and foamed steel cores is derived and verified. Foamed steel, literally steel with internal voids, provides the potential to mitigate many local stability issues through increasing the effective width-to thickness of the component for the same amount of material. Winter’s classical effective width expression was generalized to the case of steel foam sandwich panels. The provided analytical expressions are verified with finite element simulations employing brick elements that explicitly model the steel face sheets and steel foam cores. The closed-form design expressions are employed to conduct parametric studies of steel foam sandwich panels with various face sheet and steel foamed core configurations. The studies show the significant strength improvements possible with steel foam sandwich panels when compared with plain steel sheet/plate

Preparation and Evaluation of Rivax Protein Loading in Chitosan Nanoparticles

BACKGROUND AND OBJECTIVE: Ricin toxin is a heterodimer glycoprotein which, due to its high toxicity, is used as a bioterrorism agent. Immunogenicity studies against ricin are now focused on two subunit vaccine candidates, including RiVax and RVEc. These studies have examined the vaccine candidate immunization as an alone and in combination with adjuvant, however, there is not a published study on the immunogenicity evaluation of the candidate vaccine through the delivery by nanoparticles. The aim of this study was preparation and evaluation of RiVax recombinant vaccine-loading in chitosan nanoparticles. METHODS: In this experimental study, After transferring the RiVax gene to the bacterium, inducing the expression and purification of the RiVax protein by affinity chromatography column, the RiVax protein was loaded with Ionic Gelation method in chitosan nanoparticles. Then, the properties of nanoparticles including size, morphology, loading percentage and release pattern of RiVax protein from nanoparticles and stability of this protein during acidic loading conditions in nanoparticles by SDS-PAGE were evaluated. Also, Immunization study were performed on 3 mouse groups (n=4/group) by RiVax protein, Nanoparticles containing protein and phosphate buffer. FINDING: The results of this study showed that the nanoparticles containing protein had a size of 178 nm and a Zeta potential of +27.8 MV and a polydispersity index of 0.193. Also, according to SDS-PAGE results, it was found that the RiVax recombinant protein was denatured during the process of preparing the chitosan nanoparticles. CONCLUSION: The results of this study showed that the RiVax protein has been unstable in acidic conditions for the production of chitosan nanoparticles and Ionic Gelation method is not suitable for loading this protein in chitosan nanoparticles

Minocycline combination therapy with fluvoxamine in moderate-to-severe obsessive�compulsive disorder: A placebo-controlled, double-blind, randomized trial

Aim: Several lines of evidence implicate glutamatergic dysfunction in the pathophysiology of obsessive�compulsive disorder (OCD), presenting this neurotransmitter as a target for the development of novel pharmacotherapy. The objective of this study was to assess the efficacy of minocycline as an augmentative agent to fluvoxamine in the treatment of patients with OCD. Methods: One hundred and two patients with the diagnosis of moderate-to-severe OCD were recruited to this study. A randomized double-blind trial was designed and patients received either L-carnosine or placebo as adjuvant to fluvoxamine for 10 weeks. The patients randomly received either minocycline 100 mg twice per day or placebo for 10 weeks. All patients received fluvoxamine (100 mg/day) for the first 4 weeks, followed by 200 mg/day for the rest of the trial, regardless of their treatment groups. Participants were evaluated using the Yale�Brown Obsessive Compulsive Scale (Y-BOCS). The main outcome measure was to assess the efficacy of minocycline in improving the OCD symptoms. Results: General linear model repeated measures demonstrated significant effect for time � treatment interaction on the Y-BOCS total scores, F(1.49, 137.93) = 7.1, P = 0.003, and Y-BOCS Obsession subscale score, F(1.54, 141.94) = 9.72, P = 0.001, and near significant effect for the Y-BOCS Compulsion subscale score, F(1.27, 117.47) = 2.92, P = 0.08. A significantly greater rate of partial and complete response was observed in the minocycline group (P < 0.001). The frequency of side-effects was not significantly different between the treatment arms. Conclusion: The results of this study suggest that minocycline could be a tolerable and effective adjuvant in the management of patients with OCD. © 2016 The Authors. Psychiatry and Clinical Neurosciences © 2016 Japanese Society of Psychiatry and Neurolog

Dynamic behaviour of offshore structure members subjected to ship collision

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