The EC3 approach to the design of columns, beams and beam-columns

L. Gardner,D. A. Nethercot 국제구조공학회 2005 Steel and Composite Structures, An International J Vol.5 No.2

Procedures given in Eurocode 3 Part 1.1 (EN 1993-1-1) for design of the main types of structural member under given systems of loading are presented and described. Whereas some of these e.g. the procedure for axially loaded columns, are little changed from the early concept that appeared more than 25 years ago in the European Recommendations and have subsequently been adopted in many other steel codes of the world, others such as the interaction formulae for beam-columns are new, with aspects of the provisions still under development. For each type of member the basis of the procedure is described and some comparative comments made.

Addition of interleukin-6 to mouse embryo culture increases blastocyst cell number and influences the inner cell mass to trophectoderm ratio

Kelley, Rebecca L,Gardner, David K The Korean Society for Reproductive Medicine 2017 Clinical and Experimental Reproductive Medicine Vol.44 No.3

Objective: In vitro culture of preimplantation embryos is improved by grouping embryos together in a drop of media. Individually cultured embryos are deprived of paracrine factors; with this in mind, we investigated whether the addition of a single embryo-secreted factor, interleukin-6 (IL-6), could improve the development of individually cultured embryos. Methods: Mouse embryos were cultured individually in $2{\mu}L$ of G1/G2 media in 5% oxygen and supplemented with a range of doses of recombinant mouse or human IL-6. Results: Mouse IL-6 increased hatching at doses of 0.01 and 10 ng/mL compared to the control (93% and 93% vs. 78%, p< 0.05) and increased the total number of cells at a dose of 0.1 ng/mL compared to the control ($101.95{\pm}3.36$ vs. $91.31{\pm}3.33$, p< 0.05). In contrast, the highest dose of 100 ng/mL reduced the total number of cells ($79.86{\pm}3.29$, p< 0.05). Supplementation with human IL-6 had a different effect, with no change in hatching or total cell numbers, but an increase in the percentage of inner cell mass per embryo at doses of 0.1, 1, and 100 ng/mL compared to the control ($22.9%{\pm}1.1%$, $23.3%{\pm}1.1%$, and $23.1%{\pm}1.1%$ vs. $19.5%{\pm}1.0%$, p< 0.05). Conclusion: These data show that IL-6 improved mouse embryo development when cultured individually in complex media; however, an excess of IL-6 may be detrimental. Additionally, these data indicate that there is some cross-species benefit of human IL-6 for mouse embryos, but possibly through a different mechanism than for mouse IL-6.

Characteristics and survival of ovarian cancer patients treated with neoadjuvant chemotherapy but not undergoing interval debulking surgery

Ying L. Liu,Olga T. Filippova,Qin Zhou,Alexia Iasonos,Dennis S. Chi,Oliver Zivanovic,Yukio Sonoda,Ginger J. Gardner,Vance A. Broach,Roisin E. OCearbhaill,Jason A. Konner,Carol Aghajanian,Kara Long Roc 대한부인종양학회 2020 Journal of Gynecologic Oncology Vol.31 No.1

Objective: Neoadjuvant chemotherapy (NACT) followed by interval debulking surgery (IDS)confers similar outcomes as primary debulking surgery and chemotherapy. Little is knownabout patients who receive NACT but do not undergo debulking surgery. Our aim was tocharacterize these patients. Methods: We prospectively identified patients with newly diagnosed stage III/IV ovariancancer treated with NACT from 7/1/15–12/1/17. Fisher exact and Wilcoxon rank-sum tests wereused to compare clinical characteristics by surgical status. The Kaplan-Meier method wasused to estimate survival outcomes. Log-rank test and Cox proportional hazards model wereapplied to assess the relationship of covariates to outcome, and time-dependent covariateswere applied to variables collected after diagnosis. Results: Of 224 women who received NACT, 162 (72%) underwent IDS and 62 (28%) didnot undergo surgery. The non-surgical group was older (p<0.001), had higher Charlsoncomorbidity index (CCI; p<0.001), lower albumin levels (p=0.007), lower Karnofskyperformance scores (p<0.001), and were more likely to have dose reductions in NACT(p<0.001). Reasons for no surgery included poor response to NACT (39%), death (15%),comorbidities (24%), patient preference (16%), and loss to follow-up (6%). The nosurgery group had significantly worse overall survival (OS) than the surgery group (hazardratio=3.34; 95% confidence interval=1.66–6.72; p<0.001), after adjustment for age, CCI, anddose reductions. Conclusions: A significant proportion of women treated with NACT do not undergo IDS, andthese women are older, frailer, and have worse OS. More studies are needed to find optimaltherapies to maximize outcomes in this high-risk, elderly population.

Current situation and future prospects for the Australian beef industry - A review

Greenwood, Paul L,Gardner, Graham E,Ferguson, Drewe M Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.7

Beef production extends over almost half of Australia, with about 47,000 cattle producers that contribute about 20% ($A12.7 billion gross value of production) of the total value of farm production in Australia. Australia is one of the world's most efficient producers of cattle and was the world's third largest beef exporter in 2016. The Australian beef industry had 25 million head of cattle in 2016-17, with a national beef breeding herd of 11.5 million head. Australian beef production includes pasture-based cow-calf systems, a backgrounding or grow-out period on pasture, and feedlot or pasture finishing. Feedlot finishing has assumed more importance in recent years to assure the eating quality of beef entering the relatively small Australian domestic market, and to enhance the supply of higher value beef for export markets. Maintenance of Australia's preferred status as a quality assured supplier of high value beef produced under environmentally sustainable systems from 'disease-free' cattle is of highest importance. Stringent livestock and meat quality regulations and quality assurance systems, and productivity growth and efficiency across the supply chain to ensure price competiveness, are crucial for continued export market growth in the face of increasing competition. Major industry issues, that also represent research, development and adoption priorities and opportunities for the Australian beef industry have been captured within exhaustive strategic planning processes by the red meat and beef industries. At the broadest level, these issues include consumer and industry support, market growth and diversification, supply chain efficiency, productivity and profitability, environmental sustainability, and animal health and welfare. This review provides an overview of the Australian beef industry including current market trends and future prospects, and major issues and opportunities for the continued growth, development and profitability of the industry.

Effect of element interaction and material nonlinearityon the ultimate capacity of stainless steel cross-sections

M. Theofanous,L. Gardner 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.12 No.1

The effect of element interaction and material nonlinearity on the ultimate capacity of stainless steel plated cross-sections is investigated in this paper. The focus of the research lies in cross-sections failing by local buckling; member instabilities, distortional buckling and interactions thereof with local buckling are not considered. The cross-sections investigated include rectangular hollow sections (RHS), I sections and parallel flange channels (PFC). Based on previous finite element investigations of structural stainless steel stub columns, parametric studies were conducted and the ultimate capacity of the aforementioned cross-sections with a range of element slendernesses and aspect ratios has been obtained. Various design methods, including the effective width approach, the direct strength method (DSM), the continuous strength method (CSM) and a design method based on regression analysis, which accounts for element interaction, were assessed on the basis of the numerical results, and the relative merits and weaknesses of each design approach have been highlighted. Element interaction has been shown to be significant for slender cross-sections, whilst the behaviour of stocky cross-sections is more strongly influenced by the material strain-hardening characteristics. A modification to the continuous strength method has been proposed to allow for the effect of element interaction, which leads to more reliable ultimate capacity predictions. Comparisons with available test data have also been made to demonstrate the enhanced accuracy of the proposed method and its suitability for the treatment of local buckling in stainless steel cross-sections.

Characterisation and Durability of a Vitrified Wasteform for Simulated Chrompik III Waste

Walling, Sam A.,Gardner, Laura J.,Pang, H.K. Celine,Mann, Colleen,Corkhill, Claire L.,Mikusova, Alexandra,Lichvar, Peter,Hyatt, Neil C. Korean Radioactive Waste Society 2021 방사성폐기물학회지 Vol.19 No.3

Legacy waste from the decommissioned A-1 nuclear power plant in the Slovak Republic is scheduled for immobilisation within a tailored alkali borosilicate glass formulation, as part of ongoing site cleanup. The aqueous durability and characterisation of a simulant glass wasteform for Chrompik III legacy waste, was investigated, including dissolution experiments up to 112 days (90℃, ASTM Type 1 water). The wasteform was an amorphous, light green glassy product, with no observed phase separation or crystalline inclusions. Aqueous leach testing revealed a suitably durable product over the timescale investigated, comparing positively to other simulant nuclear waste glasses and vitreous products tested under similar conditions. Iron and titanium rich precipitates were observed to form at the surface of monolithic samples during leaching, with the formation of an alkali deficient alteration layer behind these at later ages. Overall this glass appears to perform well, and in line with expectations for this chemistry, although longer-term testing would be required to predict overall durability. This work will contribute to developing confidence in the disposability of vitrified Chrompik legacy wastes.

Dysregulation of the EphrinB2−EphB4 ratio in pediatric cerebral arteriovenous malformations is associated with endothelial cell in vitro and functions as a novel noninvasive biomarker in patients

Katie Pricola Fehnel,David L. Penn,Micah Duggins-Warf,Maxwell Gruber,Steven Pineda,Julie Sesen,Alexander Moses-Gardner,Nishali Shah,Jessica Driscoll,David Zurakowski,Darren B. Orbach,Edward R. Smith 생화학분자생물학회 2020 Experimental and molecular medicine Vol.52 No.-

We investigated (1) EphrinB2 and EphB4 receptor expression in cerebral AVMs, (2) the impact of an altered EphrinB2: EphB4 ratio on brain endothelial cell function and (3) potential translational applications of these data. The following parameters were compared between AVM endothelial cells (AVMECs) and human brain microvascular endothelial cells (HBMVECs): quantified EphrinB2 and EphB4 expression, angiogenic potential, and responses to manipulation of the EphrinB2:EphB4 ratio via pharmacologic stimulation/inhibition. To investigate the clinical relevance of these in vitro data, Ephrin expression was assessed in AVM tissue (by immunohistochemistry) and urine (by ELISA) from pediatric patients with AVM (n=30), other cerebrovascular disease (n=14) and control patients (n=29), and the data were subjected to univariate and multivariate statistical analyses. Compared to HBMVECs, AVMECs demonstrated increased invasion (p=0.04) and migration (p=0.08), impaired tube formation (p=0.06) and increased EphrinB2:EphB4 ratios. Altering the EphrinB2:EphB4 ratio (by increasing EphrinB2 or blocking EphB4) in HBMVECs increased invasion (p=0.03 and p<0.05, respectively). EphrinB2 expression was increased in AVM tissue, which correlated with increased urinary EphrinB2 levels in AVM patients. Using the optimal urinary cutoff value (EphrinB2>25.7pg/μg), AVMs were detected with high accuracy (80% vs. controls) and were distinguished from other cerebrovascular disease (75% accuracy). Posttreatment urinary EphrinB2 levels normalized in an index patient. In summary, AVMECs have an EphrinB2:EphB4 ratio that is increased compared to that of normal HBMVECs. Changing this ratio in HBMVECs induces AVMEC-like behavior. EphrinB2 is clinically relevant, and its levels are increased in AVM tissue and patient urine. This work suggests that dysregulation of the EphrinB2:EphB4 signaling cascade and increases in EphrinB2 may play a role in AVM development, with potential utility as a diagnostic and therapeutic target.

POSITIVE SCHEME NUMERICAL SIMULATION OF HIGH MACH NUMBER ASTROPHYSICAL JETS

Youngsoo Ha,Carl L. Gardner 한국산업응용수학회 2008 한국산업응용수학회 학술대회 논문집 Vol.4 No.3

High Mach number astrophysical jets are simulated using a positive scheme, and are compared with WENO-LF simulations. A version of the positive scheme has allowed us to simulate astrophysical jets with radiative cooling up to Mach number 270 with respect to the heavy jet gas, a factor of two times higher than the maximum Mach number attained with the WENO schemes and ten times higher than with CLAWPACK. Such high Mach numbers occur in many settings in astrophysical flows, so it is important to develop a scheme that can simulate at these Mach numbers.

Cross-section classification of elliptical hollow sections

T. M. Chan,L. Gardner 국제구조공학회 2007 Steel and Composite Structures, An International J Vol.7 No.3

Tubular construction is widely used in a range of civil and structural engineering applications. To date, the principal product range has comprised square, rectangular and circular hollow sections. However, hot-rolled structural steel elliptical hollow sections have been recently introduced and offer further choice to engineers and architects. Currently though, a lack of fundamental structural performance data and verified structural design guidance is inhibiting uptake. Of fundamental importance to structural metallic design is the concept of cross-section classification. This paper proposes slenderness parameters and a system of cross-section classification limits for elliptical hollow sections, developed on the basis of laboratory tests and numerical simulations. Four classes of cross-sections, namely Class 1 to 4 have been defined with limiting slenderness values. For the special case of elliptical hollow sections with an aspect ratio of unity, consistency with the slenderness limits for circular hollow sections in Eurocode 3 has been achieved. The proposed system of cross-section classification underpins the development of further design guidance for elliptical hollow sections.

Global Instability of Elliptical Hollow Section Beam-columns under Compression and Biaxial Bending

K. H. Law,L. Gardner 한국강구조학회 2013 International Journal of Steel Structures Vol.13 No.4

The global instability of elliptical hollow section members under combined compression plus biaxial bending is studied inthis paper by means of laboratory testing and numerical simulations. A total of 9 beam-column tests were carried out underdifferent combinations of compression and bending about both principal axes. The material properties of the tested sectionswere determined by means of tensile coupon tests. All tested elliptical hollow sections were EHS 150×75×5, and three nominalmember lengths of 1 m, 2 m and 3 m were considered. Graphs of applied load versus mid-span bending moment, based ontheoretical first and second order elastic considerations and the experimental second order inelastic response, are presented anddescribed. Numerical models were initially validated against the experimental data using measured material and geometricproperties, including imperfections. The models were subsequently employed in parametric studies to assess the influence ofmember slenderness and cross-sectional aspect ratio on the structural response. Finally, based on the experimental andnumerical findings, design rules for hot-finished EHS beam-columns were assessed and statistically verified.