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result(s) for
"Group effects"
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Effect of Relative Stiffness of Pile and Soil on Pile Group Effect
2023
Pile groups are designed to sustain complex loads in various engineering. During the design of a pile group, the obvious pile group effect should be considered for closely spaced pile groups. However, the group effect considered by different scholars varies, which makes it hard for engineers to consider the pile group effect for the design of a pile group. In this study, the finite element (FE) method is proposed to advance our understanding of the variations of pile group effects developed by different researchers, based on the concept of soil–pile relative stiffness. The relationship between soil–pile relative stiffness and normalized lateral load–displacement curves and bending moment profile response of the pile group is investigated. The results show that the pile group effect increases with the increase in soil–pile relative stiffness; the pile group effect increases with the decrease in pile spacing, increases with the increase in of number of piles in the group, and is significantly affected by pile group arrangement as well.
Journal Article
Novel Tetrahydro-1,2,4triazolo3,4-aisoquinoline Chalcones Suppress Breast Carcinoma through Cell Cycle Arrests and Apoptosis
by
Mahmoud I. M. Darwish
,
Ahmed M. Moustafa
,
Ahmed I. Yousef
in
Animal experimentation
,
Animals
,
Antineoplastic Agents - chemistry
2023
Chalcones are interesting anticancer drug candidates which have attracted much interest due to their unique structure and their extensive biological activity. Various functional modifications in chalcones have been reported, along with their pharmacological properties. In the current study, novel chalcone derivatives with the chemical base of tetrahydro-[1,2,4]triazolo[3,4-a]isoquinolin-3-yl)-3-arylprop-2-en-1-one were synthesized, and the structure of their molecules was confirmed through NMR spectroscopy. The antitumor activity of these newly synthesized chalcone derivatives was tested on mouse (Luc-4T1) and human (MDA-MB-231) breast cancer cell lines. The antiproliferative effect was evaluated through SRB screening and the MTT assay after 48 h of treatment at different concentrations. Interestingly, among the tested chalcone derivatives, chalcone analogues with a methoxy group were found to have significant anticancer activity and displayed gradient-dependent inhibition against breast cancer cell proliferation. The anticancer properties of these unique analogues were examined further by cytometric analysis of the cell cycle, quantitative PCR, and the caspases-Glo 3/7 assay. Chalcone methoxy derivatives showed the capability of cell cycle arrest and increased Bax/Bcl2 mRNA ratios as well as caspases 3/7 activity. The molecular docking analysis suggests that these chalcone methoxy derivatives may inhibit anti-apoptotic proteins, particularly cIAP1, BCL2, and EGFRK proteins. In conclusion, our findings confirm that chalcone methoxy derivatives could be considered to be potent drug candidates against breast cancer.
Journal Article
Experimental Study of Negative Skin Friction of Pile Group Foundations for Offshore Wind Turbines on Artificial Islands
2024
Constructing offshore wind turbines on artificial islands is considered a viable option, but negative skin friction (NSF) is a significant adverse factor that cannot be ignored. The NSF adversely affects the bearing capacity of pile foundations. Currently, design methods for studying the impact of NSF group effects mainly rely on empirical approaches. Moreover, existing experimental studies do not simulate the NSF experienced by offshore wind turbine pile groups on artificial islands. In order to further explore the impact of pile group effects on NSF experienced by offshore wind turbine pile foundations on artificial islands, this study conducted indoor model tests on single piles and 3 × 3 rectangular pile groups in sandy soil under uniformly distributed loading on surrounding soil. The experiment measured the settlement of piles at various positions within single piles and rectangular pile groups, as well as the settlement of the soil surrounding the piles and the NSF. Through calculations, the experiment determined the neutral points and NSF group effect coefficients for each pile. The results indicate that densely spaced pile groups are advantageous in reducing settlement of the surrounding soil, thereby mitigating the adverse effects of NSF. Due to the influence of pile group effects, different positions within the group experience varying degrees of NSF. Consequently, in practical engineering applications, settlement of both the pile groups and the surrounding soil should be calculated separately. Furthermore, design considerations for the uplift forces and neutral points of piles at different positions within the pile group should adhere to distinct standards.
Journal Article
Evaluation on influences of inertial mass on seismic responses and structure-soil interactions of pile-soil-piers
2021
This research is to assess the influences of the inertial mass from the girder on the dynamic characteristic, dynamic response, and structure-soil interaction of a pile-soil-pier subsystem in a scale-model of a cable-stayed bridge. Therefore, both connection configurations between the pile-soil-pier and girder, including the sliding and fixed connections, were designed to present various inertial mass from the superstructure delivered to the pile-soil-pier. The pile-soil-pier supported by a 3 × 3 pile-group in mixed soil placed in a shear box was tested using shaking tables. The dynamic characteristics, seismic responses, inertial interactions, and pile group effects of the pile-soil-pier between the sliding and fixed connections were analyzed under three input motions with different shaking amplitudes. These results showed that more inertial mass from the girder significantly increased the reinforcement strain and bending moment at the column bottom and pile top, displacement at the column top, inertial interaction effects, and pile group effects of the pile-soil-pier due to the sliding connection changing to the fixed connection. The inertial mass increment from the girder noticeably decreased the peak accelerations of the column of the pile-soil-pier when subjected to three input motions with different amplitudes. However, the inertial mass insignificantly affected the accelerations of the pile and free-soil. Therefore, the corresponding kinematic interaction effects were almost unaffected by the inertial mass. Additionally, the evident pile group effects were observed in the sliding and fixed connections between the pile-soil-pier and girder. The numerical model could approximately reproduce the macroscopic seismic responses of the pile-soil-piers with sliding and fixed connections and capture the typical response variations induced by the connection configuration change.
Journal Article
Group-size-mediated habitat selection and group fusion-fission dynamics of bison under predation risk
2009
For gregarious animals the cost-benefit trade-offs that drive habitat selection may vary dynamically with group size, which plays an important role in foraging and predator avoidance strategies. We examined how habitat selection by bison (Bison bison) varied as a function of group size and interpreted these patterns by testing whether habitat selection was more strongly driven by the competing demands of forage intake vs. predator avoidance behavior. We developed an analytical framework that integrated group size into resource selection functions (RSFs). These group-size-dependent RSFs were based on a matched case-control design and were estimated using conditional logistic regression (mixed and population-averaged models). Fitting RSF models to bison revealed that bison groups responded to multiple aspects of landscape heterogeneity and that selection varied seasonally and as a function of group size. For example, roads were selected in summer, but not in winter. Bison groups avoided areas of high snow water equivalent in winter. They selected areas composed of a large proportion of meadow area within a 700-m radius, and within those areas, bison selected meadows. Importantly, the strength of selection for meadows varied as a function of group size, with stronger selection being observed in larger groups. Hence the bison-habitat relationship depended in part on the dynamics of group formation and division. Group formation was most likely in meadows. In contrast, risk of group fission increased when bison moved into the forest and was higher during the time of day when movements are generally longer and more variable among individuals. We also found that stronger selection for meadows by large rather than small bison groups was caused by longer residence time in individual meadows by larger groups and that departure from meadows appears unlikely to result from a depression in food intake rate. These group-size-dependent patterns were consistent with the hypothesis that avoidance of predation risk is the strongest driver of habitat selection.
Journal Article
Ultimate Lateral Bearing Capacity and Group Effect of Belled Wedge Pile Groups
by
Meng, Yongdong
,
Kong, Gangqiang
,
Peng, Huaifeng
in
Bearing capacity
,
Civil Engineering
,
Comparative analysis
2019
Pile foundation of ports, high-voltage transmission line tower are subjected to amount of lateral loading, prediction on lateral bearing capacity is one of the most important projects in structure design. This paper pertains to the model tests on pile-soil interaction of single pile, 2 × 1 and 2 × 2 belled wedge pile groups embedded in sand under lateral load. The load versus displacement, and the soil pressures along depth surrounding piles are measured, the ultimate lateral bearing capacities and group effects of belled wedge piles are analyzed and discussed. An simplified theoretical calculation method on predicting the lateral bearing capacities of shaped pile groups with considering group pile
p-y
curves, and longitudinal cross-section variation are proposed. The accuracy and reliability of this developed calculation method are verified through the comparative analysis with model test results obtained in this study and previous literature. The predicted values of lateral bearing capacities have suitable agreement with the measured data. It also shows that the ultimate lateral bearing capacities of belled wedge pile group are nearly 1.8–2.0 times of those of traditional belled pile with the same concrete usage in this study’s condition.
Journal Article
Removal of Trithiocarbonyl End Group of RAFT-Polymerized Poly(stearyl acrylate) and Effect of the End Group on Thermal and Structural Properties
by
Takahashi, Tatsuhiro
,
Takamura, Masumi
,
Oishi, Eri
in
Addition polymerization
,
Azobisisobutyronitrile
,
Calibration
2021
The effect of a long alkyl end group on the thermal and structural properties of RAFT (reversible addition-fragmentation chain transfer)-polymerized poly(stearyl acrylate) (PSA) was investigated. RAFT-polymerized PSA was prepared using 2-cyano-2-[(dodecylsulfanylthiocarbonyl) sulfanyl] propane (CDTP) with long alkyl group as a chain transfer agent and azobisisobutyronitrile (AIBN) as an initiator. The RAFT polymerization resulted in the polymerized structure having trithiocarbonyl (TTC) at one end and isobutyronitrile at the other end. RAFT-polymerized PSA was prepared with two different molecular weights. The TTC end group was replaced by isobutyronitrile using radical reaction with AIBN through optimization of the conditions, which resulted in isobutyronitrile at both ends. The effect of the end group on the thermal and structural properties was investigated using differential scanning calorimetry and X-ray diffraction, and the results indicated that the long alkyl group from TTC lowers the melting point and semi-crystalline structure in the case of low molecular weight PSA.
Journal Article
No effects of low and high consumption of dairy products and calcium supplements on body composition and serum lipids in Puerto Rican obese adults
by
Ríos, Ruth E.
,
Bertrán, José J.
,
Soltero, Sandra
in
Adipose Tissue
,
Adipose Tissue - metabolism
,
administration & dosage
2011
Epidemiologic studies have shown that a high calcium intake is related to lower body weight, fat, and serum lipids in obese individuals. However, clinical studies have shown inconclusive results. The present study was conducted to determine if dairy or calcium supplementation alters body composition or serum lipids in Puerto Rican obese adults without dietary energy restriction or exercise.
A 21-wk randomized clinical trial was conducted in 30 obese adults, aged 21–50 y, with usual calcium intakes <700 mg/d. Subjects were randomly assigned to the following: high dairy (∼1300 mg/d of calcium from dairy products by substituting foods); high calcium (∼1300 mg/d of calcium; ∼700 mg/d from diet and 600 mg/d from a supplement); or placebo. Subjects were asked to continue their established dietary intake (except for the high dairy group) and their physical activity during the study. Body weight was measured monthly; body fat, bone, and serum lipids (total cholesterol, high-density lipoprotein, low-density lipoprotein, and triacylglycerol) were measured at baseline and at 21 wk. Pairwise differences in study endpoints among the groups were assessed using ANOVA and post-hoc analysis.
Grand mean calcium intake was 1200 ± 370 (median 1187) mg/d in the high dairy group, 1171 ± 265 (median 1165) mg/d in the high calcium group, and 668 ± 273 (median 691) mg/d in the control group, which was significantly lower compared to the two treatment groups (
P < 0.001). There were no significant group effects in any of the outcome variables.
A high dairy or calcium diet alone did not alter body composition or serum lipids profile in a sample of Puerto Rican obese adults.
Journal Article
What drives national support for multilateral climate finance? International and domestic influences on Australia’s shifting stance
2017
The fulfilment of wealthy countries’ commitment to mobilise $100 billion a year in climate finance by 2020 will hinge on maintaining domestic political support in contributor countries. Predictability in flows of climate finance is likely to enhance the overall stability of the climate finance system and the broader climate regime. However, at present it remains unclear how the 2020 target will be achieved and little is known about what drives fluctuations in support among contributor countries. This article explores domestic and international factors that may explain fluctuations in national support through a case study of Australia’s climate finance from 2007 to 2015. Drawing on documentary analysis and interviews with officials and stakeholders, the paper tracks two domestic factors that may influence support for climate finance—the government’s political orientation and public concern about climate change—and two international factors—commitment to multilateral agreements and international peer pressure. While some accounts view climate policy choices as being driven primarily by domestic factors, we find that the government’s political orientation on domestic climate policy and aid explains some but not all variations in Australia’s stance on climate finance. International peer group effects have moderated the positions of two governments that were otherwise reluctant to act on climate change. National policy reforms combined with improved multilateral oversight and more established replenishment cycles could bolster support in contributor countries and thereby strengthen the capacity of the climate finance system.
Journal Article
A Systematic Experimental Study on the Group Effect of Dragloads in Pile Foundations
by
Pang, Xiaochao
,
Su, Dong
,
Gao, Zhiyao
in
Civil Engineering
,
Compressibility
,
Compressibility effects
2020
There is a paucity of systematic experimental studies on the group effect of dragloads in pile foundations. This paper reports on a series of 1-g model tests that were conducted on single piles as well as 2 × 2 and 3 × 3 pile groups with various pile spacings to investigate the influence of soil compressibility, pile installation method, pile end constraint, and pile spacing on dragload development in the piles. The results indicate that soil compressibility significantly influences the magnitude of dragloads developed in single piles and piles in a group. However, the effect of soil compressibility on the group effect (a measure of dragload reduction) is negligible. Pile spacing is the most significant factor that influences group effect, followed by the number and position of piles. The group effect can reach 50% for a spacing of 3D (where D denotes pile diameter), but becomes negligible for a spacing of 7D. The influence of pile end constraint and pile installation method on group effect is comparatively insignificant. Although group effects of the suspending piles are marginally lower than those of end-bearing piles under otherwise identical conditions, the dragloads on the suspending piles correspond to tensile forces and are detrimental to concrete piles.
Journal Article