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New insights into the vitamin D requirements during pregnancy

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Bone Research 2017年第3期5卷 161-176页

作者： bruce w Hollis Carol L wagner Department of Pediatrics Darby Children's Research Institute Medical University of South Carolina

Pregnancy represents a dynamic period with physical and physiological changes in both the mother and her developing fetus. The dramatic 2-3 fold increase in the active hormone 1,25（OH）2D concentrations during the early weeks of pregnancy despite minimal increased calcium demands during that time of gestation and which are sustained throughout pregnancy in both the mother and fetus suggests an immunomodulatory role in preventing fetal rejection by the mother. while there have been numerous observational studies that support the premise of vitamin D＇s role in maintaining maternal and fetal well-being, until recently, there have been few randomized clinical trials with vitamin D supplementation. One has to exhibit caution, however, even with RCTs, whose results can be problematic when analyzed on an intent-to-treat basis and when there is high non-adherence to protocol （as if often the case）, thereby diluting the potential good or harm of a given treatment at higher doses. As such, a biomarker of a drug or in this case ＂vitamin＂ or pre-prohormone is better served. For these reasons, the effect of vitamin D therapies using the biomarker circulating 25（OH）D is a far better indicator of true ＂effect.＂ when pregnancy outcomes are analyzed using the biomarker 25（OH）D instead of treatment dose, there are notable differences in maternal and fetal outcomes across diverse racial/ethnic groups, with improved health in those women who attain a circulating 25（OH）D concentration of at least 100 nmol. L-1 （40 ng. mL-1）. Because ,an important issue is the timing or initiation of vitamin D treatment/supplementation, and given the potential effect of vitamin D on placental gene expression and its effects on inflammation within the placenta, it appears crucial to start vitamin D treatment before placentation （and trophoblast invasion）; however, this question remains unanswered. Additional work is needed to decipher the vitamin D requirements of pregnant women and the optimal timing of s

关键词： New insights into the vitamin D requirements during pregnancy

Classification of Soybean Pubescence from Multispectral Aerial Imagery

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Plant Phenomics 2021年第1期3卷 156-166页

作者： Robert w.bruce Istvan Rajcan John Sulik Department of Plant Agriculture University of GuelphGuelphONCanada

The accurate determination of soybean pubescence is essential for plant breeding programs and cultivar ***,soybean pubescence is classified visually,which is a labor-intensive and time-consuming ***,the three classes of phenotypes(tawny,light tawny,and gray)may be difficult to visually distinguish,especially the light tawny class where misclassification with tawny frequently *** objectives of this study were to solve both the throughput and accuracy issues in the plant breeding workflow,develop a set of indices for distinguishing pubescence classes,and test a machine learning(ML)classification approach.A principal component analysis(PCA)on hyperspectral soybean plot data identified clusters related to pubescence classes,while a Jeffries-Matusita distance analysis indicated that all bands were important for pubescence class *** images from 2018,2019,and 2020 were analyzed in this study.A 60-plot test(2019)of genotypes with known pubescence was used as reference data,while whole-field images from 2018,2019,and 2020 were used to examine the broad applicability of the classification *** indices,a red/blue ratio and blue normalized difference vegetation index(blue NDVI),were effective at differentiating tawny and gray pubescence types in high-resolution imagery.A ML approach using a support vector machine(SVM)radial basis function(RBF)classifier was able to differentiate the gray and tawny types(83.1%accuracy and kappa=0:740 on a pixel basis)on images where reference training data was *** tested indices and ML model did not generalize across years to imagery that did not contain the reference training panel,indicating limitations of using aerial imagery for pubescence classification in some environmental ***-throughput classification of gray and tawny pubescence types is possible using aerial imagery,but light tawny soybeans remain difficult to classify and may require training da

关键词： indices spectral consuming

Fracturing,caving propagation and influence of mining on groundwater above longwall panels–a review of predictive models

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International Journal of Mining Science and Technology 2020年第1期30卷 49-54页

作者： bruce Hebblewhite School of Minerals and Energy Resources Engineering University of New South WalesSydney 2052Australia

Historically there have been a number of different hypotheses and empirical models developed in an attempt to describe the nature of fracturing above longwall panels in underground coal *** motivation for suchmodels varies,ranging fromunderstanding the impact ofmining on surface subsidence,to back-analysis of caving behaviour in the immediate roof behind the longwall *** of the most critical motivating factors that is taking on increased importance in many coalfields,is the need for better understanding,and hence prediction of the impact of mining on overlying strata,particularly strata units acting as aquifers for different groundwater *** paper reviews some of the major prediction models in the context of observed behaviour of strata displacement and fracturing above longwall panels in the southern coalfields of New South wales,south of *** paper discusses the parameter often referred to as"height of fracturing"in terms of the critical parameters that influence it,and the relevance and appropriateness of this terminology in the context of overlying sub-surface subsidence and groundwater *** paper proposes an alternative terminology for this parameter that better reflects what it is and how it is *** paper also addresses the potential role of major bedding shear planes mobilised by mining and their potential influence on overlying subsidence and groundwater interference.

关键词： Longwall mining Subsidence Groundwater Caving Underground coal mining

water and nutrient and energy systems in urbanizing watersheds

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Frontiers of Environmental Science & Engineering 2012年第5期6卷 596-611页

作者： Rodrigo VILLARROEL wALKER Michael bruce BECKl, Jim w. HALL warnell School of Forestry & Natural Resources University of Georgia Athens GA 30602-2152 USA Environmental Change Institute University of Oxford Oxford University Centre for the Environment South Parks Road Oxford OXI 3QY UK

Driven by considerations of sustainability, it has become increasingly difficult over the past 15-20 years -- at least intellectually -- to separate out the water infrastructure and water metabolism of cities from their intimately inter-related nutrient and energy metabolisms. Much of the focus of this difficulty settles on the wastewater component of the city＇s water infrastructure and its associated fluxes of nutrients （N, P, C, and so on）. Indeed, notwithstanding the massive volumes of these materials flowing into and out of the city, the notion of an urban nutrient infrastructure is conspicuous by its absence. Likewise, we do not tend to discuss, or conduct research into, ＂soilshed＂ agencies, or soilshed management, or Integrated Nutrient Resources Management （as opposed to its most familiar companion, Integrated water Resources Management, or IwRM）. The paper summarizes some of the benefits （and challenges） deriving from adopting this broader, multi-sectoral ＂systems＂ perspective on addres- sing water-nutrient-energy systems in city-watershed settings. Such a perspective resonates with the growing interest in broader policy circles in what is called the ＂water-food-energy security nexus＂. The benefits and challenges of our Multi-sectoral Systems Analysis （MSA） are illustrated through computational results from two primary case studies： Atlanta, Georgia, USA; and London, UK. Since our work is part of the International Network on Cities as Forces for Good in the Environment （CFG; see ***）, in which other case studies are currently being initiated -- for example, on Kath- mandu, Nepal we close by reflecting upon these issues of water-nutrient-energy systems in three urban settings with quite different styles and speeds of development.

关键词： cities climate change energy sector nutrientsector systems analysis resource recovery water-food-energy security

Temporal evolution of scour at bridge abutments in compound channels

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International Journal of Sediment Research 2022年第5期37卷 662-674页

作者： Yifan Yang bruce w.Melville Xiaozhou Xiong Lu wang School of Engineering The University of Waikato Risland New Zealand Department of Civil and Environmental Engineering The University of Auckland State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and Hydropower Sichuan University

Bridge abutment-induced sediment scour in compound river channels is time-sensitive during floods, and, thus, estimating the scour rate has significance in design. In the current study, large-scale laboratory experiments were done to examine the influence of multiple factors on scour evolution,including channel geometry, bed mobility(clear-water or live-bed), and lateral(embankment intrusion) and vertical(deck submergence) flow contractions. A new method is applied for scour measurement and determination of characteristic scour trends. Results show that the nondimensional time scale is related to flow intensity and may peak before reaching the clear-water scour threshold; the corresponding equations also are derived. It is found that the use of scour countermeasures has a significant impact on the scour rate, and the existing equations for unprotected abutments have limitations. Under clear-water conditions, the scour rate is closely related to the overall flow contraction, which can be better reflected by the ratio of the approaching unit discharge to that at the bridge section. Specifically, the effect of vertical flow contraction on scour rate is more dominant than other factors. Two scour rate curves are derived to suit different structural and flow contraction types for clear-water scour. In contrast, the live-bed scour rate data are generally consistent and fall in a narrow band, showing less dependence on other factors. Finally, a new design approach is established to estimate the time scale and scour rate using the new equations proposed in this paper.

关键词： Abutment scour Temporal evolution Compound channel Time scale Scour rate

Investigation of role of cartilage surface polymer brush border in lubrication of biological joints

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Friction 2022年第1期10卷 110-127页

作者： JinJing LIAO David w.SMITH Saeed MIRAMINI bruce S.GARDINER Lihai ZHANG Department of Infrastructure Engineering.The University of Melbourne.Victoria 3010 Australia Faculty of Engineering and Mathematical Sciences The University of Western AustraliaWA 6009Australia College of Science Health.Engineering and Education.Murdoch UniversityWA 6150Australia

Although experimental evidence has suggested that the polymer brush border(PBB)on the cartilage surface is important in regulating fluid permeability in the contact gap,the current theoretical understanding of joint lubrication is still *** address this research gap,a multiscale cartilage contact model that includes PBB,in particular its effect on the fluid permeability of the contact gap,is developed in this *** modeling is employed to estimate the permeability of the contact *** permeability is classified into two categories:For a gap size>1μm,the flow resistance is assumed to be dominated by the cartilage roughness;for gap sizew resistance is assumed to be dominated by the surface polymers extending beyond the collagen network of the articular *** gap sizes of less than 1μm,the gap permeability decreases exponentially with increasing aggrecan concentration,whereas the aggrecan concentration varies inversely with the gap ***,the gap permeability is employed in a macroscale cartilage contact model,in which both the contact gap space and articular cartilage are modeled as two interacting poroelastic *** fluid exchange between these two media is achieved by imposing pressure and normal flux continuity boundary *** model results suggest that PBB can substantially enhance cartilage lubrication by increasing the gap fluid load support(e.g.,by 26 times after a 20-min indentation compared with the test model without a PBB).Additionally,the fluid flow resistance of PBB sustains the cartilage interstitial fluid pressure for a relatively long period,and hence reduces the vertical deformation of the ***,it can be inferred that a reduction in the PBB thickness impairs cartilage lubrication ability.

关键词： assumed polymer hence

The pitch-catch nonlinear ultrasonic imaging techniques for structural health monitoring

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Science China(Technological Sciences) 2021年第12期64卷 2608-2617页

作者： CHENG Jingwei DRINKwATER bruce w. CHEN XueDong FAN ZhiChao CHEN wei wANG Zhe National Safety Engineering Technology Research Centre for Pressure Vessels and Pipelines Hefei General Machinery Research Institute Co.Ltd.Hefei 230031China Department of Mechanical Engineering University of BristolBristol BS81TRUnited Kingdom

Nonlinear ultrasonic imaging techniques in pulse-echo configuration have recently shown their potential to allow the effective separation of nonlinear and linear features in a nonlinear *** this study,two ultrasonic phased arrays are implemented to produce an image of elastic nonlinearity through the parallel-sequential subtraction of the coherently scattered components in the through-transmission acoustic field at the transmission or subharmonic *** parallel mode,a physical focus at each pixel is achieved by firing the transmitters with a predefined delay *** sequential mode,each transmitter is fired in sequence and all the receivers are employed to capture the data *** full matrix captured data can be post-processed and focused synthetically at the target *** images of parallel focusing and sequential focusing are expected to be linearly identical and hence any differences remained on the subtracted image can be related to the nonlinearities arising from the ***,the imaging metric here is defined as the difference between parallel and sequentially focused amplitudes obtained from forward coherently scattered fields at each target ***,the negative influences due to the instrumentation nonlinearities are investigated by studying the remaining relative phase and amplitude at undamaged pixels.A compensation method is implemented to suppress these noises,significantly enhancing the selectivity of nonlinear scattering *** proposed techniques are then implemented to monitor fatigue crack growth in order to explore the capability of these methods as measures of elastic nonlinearity induced by different sizes of small closed *** promising results suggest that nonlinear imaging can be used to monitor crack growth and improve the detectability at early stages.

关键词： pitch-catch coherent measurement nonlinear imaging fatigue crack monitoring ultrasonic phased array nonlinearities decoupling

Near-bed hydrodynamics associated with the entrainment of coarse particles at different protrusion heights

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Journal of Hydrodynamics 2022年第6期34卷 1067-1080页

作者： Yushu Xie bruce w.Melville Asaad Y.Shamseldin Colin N.whittaker Yifan Yang Department of Civil and Environmental Engineering The University of AucklandAucklandNew Zealand School of Engineering The University of WaikatoHamiltonNew Zealand

This paper presents an investigation of near-bed hydrodynamics for a protruding coarse particle over a regular roughened *** laboratory experiments were undertaken at the threshold flow condition,which induced dislodgement of the protruding *** different protrusion heights,the experimental results show that the protruding particle substantially changed the spatial distributions of time-averaged velocities,turbulent kinetic energy,and Reynolds shear stress when compared with those obtained from a flat rough *** spatial distribution pattern of the flow characteristics shows a reasonable degree of similarity at different protrusion heights examined in this *** the target particle,a zone of low Reynolds shear stress was *** analysis was conducted along the main flow direction,at an elevation close to the top of the target particle.A prevalence of sweep(Quadrant 4)and outwards interaction(Quadrant 1)events were associated with the dislodgement of the protruding *** findings imply that the drag force related to strong streamwise velocities may play a more significant role in protruding particle entrainment than the shear stress.

关键词： Entrainment particle protrusion flow structure shear stress quadrant analysis

Study of Electron Beam Surfi-sculpt during Composite Materials Joining

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稀有金属材料与工程 2011年第S4期40卷 292-296页

作者： bruce Dance The welding Institute(TwI) Cambridge CB1 6ALUK

Electron beam surfi-sculpt is a new metal surface processing technology,which is widely used in the areas of materials surface treatment,composite materials manufacturing,and so *** this paper,comeld technology,which was an application technology of electron beam surfi-sculpt during composite materials area,was *** tensile experiments results and failure forms of Ti6Al4V/Carbon fibre single step joints were compared with different joining methods,such as slick embedding,adhesive bonding,riveting and *** was found that comeld joint had more advantage of tensile property than other joining *** the same time,tensile process of comeld joint was analyzed with numerical simulation,and key factors of protrusions influenced tensile property were obtained,which was of importance to structure design and joint property improvement.

关键词： electron beam surfi-sculpt comeld joining methods tensile experiments numerical simulation