bluuebunny/crossref_metadata_2025 huggingface dataset:
Transrepression of the estrogen receptor promoter by calcitriol in human breast cancer cells via two negative vitamin D response elements
Authors: Swami Srilatha , Krishnan Aruna V , Peng Lihong , Lundqvist Johan , Feldman David
Published: June 2013

Calcitriol (1,25-dihydroxyvitamin D3), the hormonally active metabolite of vitamin D, exerts its anti-proliferative activity in breast cancer (BCa) cells by multiple mechanisms including the downregulation of the expression of estrogen receptor α (ER). We analyzed an ∼3.5 kb ER promoter sequence and demonstrated the presence of two potential negative vitamin D response elements (nVDREs), a newly identified putative nVDRE upstream at −2488 to −2473 bp (distal nVDRE) and a previously published sequence (proximal nVDRE) at −94 to −70 bp proximal to the P1 start site. Transactivation analysis using ER promoter deletion constructs and heterologous promoter–reporter constructs revealed that both nVDREs functioned to mediate calcitriol transrepression. In the electrophoretic mobility shift assay, the vitamin D receptor (VDR) showed strong binding to both nVDREs in the presence of calcitriol, and the chromatin immunoprecipitation assay demonstrated the recruitment of the VDR to the distal nVDRE site. Mutations in the 5′ hexameric DNA sequence of the distal nVDRE resulted in the loss of calcitriol-mediated transrepression and the inhibition of protein–DNA complex formation, demonstrating the importance of these nucleotides in VDR DNA binding and transrepression. A putative nuclear factor-Y (NFY) binding site, identified within the distal nVDRE, led to the findings that NFY bound to the distal nVDRE site interfered with the binding of the VDR at the site and reduced calcitriol-mediated transrepression. In conclusion, the ER promoter region contains two negative VDREs that act in concert to bind to the VDR and both nVDREs are required for the maximal inhibition of ER expression by calcitriol. The suppression of ER expression and estrogen-mediated signaling by calcitriol in BCa cells suggests that vitamin D may be useful in the treatment of ER+ BCa.
Endurance training improves insulin sensitivity and body composition in prostate cancer patients treated with androgen deprivation therapy
Authors: Hvid Thine , Winding Kamilla , Rinnov Anders , Dejgaard Thomas , Thomsen Carsten , Iversen Peter , Brasso Klaus , Mikines Kari J , van Hall Gerrit , Lindegaard Birgitte , Solomon Thomas P J , Pedersen Bente K
Published: June 2013

Insulin resistance and changes in body composition are side effects of androgen deprivation therapy (ADT) given to prostate cancer patients. The present study investigated whether endurance training improves insulin sensitivity and body composition in ADT-treated prostate cancer patients. Nine men undergoing ADT for prostate cancer and ten healthy men with normal testosterone levels underwent 12 weeks of endurance training. Primary endpoints were insulin sensitivity (euglycemic–hyperinsulinemic clamps with concomitant glucose-tracer infusion) and body composition (dual-energy X-ray absorptiometry and magnetic resonance imaging). The secondary endpoint was systemic inflammation. Statistical analysis was carried out using two-way ANOVA. Endurance training increased VO2max(ml(O2)/min per kg) by 11 and 13% in the patients and controls respectively (P<0.0001). The patients and controls demonstrated an increase in peripheral tissue insulin sensitivity of 14 and 11% respectively (P<0.05), with no effect on hepatic insulin sensitivity (P=0.32). Muscle protein content of GLUT4 (SLC2A4) and total AKT (AKT1) was also increased in response to the training (P<0.05 andP<0.01 respectively). Body weight (P<0.0001) and whole-body fat mass (FM) (P<0.01) were reduced, while lean body mass (P=0.99) was unchanged. Additionally, reductions were observed in abdominal (P<0.01), subcutaneous (P<0.05), and visceral (P<0.01) FM amounts. The concentrations of plasma markers of systemic inflammation were unchanged in response to the training. No group×time interactions were observed, except for thigh intermuscular adipose tissue (IMAT) (P=0.01), reflecting a significant reduction in the amount of IMAT in the controls (P<0.05) not observed in the patients (P=0.64). In response to endurance training, ADT-treated prostate cancer patients exhibited improved insulin sensitivity and body composition to a similar degree as eugonadal men.
Application of a novel cell-permeable peptide-driven protein delivery in mouse blastocysts
Authors: Kwon Sojung , Kwak Areum , Shin Hyejin , Choi Soyoung , Kim Soohyun , Lim Hyunjung Jade
Published: June 2013

Cell-permeable peptides (CPPs) mediate the delivery of macromolecules into cells. However, whether CPPs are usable in mammalian oocytes and embryos for the modulation of protein expression has not been widely investigated. We have previously designed a novel 12-mer CPP from the conserved region of the human papillomavirus L1 capsid protein. In this study, we tested whether this peptide, LDP12, effectively delivers a protein cargo to mouse oocytes and preimplantation embryos. We prepared a LDP12–EGFP fusion protein having LDP12 as an N-terminal tag. This fusion protein readily enters HeLa cells, a cervical cancer cell line. The entry of LDP12–EGFP was partially blocked by amiloride, while cytochalasin D or methyl-β-cyclodextrin slightly increased the uptake. LDP12–EGFP shows efficient transduction in mouse blastocysts, but not in oocytes, two-cell-stage, or morula-stage-preimplantation embryos. LDP12-mediated delivery of EGFP–LC3, a widely used marker of autophagic activation, is successful in HeLa cells and mouse blastocysts, as it enters cells and exhibits a signature punctate pattern. The lipidation of EGFP–LC3 also normally occurs after transduction, suggesting that the transduced protein retains the functional characteristics. Collectively, we show that LDP12-driven protein delivery is a fast and convenient method applicable to mouse blastocysts and reproductive cancer cells.
Size-Controlled Synthesis of MgO Nanoparticles and the Assessment of Their Bactericidal Capacity
Authors: Cedeño-Mattei Yarilyn , Reyes Myrna , Perales-Pérez Oscar , Román Félix R.
Published: June 2013

The present work focuses on the development of a reproducible and cost-effective size-controlled synthesis route for nanoscale MgO and the preliminary assessment of its bactericide capacity as a function of crystal size. Nanoscale MgO was produced through the thermal decomposition of Mg-carbonate hydrate precursor (hydromagnesite) synthesized in aqueous phase. The exclusive formation of the MgO phase, with an average crystallite size between 7 and 13 ± 1 nm, was evidenced by X-Ray Diffraction and HRTEM analyses. Fourier Transform – Infrared spectroscopy confirmed the evolution of the precursor into the desired MgO structure. The bactericidal tests were conducted by measuring the optical density at 600 nm of E. coli in presence of MgO nanoparticles of specific sizes. MgO nanocrystals with average crystallite sizes of 13nm inhibited bacterial growth up to 35% at 500 mg MgO/L. The mechanism of inhibition could be attributed to the formation of superoxide species on the MgO surface.
Synthesis, Characterization and Pseudocapacitive Behaviour of MnOx/CNT Heterostructures
Authors: Tsai Chung-Ying , Mondal Kanchan , Talapatra S.
Published: June 2013

Manganese oxide based nanoparticles were synthesized by sol-gel process. Methanol, ethanol, and propanol were used as alternative solvent during sol-gel process with manganese acetate as precursor for the preparation of pristine manganese oxide. Hybrid MnOx modified by additions of carbon nanotubes was further prepared. Smallest particle size was observed for manganese oxide prepared from propanol, with diameters range from 16 nm to 50nm. XRD results showed that the as prepared manganese oxide based samples at calcination temperature of 300°C and above were composed of Mn2O3 as dominant phase, with Mn3O4 as minor phase. Specific capacitance measured from two electrode systems of manganese oxide prepared from methanol, ethanol, and propanol at scan rate of 10 mV/s were 88.3, 66.0, 104.8 F/g and the result for the hybrid sample was 140.5 F/g. The highest capacitance of the MnOx revealed a specific capacitance of 231.4 F/g when a 1:1 mixture of propanaol and methanol was employed as the solvent for the sol preparation. Results from electrochemical impedance spectroscopy (EIS) also showed superior electrochemical properties of the hybrid sample over pristine manganese oxide samples.
Lightly modified bamboo for structural applications
Authors: Trujillo David Jorge Alexander , Ramage Michael , Chang Wen-Shao
Published: June 2013

Laminated bamboo is becoming an increasingly widespread commodity, even for structural applications, but it does require considerable transformation of the raw material. The aim of this LimesNet mission to Colombia was to observe how bamboo that has undergone minimal transformation may be used for structural applications. Significant achievements have been made in architecture, academic research and structural engineering with bamboo in Colombia. These are discussed. Observations of numerous bamboo structures are also reported. Bamboo is a promising renewable resource with a low environmental impact, and lightly modified bamboo is an exciting and nascent form of using this material that reinforces its sustainability credentials.
Oleic acid–capped CdTe quantum dots and their applications as nano-LED
Authors: Baruah Lalit , Nath Siddhartha S.
Published: June 2013

A simpler and cost-effective approach, in particular, with the use of oleic acid and liquid paraffin has been used to prepare CdTe quantum dots at relatively low temperatures (150–200°C). Compared with the other solvents (capping agents), oleic acid is cheaper, more environment friendly and more stable in air. The as-prepared CdTe quantum dots possess cubic crystallite and exhibit size in the range of 3–11 nm. This new route reduces the material costs and permits to obtain CdTe quantum dots with a narrow emission (fluorescence) spectra ranging from 602 to 617 nm at room temperature. In order to investigate the application of the prepared samples as nano-LED (nano-light-emitting device), electroluminescence spectroscopy is studied and it shows the emission to be almost at the similar wavelength as that of fluorescence. This study infers the possible application of CdTe quantum dots as nano-LED with an emission in the range of 605–620 nm.
Pilot-scale load tests of a combined multilayered geocell and rubber-reinforced foundation
Authors: Moghaddas Tafreshi S.N. , Khalaj O. , Dawson A.R.
Published: June 2013

ABSTRACT: This paper describes the reinforcing effects of multiple layers of geocell in combination with rubber–soil mixture layers in sand, and compares their behaviour with that of the multilayered geocell reinforcement alone, using plate loading at a diameter of 300 mm. The plate load tests were performed in an outdoor test pit, dug in natural ground measuring 2000 × 2000 mm in plan and 700 mm in depth. The geocell used in the tests was non-perforated with pocket size 110 × 110 mm2and height 100 mm, fabricated from continuous polypropylene filaments as a nonwoven geotextile. The optimum embedded depth of the first layer of geocell and the vertical spacing of geocell layers were found to be approximately 0.2 times the footing diameter, and the optimum percentage of rubber replacement was found to be around 8% by weight of the soil mixture. Both bearing capacity increase and settlement reduction were highest when multiple layers of geocell and rubber reinforcement were used. Results show that the reinforcements' efficiency decreased as the number of reinforcement layers increased, particularly at low settlement ratios. Higher bearing capacity and lower settlement were achieved by replacing the layers beneath the geocell layers with the rubber–soil mixture. At a ratio of settlement to plate diameter of 2%, the values of bearing pressure were in the ratio 1:2.3:3 for, respectively, the unreinforced installation, the installation with three layers of geocell, and the installation with three layers of geocell and rubber–soil between the layers. The inclusion of the geocell layers reduces the vertical stress transferred down through the foundation bed by distributing the load over a wider area. For example, at the pressure of 550 kPa applied on the soil surface, the transferred pressure at the depth of 510 mm is about 48%, 34% and 27% for the reinforced bed with one, two and three layers of geocell, respectively, compared with the stress in the unreinforced bed. Furthermore, use of the combination of geocell and rubber–soil mixture layers is more effective than use of geocell layers only in reducing the stress transferred downwards. For example, 350 mm beneath a soil surface that carries a stress of 830 kPa, the vertical stress is 15% less when two geocell layers are combined with two rubber–soil mixture layers than when there are only two geocell layers.
Experimental and DEM simulation of sandy soil reinforced with H–V inclusions in plane strain tests
Authors: Lin Y.L. , Zhang M.X. , Javadi A.A. , Lu Y. , Zhang S.L.
Published: June 2013

ABSTRACT: Horizontal–vertical (H–V) reinforcing elements are a new type of soil reinforcement in geotechnical engineering. The advantages of this reinforcement have been validated by a series of triaxial compression tests in which all of the three principal stresses play a role in the stress–strain–strength response. However, many geotechnical designs involve soil mass subjected to plane strain conditions. In this paper, laboratory plane strain compression tests were carried out with different heights of vertical inclusions along with horizontal reinforcement under four different confining stresses. In order to gain some insight into the driving micromechanics that govern the macroscale behaviour, the discrete-element method was used to model the behaviour of the reinforced soils and the modelling results were compared with the experimental results. The comparison showed that the predictions of the numerical analyses matched well with the experimental data in terms of macro-mechanical responses. Finally, it can be concluded from the analyses that a specified improvement in strength can be achieved using H–V inclusions compared with using only horizontal reinforcement.
Role of strain magnitude on the deformation response of geosynthetic-reinforced soil layers
Authors: McCartney J.S. , Cox B.R.
Published: June 2013

ABSTRACT: This paper reports an investigation into the deformation response of geosynthetic-reinforced soil layers to evaluate the level of strain required to mobilize reinforcement mechanisms during surface loading. Specifically, an assessment of data from previous studies reporting surface settlements of reinforced and unreinforced soil layers during monotonic or cyclic loading to failure is complemented with new dynamic tests performed at small- and medium-strain magnitudes. A series of test sections with and without geosynthetic reinforcement were characterized using a Vibroseis shaker truck as a dynamic loading source. The behavior of uniform sand layers under relatively small strain magnitudes (shear strain magnitudes less than 0.2%) were characterized using embedded geophones. Shear and normal strain distributions within the test sections were measured as a function of depth during application of surface shear loading. The presence of geosynthetic reinforcement (either geogrid or geotextile) at a depth of 254 mm below the surface of the sand layer does not significantly alter the distributions of shear strain or vertical normal strain relative to an unreinforced control section for the magnitudes of shear and compressive strains applied to the soil surface. The behavior of aggregate base layers overlying sand layers under medium strain magnitudes (surface deflections up to 25 mm) were characterized using an array of LVDTs on the soil surface. Surface deflection basins were measured during application of several thousand cycles of compressive loading. The presence of a geogrid within the aggregate base layer or a woven geotextile beneath the aggregate base layer were observed not to lead to a change in the surface deflection basins up to a maximum deflection of 25 mm. These observations, together with results from the literature, indicate that reinforcement mechanisms such as lateral restraint and the tensioned-membrane effect may not be mobilized until reaching relatively large displacements in some soil layers.
Behavior of nonwoven-geotextile-reinforced sand and mobilization of reinforcement strain under triaxial compression
Authors: Nguyen M.D. , Yang K.H. , Lee S.H. , Wu C.S. , Tsai M.H.
Published: June 2013

ABSTRACT: Laboratory triaxial compression tests were conducted to investigate the stress–strain–volumetric responses of geotextile-reinforced sand and the mobilization and distribution of reinforcement strain/loads and soil–geotextile interface shear stress within reinforced soil. Geotextile-reinforced sand specimens were tested while varying the confining pressures and number of geotextile reinforcement layers. A digital image-processing technique was applied to determine residual tensile strain of the reinforcements after tests and to estimate reinforcement tensile loads. Experimental results indicate that the geotextile reinforcement enhanced peak shear strength and axial strain at failure, and reduced loss of post-peak shear strength. The reinforced specimen had higher shear strength when compared with that of unreinforced soil after deforming by 1–3% of axial strain, which indicates that the geotextile requires a sufficient deformation to mobilize its tensile force to improve the shear strength of reinforced soil. For each reinforcement layer, mobilized tensile strain peaked at the center of the reinforcement and decreased along the radial direction, while the interface shear stress was zero at the center and peaked at a distance of 0.5–07 reinforcement radius from the center. The mobilized tensile strain of reinforcement increases as confining pressure and number of reinforcement layers increase. This work also demonstrates that the strength difference between reinforced and unreinforced soil was strongly correlated with the sum of maximum mobilized tensile forces of all reinforcement layers, indicating that mobilized tensile force of reinforcements directly improved the shear strength of reinforced soil. Last, a number of analytical models to predict peak shear strength of reinforced soil are verified experimentally. This verification demonstrates that mobilized tensile force rather than ultimate tensile strength can be used in analytical models.
Beams on extensible geosynthetics and stone-column-improved soil
Authors: Maheshwari Priti , Chauhan Vinay Bhushan
Published: June 2013

In the present study the response of rails, treated as infinite beams, resting on geosynthetic-reinforced granular fill on top of stone-column-treated soft soil, was studied under the action of moving loads. The granular fill layer was modelled as a Pasternak shear layer and the extensible geosynthetic layer as a rough elastic membrane. The stone columns and soft soil were idealised by non-linear Winkler springs and a Kelvin–Voigt body, respectively. Due consideration is given to the range of parametric values that are normally found to be valid in the case of railway tracks. A detailed parametric study revealed that the magnitude and velocity of a moving load, viscous damping, the diameter and spacing of stone columns, the ultimate bearing resistance of stone columns and the soft soil, tensile modulus of geosynthetics, relative compressibility of stone columns and average degree of consolidation significantly affect the response of the soil–foundation system.
Axial capacity and ductility of circular UHPC-filled steel tube columns
Authors: Guler Soner , Çopur Alperen , Aydogan Metin
Published: June 2013

This paper presents an experimental study of circular ultra-high-performance concrete-filled steel tube (UHPCFT) columns under monotonic axial compression. Some performance indices, termed concrete contribution ratio (CCR), strength enhancement index (SI) and ductility index (DI), are investigated in relation to the diameter-to-thickness ratio (D/t) of the UHPCFT columns. The axial bearing capacities of the UHPCFT columns obtained from the test results are compared with Eurocode 4, American Concrete Institute, Australian Standards and Architectural Institute of Japan design codes. The test results show that increasing the steel tube thickness from 2·5 mm to 3·65 mm enhances the DI by 69%, but the SI only by 5%. Although the Eurocode 4 design code overestimates the axial bearing capacities of the UHPCFT columns, the American Concrete Institute, Australian Standards and Architectural Institute of Japan codes are conservative.
Effects of specimen size and shape on compressive and tensile strengths of self-compacting concrete with or without fibres
Authors: Aslani Farhad
Published: June 2013

Self-compacting concrete (SCC) can be placed and compacted under its own weight. Modifications in the mix design of SCC may significantly influence the material's mechanical properties. Therefore, it is vital to investigate whether all the assumed hypotheses about conventional concrete also hold true for SCC structures. This paper discusses an experimental programme that was carried out to study the effects of specimen size and shape on the compressive and tensile strength of SCC and fibre reinforced SCC. For this purpose, cube specimens with 100 and 150 mm dimensions and cylinder specimens with 100 × 200 and 150 × 300 mm dimensions were casted. The experimental programme examined four SCC mixtures: plain SCC, and steel-, polypropylene- and hybrid-fibre reinforced SCC. Compressive and tensile strengths were tested after 3, 7, 14, 28 and 56 days. The paper also investigates correlations between compressive and tensile strengths and the size and shape of the specimen.
Quantifying the sampling error in tree census measurements by volunteers and its effect on carbon stock estimates
Authors: Butt Nathalie , Slade Eleanor , Thompson Jill , Malhi Yadvinder , Riutta Terhi
Published: June 2013

A typical way to quantify aboveground carbon in forests is to measure tree diameters and use species‐specific allometric equations to estimate biomass and carbon stocks. Using “citizen scientists” to collect data that are usually time‐consuming and labor‐intensive can play a valuable role in ecological research. However, data validation, such as establishing the sampling error in volunteer measurements, is a crucial, but little studied, part of utilizing citizen science data. The aims of this study were to (1) evaluate the quality of tree diameter and height measurements carried out by volunteers compared to expert scientists and (2) estimate how sensitive carbon stock estimates are to these measurement sampling errors. Using all diameter data measured with a diameter tape, the volunteer mean sampling error (difference between repeated measurements of the same stem) was 9.9 mm, and the expert sampling error was 1.8 mm. Excluding those sampling errors >1 cm, the mean sampling errors were 2.3 mm (volunteers) and 1.4 mm (experts) (this excluded 14% [volunteer] and 3% [expert] of the data). The sampling error in diameter measurements had a small effect on the biomass estimates of the plots: a volunteer (expert) diameter sampling error of 2.3 mm (1.4 mm) translated into 1.7% (0.9%) change in the biomass estimates calculated from species‐specific allometric equations based upon diameter. Height sampling error had a dependent relationship with tree height. Including height measurements in biomass calculations compounded the sampling error markedly; the impact of volunteer sampling error on biomass estimates was ±15%, and the expert range was ±9%. Using dendrometer bands, used to measure growth rates, we calculated that the volunteer (vs. expert) sampling error was 0.6 mm (vs. 0.3 mm), which is equivalent to a difference in carbon storage of ±0.011 kg C/yr (vs. ±0.002 kg C/yr) per stem. Using a citizen science model for monitoring carbon stocks not only has benefits in educating and engaging the public in science, but as demonstrated here, can also provide accurate estimates of biomass or forest carbon stocks.
Competition and facilitation between a native and a domestic herbivore: trade‐offs between forage quantity and quality
Authors: Augustine David J. , Springer Tim L.
Published: June 2013

Potential competition between native and domestic herbivores is a major consideration influencing the management and conservation of native herbivores in rangeland ecosystems. In grasslands of the North American Great Plains, black‐tailed prairie dogs (Cynomys ludovicianus) are widely viewed as competitors with cattle but are also important for biodiversity conservation due to their role in creating habitat for other native species. We examined spatiotemporal variation in prairie dog effects on growing‐season forage quality and quantity using measurements from three colony complexes in Colorado and South Dakota and from a previous study of a fourth complex in Montana. At two complexes experiencing below‐average precipitation, forage availability both on and off colonies was so low (12–54 g/m2) that daily forage intake rates of cattle were likely constrained by instantaneous intake rates and daily foraging time. Under these dry conditions, prairie dogs (1) substantially reduced forage availability, thus further limiting cattle daily intake rates, and (2) had either no or a small positive effect on forage digestibility. Under such conditions, prairie dogs are likely to compete with cattle in direct proportion to their abundance. For two complexes experiencing above‐average precipitation, forage quantity on and off colonies (77–208 g/m2) was sufficient for daily forage intake of cattle to be limited by digestion rather than instantaneous forage intake. At one complex where prairie dogs enhanced forage digestibility and [N] while having no effect on forage quantity, prairie dogs are predicted to facilitate cattle mass gains regardless of prairie dog abundance. At the second complex where prairie dogs enhanced digestibility and [N] but reduced forage quantity, effects on cattle can vary from competition to facilitation depending on prairie dog abundance. Our findings show that the high spatiotemporal variation in vegetation dynamics characteristic of semiarid grasslands is paralleled by variability in the magnitude of competition between native and domestic grazers. Competitive interactions evident during dry periods may be partially or wholly offset by facilitation during periods when forage digestibility is enhanced and forage quantity does not limit the daily intake rate of cattle.
Patch size and edge proximity are useful predictors of brood parasitism but not nest survival of grassland birds
Authors: Benson Thomas J. , Chiavacci Scott J. , Ward Michael P.
Published: June 2013

Declines of migratory birds have led to increased focus on causative factors for these declines, including the potential adverse effects of habitat fragmentation on reproductive success. Although numerous studies have addressed how proximity to a habitat edge, patch size, or landscape context influence nest survival or brood parasitism, many have failed to find the purported effects. Furthermore, many have sought to generalize patterns across large geographic areas and habitats. Here, we examined evidence for effects of edge proximity, patch size, and landscape context on nest survival and brood parasitism of grassland birds, a group of conservation concern. The only consistent effect was a positive association between edge proximity and brood parasitism. We examined effects of patch size on nest survival (37 studies) and brood parasitism (30 studies) representing 170 and 97 different estimates, respectively, with a total sample size of >14 000 nests spanning eastern North America. Nest survival weakly increased with patch size in the Great Plains, but not in the Midwestern or Eastern United States, and brood parasitism was inversely related to patch size and consistently greater in the Great Plains. The consistency in brood parasitism relative to nest survival patterns is likely due to parasitism being caused by one species, while nest survival is driven by a diverse and variable suite of nest predators. Often, studies assume that predators responsible for nest predation, the main driver of nest success, either are the same or exhibit the same behaviors across large geographic areas. These results suggest that a better mechanistic understanding of nest predation is needed to provide meaningful conservation recommendations for improving grassland bird productivity, and that the use of general recommendations across large geographic areas should only be undertaken when sufficient data are available from all regions.
Dissecting impact of plant invaders: Do invaders behave differently in the new range?
Authors: Sun Yan , Collins Alexandra R. , Schaffner Urs , Müller-Schärer Heinz
Published: June 2013

Knowledge from basic plant ecology suggests that impact of one plant species on another is driven by either competition for the same limiting resources, or by unique plant traits. These processes might be context specific, explaining a differential impact of exotic plant invaders in the native vs. introduced range. With the help of a conceptual framework, we aimed at identifying the relationship between invader biomass and impact in the invasive Centaurea stoebe by conducting pairwise competition experiments with 15 European (old) and 15 North American (new) neighboring species. Old neighbors grew larger and could use available soil moisture more efficiently for growth than new neighbors. Interestingly, biomass of C. stoebe explained a substantial amount of the variation in biomass of the coevolved neighbors, but not of the new “naïve” neighbors. Thus, impact in the home range appears to be driven by competition for the same limiting resources, but by other factors in the introduced range, possibly by exploitation of resources that are not used by the new neighbors or by interference competition. This distinction has important consequences for the management of invasive species, as in our study ecosystem recovery is less likely after simple biomass reduction.
The dynamics of community assembly under sudden mixing in experimental microcosms
Authors: Livingston George , Jiang Yuexin , Fox Jeremy W. , Leibold Mathew A.
Published: June 2013

Landscape connectivity has been shown to alter community assembly and its consequences. Here we examine how strong, sudden changes in connectivity may affect community assembly by conducting experiments on the effects of “community mixing,” situations where previously isolated communities become completely connected with consequent community reorganization. Previous theory indicates that assembly history dictates the outcome of mixing: mixing randomly assembled communities leads to a final community with random representation from the original communities, while mixing communities that were assembled via a long history of colonizations and extinctions leads to strong asymmetry, with one community dominating the other. It also predicts that asymmetry should be stronger in the presence of predators in the system. We experimentally tested and explored this theory by mixing aquatic microcosms inhabited by a complex food web of heterotrophic protists, and algae. Our results confirm the prediction that long assembly history can produce asymmetry under mixing and suggest these dynamics could be important in natural systems. However, in contrast to previous theory we also found asymmetry weaker under mixing of communities with more complex trophic structure.
Cognitive Load and Goal Based Scenario Centered 3D Multimedia Learning Environment: Learners' Motivation, Satisfaction and Mental Effort
Authors: Kilic Eylem , Yildirim Zahide
Published: June 2013

This study investigated the learners' satisfaction, motivation, and mental effort in Goal Based Scenario centered 3D multimedia learning environment (GBSc3DM). The design of the GBSc3DM was based on the Cognitive Load Theory (CLT) principles. Two versions of the GBSc3DM were developed. While Cognitive Load Theory principles were taken into account and implemented in the design of the first version (+CLT), those principles were not applied in the design of the second version (–CLT). A total of 82 9th grade high school students participated in the study. Mixed methods were used to gather the data. The findings of the study revealed that the learners were satisfied with the Goal Based Scenario components and the CLT principles implemented in the first version of GBSc3DM. The learners pointed out that GBSc3DM and CLT principles motivated them to learn the topic. However, not only were the learners not satisfied with the second version (–CLT), but they also found it distracting. The findings showed that the learners invested higher mental effort in the second version (–CLT) of GBSc3DM.
Mediterranean Diet, Kidney Function, and Mortality in Men with CKD
Authors: Huang Xiaoyan , Jiménez-Moleón José Juan , Lindholm Bengt , Cederholm Tommy , Ärnlöv Johan , Risérus Ulf , Sjögren Per , Carrero Juan Jesús
Published: June 2013

Background and objectives

Adherence to a Mediterranean diet may link to a better preserved kidney function in the community as well as a favorable cardiometabolic profile and reduced mortality risk in individuals with manifest CKD.

Design, setting, participants, & measurements

Dietary habits were determined by 7-day dietary records in a population-based cohort of 1110 Swedish men (age 70 years) from 1991 to 1995, 506 of whom were considered to have CKD because of a GFR<60 ml/min per 1.73 m2. A Mediterranean Diet Score was calculated, and participants were categorized as having low, medium, or high adherence. Adequate dietary reporters were identified with Goldberg cutoffs (n=597). Deaths were registered during a median follow-up of 9.9 years.

Results

Compared with low adherents, medium and high adherents were 23% and 42% less likely to have CKD, respectively (adjusted odds ratio [95% confidence interval]=0.77 [0.57 to 1.05] and 0.58 [0.38 to 0.87], respectively, P for trend=0.04). Among those individuals with CKD, phosphate intake and net endogenous acid production were progressively lower across increasing adherence groups. No differences were observed regarding other cardiometabolic risk factors across adherence groups. As many as 168 (33%) CKD individuals died during follow-up. Compared with low adherents, proportional hazards regression associated medium and high adherents to a 25% and 23% lower mortality risk, respectively (adjusted hazard ratio [95% confidence interval]=0.75 [0.52 to 1.06] and 0.77 [0.44 to 1.36], respectively, P for trend=0.10). Sensitivity analyses showed significant and stronger associations when only adequate dietary reporters were considered.

Conclusions

Adherence to a Mediterranean dietary pattern is associated with lower likelihood of CKD in elderly men. A greater adherence to this diet independently predicted survival in those patients with manifest CKD. Clinical trials are warranted to test the hypothesis that following such a diet could improve outcomes (independent of other healthy lifestyles) in CKD patients.
Five Policies to Promote Palliative Care for Patients with ESRD
Authors: Kurella Tamura Manjula , Meier Diane E.
Published: June 2013

Patients with ESRD experience complex and costly care that does not always meet their needs. Palliative care, which focuses on improving quality of life and relieving suffering for patients with serious illnesses, could address a large unmet need among patients with ESRD. Strengthening palliative care is a top policy priority for health reform efforts based on strong evidence that palliative care improves value. This commentary outlines palliative care policies for patients with ESRD and is directed at policymakers, dialysis providers, nephrology professional societies, accreditation organizations, and funding agencies who play a key role in the delivery and determination of quality of ESRD care. Herein we suggest policies to promote palliative care for patients with ESRD by addressing key barriers, including the lack of access to palliative care, lack of capacity to deliver palliative care, and a limited evidence base. We also provide examples of how these policies could be implemented within the existing ESRD care infrastructure.
Re-envisioning Fistula First in a Patient-Centered Culture
Authors: Gomes Amanda , Schmidt Rebecca , Wish Jay
Published: June 2013

The main options for vascular access in hemodialysis patients are arteriovenous fistulas (AVFs), arteriovenous grafts, and tunneled cuffed central venous catheters. AVFs have the lowest complication rate and require the fewest interventions and lowest cost to maintain. There has been a dramatic national increase in prevalent AVFs among patients with ESRD in the United States driven, in part, by the Fistula First Breakthrough Initiative. The Fistula First Breakthrough Initiative has engaged stakeholders in the dialysis community to disseminate best practices and quality improvement activities to increase AVF prevalence in suitable candidates. In the pursuit of maximizing AVF placement and prevalence, less emphasis has been placed on the individual patient context. An AVF may not be the best access choice in a subset of patients, particularly those with poor long-term prognoses or comorbid chronic diseases with a short life expectancy, those patients more likely to die than to have their CKD progress to ESRD requiring dialysis, and those with vascular anatomy not amenable to successful AVF placement. Placement of an AVF in these patients subjects them to uncomfortable and likely unnecessary and/or unsuccessful surgeries at an expense, while doing little to improve their clinical outcome or their individual experience of care. AVF prevalence as a pay-for-performance measure without the appropriate case-mix adjustment may penalize providers for accepting higher-risk patients. Although a functioning AVF that provides reliable hemodialysis remains the gold standard for vascular access for most patients, it may not be the most suitable option for every patient.
Association of Plasma Des-acyl Ghrelin Levels with CKD
Authors: Gupta Rohit K. , Kuppusamy Tamil , Patrie James T. , Gaylinn Bruce , Liu Jianhua , Thorner Michael O. , Bolton Warren K.
Published: June 2013

Background and objectives

There are no effective therapies for malnutrition in CKD/ESRD patients. This study hypothesized that ghrelin, an endogenous orexigenic hormone, would correlate with renal function and might suggest therapeutic interventions for CKD/ESRD malnutrition.

Design, setting, participants, & measurements

Fifty-one CKD and 15 hemodialysis patients were enrolled. Acyl ghrelin (AG) and des-acyl ghrelin (DG) were determined using separate two-site–specific assays. Leptin, insulin, growth hormone, insulin-link growth factor-1, C-reactive protein, TNF-α, and IL-6 were also measured.

Results

Univariate correlation analyses showed that CKD stage was highly, positively correlated with the levels of preprandial and postprandial DG and positively correlated with TNF-α, IL-6, leptin, and age. Multivariate partial-correlation analyses showed that CKD was independently associated with the proportion of preprandial and postprandial DG, whereas TNF-α, IL-6, leptin, insulin, and age were not independently associated with either. Geometric mean (GM) preprandial and postprandial AG were comparable between CKD stages ≤2 and >2, whereas GM preprandial DG and postprandial DG were 1.95-fold and 2.17-fold greater, respectively, for CKD stage >2 versus stage ≤2. DG was the dominant form of ghrelin preprandially and postprandially for both CKD stages ≤2 and >2. Dialysis had no effect on AG, but reduced DG by 73% to levels even lower (GM 48.7 pg/ml) than those seen postprandially in CKD stage ≤2 patients (GM 77.0 pg/ml).

Conclusions

This study shows a strong and independent correlation of DG with CKD stage. Postprandial suppression of ghrelin is impaired with reduced renal function. Hemodialysis selectively removes DG but not AG.
Three-dimensional analysis of effects of rapid maxillary expansion on facial sutures and bones: A systematic review
Authors: Bazargani Farhan , Feldmann Ingalill , Bondemark Lars
Published: June 2013

Objective:

To evaluate the evidence on three-dimensional immediate effects of rapid maxillary expansion (RME) treatment on growing patients as assessed by computed tomography/cone beam computed tomography (CT/CBCT) imaging.

Materials and Methods:

The published literature was searched through the PubMed, Embase, and Cochrane Library electronic databases from January 1966 to December 2012. The inclusion criteria consisted of randomized controlled trials, prospective controlled studies, and prospective case-series. Two reviewers extracted the data independently and assessed the quality of the studies.

Results:

The search strategy resulted in 73 abstracts or full-text articles, of which 10 met the inclusion criteria. When treating posterior crossbites with a RME device, the existing evidence points out that the midpalatal suture opening is around 20%–50% of the total screw expansion. There seems to be no consistent evidence on whether the midpalatal sutural opening is parallel or triangular. The effect on the nasal cavity dimensions after RME seems to be apparent and indicates an enlargement between 17% and 33% of the total screw expansion. Circummaxillary sutures, particularly the zygomaticomaxillary and frontomaxillary sutures and also spheno-occipital synchondrosis, appear to be affected by the maxillary expansion. Overall, however, the changes were small and the evidence not conclusive.

Conclusions:

CT imaging proved to be a useful tool for assessment of treatment effects in all three dimensions. The majority of the articles were judged to be of low quality, and therefore, no evidence-based conclusions could to be drawn from these studies.
Effects of Chemical Reaction on MHD Flow Past an Impulsively Started Infinite Vertical Plate with Uniform Heat and Mass Flux
Authors: Chandrakala P.
Published: June 2013

Finite difference solutions of the unsteady MHD flow past an impulsively started infinite vertical plate with uniform heat and mass flux are presented here, taking into account the homogeneous chemical reaction of first order. The dimensionless governing equations are solved by an efficient, more accurate, unconditionally stable and fast converging implicit scheme. The effects of velocity, temperature and concentration for different parameters such as chemical reaction parameter, Schmidt number, Prandtl number, thermal Grashof number, mass Grashof number and time are studied. It is observed that due to the presence of a first order chemical reaction, the velocity increases during the generative reaction and decreases in the destructive reaction. It is observed that the velocity decreases in the presence of the magnetic field, as compared to its absence.
Optimization of Pin Fin Heat Sink by Application of CFD Simulations and Doe Methodology with Neural Network Approximation
Authors: Kasza K. , Malinowski Ł. , Królikowski I.
Published: June 2013

A design optimization of a staggered pin fin heat sink made of a thermally conductive polymer is presented. The influence of several design parameters like the pin fin height, the diameter, or the number of pins on thermal efficiency of the natural convection heat sink is studied. A limited number of representative heat sink designs were selected by application of the design of experiments (DOE) methodology and their thermal efficiency was evaluated by application of the antecedently validated and verified numerical model. The obtained results were utilized for the development of a response surface and a typical polynomial model was replaced with a neural network approximation. The particle swarm optimization (PSO) algorithm was applied for the neural network training providing very accurate characterization of the heat sink type under consideration. The quasi-complete search of defined solution domain was then performed and the different heat sink designs were compared by means of thermal performance metrics, i.e., array, space claim and mass based heat transfer coefficients. The computational fluid dynamics (CFD) calculations were repeated for the most effective heat sink designs.
A Simple Algorithm for Simultaneous Sine Signal Parameters Estimation
Authors: Petrović Predrag B.
Published: June 2013

This paper presents a new algorithm based on the use of partial derivatives of the processed signal and the weighted estimation procedure to estimate the fundamental frequency, the amplitude and the phase of sinusoidal signal. The proposed algorithm is able to estimate the signal parameters simultaneously, supposing the time-varying frequency. The simulation results verify the effectiveness of the proposed algorithm.
Offline and Online Modelling of Switched Reluctance Motor Based on RBF Neural Networks
Authors: Cai Jun , Deng Zhiquan
Published: June 2013

Due to the highly nonlinearity of the flux-linkage characteristics of Switched Reluctance Motor drives (SRM), accurately modelling is cumbersome. In this paper, the offline- trained and the online-trained Radial Basis function (RBF) neural network model are proposed for estimating the SRM flux-linkage under running conditions. To investigate the performance of the modelling schemes, the simulation and experiments have been implemented in a 12/8 structure SRM prototype. The results show that the online-trained model exhibits much better estimation accuracy and robustness than the offline-trained model. Thus, the online-trained RBF model is more suitable for SRM performance prediction and analyzing.
Antibody-Mediated Rejection in Kidney Transplant Recipients
Authors: Rozentâls Rafails , Ziediņa Ieva
Published: June 2013

This paper provides a review of the significant problem of humoral, or antibody-mediated rejection, in kidney transplantation. The main cause of antibody-mediated rejection is donor-specific anti-HLA antibodies. Patients with anti-HLA antibodies are called sensitised patients. The outcome of humoral rejection is unfavourable: graft dysfunction and failure have been frequent from the early post-transplant period and are continuing. International laboratories and clinics offer sensitive and accurate methods to determine antibodies before and after kidney transplantation, but the methods are not always successful in recognition of sensitised patients. For diagnostics of humoral rejection the important issue is detecting complement breakdown deposition (C4d) in peritubular capillaries during immunohistological examination. On the one hand, their presence is characteristic for humoral rejection, but on the other hand, they can occur without any clinical changes or can remain undetected during severe humoral rejection. Current methods of prevention, diagnostics and treatment of humoral rejection are discussed. Difficulties of evaluation of chronic antibody-mediated injury are particularly highlighted.