bluuebunny/crossref_metadata_2025 huggingface dataset:
Julius Sachs (1868): The father of plant physiology
Authors: Kutschera Ulrich , Niklas Karl J.
Published: May 2018

The year 2018 marks the 150th anniversary of the first publication of Julius von Sachs' (1832–1897) Lehrbuch der Botanik (Textbook of Botany), which provided a comprehensive summary of what was then known about the plant sciences. Three years earlier, in 1865, Sachs produced the equally impressive Handbuch der Experimental‐Physiologie der Pflanzen (Handbook of Experimental Plant Physiology), which summarized the state of knowledge in all aspects of the discipline known today as plant physiology. Both of these books provided numerous insights based on Sachs' seminal experiments. By virtue of a reliance on detailed empirical observation and the rigorous application of chemical and physical principles, it is fair to say that the publication of these two monumental works marked the beginning of what can be called “modern‐day” plant science. Moreover, Sachs' Lehrbuch der Botanik prefigured the ascendance of plant molecular biology and the systems biology of photoautotrophic organisms. Regrettably, many of the insights of this great scientist have been forgotten by the generations who followed. It is only fitting, therefore, that the anniversary of the publication of the Lehrbuch der Botanik and the career of “the father of plant physiology” should be honored and reviewed, particularly because Sachs established the physiology of green organisms as an integral branch of botany and incorporated a Darwinian perspective into plant biology. Here we highlight key insights, with particular emphasis on Sachs' detailed discussion of sexual reproduction at the cellular level and his endorsement of Darwinian evolution.
Target sequence capture of nuclear‐encoded genes for phylogenetic analysis in ferns
Authors: Wolf Paul G. , Robison Tanner A. , Johnson Matthew G. , Sundue Michael A. , Testo Weston L. , Rothfels Carl J.
Published: May 2018

Premise of the Study

Until recently, most phylogenetic studies of ferns were based on chloroplast genes. Evolutionary inferences based on these data can be incomplete because the characters are from a single linkage group and are uniparentally inherited. These limitations are particularly acute in studies of hybridization, which is prevalent in ferns; fern hybrids are common and ferns are able to hybridize across highly diverged lineages, up to 60 million years since divergence in one documented case. However, it not yet clear what effect such hybridization has on fern evolution, in part due to a paucity of available biparentally inherited (nuclear‐encoded) markers.

Methods

We designed oligonucleotide baits to capture 25 targeted, low‐copy nuclear markers from a sample of 24 species spanning extant fern diversity.

Results

Most loci were successfully sequenced from most accessions. Although the baits were designed from exon (transcript) data, we successfully captured intron sequences that should be useful for more focused phylogenetic studies. We present phylogenetic analyses of the new target sequence capture data and integrate these into a previous transcript‐based data set.

Discussion

We make our bait sequences available to the community as a resource for further studies of fern phylogeny.
Synthesis of Black Phosphorus Quantum Dots with High Quantum Yield by Pulsed Laser Ablation for Cell Bioimaging
Authors: Ren Xin , Zhang Fang , Zhang Xiaoling
Published: May 2018

Black phosphorus quantum dots (BPQDs), with an average diameter of about 6 nm and a height of about 1.1 nm, are successfully synthesized by means of a pulsed laser ablation (PLA) method in isopropyl ether (IPE) solvent. The photoluminescence PL quantum yield of the as‐prepared sample is as high as 20.7 %, which is 3 times that of BPQDs prepared by means of probe ultrasonic exfoliation (approximately 7.2 %). The stable and blue–violet PL emission of the BPQDs is observed. It can be elucidated that electrons transit from the LUMO energy level to the HOMO energy level, as well as energy levels below the HOMO (H1 and H2). In addition, BPQDs are also utilized in bioimaging in HeLa cells, showing an intense and stable PL signal and excellent biocompatibility. Hence, this work indicates that the obtained BPQDs with high quantum yield and stable PL emission have great potential for biomedical applications, including biolabeling, bioimaging, and drug delivery.
Elongated transverse aortic arch in subjects without turner syndrome: A preliminary computed tomography study
Authors: Ece B. , Yiğit H. , Ergün E. , Koşar P. N.
Published: May 2018

The purpose of the present study was to investigate the presence of an elongated transverse aortic arch (ETA), which has been reported to be specific for Turner syndrome, in a population without Turner syndrome. A set of 1,012 patients (713 men, 299 women) under 40 years old, who underwent thoracic CT examination in our radiology department between July 2016 and December 2016, were included in the study. CT scans were performed by 16‐slice scanners. CT images were retrieved from the picture archiving and communication system and retrospectively re‐assessed by two radiologists. Diagnostic criteria for ETA, which are late take‐off of the left subclavian artery (LSA), convex kinking of the inferior aortic arch along the lesser curvature and flattening of the transverse aortic arch, were searched in each case. The mean age of the study population was 25.5 ± 10.0 years. Late take‐off of the LSA was detected in 17 (1.7%) subjects (10 men, 7 women). In six of these, the other criteria for ETA were not met. However, in the other 11 (1.1% of the study population) cases, in addition to late take‐off of the LSA, aortic morphology was compatible with ETA. The dimensions of the aortic root and the ascending and descending aorta were within normal limits in all 17 cases. Our results supported the presence of ETA in subjects without Turner syndrome with ∼1.1% frequency. This is the first preliminary report regarding the frequency of ETA in non‐Turner subjects. Clin. Anat. 31:887–890, 2018. © 2018 Wiley Periodicals, Inc.
Ultrafine MoP Nanoparticles Well Embedded in Carbon Nanosheets as Electrocatalyst with High Active Site Density for Hydrogen Evolution
Authors: Lan Kai , Wang Xiang , Yang Haidong , Iqbal Kanwal , Zhu Yan , Jiang Pengbo , Tang Yu , Yang Yuanyuan , Gao Wenbin , Li Rong
Published: May 2018

Electrocatalysis of the hydrogen evolution reaction (HER) is a promising route for sustainable hydrogen production based on water splitting. Designing MoP nanoparticles as catalysts is a feasible strategy to enhance the electrocatalytic performance for HER. In response, we report the fabrication of ultrafine MoP nanoparticles (NPs) which are uniformly embedded on glucose‐derived phosphorus and nitrogen co‐doped carbon nanosheets (MoP/NPG) as an effective electrocatalyst for HER via a novel and simple solid‐state reaction. Transmission electron microscopy reveals that the resulting product exhibits an average size of 3.15 nm. Due to the presence of exposed active sites in ultrafine MoP NPs and the laminar structure of carbon nanosheets, the MoP/NPS shows remarkable high catalytic activity having a low overpotential of 90 and 115 mV to achieve the current density of 10 mA cm−2 in both, acidic and alkaline media, which demonstrates the promising potential for an application in sustainable energy production.
Amino Acid Based Self‐assembled Nanostructures: Complex Structures from Remarkably Simple Building Blocks
Authors: Chakraborty Priyadarshi , Gazit Ehud
Published: May 2018

Amino acids are the simplest biological building blocks capable of forming discreet nanostructures by supramolecular self‐assembly. The understanding of the process of organization of amino acid nanostructures is of fundamental importance for the study of metabolic diseases as well as for materials science applications. Although peptide self‐assembled structures have been the topic of many review articles, much less attention has been devoted to the ability of amino acid building blocks, both natural and synthetic, to form ordered assemblies with defined architectures and notable physical properties, by the process of self‐association. Herein, we try to shed light on amino acid based nanostructures, their fabrication and implications. We discuss self‐assembled nanostructures, including hydrogels with nano‐scale order, obtained from both modified and unmodified single amino acids. We also envision some future prospects in this emerging field.
Human Intestinal Enteroids for the Study of Bacterial Adherence, Invasion, and Translocation
Authors: Poole Nina M. , Rajan Anubama , Maresso Anthony W.
Published: May 2018

Adherence, invasion, and translocation to and through the intestinal epithelium are important drivers of disease for many enteric bacteria. However, most work has been limited to transformed intestinal cell lines or murine models that often do not faithfully recapitulate key elements associated with human disease. The recent technological advances in organotypic tissue and cell culture are providing unparalleled access to systems with human physiology and complexity. Human intestinal enteroids (HIEs), derived from patient biopsy or surgical specimens of intestinal tissues, are organotypic cultures now being adapted to the study of enteric infections. HIEs are comprised of the dominant cell types of the human gastrointestinal epithelium, can be grown in two‐ or three‐dimensional structures, form a crypt–villus axis with defined apical and basolateral compartments, and undergo physiologic responses to many different stimuli. Here, we describe a series of protocols that encompass the use of human enteroids for the measurement of the adherence, invasion, and translocation of E. coli to and through the intestinal epithelium. We also outline the steps needed to grow and prepare enteroids for this purpose and highlight some common problems to troubleshoot. © 2018 by John Wiley & Sons, Inc.
Fully parameterized fixed‐order controller design for H∞ loop shaping method using frequency responses—extension to MIMO systems
Authors: Usami Tomohiro , Yubai Kazuhiro , Yashiro Daisuke , Komada Satoshi
Published: May 2018

Robust control is often applied to systems with uncertainties and disturbances. Above all, the H∞ loop shaping method is known to achieve good control performance and robustness. In this method, the final controller consists of weighting functions and a stabilizing controller. The stabilizing controller is derived for the shaped plant to suppress the H∞ norm of the transfer matrix consisting of a sensitivity function, a complementary sensitivity function, and so on. In addition, the stabilizing controller improves robust stability margin while keeping gain characteristic of the shaped plant if weighting functions are suitable. As a result, the closed‐loop system is well‐balanced between good tracking and robustness. However, a final controller tends to be high‐order. For this problem, reduction techniques are often applied to the final controller. In this case, performance and stability is not always adequately evaluated due to errors by the controller reduction. This paper proposes a fully parameterized fixed‐order controller design method using frequency responses of the plant. We formulate a design problem for multi‐input–multi‐output systems as an optimization problem. Therefore, we can directly design a low‐order controller from frequency responses using the iterative LMI optimization. Accordingly, we can avoid to deteriorate the evaluation of performance and stability.
Phosphonated Lipids as Primary Plasticizers for PVC with Improved Flame Retardancy
Authors: Bocqué Maeva , Lapinte Vincent , Courault Valérie , Couve Joel , Cassagnau Philippe , Robin Jean‐Jacques
Published: May 2018

Bio‐based plasticizers bearing moieties exhibiting flame retardancy properties [dimethyl (methyl oleate)phosphonate (PMO), diethyl (methyl oleate)phosphonate (PMO2), dimethyl (methyl linoleate)phosphonate (PML), dimethyl (dimethyl oleate)phosphonate (PDE)] are synthesized from methyl oleate, methyl linoleate, and oleic diacid through free‐radical addition of dialkyl phosphonates. Soft PVC is prepared from PMO, PMO2, PML, and PDE primary plasticizers and compared to materials containing usual diisononyl phthalate DINP. Rheological behavior, thermal stability, mechanical properties, and flame resistance performances of these PVC films are carefully investigated. The presence of the phosphonate group into the plasticizer structure explains the best thermal stability of the PVC films based on phosphonated plasticizer than that of based on DINP. Regarding all these results, PMO and PDE can be considered as efficient flame retardant primary plasticizers for PVC and can substitute phthalates in soft PVC based materials.

Practical Applications: These biobased additives are elaborated as plasticizers for PVC improving flame retardancy.

Lipids were investigated as additives for polymeric materials. Looking at replacing phthalates in soft PVC formulations, phosphonated lipids demonstrate both a flame‐retardant efficiency and plasticizing properties (mechanical properties, gelation temperature) for this polymer.
Defective Bi2WO6‐Supported Cu Nanoparticles as Efficient and Stable Photoelectrocatalytic for Water Splitting in Near‐Neutral Media
Authors: Li Junqi , Liang Zheng , Qin Yi , Guo Liu , Lei Nan , Song Qianqian
Published: May 2018

Defective Bi2WO6‐supported Cu nanoparticles photoelectrocatalyst were successfully synthesized via an etching approach by using NaBH4 as reducing agent. The as‐prepared Cu/Bi2WO6‐1 was dominated by CuO and Cu and Cu/Bi2WO6‐2 was dominated by metallic Cu, confirmed by XPS and TEM analyses. These etching pretreatments also induced the formation of defect sites such as oxygen vacancies and W5+. The presence of oxygen vacancies could significantly increase the photogenerated electrons capture abilities. Metallic Cu nanocrystals on the surface of Bi2WO6 photoanodes are beneficial for the photoresponse range as well as the separation and consumption of photogenerated carriers due to the surface plasmon resonance effect of Cu. Photoelectrochemical studies demonstrated that Cu/Bi2WO6‐x exhibited a markedly improved PEC performance in water splitting reaction as compared to that of Bi2WO6 which mainly because of the light harvesting efficiency (ηabs) and the interfacial charge transfer efficiency. Importantly, Cu/Bi2WO6‐2 exhibited the best PEC activity with a high current density and good stability under neutral conditions, which may be ascribed to the defective Bi2WO6 structure in combination with surface ligand engineering and the synergistic effect of oxygen vacancies and metallic Cu. In addition, the function mechanism of CuO, metallic Cu and oxygen vacancies were discussed in details.
Risk factors associated with preterm delivery and low delivery weight among HIV‐exposed neonates in China
Authors: Wang Liming , Zhao Hongxin , Cai Weiping , Tao Jie , Zhao Qingxia , Sun Lijun , Fan Qingbo , Kourtis Athena P. , Shepard Colin , Zhang Fujie
Published: May 2018

Objective

To examine the relationship between combination antiretroviral therapy (cART) and preterm delivery (PTD) or low delivery weight among pregnant Chinese women with HIV.

Methods

The present retrospective cross‐sectional medical chart review enrolled pregnant women with HIV who delivered at five tertiary hospitals in China between January 1, 2009, and December 31, 2014. Generalized linear mixed modeling was used to explore PTD (<37 weeks of pregnancy) and low delivery weight (<2500 g) risk factors.

Results

Among 731 mother–neonate pairs, 93 (12.7%) mothers had PTD and 133 (18.2%) neonates had low delivery weight. Use of cART pre‐conception or its initiation in the first trimester was associated with PTD (adjusted odds ratio [aOR] 2.82; P=0.002) and low delivery weight (aOR 1.92; P=0.026). First‐trimester cART initiation was associated with PTD for lopinavir/ritonavir (aOR 2.59; P=0.006) and nevirapine (aOR, 2.64; P=0.003) regimens compared with later; the same was not true for efavirenz‐based cART (P=0.197). Low maternal body mass index (≤23.5) before delivery was independently associated with an increased likelihood of low delivery weight (aOR 1.60; P=0.038) but not PTD.

Conclusion

Early use of cART was associated with increased likelihood of PTD and low delivery weight. Efavirenz‐based cART appeared to be favorable for women with HIV regardless of the timing of cART initiation. Good nutritional status is essential to prevent low delivery weight.
Teaching preschool children to report suspicious packages to adults
Authors: May Michael E. , Shayter Ashley M. , Schmick Ayla , Barron Becky , Doherty Meghan , Johnson Matthew
Published: May 2018

Law enforcement agencies stress that public reporting of terror‐related crime is the predominant means for disrupting these actions. However, schools may be unprepared because the majority of the populace may not understand the threat of suspicious materials or what to do when they are found on school grounds. The purpose of this study was to systematically teach preschool children to identify and report suspicious packages across three experiments. In the first experiment, we used multiple exemplar training to teach children to identify the characteristics of safe and unsafe packages. In the second experiment, we taught participants to identify the locations where packages should be considered unsafe. Finally, in the third experiment, we used behavioral skills training to teach participants to avoid touching unsafe packages, leave the area where they were located, and report their discovery to an adult. Results suggest the participants quickly developed these skills. Implications for safety skills in young school children are discussed.
Exploiting tail shape biases to discriminate between stable and student t alternatives
Authors: Sun Pengfei , de Vries Casper G.
Published: May 2018

The nonnormal stable laws and Student t distributions are used to model the unconditional distribution of financial asset returns, as both models display heavy tails. The relevance of the two models is subject to debate because empirical estimates of the tail shape conditional on either model give conflicting signals. This stems from opposing bias terms. We exploit the biases to discriminate between the two distributions. A sign estimator for the second‐order scale parameter strengthens our results. Tail estimates based on asset return data match the bias induced by finite‐variance unconditional Student t data and the generalized autoregressive conditional heteroscedasticity process.
Isotropic differential phase contrast microscopy for quantitative phase bio‐imaging
Authors: Chen Hsi‐Hsun , Lin Yu‐Zi , Luo Yuan
Published: May 2018

Quantitative phase imaging (QPI) has been investigated to retrieve optical phase information of an object and applied to biological microscopy and related medical studies. In recent examples, differential phase contrast (DPC) microscopy can recover phase image of thin sample under multi‐axis intensity measurements in wide‐field scheme. Unlike conventional DPC, based on theoretical approach under partially coherent condition, we propose a new method to achieve isotropic differential phase contrast (iDPC) with high accuracy and stability for phase recovery in simple and high‐speed fashion. The iDPC is simply implemented with a partially coherent microscopy and a programmable thin‐film transistor (TFT) shield to digitally modulate structured illumination patterns for QPI. In this article, simulation results show consistency of our theoretical approach for iDPC under partial coherence. In addition, we further demonstrate experiments of quantitative phase images of a standard micro‐lens array, as well as label‐free live human cell samples.
Effect of silicon‐doped calcium phosphate bone grafting materials on bone regeneration and osteogenic marker expression after implantation in the ovine scapula
Authors: Knabe Christine , Adel‐Khattab Doaa , Hübner Wolf‐Dietrich , Peters Fabian , Knauf Tom , Peleska Barbara , Barnewitz Dirk , Genzel Antje , Kusserow Roderik , Sterzik Florian , Stiller Michael , Müller‐Mai Christian
Published: May 2018

Compared to the currently clinically available bone grafting materials for alveolar ridge augmentation, there is a great demand for bioactive bone substitutes with higher resorbability, which enhance osteogenesis at the same time. This has prompted the development of a silicon‐doped rapidly resorbable calcium alkali orthophosphate (Si‐CAOP) and silicon‐doped β‐tricalcium phosphate (Si‐TCP). This study evaluated the effect of these two particulate graft materials as compared to the currently clinically used β‐TCP on bone formation and osteogenic marker expression after 2 weeks, 1, 3, 6, 12, and 18 months of implantation in critical size defects in the sheep scapula. Immunohistochemical analysis of collagen type I, alkaline phosphatase, and osteocalcin expression was performed on resin embedded sections. The bone and particle area fraction and the bone‐biomaterial contact were determined histomorphometrically. After 2 weeks and 1 month defects grafted with Si‐CAOP displayed a significantly greater bone area fraction, bone‐particle‐contact, osteogenic marker expression and significantly lower particle area fraction than defects grafted with Si‐TCP and TCP. By 3 and 6 months all materials studied mediated excellent defect regeneration with further bone remodeling at 12 and 18 months. Taken together, Si‐CAOP induced the most expeditious bone regeneration of critical size defects in the sheep scapula. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 594–614, 2019.
Highly efficient hemicellulose utilization for acetoin production by an engineered Bacillus subtilis
Authors: Li Xinli , Huang Can , Yu Xinlei , Liu Shuang , Wang Zhiwen , Tang Ya‐Jie , Chen Tao
Published: May 2018

BACKGROUND

Hemicellulose is considered one of the most abundant renewable bio‐resources and has been utilized as substrate for the manufacture of numerous bio‐products through microbiological approaches. However, it has rarely been reported that acetoin was produced directly from hemicellulose by microbial fermentation via consolidated bioprocessing (CBP).

RESULTS

To achieve efficient xylan utilization, four endo‐1,4‐beta‐xylanase and three β‐xylosidase were co‐overexpressed in Bacillus subtilis. Among the resulting engineered strains, BSL24, harboring xyn10B (from Clostridium stercorarium) and xsa (from Selenomonas ruminantium GA192) expression plasmid pHP13‐E2X4 exhibited the best fermentation performance in xylan degradation with relatively high endo‐1,4‐beta‐xylanase and β‐xylosidase activities, reaching 937.5 and 68 U L−1, respectively. The activities of the two enzymes were further improved by 83.0% and 124.6%, respectively, by using yeast extract as nitrogen source. Moreover, the addition of 0.25% v/w D‐valine can further stimulate the total activity of endo‐1,4‐beta‐xylanase in the cultures. Finally, pHP13‐E2X4 was introduced in an acetoin‐producing strain (168ARSRCPΔacoAΔbdhA), and the resulting strain BSL24AC produced 6.9 g L−1 acetoin from 1 g L−1 xylose and 19 g L−1 xylan in 96 h, with a yield of 0.345 g g−1, corresponding to 72.6% of the theoretical yield. When the xylan concentration was increased to 49 g L−1, BSL24AC produced 15 g L−1 acetoin in 132 h, corresponding to an acetoin yield of 0.300 g g−1 total sugar.

CONCLUSIONS

Bacillus subtilis was engineered to directly utilize hemicellulose by co‐overexpression of different xylan hydrolases. To the best of our knowledge, this is the first study on efficient production of acetoin from hemicellulose via CBP in Bacillus subtilis. © 2018 Society of Chemical Industry
Surfactant effects on wettability of Penicillium frequentans formulations to improve brown rot biocontrol
Authors: Guijarro Belén , Larena Inmaculada , Melgarejo Paloma , De Cal Antonieta
Published: May 2018

BACKGROUND

Penicillium frequentans can be used in the management of brown rot caused by Monilinia spp. Competition is the primary mode of biocontrol activity of P. frequentans, which must therefore cover most of fruit surface to avoid pathogen infection. Our objective was to optimize the efficacy of P. frequentans by maximizing fruit surface coverage and retention with the antagonist formulation by surfactant incorporation.

RESULTS

Sixteen surfactants were assessed for the management of brown rot at 3–5 different concentrations. Nine surfactants increased the droplet surface up to 2.5 times compared with water on an inert surface, with or without the presence of P. frequentans in each drop. Eight surfactants increased P. frequentans on the fruit surface, enhancing colony forming units after run off or lateral spray application uptake by 50% compared to the control without surfactants. But only some doses of sodium carboxymethyl cellulose, gelatin, Tween 20, sorbitan alkyl esters, synthetic latex, polyethylene glycol isotridecyl ether, and hydroxypropyl methylcellulose could show the same covered fruit surface after run off or lateral spray application. There were also no phytotoxic side‐effects on five different species of stone fruit.

CONCLUSIONS

The efficacy of P. frequentans dry conidia can be enhanced by optimizing the composition of the formulation with surfactants. © 2018 Society of Chemical Industry
3D‐specific absorption rate estimation from high‐intensity focused ultrasound sonications using the Green's function heat kernel
Authors: Freeman Nicholas J. , Odéen Henrik , Parker Dennis L.
Published: May 2018

Purpose

To evaluate a numerical inverse Green's function method for deriving specific absorption rates (SARs) from high‐intensity focused ultrasound (HIFU) sonications using tissue parameters (thermal conductivity, specific heat capacity, and mass density) and three‐dimensional (3D) magnetic resonance imaging (MRI) temperature measurements.

Methods

SAR estimates were evaluated using simulations and MR temperature measurements from HIFU sonications. For simulations, a “true” SAR was calculated using the hybrid angular spectrum method for ultrasound simulations. This “true” SAR was plugged into a Pennes bioheat transfer equation (PBTE) solver to provide simulated temperature maps, which were then used to calculate the SAR estimate using the presented method. Zero mean Gaussian noise, corresponding to temperature precisions between 0.1 and 2.0°C, was added to the temperature maps to simulate a variety of in vivo situations. Experimental MR temperature maps from HIFU sonications in a gelatin phantom monitored with a 3D segmented echo planar imaging MRI pulse sequence were also used. To determine the accuracy of the simulated and phantom data, we reconstructed temperature maps by plugging in the estimated SAR to the PBTE solver. In both simulations and phantom experiments, the presented method was compared to two previously published methods of determining SAR, a linear and an analytical method. The presented numerical method utilized the full 3D data simultaneously, while the two previously published methods work on a slice‐by‐slice basis.

Results

In the absence of noise, SAR distribution estimates obtained from the simulated heating profiles match closely (within 10%) to the initial true SAR distribution. The resulting temperature distributions also match closely to the corresponding initial temperature distributions (<0.2°C RMSE). In the presence of temperature measurement noise, the SAR distributions have noise amplified by the inverse convolution process, while the resulting temperature distributions still match closely to the initial “true” temperature distributions. In general, temperature RMSE was observed to be approximately 20–30% higher than the level of the added noise. By contrast, the previously published linear method is less sensitive to noise, but significantly underpredicts the SAR. The analytic method is also less sensitive to noise and matches SAR in the central plane, but greatly underpredicts in the longitudinal direction. Similar observations are made from the phantom studies. The described numerical inverse Green's function method is very fast — at least two orders of magnitude faster than the compared methods.

Conclusion

The presented numerical inverse Green's function method is computationally fast and generates temperature maps with high accuracy. This is true despite generally overestimating the true SAR and amplifying the input noise.
Technical Note: Interleaved bipolar acquisition and low‐rank reconstruction for water–fat separation in MRI
Authors: Cho JaeJin , Park HyunWook
Published: May 2018

Purpose

To acquire interleaved bipolar data and reconstruct the full data using low‐rank property for water–fat separation.

Methods

Bipolar acquisition suffers from issues related to gradient switching, the opposite gradient polarities, and other system imperfections, which prevent accurate water–fat separation. In this study, an interleaved bipolar acquisition scheme and a low‐rank reconstruction method were proposed to reduce issues from the bipolar gradients while achieving a short imaging time. The proposed interleaved bipolar acquisition scheme collects echo‐time signals from both gradient polarities; however, the sequence increases the imaging time. To reduce the imaging time, the signals were subsampled at every dimension of k‐space. The low‐rank property of the bipolar acquisition was defined and exploited to estimate the full data from the acquired subsampled data. To eliminate the bipolar issues, in the proposed method, the water–fat separation was performed separately for each gradient polarity, and the results for the positive and negative gradient polarities were combined after the water–fat separation.

Results

A phantom study and in vivo experiments were conducted on a 3T Siemens Verio system. The results for the proposed method were compared with the results of the fully sampled interleaved bipolar acquisition and the Soliman's method, which was the previous water–fat separation approach for reducing the issues of bipolar gradients and accelerating the interleaved bipolar acquisition. The proposed method provided accurate water and fat images without the issues of bipolar gradients and demonstrated a better performance compared with the results of the previous methods.

Conclusions

The water–fat separation using the bipolar acquisition has several benefits including a short echo‐spacing time. However, it suffers from bipolar‐gradient issues such as strong gradient switching, system imperfection, and eddy current effects. This study demonstrated that accurate water–fat separated images can be obtained using the proposed interleaved bipolar acquisition and low‐rank reconstruction by using the benefits of the bipolar acquisition while reducing the bipolar‐gradient issues with a short imaging time.
Impact of interpatient variability on organ dose estimates according to MIRD schema: Uncertainty and variance‐based sensitivity analysis
Authors: Zvereva Alexandra , Kamp Florian , Schlattl Helmut , Zankl Maria , Parodi Katia
Published: May 2018

Purpose

Variance‐based sensitivity analysis (SA) is described and applied to the radiation dosimetry model proposed by the Committee on Medical Internal Radiation Dose (MIRD) for the organ‐level absorbed dose calculations in nuclear medicine. The uncertainties in the dose coefficients thus calculated are also evaluated.

Methods

A Monte Carlo approach was used to compute first‐order and total‐effect SA indices, which rank the input factors according to their influence on the uncertainty in the output organ doses. These methods were applied to the radiopharmaceutical (S)‐4‐(3‐18F‐fluoropropyl)‐L‐glutamic acid (18F‐FSPG) as an example. Since 18F‐FSPG has 11 notable source regions, a 22‐dimensional model was considered here, where 11 input factors are the time‐integrated activity coefficients (TIACs) in the source regions and 11 input factors correspond to the sets of the specific absorbed fractions (SAFs) employed in the dose calculation. The SA was restricted to the foregoing 22 input factors. The distributions of the input factors were built based on TIACs of five individuals to whom the radiopharmaceutical 18F‐FSPG was administered and six anatomical models, representing two reference, two overweight, and two slim individuals. The self‐absorption SAFs were mass‐scaled to correspond to the reference organ masses.

Results

The estimated relative uncertainties were in the range 10%–30%, with a minimum and a maximum for absorbed dose coefficients for urinary bladder wall and heart wall, respectively. The applied global variance‐based SA enabled us to identify the input factors that have the highest influence on the uncertainty in the organ doses. With the applied mass‐scaling of the self‐absorption SAFs, these factors included the TIACs for absorbed dose coefficients in the source regions and the SAFs from blood as source region for absorbed dose coefficients in highly vascularized target regions. For some combinations of proximal target and source regions, the corresponding cross‐fire SAFs were found to have an impact.

Conclusion

Global variance‐based SA has been for the first time applied to the MIRD schema for internal dose calculation. Our findings suggest that uncertainties in computed organ doses can be substantially reduced by performing an accurate determination of TIACs in the source regions, accompanied by the estimation of individual source region masses along with the usage of an appropriate blood distribution in a patient's body and, in a few cases, the cross‐fire SAFs from proximal source regions.
Prostate DCE‐MRI with correction using an approximated analytical approach
Authors: Zhong Xinran , Martin Thomas , Wu Holden H. , Nayak Krishna S. , Sung Kyunghyun
Published: May 2018

Purpose

To develop and evaluate a practical

correction method for prostate dynamic contrast‐enhanced (DCE) MRI analysis.

Theory

We proposed a simple analytical

correction method using a Taylor series approximation to the steady‐state spoiled gradient echo signal equation. This approach only requires

maps and uncorrected pharmacokinetic (PK) parameters as input to estimate the corrected PK parameters.

Methods

The proposed method was evaluated using a prostate digital reference object (DRO), and 82 in vivo prostate DCE‐MRI cases. The approximated analytical correction was compared with the ground truth PK parameters in simulation, and compared with the reference numerical correction in in vivo experiments, using percentage error as the metric.

Results

The prostate DRO results showed that our approximated analytical approach provided residual error less than 0.4% for both Ktrans and ve, compared to the ground truth. This noise‐free residual error was smaller than the noise‐induced error using the reference numerical correction, which had a minimum error of 2.1+4.3% with baseline signal‐to‐noise ratio of 234.5. For the 82 in vivo cases, Ktrans and ve percentage error compared to the reference numerical correction method had a mean of 0.1% (95% central range of [0.0%, 0.2%]) across the prostate volume.

Conclusion

The approximated analytical

correction method provides comparable results with less than 0.2% error within 95% central range, compared to reference numerical

correction. The proposed method is a practical solution for

correction in prostate DCE‐MRI because of its simple implementation.
Reliability of the Animated Activity Questionnaire for assessing activity limitations of patients with hip and knee osteoarthritis
Authors: Peter W.F. , de Vet H.C.W. , Terwee C.B.
Published: May 2018

Objective

The aim of the study was to determine the internal consistency, test–retest reliability and measurement error of the Animated Activity Questionnaire (AAQ) for assessing activity limitations in hip and knee osteoarthritis (HKOA) patients.

Methods

A total of 1,177 patients, from six countries (the Netherlands, UK, France, Denmark, Italy and Spain), completed the AAQ, a questionnaire consisting of videos displaying 17 activities with 3–5 levels of performance, from which patients choose the video that best matches their own performance. Unidimensionality was assessed by means of confirmatory factor analysis (CFA), using the following fit indices: the Tucker–Lewis index (TFI) >0.95, comparative fit index (CFI) >0.95, and root mean square error of approximation (RMSEA) <0.06. Cronbach's alpha was computed. In 238 patients who completed the AAQ twice, the intra‐class correlation coefficient (ICC) was calculated for test–retest reliability. The standard error of measurement (SEM) and the smallest detectable change (SDC) were calculated as parameters of measurement error.

Results

The fit indices for unidimensionality were CFI 0.957, TLI 0.950, and RMSEA 0.144. Cronbach's alpha was 0.95. ICC for test–retest reliability was 0.93 (95% confidence interval 0.91 to 0.95), ranging from 0.85 to 0.98 across countries. SEM and SDC were 4.9 and 13.6, respectively, on a scale from 0 to 100, and ranging from 2.7 to 6.7, and from 7.5 to 18.4, respectively, across countries. The AAQ appeared to measure slightly more precisely in patients with knee problems and patients without prosthesis.

Conclusion

The AAQ seemed to be unidimensional, and showed good internal consistency and test–retest reliability. The SDC indicated that changes in scores of at least 14% indicate real improvement in activity limitations.
The associations between anthropometric measurements and left ventricular structure and function: the Echo‐SOL Study
Authors: Ponce S. , Allison M. A. , Swett K. , Cai J. , Desai A. A. , Hurwitz B. E. , Ni A. , Schneiderman N. , Shah S. J. , Spevack D. M. , Talavera G. A. , Rodriguez C. J.
Published: May 2018

Objective

The objective of this study is to determine associations between anthropometry and echocardiographic measures of cardiac structure and function in Hispanic/Latinos.

Methods

A total of 1,824 participants from ECHO‐SOL were included. We evaluated associations between echocardiographic measures of left ventricular structure and function and anthropometric measures using multivariable‐adjusted linear and logistic regression models adjusting for traditional cardiovascular risk factors.

Results

The mean age was 56 ± 0.17 years, 57% were women. The mean body mass index (BMI) was 30 ± 9.4 kg m−2, waist circumference (WC) was 100 ± 18 cm, and waist‐to‐hip ratio (WHR) was 0.93 ± 0.15. Adjusted analysis showed that 5‐unit increment in BMI and 5‐cm increase in WC was associated with 3.4 ± 0.6 and 1.05 ± 0.05 g m−2.7 (p < 0.05 for both) higher left ventricular (LV) mass index, respectively. Similarly, 0.1‐unit increment in WHR was associated with 2.0 ± 0.16 g m−2.7 higher LV mass index (p < 0.01). WHR was associated with 0.22 ± 0.08% decrease in ejection fraction (p < 0.05). Concomitantly, 5‐unit increment in BMI and WC was associated with increased odds of abnormal LV geometry (odds ratio 1.40 and 1.16, p = 0.03 and <0.01, respectively); 0.1‐unit increment in WHR was associated with increased odds of abnormal LV geometry (odds ratio 1.51, p < 0.01).

Conclusions

Among Hispanic/Latinos, higher anthropometric measures were associated with adverse cardiac structure and function.
Effect of Small‐Angle Grain Boundary on the Mechanical Properties in Direct Silicon Bonded Wafer
Authors: Wang Peng , Cui Can , Yu Xuegong , Li Zhonglan , Yang Deren
Published: May 2018

The mechanical properties of small‐angle grain boundary (GB) in direct silicon bonded wafer are investigated by dislocation motion using the Vickers micro‐indentation combined with nano‐indentation technique. The dislocation motion is thoroughly hampered at the GB, due to the large strain field (comprehensive stress as high as ≈339 MPa), which is demonstrated by the micro‐Raman spectroscopy measurement. Nano‐indentation tests directly on GB show that Young's modulus and hardness are almost identical to those in the grain. The results indicate that electrically active small‐angle GB with high stress should not be the weak point of mechanical strength in multi‐crystalline silicon.
Evolutionary Data Driven Modeling and Multi Objective Optimization of Noisy Data Set in Blast Furnace Iron Making Process
Authors: Mahanta Bashista Kumar , Chakraborti Nirupam
Published: May 2018

Data driven models are constructed for the tuyere cooling heat loss, total blast furnace gas flow, tuyere velocity, productivity, and coke rate for an operational blast furnace of an integrated steel plant by using evolutionary computation methods like bi objective genetic programming (BioGP) and evolutionary neural network (EvoNN), which serve as the objectives for their optimization. The models are used to compute the Pareto tradeoff between these conflicting objectives with the help of predator prey genetic algorithm well tasted for computing the Pareto optimality earlier. The results of optimization and the performances of these models are thoroughly analyzed and accessed and a discussion regarding these data driven models and their influence in the ironmaking process are presented. The results are also compared against a similar calculation performed with the commercial software KIMEME.
Hybrid Nanocomposite Films of Starch, Poly(vinyl alcohol) (PVA), Starch Nanocrystals (SNCs), and Montmorillonite (Na‐MMT): Structure–Properties Relationship
Authors: Naderizadeh Sara , Shakeri Alireza , Mahdavi Hossein , Nikfarjam Nasser , Taheri Qazvini Nader
Published: May 2018

Starch, as a natural, renewable, and biodegradable polysaccharide, is widely used in the food and pharmaceutical industries. However, the extreme water‐sensitivity and poor tensile strength of starch materials have limited its practical application as an engineering material. Here, the authors blended starch with PVA to improve its film formability, and then, added Na‐MMT and SNCs to the blend in order to enhance the mechanical properties. Nanofillers are used in pure and hybrid form to study the synergistic effect of these two types of nanofillers. SNCs, obtained by acidic hydrolysis of potato starch granules, have a z‐average particle size of ≈230 nm and crystallinity of 57%. Nanocomposite films, prepared via the solution casting method, are characterized by X‐ray diffraction (XRD) and tensile testing methods. XRD patterns confirmed the exfoliation dispersion of Na‐MMT in the polymer blend matrix. Additionally, the results of the tensile tests and thermogravimetric analysis (TGA) indicated that the presence of nanofillers in separate and hybrid forms in the matrix led to the improvement of the mechanical and thermal properties of nanocomposites. Finally, the findings revealed the synergistic effect of nanofillers of SNCs and Na‐MMT for improving the mechanical and thermal properties of starch/PVA blend, particularly in 3 wt% of the total filler content in 50:50 (w/w).
Load thermal inertia modeling method based on discrete‐time inertia model
Authors: Chen Pei‐Pei , Bao Yu‐Qing
Published: May 2018

Because of thermal inertia, the electric load is affected by the current temperatures as well as historical temperatures. This paper proposes a thermal inertia modeling method for the electric load to reduce forecasting error. In the proposed method, the relationship between the load and the temperature is established based on the discrete‐time inertia system model, in which the key parameters are obtained by particle swarm optimization (PSO). Test results show that the proposed method can model the thermal inertia well and improve the accuracy of electric load forecasting. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
The singularity structure of scale-invariant rank-2 Coulomb branches
Authors: Argyres Philip C. , Long Cody , Martone Mario
Published: May 2018

Abstract

We compute the spectrum of scaling dimensions of Coulomb branch operators in 4d rank-2

$$ \mathcal{N}=2 $$

N
=
2

superconformal field theories. Only a finite rational set of scaling dimensions is allowed. It is determined by using information about the global topology of the locus of metric singularities on the Coulomb branch, the special Kähler geometry near those singularities, and electric-magnetic duality monodromies along orbits of the U(1)
R
symmetry. A set of novel topological and geometric results are developed which promise to be useful for the study and classification of Coulomb branch geometries at all ranks.
α′-corrected black holes in String Theory
Authors: Cano Pablo A. , Meessen Patrick , Ortín Tomás , Ramírez Pedro F.
Published: May 2018

Abstract

We consider the well-known solution of the Heterotic Superstring effective action to zeroth order in α
′ that describes the intersection of a fundamental string with momentum and a solitonic 5-brane and which gives a 3-charge, static, extremal, supersymmetric black hole in 5 dimensions upon dimensional reduction on T5. We compute explicitly the first-order in α
′ corrections to this solution, including SU(2) Yang-Mills fields which can be used to cancel some of these corrections and we study the main properties of this α
′-corrected solution: supersymmetry, values of the near-horizon and asymptotic charges, behavior under α
′-corrected T-duality, value of the entropy (using Wald formula directly in 10 dimensions), existence of small black holes etc. The value obtained for the entropy agrees, within the limits of approximation, with that obtained by microscopic methods. The α
′ corrections coming from Wald’s formula prove crucial for this result.
Ventilator Bundle Compliance and Risk of Ventilator-Associated Events
Authors: Harris Bryan D. , Thomas Gale A. , Greene Matthew H. , Spires Steven S. , Talbot Thomas R.
Published: May 2018

OBJECTIVE

Ventilator bundles encompass practices that reduce the risk of ventilator complications, including ventilator-associated pneumonia. The impact of ventilator bundles on the risk of developing ventilator-associated events (VAEs) is unknown. We sought to determine whether decreased compliance to the ventilator bundle increases the risk for VAE development.

DESIGN

Nested case-control study.

SETTING

This study was conducted at 6 adult intensive care units at an academic tertiary-care center in Tennessee.

PATIENTS

In total, 273 patients with VAEs were randomly matched in a 1:4 ratio to controls by mechanical ventilation duration and ICU type.

METHODS

Controls were selected from the primary study population at risk for a VAE after being mechanically ventilated for the same number of days as a specified case. Using conditional logistic regression analysis, overall cumulative compliance, and compliance with individual components of the bundle in the 3 and 7 days prior to VAE development (or the control match day) were examined.

RESULTS

Overall bundle compliance at 3 days (odds ratio [OR], 1.15; P=.34) and 7 days prior to VAE diagnosis (OR, 0.96; P=.83) were not associated with VAE development. This finding did not change when limiting the outcome to infection-related ventilator-associated complications (IVACs) and after adjusting for age and gender. In the examination of compliance with specific bundle components increased compliance with chlorhexidine oral care was associated with increased risk of VAE development in all analyses.

CONCLUSIONS

Ventilator bundle compliance was not associated with a reduced risk for VAEs. Higher compliance with chlorhexidine oral care was associated with a greater risk for VAE development.

Infect Control Hosp Epidemiol 2018;39:637–643