bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of transabdominal and transvaginal sonography in the diagnosis of placenta previa
Authors: Petpichetchian Chusana , Pranpanus Savitree , Suntharasaj Thitima , Kor‐anantakul Ounjai , Hanprasertpong Tharangrut
Published: April 2018

Purpose

To compare the accuracies of transabdominal sonography (TAS) and transvaginal sonography (TVS) in the diagnosis of placenta previa.

Methods

A prospective, cross‐sectional study was conducted at a university hospital. Both TAS and TVS were performed on 81 pregnant women with a suspicion of placenta previa in the third trimester. The final diagnosis was confirmed at delivery. The agreement between the two ultrasound methods and the parameters of each method were calculated.

Results

Fifty‐eight percent of the women had a placenta previa. The sensitivities of TAS and TVS were 86% (95% CI 78‐94%) and 95% (95% CI 91‐100%), respectively (p= 0.2). The specificity of both methods was 93% (95 CI 88‐99%), and the overall accuracies of TAS and TVS were 89% (95% CI 82‐96%) and 94% (95% CI 89‐100%), respectively. When TAS was followed by TVS, 23% of the previous diagnoses were changed. The agreement between both methods was good (Kappa value = 0.7, 95%CI 0.55‐0.86).

Conclusions

For the diagnosis of placenta previa, TAS showed a high sensitivity and specificity, which were comparable to those of TVS
Integrating dynamic contrast‐enhanced magnetic resonance imaging and diffusion kurtosis imaging for neoadjuvant chemotherapy assessment of nasopharyngeal carcinoma
Authors: Zheng Dechun , Lai Guojing , Chen Ying , Yue Qiuyuan , Liu Xiangyi , Chen Xiaodan , Chen Weibo , Chan Queenie , Chen Yunbin
Published: April 2018

Background

Since neoadjuvant chemotherapy (NAC) has proven a benefit for locally advanced nasopharyngeal carcinoma (NPC), early response evaluation after chemotherapy is important to implement individualized therapy for NPC in the era of precision medicine.

Purpose

To determine the combined and independent contribution between dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) and diffusion kurtosis imaging (DKI) in the early monitoring of NAC response for NPC.

Study Type

Prospective.

Population

Fifty‐three locally advanced NPC patients.

Field Strength/Sequence

Four examinations before and at 4, 20, and 40 days after NAC initiation were performed at 3T MRI including DCE‐MRI and DKI (b values = 0, 500, 1000, 1500 s/mm2).

Assessment

DCE‐MRI parameters (Ktrans [the volume transfer constant of Gd‐DTPA], kep [rate constant], νe [the extracellular volume fraction of the imaged tissue], and νp [the blood volume fraction]) and DKI parameters (Dapp [apparent diffusion for non‐Gaussian distribution] and Kapp [apparent kurtosis coefficient]) were analyzed using dedicated software.

Statistical Tests

MRI parameters and their corresponding changes were compared between responders and nonresponders after one or two NAC cycles treatment using independent‐samples Student's t‐test or Mann–Whitney U‐test depending on the normality contribution test and then followed by logistic regression and receiver operating characteristic curve (ROC) analyses.

Results

The responder group (RG) patients presented significantly higher mean Ktrans and Dapp values at baseline and larger
, Δvp(0‐4), and ΔDapp(0‐4) values after either one or two NAC cycles compared with the nonresponder group (NRG) patients (all P < 0.05). ROC analyses demonstrated the higher diagnostic accuracy of combined DCE‐MRI and DKI model to distinguish nonresponders from responders after two NAC cycles than using DCE‐MRI (0.987 vs. 0.872, P = 0.033) or DKI (0.987 vs. 0.898, P = 0.047) alone.

Data Conclusion

Combined DCE‐MRI and DKI models had higher diagnostic accuracy for NAC assessment compared with either model used independently.

Level of Evidence: 2

Technical Efficacy: Stage 2

J. Magn. Reson. Imaging 2018;47:1208–1216.
Climatology of sea breezes along the Red Sea coast of Saudi Arabia
Authors: Khan Basit , Abualnaja Yasser , Al‐Subhi Abdullah M. , Nellayaputhenpeedika Mohammedali , Nellikkattu Thody Manoj , Sturman Andrew P.
Published: April 2018

Long‐term near‐surface observations from five coastal stations, high‐resolution model data from Modern Era Retrospective‐Analysis for Research and Applications (MERRA) and high‐resolution daily sea surface temperature (SST) from National Ocean and Atmospheric Administration (NOAA) are used to investigate the climatology of sea breezes over the eastern side of the Red Sea region. Results show existence of separate sea breeze systems along different segments of the Red Sea coastline. Based on the physical character and synoptic influences, sea breezes in the Red Sea are broadly divided into three regions: the north and the middle Red Sea (NMRS), the Red Sea convergence zone (RSCZ) and the southern Red Sea (SRS) regions. On average, sea breezes developed on 67% of days of the 10‐year study period. Although sea breezes occur almost all year, this mesoscale phenomenon is most frequent from May to October (78% of the total sea breeze days). The sea breeze frequency increases from north to south (equatorwards), and sea breeze characteristics appear to vary both temporally and spatially. In addition to land–sea thermal differential, coastline shape, latitude and topography, the prevailing northwesterly at NMRS region, the convergence of northwesterly and southeasterly wind system at RSCZ region and the northeast and southwest monsoon at SRS region play an important role in defining the sea breeze characteristics over the Red Sea.
Atmospheric circulation patterns associated with persistent wet‐freezing events over southern China
Authors: Liao Zhen , Zhai Panmao , Chen Yang , Lu Hong
Published: April 2018

Persistent wet‐freezing events (PWFEs), a typical type of compound extremes, combine adverse effects from both its precipitation and temperature components, thereby posing great threats to human society and ecosystem. Atmospheric circulation patterns that govern the occurrence and persistence of PWFEs over southern China are identified and classified, based on cases during 1980–2010. There are two dominating types of large‐scale atmospheric circulation patterns responsible for PWFEs: a single blocking high type and a double blocking high type. The single blocking high type tends to occur under positive Arctic Oscillation (AO) phase, characteristics of a long‐lived blocking high over the Lake Baikal in the middle troposphere favouring lower‐level cold air masses penetrate southwards along a northeast–southwest route. Likewise, abundant water vapour advances northwards from the Bay of Bengal and the South China Sea, meeting cold air masses over southern China under the upper‐level divergence caused by the intensified upper‐level subtropical jet which prevails on top of the western Qinghai–Tibet Plateau. Locally, a stable temperature inversion structure is anchored in the lower troposphere. The double blocking high type features blocking highs over the Ural Mountains and the Sea of Okhotsk, along with an intensified trough between them. The upper‐level subtropical jet over mid‐latitude East Asia strengthens, providing divergence fields at upper troposphere. Low‐level cold air masses move southwards from the Lake Baikal along a north route, converging with the water vapour transported from the Bay of Bengal to southern China by a low‐level southwesterly jet. By contrast, the inversion layer is absent atop the region experiencing double blocking PWFEs. Regardless of event types, the duration of PWFEs is dedicated by Rossby wave energy dispersion through its role in maintaining blocking patterns during the PWFEs.
Impact of nitrogen availability upon the electron requirement for carbon fixation in Australian coastal phytoplankton communities
Authors: Hughes David J. , Varkey Deepa , Doblin Martina A. , Ingleton Tim , Mcinnes Allison , Ralph Peter J. , van Dongen‐Vogels Virginie , Suggett David J.
Published: April 2018

Nitrogen (N) availability affects phytoplankton photosynthetic performance and regulates marine primary production (MPP) across the global coast and oceans. Bio‐optical tools including Fast Repetition Rate fluorometry (FRRf) are particularly well suited to examine MPP variability in coastal regions subjected to dynamic spatio‐temporal fluctuations in nutrient availability. FRRf determines photosynthesis as an electron transport rate through Photosystem II (ETRPSII), requiring knowledge of an additional parameter, the electron requirement for carbon fixation (KC), to retrieve rates of CO2‐fixation. KC strongly depends upon environmental conditions regulating photosynthesis, yet the importance of N‐availability to this parameter has not been examined. Here, we use nutrient bioassays to isolate how N (relative to other macronutrients P, Si) regulates KC of phytoplankton communities from the Australian coast during summer, when N‐availability is often highly variable. KC consistently responded to N‐amendment, exhibiting up to a threefold reduction and hence an apparent increase in the efficiency with which electrons were used to drive C‐fixation. However, the process driving this consistent reduction was dependent upon initial conditions. When diatoms dominated assemblages and N was undetectable (e.g., post bloom), KC decreased predominantly via a physiological adjustment of the existing community to N‐amendment. Conversely, for mixed assemblages, N‐addition achieved a similar reduction in KC through a change in community structure toward diatom domination. We generate new understanding and parameterization of KC that is particularly critical to advance how FRRf can be applied to examine C‐uptake throughout the global ocean where nitrogen availability is highly variable and thus frequently limits primary productivity.
Dynamic processing of DOM: Insight from exometabolomics, fluorescence spectroscopy, and mass spectrometry
Authors: Smith H. J. , Tigges M. , D'Andrilli J. , Parker A. , Bothner B. , Foreman C. M.
Published: April 2018

Dissolved organic matter (DOM) in freshwater environments is an important source of organic carbon, supporting bacterial respiration. Frozen environments cover vast expanses of our planet, with glaciers and ice‐sheets storing upwards of 6 petagrams of organic carbon. It is generally believed that DOM liberated from ice stimulates downstream environments. If true, glacial DOM is an important component of global carbon cycling. However, coupling the release of DOM to microbial activity is challenging due to the molecular complexity of DOM and the metabolic connectivity within microbial communities. Using a single environmentally relevant organism, we demonstrate that processing of compositionally diverse DOM occurs, but, even though glacially derived DOM is chemically labile, it is unable to support sustained respiration. In view of projected changes in glacier DOM export, these findings imply that biogeochemical impacts on downstream environments will depend on the reactivity and heterogeneity of liberated DOM, as well as the timescale.
Involvement of a host Cathepsin L in symbiont‐induced cell death
Authors: Peyer Suzanne M. , Kremer Natacha , McFall‐Ngai Margaret J.
Published: April 2018

The cathepsin L gene of the host squid, Euprymna scolopes, is upregulated during the first hours of colonization by the symbiont Vibrio fischeri. At this time, the symbiotic organ begins cell death‐mediated morphogenesis in tissues functional only at the onset of symbiosis. The goal of this study was to determine whether Cathepsin L, a cysteine protease associated with apoptosis in other animals, plays a critical role in symbiont‐induced cell death in the host squid. Sequence analysis and biochemical characterization demonstrated that the protein has key residues and domains essential for Cathepsin L function and that it is active within the pH range typical of these proteases. With in situ hybridization and immunocytochemistry, we localized the transcript and protein, respectively, to cells interacting with V. fischeri. Activity of the protein occurred along the path of symbiont colonization. A specific Cathepsin L, nonspecific cysteine protease, and caspase inhibitor each independently attenuated activity and cell death to varying degrees. In addition, a specific antibody decreased cell death by ~50%. Together these data provide evidence that Cathepsin L is a critical component in the symbiont‐induced cell death that transforms the host tissues from a colonization morphology to one that promotes the mature association.
Existence of solution for a nonlinear model of thermo‐visco‐plasticity
Authors: Bartczak Leszek , Owczarek Sebastian
Published: April 2018

We study a thermodynamically consistent model describing phenomena in a visco‐plastic metal subjected to temperature changes. We complete the model with the mixed boundary condition on displacement and stress and Neumann‐type condition for temperature. The main result is an existence of solutions.
Volume integral equations of the scattering problem of poroelasticity and their properties
Authors: Kanaun Sergey , Levin Valery , Markov Mikhail
Published: April 2018

Scattering of monochromatic waves on an isolated inhomogeneity (inclusion) in an infinite poroelastic medium is considered. Wave propagation in the medium and the inclusion are described by Biot's equations of poroelasticity. The problem is reduced to 3D‐integro‐differential equations for displacement and pressure fields in the region occupied by the inclusion. Properties of the integral operators in these equations are studied. Discontinuities of the fields on the inclusion boundary are indicated. The case of a thin inclusion with low permeability is considered. The corresponding scattering problem is reduced to a 2D integral equation on the middle surface of the inclusion. The unknown function in this equation is the pressure jump in the transverse direction to the inclusion middle surface. An inclusion with a thin layer of low permeability on its interface is considered. The appropriate boundary conditions on the inclusion interface are pointed out. Methods of numerical solution of the volume integral equations of the scattering problems of poroelasticity are discussed.
Exact solutions via invariant approach for Black‐Scholes model with time‐dependent parameters
Authors: Naz Rehana , Johnpillai Andrew Gratien
Published: April 2018

We analyze the Black‐Scholes model with time‐dependent parameters, and it is governed by a parabolic partial differential equation (PDE). First, we compute the Lie symmetries of the Black‐Scholes model with time‐dependent parameters. It admits 6 plus infinite many Lie symmetries, and thus, it can be reduced to the classical heat equation. We use the invariant criteria for a scalar linear (1+1) parabolic PDE and obtain 2 sets of equivalence transformations. With the aid of these equivalence transformations, the Black‐Scholes model with time‐dependent parameters transforms to the classical heat equation. Moreover, the functional forms of the time‐dependent parameters in the PDE are determined via this method. Then we use the equivalence transformations and known solutions of the heat equation to establish a number of exact solutions for the Black‐Scholes model with time‐dependent parameters.
Recurrence quantification analysis of radiologists' scanpaths when interpreting mammograms
Authors: Gandomkar Ziba , Tay Kevin , Brennan Patrick C. , Mello‐Thoms Claudia
Published: April 2018

Purpose

The purpose of this study was to Propose a classifier based on recurrence quantification analysis (RQA) metrics for distinguishing experts' scanpaths from those of less‐experienced readers and to explore the association of spatiotemporal dynamics of the mammographic scanpaths with the characteristics of cases and radiologists usingRQAmetrics.

Materials and methods

Eye movements were recorded from eight radiologists (two cohorts: four experienced and four less‐experienced) while reading 120 mammograms (59 cancer, 61 normal). TenRQAmeasures were extracted for each recorded scanpath. The measures described the temporal distribution of recurrent fixations as well as laminar and deterministic eye movements. Recurrent fixations are fixations that are located close to a previously fixated point in a scanpath. Deterministic eye movements represent looking back and forth between two locations, while laminar eye movements indicate detailed scanning of an area with consecutive fixations. TheRQAmetrics along with six conventional eye‐tracking parameters were used to construct a classifier for distinguishing experts' scanpaths from those of less‐experienced readers. Leave‐one‐out cross validation was used for evaluating the classifier. For each reader cohort, theANOVAanalysis was done to study the relationship ofRQAmeasures with breast density, case pathology, readers' expertise, and readers' decisions on the case. The proportions of laminar and deterministic movements involved fixations in the location of lesions were also compared for two reader cohorts using two proportion z‐tests.

Results

AllRQAmeasures differed significantly between scanpaths of experienced readers and those of less‐experienced readers. The classifier achieved an area under the receiver operating characteristic curve of 0.89 (0.87–0.91) for detecting experts' scanpaths. Proportionately more refixations and laminar and deterministic sequences were in the location of the lesion for the experienced cohort compared to the less‐experienced cohort (allP‐values < 0.001). Eight and fourRQAmeasures differed between normal and cancer cases for the experienced and less experienced readers, respectively. None of metrics differed between fatty and dense breasts for the less experienced readers, while two measures resulted into a significant difference for the experienced readers. For experts, six measures differed significantly between true negatives and false positives and nine were significantly different between true positives and false negatives. For the less‐experienced cohort, the corresponding figures were seven and one measures, respectively.

Conclusion

TheRQAmeasures can quantify the differences among experienced and less experienced radiologists. They also capture differences among experts' scanpaths related to case pathology and radiologists' decisions on the case.
Effect of radiation protraction in hypofractionated radiotherapy
Authors: Kuperman Vadim Y.
Published: April 2018

Purpose

To evaluate how protracted delivery of radiation affects radiobiological properties of hypofractionated radiotherapy.

Methods

The utilized approach is based on the concept of biologically effective dose (BED). The linear‐quadratic model replete with a protraction factor is used to describe changes in biologically effective dose in normal tissue (BEDnt) caused by varying number of fractions under the condition of fixed BED in the treatment target (BEDtar). In the derivations, we study the influence of fraction time (T) and associated repair of sublethal damage of irradiated cells on BEDnt.

Results

We have analytically derived conditions under which hypofractionation lowers BEDnt, in a parallel or serial organ at risk (OAR) in the presence of radiation protraction, as compared to standard fractionation. In the considered examples, maximum value of BEDnt in the spinal cord decreased with decreasing number of fraction when T was relatively short (e.g., T = 5 min). In contrast, in the case of long fraction times of 30 and 45 min, maximum BEDnt in the cord increased with decreasing number of fractions. In the case of lung cancer, the average BEDnt in the lung increased with decreasing number of fractions. The maximum increase in BEDnt varied between 4% for T = 1 min and 19% for T = 22 min.

Conclusion

In the case when repair of sublethal damage occurs faster in the target than in the affected OAR, shortening fraction time helps lower BEDnt in hypofractionated regimen as compared to standard fractionation. In contrast, in the case when repair rate is higher in the OAR than in the target, long fraction times can be radiobiologically beneficial for hypofractionated radiotherapy. Consequently, comparison of different fractionation schemes should take into account both repair rates in the target and OAR, and fraction time.
The relationships among aberrant salience, reward motivation, and reward sensitivity
Authors: Neumann Suzanne R. , Linscott Richard J.
Published: April 2018

Objectives

Change in reward processing and motivation may mediate the relationship between dopaminergic dysregulation and positive symptoms of schizophrenia. We sought to investigate the measurement of aberrant salience and its relationship with behavioural measures of reward and motivation.

Methods

Participants (n = 82) completed measures of aberrant salience (Aberrant Salience Inventory and Salience Attribution Task), motivation (Effort Expenditure for Rewards Task), and reinforcer sensitivity (Stimulus Chase Task). Hypotheses were tested using correlation and generalised linear modelling.

Results

Results indicated no relationship between aberrant salience measures. The Aberrant Salience Inventory was positively related to effort expenditure for lower less likely rewards and predicted the use of probability alone in decision‐making. The only significant relationship between reward and motivation was a positive relationship between gain sensitivity and motivated behaviour for higher more likely rewards.

Conclusions

Although some support for a relationship between measures of reward motivation and aberrant salience were found, there was no evidence that the aberrant salience measures had concurrent validity. Our results suggest caution is warranted when interpreting measures of aberrant salience.
J(77Se,1H) and J(77Se,13C) couplings of seleno‐carbohydrates obtained by 77Se satellite 1D 13C spectroscopy and 77Se selective HR‐HMBC spectroscopy
Authors: Uzawa Jun , Shimabukuro Junpei , Suzuki Tatsuya , Imamura Akihiro , Ishida Hideharu , Ando Hiromune , Yamaguchi Yoshiki
Published: April 2018

Seleno‐carbohydrates are those in which the oxygen of the glycosidic bond or the hydroxyl group is artificially replaced with selenium. This substitution changes 1H and 13C chemical shifts and produces spin coupling constants involving 77Se. Coupling constants, such as 2‐3J(77Se, 1H), are likely to be useful for conformational analyses of glycans because such couplings are never observed in natural glycans. Several papers have discussed the relationship between 2‐3J(77Se, 1H) and conformation; however, only few reports describe 1‐3J(77Se, 13C), which could also be useful. Here, we obtain 77Se coupling constants of seleno‐carbohydrates from 77Se‐selective HR‐HMBC and 77Se satellites in 1D 13C spectra and examine their conformations using the Newman projection scheme.
Regulation of the sperm‐to‐oocyte transition in Caenorhabditis briggsae hermaphrodites by the Cbr‐met‐2 and Cbr‐fem‐3 genes
Authors: Berenson Aaron L. , Baird Scott E.
Published: April 2018

In Caenorhabditis briggsae hermaphrodites, spermatogenesis begins in the L4 larval stage and persists into early adulthood. Oogenesis begins after spermatogenesis; the sperm‐to‐oocyte transition is irreversible. The timing of this transition is believed to have evolved in response to selection to maximize the intrinsic growth rate. Sperm‐to‐oocyte transitions occurred early in Cbr‐met‐2 and Cbr‐fem‐3 mutants. These early transitions resulted in reduced brood sizes, but had little or no impact on the intrinsic growth rate. In Cbr‐met‐2; Cbr‐fem‐3 doubly mutant hermaphrodites, the transition to oogenesis occurred even earlier and brood size was further reduced, indicating that Cbr‐met‐2 and Cbr‐fem‐3 regulate the sperm‐to‐oocyte transition through separate pathways. Mutations in Cbr‐met‐2 also resulted in an increase in the frequency of males in mutant populations. These increased male frequencies were not caused by increased rates of X nondisjunction during oogenesis in mutant hermaphrodites. Rather, increases in the rates of outcrossing in mutant populations likely were an indirect effect of reduced brood sizes derived from self‐fertilization. Based on these observations, it is possible that the timing of the sperm‐to‐oocyte transition in C. briggsae evolved in response to sexual selection on hermaphrodites to limit rates of outcrossing. Mutations in the orthologous Caenorhabditis elegans gene, Cel‐met‐2, did not impact the timing of the sperm‐to‐oocyte transition, consistent with the independent evolution of hermaphroditic reproduction in these species. Although brood sizes were reduced in Cel‐met‐2 mutant strains, increased male frequencies were not observed. Cbr‐ and Cel‐met‐2 mutations also differed in terms of germline mortality, observed in C. elegans, but not in C. briggsae.
Stability analysis of shotcrete supported crown of NATM tunnels with discontinuity layout optimization
Authors: Zhang Yiming , Zhuang Xiaoying , Lackner Roman
Published: April 2018

For tunnel constructed by New Austrian Tunnelling Method, the crown is the upper part of tunnel section, constructed during excavation process and supported by shotcrete. The stability of the crown has great influence on the safety of tunnel itself and the buildings above, which correlates, among others, with geometrical setup of tunnel and material properties of shotcrete and soil/rock. In this paper, aiming at analyzing the stability of shotcrete supported crown, a recently presented numerical method discontinuity layout optimization is adopted, which introduces a great amount of potential discontinuities cross over one another and provides a wide search space for efficient upper limit analysis. In the analysis, a well‐established hydration model of cementitious material is implemented for accounting the hydration of shotcrete. Then assumptions based on convergence‐confinement method are used for accounting the 3‐dimensional effect in 2‐dimensional analysis, finally providing time‐space–dependent assessments of stability of shotcrete supported crown.
Quantitative susceptibility mapping and 23Na imaging‐based in vitro characterization of blood clotting kinetics
Authors: Schneider Till M. , Nagel Armin M. , Zorn Markus , Wetscherek Andreas , Bendszus Martin , Ladd Mark E. , Straub Sina
Published: April 2018

Blood clotting is a fundamental biochemical process in post‐hemorrhagic hemostasis. Although the varying appearance of coagulating blood in T1‐ and T2‐weighted images is widely used to qualitatively determine bleeding age, the technique permits only a rough discrimination of coagulation stages, and it remains difficult to distinguish acute and chronic hemorrhagic stages because of low T1‐ and T2‐weighted signal intensities in both instances. To investigate new biomedical parameters for magnetic resonance imaging‐based characterization of blood clotting kinetics, sodium imaging and quantitative susceptibility mapping (QSM) were compared with conventional T1‐ and T2‐weighted imaging, as well as with biochemical hemolysis parameters. For this purpose, a blood‐filled spherical agar phantom was investigated daily for 14 days, as well as after 24 days at 7 T after initial preparation with fresh blood. T1‐ and T2‐weighted sequences, a three‐dimensional (3D) gradient echo sequence and a density‐adapted 3D radial projection reconstruction pulse sequence for 23Na imaging were applied. For hemolysis estimations, free hemoglobin and free potassium concentrations were measured photometrically and with the direct ion‐selective electrode method, respectively, in separate heparinized whole‐blood samples along the same timeline. Initial mean susceptibility was low (0.154 ± 0.020 ppm) and increased steadily during the course of coagulation to reach up to 0.570 ± 0.165 ppm. The highest total sodium (NaT) values (1.02 ± 0.06 arbitrary units) in the clot were observed initially, dropped to 0.69 ± 0.13 arbitrary units after one day and increased again to initial values. Compartmentalized sodium (NaS) showed a similar signal evolution, and the NaS/NaT ratio steadily increased over clot evolution. QSM depicts clot evolution in vitro as a process associated with hemoglobin accumulation and transformation, and enables the differentiation of the acute and chronic coagulation stages. Sodium imaging visualizes clotting independent of susceptibility and seems to correspond to clot integrity. A combination of QSM and sodium imaging may enhance the characterization of hemorrhage.
Heaviside projection–based aggregation in stress‐constrained topology optimization
Authors: Wang Cunfu , Qian Xiaoping
Published: April 2018

The paper introduces an approach to stress‐constrained topology optimization through Heaviside projection–based constraint aggregation. The aggregation is calculated by integrating Heaviside projected local stresses over the design domain, and then, it is normalized over the total material volume. Effectively, the normalized integral measures the volume fraction of the material that has violated the stress constraint. Hence, with the Heaviside aggregated constraint, we can remove the stress failed material from the final design by constraining the integral to a threshold value near zero. An adaptive strategy is developed to select the threshold value for ensuring that the optimized design is conservative. By adding a stress penalty factor to the integrand, the Heaviside aggregated constraint can further penalize high stresses and becomes more stable and less sensitive to the selection of the threshold value. Our two‐dimensional and three‐dimensional numerical experiments demonstrate that the single Heaviside aggregated stress constraint can efficiently control the local stress level. Compared with the traditional approaches based on the Kreisselmeier‐Steinhauser and p‐norm aggregations, the Heaviside aggregation–based single constraint can substantially reduce computational cost on sensitivity analysis. These advantages make it possible to apply the proposed approach to large‐scale stress‐constrained problems.
Eigenvalue topology optimization via efficient multilevel solution of the frequency response
Authors: Ferrari Federico , Lazarov Boyan S. , Sigmund Ole
Published: April 2018

The article presents an efficient solution method for structural topology optimization aimed at maximizing the fundamental frequency of vibration. Nowadays, this is still a challenging problem mainly because of the high computational cost required by spectral analyses. The proposed method relies on replacing the eigenvalue problem with a frequency response one, which can be tuned and efficiently solved by a multilevel procedure. Connections of the method with multigrid eigenvalue solvers are discussed in details. Several applications demonstrating more than 90% savings of the computational time are presented as well.
A note on the sufficiency of the maximum principle for infinite horizon optimal control problems
Authors: de Oliveira Valeriano Antunes , Silva Geraldo Nunes
Published: April 2018

This work is devoted to introduce a new sufficient optimality condition for infinite horizon optimal control problems. It is shown that normal extremal processes are optimal under this new condition, termed as maximum‐principle‐pseudo‐invexity. Such a condition is the most general possible in the sense that problems in which every normal extremal process is optimal are necessarily maximum‐principle‐pseudo‐invex.
Finite‐time convergence results in robust model predictive control
Authors: Anderson A. , González A.H. , Ferramosca A. , Kofman E.
Published: April 2018

Robust asymptotic stability (asymptotic attractivity and ϵ‐δ stability) of equilibrium regions under robust model predictive control (MPC) strategies was extensively studied in the last decades making use of Lyapunov theory in most cases. However, in spite of its potential application benefits, the problem of finite‐time convergence under fixed prediction horizon has not received, with some few exceptions, much attention in the literature. Considering the importance in several applications of having finite‐time convergence results in the context of fixed horizon MPC controllers and the lack of studies on this matter, this work presents a new set‐based robust MPC (RMPC) for which, in addition to traditional stability guarantees, finite‐time convergence to a target set is proved, and moreover, an upper bound on the time necessary to reach that set is provided. It is remarkable that the results apply to general nonlinear systems and only require some weak assumptions on the model, cost function, and target set.
A phase 1 study of cabozantinib in children and adolescents with recurrent or refractory solid tumors, including CNS tumors: Trial ADVL1211, a report from the Children's Oncology Group
Authors: Chuk Meredith K. , Widemann Brigitte C. , Minard Charles G. , Liu Xiaowei , Kim AeRang , Bernhardt Melanie Brooke , Kudgus Rachel A. , Reid Joel M. , Voss Stephan D. , Blaney Susan , Fox Elizabeth , Weigel Brenda J.
Published: April 2018

Background

We conducted a phase 1 trial to determine the maximum tolerated dose (MTD), toxicity profile, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary activity of cabozantinib in children with refractory or relapsed solid tumors.

Methods

Patients received cabozantinib tablets on a continuous dosing schedule in a rolling‐six escalating phase 1 trial design. PK and PD studies were performed.

Results

Forty‐one patients, median (range) age 13 (4–18) years, received cabozantinib to achieve a weekly cumulative dose equivalent to 30 (n = 6), 40 (n = 23). or 55 (n = 12) mg/m2/day. At 40 mg/m2/d, dose‐limiting toxicities (DLTs) were palmar‐plantar erythrodysesthesia syndrome, mucositis, and elevated alanine aminotransferase, lipase, and bilirubin. At 55 mg/m2/d, hypertension, reversible posterior leukoencephalopathy syndrome, headache, fatigue, and proteinuria were DLTs. Frequent non‐DLTs included diarrhea, hypothyroidism, fatigue, nausea, vomiting, elevated hepatic transaminases, and proteinuria. In subsequent cycles, DLTs occurred at all dose levels. Across all dose levels, the steady‐state exposure and peak cabozantinib concentrations were similar. Four patients experienced a confirmed partial response: medullary thyroid cancer (MTC; n = 2), Wilms tumor, and clear cell sarcoma. Stable disease (>6 cycles) was seen in seven patients (MTC [n = 2], Ewing sarcoma, synovial sarcoma, alveolar soft part sarcoma, paraganglioma, and ependymoma).

Conclusions

A protocol‐defined MTD was not reached; DLTs and dose reductions for toxicity occurred in the first and subsequent cycles at all dose levels. Based on the toxicity profile, pharmacokinetics, and responses, the recommended dose of cabozantinib in pediatric patients with refractory solid tumors is 40 mg/m2/day. A phase 2 study of cabozantinib is being conducted.
Mobile health intervention for youth with sickle cell disease: Impact on adherence, disease knowledge, and quality of life
Authors: Anderson Lindsay M. , Leonard Sarah , Jonassaint Jude , Lunyera Joseph , Bonner Melanie , Shah Nirmish
Published: April 2018

Background

Adherence to illness self‐management among youth with sickle cell disease (SCD) positively impacts health outcomes and decreases overall healthcare costs. Despite this, children with SCD face several barriers to adherence, with adherence rates that remain moderate to low. The current feasibility study examined the Intensive Training Program (ITP), a mobile health (mHealth) intervention for youth with SCD designed to promote disease knowledge, adherence, and patient‐provider communication.

Procedure

Youth with SCD prescribed hydroxyurea between ages 7–18 completed baseline disease knowledge and psychosocial assessments and then were provided with the ITP app. Youth participated in the 90‐day ITP, during which they completed three education modules, tracked adherence through daily self‐recorded videos on the app, and received video messages from providers. Participants completed poststudy knowledge, psychosocial, and feasibility questionnaires. Medication possession ratio (MPR) was obtained via pharmacy‐refill rates.

Results

Thirty‐two youths (mean age = 13.0 years) participated, with an average adherence tracking rate of 0.6 (standard deviation = 0.34). All participants demonstrated increased MPR (0.57–0.74, P < 0.001, d = 0.75) and disease knowledge (59.6–88.6%, P < 0.001). There was variable engagement in the ITP; completers demonstrated significantly better SCD‐related functioning (P < 0.05), higher parent‐reported treatment functioning (P < 0.05), and lower pain impact than noncompleters of the ITP (P < 0.05).

Conclusions

Results support the ITP can feasibly be implemented to promote adherence among youth with SCD. All participants demonstrated increased adherence and disease knowledge. However, there was variable engagement and only intervention completers showed improvements in psychosocial outcomes. Further research is needed to evaluate long‐term outcomes and ways to promote engagement in mHealth interventions among the youth.
High‐dose chemotherapy with autologous stem cell transplantation spares re‐irradiation for recurrent intracranial germinoma
Authors: Kubota Hirohito , Umeda Katsutsugu , Kagehiro Kouzuki , Tanaka Kuniaki , Daifu Tomoo , Hamabata Takayuki , Nodomi Seishiro , Kato Itaru , Hiramatsu Hidefumi , Arakawa Yoshiki , Mizowaki Takashi , Adachi Souichi
Published: April 2018

The clinical outcome of high‐dose chemotherapy (HDC) with autologous stem cell transplantation was retrospectively analyzed in six patients with recurrent intracranial germinoma. Prior to HDC, all patients achieved complete remission after platinum and ifosfamide‐based chemotherapy. A melphalan‐based conditioning regimen was administered in either a single cycle or multiple sequential cycles. Five of the six patients are alive and free from disease, with a median survival of 65 months, among which four patients avoided re‐irradiation. In a significant proportion of patients, recurrent intracranial germinoma is curable by HDC without re‐irradiation, provided that the disease remains sensitive to salvage chemotherapy.
β‐Ga2O3/p‐Type 4H‐SiC Heterojunction Diodes and Applications to Deep‐UV Photodiodes
Authors: Nakagomi Shinji , Sakai Toshihide , Kikuchi Kentaro , Kokubun Yoshihiro
Published: April 2018

Here, pn heterojunction diodes based on β‐Ga2O3/p‐type 4H‐SiC structures are fabricated. The current–voltage characteristics of the diodes are measured in the temperature range from 23 to 500 °C. These diodes exhibit good rectification properties and stability under high temperatures. The rectification ratios exceed 1000 even at 500 °C. Deep‐ultraviolet (deep‐UV) photodiodes are fabricated on the basis of heterojunctions having various β‐Ga2O3 thicknesses, which present the maximum responsivity at 250–260 nm and respond to UV pulses as short as ≈30 μs in real time.
A comparative study of memory‐type control charts based on robust scale estimators
Authors: Song Zhi , Liu Yanchun , Li Zhonghua , Zhang Jiujun
Published: April 2018

Exponential weighted moving average and cumulative sum (CUSUM) control charts are well‐known tool for their effectiveness in detecting small and moderate changes in the process parameters. To detect both large and small shifts, a new control structure is often recommended, named as combined Shewhart‐CUSUM control chart, which combines the advantages of a Shewhart chart with the CUSUM chart. In this paper, we investigate 11 different standard deviation estimators with the structures of these 3 types of control charts for monitoring the process dispersion under normal and contaminated normal environments. By applying Monte Carlo simulations, we compare the performance of these memory charts depending on 4 factors: (1) standard deviation estimator, (2) parent environment, (3) chart type, and (4) change magnitude. Extensive simulations are used to compute and study the run length profiles of these memory charts, including the average, the standard deviation, the several percentiles, and the cumulative distribution function curves of the run length distribution. It turns out that there is a significant difference between the run length distribution of the memory chart with estimated parameters and the analogous case with known parameters, even using the adjusted control limits under normal environment, and the difference is more severe when contaminations are present. This difference is gradually diminished when a large number of Phase I samples is used under normality, but it is not true in the contaminated cases.
Definitions for warning signs and signs of severe dengue according to the WHO 2009 classification: Systematic review of literature
Authors: Morra Mostafa Ebraheem , Altibi Ahmed M.A. , Iqtadar Somia , Minh Le Huu Nhat , Elawady Sameh Samir , Hallab Asma , Elshafay Abdelrahman , Omer Omer Abedlbagi , Iraqi Ahmed , Adhikari Purushottam , Labib Jonair Hussein , Elhusseiny Khaled Mosaad , Elgebaly Ahmed , Yacoub Sophie , Huong Le Thi Minh , Hirayama Kenji , Huy Nguyen Tien
Published: April 2018

Since warning signs and signs of severe dengue are defined differently between studies, we conducted a systematic review on how researchers defined these signs. We conducted an electronic search in Scopus to identify relevant articles, using key words including dengue, “warning signs,” “severe dengue,” and “classification.” A total of 491 articles were identified through this search strategy and were subsequently screened by 2 independent reviewers for definitions of any of the warning or severe signs in the 2009 WHO dengue classification. We included all original articles published in English after 2009, classifying dengue by the 2009 WHO classification or providing the additional definition or criterion of warning signs and severity (besides the information of 2009 WHO). Analysis of the extracted data from 44 articles showed wide variations among definitions and cutoff values used by physicians to classify patients diagnosed with dengue infection. The establishment of clear definitions for warning signs and severity is essential to prevent unnecessary hospitalization and harmonizing the interpretation and comparability of epidemiological studies dedicated to dengue infection.
River connectivity reestablished:Effects and implications of six weir removals on brown trout smolt migration
Authors: Birnie‐Gauvin K. , Candee M.M. , Baktoft H. , Larsen M.H. , Koed A. , Aarestrup K.
Published: April 2018

Today's river systems have been extensively modified, requiring us to rethink how we approach the management of these important ecosystems. We evaluated the effects of removing 6 weirs in River Villestrup (Jutland, Denmark) on the smolt run of brown trout (Salmo trutta) over the course of 12 years. During 5 of these years, we evaluated the number, size, and timing of smolts during their downstream migration. We found an increase in smolt output following the weir removals, along with a decrease in average length and indications of an earlier peak migration. Our results suggest that barrier removal has led to an increase in spawning success by adults, fry survival, recruitment, and smolt migration success. Weir removal is therefore a viable management approach to restore connectivity in freshwater streams and rivers, which promotes the passage of smolts as they migrate to marine environments.
Fingerprinting Chamaesiphon populations as an approach to assess the quality of running waters
Authors: Loza V. , Morales A. , Perona E. , Muñoz‐Martín M. A. , Mateo P.
Published: April 2018

Cyanobacterial communities are highly diverse in freshwaters and respond rapidly to changing environments. Previous studies have highlighted variations in the structure and composition of epilithic cyanobacterial communities in response to eutrophication in watercourses. In the present study, changes in benthic cyanobacterial communities from Guadalix River (Spain) biofilms were examined using temperature‐gradient gel electrophoresis (TGGE) in conjunction with microscopic examination of field‐fixed samples, focusing on populations of one of the dominant cyanobacteria: Chamaesiphon. Environmental characteristics were determined in order to characterize the trophic status of the sampling sites. The presence of cyanobacteria in the river was determined from complex TGGE patterns, band extraction, and subsequent sequencing of 16S rDNA gene fragments. The microscopic observations revealed that the unicellular genus Chamaesiphon and the filamentous genus Phormidium were dominant in the studied locations. Within the 2 genera, 4 Chamaesiphon populations were identified (Chamaesiphon fuscus, Chamaesiphon starmachii, Chamaesiphon subglobosus, and Chamaesiphon polymorphus) and Phormidium was represented at the sampling sites by the Phormidium autumnale morphotype. TGGE banding patterns differed among samplings sites as a function of water quality. The genetic analysis revealed 4 phylotypes within the genus Chamaesiphon and 1 phylotype within the classic P. autumnale clade. Chamaesiphon phylotypes were not equally distributed in all the sampling locations. Some phylotypes were related to low nutrient concentrations, while others were associated with eutrophic conditions. Our results support the use of fingerprints of Chamaesiphon populations obtained by TGGE to examine changes in water quality.
How big is big enough? Toward a sustainable future by examining alternatives to the conventional economic growth paradigm
Authors: Harangozo Gabor , Csutora Maria , Kocsis Tamas
Published: April 2018

This study addresses how the sustainability crisis may be overcome by using alternatives to the conventional economic growth paradigm. Based on a literature review, the paper identifies and discusses three alternatives, namely negative, zero and positive economic growth. These alternatives are compared from a feasibility and policy perspective in relation to the transition toward sustainable development. The three alternatives are associated with very far‐reaching sets of policies that have different focal points with regard to how the paradigm shift from the conventional growth paradigm can be realized. All these alternatives, however, challenge the effectiveness of market forces. The shortcomings of the alternatives (resistance to voluntary transition with negative or zero growth, no proper consideration of the rebound effect for positive growth) hinder the transition and must be further addressed by policy‐makers in public and private sectors, as well as by civil society.
CMC/BiOCl 3D Hierarchical Nanostructures with Exposed {001} Facets and Its Enhanced Photocatalytic Activity
Authors: Sun Jingyu , Li Dongya , Li Yirui , Cai Yujie , Sun Lei , Yuan Xiangjuan , Cao Gang , Xu Haiming , Xia Dongsheng
Published: April 2018

CMC/BiOCl 3D hierarchical nanostructures with exposed {001} facets were successfully synthesized under the control of carboxymethyl cellulose (CMC). The physicochemical properties of as‐synthesized samples were characterized by X‐ray powder diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), UV–vis diffused reflectance spectra (DRS), Fourier transformed infrared (FT‐IR), Brunauer‐Emmett‐Teller (BET) measurements, and electron spin resonance (ESR). The results demonstrate that CMC makes great effects upon the morphology, structure and properties. BOC‐1 synthesized with CMC amount of 0.1 g exhibits highest visible photocatalytic activity on the degradation of Rhodamine B (RhB) for its 3D hierarchical nanostructures, thinnest nanosheets about 8.6 nm, appropriate band gap about 2.82 eV. The reaction rate of BOC‐1 is 4.5 times higher than that of pure BiOCl synthesized without CMC. Furthermore, the radicals and holes trapping experiments and electron spin resonance spectroscopy confirm ⋅O2− is the main active species, and a possible mechanism of CMC/BiOCl enhanced the photocatalytic activity was proposed.