bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting the noise in hybrid (phase and attenuation) x‐ray images acquired with the edge illumination technique
Authors: Hagen Charlotte Klara , Roche i Morgó Oriol , Olivo Alessandro 
Published: June 2020

PurposeTo analyze the noise performance of the edge illumination phase‐based x‐ray imaging technique when applying “single‐shot” phase retrieval. The latter consists in applying a sample‐specific low‐pass filter to the raw data, leading to “hybrid” images in which phase and attenuation contrast are merged with each other. The second objective is to compare the hybrid images with attenuation‐only images based on their respective signal‐to‐noise ratio (SNR).MethodsNoise is propagated from the raw images into the retrieved hybrid images, yielding analytic expressions for the variances and noise power spectra of the latter. An expression for the relative SNR between hybrid and attenuation images is derived. A comparison with simulated data is performed. Experimental data are also shown and discussed in the context of the theory.ResultsThe noise transfer into the retrieved hybrid images is strongly related to the setup and acquisition parameters, as well as the imaged sample itself. Consequently, the relative merit between hybrid and attenuation images also depends on these criteria. Generally, the hybrid approach tends to perform worse for highly attenuating samples, as the availability of phase contrast is outweighed by the loss of photons that is necessarily encountered in hybrid acquisitions. On the contrary, the hybrid approach can lead to a much better SNR for weakly attenuating samples, as here phase effects lead to much stronger contrast, outweighing the reduction in photon numbers.ConclusionsThe analytic expressions inform the design of edge illumination setups that lead to minimum noise transfer into the retrieved hybrid images. We also anticipate our theory to guide the decision as to which imaging mode (hybrid or attenuation) to use in order to maximize SNR for a specific sample.
Non‐water‐excitation MR spectroscopy techniques to explore exchanging protons in human brain at 3 T
Authors: Dziadosz Martyna , Bogner Wolfgang , Kreis Roland 
Published: June 2020

PurposeTo develop localization sequences for in vivo MR spectroscopy (MRS) on clinical scanners of 3 T to record spectra that are not influenced by magnetization transfer from water.MethodsImage‐selected in vivo spectroscopy (ISIS) localization and chemical‐shift‐selective excitation (termed I‐CSE) was combined in two ways: first, full ISIS localization plus a frequency‐selective spin‐echo and second, two‐dimensional (2D) ISIS plus a frequency‐selective excitation and slice‐selective refocusing. The techniques were evaluated at 3 T in phantoms and human subjects in comparison to standard techniques with water presaturation or metabolite‐cycling. ISIS included gradient‐modulated offset‐independent adiabatic (GOIA)‐type adiabatic inversion pulses; echo times were 8‐10 ms.ResultsThe novel 2D and 3D I‐CSE methods yield upfield spectra that are comparable to those from standard MRS, except for shorter echo times and a limited frequency range. On the downfield/high‐frequency side, they yield much more signal for exchangeable protons when compared to MRS with water presaturation or metabolite‐cycling and longer echo times.ConclusionNovel non‐water‐excitation MRS sequences offer substantial benefits for the detection of metabolite signals that are otherwise suppressed by saturation transfer from water. Avoiding water saturation and using very short echo times allows direct observation of faster exchanging moieties than was previously possible at 3 T and additionally makes the methods less susceptible to fast T2 relaxation.
Fast chemical exchange saturation transfer imaging based on PROPELLER acquisition and deep neural network reconstruction
Authors: Guo Chenlu , Wu Jian , Rosenberg Jens T. , Roussel Tangi , Cai Shuhui , Cai Congbo 
Published: June 2020

PurposeTo develop a method for fast chemical exchange saturation transfer (CEST) imaging.MethodsThe periodically rotated overlapping parallel lines enhanced reconstruction (PROPELLER) sampling scheme was introduced to shorten the acquisition time. Deep neural network was employed to reconstruct CEST contrast images. Numerical simulation and experiments on a creatine phantom, hen egg, and in vivo tumor rat brain were performed to test the feasibility of this method.ResultsThe results from numerical simulation and experiments show that there is no significant difference between reference images and CEST‐PROPELLER reconstructed images under an acceleration factor of 8.ConclusionAlthough the deep neural network is trained entirely on synthesized data, it works well on reconstructing experimental data. The proof of concept study demonstrates that the combination of the PROPELLER sampling scheme and the deep neural network enables considerable acceleration of saturated image acquisition and may find applications in CEST MRI.
A hybrid stochastic river environmental restoration modeling with discrete and costly observations
Authors: Yoshioka Hidekazu , Tsujimura Motoh , Hamagami Kunihiko , Yoshioka Yumi 
Published: June 2020

SummaryA recent river environmental restoration problem is approached from a standpoint of stochastic control of hybrid regime‐switching diffusion processes with discrete and costly observations. This setting harmonizes with real problems because continuously obtaining environmental and ecological information is difficult, and is often costly. The main problem is to decide when and how much of the sediment should be supplied into a river environment to effectively suppress bloom of benthic algae. The interventions are allowed only at observation times. Finding the optimal river restoration policy ultimately reduces to solving an optimality equation in an unconventional form due to the observation cost and discrete observations. We show its unique solvability and present a connection with degenerate parabolic partial differential equations, with which we can construct an effective algorithm for its approximation. An uncertainty‐averse optimization problem is also considered as an advanced problem. Coefficients and parameter values are identified from experimental and observation results to numerically compute the optimal restoration policy of an existing river environment with and without uncertainty.
Gifted underachievement within a self‐regulated learning framework: Proposing a task‐dependent model to guide early identification and intervention
Authors: Ridgley Lisa M. , DaVia Rubenstein Lisa , Callan Gregory L. 
Published: June 2020

AbstractCurrent theoretical and operational definitions of underachievement require that students show sustained suppressed academic achievement. Yet, early detection may allow for effective intervention before underachievement becomes a chronic issue. While existing identification procedures were not designed to detect underachievement before low academic performance occurs, the integration of self‐regulated learning (SRL) into these practices may promote earlier identification and intervention. This conceptual paper (a) anchors gifted underachievement within Zimmerman's SRL model, (b) examines existing gifted literature investigating SRL components to demonstrate the benefits of applying an SRL model, and (c) proposes a comprehensive measurement and intervention technique to capture important motivational variables at the task level. By measuring SRL processes and underachievement at a task‐specific level, we can target interventions to specific needs, address underachievement before it becomes a persistent problem, and help learners reach their academic potential.
Angiotensin‐converting enzyme 2: The old door for new severe acute respiratory syndrome coronavirus 2 infection
Authors: Tan Heng Wee , Xu Yan‐Ming , Lau Andy T. Y. 
Published: June 2020

SummaryCoronavirus (CoV) disease 2019 (COVID‐19) is an ongoing pandemic caused by severe acute respiratory syndrome CoV 2 (SARS‐CoV‐2). The highly contagious SARS‐CoV‐2 belongs to the genus Betacoronavirus, and it is phylogenetically closely related to SARS‐CoV, a human CoV that caused an outbreak back in 2002 to 2003. Both SARS‐CoV‐2 and SARS‐CoV enter human cells via the interactions between viral crown‐like spike protein and human angiotensin‐converting enzyme 2 (ACE2) receptor. Here, we aim to review the involvement of ACE2 in human CoV infections by discussing the roles of ACE2 in CoV evolution, cross‐species transmissibility, and COVID‐19 susceptibility. We also provide our perspectives on COVID‐19 treatment and prevention.
Conjunctival reconstruction via enrichment of human conjunctival epithelial stem cells by p75 through the NGF-p75-SALL2 signaling axis
Authors: Wu Nianxuan , Yan Chenxi , Chen Junzhao , Yao Qinke , Lu Yang , Yu Fei , Sun Hao , Fu Yao 
Published: June 2020

AbstractSevere conjunctival diseases can cause significant conjunctival scarring, which seriously limits eye movement and affects patients’ vision. Conjunctival reconstruction remains challenging due to the lack of efficient methods for stem cells enrichment. This study indicated that p75 positive conjunctival epithelial cells (CjECs) were mainly located in the basal layer of human conjunctival epithelium and showed an immature differentiation state in vivo. The p75 strongly positive (p75++) CjECs enriched by immuno-magnetic beads exhibited high expression of stem cell markers and low expression of differentiated keratins. During continuous cell passage cultivation, p75++ CjECs showed the strongest proliferation potential and were able to reconstruct the conjunctiva in vivo with the most complete structure and function. Exogenous addition of NGF promoted the differentiation of CjECs by increasing nuclear localization of SALL2 in p75++ CjECs while proNGF played an opposite role. Altogether, p75++ CjECs present stem cell characteristics and exhibit the strongest proliferation potential so can be used as seed cells for conjunctival reconstruction, and NGF-p75-SALL2 signaling pathway was involved in regulating the differentiation of CjECs.
Grafted human pluripotent stem cell-derived cortical neurons integrate into adult human cortical neural circuitry
Authors: Grønning Hansen Marita , Laterza Cecilia , Palma-Tortosa Sara , Kvist Giedre , Monni Emanuela , Tsupykov Oleg , Tornero Daniel , Uoshima Naomi , Soriano Jordi , Bengzon Johan , Martino Gianvito , Skibo Galyna , Lindvall Olle , Kokaia Zaal 
Published: June 2020

Abstract
Several neurodegenerative diseases cause loss of cortical neurons, leading to sensory, motor, and cognitive impairments. Studies in different animal models have raised the possibility that transplantation of human cortical neuronal progenitors, generated from pluripotent stem cells, might be developed into a novel therapeutic strategy for disorders affecting cerebral cortex. For example, we have shown that human long-term neuroepithelial-like stem (lt-NES) cell-derived cortical neurons, produced from induced pluripotent stem cells and transplanted into stroke-injured adult rat cortex, improve neurological deficits and establish both afferent and efferent morphological and functional connections with host cortical neurons. So far, all studies with human pluripotent stem cell-derived neurons have been carried out using xenotransplantation in animal models. Whether these neurons can integrate also into adult human brain circuitry is unknown. Here, we show that cortically fated lt-NES cells, which are able to form functional synaptic networks in cell culture, differentiate to mature, layer-specific cortical neurons when transplanted ex vivo onto organotypic cultures of adult human cortex. The grafted neurons are functional and establish both afferent and efferent synapses with adult human cortical neurons in the slices as evidenced by immuno-electron microscopy, rabies virus retrograde monosynaptic tracing, and whole-cell patch-clamp recordings. Our findings provide the first evidence that pluripotent stem cell-derived neurons can integrate into adult host neural networks also in a human-to-human grafting situation, thereby supporting their potential future clinical use to promote recovery by neuronal replacement in the patient’s diseased brain.
A microfoundational model of real options reasoning: The roles of individual search propensity and perceived uncertainty
Authors: Zhang Stephen X. , Gao Renfei , Odeh Nicolás , Leatherbee Michael 
Published: June 2020

AbstractResearch SummaryTo explain heterogeneity in real options reasoning (ROR) across entrepreneurial ventures, we propose a microfoundational model to explore the relationships between a firm leader's search propensity, perceived uncertainty and the firm‐level ROR‐based behaviors. Using a panel survey of 134 founder‐CEOs of new ventures, we find that founder‐CEOs' search propensity is positively related to ROR‐based behaviors in their ventures. Moreover, we find that founder‐CEOs' perceived effect uncertainty is positively related to the ROR‐based behaviors, but perceived response uncertainty is negatively related to the ROR‐based behaviors, revealing the importance of considering distinct types of uncertainty in entrepreneurs' ROR. Our microfoundational model advances the ROR literature by delineating how individual‐level factors may drive ROR in firms that face uncertainty.Managerial SummaryFlexibility is key to startup success. However, entrepreneurs craft and embed flexibility to different degrees and under different situations. In order to explain this heterogeneity, we study the roles of entrepreneurs' individual characteristics. Particularly, we study search propensity and perceived uncertainty (distinguishing among different types) in relation to flexibility, formally known as real options reasoning (ROR). Analysis of 134 founder‐CEOs of new ventures in Start‐Up Chile showed that founder‐CEOs' search propensity is positively related to ROR in their ventures. Moreover, founder‐CEOs' perceived uncertainty is related to ROR in ways that depend on the type of uncertainty the entrepreneurs perceive; thus, not all types of uncertainties relate positively to ROR. Such findings carry managerial implications to those who want to understand why certain startups are more flexible.
Conformation‐Tuning Effect of Asymmetric Small Molecule Acceptors on Molecular Packing, Interaction, and Photovoltaic Performance
Authors: Luo Zhenghui , Ma Ruijie , Xiao Yiqun , Liu Tao , Sun Huiliang , Su Mengyao , Guo Qing , Li Guanghao , Gao Wei , Chen Yuzhong , Zou Yang , Guo Xugang , Zhang Maojie , Lu Xinhui , Yan He , Yang Chuluo 
Published: June 2020

AbstractUnderstanding the conformation effect on molecular packing, miscibility, and photovoltaic performance is important to open a new avenue for small‐molecule acceptor (SMA) design. Herein, two novel acceptor–(donor‐acceptor1‐donor)–acceptor (A‐DA1D‐A)‐type asymmetric SMAs are developed, namely C‐shaped BDTP‐4F and S‐shaped BTDTP‐4F. The BDTP‐4F‐based polymer solar cells (PSCs) with PM6 as donor, yields a power conversion efficiency (PCE) of 15.24%, significantly higher than that of the BTDTP‐4F‐based device (13.12%). The better PCE for BDTP‐4F‐based device is mainly attributed to more balanced charge transport, weaker bimolecular recombination, and more favorable morphology. Additionally, two traditional A‐D‐A‐type SMAs (IDTP‐4F and IDTTP‐4F) are also synthesized to investigate the conformation effect on morphology and device performance. Different from the device result above, here, IDTP‐4F with S‐shape conformation outperforms than IDTTP‐4F with C‐shape conformation. Importantly, it is found that for these two different types of SMA, the better performing binary blend has similar morphological characteristics. Specifically, both PM6:BDTP‐4F and PM6:IDTP‐4F blend exhibit perfect nanofibril network structure with proper domain size, obvious face‐on orientation and enhance donor‐acceptor interactions, thereby better device performance. This work indicates tuning molecular conformation plays pivotal role in morphology and device effciciency, shining a light on the molecular design of the SMAs.
Cell Behavior within Nanogrooved Sandwich Culture Systems
Authors: Bjørge Isabel M. , Salmeron‐Sanchez Manuel , Correia Clara R. , Mano João F. 
Published: June 2020

AbstractGrooved topography and inherent cell contact guidance has shown promising results regarding cell proliferation, morphology, and lineage‐specific differentiation. Yet these approaches are limited to 2D applications. Sandwich‐culture conditions are developed to bridge the gap between 2D and 3D culture, enabling both ventral and dorsal cell surface stimulation. The effect of grooved surface topography is accessed on cell orientation and elongation in a highly controlled manner, with simultaneous and independent stimuli on two cell sides. Nanogrooved and non‐nanogrooved substrates are assembled into quasi‐3D systems with variable relative orientations. A plethora of sandwich‐culture conditions are created by seeding cells on lower, upper, or both substrates. Software image analysis demonstrates that F‐actin of cells acquires the orientation of the substrate on which cells are initially seeded, independently from the orientation of the second top substrate. Contrasting cell morphologies are observed, with a higher elongation for nanogrooved 2D substrates than nanogrooved sandwich‐culture conditions. Correlated with an increased pFAK activity and vinculin staining for sandwich‐culture conditions, these results point to an enhanced cell surface stimulation versus control conditions. The pivotal role of initial cell‐biomaterial contact on cellular alignment is highlighted, providing important insights for tissue engineering strategies aiming to guide cellular response through mechanotransduction approaches.
Burrows‐Wheeler post‐transformation with effective clustering and interpolative coding
Authors: Niemi Arto , Teuhola Jukka 
Published: June 2020

SummaryLossless compression methods based on the Burrows‐Wheeler transform (BWT) are regarded as an excellent compromise between speed and compression efficiency: they provide compression rates close to the PPM algorithms, with the speed of dictionary‐based methods. Instead of the laborious statistics‐gathering process used in PPM, the BWT reversibly sorts the input symbols, using as the sort key as many following characters as necessary to make the sort unique. Characters occurring in similar contexts are sorted close together, resulting in a clustered symbol sequence. Run‐length encoding and Move‐to‐Front (MTF) recoding, combined with a statistical Huffman or arithmetic coder, is then typically used to exploit the clustering. A drawback of the MTF recoding is that knowledge of the character that produced the MTF number is lost. In this paper, we present a new, competitive Burrows‐Wheeler posttransform stage that takes advantage of interpolative coding—a fast binary encoding method for integer sequences, being able to exploit clusters without requiring explicit statistics. We introduce a fast and simple way to retain knowledge of the run characters during the MTF recoding and use this to improve the clustering of MTF numbers and run‐lengths by applying reversible, stable sorting, with the run characters as sort keys, achieving significant improvement in the compression rate, as shown here by experiments on common text corpora.
Steel box‐girder bridge decks with curved bottom flange
Authors: Ljubinković Filip , Martins João Pedro Simões Cândido , dos Santos Gervásio Helena Maria , da Silva Luís Alberto Proença Simões 
Published: June 2020

AbstractNominated for the Professor Eduardo de Arantes e Oliveira Award at XII Conference on Steel and Composite Construction in Coimbra 2019This paper presents the results of a numerical parametric study that investigated the M‐V interaction behaviour of box‐girder bridge deck specimens. The study made use of an advanced numerical model that was previously verified against the experimental results. Based on the numerical results and the current rules for trapezoidal box girders, new design models are proposed for predicting the bending and shear resistance of cross‐sections with a curved bottom flange. Additionally, the force‐based M‐V interaction equation proposed by Jáger et al. [1], adopted in the new version of EN 1993‐1‐5 [2], was verified and slightly modified to fit this type of cross‐section.
Production of high‐purity galacto‐oligosaccharides by depleting glucose and lactose from galacto‐oligosaccharide syrup with yeasts
Authors: Pázmándi Melinda , Kovács Zoltán , Balga Edina , Kovács Mónika , Maráz Anna 
Published: June 2020

AbstractGalacto‐oligosaccharides (GOS) are prebiotic compounds, widely used as ingredients in various food, nutraceutical and pharmaceutical products. Enzymatic synthesis of GOS results in low‐purity products that contain high amounts of glucose and lactose beside the valuable GOS. In this study, a systematic approach was used to develop yeast‐based fermentation strategies to purify crude GOS. Potentially applicable yeast strains were identified based on an extensive search in literature databases followed by a series of laboratory‐scale fermentation tests. Single‐ and two‐step fermentation processes were designed for the removal of glucose alone or together with lactose from crude GOS syrup. Single‐step fermentation trials with two strains of previously unreported species, Cyberlindnera jadinii NCAIM Y.00499 and Kluyveromyces nonfermentans NCAIM Y.01443, resulted in purified products free of both glucose and ethanol from a crude GOS syrup diluted to 15 and 10 w/v%, respectively. Simultaneous removal of glucose and lactose was achieved by Kluyveromyces marxianus DMB Km‐RK in a single‐step fermentation process with a yield of 97.5% and final purity of 100%. A two‐step fermentation approach was designed to allow conversion of a glucose‐free product into a high‐purity GOS by removing glucose with C. jadinii Y.00499 in the first step, and lactose by Kluyveromyces lactis DMB Kl‐RK in the second step, resulting in a final product with a yield of 100% and a final purity of 92.1%. These results indicate that the selected nonconventional yeasts are promising candidates for the removal of non‐GOS components from commercial crude GOS products by selective fermentation.
The Kinematic Alignment Technique for Total Knee Arthroplasty
Authors: Rivière Charles , Harman Ciara , Boughton Oliver , Cobb Justin 
Published: June 2020

AbstractThe kinematic alignment technique (KA) for total knee arthroplasty (TKA) is a surgical technique recently developed that aims to anatomically position and kinematically align total knee components [1]. The kinematic implantation aims to resurface the knee joint by removing a cartilage and bone thickness equivalent to the implant thickness and where the knee implants are aligned on the knee kinematic axes that dictate motion of the patella and tibia around the distal femoral epiphysis [2–4]. Similar to unicompartmental knee replacement, kinematically aligning total knee components restores the constitutional knee joint line orientation and the physiological knee laxity without the need for soft-tissue release [5] (Fig. 16.1).
Joint Functional Calculus for Definitizable Self-adjoint Operators on Krein Spaces
Authors: Kaltenbäck Michael , Skrepek Nathanael 
Published: June 2020

AbstractIn the present note a spectral theorem for a finite tuple of pairwise commuting, self-adjoint and definitizable bounded linear operators $$A_1,\ldots ,A_n$$

A
1

,
…
,

A
n

on a Krein space is derived by developing a functional calculus $$\phi \mapsto \phi (A_1,\ldots ,A_n)$$

ϕ
↦
ϕ
(

A
1

,
…
,

A
n

)

which is the proper analogue of $$\phi \mapsto \int \phi \, dE$$

ϕ
↦
∫
ϕ

d
E

in the Hilbert space situation with the common spectral measure E for a finite tuple of pairwise commuting, self-adjoint bounded linear operators.