bluuebunny/crossref_metadata_2025 huggingface dataset:
Patient‐reported reasons for declining same‐day antiretroviral therapy initiation in routine HIV care settings in Lusaka, Zambia: results from a mixed‐effects regression analysis
Authors: Pry Jake , Chipungu Jenala , Smith Helene J , Bolton Moore Carolyn , Mutale Jacob , Duran‐Frigola Miquel , Savory Theodora , Herce Michael E
Published: July 2020

Introduction

In the current “test and treat” era, HIV programmes are increasingly focusing resources on linkage to care and same‐day antiretroviral therapy (ART) initiation to meet UNAIDS 95‐95‐95 targets. After observing sub‐optimal treatment indicators in health facilities supported by the Centre for Infectious Disease Research in Zambia (CIDRZ), we piloted a “linkage assessment” tool in facility‐based HIV testing settings to uncover barriers to same‐day linkage to care and ART initiation among newly identified people living with HIV (PLHIV) and to guide HIV programme quality improvement efforts.

Methods

The one‐page, structured linkage assessment tool was developed to capture patient‐reported barriers to same‐day linkage and ART initiation using three empirically supported categories of barriers: social, personal and structural. The tool was implemented in three health facilities, two urban and one rural, in Lusaka, Zambia from 1 November 2017 to 31 January 2018, and administered to all newly identified PLHIV declining same‐day linkage and ART. Individuals selected as many reasons as relevant. We used mixed‐effects logistic regression modelling to evaluate predictors of citing specific barriers to same‐day linkage and ART, and Fisher’s Exact tests to assess differences in barrier citation by socio‐demographics and HIV testing entry point.

Results

A total of 1278 people tested HIV positive, of whom 126 (9.9%) declined same‐day linkage and ART, reporting a median of three barriers per respondent. Of these 126, 71.4% were female. Females declining same‐day ART were younger, on average, (median 28.5 years, interquartile range (IQR): 21 to 37 years) than males (median 34.5 years, IQR: 26 to 44 years). The most commonly reported barrier category was structural, “clinics were too crowded” (n = 33), followed by a social reason, “friends and family will condemn me” (n = 30). The frequency of citing personal barriers differed significantly across HIV testing point (χ2 p = 0.03). Significant predictors for citing ≥1 barrier to same‐day ART were >50 years of age (OR: 12.59, 95% CI: 6.00 to 26.41) and testing at a rural facility (OR: 9.92, 95% CI: 4.98 to 19.79).

Conclusions

Given differences observed in barriers to same‐day ART initiation reported across sex, age, testing point, and facility type, new, tailored counselling and linkage to care approaches are needed, which should be rigorously evaluated in routine programme settings.
Surmounting the obstacles that impede effective CAR T cell trafficking to solid tumors
Authors: Donnadieu Emmanuel , Dupré Loïc , Pinho Lia Gonçalves , Cotta-de-Almeida Vinicius
Published: July 2020

Innovative immunotherapies based on immune checkpoint targeting antibodies and engineered T cells are transforming the way we approach cancer treatment. However, although these T cell centered strategies result in marked and durable responses in patients across many different tumor types, they provide therapeutic efficacy only in a proportion of patients. A major challenge of immuno-oncology is thereby to identify mechanisms responsible for resistance to cancer immunotherapy in order to overcome them via adapted strategies that will ultimately improve intrinsic efficacy and response rates. Here, we focus on the barriers that restrain the trafficking of chimeric antigen receptor (CAR)-expressing T cells to solid tumors. Upon infusion, CAR T cells need to home into malignant sites, navigate within complex tumor environments, form productive interactions with cancer cells, deliver their cytotoxic activities, and finally persist. We review the accumulating evidence that the microenvironment of solid tumors contains multiple obstacles that hinder CAR T cells in the dynamic steps underlying their trafficking. We focus on how these hurdles may in part account for the failure of CAR T cell clinical trials in human carcinomas. Given the engineered nature of CAR T cells and possibilities to modify the tumor environment, there are ample opportunities to augment CAR T cell ability to efficiently find and combat tumors. We present some of these strategies, which represent a dynamic field of research with high potential for clinical applicability.
Interplay between alveolar epithelial and dendritic cells and Mycobacterium tuberculosis
Authors: Rodrigues Tamara Silva , Conti Bruno José , Fraga-Silva Thais Fernanda de Campos , Almeida Fausto , Bonato Vânia Luiza Deperon
Published: July 2020

The innate response plays a crucial role in the protection against tuberculosis development. Moreover, the initial steps that drive the host-pathogen interaction following Mycobacterium tuberculosis infection are critical for the development of adaptive immune response. As alveolar Mϕs, airway epithelial cells, and dendritic cells can sense the presence of M. tuberculosis and are the first infected cells. These cells secrete mediators, which generate inflammatory signals that drive the differentiation and activation of the T lymphocytes necessary to clear the infection. Throughout this review article, we addressed the interaction between epithelial cells and M. tuberculosis, as well as the interaction between dendritic cells and M. tuberculosis. The understanding of the mechanisms that modulate those interactions is critical to have a complete view of the onset of an infection and may be useful for the development of dendritic cell-based vaccine or immunotherapies.
Anti-CD20 rituximab IgG1, IgG3, and IgG4 but not IgG2 subclass trigger Ca2+ mobilization and cytotoxicity in human NK cells
Authors: Freitas Monteiro Marta , Papaserafeim Maria , Réal Aline , Puga Yung Gisella L , Seebach Jörg D
Published: July 2020

NK cell-mediated Ab-dependent cellular cytotoxicity (ADCC) is increasingly recognized to play an important role in cancer immunotherapy, transplant rejection, and autoimmunity. However, several aspects of the molecular interactions of IgG subclasses with the Fc-gamma receptor IIIA (FcγRIIIA)/CD16a expressed on NK cells remain unknown. The aim of the current study was to further analyze the role of IgG subclasses and FCGR3A V158F single nucleotide polymorphism (SNP) on Ca2+ signaling and NK cell-mediated ADCC against Daudi target cells in vitro. NK cells were isolated from donors with different FCGR3A SNP. The affinity of rituximab IgG subclasses to CD20 expressed on Daudi cells showed similar dissociation constant as tested by flow cytometry. Induction of Ca2+ signaling, degranulation, intracellular cytokine production, and ADCC was demonstrated for IgG1 and IgG3, to a lesser degree also for IgG4, but not for IgG2. Compared to NK cells carrying the low-affinity (FF) variant for the FCGR3A V158F SNP, binding of IgG1 and IgG3 to NK cells carrying the high-affinity (VV) and VF SNP variants was two- to threefold higher. Variations of FCGR3A SNP among the eight tested donors (1 VV, 3FF, and 4VF) revealed no significant differences of Ca2+ signaling and degranulation; however, ADCC was somewhat weaker in donors with the low-affinity FF variation. In conclusion, this is the first study correlating Ca2+ signaling and NK cell-mediated ADCC triggered by the four IgG subclasses with the FCGR3A V158F SNP. Our findings indicate important differences in the interactions of IgG subclasses with FcγRIIIA/CD16a but no major impact of FCGR3A SNP and may therefore help to better correlate the functional properties of particular engineered therapeutic antibodies in vitro with individual differences of their clinical efficacy.
Cost‐efficient performance‐driven modelling of multi‐band antennas by variable‐fidelity electromagnetic simulations and customized space mapping
Authors: Koziel Slawomir , Pietrenko‐Dabrowska Anna
Published: July 2020

Electromagnetic (EM) simulations have become an indispensable tool in the design of contemporary antennas. EM‐driven tasks, for example, parametric optimization, entail considerable computational efforts, which may be reduced by employing surrogate models. Yet, data‐driven modelling of antenna characteristics is largely hindered by the curse of dimensionality. This may be addressed using the recently reported domain‐confinement techniques, especially the nested‐kriging framework, which permits rendering of reliable surrogates over wide ranges of antenna parameters while greatly reducing the computational overhead of training data acquisition. Focused on modelling of multi‐band antennas, this paper attempts to reduce the cost of surrogate construction even further by incorporating variable‐fidelity simulations into the nested kriging. The principal challenge being design‐dependent frequency shifts between the models of various fidelities is handled through the development of a customized frequency scaling and output space mapping. Validation is carried out using a dual‐band dipole antenna modeled over broad ranges of operating conditions. A small training data set is sufficient to secure the predictive power comparable to that of the nested kriging model set up using solely high‐fidelity data, and by far exceeding the accuracy of conventional surrogates. Application examples for antenna optimization and experimental verification of the selected designs are also provided.
Dominant factor of dry‐wet change in China since 1960s
Authors: Xu Jinqin , Wang Dandan , Qiu Xinfa , Zeng Yan , Zhu Xiaochen , Li Mengxi , He Yongjian , Shi Guoping
Published: July 2020

The dry‐wet climate conditions of an area are mainly determined by the water input (e.g., precipitation, P) and output (e.g., potential evapotranspiration, PET). Based on three dry‐wet indices and the differential equation, this study designed a new attribution method to quantify the contributions of P and PET to the dry‐wet change, so as to determine the dominant factors of the dry‐wet change over whole China (CHINA) and various hydroclimate regions (i.e., arid region, AR; semi‐arid region, SAR; semi‐humid region, SHR; and humid region, HR) during 1960–2018 and six interdecadal periods. Results showed that the overall weak drying in CHINA was dominated by an increase in PET, while climate humidification in AR and HR was dominated by an increase in P, climate drying in SHR was dominated by the reduced P, and the weak drying in SAR was co‐dominated by P and PET during 1960–2018. The dominant factors of dry‐wet change over CHINA and each hydroclimate region varied in different decades. Briefly, climate humidification in CHINA and various hydroclimate regions was basically dominated by P in different decades, and the drying was mainly dominated by P in the 1960s–1980s, but the contribution of PET to climate drying began to become prominent after the 1980s. Besides, we found that P contributed more to dry‐wet change than PET on the station and regional scales, but the contribution of P to climate drying on a national scale was underestimated to some extent due to the regional offset effect of the increase/decrease in P during 1960–2018, as well as in the 1990s. These findings implied that the importance of research on the regional or local scale, and equal attention should be paid to the effects of P and PET changes in the future drought or dry‐wet change research.
The effect of age and sex on pelvic bone density measured opportunistically in clinical CT scans
Authors: Telfer Scott , Brunnquell Christina L. , Allen Jerad D. , Linnau Ken F. , Zamora David , Kleweno Conor P.
Published: July 2020

Unstable pelvic ring fractures are severe and complex injuries, and surgical fixation is challenging and can be complicated by early failure due in part to difficulties with securely fixing screws in low‐density bone. There is limited information in the literature about how the density distribution across the pelvic bones changes with age and sex. In this study, we used 60 sets of calibrated bone density measurements obtained opportunistically from clinical computed tomography scans of the pelvis. Three‐dimensional models of the innominate bone were produced and the effects of age and sex on cortical bone density modeled. Overall trends and regions where these factors had a significant effect were identified, and the results visualized. Across the entire innominate bone, the mean loss of density was found to be 1.6 mg/cc per year, with several specific areas (pubic body, iliac fossa, posterior ilium, and anterior inferior iliac spine for example) showing significant rates of loss up to three times greater than the rest of the bone. Areas significantly affected by sex included the posterior pubic root, anterior aspect of the pubic body, and iliac crest. Despite overall trends of attenuation, there remains significant variability between individuals. This supports the need to further explore subject‐specific planning tools for pelvic fracture repair.

Statement of clinical significance: Bone density changes across the innominate bone due to age and sex tend to vary between individuals, although consistent effects were seen at specific regions. This information may help in surgical planning of unstable fracture repairs.
Evolution of Olfactory Disorders in COVID‐19 Patients
Authors: Gorzkowski Victor , Bevilacqua Sibylle , Charmillon Alexandre , Jankowski Roger , Gallet Patrice , Rumeau Cécile , Nguyen Duc Trung
Published: July 2020

Objectives

A high frequency and a strong association of olfactory/gustatory impairment with COVID‐19 were reported. Its spontaneous evolution remains unknown. The aim of this study was to investigate the spontaneous evolution of olfactory disorders in COVID‐19 patients.

Study Design

Cross‐sectional study.

Methods

A total of 229 patients with laboratory‐confirmed COVID‐19 from March 1 through 31, 2020 in our institution were included. Among them, 140 patients (mean age, 38.5 years, 89 women) reported sudden olfactory/gustatory disorders during COVID‐19. All patients were interviewed by phone based on a questionnaire with 16 questions at time of survey. The primary end point was olfactory recovery rate at time of survey.

Results

The frequency of patients with olfactory disorders was higher before March 20, 2020 than since (70.3% vs. 53.9%, respectively) (P = .016). At time of survey (26 days of the mean time from anosmia onset), 95.71% reported to start an olfactory recovery. The mean time from olfactory loss onset to recovery onset was 11.6 days. Recovery started between the fourth and the fifteenth day after olfactory loss onset in 78.4% of patients. Complete olfactory recovery happened for 51.43% of patients. There was a significant relationship between the complete olfactory recovery and a short time from olfactory loss onset to recovery onset (P = .0004), absence of nasal obstruction (P = .023) and absence of sore/dry/tingling feeling in the nose (P = .007) in COVID‐19 patients.

Conclusion

Knowledge of spontaneous evolution of olfactory disorders allows reassuring patients and planning therapeutic strategies for persistent olfactory dysfunction after having definitely recovered from COVID‐19.

Level of Evidence

4 Laryngoscope, 130:2667–2673, 2020
More on trees and Cohen reals
Authors: Laguzzi Giorgio , Stuber‐Rousselle Brendan
Published: July 2020

In this paper we analyse some questions concerning trees on κ, both for the countable and the uncountable case, and the connections with Cohen reals. In particular, we provide a proof for one of the implications left open in [6, Question 5.2] about the diagram for regularity properties.
Hyponormality on an annulus with a weight
Authors: Sadraoui Houcine , Halouani Borhen
Published: July 2020

In this work, we consider the hyponormality of Toeplitz operators on the Bergman space of the annulus with a logarithmic weight. We give necessary conditions when the symbol is of the form
, where ψ and φ are analytic on the annulus
.
Some approximate relations in the photoelasticity of strongly anisotropic crystals
Authors: Daví Fabrizio
Published: July 2020

The knowledge of the principal refractive indices and their dependence on the applied stress is the starting point for any experimental analysis of transparent crystals. Because for strongly anisotropic crystals and a general state of stress an explicit analytical solution can be difficult to obtain, then we need some approximated solutions. Here, we propose a coherent approximation procedure that generalizes results already obtained and give a simple example of application.
Grape Powder Supplementation Attenuates Prostate Neoplasia Associated with Pten Haploinsufficiency in Mice Fed High‐Fat Diet
Authors: Joshi Tanvi , Patel Ishani , Kumar Avinash , Donovan Virginia , Levenson Anait S.
Published: July 2020

Scope

Previous studies have identified potent anticancer activities of polyphenols in preventing prostate cancer. The aim of the current study is to evaluate the chemopreventive potential of grape powder (GP) supplemented diets in genetically predisposed and obesity‐provoked prostate cancer.

Methods and results

Prostate‐specific Pten heterozygous (Pten+/f) transgenic mice are fed low‐ and high‐fat diet (LFD and HFD, respectively) supplemented with 10% GP for 33 weeks, ad libitum. Prostate tissues are characterized using immunohistochemistry and western blots, and sera are analyzed by ELISA and qRT‐PCR. Pten+/f mice fed LFD and HFD supplemented with 10% GP show favorable histopathology, significant reduction of the proliferative rate of prostate epithelial cells (Ki67), and rescue of PTEN expression. The most potent protective effect of GP supplementation is detected against HFD‐induced increase in inflammation (IL‐1β; TGF‐β1), activation of cell survival pathways (Akt, AR), and angiogenesis (CD31) in Pten+/f mice. Moreover, GP supplementation reduces circulating levels of oncogenic microRNAs (miR‐34a; miR‐22) in Pten+/f mice. There are no significant changes in body weight and food intake in GP supplemented diet groups.

Conclusions

GP diet supplementation can be a beneficial chemopreventive strategy for obesity‐related inflammation and prostate cancer progression. Monitoring serum miRNAs can facilitate the non‐invasive evaluation of chemoprevention efficacy.
Printed compact asymmetric dual L‐strip fed split‐ring shaped EBG‐based textile antenna for WBAN applications
Authors: Singh Saurabh , Verma Sudhanshu
Published: July 2020

This letter presents a design of very compact asymmetric dual L‐strip fed split‐ring shaped electromagnetic bandgap (EBG)‐based textile antenna for wireless body area networks (WBAN) applications, operating at frequency 2.45 GHz. The antenna radiator is composed of 2 × 1 array of EBG cells printed on same side of the substrate with partial ground plane to form a compact EBG surface, excited with a 50 Ω inverted L‐strip feed line. The partial ground plane with EBG cells is used to miniaturize the proposed antenna of size 40 × 20 × 0.3 mm3. The proposed compact asymmetric dual L‐strip fed wearable antenna (DLSWA) with EBG structure is fabricated on denim (jeans) substrate having dielectric constant (ɛr) 1.7 and thickness of 0.3 mm. The design of proposed antenna is optimized for Industrial, Scientific, and Medical (ISM) band (2.4‐2.48 GHz)through various parametric variations with simulated impedance bandwidth (BW) of 12.2% (2.3‐2.6 GHz) for reflection coefficient |S11| ≤ −10 dB and also exhibits stable radiation patterns with simulated peak realized gain of almost 3.5 dBi in the entire operational frequency band. The performance of proposed wearable antenna on human body is also studied and observed low specific absorption rate (SAR) value of 0.6 W/kg over 10 g of human tissues. The proposed compact asymmetric DLSWA is designed, fabricated, and tested. The simulated results of designed antenna are verified and validated with measured results which show good agreement for all radiation characteristics of proposed antenna for WBAN applications.
On competitive analysis for polling systems
Authors: Xu Jin , Gautam Natarajan
Published: July 2020

Polling systems have been widely studied, however most of these studies focus on polling systems with renewal processes for arrivals and random variables for service times. There is a need driven by practical applications to study polling systems with arbitrary arrivals (not restricted to time‐varying or in batches) and revealed service time upon a job's arrival. To address that need, our work considers a polling system with generic setting and for the first time provides the worst‐case analysis for online scheduling policies in this system. We provide conditions for the existence of constant competitive ratios, and competitive lower bounds for general scheduling policies in polling systems. Our work also bridges the queueing and scheduling communities by proving the competitive ratios for several well‐studied policies in the queueing literature, such as cyclic policies with exhaustive, gated or l‐limited service disciplines for polling systems.
Feasibility of precise and reliable glucose quantification in human whole blood samples by 1 tesla benchtop NMR
Authors: Stolz Michael , Schlawne Carolin , Hoffmann Jens , Hartmann Vanessa , Marini Irene , Fritsche Andreas , Peter Andreas , Bakchoul Tamam , Schick Fritz
Published: July 2020

The standard procedure for blood glucose measurements is enzymatic testing. This method is cheap, but requires small samples of open blood with direct contact to the test medium. In principle, NMR provides non‐contact analysis of body fluids, but high‐field spectrometers are expensive and cannot be easily utilized under clinical conditions. Low‐field NMR systems with permanent magnets are becoming increasingly smaller and more affordable. The studies presented here aim at exploring the capabilities of low‐field NMR for measuring glucose concentrations in whole blood. For this purpose, a modern 1 T benchtop NMR spectrometer was used. Challenges arise from broad spectral lines, the glucose peak locations close to the water signal, low SNR and the interference with signals from other blood components. Whole blood as a sample comprises even more boundary conditions: crucial for reliable results are avoiding the separation of plasma and cells by gravitation and reliable reference values. First, the accuracy of glucose levels measured by NMR was tested using aqueous glucose solutions and commercially available bovine plasma. Then, 117 blood samples from oral glucose tolerance testing were measured with minimal preparation by simple pulse‐acquire NMR experiments. The analysis itself is the key to achieve high precision, so several approaches were investigated: peak integration, orthogonal projection to latent structure analysis and support vector machine regression. Correlations between results from the NMR spectra and the routine laboratory automated analyzer revealed an RMSE of 7.90 mg/dL for the best model. 91.5% of the model output lies within the limits of the German Medical Association guidelines, which require the glucose measurement to be within 11% of the reference method. It is concluded that spectral quantification of glucose in whole blood samples by high‐quality NMR spectrometers operating at 1 T is feasible with sufficient accuracy.
Overcoming the cohesive zone limit in composites delamination: modeling with slender structural elements and higher‐order adaptive integration
Authors: Russo Raffaele , Chen Boyang
Published: July 2020

Cohesive element (CE) is a well‐established finite element for fracture, widely used for the modeling of delamination in composites. However, an extremely fine mesh is usually needed to resolve the cohesive zone, making CE‐based delamination analysis computationally prohibitive for applications beyond the scale of lab coupons. In this work, a new CE‐based method of modeling delamination in composites is proposed to overcome this cohesive zone limit on the mesh density. The proposed method makes use of slender structural elements for the plies, a compatible formulation with adaptive higher‐order integration for the CEs, and the corotational formulation for geometrically nonlinear analysis. The proposed method is verified and validated on the classical benchmark problems of Mode I, II, mixed‐mode delamination, a buckling‐induced delamination problem and a double‐delamination problem. The results show that elements much larger than the cohesive zone length can be used while retaining accuracy.
Matrix‐free crosshole elliptical‐anisotropy tomography: parametrization analysis and ground‐penetrating radar applications in carbonates
Authors: Salcedo Marco , Garambois Stéphane , Le Bouteiller Philippe , Li Yubing , Sénéchal Guy , Danquigny Charles , Virieux Jean
Published: July 2020

A novel traveltime tomographic approach is applied to anisotropic media, limited to 2D geometry at present. A general anisotropic Eikonal solver based on a discontinuous Galerkin method is combined with an efficient adjoint formulation for multiparameter least‐squares inversion. This new approach is tested considering synthetic crosshole ground‐penetrating radar data. The configuration of the ground‐penetrating radar survey is inspired by a real experiment done on layered carbonate media disturbed by the presence of a deep gallery, which induces a localized high‐electromagnetic contrast. This made it possible to define a well‐adapted general workflow in this context. We notably show that, under the elliptical anisotropic assumption, the parametrization based on vertical and horizontal velocities provides less biased results than those obtained by considering the vertical velocity and the relevant Thomsen parameter . The initial vertical and horizontal velocity models are identical and built from an isotropic inversion. The presence of the high‐contrast gallery generates a weak diffraction pattern, which is taken into account in our tomography approach. It also creates potential artefacts due to the model discretization, which are mitigated by a model regularization term within the definition of the misfit function. This general workflow is then applied to the real experiment dataset. The vertical and horizontal velocity images provide similar structures as those previously obtained by isotropic full waveform inversion, complemented by an image of a rather weak elliptical anisotropy.
Distributed adaptive consensus tracking for uncertain high‐order nonlinear multiagent systems with event‐triggered communication
Authors: Long Jiang , Wang Wei , Huang Jiangshuai , Fan Huijin
Published: July 2020

This article investigates the distributed adaptive consensus tracking control problem for a class of high‐order nonlinear multiagent systems with unmodeled system dynamics, uncertain external disturbances, and event‐triggered communication. Under an undirected graph condition, a robust distributed adaptive consensus control scheme is proposed. To deal with the lumped system uncertainties involved in each agent, adaptive compensation techniques are adopted. Moreover, by designing a triggering condition for each agent, which only relies on individual states' changing rates, continuous monitoring of neighboring states can be avoided. It is shown that with the proposed control scheme, all the closed‐loop signals are globally uniformly bounded and all the agents' outputs can track the desired trajectory with adjustable tracking errors. Meanwhile, Zeno behavior is excluded in each agent.
Prediction on electrical resistivity of thin‐ply unidirectional composites considering electric tunnel effect
Authors: Zhang Jin‐Na , Wang Chao‐Yang , Guo Zoey , Zhou Ying‐Guo , Wu Hai‐Hong
Published: July 2020

This article presents a model for equivalent conductive paths to predict the resistivity of thin‐ply carbon fiber reinforced unidirectional laminate (UDL), which incorporates electric tunnel effect. A statistical method was used to calculate the effective intra‐laminar conductive contact ratio and the number of inter‐laminar conductive pathways. Resistivities of four samples with ply thickness varying from 0.02 to 0.1 mm were calculated. A detailed comparison between the predicted and measured resistivities in the longitudinal, transverse and thickness directions validates the present model, which reveals the influence of ply thickness on the resistivity of the samples. Analysis of the model indicates that the resistivity of UDLs in the fiber direction is mainly dependent on the volume fraction, and the resistivities in their transverse and thickness directions are related to both the volume fraction of fibers and the microstructure of UDLs.
The connective eccentricity index of graphs and its applications to octane isomers and benzenoid hydrocarbons
Authors: Wang Guangfu , Yan Lixia , Zaman Shahid , Zhang Minjie
Published: July 2020

The connective eccentricity index (CEI) of a graph G is defined as , where εG(.) denotes the eccentricity of the corresponding vertex. The CEI obligates an influential ability, which is due to its estimating pharmaceutical properties. In this paper, we first characterize the extremal graphs with respect to the CEI among k‐connected graphs (k‐connected bipartite graphs) with a given diameter. Then, the sharp upper bound on the CEI of graphs with given connectivity and minimum degree (independence number) is determined. Finally, we calculate the CEI of two sets of molecular graphs: octane isomers and benzenoid hydrocarbons. We compare their CEI with some other distance‐based topological indices through their correlations with the chemical properties. The linear model for the CEI is better than or as good as the models corresponding to the other distance‐based indices.
Consensus problem for continuous‐time multiagent systems with nonconvex control input and velocity constraints
Authors: Duan Mengmeng , Lin Peng , Yang Chunhua
Published: July 2020

In this work, a consensus problem with nonconvex control input and velocity constraints is studied for continuous‐time multiagent systems. In order to solve this problem, a fully distributed nonlinear algorithm is provided and an analysis approach is proposed based on the contraction property of an equivalent time‐varying system after a model transformation. It is shown that consensus can be achieved under the condition that there exists a directed spanning tree in the union of the communication graphs in each certain time interval. A numerical simulation is provided to show the obtained result.
Two‐layer distributed formation‐containment control strategy for linear swarm systems: Algorithm and experiments
Authors: Hu Junyan , Bhowmick Parijat , Lanzon Alexander
Published: July 2020

This article addresses the problem of designing a two‐layer distributed formation‐containment control scheme for linear time‐invariant swarm systems with directed communication topology, where the states of the leaders attain a prespecified time‐varying/stationary formation and the states of the followers converge into the convex hull spanned by the states of the leaders. To achieve formation‐containment, a set of distributed control protocols is developed utilizing the neighboring state information, which enables the proposed scheme operate without using global information about the entire interaction topology. The conditions to achieve formation‐containment are suggested and a theoretical proof of the proposed scheme is also derived exploiting the Lyapunov stability approach. An algorithm is written to provide systematic guidelines on how to implement the control protocols in practice. It is argued that the consensus problem, formation tracking problem, and containment control problem can all be viewed as special cases of formation‐containment. A simulation case study has been presented to demonstrate the usefulness and effectiveness of the proposed scheme and moreover, lab‐based hardware experiments involving networked mobile robots were performed to test the feasibility of the scheme in real‐time implementation.
Methanation Performance of Unsupported MoP Catalysts Prepared with Phytic Acid under Low H2/CO
Authors: Wang Baowei , Wang Yu , Zhao Jun , Li Zhenhua , Xu Yan , Ma Xinbin
Published: July 2020

In this paper, using phytic acid as the precursor, the effects of the reduction temperature and post‐treatment conditions on the methanation performance of unsupported MoP catalysts were investigated. The synthesis mechanism and structure‐activity relationship of the catalyst were investigated by correlation characterization, such as N2 adsorption‐desorption, XRD, Raman analysis, element analysis and XPS. At the reduction temperature of 650 °C, MoP catalysts showed the higher methanation activity due to its smaller crystallite size and large specific surface area. After H2 post‐treatment at 750 °C, the CO conversion increased by 16.2% because of the higher specific surface area and lower contents of the carbon and phosphorus species in MoP‐750‐H. The MoP‐750‐H catalysts show good stability without H2S. The sulfur‐resistant methanation tests indicated that the inactivation of the catalysts was more serious with the higher H2S concentration, due to the sulfidation from MoP to MoS2.
Student Movements and Autocracies in Africa
Authors: Rukato Wadeisor
Published: July 2020

This chapter offers a historical mapping of student movements and youth-led protests against autocracies in African countries. It focuses on student movements in Senegal, Tanzania and Sudan from the period before independence to the present day to consider the intersections of youth-hood, power, higher education institutions and the state in each of these cases. It highlight the various continuities and disjunctures in the ways that university student movements have challenged autocracy to consider how “successful” student protests can be in shifting political bases of power.
Achronal averaged null energy condition for extremal horizons and (A)dS
Authors: Rosso Felipe
Published: July 2020

Abstract

We prove the achronal averaged null energy condition for general quantum field theories in the near horizon geometry of spherical extremal black holes (i.e. AdS2× Sd−2), de Sitter and anti-de Sitter. The derivation follows from monotonicity of relative entropy after computing the modular hamiltonian of a null deformed region. For incomplete (but maximally extended) achronal null geodesics in AdS2× Sd−2, we prove the positivity of a different light-ray operator for arbitrary CFTs. This agrees with a constraint recently derived for the Lorentzian cylinder.
Twisted form hierarchies, Killing-Yano equations and supersymmetric backgrounds
Authors: Papadopoulos G.
Published: July 2020

Abstract

We show that the Killing spinor equations of all supergravity theories which may include higher order corrections on a (r,s)-signature spacetime are associated with twisted covariant form hierarchies. These hierarchies are characterized by a connection on the space of forms which may not be degree preserving. As a consequence we demonstrate that the form Killing spinor bi-linears of all supersymmetric backgrounds satisfy a suitable generalization of conformal Killing-Yano equation with respect to this connection. To illustrate the general proof the twisted covariant form hierarchies of some supergravity theories in 4, 5, 6, 10 and 11 dimensions are also presented.
Hybrid TRUS/CT with optical tracking for target delineation in image-guided adaptive brachytherapy for cervical cancer
Authors: Smet Stéphanie , Nesvacil Nicole , Knoth Johannes , Sturdza Alina , Najjari-Jamal Dina , Jelinek Filip , Kronreif Gernot , Pötter Richard , Widder Joachim , Kirisits Christian , Schmid Maximilian P.
Published: July 2020

Objective

To prospectively compare the interobserver variability of combined transrectal ultrasound (TRUS)/computed tomography (CT)- vs. CT only- vs. magnetic resonance imaging (MRI) only-based contouring of the high-risk clinical target volume (CTVHR) in image-guided adaptive brachytherapy (IGABT) for locally advanced cervical cancer (LACC).

Methods

Five patients with LACC (FIGO stages IIb–IVa) treated with radiochemotherapy and IGABT were included. CT, TRUS, and T2-weighted MRI images were performed after brachytherapy applicator insertion. 3D-TRUS image acquisition was performed with a customized ultrasound stepper device and software. Automatic applicator reconstruction using optical tracking was performed in the TRUS dataset and TRUS and CT images were fused with rigid image registration with the applicator as reference structure. The CTVHR (based on the GEC-ESTRO recommendations) was contoured by five investigators on the three modalities (CTVHR_CT, CTVHR_TRUS-CT, and CTVHR_MRI). A consensus reference CTVHR_MRI (MRIref) was defined for each patient. Descriptive statistics and overlap measures were calculated using RTslicer (SlicerRT Community and Percutaneous Surgery Laboratory, Queen’s University, Canada), comparing contours of every observer with one another and with the MRIref.

Results

The interobserver coefficient of variation was 0.18 ± 0.05 for CT, 0.10 ± 0.04 for TRUS-CT, and 0.07 ± 0.03 for MRI. Interobserver concordance in relation to the MRIref expressed by the generalized conformity index was 0.75 ± 0.04 for MRI, 0.51 ± 0.10 for TRUS-CT, and 0.48 ± 0.06 for CT. The mean CTVHR_CT volume of all observers was 71% larger than the MRIref volume, whereas the mean CTVHR_TRUS-CT volume was 15% larger.

Conclusion

Hybrid TRUS-CT as an imaging modality for contouring the CTVHR in IGABT for LACC is feasible and reproducible among multiple observers. TRUS-CT substantially reduces overestimation of the CTVHR volume of CT alone while maintaining similar interobserver variability.
Dose–volume parameters of MRI-based active bone marrow predict hematologic toxicity of chemoradiotherapy for rectal cancer
Authors: Kuncman Łukasz , Stawiski Konrad , Masłowski Michał , Kucharz Jakub , Fijuth Jacek
Published: July 2020

Purpose

Magnetic resonance imaging (MRI) is routinely used for locoregional staging of rectal cancer and offers promise for the prediction of hematologic toxicity. The present study compares the clinical utility of MRI-based active bone marrow (BMact) delineation with that of CT-based bone marrow total (BMtot) delineation for predicting hematologic toxicity.

Methods

A prospective cohort study was performed. Eligible patients had stage II/III rectal cancer and qualified for preoperative chemoradiotherapy. The BMact areas on T1-weighted MRI were contoured. The impact of the dose–volume parameters of BMact/BMtot and clinical data on hematologic toxicity were assessed. Basic endpoints were the occurrence of grade 3/4 hematologic toxicity and peripheral blood parameters reaching a nadir. Linear regression models were generated for the nadirs and receiver operating characteristic (ROC) curves for the occurrence of grade 3/4 hematologic toxicity.

Results

Thirty-five patients were enrolled. Women presented higher dose–volume parameters of BMact, BMtot, and lymphocyte nadir (ALCnadir%) than men. Models for the prediction of ALCnadir% (V5-V20BMtot, V5-V30BMact) and platelet nadir (PLTnadir%; V5-V10BMtot, V5-V20BMact) were statistically significant. In the ROC curves, a baseline lymphocyte level of 1.81 × 103/ml was adopted as the cutoff for predicting grade 3/4 lymphopenia, with specificity of 77.8% and sensitivity of 73.1%. The multivariate linear regression model for ALCnadir% had R2 = 0.53, p = 0.038. In the tenth step of selection, V5BMact (p = 0.002) and gender (p = 0.019) remained. The multivariate linear regression model for PLTnadir% had R2 = 0.20, p = 0.34. In the sixth step of selection, V15BMact remained (p = 0.026).

Conclusion

The dose–volume parameters of BMact serve as better predictors of ALCnadir% and PLTnadir% than BMtot.
Reduced accuracy of MRI deep grey matter segmentation in multiple sclerosis: an evaluation of four automated methods against manual reference segmentations in a multi-center cohort
Authors: de Sitter Alexandra , Verhoeven Tom , Burggraaff Jessica , Liu Yaou , Simoes Jorge , Ruggieri Serena , Palotai Miklos , Brouwer Iman , Versteeg Adriaan , Wottschel Viktor , Ropele Stefan , Rocca Mara A. , Gasperini Claudio , Gallo Antonio , Yiannakas Marios C. , Rovira Alex , Enzinger Christian , Filippi Massimo , De Stefano Nicola , Kappos Ludwig , Frederiksen Jette L. , Uitdehaag Bernard M. J. , Barkhof Frederik , Guttmann Charles R. G. , Vrenken Hugo ,   the MAGNIMS Study Group
Published: July 2020

Background

Deep grey matter (DGM) atrophy in multiple sclerosis (MS) and its relation to cognitive and clinical decline requires accurate measurements. MS pathology may deteriorate the performance of automated segmentation methods. Accuracy of DGM segmentation methods is compared between MS and controls, and the relation of performance with lesions and atrophy is studied.

Methods

On images of 21 MS subjects and 11 controls, three raters manually outlined caudate nucleus, putamen and thalamus; outlines were combined by majority voting. FSL-FIRST, FreeSurfer, Geodesic Information Flow and volBrain were evaluated. Performance was evaluated volumetrically (intra-class correlation coefficient (ICC)) and spatially (Dice similarity coefficient (DSC)). Spearman's correlations of DSC with global and local lesion volume, structure of interest volume (ROIV), and normalized brain volume (NBV) were assessed.

Results

ICC with manual volumes was mostly good and spatial agreement was high. MS exhibited significantly lower DSC than controls for thalamus and putamen. For some combinations of structure and method, DSC correlated negatively with lesion volume or positively with NBV or ROIV. Lesion-filling did not substantially change segmentations.

Conclusions

Automated methods have impaired performance in patients. Performance generally deteriorated with higher lesion volume and lower NBV and ROIV, suggesting that these may contribute to the impaired performance.
Extensor tendon ruptures in rheumatoid wrists
Authors: Biehl C. , Rupp M. , Kern S. , Heiss C. , ElKhassawna T. , Szalay G.
Published: July 2020

Background and aims

Rheumatoid arthritis is a chronic inflammatory disease. The associated involvement of hands and tendons is over 90% and impairs overall function. In the course of the disease, the joints are often operated on. During this operation, ruptures of the extensor tendons are found by chance without the patients noticing them. The aim of this retrospective study is the prevalence of extensor tendon rupture. Which tendon is destroyed most frequently? How can the functional outcome be measured after reconstruction?

Materials and methods

From 1572 operations on rheumatoid wrists, 61 extensor tendon ruptures were identified in 41 patients. The average time between the first rheumatic symptoms of the hand and surgery was 6.4 years. The average duration of RA was 7.8 years. 26 patients with 27 tendon reconstructions were included in the follow-up with an average postoperative duration of 4.6 years (3 to 14.2 years).

Results

Extensor tendons ruptures typically occurred at mechanically stressed sites. The most frequent rupture was found in the extensor pollicis longus tendon (21 tendons), followed by the small finger extensor tendon (14 tendons). A transfer was performed on 7 tendons. Fifty-five tendon lesions were sutured at other intact tendons. Free grafts were not used. The results in Clayton and QuickDASH scores were significantly different. Functional improvement was consistent with the results of tendon reconstructions in healthy control groups.

Conclusion

In rheumatoid patients, a rupture of an extensor tendon must be expected at 4%. Patients tolerate and compensate this damage for a long time. The function of the hand including the tendon function is the most important factor in assessing the success of the operation. The subjective patient acceptance depends on the progress of the underlying disease, postoperative care (ergotherapy, physiotherapy, orthosis) and the patients' demands.
Evoking emotions in virtual reality: schema activation via a freeze-frame stimulus
Authors: Lipp Natalia , Dużmańska-Misiarczyk Natalia , Strojny Agnieszka , Strojny Paweł
Published: July 2020

Virtual reality can be used for educational purposes, particularly in demanding professions such as firefighting. Such virtual training may be useful for preparing trainees for distress, fear, or frustration experienced during real rescue operations. Evoking cognitive schemas, especially of other people, during training appears to be crucial as well, as the greatest stressors in the firefighting profession are social. Based on interviews with firefighters, two types of people (children and young women) were chosen as stimuli in the research design. In an experimental study with three iterations, the stimuli designed to evoke the schema of a significant other were implemented in a virtual reality simulator to evoke a cognitive schema in firefighters through emotions (positive and negative) and several dimensions of stress. The first iteration of the study did not yield expected results, as the stimulus (a child’s toy) was not as suggestive and vivid as it was expected. In the second attempt, the stimulus was improved and evoked feelings of challenge, harm, and loss in the participants. In the third iteration, the stimulus was changed once more (to a white dress) and this time it evoked negative emotions of fear, anger, guilt, and sadness. However, after correcting for multiple comparisons, only results regarding emotional response remained statistically significant. The results are discussed in light of cognitive schemas’ activation, and perspectives for further research in this scope are proposed. Due to research outcomes, the issues of manipulation checks in experimental psychology and limitations of the VR technology are taken into consideration.
Submucosal gland neoplasms of the esophagus: an update and review
Authors: Nie Ling , Li Wei , Xue Liyan , Wang Lin , Shen Yonghua , Fan Xiangshan
Published: July 2020

Submucosal glands (SMGs) present throughout human esophagus with clusters at either the upper third or lower third of the organ. SMGs tend to atrophy with age, and neoplasms arising in these glands are rare. In order to bring convenience to diagnosis, we summarize the histopathologic characteristics of all esophageal submucosal gland tumors (SGTs). Due to the morphological similarity, the nomenclature of salivary tumors is adopted for SGTs. However, there is great confusion about the definition and histogenesis of these tumors, especially the malignant subtypes. In the literature, esophageal mucoepidermoid carcinoma and adenoid cystic carcinoma usually adjoin the surface squamous epithelium and coexist with intraepithelial neoplasia or invasive squamous cell carcinoma (SCC). In addition, the typical gene alterations of salivary tumors have not been reported in these SGTs. Therefore, we propose to apply stringent diagnostic criteria to esophageal SGTs so as to exclude mimickers that are SCCs with various degree of SMG differentiation.