bluuebunny/crossref_metadata_2025 huggingface dataset:
Divergence and hybridization in the desert plant Reaumuria soongarica
Authors: Shi Yong , Yan Xia , Yin Heng‐Xia , Qian Chao‐Ju , Fan Xing‐Ke , Yin Xiao‐Yue , Chang Yu‐Xiao , Zhang Cheng‐Jun , Ma Xiao‐Fei
Published: March 2019

Speciation is widely accepted to be a complex and continuous process. Due to complicated evolutionary histories, desert plants are ideal model systems to understand the process of speciation along a continuum. Here, we elucidate the evolutionary history of Reaumuria soongarica (Pall.) Maxim., a typical desert plant that is wildly distributed across arid central Asia. Based on variation patterns present at nine nuclear loci in 325 individuals (representing 41 populations), we examined the demographic history, patterns of gene flow, and degree of ecological differentiation among wild R. soongarica. Our findings indicate that genetic divergence between the ancient western and eastern lineages of R. soongarica occurred approximately 0.714 Mya, probably due to the Kunlun–Yellow River tectonic movement and the Naynayxungla glaciation. Later, multiple hybridization events between the western and eastern lineages that took place between 0.287 and 0.543 Mya, and which might have been triggered by the asynchronous historical expansion of the western and eastern deserts, contributed to the formation of a hybrid northern lineage. Moreover, despite continuing gene flow into this population from its progenitors, the northern lineage maintained its genetic boundary by ecological differentiation. The northern lineage could be an incipient species, and provides an opportunity to study the continuous process of speciation. This study suggests that two opposite evolutionary forces, divergence and hybridization, coexisting in the continuous speciation of the desert plant R. soongarica in a short time. Moreover, we provide evidence that this continuous speciation process is affected by geological events, climatic change, and ecological differentiation.
Screening for sleep‐disordered breathing with Pediatric Sleep Questionnaire in children with underlying conditions
Authors: Pabary Rishi , Goubau Christophe , Russo Kylie , Laverty Aidan , Abel François , Samuels Martin
Published: March 2019

The Pediatric Sleep Questionnaire described by Chervin et al. (Sleep Medicine, 2000, 1, 21–32) was originally validated for children with obstructive sleep apnoea syndrome but without other disorders. The aim of our study was to check the applicability of this questionnaire in children with underlying chronic medical conditions. Children aged 2–18 years who underwent a diagnostic sleep study at Great Ormond Street Hospital were recruited over a 10‐month period. The Pediatric Sleep Questionnaire completed by their parents and cardiorespiratory polygraphy were scored. Sensitivities and specificities of the Pediatric Sleep Questionnaire were calculated using a Pediatric Sleep Questionnaire score of 0.33 as being indicative of sleep‐disordered breathing. A total of 561 patients were reviewed. Neuromuscular disorders (n = 108), craniofacial anomalies (n = 58) and the obstructive sleep apnea syndrome control group (n = 155) were best represented. The sensitivity for patients with isolated obstructive sleep apnoea syndrome was 76.5% when using an apnoea–hypopnoea index ≥ 5, but this was much lower when looking at specific sub‐groups such as neuromuscular patients (25%) or patients with Trisomy 21 (36.7%). Sensitivities remained unchanged for patients with obstructive sleep apnoea syndrome (77.3%) when an apnoea–hypopnoea index of ≥ 1 was used, but improved for neuromuscular disorders sub‐groups (36.7%) and Trisomy 21 (84%). In conclusion, the Pediatric Sleep Questionnaire is not a good screening tool for obstructive sleep apnoea syndrome in children with complex underlying disorders when a cut‐off apnoea–hypopnoea index of ≥ 5 is used, and it cannot replace cardiorespiratory polygraphy recording.
Testing for Change in Long‐Memory Stochastic Volatility Time Series
Authors: Betken Annika , Kulik Rafał
Published: March 2019

In this article, change‐point problems for long‐memory stochastic volatility (LMSV) models are considered. A general testing problem which includes various alternative hypotheses is discussed. Under the hypothesis of stationarity the limiting behavior of CUSUM‐ and Wilcoxon‐type test statistics is derived. In this context, a limit theorem for the two‐parameter empirical process of LMSV time series is proved. In particular, it is shown that the asymptotic distribution of CUSUM test statistics may not be affected by long memory, unlike Wilcoxon test statistics which are typically influenced by long‐range dependence. To avoid the estimation of nuisance parameters in applications, the usage of self‐normalized test statistics is proposed. The theoretical results are accompanied by an analysis of Standard & Poor's 500 daily closing indices with respect to structural changes and by simulation studies which characterize the finite sample behavior of the considered testing procedures when testing for changes in mean and in variance.
Investigating Legal Consciousness through the Technical Work of Elite Lawyers: A Case Study on Tax Avoidance
Authors: Cornut St-Pierre Pascale
Published: March 2019

Since the 1990s, legal consciousness has been amply used by sociolegal scholars to better understand the everyday lives of ordinary people, with a strong focus on vulnerable or impoverished people. This article argues that legal consciousness, with some methodological adjustments, could lend itself to the study of the rich and powerful by investigating both the technical work of their lawyers and how that work shapes our broader legal culture. To illustrate this point, this article takes tax avoidance as a case study. Drawing on materials revealed by a recent tax scandal, it suggests that current difficulty in tackling the problem of tax avoidance rests on uneven access to the cultural repertoires related to legal technique and legal innovation, which fosters the tax-avoidance narrative's ambiguity.
The relationship between coronary artery disease and cardiovascular events early after liver transplantation
Authors: Patel Samarth S. , Lin Fei‐Pi , Rodriguez Viviana A. , Bhati Chandra , John Binu V. , Pence Taylor , Siddiqui Mohammad B. , Sima Adam P. , Abbate Antonio , Reichman Trevor , Siddiqui Mohammad S.
Published: March 2019

Background & Aims

Cardiovascular complications are major contributors to mortality at liver transplantation (LT). However, the impact of coronary artery disease (CAD) on these complications is not well‐understood as the literature is limited by non‐invasive assessment of CAD, which is suboptimal in patients with cirrhosis. Thus, the current study evaluated cardiovascular events at LT stratified according to the presence and severity of CAD quantified on coronary angiography.

Methods

All patients who had LT from January 2010 to January 2017 were evaluated (N = 348), but analysis was restricted to patients who had coronary angiography prior to LT (N = 283). Protocol coronary angiography was performed in all patients’ ages >50 years, history of CAD, abnormal cardiac stress test or risk factors for CAD. The primary outcome was a cardiovascular composite outcome including myocardial infraction (MI), cardiac arrest, stroke, cardiac death, heart failure or arrhythmia occurring within 4 weeks after LT.

Results

CAD was present in 92(32.5%) patients and 32(11.3%) had obstructive CAD. During the study period, 72(25.4%) patients met the primary cardiovascular outcome, the most common being arrhythmia (N = 59 or 20.8%). Non‐ST elevation MI occurred in 11(3.9%) of patients. A total of 10 deaths (3.5%) occurred, of which 6(2.1%) were attributable to cardiac death. There was no evidence of a relationship between the presence and severity of CAD and composite cardiovascular events. In multiple regression modelling, only diabetes [OR 2.62, 95%CI (1.49, 4.64), P < 0.001] was associated with the likelihood of having a cardiovascular event.

Conclusion

Cardiovascular disease mortality is the most important contributor of early mortality after LT but is not related to the severity of CAD.
Periodic strategies in optimal execution with multiplicative price impact
Authors: Hernández‐Hernández Daniel , Moreno‐Franco Harold A. , Pérez José‐Luis
Published: March 2019

We study the optimal execution problem with multiplicative price impact in algorithmic trading, when an agent holds an initial position of shares of a financial asset. The interselling decision times are modeled by the arrival times of a Poisson process. The criterion to be optimized consists in maximizing the expected net present value of the gains of the agent, and it is proved that an optimal strategy has a barrier form, depending only on the number of shares left and the level of the asset price.
Siderophile element characteristics of acapulcoite–lodranites and winonaites: Implications for the early differentiation processes of their parent bodies
Authors: Hidaka Yoshihiro , Shirai Naoki , Yamaguchi Akira , Ebihara Mitsuru
Published: March 2019

We have studied magnetic fractions of five acapulcoites, three lodranites, and two winonaites to investigate chemical compositions of their precursor materials and metallic partial melting processes occurring on their parent bodies. One winonaite metal is similar in composition to low Au, low Ni IAB iron subgroup, indicating genetic relationship between them. Magnetic fractions of chondrule‐bearing acapulcoite and winonaite have intermediate chemical compositions of metals between H chondrites and EL chondrites. This fact indicates that the precursor materials of acapulcoite–lodranites and winonaites were similar to H and/or EL chondrites in chemical compositions. Magnetic fractions in acapulcoite–lodranites have a large variety of chemical compositions. Most of them show enrichments of W, Re, Ir, Pt, Mo, and Rh, and one of them shows clear depletion in Re and Ir relative to those of chondrule‐bearing acapulcoite. Chemical compositional variations among acapulcoite–lodranite metals cannot be explained by a single Fe‐Ni‐S partial melting event, but a two‐step partial melting model can explain it.
Neurologic findings are the sole manifestations of a patient with cerebrotendinous xanthomatosis
Authors: Yamashita Shoko , Hirano Makito , Yanagimoto Satoshi , Okazaki Masahiro , Sakai Norio , Kusunoki Susumu
Published: March 2019

Cerebrotendinous xanthomatosis (CTX), a treatable autosomal recessive lipid‐storage disease, is caused by mutations in the CYP27A1 gene. Clinical manifestations include progressive neurologic dysfunction, tendon xanthoma, cataracts, and diarrhea. Patients with CTX generally have several non‐neurologic signs and symptoms, and thus, patients with only neurologic findings have been rarely reported. We here report a patient who solely had neurologic findings with compound heterozygous mutations in the CYP27A1 gene.
A critical analysis of articles using a Gadamerian based research method
Authors: Fleming Valerie , Robb Yvonne
Published: March 2019

It is over 20 years since Michael Crotty's groundbreaking critique of phenomenological research in nursing. However, rather than entering into the acrimonious discussions that followed, we developed a research method that we believed translated Gadamer's philosophy into the world of empirical research. Fundamental to that work was our differentiation of hermeneutics from phenomenology. The aim of the present paper was to provide a critical analysis of the citations from publication in 2003 until the end of 2017. We identified 402 citations of which 362 were included. One hundred and sixty‐three articles mentioned the article in passing, usually in a list of authors who had discussed hermeneutics. Sixteen citations misrepresented the method mainly claiming that we discussed a method for hermeneutic phenomenology (or phenomenological hermeneutics). Of the 117 citations that partially used the method, the main focus was the four steps of data analysis. Sixty studies used our method in totality although they derive from varying philosophical standpoints. Disappointingly, there has been little critique of our Gadamerian research method. For health disciplines to truly make progress in the academic stage, it is vital that we engage in with critique, some of which will come through open and honest reflexive engagement with our topics.
Willingness to receive influenza vaccination during pregnancy and associated factors among pregnant women in Taiwan
Authors: Chang Ya‐Wen , Tsai Shiow‐Meei , Lin Pao‐Chen , Chou Fan‐Hao
Published: March 2019

Objective

This study was aimed to assess the willingness to receive prenatal influenza vaccine and explore its associated factors among pregnant women in Taiwan.

Design and Sample

The study population included pregnant women who received prenatal care from five private hospitals/clinics during 2017–2018 influenza season.

Measurements

Collected data, including demographics, health‐relevant factors, as well as knowledge and attitudes regarding influenza and its vaccine, were analyzed using chi‐square tests, Fisher's exact test, and multivariate logistic regression analysis.

Results

A total of 498 pregnant women completed the questionnaires, 321 (64.5%) intended to receive prenatal influenza vaccine. Among those who were unwilling to be vaccinated, most (88%) had concerns about the adverse events of the vaccine. Four factors were independently associated with willingness, including hospital/clinic (aOR=6.57, 95% CI=1.96–22.04), previous influenza vaccination history (aOR=9.44, 95% CI=5.63–15.83), knowledge (aOR=2.64, 95% CI=1.25–5.55) about, and attitude (aOR=5.99, 95% CI=2.40–14.92) toward influenza vaccination.

Conclusions

Pregnant women with insufficient knowledge, negative attitudes, or no experience of influenza vaccination, and in remote areas were less willing to receive maternal influenza vaccine. The adverse events and uncertainty regarding the safety of vaccines were the most important factors. The health‐care providers should promote or explain risks and benefits of maternal influenza vaccination during prenatal care or outpatient consultation.
Large lateralized EDAN‐like brain potentials in a gaze‐shift detection task
Authors: Kirk Driller K. , Stephani T. , Dimigen O. , Sommer W.
Published: March 2019

Attentional cueing tasks using gaze direction as spatial cues have sometimes yielded an early directing attention negativity (EDAN) component in the ERP, presumably reflecting the initial orienting toward the cued location. However, other studies have failed to identify an EDAN component for gaze cues, yielding an inconsistent picture. In the present study, we re‐examined the EDAN to gaze cueing, using a continuous task where the specific direction of the gaze changes was task irrelevant. Face stimuli changed gaze direction several times during each trial between direct, left‐, and right‐averted positions. Participants counted the number of gaze shifts during the trial. Results showed an unusually large EDAN‐like ERP asymmetry at posterior scalp sites that was of similar amplitude for large and small gaze shifts into the periphery. Shifts from an averted position toward a direct gaze elicited a qualitatively similar but smaller effect than shifts into the periphery. Together, these findings shed new light on gaze‐elicited spatial attention as they indicate a reflexive attention orienting, following the direction of gaze motion, even when the gaze direction itself is irrelevant for the task.
Changes in physical activity during hospital admission for chronic respiratory disease
Authors: Orme Mark W. , Harvey‐Dunstan Theresa C. , Boral Ismet , Chaplin Emma J.L. , Hussain S. Fayyaz , Morgan Mike D.L. , Steiner Michael C. , Singh Sally J. , Greening Neil J.
Published: March 2019

Background and objective

Establishing the amount of inpatient physical activity (PA) undertaken by individuals hospitalized for chronic respiratory disease is needed to inform interventions. This observational study investigated whether PA changes when a person is an inpatient, how long is required to obtain representative PA measures and whether PA varies within a day and between patients of differing lengths of stay.

Methods

A total of 389 participants were recruited as early as possible into their hospitalization. Patients wore a PA monitor from recruitment until discharge. Step count was extracted for a range of wear time criteria. Single‐day intraclass correlation coefficients (ICC) were calculated, with an ICC ≥ 0.80 deemed acceptable.

Results

PA data were available for 259 participants. No changes in daily step count were observed during the inpatient stay (586 (95% CI: 427–744) vs 652 (95% CI: 493–812) steps/day for day 2 and 7, respectively). ICC across all wear time criteria were > 0.80. The most stringent wear time criterion, retaining 80% of the sample, was ≥11 h on ≥1 day. More steps were taken during the morning and afternoon than overnight and evening. After controlling for the Medical Research Council (MRC) grade or oxygen use, there was no difference in step count between patients admitted for 2–3 days (short stay) and those admitted for 7–14 days (long stay).

Conclusion

Patients move little during their hospitalization, and inpatient PA did not increase during their stay. A wear time criterion of 11 waking hours on any single day was representative of the entire admission whilst retaining an acceptable proportion of the initial sample size. Patients may need encouragement to move more during their hospital stay.
On the optimal focusing of solitons and breathers in long‐wave models
Authors: Slunyaev Alexey
Published: March 2019

Conditions of optimal (synchronized) collisions of any number of solitons and breathers are studied within the framework of the Gardner equation (GE) with positive cubic nonlinearity, which in the limits of small and large amplitudes tends to other long‐wave models, the classic and the modified Korteweg–de Vries equations. The local solution for an isolated soliton or breather within the GE is obtained. The wave amplitude in the focal point is calculated exactly. It exhibits a linear superposition of partial amplitudes of the solitons and breathers. The crucial role of the choice of proper soliton polarities and breather phases on the cumulative wave amplitude in the focal point is demonstrated. Solitons are most synchronized when they have alternating polarities. The straightforward link to the problem of synchronization of envelope solitons and breathers in the focusing nonlinear Schrödinger equation is discussed (then breathers correspond to envelope solitons propagating above a condensate).
High‐resolution national land use scenarios under a shrinking population in Japan
Authors: Ohashi Haruka , Fukasawa Keita , Ariga Toshinori , Matsui Tetsuya , Hijioka Yasuaki
Published: March 2019

In sharp contrast with the global trend in population growth, certain developed countries are expected to experience rapid national population declines. Considering future land use scenarios that include depopulation is necessary to evaluate changes in ecosystem services that affect human well‐being and to facilitate comprehensive strategies for balancing rural and urban development. In this study, we applied a population‐projection‐assimilated predictive land use modeling (PPAP‐LM) approach, in which a spatially explicit population projection was incorporated as a predictor in a land use model. To analyze the effects of future population distributions on land use, we developed models for five land use types and generated projections for two scenarios (centralization and decentralization) under a shrinking population in Japan during 2015–2050. Our results suggested that population centralization promotes the compaction of built‐up areas and the expansion of forest and wastelands, while population decentralization contributes to the maintenance of a mixture of forest and cultivated land.
Qualification Requirements Design for Neutron Absorber Plate for Spent Fuel Racks in Domestic Nuclear Power Plants
Authors: Shi You , Ning Dong , Yang Yi-zhong
Published: March 2019

Boron carbide (B4C) particle-reinforced aluminum matrix composite is the key material for use as neutron absorber plate in fuel storage applications for Generation III advanced passive nuclear power plants in China. This material has once depended upon importing with various restrictions so that it has meaningful practical significance to realize the localized manufacturing for this material in China. More importantly, since it is the first time for this material to be used in domestic plant, particular care should be taken to assure the formal supplied products exhibit high stabilized and reliable service in domestic nuclear engineering. This paper initiates and proposes a principle design framework from technical view in qualification requirements for this material so as to guide the practical engineering application. Aiming at neutron absorber materials supplied under practical manufacturing condition in engineering delivery, the qualification requirements define B4C content, matrix chemistry, 10B isotope, bulk density, 10B areal density, mechanical property, and microstructure as key criteria for material performance. The uniformity assessment as to different locations of this material is also required from at least three lots of material. Only qualified material meeting all of the qualification requirements should proceed to be verified by lifetime testing such as irradiation, corrosion, and thermal aging testing. Systematic and comprehensive performance assessments and verification for process stabilization could be achieved through the above qualification. The long-term service for this neutron absorber material in reliable and safe way could be convincingly expected in spent fuel storage application in China.
Contraction Theory Approach to Disturbance Observer Based Filtered Backstepping Design
Authors: Rayguru M. M. , Kar I. N.
Published: March 2019

Various practical applications use filtered backstepping technique, which follows the same procedure as backstepping design but uses high gain filters to circumvent the analytical computation of derivatives. As a result, there exists a time-scale separation between the system dynamics and the fast filter dynamics. This paper proposes a new contraction theory-based technique to design a high gain disturbance observer-based filtered backstepping controller and to quantify the convergence bounds in terms of design parameters. The quantification of the bounds explicitly shows the dependency of the closed-loop performance on various parameters, which in turn provide more ways to tune the performance apart from reducing the magnitude of filter parameter. Unlike the existing results, the proposed approach relaxes the conservative restriction, required on the filter parameter to achieve a satisfactory closed loop performance. The efficacy of the proposed method is verified through simulation examples.
Dynamic Modeling and Simulation of a Spar Floating Offshore Wind Turbine With Consideration of the Rotor Speed Variations
Authors: Al-Solihat Mohammed Khair , Nahon Meyer , Behdinan Kamran
Published: March 2019

This paper presents a rigid multibody dynamic model to simulate the dynamic response of a spar floating offshore wind turbine (FOWT). The system consists of a spar floating platform, the moorings, the wind turbine tower, nacelle, and the rotor. The spar platform is modeled as a six degrees-of-freedom (6DOFs) rigid body subject to buoyancy, hydrodynamic and moorings loads. The wind turbine tower supports rigid nacelle and rotor at the tip. The rigid rotor is modeled as a disk spinning around its axis and subject to the aerodynamic load. The generator torque control law is incorporated into the system dynamics to capture the rotor spinning speed response when the turbine is operating below the rated wind speed. The equations of motions are derived using Lagrange's equation in terms of the platform quasi-coordinates and rotor spin speed. The external loads due to hydrostatics, hydrodynamics, and aerodynamics are formulated and incorporated into the equations of motion. The dynamic simulations of the spar FOWT are performed for three load cases to examine the system eigen frequencies, free decay response, and response to a combined wave and wind load. The results obtained from the present model are validated against their counterparts obtained from other simulation tools, namely, FAST, HAWC2, and Bladed, with excellent agreement. Finally, the influence of the rotor gyroscopic moment on the system dynamics is investigated.
Improvement of Corrosion Resistance of Dissimilar Welded Joints in VVER Secondary Circuit
Authors: Samek Petr , Chocholatý Ondřej , Čančura Zdeněk , Kříž Antonín
Published: March 2019

This article presents experimental program, focused on extending lifetime and operation reliability of dissimilar welded joints of austenitic and perlite steel in conditions of secondary circuit media of water–water power reactor (VVER) unit. The main purpose of this experimental program is to bring new possibilities of corrosion protection of dissimilar welded joints, which are threatened by corrosion and degradation processes. These degradation processes significantly affect their service life. Suitability and corrosion behavior of thermal-sprayed coatings were tested.
Experimental Investigation of Melt Coolability and Ablation Behavior of Oxidic Sacrificial Material at Prototypic Conditions in Scaled Down Core Catcher
Authors: Munot Samyak S. , V Ganesh , Kulkarni Parimal P. , Nayak Arun K.
Published: March 2019

To minimize the potential risk of design extension conditions (DEC) with core meltdown, some advanced reactors employ ex-vessel core catchers which stabilize and cool the corium for prolonged period by strategically flooding it. This paper describes the coolability of the melt pool and ablation process in a scaled down ex-vessel core catcher employing sacrificial material which reduces the specific volumetric heat, temperature, and density of the melt pool. To understand these phenomena, a simulated experiment was carried out. The experiment was performed by melting about 500 kg of corium simulant using thermite reaction at about 2500 °C. The bricks of oxidic sacrificial material were arranged in the core catcher vessel which was surrounded by a tank filled with water up to a certain level. After the time required for melt inversion, water was introduced to flood the test section from the top. The melt pool temperatures were monitored at various locations using “K” and “C” type thermocouples to obtain ablation depth at different elevations with time. The results show that the coolability of the molten pool in the presence of water for the present geometry is achievable with outside vessel temperatures not exceeding 100 °C. A ceramic stable crust was observed at the top surface of the melt pool, which prevented water ingression into the molten corium. The ablation rate was found to be maximum at the lower corners of the brick arrangement with the maximum value being 0.75 mm/s. An average rate of about 0.18 mm/s was obtained in the brick matrix.
Evaluation of Dump Tank Coolability in PHWRs During Late-Phase Severe Accident
Authors: Pandey Pradeep , Kulkarni Parimal P. , Nayak Arun , Prasad Sumit V.
Published: March 2019

In some of the older design of pressurized heavy water reactors (PHWRs), such as in Rajasthan Atomic Power Station (RAPS) and Madras Atomic Power Station (MAPS), in case of a severe accident, the debris/corium may cause failure of the dump port of calandria and relocate into the dump tank. The sensible and decay heat of debris/corium makes the heavy water in dump tank to boil off leaving the dry debris in dump tank. The dry debris remelt with time and the molten corium, thus, formed has the potential to breach the dump tank and move into the containment cavity, which is highly undesirable. Hence, as an accident management strategy, water is being flooded outside the dump tank using fire water hook-up lines to remove the heat from corium to cool and stabilize it and terminate the accident progression, similar to in vessel retention. However, the question is “is the molten corium coolable by this technique.” The coolability of the molten corium in dump tank as in the reactor is assessed by conducting experiments in a scaled facility using a simulant material having comparable thermophysical properties with that of corium. Melting of dry debris resting on dump tank bottom marks the beginning of the experimental investigation for present analysis. Decay heat is simulated by a set of immersed heaters inside the melt. Temperature profiles at different locations in dump tank and in the melt pool are obtained as a function of time to demonstrate the coolability with decay heat. Large temperature gradient is observed within the corium, involving high melt center temperature and low tank wall temperature suggesting formation of crust which insulates the dump tank wall from hot corium.
NIH queries on foreign ties rattle universities
Authors: Mervis Jeffrey
Published: March 2019

Letters singling out faculty who may not have disclosed links could chill collaborations.
Did Black Death strike sub-Saharan Africa?
Authors: Wade Lizzie
Published: March 2019

An interdisciplinary cadre of researchers suggests medieval plague transformed societies.
University of California takes a stand on open access
Authors: Fox Alex , Brainard Jeffrey
Published: March 2019

University rejects Elsevier's journal subscriptions offer.
Direct stimulation of NADP
+
synthesis through Akt-mediated phosphorylation of NAD kinase
Authors: Hoxhaj Gerta , Ben-Sahra Issam , Lockwood Sophie E. , Timson Rebecca C. , Byles Vanessa , Henning Graham T. , Gao Peng , Selfors Laura M. , Asara John M. , Manning Brendan D.
Published: March 2019

Akt produces reducing power

The protein kinase Akt provides a link from growth factors to the production of metabolic reducing power within the cell. Hoxhaj
et al.
discovered that Akt directly phosphorylates nicotinamide adenine dinucleotide kinase (NADK). Catalytic activity of NADK is normally inhibited by its own amino-terminal domain, and phosphorylation by Akt relieved this inhibition. Active NADK produces nicotinamide adenine dinucleotide phosphate (NADP
+
). NADP
+
in turn is required to produce the reduced form of NADP
+
(NADPH), which is the primary cofactor for reductive metabolism in the cell.

Science
, this issue p.
1088
Structural basis for pH-dependent retrieval of ER proteins from the Golgi by the KDEL receptor
Authors: Bräuer Philipp , Parker Joanne L. , Gerondopoulos Andreas , Zimmermann Iwan , Seeger Markus A. , Barr Francis A. , Newstead Simon
Published: March 2019

Crystal structure of the KDEL receptor

Eukaryotic cells concentrate chaperones in the lumen of the endoplasmic reticulum (ER). These chaperones can be swept along the secretory pathway to the Golgi apparatus, from where they must be returned. For 20 years, cell biologists have known the identity of the KDEL (Lys-Asp-Glu-Leu) receptor responsible for this process, but the molecular basis for its function has remained elusive. Now, Bräuer
et al.
present crystal structures of the KDEL receptor, in both the apo ER state and KDEL retrieval signal–bound Golgi state. Comparisons of these two states identify the conformational switch that exposes the ER retrieval motif. The authors recapitulated the binding and release cycle of the receptor using purified components, confirming that the receptor is the minimal component required to bind KDEL ligands in the Golgi.

Science
, this issue p.
1103
Speaking freely on the internet
The Great Firewall of China: How to Build and Control an Alternative Version of the Internet
James Griffiths
Zed Books, 2019. 400 pp.
Authors: Martin Andrew
Published: March 2019

China's “great firewall” points toward a profound new mechanism of social control
EDTA-Modified Carbapenem Inactivation Method: a Phenotypic Method for Detecting Metallo-β-Lactamase-Producing
Enterobacteriaceae
Authors: Sfeir M. M. , Hayden J. A. , Fauntleroy K. A. , Mazur C. , Johnson J. K. , Simner P. J. , Das S. , Satlin M. J. , Jenkins S. G. , Westblade L. F.
Published: March 2019

The increase in the prevalence and impact of infections caused by carbapenemase-producing
Enterobacteriaceae
is a global health concern. Therefore, rapid and accurate methods to detect these organisms in any clinical microbiology laboratory, including those in resource-limited settings, are essential to prevent and contain their spread.
Evolution of the HIV-1 Rev Response Element during Natural Infection Reveals Nucleotide Changes That Correlate with Altered Structure and Increased Activity over Time
Authors: Sherpa Chringma , Jackson Patrick E. H. , Gray Laurie R. , Anastos Kathryn , Le Grice Stuart F. J. , Hammarskjold Marie-Louise , Rekosh David
Published: March 2019

HIV-1 replication requires interaction of the viral Rev protein with a
cis
-acting regulatory RNA, the Rev response element (RRE), whose sequence changes over time during infection within a single host. In this study, we show that the RRE is subject to selection pressure and that RREs from later time points in infection tend to have higher functional activity. Differences in RRE functional activity are attributable to specific changes in RNA structure. Our results suggest that RRE evolution during infection may be important for HIV pathogenesis and that efforts to develop therapies acting on this viral pathway should take this into account.
Recognition of Intracellular Bacteria by Inflammasomes
Authors: Broz Petr
Published: March 2019

Inflammasomes are multiprotein signaling complexes that are assembled by cytosolic sensors upon the detection of infectious or noxious stimuli. These complexes activate inflammatory caspases to induce host cell death and cytokine secretion and are an essential part of antimicrobial host defense. In this review, I discuss how intracellular bacteria are detected by inflammasomes, how the specific sensing mechanism of each inflammasome receptor restricts the ability of bacteria to evade immune recognition, and how host cell death is used to control bacterial replication
in vivo
.
Make It a Sweet Home: Responses of
Chlamydia trachomatis
to the Challenges of an Intravacuolar Lifestyle
Authors: Triboulet Sébastien , Subtil Agathe
Published: March 2019

Intravacuolar development has been adopted by several bacteria that grow inside a host cell. Remaining in a vacuole, as opposed to breaching the cytosol, protects the bacteria from some aspects of the cytosolic innate host defense and allows them to build an environment perfectly adapted to their needs. However, this raises new challenges: the host resources are separated from the bacteria by a lipid bilayer that is nonpermeable to most nutrients. In addition, the area of this lipid bilayer needs to expand to accommodate bacterial multiplication. This requires building material and energy that are not directly invested in bacterial growth. This article describes the strategies acquired by the obligate intracellular pathogen
Chlamydia trachomatis
to circumvent the difficulties raised by an intravacuolar lifestyle. We start with an overview of the origin and composition of the vacuolar membrane. Acquisition of host resources is largely, although not exclusively, mediated by interactions with membranous compartments of the eukaryotic cell, and we describe how the inclusion modifies the architecture of the cell and distribution of the neighboring compartments. The second part of this review describes the four mechanisms characterized so far by which the bacteria acquire resources from the host: (i) transport/diffusion across the vacuole membrane, (ii) fusion of this membrane with host compartments, (iii) direct transfer of lipids at membrane contact sites, and (iv) engulfment by the vacuole membrane of large cytoplasmic entities.
Enterococcal Genetics
Authors: Weaver Keith E.
Published: March 2019

The study of the genetics of enterococci has focused heavily on mobile genetic elements present in these organisms, the complex regulatory circuits used to control their mobility, and the antibiotic resistance genes they frequently carry. Recently, more focus has been placed on the regulation of genes involved in the virulence of the opportunistic pathogenic species
Enterococcus faecalis
and
Enterococcus faecium
. Little information is available concerning fundamental aspects of DNA replication, partition, and division; this article begins with a brief overview of what little is known about these issues, primarily by comparison with better-studied model organisms. A variety of transcriptional and posttranscriptional mechanisms of regulation of gene expression are then discussed, including a section on the genetics and regulation of vancomycin resistance in enterococci. The article then provides extensive coverage of the pheromone-responsive conjugation plasmids, including sections on regulation of the pheromone response, the conjugative apparatus, and replication and stable inheritance. The article then focuses on conjugative transposons, now referred to as integrated, conjugative elements, or ICEs, and concludes with several smaller sections covering emerging areas of interest concerning the enterococcal mobilome, including nonpheromone plasmids of particular interest, toxin-antitoxin systems, pathogenicity islands, bacteriophages, and genome defense.
Who will redislocate his/her shoulder? Predicting recurrent instability following a first traumatic anterior shoulder dislocation
Authors: Olds Margie K , Ellis Richard , Parmar Priya , Kersten Paula
Published: March 2019

Objective

To develop a multivariate tool that would predict recurrent instability after a first-time traumatic anterior shoulder dislocation.

Methods

Participants (aged 16–40 years) were recruited across New Zealand into a prospective cohort study. Baseline data were collected during a telephone interview and through examination of radiology records. Variables associated with recurrent instability were selected for the multivariate logistic regression model using backwards selection (p<0.10). Coefficients for those variables retained in the model were used to develop the predictive tool.

Results

Among the 128 participants, 36% had redislocated at least once in the first 12 months. Univariate analysis showed an increased likelihood of recurrent dislocation with bony Bankart lesions (OR=3.65, 95% CI 1.05 to 12.70, p=0.04) and participants who had: not been immobilised in a sling (OR = 0.38, 95% CI 0.15 to 0.98, p=0.05), higher levels of shoulder activity (OR=1.13, 95% CI 1.01 to 1.27, p=0.03), higher levels of pain and disability (OR=1.03, 95% CI 1.01 to 1.06, p=0.02), higher levels of fear of reinjury (OR=1.12, 95% CI 1.01 to 1.26, p=0.04) and decreased quality of life (OR=1.01, 95% CI 1.00 to 1.02, p=0.05). There was no significant difference in those with non-dominant compared with dominant shoulder dislocations (p=0.10) or in those aged 16–25 years compared with 26–40 years (p=0.07).

Conclusion

Six of seven physical and psychosocial factors can be used to predict recurrent shoulder instability following a first-time traumatic anterior shoulder dislocation.
Can green space quantity and quality help prevent postpartum weight gain? A longitudinal study
Authors: Feng Xiaoqi , Astell-Burt Thomas
Published: March 2019

Background

Postpartum weight gain is a well-known challenge for many mothers, but associations with green space quantity and quality have not been investigated.

Methods

This longitudinal study used data on 3843 mothers living in Australia tracked biennially for 15 years post partum from 2004 onwards. Multilevel growth curve models adjusted for confounding were used to examine the patterning of body mass index (BMI) in relation to green space quantity, measured by percentage land use, and green space quality, measured by self-report. Two-way interaction terms were fitted to investigate time-contingent associations between BMI and green space.

Results

Compared with mothers in areas with ≤5% green space, adjusted BMI coefficients were −0.43 kg/m2(SE 0.37), −0.69 kg/m2(SE 0.32) −0.86 kg/m2(SE 0.33) and −0.80 kg/m2(SE 0.41) among mothers in areas with 6%–10%, 11%–20%, 21%–40% and ≥41% green space, respectively. There were no independent associations between BMI and green space quality. Evidence suggested mothers living in areas with 21%–40% green space had the lowest BMI, whether they agreed that local parks were good quality (−0.89 kg/m2(SE 0.34)) or not (−0.93 kg/m2(SE 0.35)). Mothers in the greenest areas only had statistically significantly lower BMI if they perceived local parks as high quality (−0.89 kg/m2(SE 0.41)). There was limited evidence that these associations varied with respect to the number of years post partum.

Conclusion

These findings may suggest that urban greening strategies to achieve a threshold of at least 21% or more green space in an area may help reduce, but not fully prevent postpartum weight gain. Potential mechanisms warrant investigation.
Impact of obesity and physical inactivity on the long-term change in grip strength among middle-aged and older European adults
Authors: Wang Tianyu , Feng Wenjing , Li Suyun , Tan Qihua , Zhang Dongfeng , Wu Yili
Published: March 2019

Background

Grip strength is a well-established predictor of various chronic conditions and all-cause mortality. Body weight and physical activity (PA) are considered potential determinants of muscle strength. This study aimed to investigate gender-specific associations of baseline obesity and physical inactivity with long-term changes in grip strength among middle-aged and older European adults.

Methods

Data from the Survey of Health, Ageing and Retirement in Europe 2004–2015 which was conducted in 12 countries were analysed. Grip strength was repeatedly measured at five follow-up visits with average 2-year intervals. Obesity and physical inactivity at baseline were primary exposures. Generalised estimated equations stratified by gender were fitted.

Results

This study included 8616 males and 10 088 females with a median follow-up of 9.42 years. Significant interactions between obesity and time with grip strength were identified in both males (χ2interaction=16.65, p = 0.002) and females (χ2interaction=10.80, p = 0.029). No significant interaction between physical inactivity and time with grip strength was identified in males (χ2interaction=9.42, p = 0.051) or females (χ2interaction=5.62, p = 0.230). Those who were less physically active at baseline had weaker grip strength from the beginning at baseline (β = −2.753, p < 0.001 for males and β = −1.529, p < 0.001 for females) to Visit 6 (β = −2.794, p < 0.001 for males and β = −1.550, p < 0.001 for females). Further combined analysis suggested a trend that exposure to both obesity and physical inactivity was related to the fastest decline rate of grip strength.

Conclusions

This study provides the additional evidence that PA and obesity prevention earlier in life play an important role in maintaining grip strength during ageing.
Apoptosis induced by synthetic compounds containing a 3,4,5-trimethoxyphenyl fragment against lymphoid immature neoplasms
Authors: Santos-Pirath I.M. , Walter L.O. , Maioral M.F. , Neuenfeldt P.D. , Nunes R.J. , Santos-Silva M.C.
Published: March 2019

T-cell acute lymphoblastic leukemia is an aggressive hematological malignancy originating from the malignant transformation of progenitor T cells at different stages of development. The treatment causes severe adverse effects and is associated with relapses and high morbidity and mortality rates. The present study aimed to evaluate the cytotoxic activity of 28 new compounds containing 3,4,5-trimethoxyphenyl analogues on hematological neoplastic cells lines. Cytotoxicity screening by the MTT method revealed that compound 1d was the most promising. Cell viability of neoplastic cells decreased in a concentration- and time-dependent manner, with compound 1d not causing hemolysis or reducing peripheral blood mononuclear cells viability, suggesting a selective cytotoxicity. We also suggested that compound 1d induced apoptotic-like cell death with mitochondrial involvement in Jurkat cells.
Optimized material management in construction using multi-layer perceptron
Authors: Golkhoo Farzaneh , Moselhi Osama
Published: March 2019

Construction material represents a major component of the project cost. Therefore, it is essential to control material on construction job sites. Efficient material management system requires trade-offs and optimized balance among elements of material cost including purchase cost, storage cost, opportunity cost, ordering cost, and unavailability cost. Thus, there is a need to develop an automated method for optimizing the delivery and inventory of construction materials not only in the planning phase but also in the construction phase to account for introduced changes. In this research a novel genetic algorithm – multi-layer perceptron (GA-MLP) method is proposed to generate optimized material delivery schedule. Multi-layer perceptron (MLP) is utilized to improve genetic algorithm (GA) by generating memory to overcome local minima encountered in applying GA for optimization. This automated method supports contractors to buy construction materials with the least cost and without leading to material shortage or surplus. The proposed automated method has been validated through a numerical example. The obtained results demonstrate that GA-MLP outperform GA in optimizing construction material inventory.
Nonlinear dynamic analysis of a Stockbridge damper
Authors: Barbieri Nilson , Marchi Marlon Elias , Mannala Marcos José , Barbieri Renato , Barbieri Lucas de Sant’Anna Vitor , Barbieri Gabriel de Sant’Anna Vitor
Published: March 2019

The purpose of this work is to validate a nonlinear mathematical model (finite element method) for dynamic simulation of Stockbridge dampers of electric transmission line cables. To obtain the mathematical model, a nonlinear cantilever beam with a tip mass was used. The mathematical model incorporates a nonlinear stiffness matrix of the element due to the nonlinear curvature effect of the beam. To validate the mathematical model, the numerical results were compared with experimental data obtained on a machine adapted from cam test. Five different circular cam profiles with eccentricities of 0.25, 0.5, 0.75, 1.25, and 1.5 mm were used. Vibration data were collected through three accelerometers arranged along the sample. A good concordance was found between the numerical and experimental data. The same behavior was observed in tests of another Stockbridge damper excited by a shaker. The nonlinear behavior of the system was evidenced.
Generic algorithm to assess moisture susceptibility of simplified wall assemblies
Authors: Hagentoft Carl-Eric , Johansson Pär
Published: March 2019

A simplified wall assembly consisting of four material elements is considered. Optional vapor retarder and thermal resistances are located between the elements. A simplified numerical model is presented to perform probability-based risk analysis using the Monte Carlo method. The risk assessment of the wall assembly considers the interior and exterior climatic loads. The moisture transport mechanism accounted for in the analysis is diffusion. A prescribed rain load is assumed to be transferred directly to a chosen outer susceptible material element in the construction. A case study with a wooden wall structure is analyzed and the probability distribution of the time of wetness is presented for a case using 30 different climatic years, randomly varying indoor moisture excess, indoor temperature, and rain leakages. The results show that, in the case investigated in this paper, the simulations converged after 600 years. The proposed simplified model, combined with the use of Monte Carlo simulations, offers better opportunities for a systematic assessment of risk compared with the currently used simulation programs using only a design year.