bluuebunny/crossref_metadata_2025 huggingface dataset:
The efficiency and comparison of novel techniques for cell wall disruption in astaxanthin extraction from Haematococcus pluvialis
Authors: Liu Zhi‐Wei , Zeng Xin‐An , Cheng Jun‐Hu , Liu De‐Bao , Aadil Rana Muhammad
Published: May 2018

The efficiency of various techniques pulsed electric field (PEF), ultrasound (US), high‐pressure microfluidisation (HPMF), hydrochloric acid (HCl) and ionic liquids (ILs) for cell wall disruption in astaxanthin extraction from Haematococcus pluvialis was compared. The results indicated that ILs, HCl and HPMF treatment were shown the most efficient for cell disruption with more than 80% astaxanthin recovery. While the cell wall integrity of H. pluvialis cyst cell was less affected by US and PEF treatment. It was found that imidazolium‐based ILs showed the greater potential for cell disruption than pyridinium‐based and ammonium‐based ILs. Among all the ILs examined, 1‐butyl‐3‐methylimidazolium chloride ([Bmim] Cl) exhibited efficient cell disruption and capability of astaxanthin recovery at mild condition (pretreatment with 40% IL aqueous solution at 40 °C, followed by extraction with methanol at 50 °C) without extensive energy consumption and special facility requirement. In addition, recyclability of ILs was excellent.
Effect of surface charges on the polarization of BaTiO3 thin films investigated by UHV‐SPM
Authors: Suzuki Keigo , Hosokura Tadasu , Okamoto Takafumi , Steffes James , Murayama Koji , Tanaka Nobuhiko , Huey Bryan D.
Published: May 2018

Nanostructured BaTiO3 polar thin films are increasingly critical to the function of future multilayer ceramic capacitors and related oxide‐based electronic devices. The effect of surface charges on BaTiO3 polarization behavior is therefore investigated by ultra‐high vacuum scanning probe microscopy (UHV‐SPM) for 3 distinct morphologies—epitaxial, polycrystalline, and nanocrystalline films. Regardless of the film morphology, Kelvin probe force microscopy reveals that BaTiO3 thin film surfaces exhibit positive charging after contact scanning by various noble AFM probes due to the work function difference between tip and specimen. According to piezoresponse force microscopy, these positive charges uniformly stabilize downward polarized domains. However, the hysteresis and concomitant surface charging behavior are strongly sensitive to microstructure and defects. In particular, the stability and switching behavior are influenced by bulk and interfacial defect distributions and hence correlated to film deposition methods and grain size. Such morphology dependent properties for BaTiO3 films are revealed only through UHV measurements where screening charges from the ambient can be minimized, demonstrating the importance of UHV‐SPM for understanding ferroelectric thin films and nanostructures.
Microstructural, ferroelectric, and photoluminescent properties of (100)‐oriented Sm3+‐doped Na0.5Bi0.5TiO3 thin films
Authors: Huang Wenhua , Du Xingru , Ismail Muhammad , Hao Aize , Wu Jiang , He Shuai , Qin Ni , Bao Dinghua
Published: May 2018

(100)C‐oriented Na0.5Bi0.5‐xSmxTiO3 (NBST) lead‐free ferroelectric thin films were prepared on Pt/Ti/SiO2/Si substrates by chemical solution deposition method, and their microstructural, dielectric, ferroelectric, and photoluminescent properties were studied. X‐ray diffraction and scanning electron microscopy analysis indicated that both the grain size and (100)C orientation degree of NBST thin films were decreased by doping Sm3+ ions. Raman spectra showed that structural symmetry of NBST thin films decreased at low Sm3+ doping concentration and then increased at high doping concentration of Sm3+ ions. An appropriate amount of Sm3+ dopants was confirmed to enhance dielectric and ferroelectric properties of the NBST thin films. Among all the compositions, the Na0.5Bi0.492Sm0.008TiO3 thin film exhibited the largest remnant polarization (2Pr) of 27.3 μC/cm2 and high dielectric constant of 1068, as well as a low dielectric loss of 0.04. Temperature‐ and frequency‐dependent dielectric characteristics illustrated the relaxor ferroelectric behavior of Na0.5Bi0.492Sm0.008TiO3 thin film. Meanwhile, the Na0.5Bi0.492Sm0.008TiO3 thin film also showed optimal orange‐red emission at 600 nm, which is originating from the 4G5/2 → 4H7/2 transition of Sm3+ ions.
Postprocedural LGE‐CMR comparison of laser and radiofrequency ablation lesions after pulmonary vein isolation
Authors: Figueras i Ventura Rosa M. , Mǎrgulescu Andrei D. , Benito Eva M. , Alarcón Francisco , Enomoto Norihiro , Prat‐Gonzalez Susanna , Perea Rosario J. , Borràs Roger , Chipa Fredy , Arbelo Elena , Tolosana Jose M. , Brugada Josep , Berruezo Antonio , Mont Lluis
Published: May 2018

Introduction

The purpose of this study was to compare the anatomical characteristics of scar formation achieved by visual‐guided laser balloon (Laser) and radiofrequency (RF) pulmonary vein isolation (PVI), using late‐gadolinium‐enhanced cardiac magnetic resonance imaging (LGE‐CMR).

Methods and results

We included 17 patients with paroxysmal or early persistent drug resistant AF who underwent Laser ablation; 2 were excluded due to procedure‐related complications. The sample was matched with a historical group of 15 patients who underwent PVI using RF. LGE‐CMR sequences were acquired before and 3 months post‐PVI. Ablation gaps were defined as pulmonary vein (PV) perimeter sections showing no gadolinium enhancement. The number of ablation gaps was lower in Laser versus RF ablations (median 7 vs. 14, P  =  0.015). Complete anatomical PVI (circumferential scar around PV, without gaps) was more frequently achieved with Laser than with RF (39% vs. 19% of PVs, P  =  0.025). Fewer gaps were present at the superior and anterior left PV and posterior right PV antral regions in the Laser group, compared to RF. Scar extension into the PVs was similar in both groups, although RF produced more extensive ablation scar toward the LA body. AF recurrences at 1 year were similar in both groups (Laser 36% vs. RF 27%, P  =  1.00).

Conclusions

Compared to RF, Laser ablation achieved more complete anatomical PVI, with less LA scar extension. However, AF recurrence appears to be similar after Laser compared to RF ablation. Further studies are needed to assess whether the anatomical advantages of Laser ablation translate into clinical benefit in patients with AF.
The SHH/Gli axis regulates CD90‐mediated liver cancer stem cell function by activating the IL6/JAK2 pathway
Authors: Zhang Ketao , Che Siyao , Pan Chuzhi , Su Zheng , Zheng Shangyou , Yang Shanglin , Zhang Huayao , Li Wenda , Wang Weidong , Liu Jianping
Published: May 2018

The cell surface antigen CD90 has recently been established as a promising marker for liver cancer stem cells. This study aimed to investigate potential implications of SHH/Gli signalling in CD90+ liver cancer stem cells. Correlation of the expression of SHH signalling components and CD90 in liver cancer cells and clinical tissues, as well as in enriched CD90+ liver cancer stem cells and the TCGA database, were analysed by quantitative RT‐PCR, Western blotting and flow cytometry. Functional analysis was conducted by siRNA‐mediated CD90, Gli1 and Gli3 gene knockdown, SHH treatment and application of the JAK2 inhibitor AZD1480 and IL6 neutralizing antibody in CD90+ liver cancer stem cells, followed by cell proliferation, migration, sphere formation and tumorigenicity assays. CD90 expression exhibited a high positive correlation with Gli1 and Gli3 in multiple liver cancer cell lines and human cancerous liver tissues, both of which showed a significant increase in liver cancer. Analysis of TCGA data revealed an association of CD90, Gli1 and Gli3 with a short overall survival and positive correlation between CD90 expression and Gli3 expression level. The stem cell potentials of CD90+ 97L liver cancer cells were greatly impaired by Gli1/3 knockdown with siRNA but enhanced by SHH treatment. Application of the JAK2 inhibitor AZD1480 and IL6 neutralizing antibody showed the CD90 and SHH/Gli‐regulated liver cancer stem cell functions were mediated by the IL6/JAK2/STAT3 pathway. The stem cell properties of CD90+ liver cancer cells are regulated by the downstream SHH/Gli and IL6/JAK2/STAT3 signalling pathways.
Public Child‐Care Expansion and Changing Gender Ideologies of Parents in Germany
Authors: Zoch Gundula , Schober Pia S.
Published: May 2018

This study investigates whether the expansion of public child care for children aged younger than 3 years in Germany has been associated with individual‐level change in gender ideologies. The authors develop and test a theoretical framework of the short‐term impact of family policy institutions on ideology change. The analysis links the German Family Panel pairfam (2008 to 2015) with administrative records on county‐level child‐care provision for those aged younger than 3 years and applies fixed effects panel models. The findings show that the child‐care expansion has been associated with moderate changes toward less‐traditional gender ideologies only among mothers in West Germany and mostly among mothers without a college degree. In East Germany, the authors found evidence of more traditional gender ideologies among mothers without a college degree as the child‐care reform unfolded. The results provide evidence that policy reforms may alter gender ideologies also in the short‐term.
Fast reactivation of photosynthesis in arctic phytoplankton during the polar night1
Authors: Kvernvik Ane Cecilie , Hoppe Clara Jule Marie , Lawrenz Evelyn , Prášil Ondřej , Greenacre Michael , Wiktor Józef Maria , Leu Eva
Published: May 2018

Arctic microalgae experience long periods of continuous darkness during the polar night, when they are unable to photosynthesize. Despite numerous studies on overwintering strategies, such as utilization of stored energy products, formation of resting stages, reduction of metabolic rates and heterotrophic lifestyles, there have been few attempts to assess the in situ physiological state and restoration of the photosynthetic apparatus upon re‐illumination. In this study, we found diverse and active marine phytoplankton communities during the polar night at 78°N. Furthermore, we observed rapid changes (≤20 min) in the efficiency of photosynthetic electron transport upon re‐illumination. High photosynthetic capacity and net primary production were established after 24 h of re‐illumination. Our results suggest that some Arctic autotrophs maintain fully functional photosystem II and downstream electron acceptors during the polar night even though the low in situ net primary production levels measured in January prove that light was not sufficient to support any measurable primary production. Due to low temperatures resulting in low respiratory rates as well as the absence of photodamage during the polar night, maintenance of basic photosynthetic machinery may actually pose relatively low metabolic costs for algal cells. This could allow Arctic microalgae to endure the polar night without the formation of dormant stages, enabling them to recover and take advantage of light immediately upon the suns return during the winter–spring transition.
PrgB promotes aggregation, biofilm formation, and conjugation through DNA binding and compaction
Authors: Schmitt Andreas , Jiang Kai , Camacho Martha I. , Jonna Venkateswara Rao , Hofer Anders , Westerlund Fredrik , Christie Peter J , Berntsson Ronnie P‐A
Published: May 2018

Gram‐positive bacteria deploy type IV secretion systems (T4SSs) to facilitate horizontal gene transfer. The T4SSs of Gram‐positive bacteria rely on surface adhesins as opposed to conjugative pili to facilitate mating. Enterococcus faecalis PrgB is a surface adhesin that promotes mating pair formation and robust biofilm development in an extracellular DNA (eDNA) dependent manner. Here, we report the structure of the adhesin domain of PrgB. The adhesin domain binds and compacts DNA in vitro. In vivo PrgB deleted of its adhesin domain does not support cellular aggregation, biofilm development and conjugative DNA transfer. PrgB also binds lipoteichoic acid (LTA), which competes with DNA binding. We propose that PrgB binding and compaction of eDNA facilitates cell aggregation and plays an important role in establishment of early biofilms in mono‐ or polyspecies settings. Within these biofilms, PrgB mediates formation and stabilization of direct cell‐cell contacts through alternative binding of cell‐bound LTA, which in turn promotes establishment of productive mating junctions and efficient intra‐ or inter‐species T4SS‐mediated gene transfer.
Image velocimetry and spectral analysis enable quantitative characterization of larval zebrafish gut motility
Authors: Ganz J. , Baker R. P. , Hamilton M. K. , Melancon E. , Diba P. , Eisen J. S. , Parthasarathy R.
Published: May 2018

Background

Normal gut function requires rhythmic and coordinated movements that are affected by developmental processes, physical and chemical stimuli, and many debilitating diseases. The imaging and characterization of gut motility, especially regarding periodic, propagative contractions driving material transport, are therefore critical goals. Previous image analysis approaches have successfully extracted properties related to the temporal frequency of motility modes, but robust measures of contraction magnitude, especially from in vivo image data, remain challenging to obtain.

Methods

We developed a new image analysis method based on image velocimetry and spectral analysis that reveals temporal characteristics such as frequency and wave propagation speed, while also providing quantitative measures of the amplitude of gut motion.

Key Results

We validate this approach using several challenges to larval zebrafish, imaged with differential interference contrast microscopy. Both acetylcholine exposure and feeding increase frequency and amplitude of motility. Larvae lacking enteric nervous system gut innervation show the same average motility frequency, but reduced and less variable amplitude compared to wild types.

Conclusions & Inferences

Our image analysis approach enables insights into gut dynamics in a wide variety of developmental and physiological contexts and can also be extended to analyze other types of cell movements.
Identification of natural variants affecting chlorophyll content dynamics during rice seedling development
Authors: Lin Po‐Chun , Tsai Yu‐Chang , Hsu Sheng‐Kai , Ou Jen‐Hsiang , Liao Chen‐Tuo , Tung Chih‐Wei
Published: May 2018

Seedling vigour is an important characteristic in relation to crop growth and yield. Traits such as photosynthetic capacity and chlorophyll content contribute significantly to seedling establishment at the early growth stage in various crop species, including rice. A diverse panel of 227 rice varieties from several countries was evaluated to determine chlorophyll contents at multiple time points during the seedling stage using a soil–plant analysis development (SPAD) meter, a non‐destructive portable device. Using new statistical approaches, several chromosomal regions associated with variations in chlorophyll content in the third leaf at 13, 16 and 19 days after imbibition were detected. A single nucleotide polymorphism (SNP) cluster on the end of chromosome 11 was significantly associated with the onset of leaf senescence. This region was enriched with genes related to cell death and the stress response. We have identified rice germplasm showing delayed‐senescence phenotypes, these could be suitable donors and genetic resources for breeding, and the use of significant SNP markers associated with these traits could enhance the efficiency of their selection in breeding programmes.
Patient‐to‐patient peer mentor support in dialysis: Improving the patient experience
Authors: Bennett Paul N. , St. Clair Russell Jennifer , Atwal Jug , Brown Lashone , Schiller Brigitte
Published: May 2018

Greater focus on patient‐reported outcome measures for dialysis patients and an increased patient engagement focus has highlighted a lack of formal patient‐generated strategies. Patient‐to‐patient peer mentoring is one approach that may improve the outcomes for people receiving dialysis. This review aims to synthesize quantitative and qualitative studies investigating dialysis‐associated patient‐to‐patient peer mentor support among adults with chronic kidney disease and end stage kidney disease. Research studies describe the benefits of peer mentor programs in dialysis to include: improved goal setting, decision‐making and increased self‐management. While a variety of program formats exist, a combination of face‐to‐face and telephone peer support models are recommended and formal training of mentors is required. In addition, the formal support of dialysis clinicians, nephrologists and administrators is vital for the success of a dialysis patient‐to‐patient peer mentor program.
Handgrip and knee extension strength as predictors of cancer mortality: A systematic review and meta‐analysis
Authors: García‐Hermoso A. , Ramírez‐Vélez R. , Peterson M. D. , Lobelo F. , Cavero‐Redondo I. , Correa‐Bautista J. E. , Martínez‐Vizcaíno V.
Published: May 2018

The specific role of different strength measures on mortality risk needs to be clarified to gain a better understanding of the clinical importance of different muscle groups, as well as to inform intervention protocols in relation to reducing early mortality. The aim of the systematic review and meta‐analysis was to determine the relationship between muscular strength and risk of cancer mortality. Eligible cohort studies were those that examined the association between muscular strength, as assessed using validated tests, and cancer mortality in healthy youth and adults. The hazard ratio (HR) estimates obtained were pooled using random effects meta‐analysis models. The outcome was cancer mortality assessed using the HR (Cox proportional hazards model). Eleven prospective studies with 1 309 413 participants were included, and 9787 cancer‐specific deaths were reported. Overall, greater handgrip (HR = 0.97, 95% CI, 0.92‐1.02; P = .055; I2 = 18.9%) and knee extension strength (HR = 0.98, 95% CI, 0.95‐1.00; P = .051; I2 = 60.6%) were barely significant associated with reduced risk of cancer mortality. Our study suggests that higher level of muscular strength is not statistically associated with lower risk of cancer mortality.
Inventing critical development: A Brazilian geographer and his Northern networks
Authors: Ferretti Federico , Viotto Pedrosa Breno
Published: May 2018

This paper addresses a corpus of unpublished sources in a first attempt to reconstruct the exile networks of Brazilian geographer Milton Santos, placing his geographical and political work in the context of present‐day debates on development, anti‐development and critical development. Our main argument is twofold: first, we argue that Santos played important although poorly understood roles in the debates that shaped both Anglophone and French‐speaking critical geographers in the 1960s and 1970s. Far from being passive receivers of ideas from the Global North, Southern scholars like Santos contributed to shape worldwide concepts in critical studies on development and underdevelopment. Second, the ideas spiralling out of Santos’ networks can still nourish present‐day scholars in development and critical development theories who are willing to criticise the “ideology of development” without forgetting the material existence of poverty and socio‐spatial marginalisation. Finally, Santos’ biography and networks provide an example of cosmopolitan and multilingual intellectual work that can provide insights for the present‐day internationalisation of critical and radical geographies.
Bevel depth profiling by high-spatial-resolution sputtered neutral mass spectrometry with laser postionization
Authors: Kashiwagi Takahiro , Nagashima Satoru , Ishikawa Takeharu , Takano Akio , Liu Suet-Yi , Takenaka Hisataka , Endo Katsumi , Fujii Masaaki
Published: May 2018

Secondary-ion mass spectrometry (SIMS) sputter depth profiling is used for the quantitative depth profile analysis of impurities. However, SIMS suffers from a large quantitative uncertainty and depth-scale uncertainty at the interfaces of heteromultilayers and in the near-surface region, because the secondary ion yield and sputtering yield are significantly influenced by matrix effects and accumulation effects of the primary ion. In this paper, the authors report on the development of a new depth profiling method with good depth-scale accuracy and low matrix effects to overcome these problems. This was achieved through the combination of high-spatial-resolution bevel depth profiling and sputtered neutral mass spectrometry with laser postionization (laser-SNMS). The sample used to evaluate this new bevel depth profiling method was a silicon on insulator wafer obtained using the separation by implantation of oxygen technique and implanted with boron. Depth profiles were obtained using both SIMS and laser-SNMS and evaluated by comparison with the stopping and range of ions in matter (SRIM) simulation. Although both methods afforded quite good depth resolutions, in SIMS the secondary ion signal intensity for boron was amplified by the influence of the matrix effect and showed a discontinuous profile shape at the interfaces, whereas the profile for boron obtained using laser-SNMS was consistent with the SRIM results and exhibited high continuity. By using a combination of the bevel depth profiling method and laser-SNMS method, it was confirmed that an easy-to-analyze depth profile could be obtained for the dopant concentration in multilayer samples, which is difficult to obtain using the conventional SIMS method.
Tip-enhanced Raman scattering of DNA aptamers for Listeria monocytogenes
Authors: He Siyu , Li Hongyuan , Gomes Carmen L. , Voronine Dmitri V.
Published: May 2018

Optical detection and conformational mapping of aptamers are important for improving medical and biosensing technologies and for better understanding of biological processes at the molecular level. The authors investigate the vibrational signals of deoxyribonucleic acid aptamers specific to Listeria monocytogenes immobilized on gold substrates using tip-enhanced Raman scattering (TERS) spectroscopy and nanoscale imaging. The authors compare topographic and nano-optical signals and investigate the fluctuations of the position-dependent TERS spectra. They perform spatial TERS mapping with 3 nm step size and discuss the limitation of the resulting spatial resolution under the ambient conditions. TERS mapping provides information about the chemical composition and conformation of aptamers and paves the way to future label-free biosensing.
Transitioning Out of Professional Sport: The Psychosocial Impact of Career-Ending Non-Musculoskeletal Injuries Among Male Cricketers From England and Wales
Authors: Arvinen-Barrow Monna , DeGrave Kelsey , Pack Stephen , Hemmings Brian
Published: May 2018

The purpose of this study was to document the lived experiences of professional cricketers who had encountered a career-ending non-musculoskeletal injury. Three male cricketers each with over nine years of playing experience in professional cricket representing England and Wales participated in retrospective in-depth semi-structured interviews. The Interpretative Phenomenological Analysis revealed that at the time of the injury, the participants were at the “final stretch” of their professional sporting careers and that despite a range of unpleasant reactions to injury, all participants experienced a healthy career transition out of sport. To best prepare athletes for a life outside of sport, ensuring athletes have sufficient plans in motion early on in their careers can reduce external and internal stressors, which if not addressed, can increase sport injury risk and have a negative effect on athletes’ reactions post-injury.
The Multifaceted Meaning of Sport Psychology Professional Quality of Life
Authors: Quartiroli Alessandro , Etzel Edward F. , Knight Sharon M. , Zakrajsek Rebecca A.
Published: May 2018

Experienced and senior sport psychology practitioners achieved longevity in effective professional practice by embracing sustainable approaches to their profession, assumed to be influenced by their positive professional quality of life. The aim of this study was to gain insight into how these practitioners defined and attended to their profession-specific quality of life. Utilizing Consensual Qualitative Research method, researchers examined the perceptions and meanings that 20 internationally located practitioners attributed to their Sport Psychology-Professional Quality of Life (SP-PQL). Findings revealed a view of SP-PQL that encompassed five domains: (a) the lived experience of SP-PQL, (b) the nature of the SP profession, (c) SP-PQL as an ongoing journey, (d) deliberate engagement in the SP profession, and (e) the interconnection between the personal and the professional. These practitioners recognized the importance of a positive SP-PQL as a foundation for a positive, effective, and long-lasting career in the field.
Gut microbiota utilize immunoglobulin A for mucosal colonization
Authors: Donaldson G. P. , Ladinsky M. S. , Yu K. B. , Sanders J. G. , Yoo B. B. , Chou W.-C. , Conner M. E. , Earl A. M. , Knight R. , Bjorkman P. J. , Mazmanian S. K.
Published: May 2018

Benign colonization of the gut

Microbial communities in the gut can be highly individual. What engenders this specificity? The gut characteristically produces gram quantities of immunoglobulin A (IgA) antibody, which is presumed to protect the gut from pathogen attack. Donaldson
et al.
engineered strains of
Bacteroides fragilis
, a common human commensal, to modify its surface capsule, which affects its ability to colonize the germ-free mouse gut. Capsule changes altered the capacity of IgA to bind to the different mutants. It seems that this commensal species exploits IgA sticking power specifically to give it a competitive edge and to promote its establishment in the gut.

Science
, this issue p.
795
Activation mechanism of a human SK-calmodulin channel complex elucidated by cryo-EM structures
Authors: Lee Chia-Hsueh , MacKinnon Roderick
Published: May 2018

How calcium gates a potassium channel

Small-conductance Ca
2+
-activated K
+
(SK) channels are expressed throughout the nervous system and affect both the intrinsic excitability of neurons and synaptic transmission. An increase in the concentration of intracellular calcium opens the channels to conduct potassium across the cell membrane. Lee and MacKinnon report cryo–electron microscopy structures of human SK4-calmodulin channel complexes. Activation occurs when calcium binds to calmodulin, a protein with two lobes, known as C and N, separated by a flexible region. Each monomer in the channel tetramer binds constitutively to the C-lobe of calmodulin. The N-lobe of calmodulin is reasonably unconstrained until it binds calcium. With calcium bound, it then binds to the channel and induces conformational changes that open the pore.

Science
, this issue p.
508
Louise M. Slaughter (1929–2018)
Authors: Haseltine Florence
Published: May 2018

Trailblazing congresswoman and women's rights advocate
Global data meet EU rules
Authors: Glinos Kostas
Published: May 2018

We are at the beginning of the “fourth industrial revolution,” with unprecedented capabilities to acquire, process, and communicate data. As with all revolutions, it holds great promise as well as dangers. Outrage at large-scale privacy breaches demonstrates the perils of taking protection of personal data lightly and reminds us that technological progress challenges policies, values, and approaches to ethics. The European Union (EU) General Data Protection Regulation (GDPR) that takes effect on 25 May offers never-before-seen protections and control by individuals of their personal data, including many provisions for research. Although this should increase public trust and therefore propensity to share data, many implementation details and safeguards have yet to be established. It is clear, however, that interoperability of policies will be essential to promote data sharing across research communities within the EU and globally.
Self-Resistance during Muraymycin Biosynthesis: a Complementary Nucleotidyltransferase and Phosphotransferase with Identical Modification Sites and Distinct Temporal Order
Authors: Cui Zheng , Wang Xia-Chang , Liu Xiaodong , Lemke Anke , Koppermann Stefan , Ducho Christian , Rohr Jürgen , Thorson Jon S. , Van Lanen Steven G.
Published: May 2018

Muraymycins are antibacterial natural products from
Streptomyces
spp. that inhibit translocase I (MraY), which is involved in cell wall biosynthesis. Structurally, muraymycins consist of a 5′-
C
-glycyluridine (GlyU) appended to a 5″-amino-5″-deoxyribose (ADR), forming a disaccharide core that is found in several peptidyl nucleoside inhibitors of MraY. For muraymycins, the GlyU-ADR disaccharide is further modified with an aminopropyl-linked peptide to generate the simplest structures, annotated as the muraymycin D series. Two enzymes encoded in the muraymycin biosynthetic gene cluster, Mur29 and Mur28, were functionally assigned
in vitro
as a Mg·ATP-dependent nucleotidyltransferase and a Mg·ATP-dependent phosphotransferase, respectively, both modifying the 3″-OH of the disaccharide. Biochemical characterization revealed that both enzymes can utilize several nucleotide donors as cosubstrates and the acceptor substrate muraymycin also behaves as an inhibitor. Single-substrate kinetic analyses revealed that Mur28 preferentially phosphorylates a synthetic GlyU-ADR disaccharide, a hypothetical biosynthetic precursor of muraymycins, while Mur29 preferentially adenylates the D series of muraymycins. The adenylated or phosphorylated products have significantly reduced (170-fold and 51-fold, respectively) MraY inhibitory activities and reduced antibacterial activities, compared with the respective unmodified muraymycins. The results are consistent with Mur29-catalyzed adenylation and Mur28-catalyzed phosphorylation serving as complementary self-resistance mechanisms, with a distinct temporal order during muraymycin biosynthesis.
Evaluation of the Use of Rectal Swabs for Laboratory Diagnosis of Clostridium difficile Infection
Authors: Jazmati N. , Kirpal E. , Piepenbrock E. , Stelzer Y. , Vehreschild M. J. G. T. , Seifert H.
Published: May 2018

For the diagnosis of
Clostridium difficile
infection (CDI), microbiological testing is almost always accomplished through the analysis of stool specimens. We evaluated the performances of rectal swabs with liquid transport medium (FS) and nylon flocked dry swabs for the detection of
C. difficile
. Additionally, the impact on the diagnostic yield of storing swabs at −80°C for up to 3 months was evaluated. Sixty clinical stool samples positive for
C. difficile
by PCR were used for simulating rectal swabbing. FS and dry swabs were dipped into the stool and tested by PCR directly after swabbing at 1 and 3 months after storage at −80°C. Stool and the liquid medium of FS were additionally tested by a combination of glutamate dehydrogenase antigen (GDH) testing and toxin A/B enzyme immunoassay (EIA), as well as by toxigenic culture (TC). Using dry swabs, the PCR-based detection rate of
C. difficile
was equal to the rate using stool samples (30/30 [100%]), whereas the detection rate in FS was significantly lower (25/30 [83.2%];
P
= 0.019). The sensitivities of FS for detecting
C. difficile
by PCR, TC, GDH testing, and toxin A/B EIA were 83.3%, 85.7%, 88%, and 68.9%, respectively. Storage of swabs at −80°C had no impact on the detection rate. FS cannot replace stool samples in the two-step laboratory diagnosis of CDI, as the sensitivities were too low, probably due to diluting effects of the fecal sample in the liquid medium. For simple PCR-based detection of
C. difficile
, dry swabs proved to be a suitable alternative to the use of stool samples.
Use of verbal autopsy and social autopsy in humanitarian crises
Authors: Thomas Lisa-Marie , D’Ambruoso Lucia , Balabanova Dina
Published: May 2018

Introduction

Two billion people live in countries affected by conflict, violence and fragility. These are exceptional situations in which mortality shifts dramatically and in which civil registration and vital statistics systems are often weakened or cease to function. Verbal autopsy and social autopsy (VA and SA) are methods used to assign causes of death and understand the contexts in which these occur, in settings where information is otherwise unavailable. This review sought to explore the use of VA and SA in humanitarian crises, with a focus on how these approaches are used to inform policy and programme responses.

Methods

A rapid scoping review was conducted on the use of VA and SA in humanitarian crises in low and middle-income countries since 1991. Drawing on a maximum variation approach, two settings of application (‘application contexts’) were selected and investigated via nine semi-structured expert interviews.

Results

VA can determine causes of death in crisis-affected populations where no other registration system is in place. Combined with SA and active community involvement, these methods can deliver a holistic view of obstacles to seeking and receiving essential healthcare, yielding context-specific information to inform appropriate responses. The contexts in which VA and SA are used require adaptations to standard tools, and new mobile developments in VA raise specific ethical considerations. Furthermore, collecting and sythesising data in a timely, continuous manner, and ensuring coordination and communication between agencies, is important to realise the potential of these approaches.

Conclusion

VA and SA are valuable research methods to foster evidence-informed responses for populations affected by humanitarian crises. When coordinated and communicated effectively, data generated through these methods can help to identify levels, causes and circumstances of deaths among vulnerable groups, and can enable planning and allocating resources effectively, potentially improving health system resilience to future crises.
Evaluating the impact of a maternal health voucher programme on service use before and after the introduction of free maternity services in Kenya: a quasi-experimental study
Authors: Dennis Mardieh L , Abuya Timothy , Campbell Oona Maeve Renee , Benova Lenka , Baschieri Angela , Quartagno Matteo , Bellows Benjamin
Published: May 2018

Introduction

From 2006 to 2016, the Government of Kenya implemented a reproductive health voucher programme in select counties, providing poor women subsidised access to public and private sector care. In June 2013, the government introduced a policy calling for free maternity services to be provided in all public facilities. The concurrent implementation of these interventions presents an opportunity to provide new insights into how users adapt to a changing health financing and service provision landscape.

Methods

We used data from three cross-sectional surveys to assess changes over time in use of 4+ antenatal care visits, facility delivery, postnatal care and maternal healthcare across the continuum among a sample of predominantly poor women in six counties. We conducted a difference-in-differences analysis to estimate the impact of the voucher programme on these outcomes, and whether programme impact changed after free maternity services were introduced.

Results

Between the preintervention/roll-out phase and full implementation, the voucher programme was associated with a 5.5% greater absolute increase in use of facility delivery and substantial increases in use of the private sector for all services. After free maternity services were introduced, the voucher programme was associated with a 5.7% higher absolute increase in use of the recommended package of maternal health services; however, disparities in access to facility births between voucher and comparison counties declined. Increased use of private sector services by women in voucher counties accounts for their greater access to care across the continuum.

Conclusions

Our findings show that the voucher programme is associated with a modest increase in women’s use of the full continuum of maternal health services at the recommended timings after free maternity services were introduced. The greater use of private sector services in voucher counties also suggests that there is need to expand women’s access to acceptable and affordable providers.
Chronic Stress protection for postnatal dEpREssioN prEvention (SERENE): a protocol for an exploratory study
Authors: Tharwat Dahlia , Trousselard Marion , Balès Mélanie , Sutter-Dallay Anne-Laure , Fromage Dominique , Spitz Elisabeth , Dallay Dominique , Harvey Thierry , Welter Eric , Coatleven Frédéric , Cherier Lydie , Teissèdre Frédérique , Pouly Jean-Luc , Dutheil Frédéric , Duffaud Anaïs M
Published: May 2018

Introduction

The prevalence of postnatal depression (PND) is significant: reaching up to 20% in the general population. In mechanistic terms, the risk of PND lies in an interaction between a maternal psychophysiological vulnerability and a chronic environmental context of stress. On the one hand, repetition of stressor during pregnancy mimics a chronic stress model that is relevant to the study of the allostatic load and the adaptive mechanisms. On the other hand, vulnerability factors reflect a psychological profile mirroring mindfulness functioning (psychological quality that involves bringing one’s complete and non-judgemental attention to the present experience on a moment-to-moment basis). This psychological resource is linked to protective and resilient psychic functioning. Thus, PND appears to be a relevant model for studying the mechanisms of chronic stress and vulnerability to psychopathologies.

In this article, we present the protocol of an ongoing study (started in May 2017).

Methods and analysis

The study is being carried out in five maternities and will involve 260 women. We aim to determine the predictive psychobiological factors for PND emergence and to provide a better insight into the mechanisms involved in chronic stress during pregnancy. We use a multidisciplinary approach that encompasses psychological resources and biophysiological and genetic profiles in order to detect relevant vulnerability biomarkers for chronic stress and the development of PND. To do so, each woman will be involved in the study from her first trimester of pregnancy until 12 months postdelivery.

Ethics and dissemination

Ethics approval was obtained from the Ile de France III Ethics Committee, France (2016-A00887-44). We aim to disseminate the findings through international conferences and international peer-reviewed journals.

Trial registrationnumber

NCT03088319; Pre-results.
Identifying Children with HEreditary Coagulation disorders (iCHEC): a protocol for a prospective cohort study
Authors: Stokhuijzen Eva , Rand Margaret L , Cnossen Marjon H , Biss Tina T , James Paula D , Suijker Monique H , Peters Marjolein , van der Lee Johanna H , Peters Bram , Meijer Alexander B , Blanchette Victor S , Fijnvandraat Karin
Published: May 2018

Introduction

It is challenging to obtain a reliable bleeding history in children who are referred for a suspected inherited bleeding disorder. Bleeding symptoms may be subtle as children face fewer haemostatic challenges compared with adults. In order to standardise bleeding histories, questionnaires have been developed, called bleeding assessment tools (BATs). Although it has been shown that high bleeding scores are associated with the presence of a mucocutaneous bleeding disorder, these BATs lack sensitivity, efficiency and flexibility in the paediatric setting. We developed a new BAT (the iCHEC (identifying Children with HEreditary Coagulation disorders) BAT) to improve on these characteristics. We aim to evaluate the diagnostic accuracy of the iCHEC BAT as a screening tool for children who are suspected for having a bleeding disorder.

Methods and analysis

This is a prospective cohort study. Children (age 0–18 years) suspected for a bleeding disorder who present at tertiary haematology clinics, and/or their parents/guardians, will be asked to complete the iCHEC BAT. Sensitivity was increased by inclusion of paediatric-specific bleeding symptoms and novel qualitative questions per bleeding symptom. Efficiency was improved by developing a self-administered (online) version of the questionnaire. Flexibility for changes in the bleeding phenotype of developing children was improved by including questions that define when the bleeding symptoms occurred in the past. The diagnostic accuracy of the specific bleeding items will be evaluated by receiver operator characteristic curves, using classification based on the results from laboratory assessment as the reference standard. Analysis of the discriminative power of individual bleeding symptoms will be assessed.

Ethics and dissemination

The study has been approved by the medical ethics committees of all participating centres in the Netherlands, Canada and the UK. All paediatric subjects and/or their parents/guardians will provide written informed consent. Study results will be submitted for publication in peer-reviewed journals.
Measuring outcome differences associated with STEMI screening and diagnostic performance: a multicentred retrospective cohort study protocol
Authors: Yiadom Maame Yaa A B , Mumma Bryn E , Baugh Christopher W , Patterson Brian W , Mills Angela M , Salazar Gilberto , Tanski Mary , Jenkins Cathy A , Vogus Timothy J , Miller Karen F , Jackson Brittney E , Lehmann Christoph U , Dorner Stephen C , West Jennifer L , Wang Thomas J , Collins Sean P , Dittus Robert S , Bernard Gordon R , Storrow Alan B , Liu Dandan
Published: May 2018

Introduction

Advances in ST-segment elevation myocardial infarction (STEMI) management have involved improving the clinical processes connecting patients with timely emergency cardiovascular care. Screening upon emergency department (ED) arrival for an early ECG to diagnose STEMI, however, is not optimal for all patients. In addition, the degree to which timely screening and diagnosis are associated with improved time to intervention and postpercutaneous coronary intervention outcomes, under more contemporary practice conditions, is not known.

Methods

We present the methods for a retrospective multicentre cohort study anticipated to include 1220 patients across seven EDs to (1) evaluate the relationship between timely screening and diagnosis with treatment and postintervention clinical outcomes; (2) introduce novel measures for cross-facility performance comparisons of screening and diagnostic care team performance including: door-to-screening, door-to-diagnosis and door-to-catheterisation laboratory arrival times and (3) describe the use of electronic health record data in tandem with an existing disease registry.

Ethics and dissemination

The completion of this study will provide critical feedback on the quality of screening and diagnostic performance within the contemporary STEMI care pathway that can be used to (1) improve emergency care delivery for patients with STEMI presenting to the ED, (2) present novel metrics for the comparison of screening and diagnostic care and (3) inform the development of screening and diagnostic support tools that could be translated to other care environments. We will disseminate our results via publication and quality performance data sharing with each site. Institutional ethics review approval was received prior to study initiation.
Managing headshaking in horses: an update
Authors: Roberts Veronica
Published: May 2018

It is not uncommon for equine vets to be asked to examine a horse which is exhibiting headshaking. This article covers my approach to reaching a diagnosis in these cases. I find that trigeminal‐mediated headshaking is often the definitive diagnosis, and the article covers the current published treatment options, highlighting the latest advances.
Diagnosing and treating skin diseases in goats: an update
Authors: Corke Murray , Matthews John
Published: May 2018

Skin disease in goats is not uncommon, and many skin diseases have been reported in the UK goat population (Jackson 1986). However, the recent globalisation of trade in animals and animal products has resulted in incursions of novel diseases into Europe, some of which are potential threats to goat herds in the UK. This article focuses on diseases that occur commonly, those presenting particular diagnostic or therapeutic difficulties, and those that appear to be current threats to the UK goat herds.
CS_TOTR: A new vertex centrality method for directed signed networks based on status theory
Authors: Ma Yue , Liu Min , Zhang Peng , Qi Xingqin
Published: May 2018

Measuring the importance (or centrality) of vertices in a network is a significant topic in complex network analysis, which has significant applications in diverse domains, for example, disease control, spread of rumors, viral marketing and so on. Existing studies mainly focus on social networks with only positive (or friendship) relations, while signed networks with also negative (or enemy) relations are seldom studied. Various signed networks commonly exist in real world, e.g. a network indicating friendship/enmity, love/hate or trust/mistrust relationships. In this paper, we propose a new centrality method named CS_TOTR to give a ranking of vertices in directed signed networks. To design this new method, we use the “status theory” for signed networks, and also adopt the vertex ranking algorithm for a tournament and the topological sorting algorithm for a general directed graph. We apply this new centrality method on the famous Sampson Monastery dataset and obtain a convincing result which shows its validity.
Measurement of surface shear stress vector beneath high-speed jet flow using liquid crystal coating
Authors: Wang Cheng-Peng , Zhao Ji-Song , Jiao Yun , Cheng Ke-Ming
Published: May 2018

The shear-sensitive liquid crystal coating (SSLCC) technique is investigated in the high-speed jet flow of a micro-wind-tunnel. An approach to measure surface shear stress vector distribution using the SSLCC technique is established, where six synchronous cameras are used to record the coating color at different circumferential view angles. Spatial wall shear stress vector distributions on the test surface are obtained at different velocities. The results are encouraging and demonstrate the great potential of the SSLCC technique in high-speed wind-tunnel measurement.
Matter–antimatter asymmetry and other cosmological puzzles via running vacuum cosmologies
Authors: Lima J. A. S. , Singleton D.
Published: May 2018

Current astronomical observations are successfully explained by the present cosmological paradigm based on the concordance model ([Formula: see text]CDM + Inflation). However, such a scenario is composed of a heterogeneous mix of ingredients for describing the different stages of cosmological evolution. Particularly, it does not give a unified explanation connecting the early- and late-time accelerating inflationary regimes which are separated by many aeons. Other challenges to the concordance model include: a singularity at early times or the emergence of the universe from the quantum gravity regime, the “graceful” exit from inflation to the standard radiation phase, as well as, the coincidence and cosmological constant problems. We show here that a simple running vacuum model or a time-dependent vacuum may provide insight on some of the above open questions (including a complete cosmic history), and also can explain the observed matter–antimatter asymmetry just after the initial deflationary period.