bluuebunny/crossref_metadata_2025 huggingface dataset:
Pharmacokinetics and Pharmacodynamics of Low-, Intermediate-, and High-Dose Landiolol and Esmolol During Long-Term Infusion in Healthy Whites
Authors: Krumpl Günther , Ulč Ivan , Trebs Michaela , Kadlecová Pavla , Hodisch Juri , Maurer Gabriele , Husch Bernhard
Published: November 2017

The pharmacokinetics, pharmacodynamics, safety, and tolerability of long-term administration of esmolol and landiolol, a new fast-acting cardioselective β-blocker, were compared for the first time in Caucasian subjects in a prospective clinical trial. Twelve healthy volunteers received landiolol and esmolol by continuous infusion for 24 hours in a randomized crossover study using a dose-escalation regimen. Blood concentrations of drugs and metabolites, heart rate, blood pressure, ECG parameters, and tolerability were observed for 30 hours and compared. Drug blood concentrations and areas under the curve were dose-proportional. The half life of landiolol (4.5 minutes) was significantly shorter than that of esmolol (6.9 minutes). Volume of distribution and total clearance were lower for landiolol. Heart rate reduction was faster and more pronounced with landiolol and retained throughout the administration period; effects on blood pressure were not different. Landiolol turned out to be superior to esmolol with respect to pharmacokinetic and pharmacodynamic profile and local tolerability.
REDUCED GANGLION CELL VOLUME ON OPTICAL COHERENCE TOMOGRAPHY IN PATIENTS WITH GEOGRAPHIC ATROPHY
Authors: Ramkumar Hema L. , Nguyen Brian , Bartsch Dirk-Uwe , Saunders Luke J. , Muftuoglu Ilkay Kilic , You Qisheng , Freeman William R.
Published: November 2017

Purpose:

Geographic atrophy (GA) is the sequelae of macular degeneration. Automated inner retinal analysis using optical coherence tomography is flawed because segmentation software is calibrated for normal eyes. The purpose of this study is to determine whether ganglion cell layer (GCL) volume is reduced in GA using manual analysis.

Methods:

Nineteen eyes with subfoveal GA and 22 controls were selected for morphometric analyses. Heidelberg scanning laser ophthalmoscope optical coherence tomography images of the optic nerve and macula were obtained, and the Viewing Module was used to manually calibrate retinal layer segmentation. Retinal layer volumes in the central 3-mm and surrounding 6-mm diameter were measured. Linear mixed models were used for statistics.

Results:

The GCL volume in the central 3 mm of the macula is less (P = 0.003), and the retinal nerve fiber layer volume is more (P = 0.02) in patients with GA when compared with controls. Ganglion cell layer volume positively correlated with outer nuclear layer volume (P = 0.020).

Conclusion:

The patients with geographic atrophy have a small significant loss of the GCL. Ganglion cell death may precede axonal loss, and increased macular retinal nerve fiber layer volumes are not indicative of GCL volume. Residual ganglion cell stimulation by interneurons may enable vision in patients with GA.
SCLERAL SELF-INDENTATION DURING CHANDELIER-ASSISTED PERIPHERAL VITRECTOMY UNDER AIR FOR RHEGMATOGENOUS RETINAL DETACHMENT
Authors: Ewais Wael A. , Nossair Ashraf A. , Aly Lamia S.
Published: November 2017

Purpose:

To evaluate incidence of iatrogenic retinal breaks in eyes for whom self-indentation during chandelier-assisted peripheral vitrectomy under air, for primary retinal detachment, had been performed compared with eyes for whom a nonindentation chandelier-assisted peripheral vitrectomy under air had been performed.

Methods:

Retrospective cohort study. One hundred and thirty eyes with primary rhegmatogenous retinal detachment were identified. All the patients had undergone a chandelier-assisted peripheral vitrectomy under air. Scleral self-indentation had been used in 68 eyes (study group; indentation), whereas nonindentation had been used in 62 eyes (comparison; nonindentation). Outcome variables included the following: trimming-induced retinal breaks, retinal redetachment rate, final logMAR best-corrected visual acuity, and intraoperative complications.

Results:

The number of eyes with trimming-induced retinal break was statistically less in indentation group than in nonindentation group (0/68 and 3/62 eyes, 0% and 4.8%, respectively) (P = 0.04). Redetachment was observed in one eye (indentation) (1/68) and in three eyes (nonindentation) (3/62) (P = 0.267). There was no statistically significant difference in logMAR best-corrected visual acuity between both groups (P = 0.229). Chandelier repositioning was needed in 22 eyes (indentation) compared with 46 eyes (nonindentation) (P < 0.001).

Conclusion:

Self-indentation, during chandelier-assisted peripheral vitrectomy under air, enables complete trimming of the vitreous base without causing iatrogenic retinal breaks, with a higher retinal reattachment rate, and with less need for chandelier repositioning than with nonindentation approach. By contrast with previous reports, we consider scleral self-indentation as an advantage for chandelier air vitrectomy.
Mechanical Properties of Contact Lens Materials
Authors: Kim Eon , Saha Mou , Ehrmann Klaus
Published: November 2017

Objectives:

To evaluate the mechanical properties of commonly available soft contact lens materials and compare results using custom-built MicroTensometer.

Methods:

The Young modulus, parameters for stress relaxation, and toughness of 18 types of single vision soft contact lenses were measured using custom-built MicroTensometer. Five lenses of each type were soaked in standard phosphate buffered saline and measured at a temperature of 35°C. Each lens was flattened and sliced into a rectangular strip sample using two parallel blades.

Results:

The Acuvue Moist 1-Day and SofLens Daily lenses measured lowest moduli, whereas Air Optix Night & Day Aqua and Premio measured the highest. The measured moduli for silicone hydrogel materials were generally higher compared with the hydrogels except for Dailies AquaComfort Plus. The exponential curve fitted over the decay in stress showed a consistent time constant of approximately 10 sec for most lens types measured. However, the amplitude constant varied from 2.84% for SofLens Daily to 22.39% for Acuvue TruEye 1-Day. The toughness results showed that Dailies AquaComfort Plus is strong but not necessarily tough.

Conclusions:

The mechanical properties of commonly prescribed soft contact lens materials were measured using a dedicated instrument. Its reliability was demonstrated, and modulus results were compared against published data from manufacturers and other research groups. Agreement was generally good, with only a few exceptions exceeding 15% difference. The more recently released silicone hydrogel lens types have reduced modulus, approaching that of medium or high water content hydrogel materials.
Topographic Relationship Between Optic Disc Torsion and ß-Zone Peripapillary Atrophy in the Myopic Eyes of Young Patients With Glaucomatous-appearing Visual Field Defects
Authors: Lee Jiyun , Lee Jong Eun , Kwon Junki , Shin Joong Won , Kook Michael S.
Published: November 2017

Purpose:

The purpose of this study was to assess the topographic correlation between optic disc torsion (ODT) and beta-zone peripapillary atrophy (β-PPA) in young patients with myopia and glaucomatous-appearing visual field defects (VFDs).

Patients and Methods:

We consecutively recruited 110 eyes of 110 young patients with myopia and glaucomatous-appearing VFDs. Retinal nerve fiber layer (RNFL) and macular ganglion cell inner plexiform layer (mGCIPL) thicknesses were measured to compare between the groups with different ODT directions. For evaluating topographic correlation, the direction and degree of ODT and the direction and angles of β-PPA and point of maximum radial extent (PMRE) of β-PPA were measured on fundus photographs. Multivariate logistic regression analysis was performed to determine the clinical factors associated with inferior ODT direction. The relationships between torsional degree and clinical variables were evaluated using linear regression analyses.

Results:

Among the 110 eyes, 19 had superior ODT and 91 had inferior ODT. Compared with myopic eyes with superior ODT, those with inferior ODT showed less severity of glaucoma as determined by RNFL or mGCIPL thickness and had a longer axial length, greater amount of optic disc tilt, larger β-PPA angle, and higher ratio of β-PPA area and disc area. ODT direction was significantly associated with the locations of β-PPA and PMRE. Torsional degree was significantly correlated with the β-PPA angle.

Conclusions:

ODT direction showed a significant association with the locations of β-PPA and PMRE of β-PPA. Torsional degree was correlated with the β-PPA angle in the myopic eyes of young patients with glaucomatous-appearing VFDs.
Interleukin 1β inhibition contributes to the antinociceptive effects of voluntary exercise on ischemia/reperfusion-induced hypersensitivity
Authors: Ross Jessica L. , Queme Luis F. , Lamb Jordan E. , Green Kathryn J. , Ford Zachary K. , Jankowski Michael P.
Published: November 2017

Issues of peripheral circulation have been increasingly suggested as an underlying cause of musculoskeletal pain in many conditions, including sickle cell anemia and peripheral vascular disease. We have previously shown in our model of transient ischemia and reperfusion (I/R) injury of the forelimb that individual group III and IV muscle afferents display altered chemosensitivity and mechanical thresholds 1 day after injury. Functional alterations corresponded to increased evoked and spontaneous pain-related behaviors and decreased muscle strength and voluntary activity—all actions that echo clinical symptoms of ischemic myalgia. These behavioral and physiological changes appeared to originate in part from the action of increased interleukin 1β (IL1β) in the injured muscles at its upregulated IL1 receptor 1 within the dorsal root ganglion. Here, we describe that two days of voluntary wheel running prior to I/R blocks both injury-induced IL1β enhancement and the subsequent development of ischemic myalgia-like behaviors. Furthermore, the protective effects of 2 days prior exercise on the I/R-evoked increases in pain-related behaviors were also paralleled with systemic injection of the IL1 receptor antagonist during I/R. Interleukin 1 receptor antagonist treatment additionally prevented the I/R-induced changes in mechanical and chemical sensitivity of individual primary muscle afferents. Altogether, these data strengthen the evidence that transient I/R injury sensitizes group III and IV muscle afferents via increased IL1β in the muscles to stimulate ischemic myalgia development. Targeting IL1β may, therefore, be an effective treatment strategy for this insidious type of muscle pain.
Tempo-spatial discrimination is lower for noxious stimuli than for innocuous stimuli
Authors: Frahm Ken Steffen , Mørch Carsten Dahl , Andersen Ole Kæseler
Published: November 2017

The exteroceptive sensory system is responsible for sensing external stimuli in relation to time and space. The aim of this study was to investigate the tempo-spatial properties of the exteroceptive system using painful laser heat and nonpainful mechanical touch stimulation. Thirteen healthy subjects were stimulated on the volar forearm using 2 paradigms: a continuous stimulation along a line on the skin and a 2-point stimulation. The line stimulations were delivered in both the distal and proximal direction with lengths of 25, 50, 75, and 100 mm. The 2-point stimulations were assessed by simultaneous stimuli at a point-to-point distance ranging from 10 to 100 mm, in steps of 10 mm. The subjects reported the intensity (0-10 numeric rating scale, 3: pain threshold) and either direction (line stimuli) or number of perceived points (2-point stimuli). All mechanical line stimulations were reported correctly, ie, a directional discrimination threshold of less than 25 mm. For painful laser line stimulation, the directional discrimination threshold was 68.5 and 70.2 mm for distally and proximally directed stimuli, respectively. The 2-point discrimination threshold for painful laser stimulation (67.9 mm) was higher than for the mechanical stimulation (34.5 mm). Numeric rating scale increased both with line length and distance between the 2 points (linear mixed model, P < 0.001). The findings indicate that the tempo-spatial acuity of the exteroceptive system is lower for noxious stimuli than for innocuous stimuli. This is possible due to the larger receptive fields of nociceptive neurons and/or less lateral inhibition.
Instituting Vincristine Minibag Administration
Authors: Corbitt Nancy , Malick Lisa , Nishioka Jennifer , Rigdon Ann , Szoch Stephanie , Torr Peggy
Published: November 2017

The first fatal incident of wrong-route administration of vinca alkaloids occurred in 1968. Initial recommendations for practice change occurred in 2005. In 2012, 54% of oncology treatment sites had changed their practice. The authors' institution has developed a safe, adaptable, and consistent process to prepare, deliver, and administer vinca alkaloids by means of a minibag delivery. A multidisciplinary team, including representatives from the nursing and pharmacy departments, reviewed the literature and developed all processes, including staff education. Minibag administration began in August 2015, and more than 2063 doses have been administered without any extravasations. To date, the simulation strategy for education is effective, and the delivery system is safe.
Making Sense of Turmoil: How Women Reconcile Their Emotional Response to Discovery of a Potential Breast Cancer Symptom
Authors: O’Mahony Máirín , Hegarty Josephine , Rooney Vivien M.
Published: November 2017

Background

Breast cancer continues to be a major public health problem for women. Early detection and treatment are key to improved outcomes. Whereas most women seek help promptly, some postpone seeking help for self-discovered breast symptoms. Investigation of women’s help-seeking behavior and the associated influencing factors on self-discovery of a breast symptom were sought.

Objectives

The aim of this article is to report the qualitative data from women who had self-discovered a breast symptom.

Methods

Women (n = 167) with a self-discovered breast symptom (who were part of a large quantitative correlational study) commented in an open-ended question on their overall experience. Comments were analyzed using Discourse Analysis.

Results

Four linked discourses were identified: (1) “being and remaining normal,” (2) “emotion,” (3) “becoming and being abnormal,” and (4) “rationality.” A sidelined discourse of emotion is drawn on to defer taking action based on rational knowledge.

Conclusion

The tension between discourses “emotion” and “rationality” further informs our understanding of women’s help-seeking behavior following self-discovered symptoms. Findings provide a deeper understanding of the emotional aspects of women’s experience around symptom discovery.

Implications for Practice

Findings will be of benefit to all healthcare professionals involved in assessment and screening of breast changes suggestive of breast cancer. They provide a novel insight into the meaning of breast cancer, its diagnosis and treatment, and how this impacts women’s emotions as they await consultation in a breast clinic.
The Prevalence of Psychiatric Disorders and Mental Health Services Utilization by Parents and Relatives Living With Individuals With Autism Spectrum Disorders in Puerto Rico
Authors: Magallón-Neri Ernesto , Vila Dorilyz , Santiago Katyana , García Pedro , Canino Glorisa
Published: November 2017

Knowledge about prevalence rates of psychiatric disorders and mental health services use among parents and relatives of persons with autism spectrum disorder (ASD) is limited, particularly when referring to epidemiologic samples. The current study is based on an island-wide probabilistic multistage cluster sample of adult individuals (N = 3062) living in Puerto Rico. Results showed a significantly higher rate of attention deficit hyperactivity disorder and serious mental illness in parents (n = 34) or relatives (n = 34) of ASD individuals, as compared with the Puerto Rico adult population as a whole. Although not definitive because of the small sample size, the fact that the rates of mental health utilization were similar to the population sample suggests a need for greater attention by health professionals attending children with ASD to the needs for mental health services of both parents and relatives of individuals with ASD.
NordiQC Assessments of Low Molecular Weight Keratin 8/18 Immunoassays
Authors: Vyberg Mogens , Diernæs Charlotte , Røge Rasmus , Nielsen Søren ,   ISIMM-NordiQC Immunoassay Performance Assessment Series, No. 2
Published: November 2017

This paper is number 2 in a series developed through a partnership between ISIMM and NordiQC for the purpose of reporting research assessing the performance characteristics of immunoassays in an external proficiency testing program.
Vascular Access in Critically Ill Pediatric Patients With Obesity*
Authors: Halvorson Elizabeth E. , Case Doug , Skelton Joseph A. , McCrory Michael C.
Published: November 2017

Objectives:

Pediatric obesity is highly prevalent and has been associated with poor outcomes for hospitalized children. Vascular access is essential in critically ill patients. The aim of this study was to evaluate whether critically ill children with obesity are more likely to undergo vascular device insertion (excluding peripheral IV catheters) and develop related complications.

Design:

Multi-institutional retrospective observational cohort study.

Setting:

Ninety-four U.S. PICUs included in the Virtual Pediatric Systems, LLC database.

Patients:

120,272 unique patients 2 to less than 18 years old admitted between January 2009 and December 2014.

Interventions:

None.

Measurements and Main Results:

Patients were categorized into normal weight, overweight, and obese (class 1, 2, or 3); underweight patients were excluded. We used mixed-effects multivariable logistic regression to test body mass index category as an independent predictor of vascular device placement and associated complications, adjusted for age, sex, severity of illness, primary diagnosis, presence of a complex chronic condition, and admission related to trauma or surgery. A total of 73,964 devices were placed in 45,409 patients (37.8% of the total cohort received a vascular device). Most device types placed differed significantly by weight status. Subjects with class 3 obesity were less likely (odds ratio, 0.74; 95% CI, 0.67–0.81) to undergo placement of any device compared with normal weight patients. Patients with all classes of obesity were more likely to undergo placement of a peripherally inserted central catheter, with the strongest association in those with class 2 obesity (odds ratio, 1.26; 95% CI, 1.14–1.40). Class 1 and class 3 obesity were independent risk factors for developing a complication, with odds ratio of 1.31 (95% CI, 1.11–1.53) and 1.45 (95% CI, 1.07–1.99), respectively.

Conclusions:

Severe obesity is associated with decreased overall likelihood of placement of a vascular access device but increased likelihood of peripherally inserted central catheter placement and of device-related complications.
Aeromedical Transport in Children
Authors: Mortamet Guillaume , Harrington Karen , Raffin Hervé , Menat Yann , Oualha Mehdi , Renolleau Sylvain
Published: November 2017

Objective

Pediatric aeromedical transport (AT) is highly challenging. We aim to describe a series of 96 cases of children requiring medical transport in terms of the indication, modalities, and related adverse events.

Methods

In this single-center retrospective study, we included air-transported patients less than 18 years old.

Results

During the study period, 96 patients, with median age of 120 months (range, 0–204), were air transported. The reason for AT was repatriation to the home country from another hospital in 65 (67.7%), whereas for 31 (32.3%) patients, it was for transport from a hospital to another for a special procedure. The main diagnosis was trauma surgery (n = 38; 39.5%). Fifteen (15.6%) patients were mechanically ventilated. No patient sustained serious adverse events during the flight. Patients were transported by an air ambulance or by a scheduled aircraft in 55.2% and 44.8%, respectively. The median flight distance was 822 km (range, 277–9878), and most of the ATs were intra-European (n = 41; 42.7%).

Conclusion

This study describes an international experience in providing AT services for pediatric clinical cases. Among pediatric patients, the younger ones constitute a specific population, and most of them require mechanical ventilation. Therefore, the transport of these patients seems to be more appropriate in a dedicated air ambulance.
Distance Between the Distal Rectal Pouch and Perineum in Neonates of Low-Birth Weight With Imperforate Anus
Authors: Hosokawa Takahiro , Hosokawa Mayumi , Tanami Yutaka , Takahashi Hiroaki , Hattori Shinya , Sato Yumiko , Tanaka Yujiro , Kawashima Hiroshi , Oguma Eiji , Yamada Yoshitake
Published: November 2017

This study was to evaluate the correlation between birth weight and the distance between distal rectal pouch and perineum (P-P distance) and to determine a cutoff value for P-P distance to diagnose low-type imperforate anus in neonates with low-birth weight (LBW).

We included 15 neonates with LBW (mean weight, 2012 ± 470 g; range, 906–2452 g) and imperforate anus (surgically confirmed: 11 low type and 3/1 intermediate/high type), who underwent ultrasonography on the day after birth. Type of imperforate anus was defined based on the International Classification of Anorectal Anomalies. The P-P distances on ultrasonograms were measured. Pearson correlation coefficient test and receiver operating characteristic curve were used for statistical analyses.

Among all 15 neonates, nonsignificant correlation was observed between the birth weight and P-P distance (r = 0.36; P = 0.18). Mean P-P distance was 9.0 ± 6.6 mm (range, 1.0–24.0 mm) in all neonates, 5.7 ± 2.8 mm (range, 1.0–11.0 mm) in the 11 neonates with low-type imperforate anus, and 18.3 ± 9.1 mm (range, 14.0–24.0 mm) in the 4 neonates with intermediate-/high-type imperforate anus. Using cutoff P-P distance of 12.5 mm, sensitivity and specificity for diagnosis of low-type imperforate anus were 100% (11/11) and 100% (4/4), respectively.

In conclusion, nonsignificant correlation was observed between P-P distance and birth weight, and cutoff P-P distance to diagnose low-type imperforate anus was 12.5 mm. Despite the very small sample size in our study, and only 4 neonates with intermediate-/high-type imperforate anus, these findings are important because surgical management whether transperineal anoplasty or diverting colostomy is decided based on the type of imperforate anus, and P-P distance to diagnose the type of imperforate anus was feasible even in neonates with LBW.
Current Challenges in the Development of Acellular Hemoglobin Oxygen Carriers by Protein Engineering
Authors: Benitez Cardenas Andres S. , Samuel Premila P. , Olson John S.
Published: November 2017

This article reviews the key biochemical mechanisms that govern O2transport, NO scavenging, and oxidative degradation of acellular hemoglobin (Hb) and how these ideas have been used to try to develop strategies to engineer safer and more effective hemoglobin-based oxygen carriers (HBOCs). Significant toxicities due to acellular Hb have been observed after the administration of HBOCs or after the lysis of red cells, and include rapid clearance and kidney damage due to dissociation into dimers, haptoglobin binding, and macrophage activation; early O2release leading to decreased tissue perfusion in capillary beds; interference with endothelial and smooth muscle signaling due to nitric oxide (NO) scavenging; autooxidization of heme iron followed by production of reactive oxygen species; and iron overload symptoms due to hemin loss, globin denaturation, iron accumulation, and further inflammation. Protein engineering can be used to mitigate some of these side effects, but requires an in-depth mechanistic understanding of the biochemical and biophysical features of Hb that regulate quaternary structure, O2affinity, NO dioxygenation, and resistance to oxidation, hemin loss, and unfolding.
Coevolution between transposable elements and recombination
Authors: Kent Tyler V. , Uzunović Jasmina , Wright Stephen I.
Published: November 2017

One of the most striking patterns of genome structure is the tight, typically negative, association between transposable elements (TEs) and meiotic recombination rates. While this is a highly recurring feature of eukaryotic genomes, the mechanisms driving correlations between TEs and recombination remain poorly understood, and distinguishing cause versus effect is challenging. Here, we review the evidence for a relation between TEs and recombination, and discuss the underlying evolutionary forces. Evidence to date suggests that overall TE densities correlate negatively with recombination, but the strength of this correlation varies across element types, and the pattern can be reversed. Results suggest that heterogeneity in the strength of selection against ectopic recombination and gene disruption can drive TE accumulation in regions of low recombination, but there is also strong evidence that the regulation of TEs can influence local recombination rates. We hypothesize that TE insertion polymorphism may be important in driving within-species variation in recombination rates in surrounding genomic regions. Furthermore, the interaction between TEs and recombination may create positive feedback, whereby TE accumulation in non-recombining regions contributes to the spread of recombination suppression. Further investigation of the coevolution between recombination and TEs has important implications for our understanding of the evolution of recombination rates and genome structure.

This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’.
Recombination rate plasticity: revealing mechanisms by design
Authors: Stevison Laurie S. , Sefick Stephen , Rushton Chase , Graze Rita M.
Published: November 2017

For over a century, scientists have known that meiotic recombination rates can vary considerably among individuals, and that environmental conditions can modify recombination rates relative to the background. A variety of external and intrinsic factors such as temperature, age, sex and starvation can elicit ‘plastic’ responses in recombination rate. The influence of recombination rate plasticity on genetic diversity of the next generation has interesting and important implications for how populations evolve. Further, many questions remain regarding the mechanisms and molecular processes that contribute to recombination rate plasticity. Here, we review 100 years of experimental work on recombination rate plasticity conducted inDrosophila melanogaster. We categorize this work into four major classes of experimental designs, which we describe via classic studies inD. melanogaster. Based on these studies, we highlight molecular mechanisms that are supported by experimental results and relate these findings to studies in other systems. We synthesize lessons learned from this model system into experimental guidelines for using recent advances in genotyping technologies, to study recombination rate plasticity in non-model organisms. Specifically, we recommend (1) using fine-scale genome-wide markers, (2) collecting time-course data, (3) including crossover distribution measurements, and (4) using mixed effects models to analyse results. To illustrate this approach, we present an application adhering to these guidelines from empirical work we conducted inDrosophila pseudoobscura.

This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’.
What drives the evolution of condition-dependent recombination in diploids? Some insights from simulation modelling
Authors: Rybnikov Sviatoslav R. , Frenkel Zeev M. , Korol Abraham B.
Published: November 2017

While the evolutionary advantages of non-zero recombination rates have prompted diverse theoretical explanations, the evolution of essential recombination features remains underexplored. We focused on one such feature, the condition dependence of recombination, viewed as the variation in within-generation sensitivity of recombination to external (environment) and/or internal (genotype) conditions. Limited empirical evidence for its existence comes mainly from diploids, whereas theoretical models show that it only easily evolves in haploids. The evolution of condition-dependent recombination can be explained by its advantage for the selected system (indirect effect), or by benefits to modifier alleles, ensuring this strategy regardless of effects on the selected system (direct effect). We considered infinite panmictic populations of diploids exposed to a cyclical two-state environment. Each organism had three selected loci. Examining allele dynamics at a fourth, selectively neutral recombination modifier locus, we frequently observed that a modifier allele conferring condition-dependent recombination between the selected loci displaced the allele conferring the optimal constant recombination rate. Our simulations also confirm the results of theoretical studies showing that condition-dependent recombination cannot evolve in diploids on the basis of direct fitness-dependent effects alone. Therefore, the evolution of condition-dependent recombination in diploids can be driven by indirect effects alone, i.e. by modifier effects on the selected system.

This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’.
Are the effects of elevated temperature on meiotic recombination and thermotolerance linked via the axis and synaptonemal complex?
Authors: Morgan Christopher H. , Zhang Huakun , Bomblies Kirsten
Published: November 2017

Meiosis is unusual among cell divisions in shuffling genetic material by crossovers among homologous chromosomes and partitioning the genome into haploid gametes. Crossovers are critical for chromosome segregation in most eukaryotes, but are also an important factor in evolution, as they generate novel genetic combinations. The molecular mechanisms that underpin meiotic recombination and chromosome segregation are well conserved across kingdoms, but are also sensitive to perturbation by environment, especially temperature. Even subtle shifts in temperature can alter the number and placement of crossovers, while at greater extremes, structural failures can occur in the linear axis and synaptonemal complex structures which are essential for recombination and chromosome segregation. Understanding the effects of temperature on these processes is important for its implications in evolution and breeding, especially in the context of global warming. In this review, we first summarize the process of meiotic recombination and its reliance on axis and synaptonemal complex structures, and then discuss effects of temperature on these processes and structures. We hypothesize that some consistent effects of temperature on recombination and meiotic thermotolerance may commonly be two sides of the same coin, driven by effects of temperature on the folding or interaction of key meiotic proteins.

This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’.
Recombination: the good, the bad and the variable
Authors: Stapley Jessica , Feulner Philine G. D. , Johnston Susan E. , Santure Anna W. , Smadja Carole M.
Published: November 2017

Recombination, the process by which DNA strands are broken and repaired, producing new combinations of alleles, occurs in nearly all multicellular organisms and has important implications for many evolutionary processes. The effects of recombination can begood, as it can facilitate adaptation, but alsobadwhen it breaks apart beneficial combinations of alleles, and recombination is highlyvariablebetween taxa, species, individuals and across the genome. Understanding how and why recombination rate varies is a major challenge in biology. Most theoretical and empirical work has been devoted to understanding the role of recombination in the evolution of sex—comparing between sexual and asexual species or populations. How recombination rate evolves and what impact this has on evolutionary processes within sexually reproducing organisms has received much less attention. This Theme Issue focusses on how and why recombination rate varies in sexual species, and aims to coalesce knowledge of the molecular mechanisms governing recombination with our understanding of the evolutionary processes driving variation in recombination within and between species. By integrating these fields, we can identify important knowledge gaps and areas for future research, and pave the way for a more comprehensive understanding of how and why recombination rate varies.
Nanopore sequencing of complex genomic rearrangements in yeast reveals mechanisms of repeat-mediated double-strand break repair
Authors: McGinty Ryan J. , Rubinstein Rachel G. , Neil Alexander J. , Dominska Margaret , Kiktev Denis , Petes Thomas D. , Mirkin Sergei M.
Published: November 2017

Improper DNA double-strand break (DSB) repair results in complex genomic rearrangements (CGRs) in many cancers and various congenital disorders in humans. Trinucleotide repeat sequences, such as (GAA)n repeats in Friedreich's ataxia, (CTG)n repeats in myotonic dystrophy, and (CGG)n repeats in fragile X syndrome, are also subject to double-strand breaks within the repetitive tract followed by DNA repair. Mapping the outcomes of CGRs is important for understanding their causes and potential phenotypic effects. However, high-resolution mapping of CGRs has traditionally been a laborious and highly skilled process. Recent advances in long-read DNA sequencing technologies, specifically Nanopore sequencing, have made possible the rapid identification of CGRs with single base pair resolution. Here, we have used whole-genome Nanopore sequencing to characterize several CGRs that originated from naturally occurring DSBs at (GAA)n microsatellites in Saccharomyces cerevisiae. These data gave us important insights into the mechanisms of DSB repair leading to CGRs.
Crystal structures of two 1:2 dihydrate compounds of chloranilic acid with 2-carboxypyridine and 2-carboxyquinoline
Authors: Gotoh Kazuma , Ishida Hiroyuki
Published: November 2017

The crystal structure of the 1:2 dihydrate compound of chloranilic acid (systematic name: 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone) with 2-carboxypyridine (another common name: picolinic acid; systematic name: pyridine-2-carboxylic acid), namely, 2C6H5.5NO20.5+·C6HCl2O4−·2H2O, (I), has been determined at 180 K, and the structure of the 1:2 dihydrate compound of chloranilic acid with 2-carboxyquinoline (another common name: quinaldic acid; systematic name: quinoline-2-carboxylic acid), namely, 2C10H7NO2·C6H2Cl2O4·2H2O, (II), has been redetermined at 200 K. This determination presents a higher precision crystal structure than the previously published structure [Marfo-Owusu & Thompson (2014).X-ray Struct. Anal. Online,30, 55–56]. Compound (I) was analysed as a disordered structure over two states,viz.salt and co-crystal. The salt is bis(2-carboxypyridinium) chloranilate dihydrate, 2C6H6NO2+·C6Cl2O42−·2H2O, and the co-crystal is bis(pyridinium-2-carboxylate) chloranilic acid dihydrate, 2C6H5NO2·C6H2Cl2O4·2H2O, including zwitterionic 2-carboxypyridine. In both salt and co-crystal, the water molecule links the chloranilic acid and 2-carboxypyridine molecules through O—H...O and N—H...O hydrogen bonds. The 2-carboxypyridine molecules are connected into a head-to-head inversion dimer by a short O—H...O hydrogen bond, in which the H atom is disordered over two positions. Compound (II) is a 1:2 dihydrate co-crystal of chloranilic acid and zwitterionic 2-carboxyquinoline. The water molecule links the chloranilic acid and 2-carboxyquinoline molecules through O—H...O hydrogen bonds. The 2-carboxyquinoline molecules are connected into a head-to-tail inversion dimer by a pair of N—H...O hydrogen bonds.
Green business models in the construction sector: an analysis of outcomes and benefits
Authors: Abuzeinab Amal , Arif Mohammed , Qadri Mohd. Asim , Kulonda Dennis
Published: November 2017

Purpose

Green business models (GBMs) in the construction sector represent the logic of green value creation and capture. Hence, the call to examine GBMs is growing ever louder. The aim of this paper is to identify benefits of GBMs by adopting five essential elements of the GBM from the literature: green value proposition; target group; key activities; key resources (KR); and financial logic.

Design/methodology/approach

In all, 19 semi-structured interviews are conducted with construction sector practitioners and academics in the UK. Thematic analysis is used to obtain benefits of GBMs. Further, the interpretive ranking process (IRP) is used to examine which elements of the GBM have a dominant role in providing benefits to construction businesses.

Findings

The benefits are grouped into three themes: credibility/reputation benefits; financial benefits; and long-term viability benefits. The IRP model shows that the element of KR is the most important when evaluated against these three benefit themes.

Practical implications

Linking GBM elements and benefits will help companies in the construction sector to analyse the business case of embracing environmental sustainability.

Originality/value

This research is one of the few empirical academic works investigating the benefits of GBMs in the construction sector. The IRP method is a novel contribution to GBMs and construction research.
Experimental study of signal behavior for wireless communication in construction
Authors: Din Zia Ud , Bernold Leonhard E.
Published: November 2017

Purpose

The purpose of this study is to understand the effects of building components of a growing concrete structure and different building materials such as glass and steel on Wi-Fi signals propagation in a construction site. Wireless local area networks are considered effective tools to link the islands-of-communication in construction. Still, designing a Wi-Fi network that can grow with a new construction requires that one understands the performance of propagation of electromagnetic signals transmitted at 2.4 GHz.

Design/methodology/approach

This paper reviews the theoretical behavior of electromagnetic signals when signal attenuation is caused by various construction materials changing their strengths, directions and possibly leading to total absorption. The authors used a typical building layout to conduct experimental work to measure the effect of common building features and communication technologies on signal strengths.

Findings

The measured data not only confirmed the theory-based predictions but also demonstrated the complexity of predicting signal propagation when obstructions inhibit the line-of-sight “travel” of electromagnetic signals.

Originality/value

Different to other papers, the experiments were conducted outside a concrete building mimicking the situation where the transmitter is set up at the site office.
Improving teacher learning: variation in conceptions of learning study
Authors: Durden Guy
Published: November 2017

Purpose

The purpose of this paper is to identify teachers’ conceptions of learning study in order to provide the basis for an application of phenomenography/variation theory (PVT) to the improvement of teachers’ learning about learning study.

Design/methodology/approach

A phenomenographic study based on semi-structured interviews with 18 beginner teachers of business and economics in England taking part in a learning study during their initial teacher education.

Findings

The study identified five conceptions of learning study and five associated critical aspects. Results raise questions about the relationship between the process and instructional design elements of learning study.

Originality/value

The study offers a framework for exploring differences in the quality of learning studies and the relationship between teacher conceptions of learning study and the degree of conceptual change in students in a learning study. It also enables facilitator/researchers to design and manage interventions to develop teacher understanding of learning study that are consistent with the principles of PVT.
The many faces of lesson study and learning study
Authors: Wood Keith
Published: November 2017

Purpose

The purpose of this paper is to provide a review of the contributions to the current issue.

Design/methodology/approach

The paper is intended to stimulate a discussion about the nature of lesson study (LS), its use in initial teacher education (ITE) and the role of learning theory in the design of the research lesson.

Findings

The term LS was first used to describe a Japanese LS. It was seen as career-long teacher-initiated collaborative professional development through which teachers researched lesson designs to teach problem-solving and develop independent thinking skills in their students. As it has been adopted across the world, it has been adapted. This raises questions about the form and effect of LS in its various forms, about the role of learning theory in the design of research lessons and about the appropriateness of introducing LS in programmes of ITE.

Originality/value

This editorial review provides an overview of the insights and issues identified by the authors in this issue of the journal.
Supervisor motivating styles and legitimacy: moderation and mediation models
Authors: Kanat-Maymon Yaniv , Mor Yaron , Gottlieb Elinur , Shoshani Anat
Published: November 2017

Purpose

The purpose of this paper is to examine the mediating and moderating roles of perceived supervisor legitimacy in the association between perceived supervisor motivating styles and subordinate functioning. Specifically, based on Self-Determination Theory (SDT), two supervisory motivating styles were examined: the autonomy-supportive style, characterized by nurturing employees’ inner motivational resources, and the controlling style, in which supervisors pressure their employees to behave in specific manager-directed ways. Legitimacy was defined according to the Relational Model of Authority (RMA).

Design/methodology/approach

An online survey was administered to a sample of 252 employees. Moderation and mediation analyses were conducted to test the hypotheses.

Findings

The autonomy-supportive motivating style, but not the controlling style, was linked to employee work-related outcomes (i.e. job satisfaction, commitment, engagement, burnout, and depression) through perceived legitimacy. Legitimacy buffered the negative impact of the controlled orientation on burnout and depression.

Originality/value

Taken together, the results suggest that legitimacy as a resource may be enhanced by autonomy support and can also minimize the harmful consequences of controlling supervisory behaviors. The theoretical implications of integrating SDT with RMA and the practical implications of these findings are discussed.
Recent advances in sensors for early detection of pathogens causing rheumatic heart disease
Authors: Singh Swati , Kaushal Ankur , Kumar Ashok
Published: November 2017

Purpose

There is an immense concern in the international community about controlling the outburst of infectious diseases. An essential step towards diminishing it is the development of an adequate detection system. Among the huge plethora of microorganisms which may infect the human body, Streptococcus pyogenes is important one which infects the upper respiratory tract leading to sore throat, which eventually develops into rheumatic heart disease (RHD) in the absence of timely treatment. A major process in controlling the infection is to detect it at an early stage. Hence, there is a need to develop detection tools which are both rapid and reliable.

Design/methodology/approach

Different types of diagnostic methods are available for identification, but the most commonly used are culturing, staining and rapid antigen detection tests. For better sensitivity and specificity, this review describes the development of biosensor. Compared with the current available methods, which are usually cumbersome, time-consuming and expensive, this approach features sequence specificity, cost efficiency, rapid and ease of use.

Findings

This review outlines various sensors which are available for the detection of Streptococcus pyogenes which causes human RHD. The working scheme of the sensors, their sensitivity and limitation of detection has been described in the review.

Originality/value

The review fulfills an acknowledged the need to study various sensors that are available for the detection of Streptococcus pyogenes, causing human RHD.
Regime shifts shorten food chains for mesopredators with potential sublethal effects
Authors: Hempson Tessa N. , Graham Nicholas A. J. , MacNeil M. Aaron , Bodin Nathalie , Wilson Shaun K.
Published: November 2017

Predator populations are in decline globally. Exploitation, as well as habitat degradation and associated changes in prey availability are key drivers of this process of trophic downgrading. In the short term, longevity and dietary adaptability of large‐bodied consumers can mask potential sublethal effects of a changing prey base, producing a delayed effect that may be difficult to detect.

In coral reef ecosystems, regime shifts from coral‐ to algae‐dominated states caused by coral bleaching significantly alter the assemblage of small‐bodied reef fish associated with a reef. The effects of this changing prey community on reef‐associated mesopredators remains poorly understood.

This study found that the total diversity, abundance and biomass of piscivorous mesopredators was lower on regime‐shifted reefs than recovering reefs, 16 years after the 1998 mass coral bleaching event.

We used stable isotope analyses to test for habitat‐driven changes in the trophic niche occupied by a key piscivorous fishery target species on reefs that had regime‐shifted or recovered following climatic disturbance. Using morphometric indices, histology, and lipid analyses, we also investigated whether there were sublethal costs for fish on regime‐shifted reefs.

Stable isotopes demonstrated that fish from regime‐shifted reefs fed further down the food chain, compared to recovering reefs. Lower densities of hepatocyte vacuoles in fish from regime‐shifted reefs, and reduced lipid concentrations in spawning females from these reefs, indicated a reduction in energy stores, constituting a sublethal and potential delayed effect on populations.

Reduced energy reserves in mesopredators could lead to energy allocation trade‐offs, and decreased growth rates, fecundity and survivorship, resulting in potential population declines in the longer term.

A plain language summary is available for this article.
A prediction model for frequency spectrum of blast‐induced seismic wave in viscoelastic medium
Authors: Yu Chenglong , Wang Zhongqi , Han Wengong
Published: November 2017

A prediction model for frequency spectrum of blast‐induced seismic waves is established. The effect of explosive sources is considered in this model. Our model implies that the frequency spectrum of blast‐induced seismic wave is mainly influenced by the initial pressure and the adiabatic exponent of explosives. The dominant frequency increases with the decreasing of initial pressure or the increasing of adiabatic exponent. In addition, this prediction model is verified by the experiment. The error of the dominant frequency is 4%–6%. It is indicated that the proposed model in this paper can reasonably predict the frequency spectrum of blast‐induced seismic waves, and then, we can provide a better frequency spectrum by optimizing the explosion source.