bluuebunny/crossref_metadata_2025 huggingface dataset:
Gestational Diabetes and the Risk of Late Stillbirth: A Case-Control Study From England, UK
Authors: Stacey T. , Tennant P. W. G. , McCowan L. M. E. , Mitchell E. A. , Budd J. , Li M. , Thompson J. M. D. , Martin B. , Roberts D. , Heazell A. E. P.
Published: December 2019

(Abstracted from BJOG 2019;126:973–982)

A high prevalence of late-term stillbirths in the United Kingdom has prompted a study to investigate whether a relationship exists between gestational diabetes mellitus (GDM) and stillbirth. Preexisting diabetes is associated with a significant increase of 4- to 6-fold in risk of stillbirth, but the relationship between GDM and stillbirth risk is indeterminate.
A Crisis of Trust Between U.S. Medical Education and the National Board of Medical Examiners
Authors: Gesundheit Neil
Published: December 2019

This Invited Commentary is an independent opinion piece and companion to the Perspective by Carmody and Rajasekaran that appears in this issue of Academic Medicine. The National Board of Medical Examiners (NBME), a 501(c)(3) nonprofit, is a powerful gatekeeper to the medical profession in the United States. According to publicly available tax data, the NBME, which has increased its number of income-enhancing products, had revenues of $153.9 million (M) and net assets of $177.6M in 2017, earnings (revenue less expenses) of $39.7M in 2013–2017, and a highly compensated management team. Medical students are ultimately the source of nearly all the NBME’s revenue, and the NBME has contributed to the growth of medical student debt. The NBME has operated as a monopoly since its agreement in the early 1990s with the Federation of State Medical Boards to cosponsor the United States Medical Licensing Examination (USMLE). Although the NBME has developed valuable products and is ostensibly governed by a capable board, the NBME has inherent financial conflicts of interest and may be benefiting from the current “Step 1 mania” undermining undergraduate medical education. Here, the author makes 4 recommendations to reestablish the trust of the U.S. medical education community in the NBME: (1) the NBME should recuse itself from current discussions and policy-making decisions related to changes in the score reporting of the USMLE Step 1 exam; (2) the NBME should disclose and be transparent about all aspects of its finances; (3) new NBME products, changes in pricing, and changes to pass thresholds should be approved by an oversight committee, independent of the NBME; and (4) the NBME (and USMLE) should not charge students or residents for retaking any of its licensing examinations.
Timing of β-Blocker Reintroduction and the Occurrence of Postoperative Atrial Fibrillation after Cardiac Surgery
Authors: Couffignal Camille , Amour Julien , Ait-Hamou Nora , Cholley Bernard , Fellahi Jean-Luc , Duval Xavier , Costa De Beauregard Yolande , Nataf Patrick , Dilly Marie-Pierre , Provenchère Sophie , Montravers Philippe , Mentré France , Longrois Dan
Published: December 2019

Editor’s Perspective

What We Already Know about This Topic

What This Article Tells Us That Is New

Background

For cardiac surgery patients under chronic β-blocker therapy, guidelines recommend their early postoperative reintroduction to decrease the incidence of postoperative atrial fibrillation. The authors hypothesized that the timing of β-blocker reintroduction affects their effectiveness on the incidence of postoperative atrial fibrillation.

Methods

This multicenter prospective French cohort study included patients on β-blockers (more than 30 days before surgery) in sinus rhythm without a pacemaker. The primary outcome, time sequence of β-blocker reintroduction, was analyzed for 192 h after surgery. The secondary outcome, relationship between the occurrence of postoperative atrial fibrillation and timing of β-blocker reintroduction, was analyzed based on pre- and intraoperative predictors (full and selected sets) according to landmark times (patients in whom atrial fibrillation occurred before a given landmark time were not analyzed).

Results

Of 663 patients, β-blockers were reintroduced for 532 (80%) but for only 261 (39%) patients in the first 48 h after surgery. Median duration before reintroduction was 49.5 h (95% CI, 48 to 51.5 h). Postoperative atrial fibrillation or death (N = 4) occurred in 290 (44%) patients. After performing a landmark analysis to take into account the timing of β-blocker reintroduction, the adjusted odds ratios (95% CI) for predictor full and selected (increased age, history of paroxysmal atrial fibrillation, and duration of aortic cross clamping) sets for the occurrence of postoperative atrial fibrillation were: adjusted odds ratio (full) = 0.87 (0.58 to 1.32; P = 0.517) and adjusted odds ratio (selected) = 0.84 (0.58 to 1.21; P = 0.338) at 48 h; adjusted odds ratio (full) = 0.64 (0.39 to 1.05; P = 0.076) and adjusted odds ratio (selected) = 0.58 (0.38 to 0.89; P = 0.013) at 72 h; adjusted odds ratio (full) = 0.58 (0.31 to 1.07; P = 0.079) and adjusted odds ratio (selected) = 0.53 (0.31 to 0.91; P = 0.021) at 96 h.

Conclusions

β-Blockers were reintroduced early (after less than 48 h) in fewer than half of the cardiac surgery patients. Reintroduction decreased postoperative atrial fibrillation occurrence only at later time points and only in the predictor selected set model. These results are an incentive to optimize (timing, doses, or titration) β-blocker reintroduction after cardiac surgery.
MiR-361-5p exerts tumor-suppressing functions in gastric carcinoma by targeting syndecan-binding protein
Authors: Qian Bo , Zhang Daoquan , Tao Ran , Yu Gang , Jia Bengli , Ye Kun , Ma Long , Wan Shengyun , Wu Wangfei
Published: December 2019

MiR-361-5p, a tumor-related microRNA, has been reported to be implicated in the tumorigenesis and progression of diverse types of human malignancies; however, its role in gastric carcinoma remains unclear. This study aimed to explore the biological role of miR-361-5p in gastric carcinoma and clarify the potential mechanisms involved. In the present study, miR-361-5p was found to be significantly downregulated in both gastric carcinoma tissues and cell lines. Functional studies demonstrated that enhanced expression of miR-361-5p suppressed gastric carcinoma cell proliferation in vitro, inhibited tumor growth in vivo, and induced gastric carcinoma cell apoptosis. Moreover, the tumor-suppressing effects of miR-361-5p in gastric carcinoma were abrogated by the miR-361-5p inhibitor treatment. Notably, syndecan-binding protein was downregulated by miR-361-5p via direct binding to its 3′ untranslated region in gastric carcinoma cells. Furthermore, syndecan-binding protein expression was discovered to be markedly upregulated and inversely correlated with miR-361-5p expression in gastric carcinoma tissues. Mechanistic studies revealed that restoring the expression of syndecan-binding protein alleviated miR-361-5p–induced inhibitory effects on proliferation of gastric carcinoma cells. Taken together, these findings suggest that miR-361-5p functions as a tumor suppressor in gastric carcinoma by directly targeting syndecan-binding protein and that miR-361-5p might be a novel therapeutic target for gastric carcinoma.
Visualizations Integrated Into Consumer Health Technologies Support Self-management of Chronic Diseases
Authors: Lor Maichou , Backonja Uba
Published: December 2019

While chronic diseases remain a global problem, visualizations of data and information are a potential solution to assist patients with chronic disease in communication, self-management, and decision making. The purpose of this systematic review is to synthesize evidence regarding data and information visualizations integrated into consumer health informatics solutions for chronic disease management in the community. A search was conducted in CINAHL, EMBASE, Engineering Village, PsycINFO, PubMed, and Web of Science between January 1, 2007, and May 1, 2019. Studies were evaluated using the Mixed Methods Appraisal Tool. Of the 2549 published studies, six studies met inclusion criteria. Of these six studies, two used information visualizations, two used data visualizations, and two used both information and data visualizations. Graphs were the main type of visualization used. Visualizations were mainly delivered in mobile applications and were interactive. The goals of the visualizations varied across studies including to (1) improve understanding of health data, (2) improve patient-provider communication, (3) monitor chronic disease, and/or (4) improve chronic disease management. Five studies reported subjective outcomes of the visualizations (eg, perceived usability, acceptability). One study reported both subjective and objective outcomes (eg, recall) of the visualizations. Findings highlight the need for more research on data and information visualizations integrated into consumer health technologies that support chronic disease management in daily life.
Effects of Home Language Environment and Household Crowding on Early Expressive Language Development
Authors: San San Kyaw Khin , Tin Tin Sandar , Underwood Lisa , Grant Cameron
Published: December 2019

Objective:

This study examined prospective associations of the home language environment (HLE) and household crowding with expressive language development in 2-year-old children using the data from the Growing Up in New Zealand study, a population-based prospective cohort study.

Methods:

A total of 5960 children were included. The HLE (playing games, talking in everyday activities, playing with toys, singing songs, and reading books) and household crowding were measured when the children were 9 months old. Language development was assessed using the MacArthur-Bates Communicative Development Inventories (CDIs)—II short form (A) at age 2 years. Maternal and child characteristics were measured antenatally and when the children were 9 months old.

Results:

Each HLE activity was associated with higher language scores. A high HLE score, defined as doing at least 3 of the 5 HLE activities at least once daily, was associated with an increase in the language score of 6.31 units (95% confidence interval [CI] 5.00 to 7.62, p < 0.0001). The effect of the HLE was less pronounced in more crowded homes (coefficient = −2.24, 95% CI −0.47 to 4.97, p = 0.106) compared with less crowded homes with at least one other child (coefficient = 6.19, 95% CI 4.28 to 8.10, p < 0.0001) or with no other children (coefficient = 8.19, 95% CI 5.69 to 10.70, p < 0.0001).

Conclusion:

These findings underscore the need to consider various aspects of the home environment in future interventions aiming to facilitate language development in young children.
MSH6 gene pathogenic variant identified in familial pancreatic cancer in the absence of colon cancer
Authors: Mannucci Alessandro , Zuppardo Raffaella A. , Crippa Stefano , Carrera Paola , Patricelli Maria G. , Russo Raucci Annalisa , Calabrese Federica , Lazarevic Dejan , Giannese Francesca , Tonon Giovanni , Ferrari Maurizio , Testoni Pier A. , Cavestro Giulia Martina
Published: December 2019

Objectives

Lynch syndrome is characterized by pathogenetic variants in the mismatch repair genes and autosomal dominant inheritance with incomplete penetrance. Lynch syndrome is characterized by colorectal and, with lesser and variable extent, extracolonic cancers. We describe a family with MSH6-dependent Lynch syndrome and familial pancreatic cancer and other tumours (gastric and endometrial), in the absence of colorectal neoplasia.

Methods

Patients were analysed by sequencing, Next Generation or Sanger, to identify germinal pathogenic variants in hereditary cancer genes.

Results

We identified the MSH6 gene pathogenic variant c.2194C>T, p.(Arg732Ter) in a family with hereditary pancreatic cancer without diagnosed cases of colorectal adenocarcinoma. Seven family members were affected by the MSH6 pathogenic variant. Three had pancreatic adenocarcinoma at 65, 57 and 44 years; one had endometrial cancer at 36 years. None of the remaining three subjects (75, 45 and 17 years old) had developed any cancer yet.

Conclusions

Lynch syndrome should be suspected in families with familial pancreatic cancer, even in the absence of colon cancers. Specifically, our observation supports the association between the MSH6 c.2194C>T pathogenic variant and extracolonic tumours and it suggests that MSH6 pathogenic variants are associated with familial pancreatic cancer more frequently than assumed.
Hepatitis C virus-microelimination program and patient trajectories after hepatitis C virus cure in an outpatient HIV clinical unit
Authors: Lions Caroline , Laroche Helene , Zaegel-Faucher Olivia , Ressiot Emmanuelle , Bregigeon Sylvie , Geneau de Lamarliere Perrine , Solas Caroline , Tamalet Catherine , Pieve Marie-Ange , Ritleng Anne-Suzel , Debreux Caroline , Ivanova Alena , Obry-Roguet Veronique , Carrieri Patrizia , Poizot-Martin Isabelle
Published: December 2019

Objective

Treatment recommendations for hepatitis C now make no distinction between HIV/HCV-coinfected and HCV-monoinfected patients. The largest challenge remained lack of effective models to eliminate HCV in people living with HIV. We report the results of a microelimination program evaluating the possibility of eradicating HCV in an HIV-outpatient clinical unit within 12 months.

Methods

This HCV-microelimination program began in February 2016 in an unit following approximately 1000 HIV-infected patients and combined screening and therapeutic components according to the French guideline. A nested cohort study evaluating the impact of HCV cure on different health outcomes was conducted through self-administered questionnaires and using generalized mixed models.

Results

Among 601 patients eligible for HCV serological testing, 445 were evaluated, and two HCV acute infections were diagnosed. Among the 151 patients eligible for HCV RNA quantification, 119 were evaluated, and one reinfection with HCV was diagnosed. Among the 110 patients eligible for direct-acting antiviral treatment, 51 (46.4%) initiated treatment within the 12 months program, and 35 (31.8%) after. Sustained virologic response (SVR) rate was 96.1%, and two treatments failed. At least one self-reported symptom was declared by 72.5% (n = 29) of patients. Positive impact of HCV cure was observed on various markers of physical and mental health as well as on health habits.

Conclusion

Our program should be considered as a proof of concept, which confirmed the feasibility of a HCV-microelimination program at the scale of an HIV clinical unit. However, 12 months were not sufficient to achieve our objective despite the specific organization.
Ring removal: an illustrated summary of the literature
Authors: Asher Christian M. , Fleet Malik , Bystrzonowski Nicola
Published: December 2019

Objectives:

The inability to remove a ring from a finger is a common presentation to Emergency Departments in addition to Orthopaedic and Plastic Surgery Units. This is often complicated by factors including trauma and infection, leading to a superimposed tourniquet effect by the ring, strangulating the subcutaneous tissues. The threat of neurovascular compromise favours early removal of the ring to limit associated morbidity. This article illustrates the common methods within the literature. We offer assessing clinicians an illustrated summary of techniques for removing an incarcerated ring from an extremity and summarise notable considerations to be acknowledged at time of assessment and ring removal.

Methods:

A literature search using PubMed and Medline was performed to identify all articles written in English on ring removal.

Results:

The 12 publications included in this illustrated review describing techniques for removal of an incarcerated ring were published between 1991 and 2018 and include modifications to overcome difficulties due to the composition of the ring or severity of the ring incarceration and penile/scrotal ring removal.

Conclusion:

The ring removal techniques are ring preserving or destructive. The technique used depends on factors including the extent of associated trauma to the digit, evidence of strangulation, ring composition, patient preference and equipment availability. Before an attempt at ring removal, high arm elevation, indirect ice compression of the digit and adequate analgesia maximise chances of success. In cases of strangulation, emergent referral to a specialist is indicated for removal and further management.
Polydactyly a review and update of a common congenital hand difference
Authors: Wessel Lauren E. , Daluiski Aaron , Trehan Samir K.
Published: December 2019

Purpose of review

The purpose of this review is to describe various forms of hand polydactyly and their different treatment approaches. Hand polydactyly is commonly classified as ulnar (small finger) or radial (thumb). Polydactyly can be sporadic, genetic, and/or associated with syndromic conditions.

Recent findings

Both ulnar and radial polydactyly can be surgically treated to optimize hand aesthetics and function. Timing of surgery is based on multiple factors, most notably including safety of anesthesia and socialization of the affected child. The pediatrician should be aware of potential associated conditions, such as chondroectodermal dysplasia or Ellis-van Creveld syndrome for ulnar polydactyly.

Polydactyly is a common congenital hand difference and can be broadly be classified by radial or ulnar involvement. Polydactyly warrants hand surgical referral, as surgical treatment is often indicated. Pediatricians should be aware of treatment options, as well as of commonly associated anomalies and syndromes.
Lifetime Syphilis Prevalence and Associated Risk Factors Among Female Prisoners in Brazil
Authors: da Silva Santana Rosane , Kerr Ligia , Mota Rosa Salani , Kendall Carl , Rutherford George , McFarland Willi
Published: December 2019

Background

In 2016, approximately 42,000 women were incarcerated in Brazil. The objectives of this study were to measure the lifetime prevalence of syphilis and sociodemographic and behavior correlates of antibody positivity among female prisoners in Brazil.

Methods

We conducted a cross-sectional survey of 1327 incarcerated women in 2014 to 2015 sampled through a multistage cluster design to represent the penitentiary system throughout Brazil. A rapid treponemal antibody test approved by the Ministry of Health (Rapid Test DPP Sífilis Bio-Manguinhos) was used to detect lifetime history of infection. Analyses were adjusted using weights based on the inverse of the product of the probabilities of the sampling units at each stage of the design. Variables significantly associated with syphilis infection at P < 0.05 in multivariate analyses were retained in the final model.

Results

Prevalence of syphilis antibody among female prisoners in Brazil was 11.6% (95% confidence interval [CI], 9.8%–13.8%). Higher syphilis prevalence was associated with black/Afro-Brazilian or mixed race/ethnicity (adjusted odds ratio [AOR], 1.78; 95% CI, 1.10–2.87), homelessness (AOR, 4.58; 95% CI, 2.78–7.56), abortion (AOR, 1.56; 95% CI, 1.02–2.38), and sexual violence (AOR, 1.59; 95% CI, 1.01–2.49). Syphilis prevalence was lower among women who had received condoms in school (AOR, 0.28; 95% CI, 0.08–1.00) as a marker for reproductive health education.

Conclusions

Women within the vast Brazilian prison system demonstrate a high lifetime cumulative incidence of syphilis. Our data advocate for increased screening and treatment of syphilis of incarcerated women and help identify women at higher risk within the prison system and within their communities of origin.
Postoperative Horner Syndrome After Lung Transplantation
Authors: Go Jonathan A. , Vickers Aroucha , Kaleekal Thomas S. , Beaver Hilary A. , Lee Andrew G.
Published: December 2019

Background:

Horner syndrome arises from a disruption along the oculosympathetic efferent chain and can be caused by a variety of pathological and iatrogenic etiologies. We present 3 cases of postoperative Horner syndrome after bilateral lung transplantation.

Methods:

The electronic health records of 3 patients with iatrogenic Horner syndrome after lung transplantation were examined, including notes from each patient's medical history, operative and postoperative records, and ophthalmology consultation results. A literature review was performed.

Results:

All 3 of our patients displayed anisocoria and ptosis, symptoms consistent with Horner syndrome, and the patients from Cases 1 and 2 showed reversal of anisocoria after an application of topical apraclonidine.

Conclusions:

Ophthalmologists should be aware of the risk of Horner syndrome after lung transplantation.
Collective decision-making appears more egalitarian in populations where group fission costs are higher
Authors: Herbert-Read J. E. , Wade A. S. I. , Ramnarine I. W. , Ioannou C. C.
Published: December 2019

Collective decision-making is predicted to be more egalitarian in conditions where the costs of group fission are higher. Here, we ask whether Trinidadian guppies (
Poecilia reticulata
) living in high or low predation environments, and thereby facing differential group fission costs, make collective decisions in line with this prediction. Using a classic decision-making scenario, we found that fish from high predation environments switched their positions within groups more frequently than fish from low predation environments. Because the relative positions individuals adopt in moving groups can influence their contribution towards group decisions, increased positional switching appears to support the prediction of more evenly distributed decision-making in populations where group fission costs are higher. In an agent-based model, we further identified that more frequent, asynchronous updating of individuals' positions could explain increased positional switching, as was observed in fish from high predation environments. Our results are consistent with theoretical predictions about the structure of collective decision-making and the adaptability of social decision-rules in the face of different environmental contexts.
The dynamics underlying avian extinction trajectories forecast a wave of extinctions
Authors: Monroe Melanie J. , Butchart Stuart H. M. , Mooers Arne O. , Bokma Folmer
Published: December 2019

Population decline is a process, yet estimates of current extinction rates often consider just the final step of that process by counting numbers of species lost in historical times. This neglects the increased extinction risk that affects a large proportion of species, and consequently underestimates the effective extinction rate. Here, we model observed trajectories through IUCN Red List extinction risk categories for all bird species globally over 28 years, and estimate an overall effective extinction rate of 2.17 × 10
−4
/species/year. This is six times higher than the rate of outright extinction since 1500, as a consequence of the large number of species whose status is deteriorating. We very conservatively estimate that global conservation efforts have reduced the effective extinction rate by 40%, but mostly through preventing critically endangered species from going extinct rather than by preventing species at low risk from moving into higher-risk categories. Our findings suggest that extinction risk in birds is accumulating much more than previously appreciated, but would be even greater without conservation efforts.
Canine sense of quantity: evidence for numerical ratio-dependent activation in parietotemporal cortex
Authors: Aulet Lauren S. , Chiu Veronica C. , Prichard Ashley , Spivak Mark , Lourenco Stella F. , Berns Gregory S.
Published: December 2019

The approximate number system (ANS), which supports the rapid estimation of quantity, emerges early in human development and is widespread across species. Neural evidence from both human and non-human primates suggests the parietal cortex as a primary locus of numerical estimation, but it is unclear whether the numerical competencies observed across non-primate species are subserved by similar neural mechanisms. Moreover, because studies with non-human animals typically involve extensive training, little is known about the spontaneous numerical capacities of non-human animals. To address these questions, we examined the neural underpinnings of number perception using awake canine functional magnetic resonance imaging. Dogs passively viewed dot arrays that varied in ratio and, critically, received no task-relevant training or exposure prior to testing. We found evidence of ratio-dependent activation, which is a key feature of the ANS, in canine parietotemporal cortex in the majority of dogs tested. This finding is suggestive of a neural mechanism for quantity perception that has been conserved across mammalian evolution.
Edward Osmund Royle Reynolds CBE. 3 February 1933—24 April 2017
Authors: Rivers Rodney P. A.
Published: December 2019

Edward Osmund Royle Reynolds was the founding father of neonatal medicine in the United Kingdom and a major leader in the field worldwide; he was a key advisor to government for a decade. He was one of the first paediatricians to specialize in the care of the newborn. He brought to the field a new emphasis on scientific medicine and intellectual rigour with an adventurous investigative and collaborative spirit. Known as Os by his colleagues, he inspired a team of clinicians and scientists who contributed to major advances in our understanding of lung disease in preterm infants and of neurological insults arising in the perinatal period that have contributed to the markedly improved survival and developmental outcomes observed in the twenty-first century compared with those of the 1950s and 1960s. The whole-body cooling, now widely utilized in the management of perinatal asphyxia, owes its introduction to the ground-breaking research utilizing magnetic resonance spectroscopy in animal and newborn studies initiated by Os. His enthusiasm for new ideas was often in evidence as was the breadth of his interests, knowledge and support. His wider influence is his legacy of the reports to government in which he was involved and is seen today in the National Neonatal Audit Programme run by the Royal College of Paediatrics and Child Health since 2006.
Free-energy-based framework for early forecasting of stem cell differentiation
Authors: Suresh H. , Shishvan S. S. , Vigliotti A. , Deshpande V. S.
Published: December 2019

Commitment of stem cells to different lineages is inherently stochastic but regulated by a range of environmental bio/chemo/mechanical cues. Here, we develop an integrated stochastic modelling framework for predicting the differentiation of hMSCs in response to a range of environmental cues, including sizes of adhesive islands, stiffness of substrates and treatment with ROCK inhibitors in both growth and mixed media. The statistical framework analyses the fluctuations of cell morphologies over approximately a 24 h period after seeding the cells in the specific environment and uses the cytoskeletal free-energy distribution to forecast the lineage the hMSCs will commit to. The cytoskeletal free energy which succinctly parametrizes the biochemical state of the cell is shown to capture hMSC commitment over a range of environments while simple morphological factors such as cell shape, tractions on their own are unable to correlate with lineages hMSCs adopt.
Scaling of the performance of insect-inspired passive-pitching flapping wings
Authors: Sum Wu Kit , Nowak Jerome , Breuer Kenneth S.
Published: December 2019

Flapping flight using passive pitch regulation is a commonly used mode of thrust and lift generation in insects and has been widely emulated in flying vehicles because it allows for simple implementation of the complex kinematics associated with flapping wing systems. Although robotic flight employing passive pitching to regulate angle of attack has been previously demonstrated, there does not exist a comprehensive understanding of the effectiveness of this mode of aerodynamic force generation, nor a method to accurately predict its performance over a range of relevant scales. Here, we present such scaling laws, incorporating aerodynamic, inertial and structural elements of the flapping-wing system, validating the theoretical considerations using a mechanical model which is tested for a linear elastic hinge and near-sinusoidal stroke kinematics over a range of scales, hinge stiffnesses and flapping frequencies. We find that suitably defined dimensionless parameters, including the Reynolds number,Re, the Cauchy number,Ch, and a newly defined ‘inertial-elastic’ number, IE, can reliably predict the kinematic and aerodynamic performance of the system. Our results also reveal a consistent dependency of pitching kinematics on these dimensionless parameters, providing a connection between lift coefficient and kinematic features such as angle of attack and wing rotation.
A minimal computational model for three-dimensional cell migration
Authors: Cao Yuansheng , Ghabache Elisabeth , Miao Yuchuan , Niman Cassandra , Hakozaki Hiroyuki , Reck-Peterson Samara L. , Devreotes Peter N. , Rappel Wouter-Jan
Published: December 2019

During migration, eukaryotic cells can continuously change their three-dimensional morphology, resulting in a highly dynamic and complex process. Further complicating this process is the observation that the same cell type can rapidly switch between different modes of migration. Modelling this complexity necessitates models that are able to track deforming membranes and that can capture the intracellular dynamics responsible for changes in migration modes. Here we develop an efficient three-dimensional computational model for cell migration, which couples cell mechanics to a simple intracellular activator–inhibitor signalling system. We compare the computational results to quantitative experiments using the social amoebaDictyostelium discoideum. The model can reproduce the observed migration modes generated by varying either mechanical or biochemical model parameters and suggests a coupling between the substrate and the biomechanics of the cell.
Oriented suspension mechanics with application to improving flow linear dichroism spectroscopy
Authors: Cupples G. , Smith D. J. , Hicks M. R. , Dyson R. J.
Published: December 2019

Flow linear dichroism is a biophysical spectroscopic technique that exploits the shear-induced alignment of elongated particles in suspension. Motivated by the broad aim of optimizing the sensitivity of this technique, and more specifically by a hand-held synthetic biotechnology prototype for waterborne-pathogen detection, a model of steady and oscillating pressure-driven channel flow and orientation dynamics of a suspension of slender microscopic fibres is developed. The model couples the Fokker–Planck equation for Brownian suspensions with the narrow channel flow equations, the latter modified to incorporate mechanical anisotropy induced by the particles. The linear dichroism signal is estimated through integrating the perpendicular components of the distribution function via an appropriate formula which takes the biaxial nature of the orientation into account. For the specific application of pathogen detection via binding of M13 bacteriophage, it is found that increases in the channel depth are more significant in improving the linear dichroism signal than increases in the channel width. Increasing the channel depth to 2 mm and pressure gradient to 5 × 104 Pa m−1essentially maximizes the alignment. Oscillating flow can produce nearly equal alignment to steady flow at appropriate frequencies, which has significant potential practical value in the analysis of small sample volumes.
Wave polarization and dynamic degeneracy in a chiral elastic lattice
Authors: Carta G. , Jones I. S. , Movchan N. V. , Movchan A. B.
Published: December 2019

This paper addresses fundamental questions arising in the theory of Bloch–Floquet waves in chiral elastic lattice systems. This area has received a significant attention in the context of ‘topologically protected’ waveforms. Although practical applications of chiral elastic lattices are widely appreciated, especially in problems of controlling low-frequency vibrations, wave polarization and filtering, the fundamental questions of the relationship of these lattices to classical waveforms associated with longitudinal and shear waves retain a substantial scope for further development. The notion of chirality is introduced into the systematic analysis of dispersive elastic waves in a doubly-periodic lattice. Important quantitative characteristics of the dynamic response of the lattice, such as lattice flux and lattice circulation, are used in the analysis along with the novel concept of ‘vortex waveforms’ that characterize the dynamic response of the chiral system. We note that the continuum concepts of pressure and shear waves do not apply for waves in a lattice, especially in the case when the wavelength is comparable with the size of the elementary cell of the periodic structure. Special critical regimes are highlighted when vortex waveforms become dominant. Analytical findings are accompanied by illustrative numerical simulations.
The influence of invariant solutions on the transient behaviour of an air bubble in a Hele-Shaw channel
Authors: Keeler Jack S. , Thompson Alice B. , Lemoult Grégoire , Juel Anne , Hazel Andrew L.
Published: December 2019

We hypothesize that dynamical systems concepts used to study the transition to turbulence in shear flows are applicable to other transition phenomena in fluid mechanics. In this paper, we consider a finite air bubble that propagates within a Hele-Shaw channel containing a depth-perturbation. Recent experiments revealed that the bubble shape becomes more complex, quantified by an increasing number of transient bubble tips, with increasing flow rate. Eventually, the bubble changes topology, breaking into multiple distinct entities with non-trivial dynamics. We demonstrate that qualitatively similar behaviour to the experiments is exhibited by a previously established, depth-averaged mathematical model and arises from the model’s intricate solution structure. For the bubble volumes studied, a stable asymmetric bubble exists for all flow rates of interest, while a second stable solution branch develops above a critical flow rate and transitions between symmetric and asymmetric shapes. The region of bistability is bounded by two Hopf bifurcations on the second branch. By developing a method for a numerical weakly nonlinear stability analysis we show that unstable periodic orbits (UPOs) emanate from the first Hopf bifurcation. Moreover, as has been found in shear flows, the UPOs are edge states that influence the transient behaviour of the system.
Interplay between cost and effectiveness in influenza vaccine uptake: a vaccination game approach
Authors: Arefin Md. Rajib , Masaki Tanaka , Kabir K. M. Ariful , Tanimoto Jun
Published: December 2019

Pre-emptive vaccination is regarded as one of the most protective measures to control influenza outbreak. There are mainly two types of influenza viruses—influenza A and B with several subtypes—that are commonly found to circulate among humans. The traditional trivalent (TIV) flu vaccine targets two strains of influenza A and one strain of influenza B. The quadrivalent (QIV) vaccine targets one extra B virus strain that ensures better protection against influenza; however, the use of QIV vaccine can be costly, hence impose an extra financial burden to society. This scenario might create a dilemma in choosing vaccine types at the individual level. This article endeavours to explain such a dilemma through the framework of a vaccination game, where individuals can opt for one of the three options: choose either of QIV or TIV vaccine or none. Our approach presumes a mean-field framework of a vaccination game in an infinite and well-mixed population, entangling the disease spreading process of influenza with the coevolution of two types of vaccination decision-making processes taking place before an epidemic season. We conduct a series of numerical simulations as an attempt to illustrate different scenarios. The framework has been validated by the so-called multi-agent simulation (MAS) approach.
Fungicide suppression of flight performance in the honeybee (
Apis mellifera
) and its amelioration by quercetin
Authors: Liao Ling-Hsiu , Wu Wen-Yen , Dad Azra , Berenbaum May R.
Published: December 2019

As a managed agricultural pollinator, the western honeybee
Apis mellifera
frequently encounters agrochemicals as contaminants of nectar and pollen. One such contaminant, the fungicide boscalid, is applied at bloom in orchards for fungal floral pathogen control. As an inhibitor of complex II in the mitochondrial electron transport chain of fungi, boscalid can potentially interfere with high energy-demanding activities of bees, including flight. We designed an indoor flight treadmill to evaluate impacts of ingesting boscalid and/or quercetin, a ubiquitous phytochemical in bee food that also affects mitochondrial respiration. Boscalid reduced the wingbeat frequencies of foragers during flight but did not alter the duration of flight. At the colony level, boscalid ingestion may thereby affect overall health by reducing forager efficiency. The consumption of quercetin, by contrast, led to higher adenosine triphosphate levels in flight muscles and a higher wingbeat frequency. Consuming the two compounds together increased wingbeat frequency, demonstrating a hitherto unrecognized mechanism by which dietary phytochemicals may act to ameliorate toxic effects of pesticides to promote honeybee health. In carrying out this work, we also introduce two methodological improvements for use in testing for pesticide effects on flight capacity—a ‘force-feeding’ to standardize flight fuel supply and a novel indoor flight treadmill.
Ordered phylogenomic subsampling enables diagnosis of systematic errors in the placement of the enigmatic arachnid order Palpigradi
Authors: Ballesteros Jesús A. , Santibáñez López Carlos E. , Kováč Ľubomír , Gavish-Regev Efrat , Sharma Prashant P.
Published: December 2019

The miniaturized arachnid order Palpigradi has ambiguous phylogenetic affinities owing to its odd combination of plesiomorphic and derived morphological traits. This lineage has never been sampled in phylogenomic datasets because of the small body size and fragility of most species, a sampling gap of immediate concern to recent disputes over arachnid monophyly. To redress this gap, we sampled a population of the cave-inhabiting species
Eukoenenia spelaea
from Slovakia and inferred its placement in the phylogeny of Chelicerata using dense phylogenomic matrices of up to 1450 loci, drawn from high-quality transcriptomic libraries and complete genomes. The complete matrix included exemplars of all extant orders of Chelicerata. Analyses of the complete matrix recovered palpigrades as the sister group of the long-branch order Parasitiformes (ticks) with high support. However, sequential deletion of long-branch taxa revealed that the position of palpigrades is prone to topological instability. Phylogenomic subsampling approaches that maximized taxon or dataset completeness recovered palpigrades as the sister group of camel spiders (Solifugae), with modest support. While this relationship is congruent with the location and architecture of the coxal glands, a long-forgotten character system that opens in the pedipalpal segments only in palpigrades and solifuges, we show that nodal support values in concatenated supermatrices can mask high levels of underlying topological conflict in the placement of the enigmatic Palpigradi.
Disrupting butterfly caterpillar microbiomes does not impact their survival and development
Authors: Phalnikar Kruttika , Kunte Krushnamegh , Agashe Deepa
Published: December 2019

Associations with gut microbes are believed to play crucial roles in the physiology, immune function, development and behaviour of insects. However, microbiome sequencing has recently suggested that butterflies are an anomaly, because their microbiomes do not show strong host- and developmental stage-specific associations. We experimentally manipulated butterfly larval gut microbiota and found that disrupting gut microbes had little influence on larval survival and development. Larvae of the butterflies
Danaus chrysippus
and
Ariadne merione
that fed on chemically sterilized or antibiotic-treated host plant leaves had significantly reduced bacterial loads, and their gut bacterial communities were disrupted substantially. However, neither host species treated this way suffered a significant fitness cost: across multiple experimental blocks, treated and control larvae had similar survival, growth and development. Furthermore, re-introducing microbes from the excreta of control larvae did not improve larval growth and survival. Thus, these butterfly larvae did not appear to rely on specialized gut bacteria for digestion, detoxification, biomass accumulation and metamorphosis. Our experiments thus show that dependence on gut bacteria for growth and survival is not a universal phenomenon across insects. Our findings also caution that strategies which target gut microbiomes may not always succeed in controlling Lepidopteran pests.
Evolution of a multifunctional trait: shared effects of foraging ecology and thermoregulation on beak morphology, with consequences for song evolution
Authors: Friedman Nicholas R. , Miller Eliot T. , Ball Jason R. , Kasuga Haruka , Remeš Vladimír , Economo Evan P.
Published: December 2019

While morphological traits are often associated with multiple functions, it remains unclear how evolution balances the selective effects of different functions. Birds' beaks function not only in foraging but also in thermoregulating and singing, among other behaviours. Studies of beak evolution abound, however, most focus on a single function. Hence, we quantified relative contributions of different functions over an evolutionary timescale. We measured beak shape using geometric morphometrics and compared this trait with foraging behaviour, climatic variables and song characteristics in a phylogenetic comparative study of an Australasian radiation of songbirds (Meliphagidae). We found that both climate and foraging behaviour were significantly correlated with the beak shape and size. However, foraging ecology had a greater effect on shape, and climate had a nearly equal effect on size. We also found that evolutionary changes in beak morphology had significant consequences for vocal performance: species with elongate-shaped beaks sang at higher frequencies, while species with large beaks sang at a slower pace. The evolution of the avian beak exemplifies how morphological traits can be an evolutionary compromise among functions, and suggests that specialization along any functional axis may increase ecological divergence or reproductive isolation along others.
The force–length–velocity potential of the human soleus muscle is related to the energetic cost of running
Authors: Bohm Sebastian , Mersmann Falk , Santuz Alessandro , Arampatzis Adamantios
Published: December 2019

According to the force–length–velocity relationships, the muscle force potential is determined by the operating length and velocity, which affects the energetic cost of contraction. During running, the human soleus muscle produces mechanical work through active shortening and provides the majority of propulsion. The trade-off between work production and alterations of the force–length and force–velocity potentials (i.e. fraction of maximum force according to the force–length–velocity curves) might mediate the energetic cost of running. By mapping the operating length and velocity of the soleus fascicles onto the experimentally assessed force–length and force–velocity curves, we investigated the association between the energetic cost and the force–length–velocity potentials during running. The fascicles operated close to optimal length (0.90 ± 0.10L0) with moderate velocity (0.118 ± 0.039Vmax[maximum shortening velocity]) and, thus, with a force–length potential of 0.92 ± 0.07 and a force–velocity potential of 0.63 ± 0.09. The overall force–length–velocity potential was inversely related (r= −0.52,p= 0.02) to the energetic cost, mainly determined by a reduced shortening velocity. Lower shortening velocity was largely explained (p< 0.001,R2= 0.928) by greater tendon gearing, shorter Achilles tendon lever arm, greater muscle belly gearing and smaller ankle angle velocity. Here, we provide the first experimental evidence that lower shortening velocities of the soleus muscle improve running economy.
Conformational flexibility in amidophosphoesters: a CSD analysis completed with two new crystal structures of (C6H5O)2P(O)X [X = NHC7H13 and N(CH2C6H5)2]
Authors: Vahdani Alviri Banafsheh , Pourayoubi Mehrdad , Abdul Salam Abdul Ajees , Nečas Marek , Lee Arie van der , Chithran Akshara , Damodaran Krishnan
Published: December 2019

The crystal structures of diphenyl (cycloheptylamido)phosphate, C19H24NO3P or (C6H5O)2P(O)(NHC7H13), (I), and diphenyl (dibenzylamido)phosphate, C26H24NO3P or (C6H5O)2P(O)[N(CH2C6H5)2], (II), are reported. The NHC7H13 group in (I) provides two significant hydrogen-donor sites in N—H...O and C—H...O hydrogen bonds, needed for a one-dimensional hydrogen-bond pattern along [100] in the crystal, while (II), with a (C6H5CH2)2N moiety, lacks these hydrogen bonds, but its three-dimensional supramolecular structure is mediated by C—H...π interactions. The conformational behaviour of the phenyl rings in (I), (II) and analogous structures from the Cambridge Structural Database (CSD) were studied in terms of flexibility, volume of the other group attached to phosphorus and packing forces. From this study, synclinal (±sc), anticlinal (±ac) and antiperiplanar (±ap) conformations were found to occur. In the structure of (II), there is an intramolecular C
ortho
—H...O interaction that imposes a +sc conformation for the phenyl ring involved. For the structures from the CSD, the +sc and ±ap conformations appear to be mainly imposed by similar C
ortho
—H...O intramolecular interactions. The large contribution of the C...H/H...C contacts (32.3%) in the two-dimensional fingerprint plots of (II) is a result of the C—H...π interactions. The differential scanning calorimetry (DSC) analyses exhibit peak temperatures (T
m) at 109 and 81 °C for (I) and (II), respectively, which agree with the strengths of the intermolecular contacts and the melting points.
Effects of the actively morphing root chord and taper on helicopter energy
Authors: Sal Firat
Published: December 2019

Purpose

The purpose of this paper presents the effects of actively morphing root chord and taper on the energy of the flight control system (i.e. FCS).

Design/methodology/approach

Via regarding previously mentioned purposes, sophisticated and realistic helicopter models are benefitted to examine the energy of the FCS.

Findings

Helicopters having actively morphing blade root chord length and blade taper consume less control energy than the ones having one of or any of passively morphing blade root chord length and blade taper.

Practical implications

Actively morphing blade root chord length and blade taper can be used for cheaper helicopter operations.

Originality/value

The main originality of this paper is applying active morphing strategy on helicopter blade root chord and blade taper. In this paper, it is also found that using active morphing strategy on helicopter blade root chord and blade taper reasons less energy consumption than using either passively morphing blade root chord length plus blade taper or not any. This causes also less fuel consumption and green environment.