bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnostic Yield and Safety of Bronchoscopist-directed Moderate Sedation With a Bolus Dose Administration of Propofol During Endobronchial Ultrasound Bronchoscopy
Authors: Khemasuwan Danai , Teerapuncharoen Krittika , Griffin David C.
Published: January 2018

Background:

The propofol use for moderate sedation (MS) during endobronchial ultrasound (EBUS) bronchoscopy is primarily restricted for use by an anesthesiologist because of safety concerns. The goals of this study were to demonstrate the safety and the diagnostic yield of the use of propofol by bronchoscopists and trained endoscopy nurses during EBUS bronchoscopy without intubation.

Methods:

We tested a bolus propofol administration protocol targeting MS for EBUS bronchoscopy. A fixed initial dose of 40 mg of propofol along with a fixed 50 mcg fentanyl dose were administered. Sedation assessment was performed every 2 minutes, and repeated bolus doses of propofol were given to maintain MS under the direction of the bronchoscopist.

Results:

A total of 122 subjects underwent EBUS bronchoscopy with a goal of MS from August 2015 to April 2017. In total, 110 subjects who underwent convex EBUS bronchoscopy under MS with propofol were included in the analysis. Median procedure duration was 57 minutes (range, 15 to 97 min). Deep sedation and agitation-related delay were occurred in 14 and 21 subjects, respectively. Hemodynamic instability and hypoxemia occurred in 23 subjects. However, there was no need for vasopressors or artificial airway placement. Median of total propofol dose per case was 560 mg. Diagnostic yield for malignancy and granuloma was 68%, and a median of 4 lymph node stations were sampled per subject. All specimens with adenocarcinoma were sufficient for genetic marker analysis. There were no major sedation-related complications.

Conclusion:

A bolus administration of propofol during EBUS bronchoscopy provided excellent adequacy of sedation and well tolerance safety profile.
The Utility of Ultrasound to Diagnose Tunnel-Tract Infection Related to Indwelling Pleural Catheters
Authors: Cardenas-Garcia Jose , Fitzpatrick Neal , Cheng George Z.
Published: January 2018

Indwelling pleural catheter (IPC) infections lead to increased morbidity and treatment failure in patients with chronic recurrent pleural effusions. Ultrasonography is a readily available diagnostic tool used by pulmonologists on a daily basis. Ultrasonography has been used to identify the etiology of indwelling peritoneal catheter obstruction, including infection of the exit site and tunnel tract. The use of ultrasonography to identify tunnel-tract infection involving IPC has not been reported. We describe the ultrasonographic characteristics of 3 cases of confirmed tunnel-tract infection and compared them with noninfected chronic IPCs. Ultrasonographic evaluation of the soft tissue tunnel tract can accurately identify fluid collections around the catheter and cuff, which is highly suggestive of tunnel-tract infection.
Intraoperative Cochlear Implant Device Testing Utilizing an Automated Remote System: A Prospective Pilot Study
Authors: Lohmann Amanda R. , Carlson Matthew L. , Sladen Douglas P.
Published: January 2018

Introduction:

Intraoperative cochlear implant device testing provides valuable information regarding device integrity, electrode position, and may assist with determining initial stimulation settings. Manual intraoperative device testing during cochlear implantation requires the time and expertise of a trained audiologist. The purpose of the current study is to investigate the feasibility of using automated remote intraoperative cochlear implant reverse telemetry testing as an alternative to standard testing.

Methods:

Prospective pilot study evaluating intraoperative remote automated impedance and Automatic Neural Response Telemetry (AutoNRT) testing in 34 consecutive cochlear implant surgeries using the Intraoperative Remote Assistant (Cochlear Nucleus CR120). In all cases, remote intraoperative device testing was performed by trained operating room staff. A comparison was made to the “gold standard” of manual testing by an experienced cochlear implant audiologist. Electrode position and absence of tip fold-over was confirmed using plain film x-ray.

Results:

Automated remote reverse telemetry testing was successfully completed in all patients. Intraoperative x-ray demonstrated normal electrode position without tip fold-over. Average impedance values were significantly higher using standard testing versus CR120 remote testing (standard mean 10.7 kΩ, SD 1.2 vs. CR120 mean 7.5 kΩ, SD 0.7, p < 0.001). There was strong agreement between standard manual testing and remote automated testing with regard to the presence of open or short circuits along the array. There were, however, two cases in which standard testing identified an open circuit, when CR120 testing showed the circuit to be closed. Neural responses were successfully obtained in all patients using both systems. There was no difference in basal electrode responses (standard mean 195.0 μV, SD 14.10 vs. CR120 194.5 μV, SD 14.23; p = 0.7814); however, more favorable (lower μV amplitude) results were obtained with the remote automated system in the apical 10 electrodes (standard 185.4 μV, SD 11.69 vs. CR120 177.0 μV, SD 11.57; p value < 0.001).

Conclusion:

These preliminary data demonstrate that intraoperative cochlear implant device testing using a remote automated system is feasible. This system may be useful for cochlear implant programs with limited audiology support or for programs looking to streamline intraoperative device testing protocols. Future studies with larger patient enrollment are required to validate these promising, but preliminary, findings.
Quality in Postoperative Patient Handover
Authors: Reine Elizabeth , Ræder Johan , Manser Tanja , Småstuen Milada C. , Rust⊘en Tone
Published: January 2018

Background:

A safe and efficient patient handover is important to ensure high-quality patient care and reduce the risk of patient harm. Few studies have explored handover activities beyond information transfer.

Purpose:

The aims were to assess overall postoperative handover quality and relate quality assessments to handover circumstances, conduct, and teamwork and to compare transferring and receiving nurses' evaluations of handover quality.

Method:

This was a cross-sectional study using the Norwegian Handover Quality Rating Form (N-HQRF). In addition, data were collected on nurses' evaluations of the patient condition, handover preparation, and participating nurses' clinical experience.

Results:

Although total perceived handover quality was high in a large majority of cases, there were significant differences between transferring and receiving nurses' evaluations of the same handover. Lower-quality handovers had a higher frequency of time pressure, uncertainty, and patient-related problems.

Conclusion:

The findings point to the need to assess handover quality in a wider perspective. Handover circumstances might impact handover quality and should be considered when procedures for handover quality are designed and implemented.
Pulmonary Dead Space Fraction and Extubation Success in Children After Cardiac Surgery*
Authors: Devor Renee L. , Kang Paul , Wellnitz Chasity , Nigro John J. , Velez Daniel A. , Willis Brigham C.
Published: January 2018

Objectives:

1) Determine the correlation between pulmonary dead space fraction and extubation success in postoperative pediatric cardiac patients; and 2) document the natural history of pulmonary dead space fractions, dynamic compliance, and airway resistance during the first 72 hours postoperatively in postoperative pediatric cardiac patients.

Design:

A retrospective chart review.

Setting:

Cardiac ICU in a quaternary care free-standing children’s hospital.

Patients:

Twenty-nine with balanced single ventricle physiology, 61 with two ventricle physiology.

Interventions:

None.

Measurements and Main Results:

We collected data for all pediatric patients undergoing congenital cardiac surgery over a 14-month period during the first 72 hours postoperatively as well as prior to extubation. Overall, patients with successful extubations had lower preextubation dead space fractions and shorter lengths of stay. Single ventricle patients had higher initial postoperative and preextubation dead space fractions. Two-ventricle physiology patients had higher extubation failure rates if the preextubation dead space fraction was greater than 0.5, whereas single ventricle patients had similar extubation failure rates whether preextubation dead space fractions were less than or equal to 0.5 or greater than 0.5. Additionally, increasing initial dead space fraction values predicted prolonged mechanical ventilation times. Airway resistance and dynamic compliance were similar between those with successful extubations and those who failed.

Conclusions:

Initial postoperative dead space fraction correlates with the length of mechanical ventilation in two ventricle patients but not in single ventricle patients. Lower preextubation dead space fractions are a strong predictor of successful extubation in two ventricle patients after cardiac surgery, but may not be as useful in single ventricle patients.
Rapid Response: To Scan or Not to Scan? The Utility of Noncontrast CT Head for Altered Mental Status
Authors: Thacker Purujit J. , Sethi Mansha , Sternlieb Jonathan , Schneider Doron , Naglak Mary , Patel Rajeshkumar R.
Published: January 2018

Objectives

The aims of the study were the following: (1) to determine how often computed tomography (CT) scans of the head are obtained on rapid responses called for altered mental status (AMS), (2) to determine whether CT imaging of the head is required during all rapid responses called for AMS, (3) to determine which patients would benefit from CT scans of the head in this setting, (4) to note whether an adequate neurologic exam was documented, (5) to determine the cost of CT scans that did not change management, and (6) to examine the role of medications leading to AMS.

Methods

The study was a retrospective chart review at Abington Jefferson Hospital. Data collected included the age, sex, time of rapid response, clinical condition of the patient, whether an arterial blood gas and blood glucose were done, and whether a neurological exam was documented in the resident’s rapid response team note. The patien’s medications were also reviewed. Computed tomography scan findings as well as changes made in a patient’s care as a result of the scan were recorded. Any findings that did not lead to a change in management were considered a “negative” scan.

Results

Overall, 610 rapid responses were activated from January to August 2016. One hundred four (17.04%) of the total rapid responses were for AMS and 83 (79.8%) of these patients underwent noncontrast CT scan of the head. The mean (SD) age of the patients was 74.7 (13.6) years. A total of 56.6% were female. The most frequent clinical conditions documented at the time of rapid responses were noted as confused (33.7%, 28/83), either lethargic or unconscious (32.5%, 27/83), and concern for stroke (21.7%, 18/83). A total of 96.4% (80/83) of the CT scans done were negative for any acute changes. The three patients with positive scans (3/83) had a change in management as a result of the scans. If patients with symptoms concerning for stroke and unconscious patients are excluded, the total number of remaining patients is 56. Of these, zero patients had a positive scan. A total of 64.7% of the rapid response teams were activated either in the afternoon (31.3%) or at night (33.7%). A total of 33.7% had a complete neurological exam documented. A total of 66.2% were either incomplete (34.9%) or absent (31.3%). Sixty percent of the patients who had a CT head for AMS also had a blood sugar checked at bedside. Thirty-eight percent had an arterial blood gas. More than half the patients were taking one or more sedating medications (45/83, 57.8%). Most patients were not on anticoagulants (79.5%).

Conclusions

The findings of this study suggest that CT scan of the head is useful in older patients, patients with symptoms concerning for stroke, or cases of sudden onset of impaired consciousness. Noncontrast CT scans of the head are not useful for other presentations of AMS.
Mini- or Less-open Sublay Operation (MILOS): A New Minimally Invasive Technique for the Extraperitoneal Mesh Repair of Incisional Hernias
Authors: Reinpold Wolfgang , Schröder Michael , Berger Cigdem , Nehls Jennifer , Schröder Alexander , Hukauf Martin , Köckerling Ferdinand , Bittner Reinhard
Published: January 2018

Objective:

Improvement of ventral hernia repair.

Background:

Despite the use of mesh and other recent improvements, the currently popular techniques of ventral hernia repair have specific disadvantages and risks.

Methods:

We developed the endoscopically assisted mini- or less-open sublay (MILOS) concept. The operation is performed transhernially via a small incision with light-holding laparoscopic instruments either under direct, or endoscopic visualization. An endoscopic light tube was developed to facilitate this approach (EndotorchTM Wolf Company). Each MILOS operation can be converted to standard total extraperitoneal gas endoscopy once an extraperitoneal space of at least 8 cm has been created. All MILOS operations were prospectively documented in the German Hernia registry with 1 year questionnaire follow-up. Propensity score matching of incisional hernia operations comparing the results of the MILOS operation with the laparoscopic intraperitoneal onlay mesh operation (IPOM) and open sublay repair from other German Hernia registry institutions was performed.

Results:

Six hundred fifteen MILOS incisional hernia operations were included. Compared with laparoscopic IPOM incisional hernia operation, the MILOS repair is associated with significantly a fewer postoperative surgical complications (P < 0.001) general complications (P < 0.004), recurrences (P < 0.001), and less chronic pain (P < 0.001). Matched pair analysis with open sublay repair revealed significantly a fewer postoperative complications (P < 0.001), reoperations (P < 0.001), infections (P = 0.007), general complications (P < 0.001), recurrences (P = 0.017), and less chronic pain (P < 0.001).

Conclusions:

The MILOS technique allows minimally invasive transhernial repair of incisional hernias using large retromuscular/preperitoneal meshes with low morbidity. The technique combines the advantages of open sublay and the laparoscopic IPOM repair.

ClinicalTrials.gov Identifier NCT03133000
Retinal Arterio-Arterial Collaterals in Susac Syndrome
Authors: Egan Robert A. , Jirawuthiworavong Guy , Lincoff Norah S. , Chen John J. , Francis Courtney E. , Leavitt Jacqueline A.
Published: January 2018

Background:

The ophthalmic findings of Susac syndrome (SS) consist of visual field defects related to branch retinal artery occlusion (BRAO), and fluorescein angiography (FA) reveals a unique staining pattern. To date, retinal arterial collateral development has been described only in a single patient. Given that the immunopathological process in SS induces retinal ischemia, it is conceivable that abnormal blood vessel development may occur in affected individuals.

Methods:

This is a retrospective observational study. The medical records including fundus photography and FA of all patients with SS were reviewed, and those with any type of retinal arterial collateral were identified.

Results:

A total of 11 patients were identified with retinal collaterals. Five were men. Age ranged from 20 to 50 years. Ten patients had arterio-arterial (A-A) collaterals and 1 had arterio-venous (A-V) collaterals, and all had collaterals remote from the optic disc. No collaterals were present at onset of illness and the first developed at 9 months.

Conclusions:

The literature reveals scant evidence for the association between BRAO and retinal arterial collaterals. Our findings indicate that retinal arterial collaterals in SS are usually A-A and not A-V and may be more common in this disorder than previously believed. Collaterals do not develop early in the disease, and there may be a predilection toward development in men. The chronic inflammatory state of SS may be the stimulus for the development of these arterial collaterals.
Geographical range size and latitude predict population genetic structure in a global survey
Authors: Pelletier Tara A. , Carstens Bryan C.
Published: January 2018

While genetic diversity within species is influenced by both geographical distance and environmental gradients, it is unclear what other factors are likely to promote population genetic structure. Using a machine learning framework and georeferenced DNA sequences from more than 8000 species, we demonstrate that geographical attributes of the species range, including total size, latitude and elevation, are the most important predictors of which species are likely to contain structured genetic variation. While latitude is well known as an important predictor of biodiversity, our work suggests that it also plays a key role in shaping diversity within species.
Keeping the home fires burning: AMP-activated protein kinase
Authors: Hardie D. Grahame
Published: January 2018

Living cells obtain energy either by oxidizing reduced compounds of organic or mineral origin or by absorbing light. Whichever energy source is used, some of the energy released is conserved by converting adenosine diphosphate (ADP) to adenosine triphosphate (ATP), which are analogous to the chemicals in a rechargeable battery. The energy released by the conversion of ATP back to ADP is used to drive most energy-requiring processes, including cell growth, cell division, communication and movement. It is clearly essential to life that the production and consumption of ATP are always maintained in balance, and the AMP-activated protein kinase (AMPK) is one of the key cellular regulatory systems that ensures this. In eukaryotic cells (cells with nuclei and other internal membrane-bound structures, including human cells), most ATP is produced in mitochondria, which are thought to have been derived by the engulfment of oxidative bacteria by a host cell not previously able to use molecular oxygen. AMPK is activated by increasing AMP or ADP (AMP being generated from ADP whenever ADP rises) coupled with falling ATP. Relatives of AMPK are found in essentially all eukaryotes, and it may have evolved to allow the host cell to monitor the output of the newly acquired mitochondria and step their ATP production up or down according to the demand. Structural studies have illuminated how AMPK achieves the task of detecting small changes in AMP and ADP, despite the presence of much higher concentrations of ATP. Recently, it has been shown that AMPK can also sense the availability of glucose, the primary carbon source for most eukaryotic cells, via a mechanism independent of changes in AMP or ADP. Once activated by energy imbalance or glucose lack, AMPK modifies many target proteins by transferring phosphate groups to them from ATP. By this means, numerous ATP-producing processes are switched on (including the production of new mitochondria) and ATP-consuming processes are switched off, thus restoring energy homeostasis. Drugs that modulate AMPK have great potential in the treatment of metabolic disorders such as obesity and Type 2 diabetes, and even cancer. Indeed, some existing drugs such as metformin and aspirin, which were derived from traditional herbal remedies, appear to work, in part, by activating AMPK.
Emergence and dynamics of self-producing information niches as a step towards pre-evolutionary organization
Authors: Carter Richard J. , Wiesner Karoline , Mann Stephen
Published: January 2018

As a step towards understanding pre-evolutionary organization in non-genetic systems, we develop a model to investigate the emergence and dynamics of proto-autopoietic networks in an interacting population of simple information processing entities (automata). Our simulations indicate that dynamically stable strongly connected networks of mutually producing communication channels emerge under specific environmental conditions. We refer to these distinct organizational steady states as
information niches
. In each case, we measure the information content by the Shannon entropy, and determine the fitness landscape, robustness and transition pathways for information niches subjected to intermittent environmental perturbations under non-evolutionary conditions. By determining the information required to generate each niche, we show that niche transitions are only allowed if accompanied by an equal or increased level of information production that arises internally or via environmental perturbations that serve as an exogenous source of population diversification. Overall, our simulations show how proto-autopoietic networks of basic information processors form and compete, and under what conditions they persist over time or go extinct. These findings may be relevant to understanding how inanimate systems such as chemically communicating protocells can initiate the transition to living matter prior to the onset of contemporary evolutionary and genetic mechanisms.
Experiencing El Niño conditions during early life reduces recruiting probabilities but not adult survival
Authors: Ancona Sergio , Zúñiga-Vega J. Jaime , Rodríguez Cristina , Drummond Hugh
Published: January 2018

In wild long-lived animals, analysis of impacts of stressful natal conditions on adult performance has rarely embraced the entire age span, and the possibility that costs are expressed late in life has seldom been examined. Using 26 years of data from 8541 fledglings and 1310 adults of the blue-footed booby (
Sula nebouxii
), a marine bird that can live up to 23 years, we tested whether experiencing the warm waters and food scarcity associated with El Niño in the natal year reduces recruitment or survival over the adult lifetime. Warm water in the natal year reduced the probability of recruiting; each additional degree (°C) of water temperature meant a reduction of roughly 50% in fledglings' probability of returning to the natal colony as breeders. Warm water in the current year impacted adult survival, with greater effect at the oldest ages than during early adulthood. However, warm water in the natal year did not affect survival at any age over the adult lifespan. A previous study showed that early recruitment and widely spaced breeding allow boobies that experience warm waters in the natal year to achieve normal fledgling production over the first 10 years; our results now show that this reproductive effort incurs no survival penalty, not even late in life. This pattern is additional evidence of buffering against stressful natal conditions via life-history adjustments.
In situ
formation of surface-functionalized ionic calcium carbonate nanoparticles with liquid-like behaviours and their electrical properties
Authors: Wang Xiangshuo , Shi Ling , Zhang Junying , Cheng Jue , Wang Xiaodong
Published: January 2018

This paper reports a new route to synthesize calcium carbonate (CaCO
3
)-based nanoscale ionic materials (NIMs) via an
in situ
formation method to form the CaCO
3
nanoparticles with a polysiloxane quaternary ammonium salt (PQAC) corona (PQAC-CaCO
3
nanoparticles), followed by an ionic exchange reaction to fabricate a poly(ethylene glycol)-tailed sulfonate anion (NPEP) canopy. The chemical compositions and structures of the CaCO
3
-based NIMs synthesized in this work were confirmed by Fourier-transform infrared spectroscopy and solid-state
13
C NMR spectroscopy. Transmission electron microscopic observation indicated that the CaCO
3
-based NIMs presented a rhombohedral shape with a well-defined core-shell structure, and they also obtained an NPEP canopy with a thickness of 4–6 nm. X-ray powder diffraction investigation confirmed that the CaCO
3
inner core had a calcite crystalline structure, whereas the NPEP canopy was amorphous. The NPEP canopy was found to show a characteristic crystallization–melting behaviour in the presence of the ion bonding with PQAC-CaCO
3
nanoparticles according to the characterization of differential scanning calorimetry. Thermogravimetric analysis indicated that the CaCO
3
-based NIMs achieved a high content of NPEP canopy as well as an improvement in thermal stability owing to the ion-bonding effect. Most of all, the CaCO
3
-based NIMs demonstrated a liquid-like behaviour above the critical temperature in the absence of solvent. Moreover, the CaCO
3
-based NIMs also showed a relatively high electrical conductivity with a temperature dependency due to the ionic conductive effect. This work will provide a more feasible and energy-saving methodology for the preparation of CaCO
3
-based NIMs to promote their industrialization and extensive applications.
Signatures of natural selection in abiotic stress-responsive genes ofSolanum chilense
Authors: Böndel Katharina B. , Nosenko Tetyana , Stephan Wolfgang
Published: January 2018

Environmental conditions are strong selective forces, which may influence adaptation and speciation. The wild tomato speciesSolanum chilense, native to South America, is exposed to a range of abiotic stress factors. To identify signatures of natural selection and local adaptation, we analysed 16 genes involved in the abiotic stress response and compared the results to a set of reference genes in 23 populations across the entire species range. The abiotic stress-responsive genes are characterized by elevated nonsynonymous nucleotide diversity and divergence. We detected signatures of positive selection in several abiotic stress-responsive genes on both the population and species levels. Local adaptation to abiotic stresses is particularly apparent at the boundary of the species distribution in populations from coastal low-altitude and mountainous high-altitude regions.
Field energetics and lung function in wild bottlenose dolphins,Tursiops truncatus, in Sarasota Bay Florida
Authors: Fahlman A. , Brodsky M. , Wells R. , McHugh K. , Allen J. , Barleycorn A. , Sweeney J. C. , Fauquier D. , Moore M.
Published: January 2018

We measured respiratory flow rates, and expired O2in 32 (2–34 years, body mass [Mb] range: 73–291 kg) common bottlenose dolphins (Tursiops truncatus) during voluntary breaths on land or in water (between 2014 and 2017). The data were used to measure the resting O2consumption rate (V˙O2, range: 0.76–9.45 ml O2 min−1 kg−1) and tidal volume (VT, range: 2.2–10.4 l) during rest. For adult dolphins, the restingVT, but notV˙O2, correlated with body mass (Mb, range: 141–291 kg) with an allometric mass-exponent of 0.41. These data suggest that the mass-specificVTof larger dolphins decreases considerably more than that of terrestrial mammals (mass-exponent: 1.03). The average restingsV˙O2was similar to previously published metabolic measurements from the same species. Our data indicate that the resting metabolic rate for a 150 kg dolphin would be 3.9 ml O2 min−1 kg−1, and the metabolic rate for active animals, assuming a multiplier of 3–6, would range from 11.7 to 23.4 ml O2 min−1 kg−1.\absbreak Our measurements provide novel data for resting energy use and respiratory physiology in wild cetaceans, which may have significant value for conservation efforts and for understanding the bioenergetic requirements of this species.
Structure of semiconducting versus fast-ion conducting glasses in the Ag–Ge–Se system
Authors: Zeidler Anita , Salmon Philip S. , Whittaker Dean A. J. , Piarristeguy Andrea , Pradel Annie , Fischer Henry E. , Benmore Chris J. , Gulbiten Ozgur
Published: January 2018

The transition from a semiconductor to a fast-ion conductor with increasing silver content along the Ag

x

(Ge
0.25
Se
0.75
)

(100−
x
)

tie line (0≤
x
≤25) was investigated on multiple length scales by employing a combination of electric force microscopy, X-ray diffraction, and neutron diffraction. The microscopy results show separation into silver-rich and silver-poor phases, where the Ag-rich phase percolates at the onset of fast-ion conductivity. The method of neutron diffraction with Ag isotope substitution was applied to the
x
=5 and
x
=25 compositions, and the results indicate an evolution in structure of the Ag-rich phase with change of composition. The Ag–Se nearest-neighbours are distributed about a distance of 2.64(1) Å, and the Ag–Se coordination number increases from 2.6(3) at
x
=5 to 3.3(2) at
x
=25. For
x
=25, the measured Ag–Ag partial pair-distribution function gives 1.9(2) Ag–Ag nearest-neighbours at a distance of 3.02(2) Å. The results show breakage of Se–Se homopolar bonds as silver is added to the Ge
0.25
Se
0.75
base glass, and the limit of glass-formation at
x
≃28 coincides with an elimination of these bonds. A model is proposed for tracking the breakage of Se–Se homopolar bonds as silver is added to the base glass.
Using sensitivity analysis to identify key factors for the propagation of a plant epidemic
Authors: Rimbaud Loup , Bruchou Claude , Dallot Sylvie , Pleydell David R. J. , Jacquot Emmanuel , Soubeyrand Samuel , Thébaud Gaël
Published: January 2018

Identifying the key factors underlying the spread of a disease is an essential but challenging prerequisite to design management strategies. To tackle this issue, we propose an approach based on sensitivity analyses of a spatiotemporal stochastic model simulating the spread of a plant epidemic. This work is motivated by the spread of sharka, caused by
plum pox virus
, in a real landscape. We first carried out a broad-range sensitivity analysis, ignoring any prior information on six epidemiological parameters, to assess their intrinsic influence on model behaviour. A second analysis benefited from the available knowledge on sharka epidemiology and was thus restricted to more realistic values. The broad-range analysis revealed that the mean duration of the latent period is the most influential parameter of the model, whereas the sharka-specific analysis uncovered the strong impact of the connectivity of the first infected orchard. In addition to demonstrating the interest of sensitivity analyses for a stochastic model, this study highlights the impact of variation ranges of target parameters on the outcome of a sensitivity analysis. With regard to sharka management, our results suggest that sharka surveillance may benefit from paying closer attention to highly connected patches whose infection could trigger serious epidemics.
Specialized specialists and the narrow niche fallacy: a tale of scale-feeding fishes
Authors: Kolmann Matthew A. , Huie Jonathan M. , Evans Kory , Summers Adam P.
Published: January 2018

Although rare within the context of 30 000 species of extant fishes, scale-feeding as an ecological strategy has evolved repeatedly across the teleost tree of life. Scale-feeding (lepidophagous) fishes are diverse in terms of their ecology, behaviour, and specialized morphologies for grazing on scales and mucus of sympatric species. Despite this diversity, the underlying ontogenetic changes in functional and biomechanical properties of associated feeding morphologies in lepidophagous fishes are less understood. We examined the ontogeny of feeding mechanics in two evolutionary lineages of scale-feeding fishes:
Roeboides
, a characin, and
Catoprion
, a piranha. We compare these two scale-feeding taxa with their nearest, non-lepidophagous taxa to identify traits held in common among scale-feeding fishes. We use a combination of micro-computed tomography scanning and iodine staining to measure biomechanical predictors of feeding behaviour such as tooth shape, jaw lever mechanics and jaw musculature. We recover a stark contrast between the feeding morphology of scale-feeding and non-scale-feeding taxa, with lepidophagous fishes displaying some paedomorphic characters through to adulthood. Few traits are shared between lepidophagous characins and piranhas, except for their highly-modified, stout dentition. Given such variability in development, morphology and behaviour, ecological diversity within lepidophagous fishes has been underestimated.
A nanoscale perspective on the effects of transverse microprestress on drying creep of nanoporous solids
Authors: Sinko Robert , Bažant Zdeněk P. , Keten Sinan
Published: January 2018

The Pickett effect describes the excess non-additive strain developed during drying of a nanoporous solid material under creep. One explanation for its origins, developed using micromechanical models, is the progressive relaxation of internally developed microprestress. However, these models have not explicitly considered the effects of this microprestress on nanoscale energy barriers that govern the relative motion and displacement between nanopore walls during deformation. Here, we evaluate the nanoscale effects of transverse microprestresses on the drying creep behaviour of a nanoscale slit pore using coarse-grained molecular dynamics. We find that the underlying energy barrier depends exponentially on the transverse microprestress, which is attributed to changes in the effective viscosity and degree of nanoconfinement of molecules in the water interlayer. Specifically, as the transverse microprestress is relaxed (i.e. its magnitude decreases), the activation energy barrier is reduced, thereby leading to an acceleration of the creep behaviour and a stronger Pickett effect. Based on our simulation results, we introduce a new microprestress-dependent energy term into our existing Arrhenius model, which describes the relative displacement of pore walls as a function of the underlying activation energy barriers. Our findings further verify the existing micromechanical theories for the origin of the Pickett effect and establish a quantitative relationship between the transverse microprestress and the intensity of the Pickett effect.
Evidence for dispersal syndromes in freshwater fishes
Authors: Comte Lise , Olden Julian D.
Published: January 2018

Dispersal is a fundamental process defining the distribution of organisms and has long been a topic of inquiry in ecology and evolution. Emerging research points to an interdependency of dispersal with a diverse suite of traits in terrestrial organisms, however the extent to which such dispersal syndromes exist in freshwater species remains uncertain. Here, we test whether dispersal in freshwater fishes (1) is a fixed property of species, and (2) correlates with life-history, morphological, ecological and behavioural traits, using a global dataset of dispersal distances collected from the literature encompassing 116 riverine species and 196 locations. Our meta-analysis revealed a high degree of repeatability and heritability in the dispersal estimates and strong associations with traits related to life-history strategies, energy allocation to reproduction, ecological specialization and swimming skills. Together, these results demonstrate that similar to terrestrial organisms, the multi-dimensional nature of dispersal syndromes in freshwater species offer opportunities for the development of a unifying paradigm of movement ecology that transcend taxonomic and biogeographical realms. The high explanatory power of the models also suggests that trait-based and phylogenetic approaches hold considerable promises to inform conservation efforts in a rapidly changing world.
The evolution of sexual signal modes and associated sensor morphology in fireflies (Lampyridae, Coleoptera)
Authors: Stanger-Hall Kathrin F. , Sander Lower Sarah E. , Lindberg Lauri , Hopkins Andrew , Pallansch Jenna , Hall David W.
Published: January 2018

Animals employ different sexual signal modes (e.g. visual, acoustic, chemical) in different environments and behavioural contexts. If sensory structures are costly, then evolutionary shifts in primary signal mode should be associated with changes in sensor morphology. Further, sex differences are expected if male and female signalling behaviours differ. Fireflies are known for their light displays, but many species communicate exclusively with pheromones, including species that recently lost their light signals. We performed phylogenetically controlled analyses of male eye and antenna size in 46 North American taxa, and found that light signals are associated with larger eyes and shorter antennae. In addition, following a transition from nocturnal light displays to diurnal pheromones, eye size reductions occur more rapidly than antenna size increases. In agreement with the North American taxa, across 101 worldwide firefly taxa in 32 genera, we found light displays are associated with larger eye and smaller antenna sizes in both males and females. For those taxa with both male and female data, we found sex differences in eye size and, for diurnal species, in antenna size.
Bayesian inference reveals positive but subtle effects of experimental fishery closures on marine predator demographics
Authors: Sherley Richard B. , Barham Barbara J. , Barham Peter J. , Campbell Kate J. , Crawford Robert J. M. , Grigg Jennifer , Horswill Cat , McInnes Alistair , Morris Taryn L. , Pichegru Lorien , Steinfurth Antje , Weller Florian , Winker Henning , Votier Stephen C.
Published: January 2018

Global forage-fish landings are increasing, with potentially grave consequences for marine ecosystems. Predators of forage fish may be influenced by this harvest, but the nature of these effects is contentious. Experimental fishery manipulations offer the best solution to quantify population-level impacts, but are rare. We used Bayesian inference to examine changes in chick survival, body condition and population growth rate of endangered African penguins
Spheniscus demersus
in response to 8 years of alternating time–area closures around two pairs of colonies. Our results demonstrate that fishing closures improved chick survival and condition, after controlling for changing prey availability. However, this effect was inconsistent across sites and years, highlighting the difficultly of assessing management interventions in marine ecosystems. Nevertheless, modelled increases in population growth rates exceeded 1% at one colony; i.e. the threshold considered biologically meaningful by fisheries management in South Africa. Fishing closures evidently can improve the population trend of a forage-fish-dependent predator—we therefore recommend they continue in South Africa and support their application elsewhere. However, detecting demographic gains for mobile marine predators from small no-take zones requires experimental time frames and scales that will often exceed those desired by decision makers.
Mutual assessment during ritualized fighting in mantis shrimp (Stomatopoda)
Authors: Green P. A. , Patek S. N.
Published: January 2018

Safe and effective conflict resolution is critical for survival and reproduction. Theoretical models describe how animals resolve conflict by assessing their own and/or their opponent's ability (resource holding potential, RHP), yet experimental tests of these models are often inconclusive. Recent reviews have suggested this uncertainty could be alleviated by using multiple approaches to test assessment models. The mantis shrimp
Neogonodactylus bredini
presents visual displays and ritualistically exchanges high-force strikes during territorial contests. We tested how
N. bredini
contest dynamics were explained by any of three assessment models—pure self-assessment, cumulative assessment and mutual assessment—using correlations and a novel, network analysis-based sequential behavioural analysis. We staged dyadic contests over burrow access between competitors matched either randomly or based on body size. In both randomly and size-matched contests, the best metric of RHP was body mass. Burrow residency interacted with mass to predict outcome. Correlations between contest costs and RHP rejected pure self-assessment, but could not fully differentiate between cumulative and mutual assessment. The sequential behavioural analysis ruled out cumulative assessment and supported mutual assessment. Our results demonstrate how multiple analyses provide strong inference to tests of assessment models and illuminate how individual behaviours constitute an assessment strategy.
Experimental heatwaves negatively impact sperm quality in the zebra finch
Authors: Hurley Laura L. , McDiarmid Callum S. , Friesen Christopher R. , Griffith Simon C. , Rowe Melissah
Published: January 2018

For sexually reproducing species, functionally competent sperm are critical to reproduction. While high atmospheric temperatures are known to influence the timing of breeding, incubation and reproductive success in birds, the effect of temperature on sperm quality remains largely unexplored. Here, we experimentally investigated the impact of ecologically relevant extreme temperatures on cloacal temperature and sperm morphology and motility in zebra finchesTaeniopygia guttata. We periodically sampled males exposed to 30°C or 40°C temperatures daily for 14 consecutive days. Following a 12-day (23°C) recovery period, birds were again exposed to heat, but under the alternate treatment (e.g. birds initially exposed to 40°C were exposed to 30°C). Elevated temperatures led to an increase in cloacal temperature and a reduction in the proportion of sperm with normal morphology; these effects were most notable under 40°C conditions, and were influenced by the duration of heat exposure and prior exposure to high temperature. Our findings highlight the potential role of temperature in determining male fertility in birds, and perhaps also in constraining the timing of avian breeding. Given the increased frequency of heatwaves in a warming world, our results suggest the need for further work on climatic influences on sperm quality and male fertility.
Single-cell transcriptome analysis reveals estrogen signaling augments the mitochondrial folate pathway to coordinately fuel purine and polyamine synthesis in breast cancer cells
Authors: Zhu Detu , Zhaozu Xianglan , Cui Guimei , Chang Shiehong , See Yi Xiang , Lim Michelle Gek Liang , Guo Dajiang , Chen Xin , Robson Paul , Luo Yumei , Cheung Edwin
Published: January 2018

Estrogen regulates diverse physiological effects and drives breast tumor progression by directly activating estrogen receptor α (ERα). However, due to the stochastic nature of gene transcription and the resulting heterogeneous cellular response, it is important to investigate estrogen-stimulated gene expression profiles at the single-cell level in order to fully understand how ERα regulates transcription in breast cancer cells. In this study, we performed single-cell transcriptome analysis on ERα-positive breast cancer cell lines following 17β-estradiol stimulation. Overall, we observed robust gene expression diversity between individual cells. Moreover, we found over two thirds of the genes in breast cancer cells displayed a bimodal expression pattern, which caused averaging artifacts and masked the identification of potential estrogen-regulated genes. We overcame this issue by reconstructing a dynamic estrogen-responsive transcriptional network from discrete time points into a pseudotemporal continuum. Pathway analysis of the differentially expressed genes derived from the pseudotemporal analysis showed an estrogen-stimulated metabolic switch that favored biosynthesis and cell proliferation but reduced estrogen degradation. In addition, we identified folate-mediated one-carbon metabolism as a novel estrogen-regulated pathway in breast cancer cells. Notably, estrogen stimulation reprogramed this pathway through the mitochondrial folate pathway to coordinately fuel polyamine and de novo purine synthesis. Finally, we showed AZIN1 and PPAT, key regulators in the above pathways, are direct ERα target genes and essential for breast cancer cell survival and growth. In summary, our single-cell study illustrated a dynamic transcriptional heterogeneity in ERα-positive breast cancer cells in response to estrogen stimulation and uncovered a novel mechanism of an estrogen-mediated metabolic switch.
The Viral Protein Corona Directs Viral Pathogenesis and Amyloid Aggregation
Authors: Ezzat Kariem , Pernemalm Maria , Pålsson Sandra , Roberts Thomas C. , Järver Peter , Dondalska Aleksandra , Bestas Burcu , Sobkowiak Michal J. , Levänen Bettina , Sköld Magnus , Thompson Elizabeth A. , Saher Osama , Kari Otto K. , Lajunen Tatu , Ekström Eva Sverremark , Nilsson Caroline , Ishchenko Yevheniia , Malm Tarja , Wood Matthew J.A. , Power Ultan F. , Masich Sergej , Lindén Anders , Sandberg Johan K. , Lehtiö Janne , Spetz Anna-Lena , Andaloussi Samir EL
Published: January 2018

Artificial nanoparticles accumulate a protein corona layer in biological fluids, which significantly influences their bioactivity. As nanosized obligate intracellular parasites, viruses share many biophysical properties with artificial nanoparticles in extracellular environments and here we show that respiratory syncytial virus (RSV) and herpes simplex virus 1 (HSV-1) accumulate a rich and distinctive protein corona in different biological fluids. Moreover, we show that corona pre-coating differentially affects viral infectivity and immune cell activation. Additionally, we demonstrate that viruses bind amyloidogenic peptides in their corona and catalyze amyloid formation via surface-assisted heterogeneous nucleation. Importantly, we show that HSV-1 catalyzes the aggregation of the amyloid beta peptide (Aβ42), a major constituent of amyloid plaques in Alzheimer’s disease, in-vitro and in animal models. Our results highlight the viral protein corona as an acquired structural layer that is critical for viral-host interactions and illustrate a mechanistic convergence between viral and amyloid pathologies.
Using Network Analysis to Localize the Epileptogenic Zone from Invasive EEG Recordings in Intractable Focal Epilepsy
Authors: Li Adam , Chennuri Bhaskar , Subramanian Sandya , Yaffe Robert , Gliske Steve , Stacey William , Norton Robert , Jordan Austin , Zaghloul Kareem A. , Inati Sara K. , Agrawal Shubhi , Haagensen Jennifer J. , Hopp Jennifer , Atallah Chalita , Johnson Emily , Crone Nathan , Anderson William S. , Fitzgerald Zach , Bulacio Juan , Gale John T. , Sarma Sridevi V. , Gonzalez-Martinez Jorge
Published: January 2018

Treatment of medically intractable focal epilepsy (MIFE) by surgical resection of the epileptogenic zone (EZ) is often effective provided the EZ can be reliably identified. Even with the use of invasive recordings, the clinical differentiation between the EZ and normal brain areas can be quite challenging, mainly in patients without MRI detectable lesions. Consequently, despite relatively large brain regions being removed, surgical success rates barely reach 60-65%. Such variable and unfavorable outcomes associated with high morbidity rates are often caused by imprecise and/or inaccurate EZ localization. We developed a localization algorithm that uses network-based data analytics to process invasive EEG recordings. This network algorithm analyzes the centrality signatures of every contact electrode within the recording network and characterizes contacts into susceptible EZ based on the centrality trends over time. The algorithm was tested in a retrospective study that included 42 patients from four epilepsy centers. Our algorithm had higher agreement with EZ regions identified by clinicians for patients with successful surgical outcomes and less agreement for patients with failed outcomes. These findings suggest that network analytics and a network systems perspective of epilepsy may be useful in assisting clinicians in more accurately localizing the EZ.

AUTHOR SUMMARY

Epilepsy is a disease that results in abnormal firing patterns in parts of the brain that comprise the epileptogenic network, known as the epileptogenic zone (EZ). Current methods to localize the EZ for surgical treatment often requires observations of hundreds of thousands of EEG data points measured from many electrodes implanted in a patient’s brain. In this paper, we used network science to show that EZ regions may exhibit specific network signatures before, during and after seizure events. Our algorithm computes the likelihood of each electrode being in the EZ and tends to agree more with clinicians during successful resections and less during failed surgeries. These results suggest that a networked analysis approach to EZ localization may be valuable in a clinical setting.