bluuebunny/crossref_metadata_2025 huggingface dataset:
A DFT-based theoretical model for the calculation of spectral profiles of lanthanide M4,5-edge x-ray absorption
Authors: Ramanantoanina Harry
Published: August 2018

This presentation reports the theoretical study of 3d core-electron excitation in lanthanide compounds in terms of electronic structure effects and optical properties. The calculations are done at the Density-Functional Theory (DFT) level complemented with an effective Hamiltonian based on ligand-field theory. The strategy consists of obtaining from DFT a totally symmetric density, where an active subspace is set up that forms the basis of the fivefold 3d and sevenfold 4f atomic orbitals of the lanthanide ion. This active subspace is defined with the fractional occupation of electrons, which represents open-shell species with the composite configuration 3d94fn+1. Based on the ligand-field analysis of the DFT results, the multiplet energies and ligand-field effects associated with the configuration 3d94fn+1 are evaluated; and the X-ray absorption spectra are simulated in terms of the intra-atomic 4fn → 3d94fn+1 electron transitions within the electric-dipole approximation. Examples for application are proposed taking into consideration the isolated trivalent lanthanides ions and compounds Cs2NaPrX6, with X = F, Cl, and Br. The results are compared with available experimental data, where a good agreement is qualitatively achieved. Also, the screening of the inter-electron repulsion and spin-orbit coupling interaction is numerically obtained that allows one to establish a fully non-empirical treatment of the 3d core-electron excitation, which can be valuable in the characterization and modeling of the spectral profiles of lanthanide M4,5-edge X-ray absorption spectroscopy. The enclosed theoretical model, which is being implemented in the Amsterdam Density Functional (ADF) suite of programs, is computationally economic and can be applied to any lanthanide system without limitations in terms of the size of the matrix elements of the effective Hamiltonian or the coordination symmetry of the lanthanide center.
The hydrodynamic behavior of a squirmer swimming in power-law fluid
Authors: Ouyang Zhenyu , Lin Jianzhong , Ku Xiaoke
Published: August 2018

The hydrodynamic behavior of a squirmer swimming in the flow of power-law fluid is studied numerically with an immersed boundary-lattice Boltzmann method. The power-law fluids with three typical power-law indexes (n = 0.5, 1, and 1.5) are selected for embodying the characteristics of non-Newtonian fluid. The results show that, at zero Reynolds number, the squirmers swim slower in the shear-thinning fluid (n = 0.5) than in the Newtonian fluid (n = 1). The speed of squirmer swimming increases monotonically with the Reynolds number in the shear-thickening fluid (n = 1.5). When the fluid inertia is taken into account, the speed of a pusher (a kind of swimmer type) increases monotonically with the Reynolds number, while the speed of a puller (another kind of swimmer type) shows a non-monotonic increasing tendency. Some critical points, beyond which the pullers swim with lateral displacement, are obtained. The flow field and force distribution around the squirmer are calculated and analyzed. The power expenditure of squirmers in different kinds of flow is also studied. It is found that, as the Reynolds number increases, the power expenditure generally decreases in shear-thinning fluid, which is different from the case in Newtonian fluid and shear-thickening fluid. Finally, the hydrodynamic efficiency is introduced to compare the power expenditure of squirmers with that of a counterpart particle towing in the same type of fluid. Results show that the hydrodynamic efficiency of pushers increases with the Reynolds number, while the hydrodynamic efficiency of pullers shows non-monotonic behavior when the Reynolds number is varied.
Responses of herbage yield and soil phosphorus fractions to phosphorus fertilisation on a degraded arid steppe
Authors: Wang Dangjun , He Zhibin , Zhang Zhen , Du Qingfeng , Zhang Yong , Hou Xiangyang , Guo Yanjun
Published: August 2018

Low plant-available phosphorus (P) in degraded arid steppes greatly limits plant yields. However, whether exterior P addition will improve the soil P availability and thus increase plant yield in these degraded arid steppes is still not certain. In the current study, a severely degraded arid steppe in Inner Mongolia, China, with soil-available P <5 mg/kg, was fertilised annually with chemical or manure P for two years (2014, dry year; 2015, wet year). There were six fertilisation treatments: 0, 30 kg P/ha, 60 kg P/ha, 90 kg P/ha, 4000 kg sheep manure/ha (equalling 16.4 kg P/ha) and 8000 kg sheep manure/ha (32.8 kg P/ha). A pot experiment with Stipa krylovii (the dominant plant species in the tested steppe) and five P application rates (0, 30, 60, 90 and 120 kg P/ha) was also conducted, under well-watered and nitrogen-fertilised conditions, using surface soils from unfertilised plots in the field. Results indicated that the tested soils had strong P adsorption capacity and weaker desorption capacity, and that the labile P fractions were quickly transformed into less labile fractions, reducing P availabilities. Overall, chemical P fertiliser resulted in the accumulation of Ca10-P and occluded P, whereas sheep manure resulted in the accumulation of moderately resistant organic P and highly resistant organic P. Phosphorus fertilisation was associated with an increase in plant P concentrations in both 2014 and 2015, and a low P rate (30 kg P/ha in the current study) was able to improve the aboveground biomass in both the field experiment in the wet year and the pot experiment under well-watered conditions. Thus, in degraded arid steppes, P fertilisation may be unnecessary in dry years. A low rate of P fertilisation is recommended in wet years to improve soil P status and steppe plant productivity.
In-vitro evaluation of rice and wheat straw biochars’ effect on pyrazosulfuron-ethyl degradation and microbial activity in rice-planted soil
Authors: Manna Suman , Singh Neera , Singh Shashi Bala
Published: August 2018

A pot-culture evaluation of 0.5% wheat (WBC600) and rice straw (RBC600) biochar amendments on degradation of pyrazosulfuron-ethyl (PYRAZO) in rice-planted sandy loam soil was undertaken. Results suggest that PYRAZO and its metabolites persisted for longer in biochar-amended soils and degradation followed biphasic dissipation. Three metabolites of PYRAZO viz. 5-(aminosulfonyl)-1-methyl-1 H-pyrazole-4-carboxylic acid, ethyl 5-(aminosulfonyl)-1-methyl-1 H-pyrazol-4-carboxylate and 2-amino-4,6- dimethoxy pyrimidine (AP) were detected in soil. There was no significant difference in the amounts of metabolites recovered from no-biochar and biochar-amended soils except the metabolite AP, which was less persistent in the biochar-amended soils. The half-life of pyrazosulfuron-ethyl residues (calculated using amount of parent PYRAZO and persistent AP metabolites) during the first and second phase in the no-biochar control, 0.5% WBC600 and 0.5% RBC600 treatments were 4.7 and 9.2, 5.8 and 12.6, and 7.0 and 14.5 days respectively. Biochars did not have any inhibitory effect on the soil microbial biomass, soil dehydrogenase, fluorescein diacetate and acid/alkaline phosphatase activity, but slightly increased microbial biomass carbon content. This study suggests that even at 0.5% dose the rice and wheat biochars had a marginal effect on persistence of PYRAZO residues, thus, agronomic application of these biochars can be suggested.
First principles-based multiscale atomistic methods for input into first principles nonequilibrium transport across interfaces
Authors: Cheng Tao , Jaramillo-Botero Andres , An Qi , Ilyin Daniil V. , Naserifar Saber , Goddard William A.
Published: August 2018

This issue of PNAS features “nonequilibrium transport and mixing across interfaces,” with several papers describing the nonequilibrium coupling of transport at interfaces, including mesoscopic and macroscopic dynamics in fluids, plasma, and other materials over scales from microscale to celestial. Most such descriptions describe the materials in terms of the density and equations of state rather than specific atomic structures and chemical processes. It is at interfacial boundaries where such atomistic information is most relevant. However, there is not yet a practical way to couple these phenomena with the atomistic description of chemistry. The starting point for including such information is the quantum mechanics (QM). However, practical QM calculations are limited to a hundred atoms for dozens of picoseconds, far from the scales required to inform the continuum level with the proper atomistic description. To bridge this enormous gap, we need to develop practical methods to extend the scale of the atomistic simulation by several orders of magnitude while retaining the level of QM accuracy in describing the chemical process. These developments would enable continuum modeling of turbulent transport at interfaces to incorporate the relevant chemistry. In this perspective, we will focus on recent progress in accomplishing these extensions in first principles-based atomistic simulations and the strategies being pursued to increase the accuracy of very large scales while dramatically decreasing the computational effort.
Synergistic O
3
+ OH oxidation pathway to extremely low-volatility dimers revealed in β-pinene secondary organic aerosol
Authors: Kenseth Christopher M. , Huang Yuanlong , Zhao Ran , Dalleska Nathan F. , Hethcox J. Caleb , Stoltz Brian M. , Seinfeld John H.
Published: August 2018

Significance

Secondary organic aerosol (SOA) is ubiquitous in the atmosphere and plays a pivotal role in climate, air quality, and health. Monoterpenes, emitted in large quantities from forested regions, are a dominant source of SOA globally, with dimers having been identified as key contributors to particle formation and growth. Here, we establish the role of concerted oxidation by O
3
and OH as a significant route to dimer formation in SOA generated from β-pinene, the second-most-abundant monoterpene emitted to the atmosphere. Production of this class of dimers is found to occur through both gas- and particle-phase processes. Dimer formation via synergistic O
3
+ OH oxidation could represent an appreciable source of “missing” SOA not included in current atmospheric models.
Selective Na
V
1.1 activation rescues Dravet syndrome mice from seizures and premature death
Authors: Richards Kay L. , Milligan Carol J. , Richardson Robert J. , Jancovski Nikola , Grunnet Morten , Jacobson Laura H. , Undheim Eivind A. B. , Mobli Mehdi , Chow Chun Yuen , Herzig Volker , Csoti Agota , Panyi Gyorgy , Reid Christopher A. , King Glenn F. , Petrou Steven
Published: August 2018

Significance

Spider venom is a rich source of peptides, many targeting ion channels. We assessed a venom peptide, Hm1a, as a potential targeted therapy for Dravet syndrome, the genetic epilepsy linked to a mutation in the gene encoding the sodium channel alpha subunit Na
V
1.1. Cell-based assays showed Hm1a was selective for hNa
V
1.1 over other sodium and potassium channels. Utilizing a mouse model of Dravet syndrome, Hm1a restored inhibitory neuron function and significantly reduced seizures and mortality in heterozygote mice. Evidence from the structure of Hm1a and modeling suggest Hm1a interacts with Na
V
1.1 inactivation domains, providing a structural correlate of the functional mechanisms. This proof-of-concept study provides a promising strategy for future drug development in genetic epilepsy and other neurogenetic disorders.
Computational analysis and prediction of lysine malonylation sites by exploiting informative features in an integrative machine-learning framework
Authors: Zhang Yanju , Xie Ruopeng , Wang Jiawei , Leier André , Marquez-Lago Tatiana T , Akutsu Tatsuya , Webb Geoffrey I , Chou Kuo-Chen , Song Jiangning
Published: August 2018

As a newly discovered post-translational modification (PTM), lysine malonylation (Kmal) regulates a myriad of cellular processes from prokaryotes to eukaryotes and has important implications in human diseases. Despite its functional significance, computational methods to accurately identify malonylation sites are still lacking and urgently needed. In particular, there is currently no comprehensive analysis and assessment of different features and machine learning (ML) methods that are required for constructing the necessary prediction models. Here, we review, analyze and compare 11 different feature encoding methods, with the goal of extracting key patterns and characteristics from residue sequences of Kmal sites. We identify optimized feature sets, with which four commonly used ML methods (random forest, support vector machines, K-nearest neighbor and logistic regression) and one recently proposed [Light Gradient Boosting Machine (LightGBM)] are trained on data from three species, namely, Escherichia coli, Mus musculus and Homo sapiens, and compared using randomized 10-fold cross-validation tests. We show that integration of the single method-based models through ensemble learning further improves the prediction performance and model robustness on the independent test. When compared to the existing state-of-the-art predictor, MaloPred, the optimal ensemble models were more accurate for all three species (AUC: 0.930, 0.923 and 0.944 for E. coli, M. musculus and H. sapiens, respectively). Using the ensemble models, we developed an accessible online predictor, kmal-sp, available at http://kmalsp.erc.monash.edu/. We hope that this comprehensive survey and the proposed strategy for building more accurate models can serve as a useful guide for inspiring future developments of computational methods for PTM site prediction, expedite the discovery of new malonylation and other PTM types and facilitate hypothesis-driven experimental validation of novel malonylated substrates and malonylation sites.
Maturation of the Human Cerebral Cortex During Adolescence: Myelin or Dendritic Arbor?
Authors: Patel Y , Shin J , Gowland P A , Pausova Z , Paus T ,   IMAGEN consortium
Published: August 2018

Previous in vivo studies revealed robust age-related variations in structural properties of the human cerebral cortex during adolescence. Neurobiology underlying these maturational phenomena is largely unknown. Here we employ a virtual-histology approach to gain insights into processes associated with inter-regional variations in cortical microstructure and its maturation, as indexed by magnetization transfer ratio (MTR). Inter-regional variations in MTR correlate with inter-regional variations in expression of genes specific to pyramidal cells (CA1) and ependymal cells; enrichment analyses indicate involvement of these genes in dendritic growth. On the other hand, inter-regional variations in the change of MTR during adolescence correlate with inter-regional profiles of oligodendrocyte-specific gene expression. Complemented by a quantitative hypothetical model of the contribution of surfaces associated with dendritic arbor (1631 m2) and myelin (48 m2), these findings suggest that MTR signals are driven mainly by macromolecules associated with dendritic arbor while maturational changes in the MTR signal are associated with myelination.
Energy Bound for Kapustin–Witten Solutions on S3 × ℝ+
Authors: Leung Naichung Conan , Takahashi Ryosuke
Published: August 2018

We show that for solutions of Kapustin–Witten equation with Nahm pole boundary condition on $S^{3}\times \mathbb{R}^{+}$, there exists a universal constant bound on its Yang–Mills energy $\|F_{A}\|_{L^{2}}$.
Differences in healthcare outcomes between teaching and non teaching hospitals for patients with delirium: a retrospective cohort study
Authors: Kotwal Susrutha , Abougergi Marwan S , Wright Scott
Published: August 2018

Background

The physician workforce at teaching hospitals differs compared to non-teaching hospitals, and data suggest that patient outcomes may also be dissimilar. Delirium is a common, costly disorder among hospitalized patients and approaches to care are not standardized.

Objective

This study set out to explore differences in healthcare outcomes between teaching and non-teaching hospitals for patients admitted with delirium.

Design

Retrospective cohort analysis.

Setting and participants

We used the 2014 Nationwide Inpatient Sample database. Adult patients (≥18 years of age) hospitalized in acute-care hospitals in the USA with delirium (defined with ICD-9 code) were studied.

Main outcome measures

The primary outcome was in-hospital all-cause mortality. Secondary outcomes were discharge status and several measures of healthcare resource utilization: length of stay, total hospitalization costs and multiple procedures performed.

Results

In 2014, out of 57 460 adult patients admitted to hospitals with delirium, 58.4% were hospitalized at teaching hospitals and the remainder 41.6% at non-teaching hospitals. The in-hospital mortality of delirium patients in teaching hospitals was 1.33% (95% CI 1.08%–1.63%), and 1.26% (95% CI 0.97%–1.63%) in non-teaching hospitals. The mean total hospital costs were $7642 (95% CI 7384–7900) in teaching hospitals, and $6650 (95% CI 6460–6840) in non-teaching hospitals. After adjustment for confounders, total hospitalization costs were statistically significantly different between the hospitals types—with non-teaching providing less expensive care.

Conclusions

Patients with delirium admitted to non-teaching hospitals had comparable clinical and process outcomes achieved at lower costs. Further research can be conducted to explore the contextual issues and reasons for these differences in healthcare costs.
Lowered obesity indicator cutoff points more effectively predict 5-year incidence of hypertension in premenopausal women
Authors: Chu Fu-Ling , Jeng Chii
Published: August 2018

Objective

To compare proposed new cutoff points for four obesity indicators—waist-to-height ratio (WHtR), waist circumference (WC), waist-to-hip ratio (WHR) and body mass index (BMI)—with their current cutoff points to determine which are better standards predicting 5-year incidence of hypertension (HT) and diabetes mellitus (DM) among premenopausal women.

Design

Data were obtained from the 2002 and 2007 Survey on the Prevalence of HT, Hyperglycemia and Hyperlipidemia in Taiwan conducted by the Ministry of Health and Welfare, Taiwan. Premenopausal women were grouped based on the proposed cutoff points versus reference cutoff points for obesity indicators.

Participant

A total of 1466 premenopausal women aged between 20 and 57 years old were recruited.

Main outcome measure

Five-year incidence of HT and DM.

Results

Our new obesity indicator cutoff points—WHtR 0.49, WC 74.7 cm, WHR 0.79 and BMI 22.3 kg/m2—were better predictors for 5-year HT incidence in premenopausal women compared with those of current standards, but were not significantly different for DM. Among the four obesity indicators, WHtR and WC were optimal for their 5-year predictive ability for HT and DM in premenopausal women.

Conclusions

To avoid too many cutoff points for practitioners to adopt and memorize, the proposed new cutoff points were recommended preferentially to prevent the incidence of HT and DM in premenopausal women.
Utilization of the Ghana National Health Insurance Scheme and its association with patient perceptions on healthcare quality
Authors: Haw Nel Jason L
Published: August 2018

Objective

To determine the association between the utilization of the Ghana National Health Insurance Scheme (NHIS) and patient perceptions of quality of care.

Methods

Ghana Demographic and Health Survey (GDHS) 2014 had 19 questions on perceptions of quality of care received during the last reported health visit (n = 4332). These questions were summarized into an overall 100-point perception score using item response theory (IRT). Patients were divided into three utilization categories: those paying with their NHIS card fully, those paying with their card and out-of-pocket (OOP), and those paying fully OOP. A multiple linear regression model was used to measure the association between NHIS utilization and overall perception.

Results

In general, NHIS utilization was negatively associated with overall perception, and the difference across utilization categories was higher among private facility users than public facility users. Among private facilities, those who paid fully with NHIS reported five points lower than those who paid fully OOP (P = 0.005). Among public facilities, the difference is only 1.7 (P = 0.4342).

Conclusion

NHIS utilization was a negative predictor for patient perceptions, but the differences are more nuanced according to type of facility. Future GDHS rounds should continue measuring perceptions in aid of policy to improve service delivery under the NHIS.
eAssessment: development of an electronic version of the Objective Structured Assessment of Debriefing tool to streamline evaluation of video recorded debriefings
Authors: Zamjahn John B , Baroni de Carvalho Raquel , Bronson Megan H , Garbee Deborah D , Paige John T
Published: August 2018

Objective

The Objective Structured Assessment of Debriefing (OSAD) is an evidence-based, 8-item tool that uses a behaviorally anchored rating scale in paper-based form to evaluate the quality of debriefing in medical education. The objective of this project was twofold: 1) to create an easy-to-use electronic format of the OSAD (eOSAD) in order to streamline data entry; and 2) to pilot its use on videoed debriefings.

Materials and Methods

The eOSAD was developed in collaboration with the LSU Health New Orleans Epidemiology Data Center using SurveyGizmo (Widgix Software, LLC, Boulder, CO, USA) software. The eOSAD was then piloted by 2 trained evaluators who rated 37 videos of faculty teams conducting pre-briefing and debriefing after a high-fidelity trauma simulation. Inter-rater reliability was assessed, and evaluators’ qualitative feedback was obtained.

Results

Inter-rater reliability was good [prebrief, intraclass correlation coefficient, ICC = 0.955 (95% CI, 0.912–0.977), P < .001; debrief, ICC = 0.853 (95% CI, 0.713–0.924), P < .001]. Qualitative feedback from evaluators found that the eOSAD was easy to complete, simple to read and add comments, and reliably stored data that were readily retrievable, enabling the smooth dissemination of information collected.

Discussion

The eOSAD features a secure login, sharable internet access link for distant evaluators, and the immediate exporting of data into a secure database for future analysis. It provided convenience for end-users, produced reliable assessments among independent evaluators, and eliminated multiple sources of possible data corruption.

Conclusion

The eOSAD tool format advances the post debriefing evaluation of videoed inter-professional team training in high-fidelity simulation.
Divergence and the Price of Uncertainty*
Authors: Schneider Paul , Trojani Fabio
Published: August 2018

Realized divergence measures the distinct realized moments associated with time-varying uncertainty. It is tradeable with divergence swaps engineered from delta-hedged option portfolios. Implied divergence decomposes the price of uncertainty into distinct implied moments, in a way that is consistent with established notions of a deviation from put-call symmetry in option markets. Empirically, market implied divergence and divergence risk premia vary substantially, in the time series, cross-sectionally and as a function of the investment horizon. Such variations can help to make the potential shortcomings of a model more directly visible.
Morphology of prestellar cores in pressure-confined filaments
Authors: Heigl S , Gritschneder M , Burkert A
Published: August 2018

Observations of prestellar cores in star-forming filaments show two distinct morphologies. While molecular line measurements often show broad cores, submillimetre continuum observations predominantly display pinched cores compared to the bulk of the filament gas. In order to explain how different morphologies arise, we use the gravitational instability model where prestellar cores form by growing density perturbations. The radial extent at each position is set by the local line mass. We show that the ratio of core radius to filament radius is determined by the initial line mass of the filament. Additionally, the core morphology is independent of perturbation length-scale and inclination, which makes it an ideal diagnostic for observations. Filaments with a line mass of less than half its critical value should form broad cores, whereas filaments with more than half its critical line-mass value should form pinched cores. For filaments embedded in a constant background pressure, the dominant perturbation growth times significantly differ for low and high line-mass filaments. Therefore, we predict that only one population of cores is present if all filaments within a region begin with similar initial perturbations.
Microsurgical Anatomy of the Jugular Process as an Anatomical Landmark to Access the Jugular Foramen: A Cadaveric and Radiological Study
Authors: Komune Noritaka , Matsuo Satoshi , Miki Koichi , Matsushima Ken , Akagi Yojiro , Kurogi Ryota , Iihara Koji , Matsushima Toshio , Inoue Tooru , Nakagawa Takashi
Published: August 2018

BACKGROUND

The jugular process forms the posteroinferior surface of the jugular foramen and is an important structure for surgical approaches to the foramen. However, its morphological features have not been well described in modern texts.

OBJECTIVE

To elucidate the microsurgical anatomy of the jugular process and examine its morphological features.

METHODS

Five adult cadaveric specimens were dissected in a cadaveric study, and computed tomography data from 31 heads (62 sides) were examined using OsiriX (Pixmeo SARL, Bernex, Switzerland) to elucidate the morphological features of the jugular process.

RESULTS

The cadaveric study showed that it has a close relationship with the sigmoid sinus, jugular bulb, rectus capitis lateralis, lateral atlanto-occipital ligament, and lateral and posterior condylar veins. The radiographic study showed that 9/62 sigmoid sinuses protruded inferiorly into the jugular process and that in 5/62 sides, this process was pneumatized. At the entry of the jugular foramen, if the temporal bone has a bulb-type jugular bulb, and if surgery concerns the right side of the head, the superior surface of the jugular process is more likely to be steep.

CONCLUSION

The jugular process forms the posteroinferior border of the jugular foramen. Resection of the jugular process is a critical step for opening the jugular foramen from the posterior and lateral aspects. Understanding the morphological features of the jugular process, and preoperative and radiographical examination of this process thus help skull base surgeons to access the jugular foramen.
Electoral Rules and Legislators’ Productivity
Authors: Akirav Osnat
Published: August 2018

Over the years, there have been a variety of changes to candidate selection methods for the Israeli Knesset. As a result, there have been changes in the way the Knesset functions. This study investigates whether these changes have made legislators more productive. To explore this issue, we used Akirav’s (2016) legislative productivity scale with data from the 14th, 16th and 19th Knesset (Israel’s parliament) terms to test several hypotheses. We found that in Israel, the candidate selection process affects legislators’ productivity, with the 19th Knesset proving the most productive. Nevertheless, in Israel, legislators’ productivity does not affect the likelihood of them being reelected.
Epidemiology of ICU-acquired pneumonia
Authors: Ferrer Miquel , Torres Antoni
Published: August 2018

Purpose of review

Review of the epidemiology of ICU-acquired pneumonia, including both ventilator-associated pneumonia (VAP) and hospital-acquired pneumonia (HAP) in nonventilated ICU patients, with critical review of the most recent literature in this setting.

Recent findings

The incidence of ICU-acquired pneumonia, mainly VAP has decrease significantly in recent years possibly due to the generalized implementation of preventive bundles. However, the exact incidence of VAP is difficult to establish due to the diagnostic limitations and the methods employed to report rates. Incidence rates greatly vary based on the studied populations. Data in the literature strongly support the relevance of intubation, not ventilatory support, in the development of HAP in ICU patients, but also that the incidence of HAP in nonintubated patients is not negligible. Despite the fact of a high crude mortality associated with the development of VAP, the overall attributable mortality of this complication was estimated in 13%, with higher mortality rates in surgical patients and those with mid-range severity scores at admission. Mortality is consistently greatest in patients with HAP who require intubation, slightly less in VAP, and least for nonventilated HAP. The economic burden of ICU acquired pneumonia, particularly VAP, is important. The increased costs are mainly related to the longer periods of ventilatory assistance and ICU and hospital stays required by these patients. However, the different impact of VAP on economic burden among countries is largely dependent on the different costs associated with heath care.

VAP has significant impact on mortality mainly in surgical patients and those with mid-range severity scores at admission. The economic burden on ICU-acquired pneumonia depends mainly on the increased length of stay of these patients.
Self-Reported Management of IV Fluids and Fluid Accumulation in Children With Acute Respiratory Failure*
Authors: Hassinger Amanda B. , Valentine Stacey L.
Published: August 2018

Objectives:

Observational studies have shown that fluid overload is independently associated with increased morbidity in critically ill children, especially with respiratory pathology. It is unknown if recent evidence has influenced clinical practice. We sought to describe current IV fluid management in pediatric acute respiratory distress syndrome.

Design:

Multinational, cross-sectional electronic survey.

Setting:

Pediatric Acute Lung Injury and Sepsis Investigators Network.

Subjects:

Pediatric intensivists.

Interventions:

None.

Measurements and Main Results:

One-hundred fifty-four respondents (43% response rate) had a median 10 years of experience (Q1–Q3, 4–17.8), in ICUs with a median 24 beds (18–36), where 86% provided extracorporeal membrane oxygenation. For maintenance IV fluid, 96% used the “4-2-1” rule to determine rate, and 59% used dextrose with normal saline for content. For fluid resuscitation, 77% use normal saline in 10 milliliters per kilogram aliquots (42%) or as fluid challenges (37%). Less than 20% of respondents reported resuscitating with 20 mL/kg boluses. Documented intake over output is the favored vital sign to assess (75% vs 57%) and guide fluid management (97% vs 14%) over central venous pressure. The majority of respondents chose 10% fluid overload as the threshold to act in children with pediatric acute respiratory distress syndrome. The majority (77%) agreed that fluid accumulation contributes to worse outcomes in pediatric acute respiratory distress syndrome and should be treated. Ninety-one percent reported conservative fluid management in pediatric acute respiratory distress syndrome is likely to be beneficial or protective.

Conclusions:

Pediatric intensivists agree that acting on 10% fluid overload in children with pediatric acute respiratory distress syndrome is important. Decisions are being made largely using intake and output documentation, not central venous pressure. These findings are important for future pediatric acute respiratory distress syndrome interventional trials.
Comparing Percutaneous to Open Access for Extracorporeal Membrane Oxygenation in Pediatric Respiratory Failure
Authors: Cairo Sarah B. , Arbuthnot Mary , Boomer Laura , Dingeldein Michael W. , Feliz Alexander , Gadepalli Samir , Newton Christopher R. , Puligandla Pramod , Ricca Robert , Rycus Peter , Vogel Adam M. , Yu Guan , Chen Ziqiang , Rothstein David H.
Published: August 2018

Objectives:

Evaluate trends in method of access (percutaneous cannulation vs open cannulation) for pediatric extracorporeal membrane oxygenation and determine the effects of cannulation method on morbidity and mortality.

Design:

Retrospective cohort study.

Setting and Subjects:

The Extracorporeal Life Support Organization’s registry was queried for pediatric patients on extracorporeal membrane oxygenation for respiratory failure from 2007 to 2015.

Inverventions:

None.

Measurements and Main Results:

Of 3,501 patients identified, 77.2% underwent open cannulation, with the frequency of open cannulation decreasing over the study period from approximately 80% to 70% (p < 0.001). Percutaneous cannulation patients were more commonly male (24.2% vs 21.5%; p = 0.01), older (average 7.6 vs 4.5 yr; p < 0.001), and heavier (average 33.0 vs 20.2 kg; p < 0.001). Subset analysis of patients on venovenous extracorporeal membrane oxygenation revealed higher rates of mechanical complications due to blood clots (28.9% vs 22.6%; p = 0.003) or cannula problems (18.9% vs 12.7%; p < 0.001), cannula site bleeding (25.3% vs 20.2%; p = 0.01) and increased rates of cannula site repair in the open cannulation cohort. Limb related complications were not significantly different on subset analysis for venovenous extracorporeal membrane oxygenation patients stratified by access site. Logistic regression analysis revealed that method of access was not associated with a difference in mortality.

Conclusions:

The proportion of pediatric patients undergoing percutaneous extracorporeal membrane oxygenation cannulation is increasing. Mechanical and physiologic complications occur with both methods of cannulation, but percutaneous cannulation appears safe in this cohort. Further analysis is needed to evaluate long-term outcomes with this technique.
Advancing Randomized Controlled Trials in Pediatric Critical Care: The Perspectives of Trialists
Authors: Duffett Mark , Swinton Marilyn , Brouwers Melissa , Meade Maureen , Cook Deborah J.
Published: August 2018

Objectives:

Clinical research is a complex scientific and social enterprise. Our objective was to identify strategies that pediatric critical care trialists consider acceptable, feasible, and effective to improve the design and conduct randomized controlled trials in pediatric critical care.

Design:

Qualitative descriptive study using semistructured individual interviews.

Subjects:

We interviewed 26 pediatric critical care researchers from seven countries who have published a randomized controlled trial (2005–2015). We used purposive sampling to achieve diversity regarding researcher characteristics and randomized controlled trial characteristics.

Interventions:

None.

Measurements and Main Results:

Most participants (24 [92%]) were from high-income countries, eight (31%) had published more than one randomized controlled trial, 17 (65%) had published a multicenter randomized controlled trial, and eight (31%) had published a multinational randomized controlled trial. An important theme was “building communities”—groups of individuals with similar interests, shared experiences, and common values, bound by professional and personal relationships. Participants described a sense of community as a source of motivation and encouragement and as a means to larger, more rigorous trials, increasing researcher and clinician engagement and maintaining enthusiasm. Strategies to build communities stressed in-person interactions (both professional and social), capable leadership, and trust. Another important theme was “getting started.” Participants highlighted the importance of formal research training and high-quality experiential learning through collaboration on other’s projects, guided by effective mentorship. Also important was “working within the system”—ensuring academic credit for a range of contributions, not only for the principal investigator role. The longitudinal notion of “building on success” was also underscored as a cross-cutting theme.

Conclusions:

Coordinated, deliberate actions to build community and ensure key training and practical experiences for new investigators may strengthen the research enterprise in pediatric critical care. These strategies, potentially in combination with other novel approaches, may vitalize clinical research in this field.
Circadian Rhythm Disruption and Sepsis in Severe Trauma Patients
Authors: Coiffard Benjamin , Diallo Aissatou B. , Culver Aurélien , Mezouar Soraya , Hammad Emmanuelle , Vigne Coralie , Nicolino-Brunet Corine , Dignat-George Françoise , Baumstarck Karine , Boucekine Mohamed , Leone Marc , Mege Jean-Louis
Published: August 2018

Background:

Circadian rhythms are important regulators of immune functions. Admission to an intensive care unit may impact molecular clock activity and host response. Our objective was to assess and compare the immune circadian rhythms in trauma patients who develop and in those who do not develop sepsis.

Methods:

Blood samples were collected from severe trauma patients within 4 days after admission, with collections taking place every 4 h over a 24-h period. Cortisol and cytokines were measured with immunoassays. Whole-blood expression of 3 clock genes (Bmal1, Per2, and Per3) was studied by reverse transcription quantitative polymerase chain reaction. Neutrophils, monocytes, and lymphocytes were analyzed by flow cytometry. Patients with and without sepsis were compared with the cosinor mixed model to estimate mesors, amplitudes, and acrophases.

Results:

Thirty-eight patients were enrolled in the study, and 13 developed at least 1 septic episode. The septic patients had higher levels of cortisol than the nonseptic patients (mesor at 489 nmol/L vs. 405 nmol/L, P < 0.05) and delayed acrophases (22 h vs. 15 h, P < 0.05). They also had lower lymphocyte counts (mesor at 785 vs. 1,012 cells/μL, P < 0.05), higher neutrophil counts (mesor at 7,648 vs. 7,001 cells/μL, P < 0.05), and monocyte counts (mesor at 579 vs. 473 cells/μL, P < 0.05) than the nonseptic patients. Although no amplitude difference was identified, the acrophases were significantly different between the 2 groups for lymphocytes, interleukin 10 and tumor necrosis factor.

Conclusion:

We demonstrated that all trauma patients had impaired circadian rhythms of cortisol, cytokines, leukocytes, and clock genes. Early circadian disruption was associated with the occurrence of sepsis and might be a marker of sepsis severity.
Half of Postoperative Deaths After Hepatectomy may be Preventable
Authors: Khaoudy Iman , Farges Olivier , Boleslawski Emmanuel , Vibert Eric , Soubrane Olivier , Adham Mustapha , Mabrut Jean Yves , Christophe Laurent , Bachellier Philippe , Scatton Olivier , Le Treut Yves-Patrice , Regimbeau Jean Marc
Published: August 2018

Objective:

To perform a retrospective root-cause analysis of the causes of postoperative mortality after hepatectomy.

Background:

Mortality after liver resection has not decreased over the past decade.

Methods:

The study population was a prospective cohort of hepatectomies performed at hepatic, pancreatic, and biliary (HPB) centers between October 2012 and December 2014. Of the 1906 included patients, 90 (5%) died within 90 days of surgery. Perioperative data were retrieved from the original medical records. The root-cause analysis was performed independently by a senior HBP-surgeon and a surgical HBP-fellow. The objectives were to record the cause of death and then assess whether (1) the attending surgeon had identified the cause of death and what was it?, (2) the intra- and postoperative management had been appropriate, (3) the patient had been managed according to international guidelines, and (4) death was preventable. A typical root cause of death was defined.

Results:

The cause of death was identified by the index surgeon and by the root-cause analysis in 84% and 88% of cases, respectively. Intra- and postoperative management procedures were inadequate in 33% and 23% of the cases, respectively. Guidelines were not followed in 57% of cases. Overall, 47% of the deaths were preventable. The typical root cause of death was insufficient evaluation of the tumor stage or tumor progression in a patient with malignant disease resulting in a more invasive procedure than expected.

Conclusion:

Measures to ensure compliance with guidelines and (in the event of unexpected operative findings) better within-team communication should be implemented systematically.
Left-liver Adult-to-Adult Living Donor Liver Transplantation
Authors: Sánchez-Cabús Santiago , Cherqui Daniel , Rashidian Niki , Pittau Gabriella , Elkrief Laure , Vanlander Aude , Toso Christian , Fondevila Constantino , Cunha Antonio Sa , Berney Thierry , Castaing Denis , de Hemptinne Bernard , Fuster Josep , Rogiers Xavier , Adam René , Majno Pietro , García-Valdecasas Juan Carlos , Troisi Roberto I.
Published: August 2018

Objective:

To evaluate the European experience after Adult-to-adult living donor liver transplantation using the left liver (LL-aLDLT).

Summary Background Data:

LL-aLDLT decreases donor risk but provides a smaller graft that increases recipient risk as compared with right liver (RL-aLDLT). However, there is little knowledge of results obtained after LL-aLDLT in Europe.

Methods:

This is a European multicenter retrospective study which aims to analyze donor and recipient outcomes after 46 LL-aLDLT.

Results:

Seventy-six percent of the grafts were harvested by minimally invasive approach. Mean donor hospital stay was 7.5 ± 3.5 days. Donor liver function was minimally impaired, with 36 donors (78.3%) without any 90-day complication, and 4 (8.7%) presenting major complications. One, 3, and 5-year recipient survival was 90.9%, 82.7%, and 82.7%, respectively. However, graft survival was of 59.4%, 56.9%, and 56.9% at 1, 3, and 5 years respectively, due to a 26.1% urgent liver retransplantation (ReLT) rate, mainly due to SFSS (n = 5) and hepatic artery thrombosis (HAT, n = 5). Risk factor analysis for ReLT and HAT showed an association with a graft to body weight ratio (GBWR) <0.6% (P = 0.01 and P = 0.024, respectively) while SFSS was associated with a recipient MELD ≥14 (P = 0.019). A combination of donor age <45 years, MELD <14 and actual GBWR >0.6% was associated with a lower ReLT rate (0% vs. 33%, P = 0.044).

Conclusions:

Our analysis showed low donor morbidity and preserved liver function. Recipient outcomes, however, were hampered by a high ReLT rate. A strict selection of both donor and recipients is the key to minimize graft loss.
Impact of Centralized Management of Bariatric Surgery Complications on 90-day Mortality
Authors: Caiazzo Robert , Baud Gregory , Clément Guillaume , Lenne Xavier , Torres Fanelly , Dezfoulian Guelareh , Lebuffe Gilles , Kipnis Eric , Dervaux Benoit , Pattou Francois
Published: August 2018

Background and Aims:

The potential benefit of the centralization of Bariatric surgery (BS) remains debated. The aim of this study was to evaluate the impact on 90-day mortality of an innovative organization aiming at centralizing the care of severe postoperative complications of BS.

Study Design:

The centralization of care for postoperative complication after BS was implemented by French Authorities in 2013 in the Nord-Pas-de-Calais Region, France. This unique formalized network (OSEAN), coordinated by 1 tertiary referral center, enrolled all regional institutions performing bariatric surgery. Data were extracted from the medico-administrative database providing information on all patients undergoing BS between 2009 and 2016 in OSEAN (n = 22,928) and in Rest of France (n = 288,942). The primary outcome was the evolution of 90-day mortality before and after the implementation of this policy. Rest of France was used as a control group to adjust the results to improvement with time of BS outcomes.

Results:

The numbers of primary procedure and reoperations increased similarly before and after 2013 within OSEAN and in Rest of France. The 90-day mortality rate became significantly lower within OSEAN than in the rest of France after 2013 (0.03% vs 0.08%, P < 0.01). This difference was confirmed in multivariate analysis after adjustment to the procedure specific mortality (P < 0.04). The reduction of 90-day mortality was most visible for sleeve gastrectomy.

Conclusion:

The implementation of centralized care for early postoperative complications after BS in OSEAN was associated with reduced 90-day mortality. Our results indicate that this reduction was not due to a lower incidence of complications but to the improvement of their management.
Analysis of the Learning Curve and Patient Outcomes of Endovascular Repair of Thoracoabdominal Aortic Aneurysms Using Fenestrated and Branched Stent Grafts
Authors: Schneider Darren B. , Agrusa Christopher J. , Ellozy Sharif H. , Connolly Peter H. , Meltzer Andrew J. , Graham Ashley R. , Michelassi Fabrizio
Published: August 2018

Objective:

To evaluate the outcomes and learning curve of fenestrated and branched endovascular repair (F/BEVAR) of thoracoabdominal aneurysms.

Summary of Background Data:

Endovascular aneurysm repair has reduced morbidity and mortality compared with open surgical repair. However, application to thoracoabdominal aneurysm repair remains limited by procedural complexity and device availability.

Methods:

Fifty patients treated in a prospective, nonrandomized, single-center Investigational Device Exemption (IDE) study between January 2014 and July 2017 were analyzed. Patients (mean age 75.6 ± 7.5 years; mean aneurysm diameter 67.3 ± 9.8 mm) underwent F/BEVAR of thoracoabdominal aneurysms (58% type IV; 42% type I-III) using custom-manufactured endografts. The experience was divided into 3 cohorts (Early: 1 to 17; Mid: 18 to 34; Late: 35 to 50) to evaluate learning curve effects on key process measures.

Results:

F/BEVAR included 194 visceral arteries (average 3.9 per patient). Technical success was 99.5% (193/194 targeted arteries). Thirty-day major adverse events (MAEs) included 3 (6%) deaths, 1 (2%) new-onset dialysis, 3 (6%) paraparesis/paraplegia, and 2 (4%) strokes. One-year survival was 79 ± 7%. Comparing the Early and Late groups revealed reductions in procedure time (452 ± 74 vs 362 ± 53 minutes; P = 0.0001), fluoroscopy time (130 ± 40 vs 99 ± 27 minutes; P = 0.016), contrast administration (157 ± 73 vs 108 ± 38 mL; P = 0.028), and estimated blood loss (EBL; 1003 ± 933 vs 481 ± 317 mL; P = 0.042). Intensive care unit (ICU) and total length of stay (LOS) decreased from 4 ± 3 to 2 ± 1 days and from 7 ± 6 to 5 ± 2 days, respectively, but was not statistically significant.

Conclusions:

Use of F/BEVAR for treatment of thoracoabdominal aneurysms is safe and effective. During this early experience, there was a significant improvement in key process measures reflecting improvements in technique and physician learning over time.