bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical algorithms for solving self-consistent field theory reversely for block copolymer systems
Authors: Sun De-Wen , Müller Marcus
Published: December 2018

Besides dictating the equilibrium phase diagram, the rugged free-energy landscape of AB block copolymers gives rise to a multitude of non-equilibrium phenomena. Self-consistent field theory (SCFT) can be employed to calculate the mean-field free energy, F[ϕAtarget], of a non-equilibrium unstable state that is characterized by a given spatial density distribution, ϕAtarget, in the incompressible system. Such a free-energy functional is the basis of describing the structure formation by dynamic SCFT techniques or the identification of minimum free-energy paths via the string method. The crucial step consists in computing the external potential fields that generate the given density distribution in the corresponding system of non-interacting copolymers, i.e., the potential-to-density relation employed in equilibrium SCFT calculations has to be inverted (reverse SCFT calculation). We describe, generalize, and evaluate the computational efficiency of two different numerical algorithms for this reverse SCFT calculation—the Debye-function algorithm based on the structure factor and the field-theoretic umbrella-potential (FUP) algorithm. In contrast to the Debye-function algorithm, the FUP algorithm only yields the exact mean-field values of the given target densities in the limit of a strong umbrella potential, and we devise a two-step variant of the FUP algorithm that significantly mitigates this issue. For Gaussian copolymers, the Debye-function algorithm is more efficient for highly unstable states that are far away from the equilibrium, whereas the improved FUP algorithm outperforms the Debye-function algorithm closer to metastable states and is easily transferred to more complex molecular architectures.
Remote heteroepitaxy across graphene: Hydrothermal growth of vertical ZnO microrods on graphene-coated GaN substrate
Authors: Jeong Junseok , Min Kyung-Ah , Kang Bong Kyun , Shin Dong Hoon , Yoo Jinkyoung , Yang Woo Seok , Lee Sang Wook , Hong Suklyun , Hong Young Joon
Published: December 2018

Semiconductor epitaxy on two-dimensional materials is beneficial for transferrable and flexible device applications. Graphene, due to the absence of permanent electric dipoles, cannot screen the electric field coming from the opposite side surface, allowing remote epitaxy for heteroepitaxy. This study demonstrates remote heteroepitaxy of ZnO microrods (MRs) on the GaN substrate across graphene layers via hydrothermal growth. Even the use of tri-layer graphene yields the remote heteroepitaxial MR arrays. Transmission electron microscopy reveals the remote heteroepitaxial relation between ZnO MRs and the GaN substrate despite the existence of graphene interlayers in between them. Density-functional theory calculations show that charge transfer along the z-direction at graphene/c-GaN possibly attract adatoms leading to remote heteroepitaxy, implying the field permeability of graphene. The ability of graphene to be released from the host substrate is exploited to exfoliate the overlayer MRs and regenerate the substrate.
Refractive index of [100] lithium fluoride under shock pressures up to 151 GPa
Authors: Young G. , Liu Xun , Leng Chunwei , Yang Jun , Huang Haijun
Published: December 2018

Single-crystal lithium fluoride(LiF) is a widely used window material in shock wave experiments to maintain the shock stress on the sample surface. It is transparent under shock compression up to ∼200 GPa, allowing the interferometer to record the movement of the monitored surface. However, the interferometer techniques require knowing the accurate refractive index of LiF under shock compression to deduce the true particle velocity. Although the refractive index of LiF under shock compression has long been studied, different experimental results diverge, especially in the high pressure region. Here, we used iron as the standard material to measure the refractive index of [100] LiF up to 151 GPa using two-stage light gas gun. Our results show that for the 1550 nm light, the true particle velocity (utrue) has a linear dependence on the apparent particle velocity (uapp), utrue = 12.26(2.07)m/s + 0.7759(0.0005)uapp, when the apparent particle velocity, uapp > 0.38 km/s.
Heterogeneous indirect reciprocity promotes the evolution of cooperation in structured populations
Authors: Wu Yu’e , Zhang Zhipeng , Chang Shuhua
Published: December 2018

A fundamental aspect of all biological system is cooperation. Human society is based to a large extent on mechanisms that favor cooperation. Indirect reciprocity is a crucial factor for the emergence and maintenance of cooperation in evolutionary games. In this work, we introduce a mechanism of heterogeneous indirect reciprocity in the prisoner’s dilemma game, where an altruistic attribute is considered. The so-called altruistic attribute refers to the trait that when an altruistic individual cooperates, its neighbors, regardless of their strategies, can gain additional benefits. Intuitively, altruistic cooperative agents seem to do only what is beneficial for others, but in fact, their neighbors tend to cooperate in order to maintain the cooperative strategies of altruistic individuals. In this way, the neighbors of cooperative altruistic individuals not only guarantee their own additional benefits, but also indirectly protect the income of altruistic individuals, which strengthens the links between cooperative individuals, thus promoting the evolution of cooperation. The robustness of the results is verified on homogeneous and heterogeneous networks. Moreover, the results of individual heterogeneity corroborate the existing evidence that heterogeneity, almost irrespective of its origin, promotes cooperative actions. Our conclusions might provide additional insights into understanding the roots of cooperation in social systems.
Factors associated with self-reported anal cancer screening history in men who have sex with men
Authors: Hicks Joseph T. , Hwang Lu-Yu , Baraniuk Sarah , White Margaret , Chiao Elizabeth Y. , Onwuka Nkechi , Ross Michael W. , Nyitray Alan G.
Published: December 2018

Background
Men who have sex with men (MSM) are at greater risk of developing anal cancer caused by human papillomavirus (HPV) than the rest of the general population. Currently, there are no formal national guidelines in the US advising men how and when to get anal cancer screening. We sought to assess differences in demographics, familiarity and anxiety about anal cancer among men who report having had anal cancer screening (i.e. anal cytology and/or a digital anorectal examination (DARE)). Methods: MSM were recruited to participate in a study to assess the feasibility of teaching self and partner anal examinations as a means of screening for anal cancer. Data for this secondary analysis were obtained using a written pre-test and a computer-assisted self-interview. Factors associated with screening were assessed with multivariable logistic regression to allow calculation of adjusted odds ratios (aORs). Results: Of the 197 participants with data, 145 (73.6%) reported having had anal cancer screening (either anal cytology, DARE or both) during their lifetime. Men who were younger, Black and HIV-negative were associated with decreased odds of reporting any type of anal cancer screening. For example, compared with White men, Black men were 80% less likely to report screening (aOR 0.2; 95% confidence interval (CI) 0.1–0.5). Self-perception of anal cancer knowledge was not associated with screening in multivariable analysis (aOR 1.6; 95% CI 0.6–3.9). Conclusions: Age, race and HIV status were independently associated with a history of anal cancer screening.
Phosphorus sorption on tropical soils with relevance to Earth system model needs
Authors: Brenner Julia , Porter Wesley , Phillips Jana R. , Childs Joanne , Yang Xiaojuan , Mayes Melanie A.
Published: December 2018

Phosphorus (P) availability critically limits the productivity of tropical forests growing on highly weathered, low-P soils. Although efforts to incorporate P into Earth system models (ESMs) provide an opportunity to better estimate tropical forest response to climate change, P sorption dynamics and controls on soil P availability are not well constrained. Here, we measured P and dissolved organic carbon (DOC) sorption isotherms on 23 soils from tropical Oxisol, Ultisol, Inceptisol, Andisol, and Aridisol soils using P concentrations from 10 to 500mg P L−1, and DOC concentrations from 10 to 100mg DOC L−1. Isotherms were fit to the Langmuir equation and parameters were related to soil characteristics. Maximum P sorption capacity (Qmax) was significantly correlated with clay content (ρ=0.658) and aluminium (Al)- or iron (Fe)-oxide concentrations (ρ=0.470 and 0.461 respectively), and the DOC Qmax was correlated with Fe oxides (ρ=0.491). Readily available soil characteristics could eventually be used to estimate Qmax values. Analysis of literature values demonstrated that the maximum initial P concentration added to soils had a significant impact on the resultant Qmax, suggesting that an insufficiently low initial P range could underestimate Qmax. This study improves methods for measuring P Qmax and estimating Qmax in the absence of isotherm analyses and provides key data for use in ESMs.
A common transcriptomic program acquired in the thymus defines tissue residency of MAIT and NKT subsets
Authors: Salou Marion , Legoux François , Gilet Jules , Darbois Aurélie , du Halgouet Anastasia , Alonso Ruby , Richer Wilfrid , Goubet Anne-Gaëlle , Daviaud Céline , Menger Laurie , Procopio Emanuele , Premel Virginie , Lantz Olivier
Published: December 2018

Mucosal-associated invariant T (MAIT) cells are abundant T cells with unique specificity for microbial metabolites. MAIT conservation along evolution indicates important functions, but their low frequency in mice has hampered their detailed characterization. Here, we performed the first transcriptomic analysis of murine MAIT cells. MAIT1 (RORγtneg) and MAIT17 (RORγt+) subsets were markedly distinct from mainstream T cells, but quasi-identical to NKT1 and NKT17 subsets. The expression of similar programs was further supported by strong correlations of MAIT and NKT frequencies in various organs. In both mice and humans, MAIT subsets expressed gene signatures associated with tissue residency. Accordingly, parabiosis experiments demonstrated that MAIT and NKT cells are resident in the spleen, liver, and lungs, with LFA1/ICAM1 interactions controlling MAIT1 and NKT1 retention in spleen and liver. The transcriptional program associated with tissue residency was already expressed in thymus, as confirmed by adoptive transfer experiments. Altogether, shared thymic differentiation processes generate “preset” NKT and MAIT subsets with defined effector functions, associated with specific positioning into tissues.
Evolution of closed curves by length-constrained curve diffusion
Authors: McCoy James , Wheeler Glen , Wu Yuhan
Published: December 2018

We show that any initial closed curve suitably close to a circle flows under length-constrained curve diffusion to a round circle in infinite time with exponential convergence. We provide an estimate on the total length of time for which such curves are not strictly convex. We further show that there are no closed translating solutions to the flow and that the only closed rotators are circles.
Large positive and negative values of Hardy’s 𝑍-function
Authors: Mahatab Kamalakshya
Published: December 2018

Let

Z
(
t
)
:=
ζ

(

1
2

+
i
t
)

χ

−

1
2

(

1
2

+
i
t
)

Z(t):=\zeta \left (\frac {1}{2}+it\right )\chi ^{-\frac {1}{2}}\left (\frac {1}{2}+it\right )

be Hardy’s function, where the Riemann zeta function

ζ
(
s
)

\zeta (s)

has the functional equation

ζ
(
s
)
=
χ
(
s
)
ζ
(
1
−
s
)

\zeta (s)=\chi (s)\zeta (1-s)

. We prove that for any

ϵ
>
0

\epsilon >0

,
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="StartLayout 1st Row 1st Column Blank 2nd Column a m p semicolon max Underscript upper T Superscript 3 slash 4 Baseline less-than-or-equal-to t less-than-or-equal-to upper T Endscripts upper Z left-parenthesis t right-parenthesis much-greater-than exp left-parenthesis left-parenthesis one half minus epsilon right-parenthesis StartRoot StartFraction log upper T log log log upper T Over log log upper T EndFraction EndRoot right-parenthesis 2nd Row 1st Column and 2nd Column a m p semicolon max Underscript upper T Superscript 3 slash 4 Baseline less-than-or-equal-to t less-than-or-equal-to upper T Endscripts minus upper Z left-parenthesis t right-parenthesis much-greater-than exp left-parenthesis left-parenthesis one half minus epsilon right-parenthesis StartRoot StartFraction log upper T log log log upper T Over log log upper T EndFraction EndRoot right-parenthesis period EndLayout">

a
m
p
;

max

T

3

/

4

≤
t
≤
T

Z
(
t
)
≫
exp
⁡

(

(

1
2

−
ϵ
)

log
⁡
T
log
⁡
log
⁡
log
⁡
T

log
⁡
log
⁡
T

)

and

a
m
p
;

max

T

3

/

4

≤
t
≤
T

−
Z
(
t
)
≫
exp
⁡

(

(

1
2

−
ϵ
)

log
⁡
T
log
⁡
log
⁡
log
⁡
T

log
⁡
log
⁡
T

)

.

\begin{align*} &\quad \max _{T^{3/4}\leq t\leq T} Z(t) \gg \exp \left (\left (\frac {1}{2}-\epsilon \right )\sqrt {\frac {\log T\log \log \log T}{\log \log T}}\right )\\ \text {and}\quad &\quad \max _{T^{3/4}\leq t\leq T}- Z(t) \gg \exp \left (\left (\frac {1}{2}-\epsilon \right )\sqrt {\frac {\log T\log \log \log T}{\log \log T}}\right ). \end{align*}
Thomae formula for abelian covers of ℂℙ¹
Authors: Kopeliovich Yaacov , Zemel Shaul
Published: December 2018

Abelian covers of

C
P

1

\mathbb {CP}^{1}

, with fixed Galois group

A
A

, are classified, as a first step, by a discrete set of parameters. Any such cover

X
X

, of genus

g
≥
1

g\geq 1

, say, carries a finite set of

A
A

-invariant divisors of degree

g
−
1

g-1

on

X
X

that produce nonzero theta constants on

X
X

. We show how to define a quotient involving a power of the theta constant on

X
X

that is associated with such a divisor

Δ
\Delta

, some polynomial in the branching values, and a fixed determinant on

X
X

that does not depend on

Δ
\Delta

, such that the quotient is constant on the moduli space of

A
A

-covers with the given discrete parameters. This generalizes the classical formula of Thomae, as well as all of its known extensions by various authors.
Macroscopic Schoen conjecture for manifolds with nonzero simplicial volume
Authors: Balacheff F. , Karam S.
Published: December 2018

We prove that given a hyperbolic manifold endowed with an auxiliary Riemannian metric whose sectional curvature is negative and whose volume is sufficiently small in comparison to the hyperbolic one, we can always find for any radius at least

1
1

a ball in its universal cover whose volume is bigger than the hyperbolic one. This result is deduced from a nonsharp macroscopic version of a conjecture by R. Schoen about scalar curvature, whose proof is a variation of an argument due to M. Gromov and is based on a smoothing technique. We take the opportunity of this work to present a full account of this technique, which involves simplicial volume and deserves to be better known.
Embolism resistance in stems of herbaceous Brassicaceae and Asteraceae is linked to differences in woodiness and precipitation
Authors: Dória Larissa Chacon , Meijs Cynthia , Podadera Diego Sotto , Del Arco Marcelino , Smets Erik , Delzon Sylvain , Lens Frederic
Published: December 2018

Background and Aims

Plant survival under extreme drought events has been associated with xylem vulnerability to embolism (the disruption of water transport due to air bubbles in conduits). Despite the ecological and economic importance of herbaceous species, studies focusing on hydraulic failure in herbs remain scarce. Here, we assess the vulnerability to embolism and anatomical adaptations in stems of seven herbaceous Brassicaceae species occurring in different vegetation zones of the island of Tenerife, Canary Islands, and merged them with a similar hydraulic–anatomical data set for herbaceous Asteraceae from Tenerife.

Methods

Measurements of vulnerability to xylem embolism using the in situ flow centrifuge technique along with light and transmission electron microscope observations were performed in stems of the herbaceous species. We also assessed the link between embolism resistance vs. mean annual precipitation and anatomical stem characters.

Key Results

The herbaceous species show a 2-fold variation in stem P50 from –2.1 MPa to –4.9 MPa. Within Hirschfeldia incana and Sisymbrium orientale, there is also a significant stem P50 difference between populations growing in contrasting environments. Variation in stem P50 is mainly explained by mean annual precipitation as well as by the variation in the degree of woodiness (calculated as the proportion of lignified area per total stem area) and to a lesser extent by the thickness of intervessel pit membranes. Moreover, mean annual precipitation explains the total variance in embolism resistance and stem anatomical traits.

Conclusions

The degree of woodiness and thickness of intervessel pit membranes are good predictors of embolism resistance in the herbaceous Brassicaceae and Asteraceae species studied. Differences in mean annual precipitation across the sampling sites affect embolism resistance and stem anatomical characters, both being important characters determining survival and distribution of the herbaceous eudicots.
Condition-dependent foraging strategies in a coastal seabird: evidence for the rich get richer hypothesis
Authors: Geary Brock , Walter Scott T , Leberg Paul L , Karubian Jordan
Published: December 2018

The degree to which foraging individuals are able to appropriately modify their behaviors in response to dynamic environmental conditions and associated resource availability can have important fitness consequences. Despite an increasingly refined understanding of differences in foraging behavior between individuals, we still lack detailed characterizations of within-individual variation over space and time, and what factors may drive this variability. From 2014 to 2017, we used GPS transmitters and accelerometers to document foraging movements by breeding adult Brown Pelicans (Pelecanus occidentalis) in the northern Gulf of Mexico, where the prey landscape is patchy and dynamic at various scales. Assessments of traditional foraging metrics such as trip distance, linearity, or duration did not yield significant relationships between individuals. However, we did observe lower site fidelity and less variation in energy expenditure in birds of higher body condition, despite a population-level trend of increased fidelity as the breeding season progressed. These findings suggest that high-quality individuals are both more variable and more efficient in their foraging behaviors during a period of high energetic demand, consistent with a “rich get richer” scenario in which individuals in better condition are able to invest in more costly behaviors that provide higher returns. This work highlights the importance of considering behavioral variation at multiple scales, with particular reference to within-individual variation, to improve our understanding of foraging ecology in wild populations.
Alfred: interactive multi-sample BAM alignment statistics, feature counting and feature annotation for long- and short-read sequencing
Authors: Rausch Tobias , Hsi-Yang Fritz Markus , Korbel Jan O , Benes Vladimir
Published: December 2018

Harmonizing quality control (QC) of large-scale second and third-generation sequencing datasets is key for enabling downstream computational and biological analyses. We present Alfred, an efficient and versatile command-line application that computes multi-sample QC metrics in a read-group aware manner, across a wide variety of sequencing assays and technologies. In addition to standard QC metrics such as GC bias, base composition, insert size and sequencing coverage distributions it supports haplotype-aware and allele-specific feature counting and feature annotation. The versatility of Alfred allows for easy pipeline integration in high-throughput settings, including DNA sequencing facilities and large-scale research initiatives, enabling continuous monitoring of sequence data quality and characteristics across samples. Alfred supports haplo-tagging of BAM/CRAM files to conduct haplotype-resolved analyses in conjunction with a variety of next-generation sequencing based assays. Alfred’s companion web application enables interactive exploration of results and comparison to public datasets.

Availability and implementation

Alfred is open-source and freely available at https://tobiasrausch.com/alfred/.

Supplementary information

Supplementary data are available at Bioinformatics online.
The role of astrocytes in seizure generation: insights from a novel in vitro seizure model based on mitochondrial dysfunction
Authors: Chan Felix , Lax Nichola Z , Voss Caroline Marie , Aldana Blanca Irene , Whyte Shuna , Jenkins Alistair , Nicholson Claire , Nichols Sophie , Tilley Elizabeth , Powell Zoe , Waagepetersen Helle S , Davies Ceri H , Turnbull Doug M , Cunningham Mark O
Published: December 2018

Many patients with mitochondrial disease have neurological symptoms, including drug-refractory epilepsy. Chan et al. develop an in vitro model of mitochondrial epilepsy with face and predictive validity. The model provides mechanistic insights into the role of astrocytes and the GABA-glutamate-glutamine cycle in driving seizure generation.
A Randomized, Double-blinded, Placebo-controlled Trial of Sitagliptin for Reducing Inflammation and Immune Activation in Treated and Suppressed Human Immunodeficiency Virus Infection
Authors: Dubé Michael P , Chan Ellen S , Lake Jordan E , Williams Brett , Kinslow Jennifer , Landay Alan , Coombs Robert W , Floris-Moore Michelle , Ribaudo Heather J , Yarasheski Kevin E
Published: December 2018

Background

Dipeptidyl peptidase-4 (DPP-4) inhibitors have pleotropic anti-inflammatory and immune regulatory effects in addition to glucoregulation. We evaluated inflammation and immune markers in suppressed human immunodeficiency virus (HIV) infection during treatment with the DPP-4 inhibitor sitagliptin.

Methods

Virologically suppressed adults with HIV without diabetes on stable antiretroviral therapy (ART) with ≥100/μL CD4 cells were randomized to 16 weeks of sitagliptin 100 mg/day vs placebo in a multicenter trial. The primary endpoint was the change in plasma soluble CD14 (sCD14) from baseline to week 15–16.

Results

Ninety participants were randomized, and 42 from each arm were included in per-protocol analyses. Participants were 45% non-Hispanic white, 38% non-Hispanic black, and 15% Hispanic, with a median age of 51 years; 83% were male; and the median CD4 count was 602 cells/μL. At week 15–16, there was no difference in sCD14 change between the 2 arms (P = .69). Relative to placebo, the sitagliptin arm had 47% greater decline in CXCL10 (95% confidence interval, –57% to –35%) at week 15 (P < .001). There were no significant between-arm differences in other soluble biomarkers, total CD4 and CD8 counts, or markers of lymphocyte or monocyte activation. Sitagliptin was well tolerated.

Conclusions

Sixteen weeks of sitagliptin had no effect on sCD14 levels in virologically suppressed participants with HIV. CXCL10, a chemokine involved in atherogenesis that predicts non-AIDS events during ART, declined markedly with sitagliptin. This suggests that DPP-4 inhibition has the potential to reduce cardiovascular morbidity in treated HIV infection.

Clinical Trials Registration

NCT01426438.
Rate of peri-procedural stroke observed with cerebral embolic protection during transcatheter aortic valve replacement: a patient-level propensity-matched analysis
Authors: Seeger Julia , Kapadia Samir R , Kodali Susheel , Linke Axel , Wöhrle Jochen , Haussig Stephan , Makkar Raj , Mehran Roxana , Rottbauer Wolfgang , Leon Martin
Published: December 2018

Aims

The role of cerebral embolic protection (CEP) in transcatheter aortic valve replacement (TAVR) remains controversial. Randomized trials have not been powered to demonstrate a reduction in stroke rates. The aim of this patient level pooled analysis was to validate the impact of the dual-filter CEP device (Claret Medical Inc., CA, USA) on peri-procedural stroke in a large number of TAVR patients.

Methods and results

Patients from the SENTINEL US IDE trial were combined with the CLEAN-TAVI and SENTINEL-Ulm study in a patient level pooled analysis (N = 1306). Propensity score matching was performed to adjust for possible confounders. The primary endpoint was procedural stroke within 72 h post-TAVR according to Valve Academic Research Consortium-2 criteria. The secondary endpoint was the combination of all-cause mortality or all-stroke within 72 h after TAVR. In the propensity-matched population, 533 patients underwent TAVR without CEP and 533 patients underwent TAVR with CEP. TAVR patients without vs. with CEP were similar with respect to baseline characteristics, procedural approach, or valve type. In patients undergoing TAVR with dual-filter CEP, procedural all-stroke was significantly lower compared with unprotected procedures [1.88% vs. 5.44%, odds ratio 0.35, 95% confidence interval (CI) 0.17–0.72, relative risk reduction 65%, P = 0.0028]. In addition, all-cause mortality and all-stroke were significantly lower (2.06% vs. 6.00%, odds ratio 0.34, 95% CI 0.17–0.68, relative risk reduction 66%, P = 0.0013).

Conclusion

Our findings suggest that TAVR with the dual-filter CEP device is associated with a significant lower rate of peri-procedural stroke compared with unprotected procedures. However, randomized trials are still needed to clarify this issue.
Motivation as a Mediator of the Relation Between Cognitive Reserve and Cognitive Performance
Authors: Vallet Fanny , Mella Nathalie , Ihle Andreas , Beaudoin Marine , Fagot Delphine , Ballhausen Nicola , Baeriswyl Marie , Schlemmer Morgane , Oris Michel , Kliegel Matthias , Desrichard Olivier
Published: December 2018

Objectives

Interindividual differences in cognitive aging may be explained by differences in cognitive reserve (CR) that are built up across the life span. A plausible but underresearched mechanism for these differences is that CR helps compensating cognitive decline by enhancing motivation to cope with challenging cognitive situations. Theories of motivation on cognition suggest that perceived capacity and intrinsic motivation may be key mediators in this respect.

Method

In 506 older adults, we assessed CR proxies (education, occupation, leisure activities), motivation (perceived capacity, intrinsic motivation), and a global measure of cognitive functioning.

Results

Perceived capacity, but not intrinsic motivation, significantly mediated the relation between CR and cognitive performance.

Discussion

Complementary with neurobiological and cognitive processes, our results suggest a more comprehensive view of the role of motivational aspects built up across the life span in determining differences in cognitive performance in old age.
A mecC allotype, mecC3, in the CoNS Staphylococcus caeli, encoded within a variant SCCmecC
Authors: MacFadyen A C , Harrison E M , Drigo I , Parkhill J , Holmes M A , Paterson G K
Published: December 2018

Background

Methicillin resistance in staphylococci is conferred by an alternative PBP (PBP2a/2′) with low affinity for most β-lactam antibiotics. PBP2a is encoded by mecA, which is carried on a mobile genetic element known as SCCmec. A variant of mecA, mecC, was described in 2011 and has been found in Staphylococcus aureus from humans and a wide range of animal species as well as a small number of other staphylococcal species from animals.

Objectives

We characterized a novel mecC allotype, mecC3, encoded by an environmental isolate of Staphylococcus caeli cultured from air sampling of a commercial rabbit holding.

Methods

The S. caeli isolate 82BT was collected in Italy in 2013 and genome sequenced using MiSeq technology. This allowed the assembly and comparative genomic study of the novel SCCmec region encoding mecC3.

Results

The study isolate encodes a novel mecA allotype, mecC3, with 92% nucleotide identity to mecC. mecC3 is encoded within a novel SCCmec element distinct from those previously associated with mecC, including a ccrAB pairing (ccrA5B3) not previously linked to mecC.

Conclusions

This is the first description of the novel mecC allotype mecC3, the first isolation of a mecC-positive Staphylococcus in Italy and the first report of mecC in S. caeli. Furthermore, the SCCmec element described here is highly dissimilar to the archetypal SCCmec XI encoding mecC in S. aureus and to elements encoding mecC in other staphylococci. Our report highlights the diversity of mecC allotypes and the diverse staphylococcal species, ecological settings and genomic context in which mecC may be found.
Effect of initial immunosuppression on long-term kidney transplant outcome in immunological low-risk patients
Authors: Michielsen Laura A , van Zuilen Arjan D , Verhaar Marianne C , Wisse Bram W , Kamburova Elena G , Joosten Irma , Allebes Wil A , van der Meer Arnold , Baas Marije C , Spierings Eric , Hack Cornelis E , van Reekum Franka E , Bots Michiel L , Drop Adriaan C A D , Plaisier Loes , Seelen Marc A J , Sanders Jan-Stephan F , Hepkema Bouke G , Lambeck Annechien J , Bungener Laura B , Roozendaal Caroline , Tilanus Marcel G J , Voorter Christien E , Wieten Lotte , van Duijnhoven Elizabeth M , Gelens Mariëlle A C J , Christiaans Maarten H L , van Ittersum Frans J , Nurmohamed Shaikh A , Lardy Neubury M , Swelsen Wendy , van der Pant Karlijn A , van der Weerd Neelke C , ten Berge Ineke J M , Bemelman Frederike J , Hoitsma Andries , van der Boog Paul J M , de Fijter Johan W , Betjes Michiel G H , Heidt Sebastiaan , Roelen Dave L , Claas Frans H , Otten Henderikus G , Hilbrands Luuk B
Published: December 2018

Background

Few studies have evaluated the effect of different immunosuppressive strategies on long-term kidney transplant outcomes. Moreover, as they were usually based on historical data, it was not possible to account for the presence of pretransplant donor-specific human-leukocyte antigen antibodies (DSA), a currently recognized risk marker for impaired graft survival. The aim of this study was to evaluate to what extent frequently used initial immunosuppressive therapies increase graft survival in immunological low-risk patients.

Methods

We performed an analysis on the PROCARE cohort, a Dutch multicentre study including all transplantations performed in the Netherlands between 1995 and 2005 with available pretransplant serum (n = 4724). All sera were assessed for the presence of DSA by a luminex single-antigen bead assay. Patients with a previous kidney transplantation, pretransplant DSA or receiving induction therapy were excluded from the analysis.

Results

Three regimes were used in over 200 patients: cyclosporine (CsA)/prednisolone (Pred) (n = 542), CsA/mycophenolate mofetil (MMF)/Pred (n = 857) and tacrolimus (TAC)/MMF/Pred (n = 811). Covariate-adjusted analysis revealed no significant differences in 10-year death-censored graft survival between patients on TAC/MMF/Pred therapy (79%) compared with patients on CsA/MMF/Pred (82%, P = 0.88) or CsA/Pred (79%, P = 0.21). However, 1-year rejection-free survival censored for death and failure unrelated to rejection was significantly higher for TAC/MMF/Pred (81%) when compared with CsA/MMF/Pred (67%, P < 0.0001) and CsA/Pred (64%, P < 0.0001).

Conclusion

These results suggest that in immunological low-risk patients excellent long-term kidney graft survival can be achieved irrespective of the type of initial immunosuppressive therapy (CsA or TAC; with or without MMF), despite differences in 1-year rejection-free survival.
Bronchiectasis and asthma: a dangerous liaison?
Authors: Crimi Claudia , Ferri Sebastian , Crimi Nunzio
Published: December 2018

Purpose of review

To explore the latest insight of the literature on the asthma/bronchiectasis phenotype providing an updated overview about epidemiological, clinical and biological evidence linking these two conditions.

Recent findings

An increasing body of literature has shown that the association of asthma and bronchiectasis is a frequent phenomenon leading to a more severe disease with frequent exacerbations. The mechanisms by which the two diseases are linked are still not well established but they share several clinical and immunological features and many comorbidities.

The early identification of bronchiectasis through high-definition computer tomography in patients with severe asthma is crucial in order to provide an adequate treatment for both diseases and therefore to better control symptoms, exacerbations and infections.
Do Mindfulness and Self-Compassion Predict Burnout in Pediatric Residents?
Authors: Kemper Kathi J. , McClafferty Hilary , Wilson Paria M. , Serwint Janet R. , Batra Maneesh , Mahan John D. , Schubert Charles J. , Staples Betty B. , Schwartz Alan ,   on behalf of the Pediatric Resident Burnout-Resilience Study Consortium
Published: December 2018

Purpose

Burnout symptoms are common among health professionals. Gaps remain in understanding both the stability of burnout and compassion over time and relationships among burnout, self-compassion, stress, and mindfulness in pediatric residents.

Method

The authors conducted a prospective cohort study of residents at 31 U.S. residency programs affiliated with the Pediatric Resident Burnout–Resilience Study Consortium. Residents completed online cross-sectional surveys in spring 2016 and 2017. The authors assessed demographic characteristics and standardized measures of mindfulness, self-compassion, stress, burnout, and confidence in providing compassionate care.

Results

Of 1,108 eligible residents, 872 (79%) completed both surveys. Of these, 72% were women. The prevalence of burnout was 58% and the level of mindfulness was 2.8 in both years; levels of stress (16.4 and 16.2) and self-compassion (37.2 and 37.6) were also nearly identical in both years. After controlling for baseline burnout levels in linear mixed-model regression analyses, mindfulness in 2016 was protective for levels of stress and confidence in providing compassionate care in 2017. Self-compassion in 2016 was protective for burnout, stress, and confidence in providing compassionate care in 2017; a one-standard-deviation increase in self-compassion score was associated with a decrease in the probability of burnout from 58% to 48%.

Conclusions

Burnout and stress were prevalent and stable over at least 12 months among pediatric residents. Mindfulness and self-compassion were longitudinally associated with lower stress and greater confidence in providing compassionate care. Future studies are needed to evaluate the effectiveness of training that promotes mindfulness and self-compassion in pediatric residents.
Is the Association Between Pregnancy Weight Gain and Fetal Size Causal?
Authors: Hutcheon Jennifer A. , Stephansson Olof , Cnattingius Sven , Bodnar Lisa M. , Johansson Kari
Published: December 2018

Background:

Observational cohort studies have consistently shown that maternal weight gain in pregnancy is positively associated with fetal size, but it is unknown whether the association is causal. This study investigated the effect of pregnancy weight gain on fetal growth using a sibling comparison design to control for unmeasured confounding by genetic and shared environmental factors.

Methods:

Our study population included 44,457 infants (21,680 women) with electronic medical records in the Stockholm–Gotland Obstetrical Database, 2008–2014. We standardized pregnancy weight gain into gestational age-specific z-scores. Fetal size was classified as birthweight (gram), and as small- and large-for-gestational-age birth (birthweight <10th or >90th percentiles, respectively). Our sibling comparison analyses used multivariable linear fixed effects models for birthweight and hybrid logistic fixed effects models for small- and large-for-gestational-age birth (SGA and LGA). We repeated analyses using conventional (unmatched) regression models.

Results:

Sibling comparison analyses showed a clinically meaningful association between weight gain and fetal size (e.g., adjusted difference of +89 g birthweight [95% CI = 82, 95 g]; adjusted risk ratios [aRR] for SGA of 0.80 [95% CI = 0.75, 0.86] per 1 z-score increase in weight gain for a woman of body mass index [BMI] = 25). These findings were consistent across the range of BMI. Estimates were only modestly attenuated compared with conventional approach (+97 g [95% CI = 92, 102 g], aRR for SGA of 0.70 [95% CI = 0.67, 0.73] per 1 z-score increase in weight gain).

Conclusion:

The positive association between pregnancy weight gain and fetal size we found using a sibling comparison design suggests that this relation has minimal confounding by familial factors that remain constant between pregnancies.
Upper Extremity Friction Burns in the Pediatric Patient: A 10-year Review
Authors: Marchalik Rachel , Rada Erin M. , Albino Frank P. , Sauerhammer Tina M. , Boyajian Michael J. , Rogers Gary F. , Oh Albert K.
Published: December 2018

Background:

Upper extremity friction burn due to powered home equipment is a growing problem in the pediatric population. The purpose of this study was to review the etiology, presentation, characteristics, and treatment of this particular type of pediatric mechanism of injury.

Methods:

A retrospective chart review using International Classification of Diseases, version 9, codes for patients treated at a large tertiary care, free-standing children’s hospital was performed to identify all patients presenting with an upper extremity friction burn from 2003 to 2012.

Results:

Sixty-nine patients sustained upper extremity friction burns. The average age at the time of injury was 3.3 years (range, 0.7–10.6) with presentation to our center occurring 16.6 days (range, 0–365 days) following injury. Mean follow-up was 23.3 months (range, 2–104). Mechanism of injury included treadmills (n = 63) and vacuum cleaners (n = 6). Twenty-eight operations were performed on 21 patients (30%). All patients requiring a surgical intervention sustained injury via treadmill mechanism (P = 0.0001). Unlike treadmill burns, vacuum cleaner injuries affected the dorsal hand or a single digit (P = 0.00004). Scar hyperpigmentation was more prevalent in these patients compared with the treadmill group (P = 0.003). All vacuum-induced burn patients had full range of motion and function with conservative treatment alone, whereas only 55.6% of treadmill burn patients had full recovery of range of motion and 50.8% recovery of full hand function.

Conclusions:

Friction burns from vacuum cleaners are less prevalent, have different injury patterns, and can be treated conservatively with excellent functional outcomes. Treadmill friction burns result in more significant injury and risk for dysfunction, requiring surgical intervention.
Scheduled Postoperative Ripcord Removal in Baerveldt 350 Implants: A Prospective, Randomized Trial
Authors: An Selena J. , Wen Joanne C. , Quist Michael S. , Mathenge Elizabeth W. , Vin Anita , Herndon Leon W.
Published: December 2018

Purpose:

Many surgeons remove the ripcord in the Baerveldt glaucoma drainage device to better control tube opening and intraocular pressure (IOP) lowering postoperatively. However, complications following Baerveldt implant surgery with or without ripcord removal are not well-characterized. We performed a prospective, randomized trial to test the hypothesis that scheduled ripcord removal decreases complications and final IOP.

Methods:

Eighty-one patients were enrolled and randomized to scheduled ripcord removal at postoperative week 3 or to observation. They were followed for 6 months, and outcomes were compared between the 2 groups.

Results:

Forty-four patients were randomized to scheduled ripcord removal and 37 to observation. The intervention group had a similar rate of total complications after ripcord removal (36% vs. 24%, P=0.24), a lower rate of tube fibrin obstruction (2.3% vs. 13.5%, P=0.05), and a larger decrease in the number of medications (1.3 vs. 0.49 fewer medications, P=0.01). The removal group’s mean IOP decrease was 8.6 mm Hg and success rate was 59%, defined as 5 mm Hg<final IOP≤15 mm Hg without further surgical intervention. Neither differed significantly from those of the control group.

Conclusions:

This study suggests that scheduled ripcord removal is correlated with similar overall recovery in comparison with spontaneous tube opening. This technique leads to similar IOP decrease and success rate and is also associated with a greater decrease in the number of medications, which may improve quality of life for patients. Additional studies could be useful in clarifying this technique’s role in the postoperative course among different patient populations.
Incidence of Open-angle Glaucoma in Newly Diagnosed Retinal Vein Occlusion: A Nationwide Population-based Study
Authors: Na Kyeong Ik , Jeoung Jin Wook , Kim Young Kook , Lee Won June , Park Ki Ho
Published: December 2018

Purpose:

The purpose of this study was to compare the incidence of open-angle glaucoma (OAG) in patients with newly diagnosed retinal vein occlusion (RVO) with that in the general population in order to determine the association between OAG and RVO.

Methods:

The Korean Health Insurance Review and Assessment (HIRA) data from 2011 through 2015 was analyzed in order to determine the incidence rates of OAG in the general population and in patients with newly diagnosed RVO based on the diagnostic code. The standardized incidence ratios (SIRs) of OAG in patients with RVO were determined with respect to the age- and sex-matched general population.

Results:

The incidence rate of OAG in the general population during the 3 years (2013 to 2015) was 233.98 per 100,000 person-years (95% CI, 233.21-234.76). A total of 31,722 patients with newly diagnosed RVO were identified in 2012 as the population at risk. The incidence rate of OAG in patients with RVO during the 3-year follow-up period was 1829.43 per 100,000 person-years (95% CI, 1745.49-1917.42). The expected incidence of OAG in patients with RVO was 433.69 during the 3-year follow-up period. On the other hand, the observed incidence of OAG was 1,741. The SIR of OAG in patients with RVO with reference to the general population was 4.01 (95% CI, 3.83-4.20).

Conclusions:

The incidence rate of OAG in patients with RVO is significantly higher than that in the general population.
The Relationship of Self-Report and Medication Possession With Glaucoma Medication Administration Success
Authors: Hein Aaron M. , Rosdahl Jullia A. , Bosworth Hayden B. , Woolson Sandra L. , Olsen Maren K. , Kirshner Miriam A. , Muir Kelly W.
Published: December 2018

Purpose:

Many glaucoma eye drop users cannot successfully self-administer drops, and observing patients’ drop technique can be time-consuming. We sought to examine the association of patient self-reported efficacy of eye drop technique and medication possession data as potential surrogate measures for actual drop administration success.

Patients and Methods:

In total, 137 adults with medically treated glaucoma were enrolled from a University eye clinic (n=54) or a Veteran Affairs (VA) eye clinic (n=83). All participants were asked, “How confident are you that you can get the medication into your eye?” Medication possession ratio (MPR), defined as the amount of eye drop available divided by the amount prescribed, was calculated for VA study site participants for 6 months. The main outcome was the correct eye drop technique, defined as the ability to get drops into the eye and to put only 1 drop into the eye at a time.

Results:

Among 117 participants who were “very confident” they could administer eye drops correctly, 95 participants (81%) displayed the correct drop technique. Of those who reported being less than “very confident” (n=18), 11 participants (61%) displayed correct drop technique (the Fisher exact test, P=0.07). For the VA sample, 20 participants with MPR<1.2, 20 participants with MPR=1.2 to 1.8, and 23 participants with MPR>1.8 displayed correct eye drop technique (the Fisher exact test, P=0.18).

Conclusions:

Self-reported administration success and MPR are not strongly associated with successful eye drop administration. Thus, direct observation of patients’ drop instillation may be the most effective means of determining patient efficacy.
Management of Atrial Fibrillation in Patients Undergoing Coronary Artery Bypass Grafting
Authors: Khiabani Ali J. , Adademir Taylan , Schuessler Richard B. , Melby Spencer J. , Moon Marc R. , Damiano Ralph J.
Published: December 2018

Untreated atrial fibrillation is associated with an increased risk of all-cause mortality and morbidity. Despite the current guidelines recommending surgical ablation of atrial fibrillation at the time of coronary artery bypass surgery, most patients with concomitant atrial fibrillation and coronary artery disease do not receive surgical ablation for their atrial fibrillation. This review reports the efficacy of different surgical ablation techniques used for the treatment of atrial fibrillation during coronary artery bypass. PubMed was systematically searched for studies reporting outcomes of concomitant surgical ablation in coronary artery bypass patients between January 2002 and March 2018. Data were independently extracted and analyzed by two investigators. Twenty-four studies were included. Twelve studies exclusively reported outcomes of surgical ablation in patients undergoing coronary artery bypass, whereas the remaining 12 reported outcomes of concomitant cardiac surgery with subgroup analysis. Only four studies performed the concomitant Cox-Maze procedure. Freedom from atrial tachyarrhythmia was reported as high as 98% at 1 year and 76% at 5 years with Cox-Maze procedure, whereas lesser lesion sets had more variable outcomes, ranging from 35% to 93%. In most studies, the addition of surgical ablation was not associated with increased morbidity and mortality. Although the Cox-Maze procedure had the greatest short- and long-term success rates, most studies comprising the evidence documenting the safety and efficacy of adding surgical ablation were of low or moderate quality. There was a great deal of heterogeneity among study populations, follow-up times, methods, and definition of failure. To establish a consensus regarding a surgical ablation technique for atrial fibrillation in coronary artery bypass population, larger multicenter randomized controlled studies need to be designed.