bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas sensing in 2D materials
Authors: Yang Shengxue , Jiang Chengbao , Wei Su-huai
Published: May 2017

Two-dimensional (2D) layered inorganic nanomaterials have attracted huge attention due to their unique electronic structures, as well as extraordinary physical and chemical properties for use in electronics, optoelectronics, spintronics, catalysts, energy generation and storage, and chemical sensors. Graphene and related layered inorganic analogues have shown great potential for gas-sensing applications because of their large specific surface areas and strong surface activities. This review aims to discuss the latest advancements in the 2D layered inorganic materials for gas sensors. We first elaborate the gas-sensing mechanisms and introduce various types of gas-sensing devices. Then, we describe the basic parameters and influence factors of the gas sensors to further enhance their performance. Moreover, we systematically present the current gas-sensing applications based on graphene, graphene oxide (GO), reduced graphene oxide (rGO), functionalized GO or rGO, transition metal dichalcogenides, layered III-VI semiconductors, layered metal oxides, phosphorene, hexagonal boron nitride, etc. Finally, we conclude the future prospects of these layered inorganic materials in gas-sensing applications.
Role of flexoelectric coupling in polarization rotations at the a-c domain walls in ferroelectric perovskites
Authors: Cao Ye , Chen Long-Qing , Kalinin Sergei V.
Published: May 2017

Ferroelectric and ferroelastic domain walls play important roles in ferroelectric properties. However, their couplings with flexoelectricity have been less understood. In this work, we applied phase-field simulation to investigate the flexoelectric coupling with ferroelectric a/c twin structures in lead ziconate titanate thin films. Local stress gradients were found to exist near twin walls that created both lateral and vertical electric fields through the flexoelectric effect, resulting in polarization inclinations from either horizontal or normal orientation, polarization rotation angles deviated from 90°, and consequently highly asymmetric a/c twin walls. By tuning the flexoelectric strengths in a reasonable range from first-principles calculations, we found that the transverse flexoelectric coefficient has a larger influence on the polarization rotation than longitudinal and shear coefficients. As polar rotations that commonly occur at compositional morphotropic phase boundaries contribute to the piezoelectric enhancement, this work calls for further exploration of alternative strain-engineered polar rotations via flexoelectricity in ferroelectric thin films.
Low-voltage shock-mitigated micro-electromechanical systems structure
Authors: Chen Ang , Nam Suhyun , Lai Ying-Cheng , Chae Junseok
Published: May 2017

We report a low-voltage, yet effective, micro-electromechanical systems (MEMS) structure capable of mitigating external mechanical disturbances, such as a physical shock. External shock onto MEMS devices can be catastrophic as a conventional single membrane may travel beyond stable oscillatory distances under shock and become irreparably damaged. However, the simple addition of a second membrane on top of the single membrane drastically reduces oscillatory distances by electrostatically holding the bottom membrane within stable oscillation. The added elements, in conjunction with a fine-control algorithm, mitigate the impact of a mechanical shock onto the MEMS device. From experimental findings, it is found that the dual-membrane structure effectively reduces the travel distance of the bottom membrane by 41.5%, upon deploying merely 0.565 V onto the additional membrane. The dynamic implementation of the shock mitigation method, using an on-board accelerometer as a trigger, delivered in-situ mitigation of shock on a dual-membrane MEMS structure.
Quantitative X-ray fluorescence computed tomography for low-Z samples using an iterative absorption correction algorithm
Authors: Huang Rong , Limburg Karin , Rohtla Mehis
Published: May 2017

X-ray fluorescence computed tomography is often used to measure trace element distributions within low-Z samples, using algorithms capable of X-ray absorption correction when sample self-absorption is not negligible. Its reconstruction is more complicated compared to transmission tomography, and therefore not widely used. We describe in this paper a very practical iterative method that uses widely available transmission tomography reconstruction software for fluorescence tomography. With this method, sample self-absorption can be corrected not only for the absorption within the measured layer but also for the absorption by material beyond that layer. By combining tomography with analysis for scanning X-ray fluorescence microscopy, absolute concentrations of trace elements can be obtained. By using widely shared software, we not only minimized the coding, took advantage of computing efficiency of fast Fourier transform in transmission tomography software, but also thereby accessed well-developed data processing tools coming with well-known and reliable software packages. The convergence of the iterations was also carefully studied for fluorescence of different attenuation lengths. As an example, fish eye lenses could provide valuable information about fish life-history and endured environmental conditions. Given the lens’s spherical shape and sometimes the short distance from sample to detector for detecting low concentration trace elements, its tomography data are affected by absorption related to material beyond the measured layer but can be reconstructed well with our method. Fish eye lens tomography results are compared with sliced lens 2D fluorescence mapping with good agreement, and with tomography providing better spatial resolution.
Arabidopsis
glycosylphosphatidylinositol-anchored protein LLG1 associates with and modulates FLS2 to regulate innate immunity
Authors: Shen Qiujing , Bourdais Gildas , Pan Huairong , Robatzek Silke , Tang Dingzhong
Published: May 2017

Significance

Recognition of pathogen-associated molecular patterns (PAMPs) by the host immune system is essential for activation of innate immunity in plants and animals. In plants, the receptor kinase FLAGELLIN SENSING 2 (FLS2) recognizes flagellin, a PAMP from bacteria. Here, we found that the glycosylphosphatidylinositol (GPI)-anchored protein LORELEI-LIKE GPI-ANCHORED PROTEIN 1 (LLG1) associates with FLS2 and regulates plant immunity by modulating FLS2 accumulation and signaling. LLG1 functions as a chaperone and coreceptor of FERONIA, a key component in pollen reception and development. This work identifies a shared component for immunity and development, and indicates that modulation of receptor kinases by membrane-localized GPI proteins could be a general mechanism for plants to respond to environmental and developmental cues.
Information socialtaxis and efficient collective behavior emerging in groups of information-seeking agents
Authors: Karpas Ehud D. , Shklarsh Adi , Schneidman Elad
Published: May 2017

Significance

From bacteria to humans, individual foraging has been a key example of complex behavior, often analyzed experimentally and theoretically, in terms of a trade-off between exploration and exploitation. Finding a source in a nonturbulent environment can be done by following the gradient of a signal, but in noisy environments, moving to maximize information about the source results in efficient searches. We present a model for group foraging, in which each agent aims to maximize its own information and minimize its informational overlap with others. The result is a highly efficient, robust, biologically plausible, and nearly optimal collective group behavior. This suggests information maximization from sensory and social sources as an optimization principle that can direct individual and group behavior.
Exceptional and rapid accumulation of anthropogenic debris on one of the world’s most remote and pristine islands
Authors: Lavers Jennifer L. , Bond Alexander L.
Published: May 2017

Significance

The isolation of remote islands has, until recently, afforded protection from most human activities. However, society’s increasing desire for plastic products has resulted in plastic becoming ubiquitous in the marine environment, where it persists for decades. We provide a comprehensive analysis of the quantity and source of beach-washed plastic debris on one of the world’s remotest islands. The density of debris was the highest recorded anywhere in the world, suggesting that remote islands close to oceanic plastic accumulation zones act as important sinks for some of the waste accumulated in these areas. As global plastic production continues to increase exponentially, it will further impact the exceptional natural beauty and biodiversity for which remote islands have been recognized.
Controllable load sharing for soft adhesive interfaces on three-dimensional surfaces
Authors: Song Sukho , Drotlef Dirk-Michael , Majidi Carmel , Sitti Metin
Published: May 2017

Significance

In transfer printing, robotics, and precision manufacturing, adhesion-controlled grasping of complex 3D surfaces is very challenging because the adhesive must be soft enough to enable intimate contact under light pressure but stiff enough to support high load and fracture strength. We address this dilemma by replacing the adhesive with a pressurized microfiber array that enables independent control of 3D conformability and bond strength. This architecture exhibits enhanced and robust adhesion on various sizes of 3D and deformable surfaces. In contrast to other microfiber adhesives, it has the area scalability of the natural gecko footpad. These features suggest that the proposed soft-gripping system can outperform conventional adhesive systems for a broad range of surface shapes and length scales.
RNA primer–primase complexes serve as the signal for polymerase recycling and Okazaki fragment initiation in T4 phage DNA replication
Authors: Spiering Michelle M. , Hanoian Philip , Gannavaram Swathi , Benkovic Stephen J.
Published: May 2017

Significance

The lagging-strand polymerase sometimes begins the synthesis of a new Okazaki fragment prior to finishing the previous fragment, creating a gap between the Okazaki fragments. The mechanism and signal that initiate this behavior have not been definitively identified. We demonstrate that primer–primase complexes left on the lagging ssDNA from primer synthesis have a residence time similar to the timescale of Okazaki fragment synthesis and the ability to block holoenzymes synthesizing DNA and stimulate the dissociation of the holoenzyme, triggering polymerase recycling. The collision with primer–primase complexes triggering early polymerase recycling has distinct advantages over previously proposed “signals.” Modeling of repeated cycles of Okazaki fragment initiation reproduced experimental data, providing insights into Okazaki fragment initiation and overall functioning of DNA replisomes.
Plate tectonic regulation of global marine animal diversity
Authors: Zaffos Andrew , Finnegan Seth , Peters Shanan E.
Published: May 2017

Significance

Understanding the processes that govern biodiversity is a central goal of biology. It has been hypothesized that global biodiversity is influenced by tectonically driven shifts in the arrangement of continental crust. We use globally distributed fossil data and quantitative analyses of shifting continental configurations in paleogeographic reconstructions to test this hypothesis. A significant component of the trajectory of marine animal diversity over the past 443 million years is attributable to the assembly and disassembly of the supercontinent Pangaea.
Effective control of complex turbulent dynamical systems through statistical functionals
Authors: Majda Andrew J. , Qi Di
Published: May 2017

Significance

Turbulent dynamical systems characterized by both a high-dimensional phase space and a large number of instabilities are ubiquitous among complex systems in science and engineering, including climate, material, and neural science. Control of these complex systems is a grand challenge, for example, in mitigating the effects of climate change or safe design of technology with fully developed shear turbulence. In complex turbulent dynamical systems, it is impossible to track and control the large dimension of instabilities, which strongly interact and exchange energy, and new control strategies are needed. The goal here is to propose an effective statistical control strategy for complex turbulent dynamical systems based on a recent statistical energy principle and statistical linear response theory.
Macedonia outside “Macedonia”
Authors: Takovski Aleksandar , Markovikj Nenad
Published: May 2017

The name dispute between Republic of Macedonia and Greece manifests itself in Greece’s objections to the use of the noun “Macedonia” or the adjective “Macedonian” to refer to any other ethnicity, culture, tradition and history except Greek. In order to promote itself as a sole claimant to the name, Greece has constructed a discourse which legitimizes its exclusive right to it, while at the same time it delegitimizes such right to Macedonia. However, this discourse does not only deny Macedonia the right to the name but it also denies Macedonia the right to discuss identity issues, while at the same time it obliterates Macedonian presence in the discourse in any relation to the disputed term. In this respect, this study seeks to analyze the specific linguistic strategies underlying these discursive effects.
Recreational Postrelease Mortality of Lake Trout in Lakes Superior and Huron
Authors: Sitar Shawn P. , Brenden Travis O. , He Ji X. , Johnson James E.
Published: May 2017

The effectiveness of fishing regulations that result in the release of some angler-caught fish depends on accurate knowledge of the postrelease mortality of those individuals. In the Laurentian Great Lakes, Lake Trout Salvelinus namaycush are a major component of recreational fisheries; across large regions of the lakes, they are managed with length limit and daily quota regulations assuming a 15% postrelease mortality rate. Due to concerns regarding the accuracy of that rate, we conducted a tagging study to estimate Lake Trout postrelease mortality in Lakes Superior and Huron, and we examined environmental and fishing factors that influenced the return rates of tagged fish. The basic study design was to compare tag return rates between two groups: (1) a treatment group comprising fish that were caught and released by anglers; and (2) a control group comprising fish that were caught via trap net and released. Tag return rates for the angler-caught group were evaluated in relation to depth of capture, surface temperature at release (ST), fishing method, anatomical hook site, play time, handling time, and barotrauma. Tag return rates for angler-caught fish declined significantly with increasing ST; the other factors’ effects on tag return rates were generally small. For Lake Superior, model-averaged (Akaike's information criterion) postrelease mortality estimates incorporating ST were 15.0% (SE = 5.6%) at STs less than 10°C, 42.6% (SE = 3.0%) at STs of 10–16°C, and 43.3% (SE = 3.6%) at STs greater than 16°C. Model-averaged estimates for Lake Huron were 52.5% (SE = 26.8%) at STs less than 10°C, 45.2% (SE = 14.0%) at STs of 10–16°C, and 76.4% (SE = 5.4%) at STs greater than 16°C. Based on these findings, alternative fishery management regulations that limit recreational catch-and-release angling of Lake Trout in the Great Lakes may be prudent. Current management policies based on an assumed 15% postrelease mortality are likely underestimating the total numbers of Lake Trout that are removed by recreational anglers.

Received January 26, 2017; accepted April 29, 2017 Published online June 26, 2017
Relative Morita equivalence of Cuntz–Krieger algebras and flow equivalence of topological Markov shifts
Authors: Matsumoto Kengo
Published: May 2017

We will introduce a relative version of imprimitivity bimodule and a relative version of strong Morita equivalence for pairs of

C
∗

C^*

-algebras

(

A

,

D

)

(\mathcal {A}, \mathcal {D})

such that

D

\mathcal {D}

is a

C
∗

C^*

-subalgebra of

A

\mathcal {A}

satisfying certain conditions. We will then prove that two pairs

(

A

1

,

D

1

)

(\mathcal {A}_1, \mathcal {D}_1)

and

(

A

2

,

D

2

)

(\mathcal {A}_2, \mathcal {D}_2)

are relatively Morita equivalent if and only if their relative stabilizations are isomorphic. In particular, for two pairs

(

O

A

,

D

A

)

(\mathcal {O}_A, \mathcal {D}_A)

and

(

O

B

,

D

B

)

(\mathcal {O}_B, \mathcal {D}_B)

of Cuntz–Krieger algebras with their canonical masas, they are relatively Morita equivalent if and only if their underlying two-sided topological Markov shifts

(

X
¯

A

,

σ
¯

A

)

(\overline {X}_A,\bar {\sigma }_A)

and

(

X
¯

B

,

σ
¯

B

)

(\overline {X}_B,\bar {\sigma }_B)

are flow equivalent. We also introduce a relative version of the Picard group

Pic

(

A

,

D

)

{\operatorname {Pic}}(\mathcal {A}, \mathcal {D})

for the pair

(

A

,

D

)

(\mathcal {A}, \mathcal {D})

of

C
∗

C^*

-algebras and study them for the Cuntz–Krieger pair

(

O

A

,

D

A

)

(\mathcal {O}_A, \mathcal {D}_A)

.
Completion of the universal I–Love–Q relations in compact stars including the mass
Authors: Reina Borja , Sanchis-Gual Nicolas , Vera Raül , Font José A.
Published: May 2017

In a recent paper, we applied a rigorous perturbed matching framework to show the amendment of the mass of rotating stars in Hartle's model. Here, we apply this framework to the tidal problem in binary systems. Our approach fully accounts for the correction to the Love numbers needed to obtain the universal I–Love–Q relations. We compute the corrected mass versus radius configurations of rotating quark stars, revisiting a classical paper on the subject. These corrections allow us to find a universal relation involving the second-order contribution to the mass δM. We thus complete the set of universal relations for the tidal problem in binary systems, involving four perturbation parameters, namely I, Love, Q and δM. These relations can be used to obtain the perturbation parameters directly from observational data.
Functional Outcomes and Delayed Cerebral Ischemia Following Nonperimesencephalic Angiogram-Negative Subarachnoid Hemorrhage Similar to Aneurysmal Subarachnoid Hemorrhage
Authors: Al-Mufti Fawaz , Merkler Alexander E , Boehme Amelia K , Dancour Elie , May Theresa , Schmidt J Michael , Park Soojin , Connolly E Sander , Lavine Sean D , Meyers Philip M , Claassen Jan , Agarwal Sachin
Published: May 2017

BACKGROUND

The angiogram-negative subarachnoid hemorrhage (SAH) literature includes patients with perimesencephalic hemorrhage, which is recognized to have a much better outcome than aneurysmal SAH.

OBJECTIVE

To evaluate the clinical outcomes of Nonperimesencephalic Angiogram-Negative SAH (NPAN-SAH).

METHODS

A prospective, spontaneous SAH database of 1311 patients that accrued between April 2006 and December 2014 was screened. All patients with NPAN-SAH and 2 consecutive negative cerebral angiograms were included.

RESULTS

We identified 191 (11%) from a total of 1311 patients with spontaneous SAH. Amongst angiogram-negative patients, 83 (4.9%) were adjudicated to have NPAN-SAH. Patient characteristics were similar across the groups, except NPAN-SAH patients were more likely to be men and had higher rates of diabetes. In a multivariable logistic regression model, NPAN-SAH patients were less likely to develop vasospasm, after adjusting for Fisher grade, sex, and diabetes (odds ratio [OR]: 0.197, 95% confidence interval [CI; 0.07-0.55], P = .002). In another adjusted model accounting for Hunt and Hess clinical grade, NPAN-SAH patients were also less likely to develop vasospasm (OR: 0.2, 95% CI [0.07-0.57], P = .002). We found no statistical significance between 2 groups for rebleed, developing hydrocephalus, seizures, or delayed cerebral ischemia. NPAN-SAH patients were equally associated with poor functional outcome (modified Rankin scale ≥3; OR: 1.16, 95% CI [0.615-2.20], P = .6420), and death (OR: 1.22, 95% CI [0.362-4.132], P = .7455) compared to aneurysmal SAH.

CONCLUSION

Although the risk of vasospasm may be lower, patients with NPAN-SAH are equally associated with delayed cerebral ischemia, poor outcome, and death as compared to patients with aneurysmal SAH. Furthers studies may be necessary to further clarify these findings
Size is the Most Important Predictor of Aneurysm Rupture Among Multiple Cerebral Aneurysms: Post Hoc Subgroup Analysis of Unruptured Cerebral Aneurysm Study Japan
Authors: Shojima Masaaki , Morita Akio , Nakatomi Hirofumi , Tominari Shinjiro
Published: May 2017

BACKGROUND

Multiple cerebral aneurysms are encountered in approximately 15% to 35% of patients harboring unruptured cerebral aneurysms. It would be of clinical value to determine which of them is most likely to rupture.

OBJECTIVE

To characterize features of the ruptured aneurysm relative to other concomitant fellow aneurysms in patients with multiple cerebral aneurysms.

METHODS

From a total of 5720 patients who were prospectively registered in the Unruptured Cerebral Aneurysm Study in Japan, a subgroup of patients with multiple cerebral aneurysms who developed subarachnoid hemorrhage was extracted for this post hoc analysis. Intrapatient comparisons of each aneurysm were carried out using aneurysm-specific factors such as size, location, and shape to identify predictors of rupture among the fellow aneurysms in a patient with multiple cerebral aneurysms.

RESULTS

Twenty-five patients with 62 aneurysms were identified from the total cohort of 5720 patients. With the distinctiveness in size, which means the aneurysm was the single largest among the multiple aneurysms, the ruptured aneurysm in each case was discriminated from the other coexisting aneurysms with a sensitivity of 0.76 and specificity of 0.86.

CONCLUSION

Our results suggest that the largest aneurysm is likely to rupture among coexisting aneurysms in a patient with multiple cerebral aneurysms.
False-Positive and False-Negative Results of Motor Evoked Potential Monitoring During Surgery for Intramedullary Spinal Cord Tumors
Authors: Kurokawa Ryu , Kim Phyo , Itoki Kazushige , Yamamoto Shinji , Shingo Tetsuro , Kawamoto Toshiki , Kawamoto Shunsuke
Published: May 2017

BACKGROUND

Motor evoked potential (MEP) recording is used as a method to monitor integrity of the motor system during surgery for intramedullary tumors (IMTs). Reliable sensitivity of the monitoring in predicting functional deterioration has been reported. However, we observed false positives and false negatives in our experience of 250 surgeries of IMTs.

OBJECTIVE

To delineate specificity and sensitivity of MEP monitoring and to elucidate its limitations and usefulness.

METHODS

From 2008 to 2011, 58 patients underwent 62 surgeries for IMTs. MEP monitoring was performed in 59 operations using transcranial electrical stimulation. Correlation with changes in muscle strength and locomotion was analyzed. A group undergoing clipping for unruptured aneurysms was compared for elicitation of MEP.

RESULTS

Of 212 muscles monitored in the 59 operations, MEP was recorded in 150 (71%). Positive MEP warnings, defined as amplitude decrease below 20% of the initial level, occurred in 37 muscles, but 22 of these (59%) did not have postoperative weakness (false positive). Positive predictive value was limited to 0.41. Of 113 muscles with no MEP warnings, 8 muscles developed postoperative weakness (false negative, 7%). Negative predictive value was 0.93. MEP responses were not elicited in 58 muscles (27%). By contrast, during clipping for unruptured aneurysms, MEP was recorded in 216 of 222 muscles (96%).

CONCLUSION

MEP monitoring has a limitation in predicting postoperative weakness in surgery for IMTs. False-positive and false-negative indices were abundant, with sensitivity and specificity of 0.65 and 0.83 in predicting postoperative weakness.
MITSuME observation of V404 Cygni in the 2015 outburst: Two optical variable components with different variability
Authors: Tachibana Yutaro , Yoshii Taketoshi , Hanayama Hidekazu , Kawai Nobuyuki
Published: May 2017

The black hole binary V404 Cygni (= GS 2023+338) had an outburst on 2015 June 15 after 26 years of its quiescence. We report on the multi-color optical observation (g΄, RC, and IC) of this object at the beginning of its outburst performed by the MITSuME 50 cm telescope in Akeno, Yamanashi, and the MURIKABUSHI 105 cm telescope at Ishigakijima Astronomical Observatory. Through time domain analysis of the multi-color light curves, we successfully decomposed the optical variations into two components: a highly variable and a less-variable component. The loci of the less-variable component in the color–color diagram are consistent with that of multi-temperature blackbody radiation, while those of the highly variable component trace out a power-law spectrum with a spectral index α ∼ 0.6–1.0. For the less-variable component, we argue that an irradiated disk with the innermost temperature higher than ∼2.0 × 104 K and the outermost temperature lower than ∼6.5 × 103 K is the most plausible source. The gradual rising trend of the light curve during our observation is probably due to the growing of the less-variable component. The observed spectral energy distribution from optical to ultraviolet can be expressed by a model consisting of a power-law component and an irradiated disk component.
Ethylene Signaling Is Important for Isoflavonoid-Mediated Resistance to Rhizoctonia solani in Roots of Medicago truncatula
Authors: Liu Yao , Hassan Samira , Kidd Brendan N. , Garg Gagan , Mathesius Ulrike , Singh Karam B. , Anderson Jonathan P.
Published: May 2017

The root-infecting necrotrophic fungal pathogen Rhizoctoniasolani causes significant disease to all the world’s major food crops. As a model for pathogenesis of legumes, we have examined the interaction of R. solani AG8 with Medicago truncatula. RNAseq analysis of the moderately resistant M. truncatula accession A17 and highly susceptible sickle (skl) mutant (defective in ethylene sensing) identified major early transcriptional reprogramming in A17. Responses specific to A17 included components of ethylene signaling, reactive oxygen species metabolism, and consistent upregulation of the isoflavonoid biosynthesis pathway. Mass spectrometry revealed accumulation of the isoflavonoid-related compounds liquiritigenin, formononetin, medicarpin, and biochanin A in A17. Overexpression of an isoflavone synthase in M. truncatula roots increased isoflavonoid accumulation and resistance to R. solani. Addition of exogenous medicarpin suggested this phytoalexin may be one of several isoflavonoids required to contribute to resistance to R. solani. Together, these results provide evidence for the role of ethylene-mediated accumulation of isoflavonoids during defense against root pathogens in legumes. The involvement of ethylene signaling and isoflavonoids in the regulation of both symbiont-legume and pathogen-legume interactions in the same tissue may suggest tight regulation of these responses are required in the root tissue.
The Impact of Steroidal Glycoalkaloids on the Physiology of Phytophthora infestans, the Causative Agent of Potato Late Blight
Authors: Dahlin Paul , Müller Marion C. , Ekengren Sophia , McKee Lauren S. , Bulone Vincent
Published: May 2017

Steroidal glycoalkaloids (SGAs) are plant secondary metabolites known to be toxic to animals and humans and that have putative roles in defense against pests. The proposed mechanisms of SGA toxicity are sterol-mediated disruption of membranes and inhibition of cholinesterase activity in neurons. It has been suggested that phytopathogenic microorganisms can overcome SGA toxicity by enzymatic deglycosylation of SGAs. Here, we have explored SGA-mediated toxicity toward the invasive oomycete Phytophthora infestans, the causative agent of the late blight disease in potato and tomato, as well as the potential for SGA deglycosylation by this species. Our growth studies indicate that solanidine, the nonglycosylated precursor of the potato SGAs α-chaconine and α-solanine, has a greater physiological impact than its glycosylated forms. All of these compounds were incorporated into the mycelium, but only solanidine could strongly inhibit the growth of P. infestans in liquid culture. Genes encoding several glycoside hydrolases with potential activity on SGAs were identified in the genome of P. infestans and were shown to be expressed. However, we found no indication that deglycosylation of SGAs takes place. We present additional evidence for apparent host-specific adaptation to potato SGAs and assess all results in terms of future pathogen management strategies.
Multicenter, real-life experience with checkpoint inhibitors and targeted therapy agents in advanced melanoma patients in Switzerland
Authors: Mangana Joanna , Cheng Phil F. , Kaufmann Corina , Amann Valerie C. , Frauchiger Anna L. , Stögner Viola , Held Ulrike , von Moos Roger , Michielin Olivier , Braun Ralph P. , Levesque Mitchell P. , Goldinger Simone M. , Dummer Reinhard
Published: May 2017

Metastatic melanoma is a highly aggressive disease. Recent progress in immunotherapy (IT) and targeted therapy (TT) has led to significant improvements in response and survival rates in metastatic melanoma patients. The current project aims to determine the benefit of the introduction of these new therapies in advanced melanoma across several regions of Switzerland. This is a retrospective multicenter analysis of 395 advanced melanoma patients treated with standard chemotherapy, checkpoint inhibitors, and kinase inhibitors from January 2008 until December 2014. The 1-year survival was 69% (n=121) in patients treated with checkpoint inhibitors (IT), 50% in patients treated with TTs (n=113), 85% in the IT+TT group (n=66), and 38% in patients treated with standard chemotherapy (n=95). The median overall survival (mOS) from first systemic treatment in the entire study cohort was 16.9 months. mOS of patients treated either with checkpoint or kinase inhibitors (n=300, 14.6 months) between 2008 and 2014 was significantly improved (P<0.0001) compared with patients treated with standard chemotherapy in 2008–2009 (n=95, 7.4 months). mOS of 61 patients with brain metastases at stage IV was 8.1 versus 12.5 months for patients without at stage IV (n=334), therefore being significantly different (P=0.00065). Furthermore, a significant reduction in hospitalization duration compared with chemotherapy was noted. Treatment with checkpoint and kinase inhibitors beyond clinical trials significantly improves the mOS in real life and the results are consistent with published prospective trial data.
Length of Stay, Mortality, Cost, and Perceptions of Care Associated With Transition From an Open to Closed Staffing Model in the Cardiac Intensive Care Unit
Authors: Katz Jason N. , Lishmanov Anton , van Diepen Sean , Yu Dongqing , Shen Haipeng , Pauley Eric , Bhatia Jatin , Buntaine Adam , Das Arun , Dangerfield Cristie , McLaughlin Brooke , Stouffer George A. , Kaul Prashant
Published: May 2017

Background:

Organizational models in the intensive care unit (ICU) have classically been described as either closed or open, depending on the presence or absence of a dedicated ICU team. Although a closed model has been shown to improve patient outcomes in medical and surgical ICUs, the merits of various care models have not been previously explored in the cardiac ICU (CICU) setting.

Methods:

From November 2012 to March 2014, data were prospectively collected on all admissions before and after transition from an open to closed CICU at our institution. Baseline clinical variables, illness severity, admission and discharge diagnoses, resource use, and outcomes were recorded. Anonymous surveys were also collected from nursing and resident trainee participants to evaluate the influence of unit structure on perceptions of care. Descriptive statistics were used, and logistic regression modeling was performed to examine the impact of unit structure on mortality.

Results:

The study consisted of 670 patients, 332 (49.6%) of whom were admitted to the open CICU model and 338 (50.4%) of whom were admitted to the closed model. Neither CICU nor hospital mortality differed between the open and closed units, though length of stay was shorter in the closed CICU. Additionally, nurses and resident trainees reported that the closed CICU allowed for better communication, collaboration, and education.

Conclusions:

Although there was no significant impact of unit structure on patient outcomes in this single-center study, the closed CICU model was associated with better perceptions of care.
PVCs, PVC-Induced Cardiomyopathy, and the Role of Catheter Ablation
Authors: Sharma Esseim , Arunachalam Karuppiah , Di Mengyang , Chu Antony , Maan Abhishek
Published: May 2017

Premature ventricular contractions (PVCs) are common arrhythmias noticed in the clinical setting because of premature depolarization of the ventricular myocytes. Although often thought to be reflective of underlying disease rather than intrinsically harmful, PVCs have recently been linked with worse outcomes in patients without significant cardiac disease. Long-term exposure to a high PVC burden can lead to the development of PVC-induced cardiomyopathy. The pathogenesis of this condition is poorly understood at the current time. Many studies have suggested that catheter ablation of these PVCs may result in reversal of the PVC-induced cardiomyopathy. This article will go over the natural history of PVCs and PVC-induced cardiomyopathy, as well as review the current literature on the role of catheter ablation in treating PVC-induced cardiomyopathy.
Effectiveness of 2-hour Troponin in High-risk Patients With Suspected Acute Coronary Syndrome
Authors: Bove Joseph , Hochman Steven , Miller Jacob , Artim Stephen
Published: May 2017

Background:

Research has shown the safety and effectiveness of drawing a standard troponin level at presentation and again at 2 hours in only low-risk patients. Because high-sensitivity troponins are not currently approved in the United States, we studied the utility of a standard troponin that is presently in use. Our goal was to determine if 2-hour standard troponin would be safe and effective in the evaluation of a high-risk cohort of patients never studied previously.

Methods:

We conducted a single-center prospective observational study of adult patients presenting to the emergency department with signs and symptoms suggestive of acute coronary syndrome. Patients were defined as high risk if the attending physician planned to admit or transfer the patient to the observation unit. History, Electrocardiography, Age, Risk factors, Troponin scores were calculated on all patients to provide verification that the individuals were high risk. The primary outcome was a composite of 30-day myocardial infarction, death, cardiac arrest with return of spontaneous circulation, or dysrhythmia. The secondary outcome was 30-day revascularization.

Results:

We included a total of 122 patients with an average follow-up of 112 days (minimum 30 days). A total of 86% of cases had History, Electrocardiography, Age, Risk factors, Troponin scores ≥4. The primary outcome was met in 22 (18%) patients, and the secondary outcome occurred in 7 (5.7%) patients. The negative predictive value of negative 2-hour troponins along with no significant delta troponin rise was 98.7%.

Conclusions:

Discharging patients thought to be high risk who have negative troponins at 0 and 2 hours and no delta troponin rise appears safe. No deaths occurred in follow-up. Larger studies are warranted.
Understanding Women's Sexual Behaviors That May Put Them at Risk for Human Papillomavirus–Related Neoplasias: What Should We Ask?
Authors: Kulkarni Amita , Tran Tram , Luis Christine , Raker Christina A. , Cronin Beth , Robison Katina
Published: May 2017

Objectives

Human papillomavirus is a multifocal infection that can involve the cervix, vagina, vulva, anus, and oropharynx. Our study aimed to determine whether standard sexual history questions regarding anal intercourse identify women participating in anal-related sexual practices.

Materials and Methods

A cross-sectional survey was conducted at the dysplasia clinic of a large academic medical center. Women presenting with human papillomavirus–related cervical, vulvar, or vaginal abnormalities were eligible. Participants completed a self-administered sexual history questionnaire that included standard sexual history questions and more detailed questions about sexual practices. Additional demographic information was obtained from chart review.

Results

A total of 149 eligible women were approached, 125 (84%) consented and enrolled (ages = 21–65 years). Forty-seven (44%) reported participating in some type of anal-related sexual practice: anal fingering, oral-anal penetration, or anal intercourse. Of those participating in anal-related practices, 5 (11%) reported only anal fingering or oral-anal penetration. Thus, adding the new anal questions detected an additional 5% of women with high-risk anal behaviors that may have been missed by the standard question (p = .06). Seventy-nine women (63%) reported receiving oral penetration of the vagina, and 102 (82%) reported receiving vaginal fingering. Fifty-nine women (47%) used sex toys: 58 (98%) used sex toys vaginally, with 5 (8.5%) using them also anally.

Conclusions

Women are willing to report their participation in a range of sexual practices. Of those who participated in anal practices, 11% did not have anal intercourse. Adding additional sexual health questions to clinical intake forms may enable clinicians to better counsel their patients on risky sexual behaviors.
Isolated Right Ventricular Mechanical Support: Outcomes and Prognosis
Authors: Mulaikal Teresa A. , Bell Laura H. , Li Boyangzi , Wagener Gebhard , Takayama Hiroo
Published: May 2017

Right ventricular (RV) failure that necessitates isolated mechanical support is extremely rare. Outcomes have not been described and are limited to case reports. We sought to evaluate this select group of patients and determine their 30 day and 1 year survival. We retrospectively reviewed the Mechanical Assist Device Database at Columbia University from 2007 to 2015. Inclusion criteria consisted of patients who received isolated RV assist devices (RVADs) without mechanical support of the left ventricle. We evaluated survival, duration of support, intensive care unit (ICU) length of stay, and adverse events. There were 55 patients who underwent RVAD placement between February 2007 and April 2015. Eleven of these patients received isolated RVADs in the absence of mechanical circulatory support of the left ventricle. Average duration of support was 13.6 days with a median duration of 12 days. Thirty day and 1 year survival was 72.7% and 54.6%, respectively. This case series is the first to describe 30 day and 1 year outcomes for patients with isolated RV mechanical support. We propose an interdisciplinary institutional algorithm based on our study population that maximizes medical therapy and then pursues invasive forms of mechanical support when end-organ damage persists.
Ultrasound-guided pericardiocentesis: a novel parasternal approach
Authors: Osman Adi , Wan Chuan Tan , Ab Rahman Jamalludin , Via Gabriele , Tavazzi Guido
Published: May 2017

Objective

The aim of this study was to evaluate a novel pericardiocentesis technique using an in-plane parasternal medial-to-lateral approach with the use of a high-frequency probe in patients with cardiac tamponade.

Background

Echocardiography is pivotal in the diagnosis of pericardial effusion and tamponade physiology. Ultrasound guidance for pericardiocentesis is currently considered the standard of care. Several approaches have been described recently, which differ mainly on the site of puncture (subxiphoid, apical, or parasternal). Although they share the use of low-frequency probes, there is absence of complete control of needle trajectory and real-time needle visualization. An in-plane and real-time technique has only been described anecdotally.

Methods and results

A retrospective analysis of 11 patients (63% men, mean age: 37.7±21.2 years) presenting with cardiac tamponade admitted to the tertiary-care emergency department and treated with parasternal medial-to-lateral in-plane pericardiocentesis was carried out. The underlying causes of cardiac tamponade were different among the population. All the pericardiocentesis were successfully performed in the emergency department, without complications, relieving the hemodynamic instability. The mean time taken to perform the eight-step procedure was 309±76.4 s, with no procedure-related complications.

Conclusion

The parasternal medial-to-lateral in-plane pericardiocentesis is a new technique theoretically free of complications and it enables real-time monitoring of needle trajectory. For the first time, a pericardiocentesis approach with a medial-to-lateral needle trajectory and real-time, in-plane, needle visualization was performed in a tamponade patient population.
The Development of the Chinese Intermittent Exotropia Questionnaire
Authors: Zhu Hui , Shen Ling , Yuan Chao-Qun , Xu Shu , Leng Zhen-Hua , Fu Zhu-Jun , Xiao Yun-Hua , Liu Hu
Published: May 2017

Purpose

The Intermittent Exotropia Questionnaire (IXTQ) is a child, proxy, and parent report of health-related quality of life specific to children with intermittent exotropia (IXT). The present study aimed to develop a Chinese-language version of the IXTQ (CIXTQ) and evaluate its validity and reliability when used in Chinese IXT children and their parents.

Methods

The IXTQ was translated into Chinese. One hundred seventy-five IXT children (2 to 17 years old) and 151 orthotropic control children (2 to 17 years old) along with one of their parents were recruited. Children 5 to 17 years old completed the 5- to 7-year-old or the 8- to 17-year-old child questionnaire of the CIXTQ according to their age. Parents of all children (2 to 17 years old) completed the proxy and parent questionnaires of the CIXTQ. Psychometric properties of the CIXTQ were examined for floor and ceiling effects, construct validity, item-internal consistency, discriminative validity, Cronbach α coefficient and test-retest reliability.

Results

No items were found to have strong floor or ceiling effects. Principal component analysis identified that the CIXTQ had a similar structure to the original English version. The median scores of each questionnaire in the CIXTQ among children with IXT and their parents were significantly lower than those among control subjects (P < .001). Cronbach α coefficients ranged from 0.869 to 0.931, and test-retest reliabilities ranged from 0.898 to 0.981, for each questionnaire in the CIXTQ.

Conclusions

The CIXTQ is a useful tool to evaluate the influence of IXT on health-related quality of life among Chinese IXT children and their parents.
Foveal Curvature and Asymmetry Assessed Using Optical Coherence Tomography
Authors: VanNasdale Dean A. , Eilerman Amanda , Zimmerman Aaron , Lai Nicky , Ramsey Keith , Sinnott Loraine T.
Published: May 2017

Purpose

The aims of this study were to use cross-sectional optical coherence tomography imaging and custom curve fitting software to evaluate and model the foveal curvature as a spherical surface and to compare the radius of curvature in the horizontal and vertical meridians and test the sensitivity of this technique to anticipated meridional differences.

Methods

Six 30-degree foveal-centered radial optical coherence tomography cross-section scans were acquired in the right eye of 20 clinically normal subjects. Cross sections were manually segmented, and custom curve fitting software was used to determine foveal pit radius of curvature using the central 500, 1000, and 1500 μm of the foveal contour. Radius of curvature was compared across different fitting distances. Root mean square error was used to determine goodness of fit. The radius of curvature was compared between the horizontal and vertical meridians for each fitting distance.

Results

There radius of curvature was significantly different when comparing each of the three fitting distances (P < .01 for each comparison). The average radii of curvature were 970 μm (95% confidence interval [CI], 913 to 1028 μm), 1386 μm (95% CI, 1339 to 1439 μm), and 2121 μm (95% CI, 2066 to 2183) for the 500-, 1000-, and 1500-μm fitting distances, respectively. Root mean square error was also significantly different when comparing each fitting distance (P < .01 for each comparison). The average root mean square errors were 2.48 μm (95% CI, 2.41 to 2.53 μm), 6.22 μm (95% CI, 5.77 to 6.60 μm), and 13.82 μm (95% CI, 12.93 to 14.58 μm) for the 500-, 1000-, and 1500-μm fitting distances, respectively. The radius of curvature between the horizontal and vertical meridian radii was statistically different only in the 1000- and 1500-μm fitting distances (P < .01 for each), with the horizontal meridian being flatter than the vertical.

Conclusions

The foveal contour can be modeled as a sphere with low curve fitting error over a limited distance and capable of detecting subtle foveal contour differences between meridians.
Alloimmunity But Not Viral Immunity Promotes Allograft Loss in a Mouse Model of Polyomavirus-Associated Allograft Injury
Authors: Kim Steven C. , Wang Jun , Dong Ying , Mathews David V. , Albrecht Joshua A. , Breeden Cynthia P. , Farris Alton B. , Lukacher Aron E. , Ford Mandy L. , Newell Kenneth A. , Adams Andrew B.
Published: May 2017

Background

The interplay between viral infection and alloimmunity is known to influence the fate of transplanted organs. Clarifying how local virus-associated inflammation/injury and antiviral immunity can alter host alloimmune responses in transplantation remains a critical question.

Methods

We used a mouse model of polyomavirus (PyV) infection and kidney transplantation to investigate the roles of direct viral pathology, the antiviral immune response, and alloimmunity in the pathogenesis of PyV-associated allograft injury. We have previously shown that an effective primary T cell response is required in PyV-associated graft injury.

Results

Here we show that the transfer of primed antidonor, but not antiviral, T cells results in PyV-associated allograft injury. In further studies, we use a surrogate minor antigen model (ovalbumin) and show that only antidonor specific T cells and not antiviral specific T cells are sufficient to mediate injury. Lastly, we demonstrate that local but not systemic virus-mediated inflammation and injury within the graft itself are required.

Conclusions

These data suggest that in this mouse model, the predominant mechanism of allograft injury in PyV-associated injury is due to an augmented alloimmune T cell response driven by virus-induced inflammation/injury within the graft. These studies highlight the important interplay between viral infection and alloimmunity in a model system.
Clustering: how much bias do we need?
Authors: Lorimer Tom , Held Jenny , Stoop Ruedi
Published: May 2017

Scientific investigations in medicine and beyond increasingly require observations to be described by more features than can be simultaneously visualized. Simply reducing the dimensionality by projections destroys essential relationships in the data. Similarly, traditional clustering algorithms introduce data bias that prevents detection of natural structures expected from generic nonlinear processes. We examine how these problems can best be addressed, where in particular we focus on two recent clustering approaches, Phenograph and Hebbian learning clustering, applied to synthetic and natural data examples. Our results reveal that already for very basic questions, minimizing clustering bias is essential, but that results can benefit further from biased post-processing.

This article is part of the themed issue ‘Mathematical methods in medicine: neuroscience, cardiology and pathology’.