bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced brain amyloid burden in elderly patients with narcolepsy type 1
Authors: Gabelle Audrey , Jaussent Isabelle , Bouallègue Fayçal Ben , Lehmann Sylvain , Lopez Régis , Barateau Lucie , Grasselli Caroline , Pesenti Carole , de Verbizier Delphine , Béziat Séverine , Mariano‐Goulart Denis , Carlander Bertrand , Dauvilliers Yves ,   the Alzheimer's Disease Neuroimaging Initiative,   Multi‐Domain Intervention Alzheimer's Prevention Trial study groups
Published: November 2018

Objective

To determine whether brain amyloid burden in elderly patients with narcolepsy type 1 (NT1) is lower than in controls, and to assess in patients with NT1 the relationships between amyloid burden, cerebral spinal fluid (CSF) markers of Alzheimer disease (AD), CSF orexin‐A, and cognitive profile.

Methods

Cognitive and 18F‐florbetapir positron emission tomography (PET) data were compared in patients with NT1 aged ≥ 65 years (n = 23) and in age‐ and sex‐matched controls free of clinical dementia selected from the Alzheimer's Disease Neuroimaging Initiative (ADNI; n = 69) and the Multi‐Domain Intervention Alzheimer's Prevention Trial (MAPT‐18F AV45‐PET; n = 23) cohorts. The standardized uptake values (SUVs) of the cortical retention index for 6 regions of interest were computed and averaged to create a mean SUV ratio normalized to 3 subcortical reference regions (cerebellum, pons, and a composite region). A cortical/cerebellum SUV ratio ≥ 1.17 defined positive PET amyloid.

Results

Lower cortical amyloid burden was observed in the NT1 than in the ADNI and MAPT‐AV45 groups (mean cortical/cerebellum SUV ratios = 0.95 ± 0.15, 1.11 ± 0.18 [p < 0.0001], and 1.14 ± 0.17 [p = 0.0005], respectively). Similar results were obtained with all subcortical reference regions and for all cortical regions of interest, except cingulum. Only 1 patient with NT1 (4.4%) had positive PET amyloid compared with 27.5% in the ADNI and 30.4% in the MAPT‐AV45 group. In the NT1 group, cortical or regional amyloid load was not associated with CSF orexin‐A, CSF AD biomarkers, or neuropsychological profile.

Interpretation

Lower brain amyloid burden, assessed by 18F‐florbetapir PET, in patients with NT1 suggests delayed appearance of amyloid plaques. ANN NEUROL 2019;85:74–83.
Transient Glass Formation around a Quadrupolar Photoexcited Dye in a Strongly H‐Bonding Liquid Observed by Transient 2D‐IR Spectroscopy
Authors: Dereka Bogdan , Helbing Jan , Vauthey Eric
Published: November 2018

Intermolecular H‐bonding dynamics around a photoexcited quadrupolar dye is directly observed using transient 2D‐IR spectroscopy. Upon solvent‐induced symmetry breaking, the H‐bond accepting abilities of the two nitrile end‐groups change drastically, and in extremely protic (superprotic) solvents, a tight H‐bond complex forms at one end. The time evolution of the 2D C≡N lineshape in methanol points to rapid, 2–3 ps, spectral diffusion due to fluctuations of the H‐bonding network. Similar behavior is observed in a superprotic solvent shortly after photoexcitation of the dye. However, at later times, the completely inhomogeneous band does not exhibit spectral diffusion for at least 5 ps, pointing to a glass‐like environment around one side of the dye. About half of the excited dyes show this behavior attributed to the tight H‐bond complex, whereas the others are loosely bound. A weak cross peak indicates partial exchange between these excited state subpopulations.
Silyldefluorination of Fluoroarenes by Concerted Nucleophilic Aromatic Substitution
Authors: Mallick Shubhadip , Xu Pan , Würthwein Ernst‐Ulrich , Studer Armido
Published: November 2018

The reaction of readily generated silyl lithium reagents with various aryl fluorides to provide the corresponding aryl silanes is reported. DFT calculations reveal that the nucleophilic aromatic substitution of the fluoride anion by the silyl lithium reagent proceeds through concerted ipso substitution. In contrast to the classical nucleophilic aromatic substitution, this concerted ionic silyldefluorination also occurs on more electron‐rich aryl fluorides.
Guidewire fracture during orbital atherectomy for peripheral artery disease: Insights from the Manufacturer and User Facility Device Experience database
Authors: Isom Nicholas , Masoomi Reza , Thors Axel , Bunte Matthew , Prasad Anand , Hance Kirk , Gupta Kamal
Published: November 2018

Background/Objectives

Orbital atherectomy (OA) is routinely being used for plaque modification to facilitate percutaneous revascularization in patients with peripheral arterial disease (PAD) and arterial calcification. Guidewire fracture (GWF) during OA, though anecdotally described, has not been studied in a systematic manner. We conducted a review of the Manufacturer and User Facility Device Experience (MAUDE) database to study the reports of wire fracture and its management and consequences.

Methods

We queried the MAUDE database for all events involving the current generation of the OA device: “Diamondback 360 Peripheral Orbital Atherectomy System”, and “Stealth 360° Orbital PAD System”.

Results

We identified 62 reports of GWF during OA for PAD. The superficial femoral artery was the most commonly involved atherectomy site. The wire fractured at the soft tip in a majority of cases (68%). Embolized wire fragments were left in the patient in 36 cases (58%), retrieved percutaneously in 10 cases (16%), and trapped by a stent against the arterial wall in eight cases (13%). Lastly, eight patients (13%) underwent surgery for removal of the wire fragment.

Conclusions

This is the first published report to study the complication of GWF during peripheral OA. GWF is an uncommon but has significant procedural and clinical consequences. It results in a high rate of ancillary rescue procedures (including surgery) and is associated with a higher risk of arterial thrombosis and complications from wire retrieval attempts. The risk of wire fracture may be avoided with carefully adherence to the IFU.
Formation of dead zone in catalytic particles in catalysis and biocatalysis—new alternative method of determination
Authors: Król Grzegorz , Szukiewicz Mirosław , Chutkowski Marcin
Published: November 2018

A new alternative method of the determination of necessary conditions for dead zone formation has been proposed. This novel approach is based on simple mathematics and is more intuitive compared to methods that are available in other literature. Its efficiency in the determination of the necessary conditions has been shown for cases that have not yet been discussed as well as in complementary cases that have been taken from solutions from other literature, e.g., for a two‐reagent reaction system, which has been described in detail. Numerical and experimental examples have been given to illustrate the obtained results.
Heterogenous loss of mismatch repair (MMR) protein expression: a challenge for immunohistochemical interpretation and microsatellite instability (MSI) evaluation
Authors: McCarthy Aoife J , Capo‐Chichi Jose‐Mario , Spence Tara , Grenier Sylvie , Stockley Tracy , Kamel‐Reid Suzanne , Serra Stefano , Sabatini Peter , Chetty Runjan
Published: November 2018

Immunohistochemistry (IHC) for mismatch repair (MMR) proteins is used to identify MMR status: being diffusely positive (intact/retained nuclear staining) or showing loss of nuclear tumour staining (MMR protein deficient). Four colonic adenocarcinomas and a gastric adenocarcinoma with associated dysplasia that displayed heterogenous IHC staining patterns in at least one of the four MMR proteins were characterised by next‐generation sequencing (NGS). In order to examine a potential molecular mechanism for these staining patterns, the respective areas were macrodissected, analysed for microsatellite instability (MSI) and investigated by NGS and multiplex ligation‐dependent probe amplification (MLPA) analysis of MLH1, MSH2, MSH6 and PMS2 genes, including MLH1 methylation analysis. One colonic adenocarcinoma showed heterogenous MSH6 IHC staining and molecular analysis demonstrated increasing allelic burden of two MSH6 frameshift variants (c.3261delC and c.3261dupC) in areas with MSH6 protein loss compared to areas where MSH6 was retained. Two colonic adenocarcinomas with heterogenous MLH1 staining showed no differences in sequence variants. In one of these cases, however, MLH1 was hypermethylated in the area of MLH1 loss. Another colon carcinoma with heterogenous PMS2 staining (but with retained MSH6) showed both MSH6 c.3261dupC and 3260_3261dupCC where PMS2 protein was lost and only c.3261dupC where PMS2 was retained. The gastric carcinoma showed complete loss of MSH6 in dysplastic foci, while the underlying invasive carcinoma showed retention of MSH6. Both these areas, however, were MSI‐high and showed the same MSH6 variant: c.3261delC. The gastric dysplasia additionally showed MSH6 c.3261dupC. In four of the five cases where MMR protein was lost, these areas were MSI‐high. Heterogenous MMR IHC (focal and/or zonal within the same tumour or between invasive and dysplastic preinvasive areas) is not always due to artefact and is invariably related to MSI‐high status in the areas of loss. An interesting aspect to this study is the presence of MSH6 somatic mutations irrespective of whether MSH6 IHC staining was intact or lost.
Assessment of Water Quality Improvement Schemes for a Complex River Network: A Case Study of Wenling
Authors: Lin Xichen , Wang Lin , Ni Hongzhen , Chen Genfa , Wang Ying , Wang Jianwei , Liu Siyu
Published: November 2018

Wenling features a high population density, a complex river network, and severe water pollution. Water quality management is impeded by the complex hydrodynamic conditions. In this research, a coupled hydrodynamic and water quality model based on MIKE 11 is developed, and combined pollution control and hydrodynamic optimization schemes are proposed for water quality improvement. The effects of the schemes are evaluated and compared with the water quality model. Comparison of the schemes suggest that pollution control is more effective than hydrodynamic optimization in the Wenling river network. Effective combined schemes that helped to meet the water quality target (class IV) are found. The results suggest that water quality management of Wenling should be focused on both pollution control and hydrodynamic optimization and that pollution control should be prioritized. The contributions of this paper should be valuable for research around the world on the water quality management of complex river network areas such as Wenling.
High‐Throughput Assessment of Mechanistic Toxicity of Chemicals in Miniaturized 3D Cell Culture
Authors: Joshi Pranav , Kang Soo‐Yeon , Datar Akshata , Lee Moo‐Yeal
Published: November 2018

High‐content imaging (HCI) assays on two‐dimensional (2D) cell cultures often do not represent in vivo characteristics accurately, thus reducing the predictability of drug toxicity/efficacy in vivo. On the other hand, conventional 3D cell cultures are relatively low throughput and possess difficulty in cell imaging. To address these limitations, a miniaturized 3D cell culture has been developed on a micropillar/microwell chip platform with human cells encapsulated in biomimetic hydrogels. Model compounds are used to validate human cell microarrays for high‐throughput assessment of mechanistic toxicity. Main mechanisms of toxicity of compounds can be investigated by analyzing multiple parameters such as DNA damage, mitochondrial impairment, intracellular glutathione level, and cell membrane integrity. IC50 values of these parameters can be determined and compared for the compounds to investigate the main mechanism of toxicity. This paper describes miniaturized HCI assays on 3D‐cultured cell microarrays for high‐throughput assessment of mechanistic profiles of compound‐induced toxicity. © 2018 by John Wiley & Sons, Inc.
Highly Active Bifunctional Electrocatalysts for Oxygen Evolution and Reduction in Zn–Air Batteries
Authors: Kim Sung‐Wook , Son Yoonkook , Choi Keunsu , Kim Sun‐I , Son Yeonguk , Park Joohyuk , Lee Jun Hee , Jang Ji‐Hyun
Published: November 2018

To realize the full performance of Zn–air batteries, the co‐presence of a highly efficient oxygen reduction reaction (ORR) and an oxygen evolution reaction (OER) in the system is critical. Although copper and nickel are known to be bifunctional catalysts for ORR and OER, sluggish reactions as a result of the exceptionally strong O=O bond on the metal surface make it difficult to achieve high system efficiency. In this study, a metal carbide layer (CuCx and NiCx) on dendritic copper and nickel is fabricated by a facile electrodeposition process to provide efficient catalytic active sites with moderate binding energy for easy electron transfer in both the OER and the ORR. The dendritic structure provides an enriched catalytic surface and the protective metal carbide layer offers an appropriate O binding energy and durability of Zn–air batteries. Owing to the presence of the stable metal carbide surface on the dendritic metal, the CuCx/Cu and NiCx/Ni catalysts exhibited well‐defined limiting current densities of −5.19 and −5.11 mA cm−2, respectively, and improved ORR and OER activities with lower polarization than the corresponding metal catalysts. Density functional theory revealed a 0.74 eV decrease in the overpotential of NiCx/Ni‐catalyzed OER reactions compared with Ni‐catalyzed OER reactions. The experimental and theoretical results prove that carbide layers on dendritic metal surfaces can greatly improve the activity of ORR and OER bifunctional electrocatalysts for Zn–air batteries.
The First Series of Heterometallic LnIII‐VIV Complexes Based on Substituted Malonic Acid Anions: Synthesis, Structure and Magnetic Properties
Authors: Bazhina Evgeniya S. , Aleksandrov Grigory G. , Kiskin Mikhail A. , Korlyukov Alexander A. , Efimov Nikolay N. , Bogomyakov Artem S. , Starikova Alyona A. , Mironov Vladimir S. , Ugolkova Elena A. , Minin Vadim V. , Sidorov Alexey A. , Eremenko Igor L.
Published: November 2018

The reaction of VOSO4 with K2cbdc (cbdc2– is cyclobutane‐1,1‐dicarboxylate anion) and Ln(NO3)3 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Tm, Yb, Lu) yielded 17 novel heterometallic LnIII‐VIV compounds comprising stable bis‐chelate units {VIVO(cbdc)2(H2O)}. Three structural types of compounds are formed depending on the nature of the rare‐earth metal: 1D polymers {[Ln(VO)(cbdc)2(H2O)7]·0.5[VO(cbdc)2]}n (structural type I) [Ln = La (1), Ce (2)], 3D polymers {[KLn(VO)2(cbdc)4(H2O)9]·3.5H2O}n (structural type II) [Ln = La (3), Ce (4), Pr (5), Nd (6), Sm (7), Eu (8), Gd (9), Tb (10), Dy (11), Ho (12)] comprising trinuclear units {LnV2}, and octanuclear complexes {[KLn(VO)2(cbdc)4(H2O)11]·2H2O}2 (structural type III) [Ln = Y (13), Er (14), Tm (15), Yb (16), Lu (17)] containing dinuclear units {LnV}. Magnetic properties were investigated for all isolated compounds. The GdIII‐VIV compound has ferromagnetic and antiferromagnetic exchange interactions between isotropic VIV and GdIII ions. Calculations using the DFT method at the UB3LYP/6‐31G(d,p)/SDD level of theory were performed in order to explain the different nature of exchange interactions in two GdIII‐VIV pairs. The YbIII‐VIV complex displays single‐molecule magnet properties; the effective energy barrier was estimated at ΔEeff/kB = 26 K. The magnetic properties of LnIII‐VIV compounds with heavy lanthanide ions (LnIII = Er, Tm, Yb) were rationalized in terms of crystal‐field calculations for LnIII ions.
Effect of Sunflower Collets Moisture on Extraction Yield and Oil Quality
Authors: Pérez Ethel E. , Baümler Erica R. , Crapiste Guillermo H. , Carelli Amalia A.
Published: November 2018

The aim of this work is to analyze the effect of moisture content of sunflower expanded material on the quality of the extracted oil by determining its wax, phospholipids, and tocopherol content and composition. Sunflower oil extraction is carried out in a batch extractor at 50 °C using hexane and three moisture levels (5.65, 12.40, and 18.92% dry basis). The increasing moisture content causes an increment in both oil yield and total amount of minor compounds. The total wax content ranges between 808 and 1118 ppm, the wax fraction is composed mainly of esters of between 44 and 58 carbon atoms (>67%), and the distribution does not change with the moisture content. In all the experiments, α‐ and β‐tocopherols and β‐tocotrienol are detected, with the level of α‐tocopherol being higher than 93% and easier to extract at 12.40% moisture. Furthermore, the phospholipids content in the oil increases with moisture content but maintains its profile composition. The obtained results can be explained in terms of water activity and the effect of moisture and hexane extraction on solid structure, studied by scanning electron microscopy. In brief, the moisture content of the collets not only affects the oil yield but also the content of minor compounds, the intermediate moisture rendering the better oil yield and quality.

Practical Applications: The data obtained provides updated information on oil yield and quality associated with moisture content of sunflower collets, useful to select the optimal operating conditions for oil extraction and to establish a trade‐off between performance and quality.

Sunflower collets are conditioned in their moisture content to determine the isotherm sorption and the effects on the oil extraction and quality.
Core‐Shell‐Structured SiOx—C Composite for Lithium‐Ion Battery Anodes
Authors: Zhang Junying , Ma Peipei , Zhang Xiaoming , Liu Zhi , Zheng Jun , Zuo Yuhua , Xue Chunlai , Cheng Buwen , Li Chuanbo
Published: November 2018

A simple method to synthesize a uniform composite material consisting of wet‐milled SiOx core and carbon shell is studied. This SiOx—C core‐shell composite is then used as anode materials for lithium‐ion batteries, with wet‐milled SiOx and raw SiOx anodes used for comparison. It is found that the batteries fabricated with wet‐milled SiOx—C composite show the best cyclic performance and excellent rate capability compared with wet‐milled SiOx and raw SiOx. This approach is beneficial because of the reduced size of wet‐milled SiOx powders. The coating of carbon shell is effective in improving the conductivity of SiOx and diminishing the volume effect during lithiation/delithiation processes. Moreover, the Li2O and Li4SiO4 generated in the first cycle further suppress the volume effects. Under the galvanostatic mode with charging and discharging current density of 0.1 Ag−1, the wet‐milled SiOx—C composite electrode delivers an initial reversible capacity of 1279 mAh g−1, with a capacity retention as high as 97.3% (1244 mAh g−1) even after 170 cycles and coulombic efficiency as high as 99.8%. This approach is simple and has great potential for the large‐scale production of high‐performance SiOx‐based anode materials.
Role of NMDA receptors in the pathophysiology and treatment of status epilepticus
Authors: Kapur Jaideep
Published: November 2018

This review considers the role of N‐methyl‐d‐aspartate receptors in the pathophysiology and treatment of status epilepticus (SE). NMDA receptors play a critical role in sustaining SE by mediating the plasticity of γ‐aminobutyric acid (GABA)‐A and α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) receptors, neuronal loss, and epileptogenesis. In parallel, there is growing interest in using the NMDA receptor antagonist ketamine in the treatment of refractory SE. Ketamine has proved to be safe for use in refractory and super‐refractory SE in patients. The pilot studies also suggest that ketamine may be efficacious for termination of refractory SE.
Liquid biopsies
Authors: Lianidou Evi , Pantel Klaus
Published: November 2018

Liquid biopsy is based on minimally invasive blood tests and has a high potential to significantly change the therapeutic strategy in cancer patients, providing an extremely powerful and reliable noninvasive clinical tool for the individual molecular profiling of patients in real time. Liquid biopsy approaches include the analysis of circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), circulating miRNAs, and tumor‐derived extracellular vesicles (EVs) that are shed from primary tumors and their metastatic sites into peripheral blood. The major advantage of liquid biopsy analysis is that it is minimally invasive, and can be serially repeated, thus allowing extracting information from the tumor in real time. Moreover, the identification of predictive biomarkers in peripheral blood that can monitor response to therapy in real time holds a very strong potential for novel approaches in the therapeutic management of cancer patients. In this review, we summarize recent knowledge on CTCs and ctDNA and discuss future trends in the field.
Specialized neural dynamics for verbal and tonal memory: fMRI evidence in congenital amusia
Authors: Albouy Philippe , Peretz Isabelle , Bermudez Patrick , Zatorre Robert J. , Tillmann Barbara , Caclin Anne
Published: November 2018

Behavioral and neuropsychological studies have suggested that tonal and verbal short‐term memory are supported by specialized neural networks. To date however, neuroimaging investigations have failed to confirm this hypothesis. In this study, we investigated the hypothesis of distinct neural resources for tonal and verbal memory by comparing typical nonmusician listeners to individuals with congenital amusia, who exhibit pitch memory impairments with preserved verbal memory. During fMRI, amusics and matched controls performed delayed‐match‐to‐sample tasks with tones and words and perceptual control tasks with the same stimuli. For tonal maintenance, amusics showed decreased activity in the right auditory cortex, inferior frontal gyrus (IFG) and dorso‐lateral‐prefrontal cortex (DLPFC). Moreover, they exhibited reduced right‐lateralized functional connectivity between the auditory cortex and the IFG during tonal encoding and between the IFG and the DLPFC during tonal maintenance. In contrasts, amusics showed no difference compared with the controls for verbal memory, with activation in the left IFG and left fronto‐temporal connectivity. Critically, we observed a group‐by‐material interaction in right fronto‐temporal regions: while amusics recruited these regions less strongly for tonal memory than verbal memory, control participants showed the reversed pattern (tonal > verbal). By benefitting from the rare condition of amusia, our findings suggest specialized cortical systems for tonal and verbal short‐term memory in the human brain.
Does the insula contribute to emotion‐related distortion of time? A neuropsychological approach
Authors: Mella Nathalie , Bourgeois Alexia , Perren Fabienne , Viaccoz Aurélien , Kliegel Matthias , Picard Fabienne
Published: November 2018

The literature points to a large distributed brain network involved in the estimation of time. Among these regions, the role of the insular cortex is still poorly understood. At the confluence of emotional, interoceptive, and environmental signals, this brain structure has been proposed to underlie awareness of the passage of time and emotion related time dilation. Yet, this assumption has not been tested so far. This study aimed at exploring how a lesion of the insula affects subjective duration, either in an emotional context or in a non‐emotional context. Twenty‐one patients with a stroke affecting the insula, either left or right, were studied for their perception of sub and supra second durations. A verbal estimation task and a temporal bisection task were used with either pure tones or neutral and emotional sounds lasting between 300 and 1500 ms and presented monaurally. Results revealed that patients with a right insular lesion, showed less temporal sensitivity than both control participants and patients with a left insular lesion. Unexpectedly, emotional effects were similar in patients and control participants. Altogether, these results suggest a specific role of the right insula in the discrimination of durations, but not in emotion related temporal distortion. In addition, an ear × emotion interaction in control participants suggests that temporal processing of positive and negative sounds may be lateralized in the brain.
A retrospective study of conscious sedation versus general anaesthesia in patients scheduled for transfemoral aortic valve implantation: A single center experience
Authors: Renner Jochen , Tesdorpf Anna , Freitag‐Wolf Sandra , Francksen Helga , Petzina Rainer , Lutter Georg , Frey Norbert , Frank Derk
Published: November 2018

Objectives

The current 2017 ESC/EACTS guidelines recommend transcatheter aortic valve implantations (TAVIs) as the therapy of choice for inoperable patients with severe symptomatic aortic stenosis. Most of the TAVIs worldwide are performed under general anaesthesia (GA). Although conscious sedation (CS) concepts are increasingly applied in Europe, it is still a matter of debate which concept is associated with highest amount of safety for this high‐risk patient population. The aim of this single center, before‐and‐after study was to investigate feasibility and safety of CS compared with GA with respect to peri‐procedural complications and 30‐day mortality in patients scheduled for transfemoral TAVI (TF‐TAVI).

Methods

From March 2012 until September 2014, patients scheduled for the TF‐TAVI procedure were included in a prospective, observational manner. From the 200 patients finally included, 107 procedures were performed under GA, using either an endotracheal tube or a laryngeal mask, and balanced anaesthesia. CS was performed in 93 patients using low‐dose propofol and remifentanil.

Results

Conversion to GA was needed 4 times due to procedural‐related complications (4.3%), in one patient due to ongoing agitation (1.1%). The CS‐group showed significantly shorter key time courses: anaesthesia time (105 [95‐120] minutes vs 115 [105‐140] minutes, P‐value = 0.009, Mann‐Whitney‐U‐test) and length of stay in the intensive care unit (1.6 [1.0‐1.5] d vs 2.1 [1.0‐2.0] d, P‐value = 0.002, Mann‐Whitney‐U‐test). The lowest mean arterial pressure was significantly higher in the CS‐group compared with the GA‐group (74.3 mmHg vs 55.2 mmHg, P‐value <0.0001, t‐test). CS was associated with less requirements of norepinephrine (0.1 μg/kg vs 2.3 μg/kg, P‐value <0.0001, Mann‐Whitney‐U‐test).

Conclusions

Our single‐center data demonstrate that CS is a feasible and safe alternative, especially with respect to a higher degree of intra‐procedural haemodynamic stability, and a reduced length of stay in the intensive care unit.
Modelling the effects of climatic and hydrological regime changes on the sediment dynamics of the Fraser River Basin, British Columbia, Canada
Authors: Tsuruta Kai , Hassan Marwan A. , Donner Simon D. , Alila Younes
Published: November 2018

Future sediment dynamics may be affected by changing climates or hydrological regimes because of the close link between hydrology and sediment erosion, deposition, and transport. Previously, investigations of these potential changes have been constrained by a combination of limited observational data, hydrological drivers, and appropriate mechanistic models. Additionally, there is often ambiguity regarding how to disentangle the impacts of climate and hydrology from direct human factors such as reservoirs and land‐use change, which often exert more control over sediment dynamics. In this study, we utilize a recently developed, large‐scale, distributed, mechanistic sediment transport model to project future sediment erosion, deposition, and transportation within the Fraser River Basin in British Columbia, Canada—a basin with historical water flux and sediment load observations and limited anthropogenic influences upstream of its delta. The sediment model is driven by synthetic land‐surface hydrology derived from Scenarios A1B, A2, and B1 of the Special Report on Emissions Scenarios, which were provided by the Pacific Climate Impacts Consortium. Resulting simulations of water flux and sediment load from 1965 to 1994 are first validated against observational data then compared with future projections. Future projections show an overall increase in annual hillslope erosion and in‐channel transportation, a shift towards earlier spring peak erosion and transportation, and longer persistence of the sediment signal through the year. These shifts in timing and annual yield may have deleterious effects on spawning sockeye salmon and are insufficient to counteract future coastal retreat caused by sea‐level rise.
The evasiveness conjecture and graphs on vertices
Authors: Ángel Andrés , Borja Jerson
Published: November 2018

The evasiveness conjecture has been proved for properties of graphs on a prime‐power number of vertices and the six‐vertex case. The 10‐vertex case is still unsolved. In this paper we study the size of the automorphism group of a graph on vertices to estimate the Euler characteristic of monotone nonevasive graph properties. We get some conditions on graphs that such graph properties must contain. We also do this by means of Oliver groups and give a new lower bound for the dimension of the simplicial complex associated with a nontrivial monotone nonevasive graph property. We apply our results to graphs on 10 vertices to get conditions on potential counterexamples to the evasiveness conjecture in the 10‐vertex case.
Low expression of pRB predicts disease relapse in early glottic cancer treated with transoral laser microsurgery
Authors: Lee Li‐Ang , Fang Tuan‐Jen , Li Hsueh‐Yu , Huang Chung‐Guei , Chen Tse‐Ching , Liao Chun‐Ta , Kang Chung‐Jan , Chang Kai‐Ping , Yen Tzu‐Chen
Published: November 2018

Objectives/Hypothesis

To elucidate the associations among the immunohistochemical expression of tumor markers, clinicopathological variables, and disease‐free survival (DFS) in patients with early‐stage glottic squamous cell carcinoma (SCC) who underwent transoral laser microsurgery (TLM) as the primary treatment.

Study Design

Retrospective chart review.

Methods

The records of consecutive patients with Tis‒T2N0 glottic SCC who underwent TLM between August 1, 2012 and October 31, 2015 were reviewed. Expression of Bcl‐2, pRB, p16INK4A, p53, c‐Myc, E‐cadherin, and EGFR was examined using tissue microarrays containing tumor specimens through immunohistochemistry. Three‐year DFS rates were calculated.

Results

A total of 65 consecutive patients were identified, of which 28 were excluded due to insufficient tissue (n = 22) and low biomarker quality (n = 6). Therefore, 37 patients with complete records were included. The included patients were significantly older and had a more advanced type of cordectomy than did the excluded patients (P = .015 and .009, respectively). According to the findings of univariate analysis, age, betel quid chewing, type of cordectomy, BCL‐2 expression, and pRB expression significantly predicted 3‐year DFS. According to the findings of multivariate analysis, age (adjusted hazard ratio: 0.94, 95% CI: 0.88‐1.00), betel quid chewing (adjusted hazard ratio: 5.07, 95% CI: 1.32‐19.44), and pRB expression (adjusted hazard ratio: 0.02, 95% CI: 0.00‐0.28) were independent predictors of 3‐year DFS.

Conclusions

Low pRB expression is a potential biomarker for predicting disease relapse after primary TLM for early‐stage glottic SCC and may help to identify high‐risk patients who can subsequently undergo intensive management.

Level of Evidence

4

Laryngoscope, 129:E220–E226, 2019
Effects of trophic status, water level, and temperature on shallow lake metabolism and metabolic balance: A standardized pan‐European mesocosm experiment
Authors: Scharfenberger Ulrike , Jeppesen Erik , Beklioğlu Meryem , Søndergaard Martin , Angeler David G. , Çakıroğlu Ayşe İdil , Drakare Stina , Hejzlar Josef , Mahdy Aldoushy , Papastergiadou Eva , Šorf Michal , Stefanidis Konstantinos , Tuvikene Arvo , Zingel Priit , Adrian Rita
Published: November 2018

Important drivers of gross primary production (GPP) and ecosystem respiration (ER) in lakes are temperature, nutrients, and light availability, which are predicted to be affected by climate change. Little is known about how these three factors jointly influence shallow lakes metabolism and metabolic status as net heterotrophic or autotrophic. We conducted a pan‐European standardized mesocosm experiment covering a temperature gradient from Sweden to Greece to test the differential temperature sensitivity of GPP and ER at two nutrient levels (mesotrophic or eutrophic) crossed with two water levels (1 m and 2 m) to simulate different light regimes. The findings from our experiment were compared with predictions made according the metabolic theory of ecology (MTE). GPP and ER were significantly higher in eutrophic mesocosms than in mesotrophic ones, and in shallow mesocosms compared to deep ones, while nutrient status and depth did not interact. The estimated temperature gains for ER of ~ 0.62 eV were comparable with those predicted by MTE. Temperature sensitivity for GPP was slightly higher than expected ~ 0.54 eV, but when corrected for daylight length, it was more consistent with predictions from MTE ~ 0.31 eV. The threshold temperature for the switch from autotrophy to heterotrophy was lower under mesotrophic (~ 11°C) than eutrophic conditions (~ 20°C). Therefore, despite a lack of significant temperature‐treatment interactions in driving metabolism, the mesocosm's nutrient level proved to be crucial for how much warming a system can tolerate before it switches from net autotrophy to net heterotrophy.
Effects of Interconnected Polymer Nanopores Leading to Different Degrees of Confined Polymerization
Authors: Wang Kui , Lei Jinhua , Nie Heran , Shen Lu , Chen Peng , Zhou Guangyuan
Published: November 2018

In this study, different degrees of ethylene‐confined polymerization (non‐confined, slightly confined, and highly confined) are presented in porous polymer microspheres (PPMs) with an interconnected tri‐modal pore structure. First, three catalysts, Cp2ZrCl2, Cp2TiCl2, and TiCl4, are attached to the interface of PPMs to form a nano‐confined space for ethylene polymerization. Then three types of polyethylene with different degrees of ethylene‐confined polymerization are obtained through polymerization. Results of SEM, BET, FTIR, XPS confirm the existence of the interconnected tri‐modal pore structure in PPMs after catalyst loading, which can provide nanospace for confined polymerization. Typical characteristics of confined polymerization (nanofibers and high molecular weight) are observed through SEM and GPC tests. The results reveal that polyethylene by PPM‐supported TiCl4 is performed as a highly confined reaction and generates microspheres with the highest molecular weight and T
m2. In addition, the product is line polyethylene (PE) regardless of the degrees of confined polymerization. The data of SAXS reveal that high melting point of confined PE is owed to low surface free energy, rather than lamellar thickness in confined space of PPMs. Furthermore, low surface free energy is ascribed to the entanglement of PE chain, which is caused by the interconnected tri‐modal pore structure.
Effect of Blend Composition on Scratch Behavior of Polystyrene/Poly(2,6‐dimethyl‐1,4‐phenyleneoxide) Blends
Authors: Kojio Ken , Kiyoshima Yudai , Kajiwara Tomoko , Higaki Yuji , Sue Hung‐Jue , Takahara Atsushi
Published: November 2018

The relationship between the scratch behavior and molecular aggregation states of polystyrene (PS), poly(2,6‐dimethyl‐1,4‐phenyleneoxide) (PPO), and their blends, is investigated based on differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD), polarized optical microscopy (POM), and indentation and scratch tests. DSC reveals that all the PS/PPO blends show the single glass transition temperature (Tg) and the Tg monotonically increase and Tg breadth exhibits a maximum, with an increase in PPO content. Furthermore, density and intermolecular chain distance obtained by WAXD exhibits maximum and minimum values at near 50 wt% of PPO, respectively. It is evident that densification occurs by blending PS and PPO. The scratch coefficient of friction (SCOF) value of PS is the largest and PS exhibits a fish‐scale pattern after scratch testing, while the SCOF value of PPO is much smaller than PS and PPO exhibits smooth groove formation. The PS50/PPO50 and PS20/PPO80 blends exhibit superior scratch and indentation resistance than PS and PPO. Damage morphology observation by POM and indentation tests reveals that molecular orientation is more restricted, and resistance against indentation increases for blends. This is due mainly to densification of the blend system.
An integrated cascode DE power amplifier for RF calibration system towards measurement of bio‐sensor applications
Authors: Kumar Rajesh , Kanaujia Binod Kumar , Dwari Santanu , Kumar Sandeep , song Hanjung
Published: November 2018

The integrated cascode DE power amplifier for RF calibration system toward measurement of bio‐sensor applications is presented in this paper. The proposed architecture includes cascode class‐D and class‐E amplifier stages that could provide better calibration accuracy in terms of wide bandwidth, power efficiency, high gain, minimum group delay, and lowest calibration system. The achieved high performance of proposed amplifier overcomes conventional measurement issues toward bio‐sensor application. The inductive π‐shape matching network drives RF input to class‐D stage and provides wide bandwidth of operation. While class‐E stage with T‐shape matching network maintains stable gain and high efficiency in desired band of operation. The performance of the CMOS proposed amplifier is executed in RF ADS simulator along with fabricated chip using commercial TSMC 65 nm manufacturing process. The simulated and measured data achieves Ku band (12 GHz to 18 GHz) with almost flat gain of 30 dB. The DE amplifier provides an output and saturated power of 17 dBm with highest power efficiency of 45%. The measured calibration factor at maximum resonant frequency of 13.5 GHz achieves best value of less than 2 dB within input power range of −50 dBm to 0 dBm. The lowest calibration factor provides best accuracy along with the other parameters and could be beneficial toward bio‐sensor measurement in the various applications. The calculated area of the fabricated chip is as 0.45*0.45mm2 where class‐E consuming area of 38% and class‐D of 44%. The fabricated chip consumes less power consumption of 3.2 mW under power supply of 1 V.
Microwave photonics‐based all optical wavelength conversion of Nyquist‐DP‐16QAM for flex‐grid optical networks with 112 Gbps
Authors: Li Guang , Li Jianqing
Published: November 2018

We propose and demonstrate an all optical wavelength conversion of Nyquist differential phase 16 quadrature amplitude modulation based on microwave photonics signal processing for flex‐grid optical networks. By analyzing the mechanism of the microwave photonics and adjusting the parameters of the components, multi‐wavelength tunable laser with smooth and adjustable optical intensity can be obtained. Then, the multi‐channel photonic signals with the minimal guard space of 5 GHz can be obtained, which provide more than 20 flex‐grids for optical transmission with transparent rate and format. The optical power of converted wavelengths, optical signal‐to‐noise ratio, error vector magnitude, and bit error rate (BER) are studied under the condition of different flex‐grids, the frequencies of which are from 15 GHz to 36 GHz. The channel frequency spacing and amplitude of the converted wavelength can be dynamically adjusted via parameter configuration. Flex‐grid spacing strategies and channel selecting strategies are given. The BER performance of all converted channels can fall below the forward error correction threshold of 3.8 × 10−3 by optimizing the optical power of the receiver end. The results show the tradeoff between the BER and the detected optical power of the receiver end. These research findings could provide solutions for spectrum allocation and routing selection when wavelength conversion is needed in optical links.
Novel rat‐race coupler of arbitrary power division design using resonant substrate integrated waveguide cavity
Authors: Hong Wanchu , Hsu Chung‐I G. , Li Jen‐Chih , Ho Min‐Hua
Published: November 2018

The contribution of this letter is to propose a novel rat‐race hybrid coupler of arbitrary power division design. The rat‐race coupler's arbitrary power division design is approached by using a resonant square substrate‐integrated waveguide (SIW) cavity. The employed SIW cavity is operated under the resonance of the combined TE102 and TE201 modes. Due to the nature of the square cavity, these two modes are termed degenerate modes which possess the same resonance frequencies but exhibit distinct field distributions. Theoretically, the cavity can be excited by an arbitrary combination of these two degenerate modes, and each of the modes' power is solitarily extracted by an SMA probe located at an adequate position. The microstrip together with the perpendicularly oriented slot are used to resonate the cavity with a designated combination of the degenerate modes. Sample experiments are conducted on 3 dB and 10 dB coupling designs with the circuits' performance evaluated by the coupling precision, isolations, and phase imbalances.
Dual‐band dual‐sense circularly polarized antenna for S‐ and C‐band applications
Authors: Tran Huy Hung , Le Tuan Tu , Nguyen Truong Khang
Published: November 2018

This paper presents a dual‐band dual‐sense circularly polarized (CP) antenna for S‐ and C‐band applications. A semicircular patch and a circular slot are first designed to achieve wide operation bandwidth in the C‐band with right‐hand CP (RHCP), and then, a curved slot is properly inserted around the circular slot for S‐band realization with left‐hand CP (LHCP). Final antenna prototype has an overall size of 0.32λ
L × 0.32λ
L × 0.01λ
L, where λ
L is free‐space wavelength at the lowest CP frequency. Experimental results show that good CP characteristics for both RHCP and LHCP can be achieved. The measured −10 dB impedance bandwidth is from 2.2 to 6.5 GHz, equivalent to about 98.8%. Additionally, the measured 3 dB axial‐ratio bandwidths for lower and upper bands are, respectively, 4.9% (2.4‐2.52 GHz) and 40.8% (4.0‐6.05 GHz).
Optimization of steady‐state free precession MRI for lung ventilation imaging with 19F C3F8 at 1.5T and 3T
Authors: Maunder Adam , Rao Madhwesha , Robb Fraser , Wild Jim M.
Published: November 2018

Purpose:

To optimize 19F imaging pulse sequences for perfluoropropane (C3F8) gas human lung ventilation MRI considering intrinsic in vivo relaxation parameters at both 1.5T and 3T.

Methods:

Optimization of the imaging parameters for both 3D spoiled gradient (SPGR) and steady‐state free precession (SSFP) 19F imaging sequences with inhaled 79% C3F8% and 21% oxygen was performed. Phantom measurements were used to validate simulations of SNR. In vivo parameter mapping and sequence optimization and comparison was performed by imaging the lungs of a healthy adult volunteer. T1 and T2* mapping was performed in vivo to optimize sequence parameters for in vivo lung MRI. The performance of SSFP and SPGR was then evaluated in vivo at 1.5T and 3T.

Results:

The in vivo T2* of C3F8 was shown to be dependent upon lung inflation level (2.04 ms ± 36% for residual volume and 3.14 ms ± 28% for total lung capacity measured at 3T), with lower T2* observed near the susceptibility interfaces of the diaphragm and around pulmonary blood vessels. Simulation and phantom measurements indicate that a factor of ~2‐3 higher SNR can be achieved with SSFP when compared with optimized SPGR. In vivo lung imaging showed a 1.7 factor of improvement in SNR achieved at 1.5T, while the theoretical improvement at 3T was not attained due to experimental SAR constraints, shorter in vivo T1, and B0 inhomogeneity.

Conclusion:

SSFP imaging provides increased SNR in lung ventilation imaging of C3F8 demonstrated at 1.5T with optimized SSFP similar to the SNR that can be obtained at 3T with optimized SPGR.
Silent T2* and T2 encoding using ZTE combined with BURST
Authors: Schulte Rolf F. , Buonincontri Guido , Costagli Mauro , Menini Anne , Wiesinger Florian , Solana Ana Beatriz
Published: November 2018

Purpose

To obtain T2* and T2‐weighted images as well as quantitative T2*, T2, and susceptibility maps with a novel, silent 3D imaging method, which combines zero‐echo‐time (ZTE) imaging with gradient‐ and spin‐echo BURST encoding.

Methods

After a segment of standard ZTE encoding with multiple 3D radial k‐space spokes, the direction of traversing k‐space is reversed while excitation is switched off. This recalls gradient echoes for each spoke/excitation. This results in multiple images: one FID image from ZTE and multiple BURST echo images at different echo times weighted by a T2* decay. By adding a pair of 180° pulses with an appropriate wait period, it is also possible to obtain spin echoes, leading to T2‐weighted images. Data is reconstructed using standard 3D gridding and Fourier transformation. In vivo feasibility was demonstrated by imaging the brain of multiple healthy volunteers.

Results

It is possible to acquire high‐quality T2*‐ and T2‐weighted brain images in a silent manner. From images acquired with gradient‐echo ZTE‐BURST, it is possible to extract quantitative T2* and magnetic susceptibility maps, whereas the spin echo version yields T2 maps.

Conclusion

ZTE combined with BURST enables silent acquisition of T2*‐ and T2‐weighted images with good image quality.
Cost Effective Surface‐Modified Basalt Fibers‐Reinforced Phthalonitrile Composites With Improved Mechanical Properties and Advanced Nuclear Shielding Efficiency
Authors: Derradji Mehdi , Zegaoui Abdeldjalil , Medjahed Aboubakr , Dayo Abdul Qadeer , Wang Jun , Arse Yitagesu Bereket , Liu Wen‐bin , Liu Yu‐Guang
Published: November 2018

This work relates for the first time ever the use of natural fibers to reinforce the high performance phthalonitrile resins. The excellent thermal stability of the basalt fibers (BFs) allows them to be the only natural fibers resisting the high curing temperatures of the phthalonitrile resins. Based on this promising combination, high performance polymer composites were prepared and their performances were scrutinized in terms of mechanical properties and nuclear shielding efficiency. The BFs which initially underwent a silane surface modification provided materials with metal equivalent tensile and flexural properties. For instance, the composite containing 15 plies of treated fibers achieved the tensile and flexural strengths of 700 and 780 MPa, respectively. Additionally, the same composite stopped 36% of the incident highly ionizing gamma rays. Meanwhile, morphological investigations further confirmed the enhancement seen in the mechanical properties. Overall, the studied composites can be used as advanced materials in extremely exigent applications. POLYM. COMPOS., 40:E912–E919, 2019. © 2018 Society of Plastics Engineers
Thermal cycling influences on compressive deformations of laminate composites
Authors: Ye Junjie , Hong Yun , Wang Yongkun , Shi Baoquan , Zhai Zhi , Chen Xuefeng
Published: November 2018

Composite structures always undergo temperature variations in service. In this procedure, the external loading coupled with thermal cycling will lead to their accelerated failures. In addition, the different loadings and microscopic structural parameters also play the important role in nonlinear deformation behaviors. This article presents a coupled thermo‐mechanical micromechanical model for investigating the compressive deformations of composite laminates with consideration of thermal residual stress. To this end, an effective microscopic model with consideration of coupled thermo‐mechanical behaviors for continuous fiber composites was established. The presented micromechanical method was verified by comparing with experimental data. On this basis, thermal cycling and compressive loading effect on effective deformations of unidirectional lamina composites, as well as laminate composites are both considered. It is indicated that thermal cycling tends to decrease stiffness behaviors first then increase stiffness behaviors under compressive loading. POLYM. COMPOS., 40:2908–2918, 2019. © 2018 Society of Plastics Engineers