bluuebunny/crossref_metadata_2025 huggingface dataset:
Rheological properties and structure of step‐ and chain‐growth gels concentrated above the overlap concentration
Authors: Wehrman Matthew D. , Leduc Andrew , Callahan Holly E. , Mazzeo Michelle S. , Schumm Mark , Schultz Kelly M.
Published: December 2017

Cross‐linked polymeric gels are widely used in applications ranging from biomaterial scaffolds to additives in enhanced oil recovery. Despite this, fundamental understanding of the effect of polymer concentration and reaction mechanism on the scaffold structure is lacking. We measure scaffold properties and structure during gelation using multiple particle tracking microrheology. To determine the effect of concentration, we measure gelation as polymer interactions are increased in the backbone precursor solution: below, at and above the overlap concentration,. To determine structural changes due to the gelation mechanism, we measure gelation between the same polymers undergoing both step‐ and chain‐growth reactions using self‐assembling maleimide:thiol and photo‐initiated acrylate:thiol chemistries, respectively. We determine the critical relaxation exponent, n, a measure of structure. n decreases with increasing concentration, indicating a change from a percolated () to a tightly cross‐linked network (). The gelation mechanism does not have a measurable effect on the scaffold structure. © 2018 American Institute of Chemical EngineersAIChE J, 64: 3168–3176, 2018
Evaluating Food Policy Councils Using Structural Equation Modeling
Authors: Calancie Larissa , Allen Nicole E. , Ng Shu Wen , Weiner Bryan J. , Ward Dianne S. , Ware William B. , Ammerman Alice S.
Published: December 2017

At least 282 Food Policy Councils (FPCs) are currently working to improve access to healthy foods in their communities by connecting food system sectors, gathering community input, and advising food policy. Empirical research on FPCs is limited. This study empirically evaluates FPCs to better understand the relationships between Organizational Capacity, Social Capital, and Council Effectiveness by testing a FPC Framework adapted from Allen and colleagues (2012). Members of all FPCs in the U.S., Canada, and Native American Tribes and First Nations were invited to complete the Food Policy Council Self‐Assessment Tool (FPC‐SAT). Structural equation modeling was used to test the FPC Framework. Three hundred and fifty‐four FPC members from 95 councils completed the FPC‐SAT. After slight modification, a revised FPC Framework was a good fit with the data (χ2 = 40.085, df = 24, p‐value = .021, comparative fit index = 0.988, Tucker Lewis index = 0.982, root mean squared error of approximation = 0.044, p‐close = .650). A moderation analysis revealed that community context influences the relationship between Social Capital and Council Effectiveness within the FPC Framework. The FPC Framework can guide capacity building interventions and FPC evaluations. The empirically tested framework can help FPCs efficiently work toward achieving their missions and improving their local food system.
Highlighting the Way Forward: A Review of Community Mental Health Research and Practice Published in AJCP and JCP
Authors: Townley Greg , Terry Rachel
Published: December 2017

Articles published in the two most prominent journals of community psychology in North America, the American Journal of Community Psychology (AJCP) and Journal of Community Psychology (JCP), provide a clear indicator of trends in community research and practice. An examination of community psychology's history and scholarship suggests that the field has reduced its emphasis on promoting mental health, well‐being, and liberation of individuals with serious mental illnesses over the past several decades. To further investigate this claim, the current review presents an analysis of articles relevant to community mental health (N = 307) published in the American Journal of Community Psychology (AJCP) and Journal of Community Psychology (JCP) from 1973 to 2015. The review focuses on article characteristics (e.g., type of article and methods employed), author characteristics, topic areas, and theoretical frameworks. Results document a downward trend in published articles from the mid‐1980s to mid‐2000s, with a substantial increase in published work between 2006 and 2015. A majority of articles were empirical and employed quantitative methods. The most frequent topic area was community mental health centers and services (n = 49), but the past three decades demonstrate a clear shift away from mental health service provision to address pressing social issues that impact community mental health, particularly homelessness (n = 42) and community integration of adults with serious mental illnesses (n = 40). Findings reflect both the past and present state of community psychology and suggest promising directions for re‐engaging with community mental health and fostering well‐being, inclusion, and liberation of adults experiencing serious mental health challenges.
A Zeolite Family Nonjointly Built from the 1,3‐Stellated Cubic Building Unit
Authors: Jo Donghui , Park Gi Tae , Shin Jiho , Hong Suk Bong
Published: December 2017

From a technological point of view, the synthesis of new high‐silica zeolites is of prime importance owing to their high potential as industrial catalysts and catalyst supports. Two such materials have been synthesized which are made up of the 1,3‐stellated cubic unit (hexahedral ([4254]) bre unit) as a secondary building unit, with the aid of existing imidazolium‐based structure‐directing agents under “excess fluoride” conditions. One of them, denoted PST‐21, is the first aluminosilicate zeolite consisting of 9‐ring apertures solely; it displays exceptional activity towards steering the skeletal isomerization of 1‐butene to isobutene and bridges the gap between small‐ and medium‐pore structures. A series of hypothetical structures are also described that are nonjointly built from the bre unit; all of these structures are chemically feasible and will thus be helpful in designing the synthesis of novel zeolites containing 9‐ring and/or 10‐ring channels.
Synthesis and Structure Revision of Dichrocephones A and B
Authors: Schmiedel Volker M. , Hong Young J. , Lentz Dieter , Tantillo Dean J. , Christmann Mathias
Published: December 2017

Herein, we report the first enantioselective synthesis of dichrocephones A and B, which are cytotoxic triquinane sesquiterpenes with a dense array of stereogenic centers within a strained polycyclic environment. Key features include the application of a catalytic asymmetric Wittig reaction, followed by stereoselective functionalization of the propellane core into a pentacyclic intermediate. Double reductive ring cleavage yielded the proposed structure of dichrocephone A. Mismatched spectroscopic data for our synthetic material compared to the natural isolate led us to revise the previously proposed configuration based on biosynthetic considerations and NMR calculations. Implementation of these findings culminated in the synthesis of dichrocephones A and B.
Modeling the viscoelasticity of polyetherimide
Authors: Wu Qi , Ogasawara Tomotaka , Yoshikawa Nobuhiro , Zhai Hongzhou
Published: December 2017

Viscoelasticity is a mechanical phenomenon where the material modulus varies with time and temperature. Modern experimental methods can determine material properties within certain time and temperature ranges, but modeling the viscoelastic behavior remains challenging, mainly because the data processing is complex and different materials have distinct properties. Using polyetherimide as an example and based on the change in the secondary bonds of polyetherimide in different viscoelastic stages, we proposed a new shift factor model in Arrhenius format with alterable activation energy. We also used two methods based on nonlinear least squares to obtain the Maxwell model of the polyetherimide, and we then used a novel method integrated with Laplace transforms and partial fraction decomposition to convert the Maxwell model into the Voigt model. The results of our model are reliable and self‐consistent, showing its potential for modeling the viscoelasticity of other materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46102.
Tetraacylgermanes as highly efficient photoinitiators for visible light cured dimethacrylate resins and dental composites
Authors: Moszner Norbert , Fischer Urs Karl , Lamparth Iris , Fässler Pascal , Radebner Judith , Eibel Anna , Haas Michael , Gescheidt Georg , Stueger Harald
Published: December 2017

Tetrabenzoylgermane1and various substituted tetrabenzoylgermanes2–7were investigated as visible light (VL) photoinitiators (PIs) for dental dimethacrylate resins and dimethacrylate‐based composites. The tetrabenzoylgermanes1–7show a very strong VL absorption between 400 and 450 nm. Substituents on the benzoyl chromophore strongly influence their properties such as melting point, solubility, absorption behavior, or PI reactivity. A good photobleaching behavior and a very high reactivity as VL PI was found in photo‐differential scanning calorimeter experiments for selected tetrabenzoylgermanes. Composite pastes containing only ∼0.1 wt % of Ge‐PI exhibited a sufficient photocuring due to the high PI‐reactivity of the tetraacylgermanes. Among the investigated germane PIs, tetrakis(2‐methylbenzoyl)germane2shows the best performance as VL PI for restorative composites and enables the composites to be photocured using an LED with an emission maximum of 500 nm. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2018,135, 46115.
Comparative study of gamma and ion beam irradiation of polymeric nanocomposite on electrical conductivity
Authors: Lotfy S. , Atta A. , Abdeltwab E.
Published: December 2017

Poly(vinyl alcohol) (PVA) was used to prepare nanocomposites of multi‐wall carbon nanotubes (MWCNT) and functionalized carbon nanotubes (MWCNT‐NH2) in existence of 2‐carboxyethyl acrylate oligomers (CEA). Radiation‐induced crosslinking of the prepared matrix was carried out via gamma and ion beam irradiation. A comparative study of gamma and ion beam irradiation effect on the electrical conductivity of nanocomposite was conducted. The gelation of the gamma irradiated matrix outperforms the ion beam irradiated matrix. The order of gelation is PVA > (PVA/CEA) > (PVA/CEA)‐MWCNT > (PVA/CEA)‐MWCNT‐NH2. There is a significant reduction in the swelling of the nanocomposite. The formation of nanocomposites was confirmed by scanning electron microscopy, energy‐dispersive X‐ray (EDX) and FTIR examinations. The direct current electrical properties of PVA/nanocomposites are examined at room temperature by applying electric voltage from 1 to 20 V. The results revealed that the electrical conductivity is increased by adding the carbon nanotubes and irradiation by gamma and ion beam. At an applied electric voltage 20 V, in the electrical conductivity of the unirradiated PVA was from 9.20 × 10−8 S cm−1. After adding MWCNT an increase up to 4.70 × 10−5 S cm−1 was observed. While after ion beam irradiation, a further increase up to 9.30 × 10−5 S cm−1 was noticed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46146.
A longitudinal study in learning preferences and academic performance in first year medical school
Authors: Hu Yenya , Gao Hong , Wofford Marcia M. , Violato Claudio
Published: December 2017

This is a longitudinal study of first year medical students that investigates the relationship between the pattern change of the learning preferences and academic performance. Using the visual, auditory, reading‐writing, and kinesthetic inventory at the beginning of the first and second year for the same class, it was found that within the first year, 36% of the class remained unimodal (single) modality learners (SS), 14% changed from unimodal to multimodality learners (SM), 27% changed from multimodality to unimodal modality learners (MS) and 21% remained as multimodality learners (MM). Among the academic performance through subsequent didactic blocks from Clinical Anatomy, Cell and Subcellular Processes to Medical Neuroscience during first year, the SM group made more significant improvement compared to the SS group. Semi‐structured interview results from the SM group showed that students made this transition between the Clinical Anatomy course and the middle of the Medical Neuroscience course, in an effort to improve their performance. This study suggests that the transition from unimodal to multimodality learning among academically struggling students improved their academic performance in the first year of medical school. Therefore, this may be considered as part of academic advising tools for struggling students to improve their academic performances. Anat Sci Educ 11: 488–495. © 2017 American Association of Anatomists.
Pulsed electromagnetic field improves subchondral bone microstructure in knee osteoarthritis rats through a Wnt/β‐catenin signaling‐associated mechanism
Authors: Yang Xiaotian , He Hongchen , Gao Qiang , He Chengqi
Published: December 2017

Pulsed electromagnetic field (PEMF) is often used for management of osteoarthritis (OA). The aim of the study was to determine whether PEMF can successfully improve subchondral bone microstructure through a Wnt/β‐catenin signaling‐associated pathway in rats with knee OA induced by low‐dose monosodium iodoacetate (MIA). Seventy‐two 12‐week‐old male Sprague–Dawley rats were randomly assigned to three groups: OA (n = 24), PEMF (n = 24), and Control (n = 24). OA was induced (OA and PEMF groups) by injecting 0.2 mg MIA in rats’ right knee joint. The control rats received a single sterile saline injection in the right knee. Rats in the PEMF group were exposed to daily 2 h PEMF exposure with 75 Hz, 1.6 mT for 4 weeks. After 4 weeks, micro‐computed tomography (micro‐CT), real‐time PCR, and immunohistochemistry staining were performed. The PEMF group increased bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), and suppressed bone surface/bone volume (BS/BV) and trabecular separation (Tb.Sp) levels in micro‐CT analysis. Real‐time PCR analysis showed that PEMF promoted tibial subchondral bone's gene expressions of Wnt3a, β‐catenin, and OPG, but did not alter LRP5 and RANKL mRNA levels. Similar results involved tibial subchondral bone's protein expressions that were observed in immunohistochemistry staining. These results suggest that PEMF preserved the structural integrity of subchondral bone in knee OA rats by promoting the activation of Wnt/β‐catenin signaling and OPG/RANKL/RANK signaling. Bioelectromagnetics. 39:89–97, 2018. © 2017 Wiley Periodicals, Inc.
Exploration of interaction of canthaxanthin with human serum albumin by spectroscopic and molecular simulation methods
Authors: Jia Jie , Wang Yuxian , Liu Yueying , Xiang Yuhong
Published: December 2017

The interaction between the food colorant canthaxanthin (CA) and human serum albumin (HSA) in aqueous solution was explored by using fluorescence spectroscopy, three‐dimensional fluorescence spectra, synchronous fluorescence spectra, UV–vis absorbance spectroscopy, circular dichroism (CD) spectra and molecular docking methods. The thermodynamic parameters calculated from fluorescence spectra data showed that CA could result in the HSA fluorescence quenching. From the KSV change with the temperature dependence, it was concluded that HSA fluorescence quenching triggered by CA is the static quenching and the number of binding sites is one. Furthermore, the secondary structure of HSA was changed with the addition of CA based on the results of synchronous fluorescence, three‐dimensional fluorescence and CD spectra. Hydrogen bonds and van der Waals forces played key roles in the binding process of CA with HSA, which can be obtained from negative standard enthalpy (ΔH) and negative standard entropy (ΔS). Furthermore, the conclusions were certified by molecular docking studies and the binding mode was further analyzed with Discovery Studio. These conclusions can highlight the potential of the interaction mechanism of food additives and HSA.
Engineered cell migration to lesions linked to autoimmune disease
Authors: Mosabbir Abdullah Al , Qudrat Anam , Truong Kevin
Published: December 2017

The damaging and degenerative effects in autoimmune diseases such as rheumatoid arthritis, multiple sclerosis and Crohn's disease often manifests as the formation of lesions that feature a high local concentration of granulocyte–macrophage colony‐stimulating factor (GM‐CSF). GM‐CSF along with other pro‐inflammatory factors form a positive feedback loop that ultimately perpetuate the lesions. Hence, to engineer chemotaxis to GM‐CSF, we created a new chimeric GM‐CSF receptor alpha subunit (GMRchi) that was coupled with a previously engineered Ca2+‐activated RhoA. When these proteins were expressed in mammalian cells, it allowed migration to chemical and cellular sources of GM‐CSF. As a possible therapeutic intervention, we further implemented the mechanism of cell–cell membrane fusion and subsequent death. Since the microenvironment of lesions is more than just GM‐CSF secretion, the further ability to recognize a combination of other features such as tissue markers will be needed for greater specificity. Nonetheless, this work represents a first step to enable cell‐based therapy of autoimmune lesions.
Feedback from human posterior parietal cortex enables visuospatial category representations as early as primary visual cortex
Authors: Li Yanyan , Hu Xiaopeng , Yu Yongqiang , Zhao Ke , Saalmann Yuri B. , Wang Liang
Published: December 2017

Introduction

Categorization is a fundamental cognitive process, whereby the brain assigns meaning to sensory stimuli. Previous studies have found category representations in prefrontal cortex and posterior parietal cortex (PPC). However, these higher‐order areas lack the fine‐scale spatial representations of early sensory areas, and it remains unclear what mechanisms enable flexible categorization based on fine‐scale features.

Methods

In this study, we decoded functional MRI signals and measured causal influences, across visual, parietal, and prefrontal cortex from participants performing categorization based on coarse‐ or fine‐scale spatial information in thirteen healthy adults.

Results

We show that category information based on coarse discriminations was represented in the PPC, in the intraparietal sulcus region, IPS1/2, at an early stage of categorization trials, whereas representations of category information based on fine‐scale discriminations formed later during interactions between IPS1/2 and primary visual cortex (V1). Specifically, when fine‐scale discriminations were necessary, we decoded significant category information from V1 at an intermediate stage of trials and again from IPS1/2 at a late stage. IPS1/2 feedback was critical, because categorization performance improved as causal influence from IPS1/2 to V1 increased. Further, these mechanisms were plastic, as the selectivity of IPS1/2 and V1 responses shifted markedly with retraining to categorize the same stimuli into two new groups.

Conclusions

Our findings suggest that reentrant processing between the PPC and visual cortex enables flexible abstraction of category information.
Food‐related salience processing in healthy subjects during word recognition: Fronto‐parietal network activation as revealed by independent component analysis
Authors: Safi Annette , Nikendei Christoph , Terhoeven Valentin , Weisbrod Matthias , Sharma Anuradha
Published: December 2017

Background

The study aimed to isolate and localize mutually independent cognitive processes evoked during a word recognition task involving food‐related and food‐neutral words using independent component analysis (ICA) for continuously recorded EEG data. Recognition memory (old/new effect) involves cognitive subcomponents—familiarity and recollection—which may be temporally and spatially dissociated in the brain. Food words may evoke additional attentional salience which may interact with the old/new effect.

Methods

Sixteen satiated female participants undertook a word recognition task consisting of an encoding phase (learning of presented words, 40 food‐related and 40 food neutral) and a test phase (recognition of previously learned words and new words). Simultaneously recorded 64‐channel EEG data were decomposed into mutually independent components using the Infomax algorithm in EEGLAB. The components were localized using single dipole fitting using a four‐shell BESA head model. The resulting (nonartefactual) components with <15% residual variance were clustered across subjects using the kmeans algorithm resulting in five meaningful clusters localized to fronto‐parietal regions. Repeated‐measures anova was employed to test main effects (old/new and food relevance) and their interaction on cluster time courses.

Results

Early task‐relevant old/new effects were localized to the medial frontal gyrus (MFG) and later old/new effects to the right parietal regions (precuneus). Food‐related (nontask‐relevant) salience effects were localized to bilateral parietal regions (left precuneus and right postcentral gyrus). Food‐related salience interacted with task relevance, the old/new effect in MFG being significant only for food‐neutral words highlighting central the role of MFG as the converging site of endogenous and exogenous salience inputs.

Conclusion

Our results indicate ICA to be a valid technique to decompose complex neurophysiological signals involving multiple cognitive processes and implicate the fronto‐parietal network as an important attentional network for processing salience and task demands.
Longitudinal evaluation of Tau‐P301L transgenic mice reveals no cognitive impairments at 17 months of age
Authors: Kent Brianne A. , Heath Christopher J. , Kim Chi Hun , Ahrens Rosemary , Fraser Paul E. , St George‐Hyslop Peter , Bussey Timothy J. , Saksida Lisa M.
Published: December 2017

Introduction

Tau is a microtubule‐associated binding protein implicated in neurodegenerative tauopathies, including frontotemporal dementia (FTD) and Alzheimer's disease (AD). These diseases result in the intracellular accumulation of hyperphosphorylated tau in the form of neurofibrillary tangles, the presence of which is associated with cognitive deficits.

Methods

We conducted a longitudinal behavioral study to provide a profile of the TgTau(P301L)23027 transgenic mouse in multiple cognitive domains across multiple ages. P301L is the tau mutation most frequently observed in patients with frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP‐17) and this mouse model recapitulates the progressive development of glial and neurofibrillary tangles, and associated cerebral atrophy observed in patients. We examined frontal cortex‐dependent executive function and attention with the touchscreen 5‐choice serial reaction time test (5‐CSRTT) and assessed the function of temporal cortical structures using novel object recognition (OR).

Results

Despite using sensitive tasks, there were no apparent changes in executive function, attention, or recognition memory in the transgenic mice from 5 to 17 months of age.

Conclusions

This study represents the first comprehensive longitudinal analysis of cognition in the TgTauP301L mouse model and suggests that this model is not ideal for studying early attention and recognition memory impairments associated with tauopathy. However, spatial and object recognition memory impairments were observed during follow‐up assessments when the mice were 18 and 21 months, respectively. These impairments are consistent with previous publications, and with a dementia‐like phenotype in these mice when aged.
NMR Spectroscopic Isotope Tracking Reveals Cascade Steps in Carbohydrate Conversion by Tin‐Beta
Authors: Elliot Samuel G. , Taarning Esben , Madsen Robert , Meier Sebastian
Published: December 2017

Quantitative isotope tracking studies were used to investigate the reaction pathways that occur for Sn‐Beta‐catalyzed carbohydrate conversion to various α‐hydroxy esters. Experimental insight into the conversion of pentoses was sought (i) by identifying pathways based on isotope patterns in the reaction products and (ii) by probing asymmetric isotope incorporation into products. The results indicate that reaction intermediates remain coordinated to the active site throughout the reaction cascades, regardless of the reaction pathway. A predominant transformation of the C1 carbohydrate position to the C3 position of methyl lactate resembles enzymatic glycolysis. Likewise, the majority of retro‐aldol cleavage occurs from the carbohydrate in the ketose form, which again resembles biological glycolysis. In addition, various side‐activities are detected in Sn‐Beta‐catalyzed carbohydrate conversion, which include 5,1‐hydride and 1,2‐carbon shift of the carbohydrates.
Hydroconversion of Waste Cooking Oil into Bio‐Jet Fuel over a Hierarchical NiMo/USY@Al‐SBA‐15 Zeolite
Authors: Zhang Zongwei , Wang Qingfa , Chen Hao , Zhang Xiangwen
Published: December 2017

The direct conversion of waste cooking oil (WCO) into bio‐jet fuel was investigated over a core‐shell hierarchical USY@Al‐SBA‐15 zeolite‐supported NiMo catalyst. The core‐shell structure showed better acid and pore size distributions. The synergetic effect of the core‐shell micropore and mesopore structure significantly contributed to enhancing the selectivity for the jet fuel (C9–15 hydrocarbons) from 9.3 % over NiMo/USY up to 35.7 % over NiMo/USY@Al‐SBA‐15, with high isomerization (iso‐/n‐paraffins ratio = 2.7) and moderate aromatic fraction (18.7 %). The decarboxylation reaction was selectively enhanced. Optimal selectivity for jet fuel (39.7 %) was obtained at 380 °C and a high H2/oil ratio would decrease the yield of jet fuel. This catalyst showed excellent stability for the hydroconversion of WCO to hydrocarbons.
Photoredox‐Switchable Resorcin[4]arene Cavitands: Radical Control of Molecular Gripping Machinery via Hydrogen Bonding
Authors: Milić Jovana , Zalibera Michal , Talaat Darius , Nomrowski Julia , Trapp Nils , Ruhlmann Laurent , Boudon Corinne , Wenger Oliver S. , Savitsky Anton , Lubitz Wolfgang , Diederich François
Published: December 2017

Semiquinones (SQ) are generated in photosynthetic organisms upon photoinduced electron transfer to quinones (Q). They are stabilized by hydrogen bonding (HB) with the neighboring residues, which alters the properties of the reaction center. We designed, synthesized, and investigated resorcin[4]arene cavitands inspired by this function of SQ in natural photosynthesis. Cavitands were equipped with alternating quinone and quinoxaline walls bearing hydrogen bond donor groups (HBD). Different HBD were analyzed that mimic natural amino acids, such as imidazole and indole, along with their analogues, pyrrole and pyrazole. Pyrroles were identified as the most promising candidates that enabled the cavitands to remain open in the Q state until strengthening of HB upon reduction to the paramagnetic SQ radical anion provided stabilization of the closed form. The SQ state was generated electrochemically and photochemically, whereas properties were studied by UV/Vis spectroelectrochemistry, transient absorption, and EPR spectroscopy. This study demonstrates a photoredox‐controlled conformational switch towards a new generation of molecular grippers.
Stiction detection in low sampling rate signals
Authors: Dambros Jônathan W. V. , Farenzena Marcelo , Trierweiler Jorge O.
Published: December 2017

It is a consensus that stiction brings strong oscillations for chemical plants and its automatic detection still needs efforts to be fulfilled. Despite the large number, no stiction detection method covers with confidence all cases found industrially. Conditions such as strong noise presence, disturbance, or low sampling may lead to misclassification of the oscillation cause. In this work, a technique for dealing with low sampling signals is introduced. The technique is based on grouping different periods of the signal in such a way that the resulting signal exhibits a higher number of data per cycle and can be analyzed by conventional stiction detection methods. The technique is applied to simulated and industrial data. Results demonstrate the best detection performance after the application of the proposed technique, where stiction detection becomes virtually independent of the sampling period.
Biomarker discovery for renal cancer stem cells
Authors: Corrò Claudia , Moch Holger
Published: December 2017

Characterised by high intra‐ and inter‐tumor heterogeneity, metastatic renal cell carcinoma (RCC) is resistant to chemo‐ and radiotherapy. Therefore, the development of new prognostic and diagnostic markers for RCC patients is needed. Cancer stem cells (CSCs) are a small population of neoplastic cells within a tumor which present characteristics reminiscent of normal stem cells. CSCs are characterised by unlimited cell division, maintenance of the stem cell pool (self‐renewal), and capability to give rise to all cell types within a tumor; and contribute to metastasis in vivo (tumourigenicity), treatment resistance and recurrence. So far, many studies have tried to establish unique biomarkers to identify CSC populations in RCC. At the same time, different approaches have been developed with the aim to isolate CSCs. Consequently, several markers were found to be specifically expressed in CSCs and cancer stem‐like cells derived from RCC such as CD105, ALDH1, OCT4, CD133, and CXCR4. However, the contribution of genetic and epigenetic mechanisms, and tumor microenvironment, to cellular plasticity have made the discovery of unique biomarkers a very difficult task. In fact, contrasting results regarding the applicability of such markers to the isolation of renal CSCs have been reported in the literature. Therefore, a better understanding of the mechanism underlying CSC may help dissecting tumor heterogeneity and drug treatment efficiency.
Effect of Material Structure on Photoluminescence of ZnO/MgO Core‐Shell Nanowires
Authors: Marvinney Claire E. , Shen Xiao , McBride James R. , Critchlow Dominic , Li Zhineng , Mayo Daniel C. , Mu Richard R. , Pantelides Sokrates T. , Haglund Richard F.
Published: December 2017

Zinc oxide (ZnO) nanowires are widely studied for use in ultraviolet optoelectronic devices, such as nanolasers and sensors. Nanowires (NWs) with an MgO shell exhibit enhanced band‐edge photoluminescence (PL), a result previously attributed to passivation of ZnO defects. However, we find that processing the ZnO NWs under low oxygen partial pressure leads to an MgO‐thickness‐dependent PL enhancement owing to the formation of optical cavity modes. Conversely, processing under higher oxygen partial pressure leads to NWs that support neither mode formation nor band‐edge PL enhancement. High‐resolution electron microscopy and density‐functional calculations implicate the ZnO m‐plane surface morphology as the key determinant of core‐shell structure and cavity‐mode optics. A ZnO surface with atomic steps along the m‐plane in the c‐axis direction stimulates the growth of a smooth MgO shell that supports guided‐wave optical modes and enhanced UV PL. On the other hand, a smoother ZnO surface leads to nucleation of a rough cladding layer which supports neither enhanced UV PL nor optical cavity modes. Finite‐element analysis shows a clear correlation between allowed Fabry‐Perot and whispering gallery modes and enhanced UV‐PL. These results point the way to fabricating ZnO/MgO core‐shell nanowires for more efficient UV nanolasers, scintillators, and sensors.
Honeycomb Schrödinger Operators in the Strong Binding Regime
Authors: Fefferman Charles L. , Lee‐Thorp James P. , Weinstein Michael I.
Published: December 2017

In this article, we study the Schrödinger operator for a large class of periodic potentials with the symmetry of a hexagonal tiling of the plane. The potentials we consider are superpositions of localized potential wells, centered on the vertices of a regular honeycomb structure corresponding to the single electron model of graphene and its artificial analogues. We consider this Schrödinger operator in the regime of strong binding, where the depth of the potential wells is large. Our main result is that for sufficiently deep potentials, the lowest two Floquet‐Bloch dispersion surfaces, when appropriately rescaled, converge uniformly to those of the two‐band tight‐binding model (Wallace, 1947 [56]). Furthermore, we establish as corollaries, in the regime of strong binding, results on (a) the existence of spectral gaps for honeycomb potentials that break 𝒫𝒯 symmetry and (b) the existence of topologically protected edge states—states that propagate parallel to and are localized transverse to a line defect or “edge”—for a large class of rational edges, and that are robust to a class of large transverse‐localized perturbations of the edge. We believe that the ideas of this article may be applicable in other settings for which a tight‐binding model emerges in an extreme parameter limit.© 2017 Wiley Periodicals, Inc.
Modeling local adaptation and gene flow in sockeye salmon
Authors: Lin Jocelyn E. , Hard Jeffrey J. , Hilborn Ray , Hauser Lorenz
Published: December 2017

Microevolutionary processes determine levels of local adaptation within populations and presumably affect population productivity, but selection and phenotypic evolution have not often been linked explicitly to population dynamics in the wild. Here, we describe a stochastic, individual‐based model that simulates evolutionary and demographic effects of migration and selection in interconnected sockeye salmon populations. Two populations were simulated based on parameters obtained empirically from wild populations in the Bristol Bay region of southwestern Alaska, representing beach‐ and stream‐spawning ecotypes. Individuals underwent a full salmonid life cycle, experiencing sexual selection, size‐selective harvest, and predation based on body size at maturity. Stabilizing natural selection on the three traits (body length, body depth, and age at maturity) tracked for all individuals favored different phenotypes in the two ecotype populations, and the three traits evolved in a genetically correlated manner. Simulation results showed that stabilizing selection on fish phenotypes was always critical for maintaining local adaptation, especially when dispersal rates were high, but loss of local adaptation did not result in substantial loss of productivity. Rather, productivity was more strongly influenced by the opposing effects of stabilizing and harvest selection; strong stabilizing selection caused the salmon to evolve larger body sizes that made them more likely to be caught in the fishery. The model results suggest that interactions between different selection pressures can have substantial demographic as well as evolutionary consequences in wild salmon populations, with key implications for sustainability of natural production in the face of selective harvest and systemic environmental change.
Acutely decompensated heart failure with preserved and reduced ejection fraction present with comparable haemodynamic congestion
Authors: Van Aelst Lucas N.L. , Arrigo Mattia , Placido Rui , Akiyama Eiichi , Girerd Nicolas , Zannad Faiez , Manivet Philippe , Rossignol Patrick , Badoz Marc , Sadoune Malha , Launay Jean‐Marie , Gayat Etienne , Lam Carolyn S.P. , Cohen‐Solal Alain , Mebazaa Alexandre , Seronde Marie‐France
Published: December 2017

Aims

Congestion is a central feature of acute heart failure (HF) and its assessment is important for clinical decisions (e.g. tailoring decongestive treatments). It remains uncertain whether patients with acute HF with preserved ejection fraction (HFpEF) are comparably congested as in acute HF with reduced EF (HFrEF). This study assessed congestion, right ventricular (RV) and renal dysfunction in acute HFpEF, HFrEF and non‐cardiac dyspnoea.

Methods and results

We compared echocardiographic and circulating biomarkers of congestion in 146 patients from the MEDIA‐DHF study: 101 with acute HF (38 HFpEF, 41 HFrEF, 22 HF with mid‐range ejection fraction) and 45 with non‐cardiac dyspnoea. Compared with non‐cardiac dyspnoea, patients with acute HF had larger left and right atria, higher E/e', pulmonary artery systolic pressure and inferior vena cava (IVC) diameter at rest, and lower IVC variability (all P < 0.05). Mid‐regional pro‐atrial natriuretic peptide (MR‐proANP) and soluble CD146 (sCD146), but not B‐type natriuretic peptide (BNP), correlated with echocardiographic markers of venous congestion. Despite a lower BNP level, patients with HFpEF had similar evidence of venous congestion (enlarged IVC, left and right atria), RV dysfunction (tricuspid annular plane systolic excursion), elevated MR‐proANP and sCD146, and renal impairment (estimated glomerular filtration rate; all P > 0.05) compared with HFrEF.

Conclusion

In acute conditions, HFpEF and HFrEF presented in a comparable state of venous congestion, with similarly altered RV and kidney function, despite higher BNP in HFrEF.
The Rich Chemistry Resulting from the 1,3‐Dipolar Cycloaddition Reactions of Enamines and Azides
Authors: Bakulev Vasiliy A. , Beryozkina Tetyana , Thomas Joice , Dehaen Wim
Published: December 2017

Enamines exhibit exceptionally high reactivity in their 1,3‐dipolar cycloaddition reactions with azides in comparison with other dipolarophiles. This review includes the reactions of various types of enamines with azides of different nature, including catalytic processes. The initial products of the reaction, 1,2,3‐triazolines, are generally unstable and very reactive compounds which are prone to undergo various ring transformations. This provides the background for new synthetic methods and novel reaction types. The formation of a variety of products derived from the reaction of enamines with azides such as mono‐, di‐and tri‐substituted 1,2,3‐triazoles, including N‐unsubstituted derivatives, fused, conjugated and spiro heterocycles, two types of amidines and diaminoalkenes are classified in this review according to the type of stabilization/transformation of the intermediate triazolines.
Monoprotection of Arylene‐Diacetic Acids Allowing the Build‐Up of Longer Aromatic Ribbons by Successive Perkin Condensations
Authors: Naulet Guillaume , Robert Antoine , Dechambenoit Pierre , Bock Harald , Durola Fabien
Published: December 2017

Aryl diacetic mono‐acid mono‐esters were designed and efficiently synthesized as mono‐protected bifunctional building blocks for the Perkin condensation between arylacetic acids and arylglyoxylic acids. Although, so far, this Perkin strategy has only been used for the formation of linear trimers or macrocyclic tetramers, it can now be adapted to the formation of pentameric conjugated species to give access, after adequate intramolecular cyclizations, to longer and more complex carboxy‐substituted polycyclic aromatic compounds.
Voltammetric Characterisation of Anticancer Drug Irinotecan
Authors: Novak Jovanović Ivana , Komorsky‐Lovrić Šebojka , Lucić Vrdoljak Ana , Popović Aleksandar R. , Neuberg Marijana
Published: December 2017

Electrochemical reduction of irinotecan was investigated on a static mercury drop electrode using square‐wave voltammetry. The mechanism of irinotecan electroreduction is a complex, pH‐dependent, quasireversible process and includes the transfer of two electrons and two protons. In acidic medium, the first electron transfer reaction is followed by the chemical reaction, and the product of this chemical reaction undergoes further electrochemical reduction at more negative potentials. Both irinotecan and the product of its reduction adsorb on the mercury electrode surface. Based on the adsorptive character of irinotecan, a new adsorptive stripping square‐wave voltammetric method for its electroanalytical determination has been proposed. The voltammetric response could be used to determine irinotecan in the concentration range from 1×10−7 mol/L to 1.5×10−6 mol/L and from 5×10−9 mol/L to 1.2×10−7 mol/L, if the accumulation time is 20 s and 300 s, respectively. The calculated limit of detection for irinotecan was found to be 8.7×10−9 mol/L (if tacc=300 s).
Extended Investigation of Electrochemical CO2 Reduction in Ethanolamine Solutions by SECM
Authors: Filotás Daniel , Nagy Tibor , Nagy Livia , Mizsey Peter , Nagy Geza
Published: December 2017

The electrochemical reduction of carbon dioxide is very much in the focus of interest today. Intensive research is carried out in leading laboratories trying to work out methods for making useful materials from this unwanted greenhouse gas using solar or wind power generated excess electric energy. In this work, electrochemical reduction experiments are carried out in homemade cells supplied with different metal electrodes. Electrolytes containing carbon dioxide absorbing components like monoethanolamine (MEA) or KHCO3, KOH, and K2CO3 solutions are used. Metal‐containing species were noticed in the used electrolytes after being in contact with the metal working electrodes. Therefore parallel to the electrochemical measurements, the metal components in the electrolyte were checked with atomic absorption methods for getting better insight into the nature of the electrode passivation. This paper attempts to compare the behavior of different electrode materials (copper, nickel) in CO2 capturing media, and investigate of the products of the electrolysis using Scanning Electrochemical Microscopy (SECM), Atomic Absorption Spectroscopy (AAS) and gas chromatography.
Advance care planning (ACP) for specialists managing cirrhosis: A focus on patient‐centered care
Authors: Brisebois Amanda , Ismond Kathleen P. , Carbonneau Michelle , Kowalczewski Jan , Tandon Puneeta
Published: December 2017

Advance care planning (ACP) and goals of care designation (GCD) are being integrated into modern health care. In cirrhosis, uptake and adoption of these practices have been limited with physicians citing many perceived barriers and limitations. Recognizing the many tangible benefits of ACP and GCD processes in patients with life‐limiting chronic diseases, the onus is on health practitioners to initiate and direct these conversations with their patients and surrogates. Drawing upon the literature and our experiences in palliative care and cirrhosis, we provide an actionable framework that can be readily implemented into a busy clinical setting by a practitioner. Conversation starters, visual aids, educational resources (for patients and practitioners), and videos of mock physician‐patient scenarios are presented and discussed. Importantly, we have customized each of these tools to meet the unique health care needs of patients with cirrhosis. The inherent flexibility of our approach to ACP discussions and GCD can be further modified to accommodate practitioner preferences. Conclusion: In our clinics, this assemblage of “best practice tools” has been well received by patients and surrogates enabling us to increase the number of outpatients with cirrhosis who have actively contributed to their GCD before acute health events and are supported by well‐informed surrogates. (Hepatology 2018;67:2025‐2040).
Extracellular vesicles from mice with alcoholic liver disease carry a distinct protein cargo and induce macrophage activation through heat shock protein 90
Authors: Saha Banishree , Momen‐Heravi Fatemeh , Furi Istvan , Kodys Karen , Catalano Donna , Gangopadhyay Anwesha , Haraszti Reka , Satishchandran Abhishek , Iracheta‐Vellve Arvin , Adejumo Adeyinka , Shaffer Scott A. , Szabo Gyongyi
Published: December 2017

A salient feature of alcoholic liver disease (ALD) is Kupffer cell (KC) activation and recruitment of inflammatory monocytes and macrophages (MØs). These key cellular events of ALD pathogenesis may be mediated by extracellular vesicles (EVs). EVs transfer biomaterials, including proteins and microRNAs, and have recently emerged as important effectors of intercellular communication. We hypothesized that circulating EVs from mice with ALD have a protein cargo characteristic of the disease and mediate biological effects by activating immune cells. The total number of circulating EVs was increased in mice with ALD compared to pair‐fed controls. Mass spectrometric analysis of circulating EVs revealed a distinct signature for proteins involved in inflammatory responses, cellular development, and cellular movement between ALD EVs and control EVs. We also identified uniquely important proteins in ALD EVs that were not present in control EVs. When ALD EVs were injected intravenously into alcohol‐naive mice, we found evidence of uptake of ALD EVs in recipient livers in hepatocytes and MØs. Hepatocytes isolated from mice after transfer of ALD EVs, but not control EVs, showed increased monocyte chemoattractant protein 1 mRNA and protein expression, suggesting a biological effect of ALD EVs. Compared to control EV recipient mice, ALD EV recipient mice had increased numbers of F4/80hi cluster of differentiation 11b (CD11b)lo KCs and increased percentages of tumor necrosis factor alpha–positive/interleukin 12/23–positive (inflammatory/M1) KCs and infiltrating monocytes (F4/80intCD11bhi), while the percentage of CD206+CD163+ (anti‐inflammatory/M2) KCs was decreased. In vitro, ALD EVs increased tumor necrosis factor alpha and interleukin‐1β production in MØs and reduced CD163 and CD206 expression. We identified heat shock protein 90 in ALD EVs as the mediator of ALD‐EV‐induced MØ activation. Conclusion: Our study indicates a specific protein signature of ALD EVs and demonstrates a functional role of circulating EVs containing heat shock protein 90 in mediating KC/MØ activation in the liver. (Hepatology 2018;67:1986‐2000).
Impact of adolescent stress on the expression of stress‐related receptors in the hippocampus of animals exposed to alcohol prenatally
Authors: Raineki Charlis , Ellis Linda , Weinberg Joanne
Published: December 2017

Many functions of the hippocampus are affected by prenatal alcohol exposure (PAE). In particular, dysregulation of the stress response is especially important because individuals with PAE carry increased risks for exposure to stressful environments throughout life. Little is known, though, about how adolescent stress in the context of PAE‐related stress system dysregulation may further alter hippocampal development. Here, we investigate the short‐ and long‐term effects of adolescent chronic mild stress (CMS) on mRNA expression of stress‐related mineralocorticoid (MR), glucocorticoid (GR), and type 1 CRH (CRHR1) receptors in the dorsal and ventral hippocampal formation of PAE and control rats. Our results indicate that PAE affects the expression of stress‐related receptors in the hippocampus; however, PAE effects were more prominent during adolescence, as MR and CRHR1 mRNA expression were altered in both male and female PAE animals, with GR mRNA expression alterations observed only in PAE female. In adulthood, the effects of PAE were restricted to alterations in CRHR1 mRNA expression in females, while there were no effects in males. In contrast, the effects of adolescent CMS were more pronounced in adulthood, long after stress exposure termination. Importantly, PAE animals were less responsive to adolescent CMS, with effects only on CRHR1 in PAE animals compared to the altered MR, GR, and CRHR1 mRNA expression observed in controls. Together, our results show that PAE and adolescent CMS induce dynamic alterations in the expression of stress‐related receptors in the hippocampal formation that manifest differently depending on the age and sex of the animal.