bluuebunny/crossref_metadata_2025 huggingface dataset:
Does an aggressor's target choice matter? Assessing change in the social network prestige of aggressive youth
Authors: Andrews Naomi C. Z. , Hanish Laura D. , Santos Carlos E.
Published: January 2017

Based on a social dominance approach, aggression is conceptualized as a strategy used to gain position, power, and influence within the peer network. However, aggression may only be beneficial when targeted against particular peers; both victims’ social standing and the number of victims targeted may impact aggressors’ social standing. The current study examined associations between aggressors’ targeting tendencies (victims’ social standing and number of victims) and aggressors’ own social standing, both concurrently and over time. Analyses were conducted using three analytic samples of seventh and eighth grade aggressors (Ns ranged from 161 to 383, 49% girls; 50% Latina/o). Participants nominated their friends; nominations were used to calculate social network prestige. Peer nominations were used to identify aggressors and their victim(s). For each aggressor, number of victims and victims’ social network prestige were assessed. Aggressors with more victims and with highly prestigious victims had higher social network prestige themselves, and they increased more in prestige over time than aggressors with fewer victims and less prestigious victims (though there were some differences across analytic samples). Findings have implications for the need to extend the social dominance approach to better address the links between aggressors and victims. Aggr. Behav. 43:364–374, 2017. © 2017 Wiley Periodicals, Inc.
Novel synaptobrevin‐1 mutation causes fatal congenital myasthenic syndrome
Authors: Shen Xin‐Ming , Scola Rosana H. , Lorenzoni Paulo J. , Kay Cláudia S. K. , Werneck Lineu C. , Brengman Joan , Selcen Duygu , Engel Andrew G.
Published: January 2017

Objective

To identify the molecular basis and elucidate the pathogenesis of a fatal congenital myasthenic syndrome.

Methods

We performed clinical electrophysiology studies, exome and Sanger sequencing, and analyzed functional consequences of the identified mutation.

Results

Clinical electrophysiology studies of the patient revealed several‐fold potentiation of the evoked muscle action potential by high frequency nerve stimulation pointing to a presynaptic defect. Exome sequencing identified a homozygous c.340delA frameshift mutation in synaptobrevin 1 (SYB1), one of the three SNARE proteins essential for synaptic vesicle exocytosis. Analysis of both human spinal cord gray matter and normal human muscle revealed expression of the SYB1A and SYB1D isoforms, predicting expression of one or both isoforms in the motor nerve terminal. The identified mutation elongates the intravesicular C‐terminus of the A isoform from 5 to 71, and of the D isoform from 4 to 31 residues. Transfection of either mutant isoform into bovine chromaffin cells markedly reduces depolarization‐evoked exocytosis, and transfection of either mutant isoform into HEK cells significantly decreases expression of either mutant compared to wild type.

Interpretation

The mutation is pathogenic because elongation of the intravesicular C‐terminus of the A and D isoforms increases the energy required to move their C‐terminus into the synaptic vesicle membrane, a key step for fusion of the synaptic vesicle with the presynaptic membrane, and because it is predicted to reduce expression of either isoform in the nerve terminal.
Dielectric Properties of Sustainable Nanocomposites Based on Zein Protein and Lignin for Biodegradable Insulators
Authors: Oliviero Maria , Rizvi Reza , Verdolotti Letizia , Iannace Salvatore , Naguib Hani E. , Di Maio Ernesto , Neitzert Heinz C. , Landi Giovanni
Published: January 2017

Two types of lignin, alkali lignin and lignosulfonic acid sodium salt, are blended into thermoplastic zein through melt mixing in order to develop biodegradable insulator materials for multifunctional applications in electronics. The effects of lignin type and content on the dielectric properties of the resulting bio‐nanocomposites are investigated. The results indicate that, by modifying the structural arrangement of the zein with the use of lignin, it is possible to obtain bio‐nanocomposites characterized by tunable dielectric properties. The bio‐nanocomposites containing low amounts of lignin derivatives exhibit extensive protein structural changes together with a modification of the dielectric properties compared to the pristine thermoplastic zein. Changes in the dielectric properties of these systems are also observed to change over time, indicating a loss of plasticizer, as is evident by a decrease in the glass‐transition temperature. At high frequencies, the resulting values of the dielectric permittivity and of the loss tangent demonstrate that the bio‐nanocomposite can be used as biodegradable dielectric material for transient (temporary) electronics.
Gold Nanocomposite Bioink for Printing 3D Cardiac Constructs
Authors: Zhu Kai , Shin Su Ryon , van Kempen Tim , Li Yi‐Chen , Ponraj Vidhya , Nasajpour Amir , Mandla Serena , Hu Ning , Liu Xiao , Leijten Jeroen , Lin Yi‐Dong , Hussain Mohammad Asif , Zhang Yu Shrike , Tamayol Ali , Khademhosseini Ali
Published: January 2017

Bioprinting is the most convenient microfabrication method to create biomimetic three‐dimensional (3D) cardiac tissue constructs, that can be used to regenerate damaged tissue and provide platforms for drug screening. However, existing bioinks, which are usually composed of polymeric biomaterials, are poorly conductive and delay efficient electrical coupling between adjacent cardiac cells. To solve this problem, a gold nanorod (GNR)‐incorporated gelatin methacryloyl (GelMA)‐based bioink is developed for printing 3D functional cardiac tissue constructs. The GNR concentration is adjusted to create a proper microenvironment for the spreading and organization of cardiac cells. At optimized concentrations of GNR, the nanocomposite bioink has a low viscosity, similar to pristine inks, which allows for the easy integration of cells at high densities. As a result, rapid deposition of cell‐laden fibers at a high resolution is possible, while reducing shear stress on the encapsulated cells. In the printed GNR constructs, cardiac cells show improved cell adhesion and organization when compared to the constructs without GNRs. Furthermore, the incorporated GNRs bridge the electrically resistant pore walls of polymers, improve the cell‐to‐cell coupling, and promote synchronized contraction of the bioprinted constructs. Given its advantageous properties, this gold nanocomposite bioink may find wide application in cardiac tissue engineering.
Electric Field Tuning Molecular Packing and Electrical Properties of Solution‐Shearing Coated Organic Semiconducting Thin Films
Authors: Molina‐Lopez Francisco , Yan Hongping , Gu Xiaodan , Kim Yeongin , Toney Michael F. , Bao Zhenan
Published: January 2017

Recent improvements in solution‐coated organic semiconductors (OSCs) evidence their high potential for cost‐efficient organic electronics and sensors. Molecular packing structure determines the charge transport property of molecular solids. However, it remains challenging to control the molecular packing structure for a given OSC. Here, the application of alternating electric fields is reported to fine‐tune the crystal packing of OSC solution‐shearing coated at ambient conditions. First, a theoretical model based on dielectrophoresis is developed to guide the selection of the optimal conditions (frequency and amplitude) of the electric field applied through the solution‐shearing blade during coating of OSC thin films. Next, electric field‐induced polymorphism is demonstrated for OSCs with both herringbone and 2D brick‐wall packing motifs in 2,7‐dioctyl[1]benzothieno[3,2‐b][1]benzothiophene and 6,13‐bis(triisopropylsilylethynyl) pentacene, respectively. Favorable molecular packing can be accessible in some cases, resulting in higher charge carrier mobilities. This work provides a new approach to tune the properties of solution‐coated OSCs in functional devices for high‐performance printed electronics.
Novel Design Concepts of Efficient Mg‐Ion Electrolytes toward High‐Performance Magnesium–Selenium and Magnesium–Sulfur Batteries
Authors: Zhang Zhonghua , Cui Zili , Qiao Lixin , Guan Jing , Xu Huimin , Wang Xiaogang , Hu Pu , Du Huiping , Li Shizhen , Zhou Xinhong , Dong Shanmu , Liu Zhihong , Cui Guanglei , Chen Liquan
Published: January 2017

Developing high‐voltage Mg‐compatible electrolytes (>3.0 V vs Mg) still remains to be the biggest R&D challenge in the area of nonaqueous rechargeable Mg batteries. Here, the key design concepts toward exploring new boron‐based Mg salts in a specific way of highlighting the implications of anions are proposed for the first time. The well‐defined boron‐centered anion‐based magnesium electrolyte (BCM electrolyte) is successfully presented by facile one‐step mixing of tris(2H‐hexafluoroisopropyl) borate and MgF2 in 1,2‐dimethoxyethane, in which the structures of anions have been thoroughly investigated via mass spectrometry accompanied by NMR and Raman spectra. The first all‐round practical BCM electrolyte fulfills all requirements of easy synthesis, high ionic conductivity, wide potential window (3.5 V vs Mg), compatibility with electrophilic sulfur, and simultaneously noncorrosivity to coin cell assemblies. When utilizing the BCM electrolyte, the fast‐kinetics selenium/carbon (Se/C) cathode achieves the best rate capability and the sulfur/carbon (S/C) cathode exhibits an impressive prolonged cycle life than previously published reports. The BCM electrolyte offers the most promising avenue to eliminate the major roadblocks on the way to high‐voltage Mg batteries and the design concepts can shed light on future exploration directions toward high‐voltage Mg‐compatible electrolytes.
Tin(IV) Schiff base complexes derived from pyridoxal: Synthesis, spectroscopic properties and cytotoxicity
Authors: Galván‐Hidalgo José M. , Chans Guillermo M. , Ramírez‐Apan Teresa , Nieto‐Camacho Antonio , Hernández‐Ortega Simón , Gómez Elizabeth
Published: January 2017

The synthesis of monomeric pentacoordinated diorganotin(IV) complexes derived from pyridoxal hydrochloride and 4‐ or 5‐R‐substituted ortho‐aminophenols is described. The complexes were characterized using UV–visible, infrared, mass, 1H NMR, 13C NMR and 119Sn NMR spectral techniques. The molecular structure of three complexes was established using X‐ray diffraction: 3b and 3d show a distorted trigonal bipyramidal geometry, in which the basal plane is defined by the butyl groups and the iminic nitrogen atom, whereas the oxygen atoms from the aromatic ring occupy axial positions; in contrast, complex 3e exhibits a square pyramidal geometry. The cytotoxic activity of all complexes against human cell lines U‐251 (glioblastoma), K‐562 (chronic myelogenous leukemia), HCT‐15 (human colorectal cancer), MCF‐7 (human breast cancer) and SKLU‐1 (non‐small‐cell lung cancer) was evaluated, and the inhibitory percentage values indicated higher activity than the reference standard, cisplatin. Acute toxicity studies were performed in vivo for the prepared complexes to determine the lethal medium dose (LD50) after intraperitoneal administration to mice.
Oxidation of alkanes and secondary alcohols to ketones with tert‐butyl hydroperoxide catalyzed by a water‐soluble ruthenium complex under solvent‐free conditions
Authors: Zhang Yuecheng , Zhao Liyuan , Zhang Hongyu , Huang Rong , Zhao Jiquan
Published: January 2017

An easily synthesized water‐soluble ruthenium complex, [C6H5CH2N(CH3)2H]2[Ru(dipic)Cl3] (dipic =2,6‐pyridinedicarboxylate), as a catalyst showed high efficiency in the oxidation of alkanes and secondary alcohols to their corresponding ketones under solvent‐free and low‐catalyst‐loading conditions. This catalytic system could tolerate a variety of substrates and gave the corresponding ketones in good to excellent yields. The products were easily separated and purified due to the water solubility of the ruthenium complex.
Metabolic nodal response as a prognostic marker after neoadjuvant therapy for oesophageal cancer
Authors: Findlay J M , Bradley K M , Wang L M , Franklin J M , Teoh E J , Gleeson F V , Maynard N D , Gillies R S , Middleton M R
Published: January 2017

Background

The ability to predict recurrence and survival after neoadjuvant chemotherapy (NAC) and surgery for oesophageal cancer remains elusive. This study evaluated the role of [18F]fluorodeoxyglucose (FDG) PET–CT in assessing tumour and nodal response as a prognostic marker.

Methods

This was a single-centre UK cohort study. From 2006 to 2014, patients with oesophageal cancer staged with PET–CT before NAC, and restaged by CT or PET–CT before resection, were included. Pathological tumour response was evaluated using Mandard regression grades. Metabolic tumour and nodal responses (mTR and mNR respectively) were quantified using absolute and threshold reductions.

Results

Among 294 included patients, mTR and mNR independently predicted prognosis before surgery. After surgery, mNR (but not mTR), pathological tumour response, resection margin status and pathological node category predicted prognosis. Patients with FDG-avid nodal disease after NAC were at high risk of recurrence/death at 1 and 2 years (43 and 71 per cent respectively; P = 0·030 and P = 0·025 versus patients without avid nodes), and had a worse prognosis than patients with non-avid nodal metastases: hazard ratio 4·19 (95 per cent c.i. 1·87 to 9·40) and 2·11 (1·12 to 3·97) respectively versus patients without nodal metastases. Considering mTR and mNR response separately improved prognostication.

Conclusion

mNR is a novel prognostic factor, independent of conventional N status. Primary and nodal tumours may respond discordantly and patients with FDG-avid nodes after NAC have a poor prognosis.
Pentamethylcyclopentadienyl Titanium(IV) Amido Pyridylene Phenylene and Pentamethylcyclopentadienyl Titanacyclopropane Amido Complexes and their Behavior in the Polymerization of Ethylene and Cyclic Olefins
Authors: van der Ende Melita , Wang Dongren , Frey Wolfgang , Buchmeiser Michael R.
Published: January 2017

The reaction of pentamethylcyclopentadienyl titanium trichloride (Cp*TiCl3) with lithium N,N‐bis{6‐[2‐(diethylboryl)phenyl]pyridyl‐2‐yl}amide resulted in the formation of chlorido[η3‐N‐{6‐[2‐(diethylboryl)phenyl]pyridyl‐2‐yl}‐N‐(6‐C6H4)pyrid‐2‐yl)amido]pentamethylcyclopentadienyltitanium (Ti‐1). The structure of Ti‐1 was elucidated by using single‐crystal XRD. The same compound is formed upon the reaction of Cp*TiCl3 with lithium N‐{6‐[2‐(diethylboryl)phenyl]pyridyl‐2‐yl}‐N’‐[6‐(2‐bromophenyl)pyridyl‐2‐yl]amide. The reaction of N,N‐bis[6‐(2‐bromophen‐1‐yl)pyrid‐2‐yl]amine (4) with lithium hexamethyldisilazide followed by the addition of Cp*TiCl3 leads to the formation of [N,N‐bis{6‐(2‐bromophen‐1‐yl)pyrid‐2‐yl}amide]dichloridopentamethylcyclopentadienyltitanium (Ti‐2). The reaction of Ti‐1 with benzylmagnesium chloride yields the pentamethylcyclopentadienyl titanium vinyl complex pentamethylcyclopentadienyl{N‐(6‐phenylpyridyl‐2‐yl)‐N‐[6‐(2‐ethyl‐η2‐vinylboryl‐C6H4)pyrid‐2‐yl]amido}titanium (Ti‐3) by C−H activation; Ti‐3 is best described as a monosubstituted titanacyclopropane. Upon activation with methylaluminoxane (MAO), Ti‐1 produces linear, high‐density polyethylene with molecular weights >6×106 g mol−1, whereas Ti‐2 yielded ethyl‐branched polyethylene. Both Ti‐1 and Ti‐2 are able to copolymerize ethylene (E) with norborn‐2‐ene (NBE) and E with cyclopentene (CPE) and to terpolymerize E with NBE and CPE. Ti‐1 activated by MAO is also active in the ring‐opening metathesis polymerization of NBE to produce up to 97 % cis‐syndiotactic poly(NBE). The polymer structure of all resulting homo‐ and copolymers was elucidated by using 13C NMR spectroscopy.
Synthesis of [Bis(hexamethylene)cyclopentadienone]iron Tricarbonyl and its Application to the Catalytic Reduction of C=O Bonds
Authors: Vailati Facchini Sofia , Neudörfl Jörg‐Martin , Pignataro Luca , Cettolin Mattia , Gennari Cesare , Berkessel Albrecht , Piarulli Umberto
Published: January 2017

Herein, we report the synthesis of [bis(hexamethylene)cyclopentadienone]iron tricarbonyl (1 b) by the reaction of cyclooctyne with Fe(CO)5 and the investigation of its catalytic properties in C=O bond reduction. As a result of the peculiar reactivity of cyclooctyne, 1 b was formed in good yield (56 %) by intermolecular cyclative carbonylation/complexation with Fe(CO)5. Compound 1 b was characterized fully and its crystal structure was determined by using XRD. Catalytic tests revealed that, upon in situ activation with Me3NO, 1 b promotes the hydrogenation of ketones, aldehydes, and activated esters as well as the transfer hydrogenation of ketones and shows a higher activity than the classical “Knölker complex” (1 a). Studies on the hydrogenation kinetics in the presence of 1 a and 1 b (respectively) suggest that this difference in activity is probably caused by the better stability of the 1 b‐derived complex than that of the in situ generated Knölker–Casey catalyst.
Unexpected Electrochemical Transformation of Aminobenzene Sulfonic Acid Isomers to Respective Surface‐Confined‐Redox Active Quinones Bypassing Polyaniline on a MWCNT Surface
Authors: Mayuri Pinapeddavari , Kumar Annamalai Senthil
Published: January 2017

Electrochemical oxidation of aniline and its derivatives, such as aminobenzene sulfonic acid (SA), on solid electrodes [Pt, glassy carbon (GCE), indium tin oxide (ITO), and Au] leads to the formation of conducting polyaniline (PANI) and its derivatives as the only products in aqueous solution. We report here, for the first time, the unique and unexpected electrochemical transformation of ortho‐, meta‐ and para‐SA into highly redox‐active, adsorption‐controlled quinone isomers [catechol (CA), resorcinol (Re), hydroquinone (HQ)], without any PANI‐like product formation on a multiwalled carbon nanotube (MWCNT)‐modified GCE (GCE/MWCNT@Q, where Q=quinone) within a restricted potential cycling window (−0.4 to 0.4 V versus Ag/AgCl) in a neutral pH solution. It is proposed that upon the potential cycling of a 2.1 wt% iron‐impurity‐containing MWCNT‐modified GCE with a millimolar concentration of SA isomers, benzene (after deamination and desulfonation of SA) and hydrogen peroxide (from the oxygen reduction reaction at −0.4 V vs. Ag/AgCl) are formed as intermediate species, which are then converted to quinones and quinone‐like products through the electro‐Fenton reaction (utilizing the iron impurity and H2O2). One of the reaction intermediates, benzene, was identified (Mw=77.8±0.5 g mol−1) by using an in situ electrochemical quartz crystal microbalance coupled cyclic voltammetric technique. By using GCE/MWCNT@HQ as a model system, efficient electrocatalytic oxidation and sensing of the reduced form of nicotinamide adenine dinucleotide (NADH) was successfully demonstrated.
Experimental study of simultaneous removal of CO2 and SO2 in a spouted bed reactor
Authors: Fakhari Mohamad Ali , Rahimi Amir , Hatamipour Mohammad Sadegh , Fozooni Ali
Published: January 2017

This study experimentally investigated simultaneous absorption of CO2 and SO2 by NaOH solution in a powder particle spouted bed (PPSB) reactor. The Taguchi method was used for design of the experiments on the effect of the operating parameters of molar ratio of sorbent to CO2, inlet gas temperature and flow rate, and CO2 and SO2 concentrations in the gas stream on removal of CO2. In a PPSB reactor, when there is no SO2 to compete for absorption, the maximum removal efficiency of CO2 by NaOH solution was 56 %; in the presence of SO2, the average removal efficiency was less than 37 %. Although the CO2 and SO2 concentrations and inlet gas flow had significant effects on CO2 removal, inlet gas temperature and the molar ratio of sorbent to CO2 had little effect on removal efficiency.
Hypomethylating agents in combination with histone deacetylase inhibitors in higher risk myelodysplastic syndromes: Is there a light at the end of the tunnel?
Authors: Stahl Maximilian , Zeidan Amer M.
Published: January 2017

The combination of hypomethylating agents and histone deacetylase inhibitors demonstrates promising results in phase 1 trials but unfortunately disappointing results in all phase 2 trials to date.

See also pages 994‐1002.
Phase 2, randomized, double‐blind study of pracinostat in combination with azacitidine in patients with untreated, higher‐risk myelodysplastic syndromes
Authors: Garcia‐Manero Guillermo , Montalban‐Bravo Guillermo , Berdeja Jesus G. , Abaza Yasmin , Jabbour Elias , Essell James , Lyons Roger M. , Ravandi Farhad , Maris Michael , Heller Brian , DeZern Amy E. , Babu Sunil , Wright David , Anz Bertrand , Boccia Ralph , Komrokji Rami S. , Kuriakose Philip , Reeves James , Sekeres Mikkael A. , Kantarjian Hagop M. , Ghalie Richard , Roboz Gail J.
Published: January 2017

BACKGROUND

The prognosis of patients with higher‐risk myelodysplastic syndromes (MDS) remains poor despite available therapies. Histone deacetylase inhibitors have demonstrated activity in patients with MDS and in vitro synergy with azacitidine.

METHODS

A phase 2 randomized, placebo‐controlled clinical trial of azacitidine and pracinostat was conducted in patients who had International Prognostic Scoring System intermediate‐2–risk or high‐risk MDS. The primary endpoint was the complete response (CR) rate by cycle 6 of therapy.

RESULTS

Of 102 randomized patients, there were 51 in the pracinostat group and 51 in the placebo group. The median age was 69 years. The CR rate by cycle 6 of therapy was 18% and 33% (P = .07) in the pracinostat and placebo groups, respectively. No significant differences in overall survival (median, 16 vs 19 months, respectively; hazard ratio, 1.21; 95% confidence interval, 0.66‐2.23) or progression‐free survival (11 vs 9 months, respectively; hazard ratio, 0.82; 95% confidence interval, 0.546‐1.46) were observed between groups. Grade ≥3 adverse events occurred more frequently in the pracinostat group (98% vs 74%), leading to more treatment discontinuations (20% vs 10%).

CONCLUSIONS

The combination of azacitidine with pracinostat did not improve outcomes in patients with higher‐risk MDS. Higher rates of treatment discontinuation may partially explain these results, suggesting alternative dosing and schedules to improve tolerability may be required to determine the potential of the combination. Cancer 2017;123:994–1002. © 2016 American Cancer Society.
CSR Strategy in Technology Companies: Its Influence on Performance, Competitiveness and Sustainability
Authors: Bernal‐Conesa Juan Andres , de Nieves Nieto Carmen , Briones‐Peñalver Antonio Juan
Published: January 2017

In this paper, a structural equation model is presented to study the adoption of a strategy of Corporate Social Responsibility (CSR) within the Spanish technological industry sector, and how this strategy may influence its performance, competitiveness, and sustainability. For that reason, a survey was submitted to technology companies located in Spanish Science and Technology parks. The study shows that a CSR‐oriented strategy contributes significantly to the performance of the organisation. Moreover, CSR influences the competitiveness of technology companies, and particularly their sustainability. Copyright © 2017 John Wiley & Sons, Ltd and ERP Environment
Genome‐wide analysis of canonical Wnt target gene regulation in Xenopus tropicalis challenges β‐catenin paradigm
Authors: Nakamura Yukio , Hoppler Stefan
Published: January 2017

Wnt/β‐catenin signaling is an important cell‐to‐cell signaling mechanism that controls gene expression during embryonic development and is critically implicated in human diseases. Developmental, cellular, and transcriptional responses to Wnt signaling are remarkably context‐specific in different biological processes. While nuclear localization of β‐catenin is the key to activation of the Wnt/β‐catenin pathway and target gene expression, the molecular mechanisms of how the same Wnt/β‐catenin signaling pathway induces specific responses remain undetermined. Recent advances in high‐throughput sequencing technologies and the availability of genome information for Xenopus tropicalis have enabled us to uncover a genome‐wide view of Wnt/β‐catenin signaling in early vertebrate embryos, which challenges previous concepts about molecular mechanisms of Wnt target gene regulation. In this review, we summarize our experimental approaches, introduce the technologies we employed and focus on recent findings about Wnt target gene regulation from Xenopus research. We will also discuss potential functions of widespread β‐catenin binding in the genome that we discovered in this species.
Using Xenopus to understand human disease and developmental disorders
Authors: Sater Amy K. , Moody Sally A.
Published: January 2017

Model animals are crucial to biomedical research. Among the commonly used model animals, the amphibian, Xenopus, has had tremendous impact because of its unique experimental advantages, cost effectiveness, and close evolutionary relationship with mammals as a tetrapod. Over the past 50 years, the use of Xenopus has made possible many fundamental contributions to biomedicine, and it is a cornerstone of research in cell biology, developmental biology, evolutionary biology, immunology, molecular biology, neurobiology, and physiology. The prospects for Xenopus as an experimental system are excellent: Xenopus is uniquely well‐suited for many contemporary approaches used to study fundamental biological and disease mechanisms. Moreover, recent advances in high throughput DNA sequencing, genome editing, proteomics, and pharmacological screening are easily applicable in Xenopus, enabling rapid functional genomics and human disease modeling at a systems level.
Tools for live imaging of active Rho GTPases in Xenopus
Authors: Stephenson Rachel E. , Miller Ann L.
Published: January 2017

Rho family GTPases are signaling molecules that orchestrate cytoskeletal dynamics in a variety of cellular processes. Because they effect localized changes to the cytoskeleton only in their active (GTP‐bound) conformation, the ability to monitor the active state of Rho GTPases in space and time is critical for understanding their function. Here, we summarize popular tools used for live imaging of active Rho GTPases, outlining advantages and drawbacks of these approaches. Additionally, we highlight key features of the Xenopus laevis embryo that make it well‐suited for epithelial cell biology and discuss how application of Rho activity reporters in the Xenopus laevis embryo led to the discovery of a novel phenomenon, junctional Rho flares.
Probing forebrain to hindbrain circuit functions in Xenopus
Authors: Kelley Darcy B. , Elliott Taffeta M. , Evans Ben J. , Hall Ian C. , Leininger Elizabeth C. , Rhodes Heather J. , Yamaguchi Ayako , Zornik Erik
Published: January 2017

The vertebrate hindbrain includes neural circuits that govern essential functions including breathing, blood pressure and heart rate. Hindbrain circuits also participate in generating rhythmic motor patterns for vocalization. In most tetrapods, sound production is powered by expiration and the circuitry underlying vocalization and respiration must be linked. Perception and arousal are also linked; acoustic features of social communication sounds—for example, a baby's cry—can drive autonomic responses. The close links between autonomic functions that are essential for life and vocal expression have been a major in vivo experimental challenge. Xenopus provides an opportunity to address this challenge using an ex vivo preparation: an isolated brain that generates vocal and breathing patterns. The isolated brain allows identification and manipulation of hindbrain vocal circuits as well as their activation by forebrain circuits that receive sensory input, initiate motor patterns and control arousal. Advances in imaging technologies, coupled to the production of Xenopus lines expressing genetically encoded calcium sensors, provide powerful tools for imaging neuronal patterns in the entire fictively behaving brain, a goal of the BRAIN Initiative. Comparisons of neural circuit activity across species (comparative neuromics) with distinctive vocal patterns can identify conserved features, and thereby reveal essential functional components.
A frog's view of EphrinB signaling
Authors: Hwang Yoo‐Seok , Daar Ira O.
Published: January 2017

Cell–cell and cell–substrate adhesion are essential to the proper formation and maintenance of tissue patterns during development, and deregulation of these processes can lead to invasion and metastasis of cancer cells. Cell surface adhesion and signaling molecules are key players in both normal development and cancer progression. One set of cell surface proteins, the Eph receptor tyrosine kinases and their membrane‐bound ligands, ephrins, are significant regulators of these processes. During embryonic development, the Eph/ephrin signaling system is involved in cell–cell contact events that result in cell sorting and boundary formation between receptor and ligand bearing cells. When migrating cells that display the membrane bound ligands or receptors come in contact with cells bearing the cognate partner, the response may be adhesion or repulsion, ultimately leading to the proper positioning of these cells. During cancer progression, the signaling between these receptor/ligand pairs is often deregulated, leading to increased invasion and metastasis. To gain mechanistic insight into the pathways that mediate Eph receptor and ephrin signaling we have relied upon a very tractable system, the frog Xenopus. This model system has proven to be extremely versatile, and represents a relatively quick and manipulable system to explore signaling events and the in vivo processes affected by these signals.
Seeing the future: using Xenopus to understand eye regeneration
Authors: Tseng Ai‐Sun
Published: January 2017

Studies of Xenopus eye development have contributed considerably to the understanding of vertebrate neurogenesis, including eye field specification, cell fate determination and identification of genes critical for eye formation. This knowledge has served as a solid foundation for cellular and molecular examinations of the robust regenerative capacity of the Xenopus eye. The retina, lens, and the optic nerve are capable of regeneration after injury in both larval and adult stages. Here, we discuss the current models for studying eye regeneration in Xenopus and their potential applications for providing insights into human eye diseases. As Xenopus has many of the same tools that are available for other regeneration models, we thus highlight the distinct strengths and versatility of this organism that make it especially suited for extrapolating and testing strategies aimed at promoting regeneration and repair in eye tissues. Furthermore, we outline a promising future for the use of new techniques and approaches to address outstanding questions in understanding eye regeneration.
Effects of adding whole‐body vibration to routine day activity program on physical functioning in elderly with mild or moderate dementia: a randomized controlled trial
Authors: Lam Freddy M. H. , Liao L. R. , Kwok Timothy C. Y. , Pang Marco Y. C.
Published: January 2017

Objective

To evaluate the effects of whole‐body vibration (WBV) added to a routine activity program on lower limb strength, balance, and mobility among community‐dwelling individuals with mild or moderate dementia, compared with the routine program alone.

Methods

Fifty‐four older adults (40 women; mean (SD) age: 79.8 (6.1) years) with mild or moderate dementia were recruited from two daycare centers. The participants were randomly allocated to undergo a routine day activity program combined with WBV training (WBV at 30 Hz, 2‐mm peak‐to‐peak amplitude) or the routine program only without WBV for 9 weeks (18 sessions). The primary outcome was functional mobility, measured using the timed up‐and‐go test. The following secondary outcomes were evaluated: Berg Balance Scale, Tinetti balance assessment, time to complete 5 repetitions of sit‐to‐stand, Quality of Life in Alzheimer's disease questionnaire, and Activities‐specific Balance Confidence scale. The attendance rate and incidence of adverse events were also recorded.

Results

The attendance rate for the training was high (86.0%). The incidence of adverse events was low, with only two of the 27 participants in the WBV group reporting mild knee pain. While significant improvement in timed up‐and‐go, Berg Balance Scale, and Tinetti balance score was found in both groups, none of the outcomes demonstrated a significant group by time interaction.

Conclusions

WBV training is feasible and safe to use with people with mild or moderate dementia. However, it did not lead to further improvement in physical function and quality of life than the usual activity program provided at the daycare centers. Copyright © 2017 John Wiley & Sons, Ltd.
Test–retest reliability of functional connectivity networks during naturalistic fMRI paradigms
Authors: Wang Jiahui , Ren Yudan , Hu Xintao , Nguyen Vinh Thai , Guo Lei , Han Junwei , Guo Christine Cong
Published: January 2017

Functional connectivity analysis has become a powerful tool for probing the human brain function and its breakdown in neuropsychiatry disorders. So far, most studies adopted resting‐state paradigm to examine functional connectivity networks in the brain, thanks to its low demand and high tolerance that are essential for clinical studies. However, the test–retest reliability of resting‐state connectivity measures is moderate, potentially due to its low behavioral constraint. On the other hand, naturalistic neuroimaging paradigms, an emerging approach for cognitive neuroscience with high ecological validity, could potentially improve the reliability of functional connectivity measures. To test this hypothesis, we characterized the test–retest reliability of functional connectivity measures during a natural viewing condition, and benchmarked it against resting‐state connectivity measures acquired within the same functional magnetic resonance imaging (fMRI) session. We found that the reliability of connectivity and graph theoretical measures of brain networks is significantly improved during natural viewing conditions over resting‐state conditions, with an average increase of almost 50% across various connectivity measures. Not only sensory networks for audio–visual processing become more reliable, higher order brain networks, such as default mode and attention networks, but also appear to show higher reliability during natural viewing. Our results support the use of natural viewing paradigms in estimating functional connectivity of brain networks, and have important implications for clinical application of fMRI. Hum Brain Mapp 38:2226–2241, 2017. © 2017 Wiley Periodicals, Inc.
Network over‐connectivity differentiates autism spectrum disorder from other developmental disorders in toddlers: A diffusion MRI study
Authors: Conti E. , Mitra J. , Calderoni S. , Pannek K. , Shen K. K. , Pagnozzi A. , Rose S. , Mazzotti S. , Scelfo D. , Tosetti M. , Muratori F. , Cioni G. , Guzzetta A.
Published: January 2017

Advanced connectivity studies in toddlers with Autism Spectrum Disorder (ASD) are increasing and consistently reporting a disruption of brain connectivity. However, most of these studies compare ASD and typically developing subjects, thus providing little information on the specificity of the abnormalities detected in comparison with other developmental disorders (other‐DD). We recruited subjects aged below 36 months who received a clinical diagnosis of Neurodevelopmental Disorder (32 ASD and 16 other‐DD including intellectual disability and language disorder) according to DSM‐IV TR. Structural and diffusion MRI were acquired to perform whole brain probabilistic and anatomically constrained tractography. Network connectivity matrices were built encoding the number of streamlines (DNUM) and the tract‐averaged fractional anisotropy (DFA) values connecting each pair of cortical and subcortical regions. Network Based Statistics (NBS) was finally applied on the connectivity matrices to evaluate the network differences between the ASD and other‐DD groups. The network differences resulted in an over‐connectivity pattern (i.e., higher DNUM and DFA values) in the ASD group with a significance of P < 0.05. No contra‐comparison results were found. The over‐connectivity pattern in ASD occurred in networks primarily involving the fronto‐temporal nodes, known to be crucial for social‐skill development and basal ganglia, related to restricted and repetitive behaviours in ASD. To our knowledge, this is the first network‐based diffusion study comparing toddlers with ASD and those with other‐DD. Results indicate the detection of different connectivity patterns in ASD and other‐DD at an age when clinical differential diagnosis is often challenging. Hum Brain Mapp 38:2333–2344, 2017. © 2017 Wiley Periodicals, Inc.
Nanoscale physicochemical properties of chain‐ and step‐growth polymerized PEG hydrogels affect cell‐material interactions
Authors: Vats Kanika , Marsh Graham , Harding Kristen , Zampetakis Ioannis , Waugh Richard E. , Benoit Danielle S. W.
Published: January 2017

Poly(ethylene glycol) (PEG) hydrogels provide a versatile platform to develop cell instructive materials through incorporation of a variety of cell adhesive ligands and degradable chemistries. Synthesis of PEG gels can be accomplished via two mechanisms: chain and step growth polymerizations. The mechanism dramatically impacts hydrogel nanostructure, whereby chain polymerized hydrogels are highly heterogeneous and step growth networks exhibit more uniform structures. Underpinning these alterations in nanostructure of chain polymerized hydrogels are densely‐packed hydrophobic poly(methyl methacrylate) or poly(acrylate) kinetic chains between hydrophilic PEG crosslinkers. As cell‐material interactions, such as those mediated by integrins, occur at the nanoscale and affect cell behavior, it is important to understand how different modes of polymerization translate into nanoscale mechanical and hydrophobic heterogeneities of hydrogels. Therefore, chain‐ and step‐growth polymerized PEG hydrogels with macroscopically similar macromers and compliance (for example, methacrylate‐functionalized PEG (PEGDM), MW = 10 kDa and norbornene‐functionalized 4‐arm PEG (PEGnorb), MW = 10 kDa) were used to examine potential nanoscale differences in hydrogel mechanics and hydrophobicity using atomic force microscopy (AFM). It was found that chain‐growth polymerized network yielded greater heterogeneities in both stiffness and hydrophobicity as compared to step‐growth polymerized networks. These nanoscale heterogeneities impact cell‐material interactions, particularly human mesenchymal stem cell (hMSC) adhesion and spreading, which has implications in use of these hydrogels for tissue engineering applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1112–1122, 2017.
In situ data analytics and indexing of protein trajectories
Authors: Johnston Travis , Zhang Boyu , Liwo Adam , Crivelli Silvia , Taufer Michela
Published: January 2017

The transition toward exascale computing will be accompanied by a performance dichotomy. Computational peak performance will rapidly increase; I/O performance will either grow slowly or be completely stagnant. Essentially, the rate at which data are generated will grow much faster than the rate at which data can be read from and written to the disk. MD simulations will soon face the I/O problem of efficiently writing to and reading from disk on the next generation of supercomputers. This article targets MD simulations at the exascale and proposes a novel technique for in situ data analysis and indexing of MD trajectories. Our technique maps individual trajectories' substructures (i.e., α‐helices, β‐strands) to metadata frame by frame. The metadata captures the conformational properties of the substructures. The ensemble of metadata can be used for automatic, strategic analysis within a trajectory or across trajectories, without manually identify those portions of trajectories in which critical changes take place. We demonstrate our technique's effectiveness by applying it to 26.3k helices and 31.2k strands from 9917 PDB proteins and by providing three empirical case studies. © 2017 Wiley Periodicals, Inc.
A simple 2D composite image analysis technique for the crystal growth study of L‐ascorbic acid
Authors: Kumar Krishan , Kumar Virender , Lal Jatin , Kaur Harmeet , Singh Jasbir
Published: January 2017

This work was destined for 2D crystal growth studies of L‐ascorbic acid using the composite image analysis technique. Growth experiments on the L‐ascorbic acid crystals were carried out by standard (optical) microscopy, laser diffraction analysis, and composite image analysis. For image analysis, the growth of L‐ascorbic acid crystals was captured as digital 2D RGB images, which were then processed to composite images. After processing, the crystal boundaries emerged as white lines against the black (cancelled) background. The crystal boundaries were well differentiated by peaks in the intensity graphs generated for the composite images. The lengths of crystal boundaries measured from the intensity graphs of composite images were in good agreement (correlation coefficient “r” = 0.99) with the lengths measured by standard microscopy. On the contrary, the lengths measured by laser diffraction were poorly correlated with both techniques. Therefore, the composite image analysis can replace the standard microscopy technique for the crystal growth studies of L‐ascorbic acid.
Histological features of the vomeronasal organ in the giraffe, Giraffa camelopardalis
Authors: Kondoh Daisuke , Nakamura Kentaro G. , Ono Yurie S. , Yuhara Kazutoshi , Bando Gen , Watanabe Kenichi , Horiuchi Noriyuki , Kobayashi Yoshiyasu , Sasaki Motoki , Kitamura Nobuo
Published: January 2017

The vomeronasal organ (VNO) that preferentially detects species‐specific substances is diverse among animal species, and its morphological properties seem to reflect the ecological features of animals. This histological study of two female reticulated giraffes (Giraffa camelopardalis reticulata) found that the VNO is developed in giraffes. The lateral and medial regions of the vomeronasal lumen were covered with sensory and nonsensory epithelia, respectively. The vomeronasal glands were positive for periodic acid‐Schiff and alcian blue (pH 2.5) stains. The VNO comprises several large veins like others in the order Cetartiodactyla, suggesting that these veins function in a pumping mechanism in this order. In addition, numerous thin‐walled vessels located immediately beneath the epithelia covering the lumen entirely surrounded the vomeronasal lumen. This sponge‐like structure might function as a specific secondary pump in giraffes.
Gene therapy for achromatopsia
Authors: Michalakis Stylianos , Schön Christian , Becirovic Elvir , Biel Martin
Published: January 2017

The present review summarizes the current status of achromatopsia (ACHM) gene therapy‐related research activities and provides an outlook for their clinical application. ACHM is an inherited eye disease characterized by a congenital absence of cone photoreceptor function. As a consequence, ACHM is associated with strongly impaired daylight vision, photophobia, nystagmus and a lack of color discrimination. Currently, six genes have been linked to ACHM. Up to 80% of the patients carry mutations in the genes CNGA3 and CNGB3 encoding the two subunits of the cone cyclic nucleotide‐gated channel. Various animal models of the disease have been established and their characterization has helped to increase our understanding of the pathophysiology associated with ACHM. With the advent of adeno‐associated virus vectors as valuable gene delivery tools for retinal photoreceptors, a number of promising gene supplementation therapy programs have been initiated. In recent years, huge progress has been made towards bringing a curative treatment for ACHM into clinics. The first clinical trials are ongoing or will be launched soon and are expected to contribute important data on the safety and efficacy of ACHM gene supplementation therapy.
On the Size‐Ramsey Number of Hypergraphs
Authors: Dudek Andrzej , Fleur Steven La , Mubayi Dhruv , Rödl Vojtech
Published: January 2017

The size‐Ramsey number of a graph G is the minimum number of edges in a graph H such that every 2‐edge‐coloring of H yields a monochromatic copy of G. Size‐Ramsey numbers of graphs have been studied for almost 40 years with particular focus on the case of trees and bounded degree graphs.

We initiate the study of size‐Ramsey numbers for k‐uniform hypergraphs. Analogous to the graph case, we consider the size‐Ramsey number of cliques, paths, trees, and bounded degree hypergraphs. Our results suggest that size‐Ramsey numbers for hypergraphs are extremely difficult to determine, and many open problems remain.
Progress in modification of sunflower oil to expand its industrial value
Authors: Rauf Saeed , Jamil Nazia , Tariq Sultan Ali , Khan Maria , Kausar Maria , Kaya Yalcin
Published: January 2017

Increasing the sunflower seed oil content as well as improving its quality makes it compatible for industrial demands. This is an important breeding objective of sunflower which increases its market value and ensures high returns for the producers. The present review focuses on determining the progress of improving sunflower seed oil content and modifying its quality by empirical and advanced molecular breeding methods. It is known that the sunflower oil content and quality have been altered through empirical selection methods and mutation breeding programmes in various parts of the world. Further improvement in seed oil content and its components (such as phytosterols, tocopherols and modified fatty acid profile) has been slowed down due to low genetic variation in elite germplasm and complex of hereditary traits. Introgression from wild species can be carried out to modify the fatty acids profile and tocopherol contents with linkage drags. Different transgenes introduced through biotechnological methods may produce novel long‐chain fatty acids within sunflower oil. Bio‐engineering of sunflower oil could allow it to be used in diverse industrial products such as bio‐diesel or bio‐plastics. These results showed that past and current trends of modifying sunflower oil quality are essential for its further expansion as an oilseed crop. © 2017 Society of Chemical Industry
Short‐term and long‐term follow‐up of pulmonary function in patients with COPD after total laryngectomy: A prospective study
Authors: Schönwald Charlotte , Körber Maria Isabel , Beutner Dirk , Pfister Roman , Frank Konrad , Guntinas‐Lichius Orlando , Michels Guido
Published: January 2017

Objective

There exists no standardized method for examining lung function in laryngectomized patients.

Study Design and Methods

We established a base plate adapter (BPA) system for patients after laryngectomy. In 10 patients with chronic obstructive pulmonary disease (COPD), we evaluated pulmonary function before laryngectomy, as well as 2 weeks and 3 months after laryngectomy.

Results

The BPA system was well tolerated and delivered reliable results comparable to measurements with a mouthpiece. The parameters forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and mean forced expiratory flow between 25% and 75% of forced vital capacity (MFEF25–75) changed in the early postoperative examinations (2 weeks postoperative), whereas MFEF25–75, FEF75, peak expiratory flow (PEF), and peak inspiratory flow (PIF)) showed differences from baseline in long‐term follow‐up (3 months postoperative).

Conclusion

We provide a practicable method of lung function testing in laryngectomized patients with COPD that is essential to tailor inhalation therapy despite tracheotomy. Lung function measurements of laryngectomized patients with COPD should be performed under stable clinical conditions a few weeks after surgery. Guidelines of COPD might be complemented considering the subgroup of laryngectomized patients.

Level of Evidence

4. Laryngoscope, 127:2045–2049, 2017