bluuebunny/crossref_metadata_2025 huggingface dataset:
Giant Up-Conversion Efficiency of InGaAs Quantum Dots in a Planar Microcavity
Authors: Xu Qinfeng , Piermarocchi Carlo , Pershin Yuriy V. , Salamo G. J. , Xiao Min , Wang Xiaoyong , Shih Chih-Kang
Published: February 2014

Self-assembled InGaAs quantum dots (QDs) were fabricated inside a planar microcavity with two vertical cavity modes. This allowed us to excite the QDs coupled to one of the vertical cavity modes through two propagating cavity modes to study their down- and up-converted photoluminescence (PL). The up-converted PL increased continuously with the increasing temperature, reaching an intensity level comparable to that of the down-converted PL at ~120 K. This giant efficiency in the up-converted PL of InGaAs QDs was enhanced by about 2 orders of magnitude with respect to a similar structure without cavity. We tentatively explain the enhanced up-converted signal as a direct consequence of the modified spontaneous emission properties of the QDs in the microcavity, combined with the phonon absorption and emission effects.
Direct detection of circulating microRNAs in serum of cancer patients by coupling protein-facilitated specific enrichment and rolling circle amplification
Authors: Hong Cheng-Yi , Chen Xian , Li Juan , Chen Jing-Hua , Chen Guonan , Yang Huang-Hao
Published: February 2014

A simple method for direct detection of circulating miRNAs in serum by coupling p19 protein-facilitated specific enrichment and RCA.
A p-type Ti(iv)-based metal–organic framework with visible-light photo-response
Authors: Gao Junkuo , Miao Jianwei , Li Pei-Zhou , Teng Wen Yuan , Yang Ling , Zhao Yanli , Liu Bin , Zhang Qichun
Published: February 2014

Photoelectrochemical studies on a new Ti(iv)-based porous metal–organic framework (NTU-9, bandgap 1.72 eV) indicated that NTU-9 is a p-type semiconductor with visible-light-driven photoactivity.
Rapid, high yield, directed addition of quantum dots onto surface bound linear DNA origami arrays
Authors: Rahman Masudur , Neff David , Norton Michael L.
Published: February 2014

High yield biomolecule or conjugate assembly onto 1D DNA origami arrays and macroscopic alignment of the arrays via combing are demonstrated.
Use of the oxime–oximato binding mode to stabilise mixed valence copper iodide polymer networks using dipyridyl ketone oxime ligands
Authors: Argyle Victoria J. , Roxburgh Marina , Hanton Lyall R.
Published: February 2014

Coordination polymers formed from copper iodide and four isomeric dipyridyl ketone oxime ligands showed the importance the oxime–oximato bridge on the formation of mixed valence Cu(i)/Cu(ii) polymers.
Selectivity in the catalytic hydrogenation of cinnamaldehyde promoted by Pt/SiO2 as a function of metal nanoparticle size
Authors: Zhu Yujun , Zaera Francisco
Published: February 2014

In the catalytic hydrogenation of cinnamaldehyde by platinum, selectivity is structure insensitive but total activity is associated with flat terraces.
Nickel-catalyzed oxidative coupling of alkynes and arylboronic acids using the metal–organic framework Ni2(BDC)2(DABCO) as an efficient heterogeneous catalyst
Authors: Truong Thanh , Nguyen Chung K. , Tran Thi V. , Nguyen Tung T. , Phan Nam T. S.
Published: February 2014

The first Ni-catalyzed oxidative coupling of alkynes and arylboronic acids.
A magnetic and conductive study on a stable defective extended cobalt atom chain
Authors: Wang Wen-Zhen , Wu Yang , Ismayilov Rayyat H. , Kuo Juao-Hui , Yeh Chen-Yu , Lee Hsuan-Wei , Fu Ming-Dung , Chen Chun-hsien , Lee Gene-Hsiang , Peng Shie-Ming
Published: February 2014

A defective extended cobalt atom chain complex has been synthesized and the magnetism and conductance are studied. The formation and the electron transporting pathway of EMACs are investigated.
Basicities and transesterification activities of Zn–Al hydrotalcites-derived solid bases
Authors: Liu Qianhe , Wang Bingchun , Wang Congxin , Tian Zhijian , Qu Wei , Ma Huaijun , Xu Renshun
Published: February 2014

Upon calcination, as-prepared Zn–Al hydrotalcites are converted into dehydrated Zn–Al hydrotalcites and oxides, which show catalytic activities in the transesterification.
Dependence of coupling of quasi 2-D MoS2 with substrates on substrate types, probed by temperature dependent Raman scattering
Authors: Su Liqin , Zhang Yong , Yu Yifei , Cao Linyou
Published: February 2014

The coupling of quasi 2-D MoS2 with substrates on different substrate types has been studied and probed by temperature dependent Raman scattering.
Room-temperature self-powered ethanol sensing of a Pd/ZnO nanoarray nanogenerator driven by human finger movement
Authors: Lin Yujie , Deng Ping , Nie Yuxin , Hu Yuefeng , Xing Lili , Zhang Yan , Xue Xinyu
Published: February 2014

Room-temperature self-powered ethanol sensing has been realized from a Pd/ZnO nanoarray nanogenerator under the driving of human finger movement.
Topological behavior mimicking ethylene–hexene copolymers using branched lactones and macrolactones
Authors: Jasinska-Walc Lidia , Hansen Michael Ryan , Dudenko Dmytro , Rozanski Artur , Bouyahyi Miloud , Wagner Manfred , Graf Robert , Duchateau Robbert
Published: February 2014

A highly effective and facile technique for ring-opening copolymerization of lactones with macrolactone towards polyolefin-like materials is presented.
Tuning the magnetic behaviors in [FeIII12LnIII4] clusters with aromatic carboxylate ligands
Authors: Liu Sui-Jun , Zeng Yong-Fei , Xue Li , Han Song-De , Jia Ji-Min , Hu Tong-Liang , Bu Xian-He
Published: February 2014

Six new Fe–Ln clusters composed of a Fe12Ln4 core derived from two monocarboxylate ligands have been successfully obtained with a step-by-step strategy. Magnetic analyses suggest that 1–6 show different magnetic properties, and 2 and 6 display SMM-like behaviors.
Branching and size of CTAB-coated gold nanostars control the colorimetric detection of bacteria
Authors: Verma Mohit S. , Chen Paul Z. , Jones Lyndon , Gu Frank X.
Published: February 2014

The size and degree of branching of gold nanostars control the colorimetric response when detecting Staphylococcus aureus.
Preparation of porous (Ni,Co)3(BO3)2/Ni(OH)2nanosheet networks as pseudocapacitor materials with superior performance
Authors: Chen Yuanzhen , Liu Yongning , Yan Wei
Published: February 2014

Hydrogen expanded (Ni,Co)3(BO3)2/Ni(OH)2nanoflakes into a porous structure and thereby made it obtain a big SSA and superior pseudocapacitor performance.
Prolonging the lifetime of excited electrons of QDs by capping them with π-conjugated thiol ligands
Authors: Chang Jie , Xia Hongbo , Wu Suli , Zhang Shufen
Published: February 2014

A new strategy is reported here to stabilize the excited electrons within QDs using-conjugated ligand. An electron delocalized field is formed by mixing the LUMO energy levels of π-conjugated ligand with conductive band-edge energy (Ecb) of CdTe QDs, which will supply the excited electron with a more stable environment.
A photofuel cell comprising titanium oxide and silver(i/0) photocatalysts for use of acidic water as a fuel
Authors: Ogura Yuta , Okamoto Seiji , Itoi Takaomi , Fujishima Yukiko , Yoshida Yusuke , Izumi Yasuo
Published: February 2014

A photofuel cell comprising two photocatalysts TiO2and Ag–TiO2is demonstrated to rectify the electron flow due to the Schottky barrier.
Highly durable fuel cell electrodes based on ionomers dispersed in glycerol
Authors: Kim Y. S. , Welch C. F. , Mack N. H. , Hjelm R. P. , Orler E. B. , Hawley M. E. , Lee K. S. , Yim S.-D. , Johnston C. M.
Published: February 2014

A major, unprecedented improvement in the durability of polymer electrolyte membrane fuel cells is obtained by tuning the properties of the interface between the catalyst and the ionomer by choosing the appropriate dispersing medium.
Catalytic hydrogenation of nitrophenols and nitrotoluenes over a palladium/graphene nanocomposite
Authors: Sun Jingwen , Fu Yongsheng , He Guangyu , Sun Xiaoqiang , Wang Xin
Published: February 2014

A plausible mechanism for the reduction of p-nitrophenol catalyzed by a Pd/G catalyst in the presence of sodium borohydride.
Gold complexes as antimicrobial agents: an overview of different biological activities in relation to the oxidation state of the gold ion and the ligand structure
Authors: Glišić Biljana Đ. , Djuran Miloš I.
Published: February 2014

A survey of the results achieved in the field of gold(i) and gold(iii) complexes as potential antimicrobial agents.
Synthesis of 3-acyltetramates by side chain manipulation and their antibacterial activity
Authors: Tan Song Wei Benjamin , Chai Christina L. L. , Moloney Mark G.
Published: February 2014

An efficient approach for the introduction of 3-acyl side chain groups onto a core tetramate system, which are suitable for further manipulation by nucleophilic displacement or Horner–Wadsworth–Emmons coupling, provides access to a diverse library of substituted tetramates related to two distinct classes of natural products, equisetin and pramanicin.
Rhodium(0) nanoparticles supported on nanotitania as highly active catalyst in hydrogen generation from the hydrolysis of ammonia borane
Authors: Akbayrak Serdar , Gençtürk Serap , Morkan İzzet , Özkar Saim
Published: February 2014

Rhodium(0) nanoparticles supported on nanotitania as a highly active catalyst in hydrogen generation from the hydrolysis of ammonia borane.
An Evaluation of Reading Comprehension of Expository Text in Adults With Traumatic Brain Injury
Authors: Sohlberg McKay Moore , Griffiths Gina G. , Fickas Stephen
Published: February 2014

Purpose

This project was conducted to obtain information about reading problems of adults with traumatic brain injury (TBI) with mild-to-moderate cognitive impairments and to investigate how these readers respond to reading comprehension strategy prompts integrated into digital versions of text.

Method

Participants from 2 groups, adults with TBI (
n
= 15) and matched controls (
n
= 15), read 4 different 500-word expository science passages linked to either a strategy prompt condition or a no-strategy prompt condition. The participants' reading comprehension was evaluated using sentence verification and free recall tasks.

Results

The TBI and control groups exhibited significant differences on 2 of the 5 reading comprehension measures: paraphrase statements on a sentence verification task and communication units on a free recall task. Unexpected group differences were noted on the participants' prerequisite reading skills. For the within-group comparison, participants showed significantly higher reading comprehension scores on 2 free recall measures: words per communication unit and type–token ratio. There were no significant interactions.

Conclusion

The results help to elucidate the nature of reading comprehension in adults with TBI with mild-to-moderate cognitive impairments and endorse further evaluation of reading comprehension strategies as a potential intervention option for these individuals. Future research is needed to better understand how individual differences influence a person's reading and response to intervention.
Role of Maternal Gesture Use in Speech Use by Children With Fragile X Syndrome
Authors: Hahn Laura J. , Zimmer B. Jean , Brady Nancy C. , Swinburne Romine Rebecca E. , Fleming Kandace K.
Published: February 2014

Purpose

The purpose of this study was to investigate how maternal gesture relates to speech production by children with fragile X syndrome (FXS).

Method

Participants were 27 young children with FXS (23 boys, 4 girls) and their mothers. Videotaped home observations were conducted between the ages of 25 and 37 months (toddler period) and again between the ages of 60 and 71 months (child period). The videos were later coded for types of maternal utterances and maternal gestures that preceded child speech productions. Children were also assessed with the Mullen Scales of Early Learning at both ages.

Results

Maternal gesture use in the toddler period was positively related to expressive language scores at both age periods and was related to receptive language scores in the child period. Maternal proximal pointing, in comparison to other gestures, evoked more speech responses from children during the mother–child interactions, particularly when combined with
wh
-questions.

Conclusion

This study adds to the growing body of research on the importance of contextual variables, such as maternal gestures, in child language development. Parental gesture use may be an easily added ingredient to parent-focused early language intervention programs.
Link decision algorithm in underlay cognitive radio networks over a Rayleigh fading channel
Authors: Tan Xiaobo , Zhang Hang , Hu Jian
Published: February 2014

A link decision algorithm is proposed for underlay cognitive radio network over a Rayleigh fading channel. The authors assume that a diversity combining technique is available at the secondary receiver. Under the constraints on average interference power (AIC) at the primary receiver (PR) and peak transmit power at the secondary transmitter (ST), for a given bit error ratio (BER) target, the link decision problem is formulated as an optimisation problem. Then, Lagrange dual decomposition is applied to derive the optimal transmit power and the modulation level of the ST to obtain its achievable transmission rate. Based on the optimal transmit power and the modulation level, a practical link decision algorithm which requires integral modulation levels is also proposed. Achievable transmission rates and outage probabilities of the proposed algorithms for various power constraints, BER requirements and different number of diversity branches are analysed. Finally, the influence of the primary user's transmission activities (including transmit power and non‐active probability) on the transmission performance of the secondary link is also discussed. They compare all the aforementioned results with the case when peak interference power constraint (PIC) at the PR is employed instead of the AIC. Simulations reveal that the AIC is indeed superior over the PIC. All these numerical results validate the proposed algorithms and the analysis.
Design of a chaos synchronisation‐based maximum power tracking controller for a wind‐energy‐conversion system
Authors: Zhan Tung‐Sheng , Chen Jian Liung , Chen Shi‐Jaw , Huang Cong‐Hui , Lin Chia‐Hung
Published: February 2014

This study proposes a maximum power tracking (MPT) controller based on chaos synchronisation (CS) for a wind‐energy‐conversion system. The output power conversion of a wind generator depends on the wind speed, and therefore the optimal conversion of wind energy can be obtained by a variable‐speed variable‐frequency model. Based on a sensorless controller, CS can express dynamic behaviours by using an incremental conductance to adjust the terminal voltage to the maximum power point. A voltage detector based on the Sprott system is used to track the desired voltage and to control the duty cycle of a boost converter. For a permanent‐magnet synchronous generator, the simulation results demonstrate the effectiveness of the proposed MPT controller.
Validation of Hemostasis and Coagulation Assays: Recommendations and Guidelines
Authors: Marlar Richard , Gausman Jana , Engel James
Published: February 2014

The clinical hemostasis laboratory is a complex testing arena which employs numerous coagulation assays and spans several different test methodologies. Adding further complexity, these test results are expressed in a wide variety of unique units (concentration, activity, time, percentage, and ratio). Unfortunately, many of these reference values are derived from a local plasma pool or manufacturer's standards, as there are few established international standards. These three main issues complicate the validation and performance of the coagulation testing. Before an assay can be introduced into clinical use, both analytical and clinical performance parameters must be validated or verified using the standard validation procedures of the laboratory. This article summarizes the initial evaluation and validation processes of the coagulation laboratory, which sometimes can be difficult concepts to implement. A standardized validation protocol is described in this article and, if used, will help to objectively evaluate the assay performance and determine if it meets acceptable laboratory criteria.
The Influence of Diet and Nutrients on Platelet Function
Authors: McEwen Bradley
Published: February 2014

Cardiovascular disease (CVD) is the leading cause of death worldwide. Platelet activation and aggregation play an integral role in hemostasis and thrombosis. Diets and nutrients play a potential role in modifying CVD progression, particularly in platelet function, and have the potential of altering platelet function tests. Diets such as Mediterranean diet, high in omega-3 polyunsaturated fatty acids (PUFA), and vegetarian diets have inverse relationships with CVD. Dark chocolate, foods with low glycemic index, garlic, ginger, omega-3 PUFA, onion, purple grape juice, tomato, and wine all reduce platelet aggregation. Dark chocolate and omega-3 PUFA also reduce P-selectin expression. In addition, dark chocolate reduces PAC-1 binding and platelet microparticle formation. Berries inhibit platelet function (PFA-100). Energy drinks have been shown to increase platelet aggregation and caffeine increases platelet microparticle formation. Therefore, repeat testing of platelet function may be required, not only after exclusion of known antiplatelet medications but also potentially after exclusion of dietary substances/nutrients that could have plausibly affected initial test data.
Proficiency Testing Results for Heparin-Induced Thrombocytopenia in North America
Authors: Smock Kristi , Ledford-Kraemer Marlies , Meijer Piet , Hsu Peihong , Van Cott Elizabeth
Published: February 2014

Between 2010 and 2012, North American Specialized Coagulation Laboratory Association (NASCOLA) distributed five proficiency testing challenges to evaluate laboratory testing for heparin-induced thrombocytopenia (HIT). Results (n = 355) were submitted from 43 unique laboratories for 10 samples (3 positive, 2 weak positive, and 5 negative). The vast majority of results were from commercial enzyme-linked immunosorbent assay (ELISA) methods, predominantly polyvalent assays. Laboratories performed well in the classification of clear negative and positive samples. All results (100%) submitted for the five negative samples (n = 173) and 97% of immunological results submitted for the three positive samples (n = 105) were correctly classified (the incorrect responses were two borderline classifications and, from a gel-agglutination method, one negative classification). There was more difficulty in the classification of the two weak positive samples (n = 70). In one survey, 61% of results from the weak positive sample were classified as positive, while 21% were called negative, 16% were called borderline, and 2% were called inconclusive. In a second survey, 16% of results from the weak positive sample were called positive, while 56% were called negative, and 28% were called borderline. Significant interlaboratory variation was observed for ELISA results, with coefficients of variation of about 20 to 30%. We conclude that there is variability in HIT laboratory testing and that identification of weak positive samples can be challenging.
The UK National External Quality Assessment Scheme for Heritable Bleeding Disorders
Authors: Perry David , Cumming Tony , Goodeve Anne , Hill Marian , Jennings Ian , Kitchen Steven , Walker Isobel
Published: February 2014

Molecular genetic analysis of families with hemophilia and other heritable bleeding disorders is a frequently requested laboratory investigation. In the United Kingdom, laboratories undertaking genetic testing must participate in a recognized external quality assessment scheme for formal accreditation. The UK National External Quality Assessment Scheme (UK NEQAS) for heritable bleeding disorders was established in its current format in 2003, and currently has 27 registered participants in the United Kingdom, the European Union (EU), and the non-EU countries. Two exercises per annum are circulated to participants comprising either whole blood or DNA isolated from cell lines, and laboratories are allowed 6 weeks to analyze the samples and generate a report. Reports are assessed by a panel comprising clinicians and scientists with expertise in this area. Samples to date have involved analysis of the F8 gene (10 exercises), the F9 gene (4 exercises), and the VWF gene (3 exercises) and have comprised a wide spectrum of mutations representing the routine workload encountered in the molecular genetics laboratory. The majority of laboratories in each exercise passed, but a small number did not and reasons for failing included clerical errors, genotyping inaccuracies, and a failure to correctly interpret data. Overall we have seen an improvement in quality of reports submitted for assessment, with a more concise format that will be of value to referring clinicians and counsellors. Informal feedback from participants has been very positive.
Potentially preventable hospitalisations: are they a useful marker of access to and experience of care in general practice among people with type 2 diabetes?
Authors: Manski-Nankervis Jo-Anne , Furler John , Audehm Ralph , Blackberry Irene , Young Doris
Published: February 2014

The aim of the present study was to explore access to and experience of care in general practice among patients admitted to hospital with a type 2 diabetes mellitus-related potentially preventable hospitalisation (PPH). Forty-eight patients admitted to two public hospitals in the north and west of Melbourne completed a survey and 13 patients were interviewed. Patients generally had long-standing diabetes with multimorbidity and were relatively socioeconomically disadvantaged. Nearly two-thirds reported more than one hospital admission in the prior 12 months, and 74% of respondents were able to access their preferred general practitioner (GP) on either the same or next day. Emotional support, time and continuity of care with their GP were important to patients, but they recognised many patient barriers to optimal care, including self-management and social and economic factors. Patients that accessed specialist care perceived that GPs had limited role in their disease management. Although the patients in this study experienced good access to care, they also identified several factors that were arguably outside the scope of general practice management, indicating that their admissions to hospital may not have been avoidable.
Impact of climate change on global malaria distribution
Authors: Caminade Cyril , Kovats Sari , Rocklov Joacim , Tompkins Adrian M. , Morse Andrew P. , Colón-González Felipe J. , Stenlund Hans , Martens Pim , Lloyd Simon J.
Published: February 2014

Significance

This study is the first multimalaria model intercomparison exercise. This is carried out to estimate the impact of future climate change and population scenarios on malaria transmission at global scale and to provide recommendations for the future. Our results indicate that future climate might become more suitable for malaria transmission in the tropical highland regions. However, other important socioeconomic factors such as land use change, population growth and urbanization, migration changes, and economic development will have to be accounted for in further details for future risk assessments.
Suppression of Mediator is regulated by Cdk8-dependent Grr1 turnover of the Med3 coactivator
Authors: Gonzalez Deyarina , Hamidi Nurul , Del Sol Ricardo , Benschop Joris J. , Nancy Thomas , Li Chao , Francis Lewis , Tzouros Manuel , Krijgsveld Jeroen , Holstege Frank C. P. , Conlan R. Steven
Published: February 2014

Significance

Mediator is a megadalton multisubunit molecular switchboard involved in gene regulation in eukaryotes and is structurally conserved between species. It bridges the general transcription machinery and function-specific DNA binding proteins. It plays a dynamic role in regulating a wide range of processes, involving, for example, thyroid and vitamin D receptors. The role of Mediator appears to be in the fine tuning of the activation and repression of gene expression in many organisms, yet the underlying mechanisms of how its own function is regulated remains to be unraveled. Here we demonstrate how Mediator autoregulates its own function by cross-talk between the tail module and the Cdk8 kinase module in an active process involving priming of the mediator component Med3 for ubiquitin-ligase (Grr1)–mediated degradation by Cdk8 phosphorylation.
Enhanced cognitive flexibility in reversal learning induced by removal of the extracellular matrix in auditory cortex
Authors: Happel Max F. K. , Niekisch Hartmut , Castiblanco Rivera Laura L. , Ohl Frank W. , Deliano Matthias , Frischknecht Renato
Published: February 2014

Significance

The brain’s extracellular matrix (ECM) mediates structural stability by enwrapping synaptic contacts fundamental for long-term memory storage. Whether the ECM in the adult brain might thereby govern learning-related plasticity, lifelong memory reformation, and higher cognitive functions is largely unknown. Here, we enzymatically degraded the ECM in the auditory cortex of adult Mongolian gerbils during a reversal learning task. Such local weakening of the structurally rigid ECM specifically accelerated strategy changes required for reversal learning. It neither affected general sensory learning nor erased already established, learned memory traces. Thus, ECM modulation might promote the cognitive flexibility that can build on learned behaviors, and has further implications to develop new tools for guided neuroplasticity with therapeutic potential.
Down-regulation of tricarboxylic acid (TCA) cycle genes blocks progression through the first mitotic division in
Caenorhabditis elegans
embryos
Authors: Rahman Mohammad M. , Rosu Simona , Joseph-Strauss Daphna , Cohen-Fix Orna
Published: February 2014

Significance

Cell division is driven by the cell cycle machinery, which responds in an unknown fashion to the metabolic and nutrient state of the cell. We uncovered a previously unknown link between the cell cycle machinery and the tricarboxylic acid (TCA) cycle (also known as the Krebs cycle), which forms intermediates required for ATP production and other anabolic pathways. We show that in
Caenorhabditis elegans
embryos, down-regulation of the TCA cycle inhibits entry into the first mitotic division by preventing the removal of inhibitory phosphorylation on cyclin-dependent kinase 1. Our data suggest that in the one-cell stage embryo, the cell cycle machinery is sensitive to the metabolic state of the cell, a phenomenon that may also exist in mammalian embryos.
Large-scale interaction profiling of PDZ domains through proteomic peptide-phage display using human and viral phage peptidomes
Authors: Ivarsson Ylva , Arnold Roland , McLaughlin Megan , Nim Satra , Joshi Rakesh , Ray Debashish , Liu Bernard , Teyra Joan , Pawson Tony , Moffat Jason , Li Shawn Shun-Cheng , Sidhu Sachdev S. , Kim Philip M.
Published: February 2014

Significance

Although knowledge about the human interactome is increasing in coverage because of the development of high-throughput technologies, fundamental gaps remain. In particular, interactions mediated by short linear motifs are of great importance for signaling, but systematic experimental approaches for their detection are missing. We fill this important gap by developing a dedicated approach that combines bioinformatics, custom oligonucleotide arrays and peptide-phage display. We computationally design a library of all possible motifs in a given proteome, print representatives of these on custom oligonucleotide arrays, and identify natural peptide binders for a given protein using phage display. Our approach is scalable and has broad application. Here, we present a proof-of-concept study using both designed human and viral peptide libraries.
The role of the hypervariable C-terminal domain in Rab GTPases membrane targeting
Authors: Li Fu , Yi Long , Zhao Lei , Itzen Aymelt , Goody Roger S. , Wu Yao-Wen
Published: February 2014

Significance

Rab GTPases are key regulators of intracellular vesicular transport in eukaryotic cells, for example in neurotransmission and endocytosis. Each of more than 60 Rabs in human cells regulates these processes at a specific subcellular membrane. The hypervariable C-terminal domain (HVD) of Rab has been proposed to contain a targeting signal, but recent studies have argued this model. However, the role of the Rab HVD and the mechanism of Rab membrane targeting remain elusive. In this study, using a combination of unique synthetic protein probes and cell biological tools, we dissect the role of the HVD for subcellular Rab targeting. We find that the HVD can act as a structurally flexible spacer, a subcellular localization determinant, and/or an enhancer of membrane affinity.
Transcription could be the key to the selection advantage of mitochondrial deletion mutants in aging
Authors: Kowald Axel , Kirkwood Thomas B. L.
Published: February 2014

Significance

Mitochondria, the powerhouses of the cell, possess their own DNA, which encodes proteins involved in cellular ATP production. During the aging process deleted versions of mtDNA accumulate inside cells and replace the wild type form. Currently no explanation exists that can explain the mechanism behind this accumulation, which is also compatible with experimental observations. We present here a new idea based on the distinctive connection between transcription and replication of mtDNA. Analysis of mtDNA deletion spectra strongly supports our hypothesis and computer simulations show the mechanism to be compatible with data from short- and long-lived species. We believe that this idea may provide a major breakthrough in understanding the complex links between mitochondrial mutations and their accumulation in aging.
Bidirectional thermotaxis in
Caenorhabditis elegans
is mediated by distinct sensorimotor strategies driven by the AFD thermosensory neurons
Authors: Luo Linjiao , Cook Nathan , Venkatachalam Vivek , Martinez-Velazquez Luis A. , Zhang Xiaodong , Calvo Ana C. , Hawk Josh , MacInnis Bronwyn L. , Frank Michelle , Ng Jia Hong Ray , Klein Mason , Gershow Marc , Hammarlund Marc , Goodman Miriam B. , Colón-Ramos Daniel A. , Zhang Yun , Samuel Aravinthan D. T.
Published: February 2014

Significance

The nematode
Caenorhabditis elegans
offers the opportunity to map complex behaviors to the specific roles of each neuron in a 302-neuron nervous system. Thermotaxis is a complex behavior where the worm inverts the behavioral mode—positive thermotaxis up gradients or negative thermotaxis down gradients—to move toward a remembered temperature. How are both long-term memory and multiple behavioral modes encoded? A long-standing model has been that separate circuits for positive and negative thermotaxis compete for control of body movement. In contrast, we find that different modes of thermotaxis are driven by one set of AFD thermosensory neurons. Circuits for different thermotactic behaviors diverge from the AFD neurons, probably by coupling sensory inputs to motor programs in different ways to create different thermotactic behaviors.
Ischemic neurons recruit natural killer cells that accelerate brain infarction
Authors: Gan Yan , Liu Qiang , Wu Wei , Yin Jun-Xiang , Bai Xue-Feng , Shen Rulong , Wang Yongjun , Chen Jieli , La Cava Antonio , Poursine-Laurent Jennifer , Yokoyama Wayne , Shi Fu-Dong
Published: February 2014

Significance

Stroke is a devastating illness second only to cardiac ischemia as a cause of death worldwide. Long-time attempts to salvage dying neurons and preserve neurological functions via various neuroprotective agents have failed, owing at least in part to medical science’s limited knowledge of ischemia-induced elements that participate in irreversible neurovascular damage. The present study was performed to understand the role of natural killer (NK) cells, a key member of the innate immune system, in stroke. We discovered that NK cells infiltrated the brains of stroke patients and mice with induced stroke. Multiple pathways by which NK cells exacerbate brain infarction are discovered. This study revealed the role of NK cells in the pathogenesis of stroke.
Mechanotransduction of fluid stresses governs 3D cell migration
Authors: Polacheck William J. , German Alexandra E. , Mammoto Akiko , Ingber Donald E. , Kamm Roger D.
Published: February 2014

Significance

Interstitial flow (IF) is elevated in solid tumors and imparts fluid stresses on tumor cells within the extracellular matrix (ECM), and these fluid stresses must be balanced by stress in matrix adhesions to maintain static equilibrium. This force balance results in greater matrix adhesion tension on the upstream side of the cell, and we demonstrate that this tension activates β1-integrin adhesion complexes, resulting in localization and activation of focal adhesion (FA) proteins near the upstream membrane. Importantly, we demonstrate that this asymmetric FA activation governs the direction of cell migration in 3D, and therefore our data show that mechanical stress acting on cells within a 3D ECM is a fundamental directional migratory stimulus.
Stability of mRNA influences osteoporotic bone mass via CNOT3
Authors: Watanabe Chiho , Morita Masahiro , Hayata Tadayoshi , Nakamoto Tetsuya , Kikuguchi Chisato , Li Xue , Kobayashi Yasuhiro , Takahashi Naoyuki , Notomi Takuya , Moriyama Keiji , Yamamoto Tadashi , Ezura Yoichi , Noda Masaki
Published: February 2014

Significance

Osteoporosis is a highly prevalent disease affecting nearly 20 million people in the United States and is life-threatening in elderly patients. However, underlying pathophysiology regarding the posttranscriptional control of bone resorption is incompletely understood. CNOT3 is a molecule involved in mRNA stability in yeast to mammalian cells, but its role in bone regulation is not known. We discovered that
Cnot3
deficiency specifically enhances receptor activator of NF-κB (RANK) mRNA stability and leads to osteopenia in healthy young adult animals. Moreover,
Cnot3
levels are reduced in ageing-induced osteoporosis, and
Cnot3
deficiency further exacerbates such osteoporosis significantly. As a mechanism,
Cnot3
binds to RANK mRNA and its 3′-UTR renders
Cnot3
-dependent instability to the reporter gene. Our results reveal
Cnot3
regulation in aging-induced osteoporosis.
Nuclear compartmentalization of odorant receptor genes
Authors: Armelin-Correa Lucia M. , Gutiyama Luciana M. , Brandt Débora Y. C. , Malnic Bettina
Published: February 2014

Significance

The mechanisms underlying odorant receptor (OR) monoallelic and monogenic expression are unclear. We show for the first time that the nuclei of olfactory neurons have a characteristic organization of facultative heterochromatin: it is highly concentrated around a large constitutive heterochromatin block located centrally in the nucleus. In addition, we show that the homologous alleles of a given OR gene are located in different chromatin compartments in the olfactory nucleus: while one of the alleles is associated with deeply repressed constitutive heterochromatin, the other one is located in or close to the more plastic facultative heterochromatin. This spatial organization is likely to be important for both the monoallelic and monogenic expression of these genes.
Trimethylamine
N
-oxide metabolism by abundant marine heterotrophic bacteria
Authors: Lidbury Ian , Murrell J. Colin , Chen Yin
Published: February 2014

Significance

Trimethylamine
N
-oxide (TMAO) is a nitrogen-containing osmolyte found in a wide variety of marine biota and has been detected at nanomolar concentrations in surface seawaters. This study provides the first genetic and biochemical evidence for uptake and catabolism of TMAO by marine heterotrophic bacteria that are abundant in the oceans. The genes conferring the ability of bacteria to catabolize TMAO we identified in this study are highly expressed in the marine environment and can be used as functional biomarkers to better understand oceanic microbial-mediated carbon and nitrogen cycles. Our data suggest that TMAO represents a significant, yet overlooked, nutrient for marine bacteria in the surface oceans.
Phosphorylation releases constraints to domain motion in ERK2
Authors: Xiao Yao , Lee Thomas , Latham Michael Parker , Warner Lisa Rose , Tanimoto Akiko , Pardi Arthur , Ahn Natalie G.
Published: February 2014

Significance

This paper uses NMR methods to compare the dynamics of a protein kinase in its active and inactive states. The results show that domain movements in the MAP kinase ERK2 are inherently constrained until the enzyme is activated by phosphorylation, with the constraint located at the hinge region. This represents an important mode for dynamical regulation in ERK2, not anticipated from previous X-ray structural analyses.
The tripartite motif coiled-coil is an elongated antiparallel hairpin dimer
Authors: Sanchez Jacint G. , Okreglicka Katarzyna , Chandrasekaran Viswanathan , Welker Jordan M. , Sundquist Wesley I. , Pornillos Owen
Published: February 2014

Significance

Tripartite motif or TRIM proteins make up the largest superfamily of RING-domain E3 ubiquitin ligases. These enzymes function in a wide variety of important cellular processes, particularly innate antiviral response mechanisms. Dimerization is critical for the function of many TRIM proteins. Here we show how TRIM25 dimerizes and demonstrate that this dimerization mode is apparently conserved across the entire TRIM protein family. Our results reveal how the dimerization domain positions the other TRIM effector domains to recognize and ubiquitylate substrates and how the TRIM5 family can form higher-order hexagonal assemblies that increase the avidity of substrate recognition.
Evaluating officially reported polycyclic aromatic hydrocarbon emissions in the Athabasca oil sands region with a multimedia fate model
Authors: Parajulee Abha , Wania Frank
Published: February 2014

Significance

Our study shows that emissions of polycyclic aromatic hydrocarbons estimated in environmental impact assessments conducted to approve developments in the Athabasca oil sands region are likely too low. This finding implies that environmental concentrations in exposure-relevant media, such as air, water, and food, estimated using those emissions may also be too low. The potential therefore exists that estimation of future risk to humans and wildlife because of surface mining activity in the Athabasca oil sands region has been underestimated.
MicroRNA-like viral small RNA from Dengue virus 2 autoregulates its replication in mosquito cells
Authors: Hussain Mazhar , Asgari Sassan
Published: February 2014

Significance

Dengue virus has emerged as one of the most significant arboviruses, affecting millions of people around the world. Here, we show the production of a functional microRNA-like small RNA encoded by Dengue virus, which negatively regulates virus replication by targeting the viral nonstructural protein 1 sequences. The report provides a comprehensive analysis of the biogenesis and function of the viral small RNA. The results also highlight the possibility of utilizing the small RNA in inhibiting at least three serotypes of the virus. The outcomes have a significant impact on our understanding of the biology of the virus (and flaviviruses in general) and small RNA biogenesis, and open up a potential avenue for the control of the virus.
Attachment of phycobilisomes in an antenna–photosystem I supercomplex of cyanobacteria
Authors: Watanabe Mai , Semchonok Dmitry A. , Webber-Birungi Mariam T. , Ehira Shigeki , Kondo Kumiko , Narikawa Rei , Ohmori Masayuki , Boekema Egbert J. , Ikeuchi Masahiko
Published: February 2014

Significance

Light-harvesting antenna are essential for photosynthetic systems, which comprise photosystems I and II (PSI and PSII, respectively). Phycobilisome (PBS) is a dominant and efficient antenna for PSII in cyanobacteria and some algae, whereas the attachment of PBS to PSI is a long-standing open question. We isolated a unique PBS–PSI supercomplex from a nitrogen-fixing cyanobacterium. Biochemical and spectral studies revealed that PBS is functionally connected to the PSI tetramer via a new universal connecting component. A pseudoatomic model explains the configuration of the PSI tetramer and how the PBS is connected to PSI. Such antenna may play an important role for light harvesting in PSI-driven cyclic electron transport to facilitate nitrogen fixation and other reactions.
Hypoxia-induced and calpain-dependent cleavage of filamin A regulates the hypoxic response
Authors: Zheng Xiaowei , Zhou Alex-Xianghua , Rouhi Pegah , Uramoto Hidetaka , Borén Jan , Cao Yihai , Pereira Teresa , Akyürek Levent M. , Poellinger Lorenz
Published: February 2014

Significance

The cellular response to hypoxia is regulated by hypoxia-inducible factor-1α and -2α (HIF-1α and -2α). We have discovered that filamin A (FLNA), a large cytoskeletal actin-binding protein, physically interacts with HIF-1α (but not with HIF-2α) and promotes tumor growth and angiogenesis. Hypoxia induces a calpain-dependent cleavage of FLNA to generate a fragment that enhances nuclear accumulation of HIF-1α and is corecruited to HIF-1α target promoters, resulting in enhanced gene expression. This mechanism helps to explain why FLNA is upregulated in certain tumors and offers opportunities in targeting the hypoxia signaling pathway therapeutically.
Mapping the molecular determinants of BRAF oncogene dependence in human lung cancer
Authors: Lin Luping , Asthana Saurabh , Chan Elton , Bandyopadhyay Sourav , Martins Maria M. , Olivas Victor , Yan Jenny Jiacheng , Pham Luu , Wang Mingxue Michelle , Bollag Gideon , Solit David B. , Collisson Eric A. , Rudin Charles M. , Taylor Barry S. , Bivona Trever G.
Published: February 2014

Significance

Oncogenic mutations in the BRAF kinase occur in 6–8% of nonsmall cell lung cancers (NSCLCs), but the biological and clinical relevance of these mutations is unclear. We uncovered mechanisms of resistance to BRAF inhibition in NSCLC using an integrated functional chemical genetics approach in human BRAF-mutant NSCLC cells and clinical specimens. Our results provide biological insights into the regulation of BRAF oncogene dependence and identify strategies to optimize outcomes in BRAF-mutant NSCLC patients.
Variation in
MPK12
affects water use efficiency in
Arabidopsis
and reveals a pleiotropic link between guard cell size and ABA response
Authors: Des Marais David L. , Auchincloss Lisa C. , Sukamtoh Emeline , McKay John K. , Logan Tierney , Richards James H. , Juenger Thomas E.
Published: February 2014

Significance

Water is essential for nearly all aspects of plant biology though, for many plants, water is a limited resource. Water use efficiency measures the ratio of photosynthetic carbon fixation to water lost via leaf transpiration and is a critical determinant of plant productivity in field environments. We identify a molecular variant that drives variation in water use efficiency between two natural genotypes of
Arabidopsis thaliana
. We show that two alleles, distinguished by a single substitution in a signaling protein, cause whole-plant differences in plant water relations via inducible and constitutive mechanisms. Furthermore, we show that the alleles respond differently to environmental cues, demonstrating the molecular basis of a gene-by-environment interaction in a trait of interest to plant breeders and ecologists.
Predicting risky choices from brain activity patterns
Authors: Helfinstein Sarah M. , Schonberg Tom , Congdon Eliza , Karlsgodt Katherine H. , Mumford Jeanette A. , Sabb Fred W. , Cannon Tyrone D. , London Edythe D. , Bilder Robert M. , Poldrack Russell A.
Published: February 2014

Significance

Previous studies have examined the neural correlates of risk, but it is unknown if patterns of brain activity can predict choices in risky decision-making. We used functional MRI data to predict choice behavior in subjects while they performed a naturalistic risk-taking task. We found choices on subsequent trials could be predicted with high accuracy when condensing each individual's brain activity to two values, indicating that choice behavior is encoded even in coarse activation patterns. A searchlight analysis demonstrated that choices can also be predicted based on localized activity patterns within neural networks involved in cognitive control. These regions show greater activation prior to safe choices than risky choices, suggesting that control systems play a key role in inhibiting risky choices.
Activating killer cell immunoglobulin-like receptor 2DS2 binds to HLA-A*11
Authors: Liu Jingxian , Xiao Ziwei , Ko Hui Ling , Shen Meixin , Ren Ee Chee
Published: February 2014

Significance

Killer cell immunoglobulin-like receptors (KIRs) function as key recognition elements in innate immunity. Structural information for inhibitory KIRs 2DL2, 2DL1, and 3DL1 in complex with their respective HLA ligands is available, but such data for activating KIRs are lacking. We report here the successful crystallization and solved structure of the activating KIR2DS2 in complex with HLA-A*11:01. The structure clearly explains the role of Tyr45, which has long puzzled KIR researchers because it differentiates KIR2DS2 from all inhibitory KIRs, and is now shown to bind Thr80 of HLA-A*11:01. Using KIR2DS2 tetramers to bind HLA on live cells, we also provide evidence that peptide sequence can affect KIR–HLA binding. Our data thus resolve a long-standing problem in KIR biology.
TRPM2 channels mediate acetaminophen-induced liver damage
Authors: Kheradpezhouh Ehsan , Ma Linlin , Morphett Arthur , Barritt Greg J. , Rychkov Grigori Y.
Published: February 2014

Significance

Acetaminophen overdose is the most common cause of acute liver failure and the leading cause of chronic liver damage requiring liver transplantation in developed countries. There are limited options for early treatment. Acetaminophen liver toxicity leads to the formation of reactive oxygen and nitrogen species which cause an increase in intracellular Ca
2+
and hepatocellular death. We show that acetaminophen-induced liver toxicity depends on Transient Receptor Potential Melanostatine 2 (TRPM2) cation channels in hepatocytes, which are activated in response to oxidative stress and are responsible for Ca
2+
overload. Lack of TRPM2 channels in hepatocytes or their pharmacological inhibition protects liver from acetaminophen toxicity. This provides evidence that TRPM2 may present a potential therapeutic target for treatment of oxidative-stress related liver diseases.
Evolution and selection of river networks: Statics, dynamics, and complexity
Authors: Rinaldo Andrea , Rigon Riccardo , Banavar Jayanth R. , Maritan Amos , Rodriguez-Iturbe Ignacio
Published: February 2014

Significance

Our focus is on a rich interdisciplinary problem touching on earth science, hydrology, and statistical mechanics—an understanding of the statics and dynamics of the network structures that we observe in the fluvial landscape, and their relation to evolution and selection of recurrent patterns of self-organization. It is an exemplar of how diverse ideas, numerical simulation, and elementary mathematics can come together to help solve the mystery of understanding a ubiquitous pattern of nature.
Odorant receptor-mediated sperm activation in disease vector mosquitoes
Authors: Pitts R. Jason , Liu Chao , Zhou Xiaofan , Malpartida Juan C. , Zwiebel Laurence J.
Published: February 2014

Significance

Mosquitoes use neuronal-expressed odorant receptors in their antennae to locate blood meal sources via chemical cues emitted by hosts. Although their expression in nonsensory tissues is known, the potential for odorant receptors to also mediate endogenous signaling events in insects has remained unexplored. In this study, we have identified a subset of odorant receptors showing transcript expression in the testes of the malaria mosquito,
Anopheles gambiae
. In addition, we provide functional evidence that the broadly conserved insect coreceptor, Orco, mediates flagellar activation in mosquito spermatozoa. These results are reminiscent of odorant receptor function in human sperm and may represent an intriguing example of convergent evolution.