bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure–function correlations in tyrosinases
Authors: Kanteev Margarita , Goldfeder Mor , Fishman Ayelet
Published: June 2015

Tyrosinases are metalloenzymes belonging to the type‐3 copper protein family which contain two copper ions in the active site. They are found in various prokaryotes as well as in plants, fungi, arthropods, and mammals and are responsible for pigmentation, wound healing, radiation protection, and primary immune response. Tyrosinases perform two sequential enzymatic reactions: hydroxylation of monophenols and oxidation of diphenols to form quinones which polymerize spontaneously to melanin. Two other members of this family are catechol oxidases, which are prevalent mainly in plants and perform only the second oxidation step, and hemocyanins, which lack enzymatic activity and are oxygen carriers. In the last decade, several structures of plant and bacterial tyrosinases were determined, some with substrates or inhibitors, highlighting features and residues which are important for copper uptake and catalysis. This review summarizes the updated information on structure–function correlations in tyrosinases along with comparison to other type‐3 copper proteins.
Teaching and Learning the Purpose of Evidence for Knowledge and Knowing
Authors: Kirch Susan A.
Published: June 2015

Evidence is a cultural tool for engaging in a variety of knowledge production practices including observation, inference making, argumentation, persuasion, and explanation. Identifying and using evidence, as called for in many learning standards, is necessary but not sufficient for understanding the concepts and purposes of evidence. Before identifying and using evidence, learners need to be engaged as researchers of knowledge production. It is only through studying evidence in the context of knowledge production that learning the processes and tools of this human activity becomes relevant to learners. By learning to identify and use evidence in the context of knowledge production students can build a deep understanding of the origins and purpose of evidence, which is necessary for generating intrinsic motives for critical use.
The complex of ASYMMETRIC LEAVES (AS) proteins plays a central role in antagonistic interactions of genes for leaf polarity specification in Arabidopsis
Authors: Machida Chiyoko , Nakagawa Ayami , Kojima Shoko , Takahashi Hiro , Machida Yasunori
Published: June 2015

Leaf primordia are born around meristem‐containing stem cells at shoot apices, grow along three axes (proximal–distal, adaxial–abaxial, medial–lateral), and develop into flat symmetric leaves with adaxial–abaxial polarity. Axis development and polarity specification of Arabidopsis leaves require a network of genes for transcription factor‐like proteins and small RNAs. Here, we summarize present understandings of adaxial‐specific genes, ASYMMETRIC LEAVES1 (AS1) and AS2. Their complex (AS1–AS2) functions in the regulation of the proximal–distal leaf length by directly repressing class 1 KNOX homeobox genes (BP, KNAT2) that are expressed in the meristem periphery below leaf primordia. Adaxial–abaxial polarity specification involves antagonistic interaction of adaxial and abaxial genes including AS1 and AS2 for the development of two respective domains. AS1–AS2 directly represses the abaxial gene ETTIN/AUXIN RESPONSE FACTOR3 (ETT/ARF3) and indirectly represses ETT/ARF3 and ARF4 through tasiR‐ARF. Modifier mutations have been identified that abolish adaxialization and enhance the defect in the proximal–distal patterning in as1 and as2. AS1–AS2 and its modifiers synergistically repress both ARFs and class 1 KNOXs. Repression of ARFs is critical for establishing adaxial–abaxial polarity. On the other hand, abaxial factors KANADI1 (KAN1) and KAN2 directly repress AS2 expression. These data delineate a molecular framework for antagonistic gene interactions among adaxial factors, AS1, AS2, and their modifiers, and the abaxial factors ARFs as key regulators in the establishment of adaxial–abaxial polarity. Possible AS1–AS2 epigenetic repression and activities downstream of ARFs are discussed. WIREs Dev Biol 2015, 4:655–671. doi: 10.1002/wdev.196

This article is categorized under:

Gene Expression and Transcriptional Hierarchies > Regulatory Mechanisms

Plant Development > Vegetative Development

Plant Development > Cell Growth and Differentiation
Antitumor activity of a rhenium (I)-diselenoether complex in experimental models of human breast cancer
Authors: Collery Philippe , Mohsen Ahmed , Kermagoret Anthony , Corre Samantha , Bastian Gérard , Tomas Alain , Wei Ming , Santoni François , Guerra Nadia , Desmaële Didier , d’Angelo Jean
Published: June 2015

Rhenium (I)-diselenother (Re-diselenoether) is a water soluble metal-based compound, combining one atom of rhenium and two atoms of selenium. This compound has been reported to exhibit marked activities against several solid tumor cell lines. We now disclose an improved synthesis of this complex. The Re-diselenoether showed a potent inhibitory effect on MDA-MB231 cell division in vitro, which lasted when the complex was no longer present in the culture. Re-diselenoether induced a remarkable reduction of the volume of the primitive breast tumors and of the pulmonary metastases without clinical signs of toxicity, in mice-bearing a MDA-MB231 Luc+ tumor, orthotopically transplanted, after a daily oral administration at the dose of 10 mg/kg/d. Interestingly, an antagonism was observed when cisplatin was administered as a single i.p. injection 1 week after the end of the Re-diselenoether administration. In an effort to gain insight of the mechanisms of action of Re-diselenoether complex, interaction with 9-methylguanine as a nucleic acid base model was studied. We have shown that Re-diselenoether gave both mono- and bis-guanine Re adducts, the species assumed to be responsible for the DNA intrastrand lesions.
Initial Surgical Treatment of Humeral Shaft Fracture Predicts Difficulty Healing when Humeral Shaft Nonunion Occurs
Authors: Konda Sanjit R. , Davidovitch Roy I. , Egol Kenneth A.
Published: June 2015

Background

Although most humeral nonunions are successfully treated with a single procedure, some humeral nonunions are more difficult to heal and require multiple procedures. Current literature does not provide evidence describing how the prognosis for surgical repair in patients who develop humeral diaphyseal nonunions may be affected by initial operative versus nonoperative treatment.

Questions/Purposes

The purpose of this study was to assess whether operative versus nonoperative treatment of acute humeral shaft fractures impacts outcome of subsequent repairs of humeral nonunions (NU) including the need for additional surgery and a comparison of pain relief (Visual Analogue Scale for pain) and functional outcome (Short Musculoskeletal Functional Assessment).

Methods

Thirty-four patients with humeral shaft nonunion were evaluated of which 15 patients had been treated operatively (OF), and 19 patients had been treated nonoperatively (NO) for their initial humerus shaft fracture. All patients underwent plating with autogenous bone graft or allograft ± bone morphogenic protein (BMP) 2 or 7 as their final NU repair surgery prior to healing. We compared functional outcome and pain for both cohorts and determined risk factors for requiring more than 1 nonunion repair surgery.

Results

The mean time of final follow-up was 14.7 ± 10.4 months. Thirty-three of 34 NUs (97.1%) healed. Patients who underwent OF of their original fracture were more likely to require more than 1 NU repair surgery (66.7 vs. 0%, p < 0.01). Of the 15 patients who underwent initial OF, 33.0% required 1 NU surgery, 33.0% required 2 NU surgeries, and 33.0% required 3 NU surgeries. Patients who underwent initial OF were more likely to require >6 months to achieve union (40.0 vs. 10.5%, p = 0.04). At final follow-up, there was no difference in functional outcome or pain scores. Initial OF was the only independent predictor of needing more than 1 NU repair surgery (OR 70.1 CI 2.8–1762.3) to achieve healing.

Conclusion

Humeral shaft nonunions following initial operative fixation of the index fracture is more resistant to achieving union when compared to nonunions forming after initial nonoperative treatment. When final healing is achieved, there is no difference in function or pain.
How firm innovativeness and unexpected product reliability failures affect profitability
Authors: Mackelprang Alan W. , Habermann Marco , Swink Morgan
Published: June 2015

This study examines relationships among a firm’s innovativeness, its unexpected product failure costs, and financial performance. When a firm chooses to develop more innovative products and processes, product reliability outcomes become more uncertain. These uncertainties in turn may lead to unexpected warranty claims costs, as well as other costs that can erode the advantages of an innovation leadership position. This study empirically tests these propositions using publically reported warranty and financial data from 2003 to 2013, representing 482 unique firms. Consistent with prior studies, our estimation of the direct effects of firm innovativeness on financial performance shows an inverted–u–shaped relationship. Importantly, we find that more innovative firms also experience more unexpected product failure costs, and, consistent with organizational information processing theory, the negative impacts of these costs on financial performance extend well beyond the direct costs associated with remediating warranty claims. Further, we find that this relationship is robust to differing levels of industry innovativeness. Hence, our study suggests that product failure risks associated with firm innovativeness are significant, and act to at least partially offset the financial benefits of innovation leadership. In addition, standard accounting for product warranty claims may substantially understate the true costs associated with product failures, which appear to generate significant SG&A, fixed asset, and inventory costs above and beyond direct warranty processing costs. Our study also demonstrates a novel usage of warranty claims data. We discuss the implications of these findings for both managers and researchers.
Fleeting Glory in a Wasteland: Wealth, Politics, and Autonomy in Northern Chad
Authors: Brachet Julien , Scheele Judith
Published: June 2015

In January 2012, a newderdé(traditional leader) of the Teda in northern Chad was officially appointed. Held in the Tibesti, a remote, notoriously unruly but strategically important part of the Sahara, the investiture ceremony was attended by Teda from throughout the country and neighboring Libya and Niger, as well as by an impressive number of Chadian civil servants and international diplomats. Yet the ceremony itself was short and messy. Similarly, the historical underpinnings of the institution of thederdéand the selection process were unclear, leaving much room for debate. This uncertainty appears to lie at the heart of the institution of thederdé. Far from a resurgence of “traditional authority” to make up for “state failure” or to partake in the restructuring of postcolonial states—as observed elsewhere on the African continent—the investiture ceremony confirmed the decentralized nature of Teda social organization and the absence of even attempted governance, both with regards to the Chadian state and local political institutions. What mattered from a local point of view were not long-term strategies of power and control, but rather the immediate and gloriously wasteful distribution of wealth. Admiring eyes were turned not toward thederdéor the state officials who appointed him, but instead toward high-ranking military officers, well-dressed urban Libyan Teda, and trans-border smugglers, models of rapid but often short-lived success. This provides a counterexample to the current emphasis on governance and power in the analysis of African states and politics.
VOLUME 31: HTA'S EVOLUTION: FROM CONSUMER TO HONEST BROKER TO ENGAGED COLLABORATOR
Authors: Ollendorf Daniel A.
Published: June 2015

In this issue, Facey and colleagues have eloquently summarized the product of the February 2015 HTAi Policy Forum discussion—the need for health technology assessment (HTA) to shift from a historically reactive role in both evaluating current evidence and requesting additional evidence generation to a more proactive role engaging with stakeholders to ensure that evidence produced is appropriate for any given intervention at different stages of the clinical development program. This makes logical a priori sense, of course, as proactive and engaged discussion is always superior to reactive and potentially adversarial interaction.
A Fast Gradual Fault Detection Method for Underwater Integrated Navigation Systems
Authors: Yi-ting Liu , Xiao-su Xu , Xi-xiang Liu , Tao Zhang , Yao Li , Yi-qing Yao , Liang Wu , Jin-wu Tong
Published: June 2015

Gradual fault detection is always an important issue in integrated navigation systems, and the gradual fault is the most difficult fault to detect. To detect gradual faults in a timely and precise manner in integrated navigation systems, the statistical concepts of the normalised residual mean and the sum of absolute residuals are introduced according to the characteristics of gradual system failure in this paper. The applicability of the improved residual χ2 detection method is discussed. Then, the gradual fault detection program based on the improved residual χ2 detection method is designed with the criterion of normalised residual mean and the sum of absolute residual. The simulation results and vehicle tests show that: 1) The residual of the failed sub-system can be calculated accurately with the improved residual χ2 detection method, which has strong applicability in gradual fault detection; 2) The gradual fault can be detected in a short time by using the normalised residual mean and the sum of absolute residual.
Transitionspsychiatrie der Adoleszenz und des jungen Erwachsenenalters
Authors: Mayr Michael , Kapusta Nestor D. , Plener Paul L. , Pollak Eva , Schulze Ulrike , Freyberger Harald J. , Fegert Jörg M.
Published: June 2015

Der Wechsel von der kindespsychiatrischen in die erwachsenenpsychiatrische Behandlung wird durch das Erreichen der Volljährigkeit gemeinhin festgelegt. Diese festgesetzte Altersgrenze wird jedoch den unterschiedlichen Entwicklungsständen und Reifungsgraden von jungen Erwachsenen im Alter von 16 bis 24 Jahren mit psychischen Störungen nicht gerecht. Neurologische Besonderheiten, psychische Störungen und die rechtliche Einordnung dieser distinkten Zeitperiode, derzeitige Bruchstellen im Übergang zwischen den Einrichtungen, sowie verschiedene Transitionsprogramme und Konzepte werden diskutiert.
Elektronische Tagebücher optimieren die Kognitive Verhaltenstherapie bei Krankheitsängsten: Eine randomisiert-kontrollierte Studie
Authors: Bailer Josef , Kerstner Tobias , Mier Daniela , Rist Fred , Diener Carsten , Bleichhardt Gaby , Witthöft Michael
Published: June 2015

Zentrale Komponenten in kognitiv-behavioralen Erklärungsmodellen der Hypochondrie und den daraus abgeleiteten Behandlungen sind eine selektive Aufmerksamkeitslenkung auf körperliche Empfindungen und ein katastrophisierender Symptominterpretationsbias. Wir untersuchten, ob sich die Effektivität einer störungsspezifischen Kognitiven Verhaltenstherapie (KVT) für Patienten mit Hypochondrie durch ein zusätzliches zweiwöchiges elektronisches Tagebuchtraining (TBT), das auf eine Korrektur der Symptominterpretationen abzielt, verbessern lässt. Zu diesem Zweck wurden 35 Patienten mit Hypochondrie randomisiert zwei Interventionsformen zugewiesen: Gruppe 1 (N = 16) erhielt vor der KVT (16 Einzelsitzungen) ein zweiwöchiges TBT unter therapeutischer Anleitung (4 Sitzungen). Gruppe 2 (N = 19) erhielt vor der KVT vier Therapiegespräche ohne TBT. Das Ausmaß der Krankheitsangst wurde mit dem Short Health Anxiety Inventory erfasst. Beide Gruppen zeigten nach der Therapie eine signifikante Reduktion der Krankheitsangst. In der Gruppe mit TBT verbesserte sich die Krankheitsangst jedoch schneller (d = .75) und stärker (d = .76) als in der Kontrollgruppe. Zudem zeigte die Gruppe mit TBT eine stärkere Habituation an bedrohliche Symptomstimuli als die Kontrollgruppe. Weitere Studien an größeren Stichproben sowie die Untersuchung von Langzeiteffekten sind notwendig, um die Wirksamkeit des vorgestellten TBT zu belegen.
Zidovudine, an anti-viral drug, resensitizes gemcitabine-resistant pancreatic cancer cells to gemcitabine by inhibition of the Akt-GSK3β-Snail pathway
Authors: Namba T , Kodama R , Moritomo S , Hoshino T , Mizushima T
Published: June 2015

Pancreatic cancer is one of the most difficult malignancies to treat owing to the rapid acquisition of resistance to chemotherapy. Gemcitabine, a first-line treatment for pancreatic cancer, prolongs patient survival by several months, and combination treatment with gemcitabine and other anti-cancer drugs in the clinic do not show any significant effects on overall survival. Thus, identification of a drug that resensitizes gemcitabine-resistant pancreatic cancer to gemcitabine and a better understanding of the molecular mechanisms of gemcitabine resistance are critical to develop new therapeutic options for pancreatic cancer. Here, we report that zidovudine resensitizes gemcitabine-resistant pancreatic cancer to gemcitabine as shown by screening a compound library, including clinical medicine, using gemcitabine-resistant cells. In analyzing the molecular mechanisms of zidovudine effects, we found that the epithelial-to-mesenchymal transition (EMT)-like phenotype and downregulation of human equilibrative nucleoside transporter 1 (hENT1) are essential for the acquisition of gemcitabine resistance, and zidovudine restored these changes. The chemical biology investigations also revealed that activation of the Akt-GSK3β-Snail1 pathway in resistant cells is a key signaling event for gemcitabine resistance, and zidovudine resensitized resistant cells to gemcitabine by inhibiting this activated pathway. Moreover, our in vivo study demonstrated that co-administration of zidovudine and gemcitabine strongly suppressed the formation of tumors by gemcitabine-resistant pancreatic cancer and prevented gemcitabine-sensitive pancreatic tumors from acquiring gemcitabine-resistant properties, inducing an EMT-like phenotype and downregulating hENT1 expression. These results suggested that co-treatment with zidovudine and gemcitabine may become a novel therapeutic strategy for pancreatic cancer by inhibiting chemoresistance-specific signaling.
Imaging an aligned polyatomic molecule with laser-induced electron diffraction
Authors: Pullen Michael G. , Wolter Benjamin , Le Anh-Thu , Baudisch Matthias , Hemmer Michaël , Senftleben Arne , Schröter Claus Dieter , Ullrich Joachim , Moshammer Robert , Lin C. D. , Biegert Jens
Published: June 2015

Laser-induced electron diffraction is an evolving tabletop method that aims to image ultrafast structural changes in gas-phase polyatomic molecules with sub-Ångström spatial and femtosecond temporal resolutions. Here we demonstrate the retrieval of multiple bond lengths from a polyatomic molecule by simultaneously measuring the C–C and C–H bond lengths in aligned acetylene. Our approach takes the method beyond the hitherto achieved imaging of simple diatomic molecules and is based on the combination of a 160 kHz mid-infrared few-cycle laser source with full three-dimensional electron–ion coincidence detection. Our technique provides an accessible and robust route towards imaging ultrafast processes in complex gas-phase molecules with atto- to femto-second temporal resolution.
Large Seebeck effect by charge-mobility engineering
Authors: Sun Peijie , Wei Beipei , Zhang Jiahao , Tomczak Jan M. , Strydom A.M. , Søndergaard M. , Iversen Bo B. , Steglich Frank
Published: June 2015

The Seebeck effect describes the generation of an electric potential in a conducting solid exposed to a temperature gradient. In most cases, it is dominated by an energy-dependent electronic density of states at the Fermi level, in line with the prevalent efforts towards superior thermoelectrics through the engineering of electronic structure. Here we demonstrate an alternative source for the Seebeck effect based on charge-carrier relaxation: a charge mobility that changes rapidly with temperature can result in a sizeable addition to the Seebeck coefficient. This new Seebeck source is demonstrated explicitly for Ni-doped CoSb3, where a marked mobility change occurs due to the crossover between two different charge-relaxation regimes. Our findings unveil the origin of pronounced features in the Seebeck coefficient of many other elusive materials characterized by a significant mobility mismatch. When utilized appropriately, this effect can also provide a novel route to the design of improved thermoelectric materials.
Exosomes released by keratinocytes modulate melanocyte pigmentation
Authors: Cicero Alessandra Lo , Delevoye Cédric , Gilles-Marsens Floriane , Loew Damarys , Dingli Florent , Guéré Christelle , André Nathalie , Vié Katell , van Niel Guillaume , Raposo Graça
Published: June 2015

Cells secrete extracellular vesicles (EVs), exosomes and microvesicles, which transfer proteins, lipids and RNAs to regulate recipient cell functions. Skin pigmentation relies on a tight dialogue between keratinocytes and melanocytes in the epidermis. Here we report that exosomes secreted by keratinocytes enhance melanin synthesis by increasing both the expression and activity of melanosomal proteins. Furthermore, we show that the function of keratinocyte-derived exosomes is phototype-dependent and is modulated by ultraviolet B. In sum, this study uncovers an important physiological function for exosomes in human pigmentation and opens new avenues in our understanding of how pigmentation is regulated by intercellular communication in both healthy and diseased states.
Digital microfluidic immunocytochemistry in single cells
Authors: Ng Alphonsus H. C. , Chamberlain M. Dean , Situ Haozhong , Lee Victor , Wheeler Aaron R.
Published: June 2015

We report a new technique called Digital microfluidic Immunocytochemistry in Single Cells (DISC). DISC automates protocols for cell culture, stimulation and immunocytochemistry, enabling the interrogation of protein phosphorylation on pulsing with stimulus for as little as 3 s. DISC was used to probe the phosphorylation states of platelet-derived growth factor receptor (PDGFR) and the downstream signalling protein, Akt, to evaluate concentration- and time-dependent effects of stimulation. The high time resolution of the technique allowed for surprising new observations—for example, a 10 s pulse stimulus of a low concentration of PDGF is sufficient to cause >30% of adherent fibroblasts to commit to Akt activation. With the ability to quantitatively probe signalling events with high time resolution at the single-cell level, we propose that DISC may be an important new technique for a wide range of applications, especially for screening signalling responses of a heterogeneous cell population.
Force-induced chemical reactions on the metal centre in a single metalloprotein molecule
Authors: Zheng Peng , Arantes Guilherme M. , Field Martin J. , Li Hongbin
Published: June 2015

Metalloproteins play indispensable roles in biology owing to the versatile chemical reactivity of metal centres. However, studying their reactivity in many metalloproteins is challenging, as protein three-dimensional structure encloses labile metal centres, thus limiting their access to reactants and impeding direct measurements. Here we demonstrate the use of single-molecule atomic force microscopy to induce partial unfolding to expose metal centres in metalloproteins to aqueous solution, thus allowing for studying their chemical reactivity in aqueous solution for the first time. As a proof-of-principle, we demonstrate two chemical reactions for the FeS4 centre in rubredoxin: electrophilic protonation and nucleophilic ligand substitution. Our results show that protonation and ligand substitution result in mechanical destabilization of the FeS4 centre. Quantum chemical calculations corroborated experimental results and revealed detailed reaction mechanisms. We anticipate that this novel approach will provide insights into chemical reactivity of metal centres in metalloproteins under biologically more relevant conditions.
Gender differences in brain structure and resting-state functional connectivity related to narcissistic personality
Authors: Yang Wenjing , Cun Lingli , Du Xue , Yang Junyi , Wang Yanqiu , Wei Dongtao , Zhang Qinglin , Qiu Jiang
Published: June 2015

Although cognitive and personality studies have observed gender differences in narcissism, the neural bases of these differences remain unknown. The current study combined the voxel-based morphometry and resting state functional connectivity (rsFC) analyses to explore the sex-specific neural basis of narcissistic personality. The VBM results showed that the relationship between narcissistic personality and regional gray matter volume (rGMV) differed between sexes. Narcissistic scores had a significant positive correlation with the rGMV of the right SPL in females, but not in males. Further analyses were conducted to investigate the sex-specific relationship between rsFC and narcissism, using right SPL/frontal eye fields (FEF) as the seed regions (key nodes of the dorsal attention network, DAN). Interestingly, decreased anticorrelations between the right SPL/FEF and areas of the precuneus and middle frontal gyrus (key nodes of the the default mode network, DMN) were associated with higher narcissistic personality scores in males, whereas females showed the opposite tendency. The findings indicate that gender differences in narcissism may be associated with differences in the intrinsic and dynamic interplay between the internally-directed DMN and the externally-directed TPN. Morphometry and functional connectivity analyses can enhance our understanding of the neural basis of sex-specific narcissism.
Heat stress induced apoptosis is triggered by transcription-independent p53, Ca2+ dyshomeostasis and the subsequent Bax mitochondrial translocation
Authors: Gu Z. T. , Li L. , WU F. , Zhao P. , Yang H. , Liu Y. S. , Geng Y. , Zhao M. , Su L.
Published: June 2015

In this study, We demonstrated that Bax mitochondrial translocation plays a vital role in the initiation of the mitochondrial signaling pathway upon activation by heat stress. In addition, both p53 mitochondrial translocation and Ca2+ signal mediated MPTP opening activate Bax mitochondrial translocation. Employing pifithrin-α (a p53 mitochondrial translocation inhibitor) and CsA (a permeability transition pore (MPTP) inhibitor), we found that heat stress induced Bax mitochondrial translocation was significantly inhibited in cells pretreated with both PFT and CsA. Furthermore, we demonstrated that generation of reactive oxygen species (ROS) is a critical mediator in heat stress induced apoptosis and that the antioxidant MnTBAP significantly decreased heat stress induced p53 mitochondrial translocation and Ca2+ signal mediated MPTP opening, as well as the subsequent Bax mitochondrial translocation and activation of the caspase cascade. Taken together, our results indicate that heat stress induces apoptosis through the mitochondrial pathway with ROS dependent mitochondrial p53 translocation and Ca2+ dyshomeostasis and the ensuing intro Bax mitochondrial translocation as the upstream events involved in triggering the apoptotic process observed upon cellular exposure to heat stress.
Scattering of Sculpted Light in Intact Brain Tissue, with implications for Optogenetics
Authors: Favre-Bulle Itia A. , Preece Daryl , Nieminen Timo A. , Heap Lucy A. , Scott Ethan K. , Rubinsztein-Dunlop Halina
Published: June 2015

Optogenetics uses light to control and observe the activity of neurons, often using a focused laser beam. As brain tissue is a scattering medium, beams are distorted and spread with propagation through neural tissue and the beam’s degradation has important implications in optogenetic experiments. To address this, we present an analysis of scattering and loss of intensity of focused laser beams at different depths within the brains of zebrafish larvae. Our experimental set-up uses a 488 nm laser and a spatial light modulator to focus a diffraction-limited spot of light within the brain. We use a combination of experimental measurements of back-scattered light in live larvae and computational modelling of the scattering to determine the spatial distribution of light. Modelling is performed using the Monte Carlo method, supported by generalised Lorenz–Mie theory in the single-scattering approximation. Scattering in areas rich in cell bodies is compared to that of regions of neuropil to identify the distinct and dramatic contributions that cell nuclei make to scattering. We demonstrate the feasibility of illuminating individual neurons, even in nucleus-rich areas, at depths beyond 100 μm using a spatial light modulator in combination with a standard laser and microscope optics.
Experimental Realization of Extreme Heat Flux Concentration with Easy-to-Make Thermal Metamaterials
Authors: Chen Fei , Yuan Lei Dang
Published: June 2015

The ability to harvest thermal energy and manipulate heat fluxes has recently attracted a great deal of research interest because this is critical to achieve efficient solar-to-thermal energy conversion in the technology of concentrated solar thermal collectors. Thermal metamaterials with engineered thermal conduction are often utilized to control the diffusive heat flow in ways otherwise not possible with naturally occurring materials. In this work, we adopt the transformation thermodynamics approach to design an annular fan-shaped thermal metamaterial which is capable of guiding heat fluxes and concentrating thermal energy to the central region of the metamaterial device without disturbing the temperature profile outside the structure – a fascinating and unique feature impossibly achieved with homogeneous materials. In experiment, this rationally-designed metamaterial structure demonstrates extreme heat flux compression from both line-shaped and point thermal sources with measured concentration efficiency up to 83.1%, providing the first experimental realization of our recent theoretical prediction (T. Han et al., Energy Environ. Sci., 2013, 6, 3537-3541). These unprecedented results may open up new possibilities for engineering thermal materials with desired properties that can be used for dramatically enhancing the efficiency of the existing solar thermal collectors.
iRhom1 regulates proteasome activity via PAC1/2 under ER stress
Authors: Lee WonJae , Kim YoungDoo , Park Jisu , Shim SangMi , Lee Jieun , Hong Se-hoon , Ahn Hye-Hyun , Lee Huikyong , Jung Yong-Keun
Published: June 2015

Proteasome is a protein degradation complex that plays a major role in maintaining cellular homeostasis. Despite extensive efforts to identify protein substrates that are degraded through ubiquitination, the regulation of proteasome activity itself under diverse signals is poorly understood. In this study, we have isolated iRhom1 as a stimulator of proteasome activity from genome-wide functional screening using cDNA expression and an unstable GFP-degron. Downregulation of iRhom1 reduced enzymatic activity of proteasome complexes and overexpression of iRhom1 enhanced it. Native-gel and fractionation analyses revealed that knockdown of iRhom1 expression impaired the assembly of the proteasome complexes. The expression of iRhom1 was increased by endoplasmic reticulum (ER) stressors, such as thapsigargin and tunicamycin, leading to the enhancement of proteasome activity, especially in ER-containing microsomes. iRhom1 interacted with the 20S proteasome assembly chaperones PAC1 and PAC2, affecting their protein stability. Moreover, knockdown of iRhom1 expression impaired the dimerization of PAC1 and PAC2 under ER stress. In addition, iRhom1 deficiency in D. melanogaster accelerated the rough-eye phenotype of mutant Huntingtin, while transgenic flies expressing either human iRhom1 or Drosophila iRhom showed rescue of the rough-eye phenotype. Together, these results identify a novel regulator of proteasome activity, iRhom1, which functions via PAC1/2 under ER stress.
Revealing patterns of local species richness along environmental gradients with a novel network tool
Authors: Baudena Mara , Sánchez Angel , Georg Co-Pierre , Ruiz-Benito Paloma , Rodríguez Miguel Á. , Zavala Miguel A. , Rietkerk Max
Published: June 2015

How species richness relates to environmental gradients at large extents is commonly investigated aggregating local site data to coarser grains. However, such relationships often change with the grain of analysis, potentially hiding the local signal. Here we show that a novel network technique, the “method of reflections”, could unveil the relationships between species richness and climate without such drawbacks. We introduced a new index related to potential species richness, which revealed large scale patterns by including at the local community level information about species distribution throughout the dataset (i.e., the network). The method effectively removed noise, identifying how far site richness was from potential. When applying it to study woody species richness patterns in Spain, we observed that annual precipitation and mean annual temperature explained large parts of the variance of the newly defined species richness, highlighting that, at the local scale, communities in drier and warmer areas were potentially the species richest. Our method went far beyond what geographical upscaling of the data could unfold and the insights obtained strongly suggested that it is a powerful instrument to detect key factors underlying species richness patterns and that it could have numerous applications in ecology and other fields.
The effect of land-use on the diversity and mass-abundance relationships of understory avian insectivores in Sri Lanka and southern India
Authors: Sreekar Rachakonda , Srinivasan Umesh , Mammides Christos , Chen Jin , Manage Goodale Uromi , Wimalabandara Kotagama Sarath , Sidhu Swati , Goodale Eben
Published: June 2015

Understory avian insectivores are especially sensitive to deforestation, although regional differences in how these species respond to human disturbance may be linked to varying land-use histories. South Asia experienced widespread conversion of forest to agriculture in the nineteenth century, providing a comparison to tropical areas deforested more recently. In Sri Lanka and the Western Ghats of India, we compared understory insectivores to other guilds and to insectivores with different vertical strata preferences, both inside mixed-species flocks and for the whole bird community. Overall species richness did not change across the land-use gradient, although there was substantial turnover in species composition between land-use types. We found that the proportion of species represented by insectivores was ~1.14 times higher in forest compared to agriculture and the proportion of insectivores represented by understory species was ~1.32 times higher in forests. Mass-abundance relationships were very different when analyzed on mixed-species flocks compared to the total community, perhaps indicating reduced competition in these mutualisms. We show that South Asia fits the worldwide pattern of understory insectivores declining with increased land-use intensity and conclude that these species can be used globally as indicator and/or umbrella species for conservation across different disturbance time scales.
Differential gene retention as an evolutionary mechanism to generate biodiversity and adaptation in yeasts
Authors: Morel Guillaume , Sterck Lieven , Swennen Dominique , Marcet-Houben Marina , Onesime Djamila , Levasseur Anthony , Jacques Noémie , Mallet Sandrine , Couloux Arnaux , Labadie Karine , Amselem Joëlle , Beckerich Jean-Marie , Henrissat Bernard , Van de Peer Yves , Wincker Patrick , Souciet Jean-Luc , Gabaldón Toni , Tinsley Colin R. , Casaregola Serge
Published: June 2015

The evolutionary history of the characters underlying the adaptation of microorganisms to food and biotechnological uses is poorly understood. We undertook comparative genomics to investigate evolutionary relationships of the dairy yeast Geotrichum candidum within Saccharomycotina. Surprisingly, a remarkable proportion of genes showed discordant phylogenies, clustering with the filamentous fungus subphylum (Pezizomycotina), rather than the yeast subphylum (Saccharomycotina), of the Ascomycota. These genes appear not to be the result of Horizontal Gene Transfer (HGT), but to have been specifically retained by G. candidum after the filamentous fungi–yeasts split concomitant with the yeasts’ genome contraction. We refer to these genes as SRAGs (Specifically Retained Ancestral Genes), having been lost by all or nearly all other yeasts and thus contributing to the phenotypic specificity of lineages. SRAG functions include lipases consistent with a role in cheese making and novel endoglucanases associated with degradation of plant material. Similar gene retention was observed in three other distantly related yeasts representative of this ecologically diverse subphylum. The phenomenon thus appears to be widespread in the Saccharomycotina and argues that, alongside neo-functionalization following gene duplication and HGT, specific gene retention must be recognized as an important mechanism for generation of biodiversity and adaptation in yeasts.
Achieving synchronization with active hybrid materials: Coupling self-oscillating gels and piezoelectric films
Authors: Yashin Victor V. , Levitan Steven P. , Balazs Anna C.
Published: June 2015

Lightweight, deformable materials that can sense and respond to human touch and motion can be the basis of future wearable computers, where the material itself will be capable of performing computations. To facilitate the creation of “materials that compute”, we draw from two emerging modalities for computation: chemical computing, which relies on reaction-diffusion mechanisms to perform operations and oscillatory computing, which performs pattern recognition through synchronization of coupled oscillators. Chemical computing systems, however, suffer from the fact that the reacting species are coupled only locally; the coupling is limited by diffusion as the chemical waves propagate throughout the system. Additionally, oscillatory computing systems have not utilized a potentially wearable material. To address both these limitations, we develop the first model for coupling self-oscillating polymer gels to a piezoelectric (PZ) micro-electro-mechanical system (MEMS). The resulting transduction between chemo-mechanical and electrical energy creates signals that can be propagated quickly over long distances and thus, permits remote, non-diffusively coupled oscillators to communicate and synchronize. Moreover, the oscillators can be organized into arbitrary topologies because the electrical connections lift the limitations of diffusive coupling. Using our model, we predict the synchronization behavior that can be used for computational tasks, ultimately enabling “materials that compute”.
Does the passage of seeds through frugivore gut affect their storage: A case study on the endangered plant Euryodendron excelsum
Authors: Shikang Shen , Fuqin Wu , Yuehua Wang
Published: June 2015

Plant-frugivore mutualism serves an important function in multiple ecological processes. Although previous studies have highlighted the effect of frugivore gut passage on fresh seed germinability, no study has investigated the effect on seed storage after frugivore gut passage. We used the endangered plant, Euryodendron excelsum, to determine the combined effects of frugivore gut passage and storage conditions on the germination percentage and rate of seeds. In particular, three treatments that included storage periods, storage methods and seed types were designed in the experiment. We hypothesized that seeds that passed through the gut will exhibit enhanced germination capacity and rate during storage. Results showed that the final germination percentage decreased in seeds that passed through the gut, whereas the germination rate increased during seed storage. Germination decreased in most types of seeds under both dry and wet storage after 6 months compared with storage after 1 and 3 months. The results suggest that after frugivore gut passage, E. excelsum seeds cannot form persistent soil seed bank in the field and were not suitable for species germplasm storage. These finding underscore that seeds that passed through frugivore gut have long-term impact on their viability and germination performance.
Function and evolution of Magnaporthe oryzae avirulence gene AvrPib responding to the rice blast resistance gene Pib
Authors: Zhang Shulin , Wang Ling , Wu Weihuai , He Liyun , Yang Xianfeng , Pan Qinghua
Published: June 2015

Magnaporthe oryzae (Mo) is the causative pathogen of the damaging disease rice blast. The effector gene AvrPib, which confers avirulence to host carrying resistance gene Pib, was isolated via map-based cloning. The gene encodes a 75-residue protein, which includes a signal peptide. Phenotyping and genotyping of 60 isolates from each of five geographically distinct Mo populations revealed that the frequency of virulent isolates, as well as the sequence diversity within the AvrPib gene increased from a low level in the far northeastern region of China to a much higher one in the southern region, indicating a process of host-driven selection. Resequencing of the AvrPiballele harbored by a set of 108 diverse isolates revealed that there were four pathoways, transposable element (TE) insertion (frequency 81.7%), segmental deletion (11.1%), complete absence (6.7%) and point mutation (0.6%), leading to loss of the avirulence function. The lack of any TE insertion in a sample of non-rice infecting Moisolates suggested that it occurred after the host specialization of Mo. Both the deletions and the functional point mutation were confined to the signal peptide. The reconstruction of 16 alleles confirmed seven functional nucleotide polymorphisms for the AvrPiballeles, which generated three distinct expression profiles.
Evaluation of multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) for sulfur metabolic studies using34S-labelled yeast
Authors: San Blas Oscar Galilea , Marchante Gayón Juan Manuel , García Alonso José Ignacio
Published: June 2015

A multi-collector ICP-MS instrument was evaluated for the on-line measurement of sulfur isotope ratios during the liquid chromatographic separation of sulfur metabolites in mouse urine after the oral administration of34S-labelled yeast.
Ion-precursor and ion-dose dependent anti-galvanic reduction
Authors: Tian Shubo , Yao Chuanhao , Liao Lingwen , Xia Nan , Wu Zhikun
Published: June 2015

Novel strategies to tune the composition, structure and properties of nanoparticles were achieved by varying the ion-precursor and ion-dose in anti-galvanic reduction.
Modulation of surface plasmon coupled emission (SPCE) by a pulsed magnetic field
Authors: Xie Kai-Xin , Cao Shuo-Hui , Liu Qian , Cai Wei-Peng , Huo Si-Xin , Watarai Hitoshi , Li Yao-Qun
Published: June 2015

The SPCE was modulated by a magnetic field through the interaction between plasmon and magnetic field.
Anti-Markovnikov hydroimination of terminal alkynes in gold-catalyzed pyridine construction from ammonia
Authors: Wang Liliang , Kong Lingbing , Li Yongxin , Ganguly Rakesh , Kinjo Rei
Published: June 2015

Gold-catalyzed hydroimination of terminal alkynes, giving rise to anti-Markovnikov adducts concomitant with unstable Markovnikov adducts is described.
Thermodynamic parameters of cation exchange in MOF-5 and MFU-4l
Authors: Brozek Carl K. , Dincă Mircea
Published: June 2015

We present a method for approximating thermodynamic parameters , ΔH, and ΔS for the cation exchange process in metal–organic frameworks, as exemplified by Ni2+ exchange into Zn4O(1,4-benzenedicarboxylate)3 (MOF-5) and Co2+ exchange into MOF-5 and Zn5Cl4(bis(1H-1,2,3-triazolo-[4,5-b],[4′,5′-i])dibenzo-[1,4]-dioxin)3 (MFU-4l).
Thermo-solutal and kinetic regimes of an anisotropic dendrite growing under forced convective flow
Authors: Alexandrov Dmitri V. , Galenko Peter K.
Published: June 2015

A new selection criterion for the stable mode of anisotropic dendrite growing under forced convective flow in thermo-solutal and kinetic regimes is obtained.
Hydrogen-bond acidity of ionic liquids: an extended scale
Authors: Kurnia Kiki A. , Lima Filipa , Cláudio Ana Filipa M. , Coutinho João A. P. , Freire Mara G.
Published: June 2015

Through the combination of experimental and theoretical approaches, a new extended scale for the hydrogen-bonding acidity of ionic liquids is provided.
Ni and/or Ni–Cu alloys supported over SiO2catalysts synthesized via phyllosilicate structures for steam reforming of biomass tar reaction
Authors: Ashok J. , Kathiraser Y. , Ang M. L. , Kawi S.
Published: June 2015

In this paper, we describe the synthesis of Ni/SiO2and Ni–Cu/SiO2catalysts derived from phyllosilicate structures (Ni/SiO2Pand Ni–Cu/SiO2P, respectively) for steam reforming of biomass tar reaction.
Carbon nanomaterials rescue phenanthrene toxicity in zebrafish embryo cultures
Authors: Falconer Jonathan L. , Jones Clinton F. , Lu Shan , Grainger David W.
Published: June 2015

Carbon nanomaterials rescued zebrafish embryos from phenanthrene toxicity.
RNAi therapeutics for brain cancer: current advancements in RNAi delivery strategies
Authors: Malhotra Meenakshi , Toulouse André , Godinho Bruno M. D. C. , Mc Carthy David John , Cryan John F. , O'Driscoll Caitriona M.
Published: June 2015

Delivering advanced therapies for brain cancer based on RNAi.
A battery-operated portable handheld electrospinning apparatus
Authors: Xu Shi-Cong , Qin Chong-Chong , Yu Miao , Dong Rui-Hua , Yan Xu , Zhao Hui , Han Wen-Peng , Zhang Hong-Di , Long Yun-Ze
Published: June 2015

A battery-operated handheld electrospinning apparatus with high safety, good performance and promising application.
Highly selective and sensitive nanoprobes for cyanide based on gold nanoclusters with red fluorescence emission
Authors: Zhang Guomei , Qiao Yunyun , Xu Ting , Zhang Caihong , Zhang Yan , Shi Lihong , Shuang Shaomin , Dong Chuan
Published: June 2015

A l-amino acid oxidase (LAAOx) capped gold nanocluster (LAAOx@AuNCs) fluorescent probe was used for rapid, highly selective and sensitive detection of CN−.
A graphene based tunable terahertz sensor with double Fano resonances
Authors: Zhang Yuping , Li Tongtong , Zeng Beibei , Zhang Huiyun , Lv Huanhuan , Huang Xiaoyan , Zhang Weili , Azad Abul K.
Published: June 2015

We propose a tunable terahertz (THz) sensor consisting of a subwavelength graphene disk and an annular gold ring within a unit cell.
Recent developments in 2D layered inorganic nanomaterials for sensing
Authors: Kannan Padmanathan Karthick , Late Dattatray J. , Morgan Hywel , Rout Chandra Sekhar
Published: June 2015

A comprehensive overview on the recent developments in the application of 2D layered inorganic nanomaterials as sensors is presented. Salient features of 2D materials in different sensing applicationsviz.gas sensing, electrochemical sensing, SERS and biosensing and photodetection are discussed.
An ordered mesoporous Ag superstructure synthesized via a template strategy for surface-enhanced Raman spectroscopy
Authors: Tian Cuifeng , Li Jiang , Ma Chunsheng , Wang Ping , Sun Xiaohong , Fang Jixiang
Published: June 2015

Ordered mesoporous Ag superstructure was synthesized by means of a nanocasting process. The nanowire bundled superstructure shows uniform distribution of small nanogap size down to ∼2 nm, thus exhibits ultrahigh Raman enhancement.
1,3-Dipolar cycloadditions of azomethine imines
Authors: Nájera Carmen , Sansano José M. , Yus Miguel
Published: June 2015

Azomethine imines react with alkenes and alkynes to give pyrazolines, pyrazolidines, pyrazolopyridines, indazoloisoquinolines, pyrazolo[1,5-a]isoquinolines and pyrazolopyrazolones through regio-, stereo- and enantioselective 1,3-dipolar cycloadditions.