bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the mechanical and wear behaviour of aluminium alloy with homogeneous and functionally graded silicon nitride composites
Authors: Radhika N.
Published: September 2016

Homogeneous and functionally graded LM25 aluminium (Al) composites were fabricated by incorporating silicon nitride (10 wt%, 40 µm) particles through liquid metallurgy and centrifugal casting, respectively. The performance of these composites was compared with unreinforced alloy. The microstructural behaviour of the surfaces of unreinforced alloy, homogeneous composite and functionally graded composite (outer, middle and inner surfaces) were examined through optical microscopy. These surfaces were also evaluated for mechanical properties. An abrasive wear test was conducted on all these surfaces to determine their effect on wear rate. The microstructural results revealed a particle-rich region at the outer surface of the functionally graded composite material and uniform dispersion of reinforcement particles in the homogeneous composite. The outer region of the functionally graded composite showed greater hardness and the homogeneous composite displayed higher tensile strength. The abrasive wear rate increased with an increase in load and decreased with an increase in speed, and the particle-rich outer surface showed a lower wear rate. Scanning electron microscopy analysis revealed a particle-rich outer surface of functionally graded composite with fewer scratches. Therefore, higher wear resistance was observed at the outer periphery of functionally graded composites and this property can be well-utilised in automotive tribo-components such as in cylinder liners for improved performance.
A model on the curved shapes of unsymmetric laminates including tool-part interaction
Authors: Yuan Zhenyi , Wang Yongjun , Wang Junbiao , Wei Shengmin , Liu Tianjiao , Cai Yujin , He Junjie , Wang Wang
Published: September 2016

The room-temperature shape of unsymmetric laminate due to the residual stress developed during the curing process has been investigated in the past decades. The factors influencing the residual stress of unsymmetric laminate, including moisture, fiber orientation, aspect ratio and ply thickness, have been widely investigated. Another mechanism that can generate residual stress is the interaction between the tool and the composite part during heating-up process. In this work, the effects resulting from the interaction between laminate and tool during the heating-up phase were considered. By introducing an interfacial shear stress due to tool-part interaction, an analytical model based on the Extended Classical Lamination Theory of Dano and Hyer was proposed to predict the room-temperature shapes of cross-ply unsymmetric laminates. The interfacial shear stress, which was correlated with experimental results, was introduced to tailor the amount of residual stress transferred from the tool. The model was validated with experimental data provided in the literature. It is shown that this model which takes the tool-part interaction into consideration could predict part processing deformations more accurately.
An investigation on dry sliding wear behaviour of pressure infiltrated AA1050-XMg/B4C composites
Authors: Cevik Engin , Sun Yavuz , Turen Yunus , Ahlatci Hayrettin
Published: September 2016

In this study, the effect of Mg alloying addition (1–4 wt.%) on dry sliding wear behaviour of AA1050 matrix composites was investigated. Composites were produced by the pressure infiltration technique at 800°C and had a B4C particle volume fraction of 60%. Reinforcement particles were uniformly distributed in the aluminium matrix. Compared with the AA1050 matrix, the weight loss of the composites decreased with increasing Mg content. The wear rate of the composites increased when the applied load and sliding distance were increased. The results show that when the applied load reaches critical values (30 N), the weight loss increases significantly.
Effect of modified layered double hydroxide on the flammability and mechanical properties of polypropylene
Authors: Zoromba Mohamed Sh. , Nour Mohamed A. , Eltamimy Hussam E. , Abd El-Maksoud Samir A.
Published: September 2016

Copper-aluminum layered double hydroxides (Cu-LDHs) and nickel-aluminum layered double hydroxides (Ni-LDHs) were synthesized using co-precipitation method. LDHs were organically modified by long chain sodium stearate. Polypropylene (PP)/layered double hydroxides (LDHs) and polypropylene (PP)/organically-modified layered double hydroxides (m.Cu-LDHs or m.Ni-LDHs) were prepared through the melt bending of the PP with either nanosized LDHs or m.LDHs without any other additives. The effect of stearate on the dispersibility of LDHs was investigated by X-ray diffraction (XRD). The surface morphology of LDHs was also studied using scanning electron microscope (SEM), and the thermal stability properties of PP/LDHs composites were studied by thermogravimetric analysis (TGA). The mechanical properties of the PP/LDH composites, tensile strength, and modulus of elasticity were investigated. The flammability properties were investigated using the cone calorimeter test. The intercalation of modified LDHs was determined by XRD in the presence of stearate. Results showed that modified LDHs presented good disperasbility in the PP matrix. The thermal stability of PP has been improved by up to 6% using m.Ni-LDHS. Unmodified and modified nanosized LDHs decreased the fire growth rate of PP from 10.8 kW/m2.s to 4.1 kW/m2.s and 4.5 kW/m2.s, respectively.
Modellbasierte Bestimmung der zeitabhängigen Eingangsleistung von Solarzellen für das Energiemanagement drahtloser Sensorsysteme
Authors: Viehweger Christian , Kanoun Olfa
Published: September 2016

Für einen kontinuierlichen Betrieb von solarzellenbasierten drahtlosen Sensorsystemen wird ein intelligentes
Energiemanagement benötigt. Damit die Verteilung der eingehenden Leistung zwischen Speichern und Last optimal erfolgen
kann, ist eine Voraussage des Energieverlaufs notwendig, wodurch sich die bestmögliche Ausnutzung der Leistung planen
lässt. Prognosemodelle nach dem Stand der Technik sind aufgrund ihrer hohen Anforderungen an Speicher, Rechenleistung und
Eingangsparameter nicht für den Betrieb auf Ultra-low-power‐Systemen geeignet. Im Rahmen dieser Veröffentlichung wird ein
Verfahren beschrieben, welches auf drahtlosen Sensorknoten eingesetzt werden kann und eine bessere Planung von
Betriebszuständen ermöglicht.
SSDCα – Inherently robust integrated biomimetic sensor-to-spike-to-digital converter based on peripheral neural ensembles
Authors: Kammara S. Abhaya Chandra , König Andreas
Published: September 2016

Rethinking analog to digital conversion has become extremely crucial in the race towards aggressively scaled technology
nodes with decaying signal swings. The concept of more recent TDCs, which are completely designed in digital domain, make
them simpler, easier to manufacture and faster to market. In previous work, LUCOS

J. Doge,
G. Schonfelder, G. Streil, and A. Konig. An HDR CMOS image sensor with spiking pixels, pixel-level ADC, and linear
characteristics. Circuits and Systems II: Analog and Digital Signal Processing, IEEE Transactions on,
49(2):155–158, Feb 2002.

, a high dynamic range image sensor using spike based processing with high pixel uniformity had
been designed. This motivated a generic ADC concept, which makes use of spike processing, to design a highly effective
sensor signal processing system, which carries the promise of robustness to technology scaling, for effective use in IoT
and Industrie 4.0. In this work, an ADC concept based on acoustic localization in biological sensory systems has been
pursued. An ADC has been designed based on this concept using biological models of spiking neurons. The first
proof-of-concept prototype chip SSDCα has been designed in ams 350 nm technology node with area of the
chip is 8.5 mm2, sampling rate from DC to 150 kHz, resolution from 8-bit to 13-bit, with
28, 200 transistors, 263 neurons and 517 synapses. The future work will move from 350 nm to
90 nm technology node to show the
improvement and robustness of the SSDC with technology scaling.
Isolation, identification of yeast strains producing bioethanol and improvement of bioethanol production on cheese whey / Biyoetanol üreten maya türlerinin izolasyonu, tanılaması ve peynir altı suyunda biyoetanol üretiminin sağlıklaştırılması
Authors: Boudjema Khaled , Fazouane-naimi Fethia , Hellal Amina
Published: September 2016

Objective: In this study, bioethanol production on cheese whey (prehydrolysed enzymatically using β galactosidase by isolated yeast strains was investigated.

Methods: The yeast strains were isolated from Algerian natural sources (soil and grape) and further were selected on the basis of high ethanol tolerance and high ethanol production on prehydrolysed cheese whey. The selected ones were identified by morphological, physiological and biochemical characteristics. Then, a molecular identification was carried out by amplification and sequencing the D1/D2 domain of 26S rDNA region. In addition, the operating parameters of fermentation such as temperature, pH and substrate concentration (mixture of glucose and galactose) were tested for efficient yeast strain.

Results: Among the selected and identified yeast strains, three strain isolates were found to be able to produce bioethanol. These strains are Hanseniaspora opuntiae Z087A0VS, Candida tropicalis Z087B0VS and Candida tropicalis Z087D0VS with an identity of 99% and 100% respectively comparing with the stocked strains in data bank. Furthermore, Hanseniaspora opuntiae presents an ethanol tolerance ethanol up to 11% whereas the two other strains of Candida tolerate up to 12%. The fermentation parameters of most efficient strain were optimized, the temperature 30°C, pH 5 and sugar concentration (glucose and galactose) of 12.5% (w/v) are considered as optimum values for Candida tropicalis Z087B0VS.

Conclusion: Candida tropicalis Z087B0VS can be considered as a good candidature for industrial bioethanol production.
Investigation on salt bridge interactions of mammalian prion proteins by molecular dynamics simulation / Memeli prion proteinlerinin moleküler dinamik simulasyon ile tuz köprüleri etkileşimlerinin araştırılması
Authors: Chen Xiliang , Chen Xin , Liu Yafang
Published: September 2016

Objective: Salt bridge interaction is one of the most important electrostatic interactions to stabilize the secondary and tertiary structures of protein. To obtain more insight into the molecular basis of prion proteins, the salt bridge networks in two animal prion proteins are studied in this work.

Methods: Molecular dynamics (MD) and Flow MD (FMD) simulations are employed to investigate the salt bridges interactions of rabbit prion protein (rPrPc), Syrian hamster prion protein (syPrPc) and the variants of the two prion proteins.

Results: The dynamic behaviors of salt bridges are characterized, and the relation between salt bridge interactions and local structures are also discussed. The type of salt bridges in the two prion proteins is divided into the helixloop, intra-helix and inter-helix salt bridges. It is found that the helix-loop salt bridges is more important for the stability of prion proteins than the other two kinds of slat bridge.

Conclusion: The Asp201-Arg155 (rS1), Asp177-Arg163 (rS3) and Asp178-Arg164 (syS1) are the important salt bridges to stabilize the structures of rPrPc and syPrPc, respectively. The structural stability is partly depended on the number of helix-loop salt bridge.
Diyabetik sıçanların karaciğer ve böbrekleri üzerinde Caralluma tuberculata’nın hipoglisemik ve hipolipidemik etkisi ve güvenliği / Liquidambar orientalis Mill. reçine ekstraktlarının antioksidan, sitotoksik ve iNOS aktiviteleri
Authors: Nalbantsoy Ayşe , Karış Mert , Karakaya Leyla , Akgül Yurdanur
Published: September 2016

Objective: The aim of this study is to investigate the in vitro cytotoxicity and iNOS (inducible nitric oxide synthase) inhibitory, and antioxidant activity in order to assess the traditional usage of Liquidambar orientalis Mill resin extract.

Methods: Different solvent extracts of Liquidambar orientalis Mill resin were prepared. The cytotoxicity of extracts was determined using MTT (3-(4,5-dimethyl-2-thiazolyl)- 2,5-diphenyl-2H-tetrazoliumbromide) assay. HeLa (Human cervix adenocarcinoma), A-549 (Human alveolar adenocarcinoma), MCF-7 (Human breast adenocarcinoma), CaCo-2 (Human colon colorectal adenocarcinoma), mPANC96 (Human pancreas adenocarcinoma), PC-3 (Human prostate adenocarcinoma), U87MG (Human glioblastoma- astrocytoma) and as a normal cell line HEK293 (Human embryonic kidney cells) and Vero (African green monkey kidney epithelial cells) were used for testing cytotoxicity. RAW 264.7 (murine macrophage cell lines) was used to determine the inhibition levels of inducible nitric oxide synthase (iNOS). HL-60 (human acute myeloid leukemia) was used to determine antioxidant activity as DCF production per cent.

Results: Hexane, dichloromethane, methanol and water extracts were prepared, and their iNOS inhibitory, cytotoxic and antioxidant activity were investigated. The estimated IC50 values of extracts varied from 6.68 to 48.90 μg/ ml after treatment with different doses of extracts for 48 h. Inhibition of the hexane, dichloromethane, methanol, and water extracts on LPS-induced NO production in RAW 264.7 macrophage were showed that the all extracts inhibited NO production in activated RAW 264.7 cells, except methanol extract. Hexane, dichloromethane and methanol extracts inhibited NO production with IC50 values of 22 μg/ml, 22 μg/ml, and 21/ml μg, respectively. The antioxidant activity was determined by the production of DCF in HL-60 cells. The extracts showed a potent antioxidant effect, with an IC50 of in between from 19.01 to 39.77 μg/ml.

Conclusion: This study is the first report showing the potential of Liquidambar orientalis Mill resin extracts for cytotoxicity, iNOS inhibition and the antioxidant activity as an alternative therapeutic approach for traditional uses. The results demonstrated that Liquidambar orientalis dichloromethane resin extracts showed strongest cytotoxic effect while all extracts except methanolic extracts exhibited moderate iNOS inhibition. All extracts other than hexane have a potent antioxidant effect in the cellular-based assay. In conclusion, further studies should focus on the purification of the active components of this extracts and to investigate the possible mode of action to obtain a better understanding of their potential use as cytotoxic, anti-inflammatory and antioxidant agents.
The effects of caffeine on the renal antioxidant activity in rats / Ratlarda böbrek antioksidan aktivitesi üzerine kafeinin etkileri
Authors: Demir Ebru Ofluoğlu , Demirtaş Canan Yılmaz , Paşaoğlu Özge Tuğçe
Published: September 2016

Objective: In our study, the short-term effects of caffeine on the renal antioxidant activity in rats were investigated.

Methods: Caffeine was given orally at two different doses: 30 mg/kg and 100 mg/kg (a high non-toxic dose). The current study included 30 rats, which were divided into 3 groups: a control group and two caffeine-treated groups. Group 1 was given caffeine at 30 mg/kg and Group 2 was given caffeine at 100 mg/kg for 14 days. We measured advanced oxidation protein products (AOPP), malondialdehyde (MDA) and nitric oxide (NO) levels in the kidney tissue following caffeine administration. In addition, we also evaluated superoxide dismutase (SOD), and glutathione S transferase (GST) activities in the kidney tissue.

Results: Our results showed that caffeine administration decreased lipid peroxidation and advanced oxidation protein products in kidney. Especially, MDA levels in the kidney tissue of the caffeine-treated groups decreased significantly as a result of the dose. NO levels in the kidney tissue of the caffeine-treated groups were higher than those in the control group. GST activities in the kidney tissue of rats in the caffeine groups also increased significantly. In our study, we did not observe significant changes in renal SOD activities upon caffeine consuption.

Conclusion: These results show that short-term consumption of two different doses of caffeine may protect against oxidative stress in the kidney tissue of rats. This effect is related to the caffeine dosage. Determining the mechanisms and antioxidant effects of caffeine at suitable dose requires advanced animal and human studies.
The Catalogue of Romanian Sphecidae (Hymenoptera: Apoidea: Sphecidae) from the Collection of “Grigore Antipa” National Museum of Natural History (Bucharest)
Authors: Levărdă Alexandra Florina , Matache Ioana
Published: September 2016

This catalogue presents data on 15 Romanian sphecid wasp species (Hymenoptera: Apoidea: Sphecidae) preserved in the Hymenoptera Collection of “Grigore Antipa” National Museum of Natural History, Bucharest. The collecting data, general distribution, distribution in Romania and some ecological aspects are provided for each species.
First Record of the Dacetine Ant Strumigenys argiola (Emery, 1869) (Hymenoptera: Formicidae) from Romania
Authors: Tăuşan Ioan , Pintilioaie Alexandru
Published: September 2016

The Romanian ant fauna is poorly known. It seems that many cryptic and parasitic species are missing from the checklist, including species with their ranges primarily outside of the Mediterranean. Herein,Strumigenys argiola(Emery, 1869) is a newly recorded species for the ant fauna of Romania, one male being collected in North–Eastern Romania.Strumigenys argiolalives in the soil, and hunts for small arthropods. For the time being, a total of 112 ant species are known from Romania.
Bird Fauna Diversity and Habitat Evolution in Jijioara River Valley (Romania)
Authors: Gache Carmen
Published: September 2016

We present our five years fieldworks’ results on the birds’ diversity and seasonal presence, including breeding birds’ populations on the Jijioara River valley that represent part of ROSPA0042 Ponds of Jijia and Miletin rivers. We recorded 129 bird species, including some rare breeding species in Romania like Platalea leucorodia, Recurvirostra avosetta, Himantopus himantopus, including two globally threatened species Aythya nyroca and Crex crex, all of them being recorded with small number of breeding pairs in the area. During the passage, hundreds of individuals of waterfowls present and waders are present on the suitable feeding areas. In the western part of the site, we found a very high level of habitats’ degradation, while the birds’ diversity and effectives were presenting a constant negative trend during our study period.
Contributions to the Knowledge on the Amphibians and Reptiles of Teleorman County (Southern Romania)
Authors: Iftime Alexandru , Iftime Oana
Published: September 2016

The results of faunistical surveys of the amphibians in Teleorman county (Southern Romania) are presented here; we have identified nine amphibian species (Triturus cristatus, Lissotriton vulgaris, Bombina bombina, Pelobates syriacus, P. fuscus, Bufo bufo, B. viridis, Hyla arborea, Rana dalmatina, Pelophylax ridibundus), two amphibian hybrids (Triturus cristatus × T. dobrogicus and Pelophylax kl. esculentus) and six reptile species (Emys orbicularis, Lacerta agilis, L. viridis, Podarcis tauricus, Natrix natrix, Dolichophis caspius), with new records for many of these.
Fundamental theoretical and practical investigations of the polymorph formation of small amphiphilic molecules, their co-crystals and salts
Authors: Martin Thomas , Niemietz Paul , Greim Dominik , Ectors Philipp , Senker Jürgen , Zahn Dirk , Breu Josef
Published: September 2016

The amphiphilic nature of benzoic acid, benzoates and benzamide causes an unexpected rich polymorphism. Featuring rather rigid and small molecular structures these compounds are ideal model systems for gaining a more fundamental understanding of molecular polymorphism by systematic and concerted investigations. The hydrophilic head allows for hydrogen bonding while the phenyl moiety gives rise to various π-stacking modes. Variations of hydrogen bonding versus π-stacking modes give rise to four polymorphs of benzamide. The central synthon in all phases is a dimer where hydrophilic units form double hydrogen bonds. As suggested by MD simulations of the nucleation process, variations of the crystallization conditions trigger whether the first self-assembly occurs via the hydrophilic head or the hydrophophic tail groups. Based on NMR crystallographic investigations for the co-crystallization of benzamide with benzoic acid, we observed yet another variation of the balance of the two dominating intermolecular interactions leading to the formation of a 1:1 co-crystal. The average crystal structure resembles the packing motive of pure benzoic acid with alternating ribbons of homogenous benzamide and benzoic acid dimers. For alkali-benzoate salts a coordination dilemma arises that is of general importance for many active pharmaceutical ingredients (APIs). A 1:1 stoichiometry requires condensation of coordination polyhedra of small inorganic cations which in turn causes steric stress that varies with the relative volumes of cation and anion. Interestingly, one way of resolving the dilemma is microphase separation which is directly related to the amphiphilic character of benzoate.
New lupan-type triterpenoids
Authors: Mkounga Pierre , Maza Hermine L.D. , Ouahouo Blandine M.W. , Tyon Lydie N. , Ishikawa Hayato , Nishino Hiroshi , Nkengfack Augustin E.
Published: September 2016

Three new lupan-type triterpernoid derivatives, namely globimetulin A (1), B (2) and C (3), were isolated from the shoot of Globimetula dinklagei (Loranthaceae), a hemiparasitic plant growing on Manihot esculenta, along with five known compounds: friedelin (4), friedelan-3-ol (5), 28-hydroxyfriedelin (6), 4-hydroxy-3,5-dimethoxybenzoic acid (7) and (1R,5S,7S)-7-[2-(4-hydroxyphenyl)ethyl]-2,6-dioxabicyclo[3.3.1]nonan-3-one (8). The structures of the new compounds were elucidated by detailed analyses of their MS, IR, 1D and 2D NMR spectral data and chemical evidence. Some of these compounds were evaluated in vitro for their antimicrobial activities against a wide range of microorganisms, but none of them exhibited noticeable activity.
Aging of Cast 35Cr-45Ni Heat Resistant Alloys With Different Carbon Content
Authors: Sustaita-Torres I. A. , Haro-Rodríguez S. , Colás R.
Published: September 2016

The changes in microstructure that took place in two heat-resistant after aging alloys at 750°C for a period of time of up to 1000 h are reported in this work. The alloys selected had a similar composition, with the exception in carbon content that was of 0.15 and 0.50 %. The material was obtained from centrifugal cast pipes and their microstructure was made of an austenitic dendrite matrix with interdendritic primary cabides; light optical and scanning electron microscopy analyses were conducted to identify these carbides as NbC and Cr7C3. Selected area analyses were conducted to quantify the primary carbides in the as-cast and aged conditions; these analyses revealed that their amount was unaffected by aging, but depended on the carbon content, with the predominance of NbC in the alloy with lower carbon content, due to the higher affinity of carbon to niobium. Aging affected the NbC particles, as they transformed into silicides, precipitation of secondary Cr23C6 particles took place, while Cr7C3 remained unaffected. The changes in microstructure that were observed by microscopy were confirmed by X-ray diffraction. The mechanical properties of the materials changed, as hardness and tensile strength increased, while the ductility in both alloys was reduced.
X-Ray and Neutron Diffraction Studies of Quenched and Partitioned (Q&P) Multiphase Steel Microstructures
Authors: Edmonds David , Bigg Timothy
Published: September 2016

Novel advanced steel developments in recent years have resulted in many steels with complex multiphase microstructures. Foremost currently are steels that contain significant fractions of untransformed parent austenite phase. “Quenched and partitioned” steels, commonly referred to as Q&P steels, important as potential advanced high-strength (AHS) automotive steels, are an example in which the austenite is chemically stabilized by carbon partitioning from martensite following an interrupted quench above the martensite finish temperature, Mf. It is evident that the progress of microstructural change during this novel quenching and partitioning treatment, the volume of untransformed austenite stabilized during partitioning and the behavior of this austenite according to its carbon content should be understood. In relation to these requirements, recent analysis of X-ray powder diffraction (XRD) and neutron diffraction experiments will be considered. Initially, the effect of sample preparation between the two measurement techniques is considered, followed by observation of the partitioning process in real time allowed by specially prepared Mn-containing experimental alloys, with and without a crucial silicon addition required to enable austenite retention during Q&P treatment.
Slow Cholinergic Modulation of Spike Probability in Ultra-Fast Time-Coding Sensory Neurons
Authors: Goyer David , Kurth Stefanie , Gillet Charlène , Keine Christian , Rübsamen Rudolf , Kuenzel Thomas
Published: September 2016

Sensory processing in the lower auditory pathway is generally considered to be rigid and thus less subject to modulation than central processing. However, in addition to the powerful bottom-up excitation by auditory nerve fibers, the ventral cochlear nucleus also receives efferent cholinergic innervation from both auditory and nonauditory top–down sources. We thus tested the influence of cholinergic modulation on highly precise time-coding neurons in the cochlear nucleus of the Mongolian gerbil. By combining electrophysiological recordings with pharmacological applicationin vitroandin vivo, we found 55–72% of spherical bushy cells (SBCs) to be depolarized by carbachol on two time scales, ranging from hundreds of milliseconds to minutes. These effects were mediated by nicotinic and muscarinic acetylcholine receptors, respectively. Pharmacological block of muscarinic receptors hyperpolarized the resting membrane potential, suggesting a novel mechanism of setting the resting membrane potential for SBC. The cholinergic depolarization led to an increase of spike probability in SBCs without compromising the temporal precision of the SBC outputin vitro.In vivo, iontophoretic application of carbachol resulted in an increase in spontaneous SBC activity. The inclusion of cholinergic modulation in an SBC model predicted an expansion of the dynamic range of sound responses and increased temporal acuity. Our results thus suggest of a top–down modulatory system mediated by acetylcholine which influences temporally precise information processing in the lower auditory pathway.
The Role of Striatal Feedforward Inhibition in the Maintenance of Absence Seizures
Authors: Arakaki Takafumi , Mahon Séverine , Charpier Stéphane , Leblois Arthur , Hansel David
Published: September 2016

Absence seizures are characterized by brief interruptions of conscious experience accompanied by oscillations of activity synchronized across many brain areas. Although the dynamics of the thalamocortical circuits are traditionally thought to underlie absence seizures, converging experimental evidence supports the key involvement of the basal ganglia (BG). In this theoretical work, we argue that the BG are essential for the maintenance of absence seizures. To this end, we combine analytical calculations with numerical simulations to investigate a computational model of the BG-thalamo-cortical network. We demonstrate that abnormally strong striatal feedforward inhibition can promote synchronous oscillatory activity that persists in the network over several tens of seconds as observed during seizures. We show that these maintained oscillations result from an interplay between the negative feedback through the cortico-subthalamo-nigral pathway and the striatal feedforward inhibition. The negative feedback promotes epileptic oscillations whereas the striatal feedforward inhibition suppresses the positive feedback provided by the cortico-striato-nigral pathway. Our theory is consistent with experimental evidence regarding the influence of BG on seizures (e.g., with the fact that a pharmacological blockade of the subthalamo-nigral pathway suppresses seizures). It also accounts for the observed strong suppression of the striatal output during seizures. Our theory predicts that well-timed transient excitatory inputs to the cortex advance the termination of absence seizures. In contrast with the thalamocortical theory, it also predicts that reducing the synaptic transmission along the cortico-subthalamo-nigral pathway while keeping constant the average firing rate of substantia nigra pars reticulata reduces the incidence of seizures.

SIGNIFICANCE STATEMENTAbsence seizures are characterized by brief interruptions of consciousness accompanied by abnormal brain oscillations persisting tens of seconds. Thalamocortical circuits are traditionally thought to underlie absence seizures. However, recent experiments have highlighted the key role of the basal ganglia (BG). This work argues for a novel theory according to which the BG drive the oscillatory patterns of activity occurring during the seizures. It demonstrates that abnormally strong striatal feedforward inhibition promotes synchronous oscillatory activity in the BG-thalamo-cortical network and relate this property to the observed strong suppression of the striatal output during seizures. The theory is compatible with virtually all known experimental results, and it predicts that well-timed transient excitatory inputs to the cortex advance the termination of absence seizures.
Youthful Brains in Older Adults: Preserved Neuroanatomy in the Default Mode and Salience Networks Contributes to Youthful Memory in Superaging
Authors: Sun Felicia W. , Stepanovic Michael R. , Andreano Joseph , Barrett Lisa Feldman , Touroutoglou Alexandra , Dickerson Bradford C.
Published: September 2016

Decline in cognitive skills, especially in memory, is often viewed as part of “normal” aging. Yet some individuals “age better” than others. Building on prior research showing that cortical thickness in one brain region, the anterior midcingulate cortex, is preserved in older adults with memory performance abilities equal to or better than those of people 20–30 years younger (i.e., “superagers”), we examined the structural integrity of two large-scale intrinsic brain networks in superaging: the default mode network, typically engaged during memory encoding and retrieval tasks, and the salience network, typically engaged during attention, motivation, and executive function tasks. We predicted that superagers would have preserved cortical thickness in critical nodes in these networks. We defined superagers (60–80 years old) based on their performance compared to young adults (18–32 years old) on the California Verbal Learning Test Long Delay Free Recall test. We found regions within the networks of interest where the cerebral cortex of superagers was thicker than that of typical older adults, and where superagers were anatomically indistinguishable from young adults; hippocampal volume was also preserved in superagers. Within the full group of older adults, thickness of a number of regions, including the anterior temporal cortex, rostral medial prefrontal cortex, and anterior midcingulate cortex, correlated with memory performance, as did the volume of the hippocampus. These results indicate older adults with youthful memory abilities have youthful brain regions in key paralimbic and limbic nodes of the default mode and salience networks that support attentional, executive, and mnemonic processes subserving memory function.

SIGNIFICANCE STATEMENTMemory performance typically declines with age, as does cortical structural integrity, yet some older adults maintain youthful memory. We tested the hypothesis that superagers (older individuals with youthful memory performance) would exhibit preserved neuroanatomy in key brain networks subserving memory. We found that superagers not only perform similarly to young adults on memory testing, they also do not show the typical patterns of brain atrophy in certain regions. These regions are contained largely within two major intrinsic brain networks: the default mode network, implicated in memory encoding, storage, and retrieval, and the salience network, associated with attention and executive processes involved in encoding and retrieval. Preserved neuroanatomical integrity in these networks is associated with better memory performance among older adults.
DrosophilaNeprilysins Are Involved in Middle-Term and Long-Term Memory
Authors: Turrel Oriane , Lampin-Saint-Amaux Aurélie , Préat Thomas , Goguel Valérie
Published: September 2016

Neprilysins are type II metalloproteinases known to degrade and inactivate a number of small peptides. Neprilysins in particular are the major amyloid-β peptide-degrading enzymes. In mouse models of Alzheimer's disease, neprilysin overexpression improves learning and memory deficits, whereas neprilysin deficiency aggravates the behavioral phenotypes. However, whether these enzymes are involved in memory in nonpathological conditions is an open question.Drosophila melanogasteris a well suited model system with which to address this issue. Several memory phases have been characterized in this organism and the neuronal circuits involved are well described. The fly genome contains five neprilysin-encoding genes, four of which are expressed in the adult. Using conditional RNA interference, we show here that all four neprilysins are involved in middle-term and long-term memory. Strikingly, all four are required in a single pair of neurons, the dorsal paired medial (DPM) neurons that broadly innervate the mushroom bodies (MBs), the center of olfactory memory. Neprilysins are also required in the MB, reflecting the functional relationship between the DPM neurons and the MB, a circuit believed to stabilize memories. Together, our data establish a role for neprilysins in two specific memory phases and further show that DPM neurons play a critical role in the proper targeting of neuropeptides involved in these processes.

SIGNIFICANCE STATEMENTNeprilysins are endopeptidases known to degrade a number of small peptides. Neprilysin research has essentially focused on their role in Alzheimer's disease and heart failure. Here, we useDrosophila melanogasterto study whether neprilysins are involved in memory.Drosophilacan form several types of olfactory memory and the neuronal structures involved are well described. Four neprilysin genes are expressed in adultDrosophila. Using conditional RNA interference, we show that all four are specifically involved in middle-term memory (MTM) and long-term memory (LTM) and that their expression is required in the mushroom bodies and also in a single pair of closely connected neurons. The data show that these two neurons play a critical role in targeting neuropeptides essential for MTM and LTM.
Contributions of Rod and Cone Pathways to Retinal Direction Selectivity Through Development
Authors: Rosa Juliana M. , Morrie Ryan D. , Baertsch Hans C. , Feller Marla B.
Published: September 2016

Direction selectivity is a robust computation across a broad stimulus space that is mediated by activity of both rod and cone photoreceptors through the ON and OFF pathways. However, rods, S-cones, and M-cones activate the ON and OFF circuits via distinct pathways and the relative contribution of each to direction selectivity is unknown. Using a variety of stimulation paradigms, pharmacological agents, and knockout mice that lack rod transduction, we found that inputs from the ON pathway were critical for strong direction-selective (DS) tuning in the OFF pathway. For UV light stimulation, the ON pathway inputs to the OFF pathway originated with rod signaling, whereas for visible stimulation, the ON pathway inputs to the OFF pathway originated with both rod and M-cone signaling. Whole-cell voltage-clamp recordings revealed that blocking the ON pathway reduced directional tuning in the OFF pathway via a reduction in null-side inhibition, which is provided by OFF starburst amacrine cells (SACs). Consistent with this, our recordings from OFF SACs confirmed that signals originating in the ON pathway contribute to their excitation. Finally, we observed that, for UV stimulation, ON contributions to OFF DS tuning matured earlier than direct signaling via the OFF pathway. These data indicate that the retina uses multiple strategies for computing DS responses across different colors and stages of development.

SIGNIFICANCE STATEMENTThe retina uses parallel pathways to encode different features of the visual scene. In some cases, these distinct pathways converge on circuits that mediate a distinct computation. For example, rod and cone pathways enable direction-selective (DS) ganglion cells to encode motion over a wide range of light intensities. Here, we show that although direction selectivity is robust across light intensities, motion discrimination for OFF signals is dependent upon ON signaling. At eye opening, ON directional tuning is mature, whereas OFF DS tuning is significantly reduced due to a delayed maturation of S-cone to OFF cone bipolar signaling. These results provide evidence that the retina uses multiple strategies for computing DS responses across different stimulus conditions.
FBW7 suppression leads to SOX9 stabilization and increased malignancy in medulloblastoma
Authors: Suryo Rahmanto Aldwin , Savov Vasil , Brunner Andrä , Bolin Sara , Weishaupt Holger , Malyukova Alena , Rosén Gabriela , Čančer Matko , Hutter Sonja , Sundström Anders , Kawauchi Daisuke , Jones David TW , Spruck Charles , Taylor Michael D , Cho Yoon‐Jae , Pfister Stefan M , Kool Marcel , Korshunov Andrey , Swartling Fredrik J , Sangfelt Olle
Published: September 2016

SOX9 is a master transcription factor that regulates development and stem cell programs. However, its potential oncogenic activity and regulatory mechanisms that control SOX9 protein stability are poorly understood. Here, we show that SOX9 is a substrate of FBW7, a tumor suppressor, and a SCF (SKP1/CUL1/F‐box)‐type ubiquitin ligase. FBW7 recognizes a conserved degron surrounding threonine 236 (T236) in SOX9 that is phosphorylated by GSK3 kinase and consequently degraded by SCFFBW7α. Failure to degrade SOX9 promotes migration, metastasis, and treatment resistance in medulloblastoma, one of the most common childhood brain tumors. FBW7 is either mutated or downregulated in medulloblastoma, and in cases where FBW7 mRNA levels are low, SOX9 protein is significantly elevated and this phenotype is associated with metastasis at diagnosis and poor patient outcome. Transcriptional profiling of medulloblastoma cells expressing a degradation‐resistant SOX9 mutant reveals activation of pro‐metastatic genes and genes linked to cisplatin resistance. Finally, we show that pharmacological inhibition of PI3K/AKT/mTOR pathway activity destabilizes SOX9 in a GSK3/FBW7‐dependent manner, rendering medulloblastoma cells sensitive to cytostatic treatment.
Activin A upregulates PTGS2 expression and increases PGE2 production in human granulosa-lutein cells
Authors: Liu Pang-Pin , Chang Hsun-Ming , Cheng Jung-Chien , Leung Peter C K
Published: September 2016

Activin A is one of the members of transforming growth factor-β superfamily that is expressed in human large luteal cells, and may act in an autocrine/paracrine manner to regulate luteal function. Prostaglandin-endoperoxide synthase 2 (PTGS2) enzyme and its derivative, prostaglandin E2 (PGE2), play significant roles in the regulation of corpus luteum formation and maintenance. To date, whether activin A can induce the expression of PTGS2 and the production of PGE2 in human granulosa-lutein cells is largely unknown. The aim of this study was to examine the effects of activin A on the regulation of PTGS2 expression and PGE2 production in human granulosa-lutein cells, and to investigate the underlying signal transduction mechanisms. In this study, the immortalized (SVOG cells) and primary human granulosa-lutein cells were used as the cell models. A TGF-β/activin type I receptor inhibitor, SB431542 and small interfering RNAs were used to investigate the activin A-induced downstream signaling pathway. We have demonstrated that activin A upregulated the expression of PTGS2 and increased the production of PGE2 via an ACVR1B-mediated SMAD2/3–SMAD4 signaling pathway. Our results suggest that activin A may be involved in the modulation of human corpus luteum formation via the induction of PTGS2 expression and PGE2 production.
The FAME Trials: Impact on Clinical Decision Making
Authors: Heyndrickx Guy R ,   Cardiovascular Center Aalst, OLV-Clinic, Aalst, Belgium, Tóth Gábor G ,   University Heart Center, Medical University of Graz, Graz, Austria
Published: September 2016

Careful and stepwise evaluation of the fractional flow reserve (FFR) index has been performed over the years, culminating in the landmark Fractional Flow Reserve Versus Angiography for Multivessel Evaluation (FAME) and Fractional Flow Reserve-Guided Percutaneous Coronary Intervention Plus Optimal Medical Treatment Versus Optimal Medical Treatment Alone in Patients with Stable Coronary Artery Disease (FAME II) trials. Findings from these studies demonstrated unequivocally the overall inadequacy of angiography versus FFR to correctly assess stenosis severity. Thus, proof of concept and clinical applicability was established beyond debate and will be discussed here.
Marsupials and rodents (Didelphimorphia and Rodentia) of upper Rio Acre, with new data on Oxymycterus inca Thomas, 1900 from Brazil
Authors: Abreu-Júnior Edson F. , De Freitas Marco A. , Lapenta Marina J. , Venâncio Nathocley M. , De França Daniella P. F. , Percequillo Alexandre R.
Published: September 2016

Our goal was to inventory marsupial and rodent species from two conservation units (Reserva Extrativista Chico Mendes and Estação Ecológica do Rio Acre) of the upper Rio Acre, in Brazilian Amazonia, as well as to provide new data on the morphology and geographic distribution for several species. We recorded 25 species, including seven marsupials and 18 rodents. Among these, there are poorly sampled species in Brazil, such as Marmosa regina and Dactylomys boliviensis. We document range extensions (about 450 km towards southeastern Acre state) of Neacomys musseri, Dasyprocta fuliginosa, and Proechimys cuvieri. We also present the first confirmed record of an undescribed species of Monodelphis in Acre state and the second collecting record of Oxymycterus inca in Brazil. We describe the morphology and morphometrics of upper Rio Acre specimens of O. inca. Finally, we compare our results with other inventories in the Amazon region and discuss the high efficiency of pitfall traps for capturing nonvolant small mammals.
Recent benthic foraminifera from the Itaipu Lagoon, Rio de Janeiro (southeastern Brazil)
Authors: Raposo Débora , Laut Vanessa , Clemente Iara , Martins Virginia , Frontalini Fabrizio , Silva Frederico , Lorini Maria Lúcia , Fortes Rafael , Laut Lazaro
Published: September 2016

Itaipu Lagoon is located near the mouth of Guanabara Bay and has great importance for recreation to the city of Niterói, Rio de Janeiro state, Brazil. Several studies have documented foraminiferan diversity at Guanabara Bay, but none in Itaipu Lagoon. Therefore, this study lists and provides images of foraminiferal species collected from Itaipu Lagoon. A total of 35 species belonging to 23 genera were collected, grouped in 17 families and four orders. Ammonia tepida was the species with the highest occurrence. This study represents a baseline work for future investigations.
WATER REQUIREMENT ESTIMATE FOR THE REPRODUCTIVE PERIOD OF MANGO ORCHADS IN THE NORTHEAST OF THE STATE OF PARÁ, BRAZIL
Authors: SOUZA PAULO JORGE DE OLIVEIRA PONTE DE , RODRIGUES JULIANA CHAGAS , SOUSA ADRIANO MARLISOM LEÃO DE , LIMA RENATA TRINDADE DE , ROCHA EDSON JOSÉ PAULINO DA , ORTEGA-FARIAS SAMUEL
Published: September 2016

ABSTRACT The aim of this study was to estimate the water consumption in mango orchard during its phenological stages in the northeastern of the State of Pará, Brazil. For this purpose, it was installed and instrumented a micrometeorological tower in a mango orchard, cv. Tommy Atkins, of 22 years old, with data collected during the crops of 2010/2011 and of 2011/2012. The actual crop evapotranspiration was estimated from the energy balance using the Bowen ratio technique. The crops were subjected to different weather conditions, consequently, some differences in the Bowen ration values were observed. The evapotranspiration suffered influences of meteorological conditions during the period. The actual crop evapotranspiration during its reproductive period ranged between 402.9 and 420 mm with a mean daily water consumption of 3.8 mm at flowering, of 4.25 mm at fruit fall, of 3.56 mm at fruit formation, of 3.0 mm at fruit maturation and of 3.73 mm for the whole period.
PLOT SIZE IN THE EVALUATION OF PAPAYA SEEDLINGS 'BAIXINHO DE SANTA AMÁLIA' IN TUBES
Authors: CELANTI HUMBERTO FELIPE , SCHMILDT OMAR , ALEXANDRE RODRIGO SOBREIRA , CATTANEO LAERCIO FRANCISCO , SCHMILDT EDILSON ROMAIS
Published: September 2016

ABSTRACT Were evaluated three characters in papaya seedlings 'Baixinho de Santa Amália' to estimate the optimum plot size and the number of replications in a completely randomized experiment, a randomized block and Latin square. The characters were seedling height, leaf number and length of roots from uniformity test with 240 seedlings. The determination of the optimum plot size was done by applying the method of Hatheway (1961). The number of seedlings per plot for seedling production is variable depending on the number of treatments and replications assumed precision, the character in question and the experimental design. Comparing designs, the plot size is greater in the Latin square, followed by a randomized block design and completely randomized, and this difference is more pronounced the lower the number of treatments and replicates used. For the same number of treatments and the same precision, the most efficient use of the experimental area is given using smaller plot, with more replications, which require less space in the nursery than larger plots with fewer replications. For experiments completely randomized and randomized blocks with five or more treatments, four replications, and precision of 15% around the mean, it is recommended to use nine seedlings per plot.
Caracterização da agressividade e atividade enzimática de isolados de Colletotrichum spp. associados à antracnose do abacate
Authors: Tozze Júnior Hugo José , Firmino Ana Carolina , Fischer Ivan Herman , Furtado Edson Luiz , Massola Júnior Nelson Sidnei
Published: September 2016

RESUMO A antracnose é a principal doença pós-colheita do abacate. O presente trabalho teve como objetivos caracterizar a agressividade e a atividade enzimática de 30 isolados de Colletotrichum spp. de abacate. Abacates ‘Fuerte’ foram inoculados com disco de BDA contendo estruturas de cada isolado e após sete dias mensuraram-se os diâmetros das lesões. Dois grupos de isolados foram distinguidos quanto à agressividade pelo teste de teste de Scott-Knott (p=0,05), um com lesões entre 34,0 e 38,2 mm e outro com lesões entre 38,7 e 44,0 mm de diâmetro. Para caracterização enzimática, avaliaram-se as áreas dos halos formados em substratos específicos para detecção de amilase, celulase, lacase, lipase, pectato liase e protease e a atividade da enzima catalase. Os isolados não produziram amilase suficiente para formação de halo em meio de cultura. Todos os isolados produziram catalase, pectato liase e protease, enquanto 46% produziram lacase e 97% tiveram as atividades da celulase e lipase detectadas. Distinguiram-se dois grupos de isolados para as enzimas catalase e pectato liase, cinco grupos para a celulase, seis grupos para a lacase e sete grupos para as enzimas lipase e protease, pelo teste de teste de Scott-Knott (p=0,05). Não houve relação entre as atividades enzimáticas e a agressividade dos isolados.