bluuebunny/crossref_metadata_2025 huggingface dataset:
Charge transport and memristive properties of graphene quantum dots embedded in poly(3-hexylthiophene) matrix
Authors: Cosmin Obreja Alexandru , Cristea Dana , Mihalache Iuliana , Radoi Antonio , Gavrila Raluca , Comanescu Florin , Kusko Cristian
Published: August 2014

We show that graphene quantum dots (GQD) embedded in a semiconducting poly(3-hexylthiophene) polymeric matrix act as charge trapping nanomaterials. In plane current-voltage (I-V) measurements of thin films realized from this nanocomposite deposited on gold interdigitated electrodes revealed that the GQD enhanced dramatically the hole transport. I-V characteristics exhibited a strong nonlinear behavior and a pinched hysteresis loop, a signature of a memristive response. The transport properties of this nanocomposite were explained in terms of a trap controlled space charge limited current mechanism.
Interface composition between Fe3O4 nanoparticles and GaAs for spintronic applications
Authors: Hihath Sahar , Kiehl Richard A. , Benthem Klaus van
Published: August 2014

Recent interest in spintronic applications has necessitated the study of magnetic materials in contact with semiconductor substrates; importantly, the structure and composition of these interfaces can influence both device functionality and the magnetic properties. Nanoscale ferromagnet/semiconductor structures are of particular interest. In this study, the interface structure between a monolayer of ferromagnetic magnetite (Fe3O4) nanoparticles and a GaAs substrate was studied using cross-sectional transmission electron microscopy techniques. It was found that a continuous amorphous oxide interface layer separates the nanoparticles from the GaAs substrate, and that iron diffused into the interface layer forming a compositional gradient. Electron energy-loss near-edge fine structures of the O K absorption edge revealed that the amorphous oxide is composed of γ-Fe2O3 directly underneath the Fe3O4 nanoparticles, followed by a solid solution of Ga2O3 and FeO and mostly Ga2O3 when approaching the buckled oxide/substrate interface. Real-space density functional theory calculations of the dynamical form factor confirmed the experimental observations. The implication of the findings on the optimization of these structures for spin injection is discussed.
Study on effect of electrode force on resistance spot welding process
Authors: Zhou Kang , Cai Lilong
Published: August 2014

This paper deals with the effect of electrode force on resistance spot welding process. As one of the most important parameters during the process, the electrode force can influence the process in different aspects. Dynamic resistance, which can reflect the internal physical variation of the workpiece, is employed to monitor the characteristic variation of the workpieces. According to theoretical analysis, large electrode force may easily induce surface expulsion. Also, it can decrease the overall dynamic resistance values and postpone the time when first melting point appears, as well as enlarge the duration between times when first melting point and peak value appear. Larger electrode force induces the initial smaller nugget diameter, and then the nugget diameter has a higher growth speed. However, the overall nugget diameter may be smaller and its growth terminates earlier than when smaller electrode force is applied. Final experiments validated all the theoretical analysis.
Yield and leakage currents of large area lattice matched InP/InGaAs heterostructures
Authors: Olsson Anders , Aierken Abuduwayiti , Jussila Henri , Bauer Jan , Oksanen Jani , Breitenstein Otwin , Lipsanen Harri , Tulkki Jukka
Published: August 2014

Demonstrating and harnessing electroluminescent cooling at technologically viable cooling powers requires the ability to routinely fabricate large area high quality light-emitting diodes (LEDs). Detailed information on the performance and yield of relevant large area devices is not available, however. Here, we report extensive information on the yield and related large area scaling of InP/InGaAs LEDs and discuss the origin of the failure mechanisms based on lock-in thermographic imaging. The studied LEDs were fabricated as mesa structures of various sizes on epistructures grown at five different facilities specialized in the growth of III-V compound semiconductors. While the smaller mesas generally showed relatively good electrical characteristics and low leakage current densities, some of them also exhibited unusually large leakage current densities. The provided information is critical for the development and design of the optical cooling technologies relying on large area devices.
Graphene-based terahertz tunable plasmonic directional coupler
Authors: He Meng-Dong , Wang Kai-Jun , Wang Lei , Li Jian-Bo , Liu Jian-Qiang , Huang Zhen-Rong , Wang Lingling , Wang Lin , Hu Wei-Da , Chen Xiaoshuang
Published: August 2014

We propose and numerically analyze a terahertz tunable plasmonic directional coupler which is composed of a thin metal film with a nanoscale slit, dielectric grating, a graphene sheet, and a dielectric substrate. The slit is employed to generate surface plasmon polaritons (SPPs), and the metal-dielectric grating-graphene-dielectric constructs a Bragg reflector, whose bandgap can be tuned over a wide frequency range by a small change in the Fermi energy level of graphene. As a graphene-based Bragg reflector is formed on one side of the slit, the structure enables SPP waves to be unidirectionally excited on the other side of the slit due to SPP interference, and the SPP waves in the Bragg reflector can be efficiently switched on and off by tuning the graphene's Fermi energy level. By introducing two optimized graphene-based Bragg reflectors into opposite sides of the slit, SPP waves can be guided to different Bragg reflectors at different Fermi energy levels, thus achieving a tunable bidirectional coupler.
Towards reproducible, scalable lateral molecular electronic devices
Authors: Durkan Colm , Zhang Qian
Published: August 2014

An approach to reproducibly fabricate molecular electronic devices is presented. Lateral nanometer-scale gaps with high yield are formed in Au/Pd nanowires by a combination of electromigration and Joule-heating-induced thermomechanical stress. The resulting nanogap devices are used to measure the electrical properties of small numbers of two different molecular species with different end-groups, namely 1,4-butane dithiol and 1,5-diamino-2-methylpentane. Fluctuations in the current reveal that in the case of the dithiol molecule devices, individual molecules conduct intermittently, with the fluctuations becoming more pronounced at larger biases.
Surface plasmon resonance assisted rapid laser joining of glass
Authors: Zolotovskaya Svetlana A. , Tang Guang , Wang Zengbo , Abdolvand Amin
Published: August 2014

Rapid and strong joining of clear glass to glass containing randomly distributed embedded spherical silver nanoparticles upon nanosecond pulsed laser irradiation (∼40 ns and repetition rate of 100 kHz) at 532 nm is demonstrated. The embedded silver nanoparticles were ∼30–40 nm in diameter, contained in a thin surface layer of ∼10 μm. A joint strength of 12.5 MPa was achieved for a laser fluence of only ∼0.13 J/cm2 and scanning speed of 10 mm/s. The bonding mechanism is discussed in terms of absorption of the laser energy by nanoparticles and the transfer of the accumulated localised heat to the surrounding glass leading to the local melting and formation of a strong bond. The presented technique is scalable and overcomes a number of serious challenges for a widespread adoption of laser-assisted rapid joining of glass substrates, enabling applications in the manufacture of microelectronic devices, sensors, micro-fluidic, and medical devices.
Understanding peculiarities in the optoelectronic characteristics of light emitting diodes based on (In,Ga)N/GaN nanowires
Authors: Musolino M. , Tahraoui A. , Limbach F. , Lähnemann J. , Jahn U. , Brandt O. , Geelhaar L. , Riechert H.
Published: August 2014

We investigate the effect of the p-type top contact on the optoelectronic characteristics of light emitting diodes (LEDs) based on (In,Ga)N/GaN nanowire (NW) ensembles grown by molecular beam epitaxy on Si substrates. We compare devices fabricated with either Ni/Au or indium tin oxide (ITO) top contact. The NW-LEDs with ITO exhibit a number density of NWs emitting electroluminescence about ten times higher, significantly lower turn-on voltage and series resistance, and a relative external quantum efficiency more than one order of magnitude higher than the sample with Ni/Au. These results show that limitations in the performance of such devices reported so far can be overcome by improving the p-type top-contact.
Viral nanoparticle-encapsidated enzyme and restructured DNA for cell delivery and gene expression
Authors: Liu Jinny L. , Dixit Aparna Banerjee , Robertson Kelly L. , Qiao Eric , Black Lindsay W.
Published: August 2014

Significance

The importance of viral icosahedral capsid-based nanoparticles (NPs) as cell-delivery vehicles is now being recognized. Virtually any specific protein and nucleic acid can be encapsidated together into a phage T4 capsid that can display surface-binding ligands for tissue targeting. In this study, T4 NPs packed in vivo with active cyclic recombination (Cre) recombinase and in vitro with fluorescent mCherry expression plasmid DNA were delivered into cancer cells. When released into cells together, the packaged active Cre recombinase within the capsid circularizes the packaged DNA of the linear expression plasmid, enhancing the expression of the mCherry gene. The efficient and specific packaging and unpackaging of DNA and active protein together into targeted cells has potential applications in targeted gene therapy and cancer therapy.
Staphylococcus aureus
secretes a unique class of neutrophil serine protease inhibitors
Authors: Stapels Daphne A. C. , Ramyar Kasra X. , Bischoff Markus , von Köckritz-Blickwede Maren , Milder Fin J. , Ruyken Maartje , Eisenbeis Janina , McWhorter William J. , Herrmann Mathias , van Kessel Kok P. M. , Geisbrecht Brian V. , Rooijakkers Suzan H. M.
Published: August 2014

Significance

Neutrophils are among the first immune cells to migrate to the site of infection and clear invading bacteria. They store large amounts of neutrophil serine proteases (NSPs) that play key roles in immune defense. Unfortunately, NSPs also contribute to tissue destruction in a variety of inflammatory disorders. In this study we discover that the pathogenic bacterium
Staphylococcus aureus
secretes a family of highly potent and specific NSP inhibitors that promote the pathogenicity of this bacterium in vivo. From crystallography experiments, we conclude that these proteins constitute a unique class of NSP inhibitors, which can be used to design novel treatment strategies against excessive NSP activity. Furthermore, this study significantly increases our understanding of the complex nature of
S. aureus
infections.
Nutritional strategies to support concurrent training
Authors: Perez‐Schindler Joaquin , Hamilton D. Lee , Moore Daniel R. , Baar Keith , Philp Andrew
Published: August 2014

Concurrent training (the combination of endurance exercise to resistance training) is a common practice for athletes looking to maximise strength and endurance. Over 20 years ago, it was first observed that performing endurance exercise after resistance exercise could have detrimental effects on strength gains. At the cellular level, specific protein candidates have been suggested to mediate this training interference; however, at present, the physiological reason(s) behind the concurrent training effect remain largely unknown. Even less is known regarding the optimal nutritional strategies to support concurrent training and whether unique nutritional approaches are needed to support endurance and resistance exercise during concurrent training approaches. In this review, we will discuss the importance of protein supplementation for both endurance and resistance training adaptation and highlight additional nutritional strategies that may support concurrent training. Finally, we will attempt to synergise current understanding of the interaction between physiological responses and nutritional approaches into practical recommendations for concurrent training.
Reasoning, Biases and Dual Processes: The Lasting Impact of Wason (1960)
Authors: Evans Jonathan St B. T.
Published: August 2014

Wason (1960) published a relatively short experimental paper, in which he introduced the 2-4-6 problem as a test of inductive reasoning. This paper became one of the most highly cited to be published in the Quarterly Journal of Experimental Psychology and is significant for a number of reasons. First, the 2-4-6 task itself was ingenious and yielded evidence of error and bias in the intelligent participants who attempted it. Research on the 2-4-6 problem continues to the present day. More importantly, it was Wason's first paper on reasoning and one which made strong claims for bias and irrationality in a period dominated by rationalist writers like Piaget. It set in motion the study of cognitive biases in thinking and reasoning, well before the start of Tversky and Kahneman's famous heuristics and biases research programme. I also show here something for which Wason has received insufficient credit. It was Wason's work on this task and his later studies of his four card selection task that led to the first development of the dual process theory of reasoning which is so dominant in the current literature on the topic more than half a century later.
Tracking Arabinoxylans Through the Preparation of Pancakes
Authors: Kiszonas Alecia M. , Fuerst E. Patrick , Luthria Devanand , Morris Craig F.
Published: August 2014

Arabinoxylans (AX) are well known to have a wide‐ranging influence on wheat (Triticum aestivum L.) end‐use quality and are associated with health benefits. There is little information on the effects of processing on AX properties in high‐water‐content batter‐based products and on the associations between AX properties and end‐use quality in such products. The objective of this study was to track total and water‐extractable AX (TAX and WEAX, respectively) contents and determine changes in AX characteristics throughout the baking process of pancakes, a batter‐based wheat product. The TAX and WEAX contents along with the arabinose‐to‐xylose (A/X) ratio were quantified in refined flour and wholemeal as well as batter and pancakes from two soft and three hard wheat varieties. ANOVA F values indicated that the variation in TAX content was influenced most by sample type differences (flour versus batter versus pancakes), whereas varietal differences were responsible for the greatest differences in WEAX. In separate analyses on refined and wholemeal flours, the highest F values were for variety WEAX, largely attributed to the higher WEAX content of the three hard varieties. WEAX levels generally increased slightly from flour to batter to pancakes in refined flour. The WEAX content in flour, batter, and pancakes of both refined flour and wholemeal was highly correlated with pancake volume. These observations suggest moderate changes in wheat AX characteristics during processing and a positive association of WEAX levels with end‐product volume in a batter‐based product.
Effects of Temperature, Wetness Duration, and Moisture on the Conidial Germination, Infection, and Disease Incubation Period of Glomerella cingulata
Authors: Wang Bing , Li Bao-Hua , Dong Xiang-Li , Wang Cai-Xia , Zhang Zhen-Fang
Published: August 2014

Glomerella leaf spot (GLS) caused by Glomerella cingulata is a newly emergent disease that results in severe defoliation and fruit spots. Currently, GLS is not effectively controlled in China due to a lack of understanding of its epidemiology. Therefore, the effects of temperature, wetness duration, and moisture on conidial germination, infection, and the disease incubation period of GLS were examined by inoculating cv. Gala apple leaves with a conidial suspension and performing in vitro germination assays. Conidia could germinate and form appressoria at temperatures ranging from 5 to 35°C, with an optimum temperature of 27.6°C. The germination of conidia required free water or a nearly saturated relative humidity, with only a few conidia germinating and forming appressoria when the RH was less than 99%. The conidial germination dynamics at 10, 25, and 30°C were well represented by three logistic models. The infection of cv. Gala apple leaves by conidia occurred at temperatures ranging from 15 to 35°C. The minimum wetness duration required for infection by conidia at different temperatures was described using a polynomial equation, and the lowest minimum wetness duration was 2.76 h, which occurred at 27.6°C according to the polynomial. Successful infection by conidia was represented by the number of lesions per leaf, which increased with extended wetness durations at the conidial infection stage for six tested temperatures, with the exception of 10°C, when the minimum wetness durations were satisfied. The associations of successfully infected conidia with wetness duration at temperatures of 15, 20, 25, and 30°C were described by four logistic models. Conidia infections developed into visible lesions at temperatures ranging from 15 to 30°C, and the shortest incubation period of 2 days was observed at 25°C. These data and models can be used to construct forecasting models and develop effective control systems for Glomerella leaf spot.
First Report of Cucumber mosaic virus in Agastache rugosa in China
Authors: Du J. , Zhang C. M. , Niu Y. B.
Published: August 2014

Agastache rugosa (family Lamiaceae) is one of the most common herbs of traditional Chinese medicine in China, and the species increasingly gains popularity on the international market. In June 2012, typical mosaic symptoms were observed on many A. rugosa plants in a field in Shanxi Province. The incidence of this disease reached more than 60% in a 2.6-ha field. Seven symptomatic plants were tested by DAS-ELISA using monoclonal antibodies specific for Tobacco mosaic virus (TMV), Cucumber mosaic virus (CMV), and Tomato mosaic virus (ToMV); all antisera used in DAS-ELISA were generated and validated in our laboratory. CMV was found in all seven samples tested, but not TMV and ToMV. Double-stranded RNAs (dsRNA) extracted from infected leaves were used as templates in the subsequent two-step RT-PCR reaction (1). In order to further confirm the presence of CMV, a pair of specific primers (forward: 5′-ACGTCGACCATGGACAAATC-3′, and reverse: 5′-TACCCGGGTCAGACTGGTAGCACC-3′) based on the coat protein gene sequence of CMV were used to amplify PCR products of the expected size (657 bp) from ELISA-positive samples (2). These PCR products were cloned into pUCm-T Vector (Sangon Biotech, Shanghai) and sequenced. Five independent clones have been sequenced to obtain the consensus sequence. This consensus sequence (GenBank Accession No. JQ403529) was compared with other CMV sequences available in GenBank using DNAMAN. The partial CMV coat protein sequence showed the highest 97.9% nucleotide identity with a subgroup IB CMV isolate from China (DQ459481). To our knowledge, this is the first report of the natural occurrence of CMV on A. rugosa.

References: (1) M. Krajacić et al. J. Chromatogr. A. 1144:111, 2007. (2) F. Li et al. J. Zhejiang Univ. 26:261, 2000.
Occurrence and Characterization of Bean common mosaic virus Strain NL1 in Iowa
Authors: Martin K. , Hill J. H. , Cannon S.
Published: August 2014

A legume survey in Story County was conducted to characterize legume viruses present in Iowa and potentially problematic to soybeans. Symptomatic (chlorosis, leaf curl, or vein banding) and non-symptomic leaves were selected from Apios americana, Cyamopsis tetragonolobus, Desmodium spp., Glycine max, Lablab purpureus, Lotus japonicus, Phaseolus coccineus, Phaseolus vulgaris, Vicia faba, Vigna ungulculata, and Chenopodium quinoa (an indicator species), and sent to Agdia Inc. for their Crop Screen: “Bean (Soybean)” tests. Cowpea mosaic virus (in L. purpureus), Southern bean mosaic virus (in A. americana), Soybean dwarf virus (in L. purpureus), and Tobacco streak virus (in Desmodium spp.) were identified. In addition, P. vulgaris was found positive in the serological Potyvirus group test, and was further characterized using reverse transcription (RT)-PCR using total RNA (Qiagen RNeasy extraction kit) from symptomatic leaves. A ~1-kb fragment of virus genome was amplified using degenerate primers, forward: 5′ TGYGTNGAYGAYYTYAAYAA 3′ (3) and reverse: 5′ TCRTARAARTCRAAIGCRTAICKIG 3′ (2). The closest GenBank BLAST hits for the sequence were BCMV strain NL1 (GenBank Accession No. AY112735) and BCMV MS1 (EU761198), both at 97% identity. RNA sequencing using an Illumina HiSeq 2500 (100 base paired ends) allowed construction of a nearly complete viral sequence from positions 38 to 10,037 nt (KM023744). This showed 99% similarity to BCMV-NL1 (AY112735) and 98% similarity to BCMV MS1 (EU761198). The BCMV isolate was recovered on the P. vulgaris cv. Taos Red and tested against a panel of Phaseolus, Glycine, and other hosts. Symptomatic hosts (vein-banding, mosaic, stunting, and leaf curl) were P. vulgaris cvs. Starlight, Tohono O'odham vaya Amarillo, Black Valentine Stringless, Sutter Pink, Hidatsa red, Stringless Green Refugee, Burpees Stringless Improved Bush, Princess d'Artois, Princess Double de Holland, and Dubelle Witte. Asymptomatic hosts included P. vulgaris cvs. Sierra, Great Northern Tara, Tara, and Vigna radiata. Non-host plants were P. vulgaris cvs. Michelite 62, Great Northern UI 31, Great Northern UI 123, Pure Gold Wax, Top Crop, Redlands Greanleaf B, Red Mexican UI 34, Imuna, Monroe, Pinto UI 114, Widusa, Othello, Sacramento, Red Kidney, Provider, Black Turtle Soup, Victor, and Witte boon, G. max cv. Williams, Cucumis sativus cv. Straight 8, Solanum lycopericum cv. Reine des Hatives, Vicia faba, Pisum sativum var. macrocarpon, V. unguiculata, and A. americana. The host range of the BCMV isolate on common bean differential species concurred with pathogenicity group I (1) and agreed with assignment as strain NL1. To our knowledge, this is the first complete characterization of a pathotype I strain NL1 of BCMV in the United States, combining biological typing and whole genome sequencing.

References: (1) R. E. Klein et al. Plant Dis. 76:1263, 1992. (2) H. Yamamoto et al. J. Gen. Plant Pathol. 74:97, 2008. (3) L. Zheng et al. PLoS One 3:e1586, 2008.
First Report of Myrothecium roridum Causing Leaf Spot of Anubias barteri var. nana in Mainland China
Authors: Wang J. H. , Wang L. , Cheng H. R. , Cheng W. Z. , Rao G. P. , Cao G. , Zhang M. Q.
Published: August 2014

Anubias barteri var. nana (belonging to family Araceae) is one of the most popular ornamental plants for aquaria. It has slow growth and small attractive ornamental leaves. It originated from West Africa, was first described in 1860 by Heinrich Wilhelm Schott (1), and is now commercially planted widely in southern China. A new disease of A. barteri var. nana was observed on leaves. Approximately 30% of the plants in an ornamental nursery in Baiyun district, Gaungzhou, China (113°22′45.15″ E, 23°23′41.15″ N) in July 2013 were found to be infected. The pathogen caused necrotic spots that progressed to form holes on leaves of the infected plants, negatively affecting their ornamental market value. Eventually the diseased plant died. White fungal fruiting bodies and black sporodochia were observed on the surfaces of the symptomatic leaves. A single-spore isolate (myr5) was obtained from the concentric lesions and cultured on potato dextrose agar (PDA). The floccose fungal colonies were white to buff, and black conidiomata were often visible on the surface after 25 days of incubation. The conidia had rounded ends and the average size of conidia was 5.98 ± 0.15 × 2.24 ± 0.08 μm. The rDNA internal transcribed spacer (ITS) region of isolate myr5 was amplified by PCR using ITS1 and ITS4 primer pairs. The amplified product was sequenced and deposited in GenBank (Accession No. KJ572115) and showed 99% identity to Myrothecium roridum isolates BBA 71015 (AJ302001) and BBA 67679 (AJ301995) (unpublished), and 100% identity to the isolate myr2-2 from Dieffenbachia picta ‘Camilla’ in Taiwan (2). On the basis of morphological and molecular characterization, the fungus causing leaf spot on A. barteri var. nana plants was identified as M. roridum Tode ex Fr (2,3). To confirm the etiology of the disease, Koch's postulates was performed in a greenhouse (28 ± 2°C) using 3-day-old cultures of isolate myr5 and fungal spore suspensions of 1 × 105 conidia ml−1 containing 0.05% of Tween 20. Sixteen healthy leaves, two each from eight plants, were infiltrated on two different parts close to the midribs with 100 μl of the fungal spore using needleless syringes. Water infiltration was used as the control treatment. Water-soaked brown lesions appeared on leaves 7 days after inoculation, followed by the development of dark concentric rings within the necrotic areas on the surface of the inoculated leaves after 15 days of incubation. These symptoms were similar to those in the naturally infected aquarium plants. No symptoms were observed on any of the water micro-infiltrated plants. The fungus was re-isolated from the inoculated plants, but not from control plants. To our knowledge, this is the first report of Myrothecium leaf spot caused by M. roridum on A. barteri var. nana in mainland China.

References: (1) W. Crusio. Primitiae Africanae XII 79 (14):1-48, 1979. (2) C. F. Hong et al. Plant Dis. 97:1253, 2013. (3) M. Tulloch. Mycol. Pap. 130:1-42, 1972.
First Report of Alternaria alternata Causing a Leaf Spot on Philodendron ‘con-go’ in China
Authors: Zhou Z. , Li Y. L. , Yuan C. Y. , Duan P. L.
Published: August 2014

Philodendron ‘con-go’ is widely cultivated indoors in China as an evergreen potted plant. In October 2013, a leaf spot on Philodendron ‘con-go’ was observed in the residential district of Luoyang (112.46° E, 34.62° N), Henan Province, China. The disease was characterized by oval-shaped, 10 to 20 × 25 to 55 mm, yellow to brown lesions with darker brown borders. Fifty potted plants were surveyed, and less than 2% of the leaves were infected. Lesions appeared mostly in old leaves. The symptomatic leaves affected on the plants' ornamental value, but had little impact on their health. Some lesions merged to form a large irregular lesion that could cover a whole leaf. Two infected leaves from one plant were selected randomly for the isolation of the pathogen. Lesions were cut into 1 cm2 pieces, soaked in 70% ethanol for 30 s, sterilized with 1% sodium hypochlorite for 5 min, then washed three times in sterilized distilled water. The pieces were incubated at 25°C on potato dextrose agar (PDA) for 4 to 5 days. A fungus was consistently isolated. Colonies of the fungus were deep green with white mycelium borders. Conidiophores were light brown with 2 to 4 septa. Conidia were obclavate, 14.6 to 49.1 × 8.3 to 16.4 μm, with a short beak, and with 1 to 5 transverse septa and 0 to 3 longitudinal septa, light brown to olive-brown. Based on morphology, the pathogen was identified as Alternaria alternata. Three isolates were selected randomly for further identification. To confirm pathogenicity, eight leaves of potted Philodendron ‘con-go’ plants were wounded with a sterile pin after wiping each leaf surface with 70% ethanol and washing each leaf with sterilized distilled water three times. The isolates were grown on PDA for 7 days and suspended in sterile distilled water to produce a final concentration of 2 × 105 spores/ml. A 5-μl drop of spore suspension was placed on each pin-wounded leaf. Each of three fungal isolates was inoculated on two leaves, and the control treatment (water inoculated) was done similarly on two leaves. The plants were placed in a growth chamber at 28°C with 80% relative humidity, 50 to 60 klx/m2 light intensity, and a 10-h photoperiod. After 7 days, lesions appeared on inoculated leaves, but the control leaves remained symptomless. Pathogenicity tests were repeated three times. Similar disease symptoms and re-isolation of A. alternata fulfilled Koch's postulates. To confirm the fungal identification, the rDNA of the internal transcribed spacer region in three isolates were amplified using primers ITS1 and ITS4 (1) and sequenced. The nucleotide sequence of the ITS region was submitted to GenBank under accession KJ829535 and showed 100% sequence identity with the strain A. alternata LPSC 1187 (KF753947.1). To our knowledge, this is the first report of a leaf spot of Philodendron ‘con-go’ by A. alternate in China.

Reference: (1) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, CA, 1990.
Successful Use of Long‐Acting Octreotide for Intractable Chronic Gastrointestinal Bleeding in Children
Authors: O'Meara Marie , Cicalese Maria P. , Bordugo Andrea , Ambrosi Alessandro , Hadzic Nedim , Mieli‐Vergani Giorgina
Published: August 2014

Background and Aims:

Octreotide reduces splanchnic blood flow and is effective in controlling gastrointestinal bleeding (GIB) caused by portal hypertension. Monthly long‐acting octreotide (OCT‐LAR) with an efficacy and safety profile similar to subcutaneous daily administration presents an attractive option for long‐term therapy. We report our experience with OCT‐LAR for severe/recurrent GIB in children with portal hypertension secondary to chronic liver disease or portal vein thrombosis who were unresponsive to standard interventions.

Methods:

A total of 9 patients, 7 boys, who received OCT‐LAR between 2000 and 2009 were studied retrospectively (median age at first bleeding 21 months, range 1 month–14.5 years). The dose (2.5–20 mg intramuscularly monthly) was extrapolated from that used in adult acromegaly and neuroendocrine tumours (10–60 mg/mo). Response to treatment was assessed by comparing the number of bleeding events, hospital admissions for acute bleeding, and number of blood units required during the year before and year after starting OCT‐LAR.

Results:

OCT‐LAR led to a reduction in the number of bleeding episodes in all of the children and to cessation of bleeding in 7. Two children listed for transplantation because of severe GIB were removed from the list. No serious adverse effects immediately attributable to OCT‐LAR were observed. One child developed growth hormone deficiency and hypothyroidism during a prolonged period of treatment with subcutaneous octreotide before commencing OCT‐LAR.

Conclusions:

OCT‐LAR can control severe intractable recurrent GIB in children with portal hypertension. Prospective randomised controlled trials and pharmacokinetic studies are indicated to establish the optimum dose and length of treatment of OCT‐LAR and confirm its efficacy and long‐term safety in children.
Lack of Clinical Predictors for Low Mineral Density in Children With Celiac Disease
Authors: Trovato Chiara M. , Albanese Carlina V. , Leoni Stefania , Celletti Ilaria , Valitutti Francesco , Cavallini Costanza , Montuori Monica , Barbato Maria , Catalano Carlo , Cucchiara Salvatore
Published: August 2014

Objectives:

Metabolic bone disease remains a significant and common complication of celiac disease (CD). Several studies have demonstrated low bone mineral density (BMD) at the time of CD diagnosis in both children and adults. Low BMD in children and adolescents is defined as an areal BMD <2 SD below the age‐adjusted mean value (z score <−2 SD). The aim of the study was to evaluate the BMD in a pediatric population with CD at diagnosis and to correlate z score value, anti–tissue transglutaminase type 2 antibody (anti‐tTG2) titer, symptoms, and Marsh‐Oberhuber (MO) grading.

Methods:

We enrolled 99 patients with celiac disease (male 35, female 64) ages 4 to 15 years at the diagnosis. All of the patients had positive test results for anti‐tTG2 antibodies and histological lesions graded according to MO classification, and underwent lumbar dual‐energy x‐ray absorptiometry. BMD was estimated by z score.

Results:

Low BMD (z score ≤−2 SD) was found in 13 (13.13%) patients; 22 (22.22%) patients with CD showed −2 < z score ≤ −1; −1 < z score < 0 was found in 41 (41.41%) patients. z score ≥ 0 was detected only in 23 (23.23%) patients with CD. Mean BMD value in patients with CD is z score −0.68. No correlations were found between z score value and anti‐tTG2 titer (Spearman ρ 0.13), between z score value and MO degree (Spearman ρ −0.17), and between z score and symptoms (Spearman ρ −0.10).

Conclusions:

BMD of patients with CD at diagnosis does not seem to correlate with MO degree, anti‐tTG2 titer, and symptoms. At the moment, we do not have clinical predictors for low mineral density in children with CD.
Polyethylene Glycol 4000 for Treatment of Functional Constipation in Children
Authors: Dziechciarz Piotr , Horvath Andrea , Szajewska Hania
Published: August 2014

Objectives:

The aim of the study was to evaluate the effectiveness and safety of 2 different polyethylene glycol (PEG) doses for the maintenance treatment of functional constipation in children.

Methods:

Children with functional constipation according to the Rome III criteria were randomly assigned to receive PEG 4000 at a dose of either 0.7 g/kg (high‐dose group; n = 45) or 0.3 g/kg (low‐dose group; n = 47) for 6 weeks. Adjustment of the therapy was recommended in the event of <3 bowel movements (BM) per week or ≥3 BM per day. The primary outcome measure was treatment success, defined as ≥3 BM per week with no fecal soiling during the last week of the intervention.

Results:

A total of 90 of 92 randomized children, with a mean age of 3.7 ± 2.1 years, completed the study. In the analysis based on allocated treatment, treatment success was similar in both groups (relative risk 0.9, 95% confidence interval 0.78–1.03). Compared with the high‐dose PEG group, the low‐dose PEG group had an increased need for therapy adjustment of borderline significance (relative risk 2.0, 95% confidence interval 1.0–4.2), an increased risk of painful defecation, a lower number of stools per week, and lower parental satisfaction. Adverse events were similar in both groups.

Conclusions:

To achieve treatment success, both tested doses of PEG were equally safe and effective in the treatment of children with functional constipation.
Fecal Microbial Transplant Via Nasogastric Tube for Active Pediatric Ulcerative Colitis
Authors: Suskind David L. , Singh Namita , Nielson Heather , Wahbeh Ghassan
Published: August 2014

Background:

Ulcerative colitis (UC), a chronic inflammatory disease of the large intestine, is characterized by a dysregulated immune reaction. UC is associated with fecal dysbiosis. Human and animal studies support the fact that the gastrointestinal microbiome may trigger the intestinal immune response, resulting in UC. Fecal microbial transplantation (FMT), by changing the gastrointestinal microbiome of patients with UC, may be a therapeutic option.

Methods:

Four patients with moderate symptoms defined by the Pediatric Ulcerative Colitis Activity Index were enrolled in a prospective, open‐label study of FMT via nasogastric tube in pediatric UC (US Food and Drug Administration IND 14942). After the donor and patient evaluation, patients received FMT with follow‐up evaluations at 2, 6, and 12 weeks after transplantation. Study subjects were maintained on their pretransplant medications. The Pediatric Ulcerative Colitis Activity Index score, C‐reactive protein, and stool calprotectin were completed during each study visit.

Results:

Four patients with UC were enrolled (all boys). Ages ranged from 13 to 16 years. Patients tolerated FMT without adverse effects. None of the patients clinically improved with FMT, nor were there any significant changes in stool calprotectin or laboratory values, including C‐reactive protein, albumin, and hematocrit. Three individuals received additional standard medical therapies before the end of the study.

Conclusions:

This study, although showing that single‐dose FMT via nasogastric tube is well tolerated in active pediatric UC, did not show any clinical or laboratory benefit.
Rectal Prolapse and Cystic Fibrosis
Authors: El‐Chammas Khalil I. , Rumman Nisreen , Goh Vi Lier , Quintero Diana , Goday Praveen S.
Published: August 2014

Screening for cystic fibrosis (CF) is suggested in patients with rectal prolapse (RP). Little is known about the association between CF and RP in the era of newborn screening for CF. Our retrospective review showed that 3.6% of patients with RP had CF, and 3.5% of patients with CF had RP. No demographic or clinical factors appear to predict the likelihood of RP in patients with CF. Sweat chloride testing for patients with RP has a low yield in the era of newborn screening but may still need to be considered in children with RP to avoid missing the rare child with CF.
Persistent social interactions beget more pronounced personalities in a desert-dwelling social spider
Authors: Modlmeier Andreas P. , Laskowski Kate L. , DeMarco Alex E. , Coleman Anna , Zhao Katherine , Brittingham Hayley A. , McDermott Donna R. , Pruitt Jonathan N.
Published: August 2014

The
social niche specialization hypothesis
predicts that repeated social interactions will generate social niches within groups, thereby promoting consistent individual differences in behaviour. Current support for this hypothesis is mixed, probably because the importance of social niches is dependent upon the ecology of the species. We test whether repeated interactions among group mates generate consistent individual differences in boldness in the social spider,
Stegodyphus dumicola.
In support of the social niche specialization hypothesis, we found that consistent individual differences in boldness increased with longer group tenure. Interestingly, these differences took longer to appear than in previous work suggesting this species needs more persistent social interactions to shape its behaviour. Recently disturbed colonies were shyer than older colonies, possibly reflecting differences in predation risk. Our study emphasizes the importance of the social environment in generating animal personalities, but also suggests that the pattern of personality development can depend on subtle differences in species' ecologies.
Ontogeny of aerial righting and wing flapping in juvenile birds
Authors: Evangelista Dennis , Cam Sharlene , Huynh Tony , Krivitskiy Igor , Dudley Robert
Published: August 2014

Mechanisms of aerial righting in juvenile chukar partridge (
Alectoris chukar
) were studied from hatching to 14 days-post-hatching (dph). Asymmetric movements of the wings were used from 1 to 8 dph to effect progressively more successful righting behaviour via body roll. Following 8 dph, wing motions transitioned to bilaterally symmetric flapping that yielded aerial righting via nose-down pitch, along with substantial increases in vertical force production during descent. Ontogenetically, the use of such wing motions to effect aerial righting precedes both symmetric flapping and a previously documented behaviour in chukar (i.e. wing-assisted incline running) hypothesized to be relevant to incipient flight evolution in birds. These findings highlight the importance of asymmetric wing activation and controlled aerial manoeuvres during bird development and are potentially relevant to understanding the origins of avian flight.
Frequency-dependent conspecific attraction to food patches
Authors: Beauchamp Guy , Ruxton Graeme D.
Published: August 2014

In many ecological situations, resources are difficult to find but become more apparent to nearby searchers after one of their numbers discovers and begins to exploit them. If the discoverer cannot monopolize the resources, then others may benefit from joining the discoverer and sharing their discovery. Existing theories for this type of conspecific attraction have often used very simple rules for how the decision to join a discovered resource patch should be influenced by the number of individuals already exploiting that patch. We use a mechanistic, spatially explicit model to demonstrate that individuals should not necessarily simply join patches more often as the number of individuals exploiting the patch increases, because those patches are likely to be exhausted soon or joining them will intensify future local competition. Furthermore, we show that this decision should be sensitive to the nature of the resource patches, with individuals being more responsive to discoveries in general and more tolerant of larger numbers of existing exploiters on a patch when patches are resource-rich and challenging to locate alone. As such, we argue that this greater focus on underlying joining mechanisms suggests that conspecific attraction is a more sophisticated and flexible tactic than currently appreciated.
Involvement of different mesotocin (oxytocin homologue) populations in sexual and aggressive behaviours of the brown anole
Authors: Kabelik David , Magruder D. Sumner
Published: August 2014

The oxytocin (OT) family of neuropeptides are known to modulate social behaviours and anxiety in mammals and birds. We investigated cell numbers and neural activity, assessed as Fos induction, within magnocellular and parvocellular populations of neurons producing the OT homologue mesotocin (MT, Ile
8
-oxytocin). This was conducted within the male brown anole lizard,
Anolis sagrei
, following agonistic or courtship encounters with a conspecific. Both neurons colocalizing and not colocalizing corticotropin-releasing factor (CRF) were examined. Parvocellular neurons of the paraventricular nucleus exhibited a positive correlation between courtship frequency and Fos colocalization, regardless of whether they produce just MT or MT + CRF. Magnocellular populations showed only trends towards positive relationships with courtship and no cell populations showed aggression-related Fos induction. These findings are novel because they demonstrate the involvement of MT neurons in male social behaviour, especially in reptiles for whom the involvement of MT in social behaviour was previously unknown.
Average oxidation state of carbon in proteins
Authors: Dick Jeffrey M.
Published: August 2014

The formal oxidation state of carbon atoms in organic molecules depends on the covalent structure. In proteins, the average oxidation state of carbon (ZC) can be calculated as an elemental ratio from the chemical formula. To investigate oxidation–reduction (redox) patterns, groups of proteins from different subcellular locations and phylogenetic groups were selected for comparison. Extracellular proteins of yeast have a relatively high oxidation state of carbon, corresponding with oxidizing conditions outside of the cell. However, an inverse relationship betweenZCand redox potential occurs between the endoplasmic reticulum and cytoplasm. This trend provides support for the hypothesis that protein transport and turnover are ultimately coupled to the maintenance of different glutathione redox potentials in subcellular compartments. There are broad changes inZCin whole-genome protein compositions in microbes from different environments, and in Rubisco homologues, lowerZCtends to occur in organisms with higher optimal growth temperature. Energetic costs calculated from thermodynamic models are consistent with the notion that thermophilic organisms exhibit molecular adaptation to not only high temperature but also the reducing nature of many hydrothermal fluids. Further characterization of the material requirements of protein metabolism in terms of the chemical conditions of cells and environments may help to reveal other linkages among biochemical processes with implications for changes on evolutionary time scales.
Biophysics of protein evolution and evolutionary protein biophysics
Authors: Sikosek Tobias , Chan Hue Sun
Published: August 2014

The study of molecular evolution at the level of protein-coding genes often entails comparing large datasets of sequences to infer their evolutionary relationships. Despite the importance of a protein's structure and conformational dynamics to its function and thus its fitness, common phylogenetic methods embody minimal biophysical knowledge of proteins. To underscore the biophysical constraints on natural selection, we survey effects of protein mutations, highlighting the physical basis for marginal stability of natural globular proteins and how requirement for kinetic stability and avoidance of misfolding and misinteractions might have affected protein evolution. The biophysical underpinnings of these effects have been addressed by models with an explicit coarse-grained spatial representation of the polypeptide chain. Sequence–structure mappings based on such models are powerful conceptual tools that rationalize mutational robustness, evolvability, epistasis, promiscuous function performed by ‘hidden’ conformational states, resolution of adaptive conflicts and conformational switches in the evolution from one protein fold to another. Recently, protein biophysics has been applied to derive more accurate evolutionary accounts of sequence data. Methods have also been developed to exploit sequence-based evolutionary information to predict biophysical behaviours of proteins. The success of these approaches demonstrates a deep synergy between the fields of protein biophysics and protein evolution.
The interplay of cell–cell and cell–substrate adhesion in collective cell migration
Authors: Wang Chenlu , Chowdhury Sagar , Driscoll Meghan , Parent Carole A. , Gupta S. K. , Losert Wolfgang
Published: August 2014

Collective cell migration often involves notable cell–cell and cell–substrate adhesions and highly coordinated motion of touching cells. We focus on the interplay between cell–substrate adhesion and cell–cell adhesion. We show that the loss of cell-surface contact does not significantly alter the dynamic pattern of protrusions and retractions of fast migrating amoeboid cells (
Dictyostelium discoideum
), but significantly changes their ability to adhere to other cells. Analysis of the dynamics of cell shapes reveals that cells that are adherent to a surface may coordinate their motion with neighbouring cells through protrusion waves that travel across cell–cell contacts. However, while shape waves exist if cells are detached from surfaces, they do not couple cell to cell. In addition, our investigation of actin polymerization indicates that loss of cell-surface adhesion changes actin polymerization at cell–cell contacts. To further investigate cell–cell/cell–substrate interactions, we used optical micromanipulation to form cell–substrate contact at controlled locations. We find that both cell-shape dynamics and cytoskeletal activity respond rapidly to the formation of cell–substrate contact.
Haootia quadriformisn. gen., n. sp., interpreted as a muscular cnidarian impression from the Late Ediacaran period (approx. 560 Ma)
Authors: Liu Alexander G. , Matthews Jack J. , Menon Latha R. , McIlroy Duncan , Brasier Martin D.
Published: August 2014

Muscle tissue is a fundamentally eumetazoan attribute. The oldest evidence for fossilized muscular tissue before the Early Cambrian has hitherto remained moot, being reliant upon indirect evidence in the form of Late Ediacaran ichnofossils. We here report a candidate muscle-bearing organism,Haootia quadriformisn. gen., n. sp., from approximately 560 Ma strata in Newfoundland, Canada. This taxon exhibits sediment moulds of twisted, superimposed fibrous bundles arranged quadrilaterally, extending into four prominent bifurcating corner branches.Haootiais distinct from all previously published contemporaneous Ediacaran macrofossils in its symmetrically fibrous, rather than frondose, architecture. Its bundled fibres, morphology, and taphonomy compare well with the muscle fibres of fossil and extant Cnidaria, particularly the benthic Staurozoa.Haootia quadriformisthus potentially provides the earliest body fossil evidence for both metazoan musculature, and for Eumetazoa, in the geological record.