bluuebunny/crossref_metadata_2025 huggingface dataset:
DIVERSIDADE E GUILDAS DE REGENERAÇÃO DE ESPÉCIES ARBÓREAS NA BORDA DE UMA FLORESTA NATIVA EM CONTATO COM PLANTIO DE PÍNUS
Authors: Dalla Rosa Angélica , Silva Ana Carolina , Higuchi Pedro , Guidini André Luiz , Spiazzi Fábio Rodrigues , Negrini Marcelo , Ansolin Roni Djeison , Bento Marco Antonio , Gonçalves Didiane Ana , Ferreira Tiago De Souza
Published: July 2015

O objetivo do presente trabalho foi verificar a influência do efeito borda sobre a diversidade e a participação de diferentes guildas de regeneração em um fragmento florestal nativo em contato com reflorestamento de pínus. Para isso, foram amostrados o estrato arbóreo adulto (DAP - diâmetro à altura do peito ≥ 5 cm) e regenerante (altura maior que 15 cm e DAP < 5 cm) em cinco transeções de 20 x 100 m perpendiculares à borda do fragmento. Cada transeção foi subdividida em cinco subparcelas de 20 x 20 m, definindo-se os setores representando o gradiente borda-interior: 0-20 m, 20-40 m, 40-60 m, 60-80 m e 80-100 m. As espécies foram classificadas em guildas de regeneração: pioneira, clímax exigente em luz e clímax tolerante a sombra. Foram determinadas a diversidade (Índice de Shannon) e a abundância das guildas em cada setor e estrato. Os dados foram analisados pelo teste t de Hutcheson e teste de proporção. Enquanto que no estrato adulto não houve variações na diversidade ao longo do gradiente borda-interior, no componente regenerativo a maior diversidade foi observada na borda (0-20 m). Apenas no estrato adulto foram observadas variações na participação relativa das guildas, com maior concentração de indivíduos de pioneiras nos primeiros 40 m.Palavras-chave: Ecologia; fragmentação de hábitats; Floresta Ombrófila Mista. AbstractDiversity and regeneration guilds of tree species in an edge of a natural forest in contact with a pinus plantation. The objective of the present study was to verify the influence of edge-effect on diversity and regeneration guilds participation in a forest fragment in contact with a Pinus plantation. For this, the adult (dbh - diameter at breast height≥5 cm) and regenerative (height higher than 15 and dbh<5 cm) components were sampled in five, 20×100 m, transects perpendiculars to the edge of a fragment. Each transect was subdivided in five, 20×20 m, subplots, defining the following sectors representing the edge-interior gradient: 0-20 m, 20-40 m, 40-60 m, 60-80 m and 80-100 m. The species were classified according to the following regeneration guilds: pioneer, light demanding climax and shade tolerant climax. The diversity (Shannon Index) and guilds abundance in each sector were determined. The data were analyzed by Hutcheson t test and proportion test. While no variation was observed for the adult component, the highest of diversity was observed in the edge (0-20 m) for the regenerative component. Variations along the edge gradient of the relative participation of guilds were observed only for adults, with a concentration of Pioneer within the first 40 m.Keywords: Ecology; habitat fragmentation; Araucaria Forest.
A INFLUÊNCIA DO PIBID-INGLÊS NA FORMAÇÃO DO PROFESSOR REFLEXIVO
Authors: Dos Santos da Silva Gisele , Bittencourt Mushashe Cassiana
Published: July 2015

O presente trabalho tem como objetivo relatar nossa experiência como graduandas do curso de Letras Português/Inglês da Universidade Tecnológica Federal do Paraná e bolsistas do Programa Institucional de Bolsa de Iniciação à Docência (PIBID) de Língua Inglesa e de que forma essa experiência refletiu em nossa formação inicial na carreira docente. Para tanto, primeiramente, descreveremos como se deu o processo de leitura, discussão, preparação e divisão dos bolsistas ainda na Universidade, durante o primeiro semestre do projeto, antes de começarem seus trabalhos devidamente em sala de aula. Em seguida, focaremos em nossa prática de trabalho com gêneros textuais, embasada principalmente na teoria bakhtiniana de gêneros discursivos (BAKHTIN, 1997), em consonância com as considerações acerca dos gêneros textuais apresentadas por Bazerman e Miller (2011) e a proposta de sequência didática de Schneuwly e Dolz (2004). Por fim, traremos uma reflexão acerca da nossa atuação enquanto bolsistas de iniciação à docência no PIBID e como a experiência de participar do projeto contribuiu naquele momento para nossa formação docente inicial.
KRAS-dependent sorting of miRNA to exosomes
Authors: Cha Diana J , Franklin Jeffrey L , Dou Yongchao , Liu Qi , Higginbotham James N , Demory Beckler Michelle , Weaver Alissa M , Vickers Kasey , Prasad Nirpesh , Levy Shawn , Zhang Bing , Coffey Robert J , Patton James G
Published: July 2015

Mutant KRAS colorectal cancer (CRC) cells release protein-laden exosomes that can alter the tumor microenvironment. To test whether exosomal RNAs also contribute to changes in gene expression in recipient cells, and whether mutant KRAS might regulate the composition of secreted microRNAs (miRNAs), we compared small RNAs of cells and matched exosomes from isogenic CRC cell lines differing only in KRAS status. We show that exosomal profiles are distinct from cellular profiles, and mutant exosomes cluster separately from wild-type KRAS exosomes. miR-10b was selectively increased in wild-type exosomes, while miR-100 was increased in mutant exosomes. Neutral sphingomyelinase inhibition caused accumulation of miR-100 only in mutant cells, suggesting KRAS-dependent miRNA export. In Transwell co-culture experiments, mutant donor cells conferred miR-100-mediated target repression in wild-type-recipient cells. These findings suggest that extracellular miRNAs can function in target cells and uncover a potential new mode of action for mutant KRAS in CRC.
Study of planar heterojunction perovskite photovoltaic cells using compact titanium oxide by chemical bath deposition
Authors: Yamamoto Kouhei , Kuwabara Takayuki , Takahashi Kohshin , Taima Tetsuya
Published: July 2015

Spin-coated perovskite solar cells from sol–gels result in high processing costs because of the need for high temperatures. Here, we report a low-temperature spin-coating route to fabricate planar heterojunction perovskite solar cells using chemical bath deposition of compact-TiO
x
layers. Comparison of the solar cell properties of compact-TiO
x
and compact-TiO2 layers show that the power conversion efficiency of the planar heterojunction perovskite solar cell fabricated by the low-temperature, compact-TiO
x
route is comparable to that of conventional TiO2. The chemical bath deposition method requires heating to 150 °C only to form amorphous compact-TiO
x
films compared with the 450 °C required for crystalline anatase compact-TiO2 films.
Optical characterization of different module technologies
Authors: Ebner Rita , Kubicek Bernhard , Újvári Gusztav , Berger Karl
Published: July 2015

For a complete quality control of different module technologies (crystalline and thin film) a combination of fast and non-destructive methods was investigated. Camera-based measurements, such as electroluminescence (EL), photoluminescence (PL), and infrared (IR) technologies, offer excellent possibilities for determining production failures or defects in solar modules, which cannot be detected by means of standard power measurements. These types of optical measurement provide high resolution images with a two-dimensional distribution of the characteristic features of PV modules. This paper focuses on quality control and characterization using EL, PL, and IR imaging with conventional cameras and an alternative excitation source for the PL-setup.
Characteristics of tropopause‐penetrating convection determined by TRMM and COSMIC GPS radio occultation measurements
Authors: Xian Tao , Fu Yunfei
Published: June 2015

Distribution and influence of convection in the upper troposphere and lower stratosphere have been investigated case by case or on regional to global scale. However, previous studies were limited by using proxies for convection or the bias of the tropopause data. Here the tropopause‐penetrating convection is investigated based on the sole use of observational products from Tropical Rainfall Measuring Mission (TRMM) precipitation radar data and Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC). The result shows that the frequency of precipitation‐top heights above the monthly mean tropopause in the tropics is reduced logarithmically if the cold‐point tropopause is adopted instead of the lapse‐rate tropopause. Using the collocated COSMIC and precipitation radar observations, the tropopause‐penetrating convection, i.e., the convection with the precipitation‐top height above the lapse‐rate tropopause, can be found over the summer monsoon regions and some continental regions. The averaged relative precipitation‐top heights of tropopause‐penetrating convective clusters are about 0.2–0.5 km without significant land‐ocean difference, while equivalent radii of clusters are 2.7–3.5 km over land and 0.2–0.5 km larger than those over ocean. These areal and vertical extents are smaller than those reported by previous studies. Furthermore, the collocated temperature profiles show that the tropopause‐penetrating convection generates warming in the upper troposphere and cooling near the lapse‐rate tropopause and in the lower stratosphere. Moreover, the tropopause‐penetrating convection leads to a rapid (within 20 min) lift of the lapse‐rate tropopause by the adiabatic lofting within the convection (within a 10 km radius).
Optimal antenna topologies for spatial gradient detection in differential GNSS
Authors: Jing Jing , Khanafseh Samer , Langel Steven , Chan Fang‐Cheng , Pervan Boris
Published: June 2015

This paper describes new methods to determine optimal reference antenna topologies for detection of spatial gradients in differential Global Navigation Satellite Systems (GNSS). Such gradients can be caused by ionospheric fronts and orbit ephemeris faults, and if undetected, represent major threats to aircraft navigation integrity. Differential carrier phase measurements between ground antennas are highly sensitive to spatial gradients. Therefore, monitors using spatially separated ground antennas have recently attracted great interest. However, they cannot detect gradients of all sizes and directions due to the presence of integer ambiguities. These ambiguities cannot be resolved because the gradient magnitude is unknown a priori. Furthermore, the performance of such monitors is highly dependent on the spatial distribution of reference antennas. In this work, we introduce new methods to find optimized antenna topologies for spatial gradient detection.
Thermal cell structures in the high‐latitude thermosphere induced by ion drag
Authors: Walterscheid R. L. , Crowley G.
Published: June 2015

The occurrence of high‐latitude thermospheric density structures during disturbed conditions that are more complex than the forcing itself suggests that the structure may be caused by a qualitative change in the balance of forces. Using a general circulation model of the thermosphere, we have examined the terms involved in the force balance for levels in the upper and lower thermosphere during active and quiet times and examined the thermal structure in relation to the terms that dominate the balance. A simulation reveals that where ion drag is unable to accelerate the atmosphere into rapid motion the Coriolis force dominates and for fixed pressure levels the centers of cyclonic motion are colder and denser than the surrounding air, while centers of anticyclonic motion are warmer and less dense. At fixed heights, densities are high in the evening anticyclonic gyre and low in the dawn cyclonic gyre. Another simulation reveals that this situation is radically changed when the atmosphere is spun up to rapid motion and the centrifugal force is the dominant inertial force, whence both anticyclones and cyclones become centers of relatively cold high‐density air at fixed pressure levels. On constant height surfaces, cold low‐density centers are found on both the dawnside and duskside with a trough of low‐density air over the pole connecting them. This intrusion of low‐density splits the evening high‐density region that exists under quiet conditions giving the four‐cell pattern found by Crowley et al. (1989a, 1996a, 1996b).
Simulation of polar ozone depletion: An update
Authors: Solomon Susan , Kinnison Doug , Bandoro Justin , Garcia Rolando
Published: June 2015

We evaluate polar ozone depletion chemistry using the specified dynamics version of the Whole Atmosphere Community Climate Model for the year 2011. We find that total ozone depletion in both hemispheres is dependent on cold temperatures (below 192 K) and associated heterogeneous chemistry on polar stratospheric cloud particles. Reactions limited to warmer temperatures above 192 K, or on binary liquid aerosols, yield little modeled polar ozone depletion in either hemisphere. An imposed factor of three enhancement in stratospheric sulfate increases ozone loss by up to 20 Dobson unit (DU) in the Antarctic and 15 DU in the Arctic in this model. Such enhanced sulfate loads are similar to those observed following recent relatively small volcanic eruptions since 2005 and imply impacts on the search for polar ozone recovery. Ozone losses are strongly sensitive to temperature, with a test case cooler by 2 K producing as much as 30 DU additional ozone loss in the Antarctic and 40 DU in the Arctic. A new finding of this paper is the use of the temporal behavior and variability of ClONO2 and HCl as indicators of the efficacy of heterogeneous chemistry. Transport of ClONO2 from the southern subpolar regions near 55–65°S to higher latitudes near 65–75°S provides a flux of NOx from more sunlit latitudes to the edge of the vortex and is important for ozone loss in this model. Comparisons between modeled and observed total column and profile ozone perturbations, ClONO2 abundances, and the rate of change of HCl bolster confidence in these conclusions.
Spatiotemporal patterns of terrestrial gross primary production: A review
Authors: Anav Alessandro , Friedlingstein Pierre , Beer Christian , Ciais Philippe , Harper Anna , Jones Chris , Murray‐Tortarolo Guillermo , Papale Dario , Parazoo Nicholas C. , Peylin Philippe , Piao Shilong , Sitch Stephen , Viovy Nicolas , Wiltshire Andy , Zhao Maosheng
Published: June 2015

Great advances have been made in the last decade in quantifying and understanding the spatiotemporal patterns of terrestrial gross primary production (GPP) with ground, atmospheric, and space observations. However, although global GPP estimates exist, each data set relies upon assumptions and none of the available data are based only on measurements. Consequently, there is no consensus on the global total GPP and large uncertainties exist in its benchmarking. The objective of this review is to assess how the different available data sets predict the spatiotemporal patterns of GPP, identify the differences among data sets, and highlight the main advantages/disadvantages of each data set. We compare GPP estimates for the historical period (1990–2009) from two observation‐based data sets (Model Tree Ensemble and Moderate Resolution Imaging Spectroradiometer) to coupled carbon‐climate models and terrestrial carbon cycle models from the Fifth Climate Model Intercomparison Project and TRENDY projects and to a new hybrid data set (CARBONES). Results show a large range in the mean global GPP estimates. The different data sets broadly agree on GPP seasonal cycle in terms of phasing, while there is still discrepancy on the amplitude. For interannual variability (IAV) and trends, there is a clear separation between the observation‐based data that show little IAV and trend, while the process‐based models have large GPP variability and significant trends. These results suggest that there is an urgent need to improve observation‐based data sets and develop carbon cycle modeling with processes that are currently treated either very simplistically to correctly estimate present GPP and better quantify the future uptake of carbon dioxide by the world's vegetation.
A numerical technique for two‐way radio occultations by oblate axisymmetric atmospheres with zonal winds
Authors: Schinder P. J. , Flasar F. M. , Marouf E. A. , French R. G. , Anabtawi A. , Barbinis E. , Kliore A. J.
Published: June 2015

The Ultra Stable Oscillator aboard the Cassini spacecraft failed in late 2011, which means that all radio occultations after that date have to be done in two‐way mode, using a ground‐based signal transmitted to the spacecraft as the frequency reference. Here we present the numerical technique we use to analyze the data from the two‐way atmospheric radio occultations of both Saturn and Titan that have occurred since the Ultra Stable Oscillator (USO) failure, along with the theoretical reasons behind this technique. Since our two‐way technique is based upon our earlier one‐way technique which used the USO as the frequency reference, we also present our one‐way technique which we used for Saturn occultations prior to the loss of the USO.
High‐resolution Far‐field Microscopy
Authors: Tolstik Elen , Shukla Sapna , Heintzmann Rainer
Published: June 2015

The developments in high‐resolution microscopy play a challenging role in understanding the fundamental processes in molecular and cell‐biology as well as material research. The most desired feature of any optical microscopy technique is the ability to perform in‐depth scanning of specimens and to distinguish extremely small organelles and their dynamics in the nanometer range. To answer a large variety of questions in all areas of biological and material research, it has become imperative to improve the spatial and temporal resolution of optical microscopes. However since the nineteenth century when Ernst Abbe first established the limit of an optical system to resolve two objects – the Abbe diffraction limit – the scientists have been struggling to approach nanometer resolution by defying the diffraction limit. These continued efforts have led to the development of novel super‐resolution technologies in microscopy that are discussed in this review.
Optical Coherence Tomography
Authors: Andersen Peter E.
Published: June 2015

Optical coherence tomography (OCT) is a noninvasive imaging technique that provides real‐time two‐ and three‐dimensional images of scattering samples with micrometer resolution. Mapping the local reflectivity, OCT visualizes the morphology of the sample, in real time or at video rate. In addition, functional properties such as birefringence or blood flow may be detected and used for improved diagnosis. In ophthalmology, OCT is accepted as a clinical standard for diagnosing and monitoring the treatment of a wide range of retinal diseases. With increased image acquisition speed, real‐time or video‐rate imaging is feasible, which has enabled optical microangiography, i.e., visualization of retinal and chorodial blood flow. Such label‐free optical microangiography might be feasible as an adjunct modality to fluorescence‐based angiography. In this review, the fundamental principles of OCT imaging and its main functional extensions are introduced. The part is followed by a discussion of ophthalmic OCT. Finally potential emerging modalities are discussed briefly.
W
igner Function in Optics, The
Authors: Petruccelli Jonathan C. , Alonso Miguel A.
Published: June 2015

In this article, we provide a brief review of the use of the Wigner function in classical optics. Using this mathematical representation, the propagation of light beams through simple optical systems follows rules similar to those of ray optics. Similarly, when applied to optical pulses, the Wigner function allows a description of propagation through dispersive media in a way reminiscent of the propagation of an ensemble of classical particles.
Optical Angular Momentum
Authors: Forbes Andrew , McLaren Melanie
Published: June 2015

That light may possess optical angular momentum is a fact that has been known and exploited for over a hundred years. At first, it was entirely associated with the spin angular momentum of light, through light's polarization. More recently, the orbital angular momentum of light has been studied and exploited for a plethora of applications. This component is associated with the spatial profile of the field. This article outlines the basic concepts of spin and orbital angular momentum, their connectedness through vector beams, and Poincaré sphere representations of optical angular momentum carrying fields and reviews the present state of the field and its many opportunities for advancement.
High activity and wide temperature window of Fe‐Cu‐SSZ‐13 in the selective catalytic reduction of NO with ammonia
Authors: Zhang Tao , Li Jianmei , Liu Jian , Wang Daxi , Zhao Zhen , Cheng Kai , Li Junhua
Published: June 2015

Fe‐Cu‐SSZ‐13 catalysts were prepared by aqueous solution ion‐exchange method based on the one‐pot synthesized Cu‐SSZ‐13. The catalysts were applied to the selective catalytic reduction (SCR) of NO with NH3 and characterized by the means of XRD, UV‐Vis, EPR, XPS, NH3‐TPD, and so on. The selected Fe‐Cu‐SSZ‐13‐1 catalyst exhibited the high NO conversion (>90%) in the wide temperature range (225–625°C), which also showed good N2 selectivity and excellent hydrothermal stability. The results of XPS showed that the Cu and Fe species were in the internal and outer parts of the SSZ‐13 crystals, respectively. The results of UV‐Vis and EPR indicated that the monomeric Cu2+ ions coordinated to three oxygen atoms on the six‐ring sites and Fe monomers are the real active species in the NH3‐SCR reaction. Furthermore, the influence of intracrystalline mass‐transfer limitations on the Fe‐Cu‐SSZ‐13 catalysts is related to the location of active species in the SSZ‐13 crystals. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3825–3837, 2015
Evaluation of pure‐component adsorption properties of silicalite based on the Langmuir and Sips models
Authors: Caravella Alessio , Zito Pasquale F. , Brunetti Adele , Barbieri Giuseppe , Drioli Enrico
Published: June 2015

The Langmuir and Sips models parameters were estimated for the adsorption of several light gases and hydrocarbons (H2, CH4, CO2, CO, N2, C2H6, C3H8, n‐C4H10) in silicalite along with their functionality with temperature. This is a scientific attempt to resume and reconcile the number of available experimental data and supply scientists and other operators with the adsorption properties of silicalite within a wider range of temperature and pressure. Furthermore, to provide readers with more detailed information on where each of the two models work better, the analysis is divided into three temperature ranges: low‐temperature, high‐temperature, and whole temperature range. As a result, it is found that the Langmuir model works well in the whole temperature range for the light gases considered but not for the other hydrocarbons, for which it is better to use the Sips model by splitting calculation over low‐ and high‐temperature range. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3911–3922, 2015
Assessing the performance of an industrial SBCR for Fischer–Tropsch synthesis: Experimental and modeling
Authors: Sehabiague Laurent , Basha Omar M. , Hong Yemin , Morsi Badie , Shi Zhansheng , Jia Haolin , Weng Li , Men Zhuowu , Liu Ke , Cheng Yi
Published: June 2015

The main objective of this study is to predict the performance of an industrial‐scale (ID = 5.8 m) slurry bubble column reactor (SBCR) operating with iron‐based catalyst for Fischer–Tropsch (FT) synthesis, with emphasis on catalyst deactivation. To achieve this objective, a comprehensive reactor model, incorporating the hydrodynamic and mass‐transfer parameters (gas holdup, εG, Sauter‐mean diameter of gas bubbles, d32, and volumetric liquid‐side mass‐transfer coefficients, kLa), and FT as well as water gas shift reaction kinetics, was developed. The hydrodynamic and mass‐transfer parameters for He/N2 gaseous mixtures, as surrogates for H2/CO, were obtained in an actual molten FT reactor wax produced from the same reactor. The data were measured in a pilot‐scale (0.29 m) SBCR under different pressures (4–31 bar), temperatures (380–500 K), superficial gas velocities (0.1–0.3 m/s), and iron‐based catalyst concentrations (0–45 wt %). The data were modeled and predictive correlations were incorporated into the reactor model. The reactor model was then used to study the effects of catalyst concentration and reactor length‐to‐diameter ratio (L/D) on the water partial pressure, which is mainly responsible for iron catalyst deactivation, the H2 and CO conversions and the C5+ product yields. The modeling results of the industrial SBCR investigated in this study showed that (1) the water partial pressure should be maintained under 3 bars to minimize deactivation of the iron‐based catalyst used; (2) the catalyst concentration has much more impact on the gas holdup and reactor performance than the reactor height; and (3) the reactor should be operated in the kinetically controlled regime with an L/D of 4.48 and a catalyst concentration of 22 wt % to maximize C5+ products yield, while minimizing the iron catalyst deactivation. Under such conditions, the H2 and CO conversions were 49.4% and 69.3%, respectively, and the C5+ products yield was 435.6 ton/day. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3838–3857, 2015
Population status of chimpanzees in the Masito‐Ugalla Ecosystem, Tanzania
Authors: Piel Alex K. , Cohen Naomi , Kamenya Shadrack , Ndimuligo Sood A. , Pintea Lilian , Stewart Fiona A.
Published: June 2015

More than 75 percent of Tanzania's chimpanzees live at low densities on land outside national parks. Chimpanzees are one of the key conservation targets in the region and long‐term monitoring of these populations is essential for assessing the overall status of ecosystem health and the success of implemented conservation strategies. We aimed to assess change in chimpanzee density within the Masito‐Ugalla Ecosystem (MUE) by comparing results of re‐walking the same line transects in 2007 and 2014. We further used published remote sensing data derived from Landsat satellites to assess forest cover change within a 5 km buffer of these transects over that same period. We detected no statistically significant decline in chimpanzee density across the surveyed areas of MUE between 2007 and 2014, although the overall mean density of chimpanzees declined from 0.09 individuals/km2in 2007 to 0.05 individuals/km2in 2014. Whether this change is biologically meaningful cannot be determined due to small sample sizes and large, entirely overlapping error margins. It is therefore possible that the MUE chimpanzee population has been stable over this period and indeed in some areas (Issa Valley, Mkanga, Kamkulu) even showed an increase in chimpanzee density. Variation in chimpanzee habitat preference for ranging or nesting could explain variation in density at some of the survey sites between 2007 and 2014. We also found a relationship between increasing habitat loss and lower mean chimpanzee density. Future surveys will need to ensure a larger sample size, broader geographic effort, and random survey design, to more precisely determine trends in MUE chimpanzee density and population size over time. Am. J. Primatol. 77:1027–1035, 2015. © 2015 Wiley Periodicals, Inc.
Screening wild and semi‐free ranging great apes for putative sexually transmitted diseases: Evidence of Trichomonadidae infections
Authors: Rushmore Julie , Allison Andrew B. , Edwards Erin E. , Bagal Ujwal , Altizer Sonia , Cranfield Mike R. , Glenn Travis C. , Liu Hsi , Mudakikwa Antoine , Mugisha Lawrence , Muller Martin N. , Stumpf Rebecca M. , Thompson Melissa Emery , Wrangham Richard , Yabsley Michael J.
Published: June 2015

Sexually transmitted diseases (STDs) can persist endemically, are known to cause sterility and infant mortality in humans, and could have similar impacts in wildlife populations. African apes (i.e., chimpanzees, bonobos, and to a lesser extent gorillas) show multi‐male mating behavior that could offer opportunities for STD transmission, yet little is known about the prevalence and impact of STDs in this endangered primate group. We used serology and PCR‐based detection methods to screen biological samples from wild and orphaned eastern chimpanzees and gorillas (N = 172 individuals, including adults, and juveniles) for four classes of pathogens that either commonly cause human STDs or were previously detected in captive apes: trichomonads, Chlamydia spp., Treponema pallidum (syphilis and yaws), and papillomaviruses. Based on results from prior modeling and comparative research, we expected STD prevalence to be highest in females versus males and in sexually mature versus immature individuals. All samples were negative for Chlamydia, Treponema pallidum, and papillomaviruses; however, a high percentage of wild chimpanzee urine and fecal samples showed evidence of trichomonads (protozoa). Analysis revealed that females were more likely than males to have positive urine—but not fecal—samples; however, there was no evidence of age (sexual maturity) differences in infection status. Sequence analysis of chimpanzee trichomonad samples revealed a close relationship to previously described trichomonads within the genus Tetratrichomonas. Phylogenetic comparisons to archived sequences from multiple vertebrate hosts suggests that many of the chimpanzee parasites from our study are likely transmitted via fecal‐oral contact, but the transmission of some Tetratrichomonas sequence‐types remains unknown and could include sexual contact. Our work emphasizes that only a fraction of infectious agents affecting wild apes are presently known to science, and that further work on great ape STDs could offer insights for the management of endangered great apes and for understanding human STD origins. Am. J. Primatol. 77:1075–1085, 2015. © 2015 Wiley Periodicals, Inc.
Vier Jahrzehnte Chemie der planar hyperkoordinierten Verbindungen
Authors: Yang Li‐Ming , Ganz Eric , Chen Zhongfang , Wang Zhi‐Xiang , Schleyer Paul von Ragué
Published: June 2015

Planar vierfach koordinierter Kohlenstoff (ptC) wurde seit 1874 für über ein Jahrhundert als unplausibel angesehen. Danach konnten jedoch Beispiele rechnerisch vorhergesagt und experimentell realisiert werden. Sowohl elektronische als auch mechanische Effekte (z. B. in kleinen Ringen und Käfigen) stabilisieren diese ungewöhnlichen Bindungsanordnungen. Konzepte basierend auf den Bindungsmotiven des planaren Methans/planaren Methandikations können erweitert werden, um planar hyperkoordinierte Strukturen anderer chemischer Elemente zu entwerfen. Zahlreiche Konfigurationen von verschiedenen Zentralatomen (Haupt‐ und Übergangsmetallelementen) in einer Ebene mit Koordinationszahlen von bis zu zehn werden diskutiert. Die Evolution von solchen planaren Konfigurationen aus kleinen Molekülen zu Clustern, nanoskopischen Spezies bis hin zu Festkörpern wird aufgezeigt. Für einige experimentell hergestellte planare Materialien wurden außergewöhnliche elektrische und magnetische Eigenschaften nachgewiesen.
Direct Synthesis of Chiral Allenoates from the Asymmetric CH Insertion of α‐Diazoesters into Terminal Alkynes
Authors: Tang Yu , Chen Quangang , Liu Xiaohua , Wang Gang , Lin Lili , Feng Xiaoming
Published: June 2015

The asymmetric CH insertion of α‐diazoesters into 1‐alkynes was achieved using chiral cationic guanidinium salts and copper(I) complexes. Optically active 2,4‐disubstituted allenoates were generated under mild reaction conditions from various α‐diazoesters and 1‐alkynes in high yield (up to 99 %) and enantioselectivity (up to 97:3 e.r.). Control experiments excluded the possibility of an asymmetric isomerization of alkynoates.
Metallocorroles as Photocatalysts for Driving Endergonic Reactions, Exemplified by Bromide to Bromine Conversion
Authors: Mahammed Atif , Gross Zeev
Published: June 2015

Photochemical oxidation of halide anions by visible light has been suggested for solar energy conversion processes. Post‐transition metallocorroles are now disclosed as very efficient catalysts for the photoinduced transformation of bromide to bromine. The advantages of these catalysts are that they are very stable under the reaction conditions and that the energy levels of the oxidizing HOMO and the reducing LUMO are easily tuned. Insights into the mechanism of action obtained in this work is predicted to be very useful for the design of other systems that rely on photocatalysis for driving endergonic reactions.
Energy Storage Materials from Nature through Nanotechnology: A Sustainable Route from Reed Plants to a Silicon Anode for Lithium‐Ion Batteries
Authors: Liu Jun , Kopold Peter , van Aken Peter A. , Maier Joachim , Yu Yan
Published: June 2015

Silicon is an attractive anode material in energy storage devices, as it has a ten times higher theoretical capacity than its state‐of‐art carbonaceous counterpart. However, the common process to synthesize silicon nanostructured electrodes is complex, costly, and energy‐intensive. Three‐dimensional (3D) porous silicon‐based anode materials have been fabricated from natural reed leaves by calcination and magnesiothermic reduction. This sustainable and highly abundant silica source allows for facile production of 3D porous silicon with very good electrochemical performance. The obtained silicon anode retains the 3D hierarchical architecture of the reed leaf. Impurity leaching and gas release during the fabrication process leads to an interconnected porosity and the reductive treatment to an inside carbon coating. Such anodes show a remarkable Li‐ion storage performance: even after 4000 cycles and at a rate of 10 C, a specific capacity of 420 mA h g−1 is achieved.
Controlled Anisotropic Growth of Co‐Fe‐P from Co‐Fe‐O Nanoparticles
Authors: Mendoza‐Garcia Adriana , Zhu Huiyuan , Yu Yongsheng , Li Qing , Zhou Lin , Su Dong , Kramer Matthew J. , Sun Shouheng
Published: June 2015

A facile approach to bimetallic phosphides, Co‐Fe‐P, by a high‐temperature (300 °C) reaction between Co‐Fe‐O nanoparticles and trioctylphosphine is presented. The growth of Co‐Fe‐P from the Co‐Fe‐O is anisotropic. As a result, Co‐Fe‐P nanorods (from the polyhedral Co‐Fe‐O nanoparticles) and sea‐urchin‐like Co‐Fe‐P (from the cubic Co‐Fe‐O nanoparticles) are synthesized with both the nanorod and the sea‐urchin‐arm dimensions controlled by Co/Fe ratios. The Co‐Fe‐P structure, especially the sea‐urchin‐like (Co0.54Fe0.46)2P, shows enhanced catalysis for the oxygen evolution reaction in KOH with its catalytic efficiency surpassing the commercial Ir catalyst. Our synthesis is simple and may be readily extended to the preparation of other multimetallic phosphides for important catalysis and energy storage applications.
Reduktive Insertion von elementaren Chalkogenen in Bor‐Bor‐ Mehrfachbindungen
Authors: Braunschweig Holger , Dellermann Theresa , Ewing William C. , Kramer Thomas , Schneider Christoph , Ullrich Stefan
Published: June 2015

Die Synthese schwefel‐ und selenverbrückender Ringsysteme, die durch N‐heterocyclische Carbene stabilisierte Boreinheiten enthalten, gelang durch reduktive Insertion von elementaren Chalkogenen in Bor‐Bor‐Mehrfachbindungen. Die drei bindenden Elektronenpaare zwischen den Boratomen eines Diborins ermöglichen eine Sechs‐Elektronen‐Reduktion und führen zur Bildung eines [2.2.1]‐Bicyclus, in welchem die Brückenkopf‐Boratome durch drei Chalkogenbrücken überspannt sind. Eine ähnliche Reaktion an einem Diboren (Bor‐Bor‐Doppelbindung) führt zu einer reduktiven Übertragung der beiden bindenden Elektronenpaare auf drei Schwefelatome unter Bildung eines NHC‐stabilisierten Trisulfidodiborolans. Der Nachweis dieser Sechs‐ bzw. Vier‐Elektronen‐Reduktionen stützt die Beschreibung von Diborenen bzw. Diborinen mit zwei bzw. drei bindenden Elektronenpaaren – eine Tatsache, die in zukünftigen Diskussionen zur Bindungsordnung nützlich sein könnte.
Integrating NiCo Alloys with Their Oxides as Efficient Bifunctional Cathode Catalysts for Rechargeable Zinc–Air Batteries
Authors: Liu Xien , Park Minjoon , Kim Min Gyu , Gupta Shiva , Wu Gang , Cho Jaephil
Published: June 2015

The lack of high‐efficient, low‐cost, and durable bifunctional electrocatalysts that act simultaneously for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) is currently one of the major obstacles to commercializing the electrical rechargeability of zinc–air batteries. A nanocomposite CoO‐NiO‐NiCo bifunctional electrocatalyst supported by nitrogen‐doped multiwall carbon nanotubes (NCNT/CoO‐NiO‐NiCo) exhibits excellent activity and stability for the ORR/OER in alkaline media. More importantly, real air cathodes made from the bifunctional NCNT/CoO‐NiO‐NiCo catalysts further demonstrated superior performance to state‐of‐the‐art Pt/C or Pt/C+IrO2 catalysts in primary and rechargeable zinc–air batteries.
Catalytic Stereoinversion of L‐Alanine to Deuterated D‐Alanine
Authors: Moozeh Kimia , So Soon Mog , Chin Jik
Published: June 2015

A combination of an achiral pyridoxal analogue and a chiral base has been developed for catalytic deuteration of L‐alanine with inversion of stereochemistry to give deuterated D‐alanine under mild conditions (neutral pD and 25 °C) without the use of any protecting groups. This system can also be used for catalytic deuteration of D‐alanine with retention of stereochemistry to give deuterated D‐alanine. Thus a racemic mixture of alanine can be catalytically deuterated to give an enantiomeric excess of deuterated D‐alanine. While catalytic deracemization of alanine is forbidden by the second law of thermodynamics, this system can be used for catalytic deracemization of alanine with deuteration. Such green and biomimetic approach to catalytic stereocontrol provides insights into efficient amino acid transformations.
Influence of Guest Exchange on the Magnetization Dynamics of Dilanthanide Single‐Molecule‐Magnet Nodes within a Metal–Organic Framework
Authors: Zhang Xuejing , Vieru Veacheslav , Feng Xiaowen , Liu Jun‐Liang , Zhang Zhenjie , Na Bo , Shi Wei , Wang Bing‐Wu , Powell Annie K. , Chibotaru Liviu F. , Gao Song , Cheng Peng , Long Jeffrey R.
Published: June 2015

Multitopic organic linkers can provide a means to organize metal cluster nodes in a regular three‐dimensional array. Herein, we show that isonicotinic acid N‐oxide (HINO) serves as the linker in the formation of a metal–organic framework featuring Dy2 single‐molecule magnets as nodes. Importantly, guest solvent exchange induces a reversible single‐crystal to single‐crystal transformation between the phases Dy2(INO)4(NO3)2⋅2 solvent (solvent=DMF (Dy2‐DMF), CH3CN (Dy2‐CH3CN)), thereby switching the effective magnetic relaxation barrier (determined by ac magnetic susceptibility measurements) between a negligible value for Dy2‐DMF and 76 cm−1 for Dy2‐CH3CN. Ab initio calculations indicate that this difference arises not from a significant change in the intrinsic relaxation barrier of the Dy2 nodes, but rather from a slowing of the relaxation rate of incoherent quantum tunneling of the magnetization by two orders of magnitude.
Hydrophobic Cysteine Poly(disulfide)‐based Redox‐Hypersensitive Nanoparticle Platform for Cancer Theranostics
Authors: Wu Jun , Zhao Lili , Xu Xiaoding , Bertrand Nicolas , Choi Won II , Yameen Basit , Shi Jinjun , Shah Vishva , Mulvale Matthew , MacLean James L. , Farokhzad Omid C.
Published: June 2015

Selective tumor targeting and drug delivery are critical for cancer treatment. Stimulus‐sensitive nanoparticle (NP) systems have been designed to specifically respond to significant abnormalities in the tumor microenvironment, which could dramatically improve therapeutic performance in terms of enhanced efficiency, targetability, and reduced side‐effects. We report the development of a novel L‐cysteine‐based poly (disulfide amide) (Cys‐PDSA) family for fabricating redox‐triggered NPs, with high hydrophobic drug loading capacity (up to 25 wt % docetaxel) and tunable properties. The polymers are synthesized through one‐step rapid polycondensation of two nontoxic building blocks: L‐cystine ester and versatile fatty diacids, which make the polymer redox responsive and give it a tunable polymer structure, respectively. Alterations to the diacid structure could rationally tune the physicochemical properties of the polymers and the corresponding NPs, leading to the control of NP size, hydrophobicity, degradation rate, redox response, and secondary self‐assembly after NP reductive dissociation. In vitro and in vivo results demonstrate these NPs’ excellent biocompatibility, high selectivity of redox‐triggered drug release, and significant anticancer performance. This system provides a promising strategy for advanced anticancer theranostic applications.
A Near‐Infrared‐Emissive Alkynyl‐Protected Au24 Nanocluster
Authors: Wan Xian‐Kai , Xu Wen Wu , Yuan Shang‐Fu , Gao Yi , Zeng Xiao‐Cheng , Wang Quan‐Ming
Published: June 2015

An alkynyl‐protected gold nanocluster [Au24(CCPh)14(PPh3)4](SbF6)2 has been prepared by a direct reduction method. Single‐crystal X‐ray diffraction reveals that the molecular structure contains a Au22 core that is made of two Au13‐centered cuboctahedra that share a square face. Two staple‐like PhCCAuCCPh motifs are located around the center of the rod‐like Au22 core. This Au24 nanocluster is highly emissive in the near‐infrared region with λmax=925 nm and the nature of the HOMO–LUMO transition is investigated by time‐dependent DFT calculations.
Protonation‐Dependent Base Flipping at Neutral pH in the Catalytic Triad of a Self‐Splicing Bacterial Group II Intron
Authors: Pechlaner Maria , Donghi Daniela , Zelenay Veronika , Sigel Roland K. O.
Published: June 2015

NMR spectroscopy has revealed pH‐dependent structural changes in the highly conserved catalytic domain 5 of a bacterial group II intron. Two adenines with pKa values close to neutral pH were identified in the catalytic triad and the bulge. Protonation of the adenine opposite to the catalytic triad is stabilized within a G(syn)–AH+(anti) base pair. The pH‐dependent anti‐to‐syn flipping of this G in the catalytic triad modulates the known interaction with the linker region between domains 2 and 3 (J23) and simultaneously the binding of the catalytic Mg2+ ion to its backbone. Hence, this here identified shifted pKa value controls the conformational change between the two steps of splicing.
Intracellular Self‐Assembly of Taxol Nanoparticles for Overcoming Multidrug Resistance
Authors: Yuan Yue , Wang Lin , Du Wei , Ding Zhanling , Zhang Jia , Han Tao , An Linna , Zhang Huafeng , Liang Gaolin
Published: June 2015

Multidrug resistance (MDR) remains the biggest challenge in treating cancers. Herein we propose the intracellular self‐assembly of nanodrugs as a new strategy for overcoming MDR. By employing a biocompatible condensation reaction, we rationally designed a taxol derivative Ac‐Arg‐Val‐Arg‐Arg‐Cys(StBu)‐Lys(taxol)‐2‐cyanobenzothiazole (CBT‐Taxol) which could be subjected to furin‐controlled condensation and self‐assembly of taxol nanoparticles (Taxol‐NPs). In vitro and in vivo studies indicated that, compared with taxol, CBT‐Taxol showed a 4.5‐fold or 1.5‐fold increase in anti‐MDR effects, respectively, on taxol‐resistant HCT 116 cancer cells or tumors without being toxic to the cells or the mice. Our results demonstrate that structuring protease‐susceptible agents and assembling them intracellularly into nanodrugs could be a new optimal strategy for overcoming MDR.
A Phosphine‐Coordinated Boron‐Centered Gomberg‐Type Radical
Authors: Rosenthal Amos J. , Devillard Marc , Miqueu Karinne , Bouhadir Ghenwa , Bourissou Didier
Published: June 2015

The P‐coordinated boryl radical [Ph2P(naphthyl)BMes]. (Mes=mesityl) was prepared by (electro)chemical reduction of the corresponding borenium salt or bromoborane. Electron paramagnetic resonance (EPR) analysis in solution and DFT calculations indicate large spin density on boron (60–70 %) and strong P–B interactions (P→B σ donation and B→P negative hyperconjugation). The radical is persistent in solution and participates in a Gomberg‐type dimerization process. The associated quinoid‐type dimer has been characterized by single‐crystal X‐ray diffraction.
Metal‐Free Radical [2+2+1] Carbocyclization of Benzene‐Linked 1,n‐Enynes: Dual C(sp3)H Functionalization Adjacent to a Heteroatom
Authors: Hu Ming , Fan Jian‐Hong , Liu Yu , Ouyang Xuan‐Hui , Song Ren‐Jie , Li Jin‐Heng
Published: June 2015

A new metal‐free oxidative radical [2+2+1] carbocyclization of benzene‐linked 1,n‐enynes with two C(sp3)H bonds adjacent to the same heteroatom is described. This method achieves two C(sp3)H oxidative functionalizations and an annulation, thus providing efficient and general access to a variety of fused five‐membered carbocyclic hydrocarbons.
Cobalt Boryl Complexes: Enabling and Exploiting Migratory Insertion in Base‐Metal‐Mediated Borylation
Authors: Frank René , Howell James , Campos Jésus , Tirfoin Rémi , Phillips Nicholas , Zahn Stefan , Mingos D. Michael P. , Aldridge Simon
Published: June 2015

Cobalt boryl complexes, which have only been sporadically reported, can be accessed systematically with remarkable (but controllable) variation in the nature of the MB bond. Complexes incorporating a very strong trans σ‐donor display unparalleled inertness, reflected in retention of the MB bond even in the presence of extremely strong acid. By contrast, the use of the strong π‐acceptor CO in the trans position, results in significant CoB elongation and to labilization of the boryl ligand via unprecedented CO migratory insertion. Such chemistry provides a pathway for the generation of coordinative unsaturation, thereby enabling ligand substitution and/or substrate assimilation. Alkene functionalization by boryl transfer, a well‐known reaction for noble metals such as Rh or Pt, can thus be effected by an 18‐electron base‐metal complex.
Four Decades of the Chemistry of Planar Hypercoordinate Compounds
Authors: Yang Li‐Ming , Ganz Eric , Chen Zhongfang , Wang Zhi‐Xiang , Schleyer Paul von Ragué
Published: June 2015

The idea of planar tetracoordinate carbon (ptC) was considered implausible for a hundred years after 1874. Examples of ptC were then predicted computationally and realized experimentally. Both electronic and mechanical (e.g., small rings and cages) effects stabilize these unusual bonding arrangements. Concepts based on the bonding motifs of planar methane and the planar methane dication can be extended to give planar hypercoordinate structures of other chemical elements. Numerous planar configurations of various central atoms (main‐group and transition‐metal elements) with coordination numbers up to ten are discussed herein. The evolution of such planar configurations from small molecules to clusters, to nanospecies and to bulk solids is delineated. Some experimentally fabricated planar materials have been shown to possess unusual electrical and magnetic properties. A fundamental understanding of planar hypercoordinate chemistry and its potential will help guide its future development.
Two‐Dimensional Layered Heterostructures Synthesized from Core–Shell Nanowires
Authors: Zhang Qi , Xiao Xu , Zhao Ruiqi , Lv Danhui , Xu Guanchen , Lu Zhixing , Sun Lifei , Lin Shizhe , Gao Xiang , Zhou Jun , Jin Chuanhong , Ding Feng , Jiao Liying
Published: June 2015

Controlled stacking of different two‐dimensional (2D) atomic layers will greatly expand the family of 2D materials and broaden their applications. A novel approach for synthesizing MoS2/WS2 heterostructures by chemical vapor deposition has been developed. The successful synthesis of pristine MoS2/WS2 heterostructures is attributed to using core–shell WO3−x/MoO3−x nanowires as a precursor, which naturally ensures the sequential growth of MoS2 and WS2. The obtained heterostructures exhibited high crystallinity, strong interlayer interaction, and high mobility, suggesting their promising applications in nanoelectronics. The stacking orientations of the two layers were also explored from both experimental and theoretical aspects. It is elucidated that the rational design of precursors can accurately control the growth of high‐quality 2D heterostructures. Moreover, this simple approach opens up a new way for creating various novel 2D heterostructures by using a large variety of heteronanomaterials as precursors.