bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinesthetic Learning Style and Structured Approach to Learning as Most Preferred by Nursing Students
Authors: Ali-Bangcola Ashley
Published: August 2016

The learning process has been the focus of numerous studies, but remains complex and affected by many factors. Since hardly any attention has been paid to how students learn and how teachers teach in many institutions, this quantitative descriptive-correlational study was conducted to determine the learning styles and attitude towards learning of nursing students. A sample of 304 nursing students was selected from all the nursing schools in Marawi City, Philippines using stratified proportionate random sampling technique with replacement. Results revealed that the four learning styles (Visual, Auditory, Tactile, and Kinesthetic) were found to have been used by the students simultaneously as major learning styles and most of them expressing a preference for kinesthetic learning style (78%). On the other hand, they expressed a minor and negligible preference for group Learning. The results of the questionnaire on the attitude towards learning revealed a high level of academic comfort and a preference towards structured, spontaneous, and person-centered approaches to learning. The study concludes that out of the six learning styles tested; only group learning style is found to have no significant relationship with the participantsâ€™ attitude towards learning. Based on the findings, the researcher recommends that faculty members should take into consideration the differences among the students when designing the course material.
Sadtong Panahon: Oral Storytelling Training Course for Pre-Service Teachers
Authors: Carretero Marigrace D. , Bosquillos Jackielyne M. , Ricafort Jhonner D.
Published: August 2016

Storytelling is an art that contributes not only to students' academic success, but also to their emotional well-being. However, not many teachers have skills in storytelling. The reason maybe that they have not been trained in the art, or they lack knowledge of it. The study identified the different reactions of the students during storytelling sessions as observed by the students themselves and the teachers. The study is both quantitative and qualitative in nature. It made use of a descriptive developmental research design. The respondents were 60 students and 60 teachers. Survey questionnaires were used to gather data. Unstructured interviews were also conducted to validate their answers. Results showed that most of the students are bored and do not engage themselves during the storytelling session. This may be attributed to poor skills in forming connections and poor communication skills of the teachers. Based on the findings, it can be concluded that teachers' way of telling a story affects the students' understanding and interest in the story. However, this skill is lacking in most teachers. Varied problems related to these skills are met by the teachers. The researchers recommend that teachers need to improve their communication skills to become effective storytellers and a storytelling training course should be designed and implemented to train pre-service teachers and enhance their storytelling skills.
The Nose-Bleed Syndrome: A Study on the Attitude of the College Students towards English Language Learning and Their Linguistic Self-Confidence in a Multi-Cultural Context
Authors: Berowa Annie Mae
Published: August 2016

The expression "nose-bleed!" has become the most popular expression among Filipinos when asked to speak in English. In the Philippines, English is the most feared language. This fear is seen in classes where students feel so anxious that they may mispronounce a word or that they may commit grammatical inaccuracies. This also happens during job interviews when most of the applicants would sweat out while using English. The study was undertaken to determine the profile of the select students as respondents of the study, their attitude towards English language learning, and the situation/s that they feel linguistically confident in using the target language in a multi-cultural context. The study was conducted at the Mindanao State University (MSU), Main Campus, in the Islamic City of Marawi. The study utilized both quantitative and qualitative data collection and analysis procedures. Survey questionnaire and Focus Group Discussion (FGD) were employed. The questionnaire was administered to 129 randomly selected Job Enabling English Proficiency (JEEP) Program students, and then the FGD was conducted to probe further certain points that require illumination. It was concluded that the respondents have a positive attitude toward learning the English language. It was also disclosed that the linguistic self-confidence of the respondents leaned more on the situation-specific self-confidence.
Electrical Post Fire as Cause of Fire Incidents in Region VI, Philippines
Authors: Occeno Kenneth
Published: August 2016

The devastating electrical fire incidents affect the economy of the country, and it is essential to answer this problem. The intention of the study is to determine the origin of the electrical fire and recommend for possible solutions. The study sought to find out the causes of electrical fire incidents in Region VI that can be used as a guide for future research and policy guidelines relevant to prevention activities. Descriptive method of research, employing frequency count and mean was used in the study. Statistical Package for Social Science was used to generate and analyze the data. The result showed that the number one cause of electrical fire incidents in Region VI was electrical post-fire. Aklan had the highest rate of electrical fire incidents caused by short circuit. Antique had the highest rate of electrical fire incidents caused by overheat while Iloilo and Negros Occidental had the highest rate of incidents caused by electrical post-fire. The structures involved in electrical fire incidents were electrical posts, residential buildings, commercial buildings, vehicles, and other structures. Furthermore, other appliances had the highest involvement followed by electric fans, ceiling fans, flat irons, and electric water heaters. The electrical post-fire and short circuit are mostly the causes of electrical fire incidents.
Lexical Error as Common Interference in Students' Translations Using L2
Authors: Murillo Carwin , Talili Ismael N.
Published: August 2016

Achieving proficiency in writing can only be achieved through successful dealing with content, audience, purpose, word choice, mechanics, syntax and grammar. Mastering any of these areas can be difficult and it takes years of practice and much hard work. The study aimed to analyze the lexico-mechanical elements in students' translations. The results showed that majority of the students committed error as a kind of interference than mistake. Of the two writing elements (lexical and mechanical) considered in the study, the students committed error mostly in lexical element than mechanical. The occurrence of lexical errors is caused by the inappropriateness of the words used in the content that gives meaning. Out of 40 students, 19 committed interference and eight were very much interfered. Interference is present in the students' translations since majority of the students use Cebuano as L1 which is different from L2 concerning the various lexical and mechanical elements. As a result, L1 interference is common in their written English. The study concludes that the difference in written discourse patterns which include the lexical and mechanical elements cause the interference in the composition of the students.
Imaging nuclear, endoplasmic reticulum and plasma membrane events in real time
Authors: Bader Christie A. , Sorvina Alexandra , Simpson Peter V. , Wright Phillip J. , Stagni Stefano , Plush Sally E. , Massi Massimiliano , Brooks Douglas A.
Published: August 2016

Live cell imaging can provide important information on cellular dynamics; however, the full utilisation of this technology has been hampered by the limitations of imaging reagents. Metal‐based complexes have the potential to overcome many of the issues common to many current imaging agents. The rhenium (I)‐based complex fac‐[Re(CO)3(1,10‐phenanthroline)(4‐pyridyltetrazolate)], herein referred to as ReZolve‐ER™, shows promise as a live cell imaging agent with rapid cell uptake, low cytotoxicity, resistance to photobleaching and compatibility with multicolour imaging. ReZolve‐ER™ localised to the nuclear membrane/endoplasmic reticulum (ER) and allowed the detection of exocytotic events at the plasma membrane. Thus, we present a new imaging agent for monitoring live cell events in real time, which is ideal for imaging either short‐ or long‐time courses.
Conserved functions of human Pelota in mRNA quality control of nonstop mRNA
Authors: Ikeuchi Ken , Yazaki Erina , Kudo Kazuhei , Inada Toshifumi
Published: August 2016

Dom34‐Hbs1 plays crucial roles in Nonstop Decay (NSD) and No‐Go Decay (NGD). Here, we report a conserved function of human Pelota (hPelota) in mRNA quality control of nonstop mRNA. hPelota facilitated the expression of the nonstop products from GFP‐Rz mRNA, which lacks a termination codon and a poly(A) tail, in exosome‐defective mutant cells. hPelota promoted the dissociation of stalled ribosomes at the 3′ end of GFP‐Rz mRNA, and mutations in domain A diminished this activity. The hPelota‐R45A mutant associated with ribosomes but was defective in peptide release. Finally, hPelota promoted the degradation of GFP‐Rz mRNA and suppressed the sequential endonucleolytic cleavages caused by stalled ribosomes at the 3′ end of mRNA in dom34∆ mutant cells.
Adenosine A2a receptors form distinct oligomers in protein detergent complexes
Authors: Schonenbach Nicole S. , Rieth Monica D. , Han Songi , O'Malley Michelle A.
Published: August 2016

The human adenosine A2a receptor (A2aR) tunes its function by forming homo‐oligomers and hetero‐oligomers with other G protein‐coupled receptors, but the biophysical characterization of these oligomeric species is limited. Here, we show that upon reconstitution into an optimized mixed micelle system, and purification via an antagonist affinity column, full‐length A2aR exists as a distribution of oligomers. We isolated the dimer population from the other oligomers via size exclusion chromatography and showed that it is stable upon dilution, thus supporting the hypotheses that the A2aR dimer has a defined structure and function. This study presents a crucial enabling step to a detailed biophysical characterization of A2aR homodimers.
ATG15 encodes a phospholipase and is transcriptionally regulated by YAP1 in Saccharomyces cerevisiae
Authors: Ramya Visvanathan , Rajasekharan Ram
Published: August 2016

Phospholipases play a vital role in maintaining membrane phospholipids. In this study, we found that deletion of the three major phospholipases B in Saccharomyces cerevisiae did not affect the hydrolysis of phospholipids, thus suggesting the presence of other, as yet unidentified, phospholipases. Indeed, in silico analysis of the S. cerevisiae genome identified 13 proteins that contain a conserved, putative serine hydrolase motif. In addition, expression profiling revealed that ATG15 (Autophagy 15) was highly expressed in the phospholipase B triple mutant. ATG15 encodes a phospholipase that preferentially hydrolyzes phosphatidylserine. Our analysis of the ATG15 promoter identified binding sites for Yap1p. In vivo and in vitro results showed that Yap1p positively regulates ATG15 expression. Collectively, we demonstrate that Atg15p is a phosphatidylserine lipase and that Yap1p activates the expression of ATG15 during autophagy.
New insights into the interaction between the quorum‐sensing receptor NprR and its DNA target, or the response regulator Spo0F
Authors: Cabrera Rosina , Rodríguez‐Romero Adela , Guarneros Gabriel , de la Torre Mayra
Published: August 2016

The NprR protein and NprRB signaling peptide comprise a bifunctional quorum–sensing system from the Bacillus cereus group that is involved in transcriptional activation through DNA‐binding and in sporulation initiation by binding to Spo0F. We characterized in vitro the direct interactions established by NprR that may be relevant for performing its two functions. Apo‐NprR interacted with Spo0F, but not with the target DNA. The NprRB signaling peptide SSKPDIVG that binds strongly to Apo‐NprR, failed to bind and disrupt the NprR‐Spo0F complex. Finally, the NprR‐NprRB complex bound both to Spo0F and the target DNA with similar affinity. Based on our findings, we propose that rather than a switch triggered by NprRB, the NprR/NprRB ratio and the availability of Spo0F binding sites define the function of NprR.
Hypoxic reprograming of H3K27me3 and H3K4me3 at the INK4A locus
Authors: Chang Soojeong , Park Bongju , Choi Kang , Moon Yunwon , Lee Ho‐Youl , Park Hyunsung
Published: August 2016

Activation of Raf reduces the repressive histone mark H3K27me3 at the INK4a locus by inducing the H3K27me3 demethylase JMJD3. During hypoxia, the catalyitc activity of JMJD3 is reduced due to the limited availability of O2 as a substrate. In our study, we found that hypoxia prevented Raf‐induced JMJD3 from demethylating H3K27me3 at the INK4a locus. Nonetheless, hypoxia did not prevent Raf signaling from inducing INK4a mRNA. Interestingly, we found that hypoxia strongly enhanced the active histone mark H3K4me3 at the INK4a locus by inhibiting the H3K4me3 demethylases JARID1A and JARID1B. Therefore, this study demonstrates that the O2 concentration in the microenvironment differentially affects the repressive methylation on K27 and the activating methylation on K4 at the INK4a locus by inhibiting the H3K27me3 and H3K4me3 demethylases.
Direct observation of the thermal demagnetization of magnetic vortex structures in nonideal magnetite recorders
Authors: Almeida Trevor P. , Muxworthy Adrian R. , Kovács András , Williams Wyn , Nagy Leslei , Conbhuí Pádraig Ó , Frandsen Cathrine , Supakulopas Radchagrit , Dunin‐Borkowski Rafal E.
Published: August 2016

The thermal demagnetization of pseudo‐single‐domain (PSD) magnetite (Fe3O4) particles, which govern the magnetic signal in many igneous rocks, is examined using off‐axis electron holography. Visualization of a vortex structure held by an individual Fe3O4 particle (~250 nm in diameter) during in situ heating is achieved through the construction and examination of magnetic‐induction maps. Stepwise demagnetization of the remanence‐induced Fe3O4 particle upon heating to above the Curie temperature, performed in a similar fashion to bulk thermal demagnetization measurements, revealed that its vortex state remains stable under heating close to its unblocking temperature and is recovered upon cooling with the same or reversed vorticity. Hence, the PSD Fe3O4 particle exhibits thermomagnetic behavior comparable to a single‐domain carrier, and thus, vortex states are considered reliable magnetic recorders for paleomagnetic investigations.
Ice‐flow reorganization in West Antarctica 2.5 kyr ago dated using radar‐derived englacial flow velocities
Authors: Kingslake Jonathan , Martín Carlos , Arthern Robert J. , Corr Hugh F. J. , King Edward C.
Published: August 2016

We date a recent ice‐flow reorganization of an ice divide in the Weddell Sea Sector, West Antarctica, using a novel combination of inverse methods and ice‐penetrating radars. We invert for two‐dimensional ice flow within an ice divide from data collected with a phase‐sensitive ice‐penetrating radar while accounting for the effect of firn on radar propagation and ice flow. By comparing isochronal layers simulated using radar‐derived flow velocities with internal layers observed with an impulse radar, we show that the divide's internal structure is not in a steady state but underwent a disturbance, potentially implying a regional ice‐flow reorganization, 2.5 (1.8–2.9) kyr B.P. Our data are consistent with slow ice flow in this location before the reorganization and the ice divide subsequently remaining stationary. These findings increase our knowledge of the glacial history of a region that lacks dated constraints on late‐Holocene ice‐sheet retreat and provides a key target for models that reconstruct and predict ice‐sheet behavior.
A comparison of the relative effect of the Earth's quasi‐DC and AC electric field on gradient drift waves in large‐scale plasma structures in the polar regions
Authors: Burston Robert , Mitchell Cathryn , Astin Ivan
Published: August 2016

Radio signals traversing polar cap plasma patches and other large‐scale plasma structures in polar regions are prone to scintillation. This implies that irregularities in electron concentration often form within such structures. The current standard theory of the formation of such irregularities is that the primary gradient drift instability drives a cascade from larger to smaller wavelengths that manifest as variations in electron concentration. The electric field can be described as the sum of a quasi‐DC and an AC component. While the effect of the quasi‐DC component has been extensively investigated in theory and by modeling, the contribution of the AC component has been largely neglected. This paper investigates the relative contributions of both components, using data from the Dynamics Explorer 2 satellite. It concludes that the contribution of the AC electric field to irregularity growth cannot be neglected. This has consequences for our understanding of large‐scale plasma structures in polar regions (and any associated radio scintillation) as the AC electric field component varies in all directions. Hence, its effect is not limited to the trailing edge of such structures, as it is for the quasi‐DC component. This raises the need for new experimental and modeling investigations of these phenomena.
Generation of field‐aligned current (FAC) and convection through the formation of pressure regimes: Correction for the concept of Dungey's convection
Authors: Tanaka T. , Watanabe M. , Den M. , Fujita S. , Ebihara Y. , Kikuchi T. , Hashimoto K. K. , Kataoka R.
Published: August 2016

In this paper, we try to elucidate the generation mechanism of the field‐aligned current (FAC) and coexisting convection. From the comparison between the theoretical prediction and the state of numerical solution from the high‐resolution global simulation, we obtain the following conclusions about the distribution of dynamo, the magnetic field structure along the flow path that diverges Poynting flux, and energy conversion promoting the generation of electromagnetic energy. The dynamo for the region 1 FAC, which is in the high‐latitude‐side cusp‐mantle region, has a structure in which magnetic field is compressed along the convection path by the slow mode motion. The dynamo for the region 2 FAC is in the ring current region at the inner edge of the plasma sheet, and has a structure in which magnetic field is curved outward along the convection path. Under these structures, electromagnetic energy is generated from the work done by pressure gradient force, in both dynamos for the region 1 and region 2 FACs. In these generation processes of the FACs, the excitation of convection and the formation of pressure regimes occur as interdependent processes. This structure leads to a modification in the way of understanding the Dungey's convection. Generation of the FAC through the formation of pressure regimes is essential even for the case of substorm onset.
Formation of the inner electron radiation belt by enhanced large‐scale electric fields
Authors: Su Yi‐Jiun , Selesnick Richard S. , Blake J. B.
Published: August 2016

A two‐dimensional bounce‐averaged test particle code was developed to examine trapped electron trajectories during geomagnetic storms with the assumption of conservation of the first and second adiabatic invariants. The March 2013 storm was selected as an example because the geomagnetic activity Kp index sharply increased from 2 + to 7− at 6:00 UT on 17 March. Electron measurements with energies between 37 and 460 keV from the Magnetic Electron Ion Spectrometer (MagEIS) instrument onboard Van Allen Probes (VAP) are used as initial conditions prior to the storm onset and served to validate test particle simulations during the storm. Simulation results help to interpret the observed electron injection as nondiffusive radial transport over a short distance in the inner belt and slot region based on various electric field models, although the quantitative comparisons are not precise. We show that electron drift trajectories are sensitive to the selection of electric field models. Moreover, our simulation results suggest that the actual field strength of penetration electric fields during this storm is stronger than any existing electric field model, particularly for L ≤ 2.
On the reduced geoeffectiveness of solar cycle 24: A moderate storm perspective
Authors: Selvakumaran R. , Veenadhari B. , Akiyama S. , Pandya Megha , Gopalswamy N. , Yashiro S. , Kumar Sandeep , Mäkelä P. , Xie H.
Published: August 2016

The moderate and intense geomagnetic storms are identified for the first 77 months of solar cycles 23 and 24. The solar sources responsible for the moderate geomagnetic storms are indentified during the same epoch for both the cycles. Solar cycle 24 has shown nearly 80% reduction in the occurrence of intense storms whereas it is only 40% in case of moderate storms when compared to previous cycle. The solar and interplanetary characteristics of the moderate storms driven by coronal mass ejection (CME) are compared for solar cycles 23 and 24 in order to see reduction in geoeffectiveness has anything to do with the occurrence of moderate storm. Though there is reduction in the occurrence of moderate storms, the Dst distribution does not show much difference. Similarly, the solar source parameters like CME speed, mass, and width did not show any significant variation in the average values as well as the distribution. The correlation between VBz and Dst is determined, and it is found to be moderate with value of 0.68 for cycle 23 and 0.61 for cycle 24. The magnetospheric energy flux parameter epsilon (ε) is estimated during the main phase of all moderate storms during solar cycles 23 and 24. The energy transfer decreased in solar cycle 24 when compared to cycle 23. These results are significantly different when all geomagnetic storms are taken into consideration for both the solar cycles.
Control of the innermost electron radiation belt by large‐scale electric fields
Authors: Selesnick R. S. , Su Y.‐J. , Blake J. B.
Published: August 2016

Electron measurements from the Magnetic Electron Ion Spectrometer instruments on Van Allen Probes, for kinetic energies ∼100 to 400 keV, show characteristic dynamical features of the innermost (
) radiation belt: rapid injections, slow decay, and structured energy spectra. There are also periods of steady or slowly increasing intensity and of fast decay following injections. Local time asymmetry, with higher intensity near dawn, is interpreted as evidence for drift shell distortion by a convection electric field of magnitude ∼0.4 mV/m during geomagnetically quiet times. Fast fluctuations in the electric field, on the drift time scale, cause inward diffusion. Assuming that they are proportional to changes in Kp, the resulting diffusion coefficient is sufficient to replenish trapped electrons lost by atmospheric scattering. Major electric field increases cause injections by inward electron transport. An injection associated with the June 2015 magnetic storm is consistent with an enhanced field magnitude ∼5 mV/m. Subsequent drift echoes cause spectral structure.
Apparent triggering function of aftershocks resulting from rate‐dependent incompleteness of earthquake catalogs
Authors: Hainzl Sebastian
Published: August 2016

The onset of the aftershock decay after main shocks is controversial. Physical models predict that the onset time is stress dependent, and catalog analysis shows a clear increase of thecvalue of the Omori‐Utsu law with increasing main shock magnitude. However, earthquake catalogs are known to have variable quality and completeness levels; in particular, they miss events directly after main shocks. Thus, it has been also argued that the delayed onset of recorded aftershock activity triggered by large earthquakes is simply an artifact of the time‐varying completeness. Here I utilize a recent approach describing the detection probability of earthquakes as function of the actual earthquake rate. I derive an analytical relation between apparent and true earthquake rate which only depends on the blind time of detection algorithms after the occurrence of an earthquake. This relation is tested and verified for synthetic simulations of Omori‐type aftershock sequences. For a comparison, I analyze earthquake sequences occurred in Southern California and Taiwan, finding that the derived analytical decay function consistently explains the empirical aftershock activity in the catalogs. This indicates that the observed scaling of the Omoricvalue is mainly related to catalog incompleteness and not to any underlying physical process.
Three‐dimensional simulations of fracture dissolution
Authors: Starchenko Vitaliy , Marra Cameron J. , Ladd Anthony J. C.
Published: August 2016

Numerical studies of fracture dissolution are frequently based on two‐dimensional models, where the fracture geometry is represented by an aperture field h(x,y). However, it is known that such models can break down when the spatial variations in aperture are rapid or large in amplitude; for example, in a rough fracture or when instabilities in the dissolution front develop into pronounced channels (or wormholes). Here we report a finite‐volume implementation of a three‐dimensional reactive transport model using the OpenFOAM® toolkit. Extensions to the OpenFOAM source code have been developed which displace and then relax the mesh in response to variations in the surface concentration; up to 100‐fold increases in fracture aperture are possible without remeshing. Our code has simulated field‐scale fractures with physical dimensions of about 10 m. We report simulations of smooth fractures, with small, well‐controlled perturbations in fracture aperture introduced at the inlet. This allows for systematic convergence studies and for detailed comparisons with results from a two‐dimensional model. Initially, the fracture aperture develops similarly in both models, but as local inhomogeneities develop the results start to diverge. We investigate numerically the onset of instabilities in the dissolution of fractures with small random variations in the initial aperture field. Our results show that elliptical cross sections, which are characteristic of karstic conduits, can develop very rapidly, on time scales of 10–20 years in calcite rocks.
Annual cycle and destruction of Eighteen Degree Water
Authors: Billheimer Sam , Talley Lynne D.
Published: August 2016

Eighteen Degree Water (EDW), the subtropical mode water of the western North Atlantic, is a voluminous, weakly stratified upper ocean water mass that acts as a subsurface reservoir of heat, nutrients, and CO2. This thick layer persists throughout the year, but nearly half of its volume is dispersed or mixed away, diffusing its properties into the thermocline, from the time it outcrops in winter until it is renewed the following year. CTD observations from Argo profiling floats and acoustically tracked, isothermally bound profiling floats are used to quantify EDW destruction rates and investigate the relevant processes responsible for the large annual cycle of EDW. EDW destruction occurs primarily at the top of the EDW layer, with the highest EDW destruction rates occurring during early summer. Slower, steadier EDW destruction is observed in early winter. EDW destruction is dominated by 1‐D vertical diffusion, while mesoscale, along‐isopycnal stirring is also significant, explaining approximately 1/3 of the total annual EDW destruction. Destruction via along‐isopycnal processes is more prevalent near the Gulf Stream than in the southern Sargasso Sea, due to higher potential vorticity gradients and enhanced mesoscale activity.
Subsurface morphology and scaling of lunar impact basins
Authors: Miljković K. , Collins G. S. , Wieczorek M. A. , Johnson B. C. , Soderblom J. M. , Neumann G. A. , Zuber M. T.
Published: August 2016

Impact bombardment during the first billion years after the formation of the Moon produced at least several tens of basins. The Gravity Recovery and Interior Laboratory (GRAIL) mission mapped the gravity field of these impact structures at significantly higher spatial resolution than previous missions, allowing for detailed subsurface and morphological analyses to be made across the entire globe. GRAIL‐derived crustal thickness maps were used to define the regions of crustal thinning observed in centers of lunar impact basins, which represents a less unambiguous measure of a basin size than those based on topographic features. The formation of lunar impact basins was modeled numerically by using the iSALE‐2D hydrocode, with a large range of impact and target conditions typical for the first billion years of lunar evolution. In the investigated range of impactor and target conditions, the target temperature had the dominant effect on the basin subsurface morphology. Model results were also used to update current impact scaling relationships applicable to the lunar setting (based on assumed target temperature). Our new temperature‐dependent impact‐scaling relationships provide estimates of impact conditions and transient crater diameters for the majority of impact basins mapped by GRAIL. As the formation of lunar impact basins is associated with the first ~700 Myr of the solar system evolution when the impact flux was considerably larger than the present day, our revised impact scaling relationships can aid further analyses and understanding of the extent of impact bombardment on the Moon and terrestrial planets in the early solar system.
The latitudinal variation of geoelectromagnetic disturbances during large (Dst≤−100 nT) geomagnetic storms
Authors: Woodroffe J. R. , Morley S. K. , Jordanova V. K. , Henderson M. G. , Cowee M. M. , Gjerloev J. G.
Published: August 2016

Geoelectromagnetic disturbances (GMDs) are an important consequence of space weather that can directly impact many types of terrestrial infrastructure. In this paper, we analyze 30 years of SuperMAG magnetometer data from the range of magnetic latitudes 20°≤λ≤75° to derive characteristic latitudinal profiles for median GMD amplitudes. Based on this data, we obtain a parameterization of these latitudinal profiles of different types of GMDs, providing an analytical fit with Dst‐dependent parameters. We also obtain probabilistic estimates for the magnitudes of “100 year” GMDs, finding that
 = 6.9 (3.60–12.9) nT/s should be expected at 45°≤λ < 50°, exceeding the 5 nT/s threshold for dangerous inductive heating.
Preparation of biphenyl‐bridged, crosslinked polyalkoxysilanes: Determination of oil/organic solvent absorption features
Authors: Kizil Soner , Bulbul Sonmez Hayal
Published: August 2016

A novel type of biphenyl‐bridged alkoxysilane‐based crosslinked polyalkoxysilane was prepared by the condensation of 4,4′‐bis(triethoxysilyl)−1,1′‐biphenyl and different lengths of linear aliphatic diols. Fourier transform infrared spectroscopy, solid‐state 13C and 29Si cross‐polarization magic angle spinning nuclear magnetic resonance, and thermogravimetric analysis were used to characterize the biphenyl‐bridged, crosslinked polyalkoxysilanes. The crosslinked polymers were found to have very quick and high swelling capabilities in organic solvents and oils. The absorption–desorption kinetics and reusability features of the crosslinked polymers were also studied, and we found that the synthesized polymers reached their maximum absorption capacity during a variety of tests without losing capacity. We also tested the absorption performance of the sorbents from water surfaces. All of these results confirm that biphenyl‐bridged, crosslinked polyalkoxysilanes could be good candidates as sorbent materials for the cleaning of water from organic contaminants. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44193.
Effect of an alkalized‐modified halloysite on PLA crystallization, morphology, mechanical, and thermal properties of PLA/halloysite nanocomposites
Authors: Guo Jianhua , Qiao Junxia , Zhang Xin
Published: August 2016

Poly(lactic acid) (PLA)/alkalized halloysite nanotube (HNTa) nanocomposites were prepared by melt mixing. The morphology, crystallization behavior, mechanical properties, and thermal stability of the nanocomposites were investigated in comparison with those of the pristine PLA. HNTa can nucleate PLA, leading to a lower recrystallization temperature and higher crystallinity. Infrared spectra revealed that the hydroxyl groups of the PLA interacted with the external hydroxyl groups of HNTa nanofillers via hydrogen bonding. The thermal stability of the nanocomposites was improved with the addition of HNTa. The PLA/HNTa nanocomposites exhibited higher modulus and tensile strength than those of the PLA composites containing unmodified halloysite nanotubes (HNTs). The improvement in properties was probably due to a better dispersion of the HNTa in the PLA matrix compared to that of the unmodified HNTs. Therefore, the facile alkali treatment of HNTs offers a low cost nanofiller for the preparation of PLA based nanocomposites with high tensile modulus and tensile strength. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44272.
Rheology of polyacrylonitrile‐based precursor polymers produced from controlled (RAFT) and conventional polymerization: Its role in solution spinning
Authors: Kaur J. , Millington K. , Cai J.Y.
Published: August 2016

Polymer solutions in dimethyl sulfoxide (DMSO) as a solvent, made from reversible addition fragmentation chain transfer (RAFT)‐mediated polyacrylonitrile (RAFT¥ PAN) terpolymer with molecular weight (MW) of 260,000 g/mol and dispersity (Ð) of 1.29, behave differently under applied shear stress than polymer solutions made from conventional PAN (Control PAN) with similar MW (258,000 g/mol) but Ð of 2.05 in the same solvent. The unique rheology of RAFT PAN is because of the reduced amount of high MW polymer fractions. Specifically, a 25% (w/v) polymer solution of RAFT PAN had a viscosity of 198 Pas while the equivalent control PAN polymer solution had a viscosity of 968 Pas at a shear rate of 1 s−1. Also, RAFT PAN polymer solutions had a longer Newtonian plateau than control PAN polymer solutions. This exhibits more liquid character in RAFT PAN polymer solutions than control PAN polymer solutions at same temperature and concentration. In dynamic tests, RAFT PAN polymer solutions gelled slower than their equivalent control PAN polymer solutions because of their longer polymer chain relaxation times. Slow gelling and higher liquid character in RAFT PAN polymer solutions can result in obtaining stronger and finer precursor fibers during wet spinning. Since RAFT PAN polymer solutions exhibit low viscosity and higher liquid character when compared to its equivalent control PAN at same concentration and temperature, these can allow a wider working window for wet spinning and can also allow higher solid content in the polymer solutions that remain easy to wet spin. This is expected to lead to compact and finer fibers with less voids and higher strength. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44273.
A High‐Temperature Order–Disorder Phase Transition Coupled With Conformational Change in the Hybrid Material [C6H13NH]2⋅ZnBr4
Authors: Khan Tariq , Asghar Muhammad Adnan , Sun Zhihua , Zeb Aurang , Li Lina , Sijie Liu , Zhao Sangen , Ji Chengmin , Luo Junhua
Published: August 2016

A new high‐temperature, hybrid, phase‐transition material, 1‐methylpiperidinium tetrabromozincate (1), that shows a reversible transition at 345 K was synthesized. Differential scanning calorimetry and specific heat capacity measurements confirmed this reversible transformation with a large heat hysteresis of 25 K, which describes a typical first‐order phase transition in 1. The dielectric constant exhibited a steplike anomaly and showed high and low dielectric states in the high‐ and room‐temperature phases, respectively, and therefore, this hybrid might be considered as a potential switchable dielectric material. The variable‐temperature powder X‐ray diffraction patterns displayed remarkable shifts between the experimental patterns at the two different phases. Single‐crystal X‐ray diffraction analyses at various temperatures revealed that the origin of this transformation could be attributed to disordering of the bromine atoms in the anion and the nitrogen atom of the cation. The cation also assumed a conformational change, which was likely induced by the disordered nitrogen atom. The conformational onset of the transformation of the cation from a planar conformer into a relaxed chair also occurred upon decreasing the temperature below transition point; thus, the combined order–disorder and conformational change induced the structural transformation and the change in symmetry.
Heparin's solution structure determined by small‐angle neutron scattering
Authors: Rubinson Kenneth A. , Chen Yin , Cress Brady F. , Zhang Fuming , Linhardt Robert J.
Published: August 2016

Heparin is a linear, anionic polysaccharide that is widely used as a clinical anticoagulant. Despite its discovery 100 years ago in 1916, the solution structure of heparin remains unknown. The solution shape of heparin has not previously been examined in water under a range of concentrations, and here is done so in D2O solution using small‐angle neutron scattering (SANS). Solutions of 10 kDa heparin—in the millimolar concentration range—were probed with SANS. Our results show that when sodium concentrations are equivalent to the polyelectrolyte's charge or up to a few hundred millimoles higher, the molecular structure of heparin is compact and the shape could be well modeled by a cylinder with a length three to four times its diameter. In the presence of molar concentrations of sodium, the molecule becomes extended to nearly its full length estimated from reported X‐ray measurements on stretched fibers. This stretched form is not found in the presence of molar concentrations of potassium ions. In this high‐potassium environment, the heparin molecules have the same shape as when its charges were mostly protonated at pD ≈ 0.5, that is, they are compact and approximately half the length of the extended molecules.
Application of an oxygen‐inducible nar promoter system in metabolic engineering for production of biochemicals in Escherichia coli
Authors: Hwang Hee J. , Kim Jin W. , Ju Si Y. , Park Jin H. , Lee Pyung C.
Published: August 2016

The nar promoter, a dissolved oxygen (DO)‐dependent promoter in Escherichia coli, is simply induced and functional in any cell growth phase, which are advantageous for producing biochemicals/fuels on an industrial scale. To demonstrate the feasibility of using the nar promoter in the metabolic engineering of biochemicals/biofuels in E. coli, three target pathways were examined: the d‐lactate, 2,3‐butandiol (2,3‐BDO), and 1,3‐propanediol (1,3‐PDO) pathways consisting of one, three, and six genes, respectively. Each pathway gene was expressed under the control of the nar promoter. When the ldhD gene was expressed in fed‐batch culture, the titer, yield, and productivity of d‐lactate were 113.12 ± 2.37 g/L, 0.91 ± 0.07 g/g‐glucose, and 4.19 ± 0.09 g/L/h, respectively. When three 2,3‐BDO pathway genes (ilvBN, aldB, bdh1) were expressed in fed‐batch culture, the titer, yield, and productivity of (R,R)‐2,3‐BDO were 48.0 ± 8.48 g/L, 0.43 ± 0.07 g/g glucose, and 0.76 ± 0.13 g/L/h, respectively. When six 1,3‐PDO pathway genes (dhaB1B2B3, yqhD, gdrA, and gdrB) were expressed in fed‐batch culture, the titer, yield, and productivity of 1,3‐PDO were 15.8 ± 0.62 g/L, 0.35 ± 0.01 g/g‐glycerol, and 0.25 ± 0.01 g/L/h, respectively. Based on the reasonable performance comparable to that observed in previous studies using different promoters in metabolic engineering, the nar promoter can serve as a controlled expression tool for developing a microbial system to efficiently produce biochemicals and biofuels. Biotechnol. Bioeng. 2017;114: 468–473. © 2016 Wiley Periodicals, Inc.
Factors for tumor progression in patients with skull base chordoma
Authors: Wang Liang , Tian Kaibing , Wang Ke , Ma Junpeng , Ru Xiaojuan , Du Jiang , Jia Guijun , Zhang Liwei , Wu Zhen , Zhang Junting
Published: August 2016

Skull base chordoma is a rare and fatal disease, recurrence of which is inevitable, albeit variable. We aimed to investigate the clinicopathologic features of disease progression, identify prognostic factors, and construct a nomogram for predicting progression in individual patients. Data of 229 patients with skull base chordoma treated by one institution between 2005 and 2014 were retrieved and grouped as primary and recurrent. Kaplan–Meier survival of progression was estimated, taking competing risks into account. Multivariable Cox regression was used to investigate survival predictors. The primary group consisted by 183 cases, gained more benefits on 5‐year progression‐free survival (PFS) (51%) and mean PFS time (66.9 months) than the recurrent group (46 cases), in which 5‐year postrecurrent PFS was 14%, and mean postrecurrent PFS time was 29.5 months. In the primary group, visual deficits, pathological subtypes, extent of bone invasion, preoperative Karnofsky performance scale (KPS) score, and variation in perioperative KPS were identified as independent predictors of PFS. A nomogram to predict 3‐year and 5‐year PFS consisted of these factors, was well calibrated and had good discriminative ability (adjusted Harrell C statistic, 0.68). In the recurrent group, marginal resection (P = 0.018) and adjuvant radiotherapy (P = 0.043) were verified as protective factors associated with postrecurrent PFS. Factors for tumor progression demonstrated some differences between primary and recurrent cases. The nomogram appears useful for risk stratification of tumor progression in primary cases. Further studies will be necessary to identify the rapid‐growth histopathological subtype as an independent predictor of rapid progression.
Ultrastructure of the ovary and oogenesis in the flatworm Prosthiostomum siphunculus (Polycladida, Cotylea)
Authors: Gammoudi Mehrez , Salvenmoser Willi , Tekaya Saïda , Egger Bernhard
Published: August 2016

Based on light and electron microscopy observations, oogenesis in the cotylean polyclad Prosthiostomum siphunculus was investigated for the first time. The numerous ovarian follicles are dispersed essentially in the dorsal parenchyma. In the follicles, a ventral germinative zone with undifferentiated germs cells of different sizes and a dorsal growth zone with larger growing and abortive oocytes are present. The oogenesis could be subdivided into four stages: (1) Oogonia with a dark nucleus and a dark, ribosome‐rich cytoplasm. (2) Early oocyte stage, represented by relatively small cells (10 μm in diameter), a cytoplasm showing some mitochondria and some endoplasmic reticula. (3) Previtellogenic stage, with a decrease of the nucleo‐cytoplasmic ratio due to the remarkable increase in ooplasm volume. Immature eggshell globules are observed. (4) Vitellogenic stage, including early vitellogenic ovarian stage, in which a second type of globule (inclusion globule) is formed, and a late vitellogenic uterine stage, in which the inclusion globules are not present anymore. The mature eggshell globules form a peripheral layer under the cell membrane. Eggshell and inclusion globules were analyzed with electron energy loss spectroscopy, electron spectroscopic imaging, protease treatment, and with periodic acid thiocarbohydracide silver proteinate to detect polysaccharides. Chromatoid bodies are present in all four stages. For the first time in a flatworm, we provide evidence that accessory cells, forming a tunica around the ovarian follicles, are epithelial or epithelium‐like and likely contribute nutrients for the growth of the oocytes.
Three‐Phase Heterogeneously Catalyzed Oxidative Esterification – Relevance of Oxygen Mass Transport
Authors: Otterstätter Robin , Zanthoff Horst‐Werner , Klemm Elias
Published: August 2016

Oxidative esterification of an aldehyde and an alcohol on a heterogeneous catalyst is a green and mild alternative to classic routes to esters. The reaction of methacrolein with methanol and oxygen to methyl methacrylate is considered. A fixed‐bed catalyst which has a well‐defined core/shell structure and pore size distribution was applied instead of a typically used powder catalyst. It was charged in a fixed‐bed reactor with a recycle for liquids, while the oxygen‐containing gas was fed continuously. The mass transport of the multiphase reaction system is investigated and the results show the different influences like mass transfer through phase boundaries and diffusion limitations of the oxygen mass transport. Different ways are proposed to increase the oxygen mass transfer and decrease diffusion limitations.
Structural and Operational Optimality of Adsorptive Reactors
Authors: Hussainy Mamoon , Agar David W.
Published: August 2016

Adsorptive reactors represent a promising genre of multifunctional reactors combining the highly compatible adsorptive and reactive functionalities. Although they offer multiple benefits to the overall process flowsheet, overcoming the low space time yields, which are an inherent drawback of their cyclic operation, and unwanted functionality interference remain a challenge. The potential of temperature profiling to expedite the macrostructuring of adsorptive reactors for performance optimization is presented. Two industrially relevant reactions have been investigated as test cases: the Claus reaction for recovering sulfur from acid gas and the Deacon reaction for the plant‐internal recycling of chlorine via HCl oxidation.
Improved Insulin Sensitivity With Angiotensin Receptor Neprilysin Inhibition in Individuals With Obesity and Hypertension
Authors: Jordan J , Stinkens R , Jax T , Engeli S , Blaak EE , May M , Havekes B , Schindler C , Albrecht D , Pal P , Heise T , Goossens GH , Langenickel TH
Published: August 2016

Natriuretic peptide (NP) deficiency and sustained renin‐angiotensin system activation are associated with impaired oxidative metabolism and predispose to type‐2 diabetes. We hypothesized that sacubitril/valsartan (LCZ696), which augments NP through neprilysin inhibition while blocking angiotensin II type‐1 (AT1)‐receptors, improves insulin sensitivity, lipid mobilization, and oxidation. After 8 weeks of treatment of obese patients with hypertension, sacubitril/valsartan 400 mg q.d., but not amlodipine 10 mg q.d., was associated with a significant increase from baseline in the insulin sensitivity index (hyperinsulinemic‐euglycemic clamp), and tended to be higher in patients treated with sacubitril/valsartan compared to amlodipine. Abdominal adipose tissue interstitial glycerol concentrations increased with sacubitril/valsartan, but decreased with amlodipine. Whole‐body lipolysis and substrate oxidation did not change with either treatment. Results confirm that sacubitril/valsartan treatment leads to a metabolic benefit in the study population and supports the relevance of neprilysin inhibition along with AT1‐receptor blockade in the regulation of human glucose and lipid metabolism.