bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural, optical and high pressure electrical resistivity studies of pure NiO and Cu-doped NiO nanoparticles
Authors: Marselin M. Abila , Jaya N. Victor 
Published: April 2016

In this paper, pure NiO and Cu-doped NiO nanoparticles are prepared by co-precipitation method. The electrical resistivity measurements by applying high pressure on pure NiO and Cu-doped NiO nanoparticles were reported. The Bridgman anvil set up is used to measure high pressures up to 8 GPa. These measurements show that there is no phase transformation in the samples till the high pressure is reached. The samples show a rapid decrease in electrical resistivity up to 5 GPa and it remains constant beyond 5 GPa. The electrical resistivity and the transport activation energy of the samples under high pressure up to 8 GPa have been studied in the temperature range of 273–433 K using diamond anvil cell. The temperature versus electrical resistivity studies reveal that the samples behave like a semiconductor. The activation energies of the charge carriers depend on the size of the samples.
Electronic and spectroscopic properties of Ge nanocrystals using diamondoid structures: A density functional theory study
Authors: Abdulsattar Mudar Ahmed 
Published: April 2016

Energetically stable Ge diamondoids are used as building blocks to investigate Ge nanocrystal properties using density functional theory (DFT). Energy gap, HOMO and LUMO of Ge diamondoids vary according to confinement theory with shape fluctuations. Ge diamondoid vibrational force constants reach 2.18 mDyne/Å which is between that of bulk silicon and tin. Ge–Ge vibrational frequencies and reduced masses reach 357.47 cm[Formula: see text] and 41.93 amu, respectively, which are higher than the values of bulk Ge. Size variation of UV–Vis shows that the maximum optical peak moves from 163 nm to nearly 290 nm as the size of Ge diamondoids and molecules increases. The higher peak value approaches that of experimental Ge quantum dots at 300 nm. NMR spectra of Ge diamondoids are analyzed as a function of diamondoid sizes. Our results show that all investigated spectroscopic tools are sensitive to molecular or nanocrystals size. NMR is particularly good size indicator. Natural bond orbital (NBO) population analysis shows present diamondoid bondings differ from ideal [Formula: see text] bonding. The bonding for Ge valence orbitals is in the range [Formula: see text] depending on distance between Ge atom and diamondoid surface. Highest Ge diamondoids vibrational longitudinal optical (LO) mode is blue shifted with respect to experimental bulk value which is the opposite case for C and Si. H surface atom effects on electronic and vibrational properties are discussed.
Between ethnic options and ethnic boundaries – Recent Polish and Turkish migrants' identification with Germany
Authors: Diehl Claudia , Fischer-Neumann Marion , Mühlau Peter 
Published: April 2016

We describe migrants' early patterns of identification with the receiving society and explain why these differ by migrants' origins. Using longitudinal data from a novel survey among recent immigrants from Poland and Turkey in Germany enables us to analyse the nexus between social assimilation, ethnic boundaries and identification more directly than previous studies. Theoretically, we start out from assimilation theory and its assumption that migrants' identification with the receiving country is a consequence of their preceding social and cognitive assimilation and from the literature on ethnic boundaries. Results suggest that Turkish new migrants start out with higher levels of identification with Germany than Poles. Over time, however, their national identification decreases while it increases for Poles. This is partly explained by the fact that Turkish migrants' social assimilation stagnates; more importantly, only Turks perceive more rather than less discrimination and value incompatibility over time. While both groups' identificational integration with the receiving country thus starts out from different conditions, they do not show a fundamentally dissimilar pattern with respect to the consequences of assimilation and discrimination for their national identification. Yet, the negative impact of the latter is stronger for Turks than for Poles, reflecting the greater salience of ethnic boundaries for this group.
Hepcidin in the diagnosis of iron disorders
Authors: Girelli Domenico , Nemeth Elizabeta , Swinkels Dorine W. 
Published: April 2016

Abstract
The discovery of the iron-regulatory hormone hepcidin in 2001 has revolutionized our understanding of iron disorders, and its measurement should advance diagnosis/treatment of these conditions. Although several assays have been developed, a gold standard is still lacking, and efforts toward harmonization are ongoing. Nevertheless, promising applications can already be glimpsed, ranging from the use of hepcidin levels for diagnosing iron-refractory iron deficiency anemia to global health applications such as guiding safe iron supplementation in developing countries with high infection burden.
VCAM-1+ placenta chorionic villi-derived mesenchymal stem cells display potent pro-angiogenic activity
Authors: Du Wenjing , Li Xue , Chi Ying , Ma Fengxia , Li Zongjin , Yang Shaoguang , Song Baoquan , Cui Junjie , Ma Tao , Li Juanjuan , Tian Jianjian , Yang Zhouxin , Feng Xiaoming , Chen Fang , Lu Shihong , Liang Lu , Han Zhi-Bo , Han Zhong-Chao 
Published: April 2016

Abstract
Introduction
Mesenchymal stem cells (MSCs) represent a heterogeneous cell population that is promising for regenerative medicine. The present study was designed to assess whether VCAM-1 can be used as a marker of MSC subpopulation with superior angiogenic potential.

Methods
MSCs were isolated from placenta chorionic villi (CV). The VCAM-1+/− CV-MSCs population were separated by Flow Cytometry and subjected to a comparative analysis for their angiogenic properties including angiogenic genes expression, vasculo-angiogenic abilities on Matrigel in vitro and in vivo, angiogenic paracrine activities, cytokine array, and therapeutic angiogenesis in vascular ischemic diseases.

Results
Angiogenic genes, including HGF, ANG, IL8, IL6, VEGF-A, TGFβ, MMP2 and bFGF, were up-regulated in VCAM-1+CV-MSCs. Consistently, angiogenic cytokines especially HGF, IL8, angiogenin, angiopoitin-2, μPAR, CXCL1, IL-1β, IL-1α, CSF2, CSF3, MCP-3, CTACK, and OPG were found to be significantly increased in VCAM-1+ CV-MSCs. Moreover, VCAM-1+CV-MSCs showed remarkable vasculo-angiogenic abilities by angiogenesis analysis with Matrigel in vitro and in vivo and the conditioned medium of VCAM-1+ CV-MSCs exerted markedly pro-proliferative and pro-migratory effects on endothelial cells compared to VCAM-1−CV-MSCs. Finally, transplantation of VCAM-1+CV-MSCs into the ischemic hind limb of BALB/c nude mice resulted in a significantly functional improvement in comparison with VCAM-1−CV-MSCs transplantation.

Conclusions
VCAM-1+CV-MSCs possessed a favorable angiogenic paracrine activity and displayed therapeutic efficacy on hindlimb ischemia. Our results suggested that VCAM-1+CV-MSCs may represent an important subpopulation of MSC for efficient therapeutic angiogenesis.
A novel method for banking stem cells from human exfoliated deciduous teeth: lentiviral TERT immortalization and phenotypical analysis
Authors: Yin Zhanhai , Wang Qi , Li Ye , Wei Hong , Shi Jianfeng , Li Ang 
Published: April 2016

Abstract
Background
Stem cells from human exfoliated deciduous teeth (SHED) have recently attracted attention as novel multipotential stem cell sources. However, their application is limited due to in vitro replicative senescence. Ectopic expression of telomerase reverse transcriptase (TERT) is a promising strategy for overcoming this replicative senescence. Nevertheless, its potential application and the phenotype as well as tumorigenicity have never been assessed in SHED.

Methods
TERT expression was stably restored in SHED (TERT-SHED) isolated from healthy children aged 6–8 years using lentiviral transduction with a puromycin selection marker. The expression of TERT was detected using reverse transcription polymerase chain reaction, Western blot and immunofluorescence. Surface markers of SHED were detected by flow cytometry. Enzyme-linked immunosorbent assay was used to assess senescence-associated β-galactosidase, while CCK-8 methods were used to examine the proliferation capacity of SHED and TERT-SHED at different passages. Moreover, multilineage differentiation, karyotype, colony formation in soft agar, and tumor formation in nude mice of SHED and TERT-SHED were also examined.

Results
Lentiviral transduction induced stable TERT expression even in SHED at the 40th passage. TERT-SHED showed robust proliferation capacity and low concentration of β-galactosidase. Although they had some different biomarkers than early passage SHED, TERT-SHED at late passage showed similar mutilineage differentiation as TERT at early passage. Moreover, TERT-SHED at late passage showed normal karyotype, no soft agar colony formation, and no tumor formation in nude mice.

Conclusions
TERT-immortalized SHED may be a promising resource for stem-cell therapy, although attention should be paid to the biological behavior of the cells.
Feasibility of approximate broadband estimation of acoustic impedance profile from first principles and band-limited reflection data
Authors: Ghosh Santi Kumar , Mandal Animesh 
Published: April 2016

Because seismic reflection data are band limited, acoustic impedance profiles derived from them are nonunique. The conventional inversion methods counter the nonuniqueness either by stabilizing the answer with respect to an initial model or by imposing mathematical constraints such as sparsity of the reflection coefficients. By making a nominal assumption of an earth model locally consisting of a stack of homogeneous and horizontal layers, we have formulated a set of linear equations in which the reflection coefficients are the unknowns and the recursively integrated seismic trace constitute the data. Drawing only on first principles, the Zoeppritz equation in this case, the approach makes a frontal assault on the problem of reconstructing reflection coefficients from band-limited data. The local layer-cake assumption and the strategy of seeking a singular value decomposition solution of the linear equations counter the nonuniqueness, provided that the objective is to reconstruct a smooth version of the impedance profile that includes only its crude structures. Tests on synthetic data generated from elementary models and from measured logs of acoustic impedance demonstrated the efficacy of the method, even when a significant amount of noise was added to the data. The emergence of consistent estimates of impedance, approximating the original impedance, from synthetic data generated for several frequency bands has inspired our confidence in the method. The other attractive outputs of the method are as follows: (1) an accurate estimate of the impedance mean, (2) an accurate reconstruction of the direct-current (DC) frequency of the reflectivity, and (3) an acceptable reconstruction of the broad outline of the original impedance profile. These outputs can serve as constraints for either more refined inversions or geologic interpretations. Beginning from the restriction of band-limited data, we have devised a method that neither requires a starting input model nor imposes mathematical constraints on the earth reflectivity and still yielded significant and relevant geologic information.
A method for low-frequency noise suppression based on mathematical morphology in microseismic monitoring
Authors: Li Huijian , Wang Runqiu , Cao Siyuan , Chen Yangkang , Huang Weilin 
Published: April 2016

The frequency of microseismic data is higher than that of conventional seismic data. The range of effective frequency is usually from 100 to 500 Hz, and low-frequency noise is a common disturbance in downhole monitoring. Conventional signal analysis techniques, such as band-pass filters, have their limitation in microseismic data processing when the useful signals and noise share the same frequency band. We have developed a novel method to suppress low-frequency noise in microseismic data based on mathematical morphology theory that aims at distinguishing useful signals and noise according to their tiny differences of waveform. By choosing suitable structure elements, we have extracted low-frequency noise from a original data set. We first developed the fundamental principle of mathematical morphology and the formulation of our approach. Then, we used a synthetic data example that was composed of a Ricker wavelet and low-frequency noise to test the feasibility and performance of the proposed approach. Our results from the synthetic example indicate that the proposed approach can effectively suppress large-scale low-frequency noise while slightly decreasing the small-scale signals. Finally, we have applied the proposed approach to field microseismic data and obtained very encouraging results.
Vertical seismic wave gradiometry: Application at the San Andreas Fault Observatory at Depth
Authors: Langston Charles A. , Ayele Mehari Melak 
Published: April 2016

We have developed vertical seismic wave gradiometry (VSWG) to estimate velocity, impedance, and attenuation structure in the vicinity of boreholes using borehole array waveforms of check-shot explosions near the borehole head. We have extended wave gradiometry (WG) theory from a purely local relation of the wavefield and wavefield spatial gradient to one that incorporated the ray ansatz over the length of the borehole for a traveling wave in a vertically inhomogeneous medium. We checked the ray assumption against acoustic full-wave synthetic seismograms, and it was found to yield robust measures of the medium velocity. Anelastic attenuation and impedance structure trade off, but in cases of high anelastic attenuation, realistic bounds can be placed on the seismic impedance that effectively constrains the average attenuation. We have applied these methods to data collected at the San Andreas Fault Observatory at Depth borehole in central California in 2005, and we found that the WG velocity estimate agreed well with the borehole acoustic log and previously determined vertical seismic profile results based on traveltime analysis except at the bottom of the hole, where refraction on a near-vertical fault affected the data. The average [Formula: see text] is approximately 20 in the frequency band of 10–30 Hz, and it is required to yield realistic values of impedance in the local medium. Application of VSWG yields appropriate, smoothed velocity models that can be used as an end product or as a starting model for full-wave inversion.
On the nature of long-period long-duration seismic events detected during hydraulic fracturing
Authors: Zecevic Megan , Daniel Guillaume , Jurick Dana 
Published: April 2016

Long-period long-duration (LPLD) seismic events are low-amplitude tremor-like seismic signals that have been observed in some microseismic monitoring data sets acquired during hydraulic fracturing operations. The LPLD events have been interpreted to be associated with slow slip along preexisting fractures presumed to either have high clay content or be misaligned with respect to the current-day principal stress directions. However, a recent study indicates that regional earthquakes, when recorded on vertical downhole monitoring arrays, have similar signal characteristics to LPLD events and that care must be taken when analyzing and interpreting such signals. Using data from a hydraulic fracturing microseismic data set in which LPLD events have previously been identified and well documented, together with data from the EarthScope Transportable USArray, we have investigated the hypothesis that the documented LPLD events were regional earthquakes. We have determined that the LPLD events corresponded with signals recorded on the USArray at distances of up to 350 km away from the injection well, although they were not listed in any regional earthquake catalog. The spatial coverage of the USArray allows the sources of many of the LPLD events to be relocated outside of the treatment well area and thus suggests that they are regional earthquakes of magnitude smaller than M2.5 rather than locally sourced events related to the hydraulic fracturing stimulation process.
Life form evolution in epidendroid orchids: Ecological consequences of the shift from epiphytism to terrestrial habit in Hexalectris
Authors: Sosa Victoria , Cameron Kenneth M. , Angulo Diego F. , Hernández-Hernández Tania 
Published: April 2016

AbstractGreat diversity of life forms has favored the colonization and dominance of angiosperms in almost every terrestrial habitat. This is certainly the case in the Orchidaceae, in which the diversity of life forms includes epiphytes, terrestrial geophytes and mycoheterotrophs. In this study we investigated the evolution of life form in tribe Epidendreae focusing on the clade comprised of Basiphyllaea, Bletia and Hexalectris. We estimated divergence dates, ancestral areas, patterns of niche evolution and divergence/convergence of climate preferences in order to understand whether shifts in climate preferences can be linked to the evolution of novel life forms, allowing species to extend their distribution ranges into novel habitats. Our analyses corroborated the shift from epiphytism to terrestrial life forms in Epidendreae, which occurred in a clade with Basiphyllaea‐Bletia‐Hexalectris that originated in Mexico and Central America from the Mid‐Eocene to the Oligocene, coincident with the origin of other aridity‐adapted plant groups. Dispersal occurred to North America, South America and the Antilles. Some small aridity‐adapted groups in Hexalectris diverged more recently in the Pliocene and Pleistocene when aridification in North America occurred. Of the climate variables analyzed, annual mean temperature, annual precipitation and precipitation of the wettest month were found to diverge for the terrestrial clade relative to values associated with the other Epidendreae clades. For niche evolution, Ornstein‐Uhlenbeck models indicated that the adaptive optima differed between epiphytes and terrestrial life forms, suggesting a shift of climatic niche between the terrestrial life form clade of Basiphyllaea‐Bletia‐Hexalectris and the rest of the clades with epiphyte life forms. We suggest that the shift to terrestrial life forms, most noticeable in Hexalectris, favored the colonization of novel habitats with a large range of temperatures, extending the distribution of this genus northward.
The Index Seminum: Seeds of change for seed exchange
Authors: Havinga Reinout , Kool Anneleen , Achille Frédéric , Bavcon Jože , Berg Christian , Bonomi Costantino , Burkart Michael , De Meyere Dirk , Hart Joke ’t , Havström Mats , Keßler Paul , Knickmann Barbara , Köster Nils , Martinez Rémy , Ostgaard Havard , Ravnjak Blanka , Scheen Anne-Cathrine , Smith Pamela , Smith Paul , Socher Stephanie A. , Vange Vibekke 
Published: April 2016

AbstractBotanic gardens have been exchanging seeds through seed catalogues for centuries. In many gardens, these catalogues remain an important source of plant material. Living collections have become more relevant for genetic analysis and derived research, since genomics of non‐model organisms heavily rely on living material. The range of species that is made available annually on all seed lists combined, provides an unsurpassed source of instantly accessible plant material for research collections. Still, the Index Seminum has received criticism in the past few decades. The current exchange model dictates that associated data is manually entered into each database. The amount of time involved and the human errors occurring in this process are difficult to justify when the data was initially produced as a report from another database. The authors propose that an online marketplace for seed exchange should be established, with enhanced search possibilities and downloadable accession data in a standardised format. Such online service should preferably be supervised and coordinated by Botanic Gardens Conservation International (BGCI). This manuscript is the outcome of a workshop on July 9th, 2015, at the European botanic gardens congress “Eurogard VII” in Paris, where the first two authors invited members of the botanic garden community to discuss how the anachronistic Index Seminum can be transformed into an improved and modern tool for seed exchange.
Past the Point of Speeding Up: The Negative Effects of Workload Saturation on Efficiency and Patient Severity
Authors: Berry Jaeker Jillian A. , Tucker Anita L. 
Published: April 2016

Service organizations face a trade-off between high utilization and responsiveness. High utilization can improve financial performance, but causes congestion, which increases throughput time. Employees may manage this trade-off by reducing processing times during periods of high workload, resulting in an inverted U-shaped relationship between utilization and throughput time. Using two years of inpatient data from 203 California hospitals, we find evidence that patient length of stay (LOS) increases as occupancy increases, until a tipping point, after which patients are discharged early to alleviate congestion. More interestingly, we find a second tipping point—at 93% occupancy—beyond which additional occupancy leads to a longer LOS. These results are indicative of a workload-related “saturation effect” where employees can no longer overcome high workload by speeding up. Our data suggest that the saturation effect is due to an increase in the workload requirements of the remaining patients. Collectively, we find that the underlying relationship between occupancy and LOS is N-shaped. Consequently, managers who seek cost efficiencies via a strategy of high utilization in tandem with speeding up may find that their strategy backfires because there is a point at which employees are no longer able to compensate for a high workload by working harder, and throughput time counterproductively increases. We perform a counterfactual analysis and find that an alternate strategy of employing flexible labor when faced with high occupancy levels might be a more productive approach, and could save the hospitals in our sample up to $138 million over 23 months. This paper was accepted by Serguei Netessine, operations management.
The User Innovation Paradigm: Impacts on Markets and Welfare
Authors: Gambardella Alfonso , Raasch Christina , von Hippel Eric 
Published: April 2016

Innovation has traditionally been seen as the province of producers. However, theoretical and empirical research now shows that individual users—consumers—are also a major and increasingly important source of new product and service designs. In this paper, we build a microeconomic model of a market that incorporates demand-side innovation and competition. We explain the conditions under which firms find it beneficial to invest in supporting and harvesting users’ innovations, and we show that social welfare rises when firms utilize this source of innovation. Our modeling also indicates reasons for policy interventions with respect to a mixed user and producer innovation economy. From the social welfare perspective, as the share of innovating users in a market increases, profit-maximizing firms tend to switch “too late” from a focus on internal research and development to a strategy of also supporting and harvesting user innovations. Underlying this inefficiency are externalities that the producer cannot capture. Overall, our results explain when and how the proliferation of innovating users leads to a superior division of innovative labor involving complementary investments by users and producers, both benefitting producers and increasing social welfare.This paper was accepted by Lee Fleming, entrepreneurship and innovation.