bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanocrystalline Iron Monosulfides Near Stoichiometry
Authors: Roberts Dennice M. , Landin Alyssa R. , Ritter Timothy G. , Eaves Joel D. , Stoldt Conrad R. 
Published: April 2018

AbstractSolids composed of iron and sulfur are earth abundant and nontoxic, and can exhibit interesting and technologically important optical, electronic, and magnetic phenomena. However, the iron-sulfur (Fe-S) phase diagram is congested in regions of slight non-stoichiometric iron vacancies, and even when the iron atomic composition changes by even a few percent at standard temperature and pressure, there are myriad stable crystal phases that form with qualitatively different electronic properties. Here, we synthesized and characterized nanocrystals of the pyrrhotite-4M structure (Fe7S8) in an anhydrous oleylamine solvent. Upon heating from 140 °C to 180 °C, the solid sequentially transformed into two kinetically trapped FeS intermediate phases before reaching the pyrrhotite-4M final product. Finally, we assessed the effects of iron vacancies using the stoichiometric end-member, troilite, as a reference system. Density functional theory calculations show that iron vacancies in troilite shift the structure from hexagonal FeS to a monoclinic structure, similar to crystal structures of pyrrhotites, and suggest that this iron deficient troilite may be a stable intermediate between the two crystal structures. The calculations predict that defects also close the band gap in iron deficient troilite.
High throughput evaluation of macrocyclization strategies for conformer stabilization
Authors: Sindhikara Dan , Borrelli Ken 
Published: April 2018

AbstractWhile macrocyclization of a linear compound to stabilize a known bioactive conformation can be a useful strategy to increase binding potency, the difficulty of macrocycle synthesis can limit the throughput of such strategies. Thus computational techniques may offer the higher throughput required to screen large numbers of compounds. Here we introduce a method for evaluating the propensity of a macrocyclic compound to adopt a conformation similar that of a known active linear compound in the binding site. This method can be used as a fast screening tool for prioritizing macrocycles by leveraging the assumption that the propensity for the known bioactive substructural conformation relates to the affinity. While this method cannot to identify new interactions not present in the known linear compound, it could quickly differentiate compounds where the three dimensional geometries imposed by the macrocyclization prevent adoption of conformations with the same contacts as the linear compound in their conserved region. Here we report the implementation of this method using an RMSD-based structural descriptor and a Boltzmann-weighted propensity calculation and apply it retrospectively to three macrocycle linker optimization design projects. We found the method performs well in terms of prioritizing more potent compounds.
3D Reconstruction of Lipid Droplets in the Seed of Brassica napus
Authors: Yin Yongtai , Guo Liangxing , Chen Kang , Guo Zhenyi , Chao Hongbo , Wang Baoshan , Li Maoteng 
Published: April 2018

AbstractRapeseed is one of the most important and widely cultured oilseed crops for food and nonfood purposes worldwide. Neutral lipids are stored in lipid droplets (LDs) as fuel for germination and subsequent seedling growth. Most of the LD detection in seeds was still in 2D levels, and some of the details might have been lost in previous studies. In the present work, the configuration of LDs in seeds was obtained by confocal imaging combined with 3D reconstruction technology in Brassica napus. The size and shape of LDs, LD numbers, cell interval spaces and cell size were observed and compared at 3D levels in the seeds of different materials with high and low oil content. It was also revealed that different cells located in the same tissue exhibited various oil contents according to the construction at the 3D level, which was not previously reported in B. napus. The present work provides a new way to understand the differential in cell populations and enhance the seed oil content at the single cell level within seeds.
Transient elevation of cytoplasmic calcium ion concentration at a single cell level precedes morphological changes of epidermal keratinocytes during cornification
Authors: Murata Teruasa , Honda Tetsuya , Egawa Gyohei , Yamamoto Yasuo , Ichijo Ryo , Toyoshima Fumiko , Dainichi Teruki , Kabashima Kenji 
Published: April 2018

AbstractEpidermal keratinocytes achieve sequential differentiation from basal to granular layers, and undergo a specific programmed cell death, cornification, to form an indispensable barrier of the body. Although elevation of the cytoplasmic calcium ion concentration ([Ca2+]i) is one of the factors predicted to regulate cornification, the dynamics of [Ca2+]i in epidermal keratinocytes is largely unknown. Here using intravital imaging, we captured the dynamics of [Ca2+]i in mouse skin. [Ca2+]i was elevated in basal cells on the second time scale in three spatiotemporally distinct patterns. The transient elevation of [Ca2+]i also occurred at the most apical granular layer at a single cell level, and lasted for approximately 40 min. The transient elevation of [Ca2+]i at the granular layer was followed by cornification, which was completed within 10 min. This study demonstrates the tightly regulated elevation of [Ca2+]i preceding the cornification of epidermal keratinocytes, providing possible clues to the mechanisms of cornification.
JIB-04, A Small Molecule Histone Demethylase Inhibitor, Selectively Targets Colorectal Cancer Stem Cells by Inhibiting the Wnt/β-Catenin Signaling Pathway
Authors: Kim Min Seong , Cho Hye In , Yoon Hee Jung , Ahn Ye-Hyeon , Park Eun Jung , Jin Yan Hua , Jang Yeun Kyu 
Published: April 2018

AbstractAlthough several epigenetic modulating drugs are suggested to target cancer stem cells (CSCs), additional identification of anti-CSC drugs is still necessary. Here we showed that JIB-04, a pan-selective inhibitor of histone demethylase(s), was identified as a small molecule that selectively target colorectal CSCs. Our data showed that JIB-04 is capable of reducing self-renewal and stemness of colorectal CSCs in three different colorectal cancer cell lines. JIB-04 significantly attenuated CSC tumorsphere formation, growth/relapse, invasion, and migration in vitro. Furthermore, JIB-04-treated colorectal cancer cells showed reduced tumorigenic activity in vivo. RNA sequencing analysis revealed that JIB-04 affected various cancer-related signaling pathways, especially Wnt/β-catenin signaling, which is crucial for the proliferation and maintenance of colorectal cancer cells. qRT-PCR and TOP/FOP flash luciferase assays showed that JIB-04 down-regulated the expression of Wnt/β-catenin-regulated target genes associated with colorectal CSC function. Overall, the effects of JIB-04 were equal to or greater than those of salinomycin, a known anti-colorectal CSC drug, despite the lower concentration of JIB-04 compared with that of salinomycin. Our results strongly suggest that JIB-04 is a promising drug candidate for colorectal cancer therapy.
Endometrial Mesenchymal Stem/Stromal Cells Modulate the Macrophage Response to Implanted Polyamide/Gelatin Composite Mesh in Immunocompromised and Immunocompetent Mice
Authors: Darzi S. , Deane J. A. , Nold C. A. , Edwards S. E. , Gough D. J. , Mukherjee S. , Gurung S. , Tan K. S. , Vashi A. V. , Werkmeister J. A. , Gargett C. E. 
Published: April 2018

AbstractThe immunomodulatory properties of human endometrial mesenchymal stem cells (eMSC) have not been well characterised. Initial studies showed that eMSC modulated the chronic inflammatory response to a non-degradable polyamide/gelatin mesh in a xenogeneic rat skin wound repair model, but the mechanism remains unclear. In this study, we investigated the immunomodulatory effect of eMSC on the macrophage response to polyamide/gelatin composite mesh in an abdominal subcutaneous wound repair model in C57BL6 immunocompetent and NSG (NOD-Scid-IL2Rgamma
null
) immunocompromised mice to determine whether responses differed in the absence of an adaptive immune system and NK cells. mCherry lentivirus-labelled eMSC persisted longer in NSG mice, inducing longer term paracrine effects. Inclusion of eMSC in the mesh reduced inflammatory cytokine (Il-1β, Tnfα) secretion, and in C57BL6 mice reduced CCR7+ M1 macrophages surrounding the mesh on day 3 and increased M2 macrophage marker mRNA (Arg1, Mrc1, Il10) expression at days 3 and 7. In NSG mice, these effects were delayed and only observed at days 7 and 30 in comparison with controls implanted with mesh alone. These results show that the differences in the immune status in the two animals directly affect the survival of xenogeneic eMSC which leads to differences in the short-term and long-term macrophage responses to implanted meshes.
Analysis of natural female post-mating responses of Anopheles gambiae and Anopheles coluzzii unravels similarities and differences in their reproductive ecology
Authors: Thailayil Janis , Gabrieli Paolo , Caputo Beniamino , Bascuñán Priscila , South Adam , Diabate Abdoulaye , Dabire Roch , della Torre Alessandra , Catteruccia Flaminia 
Published: April 2018

AbstractAnopheles gambiae and An. coluzzii, the two most important malaria vectors in sub-Saharan Africa, are recently radiated sibling species that are reproductively isolated even in areas of sympatry. In females from these species, sexual transfer of male accessory gland products, including the steroid hormone 20-hydroxyecdysone (20E), induces vast behavioral, physiological, and transcriptional changes that profoundly shape their post-mating ecology, and that may have contributed to the insurgence of post-mating, prezygotic reproductive barriers. As these barriers can be detected by studying transcriptional changes induced by mating, we set out to analyze the post-mating response of An. gambiae and An. coluzzii females captured in natural mating swarms in Burkina Faso. While the molecular pathways shaping short- and long-term mating-induced changes are largely conserved in females from the two species, we unravel significant inter-specific differences that suggest divergent regulation of key reproductive processes such as egg development, processing of seminal secretion, and mating behavior, that may have played a role in reproductive isolation. Interestingly, a number of these changes occur in genes previously shown to be regulated by the sexual transfer of 20E and may be due to divergent utilization of this steroid hormone in the two species.
Synthesis and conformational analysis of linear homo- and heterooligomers from novel 2-C-branched sugar amino acids (SAAs)
Authors: Tian Guang-Zong , Hu Jing , Zhang Heng-Xi , Rademacher Christoph , Zou Xiao-Peng , Zheng Hong-Ning , Xu Fei , Wang Xiao-Li , Linker Torsten , Yin Jian 
Published: April 2018

AbstractSugar amino acids (SAAs), as biologically interesting structures bearing both amino and carboxylic acid functional groups represent an important class of multifunctional building blocks. In this study, we develop an easy access to novel SAAs in only three steps starting from nitro compounds in high yields in analytically pure form, easily available by ceric (IV) mediated radical additions. Such novel SAAs have been applied in the assembly of total nine carbopeptoids with the form of linear homo- and heterooligomers for the structural investigations employing circular dichroism (CD) spectroscopy, which suggest that the carbopeptoids emerge a well-extended, left (or right)-handed conformation similar to polyproline II (PPII) helices. NMR studies also clearly demonstrated the presence of ordered secondary structural elements. 2D-ROESY spectra were acquired to identify
i+1
NH ↔
i
C
1
H,
i
C
2
H correlations which support the conformational analysis of tetramers by CD spectroscopy. These findings provide interesting information of SAAs and their oligomers as potential scaffolds for discovering new drugs and materials.
A closer look at cross-validation for assessing the accuracy of gene regulatory networks and models
Authors: Tabe-Bordbar Shayan , Emad Amin , Zhao Sihai Dave , Sinha Saurabh 
Published: April 2018

AbstractCross-validation (CV) is a technique to assess the generalizability of a model to unseen data. This technique relies on assumptions that may not be satisfied when studying genomics datasets. For example, random CV (RCV) assumes that a randomly selected set of samples, the test set, well represents unseen data. This assumption doesn’t hold true where samples are obtained from different experimental conditions, and the goal is to learn regulatory relationships among the genes that generalize beyond the observed conditions. In this study, we investigated how the CV procedure affects the assessment of supervised learning methods used to learn gene regulatory networks (or in other applications). We compared the performance of a regression-based method for gene expression prediction estimated using RCV with that estimated using a clustering-based CV (CCV) procedure. Our analysis illustrates that RCV can produce over-optimistic estimates of the model’s generalizability compared to CCV. Next, we defined the ‘distinctness’ of test set from training set and showed that this measure is predictive of performance of the regression method. Finally, we introduced a simulated annealing method to construct partitions with gradually increasing distinctness and showed that performance of different gene expression prediction methods can be better evaluated using this method.
Premyogenic progenitors derived from human pluripotent stem cells expand in floating culture and differentiate into transplantable myogenic progenitors
Authors: Sakai-Takemura Fusako , Narita Asako , Masuda Satoru , Wakamatsu Toshifumi , Watanabe Nobuharu , Nishiyama Takashi , Nogami Ken’ichiro , Blanc Matthias , Takeda Shin’ichi , Miyagoe-Suzuki Yuko 
Published: April 2018

AbstractHuman induced pluripotent stem cells (hiPSCs) are a potential source for cell therapy of Duchenne muscular dystrophy. To reliably obtain skeletal muscle progenitors from hiPSCs, we treated hiPS cells with a Wnt activator, CHIR-99021 and a BMP receptor inhibitor, LDN-193189, and then induced skeletal muscle cells using a previously reported sphere-based culture. This protocol greatly improved sphere formation efficiency and stably induced the differentiation of myogenic cells from hiPS cells generated from both healthy donors and a patient with congenital myasthenic syndrome. hiPSC-derived myogenic progenitors were enriched in the CD57(−) CD108(−) CD271(+) ERBB3(+) cell fraction, and their differentiation was greatly promoted by TGF-β inhibitors. TGF-β inhibitors down-regulated the NFIX transcription factor, and NFIX short hairpin RNA (shRNA) improved the differentiation of iPS cell-derived myogenic progenitors. These results suggest that NFIX inhibited differentiation of myogenic progenitors. hiPSC-derived myogenic cells differentiated into myofibers in muscles of NSG-mdx
4Cv
mice after direct transplantation. Our results indicate that our new muscle induction protocol is useful for cell therapy of muscular dystrophies.
Dissociating the effect of disruptive colouration on localisation and identification of camouflaged targets
Authors: Sharman Rebecca J. , Moncrieff Stephen J. , Lovell P. George 
Published: April 2018

AbstractDisruptive camouflage features contrasting areas of pigmentation across the animals’ surface that form false edges which disguise the shape of the body and impede detection. In many taxa these false edges feature local contrast enhancement or edge enhancement, light areas have lighter edges and dark areas have darker edges. This additional quality is often overlooked in existing research. Here we ask whether disruptive camouflage can have benefits above and beyond concealing location. Using a novel paradigm, we dissociate the time courses of localisation and identification of a target in a single experiment. We measured the display times required for a stimulus to be located or identified (the critical duration). Targets featured either uniform, disruptive or edge enhanced disruptive colouration. Critical durations were longer for identifying targets with edge enhanced disruptive colouration camouflage even when presented against a contrasting background, such that all target types were located equally quickly. For the first time, we establish empirically that disruptive camouflage not only conceals location, but also disguises identity. This shows that this form of camouflage can be useful even when animals are not hidden. Our findings offer insights into how edge enhanced disruptive colouration undermines visual perception by disrupting object recognition.
Local Moment Instability of Os in Honeycomb Li2.15Os0.85O3
Authors: Wallace M. K. , LaBarre P. G. , Li Jun , Pi S.-T. , Pickett W. E. , Dessau D. S. , Haskel D. , Ramirez A. P. , Subramanian M. A. 
Published: April 2018

AbstractCompounds with honeycomb structures occupied by strong spin orbit coupled (SOC) moments are considered to be candidate Kitaev quantum spin liquids. Here we present the first example of Os on a honeycomb structure, Li2.15(3)Os0.85(3)O3 (C2/c, a = 5.09 Å, b = 8.81 Å, c = 9.83 Å, β = 99.3°). Neutron diffraction shows large site disorder in the honeycomb layer and X-ray absorption spectroscopy indicates a valence state of Os (4.7 ± 0.2), consistent with the nominal concentration. We observe a transport band gap of Δ = 243 ± 23 meV, a large van Vleck susceptibility, and an effective moment of 0.85 μB, much lower than expected from 70% Os(+5). No evidence of long range order is found above 0.10 K but a spin glass-like peak in ac-susceptibility is observed at 0.5 K. The specific heat displays an impurity spin contribution in addition to a power law ∝T(0.63±0.06). Applied density functional theory (DFT) leads to a reduced moment, suggesting incipient itineracy of the valence electrons, and finding evidence that Li over stoichiometry leads to Os(4+)−Os(5+) mixed valence. This local picture is discussed in light of the site disorder and a possible underlying quantum spin liquid state.
The origin, type and hydrocarbon generation potential of organic matter in a marine-continental transitional facies shale succession (Qaidam Basin, China)
Authors: Wang Guo-Cang , Sun Min-Zhuo , Gao Shu-Fang , Tang Li 
Published: April 2018

AbstractThis organic-rich shale was analyzed to determine the type, origin, maturity and depositional environment of the organic matter and to evaluate the hydrocarbon generation potential of the shale. This study is based on geochemical (total carbon content, Rock-Eval pyrolysis and the molecular composition of hydrocarbons) and whole-rock petrographic (maceral composition) analyses. The petrographic analyses show that the shale penetrated by the Chaiye 2 well contains large amounts of vitrinite and sapropelinite and that the organic matter within these rocks is type III and highly mature. The geochemical analyses show that these rocks are characterized by high total organic carbon contents and that the organic matter is derived from a mix of terrestrial and marine sources and highly mature. These geochemical characteristics are consistent with the results of the petrographic analyses. The large amounts of organic matter in the Carboniferous shale succession penetrated by the Chaiye 2 well may be due to good preservation under hypersaline lacustrine and anoxic marine conditions. Consequently, the studied shale possesses very good hydrocarbon generation potential because of the presence of large amounts of highly mature type III organic matter.
Day length is associated with physical activity and sedentary behavior among older women
Authors: Schepps Mitchell A. , Shiroma Eric J. , Kamada Masamitsu , Harris Tamara B. , Lee I-Min 
Published: April 2018

AbstractPhysical activity may be influenced by one’s physical environment, including day length and weather. Studies of physical activity, day length, and weather have primarily used self-reported activity, broad meteorological categorization, and limited geographic regions. We aim to examine the association of day length and physical activity in a large cohort of older women, covering a wide geographic range. Participants (N = 16,741; mean (SD) age = 72.0 (SD = 5.7) years) were drawn from the Women’s Health Study and lived throughout the United States. Physical activity was assessed by accelerometer (ActiGraph GT3X+) between 2011 and 2015. Day length and weather information were obtained by matching weather stations to the participants’ location using National Oceanic and Atmospheric Administration databases. Women who experienced day lengths greater than 14 hours had 5.5% more steps, 9.4% more moderate-to-vigorous physical activity, and 1.6% less sedentary behavior, compared to women who experienced day lengths less than 10 hours, after adjusting for age, accelerometer wear, temperature, and precipitation. Day length is associated with physical activity and sedentary behavior in older women, and needs to be considered in programs promoting physical activity as well as in the analyses of accelerometer data covering wide geographic regions.
Miniaturised printed monopole antenna with a linked ground plane and radiator
Authors: Ellis M.S. , Ahmed A.‐R. , Kponyo J.J. , Nourinia J. , Gbobadi Ch. , Mohammadi B. 
Published: April 2018

A novel miniature wideband microstrip antenna is presented. The proposed miniature design is achieved by exploiting the idea of a quasi‐radiator. Here, a part of the radiator is connected to the ground plane through a shorting pin or via. The proposed antenna achieves a starting frequency of 1.8 GHz with a small antenna area of 20 mm2. An electrical size of 0.05λ is realised leading to a miniaturised design. The proposed antenna is broadband, compact, and produces stable radiation patterns.
Ceramic-on-Polyethylene Bearing Usage in Primary THA Is Associated with Reduced Readmission Risk for the Medicare Population
Authors: Lau Edmund , Baykal Doruk , Springer Bryan , Kurtz Steven 
Published: April 2018

AbstractThe authors hypothesized that unplanned readmissions, which are often caused by infections and dislocation, may be reduced with ceramic bearing usage. They also sought to confirm that the readmission rates for ceramic bearings were associated with the year of surgery. They identified 245,077 elderly patients (65+) who underwent primary total hip arthroplasty (THA) between 2010 and 2015 with known bearing types (ceramic-on-polyethylene [C-PE] ceramic-on-ceramic [COC], and metal-on-polyethylene [M-PE]) from the Medicare 100% inpatient database. Outcomes included relative risk of 30- and 90-day readmission. Propensity scores were developed to adjust for selection bias in the choice of bearing type at index surgery. Cox regression incorporating propensity score stratification (10 levels) was used to evaluate the impact of bearing selection on outcomes, after adjusting for patient-, hospital-, surgeon-related factors, as well as the year of surgery. With C-PE bearings, the unadjusted (crude) 90-day readmission rate decreased from 8.7% in 2010 to 8.3% in 2015. For COC bearings, the crude 90-day readmission rate decreased from 10.5 to 9.1% from 2010 to 2015. After adjustment, year of surgery was associated with reduced readmission risk for both types of ceramic bearings in 30-day readmissions (p < 0.05) and COC in 90-day readmissions (p < 0.001). The authors also found that C-PE bearings were associated with significantly reduced readmission risk relative to M-PE at 30 days (hazard ratio [HR]: 0.91, p < 0.001) and 90 days (HR: 0.93, p < 0.001). In terms of strength of association with 90-day readmission, however, it was ranked the ninth most associated independent factor. To the authors' knowledge, this is the first study to demonstrate an association between THA implant characteristics (in this case C-PE bearing usage) and reduced readmission rates in this context along with patient- and clinical-related factors. The readmission rates for COC were found to be comparable to M-PE.