bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectral management and energy‐transfer mechanism of Eu3+‐doped β‐NaGdF4:Yb3+,Er3+ microcrystals
Authors: Yao Lu , Xu Dekang , Lin Hao , Li Anming , Yang Shenghong , Zhang Yueli 
Published: May 2017

Abstractβ‐NaGdF4:Yb3+,Er3+ upconversion (UC) microcrystals were prepared by a facile hydrothermal process with the assistance of ethylene diamine tertraacetic acid (EDTA). The β‐NaGdF4 UC microcrystal morphology was controlled by changing the doses of EDTA and NaF. Uniform hexagonal structure can be obtained at the 2 mmol EDTA and 9‐10 mmol NaF. The UC emissions of β‐NaGdF4:Yb3+,Er3+ microcrystals were tuned by the variation of Eu3+ doping level (0%‐5%), where the red/green intensity ratio decreased with the Eu3+ concentration increase. It was found on the base of rate equations that with the Eu3+ doping, the energy back transfer process 2H11/2/4S3/2 (Er3+) → 4I13/2 (Er3+) decreased. In addition, an energy‐transfer process from 4F7/2 (Er3+) to 5D1 (Eu3+) and a cross relaxation process of 7H9/2 (Er3+) + 5D0 (Eu3+) → 4F7/2 (Er3+) + 5D2 (Eu3+) were proposed and verified by rate equations, which dominated the energy‐transfer mechanism between Er3+ and Eu3+, resulted in the spectra tuning of β‐NaGdF4:Yb3+,Er3+. The results suggested that the color tuning of β‐NaGdF4:Yb3+,Er3+,Eu3+ UC microcrystals would have potential applications in such fields as flat‐panel displays, solid‐state lasers, and photovoltaics.
An Explanatory Model of Dating Violence Risk Factors in Spanish Adolescents
Authors: Aizpitarte Alazne , Alonso‐Arbiol Itziar , Van de Vijver Fons J. R. 
Published: May 2017

Dating violence is a serious public health issue that needs further understanding in terms of risk factors that may be involved in it. The main goal of this study was to test a mediational model of dating violence risk factors. The sample was composed of 477 secondary and college students from Spain (59% females). A dynamic developmental explanatory model considering aggressiveness, insecure attachment, interparental conflict, and peer dating violence was tested using a multigroup structural equation model. Aggressiveness partially mediated the relation between anxious attachment and dating violence and fully mediated the association between interparental conflict resolution and dating violence. Furthermore, perceived peer dating violence was a direct predictor of dating violence. Implications for prevention and intervention plans are discussed.
Melatonin ameliorates myocardial ischemia reperfusion injury through SIRT3‐dependent regulation of oxidative stress and apoptosis
Authors: Zhai Mengen , Li Buying , Duan Weixun , Jing Lin , Zhang Bin , Zhang Meng , Yu Liming , Liu Zhenhua , Yu Bo , Ren Kai , Gao Erhe , Yang Yang , Liang Hongliang , Jin Zhenxiao , Yu Shiqiang 
Published: May 2017

AbstractSirtuins are a family of highly evolutionarily conserved nicotinamide adenine nucleotide‐dependent histone deacetylases. Sirtuin‐3 (SIRT3) is a member of the sirtuin family that is localized primarily to the mitochondria and protects against oxidative stress‐related diseases, including myocardial ischemia/reperfusion (MI/R) injury. Melatonin has a favorable effect in ameliorating MI/R injury. We hypothesized that melatonin protects against MI/R injury by activating the SIRT3 signaling pathway. In this study, mice were pretreated with or without a selective SIRT3 inhibitor and then subjected to MI/R operation. Melatonin was administered intraperitoneally (20 mg/kg) 10 minutes before reperfusion. Melatonin treatment improved postischemic cardiac contractile function, decreased infarct size, diminished lactate dehydrogenase release, reduced the apoptotic index, and ameliorated oxidative damage. Notably, MI/R induced a significant decrease in myocardial SIRT3 expression and activity, whereas the melatonin treatment upregulated SIRT3 expression and activity, and thus decreased the acetylation of superoxide dismutase 2 (SOD2). In addition, melatonin increased Bcl‐2 expression and decreased Bax, Caspase‐3, and cleaved Caspase‐3 levels in response to MI/R. However, the cardioprotective effects of melatonin were largely abolished by the selective SIRT3 inhibitor 3‐(1H‐1,2,3‐triazol‐4‐yl)pyridine (3‐TYP), suggesting that SIRT3 plays an essential role in mediating the cardioprotective effects of melatonin. In vitro studies confirmed that melatonin also protected H9c2 cells against simulated ischemia/reperfusion injury (SIR) by attenuating oxidative stress and apoptosis, while SIRT3‐targeted siRNA diminished these effects. Taken together, our results demonstrate for the first time that melatonin treatment ameliorates MI/R injury by reducing oxidative stress and apoptosis via activating the SIRT3 signaling pathway.
The role of melatonin in the neurodevelopmental etiology of schizophrenia: A study in human olfactory neuronal precursors
Authors: Galván‐Arrieta Tania , Trueta Citlali , Cercós Montserrat G. , Valdés‐Tovar Marcela , Alarcón Salvador , Oikawa Julian , Zamudio‐Meza Horacio , Benítez‐King Gloria 
Published: May 2017

AbstractDim light exposure of the mother during pregnancy has been proposed as one of the environmental factors that affect the fetal brain development in schizophrenia. Melatonin circulating levels are regulated by the environmental light/dark cycle. This hormone stimulates neuronal differentiation in the adult brain. However, little is known about its role in the fetal human brain development. Olfactory neuronal precursors (ONPs) are useful for studying the physiopathology of neuropsychiatric diseases because they mimic all the stages of neurodevelopment in culture. Here, we first characterized whether melatonin stimulates neuronal differentiation in cloned ONPs obtained from a healthy control subject (HCS). Then, melatonin effects were evaluated in primary cultures of ONPs derived from a patient diagnosed with schizophrenia (SZ) and an age‐ and gender‐matched HCS. Axonal formation was evidenced morphologically by tau immunostaining and by GSK3β phosphorylated state. Potassium‐evoked secretion was assessed as a functional feature of differentiated neurons. As well, we report the expression of MT1/2 receptors in human ONPs for the first time. Melatonin stimulated axonal formation and ramification in cloned ONPs through a receptor‐mediated mechanism and enhanced the amount and velocity of axonal and somatic secretion. SZ ONPs displayed reduced axogenesis associated with lower levels of pGSK3β and less expression of melatonergic receptors regarding the HCS ONPs. Melatonin counteracted this reduction in SZ cells. Altogether, our results show that melatonin signaling is crucial for functional differentiation of human ONPs, strongly suggesting that a deficit of this indoleamine may lead to an impaired neurodevelopment which has been associated with the etiology of schizophrenia.
Melatonin protects bone marrow mesenchymal stem cells against iron overload‐induced aberrant differentiation and senescence
Authors: Yang Fan , Yang Lei , Li Yuan , Yan Gege , Feng Chao , Liu Tianyi , Gong Rui , Yuan Ye , Wang Ning , Idiiatullina Elina , Bikkuzin Timur , Pavlov Valentin , Li Yang , Dong Chaorun , Wang Dawei , Cao Yang , Han Zhenbo , Zhang Lai , Huang Qi , Ding Fengzhi , Bi Zhengang , Cai Benzhi 
Published: May 2017

AbstractBone marrow mesenchymal stem cells (BMSCs) are an expandable population of stem cells which can differentiate into osteoblasts, chondrocytes and adipocytes. Dysfunction of BMSCs in response to pathological stimuli contributes to bone diseases. Melatonin, a hormone secreted from pineal gland, has been proved to be an important mediator in bone formation and mineralization. The aim of this study was to investigate whether melatonin protected against iron overload‐induced dysfunction of BMSCs and its underlying mechanisms. Here, we found that iron overload induced by ferric ammonium citrate (FAC) caused irregularly morphological changes and markedly reduced the viability in BMSCs. Consistently, osteogenic differentiation of BMSCs was significantly inhibited by iron overload, but melatonin treatment rescued osteogenic differentiation of BMSCs. Furthermore, exposure to FAC led to the senescence in BMSCs, which was attenuated by melatonin as well. Meanwhile, melatonin was able to counter the reduction in cell proliferation by iron overload in BMSCs. In addition, protective effects of melatonin on iron overload‐induced dysfunction of BMSCs were abolished by its inhibitor luzindole. Also, melatonin protected BMSCs against iron overload‐induced ROS accumulation and membrane potential depolarization. Further study uncovered that melatonin inhibited the upregulation of p53, ERK and p38 protein expressions in BMSCs with iron overload. Collectively, melatonin plays a protective role in iron overload‐induced osteogenic differentiation dysfunction and senescence through blocking ROS accumulation and p53/ERK/p38 activation.
Exploring the value of mental health nurses working in primary care in England: A qualitative study
Authors: McLeod K. , Simpson A. 
Published: May 2017

Accessible SummaryWhat is known on the subject?

Primary care and, in particular, general practice (GP) are often first point of access to health care. International evidence suggests that healthcare systems oriented towards primary care may produce better outcomes, at lower costs and with higher user satisfaction. Despite this, there are noted deficiencies and variations in the quality of care in primary care for patients with mental health problems.

What this paper adds to existing knowledge?

Emerging models of providing mental health services in primary care are poorly understood. This paper evaluates a mental health nurse‐led Primary Care Liaison Service (PCLS), developed in 2011 in inner London.

The findings suggest that this type of service can improve the quality of care for people presenting with mental health problems within primary care, specifically due to improved integration, clinical effectiveness, patient‐centred care, access and efficiency. The study also highlighted challenges such as staff retention within this new role and setting appropriate referral criteria.

What are the implications for practice?

This is a relatively new service, and the cost‐effectiveness is not yet fully understood; however, commissioners may want to consider the potential benefits of a similar service in their area. The extent to which the findings are transferable will depend on service configuration and local demographics which can vary.

Further research within this area could give more detail on the impact of such teams on health outcomes, recovery rates, secondary care referrals and accident and emergency attendances, and its cost‐effectiveness.

AbstractAims/QuestionGeneral practice is typically the first point of access to healthcare. This study explores what value a Primary Care Liaison Nurse (PCLN) service, established in 2011, can bring to people with mental health problems in primary care.MethodSemi‐structured interviews were used to elicit participants’ experiences and perspectives on the value of a PCLN service. Participants included ten interviews with seven general practitioners and three senior practitioners working in primary care mental health services. Thematic analysis, based on a 6‐phase approach, was used to describe and explore the data collected.ResultsFive main themes were derived from the thematic analysis of the interviews relating to: integration; clinical effectiveness; patient centred care; access; and efficiency.DiscussionThe study suggests that the PCLN service can improve the quality of care and is generally highly valued by its stakeholders. The study identifies particularly valued elements of the service, including having a duty worker, as well as aspects which could be improved, such as patient criteria.Implications for practiceThis is a relatively new service and the cost‐effectiveness is not yet fully understood; however, commissioners may want to consider the potential benefits of a similar service in their area.
The transcriptional landscape of seasonal coat colour moult in the snowshoe hare
Authors: Ferreira Mafalda S. , Alves Paulo C. , Callahan Colin M. , Marques João P. , Mills L. Scott , Good Jeffrey M. , Melo‐Ferreira José 
Published: May 2017

AbstractSeasonal coat colour change is an important adaptation to seasonally changing environments but the evolution of this and other circannual traits remains poorly understood. In this study, we use gene expression to understand seasonal coat colour moulting in wild snowshoe hares (Lepus americanus). We used hair colour to follow the progression of the moult, simultaneously sampling skin from three moulting stages in hares collected during the peak of the spring moult from white winter to brown summer pelage. Using RNA sequencing, we tested whether patterns of expression were consistent with predictions based on the established phases of the hair growth cycle. We found functionally consistent clustering across skin types, with 766 genes differentially expressed between moult stages. “White” pelage showed more differentially expressed genes that were upregulated relative to other skin types, involved in the transition between late telogen (quiescent stage) and the onset of anagen (proliferative stage). Skin samples from transitional “intermediate” and “brown” pelage were transcriptionally similar and resembled the regressive transition to catagen (regressive stage). We also detected differential expression of several key circadian clock and pigmentation genes, providing important means to dissect the bases of alternate seasonal colour morphs. Our results reveal that pelage colour is a useful biomarker for seasonal change but that there is a consistent lag between the main gene expression waves and change in visible coat colour. These experiments establish that developmental sampling from natural populations of nonmodel organisms can provide a crucial resource to dissect the genetic basis and evolution of complex seasonally changing traits.
Efficiency Gains in Rank‐ordered Multinomial Logit Models
Authors: Beresteanu Arie , Zincenko Federico 
Published: May 2017

AbstractThis paper considers estimation of discrete choice models when agents report their ranking of the alternatives (or some of them) rather than just the utility maximizing alternative. We investigate the parametric conditional rank‐ordered Logit model. We show that conditions for identification do not change even if we observe ranking. Moreover, we fill a gap in the literature and show analytically and by Monte Carlo simulations that efficiency increases as we use additional information on the ranking.
High‐density genotyping of the A.E. Watkins Collection of hexaploid landraces identifies a large molecular diversity compared to elite bread wheat
Authors: Winfield Mark O. , Allen Alexandra M. , Wilkinson Paul A. , Burridge Amanda J. , Barker Gary L.A. , Coghill Jane , Waterfall Christy , Wingen Luzie U. , Griffiths Simon , Edwards Keith J. 
Published: May 2017

SummaryThe importance of wheat as a food crop makes it a major target for agricultural improvements. As one of the most widely grown cereal grains, together with maize and rice, wheat is the leading provider of calories in the global diet, constituting 29% of global cereal production in 2015. In the last few decades, however, yields have plateaued, suggesting that the green revolution, at least for wheat, might have run its course and that new sources of genetic variation are urgently required. The overall aim of our work was to identify novel variation that may then be used to enable the breeding process. As landraces are a potential source of such diversity, here we have characterized the A.E. Watkins Collection alongside a collection of elite accessions using two complementary high‐density and high‐throughput genotyping platforms. While our results show the importance of using the appropriate SNP collection to compare diverse accessions, they also show that the Watkins Collection contains a substantial amount of novel genetic diversity which has either not been captured in current breeding programmes or which has been lost through previous selection pressures. As a consequence of our analysis, we have identified a number of accessions which carry an array of novel alleles along with a number of interesting chromosome rearrangements which confirm the variable nature of the wheat genome.
Distinctive Properties of Dark Reversion Kinetics between Two Red/Green‐Type Cyanobacteriochromes and their Application in the Photoregulation of cAMP Synthesis
Authors: Fushimi Keiji , Enomoto Gen , Ikeuchi Masahiko , Narikawa Rei 
Published: May 2017

AbstractCyanobacteriochromes (CBCRs) are photoreceptors that bind to a linear tetrapyrrole within a conserved cGMP‐phosphodiesterase/adenylate cyclase/FhlA (GAF) domain and exhibit reversible photoconversion. Red/green‐type CBCR GAF domains that photoconvert between red‐ (Pr) and green‐absorbing (Pg) forms occur widely in various cyanobacteria. A putative phototaxis regulator, AnPixJ, contains multiple red/green‐type CBCR GAF domains. We previously reported that AnPixJ's second domain (AnPixJg2) but not its fourth domain (AnPixJg4) shows red/green reversible photoconversion. Herein, we found that AnPixJg4 showed Pr‐to‐Pg photoconversion and rapid Pg‐to‐Pr dark reversion, whereas AnPixJg2 showed a barely detectable dark reversion. Site‐directed mutagenesis revealed the involvement of six residues in Pg stability. Replacement at the Leu294/Ile660 positions of AnPixJg2/AnPixJg4 showed the highest influence on dark reversion kinetics. AnPixJg2_DR6, wherein the six residues of AnPixJg2 were entirely replaced with those of AnPixJg4, showed a 300‐fold faster dark reversion than that of the wild type. We constructed chimeric proteins by fusing the GAF domains with adenylate cyclase catalytic regions, such as AnPixJg2‐AC, AnPixJg4‐AC and AnPixJg2_DR6‐AC. We detected successful enzymatic activation under red light for both AnPixJg2‐AC and AnPixJg2_DR6‐AC, and repression under green light for AnPixJg2‐AC and under dark incubation for AnPixJg2_DR6‐AC. These results provide platforms to develop cAMP synthetic optogenetic tools.
Crystal Effects on Mesobilirubin: A Combined NMR Spectroscopic and Density Functional Theory Study
Authors: Song Chen , Matysik Jörg , Mark Franz 
Published: May 2017

AbstractWe report solid‐state NMR investigations of crystal effects in powdered mesobilirubin‐IXα, an open‐chain tetrapyrrole that is structurally related to bilirubin‐IXα but hydrogenated at the 3‐ and 18‐vinyl groups. 13C and 15N cross‐polarization magic‐angle spinning (CP/MAS) NMR experiments were performed on the compound at natural abundance. To facilitate the spectral analysis, density functional calculations were carried out at the B3LYP/6‐311G(d,p) level of theory, using an enneameric cluster to simulate the solid. The 1H, 13C and 15N chemical shift data calculated for the enneamer are in a good agreement with those observed in the experimental spectra, and the relative order of the calculated resonances was thus used to confirm the tentative assignments obtained mainly from the heteronuclear correlation spectra. The observed signal splittings of a small subset of the 13C resonances in the peripheral regions of the two terminal rings provide evidence for microcrystalline heterogeneity of the powdered compound.
Structural and Vibrational Characterization of the Chromophore Binding Site of Bacterial Phytochrome Agp1
Authors: Takiden Aref , Velazquez‐Escobar Francisco , Dragelj Jovan , Woelke Anna Lena , Knapp Ernst‐Walter , Piwowarski Patrick , Bart Franz , Hildebrandt Peter , Mroginski Maria Andrea 
Published: May 2017

AbstractAgp1 is a prototypical bacterial phytochrome from Agrobacterium fabrum harboring a biliverdin cofactor which reversibly photoconverts between a red‐light‐absorbing (Pr) and a far‐red‐light‐absorbing (Pfr) states. The reaction mechanism involves the isomerization of the bilin‐chromophore followed by large structural changes of the protein matrix that are coupled to protonation dynamics at the chromophore binding site. Histidines His250 and His280 participate in this process. Although the three‐dimensional structure of Agp1 has been solved at high resolution, the precise position of hydrogen atoms and protonation pattern in the chromophore binding pocket has not been investigated yet. Here, we present protonated structure models of Agp1 in the Pr state involving appropriately placed hydrogen atoms that were generated by hybrid quantum mechanics/molecular mechanics‐ and electrostatic calculations and validated against experimental structural‐ and spectroscopic data. Although the effect of histidine protonation on the vibrational spectra is weak, our results favor charge neutral H250 and H280 both protonated at Nε. However, a neutral H250 with a proton at Nε and a cationic H280 may also be possible. Furthermore, the present QM/MM calculations of IR and Raman spectra of Agp1 containing isotope‐labeled BV provide a detailed vibrational assignment of the biliverdin modes in the fingerprint region.
Characterization of the Blue–Light‐Activated Adenylyl Cyclase mPAC by Flash Photolysis and FTIR Spectroscopy
Authors: Kerruth Silke , Langner Pit , Raffelberg Sarah , Gärtner Wolfgang , Heberle Joachim 
Published: May 2017

AbstractThe recently discovered photo‐activated adenylyl cyclase (mPAC from Microcoleus chthonoplastes) is the first PAC that owes a light‐, oxygen‐ and voltage‐sensitive (LOV) domain for blue‐light sensing. The photoreaction of the mPAC receptor was studied by time‐resolved UV/vis and light‐induced Fourier transform infrared (FTIR) absorption difference spectroscopy. The photocycle comprises of the typical triplet state LOV715 and the thio‐adduct state LOV390. While the adduct state decays with a time constant of 8 s, the lifetime of the triplet state is with 656 ns significantly shorter than in all other reported LOV domains. The light‐induced FTIR difference spectrum shows the typical bands of the LOV390 and LOV450 intermediates. The negative S‐H stretching vibration at 2573 cm−1 is asymmetric suggesting two rotamer configurations of the protonated side chain of C194. A positive band at 3632 cm−1 is observed, which is assigned to an internal water molecule. In contrast to other LOV domains, mPAC exhibits a second positive feature at 3674 cm−1 which is due to the O‐H stretch of a second intrinsic water molecule and the side chain of Y476. We conclude that the latter might be involved in the dimerization of the cyclase domain which is crucial for ATP binding.
Light‐Induced Conformational Changes in the Plant Cryptochrome Photolyase Homology Region Resolved by Selective Isotope Labeling and Infrared Spectroscopy
Authors: Sommer Constanze , Dietz Marina S. , Patschkowski Thomas , Mathes Tilo , Kottke Tilman 
Published: May 2017

AbstractPlant cryptochromes are photoreceptors that regulate flowering, circadian rhythm and photomorphogenesis in response to blue and UV‐A light. It has been demonstrated that the oxidized flavin cofactor is photoreduced to the neutral radical state via separate electron and proton transfer. Conformational changes have been found in the C‐terminal extension, but few studies have addressed the changes in secondary structure in the sensory photolyase homology region (PHR). Here, we investigated the PHR of the plant cryptochrome from the green alga Chlamydomonas reinhardtii by light‐induced infrared difference spectroscopy in combination with global 13C and 15N isotope labeling. Assignment of the signals is achieved by establishing a labeling strategy for cryptochromes that preserves the flavin at natural abundance. We demonstrate by UV/vis spectroscopy that the integrity of the sample is maintained and by mass spectrometry that the global labeling was highly efficient. As a result, difference bands are resolved at full intensity that at natural abundance are compensated by the overlap of flavin and protein signals. These bands are assigned to prominent conformational changes in the PHR by blue light illumination. We postulate that not only the partial unfolding of the C‐terminal extension but also changes in the PHR may mediate signaling events.