bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generation of gas‐phase ions from charged clusters: an important ionization step causing suppression of matrix and analyte ions in matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Lou Xianwen , van Dongen Joost L.J. , Milroy Lech‐Gustav , Meijer E.W. 
Published: September 2016

RationaleIonization in matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) is a very complicated process. It has been reported that quaternary ammonium salts show extremely strong matrix and analyte suppression effects which cannot satisfactorily be explained by charge transfer reactions. Further investigation of the reasons causing these effects can be useful to improve our understanding of the MALDI process.MethodsThe dried‐droplet and modified thin‐layer methods were used as sample preparation methods. In the dried‐droplet method, analytes were co‐crystallized with matrix, whereas in the modified thin‐layer method analytes were deposited on the surface of matrix crystals. Model compounds, tetrabutylammonium iodide ([N(Bu)4]I), cesium iodide (CsI), trihexylamine (THA) and polyethylene glycol 600 (PEG 600), were selected as the test analytes given their ability to generate exclusively pre‐formed ions, protonated ions and metal ion adducts respectively in MALDI.ResultsThe strong matrix suppression effect (MSE) observed using the dried‐droplet method might disappear using the modified thin‐layer method, which suggests that the incorporation of analytes in matrix crystals contributes to the MSE. By depositing analytes on the matrix surface instead of incorporating in the matrix crystals, the competition for evaporation/ionization from charged matrix/analyte clusters could be weakened resulting in reduced MSE. Further supporting evidence for this inference was found by studying the analyte suppression effect using the same two sample deposition methods.ConclusionsBy comparing differences between the mass spectra obtained via the two sample preparation methods, we present evidence suggesting that the generation of gas‐phase ions from charged matrix/analyte clusters may induce significant suppression of matrix and analyte ions. The results suggest that the generation of gas‐phase ions from charged matrix/analyte clusters is an important ionization step in MALDI‐MS. Copyright © 2016 John Wiley & Sons, Ltd.
Development and Evaluation of Different Methods for Preparation of Fluorine‐Containing (R)‐ and (S)‐N‐tert‐Butanesulfinyl–aldimines
Authors: Xie Chen , Zhang Lijun , Mei Haibo , Han Jianlin , Soloshonok Vadim A. , Pan Yi 
Published: September 2016

AbstractThis work is solely focused on the development of optimized procedures for preparation of various (S)‐N‐tert‐butanesulfinyl‐aldimines bearing CHF2, CClF2, CBrF2, CIF2, C2F5, C3F7, C4F9, C4HF8, C5F11 and C6HF12 groups, synthetically valuable reagents for preparation of fluorinated amino‐compounds of high pharmaceutical potential.
Unexpected Diversity within Solid‐State Structures of Methanetrisulfonate Salts
Authors: Oelkers Benjamin , Schaffner Dirk , Sun Yu 
Published: September 2016

AbstractThe structural properties of various salts of methanetrisulfonic acid (H3mts) are described, spanning the free acid, ammonium and alkali metals (Na, K, Cs), first row transition metals (Cr, Co−Zn), and lead. A number of different coordination modes is found, including unexpected motifs such as the κ3O1,4,7 coordination in the lead salt and anions of the type [M(H2O)4(κ2O1,4‐mts)]− (M=Co, Ni, Zn), which do not seem to be persistent in aqueous solution.
A Lysophosphatidic Acid Receptors 1 and 3 Axis Governs Cellular Senescence of Mesenchymal Stromal Cells and Promotes Growth and Vascularization of Multiple Myeloma
Authors: Kanehira Masahiko , Fujiwara Tohru , Nakajima Shinji , Okitsu Yoko , Onishi Yasushi , Fukuhara Noriko , Ichinohasama Ryo , Okada Yoshinori , Harigae Hideo 
Published: September 2016

Abstract
Mesenchymal stromal cells (MSCs) are multipotent progenitor cells and there is much interest in how MSCs contribute to the regulation of the tumor microenvironment. Whether MSCs exert a supportive or suppressive effect on tumor progression is still controversial, but is likely dependent on a variety of factors that are tumor-type dependent. Multiple myeloma (MM) is characterized by growth of malignant plasma cells in the bone marrow. It has been shown that the progression of MM is governed by MSCs, which act as a stroma of the myeloma cells. Although stroma is created via mutual communication between myeloma cells and MSCs, the mechanism is poorly understood. Here we explored the role of lysophosphatidic acid (LPA) signaling in cellular events where MSCs were converted into either MM-supportive or MM-suppressive stroma. We found that myeloma cells stimulate MSCs to produce autotaxin, an indispensable enzyme for the biosynthesis of LPA, and LPA receptor 1 (LPA1) and 3 (LPA3) transduce opposite signals to MSCs to determine the fate of MSCs. LPA3-silenced MSCs (siLPA3-MSCs) exhibited cellular senescence-related phenotypes in vitro, and significantly promoted progression of MM and tumor-related angiogenesis in vivo. In contrast, siLPA1-MSCs showed resistance to cellular senescence in vitro, and efficiently delayed progression of MM and tumor-related angiogenesis in vivo. Consistently, anti-MM effects obtained by LPA1-silencing in MSCs were completely reproduced by systemic administration of Ki6425, an LPA1 antagonist. Collectively, our results indicate that LPA signaling determines the fate of MSCs and has potential as a therapeutic target in MM.
Reactive Oxygen Species Impair the Function of CD90+ Hematopoietic Progenitors Generated from Human Pluripotent Stem Cells
Authors: Rönn Roger E. , Guibentif Carolina , Saxena Shobhit , Woods Niels-Bjarne 
Published: September 2016

Abstract
Cell stressors, such as elevated levels of reactive oxygen species (ROS), adversely affect hematopoietic stem cell (HSC) reconstituting ability. However, the effects of ROS have not been evaluated in the context of hematopoietic development from human pluripotent stem cells (hPSCs). Using our previously described in vitro system for efficient derivation of hematopoietic cells from hPSCs, we show that the vast majority of generated hematopoietic cells display supraphysiological levels of ROS compared to fresh cord blood cells. Elevated ROS resulted in DNA damage of the CD34+ hematopoietic fraction and, following functional assays, reduced colony formation and impaired proliferative capacity. Interestingly, all the proliferative potential of the most primitive hematopoietic cells was limited to a small fraction with low ROS levels. We show that elevation of ROS in hPSC-derived hematopoietic cells is contributed by multiple distinct cellular processes. Furthermore, by targeting these molecular processes with 4 unique factors, we could reduce ROS levels significantly, yielding a 22-fold increase in the most primitive CD90+ CD34+ hematopoietic cells with robust growth capacity. We demonstrate that the ROS reducing factors specifically reduced ROS in more primitive hematopoietic fractions, in contrast to endothelial cells that maintained low ROS levels in the cultures. We conclude that high levels of ROS in in vitro differentiation systems of hPSCs is a major determinant in the lack of ability to generate hematopoietic cells with similar proliferation/differentiation potential to in vivo hematopoietic progenitors, and suggest that elevated ROS is a significant barrier to generating hPSC-derived repopulating HSCs.
Progressive lesions of central nervous system in microcephalic fetuses with suspected congenital Zika virus syndrome
Authors: Sarno M. , Aquino M. , Pimentel K. , Cabral R. , Costa G. , Bastos F. , Brites C. 
Published: September 2016

ABSTRACTObjectiveTo describe the pattern and progression of central nervous system (CNS) lesions in microcephalic fetuses with suspected Zika virus (ZIKV) infection.MethodsIn this prospective study in Salvador, Brazil, we analyzed fetuses diagnosed with microcephaly and suspected ZIKV infection after a routine primary care ultrasound scan between July 2015 and February 2016 raised suspicion of fetal microcephaly. The pregnancies were followed with serial ultrasound scans until delivery at one of the three main referral centers for fetal abnormalities in Salvador, Brazil. Microcephaly was diagnosed when the head circumference was two or more SDs below the mean for gestational age and its relationship with ZIKV infection was defined according to the World Health Organization's criteria. All women were interviewed, to assess potential factors associated with fetal microcephaly. Serology test results for toxoplasmosis, cytomegalovirus, rubella, syphilis and human immunodeficiency virus (HIV) were recorded, as were previous routine ultrasound results. Signs/symptoms of infection during the pregnancy were noted.ResultsOf 60 cases of suspected ZIKV‐related fetal microcephaly seen during the study period, eight were excluded due to serological evidence of other congenital infections or major ultrasound chromosomal markers. In the remaining 52 fetuses, microcephaly was diagnosed between 19 and 40 (median, 27.7; interquartile range, 23.4–32.0) weeks of gestation. The main ultrasound findings were: ventriculomegaly (65.4% of cases), cerebral calcifications (44.2%) and posterior fossa abnormalities (32.7%). 9.6% presented with arthrogryposis as an associated finding. Microcephaly was an isolated finding in four cases (7.7%). While ventriculomegaly was progressive in 41.2% of cases with this finding, the velocity of head circumference increase decreased progressively in almost all cases. Exanthematic disease was present in the majority (86.5%) of the women, 67.3% presenting in the first trimester of pregnancy. Additional lesions were detected after birth in 71.4% of the 35 cases with neonatal follow‐up.ConclusionsThe majority of cases of congenital ZIKV syndrome have other ultrasonographic findings in addition to microcephaly. ZIKV‐related CNS anomalies present mainly as progressive CNS lesions and slowing rate of growth of the fetal head, and this seems to be evident only in the late second trimester, even when maternal infection occurs in the first trimester. Other ultrasound findings, such as ventriculomegaly, brain calcifications and posterior fossa destruction lesions, are also common in this congenital syndrome. Posterior fossa destruction lesions and arthrogryposis are an uncommon finding in other congenital infections, perhaps suggesting a novel severe congenital syndrome associated with fetal ZIKV. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.
Is curved three‐dimensional ultrasound reconstruction needed to assess the warped pelvic floor plane?
Authors: Youssef A. , Cavalera M. , Pacella G. , Salsi G. , Morganelli G. , Montaguti E. , Cataneo I. , Pilu G. , Rizzo N. 
Published: September 2016

ABSTRACTObjectivesCaudal distension of the female pelvic floor is common and results in perineal descent and a caudally curved levator hiatus (warping). Image reconstruction of the pelvic floor using currently available ultrasound techniques involves a linear approach (flat‐plane reconstruction). We aimed to evaluate the feasibility, reproducibility and potential usefulness of a new three‐dimensional (3D) technique capable of reconstructing a curved plane of the levator hiatus.MethodsPrimiparous women were recruited to undergo a 3D/four‐dimensional transperineal ultrasound examination 3–6 months after delivery. Levator ani muscle warping was evaluated on Valsalva maneuver by measuring the distance between the plane extending from the pubic rami to the anorectal angle and the plane of minimal hiatal dimensions on the coronal plane. Warping distance was used to reconstruct a curved plane of the levator hiatus using the curved OmniView volume contrast imaging (VCI) technique (C‐OV). Intra‐ and interobserver reproducibility of the C‐OV technique were assessed, as was intermethod agreement between the C‐OV technique and the linear OmniView‐VCI (L‐OV) technique, for the measurement of levator hiatal area on Valsalva maneuver.ResultsMeasurement of the levator hiatal area using C‐OV was feasible in all 84 women recruited. The warping distance ranged from −3.5 to 9.7 mm, confirming that the 1–2‐cm slice thickness traditionally used for linear reconstruction was adequate for proper assessment of levator hiatal area in our population. C‐OV showed excellent intra‐ and interobserver reproducibility, as well as excellent agreement with the L‐OV technique for measuring levator hiatal area. No systematic difference was demonstrated in any of the reproducibility studies performed.Conclusions3D reconstruction of the warped levator hiatal plane is feasible and highly reproducible. In our population, reconstruction of a curved plane to correct for levator hiatal warping did not offer any benefit over the traditionally performed linear reconstruction. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.
Diagnostic accuracy of midtrimester antenatal ultrasound for multicystic dysplastic kidneys
Authors: Scala C. , McDonnell S. , Murphy F. , Leone Roberti Maggiore U. , Khalil A. , Bhide A. , Thilaganathan B. , Papageorghiou A. T. 
Published: September 2016

ABSTRACTObjectivesTo establish the diagnostic accuracy of obstetric ultrasound at a tertiary fetal medicine center in the prenatal detection of unilateral and bilateral multicystic dysplastic kidney (MCDK) in fetuses in which this condition was suspected, and to undertake a systematic review of the relevant literature.MethodsThis was a retrospective observational study of all cases referred to a regional tertiary fetal medicine unit due to suspicion of either unilateral or bilateral MCDK between 1997 and 2015. Diagnosis was confirmed by postnatal ultrasound reports or postmortem examination. The accuracy of prenatal ultrasound in the diagnosis of MCDK was calculated. Using a systematic search strategy we also performed a review of the literature regarding the prenatal diagnosis and diagnostic accuracy of MCDK.ResultsWe included 144 women in our analysis; 37 (25.7%) opted for pregnancy termination (TOP) (due to unilateral MCDK with additional abnormalities, suspected bilateral MCDK or severe obstructive uropathy). Complete pre‐ and postnatal data were available in 126 pregnancies, including 104 livebirths, 19 TOPs with postmortem findings available and three intrauterine fetal deaths. Two infants died shortly after birth (due to known bilateral MCDK or known cranial vault defect). The overall number of cases of MCDK confirmed postnatally was 100; of these, 98 were diagnosed prenatally (true positive), while two were thought to be hydronephrosis prenatally (false negative) and the diagnosis of MCDK was made after birth. In nine cases, the initial antenatal diagnosis of suspected MCDK was revised, either later in pregnancy (n = 2) or postnatally (n = 7) (false positive). Overall, the diagnostic accuracy in our population for the use of antenatal ultrasound to detect MCDK was 91.3%, while that reported in the existing literature was found to range from 53.3% to 100%. MCDK was isolated in the majority (71%) of cases, while in 29% of cases it was found to be associated with other renal and extrarenal fetal abnormalities.ConclusionsAntenatal ultrasound had a diagnostic accuracy of about 91% in the prediction of postnatal MCDK and can therefore be used to guide antenatal counseling. However, prenatal or postnatal revision of the diagnosis occurred in about 7% of cases and parents should be counseled appropriately. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.
Ankle Reconstruction in Fibular Hemimelia: New Approach
Authors: Hefny Hany , Elmoatasem ElHussein M. , Mahran Mahmoud , Fayyad Tamer , Elgebeily Mohamed A. , Mansour Ahmed , Hefny Mamdouh 
Published: September 2016

Background Fibular hemimelia is a congenital disorder that is characterized by the absence of the fibula that could be either partial or complete. Successful management aims to restore normal weight bearing and normal limb length. The introduction of the Ilizarov method of limb lengthening has provided an attractive alternative to amputation. During lengthening, the tight posterolateral soft-tissue structures, the thick fibrous fibular band, and the shortened Achilles tendon become tighter and transfer a valgus force to the talus and calcaneus, further aggravating the deformity. Questions/Purposes We have developed a strategy to address this in patients with Paley type III fibular hemimelia via ankle reconstruction that provides posterolateral stability and buttressing of the ankle and hind foot by reconstructing the lateral buttress. This is achieved through excision of the fibrous fibular anlage, centralization of the ankle, restoring talocalcaneal coronal alignment, and reconstruction of the lateral malleolus by transplanting the cartilaginous remnant of the lateral malleolus or by crafting a bone block autograft taken from the iliac crest or tibia. Methods A prospective non-randomized clinical trial included ten ankles in eight patients with fibular hemimelia Paley type III (two patients had bilateral deformity). The patients’ ages ranged from 7 to 36 months. Results After a follow-up ranging from 48 to 96 months, a stable plantigrade foot was achieved in nine ankles; one ankle had residual equinus, five ankles had residual valgus heel, and eight ankles had complete range of motion of the ankle, whereas one patient lost 5° of dorsiflexion. One ankle had equinus deformity. Conclusions To achieve satisfactory results, a stable plantigrade foot and ankle is necessary in patients with fibular hemimelia before attempting to equalize limb length discrepancy. It is important to reconstruct the ankle through an extra-articular soft tissue release, anlage resection, osteotomies, and restoring the abnormal talocalcaneal relationship before any attempt to equalize LLD.
Carbonates and sources of fluids in ores and metasomatites of the Ermakovka fluorite-bertrandite-phenacite deposit (western Transbaikalia)
Authors: Ripp G.S. , Izbrodin I.A. , Doroshkevich A.G. , Rampilov M.O. , Lastochkin E.I. , Posokhov V.F. 
Published: September 2016

Abstract
We present results of isotope-geochemical study of the Ermakovka F–Be deposit, including data on the oxygen and carbon isotope compositions in dolomite and calcite marbles and in carbonates accompanying skarns, of early and late stages of ore formation and of post-ore parageneses. To elucidate the sources of fluids participated in the ore formation, we calculated the oxygen isotope composition in water and the hydrogen isotope composition in hydroxyl-containing minerals. Phlogopite in marbleized dolomites, vesuvianite and amphibole in skarns, eudidimite and bertrandite in ore parageneses, and bavenite formed during post-ore processes are analyzed. Most of the ore-stage minerals are depleted in heavy oxygen. Their δ18O values are lower than 5–6‰ (SMOW). Oxygen in carbonate minerals of the initial stage (dolomite and bastnaesite) is heavier (1.3–4.9‰) than that in calcite (+ 2 to –3.7‰). The δ18O values of water in equilibrium both with carbonate and with silicate minerals (–4 to –14‰) suggest the contribution of meteoric water to the mineral formation. A magmatic fluid (δ18O from + 6 to + 9‰) participated in the skarn formation at the initial stage, and a meteoric fluid, at the final stage (δ18O from –1 to –9‰). A meteoric source is confirmed by the depleted hydrogen isotope composition in minerals (δD from –119 to –192‰).
G/G/∞ queues with renewal alternating interruptions
Authors: Pang Guodong , Zhou Yuhang 
Published: September 2016

AbstractWe study G/G/∞ queues with renewal alternating service interruptions, where the service station experiences `up' and `down' periods. The system operates normally in the up periods, and all servers stop functioning while customers continue entering the system during the down periods. The amount of service a customer has received when an interruption occurs will be conserved and the service will resume when the down period ends. We use a two-parameter process to describe the system dynamics:Xr(t,y) tracking the number of customers in the system at timetthat have residual service times strictly greater thany. The service times are assumed to satisfy either of the two conditions: they are independent and identically distributed with a distribution of a finite support, or are a stationary and weakly dependent sequence satisfying the ϕ-mixing condition and having a continuous marginal distribution function. We consider the system in a heavy-traffic asymptotic regime where the arrival rate gets large and service time distribution is fixed, and the interruption down times are asymptotically negligible while the up times are of the same order as the service times. We show the functional law of large numbers and functional central limit theorem (FCLT) for the processXr(t,y) in this regime, where the convergence is in the space 𝔻([0,∞), (𝔻,L1)) endowed with the SkorokhodM1topology. The limit processes in the FCLT possess a stochastic decomposition property.
On the relation between graph distance and Euclidean distance in random geometric graphs
Authors: Díaz J. , Mitsche D. , Perarnau G. , Pérez-Giménez X. 
Published: September 2016

Abstract
Given any two vertices u, v of a random geometric graph G(n, r), denote by dE(u, v) their Euclidean distance and by dE(u, v) their graph distance. The problem of finding upper bounds on dG(u, v) conditional on dE(u, v) that hold asymptotically almost surely has received quite a bit of attention in the literature. In this paper we improve the known upper bounds for values of r=ω(√logn) (that is, for r above the connectivity threshold). Our result also improves the best known estimates on the diameter of random geometric graphs. We also provide a lower bound on dE(u, v) conditional on dE(u, v).
Degrees and distances in random and evolving apollonian networks
Authors: Kolossváry István , Komjáthy; Júlia , Vágó Lajos 
Published: September 2016

Abstract
In this paper we study random Apollonian networks (RANs) and evolving Apollonian networks (EANs), in d dimensions for any d≥2, i.e. dynamically evolving random d-dimensional simplices, looked at as graphs inside an initial d-dimensional simplex. We determine the limiting degree distribution in RANs and show that it follows a power-law tail with exponent τ=(2d-1)/(d-1). We further show that the degree distribution in EANs converges to the same degree distribution if the simplex-occupation parameter in the nth step of the dynamics tends to 0 but is not summable in n. This result gives a rigorous proof for the conjecture of Zhang et al. (2006) that EANs tend to exhibit similar behaviour as RANs once the occupation parameter tends to 0. We also determine the asymptotic behaviour of the shortest paths in RANs and EANs for any d≥2. For RANs we show that the shortest path between two vertices chosen u.a.r. (typical distance), the flooding time of a vertex chosen uniformly at random, and the diameter of the graph after n steps all scale as a constant multiplied by log n. We determine the constants for all three cases and prove a central limit theorem for the typical distances. We prove a similar central limit theorem for typical distances in EANs.