bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laser desorption/ionization mediated by bionanostructures from microalgae
Authors: Jaschinski Tino , Svatoš Aleš , Pohnert Georg 
Published: December 2012

RATIONALEOrganic matrices are the state‐of‐the‐art ionization mediators in Laser Desorption/Ionization Mass Spectrometry (LDI‐MS). Despite improvements in understanding matrix chemistry, interfering matrix‐related signals complicate the analysis. Surface‐assisted LDI techniques like desorption/ionization on silicon (DIOS) or nanostructure initiator mass spectrometry (NIMS) provide promising alternatives but rely often on elaborate materials.METHODSWe introduce nanopatterned biomineralized cell walls of microalgae as easily accessible biological surfaces that support the ionization of embedded molecules in LDI‐MS. Microalgae cell walls were cleaned through oxidation and washing before pipetting on a stainless‐steel matrix‐assisted laser desorption/ionization (MALDI) target. Added molecules were efficiently ionized in positive and negative ionization mode in common MALDI sources. The method was rigorously validated by comparison with established MALDI experiments.RESULTSIonization of PEG600, D‐sphingosine and raffinose was successfully mediated by nanostructured cell wall preparations from two different microalgae. Without any change in protocol, steric acid could be detected in the negative ionization mode. Ionization is also supported by commercially available celite, a material containing mineralized diatom cell walls. Characteristic ingredients of fresh coffee were detected in LDI‐MS after pipetting it on celite without further sample preparation. Caffeine and saccharose were detected in positive and characteristic fatty acids in negative ionization mode. Detection limits were comparable to established MALDI experiments.CONCLUSIONSBionanostructure‐enhanced ionization allows the analysis of a diverse selection of analytes including polymers, sugars, amino alcohols, and organic acids without interfering matrix signals. We also show that celite, a commercially available porous material containing mineralized algal bionanostructures, supports LDI‐MS. Copyright © 2012 John Wiley & Sons, Ltd.
Laser desorption/ionization mass spectrometric analysis of surfactants on functionalized carbon nanotubes
Authors: Cegłowski Michał , Schroeder Grzegorz 
Published: December 2012

RATIONALERecently, unmodified and carboxylated carbon nanotubes have been used as assisting surfaces laser desorption/ionization (LDI) in mass spectrometry. The functionalization of carbon nanotubes with organic compounds should lead to a gamut of other promising LDI‐assisting surfaces.METHODSCarboxylated carbon nanotubes were functionalized with sinapinic acid either covalently or by creating an ionic macro‐complex. Polyether‐based surfactants were used as analytes to examine the properties of these new matrices. Mass spectrometric analysis was conducted on a LDI‐quadrupole time‐of‐flight (QTOF) mass spectrometer. Carbon nanotube surfaces were deposited from suspension using the dried‐droplet method.RESULTSThe functionalization of the carbon nanotubes was confirmed with Fourier transform infrared (FTIR) spectroscopy. The usefulness of each material was examined with two poly(ethylene glycol) hexadecyl ether amphiphiles (Brij® 52 and Brij® 56) and a poly(ethylene glycol) monomethyl ether as analytes. Generally, the mass spectra obtained with carbon nanotubes covalently functionalized with sinapinic acid as a matrix had peaks with higher intensities than those obtained with carbon nanotubes functionalized by ionic macro‐complex formation.CONCLUSIONSThe presented new materials based on functionalized carbon nanotubes are effective in the LDI mass analysis of polyether amphiphiles and poly(ethylene glycol) monomethyl ether. This type of assisting surfaces can be highly modified by appropriate functionalization procedures. Copyright © 2012 John Wiley & Sons, Ltd.
Matrix effect in matrix‐assisted laser desorption/ionization mass spectra of derivatized oligomeric polyols
Authors: Borisov Roman S. , Polovkov Nikolai Yu. , Zhilyaev Dmitry I. , Zaikin Vladimir G. 
Published: December 2012

RATIONALEHerein we describe a strong matrix effect observed in the matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐ToF) mass spectra of silylated glycerol alkoxylates and manifested in the loss of the silyl groups in the presence of carboxyl‐containing matrices.METHODSCommercially available glycerol alkoxylates containing three end OH groups as well as three matrices – 2,5‐dihydroxybenzoic acid (DHB), 3‐indoleacrylic acid (IAA) and 1,8,9‐anthracenetriol (dithranol) – were chosen for the investigation. N,O‐Bis(trimethylsilyl)trifluoroacetamide containing 1% trimethylchlorosilane, acetic anhydride and a formylation mixture (formic acid/acetyl chloride) were used for derivatization. Initial oligomers and derivatized products were analyzed by MALDI‐ToF‐mass spectrometry (MS) on an Autoflex II instrument, equipped with a nitrogen laser (λ 337 nm), in positive ion reflectron mode.RESULTSOnly [M + Na]+ ions were observed for underivatized polymers and for completely derivatized polymers in the presence of DHB and dithranol, respectively. In the case of IAA the mass spectra revealed sets of peaks for underivatized, and for partially and completely derivatized oligomers. No similar 'matrix effect' was observed in the case of acylated glycerol alkoxylates (acyl = formyl, acetyl): only peaks for completely derivatized oligomers were obtained in all matrices: DHB, IAA and dithranol. Using 1,9‐nonandiol, we showed that the 'matrix effect' was due to trans‐silylation of carboxyl‐containing matrices (DHB and IAA) during co‐crystallization of silylated oligomers and matrices.CONCLUSIONSThe obtained results show that matrix molecules can participate as reactive species in MALDI‐ToF‐MS experiments. The matrix should be carefully chosen when a derivatization approach is applied because the analysis of spectra of the completely derivatized products is particularly desirable in the quantitative determination of functional end‐groups. Copyright © 2012 John Wiley & Sons, Ltd.
Single Quantum Dot Analysis Enables Multiplexed Point Mutation Detection by Gap Ligase Chain Reaction
Authors: Song Yunke , Zhang Yi , Wang Tza‐Huei 
Published: December 2012

AbstractGene point mutations present important biomarkers for genetic diseases. However, existing point mutation detection methods suffer from low sensitivity, specificity, and a tedious assay processes. In this report, an assay technology is proposed which combines the outstanding specificity of gap ligase chain reaction (Gap‐LCR), the high sensitivity of single‐molecule coincidence detection, and the superior optical properties of quantum dots (QDs) for multiplexed detection of point mutations in genomic DNA. Mutant‐specific ligation products are generated by Gap‐LCR and subsequently captured by QDs to form DNA–QD nanocomplexes that are detected by single‐molecule spectroscopy (SMS) through multi‐color fluorescence burst coincidence analysis, allowing for multiplexed mutation detection in a separation‐free format. The proposed assay is capable of detecting zeptomoles of KRAS codon 12 mutation variants with near 100% specificity. Its high sensitivity allows direct detection of KRAS mutation in crude genomic DNA without PCR pre‐amplification.
A new approach to authenticating and encrypting Voice over Internet Protocol communications
Authors: Lago‐Fernández J. , Gil‐Castiñeira F. , González‐Castaño F.J. , Román‐Portabales A. 
Published: December 2012

SUMMARYTraditionally, call authentication and security have not raised user concerns because wiretapping requires physical access to the phone line and special equipment. However, Voice over Internet Protocol (VoIP) communications are becoming increasingly popular, and there is the perception that they may be easier to intercept or impersonate (thus creating higher demand for security solutions), especially if the connection occurs over wireless links. The Session Initiation Protocol is widely used for managing voice and video communications over the Internet, and the Real‐time Transport Protocol is used to carry voice and/or video streams. Session Initiation Protocol, however, was not designed with security in mind and is vulnerable to attacks.Furthermore, there are cases in which it is necessary to authenticate the call participants (e.g., when they are asked to disclose confidential information). There are few practical solutions to this problem, essentially because they require complex infrastructures to manage keys and certificates.In this paper, we solve this problem with a novel approach: the use of national public key infrastructures in combination with national Electronic Identity smart cards, created by governments to execute trusted electronic transactions and establish trusted identities. In addition, we will show how our approach enables new use cases (e.g., institutions – hospitals, banks, government, etc. – can be confident that they exchange confidential information to the intended person and vice versa) and simplifies the steps necessary to secure and authenticate a VoIP communication with ZRTP, simplifying and therefore encouraging the use of secure VoIP communications between authenticated users. Copyright © 2012 John Wiley & Sons, Ltd.
Simulation on locating Partial Discharge source occurring on distribution line by estimating the DOA of emitted EM waves
Authors: Tian Ye , Kawada Masatake 
Published: December 2012

AbstractA new method for locating the position of partial discharge (PD), which occurs on distribution line, is presented. The method uses the direction‐of‐arrival (DOA) of electromagnetic (EM) waves emitted from PD source. The DOAs of EM waves in azimuth and elevation angles are estimated by using the two‐dimensional improved coherent signal subspace method (2D I‐CSM). The position of PD can be located as the intersection of DOAs estimated at two points. In this paper, the finite difference time domain (FDTD) method is applied to simulate the propagation of EM waves emitted from PD, which occurs on distribution line. The proposed method is applied to locate the position of PD based on the simulation results. The method is shown to be useful for locating the position of PD in multipath environment. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Hydrated Rare Earth Structural Networks containing the Phenylene‐1, 2‐dioxydiacetate (PDDA) Ligand
Authors: Behrsing Thomas , Deacon Glen B. , Junk Peter C. , Skelton Brian W. , Sobolev Alexandre N. , White Allan H. 
Published: December 2012

AbstractReaction of LnCl3 with Na2(PDDA) (PDDA = phenylene‐1, 2‐dioxydiacetate) in a 1 to 2 mol ratio in aqueous solution yielded [Ln2(PDDA)3(H2O)6]·2H2O, structurally characterized for Ln = Ce (1), Sm (2) (redetermination), Tb (3) and Y (4) in a monoclinic C2/c array, a second related structural form [orthorhombic, Pbcn] being obtained for Tb (5), Ho (6) and Er (7). The ‘domains of existence' of these two previously described forms are now extended to Ce–Dy, Y, and Eu–Er, respectively. Reaction under the same conditions for the heavier Yb3+ ion yielded [Yb2(PDDA)3(H2O)6](∞|∞)·4H2O (8), orthorhombic, Pbca. In the case of Ln = La the bimetallic species [NaLa(PDDA)2(H2O)2](∞|∞)·4H2O (9) was obtained, while reaction of LnCl3 with Na2(PDDA) in a 1 to 3 mol ratio led to the isolation of the isotypic (monoclinic, P21/c) [NaLn(PDDA)2(H2O)2](∞|∞)·4H2O) for Ln = Ce (10) and Sm (12). With the smaller Ln = Yb, the more definitively bimetallic [NaYb(PDDA)2(H2O)2](∞|∞)·3H2O (13) (triclinic, P$\bar{1}$)) was obtained, the trihydrate solvation ascribed differing from that recorded (dihydrate) in a cosynchronous report.
Energetics and life‐history of bats in comparison to small mammals
Authors: Becker N. I. , Encarnação J. A. , Tschapka M. , Kalko E. K. V. 
Published: December 2012

AbstractMammals can be aligned along a slow‐fast life‐history continuum and a low–high metabolic rate continuum based on their traits. Small non‐volant mammals occupy the fast/high end in both continua with high reproductive rates and short life spans linked with high mass‐specific metabolic rates. Bats occupy the high end of the metabolic continuum, but the slow end of the life‐history continuum with low reproductive rates and long life spans. Typically, both continua are linked, and similar life‐history traits of species are reflected in more similar metabolic rates. We therefore hypothesized that metabolic rates are similar in species with similar life‐history traits. Resting metabolic rates (RMR) were measured for three ecologically and morphologically similar sympatric bat species (Myotis nattereri,M. bechsteinii, andPlecotus auritus; Vespertilionidae) and compared to data from other similar‐sized, temperate insectivorous mammals with other life‐history strategies. The bat species share similar life‐histories and RMRs, both of which differ from the remaining mammals and therefore supporting our hypothesis. To verify that bats are similar in RMR, two energetically contrasting periods were compared. RMRs in post‐lactating females did not differ between bat species. It was, however, positively correlated with parasite load in bothMyotisspecies. However, RMRs differed during energy‐demanding pregnancy whereM. nattererihad the significantly lowest RMR, suggesting metabolic compensation as an energy‐saving strategy. We conclude that the energy requirements of bat species with similar life‐history traits resemble each other during periods of low energetic demands and are more similar to each other than to other small temperate mammals.
Induced pluripotent stem cells in reproductive medicine
Authors: Teramura Takeshi , Frampton John 
Published: December 2012

AbstractDespite recent advances in reproductive medicine, there are still no effective treatments for severe infertility caused by congenital absence of germ cells or gonadotoxic treatments during prepubertal childhood. However, the development of technologies for germ cell formation from stem cells in vitro, induction of pluripotency from somatic cells, and production of patient‐specific pluripotent stem cells may provide new solutions for treating these severe fertility problems. It may be possible to produce germ cells in vitro from our own somatic cells that can be used to restore fertility. In addition, these technologies may also bring about novel therapies by helping to elucidate the mechanisms of human germ cell development. In this review, we describe the current approaches for obtaining germ cells from pluripotent stem cells, and provide basic information about induction of pluripotency and germ cell development.
Biological features of core networks that result from a high-fat diet in hepatic and pulmonary tissues in mammary tumour-bearing, obesity-resistant mice
Authors: Kim Eun Ji , Oh Hea Young , Heo Hyoung-Sam , Hong Ji Eun , Jung Sung-Jae , Lee Ki Won , Park Jong Hoon , Hur Cheol-Goo , Park Jung Han Yoon 
Published: December 2012

We previously demonstrated that the chronic consumption of a high-fat diet (HFD) promotes lung and liver metastases of 4T1 mammary carcinoma cells in obesity-resistant BALB/c mice. To examine early transcriptional responses to tumour progression in the liver and lungs of HFD-fed mice, 4-week-old female BALB/c mice were divided into four groups: sham-injected, control diet (CD)-fed; sham-injected, HFD-fed (SH); 4T1 cell-injected, CD-fed (TC); 4T1 cell-injected, HFD-fed (TH). Following 16 weeks of either a CD or HFD, 4T1 cells were injected into the mammary fat pads of mice in the TC and TH groups and all mice were continuously fed identical diets. At 14 d post-injection, RNA was isolated from hepatic and pulmonary tissues for microarray analysis of mRNA expression. Functional annotation and core network analyses were conducted for the TH/SH Unique gene set. Inflammation in hepatic tissues and cell mitosis in pulmonary tissues were the most significant biological functions in the TH/SH Unique gene set. The biological core networks of the hepatic TH/SH Unique gene set were characterised as those genes involved in the activation of acute inflammatory responses (Orm1, Lbp, Hp and Cfb), disordered lipid metabolism and deregulated cell cycle progression. Networks of the pulmonary Unique gene set displayed the deregulation of cell cycle progression (Cdc20, Cdk1 and Bub1b). These HFD-influenced alterations may have led to favourable conditions for the formation of both pro-inflammatory and pro-mitotic microenvironments in the target organs that promote immune cell infiltration and differentiation, as well as the infiltration and proliferation of metastatic tumour cells.
A whole-of-population study of the prevalence and patterns of criminal offending in people with schizophrenia and other mental illness
Authors: Morgan V. A. , Morgan F. , Valuri G. , Ferrante A. , Castle D. , Jablensky A. 
Published: December 2012

BackgroundLarge epidemiological studies are needed to better understand the prevalence and profile of offending by people with mental illness. This study used a whole-of-population design to examine the prevalence, type and pattern of offending across all psychiatric diagnoses, including schizophrenia, compared to the general population.MethodWe used whole-of-population longitudinal record-linked data for a cohort of all Western Australians born 1955–1969 to determine arrest history over the period 1985–1996 and to ascertain recorded history of psychiatric illness. Of the cohort, 116 656 had been arrested and 40 478 were on the psychiatric case register.ResultsThe period prevalence of arrest for people with any psychiatric illness was 32.1%. The highest arrest prevalence, by diagnostic category, was for substance use disorders (59.4%); the prevalence for schizophrenia was 38.7%. Co-morbid substance use disorders significantly increased risk of arrest in people with schizophrenia. The prevalence of mental illness among offenders was 11.1%: 6.5% of offenders had substance use disorders and 1.7% had schizophrenia. For the majority of offenders with a psychiatric illness, first arrest preceded first contact with mental health services; for schizophrenia only, this proportion was increasing over time. The mean percentage annual change in the number of arrests during 1985–1996 rose significantly for offenders with a psychiatric illness other than schizophrenia and dropped significantly for those with no mental illness. Compared to non-psychiatric offenders, offenders with schizophrenia were more likely to offend alone, to offend in open places and to target strangers.ConclusionsOur findings open the way to an informed approach to the management of offenders with mental illness.
Perceptions de l’arrêt de la dialyse et des traitements de maintien de la vie chez la clientèle québécoise en hémodialyse hospitalière: comparaison selon l’âge
Authors: Gagnon Judith , Saint-Arnaud Jocelyne , Bourdeau Marc , Côté Josée , Chapados Claire , Michaud Cécile 
Published: December 2012

ABSTRACTThe End-Stage Renal Disease population is aging. Considering that hemodialysis is a treatment that maintains and prolongs life, this descriptive-comparative study looks at the perceptions of patients according to age group -<65 years, n=121 and ≥65 years, n=123, as it pertains to dialysis treatment cessation and life-sustaining treatments. Results: Older patients are more indecisive as to what dialysis treatment cessation may actually represent for them (p=0,01). They expressed a greater need for support from the health care team if they decided to stop dialysis treatments (p=0,02); a greater involvement from the physician (p=0,04); and, in the event patients could not take part in end-of-life decision-making, they would give priority to the wishes of loved ones instead of their own wishes (p=0,01). Conclusion: Advanced care planning is necessary to demystify hemodialysis withdrawal and to support patients and their loved ones through this process.
DIPRA: A user‐friendly program to model multi‐element diffusion in olivine with applications to timescales of magmatic processes
Authors: Girona Társilo , Costa Fidel 
Published: December 2012

AbstractModeling the diffusion of elements in olivine from volcanic rocks has recently become one of the most useful techniques to determine the timescales of the processes that occur in magma reservoirs before eruptions. However, many potential users are not versed in the numerical methods needed to solve the diffusion equation for timescale determinations. Here we present DIPRA (Diffusion Process Analysis), a user‐friendly computer tool that models easily and intuitively the olivine chemical zoning by performing an automatic, visual, and quick fit to the natural profiles. The code is developed under a finite difference scheme and allows simultaneous modeling of diffusion of Fe, Mg, Mn, Ni, and Ca. DIPRA accounts for most variables that affect the diffusivity, including temperature, pressure, oxygen fugacity, major element composition, and anisotropy. Initial and boundary conditions can be done as complex as desired, including changing boundary composition with time. Such versatility allows modeling the large variety of scenarios that are characteristic of volcanic systems. We also have implemented a methodology to estimate objectively the uncertainties of the timescales from the uncertainties of the data and temperature. We expect that our application will increase the number and quality of timescale determinations from crystal zoning studies. It may be also useful as a teaching resource for higher education courses.
Butyrate-producing Clostridium cluster XIVa species specifically colonize mucins in an in vitro gut model
Authors: Van den Abbeele Pieter , Belzer Clara , Goossens Margot , Kleerebezem Michiel , De Vos Willem M , Thas Olivier , De Weirdt Rosemarie , Kerckhof Frederiek-Maarten , Van de Wiele Tom 
Published: December 2012

Abstract
The human gut is colonized by a complex microbiota with multiple benefits. Although the surface-attached, mucosal microbiota has a unique composition and potential to influence human health, it remains difficult to study in vivo. Therefore, we performed an in-depth microbial characterization (human intestinal tract chip (HITChip)) of a recently developed dynamic in vitro gut model, which simulates both luminal and mucosal gut microbes (mucosal-simulator of human intestinal microbial ecosystem (M-SHIME)). Inter-individual differences among human subjects were confirmed and microbial patterns unique for each individual were preserved in vitro. Furthermore, in correspondence with in vivo studies, Bacteroidetes and Proteobacteria were enriched in the luminal content while Firmicutes rather colonized the mucin layer, with Clostridium cluster XIVa accounting for almost 60% of the mucin-adhered microbiota. Of the many acetate and/or lactate-converting butyrate producers within this cluster, Roseburia intestinalis and Eubacterium rectale most specifically colonized mucins. These 16S rRNA gene-based results were confirmed at a functional level as butyryl-CoA:acetate-CoA transferase gene sequences belonged to different species in the luminal as opposed to the mucin-adhered microbiota, with Roseburia species governing the mucosal butyrate production. Correspondingly, the simulated mucosal environment induced a shift from acetate towards butyrate. As not only inter-individual differences were preserved but also because compared with conventional models, washout of relevant mucin-adhered microbes was avoided, simulating the mucosal gut microbiota represents a breakthrough in modeling and mechanistically studying the human intestinal microbiome in health and disease. Finally, as mucosal butyrate producers produce butyrate close to the epithelium, they may enhance butyrate bioavailability, which could be useful in treating diseases, such as inflammatory bowel disease.