bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclen‐Based Cationic Lipids Containing Carbamate Linkages as Efficient Gene Delivery Vectors with Low Toxicity
Authors: Huang Qing‐Dong , Ren Jiang , Chen Hong , Ou Wen‐Jing , Zhang Ji , Fu Yun , Zhu Wen , Yu Xiao‐Qi 
Published: May 2012

AbstractTwo novel cationic lipids based on protonated cyclen and steroid (cholesterol or diosgenin) moieties with carbamate linkage have been designed and synthesized for gene delivery. Cationic liposomes were easily prepared from each of these lipids individually or from the mixtures of each cationic lipid and dioleoylphosphatidyl ethanolamine (DOPE). Several studies including dynamic light scattering, gel retardation assay, ethidium bromide intercalation assay, and transmission electron microscopy (TEM) imaging demonstrate that these amphiphilic molecules are able to bind and compact DNA into nanoparticles which may act as nonviral gene delivery agents. Results from in vitro transfection show that in association with (DOPE), two cationic lipids can induce effective gene transfection in HEK 293, A549, and H460 cells. Especially, in tumor cells (A549 and H460), the gene transfection efficiency of two cationic lipids were found to be higher than that of commercially available Lipofectamine 2000. The lipoplexes formed from both cationic lipids were found to have low cytotoxicity in three cell lines even at high N/P ratios.
A simulation study for the distribution law of relative moments of evolution
Authors: Jäntschi Lorentz , Bolboacă Sorana D. , Sestraş Radu E. 
Published: May 2012

AbstractNine selection‐survival strategies were implemented in a genetic algorithm experiment, and differences in terms of evolution were assessed. The moments of evolution (expressed as generation numbers) were recorded in a contingency of three strategies (i.e., proportional, tournament, and deterministic) for two moments (i.e., selection for crossover and mutation and survival for replacement). The experiment was conducted for the first 20,000 generations in 46 independent runs. The relative moments of evolution (where evolution was defined as a significant increase in the determination coefficient relative to the previous generation) when any selection‐survival strategy was used fit a Log‐Pearson type III distribution. Moreover, when distributions were compared to one another, functional relationships were identified between the population parameters, revealing a degeneration of the Log‐Pearson type III distribution in a one‐parametrical distribution that can be assigned to the chosen variable—evolution strategy. The obtained theoretical population distribution allowed comparison of the selection‐survival strategies that were used. © 2012 Wiley Periodicals, Inc. Complexity, 2012.
Tunable synthesis of hierarchical TiO2 spheres consisting of rutile nanowires for dye‐sensitized solar cells and photocatalysis
Authors: Wang Hequan , Yu Xiao , Li Haibo , Du Yu , Xin Ling 
Published: May 2012

AbstractHierarchical TiO2 spheres consisting of rutile nanowires (HTS) are successfully prepared in the bulk solution via a non‐polar solvent/polar solution interfacial syntheses strategy. The effect of reaction temperature on the morphology, size, BET surface area and monodispersion of HTS is studied systematically. Increasing reaction temperature decreases the diameter of spheres in micro‐scale whereas increases the diameter of nanowires in nano‐scale for these HTS. Monodisperse HTS are formed at 230 °C for 20 h, which can suitably be served as light scattering structure for dye‐sensitized solar cell with the additional advantage of rapid electron transport rate. A high efficiency of 8.54% was achieved for the composite DSSC consisting of nanoparticles and monodispersed HTS (synthesized at 230 °C), showing 31.38% improvement compared with that (6.5%) of the DSSCs made from pure P25 nanoparticles at the similar thickness. Furthermore, the photocatalytic performances of HTS for the degradation of methyl orange were also investigated. Contrary to the effect on the performance of DSSC, the HTS synthesized at 150 °C show higher photocatalytic degradation efficiency due to larger BET surface area.
Reactivity of (E)‐4‐Hydroxy‐2‐nonenal with Fluorinated Phenylhydrazines: Towards the Efficient Derivatization of an Elusive Key Biomarker of Lipid Peroxidation
Authors: Matera Riccardo , Gabbanini Simone , Valvassori Alice , Triquigneaux Mathilde , Valgimigli Luca 
Published: May 2012

Abstract4‐Hydroxynonenal (4‐HNE) is a major product of the oxidation of ω‐6‐polyunstaturated lipids and an effector of radical‐mediated oxidative damage, whose analytical determination requires chemical derivatization. In this work, its reactivity with fluorinated phenylhydrazines was explored both under preparative and analytical settings. A five‐step synthesis of 4‐HNE on gram‐scale with an overall yield of 30 % is described. Reaction of 4‐HNE with ortho‐, meta‐, or para‐CF3‐phenylhydrazine, as well as with the 3,5‐di‐CF3, 2,4‐di‐CF3, or pentafluoro analogues, in MeCN with 0.5 mM TFA yields the corresponding hydrazones with rate constants kf of 2.8 ± 0.4, 1.7 ± 0.1, 3.0 ± 0.2, 0.6 ± 0.1, 0.5 ± 0.1, and 3.5 ± 0.5 M–1 s–1, respectively at 298 K. At higher temperatures, the hydrazones undergo intramolecular cyclization to form 1,6‐dihydropyridazines that, depending on the solvent and temperature, may further react with the hydrazine to yield tetrahydropyridazine adducts and their oxidation products. Other reaction products were isolated, depending on the reaction conditions, and the complex reactivity of 4‐HNE with the above nucleophiles is discussed. Due to the good yield and rate of formation of the hydrazone adducts, their stability and favorable UV absorbance, 2‐(trifluoromethyl)phenylhydrazine and 2,3,4,5,6‐pentafluorophenylhydrazine are the most interesting candidates for the development of rapid and efficient analytical derivatizations of 4‐HNE.
Stabilities of Immonium Ions Derived from N‐Heterocyclic Carbenes Probed by Collision‐Induced Dissociation Mass Spectrometry
Authors: Polyakova Svetlana M. , Kunetskiy Roman A. , Schröder Detlef 
Published: May 2012

AbstractWe report efficient methods for the synthesis of both symmetrically and non‐symmetrically substituted bis(imidazol‐2‐yliden)ammonium ions and a new family of bis(imidazol‐2‐ylidene)formamidines. The fragmentation pathways of these cations were studied in detail by electrospray ionization combined with tandem mass spectrometry. Interestingly, in these cations direct C–N bond cleavage leading to loss of alkyl radicals can compete with rearrangement reactions leading to closed‐shell fragments. The experimental results for the major fragmentation channels are compared with those derived from DFT calculations. Inter alia, a novel rearrangement of the cationic species involving specific alkyl migrations between the two imidazole subunits has been found.
Toxicokinetic and toxicodynamic model for diazinon toxicity—mechanistic explanation of differences in the sensitivity of Daphnia magna and Gammarus pulex
Authors: Kretschmann Andreas , Ashauer Roman , Hollender Juliane , Escher Beate I. 
Published: May 2012

Abstract
A mechanistic toxicokinetic and toxicodynamic model for acute toxic effects (immobilization, mortality) of the organothiophosphate insecticide diazinon in Daphnia magna is presented. The model was parameterized using measured external and internal (whole-body) concentrations of diazinon, its toxic metabolite diazoxon, and the inactive metabolite 2-isopropyl-6-methyl-4-pyrimidinol, plus acetylcholinesterase (AChE) activity measured during exposure to diazinon in vivo. The toxicokinetic and toxicodynamic model provides a coherent picture from exposure to the resulting toxic effect on an organism level through internally formed metabolites and the effect on a molecular scale. A very fast reaction of diazoxon with AChE (pseudo first-order inhibition rate constant ki = 3.3 h−1) compared with a slow formation of diazoxon (activation rate constant kact = 0.014 h−1) was responsible for the high sensitivity of D. magna toward diazinon. Recovery of AChE activity from inhibition was slow and rate-determining (99% recovery within 16 d), compared with a fast elimination of diazinon (99% elimination within 17 h). The obtained model parameters were compared with toxicokinetic and toxicodynamic parameters of Gammarus pulex exposed to diazinon from previous work. This comparison revealed that G. pulex is less sensitive because of a six times faster detoxification of diazinon and diazoxon and an approximately 400 times lower rate for damage accrual. These differences overcompensate the two times faster activation of diazinon to diazoxon in G. pulex compared to D. magna. The present study substantiates theoretical considerations that mechanistically based effect models are helpful to explain sensitivity differences among different aquatic invertebrates. Environ. Toxicol. Chem. 2012; 31: 2014–2022. © 2012 SETAC
A new species and some notes on the genus Nonea (Boraginaceae) in Iran
Authors: Falatoury Atiye Nejhad , Pakravan Maneezheh , Tavassoli Akhtar 
Published: May 2012

AbstractThe new species Nonea iranica (Boraginaceae‐Boragineae) is described from central region of Iran. It shows a combination of morphological characteristics concerning root, flower and fruit that distinguishes it from N. caspica and N. polychoroma. The palynological examination supports the results of morphological observations. The doubts about two species of Iran, N. longiflora and N. stenosolen, are discussed. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Expression of olfactory‐type cyclic nucleotide‐gated channels in rat cortical astrocytes
Authors: Podda Maria Vittoria , Leone Lucia , Piacentini Roberto , Cocco Sara , Mezzogori Daniele , D'Ascenzo Marcello , Grassi Claudio 
Published: May 2012

AbstractCyclic nucleotide‐gated (CNG) channels are nonselective cation channels activated by cyclic AMP (cAMP) or cyclic GMP (cGMP). They were originally identified in retinal and olfactory receptors, but evidence has also emerged for their expression in several mammalian brain areas. Because cGMP and cAMP control important aspects of glial cell physiology, we wondered whether CNG channels are expressed in astrocytes, the most functionally relevant glial cells in the CNS. Immunoblot and immunofluorescence experiments demonstrated expression of the CNG channel olfactory‐type A subunit, CNGA2, in cultured rat cortical astrocytes. In patch‐clamp experiments, currents elicited in these cells by voltage ramps from −100 to +100 mV in the presence of the cGMP analogue, dB‐cGMP, were significantly reduced by the CNG channel blockers, L‐cis‐diltiazem (LCD) and Cd2+. The reversal potentials of the LCD‐ and Cd2+‐sensitive currents were more positive than that of K+, as expected for a mixed cation current. Noninactivating, voltage‐independent currents were also elicited by extracellular application of the membrane permeant cGMP analogue, 8‐Br‐cGMP. These effects were blocked by LCD and were mimicked by natriuretic peptide receptor activation and inhibition of phosphodiesterase activity. Voltage‐independent, LCD‐sensitive currents were also elicited by 8‐Br‐cGMP in astrocytes of hippocampal and neocortical brain slices. Immunohistochemistry confirmed a broad distribution of CNG channels in astrocytes of the rat forebrain, midbrain, and hindbrain. These findings suggest that CNG channels are downstream targets of cyclic nucleotides in astrocytes, and they may be involved in the glial‐mediated regulation of CNS functions under physiological and pathological conditions. © 2012 Wiley Periodicals, Inc.
Modulation by pregnenolone sulfate of filtering properties in the hippocampal trisynaptic circuit
Authors: Scullin Chessa S. , Partridge L. Donald 
Published: May 2012

AbstractShort‐term synaptic plasticity alters synaptic efficacy on a timescale that is relevant to encoding information in spike trains. The dynamics of this plasticity, combined with that of the feedback and feedforward contributions of local interneurons, impose frequency‐dependent properties on neuronal networks with implications for nervous system function. The trisynaptic network of the hippocampus is especially well suited to selectively filter components of frequency‐dependent signals that are transmitted from the entorhinal cortex. We measured presynaptic [Ca2+]i in perforant path, mossy fiber, or Schaffer collateral terminals while simultaneously measuring field potentials of principal cells of the dentate, CA3, or CA1 synaptic fields over a range of stimulus frequencies of 2 to 77 Hz. In all three synaptic fields, the average [Ca2+]i during a 500 ms stimulus train rose monotonically with stimulus frequency. The average population spike amplitude during this stimulus train, however, exhibited a non‐linear relationship to frequency that was distinct for each of the three synaptic fields. The dentate synaptic field exhibited the characteristics of a low pass filter, while both CA synaptic fields had bandpass filter characteristics with a gain that was greater than 1 in the passband frequencies. Importantly, alteration of the dynamic properties of this network could significantly impact information processing performed by the hippocampus. Pregnenolone sulfate (PregS), has frequency‐dependent effects on paired‐ and multipulse plasticity in the dentate and CA1 synaptic fields of the hippocampal formation. We investigated the PregS‐dependent modulation of the dynamic properties of transmission by the principal cells of the three hippocampal synaptic fields. Importantly, PregS is capable of altering the pattern separation capabilities that may underlie hippocampal information processing. © 2012 Wiley Periodicals, Inc.
From policy to reality: clinical managers' views of the organizational challenges of primary care reform in Portugal
Authors: Lapão Luís Velez , Dussault Gilles 
Published: May 2012

SUMMARYThe primary healthcare reform in Portugal is based on the development of a new management model and clinical governance framework. The objective is to strengthen primary healthcare services to reduce the inappropriate utilization of secondary and emergency services and to make efficiency gains and to better control costs. New interventions include the introduction of a system of production‐based incentives for family health units. This paper presents an initial assessment of the implementation of the new policies and tries to explain the gap between its expected results and what was observed in the field 5 years later. We used a Strengths, Weaknesses, Opportunities, and Threats analysis conducted in 12 regions, to collect the perceptions of members of Clinical Councils of Health Centers Groups, responsible for the implementation of the reform. The analysis looked at the dimensions of coverage, productivity, technical quality, and service quality. It identifies weaknesses in human resources management (shortages, incentives, team management) and lack of support from central and regional management. There is a perceived gap between the framework for reform as defined by law and the support made available for its implementation, leading to tensions between decision makers, managers, and health professionals. Copyright © 2012 John Wiley & Sons, Ltd.
Multimodal photoacoustic ophthalmoscopy in mouse
Authors: Song Wei , Wei Qing , Feng Liang , Sarthy Vijay , Jiao Shuliang , Liu Xiaorong , Zhang Hao F. 
Published: May 2012

AbstractPhotoacoustic ophthalmoscopy (PAOM) is a novel imaging technology that measures optical absorption in the retina. The capability of PAOM can be further enhanced if it could image mouse eyes, because mouse models are widely used for various retinal diseases. The challenges in achieving high‐quality imaging of mouse retina, however, come from the much smaller eyeball size. Here, we report an optimized imaging system, which integrates PAOM, spectral‐domain optical coherence tomography (SD‐OCT), and autofluorescence‐scanning laser ophthalmoscopy (AF‐SLO), for mouse eyes. Its multimodal capability was demonstrated by imaging transgenic Nrl‐GFP mice that express green fluorescent protein (GFP) in photoreceptors. SD‐OCT provided guidance of optical alignment for PAOM and AF‐SLO, and complementary contrast with high depth‐resolution retinal cross sections. PAOM visualized the retinal vasculature and retinal pigment epithelium melanin, and AF‐SLO measured GFP‐expressing in retinal photoreceptors. The in vivo imaging results were verified by histology and confocal microscopy. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Catch up in bone acquisition in young adult men with late normal puberty
Authors: Darelid Anna , Ohlsson Claes , Nilsson Martin , Kindblom Jenny M , Mellström Dan , Lorentzon Mattias 
Published: May 2012

Abstract
The aim of this study was to investigate the development of bone mineral density (BMD) and bone mineral content (BMC) in relation to peak height velocity (PHV), and to investigate whether late normal puberty was associated with remaining low BMD and BMC in early adulthood in men. In total, 501 men (mean ± SD, 18.9 ± 0.5 years of age at baseline) were included in this 5-year longitudinal study. Areal BMD (aBMD) and BMC, volumetric BMD (vBMD) and cortical bone size were measured using dual-energy X-ray absorptiometry (DXA) and pQCT. Detailed growth and weight charts were used to calculate age at PHV, an objective assessment of pubertal timing. Age at PHV was a strong positive predictor of the increase in aBMD and BMC of the total body (R2 aBMD 11.7%; BMC 4.3%), radius (R2 aBMD 23.5%; BMC 22.3%), and lumbar spine (R2 aBMD 11.9%; BMC 10.5%) between 19 and 24 years (p &lt; 0.001). Subjects were divided into three groups according to age at PHV (early, middle, and late). Men with late puberty gained markedly more in aBMD and BMC at the total body, radius, and lumbar spine, and lost less at the femoral neck (p &lt; 0.001) than men with early puberty. At age 24 years, no significant differences in aBMD or BMC of the lumbar spine, femoral neck, or total body were observed, whereas a deficit of 4.2% in radius aBMD, but not in BMC, was seen for men with late versus early puberty (p &lt; 0.001). pQCT measurements of the radius at follow-up demonstrated no significant differences in bone size, whereas cortical and trabecular vBMD were 0.7% (p &lt; 0.001) and 4.8% (p &lt; 0.05) lower in men with late versus early puberty. In conclusion, our results demonstrate that late puberty in males was associated with a substantial catch up in aBMD and BMC in young adulthood, leaving no deficits of the lumbar spine, femoral neck, or total body at age 24 years. © 2012 American Society for Bone and Mineral Research.
Effect of low-dose calcium supplements on bone loss in perimenopausal and postmenopausal Asian women: A randomized controlled trial
Authors: Nakamura Kazutoshi , Saito Toshiko , Kobayashi Ryosaku , Oshiki Rieko , Kitamura Kaori , Oyama Mari , Narisawa Sachiko , Nashimoto Mitsue , Takahashi Shunsuke , Takachi Ribeka 
Published: May 2012

Abstract
Current standard-dose calcium supplements (eg, 1000 mg/d) may increase the risk for cardiovascular events. Effectiveness of lower-dose supplements in preventing bone loss should thus be considered. This study aimed to assess whether calcium supplements of 500 or 250 mg/d effectively prevent bone loss in perimenopausal and postmenopausal Japanese women. We recruited 450 Japanese women between 50 and 75 years of age. They were randomly assigned to receive 500 mg of calcium (as calcium carbonate), 250 mg of calcium, or placebo daily. Medical examinations conducted three times over a 2-year follow-up period assessed bone mineral density (BMD) of the lumbar spine and femoral neck. One-factor repeated measures ANOVA was used for statistical tests. Subgroup analyses were also conducted. Average total daily calcium intake at baseline for the 418 subjects who underwent follow-up examinations was 493 mg/d. Intention-to-treat analysis showed less dramatic decreases in spinal BMD for the 500-mg/d calcium supplement group compared to the placebo group (1.2% difference over 2 years, p = 0.027). Per-protocol analysis (≥80% compliance) revealed that spinal BMD for the 500-mg/d and 250-mg/d calcium supplement groups decreased less than the placebo group (1.6%, p = 0.010 and 1.0%, p = 0.078, respectively), and that femoral neck BMD for the 500-mg/d calcium supplement group decreased less relative to the placebo group (1.0%, p = 0.077). A low-dose calcium supplement of 500 mg/d can effectively slow lumbar spine bone loss in perimenopausal and postmenopausal women with habitually low calcium intake, but its effect on the femoral neck is less certain. Calcium supplementation dosage should thus be reassessed. (Clinical Trials Registry number: UMIN000001176). © 2012 American Society for Bone and Mineral Research.
Hematopoietic progenitor constituents and adherent cell progenitor morphology isolated from black‐rumped agouti (Dasyprocta prymnolopha, Wagler 1831) bone marrow
Authors: Da Rocha Andressa Rego , Alves Flávio Ribeiro , Neto NapoleãO Martins Argôlo , Dos Santos Luciano Fonseca , De Almeida Hatawa Melo , De Carvalho Yulla Klinger Pereira , Bezerra Dayseanny De Oliveira , Ferraz Maíra Soares , Pessoa Gerson Tavares , De Carvalho Maria Acelina Martins 
Published: May 2012

AbstractStem cells are present in the adult tissues of most diverse species. Bone marrow is recognized to be the most exploited site to obtain stem cells and cell progenitors. The objective of the present study was to characterize hematopoietic progenitor (HP) morphology and analyze the performance of adherent cell progenitors (ACPs) cultivated in vitro from black‐rumped agouti bone marrow (Dasyprocta prymnolopha). Bone marrow aspirates were obtained from tibia crest and used to prepare histological slides and identify cell morphology. Cells were also scattered on culture plates for later isolation, expansion, and quantification. Smears obtained from bone marrow demonstrated HPs at different stages of maturity. In culture, these cells showed fibroblastoid morphology and a strong tendency to form colonies, demonstrated by the presence of cell aggregates, cytoplasmic elongations lying side by side. An 80% cell confluence was observed at 18 days in culture and progressive reduction in the percentage of nonadherent mononuclear cells. After eight passes, a mean cell viability of 96.07% was observed, from a pool of 1.6 × 107 cells (ACP). Thirteen 25‐cm2 culture bottles were trypsinized, resuspended in freezing medium, stored in 14 criotubes at a concentration of 1 × 106 cells per milliliter, and placed in liquid nitrogen at −196°C. Agouti bone marrow demonstrated high plasticity, moreover different HP lines, and a population of adherent cells demonstrated morphology similar to mesenchymal stem cells in culture. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.