bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimized expression of dual reporter genes in transient transfection of purifiedToxoplasma gondiiusing different promoters
Authors: Hao Yongxin , Yang Jianmin , Li Xuelian , Ding Jun , Zhang Wei , Liu Qun 
Published: April 2012

Fluorescent protein and luciferase genes are valuable reporter genes and have been widely used for noninvasive monitoring of gene expression in living tissues and cells. We tested expression of the dual reporter genes in transient transfection of purified Toxoplasma gondii tachyzoites. Two copies of the enhanced yellow fluorescent protein (EYFP) gene were put under the control of 3 representative T. gondii promoters (GRA1, SAG1, and DHFR). Fluorescence from each EYFP reporter was significantly higher than that from a green fluorescent protein (GFP) reporter. The GRA1-EYFP reporter gave the highest fluorescence. Although both fluorescence and luciferase were expressed in the dual reporter system, the luciferase reporter was more efficient than either the EYFP or GFP reporters, and it required fewer parasites to be successfully used.
Secular Trends in Ischemic Stroke Characteristics in a Rapidly Developed Country
Authors: Jung Keun-Hwa , Lee Seung-Hoon , Kim Beom Joon , Yu Kyung-Ho , Hong Keun-Sik , Lee Byung-Chul , Roh Jae-Kyu ,   Korean Stroke Registry Study Group
Published: April 2012

Background—
A dynamic change in industry, lifestyle, and healthcare structure brings a corresponding change in disease patterns. Limited data exist with respect to secular trends in stroke epidemiology in Korea, a rapidly developed country.

Methods and Results—

We analyzed individual patient data registered the Korean Stroke Registry, a nationwide hospital-based stroke database, between January 2002 and November 2010. Mortality data were obtained from a national death certificate system. Linear or logistic regression analyses were performed to assess secular trends. A total of 46 098 patients were included in this study. Mean±SD age was 66.1±12.3 years, and 57.6% of the patients were men. Over the 9-year period, patient ages steadily increased by 0.24 year annually (
P
<0.001). Risk factor proportions of hypertension, diabetes, smoking, and prior stroke declined slightly (
P
<0.05 for all). However, dyslipidemia frequency showed a complex pattern of an initial decline and then an increase. For relative proportions of subtypes, cardioembolism increased, small vessel occlusion decreased, and large artery atherosclerosis remained stable. Still, intracranial stenosis overwhelms extracranial stenosis, but extracranial stenosis is on the rise. Arrival within 3 hours increased from 20% to 29%, and reperfusion therapy increased from 5.3% to 7.0%. Age-adjusted all-cause mortality did not decrease at 30 days but decreased at 1 year over time.

Conclusions—
During the first decade of 21st century, stroke characteristics in Korea changed, likely because of increased lifespan, westernized lifestyle, and improved public awareness. Stroke experts need to cope with these distinguishing trends to establish a better strategy for prevention and acute therapy.
Potency, selectivity and prolonged binding of saxagliptin to DPP4: maintenance of DPP4 inhibition by saxagliptin in vitro and ex vivo when compared to a rapidly-dissociating DPP4 inhibitor
Authors: Wang Aiying , Dorso Charles , Kopcho Lisa , Locke Gregory , Langish Robert , Harstad Eric , Shipkova Petia , Marcinkeviciene Jovita , Hamann Lawrence , Kirby Mark S 
Published: April 2012

Abstract

Background
Dipeptidylpeptidase 4 (DPP4) inhibitors have clinical benefit in patients with type 2 diabetes mellitus by increasing levels of glucose-lowering incretin hormones, such as glucagon-like peptide -1 (GLP-1), a peptide with a short half life that is secreted for approximately 1 hour following a meal. Since drugs with prolonged binding to their target have been shown to maximize pharmacodynamic effects while minimizing drug levels, we developed a time-dependent inhibitor that has a half-life for dissociation from DPP4 close to the duration of the first phase of GLP-1 release.

Results
Saxagliptin and its active metabolite (5-hydroxysaxagliptin) are potent inhibitors of human DPP4 with prolonged dissociation from its active site (Ki = 1.3 nM and 2.6 nM, t1/2 = 50 and 23 minutes respectively at 37°C). In comparison, both vildagliptin (3.5 minutes) and sitagliptin ( < 2 minutes) rapidly dissociated from DPP4 at 37°C. Saxagliptin and 5-hydroxysaxagliptin are selective for inhibition of DPP4 versus other DPP family members and a large panel of other proteases, and have similar potency and efficacy across multiple species.
Inhibition of plasma DPP activity is used as a biomarker in animal models and clinical trials. However, most DPP4 inhibitors are competitive with substrate and rapidly dissociate from DPP4; therefore, the type of substrate, volume of addition and final concentration of substrate in these assays can change measured inhibition. We show that unlike a rapidly dissociating DPP4 inhibitor, inhibition of plasma DPP activity by saxagliptin and 5-hydroxysaxagliptin in an ex vivo assay was not dependent on substrate concentration when substrate was added rapidly because saxagliptin and 5-hydroxysaxagliptin dissociate slowly from DPP4, once bound. We also show that substrate concentration was important for rapidly dissociating DPP4 inhibitors.

Conclusions
Saxagliptin and its active metabolite are potent, selective inhibitors of DPP4, with prolonged dissociation from its active site. They also demonstrate prolonged inhibition of plasma DPP4 ex vivo in animal models, which implies that saxagliptin and 5-hydroxysaxagliptin would continue to inhibit DPP4 during rapid increases in substrates in vivo.
Heightened expression of MICA enhances the cytotoxicity of NK cells or CD8+T cells to human corneal epithelium in vitro
Authors: Hong Jiaxu , Qiu Ting , Qian Tingting , Li Gang , Yu Xiaobo , Chen Junyi , Le Qihua , Sun Xinghuai , Xu Jianjiang 
Published: April 2012

Abstract

Background
Major-histocompatibility-complex class I-related chain A (MICA) antigens are the ligands of NKG2D, which is an activating or coactivating receptor expressed on human NK cells and CD8+T cells. We sought to determine whether MICA expression in human corneal epithelium (HCE) could affect the cytotoxicity mediated by NK cells or CD8+T cells.

Methods
Cell cultures of HCE were harvested from human donor eyes. Flow cytometric analysis and ELISA was performed to determine the levels of MICA expression on HCE. Then, HCE was transfected with a lentivirus vector expressing MICA and GFP. Flow cytometric analysis, RT-PCR, western blot and ELISA were performed to check the levels of MICA expression. For cytotoxicity testing, allogeneic NK cells and CD8+T cells were isolated from peripheral blood mononuclear cells of healthy volunteers by magnetic cell sorting. The cytolytic activity of NK cells and CD8+T cells was assessed against MICA-transfected HCE (NK cells: E:T ratio = 3:1; CD8+T cells: E:T ratio = 10:1) using the nonradioactive cytotoxicity detection kit lactate deshydrogenase.

Results
Surface expression of MICA on corneal epithelium was identified at a low level. A cell line of stable human MICA-transfected corneal epithelium was successfully established. Heightened expression of MICA on HCE was found to promote the cytotoxicity mediated by NK cells or CD8+T cells, which could be blocked by an anti-MICA antibody.

Conclusion
MICA molecules may contribute to cytotoxic responses mediated by activated immune effector cells in corneal epithelium immunity.
Adaptive matching pursuit with constrained total least squares
Authors: Huang Tianyao , Liu Yimin , Meng Huadong , Wang Xiqin 
Published: April 2012

Abstract
Compressive sensing (CS) can effectively recover a signal when it is sparse in some discrete atoms. However, in some applications, signals are sparse in a continuous parameter space, e.g., frequency space, rather than discrete atoms. Usually, we divide the continuous parameter into finite discrete grid points and build a dictionary from these grid points. However, the actual targets may not exactly lie on the grid points no matter how densely the parameter is grided, which introduces mismatch between the predefined dictionary and the actual one. In this article, a novel method, namely adaptive matching pursuit with constrained total least squares (AMP-CTLS), is proposed to find actual atoms even if they are not included in the initial dictionary. In AMP-CTLS, the grid and the dictionary are adaptively updated to better agree with measurements. The convergence of the algorithm is discussed, and numerical experiments demonstrate the advantages of AMP-CTLS.
A novel fluorescent assay for sucrose transporters
Authors: Gora Peter J , Reinders Anke , Ward John M 
Published: April 2012

Abstract

Background
We have developed a novel assay based on the ability of type I sucrose uptake transporters (SUTs) to transport the fluorescent coumarin β-glucoside, esculin. Budding yeast (Saccharomyces cerevisiae) is routinely used for the heterologous expression of SUTs and does not take up esculin.

Results
When type I sucrose transporters StSUT1 from potato or AtSUC2 from Arabidopsis were expressed in yeast, the cells were able to take up esculin and became brightly fluorescent. We tested a variety of incubation times, esculin concentrations, and buffer pH values and found that for these transporters, a 1 hr incubation at 0.1 to 1 mM esculin at pH 4.0 produced fluorescent cells that were easily distinguished from vector controls. Esculin uptake was assayed by several methods including fluorescence microscopy, spectrofluorometry and fluorescence-activiated cell sorting (FACS). Expression of the type II sucrose transporter OsSUT1 from rice did not result in increased esculin uptake under any conditions tested. Results were reproduced successfully in two distinct yeast strains, SEY6210 (an invertase mutant) and BY4742.

Conclusions
The esculin uptake assay is rapid and sensitive and should be generally useful for preliminary tests of sucrose transporter function by heterologous expression in yeast. This assay is also suitable for selection of yeast showing esculin uptake activity using FACS.
Synthesis of Hyperbranched Azo-polymer-grafted Graphene Oxide Hybrid
Authors: Wang Yang , Wei Renbo , He Yaning , Wang Xiaogong 
Published: April 2012

Abstract
Hyperbranched azo-polymer-grafted graphene oxide (GO) hybrid was synthesized. Epoxy-based precursor polymer was first covalently attached to GO through an ester linkage. Then the hyperbranched azo-polymer-grafted graphene oxide hybrid can be obtained by azo-coupling reaction between the epoxy-based precursor-polymer-functionalized GO and hyperbranched diazonium salts under extremely mild conditions.
Electrochemical Impedance Analysis on Degradation of Commercially Available Lithium Ion Battery during Charge–Discharge Cycling
Authors: Mukoyama Daikichi , Momma Toshiyuki , Nara Hiroki , Osaka Tetsuya 
Published: April 2012

Abstract
The degradation of the commercial Li ion battery was analyzed by electrochemical impedance spectroscopy, where our previous proposed equivalent circuit was applied. The degradation with the cycling was clearly explained by the main parameters of capacitive and resistive components, i.e., it responded until 300 cycles to the decrease in capacitive component, while after 300 to 550 cycles to the increase in resistive component.
Continuous Fabrication of Novel Polyimide Nanoparticles Confining Highly Dispersed Gold Nanoparticles by a Multistep Microfluidic Reaction System and Their Catalytic Application
Authors: Ishizaka Takayuki , Ishigaki Atsushi , Chatterjee Maya , Suzuki Akira , Suzuki Toshishige M , Kawanami Hajime 
Published: April 2012

Abstract
Novel polyimide nanoparticles confining maximum 12.5 wt % of highly dispersed Au nanoparticles (size: 5.6 nm) were continuously fabricated by using a multistep microfluidic reaction system; the particles show good activity for the hydrogenation in scCO2 with excellent yields and selectivity without leaching and agglomeration of Au nanoparticles.
Supramolecular Chirality Measurement of an Optically Anomalous Single Crystal
Authors: Harada Takunori , Asano Natsuyo , Tajima Nobuo , Moriyama Hiroshi 
Published: April 2012

Abstract
The compound 1,8-dihydroxyanthraquinone (DHA) forms chiral crystals composed of several distinct homogeneous regions giving triclinic symmetry in an apparently tetragonal unit cell. True chirality measurement of an optically anomalous DHA crystal was achieved for the first time using a universal chiroptical spectrophotometer in the UV–vis wavelength range.
Oral Antidiabetic Drugs and Regression from Prediabetes to Normoglycemia: A Meta-Analysis
Authors: Phung Olivia J , Baker William L , Tongbram Vanita , Bhardwaj Adarsh , Coleman Craig I 
Published: April 2012

Background: Impaired glucose tolerance, impaired fasting glucose, and elevated hemoglobin A1c are intermediate stages, considered prediabetes, a precursor to overt type 2 diabetes mellitus. Prediabetes is associated with increased risk for cardiovascular disease, independent of diabetes development. Data have shown that various oral antidiabetic drugs can help people regress from prediabetes to normoglycemia. Objective: To evaluate the efficacy of oral antidiabetic drugs in promoting regression from prediabetes to normoglycemia. Methods: MEDLINE (1950–November 2011), EMBASE (1990–November 2011), and Cochrane Central Register of Controlled Trials (indexed September 2011) were systematically searched. A manual search of references from reports of clinical trials and review articles was performed to identify additional relevant studies. Randomized controlled trials 12 weeks or more in duration evaluating any of the oral antidiabetic drugs and studying regression from prediabetes to normoglycemia were included. A random-effects model was used to calculate pooled odds ratios with 95% confidence intervals. Results: Thirteen studies (N = 11,600 participants) were included in the metaanalysis. Use of oral antidiabetic drugs in prediabetic patients was shown to double the odds of achieving normoglycemia compared to controls (OR 2.03, 95% CI 1.54 to 2.67). When individual classes of oral antidiabetic drugs were evaluated, use of thiazolidinediones (OR 2.33, 95% CI 1.93 to 2.81) and α-glucosidase inhibitors (OR 2.02, 95% CI 1.26 to 3.24) was associated with significantly increased odds. However, biguanides (OR 2.04) and sulfonylureas (OR 1.84) failed to reach statistical significance (p = 0.06 and p = 0.39, respectively). Conclusions: In patients with prediabetes, oral antidiabetic drugs were associated with increased odds of regression to normoglycemia versus placebo/control. Only thiazolidinediones and α-glucosidase inhibitors provided a statistically significant increase in odds of regressing to normoglycemia.
Is Statin-Associated Cognitive Impairment Clinically Relevant? A Narrative Review and Clinical Recommendations
Authors: Rojas-Fernandez Carlos H , Cameron Jean-Christy F 
Published: April 2012

Objective: To explore the impact of statin use on cognition. Data Sources: A literature search was performed using MEDLINE (1950-November 2011), EMBASE (1980-November 2011), and the Cochrane Library (1960-November 2011) using the search terms “cognition/drug effects,” “delirium, dementia, amnestic, cognitive disorders/chemically induced,” “memory disorders/chemically induced,” “hydroxymethylglutaryl-CoA reductase inhibitors/adverse effects,” and “hydroxymethylglutaryl-CoA reductase inhibitors.” A bibliographic search on included references was also conducted. Study Selection and Data Extraction: Studies were included for analysis if they were conducted in humans and examined the impact of statin use on cognition as either a primary or secondary endpoint; case reports and case series were also included for analysis. Data Synthesis: Reports of statin-associated cognitive impairment were found primarily in observational studies (eg, case reports/series). One randomized controlled trial demonstrated that simvastatin impaired some measures of cognition compared to placebo. Conversely, in the majority of randomized controlled trials and observational studies, statins were found to have either a neutral or beneficial effect on cognition. Preliminary data suggest that statins that are less lipophilic (ie, pravastatin and rosuvastatin) may be less likely to contribute to cognitive impairment due to limited penetration across the blood-brain barrier. These drugs would be a logical alternative in cases where cognitive impairment secondary to another statin is suspected. Conclusions: Despite several reports of statin-associated cognitive impairment, this adverse effect remains a rare occurrence among the totality of the literature. If statin-associated cognitive impairment is suspected, a trial discontinuation can reveal a temporal relationship. Switching from lipophilic to hydrophilic statins may resolve cognitive impairment. The vascular benefits and putative cognitive benefits outweigh the risk of cognitive impairment associated with statin use; therefore, the current evidence does not support changing practice with respect to statin use, given this adverse effect.
Low-Temperature Hydrothermal Metamorphic Mineralization of Island-Arc Volcanics, South Apuseni Mountains, Romania
Authors: Miron George Dan , Neuhoff Philip S. , Amthauer Georg 
Published: April 2012

AbstractThe island-arc volcanics situated in the eastern part of the Căpîlnaş-Techereu nappe (South Apuseni Mountains, Romania) were studied to evaluate the temperature, fluid properties, and mineral chemistry during low-temperature metamorphism. Detailed observations of metamorphic mineral assemblages were conducted using powder X-ray diffraction and electron microprobe. The metamorphism involved albitization of plagioclase feldspar and the formation of mafic phyllosilicates, zeolites, and other hydrous Ca-Al-silicate minerals. Mafic phyllosilicates consisted of transitional dioctahedral-trioctahedral smectites, mixed-layer chlorite-smectite (C/S, 6–96% chlorite), and discrete chlorite. The zeolites were analcime, stilbite ± stellerite, heulandite, laumontite, epistilbite, and mordenite. Also present, as secondary minerals filling amygdales and veins, are prehnite, pumpellyite, and secondary amphibole. Two mineral assemblages were identified which provide important information about metamorphic conditions (temperature, reaction progress, and fluid properties): (1) heulandite + analcime + quartz; and (2) laumontite + albite + quartz + prehnite + pumpellyite ± amphibole. The types of and relations between minerals in the first assemblage suggest the occurrence of low-temperature hydrothermal metamorphism in the zeolite facies at ~125°C, whereas the second assemblage was metamorphosed at 200°C. The composition and variability of the mineral assemblages in the study area suggest that, due to slow reaction rates, the low-temperature transformations and mineral assemblages were influenced not only by temperature but also by local rock composition, fluid-rock ratio, and fluid chemistry.
Response Surface Optimization for Activation of Bentonite Using Microwave Irradiation
Authors: Petrović Srdjan , Rožić Ljiljana , Vuković Zorica , Novaković Tatjana , Stanisavljev Dragomir 
Published: April 2012

AbstractMicrowave irradiation as a means for heating bentonites during acid activation has been investigated in the past but it has never been optimized for industrial applications. The purpose of this study was to apply a factorial 23 experimental design to a Serbian bentonite in order to determine the influence of microwave heating on the acid-activation process. The effect of acid activation under microwave irradiation on the textural and structural properties of bentonite was studied as a model reaction. A mathematical, second-order response surface model (RSM) was developed with a central composite design that incorporated the relationships among various process parameters (time, acid concentration, and microwave heating power) and the selected process response of specific surface area of the bentonite. The ranges of values for the process parameters chosen were: time, 5–21 min; acid concentration, 2–7 M; and microwave heating power, 63–172 W. The effect of individual variables and their interaction effects on the textural and structural properties of the bentonite were determined. Statistical analysis showed that the duration of microwave irradiation was less significant than the other two factors. The model showed that increasing the time and acid concentration improved the textural properties of bentonites, resulting in increased specific surface area. This model is useful for setting an optimum value of the activation parameters for achieving the maximum specific surface area. An optimum specific surface area of 142 m2g−1 was achieved with an acid concentration of 5.2 M, activation time of 7.4 min, and microwave power of 117 W.
Mangling practices: Writing reflections
Authors: Jefferies Janis 
Published: April 2012

The idea of the practitioner as researcher is everywhere. So is the idea of reflective practice. These ideas … are now so hackneyed and commodified that they have almost come to mean all things to all people. […] A spectator approach to action research is widely practised
in education and corporate settings, especially by those who are positioned as the providers and supporters of practitioners’ research. Self-styled elites preside over others doing their action research, and make judgements using normative criteria about what progress has been made and
how it should be judged. (McNiff, 2002a, 6)
The notion of ‘auto-ethnography’ makes explicit a commitment to a self-reflexive way of knowing and straddles a wide range of cultural (and increasingly) scientific disciplines and interests as well as encompassing a variety of theoretical
and methodological approaches. In practical terms, a journal, diary, field notes, blog is a means by which one records a ‘feel’ for the practice-based work whether through individually situated work or in collaboration with others. This article muses and reflects on what this process
might mean and what its impact could be on the future of practice-based work.
Henson and Rubel's theorem for Zilber's pseudoexponentiation
Authors: Ahuva C. Shkop  
Published: April 2012

AbstractIn 1984, Henson and Rubel [2] proved the following theorem: If p(x1,…, xn) is an exponential polynomial with coefficients in ℂ with no zeroes in ℂ, then p(x1,…, xn) = eg(x1,…, xn) where g(x1,…, xn) is some exponential polynomial over C. In this paper, I will prove the analog of this theorem for Zilber's Pseudoexponential fields directly from the axioms. Furthermore, this proof relies only on the existential closedness axiom without any reference to Schanuel's conjecture.
Woodin's axiom (*), bounded forcing axioms, and precipitous ideals on ω1
Authors: Claverie Benjamin , Schindler Ralf 
Published: April 2012

AbstractIf the Bounded Proper Forcing Axiom BPFA holds, then Mouse Reflection holds at ℵ2 with respect to all mouse operators up to the level of Woodin cardinals in the next ZFC-model. This yields that if Woodin's ℙmax axiom (*) holds, then BPFA implies that V is closed under the “Woodin-in-the-next-ZFC-model” operator. We also discuss stronger Mouse Reflection principles which we show to follow from strengthenings of BPFA, and we discuss the theory BPFA plus “NSω1 is precipitous” and strengthenings thereof. Along the way, we answer a question of Baumgartner and Taylor, [2, Question 6.11].