bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous quantification of three major triterpenoids in radix asteris by high‐performance liquid chromatography with evaporative light scattering detection
Authors: Tian Yaping , Wang Qiao , Wang Yu , Zhang Xiaowei , Sheng Xiaona , Qi Haitao , Zheng Xuguang , Zhang Lantong 
Published: March 2009

AbstractIntroductionRadix asteris, with triterpenoids as its main pharmacological effective compounds, has been widely used for moistening the lung, dispersing phlegm and relieving cough. Quantification of the triterpenoids is important for the quality control of Radix asteris.ObjectiveTo establish a high‐performance liquid chromatography method with evaporative light scattering detection for simultaneous determination of three major triterpenoids, shionone, friedelin and epi‐friedelinol, in Radix asteris.MethodologyThe optimal chromatographic conditions were achieved on an RP18column with gradient elution by acetonitrile and 0.05% acetic acid in 22 min with ELSD set at an evaporating temperature of 40°C. Validation of the method included tests of linearity, sensitivity, precision, repeatability, stability and accuracy.ResultsAll calibration curves showed good linear regression (r2 > 0.9991) within test ranges. The established method showed good precision and accuracy with overall intra‐day and inter‐day variations of 1.61–2.97 and 1.74–2.42%, respectively, and overall recoveries of 97.35–101.13% for the three compounds analysed.ConclusionThe method developed was successfully applied to quantify the main triterpenoids in 14 Radix asteris samples. Copyright © 2009 John Wiley & Sons, Ltd.
Performance of first‐trimester combined screening for trisomy 13 and 18 with the double test taken at a gestational age of 8 + 0 to 13 + 6
Authors: Kirkegaard Ida , Petersen Olav Bjørn , Uldbjerg Niels , Tørring Niels 
Published: March 2009

AbstractObjectiveTo evaluate the performance of the combined test for first‐trimester screening for trisomy 18 and 13, when the double test is scheduled weeks before the nuchal translucency scanning.MethodsThe study included all 40 cases of trisomy 18 and 13 from April 2004 to October 2008 in a screening programme, where the double test was measured in gestational weeks 8 + 0 to 13 + 6 and the nuchal translucency in weeks 11 + 2 to 13 + 6.ResultsTwenty‐eight among the 40 cases had complete information on all variables in the first‐trimester screening test. Among 19 cases having the double test taken before 10 + 0 weeks, 10 cases were detected (detection rate (DR) = 53%) and among 9 cases having the double test taken after 10 + 0 weeks, 6 cases were detected (DR 67%). There was no significant difference in the DRs (p = 0.48). A total of 29 cases were detected at the first‐trimester screening, resulting in an overall DR for trisomy 18 and 13 at 73%.ConclusionThis study showed no significant differences in the trisomy 18/13 DRs when grouped according to having the double test taken before or after 10 + 0 weeks. The DR was 73% at the first‐trimester screening. Copyright © 2009 John Wiley & Sons, Ltd.
Adherence to diagnostic guidelines and quality indicators in asthma and COPD in Swedish primary care
Authors: Weidinger Paolina , Nilsson J. Lars G. , Lindblad Ulf 
Published: March 2009

AbstractPurposeTo study the clinical evaluation and treatment of patients with asthma and COPD in primary care in Sweden, with a focus on adherence to recommended guidelines and quality indicators.MethodsAll visits at health care centres in Skaraborg, Sweden, are documented in computerized medical records constituting the Skaraborg Primary Care Database (SPCD). In a register‐based retrospective observational study, all patients diagnosed with asthma or COPD during 2000–2005 (n = 12 328) were identified. In a 5% random sample (n = 623), information on performed investigations at initial visits and at follow‐up during 2004–2005 was collected. Compliance with procedures as recommended by national guidelines was used for quality assessment.ResultsAmong 499 patients with asthma, 167 (33%) were investigated with spirometry or Peak Expiratory Flow (PEF) during initial visits in agreement with guidelines. Correspondingly, 40 out of 124 patients with COPD (32%) were investigated with spirometry. During follow‐up, evaluation in agreement with guidelines was performed in 130 (60%) of patients with asthma and in 35 patients out of 77 (45%) with COPD. Prescribing of ICS reached quality target, still every second patient made an acute visit during follow‐up.ConclusionAdherence to recommended guidelines in asthma/COPD was low. Acute visits were common and despite the prescribing of ICS according to recommendations, patients still seem uncontrolled in their disease. There is a need for quality improvement in the clinical evaluation and treatment of patients with asthma and COPD. Copyright © 2009 John Wiley & Sons, Ltd.
Creating microstructures on silicon wafers using UV‐crosslinked polystyrene thin films
Authors: Knudsen Daniel , Harnish Bernadette , Toth Ramona , Yan Mingdi 
Published: March 2009

AbstractWe report that UV‐crosslinked polystyrene (PS) thin films can be used as an inexpensive wet chemical etch resist to create microstructures on silicon wafers. When spin‐coated PS films were irradiated, the polymer undergoes UV‐induced crosslinking. Patterned PS films were successfully used as the protective layer withstanding chemical etching with the buffered HF solution. Removal of the polymer films by sonicating in water generated microstructures in silicon wafers. This simple and environmentally friendly procedure employs inexpensive commodity polymer and eliminates the use of organic solvents and harsh conditions in the subsequent development process. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Profile of native N‐linked glycan structures from human serum using high performance liquid chromatography on a microfluidic chip and time‐of‐flight mass spectrometry
Authors: Chu Caroline S. , Niñonuevo Milady R. , Clowers Brian H. , Perkins Patrick D. , An Hyun Joo , Yin Hongfeng , Killeen Kevin , Miyamoto Suzanne , Grimm Rudolf , Lebrilla Carlito B. 
Published: March 2009

AbstractProtein glycosylation involves the addition of monosaccharides in a stepwise process requiring no glycan template. Therefore, identifying the numerous glycoforms, including isomers, can help elucidate the biological function(s) of particular glycans. A method to assess the diversity of the N‐linked oligosaccharides released from human serum without derivatization has been developed using on‐line nanoLC and high resolution TOF MS. The N‐linked oligosaccharides were analyzed with MALDI FT‐ICR MS and microchip LC MS (HPLC–Chip/TOF MS). Two microfluidic chips were employed, the glycan chip (40 nL enrichment column, 43×0.075 mm2 i.d. analytical column) and the high capacity chip (160 nL enrichment column, 140×0.075 mm2 i.d. analytical column), both with graphitized carbon as the stationary phase. Both chips offered good sensitivity and reproducibility in separating a heterogeneous mixture of neutral and anionic oligosaccharides between injections. Increasing the length and volume of the enrichment and the analytical columns improved resolution of the peaks. Complex type N‐linked oligosaccharides were the most abundant oligosaccharides in human serum accounting for ∼96% of the total glycans identified, while hybrid and high mannose type oligosaccharides comprise the remaining ∼4%.
Identification of proteins of Neisseria meningitidis induced under iron‐limiting conditions using the isobaric tandem mass tag (TMT) labeling approach
Authors: van Ulsen Peter , Kuhn Karsten , Prinz Thorsten , Legner Harald , Schmid Peter , Baumann Christian , Tommassen Jan 
Published: March 2009

AbstractIsobaric labeling reagents such as Tandem Mass Tags (TMT®) enable the genome‐wide quantification of protein expression levels under different conditions using a gel‐free MS/MS‐based approach. Here, we applied a TMTduplex approach with two isobaric tags to study the response of the human pathogen Neisseria meningitidis to deprivation of iron, a condition met in the human body. In total, 609 proteins were identified in samples of three independent growth experiments, in which we compared cultures grown in the presence and absence of iron. Expression of 35 proteins was found to be induced or repressed under iron‐limiting conditions, including 11 proteins whose ORFs were not previously identified in DNA array studies as being regulated by iron availability at the transcriptional level. These 11 proteins include proteins likely involved in iron metabolism.
Subcellular proteomics of Trypanosoma cruzi reservosomes
Authors: Sant'Anna Celso , Nakayasu Ernesto S. , Pereira Miria G. , Lourenço Daniela , de Souza Wanderley , Almeida Igor C. , Cunha‐e‐Silva Narcisa L. 
Published: March 2009

AbstractReservosomes are the endpoint of the endocytic pathway in Trypanosoma cruzi epimastigotes. These organelles have the particular ability to concentrate proteins and lipids obtained from medium together with the main proteolytic enzymes originated from the secretory pathway, being at the same time a storage organelle and the main site of protein degradation. Subcellular proteomics have been extensively used for profiling organelles in different cell types. Here, we combine cell fractionation and LC‐MS/MS analysis to identify reservosome‐resident proteins. Starting from a purified reservosome fraction, we established a protocol to isolate reservosome membranes. Transmission electron microscopy was applied to confirm the purity of the fractions. To achieve a better coverage of identified proteins we analyzed the fractions separately and combined the results. LC‐MS/MS analysis identified in total 709 T. cruzi‐specific proteins; of these, 456 had predicted function and 253 were classified as hypothetical proteins. We could confirm the presence of most of the proteins validated by previous work and identify new proteins from different classes such as enzymes, proton pumps, transport proteins, and others. The definition of the reservosome protein profile is a good tool to assess their molecular signature, identify molecular markers, and understand their relationship with different organelles.
Contribution of individual histidines to the global stability of human prolactin
Authors: Keeler Camille , Tettamanzi M. Cristina , Meshack Syrus , Hodsdon Michael E. 
Published: March 2009

AbstractA member of the family of hematopoietic cytokines human prolactin (hPRL) is a 23k kDa polypeptide hormone, which displays pH dependence in its structural and functional properties. The binding affinity of hPRL for the extracellular domain of its receptor decreases 500‐fold over the relatively narrow, physiologic pH range from 8 to 6; whereas, the affinity of human growth hormone (hGH), its closest evolutionary cousin, does not. Similarly, the structural stability of hPRL decreases from 7.6 to 5.6 kcal/mol from pH 8 to 6, respectively, whereas the stability of hGH is slightly increased over this same pH range. hPRL contains nine histidines, compared with hGH's three, and they are likely responsible for hPRL's pH‐dependent behavior. We have systematically mutated each of hPRL's histidines to alanine and measured the effect on pH‐dependent global stability. Surprisingly, a vast majority of these mutations stabilize the native protein, by as much as 2–3 kcal/mol. Changes in the overall pH dependence to hPRL global stability can be rationalized according to the predominant structural interactions of individual histidines in the hPRL tertiary structure. Using double mutant cycles, we detect large interaction free energies within a cluster of nearby histidines, which are both stabilizing and destabilizing to the native state. Finally, by comparing the structural locations of hPRL's nine histidines with their homologous residues in hGH, we speculate on the evolutionary role of replacing structurally stabilizing residues with histidine to introduce pH dependence to cytokine function.
Nanoscale elongating control of the self‐assembled protein filament with the cysteine‐introduced building blocks
Authors: Usui Kengo , Maki Tei , Ito Fuyu , Suenaga Atsushi , Kidoaki Satoru , Itoh Masayoshi , Taiji Makoto , Matsuda Takehisa , Hayashizaki Yoshihide , Suzuki Harukazu 
Published: March 2009

AbstractSelf‐assembly of artificially designed proteins is extremely desirable for nanomaterials. Here we show a novel strategy for the creation of self‐assembling proteins, named “Nanolego.” Nanolego consists of “structural elements” of a structurally stable symmetrical homo‐oligomeric protein and “binding elements,” which are multiple heterointeraction proteins with relatively weak affinity. We have established two key technologies for Nanolego, a stabilization method and a method for terminating the self‐assembly process. The stabilization method is mediated by disulfide bonds between Cysteine‐residues incorporated into the binding elements, and the termination method uses “capping Nanolegos,” in which some of the binding elements in the Nanolego are absent for the self‐assembled ends. With these technologies, we successfully constructed timing‐controlled and size‐regulated filament‐shape complexes via Nanolego self‐assembly. The Nanolego concept and these technologies should pave the way for regulated nanoarchitecture using designed proteins.
Activation of the West Nile virus NS3 protease: Molecular dynamics evidence for a conformational selection mechanism
Authors: Ekonomiuk Dariusz , Caflisch Amedeo 
Published: March 2009

AbstractThe flaviviral nonstructural 3 protease (NS3pro) is essential for virus replication and is therefore a pharmaceutically relevant target to fight Dengue and West Nile virus (WNV). NS3pro is a chymotrypsin‐like serine protease which requires a polypeptide cofactor (NS2B) for activation. Recent X‐ray crystallography studies have led to the suggestion that the substrate binds to the two‐component NS2B‐NS3pro enzyme by an induced‐fit mechanism. Here, multiple explicit water molecular dynamics simulations of the WNV NS2B‐NS3pro enzyme show that the active conformation of the NS2B cofactor (in which its β‐loop is part of the substrate binding site) is stable over a 50‐ns time scale even in the absence of the inhibitor. The partial and reversible opening of the NSB2 β‐loop and its correlated motion with an adjacent NS3pro loop, both observed in the simulations started from the active conformation, are likely to facilitate substrate binding and product release. Moreover, in five of eight simulations without inhibitor (started from two X‐ray structures both with improperly formed oxyanion hole) the Thr132‐Gly133 peptide bond flips spontaneously thereby promoting the formation of the catalytically competent oxyanion hole, which then stays stable until the end of the runs. The simulation results provide evidence at atomic level of detail that the substrate binds to the NS2B‐NS3pro enzyme by conformational selection, rather than induced‐fit mechanism.
Transforming a NEP1 toxin gene into two Fusarium spp. to enhance mycoherbicide activity on Orobanche—failure and success
Authors: Meir Sagit , Amsellem Ziva , Al‐Ahmad Hani , Safran Einat , Gressel Jonathan 
Published: March 2009

AbstractBACKGROUND: The NEP1 gene encoding a fungal toxin that successfully conferred hypervirulence when transformed into Colletotrichum coccodes (Wallr.) Hughes attacking Abutilon theophrasti (L.) Medic. was tested to ascertain if it would enhance pathogenicity of Fusarium species to Orobanche aegyptiaca Pers. parasitising crops.RESULTS: None of the Fusarium oxysporum (#CNCM I‐1622) NEP1 transformants was hypervirulent. NEP1 transformants of a new but unnamed Fusarium sp. (#CNCM I‐1621—previously identified as F. arthrosporioides) killed Orobanche more rapidly than the wild type. Transformed lines of both species were NEP1 PCR positive, as was the wild type of F. oxysporum #CNCM I‐1622 and five other formae speciales of F. oxysporum. All six wild‐type formae speciales of F. oxysporum tested excrete minute amounts of immunologically and bioassay‐detectable NEP1‐like protein. NEP1 expression of most F. oxysporum transformants was suppressed, suggesting that the native gene and the transgene silence each other. The sequence of the putative NEP1 gene in Fusarium oxysporum #CNCM I‐1622 differs from the sequence in the toxin‐overproducing strain of F. oxysporum f. sp. erythroxyli in four or five amino acids in the first exon.CONCLUSION: Wild‐type Fusarium sp. #CNCM I‐1621 does not contain a NEP1‐like gene, explaining why it seemed amenable to transformation with high expression, and its virulence was probably enhanced by not cosuppressing the endogenous gene as occurred with Fusarium oxysporum #CNCM I‐1622. Copyright © 2009 Society of Chemical Industry
Peptide purification by affinity chromatography based on α‐ketoacyl group chemistry
Authors: Hara Toshiaki , Tainosho Akira , Nakamura Ken'ichiroh , Sato Takeshi , Kawakami Toru , Aimoto Saburo 
Published: March 2009

AbstractSignificant advances have been achieved in the fields of peptide/protein synthesis, permitting the preparation of large, complex molecules. Shortcomings, however, continue to exist in the area of peptide purification. This paper details some studies we undertook to develop a new strategy for peptide purification based on a reactivity of α‐ketoacyl groups in peptides. The α‐ketoacyl peptide was generated from Nε‐acyl‐lysyl‐peptide in the solid phase via a transamination reaction using glyoxylic acid and nickel(II) ion. Cleavage of the α‐ketoacyl group with o‐phenylenediamine gave the target peptide in an acceptable yield and purity. We first carried out a careful step‐by‐step optimization of the purification conditions using a model peptide. The strategy was then used in the purification of a transmembrane peptide that could not be effectively purified using a conventional RP‐HPLC system due to the strong hydrophobicity of the peptide and its high tendency to aggregate. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Anisotropic donor states in electric field
Authors: Zakrzewski Adam J. 
Published: March 2009

AbstractIn this paper we consider the application of the stabilization method to calculations of the ground state energy and resonance width of shallow donors in a uniform electric field. We show for the first time that within our formulation of this method it is very easy to include various factors influencing electronic structure of shallow impurities, like effective mass anisotropy or magnetic field. We demonstrate that the effective mass anisotropy significantly changes the lifetime of donor bound electrons. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparative cathodoluminescence characterization of ultrathin InN wells/GaN matrix MQWs grown on bulk‐GaN and MOVPE‐GaN
Authors: Hwang E. S. , Che S. B. , Ishitani Y. , Yoshikawa A. 
Published: March 2009

AbstractOne monolayer (1 ML) InN/GaN multiple quantum wells (MQWs) grown on bulk‐GaN and MOVPE‐GaN/ sapphire substrates with threading dislocation densities (TDDs) of about 106 cm–2 and 108 cm–2, respectively, were characterized by SEM‐CL measurements to study the effects of TDs on structural quality of InN/GaN MQWs. For the sample grown on bulk‐GaN substrate, step‐flow surface morphology and quite uniform spatial emission were observed as compared to the sample grown on MOVPE‐GaN/sapphire. CL peak energy at 86 K was observed at around 3.2 eV for both MQWs, but CL emission spectra from MQWs on bulk‐GaN substrate were five times stronger with smaller peak energy distribution, and full width at half maximum than those on MOVPE‐GaN substrate. This was caused by low‐TDD of bulk‐GaN substrate. Further, effects of growth temperature on 1 ML InN/GaN MQWs were investigated and it was found that CL peak energy tended to discretely shift to lower energy side, for e.g., from 3.18 eV to 2.9 eV when the growth temperature was decreased from 660 °C to 620 °C. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Innovative lift‐off solar cell made of monocrystalline‐silicon thin film by annealing of ordered macropores
Authors: Depauw Valérie , Gordon Ivan , Beaucarne Guy , Poortmans Jef , Mertens Robert , Celis Jean‐Pierre 
Published: March 2009

AbstractTo answer the challenge of obtaining thinner silicon solar cells, we developed a technique based on the transfer of a thin layer of high‐quality monocrystalline silicon to a foreign low‐cost substrate. The transfer is enabled by the reorganisation of macroporous silicon at high temperature: driven by the minimisation of their surface energy, pores close and, in specific situations, merge to form a large single void, a few micrometers under the wafer surface. As demonstrated in this paper, the micron‐thick film above it may be detached and used to process a solar cell. The difficulty of this approach lies in appropriately ordering the macropores, while its originality is to enable processing of a high‐quality material directly from porous silicon. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence of nanoporous silicon grains in TiO2 matrices
Authors: Frank Otakar , Kavan Ladislav , Kůsová Kateřina , Dohnalová Kateřina , Solovieva Natalia , Cibulka Ondřej , Pelant Ivan 
Published: March 2009

AbstractThe first attempts on introducing luminescent porous silicon agglomerates into various TiO2 thin‐film matrices (amorphous, crystalline and inverse opal) are reported. We describe preparation methods towards such matrices and how to impregnate them with luminescent Si nanocrystals (Si‐ncs). Si‐ncs keep their high luminescent capability in these matrices. Moreover, Si‐ncs embedded in the inverse TiO2 (anatase) opal matrix show marked modifications both in their emission spectrum and in luminescence dynamics. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Grafting stimuli‐responsive polymer brushes to freshly‐etched porous silicon
Authors: Segal Ester , Perelman Loren A. , Moore Troy , Kesselman Ellina , Sailor Michael J. 
Published: March 2009

AbstractThis work describes a simple two‐step method for grafting thermoresponsive amine‐terminated poly(N‐isopropylacrylamide) brushes to thin films of freshly‐etched porous Si. Grafting is achieved by pre‐hydrosilylation of the hydride‐terminated porous Si with undecylenic acid. The end carboxyl groups are activated and reacted with amine‐terminated poly(N‐isopropylacrylamide). Attachment of the polymer to the porous Si is confirmed by Fourier‐transform infrared (FTIR) spectroscopy and atomic force microscopy. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Refractive index contrast in porous silicon multilayers
Authors: Nava R. , de la Mora M. B. , Tagüeña‐Martínez J. , del Río J. A. 
Published: March 2009

AbstractTwo of the most important properties of a porous silicon multilayer for photonic applications are flat interfaces and a relative large refractive index contrast between layers in the optical wavelength range. In this work, we studied the effect of the current density and HF electrolyte concentration on the refractive index of porous silicon. With the purpose of increasing the refractive index contrast in a multilayer, the refractive index of porous silicon produced at low current was studied in detail. The current density applied to produce the low porosity layers was limited in order to keep the electrolyte flow through the multilayer structure and to avoid deformation of layer interfaces. We found that an electrolyte composed of hydrofluoric acid, ethanol and glycerin in a ratio of 3:7:1 gives a refractive index contrast around 1.3/2.8 at 600 nm. Several multilayer structures with this refractive index contrast were fabricated, such as dielectric Bragg mirrors and microcavities. Reflectance spectra of the structures show the photonic quality of porous silicon multilayers produced under these electrochemical conditions. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)