bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three methods to characterize reversed phase liquid chromatographic columns applied to pharmaceutical separations
Authors: Németh Tamás , Haghedooren Erik , Noszál Béla , Hoogmartens Jos , Adams Erwin 
Published: January 2008

AbstractSelecting a suitable reversed phase liquid chromatographic (RP‐LC) column for a particular separation is complicated. More than 600 brands of C18 columns are available on the market. Therefore, determining the characteristics influencing the selectivity of the different stationary phases is necessary. In this paper, three different methods to characterize RP‐LC columns are compared. Hoogmartens et al. developed a column characterization system based on test methods from literature, which were reduced with principal component analysis (PCA), and led to four final chromatographic parameters. The second method studied is this of Euerby et al. who developed a column classification system using six parameters, based on the method of Tanaka and also applying PCA. The third method, developed by Snyder et al. is different from the other two. It uses five parameters, calculated by multiple linear regression from the retention data of 18 solutes. The suitability of the column classification systems was examined on pharmaceutical separations. It seems that all three methods can facilitate the selection of a suitable column for an analysis. Copyright © 2008 John Wiley & Sons, Ltd.
Anchoring of Histidine‐Tagged Proteins to Molecular Printboards: Self‐assembly, Thermodynamic Modeling, and Patterning
Authors: Ludden Manon J. W. , Mulder Alart , Schulze Katrin , Subramaniam Vinod , Tampé Robert , Huskens Jurriaan 
Published: January 2008

AbstractIn this paper the multivalent binding of hexahistidine (His6)‐tagged proteins to β‐cyclodextrin (β‐CD) self‐assembled monolayers (SAMs) by using the nickel(II) complex of a hetero‐divalent orthogonal adamantyl nitrilotriacetate linker (4) is described. Nonspecific interactions were suppressed by using monovalent adamantyl‐hexa(ethylene glycol) derivative 3. With the mono‐His6‐tagged maltose binding protein (His6‐MBP), thermodynamic modeling based on surface plasmon resonance (SPR) titration data showed that the MBP molecules in solution were linked, on average, to Ni⋅4 in 1:1 stoichiometry. On the surface, however, the majority of His6‐MBP was complexed to surface‐immobilized β‐CDs through three Ni⋅4 complexes. This difference is explained by the high effective β‐CD concentration at the surface and is a new example of supramolecular interfacial expression. In a similar adsorption scheme, SPR proved that the α‐proteasome could be attached to β‐CD SAMs in a specific manner. Patterning through microcontact printing of (His6)4‐DsRed‐fluorescent timer (DsRed‐FT), which is a tetrameric, visible autofluorescent protein, was carried out in the presence of Ni⋅4. Fluorescence measurements showed that the (His6)4‐DsRed‐FT is bound strongly through Ni⋅4 to the molecular printboard.
The role of human epidermal growth factor receptor 2 in the survival of women with estrogen and progesterone receptor‐negative, invasive breast cancer: The California Cancer Registry, 1999–2004
Authors: Brown Monica , Tsodikov Alex , Bauer Katrina R. , Parise Carol A. , Caggiano Vincent 
Published: January 2008

AbstractBACKGROUNDBreast cancers that are negative for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) (triple negative [TN]) have been associated with high‐grade histology, aggressive clinical behavior, and poor survival. It has been determined that breast cancers that are negative for ER and PR but positive for HER2 (double negative [DN]) share features with TN breast cancers. In this report, the authors quantified the contribution of HER2 as well as demographic and tumor characteristics to the survival of women with TN tumors, DN tumors, and other breast cancers (OBC).METHODSIn total, 61,309 women who were diagnosed with invasive breast cancer between 1999–2004 were identified in the California Cancer Registry. Demographic and tumor characteristics of women with TN tumors were compared with those from women with DN tumors and women with OBC. A compound proportional hazards regression analysis (PHPH) (a generalization of the Cox proportional hazards model) was used to model these characteristics.RESULTSWomen with TN tumors were younger, African American, Hispanic, and of lower socioeconomic status (SES), whereas women with DN tumors were slightly older; African American, and Asian/Pacific Islander. Women with TN and DN tumors presented with larger, higher grade, and higher stage than women with OBC. Survival among women with TN tumors was poorer compared with that among women with OBC but was nearly the same as that of women with DN tumors. Results of the regression analysis indicated that disease stage, tumor grade, SES, and race/ethnicity were significant risk factors for survival. Negative ER and PR status was associated with an increased risk of death. There was a small but significant difference in both long‐term and short‐term survival patients who had TN tumors compared with patients who had DN tumors.CONCLUSIONSPatients with TN tumors shared many clinical, demographic, and tumor features and had survival that was very similar survival to that of patients with DN tumors, and survival for both groups contrasted greatly with survival for patients with OBC. Disease stage, tumor grade, SES, race/ethnicity, negative ER and PR status, rather than negative HER2 status, were risk factors for survival. Cancer 2008. © 2008 American Cancer Society.
Prognostic factors and survival in 1396 patients with uterine leiomyosarcomas
Authors: Kapp Daniel S. , Shin Jacob Y. , Chan John K. 
Published: January 2008

AbstractBACKGROUNDThe objectives of the current study were to determine the prognostic factors associated with disease‐specific survival (DSS) and to analyze the role of lymphadenectomy (LND) and oophorectomy in the management of uterine leiomyosarcomas (LMS).METHODSData were abstracted from the Surveillance, Epidemiology, and End Results database (1988–2003). Kaplan‐Meier and Cox proportional hazards regression models were used for analyses.RESULTSThe median age of the 1396 patients was 52 years. There were 951 patients (68.1%) with International Federation of Gynecology and Obstetrics (FIGO) stage I disease, 43 patients (3.1%) with stage II disease, 99 patients (7.1%) with stage III disease, and 303 patients (21.7%) with stage IV disease. Distribution by tumor grade included 87 patients with grade 1 tumors, 208 with grade 2, and 509 patients with grade 3 tumors. The 5‐year DSS rates for patients with stage I, II, III, and IV disease were 75.8%, 60.1%, 44.9%, and 28.7%, respectively. Lymph node metastases were identified in 23 of 348 patients (6.6%) who underwent LND. The 5‐year DSS rate was 26% in patients who had positive lymph nodes compared with 64.2% in patients who had negative lymph nodes (P < .001). Of 341 patients aged <50 years with stage I or II disease, 240 (70.4%) underwent oophorectomy. There was no difference in 5‐year DSS based on oophorectomy. On multivariate analysis, older age at diagnosis, more recent year of diagnosis, African‐American race, higher tumor grade, higher stage of disease, and lack of primary surgical treatment all were associated significantly with worse survival.CONCLUSIONSIndependent predictors of DSS in patients with uterine LMS included age, race, stage, grade, and primary surgery. Oophorectomy was not found to have an independent impact on survival. Cancer 2008. © 2008 American Cancer Society.
p75NTR expression in rat urinary bladder sensory neurons and spinal cord with cyclophosphamide‐induced cystitis
Authors: Klinger Mary Beth , Girard Beatrice , Vizzard Margaret A. 
Published: January 2008

AbstractA role for nerve growth factor (NGF) in contributing to increased voiding frequency and altered sensation from the urinary bladder has been suggested. Previous studies have examined the expression and regulation of tyrosine kinase receptors (Trks) in micturition reflexes with urinary bladder inflammation. The present studies examine the expression and regulation of another receptor known to bind NGF, p75NTR, after various durations of bladder inflammation induced by cyclophosphamide (CYP). CYP‐induced cystitis increased (P ≤ 0.001) p75NTR expression in the superficial lateral and medial dorsal horn in L1–L2 and L6–S1 spinal segments. The number of p75NTR‐immunoreactive (‐IR) cells in the lumbosacral dorsal root ganglia (DRG) also increased (P ≤ 0.05) with CYP‐induced cystitis (acute, intermediate, and chronic). Quantitative, real‐time polymerase chain reaction also demonstrated significant increases (P ≤ 0.01) in p75NTR mRNA in DRG with intermediate and chronic CYP‐induced cystitis. Retrograde dye‐tracing techniques with Fastblue were used to identify presumptive bladder afferent cells in the lumbosacral DRG. In bladder afferent cells in DRG, p75NTR‐IR was also increased (P ≤ 0.01) with cystitis. In addition to increases in p75NTR‐IR in DRG cell bodies, increases (P ≤ 0.001) in pericellular (encircling DRG cells) p75NTR‐IR in DRG also increased. Confocal analyses demonstrated that pericellular p75NTR‐IR was not colocalized with the glial marker, glial fibrillary acidic protein (GFAP). These studies demonstrate that p75NTR expression in micturition reflexes is present constitutively and modified by bladder inflammation. The functional significance of p75NTR expression in micturition reflexes remains to be determined. J. Comp. Neurol. 507:1379–1392, 2008. © 2008 Wiley‐Liss, Inc.
Fine structure of the visual dorsolateral anterior thalamic nucleus of the pigeon (Columba livia): A hodological and GABA‐immunocytochemical study
Authors: Miceli Dom , Repérant Jacques , Ward Roger , Rio Jean‐Paul , Jay Bruno , Médina Monique , Kenigfest Natalia B. 
Published: January 2008

AbstractThe ultrastructure of the lateroventral subcomponent of the visual dorsolateral anterior thalamic nucleus of the pigeon (DLLv) was analyzed using hodological techniques and GABA‐immunocytochemistry. Two types of GABA‐immunonegative hyperpalliopetal neurons and a single type of strongly GABA‐immunoreactive (‐ir) interneuron were identified, the latter displaying long dendrites with some containing synaptic vesicles (DCSV). Ten types of axon terminal were identified and divided into two categories. The first, GABA‐immunonegative and making asymmetrical synaptic contact, contain round (RT1, RT2, RT3) or pleiomorphic synaptic and many dense‐core vesicles (DCT). RT1 terminals are retinothalamic and RT2 terminals hyperpalliothalamic; both mainly contact dendrites of projection neurons (72% and 78% respectively), less frequently dendrites of interneurons and sometimes DCSV; RT1 terminals are rarely involved in synaptic triads. The second category are consistently GABA‐immunopositive. Four types (PT1–4), distinguished by their pleiomorphic synaptic vesicles, make symmetrical synaptic contact essentially with dendrites of projection neurons, more rarely on dendrites of interneurons (PT2). PT1 terminals are very probably those of interneurons, whereas the rare PT4 terminals are of retinal origin. A fifth type (RgT) contains round synaptic vesicles and makes asymmetrical synaptic contact with dendrites of projection neurons and interneurons. PT2 and RgT terminals occasionally contact DCSV of interneurons, which are sometimes involved in synaptic triads. Two final subcategories (DCgT1–2) contain many dense‐core vesicles. Our findings are compared with those of previous studies concerning the fine structure and neurochemical properties of the GLd of reptiles and mammals, with special reference to the origin of the extraretinal and extracortical projections to this structure. J. Comp. Neurol. 507:1351–1378, 2008. © 2008 Wiley‐Liss, Inc.
Characterization of Atmospheric Particulate: Relationship between Chemical Composition, Size, and Emission Source
Authors: Di Tullio Alessandra , Reale Samantha , Ciammola Margherita , Arrizza Lorenzo , Picozzi Pietro , De Angelis Francesco 
Published: January 2008

AbstractPhysicochemical characterization of particulate matter fractionated into eight samples by size from 10 to 0.43 μm was performed by HS‐SPME/GC‐MS for the organic (semi‐)volatile components and SEM X‐ray microanalysis (SEM/EDX) for analysis of the elemental composition. The HS‐SPME technique was shown to be efficient with respect to requiring an extremely low amount of material, being selective and clean and avoiding use of any solvents. Particulate matter was collected at four sites characterized by particular environmental locations and different pollution levels around the city of L′Aquila in central Italy. The results reveal a tight correlation between the particle composition, size, and the emission source. The analyses show also that the finer the particle, the higher its content of elemental carbon and organic compounds. Well‐known carcinogens such as PAHs were detected among the identified organic compounds from both the rural and highly polluted sites.
Expression pattern of Popdc2 during mouse embryogenesis and in the adult
Authors: Froese Alexander , Brand Thomas 
Published: January 2008

AbstractThe Popdc2 gene is a member of the Popeye domain containing gene family encoding membrane proteins with prominent expression in striated and smooth muscle tissue. After introducing a LacZ reporter gene into the Popdc2 locus, expression was studied during embryonic development and postnatal life. At embryonic day (E) 7.5, expression was present in cardiac and extraembryonic mesoderm. At E10.5, expression was found in heart, somites, and mesothelial cells lining the coelom. At E12.5, expression was present in the coelomic mesothelium, pericardial and myocardial layer of the heart, skeletal muscle, bladder, gut, and umbilical vessels. Postnatal expression was found in cardiac and skeletal muscle and in the smooth muscle layer of colon, rectum, and bladder. In the stomach, Popdc2 was exclusively present in the pyloric epithelium. In conclusion, Popdc2 is expressed in various muscle and nonmuscle cell types during embryonic development and in postnatal life. Developmental Dynamics 237:780–787, 2008. © 2008 Wiley‐Liss, Inc.
P‐Chirogenic Benzo‐Fused Phenoxaphosphane: Synthesis, Resolution and Study of the Stereochemical Properties of the Corresponding Palladium Complexes
Authors: Doro Franco , Lutz Martin , Reek Joost N. H. , Spek Anthony L. , van Leeuwen Piet W. N. M. 
Published: January 2008

AbstractThe synthesis and resolution of chiral phenoxaphosphane 3, with the stereogenic center at the phosphorus atom, is described. Compound 3 has been synthesized following a well‐known procedure for trapping a phosphorus atom within a six‐membered ring. The resolution of the racemic mixture of 3 was achieved through separation of its diastereomeric palladacycle derivatives 7a,b and 9a,b. The absolute configuration of enantiopure phosphanes 3a,b was assigned unequivocally by means of X‐ray crystal structure determination for complex 9a and by combination of NOE(1H–1H)/COSY(1H,1H) spectroscopy and DFT calculations for complexes 7a,b, which in both cases led to identical results. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Separation and determination of flavonoids using microemulsion EKC with electrochemical detection
Authors: Yu Li‐Shuang , Xu Xue‐Qin , Huang Lu , Ling Jin‐Ming , Chen Guo‐Nan 
Published: January 2008

AbstractA selective and sensitive method of microemulsion EKC (MEEKC) with electrochemical detection (ED) was developed for separation and determination of 14 flavonoids. In order to obtain the better stability for the studied flavonoids, oil (ethyl acetate) with low interfacial surface tension was employed as organic solvent. A running buffer composed of 0.9% (w/v, 30 mM) SDS, 0.9% (w/v, 21 mM) sodium cholate (SC), 0.9% (w/v, 121 mM) butan‐1‐ol, 0.6% (w/v, 68 mM) ethyl acetate, and 98.2% v/v 10 mM Na2B4O7–20 mM H3BO3 buffer (pH 7.5) was applied for the separation of flavonoids. Under the optimum conditions, the relationship between peak currents and analyte concentrations was linear over about 1.3 and 1.7 orders of magnitude with detection limits (defined as S/N = 3) ranging from 0.02 to 0.5 μg/mL for all analytes. This method was applied for the determination of flavonoids in real samples with simple extraction procedures, and the assay results were satisfactory.
Improved hydrostatic pressure sample injection by tilting the microchip towards the disposable miniaturized CE device
Authors: Wang Wei , Zhou Fang , Zhao Liang , Zhang Jian‐Rong , Zhu Jun‐Jie 
Published: January 2008

AbstractA simple method of hydrostatic pressure sample injection towards a disposable microchip CE device was developed. The liquid level in the sample reservoir was higher than that in the sample waste reservoir (SWR) by tilting microchip and hydrostatic pressure was generated, the sample was driven to pass through injection channel into SWR. After sample loading, the microchip was levelled for separation under applied high separation voltage. Effects of tilted angle, initial liquid height and injection duration on electrophoresis were investigated. With enough injection duration, the injection result was little affected by tilted angle and initial liquid heights in the reservoirs. Injection duration for obtaining a stable sample plug was mainly dependent on the tilted angle rather than the initial height of liquid. Experimental results were consistent with theoretical prediction. Fluorescence observation and electrochemical detection of dopamine and catechol were employed to verify the feasibility of tilted microchip hydrostatic pressure injection. Good reproducibility of this injection method was obtained. Because the instrumentation was simplified and no additional hardware was needed in this technology, the proposed method would be potentially useful in disposable devices.
On‐column detection of multiphoton‐excited fluorescence in CE using hyphenated cylindrical‐square capillaries
Authors: Xu Youzhi , Chen Sheng , Feng Xiaojun , Du Wei , Luo Qingming , Liu Bi‐Feng 
Published: January 2008

AbstractMultiphoton‐excited fluorescence (MPEF) is a complementary and useful mode of LIF detection in CE with advantages of ultra‐low mass detectability and spectral excitability, but it is currently quite limited by its end‐column configuration. In this article, we demonstrate a novel strategy of on‐column schemes that can greatly facilitate MPEF detection in CE. FITC‐labeled amine species were used as the model samples for the evaluation and comparison of those detection scenarios. By using the square capillary instead of the conventional cylindrical one, the on‐column MPEF could be readily achieved, with detection sensitivity of 0.72 μM that was comparable with the end‐column mode. However, this strategy unfavorably reduced separation efficiency. The theoretical plate number on averaging all the sample peaks was significantly decreased from 283 000 to 19 000/m. To minimize such an influence, a short square capillary acting as an on‐column MPEF detection cell was then mounted to a long cylindrical capillary responsible for the CE separation. Results indicated that both high separation efficiency (240 000/m) and better detectability (0.42 μM) were realized simultaneously by using this binary‐capillary configuration. Quantitative analysis was performed under the optimized detector configuration and revealed a linear dynamic range of 2 orders of magnitude, with mass detection limit down to the mid‐yottomole level.
Lab‐on‐valve for the automatic determination of the total content and individual profiles of linear alkylbenzene sulfonates in water samples
Authors: Jiménez José Ruiz , Luque de Castro María D. 
Published: January 2008

AbstractMethods for the total content and individual determination of linear alkylbenzene sulfonates (LAS) in water samples based on the use of a lab‐on‐valve (LOV) module alone or coupled to CE equipment, respectively, have been developed. The total content of LAS has been determined by intrinsic absorption measurements (DA method) and after reaction with a methyl orange–cetylpyridine chloride mixture (MO method) with detection limits (LODs) of 21 ng/L and 15 μg/L, respectively, quantification limits (LOQs) of 70 ng/L, 50 μg/L, and development times of 100 and 124 s, respectively. The method for individual separation–quantification of LAS at very low concentration is based on automatic SPE preconcentration in the LOV module coupled on‐line with the CE equipment. The LODs and LOQs thus obtained range between 1–21 and 4–70 ng/L, respectively, with linear dynamic ranges from the LOQ to 10 μg/L. Preconcentration factors of 10 000 and high efficiency to eliminate interferents by SPE enable application of the method to treated effluent, waste, surface and sea waters.
Determination of uranium, iron, copper, and nickel from ore samples by MEKC using N,N′‐ethylene bis(salicylaldimine) as complexing reagent
Authors: Mirza Muhammed Aslam , Khuhawar Muhammad Yar , Arain Rafee 
Published: January 2008

AbstractAn analytical procedure has been developed for the separation of dioxouranium(VI), iron(III), copper(II), nickel(II), cobalt(II), cobalt(III), palladium(II), and thorium(IV) by MEKC using N,N′‐ethylene bis(salicylaldimine) (H2SA2en) as a complexing reagent with total runtime <4.5 min. SDS was used as micellar medium at pH 8 with sodium tetraborate buffer (0.1 M). An uncoated fused‐silica capillary with an effective length of 50 cm×75 μm id was used with an applied voltage of 30 kV with photodiode array detection at 231 nm. Linear calibrations were obtained within 0.111–1000 μg/mL of each element with LODs within 37–325 ng/mL. The developed method was tested for analysis of uranium ore samples indicating its presence within 103–1789 μg/g with RSD within 0.79–1.87%. Likewise copper, nickel, and iron in their combined matrix were also simultaneously determined with RSD 0.4–1.6% (n = 6).
Single nucleotide polymorphism detection in the hMSH2 gene using conformation‐sensitive CE
Authors: Chen Yen‐Ling , Jong Yuh‐Jyh , Ferrance Jerome , Hsien Jan‐Sing , Shih Chi‐Jen , Feng Chia‐Hsien , Wu Ming‐Tsang , Wu Shou‐Mei 
Published: January 2008

AbstractCE allows for highly reproducible analysis of DNA fragments which can be used to detect DNA mutations including SNPs. We have utilized a simple and direct CE analysis method for SNP analysis called conformation‐sensitive CE (CSCE), based on the principle of single nucleotide different to produce conformational changes in the mildly denaturing solvent system. This method was applied to analysis of a mutation in the promoter region of the hMSH2 gene. This gene belongs to the human DNA mismatch repair system, which is responsible for recognizing and repairing mispaired nucleotides, and mutations in the hMSH2 gene are known to cause hereditary nonpolyposis colorectal cancer (HNPCC). PCR fragments generated from the promoter region of the hMSH2 gene, displaying either a C/C homozygote, C/T heterozygote, or T/T homozygote genotype, did not require further pretreatment before electrokinetic injection. The CE separation, using a 1×Tris‐borate‐EDTA (TBE) buffer containing 3% w/v hydroxylethyl cellulose (HEC) and 6 M urea, was performed under reverse polarity with a separation temperature of 15°C. The genotypes of 204 healthy volunteers and 13 colorectal cancer patients were determined using CSCE, and the results confirmed by DNA sequencing. While the CSCE separations were shown to be highly reproducible and sensitive for screening large populations, no correlation was observed between cancer patients and this hMSH2 gene polymorphism.