bluuebunny/crossref_metadata_2025_split huggingface dataset:
False negative fecal occult blood tests due to delayed sample return in colorectal cancer screening
Authors: van Rossum Leo G.M. , van Rijn Anne F. , van Oijen Martijn G.H. , Fockens Paul , Laheij Robert J.F. , Verbeek Andre L.M. , Jansen Jan B.M.J. , Dekker Evelien 
Published: April 2009

AbstractDelayed return of immunochemical fecal occult blood test (iFOBT) samples to a laboratory might cause false negatives because of hemoglobin degradation. Quantitative iFOBT's became increasingly more accepted in colorectal cancer screening. Therefore, we studied the effects of delay between sampling and laboratory delivery on iFOBT performance. IFOBT positivity (≥50 ng/ml hemoglobin) in colorectal cancer screening participants without delay between sampling and laboratory delivery (<5 days), was compared with positivity in participants with ≥5 and ≥7 days delay. Additionally, positive tests were stored at room temperature and retested 5 times within 10–14 days. The sampling date was reported by 61% (n = 3,767) of the participants: in 19% delay was ≥5 days and in 5% ≥7 days. Compared with no‐delay, the adenoma detection rate was already significantly decreased after ≥5 days delay (OR 0.6; 95%CI 0.4–0.9). We retested iFOBT samples of 170 positives of which 139 (82%) had a colonoscopy: 45 (32%) had advanced adenomas (not colorectal cancer) and 8 (6%) had colorectal cancer. Mean daily fecal hemoglobin decrease was 29 ng/ml (S.D. 38 and median 11 ng/ml). In patients with advanced adenomas, hemoglobin in the sample was <50 ng/ml in 5 (11%) 2–3 days after the initial test and in 16 (36%) after 10–14 days. Seven days after the initial test, 2 (25%) colorectal cancer patients became false negative. Both had stage I colorectal cancer and initial values below 100 ng/ml, where the average for stage I is 532 ng/ml. Delay in sample return increased false negative immunochemical FOBT's. Mainly precursor lesions, but also colorectal cancer, will be missed due to delayed sample return. © 2009 UICC
Bayesian quantile regression methods
Authors: Lancaster Tony , Jae Jun Sung 
Published: April 2009

AbstractThis paper is a study of the application of Bayesian exponentially tilted empirical likelihood to inference about quantile regressions. In the case of simple quantiles we show the exact form for the likelihood implied by this method and compare it with the Bayesian bootstrap and with Jeffreys' method. For regression quantiles we derive the asymptotic form of the posterior density. We also examine Markov chain Monte Carlo simulations with a proposal density formed from an overdispersed version of the limiting normal density. We show that the algorithm works well even in models with an endogenous regressor when the instruments are not too weak. Copyright © 2009 John Wiley & Sons, Ltd.
Osteoclastogenesis on hydroxyapatite ceramics: The effect of carbonate substitution
Authors: Spence Gavin , Patel Nelesh , Brooks Roger , Bonfield William , Rushton Neil 
Published: April 2009

AbstractHuman osteoclasts derived from CD14+ve precursors were cultured on discs of stoichiometric hydroxyapatite (HA) and carbonate‐substituted hydroxyapatite (CHA) of varying carbonate contents. The development of osteoclasts was qualitatively different on ceramics compared to dentine, occurring in discrete, confluent subpopulations, which suggests local cell signaling may be important in the process. Resorption was quantified by scanning electron microscopy, surface profilometry, and by calcium release into the culture medium. Cells were characterised by a number of histochemical markers of the osteoclast phenotype. Resorption of the ceramic increased with increasing carbonate content up to 2.35 wt %, when resorption trails and pits characteristic of osteoclast activity were seen. Controlling carbonate content may be one way of controlling the rate of resorption of synthetic HA ceramics. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2010
The mass spectrometic fragmentation patterns of some biologically active derivatives of 2H‐1,2,4‐benzothiadiazine 1,1‐dioxides
Authors: Kirkien‐Rzeszotarski Alieja M. , Plimmer J. R. , Krees S. V. , Rzeszotarski W. J. 
Published: April 2009

AbstractThe mass spectra of some twenty‐six derivatives of 2H‐1,2,4‐benzothiadiazine 1,1‐dioxide are discussed. All compounds studied follow relatively simple fragmentation routes; as a consequence the fragmentation pattern gives a clear guide to the structure of the compound under investigation.
The reaction of carboxylic acid hydrazides with formaldehyde
Authors: Rosen Gerald M. , Gemmill Frederick Q. , Snoke Edgar O. , Popp Frank D. 
Published: April 2009

AbstractThe hydrazides of benzoic, phenyacetic, and 3‐phenylpropionic acids react with an acidic solution of formaldehyde to give15. Similar treatment of the corresponding methylhydrazides gave16. The ethers15can be cleaved to give, after methylation,16. Spectral data for15and16are presented.
The chemistry of 1,2,5‐thiadiazoles, IV. Benzo[1,2‐c:3,4‐c′:5,6‐c″] tris [1,2,5] thiadiazole
Authors: Komin Andrew P. , Carmack Marvin 
Published: April 2009

AbstractBenzo [1,2‐c:3,4‐c′:5,6‐c″] tris [1,2,5] thiadiazole (1) was synthesized from benzo [1,2‐c:3,4‐c′] ‐ bis [1,2,5] thiadiazole (11). Nitration of 11 gave compound 15, which on direct amination gave nitroamine 17. Reduction of 17 gave diamine 18, and cyclization of 18 with thionyl chloride gave 1. Diamine 18 was also cyclized with selenium oxychloride, glyoxal, 9,10‐phenanthrene‐quinone, and formic acid to give the compounds 4, 5, 19, and 6, respectively. A new procedure for the preparation of 2,1,3‐benzothiadiazole (7) from o‐phenylenediamine was used.
1,2,4‐Triazoles. V. Nuclear magnetic resonance study of N‐Methyl derivatives of 1,2,4‐triazoles
Authors: Kubota Seiju , Uda Masayuki , Nakagawa Toshiro 
Published: April 2009

AbstractThe chemical shifts of the N‐methyl protons of a number of N‐methylated‐1,2,4‐triazoles were studied. Substitution of methyl and methylthio groups in position 3 causes upfield shifts of the N‐methyl signals, while substitution of α‐pyridyl, γ‐pyridyl, and phenyl groups causes downfield shifts. In 3,5‐disubstituted 1,2,4‐triazoles, substituents in positions 3 and 5 have additive effects on the chemical shifts of N‐methyl groups, so that the chemical shifts of the N‐methyl groups of such compounds can be calculated. In this way, it was possible to assign the peaks of mixtures of N‐monomethylated derivatives obtained by methylation of 1,2,4‐triazoles.
Synthesis of 1,3‐dialkylpyrazolo [1,5‐a]‐1,3,5‐triazine‐2,4‐diones isomers of 1,3‐dialkylxanthines
Authors: Senga Keitaro , Kobe Joze , Robins Roland K. , O'Brien Darrell E. 
Published: April 2009

AbstractThe synthesis of a new series of alkylxanthine analogs containing a bridgehead nitrogen atom is reported. 1,3‐Dialkylpyrazolo[1,5‐a]‐1,3,5‐triazine‐2,4‐diones, were prepared by the treatment of 3‐methylpyrazolo[1,5‐a]‐1,3,5‐triazine‐2,4‐dione(3)with the corresponding alkyl iodide. Similarly, the reaction of 3‐methyl‐7‐phenylpyrazolo[1,5‐a]‐1,3,5‐dialkyl‐7‐phenylpyrazolo[1,5‐a]‐1,3,5‐triazine‐2,4‐diones. The starting materials,3and17, were preparedviathe reaction of an appropriate 3‐aminopyrazole with ethoxycarbonyl isothiocyanate. Several 8‐bromo derivatives were prepared by direct bromination of the 1,3‐dialkylpyrazolo[1,5‐a]‐1,3,5‐triazine‐2,4‐diones.
The preparation and synthetic utility of O‐substituted normethylmorphines
Authors: Borowitz Irving J. , Diakiw Vladimir 
Published: April 2009

AbstractPreviously described alkylation procedures on normethylmorphine in ethanol usually give low yields of N‐ and (phenolic) O,N‐alkylated products. While the O‐aikylation problem has been overcome for alkyl halides by doing the alkylations in dimethylformamide, reactive halides such as ethyl bromoacetate still give some O‐alkylation. Selective N‐acylation on normethylmorphine would present even more difficulty. We have developed syntheses of two phenolic O‐substituted normethylmorphines which allow selective reaction on nitrogen. 3,6‐Diacetylnormethylmorphine (normethylheroin) is prepared via the recently described trichloroethyl chloroformate method of Montzka et al. as applied to heroin. The reaction of N,N‐diethylcarbamoyl chloride on morphine gives 3‐(N,N‐diethylcarbamoyl)morphine, i.e. the phenolic hydroxyl is derivatized. Its 6‐acetyl derivatives is N‐demethylated by the von Braun (cyanogen bromide) method to give 3‐(N,N‐diethylcarbamoyl)normethylmorphine. Norheroin is monoalkylated in good yield on nitrogen with ethyl bromoacetate in dimethylformamide. It is similarly N‐acylated with chloroacetyl chloride in methylene chloride.
Preparation of 4,6‐diaminopyrazolo[3,4‐d] pyrimidines with variations in substitution at the 1‐ and 3‐positions
Authors: Southwick Philip L. , Dhawan Balram 
Published: April 2009

AbstractA number of new derivatives of 4,6‐diaminopyrazolo[3,4‐d]pyrimidines substituted in the 1‐ and/or 3‐positions have been obtained from reactions of guanidine carbonate with 1‐ and/or 3‐substituted‐5‐amino‐4‐cyanopyrazoles. Use of triethanolamine as a reaction medium permitted preparation of certain derivatives which could not be obtained from the previously described fusion procedure. Some derivatives of 4‐aminopyrazolo[3,4‐d]pyrimidine with substitution at the 1 ‐ and/or 3‐positions were also obtained from reactions of formamide with the same 5‐amino‐4‐cyanopyrazoles. The new compounds were screened for in vivo antimalarial activity, but were found inactive.
The synthesis of pyrimido[4,5‐c] pyridazines and pyrido[2,3‐d]pyrimidines related to toxoflavin and fervenulin
Authors: Billings Bernadette Kuo , Wagner Judith A. , Dan Cook Phillip , Castle Raymond N. 
Published: April 2009

Abstract4‐Deazatoxoflavin (1,6‐dimethyl‐1,5,6,7‐tetrahydropyrimido[4,5‐c]‐5,7‐pyridazinedione) (7) and several other 4‐deazatoxoflavin and 4‐deazafervenulin analogs have been prepared with the required intermediates. 3,5,7‐Trimethyl‐1,2,3,4‐tetrahydropyrido[2,3‐d]‐2,4‐pyrimidinedione (19) and 8‐phenyl‐3,5,7‐trimethyl‐2,3,4,8‐tetrahydropyrido[2,3‐d]‐2,4‐pyrimidinedione (20) were also prepared.
Synthesis of hydroxy‐6H‐benzofuro[3,2‐c] [1]benzopyran‐6‐ones
Authors: McPherson H. L. , Ponder B. W. 
Published: April 2009

AbstractThe Micheal addition of ethyl 2‐methoxy‐, 2,4‐dimethoxy‐ and 2,5‐dimethoxybenzoylacetates with benzoquinone leads to ethyl 2‐(rnethoxy or dimethoxy phenyl)‐5‐hydroxybenzofuran 3‐carboxylates. Treatment of the henzofuran derivatives with anhydrous pyridine hydrochloride at 190–195° leads to hydroxy‐6H‐henzofuro[3,2‐c] [1]benzopyran‐6‐ones.
Nrf2 activators provide neuroprotection against 6‐hydroxydopamine toxicity in rat organotypic nigrostriatal cocultures
Authors: Siebert Aubrey , Desai Vandan , Chandrasekaran Krish , Fiskum Gary , Jafri M. Samir 
Published: April 2009

AbstractOxidative stress and inflammation appear to play a critical role in the progression of Parkinson's disease. As a result, there has been growing interest in antioxidant pathways and how these pathways might be exploited to slow the progressive loss of dopamine neurons. One such pathway that has garnered attention recently is mediated by the transcription factor Nrf2 and is integral in orchestrating cells' antiinflammatory defense. Nrf2 controls the inducible expression of numerous antioxidant and phase 2 detoxification genes, such as glutathione S‐transferase, heme oxygenase‐1, and NAD(P)H:quinone oxidoreductase 1 (NQO1). Once activated, these genes work synergistically to maintain intracellular redox homeostasis. In this study, we test the hypothesis that Nrf2 activation can protect dopaminergic neurons against 6‐hydroxydopamine (6‐OHDA)‐induced toxicity. Treatment of organotypic nigrostriatal cocultures with either tert‐butylhydroquinone (tBHQ) or sulforaphane, known activators of Nrf2, mitigated dopaminergic cell loss. The observed protection appeared to be mediated, at least in part, by an increase in antioxidant activity. Simultaneous treatment of cultures with tBHQ and 6‐OHDA increased NQO1 expression 17‐fold compared with controls. Overall, these results suggest that Nrf2 may play an important role in cellular protection in neurodegenerative diseases and may be a viable therapeutic target in the future. © 2009 Wiley‐Liss, Inc.
Plant lipid composition is not affected by short‐term isotopic (13C) pulse‐labelling experiments
Authors: Wiesenberg Guido L. B. , Schneckenberger Katja , Kuzyakov Yakov , Schwark Lorenz 
Published: April 2009

AbstractPulse‐labelling of plants in a 14CO2 or 13CO2 atmosphere is a useful tool for investigating C allocation in plants and soils, revelation of C sources in soil organisms, as well as for CO2 partitioning studies. Recently, these labelling experiments have been used to produce isotopically labelled biomass of plants or microorganisms for the investigation of C dynamics in these organisms or in soil. However, it remains unknown whether these labelling approaches may affect the composition of plant constituents that react to modifications of environmental conditions during biosynthesis. Lipids as primary biosynthesis products and main components of plant waxes are well known to react fast to environmental changes resulting in a modified lipid composition. In this study, we demonstrate that lipid composition may be only slightly affected by the labelling procedure, especially, when only short pulses (only a few hours) are applied and when the sampling does not occur immediately after the labelling. While the differences of plant lipid compositions are obviously modified not as a result of isotopic pulses, the environmental conditions of plants grown under controlled laboratory conditions have a significant effect leading to a shift of the distribution pattern of plant lipids compared to the lipid composition of plants grown under field conditions.
Effects of olive oil polyphenols on erythrocyte oxidative damage
Authors: Paiva‐Martins Fátima , Fernandes João , Rocha Susana , Nascimento Henrique , Vitorino Rui , Amado Francisco , Borges Fernanda , Belo Luís , Santos‐Silva Alice 
Published: April 2009

AbstractMany studies have investigated the protective effects of oleuropein and hydroxytyrosol against cell injury, but few have investigated the protective effects of oleuropein aglycones 3,4‐dihydroxyphenylethanol‐elenolic acid (3,4‐DHPEA‐EA) and 3,4‐dihydroxyphenylethanol‐elenolic acid dialdehyde (3,4‐DHPEA‐EDA). The present work studied and compared the capacity of these four compounds, found at high concentrations in olive oil, to protect red blood cells (RBCs) from oxidative injury. Thein vitrooxidative stress of RBCs was induced by the water‐soluble radical initiator 2,2′‐azo‐bis(2‐amidinopropane) dihydrochloride. RBC changes were evaluated either by optical microscopy or by the amount of hemolysis. All compounds were shown to significantly protect RBCs from oxidative damage in a dose‐dependent manner. The order of activity at 20 μM was: 3,4‐DHPEA‐EDA > hydroxytyrosol > oleuropein > 3,4‐DHPEA‐EA. Even at 3 μM, 3,4‐DHPEA‐EDA and hydroxytyrosol still had an important protective activity. However, deleterious morphological RBC changes were much more evident in the presence of hydroxytyrosol than with 3,4‐DHPEA‐EDA. For the first time it was demonstrated that 3,4‐DHPEA‐EDA, one of most important olive oil polyphenols, may play a noteworthy protective role against ROS‐induced oxidative injury in human cells since lower doses of this compound were needed to protect RBCsin vitrofrom oxidative mediated hemolysis.
Normal testicular function and spermatogenesis
Authors: Shalet Stephen M. 
Published: April 2009

AbstractThe testis performs two basic functions, sperm production and testosterone secretion. Formation of the testis is genetically controlled; expression of the SRY gene directs the embryonic gonads into the pathway leading to the development of testes. By the fourth week of gestation in humans, the primordial germ cells derived from pluripotent cells of the embryonic epiblast proliferate and migrate from the endoderm of the yolk sac into the undifferentiated gonad, which becomes morphologically distinct during the seventh week of gestation in humans. Histological development of the testis is largely completed by the end of the third month of gestation. Pediatr Blood Cancer 2009;53:285–288. © 2009 Wiley‐Liss, Inc.
Toward non‐Born–Oppenheimer quantum chemistry
Authors: Takatsuka Kazuo 
Published: April 2009

AbstractA practical quantum theory for unifying electronic and nuclear dynamics, which were separated by the Born–Oppenheimer approximation, is proposed. The theory consists of two processes. Nonadiabatic (quantum) electron wavepacket dynamics on branching (non‐Born–Oppenheimer) nuclear paths are first constructed. Since these paths are not the classical trajectories, most of the existing semiclassical theories to generate quantum wavepacket do not work. Therefore, we apply our own developed semiclassical wavepacket theory to these generated non‐Born–Oppenheimer paths. This wavepacket is generated based on what we call the action decomposed function, which does not require the information of the so‐called stability matrix. Thus, the motion of nuclei is also quantized, and consequently the total wavefunction is represented as a series of entanglement between the electronic and nuclear wavepackets. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
A 3D graphical representation of DNA sequence based on numerical coding method
Authors: Cao Zhi , Li Renfa , Chen Weiyang 
Published: April 2009

AbstractRecently, we introduced a sort of numerical coding method of DNA sequences (Chen et al., MATCH Commun Math Comput Chem, 2008, 60, 291). On the basis of the result of our coding method, we present a 3D graphical representation of DNA sequences. The 3D graphical representation also avoids loss of information accompanying alternative 2D and 3D representation in which the curve standing for DNA overlaps and intersects itself. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Nonlinear dynamic analysis of frames with plastic hinges at arbitrary locations
Authors: Yan Z. H. , Au F. T. K. 
Published: April 2009

AbstractThis paper presents a method for nonlinear dynamic analysis of frames subjected to distributed loads, which is based on the semi‐rigid technique and moving node strategy. The plastic hinge is modelled as a pseudo‐semi‐rigid connection with nonlinear hysteretic moment–curvature characteristics at element ends. The stiffness matrix with material and geometric nonlinearities is expressed as a sum of products of the standard and geometric stiffness matrices with their corresponding correction matrices based on the plasticity‐factors developed from the section flexural stiffness at the plastic hinge locations. Each beam member is modelled by two elements. The moving node strategy is applied to the intermediate node to track the exact location of any intermediate plastic hinge that may be formed. Equilibrium iterations and geometry updating are carried out in every time step. Stiffness degradation is adopted to describe the deterioration of plastic hinges, and the effects of various parameters in the degradation model are evaluated. Examples are used to illustrate the applicability and excellent performance of the proposed method. Copyright © 2009 John Wiley & Sons, Ltd.
Ethnic differences in body composition and anthropometric characteristics in Australian Caucasian and urban Indigenous children
Authors: Kagawa Masaharu , Byrne Nuala M. , King Neil A. , Pal Sebely , Hills Andrew P. 
Published: April 2009

The objective was to compare ethnic differences in anthropometry, including size, proportions and fat distribution, and body composition in a cohort of seventy Caucasian (forty-four boys, twenty-six girls) and seventy-four urban Indigenous (thirty-six boys, thirty-eight girls) children (aged 9–15 years). Anthropometric measures (stature, body mass, eight skinfolds, thirteen girths, six bone lengths and five bone breadths) and body composition assessment using dual-energy X-ray absorptiometry were conducted. Body composition variables including total body fat percentage and percentage abdominal fat were determined and together with anthropometric indices, including BMI (kg/m2), abdominal:height ratio (AHtR) and sum of skinfolds, ethnic differences were compared for each sex. After adjustment for age, Indigenous girls showed significantly (P < 0·05) greater trunk circumferences and proportion of overweight and obesity than their Caucasian counterparts. In addition, Indigenous children had a significantly greater proportion (P < 0·05) of trunk fat. The best model for total and android fat prediction included sum of skinfolds and age in both sexes (>93 % of variation). Ethnicity was only important in girls where abdominal circumference and AHtR were included and Indigenous girls showed significantly (P < 0·05) smaller total/android fat deposition than Caucasian girls at the given abdominal circumference or AHtR values. Differences in anthropometric and fat distribution patterns in Caucasian and Indigenous children may justify the need for more appropriate screening criteria for obesity in Australian children relevant to ethnic origin.
Time- and sediment depth-related variations in bacterial diversity and community structure in subtidal sands
Authors: Böer Simone I , Hedtkamp Stefanie I C , van Beusekom Justus E E , Fuhrman Jed A , Boetius Antje , Ramette Alban 
Published: April 2009

Abstract
Bacterial community structure and microbial activity were determined together with a large number of contextual environmental parameters over 2 years in subtidal sands of the German Wadden Sea in order to identify the main factors shaping microbial community structure and activity in this habitat. Seasonal changes in temperature were directly reflected in bacterial activities and total community respiration, but could not explain variations in the community structure. Strong sediment depth-related patterns were observed for bacterial abundances, carbon production rates and extracellular enzymatic activities. Bacterial community structure also showed a clear vertical variation with higher operational taxonomic unit (OTU) numbers at 10–15 cm depth than in the top 10 cm, probably because of the decreasing disturbance by hydrodynamic forces with sediment depth. The depth-related variations in bacterial community structure could be attributed to vertical changes in bacterial abundances, chlorophyll a and NO3−, indicating that spatial patterns of microbes are partially environmentally controlled. Time was the most important single factor affecting microbial community structure with an OTU replacement of up to 47% over 2 years and a contribution of 34% to the total variation. A large part of this variation was not related to any environmental parameters, suggesting that temporal variations in bacterial community structure are caused by yet unknown environmental drivers and/or by stochastic events in coastal sand habitats. Principal ecosystem functions such as benthic oxygen consumption and extracellular hydrolysis of organic matter were, however, at a high level at all times, indicating functional redundancy in the microbial communities.
Interchanging Interactive 3D Graphics for Astronomy
Authors: Fluke C. J. , Barnes D. G. , Jones N. T. 
Published: April 2009

AbstractWe demonstrate how interactive, three-dimensional (3D) scientific visualizations can be efficiently interchanged between a variety of mediums. Through the use of an appropriate interchange format, and a unified interaction interface, we minimize the effort to produce visualizations appropriate for undertaking knowledge discovery at the astronomer's desktop, as part of conference presentations, in digital publications or as Web content. We use examples from cosmological visualization to address some of the issues of interchange and to describe our approach to adapting s2plot desktop visualizations to the Web2.