bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-resolution mapping of heterochromatin redistribution in a Drosophila position-effect variegation model
Authors: Vogel Maartje J , Pagie Ludo , Talhout Wendy , Nieuwland Marja , Kerkhoven Ron M , van Steensel Bas 
Published: January 2009

Abstract

Background
Position-effect variegation (PEV) is the stochastic transcriptional silencing of a gene positioned adjacent to heterochromatin. white-mottled X-chromosomal inversions in Drosophila are classic PEV models that show variegation of the eye color gene white due to its relocation next to pericentric heterochromatin. It has been suggested that in these models the spreading of heterochromatin across the rearrangement breakpoint causes the silencing of white. However, the extent of this spreading and the precise pattern of heterochromatin redistribution have remained unclear. To obtain insight into the mechanism of PEV, we constructed high-resolution binding maps of Heterochromatin Protein 1 (HP1) on white-mottled chromosomes.

Results
We find that HP1 invades euchromatin across the inversion breakpoints over ~175 kb and ~30 kb, causing de novo association of HP1 with 20 genes. However, HP1 binding levels in these regions show substantial local variation, and white is the most strongly bound gene. Remarkably, white is also the only gene that is detectably repressed by heterochromatin. Furthermore, we find that HP1 binding to the invaded region is particularly sensitive to the dosage of the histone methyltransferase Su(var)3-9, indicating that the de novo formed heterochromatin is less stable than naturally occurring constitutive heterochromatin.

Conclusion
Our molecular maps demonstrate that heterochromatin can invade a normally euchromatic region, yet the strength of HP1 binding and effects on gene expression are highly dependent on local context. Our data suggest that the white gene has an unusual intrinsic affinity for heterochromatin, which may cause this gene to be more sensitive to PEV than most other genes.
Amperometric nanobiosensor for quantitative determination of glyphosate and glufosinate residues in corn samples
Authors: Songa Everlyne A. , Somerset Vernon S. , Waryo Tesfaye , Baker Priscilla G. L. , Iwuoha Emmanuel I. 
Published: January 2009

Abstract
This study presents a simple, sensitive, rapid, and low-cost amperometric method for direct and quantitative determination of glyphosate and glufosinate herbicides. Electrochemical synthesis and characterization of poly(2,5-dimethoxyaniline)-poly(4-styrenesulfonic acid) (PDMA-PSS) nanoparticles was achieved by cyclic voltammetry (CV) and scanning electron microscopy (SEM). The nanobiosensor was constructed by immobilizing the enzyme horseradish peroxidase (HRP) electrostatically onto the surface of a rotating gold disk electrode modified with PDMA-PSS nanoparticles. The biosensing principle was based on determination of the sensor response to glyphosate and glufosinate by amperometric methods. Hydrogen peroxide (H2O2) was used to measure activity of the enzyme before injection of the herbicides into the electrolyte solution. The enzyme electrode was stable for a long period of time and was used for over 60 measurements. Glyphosate and glufosinate analyses were realized on spiked corn samples within a concentration range of 2.0-78.0 μg L-1, corroborating that the nanobiosensor is sensitive enough to detect herbicides in these matrices. Based on a 20-μL sample injection volume, the detection limits were 0.1 μg L-1 (10-10 M) for both glyphosate and glufosinate without sample clean-up or preconcentration.
From allenes to tetracenes: Syntheses, structures, and reactivity of the intermediates
Authors: Banide Emilie V. , Oulié Pascal , McGlinchey Michael J. 
Published: January 2009

AbstractEach step of the conversion of a series of 9-alkynyl-9H-fluorenes into the corresponding fluorenylidene-allenes that dimerize and proceed sequentially via head-to-tail and tail-to-tail dialkylidene-cyclobutanes, en route to electroluminescent tetracenes, has been characterized X-ray crystallographically. Allenes possessing substituents of very different electronic and steric character, such as aryl, halogeno, silyl, phosphino, and ferrocenyl, exhibit novel and unexpected reactivity patterns. The silyl-allenes dimerize to yield 1,2-bis(fluorenylidene)cyclobutanes of intrinsicC2symmetry as a result of the overlapping fluorenylidenes with their large wingspans. Thermal rearrangement of a bis(fluorenyl)-bis(trimethylsilyl)-diallene generates the tetrabenzo-quatercyclopentadiene, C60H36, which represents 60 % of the C60framework. An attempt to isolate a "push-pull" allene, whose central carbon possesses carbene character, was made by incorporating a cation-stabilizing substituent (ferrocenyl) and an aromatic anionic moiety (fluorenide) at the termini. However, the allene underwent facile dimerization to the very heavily congested 3,4-di(spirofluorenyl)-1,2-bis(ferrocenyl-chloromethylene)cyclobutane that exhibits a very long (1.65 Å) C(3)-C(4) bond. Extension of this chemistry to dibenzosuberenylidene-allenes led to a straightforward route to the hitherto difficultly available dibenz[c,d,h]azulene system. Moreover, the reaction of 5-phenylethynyl-5H-dibenzo[a,d]cyclohepten-5-ol with dicobalt octacarbonyl yielded, surprisingly, the first isolated example of a (μ-alkyne)Co2(CO)5(η2-alkene)complex, the long-sought first intermediate in the proposed mechanism of the Pauson-Khand reaction (PKR).
Magnetic field effects in chemical systems
Authors: Rodgers Christopher T. 
Published: January 2009

Abstract
Chemical reactions that involve radical intermediates can be influenced by magnetic fields, which act to alter their rate, yield, or product distribution. These effects have been studied extensively in liquids, solids, and constrained media such as micelles. They may be interpreted using the radical pair mechanism (RPM). Such effects are central to the field of spin chemistry of which there have been several detailed and extensive reviews. This review instead presents an introductory account of the field of spin chemistry, suitable for use by graduate students or researchers who are new to the area. It proceeds by giving a brief historical overview of the development of spin chemistry, before introducing the essential theory. This is then illustrated by application to a series of recent developments in solution-phase magnetic field effects (MFEs). The closing pages of this review describe the role played by spin chemistry in the remarkable magnetic compass sense of birds and other animals.
Schilddrüsendiagnostik in der Schwangerschaft. Referenzwerte und klinische Anwendung / Reference values for thyroid function tests during pregnancy
Authors: Spielhagen Christin , Bobermien Katja , Krebs Alexander , Wallaschofski Henri 
Published: January 2009

Zusammenfassung
Schilddrüsenerkrankungen gehören zu den häufigsten Stoffwechselstörungen der Frau im Reproduktionsalter und betreffen ca. 1 bis 2% aller Schwangerschaften. Da Schilddrüsenstoffwechselstörungen sowohl die Gesundheit der Mutter als auch eine gesunde Entwicklung des Kindes erheblich beeinträchtigen können, ist eine frühzeitige und exakte Diagnostik unerlässlich. Demgegenüber erschweren die physiologischen Veränderungen in der Schwangerschaft, unter anderem eine Zunahme des Plasmavolumens um 50%, ein Anstieg des Thyroxin-Bindungsglobulins und ein erhöhter Jodidbedarf die exakte Diagnostik und erfordern eine Anpassung der entsprechenden Schilddrüsenreferenzwerte zur Einschätzung des Schilddrüsenhormonstoffwechsels.
Evaluation of sample integrity measurement with VITROS® 5,1 FS chemistry system / Evaluation der Messung der Probenintegrität am VITROS® 5,1 FS
Authors: Knabbe Cornelius , Ratge Dieter , Christen Klaus , Sonntag Oswald 
Published: January 2009

Abstract
The measurement of sample integrity on a clinical laboratory system may help to avoid misleading results. The VITROS® 5,1 FS Chemistry System is a new analyzer which offers this feature. Approximately 50 diagnostic specimens were evaluated for the presence of hemolysis, icterus, and turbidity using MicroSensor™ technology onboard the VITROS® 5,1 FS. The samples were also assessed for hemoglobin concentration on a Lange photometer using the Harboe method and values were compared with the MicroSensor™ technology hemolysis index (H-index). For the icterus index (I-index), comparison was based on total bilirubin measured on the VITROS® system. To correlate the turbidity index (T-index), a comparison with triglycerides measured on the VITROS® 5,1 FS was undertaken. In addition, samples run on the VITROS® 5,1 FS were measured on a manual photometer at 700 nm. Good correlation was established between the manual Harboe method for measurement of hemoglobin and the VITROS® 5,1 FS H-index. For the I-index, a good correlation was observed compared to the quantitative bilirubin (TBIL slide) measurement. A poor correlation was expected for the comparison of the T-index with the triglycerides as measured on the VITROS® system. An additional study comparing the VITROS® MicroSensor T-index vs. manual photometer measurement at 700 nm yielded a very good correlation. The VITROS® 5,1 FS chemistry system MicroSensor™ technology measures the index for hemolyzed, icteric, and turbid samples. The indices correlate well compared to other methods for measuring these indices. Therefore, the use of MicroSensor™ technology offers a useful feature to identify samples containing optical interferents during routine work and to avoid misleading results by providing flags.
Evaluation of the Shear Modulus of Elastomeric Bridge Bearings Using Modal Data
Authors: Akbari Reza , Maalek Shahrokh 
Published: January 2009

Abstract
The current methods for the determination of the shear modulus for elastomeric bearings consist of the testing on a rather small part of the specimen cut from the manufactured bearing. Hence, such tests are destructive and at the same time, may not essentially represent the corresponding properties of the full size specimen with sufficient accuracy, due to the so-called “size effects.” Here, a modal-based nondestructive test method has been proposed which requires a rather simple modal testing apparatus and can be applied to find some important dynamic characteristics of the elastomeric bearings as well as its shear modulus. After the derivation of the dynamic characteristics of the specimens from modal analysis, the shear modulus has been obtained from modal analysis in conjunction with finite element analysis with different material properties that requires a series of finite element analyses based on a simple trial and error procedure. Four test specimens have been used and several tests have been carried out on each. Two of the test specimens were new elestomeric bearings and the other two were used bearings which have been in service for 35 years. The results demonstrate that the proposed method is a suitable manner in which important characteristics of the elastomeric bearings can be quantitatively obtained. Comparison of the results obtained from this method and conventional tests by ASTM have been discussed and some comments have been given on the results of tests on the new and old specimens.
A Critical Review of the Methodologies Employed for Determination of Tensile Strength of Fine-Grained Soils
Authors: Venkataramana K. , Rao B. Hanumantha , Singh D. N. 
Published: January 2009

Abstract
Tensile strength of fine-grained soils plays a significant role in assessing their cracking characteristics, which govern their suitability as a construction material for landfill liners and covers, earthen dams, embankments, and pavements. As such, determination of this property of these soils becomes essential. In this context, various experimental techniques that have been developed by earlier researchers to determine tensile strength of fine-grained soils are worth appreciating. Based on the experimental results obtained from these studies, several empirical relationships have been proposed. However, these relationships relate tensile strength of the soil with a single parameter (i.e., suction, plasticity index, liquid limit, CEC, clay content, or water content). This necessitates: (a) critical evaluation of such relationships, and (b) development of a generalized relationship that employs multiple soil properties. With this in view, investigations were carried out on some fine-grained soils and their tensile strength was determined by conducting undrained triaxial tests and suction measurements. Details of the methodologies adopted are presented in this paper and efforts have been made to achieve the two objectives mentioned above.
Indentation Measurements on Compacted Pharmaceutical Powders: Establishing the Sources of Variation in White Light Interferometer Dent Measurements
Authors: Hancock Bruno C. , Carlson Glenn T. , Langdon Beth A. , Ladipo Dauda D. , Mullarney Matthew P. , Vukovinsky Kim E. 
Published: January 2009

Abstract
Indentation measurements are commonly used to determine the mechanical properties of pharmaceutical compacts. Specifically, they are used to assess their resistance to plastic deformation and to help predict tablet properties. To date there has been little research reported aimed at understanding the variation associated with these types of measurements. In this work experiments were conducted to identify and, where possible, quantify the sources of variation for dent measurements on pharmaceutical excipient compacts using a white light interferometer. Statistical analyses of the results revealed that operator-to-operator and sample-to-sample variability each accounted for approximately 2.5 % of the total variability, whereas the intrinsic error of the experimental test procedure was about 10 % of the total variability. The remaining variability was due to known differences in the material properties or test conditions. The capability of the dent dimension measurements was determined to be approximately 8 % of the mean value, and thus it was possible to quantify the discriminating power of this type of compact mechanical property measurement.
Distribution and Habitat Associations of Radio‐Tagged Adult Lost River Suckers and Shortnose Suckers in Upper Klamath Lake, Oregon
Authors: Banish Nolan P. , Adams Barbara J. , Shively Rip S. , Mazur Michael M. , Beauchamp David A. , Wood Tamara M. 
Published: January 2009

AbstractRadiotelemetry was used to investigate the summer distribution and diel habitat associations of endangered adult Lost River suckers Deltistes luxatus and shortnose suckers Chasmistes brevirostris in northern Upper Klamath Lake, Oregon. From 2002 to 2004, Lost River and shortnose suckers were tracked by boat, and water depth and water quality were measured at each fish location. A series of water quality monitors were deployed in northern Upper Klamath Lake to provide temporal information on ambient temperature, pH, and dissolved oxygen, and water samples were collected to assess chlorophyll a concentration. Suckers moved into northern Upper Klamath Lake during June and began to leave in late September each year. Kernel density estimates revealed differences in the distribution in the northern portion of Upper Klamath Lake in 2002 and 2004. In 2003, however, both Lost River and shortnose suckers were commonly located within and offshore from Pelican Bay, a shallow (1.0‐2.0 m), groundwater‐influenced area of Upper Klamath Lake. This was especially obvious beginning in late July of 2003, concurrent with reduced dissolved oxygen levels (<4.0 mg/L) in the northern portion of Upper Klamath Lake that resulted from a die‐off of the cyanobacterium Aphanizomenon flos‐aquae. Both Lost River and shortnose suckers were generally associated with water depths greater than the mean depth (2.8 m) of northern Upper Klamath Lake. Evidence ratios did not suggest diel differences in depth, temperature, dissolved oxygen, or pH at sucker locations. Both Lost River and shortnose suckers generally occupied depths greater than 2.0 m, except when suckers sought refuge in Pelican Bay during periods of poor water quality. Despite the potential for increased avian predation, suckers appeared to benefit from moving into Pelican Bay rather than staying in areas where dissolved oxygen was low. Pelican Bay appears to be an important refugium and thus may be important for sucker conservation.
Academic Resilience and Reading: Building Successful Readers
Authors: McTigue Erin M. , Washburn Erin K. , Liew Jeffrey 
Published: January 2009

The socioemotional factors, which influence students' trajectories on their pathways to reading success, are often overlooked in literacy screenings and reading instruction. This article outlines the connections between personality factors, in particular resilient personalities, and early literacy success. It also offers teachers a series of six principles and supporting practices to facilitate socioemotional development situated in a second‐grade classroom with high‐quality reading instruction.كثيراً من الأحيان تتغاضى تحليلات التعلم وتعليم القراءة النظر عن عوامل العواطف الاجتماعية التي تؤثر مسار الطلاّب في طريقهم إلى القراءة الناجحة. لذا تحدد هذه المقالة الروابط بين عوامل شخصية وخصوصاً شخصيات مرنة ونجاح التعلم المبكر. وتقدم أيضاً للمعلمين سلسلة من ستة مبادئ وممارسات الدعم لتسهيل تنمية العواطف الاجتماعية مأخوذة من صف من الصفوف الثانية يتمتع بجودة عالية من تعليم القراءة.一些社会情绪因素，能影响到学生通往成功阅读之路的轨迹，可是却经常为读写能力筛选评估和阅读教学所忽略。本文概说学生人格因素，特别是富弹性的人格，与早期读写成功之间的各种关联。本文更给教师列出六项原则和一些支援教学的实践方法，以促进二年级学生在接受优质阅读教学时的社会情绪发展。Les facteurs socio‐affectifs, qui influent sur les trajectoires des élèves sur le chemin de la réussite en lecture, sont souvent survolés en ce qui concerne la lecture‐écriture et l'enseignement de la lecture. Cet article met l'accent sur les liens entre les facteurs de personnalité, notamment les personnalités résilientes, et la réussite en lecture au début de la scolarité. Il présente aussi aux enseignants une série de six principes et des pratiques de soutien afin de faciliter le développement socio‐affectif en contexte dans une classe de seconde année offrant un enseignement de la lecture de bonne qualité.При различных проверках грамотности и в самом процессе обучения чтению часто недоучитываются социально‐эмоциональные факторы, влияющие на те траектории, по которым двигаются ученики в своем общении с печатным словом. В статье очерчены связи между личностными факторами, в частности такими свойствами характера как жизнерадостность и гибкость, и ранним успехом в области грамотности. В статье также предложены шесть принципов и набор соответствующих методов, на основе которых можно успешно осуществлять социально‐эмоциональную поддержку второклассников при обучении чтению.Los factores socioemocionales que afectan las trayectorias de los alumnos en el camino hacia el éxito en la lectura son pasados por alto a menudo en los exámenes de lectura y la instrucción de lectura. Este artículo perfila las conexiones entre los factores de personalidad, especialmente los de personalidades elásticas, y el éxito a temprana edad en las competencias. También les ofrece a los maestros una serie de seis principios y prácticas que sirven de apoyo a estas prácticas para facilitar el desarrollo socioemocional en un salón de clase de segundo grado en el que la instrucción de lectura es de alta calidad.
Malignancy in Children with Trisomy 21
Authors: Rabin Karen R. , Whitlock James A. 
Published: January 2009

Learning Objectives
Evaluate malignancies for which children with Down syndrome are at increased and decreased risk in order to screen appropriately. Analyze the clinical and biologic features of transient myeloproliferative disease and acute megakaryoblastic leukemia in children with DS. Determine the clinical and biologic features of acute lymphoblastic leukemia in children with DS and outline treatment strategies.
This article is available for continuing medical education credit at CME.TheOncologist.com.
Radiation Interception and Yield Response to Increased Leaflet Number in Early‐Maturing Soybean Genotypes
Authors: Seversike Thomas M. , Purcell Larry C. , Gbur Edward , Chen Pengyin , Scott Roy 
Published: January 2009

ABSTRACTEarly‐maturing soybean [Glycine max (L.) Merr.] cultivars require less irrigation than full‐season cultivars and may mature before drought periods most often occur in the midsouthern United States. These cultivars require high plant‐population densities for radiation interception and acceptable yields, which increase costs. We hypothesized that seven‐leaflet genotypes would have greater leaf area per plant, resulting in more radiation interception and higher yield than near‐isogenic three‐leaflet genotypes at similar populations. Near‐isogenic lines from maturity groups 00 to 1.8 were seeded at rates from 4 to 80 m−2 The fraction of photosynthetically active radiation (PAR) intercepted by plots was measured using digital imagery and used to estimate cumulative intercepted PAR (CIPAR). Although seven‐leaflet isolines had greater leaf area per leaf than three‐leaflet isolines, leaf area per plant was similar between three‐ and seven‐leaflet isolines because the three‐leaflet isolines had a slightly greater number of main‐stem leaves than seven‐leaflet isolines. Generally, seven‐leaflet isolines had 10 to 21% greater CIPAR at populations ≤40 m−2 compared to three‐leaflet isolines. At populations ≤20 m−2, seven‐leaflet isolines generally had higher yields than three‐leaflet isolines, but yields at these low populations were inherently low and agronomically unacceptable.
Common Bean Landrace Jalo Listras Pretas Is the Source of a New Andean Anthracnose Resistance Gene
Authors: Gonçalves‐Vidigal M. C. , Filho Pedro S. Vidigal , Medeiros A. F. , Pastor‐Corrales M. A. 
Published: January 2009

ABSTRACTNovel sources of resistance are continuously needed to combat anthracnose disease in common bean (Phaseolus vulgaris L.) caused by the hypervariable pathogen Colletotrichum lindemuthianum (Sacc. and Magnus) Briosi and Cavara. We sought to characterize the novel anthracnose resistance in Andean common bean landrace ‘Jalo Listras Pretas’ (JLP). Jalo Listras Pretas is resistant to races 9, 64, 65, and 73 of the anthracnose pathogen used in this study. To examine inheritance of anthracnose resistance in JLP, F2 populations JLP/Mexico 222 and JLP/Cornell 49242 were inoculated with discriminating races of the pathogen. Segregation for resistance in both F2 populations fit a 3:1 resistant/susceptible ratio suggesting that the anthracnose resistance in JLP is controlled by a single dominant gene. To establish independence of the resistance gene in JLP from other published resistance genes, allelism tests were conducted with 14 F2 populations derived from crossing JLP with Andean cultivars carrying anthracnose resistance genes Co‐1, Co‐12, Co‐13, Co‐15, and Co‐12, and with Middle American cultivars with Co‐2, Co‐3, Co‐43, Co‐5, Co‐6, Co‐7, Co‐9, Co‐10, and Co‐11 Results revealed the resistance gene in JLP was independent of the Andean loci Co‐1 and Co‐12, and the nine Middle American anthracnose resistance genes. The symbol Co‐13 was assigned to this newly discovered anthracnose resistance gene in Brazilian Andean common bean landrace JLP.