bluuebunny/crossref_metadata_2025 huggingface dataset:
BALB/c mice have more CD4+CD25+ T regulatory cells and show greater susceptibility to suppression of their CD4+CD25− responder T cells than C57BL/6 mice
Authors: Chen Xin , Oppenheim Joost J , Howard O M Zack
Published: April 2005

Increasing evidence indicates that CD4+CD25+ T regulatory (Treg) cells control a wide spectrum of immune responses. The initial identification of CD4+CD25+ Treg cell as a “professional suppressor” was based on observations made in BALB/c mice. This mouse strain is well known to preferentially develop T helper cell type 2 responses, to be more susceptible to intracellular parasite infection, to have a higher tumor incidence, and to be more resistant to the induction of autoimmune diseases, as compared with C57BL/6 (B6) mice. We therefore decided to compare Treg cell function of B6 and BALB/c mice. We observed that the frequency of CD4+CD25+ T cells in the thymus and peripheral lymphoid organs of BALB/c mice was higher than in B6 mice. CD4+CD25+ Treg cells from both mouse strains shared similar phenotypic properties, including expression of characteristic immunological markers and hyporesponsiveness to T cell receptor cross-linking and in their capacity to suppress proliferation of BALB/c CD4+CD25− T responder (Tres) cells. However, CD4+CD25− Tres cells from B6 mice were notably less susceptible to suppression by CD4+CD25+ Treg cells from either mouse strain. Our data suggest that the number and the level of suppression of CD4+CD25+ Treg cells for CD4+CD25− Tres cells may be dictated by genetic background. Our data also suggest that differences in the CD4+CD25+ Treg cell number and the susceptibility of CD4+CD25− Tres cells may, at least in part, account for the differences in immune response between B6 and BALB/c strains of mice.
Up-regulation of GRP78 and antiapoptotic signaling in murine peritoneal macrophages exposed to insulin
Authors: Misra Uma Kant , Pizzo Salvatore Vincent
Published: April 2005

The unfolded protein response pathway (UPR) compensates for excessive protein accumulation in the endoplasmic reticulum (ER). As insulin induces global protein synthesis, it may cause accumulation of unfolded proteins in the ER, thus triggering UPR. We assessed UPR activation in insulin-treated murine peritoneal macrophages using a number of markers including 78 kDa glucose response protein (GRP78), X-box-binding protein (XBP)-1, pancreatic ER kinase (PERK), eukaryotic initiation factor 2 (eIF2)α, and growth arrest and DNA damage (GADD)34. Exposure of cells to insulin activated UPR, as evidenced by an increased expression of GRP78, XBP-1, phosphorylated PERK (p-PERK), and p-eIF2α. The insulin-induced, elevated expression of GRP78 was comparable with that observed with tunicamycin, a classical inducer of ER stress. Concomitantly, insulin also up-regulated prosurvival mechanisms by elevating GADD34 and elements of the antiapoptotic pathway including Bcl-2, X-linked inhibitor of apoptosis, and phosphorylated forkhead transcription factor. In conclusion, we show here that insulin treatment does cause ER stress in macrophages, but insulin-dependent mechanisms overcome this ER stress by up-regulating UPR and the antiapoptotic pathway to promote cell survival.
Type I and type II interferons delay human neutrophil apoptosis via activation of STAT3 and up-regulation of cellular inhibitor of apoptosis 2
Authors: Sakamoto Erina , Hato Fumihiko , Kato Takayuki , Sakamoto Chikahiko , Akahori Mika , Hino Masayuki , Kitagawa Seiichi
Published: April 2005

We have recently demonstrated that granulocyte-colony stimulating factor (G-CSF) delays human neutrophil apoptosis via up-regulation of cellular inhibitor of apoptosis 2 (cIAP2), which is dependent on activation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3). Here, we show that type I and type II interferons (IFNs), which bind to the distinct receptors, exert the antiapoptotic effect on human neutrophils through the similar mechanism. IFN-α (type I IFN) and IFN-γ (type II IFN), like G-CSF, delayed human neutrophil apoptosis through the protein synthesis-dependent mechanism. Stimulation of neutrophils with IFN-α or IFN-γ resulted in tyrosine phosphorylation of STAT1 and STAT3 but not phosphorylation of STAT5, Akt, extracellular signal-regulated kinase, and p38 mitogen-activated protein kinase. IFN-α and IFN-γ induced the expression of transcripts of cIAP2 and suppressor of cytokine signaling 1 and 3, but not cIAP1, Mcl-1, and A1. IFN-α- and IFN-γ-induced up-regulation of cIAP2 mRNA and protein, phosphorylation of STAT3, and antiapoptotic effect were inhibited significantly by pretreatment of cells with AG490, a specific inhibitor of JAK2. These findings suggest that cIAP2 expression is up-regulated by IFN-α and IFN-γ through, at least in part, activation of the JAK2-STAT3 pathway, and increased expression of the cIAP2 protein may contribute to an IFN-α- and IFN-γ-mediated antiapoptotic effect on human neutrophils.
Insulin Receptor Substrates-1 and -2 Are Both Depleted but via Different Mechanisms after Down-Regulation of Glucose Transport in Rat Adipocytes
Authors: Renström Frida , Burén Jonas , Eriksson Jan W.
Published: April 2005

Alterations in muscle and adipose tissue insulin receptor substrate (IRS)-1 and IRS-2 are associated with, and commonly believed to contribute to, development of insulin resistance. In this study, we investigated the mechanisms behind previously observed reductions in IRS levels due to high concentrations of glucose and insulin and their significance in the impairment of glucose uptake capacity in primary rat adipocytes. Semiquantitative RT-PCR analysis showed that insulin (104 μU/ml) alone or in combination with glucose (15 mm) markedly suppressed IRS-2 gene expression, whereas IRS-1 mRNA was unaffected by the culture conditions. The negative effect of a high glucose/high insulin setting on IRS-1 protein level was still exerted when protein synthesis was inhibited with cycloheximide. Impairment of glucose uptake capacity after treatment with high glucose and insulin was most pronounced after 3 h, whereas IRS-1 and IRS-2 protein levels were unaffected up to 6 h but were reduced after 16 h. Moreover, impaired glucose uptake capacity could only partially be reversed by subsequent incubation at physiological conditions. These novel results suggest that: 1) in a high glucose/high insulin setting depletion of IRS-1 and IRS-2 protein, respectively, occurs via different mechanisms, and IRS-2 gene expression is suppressed, whereas IRS-1 depletion is due to posttranslational mechanisms; 2) IRS-1 and IRS-2 protein depletion is a secondary event in the development of insulin resistance in this model of hyperglycemia/hyperinsulinemia; and 3) depletion of cellular IRS in adipose tissue may be a consequence rather than a cause of insulin resistance and hyperinsulinemia in type 2 diabetes.
Identification of Murine Uterine Genes Regulated in a Ligand-Dependent Manner by the Progesterone Receptor
Authors: Jeong Jae-Wook , Lee Kevin Y. , Kwak Inseok , White Lisa D. , Hilsenbeck Susan G. , Lydon John P. , DeMayo Francesco J.
Published: April 2005

Progesterone (P4) acting through its cognate receptor, the progesterone receptor (PR), plays an important role in uterine physiology. The PR knockout (PRKO) mouse has demonstrated the importance of the P4-PR axis in the regulation of uterine function. To define the molecular pathways regulated by P4-PR in the mouse uterus, Affymetrix MG U74Av2 oligonucleotide arrays were used to identify alterations in gene expression after acute and chronic P4 treatments. PRKO and wild-type mice were ovariectomized and then treated with vehicle or 1 mg P4 every 12 h. Mice were killed either 4 h after the first injection (acute P4 treatment) or after the fourth injection of P4 (chronic P4 treatment). At the genomic level, the major change in gene expression after acute P4 treatment was an increase in the expression of 55 genes. Conversely, the major change in gene expression after chronic P4 treatment was an overall reduction in the expression of 102 genes. In the analysis, retinoic acid metabolic genes, cytochrome P 450 26a1 (Cyp26a1), alcohol dehydrogenase 5, and aldehyde dehydrogenase 1a1 (Aldh1a1); kallikrein genes, Klk5 and Klk6; and specific transcription factors, GATA-2 and Cited2 [cAMP-corticosterone-binding protein/p300-interacting transactivator with glutamic acid (E) and aspartic acid (D)-rich tail], were validated as regulated by the P4-PR axis. Identification and analysis of these responsive genes will help define the role of PR in regulating uterine biology.
The digital injection of signals into machine feedback loops via incremental encoder interfaces
Authors: Freeman J M , Ford D G
Published: April 2005

The paper outlines the methods available for the application of test inputs and the measurement of the response of computer numerical control (CNC) machines to changes in position set point. A new approach is described where a signal is injected digitally into the feedback loop of a CNC machine, and how this can be done using the compensation register of an incremental encoder interface board is considered. In principle, any signal can be added in this way, error correction, a test signal, etc. Indeed, several signals can be added ‘simultaneously’ into the various axes of the machine. However, the controller has built-in limits to the unpro-grammed moves that it will tolerate and will shut down the machine if these are violated. Hence, there is a limit in practice to the size of signal that can be injected, but the limit depends on the rate of change in the signal rather than its magnitude. Results are presented for a typical milling machine both for a step input and for system identification using pseudo-white-noise input. The method is very simple to apply on a machine having the necessary incremental encoder cards in the feedback loop, since no extra hardware is required.
Kinematics and tip-over stability analysis for the mobile modular manipulator
Authors: Li Y , Liu Y
Published: April 2005

This paper presents a practical method to establish the kinematics model for the mobile modular manipulator. A tough issue is resolved by decomposing a given task into motions performed by both the manipulator and the mobile platform. A direct differentiation method is used to analyse the differential kinematics. Stability analysis of the mobile manipulator is performed to evaluate the possibility of tip-over; some stability criteria are established. Computer simulations are carried on a real mobile modular manipulator, and ideal results are received to show that the theoretical analysis is feasible and correct.
Highly viscous liquid flow in pipeline components
Authors: McNeil D A , Stuart A D
Published: April 2005

Water and an aqueous glycerine solution were used to obtain liquids with nominal viscosities of 1 and 550 mPa s. These fluids were used to obtain friction factors for pipe flows, discharge coefficients for orifice plates and nozzles, and loss coefficients for an abrupt enlargement, a nozzle, an orifice plate, and a globe valve in the Reynolds number range 10-200. Existing methods are shown to be adequate for the prediction of friction factors and discharge coefficients, but inadequate for the prediction of loss coefficients. Insight is given into the flow behaviour that is associated with the loss coefficients.
Synthesis and Characterization of Praseodymium Hydroxide Nanorods by a Hydrothermal Process
Authors: Zhao Jie , Chen Weixiang , Yu Guiyan , Li Xiang , Zheng Yifan , Xu Zhude
Published: April 2005

Pr(OH)3 nanorods with 12–30 nm in diameter and 30–300 nm in length were prepared by a hydrothermal process. The as-synthesized product was characterized by XRD, TEM, and TG-DTA. The results showed that the nanorods are highly crystallized hexagonal structure and stable in the low temperature. The mechanism for the hydrothermal synthesis of Pr(OH)3 nanorods was discussed.
Nonrelativistic limit of Klein-Gordon-Maxwell to Schrödinger-Poisson
Authors: Bechouche Philippe , Mauser Norbert J. , Selberg Sigmund
Published: April 2005

We prove that in the nonrelativistic limit c → ∞, where c is the speed of light, solutions of the Klein-Gordon-Maxwell system on [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="01i" /] converge in the energy space C ([0, T ]; H 1 ) to solutions of a Schrödinger-Poisson system, under appropriate conditions on the initial data. This requires the splitting of the scalar Klein-Gordon field into a sum of two fields, corresponding, in the physical interpretation, to electrons and positrons. The proof relies on bilinear spacetime estimates related to the Klainerman-Machedon estimates, but taking into account the variation of the parameter c . A crucial fact is that the system has a null form structure in Coulomb gauge, as proved by Klainerman-Machedon.
Twisted genus bounds for subvarieties of generic hypersurfaces
Authors: Clemens Herbert , Ran Ziv
Published: April 2005

We prove some lower bounds on certain twists of the canonical bundle of a subvariety of a generic hypersurface in projective space. In particular we prove that the generic sextic threefold contains no rational or elliptic curves and no nondegenerate curves of genus 2.
A defect relation for holomorphic curves intersecting hypersurfaces
Authors: Ru Min
Published: April 2005

In 1933, H. Cartan proved a defect relation Σ q j =1 δ f ( H j ) ≤ n + 1 for a linearly nondegenerate holomorphic curve f : [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="01i" /] and hyperplanes H j , 1 ≤ j ≤ q , in [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="02i" /] in general position. This paper extends it to holomorphic curves intersecting hypersurfaces. In 1979, B. Shiffman conjectured that if f : [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="03i" /] is an algebraically non-degenerate holomorphic map, and D 1 , . . . , D q are hypersurfaces in [inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="04i" /] in general position, then Σ q j =1 δ f ( D j ) ≤ n + 1. This paper proves this conjecture.
Europe Moves Eastward: Consolidating Free Government in the New EU
Authors: Pehe Jiri
Published: April 2005

Abstract: The European Union has played a crucial role in the process of democratic consolidation in new democracies in Eastern Europe. The promise of membership has encouraged political moderation. Efforts to meet the EU’s membership criteria have significantly accelerated the modernization of institutions, the introduction of the rule of law, and the building of a transparent market economy. Even debates in candidate countries about the EU’s “democratic deficit” have been helpful with regard to understanding democracy. However, the EU’s role notwithstanding, internalizing democratic values values will take some time in societies deeply marked by decades of communist rule.
Misunderstood
Authors: Mallette Karla
Published: April 2005

The article argues the elasticity and continuing relevance of philology, and orientalist philology in particular, by considering two textual threads where philology and orientalism intersect. It reads twentieth century scholarship on a medieval Andalusian poetic form, the muwashshaha, against the genealogy of a modern text that negotiates between Arabic and western cultural spheres ? the blues standard ?(Don?t Let Me Be) Misunderstood? ? in order to evaluate philologists? responses to the medieval past and to the need to explicate and defend the relevance of the philological project to modernity. In particular, it engages the peculiar difficulties that face orientalist philology in the present moment, and contributes to the construction of a self-conscious philology able to articulate its relevance both to contemporary intellectual history and to its own disciplinary history.
From Butyribacterium to E. coli : An Essay on Unity in Biochemistry
Authors: Friedmann Herbert Claus
Published: April 2005

New ideas in science frequently arise from neglected or
distorted antecedents.This essay deals with the idea of biochemical
unity, encapsulated in Jacques Monod's well-known phrase, dating from
1954: "Anything found to be true of E. coli must also be true of
elephants." An earlier version of this phrase,—"From the elephant
to butyric acid bacterium—it is all the same!"—was coined in
1926 by the Dutch microbiologist Albert Jan Kluyver. In that year Kluyver
and his associate Hendrick Jean Louis Donker published a celebrated
paper, "Unity in Biochemistry."The concept of biochemical unity had many
antecedents, but these had never caught on. The Kluyver-Donker paper has
often been regarded to provide a boost to biochemical and especially to
microbiological thinking. Its interpretations and misinterpretations
represent an encapsulated history of biochemistry. The present paper
examines the history of the concept of biochemical unity from before
to beyond Kluyver, investigates the two "elephant" phrases and their
possible relationships, and ends with a discussion of the attractiveness
of unifying ideas in science.
Good Fences Make Bad Libraries: Rethinking Binary Constructions of Employment in Academic Libraries
Authors: Jones Phillip J , Stivers James
Published: April 2005

Academic libraries segregate their personnel into
professional and supportive categories almost exclusively on the
basis of the American Library Association's (ALA) accredited master's
degree. This article surveys the professional discourses of academic
librarians and adopts a critical theory methodology to critique this
practice. The authors recommend a refined classification of personnel
without repudiating professionalism.
Key Concepts: Endophenotypes
Authors: Glannon Walter
Published: April 2005

Endophenotypes are an exciting and important area of research
in genetically complex psychiatric diseases. They are biological
markers between genotype and external phenotype that may indicate
susceptibility to or manifest as early signs of a wide range of mental
disorders. Identifying endophenotypes can enable researchers to tease
apart the biological components of psychiatric diseases and thereby
gain a better understanding of them. They may lead to more accurate
prediction and to more effective prevention and treatment. Endophenotypes
also have implications for the philosophy of mind and the ethics of
informed consent.
The Froebellious Child in Catherine Sinclair's Holiday House
Authors: Rudd David
Published: April 2005

While some critics celebrate Catherine Sinclair's Holiday House (1839) for its innovative playfulness, others have drawn attention to its underlying didacticism, especially its formulaic, death-bed ending. Rudd argues that the book has a more overarching unity and addresses different concepts of child rearing. In contrast to the over-zealous corporal punishment and utilitarian fact cramming, the ideas of educationalists, such as Friedrich Froebel, are promoted. In this conception, children are given a protected space in which to grow, where the excesses of the carnivalesque can be indulged, which are, ultimately, a reflection of a benevolent Christianity.
Helen Hunt Jackson's Nelly's Silver Mine : A Lost Treasure Reclaimed
Authors: West Mark I
Published: April 2005

Helen Hunt Jackson is best remembered as an author of adult books, most notably Ramona, her 1884 novel about the plight of California Mission Indians. She also wrote several children's books including Nelly's Silver Mine: A Story of Colorado Life (1878). Although largely unknown today, it is an innovative novel that should appeal to modern readers interested in early Western literature as all as those intrigued to its strong female protagonist.
Speciation and Quantification of Thiols by Reversed-Phase Chromatography Coupled with On-Line Chemical Vapor Generation and Atomic Fluorescence Spectrometric Detection: Method Validation and Preliminary Application for Glutathione Measurements in Human Whole Blood
Authors: Bramanti Emilia , Vecoli Cecilia , Neglia Danilo , Pellegrini Maria Paola , Raspi Giorgio , Barsacchi Renata
Published: April 2005

Background: We developed a sensitive, specific method for the low–molecular-mass thiols cysteine, cysteinylglycine, glutathione, and homocysteine and validated the method for measurement of glutathione in blood.

Methods: The technique was based on reversed-phase chromatography (RPC) coupled on line with cold vapor generation atomic fluorescence spectrometry (CVGAFS). Thiols were derivatized before introduction on the column by use of a p-hydroxymercuribenzoate (PHMB) mercurial probe and separated as thiol-PHMB complexes on a Vydac C4 column. Postcolumn on-line reaction of derivatized thiols with bromine allowed rapid conversion of the thiol-PHMB complexes to inorganic mercury with recovery of 100 (2)% of the sample. HgII was selectively detected by atomic fluorescence spectrometry in an Ar/H2 miniaturized flame after sodium borohydride reduction to Hg0.

Results: The relationship between thiol-PHMB complex concentration and peak area (CVGAFS signal) was linear over the concentration range 0.01–1400 μmol/L (injected). The detection limits were 1, 1, 0.6, and 0.8 nmol/L for cysteine, cysteinylglycine, homocysteine, and glutathione in the injected sample, respectively. The CVs for thiols were 1.5%–2.2% for calibrator solutions and 2.1% and 3.0% for real samples. The RPC-CVGAFS method allowed speciation of glutathione (reduced and oxidized) in human whole blood from healthy donors and from the coronary sinus of patients with idiopathic dilated cardiomyopathy during and after chronotropic stress.

Conclusion: The RPC-CVGAFS method could be used to measure reduced and oxidized glutathione in human whole blood as disease biomarkers.
A 24-year Retrospective Study of Bone Growth After Implant Placement
Authors: Roberts Ralph A.
Published: April 2005

This study quantifies the changes in bone height noted in the body of the edentulous mandibles when the load of the complete denture is born by an RA Ramus Frame Implant (Pacific Implant, Rio Dell, Calif). Eighty-three patients with implants were followed for 3 to 24 years. Pre- and postoperative panoramic films were taken and again at each succeeding 5-year follow-up. The results of the bone changes were gathered retrospectively and calculated. The data revealed a significant increase in bone height from 4.413 to 13 mm and statistically significant P values of .0003 were determined. The growth of bone appears to be influenced by the design of the posterior feet, dominant chewing side, and a range of extreme atrophy from 5.9 mm to 15 mm. Also, the previously lost anatomical structures appear to repair, such as the luman of the mental foramen and the superior wall over the inferior alveolar canal. All mandibles were loaded postoperatively with an appliance having cutting bars and porcelain teeth or just porcelain teeth in both appliances.
One-Piece Root-Form Implants: A Return to Simplicity
Authors: Hahn Jack
Published: April 2005

Immediately loaded 1-piece dental implants were a standard treatment modality more than 30 years ago and, on occasion, resulted in excellent clinical successes. However, this technology also became associated with significant failure rates and fell out of favor. Since then, understanding of the site requirements and placement procedures necessary to ensure primary stability have advanced considerably. Implant designs and surface treatments also have evolved. In light of this greater understanding, a 1-piece root-form implant system has been developed. This article describes 4 clinical cases in which use of the new system was employed. In each case, the results included excellent stability, esthetics, and patient satisfaction.
Effects of Dissolved Calcium and Phosphorous on Osteoblast Responses
Authors: Ma S. , Yang Y. , Carnes D. L. , Kim K. , Park S. , Oh S. H. , Ong J. L.
Published: April 2005

The dissolution behavior of hydroxyapatite (HA) and its effect on the initial cellular response is of both fundamental and clinical importance. In this study, plasma-sprayed HA coatings were characterized by X-ray diffraction and Fourier transform infrared spectroscopy (FTIR). Calcium (Ca) and inorganic phosphorous (Pi) ions released from plasma-sprayed HA coatings within 3 weeks were measured by flame atomic absorption and colorimetrically molybdenum blue complex, respectively. To investigate the effect of dissolution of HA coatings on osteoblast response, additional Ca and Pi were added into the cell culture media to simulate the dissolution concentrations. Human embryonic palatal mesenchyme cells, an osteoblast precursor cell line, were used to evaluate the biological responses to enhanced Ca and Pi media over 2 weeks. Osteoblast differentiation and mineralization were measured by alkaline phosphatase–specific assay and 1,25 (OH)2 vitamin D3 stimulated osteocalcin production. The coatings exhibited an HA-type structure. FTIR indicated the possible presence of carbonates on the coatings. A dissolution study indicated a continual increase in Ca and Pi over time. In the cell culture study, enhanced osteoblast differentiation occurred in the presence of additional Ca concentration in the cell culture media. However, additional Pi concentration in the cell culture media was suggested to slow down osteoblast differentiation and mineralization.
Antral Membrane Balloon Elevation
Authors: Soltan Muna , Smiler Dennis G.
Published: April 2005

Many edentulous posterior maxilla are found to be encumbered by alveolar resorption and increased pneumatization of the sinus. These factors limit the quantity and quality of bone necessary for successful implant placement in these areas. One solution is to use shorter implants, but this often results in an unfavorable crown-root ratio. To create an improved environment in such regions, the classic sinus floor elevation with bone augmentation is a well-accepted technique. However, when the edentulous area is limited to a zone between 1 and 2 teeth, lifting the membrane becomes difficult and may subject it to iatrogenic injury. The antral membrane balloon elevation technique, which is introduced in this preliminary report, is a modification of the currently used sinus lift. It elevates the membrane easily and makes the antral floor accessible for augmentation with grafting materials.
Base‐Modified Oligodeoxyribonucleotides: Using Pyrrolo[2,3‐d]pyrimidines to Replace Purines
Authors: Seela Frank , Peng Xiaohua
Published: April 2005

Phosphoramidites are first synthesized from suitably protected 7‐deazapurine 2′‐deoxyribonuclosides that have halogen or alkynyl subsituents at the 7 position. Oligonucleotides containing 7‐deazapurines (pyrrolo[2,3‐d]pyrimidines) in place of the canonical nucleobases are then prepared by solid‐phase synthesis. These oligonucleotides are subsequently allowed to hybridize, and the stabilities of the resulting duplexes are determined. Comparison of Tm values indicates that the presence of 7‐halo or 7‐alkynyl substituents increases duplex stability relative to duplexes involving oligonucleotides that contain the corresponding parent purines.
DNA Microarray Preparation by Light‐Controlled In Situ Synthesis
Authors: Beier Markus , Hoheisel Jörg D.
Published: April 2005

This unit describes the in situ synthesis of DNA microarrays using a light‐controlled process. In a highly parallel fashion, multiple oligonucleotide probes are created from scratch on a glass support using phosphoramidite building blocks carrying a photolabile protecting group. Spatial resolution is achieved by carefully controlling the illumination of defined spots on the glass substrate, on which the oligonucleotide probes are synthesized using straightforward phosphoramidite chemistry.
Isolation of Melanosomes
Authors: Watabe Hidenori , Kushimoto Tsuneto , Valencia Julio C. , Hearing Vincent J.
Published: April 2005

The methods used to purify early and late melanosomes are detailed. These methods include the use of highly pigmented cells to maximize recovery and the use of various sucrose density gradients to separate melanosome fractions based on their density (which is determined in large part by the amount of dense melanin pigment that they contain). Early melanosomes lacking pigment must be further purified using free‐flow electrophoresis.
Human Mutation Databases
Authors: Horaitis Ourania , Cotton Richard G.H.
Published: April 2005

The first part of this unit compares general and locus‐specific mutation databases. The second section deals with submitting data. The third part provides guidance for accessing mutation data. The final section offers advice on database construction.
Using the Arabidopsis Information Resource (TAIR) to Find Information About Arabidopsis Genes
Authors: Reiser Leonore , Rhee Seung Yon
Published: April 2005

The Arabidopsis Information Resource (TAIR; http://www.arabidopsis.org) is a comprehensive Web resource of Arabidopsis biology for plant scientists. TAIR curates and integrates information about genes, proteins, gene expression, mutant phenotypes, biological materials such as DNA and seed stocks, genetic markers, genetic and physical maps, biochemical pathways, genome organization, images of mutant plants and protein sub‐cellular localizations, publications, and the research community Data in TAIR are extensively interconnected and can be accessed through a variety of Web‐based search and display tools. This unit primarily focuses on some basic methods for searching, browsing, visualizing, and analyzing information about Arabidopsis genes. Gene expression data from microarrays is a recent addition to the database and methods for accessing these data are also described. Two pattern identification programs are described for mining TAIR's unique Arabidopsis sequence data sets. We also describe how to use AraCyc for mining plant metabolic pathways.
Liquid–solid mass transfer in a three‐phase stationary catalytic basket reactor
Authors: Mitrovic Marijana , Pitault Isabelle , Forissier Michel , Simoens Serge , Ronze Didier
Published: April 2005

Measurements of the liquid–solid mass transfer coefficient kS were performed in a three‐phase multiple impeller and stationary catalytic basket reactor, called a Robinson–Mahoney reactor. Local coefficients were determined using naphtol particle dissolution in water and n‐heptane with or without gas flow. Experiments have shown that local coefficients kS loc depend on the particle position in the basket, agitation speed, and liquid properties. A correlation linking kS to liquid velocity was established in a reactor simulating hydrodynamics in a piece of catalytic basket. Liquid velocity values were validated using a particle image velocimetry technique in a Robinson–Mahoney reactor, using water. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Simultaneous optimal configuration, design and operation of batch distillation
Authors: Low K. H. , Sørensen E.
Published: April 2005

A methodology for simultaneous determination of optimal batch distillation configuration, design and operation is presented. The configuration design methodology utilizes a mixed integer dynamic optimization (MIDO) formulation approach, where the optimal batch distillation system is obtained automatically, based on its maximum overall profitability for a given separation duty. Using rigorous models, the MIDO problem is solved using a practical stochastic solution approach of genetic algorithm and penalty function. The feasibility of this methodology is demonstrated for both binary and multicomponent separation scenarios. In the binary separation case study, the effect of feed composition for different binary mixtures on the optimal configurations, that is, regular vs. inverted columns, is investigated and discussed. The regular column was found to be more profitable for feeds with a high fraction of the light component, whereas the inverted column is optimal for heavier feeds. The optimality of a particular configuration over another is, however, case study specific, depending on, for example, how easy the mixture is to separate. In the multicomponent separation case study, the results obtained highlight the superiority of the multivessel configuration over the regular and inverted configurations. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Isothermal crystallization of metallocene‐based propylene/α‐olefin copolymers
Authors: Xu Jun‐Ting , Zhang Yu‐Jin , Guan Fang‐Xiao , Fan Zhi‐Qiang
Published: April 2005

Isothermal crystallization and subsequent melting behavior of two propylene/hexene‐1 copolymers and two propylene/octene‐1 copolymers prepared with metallocene catalyst were investigated. It is found that γ‐modification is predominant in all copolymers. The Avrami exponent shows a weak dependency on comonomer content and comonomer type. At higher crystallization temperatures (Tc) the crystallization rate constant changes more rapidly with Tc and the crystallization half‐time substantially increases. Double melting peaks were also observed at high Tc, which is attributed to the inhomogeneous distribution of comonomer units along the polymer chains and the existence of crystals with different lamellar thicknesses. The equilibrium melting temperatures (T) of the copolymers were obtained by Hoffman–Weeks extrapolation. It was found that the T decreases with increasing comonomer content, but are independent of comonomer type, implying that comonomer units are excluded from the crystal lattice. Dilation of the crystal lattice was also observed, which depends on crystallization, comonomer content, and comonomer type. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 240–247, 2005
Synthesis and characterization of functionalized polymer latex particles through a designed semicontinuous emulsion polymerization process
Authors: Ding Tianhua , Daniels Eric S. , El‐Aasser Mohamed S. , Klein Andrew
Published: April 2005

Monodispersed noncarboxylated and carboxylated poly(n‐butyl methacrylate‐co‐n‐butyl acrylate) latices were synthesized with a well‐defined semicontinuous emulsion polymerization process. A modified theory to correlate the polymerization rate to the instantaneous conversion of the monomer or comonomer mixture was developed. The resulting equation was used to determine the maximum polymerization rate only below or equal to which the polymerization could be operated in the highly monomer‐starved regime, which corresponded to an instantaneous conversion of 90% or greater. Experimental data from reaction calorimetry supported that the polymerization was under highly monomer‐starved conditions when the model latices were synthesized with the modified model. The estimation of the average number of free radicals per latex particle(n̄) during the feeding stage revealed that n̄ was as high as 1.4 in the actual polymerization, which showed that the original selection of 0.5 as the n̄ value was not accurate in the developed model. From the conductimetric titration experiments, we found that most of the carboxyl groups from the methacrylic acid (MAA) were buried inside the latex particles, and the surface carboxyl group coverage increased as the MAA concentration in the comonomer feed increased. The glass‐transition temperatures of the synthesized polymers were close to the designed value from the Pochan equation, and only one glass transition was observed in the polymer samples in the differential scanning calorimetry measurements, indicating a homogeneous copolymer composition in the functionalized shell. Particle size characterization and transmission electron microscopy confirmed the uniformity in the latex particle size. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 248–256, 2005
Study of reaction kinetics of epoxy and a nickel(II) complex using dynamic DSC technique
Authors: Ghaemy M. , Omrani A. , Rostami A. A.
Published: April 2005

The curing reaction kinetics of an epoxy based on the diglycidyl ether of bisphenol A (DGEBA) with an inorganic complex based on nickel(II) chelate with ethylenediamine (en) as a ligand were studied using DSC in dynamic mode. The complex curing agent was synthesized and characterized by the elemental analysis, FT‐IR, and ICP‐Plasma techniques. Thermal dissociation behavior of curing agent was also studied using thermogravimetric (TG) analysis in isolated form. Three kinetic models, Kissinger, Ozawa‐Flynn‐Wall, and Expanded Freeman‐Carrole, were used to determine the kinetic parameters. The effect of hardener concentration on the kinetic parameters and the shape of DSC thermograms of the DGEBA/Ni(en)3Br2 system were investigated. Finally, the previous proposed mechanism by another researcher was used to explain the DSC data in detail. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 265–271, 2005
Cationic photopolymerization of oxetane‐functionalized hyperbranched polymers
Authors: Sangermano M. , Di Gianni A. , Malucelli G. , Roncuzzi C. , Priola A. , Voit B.
Published: April 2005

An aliphatic–aromatic pehenolic hyperbranched starting material (HBP‐OH) with phenolic end groups was 85% functionalized by a Mitsunobu reaction with oxetane groups (OXT‐HBP). This new hyperbranched polyester was used, at a concentration of 5–20 wt %, as an additive for the cationic photopolymerization of a commercial oxetane‐based resin, 4,4′‐bis[(3‐ethyl‐3‐ethyl‐3‐oxetanyl) methoxymethyl]biphenyl (OXBP). HBP‐OXT acted as a multifunctional crosslinker, copolymerizing with the oxetane ring of the OXBP resin, reacting through chain transfer with the remaining phenolic OH groups, or doing both. The result was an increase in the glass‐transition temperature due to the increase in the crosslinking density. An increase in the weight residue at a high temperature was found in the presence of HBP‐OXT and was attributed to the presence of phenolic groups, which are commonly used as antioxidant additives. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 293–299, 2005
Morphology and properties of thermoplastic polyurethane composites incorporating hydrophobic layered silicates
Authors: Finnigan Bradley , Martin Darren , Halley Peter , Truss Rowan , Campbell Kayleen
Published: April 2005

Polyurethane (PU) composites incorporating Cloisite 15A (15A) were prepared via melt compounding and solvent casting. The melt‐compounded composites had better dispersion and a smaller silicate stack size as a result of the higher shear forces associated with twin‐screw extrusion. The PU microphase separation and hard domain order were greater in the melt‐processed materials. At the concentrations of 15A employed in this study (≤7 wt %), the filler did not have an observable effect on the microphase texture of either the solvent‐ or melt‐processed PU. The tensile properties of the melt‐compounded materials were lower than those of their solvent‐cast counterparts because of thermal degradation. The solvent‐cast composite containing a 3 wt % loading of 15A displayed improved tensile strength and elongation, primarily because of plasticization by the silicate organic treatment. The addition of layered silicates with high aspect ratios increased the hysteresis and permanent set of this PU elastomer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 300–309, 2005
Comparative study of cellulose isolated by totally chlorine‐free method from wood and cereal straw
Authors: Sun J. X. , Xu F. , Geng Z. C. , Sun X. F. , Sun R. C.
Published: April 2005

Highly purified cellulose preparations were obtained by pretreatment of dewaxed barley straw, oil palm frond fiber, poplar wood, maize stems, wheat straw, rice straw, and rye straw with 2.0% H2O2 at 45°C and pH 11.6 for 16 h, and sequential purification with 80% acetic acid–70% nitric acid (10/1, v/v) at 120°C for 15 min. The purified cellulose obtained was relatively free of bound hemicelluloses (2.3–3.2%) and lignin (0.4–0.6%) and had a yield of 35.5% from barley straw, 39.6% from oil palm frond fiber, 40.8% from poplar wood, 36.0% from maize stems, 34.1% from wheat straw, 23.4% from rice straw, and 35.8% from rye straw. The weight‐average molecular weights of the purified cellulose ranged from 39,030 to 48,380 g/mol. The thermal stability of the purified cellulose was higher than that of the corresponding crude cellulose. In comparison, the isolated crude and purified cellulose samples were also studied by Fourier transform IR and cross‐polarization/magic‐angle spinning 13C‐NMR spectroscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 322–335, 2005
Functional copolymers of p‐cumyl phenyl methacrylate and glycidyl methacrylate: Synthesis, characterization, and reactivity ratios
Authors: Ratnaprabha Khisti , Daliya P. K.
Published: April 2005

Free‐radical polymerization of p‐cumyl phenyl methacrylate (CPMA) was performed in benzene using bezoyl peroxide as an initiator at 80°C. The effect of time on the molecular weight was studied. Functional copolymers of CPMA and glycidyl methacrylate (GMA) with different feed ratios were synthesized by free‐radical polymerization in methyl ethyl ketone at 70°C, and they were characterized by FTIR and 1H‐NMR spectroscopy. The molecular weights and polydispersity indexes of the polymers and copolymers were determined by gel permeation chromatography. The copolymer composition was determined by 1H‐NMR. The glass‐transition temperature of the polymer and the copolymers was determined by differential scanning calorimetry. The reactivity ratios of the monomers were determined by the Fineman–Ross and Kelen–Tudos methods. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 336–347, 2005
Morphological studies of polypropylene–nanoclay composites
Authors: Mani Gopinath , Fan Qinguo , Ugbolue Samuel C. , Yang Yiqi
Published: April 2005

Polypropylene–clay nanocomposites were prepared by a solution technique and a subsequent melt‐mixing process. A titanate coupling agent was used to improve the compatibility of the nanoclay particles with the polypropylene. The dispersion of the nanoclay particles in polypropylene was studied with X‐ray diffraction (XRD) and transmission electron microscopy (TEM). An increased d‐spacing value of the clay particles in the nanocomposites was observed, and it was compared with the values of as‐mined (pristine) and as‐received (organophilic) clay particles. The number of intercalated layers in a single clay crystallite was determined to be 4, and the number was confirmed with XRD data and TEM images. On the basis of the Daumas–Herold model (which is widely used for graphite intercalation compounds), the stage 2 and stage 3 structures of montmorillonite particles in polypropylene were recommended. A study on the stage structure suggested a way of determining the presence of polymer molecules in the clay galleries. The results confirmed the existence of single‐layered platelets with improved dispersion in polypropylene. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 218–226, 2005
Effect of hypochlorite concentration on properties of posttreated outer‐skin ultrafiltration membranes spun from cellulose acetate/poly(vinyl pyrrolidone) blends
Authors: Qin Jian‐Jun , Cao Yi‐Ming , Li Ying
Published: April 2005

An outer‐skin hollow‐fiber ultrafiltration (UF) membrane was spun from a new dope solution containing cellulose acetate (CA)/poly(vinyl pyrrolidone) (PVP 360K)/N‐methyl‐2‐pyrrolidone (NMP)/water using a wet‐spinning technique. The as‐spun fibers were posttreated with a hypochlorite solution over a range of concentrations for a fixed period of 24 h. The experimental results showed that the pure water flux of the treated membrane increased with increasing hypochlorite concentration. The treated membrane experienced an increased fouling tendency with increasing hypochlorite concentration because the hydrophilicity of the treated membrane decreased as a result of the removal of PVP contents in the membrane matrix after hypochlorite treatment. SEM images revealed that the membrane had an outer dense skin, a porous inner surface, and a spongelike structure, which confirmed that addition of PVP favored the suppression of macrovoids in the membrane. The membrane pore size could be significantly increased when the hypochlorite concentration reached 200 mg/L. It was concluded that hypochlorite treatment provided an additional option to easily alter the pore size of UF membranes. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 227–231, 2005
Curing of low level melamine‐modified urea‐formaldehyde particleboard binder resins studied with dynamic mechanical analysis (DMA)
Authors: Young No B. , Kim Moon G.
Published: April 2005

Effects of resin formulation, catalyst, and curing temperature were studied for particleboard binder‐type urea‐formaldehyde (UF) and 6 ∼ 12% melamine‐modified urea‐melamine‐formaldehyde (UMF) resins using the dynamic mechanical analysis method at 125 ∼ 160°C. In general, the UF and UMF resins gelled and, after a relatively long low modulus period, rapidly vitrified. The gel times shortened as the catalyst level and resin mix time increased. The cure slope of the vitrification stage decreased as the catalyst mix time increased, perhaps because of the deleterious effects of polymer advancements incurred before curing. For UMF resins, the higher extent of polymerization effected for UF base resin in resin synthesis increased the cure slope of vitrification. The cure times taken to reach the vitrification were longer for UMF resins than UF resins and increased with increased melamine levels. The thermal stability and rigidity of cured UMF resins were higher than those of UF resins and also higher for resins with higher melamine levels, to indicate the possibility of bonding particleboard with improved bond strength and lower formaldehyde emission. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 377–389, 2005
Studies on the intermolecular structural heterogeneity of a propylene‐ethylene random copolymer using preparative temperature rising elution fractionation
Authors: Liu Yonggang , Bo Shuqin , Zhu Yejuan , Zhang Wenhe
Published: April 2005

The intermolecular structural heterogeneity of a propylene‐ethylene random copolymer was studied by preparative temperature rising elution fractionation combined with GPC, 13C‐NMR, differential scanning calorimetry, and wide‐angle X‐ray diffraction analysis of the obtained fractions. The isotacticity of fractions increased with increasing elution temperature, and the ethylene content decreased monotonously. Fitting of the obtained comonomer triad sequences by Bernoullian and first‐order Markovian statistical models indicated that lower isospecific active sites are more active toward ethylene. The isolated ethylene unit disrupted the crystallizable isotactic sequence and lowered the crystallizability of the polypropylene chain. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 232–239, 2005
Propagation through conical crossings: An asymptotic semigroup
Authors: Lasser Caroline , Teufel Stefan
Published: April 2005

We consider the standard model problem for a conical intersection of electronic surfaces in molecular dynamics. Our main result is the construction of a semi‐group in order to approximate the Wigner function associated with the solution of the Schrödinger equation at leading order in the semiclassical parameter. The semigroup stems from an underlying Markov process that combines deterministic transport along classical trajectories within the electronic surfaces and random jumps between the surfaces near the crossing. Our semigroup can be viewed as a rigorous mathematical counterpart of so‐called trajectory surface hopping algorithms, which are of major importance in molecular simulations in chemical physics. The key point of our analysis, the incorporation of the nonadiabatic transitions, is based on the Landau‐Zener type formula of Fermanian‐Kammerer and Gérard10 for the propagation of two‐scale Wigner measures through conical crossings. © 2005 Wiley Periodicals, Inc.