bluuebunny/crossref_metadata_2025 huggingface dataset:
New Organic Nonlinear Optical Polyene Crystals and Their Unusual Phase Transitions
Authors: Kwon O‐P. , Kwon S.‐J. , Jazbinsek M. , Choubey A. , Gramlich V. , Günter P.
Published: June 2007

A series of new nonlinear optical chromophores based on configurationally locked polyenes (CLPs) with chiral pyrrolidine donors are synthesized. All CLP derivatives exhibit high thermal stability with decomposition temperatures Td at least >  270 °C. Acentric single crystals of enantiopure D‐ and L‐prolinol‐based chromophores with a monoclinic space group P21 exhibit a macroscopic second‐order nonlinearity that is twice as large than that of analogous dimethylamino‐based crystal. This is attributed to a strong hydrogen‐bonded polar polymer‐like chain built by these molecules, which is aligned along the polar crystallographic b‐axis. Five α‐phase CLP crystals with different donors grown from solution exhibit a reversible or irreversible thermally induced structural phase transition to a β‐phase. These phase transitions are unusual, changing the crystal symmetry from higher to lower at increasing temperatures, for example, from centrosymmetric to non‐centrosymmetric, enhancing their macroscopic second‐order nonlinear optical properties.
A Smart Supramolecular Hydrogel Exhibiting pH‐Modulated Viscoelastic Properties
Authors: Shi N. E. , Dong H. , Yin G. , Xu Z. , Li S. H.
Published: June 2007

The macroscopic viscoelastic properties of a physical hydrogel are reversibly modulated by tuning the microscopic hydrogen‐bonding interactions with pH. The hydrogel forms at a rather low concentration of the multi‐pyridyl‐based gelator, N, N′, N″‐tris(3‐pyridyl)trimesic amide. The yield stress of the hydrogel is greatly enhanced from 10 to 769 Pa by changing the pH from 7.0 to 5.0. At pH 7.0, the amide molecules are assembled into an ordered structure as a result of the hydrogen bonds between the amide N–H bond and the nitrogen on the pyridyl group (N–H…Py). Fourier transform (FT) IR spectroscopy indicates that hydrogen bonds of N–H…Py are partially broken because the pyridyl groups are partly protonated at pH 5.0. This condition leads to a highly branched and homogeneous fibrillar network, which is confirmed by X‐ray diffraction (XRD) measurements and field‐emission scanning electron microscopy (FESEM) images. Highly branched fibrillar networks create more compartments and greatly increase the interfacial tension that is required to hold the solvent in the gel, thereby increasing the yield stress to 769 Pa. By further increasing the acidity of the hydrogel to pH < 3.0, the gel becomes a sol. Both the change in the viscoelastic properties and the sol–gel transition are reversible and controllable in the material.
White Electroluminescence from a Single‐Polymer System with Simultaneous Two‐Color Emission: Polyfluorene Blue Host and Side‐Chain‐Located Orange Dopant
Authors: Liu J. , Guo X. , Bu L. J. , Xie Z. Y. , Cheng Y. X. , Geng Y. H. , Wang L. X. , Jing X. B. , Wang F. S.
Published: June 2007

Four single polymers with two kinds of attachment of orange chromophore to blue polymer host for white electroluminescence (EL) were designed. The effect of the side‐chain attachment and main‐chain attachment on the EL efficiencies of the resulting polymers was compared. The side‐chain‐type single polymers are found to exhibit more efficient white EL than that of the main‐chain‐type single polymers. Based on the side‐chain‐type white single polymer with 4‐(4‐alkyloxy‐phenyl)‐7‐(4‐diphenylamino‐phenyl)‐2,1,3‐benzothiadiazoles as the orange‐dopant unit and polyfluorene as the blue polymer host, white EL with simultaneous orange (λmax = 545 nm) and blue emission (λmax = 432 nm/460 nm) is realised. A single‐layer device (indium tin oxide/poly(3,4‐ethylenedioxythiophene)/polymer/Ca/Al) made of these polymers emits white light with the Commission Internationale de l'Éclairage coordinates of (0.30,0.40), possesses a turn‐on voltage of 3.5 V, luminous efficiency of 10.66 cd A–1, power efficiency of 6.68 lm W–1, and a maximum brightness of 21 240 cd m–2.
GPC3 mutations in seven patients with Simpson–Golabi–Behmel syndrome
Authors: Sakazume Satoru , Okamoto Nobuhiko , Yamamoto Toshiyuki , Kurosawa Kenji , Numabe Hironao , Ohashi Yuko , Kako Yuko , Nagai Toshiro , Ohashi Hirohumi
Published: June 2007

We analyzed mutations of the GPC3gene in seven males with typical manifestations of Simpson–Golabi–Behmel syndrome (SGBS). Genomic DNA was PCR amplified for its all eight exons and exon–intron boundaries using designed set of primers, and PCR products were directly sequenced. All seven males studied had mutations: One patient had a large deletion spanning introns 6 and 7, four each had a C → T base substitution resulting in a stop codon formation in exons 2, 3, and 4, one had a single‐base insertion in exon 2, and the other had a six‐base deletion and a three‐base insertion in exon 3; all resulting in loss‐of‐function of the glypican‐3 protein. These results, together with previous studies of GPC3 mutations, indicate that there is no hot spot for GPC3 mutations or deletions in the patients with the syndrome. Also, no correlation has been noted between the location and nature of mutations and the phenotype of the patients studied, as is the case of the present study. © 2007 Wiley‐Liss, Inc.
Recurrence risk in de novo structural chromosomal rearrangements
Authors: Röthlisberger Benno , Kotzot Dieter
Published: June 2007

According to the textbook of Gardner and Sutherland [2004], the standard on genetic counseling for chromosome abnormalities, the recurrence risk of de novo structural or combined structural and numeric chromosome rearrangements is less than 0.5–2% and takes into account recurrence by chance, gonadal mosaicism, and somatic‐gonadal mosaicism. However, these figures are roughly estimated and neither any systematic study nor exact or evidence‐based risk calculations are available. To address this question, an extensive literature search was performed and surprisingly only 29 case reports of recurrence of de novo structural or combined structural and numeric chromosomal rearrangements were found. Thirteen of them were with a trisomy 21 due to an i(21q) replacing one normal chromosome 21. In eight of them low‐level mosaicism in one of the parents was found either in fibroblasts or in blood or in both. As a consequence of the low number of cases and theoretical considerations (clinical consequences, mechanisms of formation, etc.), the recurrence risk should be reduced to less than 1% for a de novo i(21q) and to even less than 0.3% for all other de novo structural or combined structural and numeric chromosomal rearrangements. As the latter is lower than the commonly accepted risk of approximately 0.3% for indicating an invasive prenatal diagnosis and as the risk of abortion of a healthy fetus after chorionic villous sampling or amniocentesis is higher than approximately 0.5%, invasive prenatal investigation in most cases is not indicated and should only be performed if explicitly asked by the parents subsequent to appropriate genetic counseling. © 2007 Wiley‐Liss, Inc.
Meckel syndrome in the Hutterite population is actually a Joubert‐related cerebello‐oculo‐renal syndrome
Authors: Boycott Kym M. , Parboosingh Jillian S. , Scott James N. , McLeod D. Ross , Greenberg Cheryl R. , Fujiwara T. Mary , Mah Jean K. , Midgley Julian , Wade Andrew , Bernier Francois P. , Chodirker Bernard N. , Bunge Martin , Innes A. Micheil
Published: June 2007

Meckel syndrome (MKS) is a rare lethal autosomal recessive disorder characterized by the presence of occipital encephalocele, cystic kidneys, fibrotic changes of the liver and polydactyly. Joubert syndrome (JS)‐related disorders (JSRDs) or cerebello‐oculo‐renal syndromes (CORS) are a group of recessively inherited conditions characterized by a molar tooth sign (MTS) on cranial MRI, a set of core clinical features (developmental delay/mental retardation, hypotonia, ataxia, episodic breathing abnormalities, abnormal eye movements) and variable involvement of other systems including renal, ocular, central nervous system, craniofacial, hepatic, and skeletal. A significant clinical overlap between MKS and JSRD/CORS has been recognized in the literature. We describe a group of 10 Hutterite patients, of which 7 had been previously diagnosed with MKS, with a JSRD. Clinical features include variable early mortality, cognitive handicap, a characteristic dysmorphic facial appearance, hypotonia, ataxia, abnormal breathing pattern, nystagmus, and MTS on MRI. Additional features include occipital encephalocele, posterior fossa fluid collections resembling Dandy–Walker malformation, hydrocephalus, coloboma, and renal disease. This JSRD is a recognizable dysmorphic syndrome characterized by hypertelorism, deep‐set eyes, down‐slanting palpebral fissures, ptosis, arched eyebrows with medial sparseness, square nasal tip, short philtrum with tented upper lip, open mouth with down‐turned corners, and posteriorly rotated low‐set ears. Renal disease is present in 70% of patients and is characterized by cystic kidneys, abnormalities in renal function and hypertension. Homozygous deletions of NPHP1 and the known loci for JS/JSRD and MKS were excluded by identity‐by‐descent mapping studies suggesting that this condition in the Hutterites represents yet another locus for a JSRD. © 2007 Wiley‐Liss, Inc.
Variable expressivity in Patau syndrome is not all related to trisomy 13 mosaicism
Authors: Hsu Hui‐Fang , Hou Jia‐Woei
Published: June 2007

Patau syndrome (trisomy 13) is very rare in live‐born babies. Individuals with this chromosomal syndrome have a short lifespan and are rarely seen beyond infancy. This study is aimed at the clinical spectrum, natural history, and survival of patients with trisomy 13. We reviewed the detailed data of 13 Patau syndrome live‐born babies. Among them two individuals were delivered from continuation of pregnancy even after prenatal diagnosis. The remaining 11 patients were born to younger mothers who did not undergo amniocentesis because no major anomalies except for cleft lip/palate were found on prenatal sonograms. The common features of Patau syndrome including the clinical triad (microphthalmia, cleft lip/palate, and polydactyly) and non‐cyanotic heart defects were always found in our series. However, certain serious central defects (holoprosencephaly, omphalocele, and single umbilical artery), which are easily recognized from prenatal sonogram, occurred less frequently than those stated in the literature. The median survival time was 95 days and was longer than that previously reported. There were two infants with trisomic mosaicism with different outcomes in both clinical spectrum and survival. Otherwise, we also found the increased recurrence risks of aneuploidy in two individuals, and the longest survivor (84 months) of non‐mosaic trisomy 13 in Taiwan. We thus suggest that long‐term survival in our series is strongly correlated with different expressivity after prenatal selection, in addition to cytogenetic mosaicism. Less associated anomalies such as polyhydramnios, oligohydramnios, intrauterine growth retardation, single umbilical artery, eye defects, holoprosencephaly, omphalocele, and polycystic kidney may contribute to their clinical courses. © 2007 Wiley‐Liss, Inc.
Core content and stability of n‐octadecane‐containing polyurea microencapsules produced by interfacial polymerization
Authors: Siddhan Periyasamy , Jassal Manjeet , Agrawal Ashwini K.
Published: June 2007

Microencapsulation of phase change material (PCM) n‐octadecane was carried out by interfacial polymerization technique using core and bulk monomers as toluene‐2,4‐diisocyanate (TDI) and diethylene triamine (DETA), respectively. Cyclohexane was used as the solvent for TDI and n‐octadecane, which formed the oil phase. The effect of encapsulation procedure, core‐to‐monomer ratio (CM ratio) and PCM‐to‐cyclohexane (PC) ratio was investigated on core content, encapsulation efficiency, and stability of microcapsules. Using a modified procedure, the core content was found to increase with the increasing CM ratio and reached a maximum at 3.7, while the encapsulation efficiency continuously decreased with the increasing CM ratio. Also the encapsulation efficiency was found to have a strong dependence on PC ratio and a maximum encapsulation efficiency of 92%, along with the core content of 70% was obtained with CM ratio of 3.7 along with the PC ratio of 6. The microcapsules were well shaped, i.e., round and regular, with narrow size distribution at these conditions. The PCM microcapsules were found to be stable to heat treatment at 150°C for 8 h. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Mechanical properties of polyurethane/montmorillonite nanocomposite prepared by melt mixing
Authors: Chun Byoung Chul , Cho Tae Keun , Chong Mi Hwa , Chung Yong‐Chan , Chen Jihua , Martin David , Cieslinski Robert C.
Published: June 2007

Nanocomposites from polyurethane (PU) and montmorillonite (MMT) were prepared under melt‐mixing condition, by a twin screw extruder along with a compatibilizer to enhance dispersion of MMT. MMT used in this study was Cloisite 25A (modified with dimethyl hydrogenated tallow 2‐ethylhexyl ammonium) or Cloisite 30B (modified with methyl tallow bis‐2‐hydroxyethyl ammonium). Maleic anhydride grafted polypropylene (MAPP) was used as the compatibilizer. XRD and TEM analysis demonstrated that melt mixing by a twin‐screw extruder was effective in dispersing MMT through the PU matrix. The PU/Cloisite 30B composite exhibited better interlayer separation than the PU/Cloiste 25A composite. Nanoparticle dispersion was the best at 1 wt % of MMT and improved with compatibilizer content for both composites. Properties of the composites such as complex viscosity and storage modulus were higher than that of a pure PU matrix and increased with the increase in MMT content, but decreased with the increase in compatibilizer content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Predominance of CD8+ T lymphocytes among periglomerular infiltrating cells and link to the prognosis of class III and class IV lupus nephritis
Authors: Couzi Lionel , Merville Pierre , Deminière Colette , Moreau Jean‐François , Combe Christian , Pellegrin Jean‐Luc , Viallard Jean‐François , Blanco Patrick
Published: June 2007

Objective

Recent studies have revealed a potential implication of CD8+ T lymphocytes in the pathogenesis of systemic lupus erythematosus (SLE) through their ability to induce tissue damage. The aim of the present study was to analyze the localization of CD8+ cells in the kidneys of patients with class III and class IV lupus nephritis and to establish correlations with histologic, biologic, and clinical features of SLE.

Methods

Twenty‐five consecutive SLE patients with class III or class IV lupus nephritis were enrolled. Phenotype analyses of blood lymphocytes and renal immunohistochemistry studies were performed.

Results

CD8+ T cells were the predominant kidney‐infiltrating subset of cells. The mean ± SD numbers of CD8+ T cells and CD4+ T cells were 66.2 ± 65.2/mm2 and 19.3 ± 29.4/mm2, respectively. There was a significant correlation between the percentage of blood CD3+,CD8+,DR+ cells and the total number of renal CD8+ T cells (r = 0.42, P = 0.039). Renal CD8+ T cell infiltration correlated well with the renal activity index (r = 0.63, P = 0.0007) and with high serum creatinine levels (r = 0.75, P = 0.0001). This CD8+ T cell infiltrate, which was predominantly in the periglomerular area, was correlated with cellular crescents and Bowman's capsule rupture and was associated with a poor response after conventional induction therapy.

Conclusion

CD8+ T lymphocytes infiltrate the periglomerular area in patients with severe (class III and class IV) lupus nephritis and are linked to a poor outcome after induction therapy. These results reveal a new potential effector pathway operant in lupus nephritis.
Sjögren's syndrome disease damage index and disease activity index: Scoring systems for the assessment of disease damage and disease activity in Sjögren's syndrome, derived from an analysis of a cohort of Italian patients
Authors: Vitali Claudio , Palombi Gianluigi , Baldini Chiara , Benucci Maurizio , Bombardieri Stefano , Covelli Michele , Del Papa Nicoletta , De Vita Salvatore , Epis Oscar , Franceschini Franco , Gerli Roberto , Govoni Marcello , Bongi Susanna Maddali , Maglione Wanda , Migliaresi Sergio , Montecucco Carlomaurizio , Orefice Maddalena , Priori Roberta , Tavoni Antonio , Valesini Guido
Published: June 2007

Objective

To develop valid instruments for the assessment of disease‐related damage and disease activity in Sjögren's syndrome (SS).

Methods

Data on 206 patients with primary SS were collected in 12 Italian centers. Each patient was scored by 1 investigator, on the basis of a global assessment of the degree of disease damage and disease activity. Patients judged to have active disease at the time of enrollment underwent a second evaluation after 3 months. Univariate and multivariate analyses were performed to select the clinical and serologic variables that were the best predictors of damage and of disease activity, and these variables were used to construct the Sjögren's Syndrome Disease Damage Index (SSDDI) and the Sjögren's Syndrome Disease Activity Index (SSDAI). The weight of each variable in the index was determined by the β coefficients in multivariate regression models. Scores obtained using the SSDDI and the SSDAI were compared with scores initially given by the investigators. Finally, a receiver operating characteristic (ROC) curve was used to determine the cutoff value in the SSDAI with the highest level of accuracy in identifying patients with a significant level of disease activity.

Results

A multivariate model with 9 variables was the best predictor of investigator scores of damage. The scores obtained using the SSDDI were closely correlated with investigator ratings (R = 0.760, P < 0.0001). A model composed of 11 variables was the best predictor of investigator scores of disease activity. The scores obtained using the SSDAI were strongly correlated with the investigator ratings both at the time of enrollment and 3 months after enrollment (R = 0.872, P < 0.0001, and R = 0.817, P < 0.0001, respectively). The differences between scores given by investigators at study enrollment and after 3 months, a measure of variation of disease activity over time, were also closely correlated with the differences calculated using the SSDAI (R = 0.683, P < 0.0001). The ROC curve analysis showed that patients with the highest level of disease activity could be identified on the basis of an SSDAI score of ≥5.

Conclusion

Our findings indicate that the SSDDI is an adequate instrument to objectively measure damage in patients with SS, and that the SSDAI is a valid tool to measure disease activity when used either as a single‐state index or as a transition index.
Impairment of the antifibrotic effect of hepatocyte growth factor in lung fibroblasts from African Americans: Possible role in systemic sclerosis
Authors: Bogatkevich Galina S. , Ludwicka‐Bradley Anna , Highland Kristin B. , Hant Faye , Nietert Paul J. , Singleton C. Beth , Feghali‐Bostwick Carol A. , Silver Richard M.
Published: June 2007

Objective

To compare the composition of cytokines in African American and Caucasian patients with systemic sclerosis (SSc; scleroderma) and in healthy individuals, particularly the expression and function of hepatocyte growth factor (HGF).

Methods

Bronchoalveolar lavage (BAL) fluid samples were analyzed using cytokine array techniques. HGF in plasma and cell culture medium samples was measured by enzyme‐linked immunosorbent assay. Connective tissue growth factor (CTGF), type I collagen expression, and c‐Met receptor phosphorylation were studied by immunoblotting.

Results

Overall greater expression of cytokines in BAL fluid from African American patients as compared with Caucasian patients was observed. Significant increases in HGF concentrations were detected in BAL fluid, plasma, and fibroblast culture medium from Caucasian SSc patients. In contrast, African American SSc patients did not demonstrate an increase in HGF. Recombinant HGF readily abolished CTGF expression and collagen accumulation in lung fibroblasts isolated from Caucasian SSc patients. Pretreatment of lung fibroblasts with neutralizing anti–c‐Met antibody abolished the effects of HGF on CTGF expression and collagen accumulation, suggesting that the antifibrotic activity of HGF is mediated via c‐Met receptor tyrosine kinase. Whereas recombinant HGF rapidly induced c‐Met receptor phosphorylation in lung fibroblasts from Caucasian patients, c‐Met receptor phosphorylation was significantly reduced in lung fibroblasts from African American subjects. Moreover, recombinant HGF failed to prevent CTGF expression and collagen accumulation in lung fibroblasts derived from African American subjects.

Conclusion

Ethnic differences exist in terms of antifibrotic HGF expression in lung fibroblasts derived from Caucasian and African American subjects. Reduced levels of HGF as well as a deficiency in c‐Met receptor function appear to be present in African American patients with SSc. These findings may explain in part the greater disease severity and worse prognosis observed in African Americans with SSc.
Association between serum vitamin D metabolite levels and disease activity in patients with early inflammatory polyarthritis
Authors: Patel Sanjeev , Farragher Tracey , Berry Jacqueline , Bunn Diane , Silman Alan , Symmons Deborah
Published: June 2007

Objective

Previous in vitro and animal studies have suggested that vitamin D, in particular, its metabolite 25‐hydroxyvitamin D (25[OH]D), may have immunomodulatory effects. To study further the potential immunomodulatory effects of vitamin D in humans, we explored the hypothesis that serum vitamin D metabolites may be inversely associated with current disease activity, severity, and functional disability in patients with early inflammatory polyarthritis (IP).

Methods

We studied 206 consecutive patients with IP who were enrolled in the Norfolk Arthritis Register between January 2000 and November 2003 inclusive. Patients were studied within 6 months of symptom onset. None of the patients was taking steroids, and all had received <6 weeks of disease‐modifying therapy. Associations between serum levels of 25(OH)D and 1,25‐dihydroxyvitamin D (1,25[OH]2D) at baseline and the swollen and tender joint counts, Health Assessment Questionnaire (HAQ) scores, C‐reactive protein (CRP) levels, and the Disease Activity Score 28‐joint assessment (DAS28) scores at baseline and 1 year were assessed.

Results

The median age at symptom onset was 59 years (range 20–88 years), with a median disease duration of 4 months. At baseline, there was an inverse relationship between 25(OH)D levels and the tender joint count, DAS28 score, and HAQ score. The only inverse relationship with 1,25(OH)2D was with the HAQ score. Each 10‐ng/ml increase in the level of 25(OH)D was associated with a decrease in the DAS28 score of 0.3 and in the CRP level of ∼25%. At 1 year, the only significant result was an inverse association between baseline vitamin D metabolite levels and the HAQ score; that is, those with higher metabolite levels had lower HAQ scores.

Conclusion

These data provide further support that vitamin D plays an immunomodulatory role in inflammatory arthritis. This association needs to be examined in other cohorts of patients with early IP, as well as in longitudinal studies. If confirmed, the clinical response to vitamin D supplementation should be examined in early IP.
National publication and citation comparisons
Authors: Narin Francis , Carpenter Mark P.
Published: June 2007

Indicators of national scientific activity have been derived from counts of 500,000 publications, and millions of citations, in 492 large and heavily cited scientific journals in seven major disciplines, six major countries, and a time span from 1965 to 1971. For 1972 the publication and citation counts covered 2143 journals. All of the citation data, and much of the publication data, were from journals covered by the Science Citation Index (SCI). The publication counts indicate clear first rank position for the U.S. in scientific publications, followed at a significant distance by the Soviet Union. Far below the U.S. and U.S.S.R. are the United Kingdom and Germany, followed by Japan and France. The national publication rankings vary widely from discipline to discipline, with Soviet chemistry high, physics moderate and biology low. The U.S. is the most highly cited country, followed by the U.K.; Germany and Japan are at a middle level, with French and Soviet publications the least heavily cited.
On the equivalence of boolean and weighted searching based on the convertibility of query forms
Authors: Angione Pauline V.
Published: June 2007

Consideration is given to the nature of the retrieval process with emphasis on the selection algorithm employed, and its relation to document set and query form.

Proof is given of the equivalence of Boolean and weighted search methods, this proof being based on the ability to convert any Boolean search request to weighted form and, similarly, any weighted request to Boolean form.
The stability of two common matching functions in classification with respect to a proposed measure
Authors: Yu C. T.
Published: June 2007

A measure for the quantification of the changes in classification under small changes in data is proposed. A comparison of two common matching functions, namely the single matching function and the cosine function, is made with respect to the measure. The sensitivities of clusters defined as connected components and as maximal complete subgraphs are also compared.
A general theory of bibliometric and other cumulative advantage processes
Authors: Price Derek De Solla
Published: June 2007

A Cumulative Advantage Distribution is proposed which models statistically the situation in which success breeds success. It differs from the Negative Binomial Distribution in that lack of success, being a non‐event, is not punished by increased chance of failure. It is shown that such a stochastic law is governed by the Beta Function, containing only one free parameter, and this is approximated by a skew or hyperbolic distribution of the type that is widespread in bibliometrics and diverse social science phenomena. In particular, this is shown to be an appropriate underlying probabilistic theory for the Bradford Law, the Lotka Law, the Pareto and Zipf Distributions, and for all the empirical results of citation frequency analysis. As side results one may derive also the obsolescence factor for literature use. The Beta Function is peculiarly elegant for these manifold purposes because it yields both the actual and the cumulative distributions in simple form, and contains a limiting case of an inverse square law to which many empirical distributions conform.
Development of a semantic differential to access users' attitudes towards a batch mode information retrieval system (ERIC)
Authors: Allen Sheilah , Matheson Joyce
Published: June 2007

A semantic differential scale was designed to assess users' attitudes toward a batch mode retrieval system based on the ERIC tape data base operated by the Information/Knowledge Research Center of the Faculty of Education of the University of British Columbia. Ten concepts representative of the system were grouped (Input, Output, and General) and matched with sixteen adjective pairs (Evaluative, Desirability, and Enormity). Demographic information was obtained from the 35 faculty members and graduate student users responding to the questionnaire. Although questionnaire returns were somewhat low (37%), statistical analysis by grouping and item analysis generally confirmed the hypothetical clustering of both concepts and adjective pairs. Moreover, credence was given to more recent semantic differential study results (Katzer, 1972) as opposed to the classic conclusions of Osgood, Suci, and Tannen‐baum (1957). A short form of the questionnaire was designed to provide for continuous evaluation of the system.
The effect of individual differences of cognitive style on judgments of document relevance
Authors: Davidson David
Published: June 2007

The possibility that the relevance decision may be affected by individual differences in openness to information is examined. Openness to information is operationally defined by a series of cognitive style variables (openmindedness, rigidity, category width, locus of control, anxiety, and defensiveness). A multiple‐regression technique was utilized to simultaneously test the effect of cognitive variables and previously tested variables tapping judges' interest and expertise in the problem area. Subjects made relevance decisions on a randomly generated list of citations for a question provided by the experimenter. Divergent behavior on the dependent variable (number of citations deemed relevant) by two groups of subjects necessitated splitting the initial sample of 48 into two independent groups of 25 and 23. The pattern of the empirical results conforms to the prediction that approximately 30% of the relevance‐decision variance is attributable to variables tapping openness to information. The empirical results do not reach the normative criterion of α = 0.05. It is argued that this finding is due to a decrease in power resulting from the decrease in sample size rather than from an inadequate or erroneous model. The results are discussed in terms of the relationship between information systems and the “epistemic who”.
Lotka's frequency distribution of scientific productivity
Authors: Coile Russell C.
Published: June 2007

In 1926, Alfred Lotka examined the frequency distribution of scientific productivity of chemists and physicists. After analyzing the number of publications of chemists listed in Chemical Abstracts 1907–1916 and the contributions of physicists listed in Auerbach's Geschi‐chtstafeln der Physik, he observed that the number of persons making n contributions is about 1/n2 of those making one and the proportion of all contributors that make a single contribution is about 60%. Recently, investigators studying the applicability of “Lotka's law” to the humanities and to map librarianship may have misinterpreted Lotka's law and have concluded erroneously that the law applies to these fields. Corrected calculations indicate that Lotka's law does not apply.
Frequency‐rank distributions
Authors: Brookes Bertram C. , Griffiths Jose M.
Published: June 2007

Frequency, rank, and frequency‐rank distributions are distinguished and discussion then focuses on frequency‐rank distributions. The key example of frequency‐rank distributions is the so‐called “law of anomalous numbers” which, modeled as a “very mixed” Poisson process and simulated by computer, provides a means of exploring the stability of ranks in sample frequency‐rank distributions. The paper concludes with a critical discussion of the correlation of frequency‐rank distributions and offers a new measure‐the transfer coefficient.
On the perils of merging boolean and weighted retrieval systems
Authors: Bookstein A.
Published: June 2007

Attempts have been made to rank the output of a Boolean search in terms of the overlap of index terms in the request and document. As attractive as the merger of two approaches may seem, a closer examination reveals disturbing ambiguities, with equivalent Boolean expressions yielding different weights for the retrieval documents. An alternative approach is suggested.
On the nature of fuzz: A diatribe
Authors: Robertson Stephen E.
Published: June 2007

The imprecision of some of the concepts which are used in formal models in information science has led to a spate of attempts to apply fuzzy set theory to aspects of information science. An analysis of the various kinds of imprecision that can occur indicates strongly that fuzzy set theory is not an appropriate formalism for these models.
Financial aspects of industrial information centers: A survey
Authors: Talavage Joseph
Published: June 2007

This article reports on a survey of the financial aspects of special libraries and information centers in American industrial companies. The objectives of this survey were to assess resources allocated to information centers, pricing behavior and cost behavior for such centers, and to obtain an indication of the accounting practices of such centers. Data on 41 characteristics were obtained from 87 centers in the Fortune 500 companies. The results of the data analysis are discussed and compared to other pertinent investigations of this type.
Nonbibliographic on‐line data base services
Authors: Wanger Judith , Landau Ruth N.
Published: June 2007

Over 400 data bases are available on‐line, and the majority of these are nonbibliographic. The nonbibliographic area encompasses a number of different types of data bases, including referral, numeric, textual‐numeric, chemical and physical properties, and full‐text. The growth in nonbibliographic data base services has been not nearly as visible to information specialists as the growth in bibliographic on‐line data base services. One reason for this is that the services are primarily being marketed to and used by end users, with libraries and information centers largely being bypassed. Some nonbibliographic data base systems are end‐user oriented, but there are many others that need to be studied for their possible applications in improving and extending traditional reference and other library and information services.
Compression of continuous prose texts using variety generation
Authors: Cooper David , Emly Michael A. , Lynch Michael F. , Yeates A. Robin
Published: June 2007

The use of variety‐generation techniques for text compression depends on the selection of symbol sets, or sets of variable‐length character strings occurring approximately equifrequently in the text in question. In order that the method perform efficiently in a variety of situations, the symbol set must be reasonably independent of the particular text used in its generation. Hence, texts of different origins must be similar in their microstructure for the technique to work well. Texts of American English varying in subject and style have been found to fulfill this condition. On average the texts can be represented with a space saving of just over 50% on the space used by a fixed‐length 8‐bit representation of the characters, and the best results are obtained using a symbol set generated from a sample of the complete data base, although results from subsets of the data base are almost as good.
Cocited author retrieval online: An experiment with the social indicators literature
Authors: White Howard D.
Published: June 2007

One mode of online retrieval in Scisearch or Social Scisearch involves entering pairs of authors' names believed to be jointly cited by subsequent writers and retrieving papers in which cocitations occur. Six pairs were formed with the names of four authors prominent in the social indicators movement (Bauer, Duncan, Land, and Sheldon). Documents by the four were not specified. It was thought that the pair Duncan and Land would retrieve papers in which indicator‐type data would be integrated with path‐analytic causal modeling. All other pairs seemed likely to retrieve a “general social indicators” literature. The 298 retrieved papers confirmed expectations. It was found that 121 papers generally cited social indicators (SI) documents by the input authors and frequently had SI language in their titles. Other signs of content also identified them as papers of the SI movement. The 177 papers retrieved on Duncan and Land generally cited causal modeling documents by the input pair and were path‐analytic in nature. As expected, they were relatively “harder” than the first group of papers, although the two groups are akin and are formally linked through citations in certain papers. An additional result is that papers citing at least three of the input authors tend to be overviews of the SI movement.
A model for a weighted retrieval system
Authors: Buell Duncan A. , Kraft Donald H.
Published: June 2007

There has been a good deal of work on information retrieval systems that have continuous weights assigned to the index terms that describe the records in the database, and/or to the query terms that describe the user queries. Recent articles have analyzed retrieval systems with continuous weights of either type and/or with a Boolean structure for the queries. They have also suggested criteria which such systems ought to satisfy and record evaluation mechanisms which partially satisfy these criteria. We offer a more careful analysis, based on a generalization of the discrete weights. We also look at the weights from an entirely different approach involving thresholds, and we generate an improved evaluation mechanism which seems to fulfill a larger subset of the desired criteria than previous mechanisms. This new mechanism allows the user to attach a “threshold” to the query term.
Improving library effectiveness: A proposal for applying fuzzy set concepts in the management of large collections
Authors: Robinson Earl J. , Turner Stephen J.
Published: June 2007

A new concept in mathematical modeling—fuzzy set theory—allows for the explicit consideration of “professional expertise and judgment.” This article introduces fuzzy set theory to the library community “at‐large” by providing (i) a brief historical perspective on fuzzy sets; (ii) an introduction to the fundamentals of fuzzy set theory; (iii) an avenue of approach for applications of the theory in a library environment; and (iv) suggestions for future development of fuzzy applications in the library management area.
Problems of information services with respect to integration of the sciences
Authors: Pachevsky Talmon
Published: June 2007

Current interdisciplinary information in science and technology was studied in connection with some aspects of the integration of the sciences. The investigation was carried out by combination of research methods such as testing, surveys, and source analysis. The experimental method for tracing relevant publications unknown to the user is described. The results of questionnaires sent to 432 specialists in 16 countries are presented. Some features of the integration of the sciences were investigated together with the specific information demands which they provoke. It is shown that these demands cannot be satisfied within the limits of discipline‐oriented information systems. Particular attention is given to information problems of small developed and developing countries. The efforts of these countries must concentrate on the compilation of information indexes on complex and interdisciplinary problems.
Bibliometric models for management of an information store. I. Differential utility among items
Authors: Parker Ralph H.
Published: June 2007

Differential demand for use among the items in an information store is a necessary condition for management of the store. Using bibliometric techniques for determination of the distribution of demand, the hypothesis of hyperbolic distribution, and an index of differential demand are developed.
The use of computer‐monitored data in information science and communication research
Authors: Rice Ronald E. , Borgman Christine L.
Published: June 2007

As computer‐based information retrieval and communication systems become more commonplace, researchers have a greater opportunity to evaluate the uses and impacts of new communication technologies. The systems and the kinds of data now available are discussed along with advantages and disadvantages of using computer‐monitored data.
Usage patterns of an online search system
Authors: Cooper Michael D.
Published: June 2007

This article examines the usage patterns of the ELHILL retrieval program of the National Library of Medicine's MEDLARS system. Based on a sample of 6759 searches, the study analyzes the frequency of various commands and command options, classifies messages issued by the system, and investigates searcher error rates. The article concludes with suggestions for improving and redesigning both the program and query language.
An experimental comparison of the effectiveness of computers and humans as search intermediaries
Authors: Marcus Richard S.
Published: June 2007

An experimental computer intermediary system, CONIT, that assists users in accessing and searching heterogeneous retrieval systems has been enhanced with various search aids. Controlled experiments have been conducted to compare the effectiveness of the enhanced CONIT intermediary with that of human expert interme diary search specialists. Some 16 end users, none of whom had previously operated either CONIT or any of the four connected retrieval systems, performed searches on 20 different topics using CONIT with no assistance other than that provided by CONIT itself (except to recover from computerlsoftware bugs). These same users also performed searches on the same topics with the help of human expert intermediaries who searched using the retrieval systems directly. Sometimes CONIT and sometimes the human expert were clearly superior in terms of such parameters as recall and search time. In general, however, users searching alone with CONIT achieved somewhat higher online recall at the expense of longer session times. We conclude that advanced experimental intermediary techniques are now capable of providing search assistance whose effectiveness at least approximates that of human intermediaries in some contexts. Also analyzed is the cost effectlveness of current intermediary systems. Finally, consideration is given to the prospects for much more advanced systems which would perform such functions as automatic database selection and the simulation of human experts, and thereby make information retrieval more effective for all classes of users.
Informational dynamics of journal article titles
Authors: Diener Richard A. V.
Published: June 2007

The informational dynamics of journal article titles was investigated by analyzing the changing informational value of titles over time. The Informational value of titles was measured by counting the total number of words (y τ) in a title, counting the number of substantive words (ys), or keywords, in a title, and computing the proportion of substantive words (yp = ys/yτ) In a title. Random samples of journal article titles were gathered from four selected journals, six library journals, and six miscellaneous journals over the period from 1951 through 1980. The informational values were averaged by year to yield annual means for Yτ, Ys, and Yp. The patterns of change of these annual means were analyzed over time by regression analysis. We questioned whether linear regression analysis would yield equations representing the underlying data with a 95% or greater level of confidence. The results of these analyses were linear equations of the form, y = mt + b, where y Is the dependent variable (informational value), m is the slope of the equation, t is the independent variable (time), and b is the y‐intercept of the equation. The sign (+ or ‐) of the slope (m) indicates the direction of change (increasing or decreasing) of the informational dynamics of journal article titles. A rate of change was computed by differential calculus by differentiating informational value with respect to time. Rate of change Indicates how rapidly change is occurring. The sample journals selected in this research represent the primary literature, the review literature, the physical science literature, the social science literature, the library literature, and a miscellaneous collection of six journals.
Morse's Markov model of book use revisited
Authors: Beheshti Jamshid , Tague Jean M.
Published: June 2007

Over a decade ago, P. M. Morse suggested a simple Markov model of book use for a science library. Since then, his model has been modified and used in a number of applications, but the reliability of the basic assumptions underlying the model's parameters has not been tested. Utilizing 11 years of circulation transactions of a university library, it is shown that (1) Morse's model fits approximately 99% of the data for the whole collection and for three subject areas, and (2) contrary to his assumptions, one of the model's two parameters, a, is time dependent.
Expert systems: A tutorial
Authors: Yaghmai N. Shahla , Maxin Jacqueline A.
Published: June 2007

Expert systems are intelligent computer applications that use data, a knowledge base, and a control mechanism to solve problems of sufficient difficulty that significant human expertise is necessary for their solution. Expert systems use artificial intelligence problem‐solving and knowledge‐representation techniques to combine human expert knowledge about a problem area with human expert methods of conceptualizing and reasoning about that problem area. As a result, it is expected that such systems can reach a level of performance comparable to that of a human expert in a specialized problem area. The high‐level knowledge base and associated control mechanism of expert systems are in essence a model of the expertise of the best practitioners of the problem area in question and, hence, human users are provided with expert opinions about problems in that area. Expert systems do not pretend to give final or ultimate conclusions to displace human decision making; they are intended for consulting purposes only.
A review and application of citation analysis methodology to reading research journal literature
Authors: Summers Edward G.
Published: June 2007

This article reviews citation analysis literature and explores the use of citation analysis as a method for identifying highly cited core journals and indicating the disciplinary structure and interrelations of journals reporting reading research. Citation data from the 1980 Journal Citation Reports were used to generate a journal size‐independent Reading Research Impact Factor as a criterion for selecting high impact journals. References from seven citing journals were used to produce a set of 92 candidate core list journals. After four iterations, a final diverse set of 27 highly cited journals emerged including publications from reading, education, educational psychology, educational research, language, cognitive psychology, general psychology, developmental and child psychology, and experimental psychology. Six journals from the area of communication were added to complete the list. Analysis of the 10‐year temporal distribution of recent citations from 25 of the highly cited journals pinpointed the immediacy effect of reading research as being on the borderline between hard and soft science with such research exhibiting a strong flavor from cognate areas of psychology. Problems and limitations related to citation analyses are discussed.