bluuebunny/crossref_metadata_2025 huggingface dataset:
J‐Edited Pure Shift NMR for the Facile Measurement of nJHH for Specific Protons
Authors: Chaudhari Sachin Rama , Suryaprakash N.
Published: January 2015

We report a novel 1D J‐edited pure shift NMR experiment (J‐PSHIFT) that was constructed from a pseudo 2D experiment for the direct measurement of proton–proton scalar couplings. The experiment gives homonuclear broad‐band 1H‐decoupled 1H NMR spectra, which provide a single peak for chemically distinct protons, and only retain the homonuclear‐scalar‐coupled doublet pattern at the chemical‐shift positions of the protons in the coupled network of a specific proton. This permits the direct and unambiguous measurement of the magnitudes of the couplings. The incorporation of a 1D selective correlation spectroscopy (COSY)/ total correlation spectroscopy (TOCSY) block in lieu of the initial selective pulse, results in the exclusive detection of the correlated spectrum of a specific proton.
Regioselective Long‐Range Proton Transfer in New Rifamycin Antibiotics: A Process in which Crown Ethers Act as Stronger Brønsted Bases than Amines
Authors: Pyta Krystian , Przybylski Piotr , Bartl Franz
Published: January 2015

Water‐mediated proton transfer in six new derivatives of 3‐formylrifamycin SV that contain crown, aza‐crown, and benzo‐crown ether rings were investigated by FTIR and NMR spectroscopy. 1H–1H COSY couplings provide evidence for the formation of zwitterionic structures of the aza‐crown and crown ether derivatives of rifamycin, in which a proton from one of the phenolic groups is transferred to tertiary and secondary nitrogen atoms. The increased intensity of the continuous absorption in the mid‐infrared region together with the NMR data indicate proton transfer from the phenol group of the rifamycin core to the cavity of the benzo‐crown ether ring. This proton transfer is achieved by formation of hydronium (H3O+) or Zundel ions (H5O2+), which form intermolecular hydrogen bonds with the oxygen atoms of the crown ether. DFT calculations are in agreement with the spectroscopic data and allow visualization of the structures of all new rifamycin derivatives, characterized by different intramolecular protonation sites.
From Lignocellulosic Biomass to Lactic‐ and Glycolic‐Acid Oligomers: A Gram‐Scale Microwave‐Assisted Protocol
Authors: Carnaroglio Diego , Tabasso Silvia , Kwasek Beata , Bogdal Dariusz , Gaudino Emanuela Calcio , Cravotto Giancarlo
Published: January 2015

The conversion of lignocellulosic biomass into platform chemicals is the key step in the valorization of agricultural waste. Of the biomass‐derived platform chemicals currently produced, lactic acid plays a particularly pivotal role in modern biorefineries as it is a versatile commodity chemical and building block for the synthesis of biodegradable polymers. Microwave‐assisted processes that furnish lactic acid avoid harsh depolymerization conditions while cutting down reaction time and energy consumption. We herein report a flash catalytic conversion (2 min) of lignocellulosic biomass into lactic and glycolic acids under microwave irradiation. The batch procedure was successfully adapted to a microwave‐assisted flow process (35 mL min−1), with the aim of designing a scalable process with higher productivity. The C2 and C4 units recovered from the depolymerization were directly used as the starting material for a solvent and catalyst‐free microwave‐assisted polycondensation that afforded oligomers in good yields.
Cellular immune surveillance of central nervous system bypasses blood–brain barrier and blood–cerebrospinal–fluid barrier: Revealed with the New Marburg cerebrospinal–fluid model in healthy humans
Authors: Kleine Tilmann O.
Published: January 2015

In healthy human brain/spinal cord, blood capillaries and venules are locked differently with junctions and basement membrane (blood–brain barrier, blood–venule barrier). In choroid plexus, epithelial tight junctions and basement membrane lock blood‐cerebrospinal‐fluid (CSF) barrier. Lymphocytic cell data, quantified with multicolour flow‐cytometry or immuno‐cytochemical methods in sample pairs of lumbar CSF, ventrictricular CSF and peripheral venous blood, are taken from references; similarly, data of thoracic duct chyle and blood sample pairs. Through three circumventricular organs (median eminence, organum vasculosum lamina terminalis, area postrema), 15–30 μl blood are pressed by blood pressure through fenestrated capillaries, matrix/basement membrane spaces and ependyma cell lacks into ventricular/suboccipital CSF to generate CD3+, CD4+, CD8+, CD3+HLA‐DR+, CD16+56+3– NK, CD19+3– B subsets; some B, few NK cells adhere in circumventricular organs. Into lumbar CSF, 10–15 μl thoracic chyle with five lymphocyte subsets (without CD3+HLA‐DR+ cells) reflux, when CSF drains out with to‐and‐fro movements of chyle/CSF along nerve roots. Lymphocytes in lumbar CSF represent a mixture of blood and lymph lymphocytic cells with similar HLA‐DR+CD3+ cell counts in ventricular and lumbar CSF, higher CD3+, CD4+, CD8+ subsets in lumbar CSF, and few NK and B cells due to absorption in circumventricular organs. The Marburg CSF Model reflects origin and turnover of lymphatic cells in CSF realistically; the model differs from ligand‐multistep processes of activated lymphocytes through blood–brain‐, blood–venule‐, and blood–CSF‐barriers; because transfer of inactivated native lymphocytes through the barriers is not found with healthy humans, although described so in literature. © 2015 International Society for Advancement of Cytometry
Image‐based systems biology of infection
Authors: Medyukhina Anna , Timme Sandra , Mokhtari Zeinab , Figge Marc Thilo
Published: January 2015

The successful treatment of infectious diseases requires interdisciplinary studies of all aspects of infection processes. The overarching combination of experimental research and theoretical analysis in a systems biology approach can unravel mechanisms of complex interactions between pathogens and the human immune system. Taking into account spatial information is especially important in the context of infection, since the migratory behavior and spatial interactions of cells are often decisive for the outcome of the immune response. Spatial information is provided by image and video data that are acquired in microscopy experiments and that are at the heart of an image‐based systems biology approach. This review demonstrates how image‐based systems biology improves our understanding of infection processes. We discuss the three main steps of this approach—imaging, quantitative characterization, and modeling—and consider the application of these steps in the context of studying infection processes. After summarizing the most relevant microscopy and image analysis approaches, we discuss ways to quantify infection processes, and address a number of modeling techniques that exploit image‐derived data to simulate host‐pathogen interactions in silico. © 2015 International Society for Advancement of Cytometry
Repetitive motor behavior: Further characterization of development and temporal dynamics
Authors: Muehlmann Amber M. , Bliznyuk Nikolay , Duerr Isaac , Lewis Mark H.
Published: January 2015

Repetitive behaviors are diagnostic for autism spectrum disorders, common in related neurodevelopmental disorders, and normative in typical development. In order to identify factors that mediate repetitive behavior development, it is necessary to characterize the expression of these behaviors from an early age. Extending previous findings, we characterized further the ontogeny of stereotyped motor behavior both in terms of frequency and temporal organization in deer mice. A three group trajectory model provided a good fit to the frequencies of stereotyped behavior across eight developmental time points. Group based trajectory analysis using a measure of temporal organization of stereotyped behavior also resulted in a three group solution. Additionally, as the frequency of stereotyped behavior increased with age, the temporal distribution of stereotyped responses became increasingly regular or organized indicating a strong association between these measures. Classification tree and principal components analysis showed that accurate classification of trajectory group could be done with fewer observations. This ability to identify trajectory group membership earlier in development allows for examination of a wide range of variables, both experiential and biological, to determine their impact on altering the expected trajectory of repetitive behavior across development. Such studies would have important implications for treatment efforts in neurodevelopmental disorders such as autism. © 2015Wiley Periodicals, Inc. Dev Psychobiol 57: 201–211, 2015.
Human CD8 T lymphocytes recognize Mycobacterium tuberculosis antigens presented by HLA‐E during active tuberculosis and express type 2 cytokines
Authors: Caccamo Nadia , Pietra Gabriella , Sullivan Lucy C. , Brooks Andrew G. , Prezzemolo Teresa , La Manna Marco P. , Di Liberto Diana , Joosten Simone A. , van Meijgaarden Krista E. , Di Carlo Paola , Titone Lucina , Moretta Lorenzo , Mingari Maria C. , Ottenhoff Tom H. M. , Dieli Francesco
Published: January 2015

CD8 T cells contribute to protective immunity against Mycobacterium tuberculosis. In humans, M. tuberculosis reactive CD8 T cells typically recognize peptides associated to classical MHC class Ia molecules, but little information is available on CD8 T cells recognizing M. tuberculosis Ags presented by nonclassical MHC class Ib molecules. We show here that CD8 T cells from tuberculosis (TB) patients recognize HLA‐E‐binding M. tuberculosis peptides in a CD3/TCR αβ mediated and CD8‐dependent manner, and represent an additional type of effector cells playing a role in immune response to M. tuberculosis during active infection. HLA‐E‐restricted recognition of M. tuberculosis peptides is detectable by a significant enhanced ex vivo frequency of tetramer‐specific circulating CD8 T cells during active TB. These CD8 T cells produce type 2 cytokines upon antigenic in vitro stimulation, help B cells for Ab production, and mediate limited TRAIL‐dependent cytolytic and microbicidal activity toward M. tuberculosis infected target cells. Our results, together with the finding that HLA‐E/M. tuberculosis peptide specific CD8 T cells are detected in TB patients with or without HIV coinfection, suggest that this is a new human T‐cell population that participates in immune response in TB.
Phosphoinositide‐dependent protein kinase 1 (PDK1) mediates potent inhibitory effects on eosinophils
Authors: Sturm Eva M. , Parzmair Gerald P. , Radnai Balázs , Frei Robert B. , Sturm Gunter J. , Hammer Astrid , Schuligoi Rufina , Lippe Irmgard Th. , Heinemann Akos
Published: January 2015

Prostaglandin E2 (PGE2) protects against allergic responses via binding to prostanoid receptor EP4, which inhibits eosinophil migration in a PI3K/PKC‐dependent fashion. The phosphoinositide‐dependent protein kinase 1 (PDK1) is known to act as a downstream effector in PI3K signaling and has been implicated in the regulation of neutrophil migration. Thus, here we elucidate whether PDK1 mediates inhibitory effects of E‐type prostanoid receptor 4 (EP4) receptors on eosinophil function. Therefore, eosinophils were isolated from human peripheral blood or differentiated from mouse BM. PDK1 signaling was investigated in shape change, chemotaxis, CD11b, respiratory burst, and Ca2+ mobilization assays. The specific PDK1 inhibitors BX‐912 and GSK2334470 prevented the inhibition by prostaglandin E2 and the EP4 agonist ONO‐AE1‐329. Depending on the cellular function, PDK1 seemed to act through PI3K‐dependent or PI3K‐independent mechanisms. Stimulation of EP4 receptors caused PDK1 phosphorylation at Ser396 and induced PI3K‐dependent nuclear translocation of PDK1. EP4‐induced inhibition of shape change and chemotaxis was effectively reversed by the Akt inhibitor triciribine. In support of this finding, ONO‐AE1‐329 induced a PI3K/PDK1‐dependent increase in Akt phosphorylation. In conclusion, our data illustrate a critical role for PDK1 in transducing inhibitory signals on eosinophil effector function. Thus, our results suggest that PDK1 might serve as a novel therapeutic target in diseases involving eosinophilic inflammation.
A Macrocyclic 2,2′‐Bibenzimidazole Ruthenium(II) Chromophore as a Versatile Building Block for Supramolecular Devices
Authors: Sorsche Dieter , Rau Sven
Published: January 2015

We present the synthesis of a macrocyclic ruthenium(II) complex that combines the versatile photophysics and supramolecular chemistry of biimidazole ruthenium(II) chromophores with a macrocyclic geometry that allows for its introduction into mechanically interlocked frameworks. Structural information on the core framework was gained from a solid‐state structure. The new supramolecular building block shows that the principal photophysics of the ruthenium chromophore, that is, the cation‐driven light‐switch effect, are retained during the formation of the macrocycle.
Allylpalladium(II) Histidylidene Complexes and Their Application in Z‐Selective Transfer Semihydrogenation of Alkynes
Authors: Drost Ruben M. , Broere Daniël L. J. , Hoogenboom Jorin , de Baan Simone N. , Lutz Martin , de Bruin B. , Elsevier C. J.
Published: January 2015

We have studied the use of amino acid histidine as a precursor for N‐heterocyclic carbene (NHC) ligands. This natural amino acid possesses an imidazole substituent, which makes it an interesting NHC precursor that contains both an acid and an amino functionality. These functionalities may be used for further tuning of NHC complexes. We have developed routes for the synthesis of symmetric and dissymmetric alkyl, benzyl, and aryl‐substituted histidinium salts. Subsequently, the corresponding Ag and Pd histidylidenes were synthesized and the palladium complexes were tested in the Z‐selective transfer semihydrogenation of alkynes. Histidylidene palladium complexes that contain additional donor functionalities were found to display good selectivities. The best catalytic results were obtained with a Pd‐histidylidene complex that contains two picolyl functional groups.
The Diels–Alder Approach to Δ9‐Tetrahydrocannabinol Derivatives
Authors: Gläser Franziska , Bröhmer Manuel C. , Hurrle Thomas , Nieger Martin , Bräse Stefan
Published: January 2015

We have developed an efficient strategy for the synthesis of tetrahydrocannabinol derivatives based on an unsubstituted aromatic compound. A Diels–Alder reaction of vinylchromene with an electron‐poor dienophile gave a tricycle. We describe several methods for the functionalization of this compound, e.g., alkylation, reduction, and lactonization. We also studied the hydrogenation of some of these functionalized cannabinoid compounds to give cannabinoid‐like skeletons. Of these reactions, a tetracycle containing a lactone gave the best result, with a quantitative yield using PtO2 (5 mol‐%) and an atmospheric pressure of hydrogen. These numerous reactions can be applied to substituted aromatic starting materials to obtain a facile and modular route to Δ9‐tetrahydrocannabinol, or alternatively, with different substituents, to other cannabinoid analogues.
One‐Pot Directed Alkylation/Deprotection Strategy for the Synthesis of Substituted Pyrrole[3,4‐d]pyridazinones
Authors: Nair Reji N. , Bannister Thomas D.
Published: January 2015

In the course of a structure–activity relationship study of pyrrole[3,4‐d]pyridazinones, we optimized conditions for a one‐pot directed lithiation/alkylation reaction that also promoted in situ cleavage of a tert‐butoxycarbonyl (Boc) protecting group on the pyrrole ring. The efficiency of the process gave access to a number of substituted analogs of interest as possible antitumor agents.
Synthesis of Antitumor Carbazole‐Amonafide Structural Hybrids
Authors: Rozovsky Alex , Regozin Elena , Oron‐Herman Mor , Albeck Amnon , Gellerman Gary
Published: January 2015

A facile synthesis of new antitumor [4,5‐bc]carbazole‐amonafide derivatives is described. These compounds represent a new class of structural hybrids that contain the medicinally important carbazole and amonafide cores. The synthesis involves a Suzuki–Miyaura coupling of bromoamonafide with arylboronic acid reagents followed by the introduction of an azide group and subsequent regiospecific thermal nitrene insertion to yield carbazole‐amonafide hybrids in good yields. Preliminary antiproliferative assays against cancer and benign cell lines identified compounds with selective antitumor activity that exhibited submicromolar IC50 values.
Cytochrome c‐Derived Hybrid Systems Based on Moleculary Imprinted Polymers
Authors: Yarman Aysu , Dechtrirat Decha , Bosserdt Maria , Jetzschmann Katharina J. , Gajovic‐Eichelmann Nenad , Scheller Frieder W.
Published: January 2015

Hybrid architectures which combine a MIP with an immobilized “affinity ligand” or a biocatalyst sum up the advantages of both components. In this paper, hybrid architectures combining a layer of a molecularly imprinted electropolymer with a mini‐enzyme or a self‐assembled monolayer will be presented. (i) Microperoxidase‐11 (MP‐11) catalyzed oxidation of the drug aminopyrine on a product‐imprinted sublayer: The peroxide dependent conversion of the analyte aminopyrine takes place in the MP‐11 containing layer on top of a product‐imprinted electropolymer on the indicator electrode. The hierarchical architecture resulted in the elimination of interfering signals for ascorbic acid and uric acid. An advantage of the new hierarchical structure is the separation of MIP formation by electropolymerization and immobilization of the catalyst. In this way it was for the first time possible to integrate an enzyme with a MIP layer in a sensor configuration. This combination has the potential to be transferred to other enzymes, e.g. P450, opening the way to clinically important analytes. (ii) Epitope‐imprinted poly‐scopoletin layer for binding of the C‐terminal peptide and cytochrome c (Cyt c): The MIP binds both the target peptide and the parent protein almost eight times stronger than the non‐imprinted polymer with affinities in the lower micromolar range. Exchange of only one amino acid in the peptide decreases the binding by a factor of five. (iii) MUA‐poly‐scopoletin MIP for cytochrome c: Cyt c bound to the MIP covered gold electrode exhibits direct electron transfer with a redox potential and rate constant typical for the native protein. The MIP cover layer suppresses the displacement of the target protein by BSA or myoglobin. The combination of protein imprinted polymers with an efficient electron transfer is a new concept for characterizing electroactive proteins such as Cyt c. The competition with other proteins shows that the MIP binds its target Cyt c preferentially and that molecular shape and the charge of protein determine the binding of interfering proteins.
Enzymatic Delignification of Biomass for Enhanced Fermentable Sugars Production
Authors: Al‐Zuhair Sulaiman , Abualreesh Mohammed , Ahmed Khalda , Abdul Razak Ashir
Published: January 2015

The United Arab Emirates (UAE) has more than 40 million palm trees producing approximately 15 kg of waste fronds per tree. These fronds contain a large portion of polysaccharides, which can be hydrolyzed to simple fermentable sugars. Seaweed consists of macroalgae containing high portions of polysaccharides, which are also abundantly found on the coasts of UAE. The effectiveness of lignin to degrade enzymes for the pretreatment of biomass from palm trees fronds and indigenous seaweed (prior to enzymatic hydrolysis) has been investigated and compared to conventional chemical treatment. By treating with laccase, up to 9 and 24 % additional lignin was removed from palm fronds and seaweed, respectively. The performance of laccase was enhanced by using an ionic liquid, and a sugar yield of 12.6 % was achieved after treatment with laccase for only 1 hour. The proposed approach provides a promising simplification to the overall bioethanol production from biomass waste available globally in abundance, and in the UAE in particular.
Kinematic internal forces in deep foundations with inclined piles
Authors: Padrón Luis A. , Suárez Adrián , Aznárez Juan J. , Maeso Orlando
Published: January 2015

This paper presents a parametric study that looks into the influence of pile rake angle on the kinematic internal forces of deep foundations with inclined piles. Envelopes of maximum kinematic bending moments, shear forces and axial loads are presented along single inclined piles and 2 × 2 symmetrical square pile groups with inclined elements subjected to an earthquake generated by vertically incident shear waves. Inclination angles from 0° to 30° are considered, and three different pile–soil stiffness ratios are studied. These results are obtained through a frequency–domain analysis using a boundary element–finite element code in which the soil is modelled by the boundary element method as a homogeneous, viscoelastic, unbounded region, and the piles are modelled by finite elements as Euler–Bernoulli beams. The rotational kinematic response of the pile foundations is shown to be a key factor on the evolution of the kinematic internal forces along the foundations. Copyright © 2015 John Wiley & Sons, Ltd.
Complexity and non‐linearity in earth surface processes – concepts, methods and applications
Authors: Temme Arnaud J.A.M. , Keiler Margreth , Karssenberg Derek , Lang Andreas
Published: January 2015

Complexity has long been recognized and is increasingly becoming mainstream in geomorphology. However, the relative novelty of various concepts and techniques associated to it means that ambiguity continues to surround complexity. In this commentary, we present and discuss a variety of recent contributions that have the potential to help clarify issues and advance the use of complexity in geomorphology. Copyright © 2015 John Wiley & Sons, Ltd.
Application of a thermodynamically compatible two‐phase flow model to the high‐resolution simulations of compressible gas–magma flow
Authors: Zeidan D. , Touma R. , Slaouti A.
Published: January 2015

This paper reports on the application and development of a fully hyperbolic and fully conservative two‐phase flow model for the simulation of gas and magma flow within volcanic processes. The model solves a set of mixture conservation equations for the gas and magma two‐phase flow with velocity non‐equilibrium. In this model, the effect of the relative velocity is introduced by a kinetic constitutive equation with other equations for volume and mass fractions of the gas phase. The model is examined numerically by the widely used finite volume Godunov methods of centered‐type. Using the Riemann problem, we numerically simulate wave propagation and the development of shocks and rarefactions in volcanic eruptions. These simulations are of magma fragmentation type where the relative velocity continues to dominate. A series of test cases whose solution contains features relevant to gas–magma mixtures are conducted. In particular, numerical results indicate that the model implementation predicts key features of the relative velocity within volcanic processes without any mathematical or physical simplifications. Simulation results are sharply and accurately provided without any spurious oscillations in all of the flow variables. The numerical methods and results are also compared with other numerical methods available in the literature. It is found that the provided resolutions are more accurate for the considered test cases. Copyright © 2014 John Wiley & Sons, Ltd.
Fossil care and fossil studies: Andy Currant, former curator of the fossil mammals collections at the Natural History Museum, London
Authors: Stringer Chris , Delbarre Gabrielle , Hooker Jerry , Kruszynski Robert
Published: January 2015

For over 40 years Andy Currant curated the Fossil Mammal Collections at the Natural History Museum, London, during which time he provided gentle fossil care to over 100 000 internationally important specimens collected from around the world. Specializing in the study of Pleistocene mammal bones, he rapidly became a leading research scientist in the British Quaternary faunal record. His research and fieldwork, on numerous excavations in the UK and abroad, led him to create a biostratigraphic model framework for the Quaternary mammal fauna which contributed to further knowledge about climatic changes during the later Pleistocene. As a curator, his own excavations into the Museum's collections resulted in the discovery or rediscovery of iconic historically important specimens. Copyright © 2015 John Wiley & Sons, Ltd.
The deer from the early Middle Pleistocene site of Isernia la Pineta (Molise, Italy): revised identifications and new remains from the last 15 years of excavation
Authors: Breda M. , Peretto C. , Thun Hohenstein U.
Published: January 2015

The deer remains from the renowned Palaeolithic site of Isernia la Pineta (southern Italy) are revised. Both material already published, and new specimens from the last 15 years of excavation, is taken into account and some identifications are revised. The published assemblage consists of Megaceroides solilhacus, Cervus sp. cf. C. elaphus acoronatus, Dama sp. cf. D. clactoniana and Capreolus sp. The literature dealing with these species is discussed and the problems still unresolved are outlined. The giant deer, now assigned by most authors to the genus Praemegaceros as P. solilhacus, is the largest and most common deer species at the site, represented by numerous antler fragments plus a few isolated teeth and fragmentary postcranial elements. The retrieval of new, well‐preserved specimens, namely one nearly complete antler, plus a distal portion of palmation, two neural skulls and one premaxillary bone, allows a better characterization of this otherwise still poorly understood species. The sub‐specific attribution of the red deer, in the lack of more complete antler specimens, is still dubious. The fallow deer remains probably belong to Dama roberti, a recently described species from the early Middle Pleistocene of Western Europe. The morphology of the lower portion of the only preserved antler fits better with this species rather than with D. clactoniana, to which it was previously tentatively assigned. At last, the specific identity of the few roe deer remains from Isernia is discussed, but the problem remains unanswered because of lack of agreement, in the literature, about the taxonomy of the Pleistocene species. Copyright © 2015 John Wiley & Sons, Ltd.
The effect of forcing and landscape distribution on performance and consistency of model structures
Authors: Euser Tanja , Hrachowitz Markus , Winsemius Hessel C. , Savenije Hubert H.G.
Published: January 2015

It is often challenging to determine the appropriate level of spatial model forcing and model distribution in conceptual rainfall‐runoff modelling. This paper compares the value of incorporating both spatially distributed forcing data and spatially distributed model conceptualisations based on landscape heterogeneity, applied to the Ourthe catchment in Belgium. Distributed forcing data were used to create a spatial distribution of model states. Eight different configurations were tested: a lumped and distributed model structure, each with four levels of model state distribution. The results show that in the study catchment the distributed model structure can in general better reproduce the dynamics of the hydrograph, and furthermore, that the differences in performance and consistency between calibration and validation are smallest for the distributed model structure with distributed model states. For the Ourthe catchment, it can be concluded that the positive effect of incorporating a distributed model structure is larger than that of incorporating distributed model states. Distribution of model structure increases both model performance and consistency. Copyright © 2015 John Wiley & Sons, Ltd.
ESTIMATION OF LATENT ABILITY USING A RESPONSE PATTERN OF GRADED SCORES1
Authors: Samejima Fumi
Published: January 2015

Estimation of latent ability using the entire response pattern of free‐response items is discussed, first in the general case and then in the case where the items are scored in a graded way, especially when the thinking process required for solving each item is assumed to be homogeneous.

The maximum likelihood estimator, the Bayes modal estimator, and the Bayes estimator obtained by using the mean‐square error multiplied by the density function of the latent variate as the loss function are taken as our estimators. Sufficient conditions for the existence of a unique maximum likelihood estimator and a unique Bayes modal estimator are formulated with respect to an individual item rather than with respect to a whole set of items, which are useful especially in the situation where we are free to choose optimal items for a particular examinee out of the item library in which a sufficient number of items are stored with reliable quality controls.

Advantages of the present methods are investigated by comparing them with those which make use of conventional dichotomous items or test scores, theoretically as well as empirically, in terms of the amounts of information, the standard errors of estimators, and the mean‐square errors of estimators. The utility of the Bayes modal estimator as a computational compromise for the Bayes estimator is also discussed and observed. The relationship between the formula for the item characteristic function and the philosophy of scoring is observed with respect to dichotomous items.
VARIABILITY OF KUDER‐RICHARDSON FORMULA 20 RELIABILITY ESTIMATES
Authors: Cleary T. Anne , Linn Robert L.
Published: January 2015

The standard error of a Kuder‐Richardson Formula 20 reliability coefficient is derived and two approximations to it are presented. The values from the exact solutions and from the approximations are compared with empirical values.
ESTIMATING ITEM CHARACTERISTIC CURVES WITHOUT KNOWLEDGE OF THEIR MATHEMATICAL FORM*
Authors: Lord Frederic M.
Published: January 2015

A method is outlined for estimating item characteristic curves without knowledge of their mathematical form. For illustrative purposes, the method is applied to five items from a regular test administration. Previously, curves had been estimated for these same items on the assumption that all were of logistic form. Surprising agreement was found between the results obtained from the two unrelated methods.
THE FACTOR ANALYSIS OF AFRICAN ABILITIES AND ATTAINMENTS: CONSTRUCTS ACROSS CULTURES1
Authors: Irvine S. H.
Published: January 2015

This paper is based on the results of experimental investigations in east and central Africa, involving field studies of over 5,000 subjects. It illustrates the application of Factorial Analysis in the search for the psychological and descriptive meaning of test scores derived from African subjects taking tests adapted from those currently in use in western societies or standardized on African subjects. Results suggest that although tests tend consistently to group themselves together in ways explicable in terms of Western constructs such as ‘g‘, v:ed and n:ed, sources of variance exist unique to the environment of the society in which the tests are administered Of particular note are the identification of an educational aptitude factor associated with males, and the less stable nature of perceptual and spatial factors. Discussion centres on the contribution of the study towards a cross‐cultural interpretation of educational abilities in terms of a limited transfer of a value system in which the concept of intelligence is a key term.
FACTOR STABILITY OF A STUDENT BIOGRAPHICAL INFORMATION BLANK OVER SEVERAL GRADE LEVELS
Authors: Freeberg Norman E. , Rock Donald A.
Published: January 2015

A biographical information blank (BIB), administered to students in grades 7, 9, and 11 in 1963 as part of the ETS Growth Study, was analyzed to determine the stability of its factor structure. This was done by deriving a single average factor pattern matrix which was rotated to simple structure and against which factor matrices at each grade level could be compared. Of 11 factors extracted, all but three showed reasonably good stability. Those factors that showed the greatest change, in terms of their presence over the three grade levels, were “General Appreciation of School Courses,” “Social Activities,” and “High Level Literary Activities.”

Implications of stability in factor structure for further BIB development and for utilization in the framework of a longitudinal study are discussed.
A GENERAL APPROACH TO PROCRUSTES PATTERN ROTATION1
Authors: Gruvaeus Gunnar T.
Published: January 2015

A method is introduced for oblique rotation to a pattern target matrix specified in advance. The target matrix may have all or only some of its elements specified. The computational procedure consists of a series of numerical minimizations. Results are shown using data from Harman and Browne.
TEST DIMENSIONS, TEST ANXIETY, AND TEST PERFORMANCE1
Authors: Bloxom Bruce
Published: January 2015

A multidimensional scaling of test situations indicates that tests can differ in their tension‐ (or anxiety‐) arousing properties, at least as a function of (a) the subjective importance of the test and (b) how well prepared the person feels for the test. Different points of view about the influence of these two variables are assessed. Relationships among the points of view, test anxiety, test performance, defensiveness, and acquiescence are examined.
EFFECTS OF ANTICIPATED DELEGATE STATUS ON LEVEL OF RISK TAKING IN SMALL DECISION‐MAKING GROUPS1
Authors: Kogan Nathan , Doise Willem
Published: January 2015

The oft‐replicated risky‐shift phenomenon in decision‐making groups was examined under conditions where one or all of the group members expected to serve as a delegate representing and defending their group's decisions in meetings with delegates from other groups. Three separate delegate conditions and a control were employed. In two of the conditions a single delegate was selected–designated by the group in one case and chosen at random in the other. In a third condition, all members expected to serve as delegates. The control condition consisted of the standard group discussion‐to‐consensus without any delegate manipulation. No mean differences in magnitude of risky shift between conditions were obtained. An examination of the two single‐delegate conditions revealed other kinds of differences. Whereas the behavior of the delegate selected randomly appeared to have little effect on the size of the risky shift, this was not the case for the group‐designated delegate. Correlational analyses indicated that the latter's influence and communication input and output were related to risky‐shift magnitude.
SOME ORIGINS OF CONCERN FOR OTHERS1
Authors: Rosenhan David
Published: January 2015

This paper summarizes a series of naturalistic and experimental investigations into the nature of personal commitment and prosocial behavior.

An intensive naturalistic study of Civil Rights workers distinguished those who were fully committed (i.e., had actively participated in Civil Rights activities for more than a year) from those who were partially committed (i.e., had gone on one or two Freedom Rides) on the basis of the kinds of models to which they were exposed as children. The parent of the fully committed was a behavioral altruist, fully committed to a social cause. Moreover, he maintained a strong positive relationship with the child. The parent of the partially committed, on the other hand, was described as having often failed to practice what he preached, and maintained a negative or ambivalent relationship with the child.

These observations were examined in a variety of experiments that were predicated on social learning theory. In one, adolescents who observed a model rebel against authority for prosocial reasons tended themselves subsequently to rebel more than their peers who had observed an obedient model. In another, children who observed a model contribute to charity tended also to contribute, even in the absence of adult surveillance. However, these findings, while statistically significant, were nevertheless quite weak. Additional experiments provided strong evidence that while observation of a model was helpful, internalization of prosocial norms was more strongly facilitated by the opportunity to rehearse prosocial behavior voluntarily with the model.

In a series of developmental studies it was found that internalization of prosocial norms occurred rarely with five‐year‐old children, but quite commonly with eight‐ and nine‐year‐old ones. This finding was puzzling since the required behaviors were neither physically nor psychologically taxing. It was proposed that the internalization of prosocial behavior on the basis of observation of others may require a predisposing cognitive and affective matrix, the elements of which are briefly elaborated.
SCALING A SIMPLEX SYMMETRICALLY
Authors: Schönemann Peter
Published: January 2015

A method for scaling a perfect simplex [Guttman, 1954] is suggested which, in contrast to Kaiser's [1962], is independent of the order of the manifest variables. It is based on a procedure for scaling a set of points from their pairwise distances [Torgerson, 1958; Young & Householder, 1938] which is reviewed in compact notation. The scaling method is extended to an iterative algorithm for scaling a quasi‐simplex. Some empirical results are included.
INDIRECT METHODS OF ASSESSING PERSONALITY1
Authors: Hermann Margaret G.
Published: January 2015

This review suggests alternatives to testing in personality assessment. The methods which are described focus on nonverbal and verbal indices of transient and stable personality characteristics. The verbal indices cover the structure and content of what is spoken or written; the nonverbal indices include gross body movements, gestures, tone of voice, and style of writing. In addition to providing options to tests, these indirect measures make the study of hard‐to‐approach groups and the use of field settings more feasible.
A PRINCIPAL COMPONENTS ANALYSIS OF MODELS AND MEN
Authors: Wainer Howard
Published: January 2015

One consequence of stimulus sampling theory is the prediction of probability matching as the asymptotic response probability. That is, subjects tend to choose each alternative with the frequency of its reinforcement. This prediction has been tested in many experiments and the boundaries within which it holds have been delineated. However, the experiments which find probability matching have been criticized for doing one or more of several inappropriate things.

It should be noted that probability matching is not a “rational” solution, in the sense that the behavior which maximizes gain would be always to choose the more frequently reinforced response. Some investigators have found it possible to devise experimental situations in which the subjects do come closer to maximizing behavior.

This study attempts to differentiate the conditions which lead to “matching” behavior from those which lead to “maximizing” and to develop a mathematical model for this behavior.

The experimental results indicate that the prediction of probability matching does not obtain. Therefore, it would seem to be probable that the stimulus sampling theory which predicts this behavior also does not apply. One of the axioms of stimulus sampling theory has been generalized. An effect of this revision is to allow for the prediction of nonprobability matching behavior. This model has been fitted to the data previously gathered, and described the data far better than any previous stimulus sampling model.

It is concluded that probability matching is not a general learning law as Estes proposed in 1957, but, rather, that it is a special case of a more general phenomenon, just as previous stimulus sampling models are special cases of the model developed here.

The major analytic tool in this study was a principal components analysis of the learning data. The inter‐factor plot of factor scores was used to compare the relative fit of the various forms of stimulus sampling models studied.
Stem cell recruitment, angiogenesis, and tissue regeneration in substance P‐conjugated poly(l‐lactide‐co‐ɛ‐caprolactone) nonwoven meshes
Authors: Shafiq Muhammad , Jung Youngmee , Kim Soo Hyun
Published: January 2015

Recruitment of endogenous stem cells to impaired tissues holds enormous potential to regenerative medicine. In this study, we examined whether covalently conjugated substance P (SP) would significantly enhance the recruitment of stem cells and promote angiogenesis in poly(l‐lactide‐co‐ε‐caprolactone) (P(LA‐co‐CL)) meshes. SP was conjugated with star‐shaped P(LA‐co‐CL) copolymer using carbonyldiimidazole chemistry. P(LA‐co‐CL) and SP‐conjugated star‐shaped P(LA‐co‐CL) copolymers were mixed in appropriate proportions and electrospun to fabricate nonwoven meshes. Amino acid analysis confirmed the conjugation of SP with star‐shaped P(LA‐co‐CL) copolymers. Conjugated SP remained bioactive and recruited human bone‐marrow‐derived mesenchymal stem cells in an in vitro transwell migration assay. Moreover, SP was released in a sustained fashion from the nonwoven meshes for up to 30 days. P(LA‐co‐CL) as well as SP containing meshes were implanted subcutaneously in Sprague‐Dawley rats (n = 16) for 14 and 21 days. Hematoxylin and eosin staining of the retrieved samples revealed cellularization of P(LA‐co‐CL) as well as SP containing meshes. Large and mature blood vessels were observed in greater numbers in SP‐containing meshes compared with their control counterparts as revealed by Masson's trichrome staining. We also observed a larger number of von Willebrand factor‐positive vessels in SP‐containing meshes than in the controls. Significantly large numbers of CD29‐ and CD90‐positive stem cells were recruited in the meshes containing SP. Collectively, these findings suggest that the methodology presented may have broad applications in regenerative medicine, and these novel scaffolding materials can be used for in situ tissue regeneration of soft tissues. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 2673–2688, 2015.
The role of nanostructures and hydrophilicity in osseointegration: In‐vitro protein‐adsorption and blood‐interaction studies
Authors: Kopf Brigitte S. , Ruch Sylvie , Berner Simon , Spencer Nicholas D. , Maniura‐Weber Katharina
Published: January 2015

Protein adsorption and blood coagulation play important roles in the early stages of osseointegration and are strongly influenced by surface properties. We present a systematic investigation of the influence of different surface properties on the adsorption of the blood proteins fibrinogen and fibronectin and the degree of early blood coagulation. Experiments on custom‐made and commercially available, microroughened hydrophobic titanium (Ti) surfaces (Ti SLA‐Hphob), hydrophilic (Hphil) microroughened Ti surfaces with nanostructures (Ti SLActive‐HphilNS), and on bimetallic Ti zirconium alloy (TiZr, Roxolid®) samples were performed, to study the biological response in relation to the surface wettability and the presence of nanostructures (NS). Protein adsorption on the different substrates showed a highly significant effect of surface NS. Hydrophilicity alone did not significantly enhance protein adsorption. Overall, the combination of NS and hydrophilicity led to the highest adsorption levels; independent of whether Ti or TiZr were used. Hydrophilicity induced a strong effect on blood coagulation, whereas the effect of NS alone was weak. The combination of both surface characteristics led to early and most pronounced blood‐coagulation. Therefore, nanostructured, hydrophilic Ti and TiZr surfaces may perform better in terms of osseointegration due to continuous protein adsorption and the formation of a layer of blood components on the implant surface. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 2661–2672, 2015.
Biomimetic surface modification of polyurethane with phospholipids grafted carbon nanotubes
Authors: Tan Dongsheng , Liu Liuxu , Li Zhen , Fu Qiang
Published: January 2015

To improve blood compatibility of polyurethane (PU), phospholipids grafted carbon nanotubes (CNTs) were prepared through zwitterion‐mediated cycloaddition reaction and amide condensation, and then were added to the PU as fillers via solution mixing to form biomimetic surface. The properties of phospholipids grafted CNTs (CNT‐PC) were investigated by thermal gravimetric analysis (TGA), X‐ray photoelectron spectroscopy (XPS) and proton nuclear magnetic resonance (1H NMR). The results indicated that the phospholipids were grafted onto CNTs in high efficiency, and the hydrophilicity and dispersibility of the modified CNTs were improved effectively. The structures and properties of composites containing CNT‐PC were investigated by optical microscope, XPS, and water contact angles. The results indicated that phospholipids were enriched on the surface with addition of 0.1 wt % of CNT‐PC, which significantly reduced protein adsorption and platelet adhesion. The method of carrying phospholipids on the nanofiller to modify polymers has provided a promising way of constructing biomimetic phospholipid membrane on the surface to improve blood compatibility. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 2711–2719, 2015.
Optimization of the time efficient calcium phosphate coating on electrospun poly(d,l‐lactide)
Authors: Luickx Nathalie , Van Den Vreken Natasja , Segaert Jonas , Declercq Heidi , Cornelissen Maria , Verbeeck Ronald
Published: January 2015

The coating of fibrous polyester constructs with a layer of bioactive calcium phosphate (CP) is efficient to improve the potential use as bone tissue engineering scaffold. In this study, a fast procedure for the coating of electrospun poly(d,l‐lactide) (PDLLA) fibers with a CP layer was optimized. The fiber surface was activated by immersion in demineralized water under ultrasonication. The resulting reactive groups served as nucleation points for CP precipitation, induced by alternate dipping of the samples in Ca2+ and PO43− rich solutions. Variations in the conditions of the alternate dipping procedure, in particular the number of cycles, concentration and immersion time of both solutions, not only affected the degree of surface mineralization but also the type of deposited CP. For the current experimental conditions, in about 30 minutes either a slightly carbonated calcium deficient apatite (CDAp; Ca10‐x‐y(PO4)6‐x‐y(HPO4)y (CO3)x(OH)2‐x‐y) or a combination of apatite and dicalcium phosphate dihydrate (DCPD; CaHPO4.2H2O) was formed. The cell viability, adhesion, and proliferation of MC3T3‐E1 cells on untreated samples were compared with samples coated with either an adequate amount of CDAp, an excess of CDAp or an excess of a combination of apatite and DCDP. After 7 days of culture the number of attached cells was significantly higher on all CP coated samples compared to the untreated PDLLA. In particular, the samples coated with an adequate amount of CDAp showed an exceedingly enhanced cell response with similar cell morphologies as the ones found on the positive control. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 2720–2730, 2015.