bluuebunny/crossref_metadata_2025_split huggingface dataset:
KINETIC MODELS ON ACETYLCHOLINESTERASE MODULATION BY SELF-SUBSTRATE AND POLYAMINES: ESTIMATION OF INTERACTION PARAMETERS AND RATE CONSTANTS FOR FREE AND ACETYLATED STATES OF THE ENZYME
Authors: VENTURINO ANDRÉS , BERGOC ROSA MARÍA , DE D'ANGELO ANA MARÍA PECHEN , ROSENBAUM ENRIQUE ARTURO 
Published: July 2002

Polyamines act as dual modulators on electric eel acetylcholinesterase, modifying both the apparent Km and Ki, depending on substrate levels. A kinetic model was developed to explain the results, based on two-step catalysis, a peripheral site for substrate inhibition apart from the catalytic site, and one binding site for polyamine. This model presented the best fittings to data, when compared with a simpler one considering one catalytic step. A fitting equation built up with sixteen independent parameters let us calculate the kinetic constants. In this way, we were able to solve the parameter identifiability problem arising from model uncertainty when only substrate was used in acetylcholinesterase kinetics. Besides, fitting parameters directly provide information about the binding constants of the different complexes, the modulatory strength of substrate and polyamines, and the effect on the standard activation free energy for acetylcholinesterase.Substrate inhibition operates mainly on the first catalytic step with an affinity constant of 5.2 mM-1, which is reduced to one third for the acetylated enzyme. The interaction factor between substrate binding at both sites is about 12. The modulatory strength of polyamines is spermine > spermidine > putrescine. This order is directly related to the number of amino groups in the molecule, and to the calculated free interaction energy. The effect of the number of amino groups on the binding energy is significantly increased in acetylated acetylcholinesterase. It is also inferred that the formation of a quaternary complex enzyme-substrate-substrate-polyamine would not be possible. Some relations between polyamine structure and acetylcholinesterase activity are suggested from estimated constants. Due to the distal amino group distances, it is possible for spermine and spermidine to span along the catalytic gorge of acetylcholinesterase, binding to the catalytic and peripheral sites in a way similar to bisquaternary ammonium inhibitors.
MARKOV PROCESS IN PATTERN RECOGNITION
Authors: CAI JINHAI , LIU ZHI-QIANG 
Published: July 2002

Using the Markov random process, we developed two new approaches to pattern recognition: (1) Hidden Markov model for modeling spectral features for recognizing 2D shapes. This is because Fourier spectra are suitable for describing 2D shapes of simple closed contours and probabilistic models are capable of coping with random variations in object shapes. We will analyze the properties of spectral features derived from contours of 2D shapes and use these features in 2D pattern recognition. (2) Markov random fields for modeling 2D structural and statistical features. We will give a theoretic analysis of this approach, discuss the issues in the design of neighborhood system and cliques for Markov random field models, and analyze the properties of the models. We have applied the proposed approach to the recognition of unconstrained handwritten numerals and 2D shapes. Our extensive experimental results show that the proposed approach can achieve a higher performance than that reported recently in the literature.
Toward automatic program synthesis
Authors: Manna Zohar , Waldinger Richard J. 
Published: July 2002

An elementary outline of the theorem-proving approach to automatic program synthesis is given, without dwelling on technical details. The method is illustrated by the automatic construction of both recursive and iterative programs operating on natural numbers, lists, and trees.
In order to construct a program satisfying certain specifications, a theorem induced by those specifications is proved, and the desired program is extracted from the proof. The same technique is applied to transform recursively defined functions into iterative programs, frequently with a major gain in efficiency.
It is emphasized that in order to construct a program with loops or with recursion, the principle of mathematical induction must be applied. The relation between the version of the induction rule used and the form of the program constructed is explored in some detail.
Tablet: personal computer of the year 2000
Authors: Mel B. W. , Omohundro S. M. , Robison A. D. , Skiena S. S. , Thearling K. H. 
Published: July 2002

A design represents a compromise between conflicting goals, and the design of the personal computer of the year 2000 is no exception. We seek something that will fit comfortably into people's lives while dramatically changing them. This may appear to be a contradiction that cannot be reconciled. But if the technology does not fit easily into the habits and lifestyles of its human users, it will be discarded by those it was meant to help. And if this new tool does not change the life of its owner, it is only because we have been too shortsighted to imagine the possibilities.
Our way out of this dilemma is to base the design upon something which is already integrated into everyone's life, to take a vital tool and give it more life. We have chosen to improve something that most people use everyday, the humble paper notebook.
We have all heard the computer revolution was supposed to eliminate paper from the workplace. Instead, it has lead to desktop publishing; now we can not only write papers but typeset them ourselves. Paper notebooks have many properties that make them particularly friendly. They are light and portable. No one thinks twice about taking a pad anywhere. They are easy and natural to use, as accessible to the toddler as to the octogenarian and as relevant to the artist as the engineer. They can be used to communicate with other people. They are the ideal medium for integrating text and graphics, and perfect for creative doodling. Moreover, notebooks are forgiving of mistakes, simply peel off the page and start anew.
It is natural to revise and edit written documents. There is something satisfying about crossing out an offending sentence from a written draft, a feeling that word processors have not captured. We aim for a computer that will provide all of these benefits and more.
Thus, the personal computer of the year 2000 will be a portable machine the size of a notebook. We will write and draw with a stylus on a screen which mimics a physical writing surface. Enhancing this with the powers of computation and communication, we create a tool that will improve the way we live and work.
This report provides a more concrete depiction of the machine we have in mind, namely TABLET.
Temporal Allocation of Visual Attention in Adult Attention Deficit Hyperactivity Disorder.
Authors: Hollingsworth Deidre E. , McAuliffe Sean P. , Knowlton Barbara J. 
Published: July 2002

Abstract
In two experiments, we examined the ability of adults with attention deficit hyperactivity disorder (ADHD) to preocess multiple targets appearing in a rapid serial visual presentation (RSVP) stream. Using a standard attentional blink (AB) task, subjects were required to both identify a target in the RSVP stream and detect a probe appearing in one of several posttarget serial positions. In Experiment 1, ADHD adults exhibited a protracted AB compared to controls, in that their probe detection did not improve as a function of increasing probe-to-target intervals (450-720 msec). In Experiment 2, the ADHD group performed as well as controls in detectin probes appearing immediately (i.e., 90 msec) after the target. Taken together, the results demonstrate that adults with ADHD exhibit a selective deficit in rapidly shifting attention between the target and the probe, when two appear several hundred milliseconds apart. These results suggest that adults with ADHD can use automatic (reflexive) attention to detect items in close temporal proximity in the RSVP stream, but have difficulty allocating controlled attention to multiple stimuli separated by several hundred milliseconds.
RESPONSE TO THOMAS BERRY'S THE GREAT WORK
Authors: Radford Ruether Rosemary 
Published: July 2002

AbstractIn this commentary on Thomas Berry's recent book, The Great Work, Rosemary Radford Ruether argues that the transformation that is needed to achieve a sustainable society must contain a dynamic interaction of three components: transformation of consciousness and culture, transformation of technology and transformation of social, legal and economic relations between humans. There cannot be a focus on only one or two of these components at the expense of the other(s). The transformation of culture and consciousness includes a profound deconstruction of the patterns of hierarchical dualism in Western theological, philosophical, psychology and scientific thought and their reconstruction in terms of relations of dynamic mutuality.
Growth, sexual dimorphism, and population biology of the olive sea snake, Aipysurus laevis, on the Great Barrier Reef of Australia
Authors: Burns Glen , Heatwole Harold 
Published: July 2002

AbstractThe olive sea snake, Aipysurus laevis (Lacépède) grows at a rate of 0.22-0.95 cm/month, with young animals growing faster than older ones. Males reach sexual maturity in their third year and females in their fourth or fifth year. There is sexual dimorphism in size, with females larger than males; at snout-vent lengths greater than 80 cm, females are heavier than males of equivalent length. Small snakes were uncommon. Apparent sexratio favours males in winter but moves toward equality or even a preponderance of females in summer, probably reflecting changes in reproductive behaviour. Numbers of snakes are approximately 0.70-0.86 snakes per metre of reef edge. Olive sea snakes live to about 15 years or older.
OPPORTUNITIES FOR VISUAL EXPERIENCE WHICH MIGHT ALLOW IMPRINTING IN CHICKS RAISED BY BROODY HENS
Authors: Workman  , Adam  , Andrew R.J. 
Published: July 2002

Abstract
Chicks raised by a broody hen can see social fellows (mother, sibs) to whom they might attach, only during emergence from under the mother. Chicks raised by a hen showed longest emergences when in broods of 1-2, shortest in broods of 3-4 and longer again in broods > 4. As a result, the first visual experience of any length was on day 2 for broods > 4 and on day 3 for broods of 3-4. Mean duration/chick was 45-50 min in both cases, comparable to times found to give attachment to models. The mother's moving (and often calling) head must be a dominant visual feature for chicks: they most commonly emerge from under the breast and are at once confronted by it. When they emerge from under the wings, the mother turns the head to them, and they then accompany it back to the breast, where they nearly always re-enter. The first experience of the mother in translatory motion on day 5 is so different from this that it probably leads to further learning. Chicks reared in groups without a mother learn to discriminate sibs from strangers. If this occurs in normal broods, it could begin in the group emergences, which are usual on day 3.
THE DESIGN AND PRODUCTION OF A SEXUAL SIGNAL: HOODS AND HOOD BUILDING BY MALE FIDDLER CRABS UCA MUSICA
Authors: Christy John , Backwell Patricia R.Y. , Goshima Seiji 
Published: July 2002

Abstract
Courting male fiddler crabs Uca musica sometimes build hoods at the entrances of their burrows to which females come for mating. Females differentially orient to burrows with hoods and thereby show a mate preference for hood builders. Here we describe how this mode of sexual selection may affect hood design and building. Larger males built generally larger but not higher hoods. Small males may build relatively high hoods so that they will be conspicuous to females of all sizes and construction or other costs may limit hood height. Most males built only one hood each biweekly reproductive cycle, typically on a day that many females chose mates, and they finished construction before females began mate searching. Both patterns fit predictions based on applying ideal free theory to the timing of sexual signaling. Sexual selection may favor more frequent hood building but the timing of hood building appears to be optimal.
Photochromism of azobenzene in the hydrophobic interlayer spaces of dialkyldimethylammonium-fluor-tetrasilicic mica films
Authors: Ogawa M. , Hama M. , Kuroda K. 
Published: July 2002

AbstractPhotochemical isomerization of azobenzene intercalated in the hydrophobic, interlayer spaces of swelling fluor-tetrasilicic micas exchanged with dialkyldimethylammonium ions, with the alkyl chain length from 10 to 18, was investigated. Thin films of the organoammonium-mica-azobenzene intercalation compounds were obtained by depositing a suspension of the organoammonium-micas (prepared using a toluene/methanol solution of azobenzene) on quartz substrates. The intercalated azobenzene showed reversible photochromic reactions induced by UV and visible light irradiation. The fraction of the photochemically formed cis-isomer in the photostationary states decreased with a decrease in temperature. The observed change in the photochemical reactions is thought to reflect changes in the states of the dialkyldimethylammonium ions in the interlayer space of the swelling fluor-tetrasilicic mica.
Ristocetin-dependent, but not botrocetin-dependent, binding of von Willebrand factor to the platelet glycoprotein Ib-IX-V complex correlates with shear-dependent interactions
Authors: Dong Jing-Fei , Berndt Michael C. , Schade Alicia , McIntire Larry V. , Andrews Robert K. , López José A. 
Published: July 2002

AbstractUnder conditions of high shear stress, both hemostasis and thrombosis are initiated by the interaction of the platelet membrane glycoprotein (GP) Ib-IX-V complex with its adhesive ligand, von Willebrand factor (vWF), in the subendothelial matrix or plasma. This interaction involves the A1 domain of vWF and the N-terminal extracellular region of GP Ibα (His-1-Glu-282), and it can also be induced under static conditions by the modulators ristocetin and botrocetin. In this study, a panel of anti-vWF and anti-GP Ibα antibodies—previously characterized for their effects on ristocetin- and botrocetin-dependent vWF–GP Ib-IX-V interactions—was analyzed for their capacity to inhibit either the adhesion of Chinese hamster ovary cells expressing recombinant GP Ibα to surface-associated vWF under hydrodynamic flow or shear-stress–induced platelet aggregation. The combined results suggest that the shear-dependent interactions between vWF and GP Ibα closely correlate with ristocetin- rather than botrocetin-dependent binding under static conditions and that certain anti-vWF monoclonal antibodies are able to selectively inhibit shear-dependent platelet aggregation.
Targeting of a B7-1 (CD80) immunoglobulin G fusion protein to acute myeloid leukemia blasts increases their costimulatory activity for autologous remission T cells
Authors: Notter Michael , Willinger Tim , Erben Ulrike , Thiel Eckhard 
Published: July 2002

AbstractTransfection of tumor cells with the gene encoding the costimulatory molecule B7-1 (CD80), the ligand for CD28 and cytotoxic T lymphocye antigen-4 on T cells, has been shown to result in potent T-cell–mediated antitumor immunity. As an alternative approach, this study analyzed the costimulatory capacity of a human B7-1 immunoglobulin G (IgG) fusion protein targeted to the cell membrane of human acute myeloid leukemia (AML) blasts. Flow cytometric analysis revealed a low constitutive expression of B7-1 on human AML blasts (on average, 3.0 ± 4.3%; n = 50). In contrast, the expression of B7-2 (CD86) was highly heterogeneous and higher in AML blasts of French-American-British classification types M4 and M5 (P &lt; .0001). The B7-1 IgG fusion protein used in this study efficiently costimulated the proliferation of resting and preactivated T cells when immobilized on plastic. After preincubation with B7-1 IgG, specific binding of the fusion protein to the high-affinity Fcγreceptor I (CD64) on leukemic cells was demonstrated and was found to increase the proliferation of both allogeneic and autologous T cells in costimulation experiments. Furthermore, targeting of B7-1 IgG to the tumor membrane resulted in increased proliferation of autologous remission T cells and had the potential to generate an enhanced redirected cytotoxic T-cell response against autologous AML blasts. In summary, the targeting of B7-1 IgG fusion protein described in this study represents a strategy alternative to gene therapy to restore the expression of the costimulatory molecule B7-1 on human AML blasts, thereby enhancing their immunogenicity for autologous T cells. This new approach may have implications for T-cell–mediated immunotherapy in AML.
CD13/APN is activated by angiogenic signals and is essential for capillary tube formation
Authors: Bhagwat Shripad V. , Lahdenranta Johanna , Giordano Ricardo , Arap Wadih , Pasqualini Renata , Shapiro Linda H. 
Published: July 2002

AbstractIn the hematopoietic compartment, the CD13/APN metalloprotease is one of the earliest markers of cells committed to the myeloid lineage where it is expressed exclusively on the surface of myeloid progenitors and their differentiated progeny. CD13/APN is also found in nonhematopoietic tissues, and its novel expression on the endothelial cells of angiogenic, but not normal, vasculature was recently described. Treatment of animals with CD13/APN inhibitors significantly impaired retinal neovascularization, chorioallantoic membrane angiogenesis, and xenograft tumor growth, indicating that CD13/APN plays an important functional role in vasculogenesis and identifying it as a critical regulator of angiogenesis. To investigate the mechanisms of CD13/APN induction in tumor vasculature, the regulation ofCD13/APN by factors contributing to angiogenic progression was studied. In this report, it is shown that endogenous CD13/APN levels in primary cells and cell lines are up-regulated in response to hypoxia, angiogenic growth factors, and signals regulating capillary tube formation during angiogenesis. Transcription of reporter plasmids containing CD13/APNproximal promoter sequences is significantly increased in response to the same angiogenic signals that regulate the expression of the endogenous gene and in human tumor xenografts, indicating that this fragment contains elements essential for the angiogenic induction ofCD13/APN expression. Finally, functional antagonists of CD13/APN interfere with tube formation but not proliferation of primary vascular endothelial cells, suggesting that CD13/APN functions in the control of endothelial cell morphogenesis. These studies clearly establish the CD13/APN metalloprotease as an important regulator of endothelial morphogenesis during angiogenesis.
Assembly of a fibronectin matrix by adherent platelets stimulated by lysophosphatidic acid and other agonists
Authors: Olorundare Olufunke E. , Peyruchaud Olivier , Albrecht Ralph M. , Mosher Deane F. 
Published: July 2002

AbstractLysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are agonists of the endothelial differentiation gene (Edg) family of G-protein–coupled receptors. LPA and S1P are generated by platelet activation during blood coagulation. Both lipids induce assembly of exogenous fibronectin (FN) by fibroblasts. This study examined whether LPA and S1P stimulate binding and assembly of fluoresceinated FN (FITC-FN) by adherent platelets. LPA enhanced deposition of FITC-FN into linear arrays overlying platelet surfaces and on edges of platelets adherent to FN or vitronectin (VN). Deposition was greater when platelets were adherent to FN than to VN and was elicited by platelet agonists with the following order of potency: thrombin &gt; LPA = ADP (adenosine diphosphate) &gt; S1P. The linear pattern of FITC-FN deposition was different from the more diffuse pattern of Alexa-fibrinogen (Alexa-FGN) binding to adherent platelets. FITC-FN was deposited by adherent platelets that had dense arrays of cytoskeletal actin when stained with rhodamine-phalloidin. The 70-kd N-terminal fragment of FN or L8 monoclonal antibody to a self-association domain of FN abolished deposition of FITC-FN but had no effect on binding of Alexa-FGN. Conversely, integrilin did not attenuate deposition of FITC-FN but abolished binding of Alexa-FGN. RGDS (Arg-Gly-Asp-Ser) or antibodies to α5β1 or αIIbβ3 integrins caused a partial decrease in LPA-induced deposition of FITC-FN. Correlative electron microscopy with anti-FITC coupled to gold beads revealed linear arrays on platelet surfaces associated with less than 20-nm–diameter filaments. These observations demonstrate that LPA, thrombin, ADP, and S1P induce adherent platelets to bind and assemble FN and suggest that platelets may contribute to early deposition of FN matrix after vascular injury.
Reduced blood CD123+ (lymphoid) and CD11c+ (myeloid) dendritic cell numbers in primary HIV-1 infection
Authors: Pacanowski Jérôme , Kahi Sandrine , Baillet Marjorie , Lebon Pierre , Deveau Christiane , Goujard Cécile , Meyer Laurence , Oksenhendler Eric , Sinet Martine , Hosmalin Anne 
Published: July 2002

AbstractSuccessful immunologic control of HIV infection is achieved only in rare individuals. Dendritic cells (DCs) are required for specific antigen presentation to naive T lymphocytes and for antiviral, type I interferon secretion. Two major blood DC populations are found: CD11c+ (myeloid) DCs, which secrete IL-12, and CD123+ (IL-3–receptor+) DCs (lymphoid), which secrete type I interferons in response to viral stimuli. The authors have previously found a decreased proportion of blood CD11c+ DCs in chronic HIV+ patients. In this study, 26 to 57 days after infection and before treatment, CD123+ and CD11c+ DC numbers were dramatically reduced in 13 HIV+ patients compared with 13 controls (P = .0002 and P = .001, respectively). After 6 to 12 months of highly active antiretroviral therapy, DC subpopulation average numbers remained low, but CD123+ DC numbers increased again in 5 of 13 patients. A strong correlation was found between this increase and CD4 T-cell count increase (P = .0009) and plasma viral load decrease (P = .009). Reduced DC numbers may participate in the functional impairment of HIV-specific CD4+ T cells and be responsible for the low type I interferon responsiveness already known in HIV infection. The restoration of DC numbers may be predictive of immune restoration and may be a goal for immunotherapy to enhance viral control in a larger proportion of patients.
Role of 4 platelet membrane glycoprotein polymorphisms on experimental arterial thrombus formation in men
Authors: Cadroy Yves , Sakariassen Kjell S. , Charlet Jean-Paul , Thalamas Claire , Boneu Bernard , Sie Pierre 
Published: July 2002

Abstract
This study investigates whether the polymorphisms of 3 important platelet receptors affected experimental thrombus formation in men. Forty healthy male volunteers randomly recruited were genotyped for the variable number of tandem repeat (VNTR) of GPIbα, the −5T/C polymorphism in the Kozak sequence of GPIbα, the 807C/T polymorphism of GPIa, and the PlA1/PlA2polymorphism of GPIIb/IIIa. Platelet thrombus formation was induced ex vivo by exposing a collagen-coated coverslip in a parallel plate perfusion chamber to native blood for 4 minutes. The shear rates at the collagen surface were 650 and 2600 s−1. At 2600 s−1 platelet thrombus formation was significantly related only to the 807C/T polymorphism. In contrast, at 650 s−1thrombus formation was significantly altered only by the Kozak sequence polymorphism. The VNTR and the PlA1/PlA2polymorphisms did not influence thrombus formation. Thus, platelet thrombus formation is significantly influenced by genetic variations of the GPIbα and GPIa receptors. The effect of these polymorphisms was dependent on the blood flow rate.