Showing papers by "State University of New York System published in 1994"

Determinants of Long-Term Orientation in Buyer-Seller Relationships:

Abstract: Marketing managers must know the time orientation of a customer to select and use marketing tools that correspond to the time horizons of the customer. Insufficient understanding of a customer's ti...

Requirement of vascular integrin alpha v beta 3 for angiogenesis

Abstract: Angiogenesis depends on the adhesive interactions of vascular cells. The adhesion receptor integrin alpha v beta 3 was identified as a marker of angiogenic vascular tissue. Integrin alpha v beta 3 was expressed on blood vessels in human wound granulation tissue but not in normal skin, and it showed a fourfold increase in expression during angiogenesis on the chick chorioallantoic membrane. In the latter assay, a monoclonal antibody to alpha v beta 3 blocked angiogenesis induced by basic fibroblast growth factor, tumor necrosis factor-alpha, and human melanoma fragments but had no effect on preexisting vessels. These findings suggest that alpha v beta 3 may be a useful therapeutic target for diseases characterized by neovascularization.

A database for handwritten text recognition research

Abstract: An image database for handwritten text recognition research is described. Digital images of approximately 5000 city names, 5000 state names, 10000 ZIP Codes, and 50000 alphanumeric characters are included. Each image was scanned from mail in a working post office at 300 pixels/in in 8-bit gray scale on a high-quality flat bed digitizer. The data were unconstrained for the writer, style, and method of preparation. These characteristics help overcome the limitations of earlier databases that contained only isolated characters or were prepared in a laboratory setting under prescribed circumstances. Also, the database is divided into explicit training and testing sets to facilitate the sharing of results among researchers as well as performance comparisons. >

Decision combination in multiple classifier systems

Abstract: A multiple classifier system is a powerful solution to difficult pattern recognition problems involving large class sets and noisy input because it allows simultaneous use of arbitrary feature descriptors and classification procedures. Decisions by the classifiers can be represented as rankings of classifiers and different instances of a problem. The rankings can be combined by methods that either reduce or rerank a given set of classes. An intersection method and union method are proposed for class set reduction. Three methods based on the highest rank, the Borda count, and logistic regression are proposed for class set reranking. These methods have been tested in applications of degraded machine-printed characters and works from large lexicons, resulting in substantial improvement in overall correctness. >

Levels Issues in Theory Development, Data Collection, and Analysis

Abstract: Despite past entreaties to organizational theorists and researchers to address levels issues more carefully, levels issues continue to arouse confusion and controversy within the organizational literature. We highlight three alternative assumptions that underlie the specification of levels of theory throughout organizational behavior: (a) homogeneity within higher level units, (b) independence from higher level units, and (c) heterogeneity within higher level units. These assumptions influence the nature of theoretical constructs and propositions and should, ideally, also influence data collection, analysis, and interpretation. Greater attention to levels issues will strengthen organizational theory development and research.

Anatomical evidence for cerebellar and basal ganglia involvement in higher cognitive function

Abstract: The possibility that neurons in the basal ganglia and cerebellum innervate areas of the cerebral cortex that are involved in cognitive function has been a controversial subject. Here, retrograde transneuronal transport of herpes simplex virus type 1 (HSV1) was used to identify subcortical neurons that project via the thalamus to area 46 of the primate prefrontal cortex. This cortical area is known to be involved in spatial working memory. Many neurons in restricted regions of the dentate nucleus of the cerebellum and in the internal segment of the globus pallidus were labeled by transneuronal transport of virus from area 46. The location of these neurons was different from those labeled after HSV1 transport from motor areas of the cerebral cortex. These observations define an anatomical substrate for the involvement of basal ganglia and cerebellar output in higher cognitive function.

Assessment of risk for periodontal disease. I. Risk indicators for attachment loss.

Abstract: Specific risk indicators associated with either susceptibility or resistance to severe forms of periodontal disease were evaluated in a cross-section of 1,426 subjects, 25 to 74 years of age, mostly metropolitan dwellers, residing in Erie County, New York, and surrounding areas. The study sample exhibited a wide range of periodontal disease experience defined by different levels of attachment loss. Therefore, it was possible to accurately assess associations between the extent of periodontal disease and patient characteristics including age, smoking, systemic diseases, exposure to occupational hazards, and subgingival microbial flora. Age was the factor most strongly associated with attachment loss, with odds ratios for subjects 35 to 44 years old ranging from 1.72 (95% CI: 1.18 to 2.49) to 9.01 (5.86 to 13.89) for subjects 65 to 74 years old. Diabetes mellitus was the only systemic disease positively associated with attachment loss with an odds ratio of 2.32 (95% CI: 1.17–4.60). Smoking had relative risk...

Fractal Cities: A Geometry of Form and Function

Abstract: Planners and architects will find that many aspects of fractal geometry covered in this book are relevant to their own interests.

Biological magnetic resonance imaging using laser-polarized 129Xe

Abstract: As currently implemented, magnetic resonance imaging (MRI) relies on the protons of water molecules in tissue to provide the NMR signal. Protons are, however, notoriously difficult to image in some biological environments of interest, notably the lungs and lipid bilayer membranes such as those in the brain. Here we show that 129Xe gas can be used for high-resolution MRI when the nuclear-spin polarization of the atoms is increased by laser optical pumping and spin exchange. This process produces hyperpolarized 129Xe, in which the magnetization is enhanced by a factor of about 10(5). By introducing hyperpolarized 129Xe into mouse lungs we have obtained images of the lung gas space with a speed and a resolution better than those available from proton MRI or emission tomography. As xenon (a safe general anaesthetic) is rapidly and safely transferred from the lungs to blood and thence to other tissues, where it is concentrated in lipid and protein components, images of the circulatory system, the brain and other vital organs can also be obtained. Because the magnetic behaviour of 129Xe is very sensitive to its environment, and is different from that of 1H2O, MRI using hyperpolarized 129Xe should involve distinct and sensitive mechanisms for tissue contrast.

Procalcitonin increase after endotoxin injection in normal subjects.

Abstract: As procalcitonin concentrations have been shown to be elevated in patients with septicemia and gram-negative infections in particular, we proceeded to investigate the effect of endotoxin, a product of gram-negative bacteria, on procalcitonin concentrations in normal human volunteers Endotoxin from Escherichia coli 0113:H10:k, was injected iv at a dose of 4 mg/kg BW into these healthy volunteers Blood samples were obtained before and 1, 2, 4, 6, 8, and 24 h after injection of the endotoxin Each patient's cardiovascular and overall clinical status was monitored over this period The patients developed chills and rigors, myalgia, and fever between 1-3 h Tumor necrosis factor-alpha levels increased sharply at 1 h and peaked at 90 min, reaching the baseline concentration thereafter by 6 h Interleukin-6 levels increased more gradually, peaking at 3 h and reaching the baseline concentration at 8 h The procalcitonin concentration, which was undetectable (< 10 pg/mL) at 0, 1, and 2 h, was detectable at 4 h

Delinquent peers, beliefs, and delinquent behavior: a longitudinal test of interactional theory*

Abstract: Three theoretical models of the interrelations among associations with delinquent peers, delinquent beliefs, and delinquent behavior are examined. The socialization model views delinquent peers and beliefs as causally prior to delinquent behavior, whereas the selection model hypothesizes that associations with delinquent peers and delinquent beliefs are a result of delinquent behavior. The interactional model combines aspects of both the socialization and the selection models, positing that these variables have bidirectional causal influences on one another over time. Data to test for reciprocal causality are drawn from three waves of the Rochester Youth Development Study. Results suggest that simple unidirectional models are inadequate. Associating with delinquent peers leads to increases in delinquency via the reinforcing environment of the peer network. Engaging in delinquency, in turn, leads to increases in associations with delinquent peers. Finally, delinquent beliefs exert lagged effects on peers and behavior, which tend in turn to “harden” the formation of delinquent beliefs.

The Barbados Eye Study. Prevalence of open angle glaucoma

Abstract: Objective: To describe the design of the Barbados Eye Study and report on the prevalence of open angle glaucoma (OAG) in a predominantly black study population. Design: Population-based prevalence study. Setting and Participants: Residents of Barbados, West Indies, identified from a simple random sample of Barbadian-born citizens 40 through 84 years old. Data Collection: Participants had a comprehensive study visit that included automated perimetry, applanation tonometry, and fundus photography; persons with specific examination findings, as well as a 10% sample of participants, were referred for an ophthalmologic examination and additional tests. Outcome: A diagnosis of OAG required both visual field and optic disc criteria for glaucoma damage after excluding other causes. Results: The 4709 participants (83.5% of those eligible) had demographic characteristics that were similar to the census population. Of the 4631 participants who were tested at the study site, 95% completed Humphrey automated perimetry and 97% had photographic or clinical disc gradings; 93% of those referred completed the ophthalmologic examination. In this adult population, the prevalence of OAG by self-reported race was 7.0% (302/4314) in black, 3.3% (6/184) in mixed-race, and 0.8% (1/133) in white or other participants. In black and mixedrace participants, the prevalence reached 12% at age 60 years and older and was higher in men (8.3%) than in women (5.7%), with an age-adjusted male-female ratio of 1.4. In addition, over 3% of the participants were classified as having suspect OAG. Conclusions: To our knowledge, the Barbados Eye Study is the largest glaucoma study ever conducted in a black population and identified more people with OAG than did any previous population study. The prevalence of OAG was high, especially at older ages and in men. Among participants 50 years old or older, one in 11 had OAG, and prevalence increased to one in six at age 70 years or older. The results highlight the public health importance of OAG in the Afro-Caribbean region and have implications for other populations.

Nonspecific interstitial pneumonia/fibrosis. Histologic features and clinical significance

Abstract: Sixty-four cases of interstitial pneumonia were identified that could not be classified into one of three main categories of idiopathic interstitial pneumonia. These cases, descriptively termed nonspecific interstitial pneumonia/fibrosis, were characterized by varying proportions of interstitial inflammation and fibrosis that appeared to be occurring over a single time span (i.e., the process was temporally uniform.) The most common presenting complaint was dyspnea for several months, and chest radiographs usually showed bilateral interstitial infiltrates. The prognosis was good with only five deaths due to progressive respiratory disease in 48 patients with known follow-up (11%). No deaths occurred in patients whose biopsies showed pure inflammation and no fibrosis. Nonspecific interstitial pneumonia must be separated from the three main forms of idiopathic interstitial pneumonia because of better prognosis and different treatment options. It should not be considered a specific disease, however, because it may have varying etiologies including underlying connective tissue diseases, organic dust or other exposures, and prior acute lung injury; less often, it may reflect a nonrepresentative biopsy of another process.

Interrater reliability of the 7-level functional independence measure (FIM)

Abstract: The Functional Independence Measure (FIM) is an 18-item, 7-level scale developed to uniformly assess severity of patient disability and medical rehabilitation functional outcome. FIM interrater reliability in the clinical setting is reported here. Clinicians from 89 US inpatient comprehensive medical rehabilitation facilities newly subscribing to the uniform Data System for Medical Rehabilitation from January 1988-June 1990 evaluated 1018 patients with the FIM. FIM total, domain and subscale score intraclass correlation coefficients (ICC) were calculated using ANOVA; FIM item score agreement was assessed with unweighted Kappa coefficient. Total FIM ICC was 0.96; motor domain 0.96 and cognitive domain 0.91; subscale score range: 0.89 (social cognition) to 0.94 (self-care). FIM item Kappa range: 0.53 (memory) to 0.66 (stair climbing). A subset of 24 facilities meeting UDSMR data aggregation reliability criteria had Intraclass and Kappa coefficients exceeding those for all facilities. It is concluded that the 7-level FIM is reliable when used by trained/tested inpatient medical rehabilitation clinicians.

Negative Feedback Defining a Circadian Clock: Autoregulation of the Clock Gene Frequency

Abstract: The frequency (frq) locus of Neurospora crassa was originally identified in searches for loci encoding components of the circadian clock. The frq gene is now shown to encode a central component in a molecular feedback loop in which the product of frq negatively regulated its own transcript, which resulted in a daily oscillation in the amount of frq transcript. Rhythmic messenger RNA expression was essential for overt rhythmicity in the organism and no amount of constitutive expression rescued normal rhythmicity in frq loss-of-function mutants. Step reductions in the amount of FRQ-encoding transcript set the clock to a specific and predicted phase. These results establish frq as encoding a central component in a circadian oscillator.

Activation of a cerebellar output nucleus during cognitive processing.

Abstract: Magnetic resonance imaging was used to examine the involvement of the dentate nucleus of the cerebellum in cognitive operations. All seven people examined displayed a large bilateral activation in the dentate during their attempts to solve a pegboard puzzle. The area activated was three to four times greater than that activated during simple movements of the pegs. These results provide support for the concept that the computational power of the cerebellum is applied not only to the control of movement but also to cognitive functions.

Depth from defocus: a spatial domain approach

Abstract: A new method named STM is described for determining distance of objects and rapid autofocusing of camera systems. STM uses image defocus information and is based on a new Spatial-Domain Convolution/Deconvolution Transform. The method requires only two images taken with different camera parameters such as lens position, focal length, and aperture diameter. Both images can be arbitrarily blurred and neither of them needs to be a focused image. Therefore STM is very fast in comparison with Depth-from-Focus methods which search for the lens position or focal length of best focus. The method involves simple local operations and can be easily implemented in parallel to obtain the depth-map of a scene. STM has been implemented on an actual camera system named SPARCS. Experiments on the performance of STM and their results on real-world planar objects are presented. The results indicate that the accuracy of STM compares well with Depth-from-Focus methods and is useful in practical applications. The utility of the method is demonstrated for rapid autofocusing of electronic cameras.

Synchrotron computed microtomography of porous media: Topology and transports.

Abstract: Computed microtomography is applied to a piece of Fontainebleau sandstone in order to determine the geometrical structure of the pores. The topology of the void space is then derived from the tomographic image of the volume. Permeability and conductivity are computed and found in good agreement with experimental data. Perspectives offered by this new nondestructive method with a potential resolution of the order of one micrometer or less are analyzed.

Comparing self-reported and physician-reported medical history.

Abstract: The authors compared self-reported medical history and medication use in a cataract case-control study of 1,380 persons (1985-1989) in Boston, Massachusetts, with information from the participants' physicians. Under- and overreporting varied by condition and type of medication. A self-reported history of hypertension had the highest sensitivity (91%), and diabetes history had the highest specificity (97%). Among different medications investigated, self-reported antihypertensive medication use was the most sensitive (88%), while self-reported use of insulin was the most specific (99%). Differences between patient- and physician-reported frequencies were very small, except for arthritis (15%) and regular aspirin use (21%). Results suggest an accurate recall of medical and drug usage history in well-defined chronic conditions.

Two cellular proteins that bind to wild-type but not mutant p53

Abstract: p53 is a tumor-suppressor protein that can activate and repress transcription. Using the yeast two-hybrid system, we identified two previously uncharacterized human proteins, designated 53BP1 and 53BP2, that bind to p53. 53BP1 shows no significant homology to proteins in available databases, whereas 53BP2 contains two adjacent ankyrin repeats and a Src homology 3 domain. In vitro binding analyses indicate that both of these proteins bind to the central domain of p53 (residues 80-320) required for site-specific DNA binding. Consistent with this finding, p53 cannot bind simultaneously to 53BP1 or 53BP2 and to a DNA fragment containing a consensus p53 binding site. Unlike other cellular proteins whose binding to p53 has been characterized, both 53BP1 and 53BP2 bind to the wild-type but not to two mutant p53 proteins identified in human tumors, suggesting that binding is dependent on p53 conformation. The characteristics of these interactions argue that 53BP1 and 53BP2 are involved in some aspect of p53-mediated tumor suppression.

Dynamics of synaptic vesicle fusion and membrane retrieval in synaptic terminals

Abstract: Communication among neurons occurs at specialized synaptic junctions, where neurotransmitter is released via calcium-dependent exocytosis from the synaptic terminal of the presynaptic cell onto the postsynaptic target neuron. Here we exploit the unique properties of giant synaptic terminals of bipolar neurons from goldfish retina to establish the kinetics and calcium-dependence of exocytosis, and the characteristics of membrane retrieval following secretion in presynaptic terminals. Simultaneous patch-clamp, calcium-indicator dye and time-resolved capacitance measurements reveal that activation of calcium current drives secretion at a rapid rate of about 10,000 vesicles per s and the calcium level necessary to drive secretion is locally greater than 50 microM. Two components of membrane retrieval were observed following secretory stimulation. After strong stimulation, capacitance returned to rest with a time constant of about 30 s, but after weaker stimuli recovery was much faster, with a time constant of about 2 s. Secretion in a vertebrate central nervous system neuron was thus found to differ substantially from that in other secretory cells in its rapid rate of vesicle fusion, requirement for high levels of intracellular calcium, and the high speed and completeness of membrane retrieval. These distinctive features reflect the specialization of neuronal synaptic terminals for rapid and focally directed release of neurotransmitter.

The toxicokinetics and metabolism of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and their relevance for toxicity.

Abstract: This article reviews the present state of the art regarding the toxicokinetics and metabolism of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). The absorption, body distribution, and metabolism can vary greatly between species and also may depend on the congener and dose. In biota, the 2,3,7,8-substituted PCDDs and PCDFs are almost exclusively retained in all tissue types, preferably liver and fat. This selective tissue retention and bioaccumulation are caused by a reduced rate of biotransformation and subsequent elimination of congeners with chlorine substitution at the 2,3,7, and 8 positions. 2,3,7,8-Substituted PCDDs and PCDFs also have the greatest toxic and biological activity and affinity for the cytosolic arylhydrocarbon (Ah)-receptor protein. The parent compound is the causal agent for Ah-receptor-mediated toxic and biological effects, with metabolism and subsequent elimination of 2,3,7,8- substituted congeners representing a detoxification process. Congener-specific affinity of PCDDs and PCDFs for the Ah-receptor, the genetic events following receptor binding, and toxicokinetics are factors that contribute to the relative in vivo potency of an individual PCDD or PCDF in a given species. Limited human data indicate that marked species differences exist in the toxicokinetics of these compounds. Thus, human risk assessment for PCDDs and PCDFs needs to consider species-, congener-, and dose-specific toxicokinetic data. In addition, exposure to complex mixtures, including PCBs, has the potential to alter the toxicokinetics of individual compounds. These alterations in toxicokinetics may be involved in some of the nonadditive toxic or biological effects that are observed after exposure to mixtures of PCDDs or PCDFs with PCBs.

Free Radical Scavenging and Antioxidant Activity of Plant Flavonoids

Abstract: The occurrence of reactive oxygen species (ROS), termed as prooxidants, is a characteristic of normal aerobic organisms. The term “reactive oxygen species” collectively denotes oxygen-centered radicals such as superoxide (O2·-)and hydroxyl (·OH), as well as nonradical species derived from oxygen, such as hydrogen peroxide (H2O2), singlet oxygen (1ΔgO2) and hypochlorous acid (HOC1). Radical reactions are central to the maintenance of homeostasis in biological systems. Radical species perform a cardinal role in many physiological processes such as cytochrome P450-mediated oxidative transformation reactions, a plethora of enzymic oxidation reactions, oxidative phosphorylation, regulation of the tone of smooth muscle, and killing of microorganisms.1–3 Excessive generation of free radicals can have deleterious biological consequences.4–6 Organisms are equipped with an armamentarium of defense systems, termed antioxidants in order to safeguard them against the onslaught of ROS.1–3,7 When the generation of prooxidants overwhelms the capacity of antioxidant defense systems oxidative stress ensues. This can cause tissue damage leading to pathophysiological events. ROS play a pivotal role in the action of numerous foreign compounds (xenobiotics). Their increased production seems to accompany most forms of tissue injury.4,5 Whether sustained and increased production of ROS is a primary event in human disease progression or a secondary consequence of tissue injury has been discussed.5,6 Whatever may be the case, the formation of free radicals has been implicated in a multitude of disease states ranging from inflammatory/immune injury to myocardial infarction and cancer.

Polymeric fullerene chains in RbC60 and KC60

Abstract: NEARLY all of the molecular crystals containing C60, formed at ambient pressure1,2 have inter-fullerene separations of the order of 10 A — the expected distance based on the molecular van der Waals radii. The sole exceptions are the room-temperature phases of AC60 (where A denotes K, Rb or Cs), which are formed by reversible solid-state transformation from high-temperature (>150 °C) phases3. These phases have lattice parameters about 9% shorter in one direction, and in addition RbC60 has magnetic properties suggestive of a one-dimensional metal4. We suggested in ref. 4 that this short distance may be due to covalent bonding between neighbouring C60 molecules. Here we provide direct evidence for such bonding from powder X-ray diffraction studies of RbC60 and KC60 . The linkage is through a [2+2] cycloaddition, which has been hypothesized to take place during photopolymerization of solid C60 (ref. 5), and which has also been proposed6 for RbC60. Such inter-fullerene linkages are calculated7,8 to be the preferred mode of dimerization of C60. The AC60 phases thus provide an example of a thermal phase transition driven by the reversible formation and breaking of covalent bonds.

Clonal Divergence in Escherichia coli as a Result of Recombination, Not Mutation

Abstract: Nucleotide sequence analysis was performed on 12 natural isolates of Escherichia coli in four loci located in close proximity on the chromosome. A comparison of gene genealogies indicated that three recombination events have occurred in a subset of the strains (ECOR group A) in the time since their divergence from a common ancestor, while during the same time, no mutational divergence has occurred. The common ancestor of this subset existed no more than 2400 years ago, and recombination was shown to occur at a rate of 5.0 x 10(-9) changes per nucleotide per generation--50-fold higher than the mutation rate. Thus, recombination has been the dominant force driving the clonal divergence of the ECOR group A strains and must be considered a significant factor in structuring E. coli populations.

Isolation, cDNA cloning, and overexpression of a 33-kD cell surface glycoprotein that binds to the globular "heads" of C1q.

Abstract: This work describes the functional characterization, cDNA cloning, and expression of a novel cell surface protein. This protein designated gC1q-R, was first isolated from Raji cells and was found to bind to the globular "heads" of C1q molecules, at physiological ionic strength, and also to inhibit complement-mediated lysis of sheep erythrocytes by human serum. The NH2-terminal amino acid sequence of the first 24 residues of the C1q-binding protein was determined and this information allowed the synthesis of two degenerate polymerase chain reaction primers for use in the preparation of a probe in the screening of a B cell cDNA library. The cDNA isolated, using this probe, was found to encode a pre-pro protein of 282 residues. The NH2 terminus of the protein isolated from Raji cells started at residue 74 of the predicted pre-pro sequence. The cDNA sequence shows that the purified protein has three potential N-glycosylation residues and is a highly charged, acidic molecule. Hence, its binding to C1q may be primarily but not exclusively due to ionic interactions. The "mature" protein, corresponding to amino acid residues 74-282 of the predicted pre-pro sequence, was overexpressed in Escherichia coli and was purified to homogeneity. This recombinant protein was also able to inhibit the complement-mediated lysis of sheep erythrocytes by human serum and was shown to be a tetramer by gel filtration in nondissociating conditions. Northern blot and RT-PCR studies showed that the C1q-binding protein is expressed at high levels in Raji and Daudi cell lines, at moderate levels in U937, Molt-4, and HepG2 cell lines, and at a very low level in the HL60 cell line. However, it is not expressed in the K562 cell line. Comparison of gC1q-R NH2-terminal sequence with that of the receptor for the collagen-like domain of C1q (cC1q-R) showed no similarity. Furthermore, antibodies to gC1q-R or an 18-amino acid residue-long NH2-terminal synthetic gC1q-R peptide did not cross-react with antibodies to cC1q-R. Anti-gC1q-R immunoblotted a 33-kD Raji cell membrane protein, whereas anti cC1q-R recognized a molecule of approximately 60 kD. The NH2-terminal sequence of gC1g-R appears to be displayed extracellularly since anti-gC1g-R peptide reacted with surface molecules on lymphocytes, polymorphonuclear leukocytes, and platelets, as assessed by flow cytometric and confocal laser scanning microscopic analyses.(ABSTRACT TRUNCATED AT 400 WORDS)