bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantification of the fractal nature of mycelial aggregation in Aspergillus niger submerged cultures
Authors: Papagianni Maria 
Published: February 2006

Abstract

Background
Fractal geometry estimates have proven useful in studying the growth strategies of fungi in response to different environments on soil or on agar substrates, but their use in mycelia grown submerged is still rare. In the present study, the effects of certain important fermentation parameters, such as the spore inoculum level, phosphate and manganese concentrations in the medium, on mycelial morphology of the citric acid producer Aspergillus niger were determined by fractal geometry. The value of employing fractal geometry to describe mycelial structures was examined in comparison with information from other descriptors including classic morphological parameters derived from image analysis.

Results
Fractal analysis of distinct morphological forms produced by fermentation conditions that influence fungal morphology and acid production, showed that the two fractal dimensions D
BS (box surface dimension) and D
BM (box mass dimension) are very sensitive indexes, capable of describing morphological differences. The two box-counting methods applied (one applied to the whole mass of the mycelial particles and the other applied to their surface only) enabled evaluation of fractal dimensions for mycelial particles in this analysis in the region of D
BS = 1.20–1.70 and D
BM = 1.20–2.70. The global structure of sufficiently branched mycelia was described by a single fractal dimension D, which did not exceed 1.30. Such simple structures are true mass fractals (D
BS = D
BM = D) and they could be young mycelia or dispersed forms of growth produced by very dense spore inocula (108–109 spores/ml) or by addition of manganese in the medium. Mycelial clumps and pellets were effectively discriminated by fractal analysis. Fractal dimension values were plotted together with classic morphological parameters derived from image analysis for comparisons. Their sensitivity to treatment was analogous to the sensitivity of classic morphological parameters suggesting that they could be equally used as morphological descriptors.

Conclusion
Starting from a spore, the mycelium develops as a mass fractal and, depending on culture conditions, it either turns to a surface fractal or remains a mass fractal. Since fractal dimensions give a measure of the degree of complexity and the mass filling properties of an object, it may be possible that a large number of morphological parameters which contribute to the overall complexity of the particles, could be replaced by these indexes effectively.
Canine parvovirus-like particles, a novel nanomaterial for tumor targeting
Authors: Singh Pratik , Destito Giuseppe , Schneemann Anette , Manchester Marianne 
Published: February 2006

Abstract
Specific targeting of tumor cells is an important goal for the design of nanotherapeutics for the treatment of cancer. Recently, viruses have been explored as nano-containers for specific targeting applications, however these systems typically require modification of the virus surface using chemical or genetic means to achieve tumor-specific delivery. Interestingly, there exists a subset of viruses with natural affinity for receptors on tumor cells that could be exploited for nanotechnology applications. For example, the canine parvovirus (CPV) utilizes transferrin receptors (TfRs) for binding and cell entry into canine as well as human cells. TfRs are over-expressed by a variety of tumor cells and are widely being investigated for tumor-targeted drug delivery. We explored whether the natural tropism of CPV to TfRs could be harnessed for targeting tumor cells. Towards this goal, CPV virus-like particles (VLPs) produced by expression of the CPV-VP2 capsid protein in a baculovirus expression system were examined for attachment of small molecules and delivery to tumor cells. Structural modeling suggested that six lysines per VP2 subunit are presumably addressable for bioconjugation on the CPV capsid exterior. Between 45 and 100 of the possible 360 lysines/particle could be routinely derivatized with dye molecules depending on the conjugation conditions. Dye conjugation also demonstrated that the CPV-VLPs could withstand conditions for chemical modification on lysines. Attachment of fluorescent dyes neither impaired binding to the TfRs nor affected internalization of the 26 nm-sized VLPs into several human tumor cell lines. CPV-VLPs therefore exhibit highly favorable characteristics for development as a novel nanomaterial for tumor targeting.
Absence of seroreversion in 80 HAART-treated HIV-1 seropositive patients with at least five-years undetectable plasma HIV-1 viral load
Authors: Cornelissen Marion , Jurriaans Suzanne , Prins Jan M , Bakker Margreet , van der Kuyl Antoinette C 
Published: February 2006

Abstract
Partial or complete seroreversion for HIV-1, or incomplete antibody evolution are relatively rare events that have so far only been described in patients treated with HAART early after virus infection. Whether seroreversion is seen in patients treated effectively with HAART years after their acute infection has not been investigated so far. Therefore we have investigated anti-HIV antibody levels in 80 patients treated with HAART during chronic HIV-1 infection, who had an undetectable HIV-1 plasma viral load for at least five years. In none of the patients we observed seroreversion, and there was also no significant decrease or increase in antibody levels in this group of patients. So, successful HAART treatment during chronic HIV-1 infection does not induce seroreversion.
Thyroid status influence on adiponectin, acylation stimulating protein (ASP) and complement C3 in hyperthyroid and hypothyroid subjects
Authors: Yu Haiying , Yang Yan , Zhang Muxun , Lu Huiling , Zhang Jianhua , Wang Hongwei , Cianflone Katherine 
Published: February 2006

Abstract

Background
Thyroid abnormalities (hyperthyroid and hypothyroid) are accompanied by changes in intermediary metabolism including alterations in body weight, insulin resistance and lipid profile. The aims of this study were to examine plasma ASP, its precursor C3 and adiponectin in hyperthyroid and hypothyroid subjects as compared to controls.

Methods
A total of 99 subjects were recruited from endocrinology/out-patient clinics: 46 hyperthyroid subjects, 23 hypothyroid subjects and 30 control subjects. Subjects were evaluated for FT4, FT3, TSH, glucose, insulin, complete lipid profile and the adipokines: adiponectin, acylation stimulating protein (ASP) and complement C3.

Results
Hyperthyroidism was associated with a 95% increase in adiponectin (p = 0.0002), a 47% decrease in C3 (p < 0.0001), no change in ASP and increased ASP/C3 ratio (p = 0.0012). Hypothyroidism was associated with a 31% increase in ASP (p = 0.008). Adiponectin and C3 correlated with FT3 (r = 0.383, p = 0.004 and r = -0.277, p = 0.007, respectively) and FT4 (r = 0.464, p = 0.003 and r = -0.225, p = 0.03, respectively). ASP correlated with TSH (r = 0.202, p = 0.04). Adiponectin did not correlate with either ASP or C3, only ASP and C3 correlated (r = -0.197, p = 0.05). Adiponectin was negatively correlated with BMI, total cholesterol and plasma triglyceride, while C3 was positively correlated with BMI and total cholesterol. Surprisingly, adiponectin was positively correlated with insulin (r = 0.293, p = 0.02) and HOMA-IR (r = 0.373, p = 0.003) while C3 was negatively correlated with glucose (r = -0.242, p = 0.022, insulin (r = -0.184, p = 0.05) and HOMA-IR.

Conclusion
These changes suggest that thyroid disease may be accompanied by changes in adipokines, which may contribute to the phenotype expressed.
A Model of Plausibility
Authors: Connell Louise , Keane Mark T. 
Published: February 2006

AbstractPlausibility has been implicated as playing a critical role in many cognitive phenomena from comprehension to problem solving. Yet, across cognitive science, plausibility is usually treated as an operationalized variable or metric rather than being explained or studied in itself. This article describes a new cognitive model of plausibility, the Plausibility Analysis Model (PAM), which is aimed at modeling human plausibility judgment. This model uses commonsense knowledge of concept‐coherence to determine the degree of plausibility of a target scenario. In essence, a highly plausible scenario is one that fits prior knowledge well: with many different sources of corroboration, without complexity of explanation, and with minimal conjecture. A detailed simulation of empirical plausibility findings is reported, which shows a close correspondence between the model and human judgments. In addition, a sensitivity analysis demonstrates that PAM is robust in its operations.
Differential Response of Progesterone Receptor Isoforms in Hormone-Dependent and -Independent Facilitation of Female Sexual Receptivity
Authors: Mani Shaila K. , Reyna Andrea M. , Chen Jian Zhong , Mulac-Jericevic Biserka , Conneely Orla M. 
Published: February 2006

AbstractNeurobehavioral effects of progesterone are mediated primarily by its interaction with neural progesterone receptors (PRs), expressed as PR-A and PR-B protein isoforms. Whereas the expression of two isoforms in the neural tissues is suggestive of their selective cellular responses and modulation of distinct subsets of PR-induced target genes, the role of individual isoforms in brain and behavior is unknown. We have previously demonstrated a critical role for PRs as transcriptional mediators of progesterone (ligand-dependent), and dopamine (ligand-independent)-facilitated female reproductive behavior in female mice lacking both the isoforms of PR. To further elucidate the selective contribution of the individual PR isoforms in female sexual receptive behavior, we used the recently generated PR-A and PR-B isoform-specific null mutant mice. We present evidence for differential responses of each isoform to progesterone and dopamine agonist, SKF 81297 (SKF), and demonstrate a key role for PR-A isoform in both hormone-dependent and -independent facilitation of sexual receptive behavior. Interestingly, whereas both the isoforms were essential for SKF-facilitated sexual behavior, PR-A appeared to play a more important role in the 8-bromo-cAMP-facilitated lordosis response, raising the possibility of distinct intracellular signaling pathways mediating the responses. Finally, we also demonstrate that antiprogestin, RU38486, was an effective inhibitor of PR-A-mediated, progesterone-dependent, but not SKF or 8-bromo-cAMP-dependent sexual receptivity. The data reveal the selective contributions of individual isoforms to the signaling pathways mediating female reproductive behavior.
Ab initio crystal structure determination of Bi6Rh12O29 from powder diffraction data
Authors: Stowasser Frank , Renkenberger Christof 
Published: February 2006

Abstract
The complex crystal structure of Bi6Rh12O29 was determined from laboratory X-ray powder diffraction data with the software package TOPAS® [1]. The crystal symmetry is monoclinic (space group C2/m, Z = 4) and the unit cell parameters are a = 19.8510(1) Å, b = 12.24424(6) Å, c = 9.52367(5) Å and β = 97.2890(4)°. The structure is stable at normal pressure and room temperature. There are 4 Bi, 9 Rh and 18 O in the asymmetric unit and totally 188 atoms in the complete unit cell. Rhodium is coordinated by oxygen in slightly distorted edge sharing octahedra which build up crossing sheets both parallel (100) with a distance of d
100/2 and parallel (001) with a distance of d
001. The remaining channels along b contain the bismuth ions in irregular 6- and 8-fold coordination. Because of a small excess of oxygen in the formula – with respect to an expected amount of oxygen indicated by trivalent Bi and also trivalent Rh — the oxidation state of rhodium adjusts to a formal +3.33.
Second-Best Climate Agreements and Technology Policy
Authors: Golombek Rolf , Hoel Michael 
Published: February 2006

Abstract
We study second-best climate agreements in the presence of technology spillovers within and across countries, where the technology externalities within each country are corrected through a domestic subsidy of R&D investments. We compare the properties of two types of international climate agreements when the inter-country externalities from R&D are not regulated through the climate agreement. With an international agreement on emission quotas, the equilibrium R&D subsidy is lower than the socially optimal subsidy. The equilibrium subsidy is even lower if the climate agreement instead dictates that a common carbon tax should be imposed in all countries. Under a quota agreement, total quotas should be set low enough for the price of carbon to exceed the Pigovian level, whereas the opposite may be true under a tax agreement. We also show that social costs are higher under a second-best tax agreement than under a second-best quota agreement.
Competitive Work Environments and Social Preferences: Field Experimental Evidence from a Japanese Fishing Community
Authors: Carpenter Jeffrey P , Seki Erika 
Published: February 2006

Abstract
Models of job tournaments and competitive workplaces more generally predict that while individual effort may increase as competition intensifies between workers, the incentive for workers to cooperate with each other diminishes. We report on a field experiment conducted with workers from a fishing community in Toyama Bay, Japan. Our participants are employed in three different aspects of fishing. The first group are fishermen, the second group are fish wholesalers (or traders), and the third group are staff at the local fishing coop. Although our participants have much in common (e.g., their common relationship to the local fishery and the fact that they all live in the same community), we argue that they are exposed to different amounts of competition on-the-job and that these differences explain differences in cooperation in our experiment. Specifically, fishermen and traders, who interact in more competitive environments are significantly less cooperative than the coop staff who face little competition on the job. Further, after accounting for the possibility of personality-based selection, perceptions of competition faced on-the-job and the treatment effect of job incentives explain these differences in cooperation to a large extent.
The Firm's Cost of Capital, Its Effective Marginal Tax Rate, and the Value of the Government's Tax Claim
Authors: Rao Ramesh K. S. , Stevens Eric C 
Published: February 2006

Abstract
This paper develops a theory of the firm's weighted average cost of capital (WACC) and the marginal tax rate with risky debt and potentially redundant depreciation and interest tax shields. The tax shields' risks, the firms borrowing interest rate and its marginal tax rate are intertwined, and they must therefore be determined simultaneously. We capture these interdependencies by determining the borrowing interest rate endogenously, using the single-factor approximate arbitrage pricing theory. This research strategy: a) yields the correct discount rate for valuing the tax shields and shows how better WACC and marginal tax rate estimates can be generated, b) identifies the determinants of the firm's debt capacity in terms of asset characteristics and exogenous economic variables and c) specifies, numerically, how policy variables (corporate tax rate, tax rules, the risk-free rate) affect the market values of claims on the firm's output that are both private (debt, equity) and public (the tax claim).
Do Plants Overcomply with Water Pollution Regulations? The Role of Discharge Variability
Authors: Bandyopadhyay Sushenjit , Horowitz John 
Published: February 2006

Abstract
This paper uses previously unexploited data to examine polluters' compliance with point-source water pollution regulations, a line of inquiry motivated by widespread apparent overcompliance. We use a nationwide panel of monthly plant-level effluent concentrations from 1991-1999. These monthly data allow us to observe month-to-month variability in discharges and therefore to test hypotheses not previously examined.We find that plants that have higher discharge variability have lower median discharges. This is strong evidence for the purported "safety margin" effect. This result then implies that average discharges, a common measure of polluter behavior, are not an accurate indicator of polluter behavior.In response, we construct a plant-specific implied probability of a violation that accounts for discharge variability. We show that plants in richer communities have lower violation probabilities. We further argue that plants are indeed overcomplying with the regulations even when accounting for the safety margin effect.
Application of Experimental Stressors in Laboratory Rodents
Authors: Heinrichs Stephen C. , Koob George F. 
Published: February 2006

AbstractThis unit presents eight separate stressor protocols for laboratory rodents. Stress induction is a critical element in the study of neural and neuroendocrine mechanisms involved in establishing and maintaining a state of stress. The first four procedures, immobilization, footshock, swimming, and noise, involve acute exposure to noxious stimuli. The next three procedures, social isolation, resident/intruder aggression, and maternal deprivation, induce social disruption by withdrawal from a group housing condition, attack within the unfamiliar territory of a dominant male, or segregation of a preweanling pup from its mother, respectively. The final procedure, sleep deprivation, involves passive denial of the opportunity to sleep. Support protocols are provided to address the need for environmental acclimation and calming procedures prior to any stress‐related studies (including, for rats, handling of the animals as a calming measure) and to detail a simple method of quantifying the response to a given stressor by direct measurement of levels of the stress hormones adrenocorticotropic hormone (ACTH) and corticosterone.
Overview of Methods for Assessing the Mouse Auditory System
Authors: Willott James F. 
Published: February 2006

AbstractThe three general approaches for assessing the mouse auditory system presented in UNITS here–here are complementary, but differ in the time required for testing as well as the goals of the tests: the auditory brainstem response (ABR; UNIT here), distortion product otoacoustic emissions (DPOAE; UNIT here), and lick suppression behavioral test (UNIT here). Various issues that need to be addressed in the testing of mouse hearing are discussed in this overview, including accurate nomenclature of the strain and/or mutations, environmental versus genetic influences, selection of frequencies to be tested, and appropriate animal care and use.
Behavioral Assessment of Hearing in Mice—Conditioned Suppression
Authors: Heffner Henry E. , Koay Gimseong , Heffner Rickye S. 
Published: February 2006

AbstractThe method of conditioned suppression described in this unit involves training a thirsty mouse to make steady contact with a waterspout in order to receive a slow, but steady trickle of water and then pairing a sound with mild electric shock delivered through the spout. The mouse quickly learns to avoid the shock by breaking contact with the spout whenever it detects the sound. This suppression of drinking is then used to indicate that the animal detected the sound. Because it is a cognitively simple procedure, conditioned suppression can be used to determine the ability of brain‐damaged and genetically altered as well as normal animals to detect and discriminate sounds.
The Detection of MAPK Signaling
Authors: Shaul Yoav , Seger Rony 
Published: February 2006

AbstractMitogen‐activated protein kinase (MAPK) cascades are central pathways that participate in the intracellular transmission of extracellular signals. Each of the MAPK signaling cascades seems to consist of three to five tiers of protein kinases that sequentially activate each other by phosphorylation. Since the majority of MAPK cascade components are kinases, the methods used to detect their activation involve determining phosphorylation state and protein kinase activities. The primary method describes the use of immunoblotting with specific anti‐phospho antibody to detect activation of MAPK components. Alternative methods described are immunoprecipitation of desired protein kinases followed by phosphorylation of specific substrates and the use of an in‐gel kinase assay. These methods have proven useful in the study of the MAPK signaling cascades.
Minimizing Variation Due to Genotype and Environment
Authors: Argmann Carmen A. , Auwerx Johan 
Published: February 2006

AbstractMouse models are increasingly popular tools to study and characterize the molecular and physiological bases for human diseases. Due to the readily available genetic tools to construct mouse models of complex diseases, the flow of efficient and vigilant mouse phenotyping has now become the bottleneck in mouse functional genomics. This unit addresses the importance of minimizing and defining confounding genetic and environmental sources of variability.
Nuclear DNA Content Analysis of Plant Seeds by Flow Cytometry
Authors: Sliwinska Elwira 
Published: February 2006

AbstractProcedures describing the utilization of seeds or their parts for flow cytometric determination of plant ploidy and endopolyploidy, genome size, and cell cycle activity are presented. The methods have been developed for a single‐fluorescence‐parameter flow cytometer, equipped with light sources for 488‐nm and UV‐light illumination. The procedures presented in this unit utilize the two most widely used fluorochromes for plant DNA content analysis, propidium iodide (PI) and 4′,6‐diamidino‐2‐phenylindole (DAPI). These methods provide an alternative to estimation of DNA content based on the fluorescence of DNA in cell nuclei isolated from plant leaves. In some instances seeds are more suitable for analysis than leaves, e.g., when plant material must be transported for a long distances or stored for prolonged periods before flow cytometric analysis, or when leaves contain fluorochrome‐staining inhibitors. In addition, flow cytometric determination of nuclear replication stages in seeds gives information about their physiological status (e.g., maturity, advancement of germination), which is valuable to seed producers and technologists.
Characterization of Nuclear Receptor Ligands by Multiplexed Peptide Interactions
Authors: Iannone Marie A. 
Published: February 2006

AbstractThis unit describes a method to evaluate the effect that small molecules have on the binding interactions of a nuclear receptor protein with a series of peptides. The multiplexed microsphere‐based system employs peptide‐coupled microsphere populations that are fluorescently unique and thereby identifiable by flow cytometric analysis. Up to 100 different peptide–nuclear receptor interactions may be analyzed in a single well of a 96‐well microtiter plate. This approach allows rapid and sensitive characterization of nuclear receptor ligands based on nuclear receptor protein–peptide interaction profiles. Since nuclear receptor binding interactions are dynamically related to protein conformation, the approach allows rapid evaluation of nuclear receptor ligands that may impart unique protein structure. The no‐wash format and the high surface density of the microsphere‐coupled interaction partner offer a moderately high‐throughput system to examine low‐ to high‐affinity interactions with excellent sensitivity. This approach, although described for nuclear receptors, may also be applied to other types of molecular interactions.