bluuebunny/crossref_metadata_2025_split huggingface dataset:
UNDERSTANDING THE GREY ENTREPRENEUR
Authors: WEBER PAULL , SCHAPER MICHAEL 
Published: October 2004

Demographic trends in the developed world indicate that older entrepreneurs will play an increasingly important part of economic activity as populations age, yet this cohort has been largely ignored in entrepreneurship research. This paper provides an overview of current research about the so-called "grey entrepreneur" (also known as senior, older, third age or elderly entrepreneurs), drawing on research from a number of nations. The extant literature indicates that a majority of older entrepreneurs are male, although the number of older female entrepreneurs is increasing; they are also less likely to possess formal educational qualifications than younger entrepreneurs. Some of the advantages that such entrepreneurs possess include greater levels of technical, industrial and management experience; superior personal networks; and a stronger financial asset base. Some of the disadvantages or potential barriers faced by older entrepreneurs can include lower levels of health, energy and productivity; ageism; and the value that his or her society places on active ("productive") ageing. Numerous issues still remain to be investigated in this field of research. These include the differences between younger and older entrepreneurs; their motives and success criteria; the impact of financial, knowledge and other resources on venturing behaviour; the role of government policies in fostering or hampering individual enterprise; and the significance of cultural differences amongst older entrepreneurs. Research in this field is currently also hampered by a multiplicity of terms and definitions, a lack of age-related data about different entrepreneurial cohorts, and the problems inherent in operationalising the concept of the "grey entrepreneur."
CRYPTANALYSIS OF AN IMPLEMENTATION SCHEME OF THE TAMED TRANSFORMATION METHOD CRYPTOSYSTEM
Authors: DING JINTAI , HODGES TIMOTHY 
Published: October 2004

A Tamed Transformation Method (TTM) cryptosystem was proposed by T. T. Moh in 1999. We describe how the first implementation scheme of the TTM system can be defeated. The computational complexity of our attack is 233 computations on the finite field with 28 elements. The cipher of the TTM systems are degree 2 polynomial maps derived from composition of invertible maps of either total degree 2 or linear maps which can be easily calculated and can be easily inverted. To ensure the system to be of degree two, the key construction of the implementation schemes of the TTM systems is a multivariable polynomial Q8(x1,…,xn) and a set of linearly independent quadratic polynomials qi(x1,…,xm), i=1,…,n such that Q8(q1,…,qn) is again a degree 2 polynomials of x1,…,xm. In this paper, we study the first implementation scheme of the TTM systems [6]. We discovered that in this implementation scheme the specific polynomial Q8 can be decomposed further into a factorization in terms of composition. By taking powers of the equality satisfied by the new composition factors, we can actually derive a set of equations, that can produce linear equations satisfied by the plaintext. These linear equations lead us to find a way to defeat this implementation scheme.
TORSION-FREENESS FOR RINGS WITH ZERO-DIVISORS
Authors: DAUNS JOHN , FUCHS LASZLO 
Published: October 2004

A right R-module MR over any ring R with 1 is called torsion-free if it satisfies the equality [Formula: see text] for every r∈R. An equivalent definition was used by Hattori [11]. We establish various properties of this concept, and investigate rings (called torsion-free rings) all of whose right ideals are torsion-free. In a torsion-free ring, the right annihilators of elements are always idempotent flat right ideals. The right p.p. rings are characterized as torsion-free rings in which the right annihilators of elements are finitely generated. An example shows that torsion-freeness ness is not a Morita invariant. Several ring and module properties are proved, showing that, in several respects, torsion-freeness ness behaves like flatness. We exhibit examples to point out that the concept of torsion-freeness ness discussed here is different from other notions.
Chemotherapieassoziierte Enterokolitis – Eine seltene, aber potenziell letal verlaufende Nebenwirkung bei der adjuvanten Behandlung des Mammakarzinoms
Authors: Janni J.W. , Klanner E. , Rack B. , Sommer H. , Friese K. 
Published: October 2004

<i>Anamnese:</i> Eine 60-jährige Patientin wurde wegen eines Mammakarzinoms im TNM-Stadium pT1a (m), pN2a (8/12), G2, pM0 brusterhaltend operiert. Im Anschluss erhielt sie 4 Zyklen Epirubicin/ Cyclophosphamid (90/600 mg/m<sup>2</sup>), gefolgt von 2 Zyklen Docetaxel (100 mg/m<sup>2</sup>). Vier Tage nach Erhalt des zweiten Zyklus Docetaxel stellte sich die Patientin mit Bauchschmerzen, Nausea, Emesis und Obstipation bestehend seit 3 Tagen vor. <i>Befunde:</i> Die körperliche Untersuchung zeigte ein geblähtes Abdomen, das Fehlen von Darmgeräuschen und eine Druckdolenz im linken Unterbauch. Im Labor fiel eine Granulozytopenie mit NCI Grad III und eine CRP-Erhöhung von 7,7 mg/dl auf. <i>Diagnose:</i> Als Hauptdiagnose wurde der Verdacht auf eine chemotherapieassoziierte Enterokolitis mit Zeichen eines paralytischen Ileus gestellt, der sich computertomographisch und per laparatomiam bestätigte. <i>Therapie und Verlauf:</i> Die Erstversorgung erfolgte mit einer Magensonde, Infusionstherapie, Breitbandantibiose und G-CSF. Im weiteren Verlauf wurde bei sich verschlechterndem Allgemeinzustand und Verdacht auf intraabdominelles Kompartmentsyndrom fünfmal eine Explorativlaparotomie mit abdomineller Lavage durchgeführt. Nach vorübergehender Besserung verstarb die Patientin 8 Wochen nach Aufnahme im protrahierten Multiorganversagen. <i>Fazit:</i> Bei der chemotherapieassoziierten Enterokolitis handelt es sich um eine seltene, aber potenziell letale Nebenwirkung einer zytostatischen Therapie. Gastrointestinalen Symptomen sollte deshalb eine grosse Aufmerksamkeit geschenkt werden, um durch eine rechtzeitige Therapieintervention das Mortalitätsrisiko zu minimieren.
Vasoactive Intestinal Peptide Can Modulate Immune and Endocrine Responses during Lipopolysaccharide-Induced Acute Inflammation
Authors: Bik Wojciech , Wolinska-Witort Ewa , Chmielowska Magdalena , Baranowska-Bik Agnieszka , Rusiecka-Kuczalek Elzbieta , Baranowska Boguslawa 
Published: October 2004

<i>Objectives:</i> In many studies, it has been reported that vasoactive intestinal peptide (VIP) may play an important role in modulation of the immunological response. VIP can be produced by immunological cells, and also the receptors for this neuropeptide are present in many of these cells. The aim of our study was to estimate the effects of the administration of exogenous VIP on serum concentrations of proinflammatory cytokines [interleukin (IL)-6 and tumor necrosis factor (TNF)-α] and an anti-inflammatory cytokine (IL-10) during lipopolysaccharide (LPS)-induced acute inflammation. We also estimated the influence of VIP on pituitary [FSH, LH, TSH and prolactin (PRL)], thyroid (T3 and T4), adrenal (corticosterone) and gonadal (testosterone) hormones in response to LPS-induced acute inflammation. <i>Methods:</i> Male Wistar-Kyoto rats were divided into four groups, which received, respectively, placebo (0.9% NaCl), LPS, VIP and VIP with LPS. The TNF-α and IL-6 serum concentrations were measured after 2 h from the time of the administration of the agents, IL-10 was measured after 4 h, and the pituitary, thyroid, adrenal and gonadal hormone concentrations were measured after 2 and 4 h. Cytokine concentrations were estimated using ELISA tests, and hormone concentrations were measured using RIA tests. <i>Results:</i> In our experiments, LPS administration dramatically increased serum proinflammatory cytokine concentrations (TNF-α and IL-6) after 2 h and the anti-inflammatory cytokine (IL-10) after 4 h, as well as increasing the serum corticosterone concentration (after 2 and 4 h) and LH (after 2 h). LPS application decreased serum concentrations of T3 and TSH (both after 2 h), testosterone (after 2 and 4 h), FSH after 4 h and PRL after 4 h. VIP administration decreased the serum IL-10 concentration after 4 h and T3 concentration after 2 h and increased serum concentrations of FSH and corticosterone after 4 h. VIP administrated simultaneously with LPS decreased the LPS-induced increase in IL-6 and corticosterone concentrations (consecutively after 2 and 4 h). VIP also enhanced LPS-induced thyroid hormone (T3 and T4) suppression after 4 h and testosterone suppression after 4 h. <i>Conclusion:</i> We conclude that VIP can modulate not only immune responses but also hormonal responses during acute inflammation.
Prognostic Relevance of Altered pRb and p53 Protein Expression in Surgically Treated Non-Small Cell Lung Cancer Patients
Authors: Dworakowska Dorota , Jassem Ewa , Jassem Jacek , Wiedorn Klaus Hermann , Boltze Carsten , Karmoliński Andrzej , Dworakowski Rafał , Skokowski Jan , Jaśkiewicz Kazimierz , Bosse Alexander , Częstochowska Eugenia 
Published: October 2004

<i>Objective:</i> The prognostic value of pRb and p53 altered expression in non-small cell lung cancer (NSCLC) remains debatable. We assessed the occurrence of altered pRb and p53 protein expression, and the prognostic value of these assays considered as separate and combined variables in operable NSCLC. The study group included 195 NSCLC consecutive patients from one institution who underwent curative pulmonary resection between 1994 and 1999. <i>Methods:</i> Expression of pRb and p53 was assessed immunohistochemically with the use of monoclonal antibodies (LM95.1 and Pab 1801, Oncogene Science, respectively). <i>Results:</i> A lack of pRb and abnormal p53 protein expression were found in 57 (29%) and 92 samples (47%), respectively, whereas both abnormalities (pRb–/p53+) occurred in 24 samples (12%). There was no relationship between altered pRb/p53 expression and major clinico-pathological characteristics, neither was there a significant difference in disease-free and overall survival between particular groups of patients with tumors carrying four possible pRb/p53 phenotypes. In uni- and multivariate analysis, the only variable associated with shortened disease-free and overall survival was stage of disease (p < 0.001) and degree of tumor differentiation (p = 0.005). <i>Conclusion:</i> These results suggest that altered pRb and p53 expression does not provide prognostic information in operable NSCLC patients.
Brain but Not Spinal NR2B Receptor Is Responsible for the Anti-Allodynic Effect of an NR2B Subunit-Selective Antagonist CP-101,606 in a Rat Chronic Constriction Injury Model
Authors: Nakazato Etsuko , Kato Aki , Watanabe Shuzo 
Published: October 2004

In order to examine the site of action of an NR2B subtype-selective NMDA antagonist CP-101,606, we investigated its analgesic effect in a rat model of neuropathic pain at various routes of administration. Mechanical allodynia was induced by chronic constriction injury (CCI) of the sciatic nerve in male Sprague-Dawley rats. Subcutaneous treatment of the animals with CP-101,606 at 10 mg/kg significantly inhibited CCI-induced mechanical allodynia. Intracerebroventricular injection of CP-101,606 at 10, 30 and 100 nmol also inhibited the mechanical allodynia in a dose-dependent manner, the statistically significant effect being achieved at the highest dose tested (100 nmol) without producing any behavioral abnormalities. However, intrathecal injection of CP-101,606 at a dose of 300 nmol failed to inhibit CCI-induced allodynia. A receptor binding assay using rat forebrain and spinal cord membrane preparations demonstrated that [<sup>3</sup>H]CP-101,606 bound to the brain NR2B receptor with a greater extent compared to the spinal cord one. These findings suggest that the anti-allodynia effect of CP-101,606 is ascribable to blockade of NR2B receptors at the brain, but not at the spinal cord. In contrast, intrathecal injection of a non-selective NMDA antagonist, memantine, significantly inhibited CCI-induced mechanical allodynia at a dose of 300 nmol, indicating the difference in the site of action between the non-selective NMDA antagonist and the NR2B-specific NMDA antagonist.
Therapeutic Potential of New Pt(II) and Ru(III) Triazole-Pyrimidine Complexes against <i>Leishmania donovani</i>
Authors: Magán Rosa , Marín Clotilde , Rosales María Jose , Salas Juan Manuel , Sánchez-Moreno Manuel 
Published: October 2004

We have already established an in vitro culture system using murine macrophages infected with <i>Leishmania donovani</i> in which the time course of parasite growth is determined quantitatively. We adopted this system for the screening of three triazole-pyrimidine derivatives that would ideally prove to be effective against <i>L. donovani</i> with no toxicity to the host cell. Amphotericin B deoxycholate was used as the standard drug and gave a IC<sub>50</sub> value of 3.89 µg/ml. The three triazole-pyrimidine compounds assayed have been reported to be potent growth inhibitors of <i>L. donovani</i> promastigote and amastigote stages. Compounds SPIV and SPVI exhibited the highest toxicity for extracellular forms of parasites, with IC<sub>50</sub> values of 19.95 and 21.61 µg/ml, respectively. The triazole-pyrimidine SPV, although to a lower degree, also showed pronounced effects against promastigote forms with IC<sub>50</sub> of 33.14 µg/ml. Drug activity was higher against amastigote than against promastigote stages. The compounds SPIV and SPVI interfered with the synthesis of macromolecules, affecting primarily DNA at the lower concentration tested (5 µg/ml), while SPV also showed interference, though to a lesser extent, and at a higher concentration (15 µg/ml) the percentage of inhibition rose considerably. The synthesis or RNA and proteins was also depressed significantly by these compounds at administration rates of 15 µg/ml. Ultrastructural alterations were evident in the main organelles of <i>L. donovani</i> (nucleus, kinetoplast, mitochondria), after the addition of the three compounds at a concentration of 5 µg/ml, to the in vitro culture. The in vitro promastigote forms of <i>L. donovani</i> can degrade glucose to carbon dioxide, and part of the carbon skeleton of the glucose is excreted as end metabolites. The excretion of these metabolites, mainly acetate, was also inhibited by the three compounds assayed, suggesting that this could be due to a direct effect on some of the enzymes related to this fermentation pathway or to the inhibition exerted by the compounds on enzyme synthesis.
Frameless Localization for Functional Neurosurgical Procedures: A Preliminary Accuracy Study
Authors: Henderson Jaimie M. 
Published: October 2004

<i>Background:</i> Targeting for functional stereotactic procedures is traditionally carried out in a noninteractive fashion, without real-time positional feedback. In addition, stereotactic frames are uncomfortable for patients and may impede intraoperative neurological evaluation. As an initial step toward a fully frameless approach to functional surgery, we have investigated the use of an image-guided microdrive coupled to a stereotactic frame system. <i>Methods:</i> For initial laboratory tests, a stereotactic phantom was imaged using high-resolution CT scanning. Three representative targets were chosen within the phantom. Targeting was carried out in the usual fashion using the StealthStation planning suite, utilizing the Radionics CRW system. An LED-equipped reference arc was attached to the CRW base ring. Registration of the base ring was accomplished using a spherical probe. A custom-built microdrive was fitted with an LED array, mounted on the CRW arc and tracked by the StealthStation. The distance between the Stealth real-time localization and the CRW localization was measured on-screen. To evaluate the accuracy of the system in the operating room, a similar procedure was carried out in 13 functional neurosurgical operations (pallidotomy or deep brain stimulator placement). <i>Results:</i> Errors of localization in the laboratory setting ranged from 0.53 to 0.70 mm. In 11 operative cases, the average difference between the CRW localization and the Stealth localization was 1.77 mm. In the remaining 2 cases, equipment malfunction prevented measurement of localization error. <i>Conclusions:</i> Frameless image-guided localization compares favorably to targeting performed noninteractively. In addition, real-time positional feedback confers advantages in target region visualization and confidence in placement of lesions and stimulators for functional procedures. With small improvements in accuracy and system reliability, fully frameless functional procedures could be safely carried out.
Low dose pramipexole is neuroprotective in the MPTP mouse model of Parkinson's disease, and downregulates the dopamine transporter via the D3 receptor
Authors: Joyce Jeffrey N , Woolsey Cheryl , Ryoo Han , Borwege Sabine , Hagner Diane 
Published: October 2004

Abstract

Background

Our aim was to determine if pramipexole, a D3 preferring agonist, effectively reduced dopamine neuron and fiber loss in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model when given at intraperitoneal doses corresponding to clinical doses. We also determined whether subchronic treatment with pramipexole regulates dopamine transporter function, thereby reducing intracellular transport of the active metabolite of MPTP, 1-methyl-4-phenylpyridinium (MPP+).

Methods

Ten 12-month old C57BL/6 mice were treated with MPTP (or saline) twice per day at 20 mg/kg s.c. (4 injections over 48 h). Mice were pretreated for 3 days and during the 2-day MPTP regimen with pramipexole (0.1 mg/kg/day) or saline. Stereological quantification of dopamine neuron number and optical density measurement of dopamine fiber loss were carried out at 1 week after treatment, using immunostaining for dopamine transporter (DAT) and tyrosine hydroxylase (TH). Additional wild-type (WT) and D3 receptor knockout (KO) mice were treated for 5 days with pramipexole (0.1 mg/kg/day) or vehicle. The kinetics of [3H]MPP+ and [3H]DA uptake (Vmax and Km) were determined 24 h later; and at 24 h and 14 days dopamine transporter density was measured by quantitative autoradiography.

Results

Pramipexole treatment completely antagonized the neurotoxic effects of MPTP, as measured by substantia nigra and ventral tegmental area TH-immunoreactive cell counts. MPTP- induced loss of striatal innervation, as measured by DAT-immunoreactivity, was partially prevented by pramipexole, but not with regard to TH-IR. Pramipexole also reduced DAT- immunoreactivity in non-MPTP treated mice. Subchronic treatment with pramipexole lowered the Vmax for [3H]DA and [3H]MPP+ uptake into striatal synaptosomes of WT mice. Pramipexole treatment lowered Vmax in WT but not D3 KO mice; however, D3 KO mice had lower Vmax for [3H]DA uptake. There was no change in DAT number in WT with pramipexole treatment or D3 KO mice at 24 h post-treatment, but there was a reduction in WT-pramipexole treated and not in D3 KO mice at 14 days post-treatment.

Conclusion

These results suggest that protection occurs at clinically suitable doses of pramipexole. Protection could be due to a reduced amount of MPP+ taken up into DA terminals via DAT. D3 receptor plays an important role in this regulation of transporter uptake and availability.
Significance of MDR1 and multiple drug resistance in refractory human epileptic brain
Authors: Marchi Nicola , Hallene Kerri L , Kight Kelly M , Cucullo Luca , Moddel Gabriel , Bingaman William , Dini Gabriele , Vezzani Annamaria , Janigro Damir 
Published: October 2004

Abstract
Background
The multiple drug resistance protein (MDR1/P-glycoprotein) is overexpressed in glia and blood-brain barrier (BBB) endothelium in drug refractory human epileptic tissue. Since various antiepileptic drugs (AEDs) can act as substrates for MDR1, the enhanced expression/function of this protein may increase their active extrusion from the brain, resulting in decreased responsiveness to AEDs.

Methods
Human drug resistant epileptic brain tissues were collected after surgical resection. Astrocyte cell cultures were established from these tissues, and commercially available normal human astrocytes were used as controls. Uptake of fluorescent doxorubicin and radioactive-labeled Phenytoin was measured in the two cell populations, and the effect of MDR1 blockers was evaluated.
Frozen human epileptic brain tissue slices were double immunostained to locate MDR1 in neurons and glia. Other slices were exposed to toxic concentrations of Phenytoin to study cell viability in the presence or absence of a specific MDR1 blocker.

Results
MDR1 was overexpressed in blood vessels, astrocytes and neurons in human epileptic drug-resistant brain. In addition, MDR1-mediated cellular drug extrusion was increased in human 'epileptic' astrocytes compared to 'normal' ones. Concomitantly, cell viability in the presence of cytotoxic compounds was increased.

Conclusions
Overexpression of MDR1 in different cell types in drug-resistant epileptic human brain leads to functional alterations, not all of which are linked to drug pharmacokinetics. In particular, the modulation of glioneuronal MDR1 function in epileptic brain in the presence of toxic concentrations of xenobiotics may constitute a novel cytoprotective mechanism.
A further critique of the analytic strategy of adjusting for covariates to identify biologic mediation
Authors: Kaufman Jay S , MacLehose Richard F , Kaufman Sol 
Published: October 2004

Abstract
Background
Epidemiologic research is often devoted to etiologic investigation, and so techniques that may facilitate mechanistic inferences are attractive. Some of these techniques rely on rigid and/or unrealistic assumptions, making the biologic inferences tenuous. The methodology investigated here is effect decomposition: the contrast between effect measures estimated with and without adjustment for one or more variables hypothesized to lie on the pathway through which the exposure exerts its effect. This contrast is typically used to distinguish the exposure's indirect effect, through the specified intermediate variables, from its direct effect, transmitted via pathways that do not involve the specified intermediates.

Methods
We apply a causal framework based on latent potential response types to describe the limitations inherent in effect decomposition analysis. For simplicity, we assume three measured binary variables with monotonic effects and randomized exposure, and use difference contrasts as measures of causal effect. Previous authors showed that confounding between intermediate and the outcome threatens the validity of the decomposition strategy, even if exposure is randomized. We define exchangeability conditions for absence of confounding of causal effects of exposure and intermediate, and generate two example populations in which the no-confounding conditions are satisfied. In one population we impose an additional prohibition against unit-level interaction (synergism). We evaluate the performance of the decomposition strategy against true values of the causal effects, as defined by the proportions of latent potential response types in the two populations.

Results
We demonstrate that even when there is no confounding, partition of the total effect into direct and indirect effects is not reliably valid. Decomposition is valid only with the additional restriction that the population contain no units in which exposure and intermediate interact to cause the outcome. This restriction implies homogeneity of causal effects across strata of the intermediate.

Conclusions
Reliable effect decomposition requires not only absence of confounding, but also absence of unit-level interaction and use of linear contrasts as measures of causal effect. Epidemiologists should be wary of etiologic inference based on adjusting for intermediates, especially when using ratio effect measures or when absence of interacting potential response types cannot be confidently asserted.