julilili42/papers huggingface dataset:
Systematic Review of Early Recurrent Stenosis After Carotid Angioplasty and Stenting
2004-12-30

Background and Purpose— Carotid angioplasty and stenting (CAS) has emerged as a potential alternative to endarterectomy (CEA) for the treatment of carotid artery disease. Aside from the periprocedural complication rates, the benefits of CAS will be affected by the incidence of recurrent carotid stenosis. Methods— We conducted a systematic analysis of all peer-reviewed studies reporting on the rate of restenosis (≥50%) after CAS based on duplex ultrasound or angiography that were published between January 1990 and July 2004. We identified 34 studies that reported on a total of 4185 patients with a follow-up of 3814 arteries over a median of 13 months (range, 6 to 31 months). The ultrasound criteria and the lower thresholds for defining a recurrent stenosis were very heterogeneous. Results— The cumulative restenosis rates after 1 and 2 years were ≈6% and 7.5% in those studies, which used a lower restenosis threshold ≥50% to 70% and ≈4% in the first 2 years after CAS in those studies, which used a lower restenosis threshold &gt;70% to 80%. Conclusions— In reviewing the current literature, the early restenosis rates after CAS compare well with those reported for CEA. However, this analysis of the peer-reviewed literature also indicates that the early restenosis rates after CAS might be higher than previously suggested in observational surveys. Therefore, an active follow-up of all stented arteries seems to be warranted. Moreover, the bulk of endovascular data are derived from small studies with short follow-up periods so that the long-term durability of CAS still needs to be established in large trials. Ideally, these studies should use a clear and uniform definition of restenosis and identical follow-up schedules.
Fluid pumped by magnetic stress
2004-12-30

A magnetic field rotating on the free surface of a ferrofluid layer is shown to induce considerable fluid motion toward the direction the field is rolling. The measured flow velocity (i) increases with the square of the magnetic field amplitude, (ii) is proportional to the thickness of the fluid layer, and (iii) has a maximum at a driving frequency of about 3kHz. The pumping speed can be estimated with a two-dimensional flow model.
Psychobiology of Altered States of Consciousness.
2005-01-01

The article reviews the current knowledge regarding altered states of consciousness (ASC) (a) occurring spontaneously, (b) evoked by physical and physiological stimulation, (c) induced by psychological means, and (d) caused by diseases. The emphasis is laid on psychological and neurobiological approaches. The phenomenological analysis of the multiple ASC resulted in 4 dimensions by which they can be characterized: activation, awareness span, self-awareness, and sensory dynamics. The neurophysiological approach revealed that the different states of consciousness are mainly brought about by a compromised brain structure, transient changes in brain dynamics (disconnectivity), and neurochemical and metabolic processes. Besides these severe alterations, environmental stimuli, mental practices, and techniques of self-control can also temporarily alter brain functioning and conscious experience.
Geomicrobiological Cycling of Iron
2005-01-01

Research Article| January 01, 2005 Geomicrobiological Cycling of Iron Andreas Kappler; Andreas Kappler Geomicrobiology Group, Center for Applied Geosciences, University of Tübingen, D-72074 Tübingen, Germany, andreas.kappler@uni-tuebingen.de, kristina.straub@uni-tuebingen.de Search for other works by this author on: GSW Google Scholar Kristina L. Straub Kristina L. Straub Geomicrobiology Group, Center for Applied Geosciences, University of Tübingen, D-72074 Tübingen, Germany, andreas.kappler@uni-tuebingen.de, kristina.straub@uni-tuebingen.de Search for other works by this author on: GSW Google Scholar Author and Article Information Andreas Kappler Geomicrobiology Group, Center for Applied Geosciences, University of Tübingen, D-72074 Tübingen, Germany, andreas.kappler@uni-tuebingen.de, kristina.straub@uni-tuebingen.de Kristina L. Straub Geomicrobiology Group, Center for Applied Geosciences, University of Tübingen, D-72074 Tübingen, Germany, andreas.kappler@uni-tuebingen.de, kristina.straub@uni-tuebingen.de Publisher: Mineralogical Society of America First Online: 09 Mar 2017 © The Mineralogical Society Of America Reviews in Mineralogy and Geochemistry (2005) 59 (1): 85–108. https://doi.org/10.2138/rmg.2005.59.5 Article history First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Andreas Kappler, Kristina L. Straub; Geomicrobiological Cycling of Iron. Reviews in Mineralogy and Geochemistry 2005;; 59 (1): 85–108. doi: https://doi.org/10.2138/rmg.2005.59.5 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyReviews in Mineralogy and Geochemistry Search Advanced Search Iron is the most abundant element on Earth and the most frequently utilized transition metal in the biosphere. It is a component of many cellular compounds and is involved in numerous physiological functions. Hence, iron is an essential micronutrient for all eukaryotes and the majority of prokaryotes. Prokaryotes that need iron for biosynthesis require micromolar concentrations, levels that are often not available in neutral pH oxic environments. Therefore, prokaryotes have evolved specific acquisition molecules, called siderophores, to increase iron bioavailability. Acquisition of iron by siderophores is a complex process and is discussed in detail by Kraemer et al. (2005).... You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Mechanisms of Suicidal Erythrocyte Death
2005-01-01

Erythrocyte injury such as osmotic shock, oxidative stress or energy depletion stimulates the formation of prostaglandin E2 through activation of cyclooxygenase which in turn activates a Ca2+ permeable cation channel. Increasing cytosolic Ca2+ concentrations activate Ca2+ sensitive K+ channels leading to hyperpolarization, subsequent loss of KCl and (further) cell shrinkage. Ca2+ further stimulates a scramblase shifting phosphatidylserine from the inner to the outer cell membrane. The scramblase is sensitized for the effects of Ca2+ by ceramide which is formed by a sphingomyelinase following several stressors including osmotic shock. The sphingomyelinase is activated by platelet activating factor PAF which is released by activation of phospholipase A2. Phosphatidylserine at the erythrocyte surface is recognised by macrophages which engulf and degrade the affected cells. Moreover, phosphatidylserine exposing erythrocytes may adhere to the vascular wall and thus interfere with microcirculation. Erythrocyte shrinkage and phosphatidylserine exposure ('eryptosis') mimic features of apoptosis in nucleated cells which however, involves several mechanisms lacking in erythrocytes. In kidney medulla, exposure time is usually too short to induce eryptosis despite high osmolarity. Beyond that high Cl- concentrations inhibit the cation channel and high urea concentrations the sphingomyelinase. Eryptosis is inhibited by erythropoietin which thus extends the life span of circulating erythrocytes. Several conditions trigger premature eryptosis thus favouring the development of anemia. On the other hand, eryptosis may be a mechanism of defective erythrocytes to escape hemolysis. Beyond their significance for erythrocyte survival and death the mechanisms involved in 'eryptosis' may similarly contribute to apoptosis of nucleated cells.
Axially modified gallium phthalocyanines and naphthalocyanines for optical limiting
2005-01-01

Phthalocyanines (Pcs) offer a high architectural flexibility in structure, which facilitates the tailoring of their physical, optoelectronic and chemical parameters over a very broad range. This tutorial review describes the recent advances in the synthesis of soluble axially substituted or bridged gallium phthalo- and naphthalocyanine compounds, and their photophysical and nonlinear optical properties. The exploitation of the chemical reactivity of the Ga-Cl bond can allow the preparation of a series of highly soluble axially substituted and bridged Pc complexes. Axial substituents in Pcs influence favourably nonlinear optical absorption for the presence of a dipole moment perpendicular to the macrocycle in the axially substituted phthalocyanines. All Z-scans performed exhibit a decrease of transmittance about the focus typical of an induced positive nonlinear absorption of incident light. Substitution and dimerization of the phthalocyanine monomer resulted in significant reductions in the saturation energy density of the material displaying clear evidence of the usefulness of structurally modifying the gallium phthalocyanine unit. Similar to indium phthalocyanines, gallium phthalocyanines are also among the most promising materials that have been investigated as limiters of intense light and the current series presents a selection of structural modifications useful for varying their nonlinear optical properties.
The RAS/RAF/MEK/ERK and PI3K/AKT signaling pathways present molecular targets for the effective treatment of advanced melanoma
2005-01-01

Malignant melanoma is a highly aggressive tumor of the pigment-producing cells in the skin with a rapidly increasing incidence and a poor prognosis for patients with advanced disease that is resistant to current therapeutic concepts. Therefore, the development of novel strategies for treating melanoma are of utmost importance. In melanoma, both the Ras-Raf-MEK-ERK (MAPK) and the PI3K-AKT (AKT) signaling pathways are constitutively activated through multiple mechanisms, and thus exert several key functions in melanoma development and progression. Conversely, several molecules known to play key roles in melanoma development and progression such as the adhesion molecules E-/N-cadherin, MelCAM and alphavbeta3 integrin are regulated by these pathways and/or activate the same. The results of the research to date indicate that in melanoma both the MAPK and the AKT signaling pathways may represent promising therapeutic targets.
The correlation between oxidative stress and leaf senescence during plant development.
2005-01-01

In plants, besides being the final step leading to the death of the whole organism, senescence has a developmental function involving the coordinated degradation of macromolecules and the mobilization of nutrients out of senescing tissues into developing parts of the plant. Free radicals are thought to play an essential role in senescence, especially those derived from oxygen. Since these molecules are extremely toxic, the levels of the different reactive oxygen species have to be tightly regulated. However, at low concentrations, hydrogen peroxide may also serve as a signalling molecule. Therefore, a coordinated regulation of the free radical scavenging system, which comprises enzymatic components such as catalase, superoxide dismutase and ascorbate peroxidase, and non-enzymatic molecules such as ascorbate and glutathione is essential. The increased radical levels displayed during senescence are not only caused by the elevated production of radicals but also by a loss in antioxidant capacity.
Determinants and effects of foreign direct investment: evidence from German firm-level data
2005-01-01

type="main" xml:lang="en"&gt; &lt;p&gt; Foreign direct investment is an essential aspect of ‘globalization’ yet its empirical determinants are not well understood. What we do know is based either on poor data for a wide range of nations, or good data for the US and Swedish cases. In this paper, we provide evidence on the determinants of the activities of German multinational firms by using a newly available firm-level data set from the Deutsche Bundesbank. The specific goal of this paper is to demonstrate the relative role of country-level and firm-level determinants of foreign direct investment. We focus on three main questions: First, what are the main driving forces of German firms’ multinational activities? Second, is there evidence that sector-level and firm-level factors shape internationalization patterns? Third, is there evidence of agglomeration effects in the foreign activities of German firms? &lt;p&gt; We find that the market access motive for internationalization dominates. Firms move abroad mainly to gain better access to large foreign markets. Cost-saving motives, however, are important for some manufacturing sectors. Our results strongly suggest that firm-level heterogeneity has an important influence on internationalization patterns – as stressed by recent models of international trade. We also find positive agglomeration effects for the activities of German firms that stem from the number of other German firms that are active on a given foreign market. &lt;p&gt; In terms of lessons for economic policy, our results show that lowering barriers to the integration of markets and encouraging the formation of human capital can promote the activities of multinational firms. However, our results related to the heterogeneity of firms and agglomeration tendencies show that it might be difficult to fine-tune policies directed at the exploitation of synergies and at the creation of clusters of foreign firms. &lt;p&gt; — Claudia M. Buch, Jörn Kleinert, Alexander Lipponer and Farid Toubal
Alpha-Stable Branching and Beta-Coalescents
2005-01-01

We determine that the continuous-state branching processes for which the genealogy, suitably time-changed, can be described by an autonomous Markov process are precisely those arising from -stable branching mechanisms. The random ancestral partition is then a time-changed -coalescent, where is the Beta-distribution with parameters and , and the time change is given by , where is the total population size. For (Feller's branching diffusion) and (Kingman's coalescent), this is in the spirit of (a non-spatial version of) Perkins' Disintegration Theorem. For and the uniform distribution on , this is the duality discovered by Bertoin &amp; Le Gall (2000) between the norming of Neveu's continuous state branching process and the Bolthausen-Sznitman coalescent. We present two approaches: one, exploiting the `modified lookdown construction', draws heavily on Donnelly &amp; Kurtz (1999); the other is based on direct calculations with generators.
Neocortex is the major target of sedative concentrations of volatile anaesthetics: strong depression of firing rates and increase of GABAA receptor‐mediated inhibition
2005-01-01

Abstract General anaesthetics cause sedation, amnesia and hypnosis. Although these clinically desired actions are indicative of an impairment of neocortical information processing, it is widely held that they are to a large part mediated by subcortical neural networks. Anaesthetic action on brain stem, basal forebrain and thalamus, all of which are known to modulate cortical excitability, would thus ultimately converge on neocortex, perturbing and reducing action potential activity therein. However, as neocortex harbours molecular targets of anaesthetics in high densities, notably GABA A receptors, neocortex itself should be very sensitive to anaesthetics. Here, we performed experiments to reveal the extent to which neocortex proper is a relevant target of the low concentrations of volatile anaesthetics causing sedation and hypnosis. We compared the effects of isoflurane, enflurane and halothane on spontaneous action potential activity of rat neocortical neurons in vivo and in isolated cortical networks in vitro , i.e. in the presence and absence of subcortical arousal systems. We observed that the anaesthetics decreased spontaneous firing of neurons via intracortical mechanisms; concentrations inducing hypnosis in humans reduced discharge rates both in vivo and in vitro to the same extent, approximately 50%. This decrease in neuronal activity was paralleled by a significant enhancement of neocortical GABA A receptor‐mediated inhibition. These findings challenge the notion of predominantly subcortical effects of volatile anaesthetics and suggest that intracortical targets, among them neocortical GABA A receptors, mediate the sedative and hypnotic properties of volatile anaesthetics.
Somatic chromosomal abnormalities in infertile men and women
2005-01-01

Infertility – the inability to achieve conception or sustain a pregnancy through to live birth – is very common and affects about 15% of couples. While chromosomal or genetic abnormalities associated with azoospermia, severe oligozoospermia or primary ovarian failure were of no importance for reproduction prior to the era of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), advances in assisted reproductive techniques (ART) now enable many infertile couples to have children. These developments have raised the question of the genetic consequences of ICSI: concerns of the potential harm of the invasive procedure and concerns about the genetic risk. The infertile male and female definitely have an increased risk to carry a chromosomal abnormality. Detection of such an abnormality is of fundamental importance for the diagnosis of infertility, the following treatment, the evaluation of the risk for the future child and the appropriate management of the pregnancy to be obtained. Therefore, cytogenetic screening of both partners is mandatory prior to any type of ART. The present review is based on several surveys on male and female infertility and analyzes the types and frequencies of the different reported chromosome abnormalities according to the type of impairment of spermatogenesis and the type of treatment planned or performed. With regard to assisted reproductive techniques (especially ICSI) the main types of chromosomal abnormalities are discussed and their potential risks for ICSI. If available, reported cases of performed ICSI and its outcome are presented. The detection of an abnormal karyotype should lead to comprehensive genetic counselling, which should include all well-known information about the individual type of anomaly, its clinical relevance, its possible inheritance, the genetic risk of unbalanced offspring, and the possibilities of prenatal diagnosis. Only this proceeding allows at-risk couples to make an informed decision regarding whether or not to proceed with ART. These decisions can be made only when both partners have clearly understood the genetic risks and possible consequences when ART is used.
Species-specific ingestion of organic carbon by deep-sea benthic foraminifera and meiobenthos: In situ tracer experiments
2005-01-01

We measured organic carbon uptake rates by deep-sea benthic foraminifera and studied differences among species, living depth, and seasons to investigate how these protists contribute to carbon consumption on the deep-sea floor. In situ feeding experiments using 13C-labeled algae were carried out in the central part of Sagami Bay from 24 to 29 November 2001 and 1 to 12 April 2002. Our results indicate that carbon assimilation rates were higher in shallow infaunal species (Uvigerina akitaensis, Bulimina aculeata) and lower in intermediate (Textularia kattegatensis) and deep infaunal species (Chilostomella ovoidea). Some shallow and intermediate infaunal species showed higher carbon uptake in spring than in autumn. In total, benthic foraminifera assimilated C at 5.8 ± 4.8 mg m−2 and 2.0 ± 1.3 mg m−22 (in spring and in autumn, respectively) of labeled algae within 2 d, which was more than that by total metazoans (1.5 ± 0.4 mg m−2 and 0.4 ± 0.1 mg m−2, respectively). Deep-sea benthic foraminifera rapidly ingest large amounts of carbon and may play an important role in carbon consumption on the deep-sea floor. Different responses to algal carbon among species may explain foraminiferal assemblages and shifts after environmental changes, such as seasonal pulses of organic matter supply.
Small molecular anti-cytokine agents
2005-01-01

The recent successful introduction of the anti-cytokine biologicals Etanercept, Infliximab, Adalimumab, and Anakinra has stimulated the search for anti-cytokine small-molecules. A number of molecular targets have been identified for the development of such small molecular anti-cytokine agents. The focus of this review will be on those inhibitors of cytokine production, which target either p38 mitogen activated protein (MAP) kinase, TNF-alpha converting enzyme (TACE), or IL-1beta converting enzyme (ICE). P38 MAP kinase occupies a central role in the signaling network responsible for the upregulation of proinflammatory cytokines like interleukin 1beta (IL-1beta) and TNF-alpha, and regulates their biosynthesis at both the transcriptional and translational level. TACE and ICE are two proteases required for the processing of proTNF-alpha and proIL-1beta, respectively into their mature, proinflammatory form. Since the mid-1990s, a plethora of inhibitors of p38 MAP kinase, TACE, and ICE has been characterized in vitro, and individual representatives from all three inhibitor classes have in the meantime been advanced into clinical trials. This review will highlight the correlation between effective inhibition at the molecular target and cellular activity in functional assays of cytokine, particularly TNF-alpha and IL-1beta, production. Structure-activity relationships (SAR) will be discussed regarding activity at the respective enzyme target, but also with regard to properties required for efficient in vitro and in vivo cellular activity (e.g., oral availability, solubility, cell penetration, etc.).
Surveillance of patients at high risk for cutaneous malignant melanoma using digital dermoscopy
2005-01-01

Follow-up examinations using digital dermoscopy revealed unchanged morphology in the large majority of melanocytic naevi. Excisions were only performed in cases of asymmetrical growth, asymmetrical changes of pigmentation, or development of dermoscopic features indicative of melanoma. The ratio of 33 lesions excised in order to identify two melanomas in situ seems reasonable and may be further reduced in future.
Estrogen receptor-? is associated with the plasma membrane of astrocytes and coupled to the MAP/Src-kinase pathway
2005-01-01

Estrogens influence CNS development and a broad spectrum of neural functions. Several lines of evidence also suggest a neuroprotective role for estrogen. Different modes of estrogen action have been described at the cellular level involving classical nuclear estrogen receptor (ER)-dependent and nonclassical membrane ER-mediated rapid signaling. We have previously shown that nonclassical estrogen signaling is implicated in the control of dopamine cell function and protection. Since nonclassical interactions between estrogens and glia may contribute to these effects, our aim was to demonstrate the presence of membrane-associated ERs and their putative coupling to intracellular signaling pathways in astrocytes. Confocal image analysis and fluorescence-activated cell sorting (FACS) studies indicated the attachment of ER-alpha but not ER-beta to the plasma membrane of astrocytes. ERs were located in the cell soma region and glial processes. FACS analysis revealed that only a subpopulation of midbrain astrocytes possesses membrane ER-alpha. In FACS studies on ER-alpha knockout astrocytes, only a few membrane ER-positive cells were detected. The activation of membrane ERs appears to be coupled to the MAP-kinase/Src signaling pathway as shown by Western blotting. In conclusion, our data provide good evidence that nonclassical estrogen action in astrocytes is mediated by membrane ER-alpha. The physiological consequence of this phenomenon is not yet understood, but it might have a pivotal role in estrogen-mediated protective effects on midbrain dopamine neurons.