bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE SCATTERING MATRIX APPROACH FOR THE QUANTUM BLACK HOLE: AN OVERVIEW
Authors: HOOFT G. 'T 
Published: October 2004

If one assumes the validity of conventional quantum field theory in the vicinity of the horizon of a black hole, one does not find a quantum-mechanical description of the entire black hole that even remotely resembles that of conventional forms of matter; in contrast with matter made out of ordinary particles one finds that, even if embedded in a finite volume, a black hole would be predicted to have a strictly continuous spectrum. Dissatisfied with such a result, which indeed hinges on assumptions concerning the horizon that may well be wrong, various investigators have now tried to formulate alternative approaches to the problem of “quantizing” the black hole. We here review the approach based on the assumption of quantum-mechanical purity and unitarity as a starting point, as has been advocated by the present author for some time, concentrating on the physics of the states that should live on a black hole horizon. The approach is shown to be powerful in producing not only promising models for the quantum black hole, but also new insights concerning the dynamics of physical degrees of freedom in ordinary flat space–time.
REIONIZATION OF THE UNIVERSE INDUCED BY PRIMORDIAL BLACK HOLES
Authors: GIBILISCO MARINA 
Published: October 2004

The history of the universe after the recombination probably involves a reionization epoch, as the Gunn-Peterson test seems to suggest: if this is the case, the consequences of such a phenomenon should be relevant, both for the induced enhancement of the cosmic microwave background (CMB) polarization and for the possible damping of the CMB fluctuations on small angular scales (θ~1º). In this paper, I will study a model of reionization at redshifts z≤60 caused by the evaporation of primordial black holes; photon emission only from nonrotating black holes is considered. A system of coupled differential equations, giving the time evolution of the ionization degree x, of the plasma temperature Te and of the photon number density nγ, is solved in an analytical way: the results obtained show that such a kind of reionization is possible, being able to increase the ionization degree of the universe from a value x=0.002 (just after the recombination) to values near 1 (when the black holes evaporation ends). In particular, taking the evaporation redshift equal to the reionization redshift zR, one obtains total reionization (i.e. x=1) for 15≤zR≤30, while only a partial effect (x~0.75÷0.90) is present for higher values of zR (40≤zR≤60). The fast increase of x seems to agree with the predictions of an exponential reionization model discussed in a previous study of the CMB polarization induced by gravitational waves. The evolution of the plasma temperature Te is also estimated: it is affected in a less important way by the primordial black holes evaporation process, as we expect from the experimental FIRAS upper limit on the comptonization parameter yc (yc<2.5×10−5). The photoionization process here studied seems generally able to maintain the plasma in a ionized state without heating it up at very high temperatures; however, an improvement in the numerical calculation of Te is necessary in order to take into account in a more satisfactory way the collisional and excitation cooling, that can limit the increase of the plasma temperature. In this model, the density of primordial black holes (PBH’s) necessary to give a nonnegligible reionization is an important parameter: here I will consider various birth times tin and various initial density for the PBH’s, showing that the most effective reionization is obtained for zR≤30 and for PBH’s formed at tin~10−28 secafter the big bang. An estimate of their present density for this formation time gives a value ρ0=2.44×10−38g cm−3, corresponding to a present density parameter ΩPBH equal to 5.20×10−9. This result agrees with the experimental upper limit ΩPBH≤(7.6±2.6)×10−9 h(−1.95±0.15) A future improvement of this work will consider also massive particle emission from both rotating and nonrotating black holes and a spectrum taking also into account quarks and gluons jets emission.
BUSINESS ANGEL NETWORKS: A EUROPEAN PERSPECTIVE
Authors: AERNOUDT RUDY , ERIKSON TRULS 
Published: October 2004

This paper highlights the importance of business angel networks, as a tool of stimulating an entrepreneurial culture and small business financing. It also sheds light on current practices and the dimensions of business angels in Europe. A study made in 1998 for the European Commission suggests that the potential for investments by business angels is estimated to be between 10 and 20 billion € [Euro] per year. This can be compared with the 3 million Euro in seed and startup investments made in 1999 by the venture capital industry. A remarkable difference, which deserves further attention. This particular inquiry includes a brief benchmarking exercise on informal private investor networks, known as business angel networks. The background for this study is the underlying thesis that the potential for investments through business angels is insufficiently developed. Implications for policy makers and future research are discussed.
Comroe's study of aortic chemoreceptors: a path well chosen
Authors: Neubauer Judith A. 
Published: October 2004

This essay looks at the historical significance of an APS classic paper that is freely available online Comroe JH Jr. The location and function of the chemoreceptors of the aorta. Am J Physiol 127: 176—191, 1939 ( http://ajplegacy.physiology.org/cgi/reprint/127/1/176 ).
First electrodes for blood Po2 and Pco2 determination
Authors: Severinghaus John W. 
Published: October 2004

This essay looks at the historical significance of an APS classic paper that is freely available online: Severinghaus JW and Bradley AF. Electrodes for blood Po2 and Pco2 determination. J Appl Physiol 13: 515—520, 1958 ( http://jap.physiology.org/cgi/reprint/13/3/515 ).
Annexin A2 mediates endothelial cell activation by antiphospholipid/anti-β2 glycoprotein I antibodies
Authors: Zhang Jianwei , McCrae Keith R. 
Published: October 2004

AbstractPatients with antiphospholipid antibodies (APLAs) are at increased risk for arterial and venous thrombosis. Many APLAs associated with these events react with β2 glycoprotein I (β2GPI), and endothelial cell reactive antibodies that activate endothelial cells in a β2GPI-dependent manner occur commonly in these patients. We previously reported that β2GPI binds with high affinity to annexin A2 on the endothelial surface, though the relevance of this interaction to APLA/anti-β2GPI antibody–induced endothelial activation has not been determined. In this report, we confirm that anti-β2GPI antibodies activate endothelial cells in the presence of β2GPI, and demonstrate that anti–annexin A2 antibodies directly cause endothelial cell activation of a similar magnitude and with a similar time course. Moreover, bivalent anti–annexin A2 F(ab′)2 fragments also caused endothelial cell activation, whereas monomeric Fab fragments not only did not cause activation, but blocked activation induced by anti–annexin A2 antibodies and F(ab′)2 fragments, as well as that caused by anti-β2GPI antibodies in the presence of β2GPI. These observations suggest a novel pathway for endothelial activation induced by APLA/anti-β2GPI antibodies that is initiated by cross-linking or clustering of annexin A2 on the endothelial surface.
Differential regulation of virus-specific T-cell effector functions following activation by peptide or innate cytokines
Authors: Beadling Carol , Slifka Mark K. 
Published: October 2004

AbstractRobust CD8+ T-cell activation is vital for the recovery from many viral infections and is orchestrated via the integration of signals delivered through surface molecules, including the T-cell antigen receptors (TcRs) and cytokine receptors. Little is known about how virus-specific T cells interpret sequential or combined stimulation through these receptors, which must undoubtedly occur in vivo during antiviral immune responses. When measured in real time, peptide antigen and the cytokines, interleukin 12 (IL-12) and IL-18, independently regulate the on/off kinetics of protective (interferon γ, tumor necrosis factor α) and immunomodulatory (IL-2, CD40L) cytokine production by activated T cells and memory T cells. The remarkable differences in effector functions elicited by innate or adaptive signals (IL-12/ IL-18 or peptide, respectively) illustrate the complex and stringent regulation of cytokine expression by CD8+ T cells. Together, these results indicate how antiviral T cells incorporate multiple signals from their local microenvironment and tailor their cytokine responses accordingly.
RNA integrity as a quality indicator during the first steps of RNP purifications : A comparison of yeast lysis methods
Authors: López de Heredia Miguel , Jansen Ralf-Peter 
Published: October 2004

Abstract
Background
The completion of several genome-sequencing projects has increased our need to assign functions to newly identified genes. The presence of a specific protein domain has been used as the determinant for suggesting a function for these new genes. In the case of proteins that are predicted to interact with mRNA, most RNAs bound by these proteins are still unknown. In yeast, several protocols for the identification of protein-protein interactions in high-throughput analyses have been developed during the last years leading to an increased understanding of cellular proteomics. If any of these protocols or similar approaches shall be used for the identification of mRNA-protein complexes, the integrity of mRNA is a critical factor.

Results
We compared the effect of different lysis protocols on RNA integrity. We report dramatic differences in RNA stability depending on the method used for yeast cell lysis. Glass bead milling and French Press lead to degraded mRNAs even in the presence of RNase inhibitors. Thus, they are not suitable to purify intact mRNP complexes or to identify specific mRNAs bound to proteins.

Conclusion
We suggest a novel protocol, grinding deep-frozen cells, for the preparation of protein extracts that contain intact RNAs, as lysis method for the purification of mRNA-protein complexes from yeast cells.
A comprehensive comparison of comparative RNA structure prediction approaches
Authors: Gardner Paul P , Giegerich Robert 
Published: October 2004

Abstract
Background
An increasing number of researchers have released novel RNA structure analysis and prediction algorithms for comparative approaches to structure prediction. Yet, independent benchmarking of these algorithms is rarely performed as is now common practice for protein-folding, gene-finding and multiple-sequence-alignment algorithms.

Results
Here we evaluate a number of RNA folding algorithms using reliable RNA data-sets and compare their relative performance.

Conclusions
We conclude that comparative data can enhance structure prediction but structure-prediction-algorithms vary widely in terms of both sensitivity and selectivity across different lengths and homologies. Furthermore, we outline some directions for future research.
Is autoinducer-2 a universal signal for interspecies communication: a comparative genomic and phylogenetic analysis of the synthesis and signal transduction pathways
Authors: Sun Jibin , Daniel Rolf , Wagner-Döbler Irene , Zeng An-Ping 
Published: October 2004

Abstract
Background
Quorum sensing is a process of bacterial cell-to-cell communication involving the production and detection of extracellular signaling molecules called autoinducers. Recently, it has been proposed that autoinducer-2 (AI-2), a furanosyl borate diester derived from the recycling of S-adenosyl-homocysteine (SAH) to homocysteine, serves as a universal signal for interspecies communication.

Results
In this study, 138 completed genomes were examined for the genes involved in the synthesis and detection of AI-2. Except for some symbionts and parasites, all organisms have a pathway to recycle SAH, either using a two-step enzymatic conversion by the Pfs and LuxS enzymes or a one-step conversion using SAH-hydrolase (SahH). 51 organisms including most Gamma-, Beta-, and Epsilonproteobacteria, and Firmicutes possess the Pfs-LuxS pathway, while Archaea, Eukarya, Alphaproteobacteria, Actinobacteria and Cyanobacteria prefer the SahH pathway. In all 138 organisms, only the three Vibrio strains had strong, bidirectional matches to the periplasmic AI-2 binding protein LuxP and the central signal relay protein LuxU. The initial two-component sensor kinase protein LuxQ, and the terminal response regulator luxO are found in most Proteobacteria, as well as in some Firmicutes, often in several copies.

Conclusions
The genomic analysis indicates that the LuxS enzyme required for AI-2 synthesis is widespread in bacteria, while the periplasmic binding protein LuxP is only present in Vibrio strains. Thus, other organisms may either use components different from the AI-2 signal transduction system of Vibrio strains to sense the signal of AI-2, or they do not have such a quorum sensing system at all.
On modeling locus heterogeneity using mixture distributions
Authors: Lin Shili , Biswas Swati 
Published: October 2004

Abstract
Background
Locus heterogeneity poses a major difficulty in mapping genes that influence complex genetic traits. A widely used approach to deal with this problem involves modeling linkage data in terms of finite mixture distributions. In its simplest setup, also known as the admixture approach, a single parameter is used to model the probability that the disease-causing gene of a family is linked to a reference marker. This parameter is usually interpreted as the overall proportion of linked families.

Results
In this article, we address two issues regarding the admixture approach. First, we tackle the question of whether the single parameter of linked proportion is well defined in general. By formulating the likelihood under a classification scheme based on distributions, we show that such a parameter is meaningful only when a certain well-characterized condition is met. Second, we study a condition given in the literature for validating the admixture approach. A counter example is constructed to illustrate that the condition does not necessarily lead to valid estimates.

Conclusions
Estimators from the admixture approach may be inconsistent. This holds even if a condition given in the literature to validate the approach is satisfied.
Diagnostic polymorphisms in the mitochondrial cytochrome b gene allow discrimination between cattle, sheep, goat, roe buck and deer by PCR-RFLP
Authors: Pfeiffer Ina , Burger Joachim , Brenig Bertram 
Published: October 2004

Abstract
Background
As an alternative to direct DNA sequencing of PCR products, random PCR-RFLP is an efficient technique to discriminate between species. The PCR-RFLP-method is an inexpensive tool in forensic science, even if the template is degraded or contains only traces of DNA from various species.

Results
Interspecies-specific DNA sequence polymorphisms in the mitochondrial cytochrome b gene were analyzed using PCR-RFLP technology to determine the source (i.e., species) of blood traces obtained from a leaf.

Conclusions
The method presented can be used for the discrimination of cattle (Bos taurus), sheep (Ovis aries), goat (Capra hircus), roe buck (Capreolus capreolus) and red deer (Cervus elaphus).
Effect of straining on diaphragmatic crura with identification of the straining-crural reflex. The "reflex theory" in gastroesophageal competence
Authors: Shafik Ahmed , Shafik Ali A , El Sibai Olfat , Mostafa Randa M 
Published: October 2004

Abstract
Background
The role of the crural diaphragm during increased intra-abdominal pressure is not exactly known. We investigated the hypothesis that the crural diaphragm undergoes reflex phasic contraction on elevation of the intra-abdominal pressure with a resulting increase of the lower esophageal pressure and prevention of gastro-esophageal reflux.

Methods
The esophageal pressure and crural diaphragm electromyographic responses to straining were recorded in 16 subjects (10 men, 6 women, age 36.6 ± 11.2 SD years) during abdominal hernia repair. The electromyogram of crural diaphragm was recorded by needle electrode inserted into the crural diaphragm, and the lower esophageal pressure by a saline-perfused catheter. The study was repeated after crural anesthetization and after crural infiltration with saline.

Results
The crural diaphragm exhibited resting electromyographic activity which showed a significant increase on sudden (coughing, p < 0.001) or slow sustained (p < 0.01) straining with a mean latency of 29.6 ± 4.7 and 31.4 ± 4.5 ms, respectively. Straining led to elevation of the lower esophageal pressure which was coupled with the increased electromyographic activity of the crural diaphragm. The crural response to straining did not occur during crural diaphragm anesthetization, while was not affected by saline infiltration. The lower esophageal pressure declined on crural diaphragm anesthetization.

Conclusions
Straining effected an increase of the electromyographic activity of the crural diaphragm and of the lower esophageal pressure. This effect is suggested to be reflex in nature and to be mediated through the "straining-crural reflex". The crural diaphragm seems to play a role in the lower esophageal competence mechanism. Further studies are required to assess the clinical significance of the current results in gastro-esophageal reflux disease and hiatus hernia.
Randomised controlled trial of gabapentin in Complex Regional Pain Syndrome type 1 [ISRCTN84121379]
Authors: van de Vusse Anton C , Stomp-van den Berg Suzanne GM , Kessels Alfons HF , Weber Wim EJ 
Published: October 2004

Abstract
Background
Complex Regional Pain Syndrome type one (CRPS I) or formerly Reflex Sympathetic Dystrophy (RSD) is a disabling syndrome, in which a painful limb is accompanied by varying symptoms. Neuropathic pain is a prominent feature of CRPS I, and is often refractory to treatment. Since gabapentin is an anticonvulsant with a proven analgesic effect in various neuropathic pain syndromes, we sought to study the efficacy of the anticonvulsant gabapentin as treatment for pain in patients with CRPS I.

Methods
We did a randomized double blind placebo controlled crossover study with two three-weeks treatment periods with gabapentin and placebo separated by a two-weeks washout period. Patients started at random with gabapentin or placebo, which was administered in identical capsules three times daily. We included 58 patients with CRPS type 1.

Results
Patients reported significant pain relief in favor of gabapentin in the first period. Therapy effect in the second period was less; finally resulting in no significant effect combining results of both periods. The CRPS patients had sensory deficits at baseline. We found that this sensory deficit was significantly reversed in gabapentin users in comparison to placebo users.

Conclusions
Gabapentin had a mild effect on pain in CRPS I. It significantly reduced the sensory deficit in the affected limb. A subpopulation of CRPS patients may benefit from gabapentin.
Mechanisms underlying fatigue: a voxel-based morphometric study of chronic fatigue syndrome
Authors: Okada Tomohisa , Tanaka Masaaki , Kuratsune Hirohiko , Watanabe Yasuyoshi , Sadato Norihiro 
Published: October 2004

Abstract
Background
Fatigue is a crucial sensation that triggers rest, yet its underlying neuronal mechanisms remain unclear. Intense long-term fatigue is a symptom of chronic fatigue syndrome, which is used as a model to study the mechanisms underlying fatigue.

Methods
Using magnetic resonance imaging, we conducted voxel-based morphometry of 16 patients and 49 age-matched healthy control subjects.

Results
We found that patients with chronic fatigue syndrome had reduced gray-matter volume in the bilateral prefrontal cortex. Within these areas, the volume reduction in the right prefrontal cortex paralleled the severity of the fatigue of the subjects.

Conclusion
These results are consistent with previous reports of an abnormal distribution of acetyl-L-carnitine uptake, which is one of the biochemical markers of chronic fatigue syndrome, in the prefrontal cortex. Thus, the prefrontal cortex might be an important element of the neural system that regulates sensations of fatigue.
Chemotherapy with cisplatin and vinorelbine for elderly patients with locally advanced or metastatic non-small-cell lung cancer (NSCLC)
Authors: Pereira José Rodrigues , Martins Sandro J , Nikaedo Sueli M , Ikari Flora K 
Published: October 2004

Abstract
Background
Although modest improvements in the survival of patients with non-small cell lung cancer (NSCLC) can be achieved with cisplatin-based chemotherapy (CT), its value is disputed in the geriatric setting. In this study, we evaluate the feasibility of vinorelbine/cisplatin CT for elderly NSCLC patients.

Methods
In this pilot phase I/II trial, all patients received CT with vinorelbine 25 mg/m2, on day 1 and 8, and cisplatin on day 1, in 28 days-cycles. After stratification for age (up to 75 years), younger patients were sequentially allocated to moderate cisplatin doses (80 mg/m2 or 90 mg/m2), and older patients were allocated to lower cisplatin doses (60 mg/m2 or 70 mg/m2). We recruited patients aged over 70 years with newly diagnosed NSCLC, clinical stage III or IV, Karnofsky performance status ≥ 70%, normal serum creatinine, peripheral neuropathy ≤ grade 1, and no prior cancer therapy.

Results
Analysis was by intention to treat. Main toxicities (grade 3–4) was as follows: neutropenia, 20%; anemia, 11%; and thrombocytopenia, 2%; alopecia, 55%; fatigue, 11%; and peripheral neurotoxicity, 2%. No grade 3–4 emesis or renal toxicity occurred. Global median time to progression (TTP) and overall survival (OS) were 27.0 (95% CI: 10.1 to 43.7) weeks and 30.1 (95% CI: 24.4 to 35.8) weeks; 1- and 2-year survival rates were 36.3% and 13.2%, respectively. Overall response rate was 50.0% (95% CI: 35.4% to 64.5%), with 1 complete response; no difference on response rate was noticed according to cisplatin dose. Median overall survival was 30.1 weeks, with 1- and 2-year survival rates of 36.3% and 13.2%, respectively.

Conclusion
Age does not preclude assessment on the role of cisplatin-vinorelbine CT for elderly NSCLC patients with good performance status and adequate bodily functions.