julilili42/papers huggingface dataset:
Phthalocyanines as materials for advanced technologies: some examples
2004-07-01

Metallophthalocyanine complexes and related compounds play an important role in many advanced applications and modern technologies mostly by virtue of their characteristic optical absorption and high chemical stability. As a class of materials made well-known by their vivid and fast colors, it is expected that metallophthalocyanines and analogues, e.g. naphthalocyanines, are going to keep their role with the increasing use of natural and artificial light in the technologies of the future. In the present review some relevant properties of phthalocyanines and related macrocycles for technological applications are analyzed. In particular the electrical conductivity and photoconductivity as well as some nonlinear optical properties (mostly optical limiting), of phthalocyanines and related compounds are discussed.
Taiwan's Political Parties and National Identity: The Rise of an Overarching Consensus
2004-07-01

National identity is still one of the most contentious issues in present-day Taiwan. At the surface level, the confrontation between the “pan-blue” and “pan-green” party camps suggests the existence of competing and irreconcilable national identities. However, the overall quest for Taiwanese sovereignty against Beijing's insistence on the “one country, two systems” formula suggests the rise of an overarching consensus between all political parties that reflects the fact that a Taiwanese nation already exists. Although civic in nature, this nation may soon close ranks against the idea of “one China” if Beijing does not compromise on the issue of sovereignty.
Cellular Immunotherapy with Dendritic Cells in Cancer: Current Status
2004-07-01

Dendritic cells (DCs) are specialized antigen-presenting cells whose immunogenicity leads to the induction of antigen-specific immune responses. DCs can easily be generated ex vivo from peripheral blood monocytes or bone marrow/circulating hematopoietic stem cells cultured in the presence of cytokine cocktails. DCs have been used in numerous clinical trials to induce antitumor immune responses in cancer patients. The studies carried out to date have demonstrated that DCs pulsed with tumor antigens can be safely administered, and this approach produces antigen-specific immune responses. Clinical responses have been observed in a minority of patients. It is likely that either heavy medical pretreatment or the presence of large tumor burdens (or both) is among the causes that impair the benefits of vaccination. Hence, the use of DCs should be considered in earlier stages of disease such as the adjuvant setting. Prospective applications of DCs extend to their use in allogeneic adoptive immunotherapy to specifically target the graft versus tumor reaction. DCs continue to hold promise for cellular immunotherapy, and further investigation is required to determine the clinical settings in which patients will most benefit from the use of this cellular immune adjuvant.
The Numerical Age of the Upper Frasnian (Upper Devonian) Kellwasser Horizons: A New U‐Pb Zircon Date from Steinbruch Schmidt (Kellerwald, Germany)
2004-07-01

Steinbruch Schmidt (Kellerwald, Germany) is probably the world's most famous locality that exposes the late Frasnian anoxic events (Kellwasser Crisis). A 3‐cm‐thick bentonite layer (Bed 36) is intercalated between the two Kellwasser horizons and can be precisely assigned to the Upper rhenana conodont Zone. Twenty‐four U‐Pb ID‐TIMS (isotope dilution–thermal ionization mass spectrometry) analyses of single zircons extracted from this layer yielded 17 concordant results, which form an elongated cluster along concordia. The oldest point of this cluster is assumed to represent the lowest amount of Pb loss, and its 206Pb/238U age of Ma is regarded as the eruption age of the bentonite. This dating allows the geochronological fixing of the anoxic Kellwasser horizons, which characterize one of the most important biotic crises of the Palaeozoic era, immediately prior to the Frasnian‐Famennian boundary. A biochronometric timescale of the mid‐Frasnian to late Famennian interval is established based on all recently published Late Devonian U‐Pb ID‐TIMS ages. The age of the Frasnian‐Famennian boundary can be estimated by interpolation to Ma.
FACIES AND POROPERM CHARACTERISTICS OF A CARBONATE SHOAL (MUSCHELKALK, SOUTH GERMAN BASIN): A RESERVOIR ANALOGUE INVESTIGATION
2004-07-01

Outcrop analogue investigations contribute to the understanding of the architecture and behaviour of subsurface hydrocarbon reservoirs. This study was designed to provide input for static reservoir modelling of shoal bodies on carbonate ramps. We investigated an oolitic and shelly carbonate shoal of Late Muschelkalk (late Ladinian) age, about 30 km long and 15 km wide, exposed in a series of quarries in southern Germany. The dimensions of this shoal body correspond to both modern analogues in the Persian Gulf and to oilfields in the Middle East. Fifteen outcrop locations were chosen to cover the entire shoal. A regional correlation based on facies, sequence analysis and outcrop gamma‐ray logs was used as a framework for mapping the distribution of shoal (i. e. reservoir) facies and associated reservoir properties. Three major depositional environments were recognized: foreshoal, shoal and backshoal. In each environment, specific vertical facies successions composed of thick shallowing‐upward units and thin deepening‐upward units forming metre‐scale cycles were deposited. These small‐scale cycles are stacked and form large‐scale shallowing and deepening trends. Shoal facies developed preferentially in the regressive parts of small‐scale cycles and were found to be laterally continuous over distances of at least several kilometres. Porous intervals within the shoal facies are concentrated along the tops of the small‐scale shallowing‐upward cycles. The porous intervals in successive small‐scale cycles increase in thickness and in absolute values of porosity upwards through the large‐scale shallowing trend. Separate vug pore types are characterized by relatively low permeabilities (0 to about 10 mD) in spite of the high porosity (up to 20%). The combined occurrence of separate vug and interparticle porosity leads to higher permeabilities (tens of mD). Isolines of porosity, permeability and net/gross follow the contours of the carbonate shoal complex. The highest values of porosity appear more or less at the centre of the shoal, while the highest values of permeability are found at the shoal margins. The distribution of maximum porosity and maximum permeability zones are thus controlled by the cyclic seaward‐stepping and landward‐stepping of the shoal body. The systematic variations in extent, stacking pattern and related petrophysical characteristics of the carbonate shoal bodies may be used for modelling shoal reservoirs in producing oilfields.
Supercritical carbon dioxide extraction of chamomile flowers: extraction efﬁciency, stability, and in‐line inclusion of chamomile–carbon dioxide extract in β ‐cyclodextrin
2004-07-01

Abstract The extraction of chamomile flowers using supercritical carbon dioxide was investigated with respect to extraction efficiency and compared with solvent extraction. The stability of matricine, a sensitive constituent of the essential oil of chamomile, in these extracts was studied during storage at different temperatures over 6 months. Matricine was stable at −30°C. A slight decrease (80–90% recovery) occurred at +5°C, whereas complete decomposition of matricine took place within 3–4 months at room temperature and at +30°C, respectively. An in‐line inclusion of chamomile constituents in β ‐cyclodextrin ( β ‐CD) during the extraction process was assessed and inclusion rates between 40 and 95% were obtained depending on the amount of β ‐CD and the type of chamomile constituent. No further stabilization of matricine in the carbon dioxide extract/ β ‐CD complexes was achieved. High residual water contents in the complexes even after freeze‐drying were identified as accelerating the decomposition. In addition, the extractability of flavonoids, such as apigenin and apigenin‐7‐glucoside, was determined. Apigenin‐7‐glucoside, the more hydrophilic substance, was not extractable with pure carbon dioxide and showed a recovery of 11% using methanol modified carbon dioxide (18%, w/w) at 60°C and 380 bar. Extraction conditions in the two‐phase region of the binary mixture carbon dioxide–methanol (70°C, 100 bar) led to a drastic change in fluid polarity and hence extractability increased to 92–95%. Copyright © 2004 John Wiley &amp; Sons, Ltd.
The corono-apically varying ultrasonic velocity in human hard dental tissues
2004-07-01

The speed of ultrasound at 20 MHz is measured for hard dental tissues inside human teeth. This includes the cementum, for which no data are available. The spatial distribution, extrema, and means of the longitudinal ultrasound velocity (LUV) are determined with an emphasis on the apical thirds and an extended spectrum. Tissue areas are investigated by optical means and by acoustical scanning, in order to compare apical regions-of-interest with the complete mineralized wet porous tissue that lies beneath the enamel cap. The maximal LUV in a single dentin specimen varies from 3903 m/s to 4226 m/s. The dentin’s frequency distribution of LUV at 20 °C exhibits a predominant peak feature comprising several Voigt functions. Introducing standardized relative tooth width portions, the corono-apical decrease in LUV of 21 specimens is approximated by LUV=4224−(257 * ln(y)) along reduced distances in dentin. Abnormal teeth require a higher resolution and an approximate equation of the form LUV=(∑(ai * yi))/(1+∑(bi+1 * y(i+1))). It can be used each time the corono-apical variation has to be quantified in each of the three tissues. Ten coefficients are numerically exemplified. An error evaluation is performed, which denotes errors of 0.2%±1.3% (enamel), −0.1%±1.6% (cementum), and acceptable residual errors for dentin.
Running on empty: sexual co-factors are insufficient to fuel Africa's turbocharged HIV epidemic
2004-07-01

The hypothesis that heterosexual transmission drives sub-Saharan Africa's HIV epidemics requires much faster transmission dynamics in Africa than in the US and Europe, where heterosexual transmission is arguably insufficient to maintain existing levels of HIV prevalence. Initially, experts surmised that Africans had more sexual partners; however, studies of sexual behaviour circa 1990 undermined this assumption. Next, it was supposed that the high burden of bacterial sexually transmitted disease (STD) in Africa explained greater HIV transmission efficiency; however, during the 1990s, community studies in Africa showed that STD had much less than expected impact on HIV transmission. Current attempts to explain HIV as a primarily sexual epidemic in Africa propose multiple factors, including herpes simplex virus type 2, lack of male circumcision, concurrency, and others. These factors also fail for various reasons to account for Africa's HIV epidemics: they are present also in the US and/or Europe; they do not correlate with differences in HIV prevalence across Africa; etc. While behavioural and biological variables influence personal risk for HIV acquisition, the available evidence suggests that they do not differentiate African from US and European epidemics, nor do they determine the differential HIV epidemic trajectories noted across Africa.
A Structurally Available Encephalitogenic Epitope of Myelin Oligodendrocyte Glycoprotein Specifically Induces a Diversified Pathogenic Autoimmune Response
2004-07-01

Abstract Multiple sclerosis is an inflammatory disease of the CNS that involves immune reactivity against myelin oligodendrocyte glycoprotein (MOG), a type I transmembrane protein located at the outer surface of CNS myelin. The epitope MOG92–106 is a DR4-restricted Th cell epitope and a target for demyelinating autoantibodies. In this study, we show that the immune response elicited by immunization with this epitope is qualitatively different from immune responses induced by the well-defined epitopes myelin basic protein (MBP) 84–96 and proteolipid protein (PLP) 139–151. Mice with MOG92–106-, but not with MBP84–96- or PLP139–151-induced experimental autoimmune encephalomyelitis developed extensive B cell reactivity against secondary myelin Ags. These secondary Abs were directed against a set of encephalitogenic peptide Ags derived from MBP and PLP as well as a broad range of epitopes spanning the complete MBP sequence. The observed diversification of the B cell reactivity represents a simultaneous spread toward a broad range of antigenic epitopes and differs markedly from T cell epitope spreading that follows a sequential cascade. The Abs were of the isotypes IgG1 and IgG2b, indicating that endogenously recruited B cells receive help from activated T cells. In sharp contrast, B cell reactivity in MBP84–96- and PLP139–151-induced experimental autoimmune encephalomyelitis was directed against the disease-inducing Ag only. These data provide direct evidence that the nature of the endogenously acquired immune reactivity during organ-specific autoimmunity critically depends on the disease-inducing Ag. They further demonstrate that the epitope MOG92–106 has the specific capacity to induce a widespread autoimmune response.
Oxirene Participation in the Photochemical Wolff Rearrangementa
2004-07-01

Evidence obtained by carbon labelling and carbene-scavenging techniques for the establishment of an α-oxocarbene-oxirene interconversion in the photolysis of acyclic α-diazoketones is summarised. Normalsized alicyclic α-diazoketones and o-quinone diazides react without intervention of the oxirene route, whereas the 12-membered ring system behaves like the acyclic counterparts. The oxirene participation is discussed with reference to stereochemical features of the α-diazoketones and predictions derived from high-level theory. Keywords: diazo carbonyl compounds, 13c-labelling, oxirenes, oxocarbenes, photochemistry, rearrangement mechanisms
Gender-specific risk of perioperative complications in carotid endarterectomy patients with contralateral carotid artery stenosis or occlusion
2004-07-01

Carotid endarterectomy (CEA) has been shown to be effective in stroke prevention in selected patients. Some studies, however, identified gender as an independent risk factor for perioperative CEA complications demonstrating an increased rate of perioperative stroke or death in women. Furthermore, contralateral internal carotid artery (ICA) occlusion has been associated with higher rates of perioperative CEA complications. Therefore, we sought to analyse the gender-specific risk of perioperative CEA complications between patients with or without contralateral ICA stenosis or occlusion. We retrospectively analysed 212 consecutive CEA patients (male = 156, Female = 56) for their gender-specific, perioperative risk of stroke, transient ischemic attack (TIA), restenosis and cardiac complications in the presence (62%) or absence (38%) of a contralateral ICA stenosis/occlusion. In women but not in men, risk of perioperative ischemic events (stroke, TIA) or re-stenosis (p = 0.036) and combined perioperative complications (ischemic events, re-stenosis or cardiac complications; 38.2 % vs. 9.1%; p = 0.028) was significantly increased in the presence of a contralateral ICA stenosis or occlusion. Furthermore, in the presence of a contralateral ICA stenosis/occlusion the number of perioperative ischemic events (p = 0.008) and combined perioperative complications (38.2 % vs. 14.3%; p = 0.006) was significantly higher in female than in male patients. Our study suggests that women with contralateral ICA stenosis or occlusion may have a significantly higher risk for perioperative CEA complications than other subgroups of CEA patients. This risk increase seems to be gender-specific and, if confirmed in larger prospective studies, may influence ICA stenosis therapy in the presence of a contralateral ICA stenosis/occlusion in female patients.
Declining HIV rates in Uganda: due to cleaner needles, not abstinence or condoms
2004-07-01

Public health and political authorities have ascribed the apparent decline in Ugandan HIV or AIDS rates to increased rates of sexual abstinence or condom use. However, what appears to be special about Uganda is that in the middle to late 1980s there was a growing public awareness of health care risks. Given the lack of evidence for transmission of HIV to healthy persons by penile–vaginal intercourse, the improvement in injection safety is the best candidate for declining HIV and AIDS rates.
Iron line spectroscopy of NGC 4593 withXMM-Newton: where is the black hole accretion disc?
2004-07-01

We present an analysis of the 2-10keV XMM-Newton/EPIC-pn spectrum of the Seyfert-1 galaxy NGC4593. Apart from the presence of two narrow emission lines corresponding to the Kalpha lines of cold and hydrogen-like iron, this spectrum possesses a power-law form to within 3-5%. There is a marked lack of spectral features from the relativistic regions of the black hole accretion disk. We show that the data are, however, consistent with the presence of a radiatively-efficient accretion disk extending right down to the radius of marginal stability if it possesses low iron abundance, an appropriately ionized surface, a very high inclination, or a very centrally concentrated emission pattern (as has been observed during the Deep Minimum State of the Seyfert galaxy MCG-6-30-15). Deeper observations of this source are required in order to validate or reject these models.
Enhanced Transgene Expression in Quiescent and Activated Human CD8+T Cells
2004-07-01

The level of expression of retroviral vector-encoded proteins in T cells, decreasing during periods of quiescence, could be an obstacle to their clinical utility. To identify promoter systems that could increase the strength and persistence of transgene expression in primary human CD8(+) T cells, we designed a panel of Moloney retroviral vectors to express a destabilized enhanced green fluorescent protein (d4EGFP) reporter protein (t(1/2) = 4 hr). We found that the promoters phosphoglycerate kinase (Pgk), beta-actin, and long terminal repeat (LTR) produced the highest levels of d4EGFP expression in proliferating T cells, but that expression dramatically declined in quiescent cells with all promoters. To improve gene expression, we examined the effect of the beta-interferon (IFN) scaffold attachment region (SAR). This SAR augmented expression from mammalian promoters in cycling T cells, but had a small effect on maintenance of expression in resting T cells. However, when the SAR was combined with the LTR promoter, it significantly enhanced expression in resting and cycling cells. These data support use of the IFN-beta SAR with the LTR in Moloney retroviral vectors to help sustain gene expression in resting primary human CD8(+) T cells and to enhance gene expression in activated T cells.
Protein Synthesis Inhibition Blocks Consolidation of an Acrobatic Motor Skill
2004-07-01

To investigate whether motor skill learning depends on de novo protein synthesis, adult rats were trained in an acrobatic locomotor task (accelerating rotarod) for 7 d. Animals were systemically injected with cycloheximide (CHX, 0.5 mg/kg, i.p.) 1 h before sessions 1 and 2 or sessions 2 and 3. Control rats received vehicle injections before sessions 1, 2, and 3. Although CHX did not affect improvement of performance within session 1, between-session improvement was impaired. In overtrained animals, comparable injections of CHX had no effect on rotarod performance. These findings suggest that consolidation of motor skills requires protein synthesis.
Transient and phase-locked evoked magnetic fields in response to periodic acoustic signals
2004-07-01

Using whole-head MEG, time course and hemispheric lateralization effects of phase-locked brain responses to complex periodic acoustic signals (stimulus frequency 13, 22, 40, 67, or 111 Hz) were determined based on a dipole analysis approach. Apart from systematic rate-induced changes in amplitude and shape of the transient evoked magnetic fields (M50, M100), phase-locked brain activity emerged, being more pronounced over the right as compared to the left hemisphere. Furthermore, this MEG component showed a consistent phase angle across subjects, indicating active synchronization mechanisms within auditory cortex that operate upon afferent input. Conceivably, these early side-differences in periodicity encoding contribute to or even snowball into hemispheric lateralization effects of higher-order aspects of central-auditory processing such as melody perception.
Chiral symmetry restoration in strange hadronic matter
2004-07-01

The phase transition of chiral symmetry restoration in strange hadronic matter is studied in the chiral SU(3) quark mean field model. When the baryon density is larger than a critical density , the minimal energy density of the system occurs at the point where the effective masses of nucleon, or drop to zero. The physical quantities change discontinuously at this density and the system will be in the phase of chiral symmetry restoration. A rich phase structure of strange hadronic matter with different strangeness fraction is obtained.
Auditory feedback of human EEG for direct brain-computer communication
2004-07-01

The Thought-Translation-Device (TTD) is a Brain-Computer-Interface (BCI) that enables completely paralyzed patients to communicate by the use of their brain signals only. Selfregulation of brain signals (e.g. the slow cortical potentials) is achieved by a feedback training. Visual impairment of these patients asks for an auditory feedback mode. The TTD can be entirely operated by combined listening and mental activity. It provides auditory feedback of brain signals which can operate a verbal spelling interface. The extension POSER allows for sonified orchestral real-time feedback of multiple EEG parameters for the training of self-regulation. The properties of the system are reported and the results of some studies and experiments with auditory feedback are presented.
Thin-Layer Chromatography and Multivariate Data Analysis of Willow Bark Extracts
2004-07-01

In most cases the pharmacological activity of plant extracts is not assigned to single components and often not all active ingredients are known. Approaches other than those considering single compounds only to analyze plant material have proven helpful for a better characterization of extracts in their entirety. In this study extracts of willow bark are analyzed by high-performance thin-layer chromatography (HPTLC) and two different pharmacological tests [the 2,2'-azobis (2-amidinopropane) dihydrochloride reaction and the xanthine/xanthine oxidase reaction] with the help of multivariate data analysis. Described are two models using the results of the chromatographic study of 22 various extracts of willow bark and their pharmacological properties. The chromatographic data are obtained by a special TLC scanner that enables measurement of HPTLC tracks simultaneously in the range of lambda = 200-400 nm. Additionally, the developed models are used to predict the activity of another three extracts of willow bark demonstrating the quality of the model.
Multiple Symmetric Lipomatosis: A Paradigm of Metabolically Innocent Obesity?
2004-07-01

We have recently suggested (1) that patients with multiple symmetric lipomatosis (MSL) may represent a paradigm for metabolically innocent fat accumulation. Harsch and colleagues (2,3) raise some justified words of caution with respect to the generalization of this statement. It is probably true that we cannot make general metabolic inferences on the syndrome of MSL as such based on our rather limited sample size. But this was not our intention, and we welcome the opportunity to clarify our line of argument. The original idea was to present a situation where a substantial increase in body fat mass was not accompanied by decreased insulin sensitivity, which is in much contrast to common belief. ...