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Showing papers by "Technion – Israel Institute of Technology published in 2000"


Journal ArticleDOI
TL;DR: The ubiquitin system plays important roles in the control of numerous processes, including cell-cycle progression, signal transduction, transcriptional regulation, receptor down-regulation, and endocytosis as mentioned in this paper.
Abstract: The selective degradation of many short-lived proteins in eukaryotic cells is carried out by the ubiquitin system. In this pathway, proteins are targeted for degradation by covalent ligation to ubiquitin, a highly conserved small protein. Ubiquitin-mediated degradation of regulatory proteins plays important roles in the control of numerous processes, including cell-cycle progression, signal transduction, transcriptional regulation, receptor down-regulation, and endocytosis. The ubiquitin system has been implicated in the immune response, development, and programmed cell death. Abnormalities in ubiquitin-mediated processes have been shown to cause pathological conditions, including malignant transformation. In this review we discuss recent information on functions and mechanisms of the ubiquitin system. Since the selectivity of protein degradation is determined mainly at the stage of ligation to ubiquitin, special attention is focused on what we know, and would like to know, about the mode of action of ubiquitin-protein ligation systems and about signals in proteins recognized by these systems.

2,177 citations


Journal ArticleDOI
TL;DR: The authors found that when the contract offers money the environment is perceived as monetary, and participants respond in a qualitatively different way in monetary and non-monetary environments in a set of experiments.
Abstract: Economics seems largely based on the assumption that monetary incentives improve performance. By contrast, a large literature in psychology, including a rich tradition of experimental work, claims just the opposite. In this paper we present and discuss a set of experiments designed to test the effect of different monetary compensations on performance. In our experiments we find that whenever money is offered, a larger amount yields a higher performance. It is not true, however, that offering money always induces a higher performance: participants who were offered a small payoff gave a worse performance than those who were offered no compensation at all. These results suggest that the behavior of participants is influenced by their perception of the contract that is offered to them. When the contract offers money the environment is perceived as monetary, and participants respond in a qualitatively different way in monetary and non-monetary environments. In a different set of experiments we test subjects who, acting as principals, have to provide the appropriate incentive to agents. We show that principals do not anticipate the drastic difference in behavior. The vast majority of principals seem to think incorrectly that a larger compensation is unambiguously a better incentive.

2,094 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present the results of a field study in a group of day-care centers that contradicts the deterrence hypothesis that the introduction of a penalty that leaves everything else unchanged will reduce the occurrence of the behavior subject to the fine.
Abstract: The deterrence hypothesis predicts that the introduction of a penalty that leaves everything else unchanged will reduce the occurrence of the behavior subject to the fine. We present the result of a field study in a group of day‐care centers that contradicts this prediction. Parents used to arrive late to collect their children, forcing a teacher to stay after closing time. We introduced a monetary fine for late‐coming parents. As a result, the number of late‐coming parents increased significantly. After the fine was removed no reduction occurred. We argue that penalties are usually introduced into an incomplete contract, social or private. They may change the information that agents have, and therefore the effect on behavior may be opposite of that expected. If this is true, the deterrence hypothesis loses its predictive strength, since the clause “everything else is left unchanged” might be hard to satisfy.

1,721 citations


Journal ArticleDOI
TL;DR: The clonal derivation of two human ES cell lines, H9.1 and H.2, demonstrates the pluripotency of single human ES cells, the maintenance of pluripOTency during an extended period of culture, and the long-term self-renewing properties of cultured human ES Cells.

1,680 citations


Journal ArticleDOI
TL;DR: The Robust Optimization methodology is applied to produce “robust” solutions of the above LPs which are in a sense immuned against uncertainty for the NETLIB problems.
Abstract: Optimal solutions of Linear Programming problems may become severely infeasible if the nominal data is slightly perturbed. We demonstrate this phenomenon by studying 90 LPs from the well-known NETLIB collection. We then apply the Robust Optimization methodology (Ben-Tal and Nemirovski [1–3]; El Ghaoui et al. [5, 6]) to produce “robust” solutions of the above LPs which are in a sense immuned against uncertainty. Surprisingly, for the NETLIB problems these robust solutions nearly lose nothing in optimality.

1,674 citations


Journal ArticleDOI
TL;DR: The ability to induce formation of human embryoid bodies that contain cells of neuronal, hematopoietic and cardiac origins will be useful in studying early human embryonic development as well as in transplantation medicine.
Abstract: Embryonic stem (ES) cells are lines of cells that are isolated from blastocysts. The murine ES cells were demonstrated to be true pluripotent cells as they differentiate into all embryonic lineages. Yet, in vitro differentiation of rhesus ES cells was somewhat inconsistent and disorganized. The recent isolation of human ES cells calls for exploring their pluripotential nature. Human ES cells were grown in suspension to induce their differentiation into embryoid bodies (EBs). The differentiation status of the human ES cells and EBs was analyzed by following the expression pattern of several lineage-specific molecular markers using reverse transcription polymerase chain reaction (RT-PCR) and in situ hybridization. Here we report the induction in vitro of cystic embryoid bodies from human ES cells. Our findings demonstrate induction of expression of cell-specific genes during differentiation of the human ES cells into EBs. In the human EBs, we could show a characteristic regional expression of embryonic markers specific to different cellular lineages, namely, ζ-globin (mesoderm), neurofilament 68Kd (ectoderm), and α-fetoprotein (endoderm). Moreover, we present a synchronously pulsing embryoid body that expresses the myocardium marker α-cardiac actin. In addition, dissociating the embryoid bodies and plating the cells as monolayers results in multiple morphologies, among them cells with neuronal appearance that express neurofilament 68Kd chain. Human ES cells can reproducibly differentiate in vitro into EBs comprising the three embryonic germ layers. The ability to induce formation of human embryoid bodies that contain cells of neuronal, hematopoietic and cardiac origins will be useful in studying early human embryonic development as well as in transplantation medicine.

1,574 citations


Journal ArticleDOI
TL;DR: In this paper, a group-level model of safety climate is proposed to supplement the available organization level model, which is related to supervisory safety practices rather than to company policies and procedures, and a new outcome measure, microaccidents, that refers to behavior-dependent on-the-job minor injuries requiring medical attention.
Abstract: This article presents and tests a group-level model of safety climate to supplement the available organization-level model. Climate perceptions in this case are related to supervisory safety practices rather than to company policies and procedures. The study included 53 work groups in a single manufacturing company. Safety climate perceptions, measured with a newly developed scale, revealed both within-group homogeneity and between-groups variation. Predictive validity was measured with a new outcome measure, microaccidents, that refers to behavior-dependent on-the-job minor injuries requiring medical attention. Climate perceptions significantly predicted microaccident records during the 5-month recording period that followed climate measurement, when the effects of group- and individual-level risk factors were controlled. The study establishes an empirical link between safety climate perceptions and objective injury data.

1,319 citations


Journal ArticleDOI
19 Feb 2000-BMJ
TL;DR: Sleep apnoea syndrome is profoundly associated with hypertension independent of all relevant risk factors, and is a significant predictor of both systolic and diastolic blood pressure after adjustment for age, body mass index, and sex.
Abstract: Objective: To assess whether sleep apnoea syndrome is an independent risk factor for hypertension Design: Population study Setting: Sleep clinic in Toronto Participants: 2677 adults, aged 20-85 years, referred to the sleep clinic with suspected sleep apnoea syndrome Outcome measures: Medical history, demographic data, morning and evening blood pressure, and whole night polysomnography Results: Blood pressure and number of patients with hypertension increased linearly with severity of sleep apnoea, as shown by the apnoea-hypopnoea index Multiple regression analysis of blood pressure levels of all patients not taking antihypertensives showed that apnoea was a significant predictor of both systolic and diastolic blood pressure after adjustment for age, body mass index, and sex Multiple logistic regression showed that each additional apnoeic event per hour of sleep increased the odds of hypertension by about 1%, whereas each 10% decrease in nocturnal oxygen saturation increased the odds by 13% Conclusion: Sleep apnoea syndrome is profoundly associated with hypertension independent of all relevant risk factors

958 citations


Journal ArticleDOI
TL;DR: It is proved that this is also the case for graphs of clique-width at most k, where this complexity measure is associated with hierarchical decompositions of another type, and where logical formulas are no longer allowed to use edge set quantifications.
Abstract: Hierarchical decompositions of graphs are interesting for algorithmic purposes There are several types of hierarchical decompositions Tree decompositions are the best known ones On graphs of tree-width at most k , ie, that have tree decompositions of width at most k , where k is fixed, every decision or optimization problem expressible in monadic second-order logic has a linear algorithm We prove that this is also the case for graphs of clique-width at most k , where this complexity measure is associated with hierarchical decompositions of another type, and where logical formulas are no longer allowed to use edge set quantifications We develop applications to several classes of graphs that include cographs and are, like cographs, defined by forbidding subgraphs with ``too many'' induced paths with four vertices

881 citations


Journal ArticleDOI
TL;DR: Pomegranate juice had potent antiatherogenic effects in healthy humans and in atherosclerotic mice that may be attributable to its antioxidative properties.

847 citations


Journal ArticleDOI
TL;DR: The ubiquitin proteolytic system plays an important role in a broad array of basic cellular processes, including regulation of cell cycle, modulation of the immune and inflammatory responses, control of signal transduction pathways, development and differentiation.
Abstract: The ubiquitin proteolytic system plays an important role in a broad array of basic cellular processes. Among these are regulation of cell cycle, modulation of the immune and inflammatory responses, control of signal transduction pathways, development and differentiation. These complex processes are controlled via specific degradation of a single or a subset of proteins. Degradation of a protein by the ubiquitin system involves two successive steps, conjugation of multiple moieties of ubiquitin and degradation of the tagged protein by the 26S proteasome. An important question concerns the identity of the mechanisms that underlie the high degree of specificity of the system. Substrate recognition is governed by a large family ubiquitin ligases that recognize the substrates, bind them and catalyze/facilitate their interaction with ubiquitin.

Journal ArticleDOI
TL;DR: Crystallographic analysis showed that deletion of the tail of the α3-subunit opens a channel into the proteolytically active interior chamber of the CP, thus derepressing peptide hydrolysis.
Abstract: The core particle (CP) of the yeast proteasome is composed of four heptameric rings of subunits arranged in a hollow, barrel-like structure. We report that the CP is autoinhibited by the N-terminal tails of the outer (α) ring subunits. Crystallographic analysis showed that deletion of the tail of the α3-subunit opens a channel into the proteolytically active interior chamber of the CP, thus derepressing peptide hydrolysis. In the latent state of the particle, the tails prevent substrate entry by imposing topological closure on the CP. Inhibition by the α-subunit tails is relieved upon binding of the regulatory particle to the CP to form the proteasome holoenzyme.

Journal ArticleDOI
TL;DR: The FOG questionnaire that was constructed is highly reliable in assessing freezing of gait, unrelated to falls, in patients with PD.

Journal ArticleDOI
TL;DR: In this paper, the authors explain the cause for photovoltage in nanocrystalline, mesoporous dye-sensitized solar cells, in terms of the separation, recombination, and transport of electronic charge as well as electron energetics.
Abstract: We explain the cause for the photocurrent and photovoltage in nanocrystalline, mesoporous dye-sensitized solar cells, in terms of the separation, recombination, and transport of electronic charge as well as in terms of electron energetics. On the basis of available experimental data, we confirm that the basic cause for the photovoltage is the change in the electron concentration in the nanocrystalline electron conductor that results from photoinduced charge injection from the dye. The maximum photovoltage is given by the difference in electron energies between the redox level and the bottom of the electron conductor's conduction band, rather than by any difference in electrical potential in the cell, in the dark. Charge separation occurs because of the energetic and entropic driving forces that exist at the dye/electron conductor interface, with charge transport aided by such driving forces at the electron conductor/contact interface. The mesoporosity and nanocrystallinity of the semiconductor are importa...

Journal ArticleDOI
01 Aug 2000-Brain
TL;DR: The way in which cutaneous allodynia develops by measuring the pain thresholds in the head and forearms bilaterally at several time points during a migraine attack in a 42-year-old male is studied and calls for early use of anti-migraine drugs that target peripheral nociceptors, before the development of central sensitization.
Abstract: Recently, we showed that most migraine patients exhibit cutaneous allodynia inside and outside their pain-referred areas when examined during a fully developed migraine attack. In this report, we studied the way in which cutaneous allodynia develops by measuring the pain thresholds in the head and forearms bilaterally at several time points during a migraine attack in a 42-year-old male. Prior to the headache, he experienced visual, sensory, motor and speech aura. During the headache, he experienced photo-, phono- and odour-phobia, nausea and vomiting, worsening of the headache by coughing or moving his head, and cutaneous pain when shaving, combing his hair or touching his scalp. Comparisons between his pain thresholds in the absence of migraine and at 1, 2 and 4 h after the onset of migraine revealed the following. (i) After 1 h, mechanical and cold allodynia started to develop in the ipsilateral head but not in any other site. (ii) After 2 h, this allodynia increased on the ipsilateral head and spread to the contralateral head and ipsilateral forearm. (iii) After 4 h, heat allodynia was also detected while mechanical and cold allodynia continued to increase. These clinical observations suggest the following sequence of events along the trigeminovascular pain pathway of this patient. (i) A few minutes after the initial activation of his peripheral nociceptors, they became sensitized; this sensitization can mediate the symptoms of intracranial hypersensitivity. (ii) The barrage of impulses that came from the peripheral nociceptors activated second-order neurons and initiated their sensitization; this sensitization can mediate the development of cutaneous allodynia on the ipsilateral head. (iii) The barrage of impulses that came from the sensitized second-order neurons activated and eventually sensitized third-order neurons; this sensitization can mediate the development of cutaneous allodynia on the contralateral head and ipsilateral forearm at the 2-h point, over 1 h after the appearance of allodynia on the ipsilateral head. This interpretation calls for an early use of anti-migraine drugs that target peripheral nociceptors, before the development of central sensitization. If central sensitization develops, the therapeutic rationale is to suppress it. Because currently available drugs that aim to suppress central sensitization are ineffective, this study stresses the need to develop them for the treatment of migraine.

01 Jan 2000
TL;DR: These spectral methods may be used for compression and progressive transmission of 3D content, and are shown to be vastly superior to existing methods using spatial techniques, if slight loss can be tolerated.
Abstract: We show how spectral methods may be applied to 3D mesh data to obtain compact representations. This is achieved by projecting the mesh geometry onto an orthonormal basis derived from the mesh topology. To reduce complexity, the mesh is partitioned into a number of balanced submeshes with minimal interaction, each of which are compressed independently. Our methods may be used for compression and progressive transmission of 3D content, and are shown to be vastly superior to existing methods using spatial techniques, if slight loss can be tolerated.

Journal ArticleDOI
16 Mar 2000-Nature
TL;DR: It is shown that co-activation of clustered neighbouring basal inputs initiated local dendritic spikes, which resulted in a 5.9 ± 1.5 mV change at the soma that amplified the somatic voltage response by 226 ± 46%.
Abstract: Basal dendrites are a major target for synaptic inputs innervating cortical pyramidal neurons At present little is known about signal processing in these fine dendrites Here we show that coactivation of clustered neighbouring basal inputs initiated local dendritic spikes, which resulted in a 59 +/- 15 mV (peak) and 644 +/- 198 ms (half-width) cable-filtered voltage change at the soma that amplified the somatic voltage response by 226 +/- 46% These spikes were accompanied by large calcium transients restricted to the activated dendritic segment In contrast to conventional sodium or calcium spikes, these spikes were mediated mostly by NMDA (N-methyl-D-aspartate) receptor channels, which contributed at least 80% of the total charge The ionic mechanism of these NMDA spikes may allow 'dynamic spike-initiation zones', set by the spatial distribution of glutamate pre-bound to NMDA receptors, which in turn would depend on recent and ongoing activity in the cortical network In addition, NMDA spikes may serve as a powerful mechanism for modification of the cortical network by inducing long-term strengthening of co-activated neighbouring inputs

Journal ArticleDOI
TL;DR: In this article, the cooling effect of small urban green wooded sites of various geometric configurations in summer is studied experimentally at 11 different green sites in the Tel-Aviv urban complex during the period July-August 1996.

Proceedings ArticleDOI
01 Jul 2000
TL;DR: In this paper, spectral methods are applied to 3D mesh data to obtain compact representations, which is achieved by projecting the mesh geometry onto an orthonormal basis derived from the mesh topology.
Abstract: We show how spectral methods may be applied to 3D mesh data to obtain compact representations. This is achieved by projecting the mesh geometry onto an orthonormal basis derived from the mesh topology. To reduce complexity, the mesh is partitioned into a number of balanced submeshes with minimal interaction, each of which are compressed independently. Our methods may be used for compression and progressive transmission of 3D content, and are shown to be vastly superior to existing methods using spatial techniques, if slight loss can be tolerated.

Journal ArticleDOI
01 Jun 2000
TL;DR: SALSA, a new stochastic approach for link structure analysis, which examines random walks on graphs derived from the link structure, is presented and it is proved that SALSA is equivalent to a weighted in-degree analysis of the link-structure of World Wide Web subgraphs, making it computationally more efficient than the mutual reinforcement approach.
Abstract: Today, when searching for information on the World Wide Web, one usually performs a query through a term-based search engine. These engines return, as the query's result, a list of Web sites whose contents match the query. For broad topic queries, such searches often result in a huge set of retrieved documents, many of which are irrelevant to the user. However, much information is contained in the link-structure of the World Wide Web. Information such as which pages are linked to others can be used to augment search algorithms. In this context, Jon Kleinberg introduced the notion of two distinct types of Web sites: hubs and authorities . Kleinberg argued that hubs and authorities exhibit a mutually reinforcing relationship : a good hub will point to many authorities, and a good authority will be pointed at by many hubs. In light of this, he devised an algorithm aimed at finding authoritative sites. We present SALSA, a new stochastic approach for link structure analysis, which examines random walks on graphs derived from the link structure. We show that both SALSA and Kleinberg's mutual reinforcement approach employ the same meta-algorithm. We then prove that SALSA is equivalent to a weighted in-degree analysis of the link-structure of World Wide Web subgraphs, making it computationally more efficient than the mutual reinforcement approach. We compare the results of applying SALSA to the results derived through Kleinberg's approach. These comparisons reveal a topological phenomenon called the TKC effect (Tightly Knit Community) which, in certain cases, prevents the mutual reinforcement approach from identifying meaningful authorities.

Journal ArticleDOI
TL;DR: This work considers quantum cryptographic schemes where the carriers of information are 3-state particles and one protocol uses four mutually unbiased bases and appears to provide better security than obtainable with 2-state carriers.
Abstract: We consider quantum cryptographic schemes where the carriers of information are 3-state particles. One protocol uses four mutually unbiased bases and appears to provide better security than obtainable with 2-state carriers. Another possible method allows quantum states to belong to more than one basis. Security is not better, but many curious features arise.

Journal ArticleDOI
TL;DR: It is concluded that PON1 may be antiatherogenic because it hydrolyzes lipid peroxides in human atherosclerotic lesions and demonstrates esterase- like and peroxidase-like activities.
Abstract: Background—Human serum paraoxonase (PON1) exists in two polymorphic forms: one that differs in the amino acid at position 192 (glutamine and arginine, Q and R, respectively) and the second one that differs in the amino acid at position 55 (methionine and leucine, M and L, respectively). PON1 protects LDL from oxidation, and during LDL oxidation, PON1 is inactivated. Methods and Results—The present study compared PON1 isoforms Q and R for their effect on lipid peroxide content in human coronary and carotid lesions. After 24 hours of incubation with PON1Q or PON1R (10 arylesterase units/mL), lipid peroxides content in both coronary and carotid lesion homogenates (0.1 g/mL) was reduced up to 27% and 16%, respectively. The above incubation was associated with inactivation of PON1Q and PON1R by 15% and 45%, respectively. Lesion cholesteryl linoleate hydroperoxides and cholesteryl linoleate hydroxides were hydrolyzed by PON1 to yield linoleic acid hydroperoxides and linoleic acid hydroxides. Furthermore, lesion...

Journal ArticleDOI
TL;DR: The theory of metric regularity is an extension of two classical results: the Lyusternik tangent space theorem and the Graves surjection theorem as mentioned in this paper, and it was also well understood that the phenomena behind the results are of metric origin, not connected with any linear structure.
Abstract: The theory of metric regularity is an extension of two classical results: the Lyusternik tangent space theorem and the Graves surjection theorem. Developments in non-smooth analysis in the 1980s and 1990s paved the way for a number of far-reaching extensions of these results. It was also well understood that the phenomena behind the results are of metric origin, not connected with any linear structure. At the same time it became clear that some basic hypotheses of the subdifferential calculus are closely connected with the metric regularity of certain set-valued maps. The survey is devoted to the metric theory of metric regularity and its connection with subdifferential calculus in Banach spaces.

Journal ArticleDOI
TL;DR: It is reported that human umbilical vein-derived endothelial cells express the a17 and a22 splice forms of the np-2 receptor, and it is possible that VEGF-inducednp-2-mediated signaling will take place only in the presence of other V EGF receptors such as VEGFs receptor-1 or VEGf receptor-2.

Proceedings ArticleDOI
17 Oct 2000
TL;DR: It is proved that essentially all reasonable approximations or heuristics for combinatorial auctions as well as a wide class of cost minimization problems yield non-truthful VCG-based mechanisms and proposes a general method for circumventing the above problem.
Abstract: A major achievement of mechanism design theory is a general method for the construction of truthful mechanisms called VCG (Vickrey, Clarke, Groves). When applying this method to complex problems such as combinatorial auctions, a difficulty arises: VCG mechanisms are required to compute optimal outcomes and are, therefore, computationally infeasible. However, if the optimal outcome is replaced by the results of a sub-optimal algorithm, the resulting mechanism (termed VCG-based) is no longer necessarily truthful. The first part of this paper studies this phenomenon in depth and shows that it is near universal. Specifically, we prove that essentially all reasonable approximations or heuristics for combinatorial auctions as well as a wide class of cost minimization problems yield non-truthful VCG-based mechanisms. We generalize these results for affine maximizers. The second part of this paper proposes a general method for circumventing the above problem. We introduce a modification of VCG-based mechanisms in which the agents are given a chance to improve the output of the underlying algorithm. When the agents behave truthfully, the welfare obtained by the mechanism is at least as good as the one obtained by the algorithm’s output. We provide a strong rationale for truth-telling behavior. Our method satisfies individual rationality as well.

Journal ArticleDOI
TL;DR: In this paper, the radio loudness bimodality is strongly related to the black hole mass (M_BH), and the properties of various types of AGN may be largely set by three basic parameters, including M_bH, L/L_Eddington, and inclination angle.
Abstract: The distribution of radio to optical fluxes in AGN is bimodal. The physical origin for this bimodality is not understood. In this Letter I describe observational evidence, based on the Boroson & Green PG quasar sample, that the radio loudness bimodality is strongly related to the black hole mass (M_BH). Nearly all PG quasars with M_BH>10^9M_sun are radio loud, while quasars with M_BH<3x10^8M_sun are practically all radio quiet. This result is consistent with the dependence of quasar host galaxy morphology on radio loudness. There is no simple physical explanation for this result, but it may provide a clue on how jets are formed near massive black holes. The radio loudness--black hole mass relationship suggests that the properties of various types of AGN may be largely set by three basic parameters, M_BH, L/L_Eddington, and inclination angle.

Journal ArticleDOI
TL;DR: In this article, the authors stress the fact that quantum theory does not need an interpretation other than being an algorithm for computing probabilities associated with macroscopic phenomena and measurements, and the wave function is not objective entity, it only gives the evolution of our probabilities for the outcomes potential experiments.
Abstract: Purpose of this article is to stress the fact that Quantum Theory does not need an interpretation other than being an algorithm for computing probabilities associated with macroscopic phenomena and measurements. It does not ''describ'' reality, and the wave function is not objective entity, it only gives the evolution of our probabilities for the outcomes potential experiments. (AIP) (c)

Journal ArticleDOI
TL;DR: In this paper, an analysis of C IV absorption in the 55 Boroson & Green QSOs with available C IV data was conducted, and the authors found a remarkably strong correlation between?ox and the C IV equivalent width.
Abstract: Recent studies of quasi-stellar objects (QSOs) with ROSAT suggest the existence of a significant population of soft X-ray weak QSOs (SXW QSOs) where the soft X-ray flux is ~10-30 times smaller than in typical QSOs. Why are these QSOs soft X-ray weak, and what is their relationship to broad absorption line QSOs (BAL QSOs) and X-ray warm absorber QSOs? As a first step in a systematic study of these objects, we establish a well-defined sample of SXW QSOs that includes all ?ox ? -2 QSOs from the Boroson & Green sample of 87 Bright Quasar Survey QSOs. SXW?QSOs comprise ?11% of this optically selected QSO sample, and we find soft X-ray weakness in both radio-quiet and radio-loud QSOs. From an analysis of C IV absorption in the 55 Boroson & Green QSOs with available C IV data, we find a remarkably strong correlation between ?ox and the C IV absorption equivalent width. This correlation suggests that absorption is the primary cause of soft X-ray weakness in QSOs, and it reveals a continuum of absorption properties connecting unabsorbed QSOs, X-ray warm absorber QSOs, SXW QSOs, and BAL QSOs. Many of our SXW QSOs have ultraviolet absorption that is intermediate in strength between that of X-ray warm absorber QSOs and that of BAL QSOs, and their X-ray absorption is also likely to be of intermediate strength. From a practical point of view, our correlation demonstrates that selection by soft X-ray weakness is an effective (80% successful) and observationally inexpensive way to find low-redshift QSOs with strong and interesting ultraviolet absorption. We have also identified several notable differences between the optical emission-line properties of SXW QSOs and those of the other Boroson & Green QSOs. SXW?QSOs show systematically low [O III] luminosities and equivalent widths as well as distinctive H? line profiles. They tend to lie toward the weak [O III] end of Boroson & Green eigenvector 1, as do many low-ionization BAL QSOs. Unabsorbed Seyfert galaxies and QSOs with similar values of eigenvector 1 have been suggested to have extreme values of a primary physical parameter, perhaps mass accretion rate relative to the Eddington rate (/Edd). If these suggestions are correct, it is likely that SXW QSOs also tend to have generally high values of /Edd. Finally, we present and discuss correlations between ?ox and other QSO observables after removal of the SXW QSOs.

Journal ArticleDOI
TL;DR: Biotinylated dextran amines (BDA) are highly sensitive tools for anterograde and retrograde pathway tracing studies of the nervous system and can, therefore, be readily used in ultrastructural studies.

Journal ArticleDOI
TL;DR: It is concluded that dietary consumption of ginger extract by E(0) mice significantly attenuates the development of atherosclerotic lesions and is associated with a significant reduction in plasma and LDL cholesterol levels and asignificant reduction in the LDL basal oxidative state.
Abstract: Oxidative modification of LDL is thought to play a key role in the pathogenesis of atherosclerosis. Consumption of nutrients rich in phenolic antioxidants has been shown to be associated with attenuation of development of atherosclerosis. This study was undertaken to investigate the ex vivo effect of standardized ginger extract on the development of atherosclerosis in apolipoprotein E-deficient (E(0)) mice, in relation to plasma cholesterol levels and the resistance of their LDL to oxidation and aggregation. E(0) mice (n = 60; 6-wk-old) were divided into three groups of 20 and fed for 10 wk via their drinking water with the following: group i) placebo (control group), 1.1% alcohol and water (11 mL of alcohol in 1 L of water); group ii) 25 microg of ginger extract/d in 1.1% alcohol and water and group iii) 250 microg of ginger extract/day in 1.1% alcohol and water. Aortic atherosclerotic lesion areas were reduced 44% (P<0.01) in mice that consumed 250 microg of ginger extract/day. Consumption of 250 microg of ginger extract/day resulted in reductions (P<0.01) in plasma triglycerides and cholesterol (by 27 and 29%, respectively), in VLDL (by 36 and 53%, respectively) and in LDL (by 58 and 33%, respectively). These results were associated with a 76% reduction in cellular cholesterol biosynthesis rate in peritoneal macrophages derived from the E(0) mice that consumed the high dose of ginger extract for 10 wk (P<0.01). Furthermore, peritoneal macrophages harvested from E(0) mice after consumption of 25 or 250 microg of ginger extract/day had a lower (P<0.01) capacity to oxidize LDL (by 45 and by 60%, respectively), and to take up and degrade oxidized LDL (by 43 and 47%, respectively). Consumption of 250 microg of ginger extract/day also reduced (P<0.01) the basal level of LDL-associated lipid peroxides by 62%. In parallel, a 33% inhibition (P<0.01) in LDL aggregation (induced by vortexing) was obtained in mice fed ginger extract. We conclude that dietary consumption of ginger extract by E(0) mice significantly attenuates the development of atherosclerotic lesions. This antiatherogenic effect is associated with a significant reduction in plasma and LDL cholesterol levels and a significant reduction in the LDL basal oxidative state, as well as their susceptibility to oxidation and aggregation.