Journal articles on the topic 'Speculative interference'
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1
Yang, Lei, Yu Dai, and Bin Zhang. "Optimized Speculative Execution to Improve Performance of MapReduce Jobs on Virtualized Computing Environment." Mathematical Problems in Engineering 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/2724531.
Abstract:
Recently, virtualization has become more and more important in the cloud computing to support efficient flexible resource provisioning. However, the performance interference among virtual machines may affect the efficiency of the resource provisioning. In a virtualized environment, where multiple MapReduce applications are deployed, the performance interference can also affect the performance of the Map and Reduce tasks resulting in the performance degradation of the MapReduce jobs. Then, in order to ensure the performance of the MapReduce jobs, a framework for scheduling the MapReduce jobs with the consideration of the performance interference among the virtual machines is proposed. The core of the framework is to identify the straggler tasks in a job and back up these tasks to make the backed up one overtake the original tasks in order to reduce the overall response time of the job. Then, to identify the straggler task, this paper uses a method for predicting the performance interference degree. A method for scheduling the backing-up tasks is presented. To verify the effectiveness of our framework, a set of experiments are done. The experiments show that the proposed framework has better performance in the virtual cluster compared with the current speculative execution framework.
2
V. Vygodin, A. "Effects of Central Banks' Interference on Speculative Build-up in the Foreign Exchange Markets." International Journal of Applied Economics and Finance 9, no. 1 (January 1, 2015): 1–14. http://dx.doi.org/10.3923/ijaef.2015.1.14.
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Heller, Henry. "Bankers, Finance Capital and the French Revolutionary Terror (1791–94)." Historical Materialism 22, no. 3-4 (December 2, 2014): 172–216. http://dx.doi.org/10.1163/1569206x-12341377.
Abstract:
This article argues that popular revolution was closely tied to the establishment of capitalism. Contrary to the revisionist George V. Taylor’s view that the Revolution had nothing to do with the advance of capitalism because financial and productive capital were divided from one another, this article contends that the Revolution played a critical role in tying them together. Prior to the Revolution financiers began to make limited investments in wholesale trade, manufacturing and mining. But during the revolutionary crisis the sans-culottes pushed the Jacobins to create a national money and to curb speculation in order to foster production and exchange and reduce unemployment. With speculative activity blocked by popular resistance and state interference, bankers and other capitalists increasingly turned to productive investments and forged a link between financial and productive capital which proved crucial to further capitalist accumulation.
4
Fragakis, Nikolaos, Gabriele Vicedomini, and Carlo Pappone. "Endurance Sport Activity and Risk of Atrial Fibrillation – Epidemiology, Proposed Mechanisms and Management." Arrhythmia & Electrophysiology Review 3, no. 1 (April 30, 2014): 15–19. http://dx.doi.org/10.15420/aer.2011.3.1.15.
Abstract:
There is evidence for a higher prevalence of atrial fibrillation (AF) in athletes engaged in long-term endurance sports training compared with the general population. Although atrial anatomic adaptations, alterations in autonomic nervous system, chronic systemic inflammation and fibrosis have been proposed as potential mechanisms, they remain speculative. Medical therapy with long-term antiarrhythmic agents or pill in the pocket medications is hampered by limitations, such as sports eligibility and interference with exercise tolerance. AF ablation represents a valid therapeutic option with results similar to these achieved in other patients. Nevertheless, further clinical trials are needed to confirm whether endurance sport practice affects the maintenance of sinus rhythm following catheter ablation of AF.
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Fragakis, Nikolaos, Gabriele Vicedomini, and Carlo Pappone. "Endurance Sport Activity and Risk of Atrial Fibrillation – Epidemiology, Proposed Mechanisms and Management." Arrhythmia & Electrophysiology Review 3, no. 1 (2011): 15. http://dx.doi.org/10.15420/articles/endurance-sport-activity-and-risk-atrial-fibrillation-epidemiology-proposed-mechanisms-and.
Abstract:
There is evidence for a higher prevalence of atrial fibrillation (AF) in athletes engaged in long-term endurance sports training compared with the general population. Although atrial anatomic adaptations, alterations in autonomic nervous system, chronic systemic inflammation and fibrosis have been proposed as potential mechanisms, they remain speculative. Medical therapy with long-term antiarrhythmic agents or pill in the pocket medications is hampered by limitations, such as sports eligibility and interference with exercise tolerance. AF ablation represents a valid therapeutic option with results similar to these achieved in other patients. Nevertheless, further clinical trials are needed to confirm whether endurance sport practice affects the maintenance of sinus rhythm following catheter ablation of AF.
6
GAMBLE, SUSAN. "AN APPEALING CASE OF SPECTRA: PHOTOGRAPHS ON DISPLAY AT THE ROYAL SOCIETY, LONDON 1891." Nuncius 17, no. 2 (2002): 635–51. http://dx.doi.org/10.1163/182539102x00153.
Abstract:
Abstracttitle SUMMARY /title This essay compares the visual appearance and reception of two differing exhibits of spectroscopic data at the Royal Society's Conversazione of 1891; it is speculative in that there is no photographic record of the objects that were displayed. The authors Gabriel Lippmann (1845-1921) and Charles Piazzi Smyth (1819-1900) represent two different approaches both to astrophysics and photography current at the end of the nineteenth-century. I examine the importance of spectra as 'scientific' and aesthetic images. In particular, I explore how Gabriel Lippmann used the image of a spectrum to promote his invention of an instant 'interference' colour photography to a scientific milieu as well as a popular audience - eventually winning a Nobel Prize for this process in 1908.
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Loska, Krzysztof. "Posthumanistyczne echa, apokaliptyczne tony i zwierzęce odgłosy w filmach Bonga Joon-ho." Images. The International Journal of European Film, Performing Arts and Audiovisual Communication 28, no. 37 (March 31, 2021): 151–66. http://dx.doi.org/10.14746/i.2020.37.09.
Abstract:
The subject of the analysis in this article are three films by Bong Joon-ho: The Host (2006), Snowpiercer (2013) and Okja (2017), considered from the posthumanist perspective. A starting point is Donna Haraway’s suggestion that science-fiction stories should be treated as a tool for speculative thinking. Then, I point to the way the Korean film director demonstrates his critical reflection on the effects of climate change, deepening economic inequalities, the impact of global capitalism and the biopolitical model of the governance. The main aim is to seek out the possible strategies of resistance which enable humans to change their attitude to other species (Okja) and to ask a question about the scope of human freedom, the effects of our interference in the functioning of the biosphere (Snowpiercer) and the results of genetic modifications of animals.
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Everson, Carol A. "Clinical assessment of blood leukocytes, serum cytokines, and serum immunoglobulins as responses to sleep deprivation in laboratory rats." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 289, no. 4 (October 2005): R1054—R1063. http://dx.doi.org/10.1152/ajpregu.00021.2005.
Abstract:
The specific systems and mechanisms affected by sleep deprivation that may perpetuate disease processes in humans still are speculative. In laboratory rats, prolonged sleep deprivation induces a state marked by abnormal control over indigenous bacteria that results in transient infections of internal tissues and eventual lethal septicemia. The present studies investigated changes in blood, serum, and bone marrow parameters that may provide diagnostic clues to immunopathology. Prolonged sleep deprivation was produced in rats by the disk-over-water method, a well-established and selective means that does not interfere with normal waking behaviors. Measurements included bone and blood differential white blood cell counts, multiple serum cytokines and chemokines, several major Ig classes and subclasses, and serum endotoxin concentrations. The results indicated mild, regenerative neutrophilia in sleep-deprived rats, initially accompanied by immature neutrophils and later by monocytosis. The corresponding serum cytokine profile revealed an evolving proinflammatory state, particularly by high incidence of interleukin-1β, implicating mononuclear phagocytes and resident tissue cells as main intermediary sources. In addition, multiple serum Ig classes were increased by sleep deprivation without experimental administration of an exogenous antigen. Despite this immune activation, there was failure to eradicate invading bacteria and toxins, suggesting competing anti-inflammatory processes or interference with immune effector functions during sleep deprivation. Nearly all of the immune-related events that emerged as responses to sleep deprivation have been implicated as etiological or provocative factors in other disease processes and may provide means by which sleep deprivation as a risk factor in disease may become understood.
9
Sonah, Humira, Rupesh K. Deshmukh, and Anil S. Kotasthane. "Fungicidal Interference during Infection Related Developmental Stages in Magnaporthe grisea." International Journal of Phytopathology 1, no. 1 (December 15, 2012): 49–55. http://dx.doi.org/10.33687/phytopath.001.01.0015.
Abstract:
Rice blast, a serious epidemic disease that limits grain yield worldwide is caused by fungal pathogen Magnaporthe grisea. The present investigation was carried out to identify the probable avenues of interference by different fungicides during the critical stages of infection related morphogenesis of M. grisea. Effect of six fungicides at different stages of infection related morphogenesis showed variable results like interference in conidial germination, distortion of surface structure of the spores, interference in the germ tube elongation, interference in the transfer of the cell contents from spore to appresorrium, deformity in appressorial dome, interference in the melanin deposition. We speculate the critical stages at which these fungicides may interfere. The activity of immunosuppressive drug cyclosporin A (CsA) which is a potential antifungal agent was equated with all the fungicides used. We hypothesize that the exposure of the M. grisea spore to the fungicide may lead to the formation of a cyclophilin CYP1-fungicide complex, which inactivates calcineurin and prevents calcium/ calmodulin-dependent protein phosphatase signaling and is therefore one of the target of fungicidal interference. An understanding of how fungal pathogens break the protective barrier that comprise the surface of the host plant as well as precise identification of avenues of fungicidal interference during infection related development in M. grisea will lead to novel approach for controlling plant diseases.
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Masson, M., M. Kostine, T. Barnetche, M. E. Truchetet, C. Richez, and T. Schaeverbeke. "AB0661 CO-MEDICATIONS MAY ALTER THE RESPONSE TO TNF-INHIBITORS IN SPONDYLOARTHRITIS PATIENTS: A PHARMACOMICROBIOMIC EFFECT?" Annals of the Rheumatic Diseases 79, Suppl 1 (June 2020): 1625.2–1626. http://dx.doi.org/10.1136/annrheumdis-2020-eular.3823.
Abstract:
Background:The reason why some spondyloarthritis (SA) patients fail to respond to TNF inhibitors (TNF-i) remains unclear. Recently, it has been shown in cancer immunotherapy that the therapeutic response may be strongly altered by co-medication with drugs interfering with the gut microbiota, such as antibiotics, proton pump inhibitors (PPI), non-steroidal anti-inflammatory drugs (NSAIDs), psychotropic or antidiabetic drugs.Objectives:Considering the potential role of the gut microbiota in the pathophysiology of SA as in the therapeutic response, the aim was to study the influence of co-medications known to interfere with the microbiota with the therapeutic response to TNF-i in SA patients.Methods:We retrospectively reviewed the charts of all patients treated in our department with a first TNF-i from 2009 to 2018. Data collected were demographic information, HLA-B27 status, disease characteristics… Patients were classified as responder (R) or non-responder (NR) according to the BASDAI (< 40/100) value at M6 or to the clinician judgment (when BASDAI was not available). Regarding co-medications, we collected all drugs known to interfere with the gut microbiota that were administered 1 month before and during the first 3 months of the TNF-i treatment. We only considered drugs given to more than 5% of patients. Quantitative data were expressed as mean ± standard deviation, and qualitative variables as percentages. Univariate and multivariate analyses were performed to evaluate the relationship between co-medications and TNF-i. All analyses were computed on STATA 13.1 software with a statistically significant threshold of 0.05.Results:We included 188 patients suffering from ankylosing spondylitis (n=89) or peripheral SA (n=99). They were 68 women and 120 men, mean aged 46.6 ± 13; 53% were B27 positive. TNF-i were infliximab (19%), etanercept (44%), adalimumab (34%) golimumab (2%), certolizumab (1%), combined with MTX in 51 patients. 135 patients (72%) were R and 53 (28%) NR. In univariate analysis, 59.1% of patients who received NSAIDs were R, compared to 88.2% of patients not treated with NSAIDs (p< 0.0001); 42.2% of patients receiving PPIs were R compared to 86.3% of patients PPI free (p< 0.0001); 55.8% of patients who were given antibiotics were R, compared to 75.7% of patients who did not (p=0,02); 27.8% of patients treated with psychotropic drugs were R, compared to 75.9% of patients not receiving such treatment (p< 0.0001) (Figure 1). Differences were not statistically significant for corticosteroids, MTX, angiotensin-converting enzyme inhibitors and statins. Although 91% of patients taken PPIs were also given NSAIDs, NSAIDs, PPIs and antibiotics intake were considered as independent factors associated with TNF-i failure in multivariate analysis.Conclusion:Co-medication with NSAIDs, PPIs, antibiotics and psychotropic drugs were significantly associated with a decreased chance to respond to TNF-i. The hypothesis that this effect is due to their interference with the gut microbiota is only speculative but, regardless the reason of this interaction, clinician should be aware of the potential negative effect of these co-medication on TNF-i.Figure 1.Disclosure of Interests:Maéva Masson: None declared, Marie Kostine: None declared, Thomas Barnetche: None declared, Marie-Elise Truchetet: None declared, Christophe Richez Consultant of: Abbvie, Amgen, Mylan, Pfizer, Sandoz and UCB., Thierry Schaeverbeke: None declared
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Lin, Fanqiang, Kecheng Chen, Xuben Wang, Hui Cao, Danlei Chen, and Fanzeng Chen. "Denoising stacked autoencoders for transient electromagnetic signal denoising." Nonlinear Processes in Geophysics 26, no. 1 (March 1, 2019): 13–23. http://dx.doi.org/10.5194/npg-26-13-2019.
Abstract:
Abstract. The transient electromagnetic method (TEM) is extremely important in geophysics. However, the secondary field signal (SFS) in the TEM received by coil is easily disturbed by random noise, sensor noise and man-made noise, which results in the difficulty in detecting deep geological information. To reduce the noise interference and detect deep geological information, we apply autoencoders, which make up an unsupervised learning model in deep learning, on the basis of the analysis of the characteristics of the SFS to denoise the SFS. We introduce the SFSDSA (secondary field signal denoising stacked autoencoders) model based on deep neural networks of feature extraction and denoising. SFSDSA maps the signal points of the noise interference to the high-probability points with a clean signal as reference according to the deep characteristics of the signal, so as to realize the signal denoising and reduce noise interference. The method is validated by the measured data comparison, and the comparison results show that the noise reduction method can (i) effectively reduce the noise of the SFS in contrast with the Kalman, principal component analysis (PCA) and wavelet transform methods and (ii) strongly support the speculation of deeper underground features.
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Masson, M., M. Kostine, T. Barnetche, A. Saraux, A. Ruyssen-Witrand, T. Thomas, D. Wendling, M. E. Truchetet, C. Richez, and T. Schaeverbeke. "AB0469 PROTON PUMP INHIBITORS MAY IMPAIR RESPONSE TO TNF-INHIBITORS IN SPONDYLOARTHRITIS PATIENTS." Annals of the Rheumatic Diseases 80, Suppl 1 (May 19, 2021): 1261.2–1262. http://dx.doi.org/10.1136/annrheumdis-2021-eular.1716.
Abstract:
Background:Considering the potential role of the gut microbiota in the pathophysiology of spondyloarthritis (SpA) as in the therapeutic response to biologics (1), we evaluated the hypothesis that co-medications known to interfere with the gut microbiota could impair the therapeutic response to TNF-inhibitors (TNF-i) in SpA patients. This was first suggested by the results of a retrospective cohort showing that a co-medication with proton pump inhibitors (PPIs), non-steroidal anti-inflammatory drugs (NSAIDs) or antibiotics was significantly associated with a decreased chance to respond to a first TNF-I, independently of each other (2).Objectives:To validate in a replication cohort the potential negative association between therapeutic response to TNF-i and co-medication with commonly used drugs.Methods:Demographic information and disease characteristics were retrospectively collected. Patients were classified as responder (R) or non-responder (NR) according to the BASDAI (< 40/100) value at month 6 or to the clinician judgment (when BASDAI was not available). We collected all drugs known to interfere with the gut microbiota that were administered 1 month before and during the first 3 months of the TNF-i treatment. We only considered drugs given to more than 5% of patients. Univariate and multivariate analyses were performed to evaluate the relationship between co-medications, predictors of response known from literature and TNF-i response. All analyses were computed on STATA 13.1 with a statistically significant threshold of 0.05.Results:We included from 4 different centres 185 patients having axial SpA with radiographic or magnetic sacroiliitis in 75% and 73% of cases, respectively. One third of them had peripheral involvement. 73% were B27 positive. TNF-i administrated were infliximab (8%), etanercept (22%), adalimumab (44%) golimumab (19%), certolizumab (7%). 127 patients (69%) were considered as R. 59.4% of patients who received NSAIDs were R, compared to 81% not treated with NSAIDs (p< 0.0001). 43,3% of patients receiving PPIs were R compared to 83% of patients PPI free (p< 0.0001). Differences were not significant for antibiotics, methotrexate (MTX), psychotic drugs and corticosteroids. Considering known predictors of response, a magnetic sacroiliitis and the age at TNF-i initiation were significantly associated with a higher proportion of R patients (p=0.048 and 0.018 respectively). In multivariate analysis, PPIs intake remained associated with a poorer response to a first TNF-i (p<0.001), even though 88% of patients exposed to PPIs received also NSAIDs.Univariate analysisMultivariate analysisOdd Ratio (95% Confidence Interval)Gender1.43 (0.76; 2.72)Disease duration1.02 (0.99; 1.06)Age at TNF-I initiation0.97 (0.95; 0.995) 0.97 (0.94; 0.999)Magnetic sacroiliitis0.46 (0.21; 0.99)0.63 (0.26; 1.52)Baseline BASDAI1.02 (0.99;1.04)Baseline CRP0.99 (0.98; 1.02)Positive B270.81 (0.4;1.68)Peripheral involvement0.79 (0.4; 1.56)NSAIDs2.91 (1.47; 5.77)1.08 (0.41; 2.79)PPIs6.4 (3.25; 12.7)6.9 (2.8;17)Antibiotics1.87 (0.84; 4.16)Psychotics1.94 (0.75; 4.97)Corticosteroids1.11 (0.39; 3.11)Methotrexate2.29 (0.97; 5.38)Conclusion:Co-medication with PPIs was considered as an independent factor associated with TNF-i failure. The hypothesis that this effect is due to their interference with the gut microbiota is only speculative but, regardless of the reason for this interaction, clinicians should be aware of the potential negative effect on TNF-i response.References:[1]Bazin, T., Hooks, K.B., Barnetche, T. et al. Microbiota Composition May Predict Anti-Tnf Alpha Response in Spondyloarthritis Patients: an Exploratory Study. Sci Rep8, 5446 (2018). https://doi.org/10.1038/s41598-018-23571-4[2]Masson M, Kostine M, Barnetche T, Truchetet ME, Richez C, Schaeverbeke T. Ab0661 Co-Medications May Alter the Response to Tnf-Inhibitors in Spondyloarthritis Patients: A Pharmacomicrobiomic Effect? Annals of the Rheumatic Diseases. 1 juin 2020;79(Suppl 1):1625–6.Disclosure of Interests:None declared.
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Recchia, Stefano. "Just and Unjust Postwar Reconstruction: How Much External Interference Can Be Justified?" Ethics & International Affairs 23, no. 2 (2009): 165–87. http://dx.doi.org/10.1111/j.1747-7093.2009.00205.x.
Abstract:
This article seeks to reconcile a fundamental normative tension that underlies most international reconstruction efforts in war-torn societies: on the one hand, substantial outside interference in the domestic affairs of such societies may seem desirable to secure political stability, set up inclusive governance structures, and protect basic human rights; on the other hand, such interference is inherently paternalistic—and thus problematic—since it limits the policy options and broader freedom of maneuver of domestic political actors. I argue that for paternalistic interference in foreign countries to be justified, it needs to be strictly proportional to domestic impediments to self-government and basic rights protection. Based on this claim, I model different degrees of interference that are admissible at particular stages of the postwar reconstruction process. Extrapolating from John Rawls'sLaw of Peoples, I suggest that full-scale international trusteeship can be justified only so long as conditions on the ground remain “outlaw”—that is, so long as security remains volatile and basic rights, including the right to life, are systematically threatened. Once basic security has been reestablished, a lower degree of interference continues to be justified, until new domestic governance structures become entirely self-sustaining. During this second phase of postwar reconstruction, external actors ideally ought toshare responsibilityfor law-enforcement and administration with domestic authorities, which implies in practice that domestic and international officials should jointly approve all major decisions. I discuss various approximations of such shared responsibility in recent international peace operations and speculate about how best to ensure a timely transition toward full domestic ownership.
14
Dillon, D. G., T. Wiecki, P. Pechtel, C. Webb, F. Goer, L. Murray, M. Trivedi, et al. "A computational analysis of flanker interference in depression." Psychological Medicine 45, no. 11 (March 2, 2015): 2333–44. http://dx.doi.org/10.1017/s0033291715000276.
Abstract:
BackgroundDepression is characterized by poor executive function, but – counterintuitively – in some studies, it has been associated with highly accurate performance on certain cognitively demanding tasks. The psychological mechanisms responsible for this paradoxical finding are unclear. To address this issue, we applied a drift diffusion model (DDM) to flanker task data from depressed and healthy adults participating in the multi-site Establishing Moderators and Biosignatures of Antidepressant Response for Clinical Care for Depression (EMBARC) study.MethodOne hundred unmedicated, depressed adults and 40 healthy controls completed a flanker task. We investigated the effect of flanker interference on accuracy and response time, and used the DDM to examine group differences in three cognitive processes: prepotent response bias (tendency to respond to the distracting flankers), response inhibition (necessary to resist prepotency), and executive control (required for execution of correct response on incongruent trials).ResultsConsistent with prior reports, depressed participants responded more slowly and accurately than controls on incongruent trials. The DDM indicated that although executive control was sluggish in depressed participants, this was more than offset by decreased prepotent response bias. Among the depressed participants, anhedonia was negatively correlated with a parameter indexing the speed of executive control (r = −0.28, p = 0.007).ConclusionsExecutive control was delayed in depression but this was counterbalanced by reduced prepotent response bias, demonstrating how participants with executive function deficits can nevertheless perform accurately in a cognitive control task. Drawing on data from neural network simulations, we speculate that these results may reflect tonically reduced striatal dopamine in depression.
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Oliveira-Santos, Luiz G. R., Robert M. Dorazio, Walfrido M. Tomas, Guilherme Mourão, and Fernando A. S. Fernandez. "No evidence of interference competition among the invasive feral pig and two native peccary species in a Neotropical wetland." Journal of Tropical Ecology 27, no. 5 (August 2, 2011): 557–61. http://dx.doi.org/10.1017/s026646741100023x.
Abstract:
In South America, the invasive feral pig (Sus scrofa Linnaeus) has become established in Argentina, Uruguay, Paraguay and in a wide range within Brazil, along the southern half of the Atlantic Forest, in the cerrado (savanna) and in the Pantanal wetland. The geographical ranges of the two most common South American native peccary (Tayassu pecari Link and Pecari tajacu Linnaeus) overlap almost entirely, and the feral pig now co-occurs with them in several areas. Because feral pig, white-lipped and collared peccary are considered ecological equivalents, there has been much speculation about possible competitive interactions among them (Desbiez et al. 2009, Sicuro & Oliveira 2002).
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Hess, P. P., W. Mastropaolo, G. D. Thompson, and S. S. Levinson. "Interference of polyclonal free light chains with identification of Bence Jones proteins." Clinical Chemistry 39, no. 8 (August 1, 1993): 1734–38. http://dx.doi.org/10.1093/clinchem/39.8.1734.
Abstract:
Abstract We present a case in which kappa free light chains caused difficulty in interpreting classical urinary immunoelectrophoresis, but immunofixation electrophoresis (IFE) demonstrated the presence of a lambda-Bence Jones protein. Analysis of the urine by Ouchterlony double diffusion and IFE after gel-filtration chromatography showed that the difficulty was caused by the presence of large amounts of polyclonal free light chains. The workup also demonstrated that although IFE is the more sensitive and specific technique, IFE performed on concentrated urinary samples is especially subject to misinterpretation unless densely staining patterns are diluted and reassayed. This process of sample dilution provides a means for titrating antigen and antibody concentrations such that condition-specific patterns become visible on the gel. This workup also shows that, at some dilutions, polyclonal free light chains may migrate in the same manner as an oligoclonal band in a so-called ladder configuration. These bands were observed from both monomeric and dimeric fractions isolated by gel chromatography, consistent with reports that this pattern is largely linked to the isoelectric points of the molecules. We speculate that, in rare instances, the distinction between polyclonal and monoclonal kappa free light chains migrating as a ladder-banding pattern may be equivocal.
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Hodgetts, Ross B., Sandra L. O’Keefe, and Kyle J. Anderson. "An intact RNA interference pathway is required for expression of the mutant wing phenotype of vg21-3, a P-element-induced allele of the vestigial gene in Drosophila." Genome 55, no. 4 (April 2012): 312–26. http://dx.doi.org/10.1139/g2012-016.
Abstract:
We have determined that two P elements, P[21-3] and P[21r36], residing in the 5′-UTR of the vestigial wing gene, encode functional repressors in eye tissue. However, neither element fits a previous categorization of repressor-making elements as Type I or II. Both elements encode polypeptides that are shorter than the canonical elements they most closely resemble. DNA sequencing reveals that P[21r36] encodes an intact THAP domain that is missing in the P[21] element, which does not encode a functional repressor. Recovery of P[21-3] at sites other than vestigial (where it causes the wing mutant, vg21-3) reveals that the element can make repressor in wing tissue of sufficient activity to repress the mutant phenotype of vg21-3. Why the P[21-3] element fails to produce repressor when located at vestigial may be explained by our observation that three different mutants in the RNA interference pathway cause a partial reversion of vg21-3. We speculate that the vg and P-initiated transcripts that arise at the vg locus in the vg21-3 mutant trigger an RNA interference response that results in the mutual degradation of both transcripts.
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Paisley, A. N., K. Hayden, A. Ellis, J. Anderson, G. Wieringa, and P. J. Trainer. "Pegvisomant interference in GH assays results in underestimation of GH levels." European Journal of Endocrinology 156, no. 3 (March 2007): 315–19. http://dx.doi.org/10.1530/eje.1.02341.
Abstract:
Introduction: Pegvisomant use in acromegaly negates the use of GH levels to monitor disease activity. To achieve antagonism, plasma concentrations must be ~1000-fold greater than GH which with the high homology between the peptides makes GH measurement a challenge when pegvisomant is present. Objective: We investigated the effect of pegvisomant on GH measured using commercially available assays. Methods: Pooled serum samples with GH concentrations <0.38, 3.85 and 7.69 μg/l were spiked with increasing pegvisomant concentrations (9000–494 000μg/l). Samples were analysed by the Nichols Advantage, DPC Immulite 2000, Diasorin IRMA, Beckman Access Dxl, Tosoh AIA and Wallac Delfia assays. Results: With baseline GH <0.38 μg/l measured levels were <0.38 in all assays except Nichols, Diasorin and Beckman where GH peaked at 1.5, 9.6 and 17.7 μg/l respectively at low pegvisomant concentrations, falling thereafter. With the other two samples, measured GH levels progressively fell with increasing pegvisomant concentrations, except the Beckman assay where an increase (30.8 μg/l) was seen at a pegvisomant concentration of 9000 μg/l; and Diasorin and Tosoh where smaller increases were seen at lower pegvisomant concentrations, levels gradually falling thereafter. Conclusion: The presence of pegvisomant resulted in artefactually low measured GH in most assays. We speculate this fall is due to assay antibody-binding pegvisomant, reducing the amount of available antibody to bind actual GH thereby producing less sandwich formation: the ‘high-dose hook’ effect. In most assays, this effect is modest and results in lower GH, but the level of interference makes them unsuitable for studies on the influence of pegvisomant on GH neuroregulation.
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Soifer, Harris S. "Do Small RNAs Interfere With LINE-1?" Journal of Biomedicine and Biotechnology 2006 (2006): 1–8. http://dx.doi.org/10.1155/jbb/2006/29049.
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Long interspersed elements (LINE-1 or L1) are the most active transposable elements in the human genome. Due to their high copy number and ability to sponsor retrotransposition of nonautonomous RNA sequences, unchecked L1 activity can negatively impact the genome by a number of means. Substantial evidence in lower eukaryotes demonstrates that the RNA interference (RNAi) machinery plays a major role in containing transposon activity. Despite extensive analysis in other eukaryotes, no experimental evidence has been presented that L1-derived siRNAs exist, or that the RNAi plays a significant role in restricting L1 activity in the human genome. This review will present evidence showing a direct role for RNAi in suppressing the movement of transposable elements in other eukaryotes, as well as speculate on the role RNAi might play in protecting the human genome from LINE-1 activity.
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Ichkova, Aleksandra, Andrew M. Fukuda, Nina Nishiyama, Germaine Paris, Andre Obenaus, and Jerome Badaut. "Small Interference RNA Targeting Connexin-43 Improves Motor Function and Limits Astrogliosis After Juvenile Traumatic Brain Injury." ASN Neuro 11 (January 2019): 175909141984709. http://dx.doi.org/10.1177/1759091419847090.
Abstract:
Juvenile traumatic brain injury (jTBI) is the leading cause of death and disability for children and adolescents worldwide, but there are no pharmacological treatments available. Aquaporin 4 (AQP4), an astrocytic perivascular protein, is increased after jTBI, and inhibition of its expression with small interference RNA mitigates edema formation and reduces the number of reactive astrocytes after jTBI. Due to the physical proximity of AQP4 and gap junctions, coregulation of AQP4 and connexin 43 (Cx43) expressions, and the possibility of water diffusion via gap junctions, we decided to address the potential role of astrocytic gap junctions in jTBI pathophysiology. We evaluated the role of Cx43 in the spread of the secondary injuries via the astrocyte network, such as edema formation associated with blood–brain barrier dysfunctions, astrogliosis, and behavioral outcome. We observed that Cx43 was altered after jTBI with increased expression in the perilesional cortex and in the hippocampus at several days post injury. In a second set of experiments, cortical injection of small interference RNA against Cx43 decreased Cx43 protein expression, improved motor function recovery, and decreased astrogliosis but did not result in differences in edema formation as measured via T2-weighted imaging or diffusion-weighted imaging at 1 day or 3 days. Based on our findings, we can speculate that while decreasing Cx43 has beneficial roles, it likely does not contribute to the spread of edema early after jTBI.
21
Ravikumar, Snusha, Sindhuja Devanapally, and Antony M. Jose. "Gene silencing by double-stranded RNA from C. elegans neurons reveals functional mosaicism of RNA interference." Nucleic Acids Research 47, no. 19 (September 10, 2019): 10059–71. http://dx.doi.org/10.1093/nar/gkz748.
Abstract:
Abstract Delivery of double-stranded RNA (dsRNA) into animals can silence genes of matching sequence in diverse cell types through mechanisms that have been collectively called RNA interference. In the nematode Caenorhabditis elegans, dsRNA from multiple sources can trigger the amplification of silencing signals. Amplification occurs through the production of small RNAs by two RNA-dependent RNA polymerases (RdRPs) that are thought to be tissue-specific - EGO-1 in the germline and RRF-1 in somatic cells. Here we demonstrate that EGO-1 can compensate for the lack of RRF-1 when dsRNA from neurons is used to silence genes in intestinal cells. However, the lineal origins of cells that can use EGO-1 varies. This variability could be because random sets of cells can either receive different amounts of dsRNA from the same source or use different RdRPs to perform the same function. Variability is masked in wild-type animals, which show extensive silencing by neuronal dsRNA. As a result, cells appear similarly functional despite underlying differences that vary from animal to animal. This functional mosaicism cautions against inferring uniformity of mechanism based on uniformity of outcome. We speculate that functional mosaicism could contribute to escape from targeted therapies and could allow developmental systems to drift over evolutionary time.
22
Mohr, Harald M., and David E. J. Linden. "Separation of the Systems for Color and Spatial Manipulation in Working Memory Revealed by a Dual-task Procedure." Journal of Cognitive Neuroscience 17, no. 2 (February 2005): 355–66. http://dx.doi.org/10.1162/0898929053124929.
Abstract:
The manipulation of different kinds of content is fundamental to working memory. It has been suggested that the mere maintenance of color and spatial information occurs in parallel, but little is known about whether this holds true for manipulation as well. Using a dual-task delayed-response paradigm that required the manipulation of color and angles, this study finds that the two functions do not interfere. Conversely, interference did occur when both components of a dual-task tapped into the spatial system. Thus, color and spatial information are manipulated in parallel. A concurrent phonological task did not interfere with either maintenance or manipulation, whereas a task requiring central executive processes interfered with manipulation only. We speculate that the ventral–dorsal dissociation of visual processing is conserved for manipulation processes and that manipulation differs from maintenance in the extent to which is relies on central executive resources.
23
Bardoni, Barbara, Laetitia Davidovic, Mounia Bensaid, and Edouard W. Khandjian. "The fragile X syndrome: exploring its molecular basis and seeking a treatment." Expert Reviews in Molecular Medicine 8, no. 8 (April 21, 2006): 1–16. http://dx.doi.org/10.1017/s1462399406010751.
Abstract:
Fragile X syndrome (FXS) – the leading cause of inherited mental retardation – is an X-linked disease caused by loss of expression of the FMR1 (fragile X mental retardation 1) gene. In addition to impairment of higher-cognitive functions, FXS patients show a variety of physical and other mental abnormalities. FMRP, the protein encoded by the FMR1 gene, is thought to play a key role in translation, trafficking and targeting of mRNA in neurons. To better understand FMRP's functions, the protein partners and mRNA targets that interact with FMRP have been sought. These and functional studies have revealed links with processes such as cytoskeleton remodelling via the RhoGTPase pathway and mRNA processing via the RNA interference pathway. In this review, we focus on recent insights into the function of FMRP and speculate on how the absence of FMRP might cause the clinical phenotypes seen in FXS patients. Finally, we explore potential therapies for FXS.
24
Morris, Richard G. M. "Long-term potentiation and memory." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 358, no. 1432 (April 29, 2003): 643–47. http://dx.doi.org/10.1098/rstb.2002.1230.
Abstract:
The discovery of long-term potentiation (LTP) transformed research on the neurobiology of learning and memory. This did not happen overnight, but the discovery of an experimentally demonstrable phenomenon reflecting activity-driven neuronal and synaptic plasticity changed discussions about what might underlie learning from speculation into something much more concrete. Equally, however, the relationship between the discovery of LTP and research on the neurobiology of learning and memory has been reciprocal; for it is also true that studies of the psychological, anatomical and neurochemical basis of memory provided a developing and critical intellectual context for the physiological discovery. The emerging concept of multiple memory systems, from 1970 onwards, paved the way for the development of new behavioural and cognitive tasks, including the watermaze described in this paper. The use of this task in turn provided key evidence that pharmacological interference with an LTP induction mechanism would also interfere with learning, a finding that was by no means a foregone conclusion. This reciprocal relationship between studies of LTP and the neurobiology of memory helped the physiological phenomenon to be recognized as a major discovery.
25
BARNETT, MICHAEL N. "International paternalism and humanitarian governance." Global Constitutionalism 1, no. 3 (September 26, 2012): 485–521. http://dx.doi.org/10.1017/s2045381712000135.
Abstract:
AbstractThis article argues that paternalism is an organizing principle of the international humanitarian order. The international community is increasingly organized to preserve, protect, and promote human life, reflecting an ethics of care and impulse to intervene for the greater good. This mixture of care and control is captured by the concept of paternalism, which Gerald Dworkin famously defined as ‘the interference with a person’s liberty of action justified by reasons referring exclusively to the welfare, good, happiness, needs, interests or values of the person being coerced’. Paternalism is either present or dormant in many (if not nearly all) interventions that are designed for the betterment of people and the good of humanity. This article has four goals: 1) to reassess and examine the analytical power of this much maligned and misunderstood concept; 2) to consider the dimensions upon which paternalism varies in order to develop the concept’s value for empirical analysis; 3) to speculate how and why paternalism’s form has moved from ‘strong’ to ‘weak’ over the last hundred years; and, 4) to consider whether, why, and when paternalism might be legitimate.
26
Hernández-Ibarra, Norma Karina, Andrew R. Leitch, Pedro Cruz, and Ana M. Ibarra. "Fluorescent in situ hybridization and characterization of the SalI family of satellite repeats in the Haliotis L. species (abalone) of the Northeast Pacific." Genome 51, no. 8 (August 2008): 570–79. http://dx.doi.org/10.1139/g08-041.
Abstract:
The SalI satellite repeat previously identified in Haliotis L. (abalone) was thought to be present in H. rufescens and absent in H. fulgens . However, we show here that SalI is also found in H. fulgens and is not useful for screening hybrid individuals bred in aquaculture or occurring naturally in the wild. SalI is a family of predominantly subtelomeric tandemly repeated sequences, and sequenced clones revealed clustering to species and little intraspecific variation. Analysis of SalI sequence divergence between Haliotis species of the Northeast Pacific revealed that evolutionary distances correlate well with bathymetric and latitudinal species distributions. Analysis of the structure of the tandem repeats revealed two regions of high sequence conservation that may contain conserved transcription factor binding sites, a surprise for an apparently “non-coding” tandem repeat. We speculate that these regions might be involved in heterochromatin silencing, perhaps mediated via transcriptional activity and RNA interference. The repeats show substantial differences in their chromosomal distributions, even between individuals of the same species, indicating a dynamic organization of repeats, perhaps mediated via sequence homogenization.
27
Chen, Gavin M. "Minority Business Development: Where do we go from Here?" Review of Black Political Economy 22, no. 2 (December 1993): 5–10. http://dx.doi.org/10.1007/bf02689940.
Abstract:
It is the contention here that the development of secondary markets to add liquidity to minority and small business equity and investors will greatly increase the flow of investment funds to institutions that originate those assets. While that may be true, investment originators can also create derivatives to contain the risk or to speculate in those markets. Also, investment originators can issue bonds or certificates using their minority C&I assets as securities. It is clear that a number of avenues already exist to enhance liquidity and investment flow to investors in minority and small businesses. Why then are they not being used? The primary reason for the exclusion of such assets from the derivative and secondary markets is the risk perception. It is felt that some form of guaranty or portfolio discount would be necessary to attract investors to these markets. That would mean governmental interference and regulation. However, the government is not willing to add “full faith and credit” to another financial intermediary, especially one where the downside risk is perceptively large.
28
Baram, Yoram. "Circuit Polarity Effect of Cortical Connectivity, Activity, and Memory." Neural Computation 30, no. 11 (November 2018): 3037–71. http://dx.doi.org/10.1162/neco_a_01128.
Abstract:
Experimental constraints have traditionally implied separate studies of different cortical functions, such as memory and sensory-motor control. Yet certain cortical modalities, while repeatedly observed and reported, have not been clearly identified with one cortical function or another. Specifically, while neuronal membrane and synapse polarities with respect to a certain potential value have been attracting considerable interest in recent years, the purposes of such polarities have largely remained a subject for speculation and debate. Formally identifying these polarities as on-off neuronal polarity gates, we analytically show that cortical circuit structure, behavior, and memory are all governed by the combined potent effect of these gates, which we collectively term circuit polarity. Employing widely accepted and biologically validated firing rate and plasticity paradigms, we show that circuit polarity is mathematically embedded in the corresponding models. Moreover, we show that the firing rate dynamics implied by these models are driven by ongoing circuit polarity gating dynamics. Furthermore, circuit polarity is shown to segregate cortical circuits into internally synchronous, externally asynchronous subcircuits, defining their firing rate modes in accordance with different cortical tasks. In contrast to the Hebbian paradigm, which is shown to be susceptible to mutual neuronal interference in the face of asynchrony, circuit polarity is shown to block such interference. Noting convergence of synaptic weights, we show that circuit polarity holds the key to cortical memory, having a segregated capacity linear in the number of neurons. While memory concealment is implied by complete neuronal silencing, memory is restored by reactivating the original circuit polarity. Finally, we show that incomplete deterioration or restoration of circuit polarity results in memory modification, which may be associated with partial or false recall, or novel innovation.
29
Hung, Chien-Hui, Xugang Qiao, Pei-Tseng Lee, and Mary Gwo-Shu Lee. "Clathrin-Dependent Targeting of Receptors to the Flagellar Pocket of Procyclic-Form Trypanosoma brucei." Eukaryotic Cell 3, no. 4 (August 2004): 1004–14. http://dx.doi.org/10.1128/ec.3.4.1004-1014.2004.
Abstract:
ABSTRACT In trypanosomatids, endocytosis and exocytosis occur exclusively at the flagellar pocket, which represents about 0.43% of the pellicle membrane and is a deep invagination of the plasma membrane where the flagellum extends from the cell. Receptor molecules are selectively retained at the flagellar pocket. We studied the function of clathrin heavy chain (TbCLH) in the trafficking of the flagellar pocket receptors in Trypanosoma brucei by using the double-stranded RNA interference approach. It appears that TbCLH is essential for the survival of both the procyclic form and the bloodstream form of T. brucei, even though structures resembling large coated endocytic vesicles are absent in procyclic-form trypanosomes. Down-regulation of TbCLH by RNA interference (RNAi) for 24 h rapidly and drastically reduced the uptake of macromolecules via receptor-mediated endocytosis in procyclic-form trypanosomes. This result suggested the importance of TbCLH in receptor-mediated endocytosis of the procyclic-form trypanosome, in which the formation of large coated endocytic vesicles may not be required. Surprisingly, induction of TbCLH RNAi in the procyclic T. brucei for a period of 48 h prohibited the export of the flagellar pocket-associated transmembrane receptor CRAM from the endoplasmic reticulum to the flagellar pocket, while trafficking of the glycosylphosphatidylinositol-anchored procyclin coat was not significantly affected. After 72 h of induction of TbCLH RNAi, procyclics exhibited morphological changes to an apolar round shape without a distinct structure of the flagellar pocket and flagellum. Although trypanosomes, like other eukaryotes, use similar organelles and machinery for protein sorting and transport, our studies reveal a novel role for clathrin in the secretory pathway of trypanosomes. We speculate that the clathrin-dependent trafficking of proteins to the flagellar pocket may be essential for the biogenesis and maintenance of the flagellar pocket in trypanosomes.
30
Talkowski, M. E., M. S. Redfern, J. R. Jennings, and J. M. Furman. "Cognitive Requirements for Vestibular and Ocular Motor Processing in Healthy Adults and Patients with Unilateral Vestibular Lesions." Journal of Cognitive Neuroscience 17, no. 9 (September 2005): 1432–41. http://dx.doi.org/10.1162/0898929054985419.
Abstract:
This study investigated the role of cognition in the vestibulo-ocular reflex (VOR) and ocular pursuit using a dual-task paradigm in patients with unilateral peripheral vestibular loss and healthy adults. We hypothesized that cognitive resources are involved in successful processing and integration of vestibular and ocular motor sensory information, and this requirement would be greater in patients with vestibular dys-function. Sixteen well-compensated patients with surgically confirmed absent unilateral peripheral vestibular function and 16 healthy age-and sex-matched controls underwent seven combinations of vestibular-only, visual-only, and visual-vestibular stimuli while performing three different information processing tasks. Visual-vestibular stimuli included a semi-circular canal and an otolith stimulus provided through seated chair rotations; fixation on a laser target and sinusoidal smooth pursuit while still; and fixation on a head-fixed laser target during chair rotations. The information processing tasks were three different auditory reaction time (RT) tasks: (1) simple RT (2) disjunctive RT, and (3) choice RT. Our results showed increases in RTs in both patients and controls under all vestibular-only stimulation conditions and during ocular pursuit. Patients showed greater increases in RTs during vestibular stimulation and the more complex disjunctive and choice RT tasks. No differences between the groups were found during the visual-only or visual-vestibular interaction conditions. These results reveal interference between vestibulo-ocular processing and a concurrent RT task, suggesting that the VOR and the ocular motor system are dependent upon cognitive resources to some extent, and thus, are not fully automatic systems. We speculate that this interference with cognition occurs as a result of the sensory integration required for resolving inputs from multiple sensory streams. The particularly large decrement in information processing task performance of the patients compared with controls during vestibular stimulation suggests that compensation for unilateral vestibular loss requires continued cognitive resources.
31
Canaves, J. M., J. A. Ferragut, and J. M. Gonzalez-Ros. "Verapamil prevents the effects of daunomycin on the thermotropic phase transition of model lipid bilayers." Biochemical Journal 279, no. 2 (October 15, 1991): 413–18. http://dx.doi.org/10.1042/bj2790413.
Abstract:
High-sensitivity differential scanning calorimetry and fluorescence-depolarization techniques were used to study how the presence of daunomycin and/or verapamil affect the thermotropic behaviour of dipalmitoyl phosphatidylcholine (DPPC) vesicles. Daunomycin, a potent anti-cancer agent, perturbs the thermodynamic parameters associated with the lipid phase transition: it decreases the enthalpy change, lowers the transition temperature and reduces the co-operative behavior of the phospholipid molecules. Verapamil, on the other hand, produces smaller alterations in the lipid phase transition. However, when daunomycin and verapamil are present simultaneously in the DPPC vesicles, it is observed that verapamil prevents, in a concentration-dependent manner, the alteration in the phospholipid phase transition expected from the presence of daunomycin in the bilayer. Furthermore, drug-binding studies suggest that the observed interference of verapamil in the daunomycin/phospholipid interaction occurs without a decrease in the amount of daunomycin bound to the lipid bilayer and without the formation of a daunomycin-verapamil complex. Because of the importance of drug-membrane interactions in anthracycline cytotoxicity, we speculate that the lipid bilayer of biological membranes may provide appropriate sites at which the presence of verapamil influences the activity of daunomycin.
32
Köpke, Barbara. "Language attrition: A matter of brain plasticity?" Language, Interaction and Acquisition 12, no. 1 (July 27, 2021): 110–32. http://dx.doi.org/10.1075/lia.20015.kop.
Abstract:
Abstract While it has long been assumed that brain plasticity declines significantly with growing maturity, recent studies in adult subjects show grey and white matter changes due to language learning that suggest high adaptability of brain structures even within short time-scales. It is not known yet whether other language development phenomena, such as attrition, may also be linked to structural changes in the brain. In behavioral and neurocognitive research on language attrition and crosslinguistic influence, findings suggest high plasticity as language interaction patterns of bilingual speakers change constantly and from early stages of language acquisition onwards. In this paper we will speculate on possible links between brain plasticity and L1 attrition in adult bilinguals, with particular attention to a number of factors that are put forward in memory frameworks in order to explain forgetting: time elapsed, frequency of L1 use, and interference from L2. In order to better understand the time-scales involved in the plastic changes during bilingual development, we then discuss some recent studies of re-exposure to L1 in formerly attrited immigrants, and their implications with respect to brain plasticity.
33
Madan, Babita, Vikas Madan, Odile Weber, Philippe Tropel, Carmen Blum, Emmanuelle Kieffer, Stéphane Viville, and Hans Jörg Fehling. "The Pluripotency-Associated Gene Dppa4 Is Dispensable for Embryonic Stem Cell Identity and Germ Cell Development but Essential for Embryogenesis." Molecular and Cellular Biology 29, no. 11 (March 30, 2009): 3186–203. http://dx.doi.org/10.1128/mcb.01970-08.
Abstract:
ABSTRACT Dppa4 (developmental pluripotency-associated 4) has been identified in several high-profile screens as a gene that is expressed exclusively in pluripotent cells. It encodes a nuclear protein with an SAP-like domain and appears to be associated preferentially with transcriptionally active chromatin. Its exquisite expression pattern and results of RNA interference experiments have led to speculation that Dppa4, as well as its nearby homolog Dppa2, might play essential roles in embryonic stem (ES) cell function and/or germ cell development. To rigorously assess suggested roles, we have generated Dppa4-deficient and Dppa4/Dppa2 doubly deficient ES cells, as well as mice lacking Dppa4. Contrary to predictions, we find that Dppa4 is completely dispensable for ES cell identity and germ cell development. Instead, loss of Dppa4 in mice results in late embryonic/perinatal death and striking skeletal defects with partial penetrance. Thus, surprisingly, Dppa4-deficiency affects tissues that apparently never transcribed the gene, and at least some loss-of-function defects manifest phenotypically at an embryonic stage long after physiologic Dppa4 expression has ceased. Concomitant with targeted gene inactivation, we have introduced into the Dppa4 locus a red fluorescent marker (tandem-dimer red fluorescent protein) that is compatible with green fluorescent proteins and allows noninvasive visualization of pluripotent cells and reprogramming events.
34
Paredes, Alvaro, Sergio M. Acuña, Leopoldo Gutiérrez, and Pedro G. Toledo. "Zeta Potential of Pyrite Particles in Concentrated Solutions of Monovalent Seawater Electrolytes and Amyl Xanthate." Minerals 9, no. 10 (September 27, 2019): 584. http://dx.doi.org/10.3390/min9100584.
Abstract:
Charge screening and adsorption capacity of monovalent ions onto pyrite (Py) in aqueous suspensions and the effect of potassium amyl xanthate (PAX) has been studied by measuring the changes in zeta potential (zp) versus pH with streaming potential. PAX addition in the absence of salts leads to an increase in |zp| suggesting dissolution of the surface ferric hydroxides and recovery of bare Py, corroborating existing theories. In the presence of salt, addition of PAX at pH > 6, for which hydroxides interference in not expected, has little effect over the zp, except when Li is present. The water network around the polar head of PAX is expected to be similar to that of hydrated Li+ facilitating the linkage between them and, thus, the formation of Li-mediated Py–PAX bridges. We speculate that these bridges lead to a xanthate shield around anionic sites on Py, decreasing |zp|. An increased PAX dose amplifies the effect of Li as a Py activator but only at low salt. At high salt concentrations, >0.01 M, PAX molecules do not find room to percolate to the surface of Py. Results for monovalent cations should improve our understanding of copper flotation processes in the presence of Py in saltwater.
35
Blobel, G. A., and S. H. Orkin. "Estrogen-induced apoptosis by inhibition of the erythroid transcription factor GATA-1." Molecular and Cellular Biology 16, no. 4 (April 1996): 1687–94. http://dx.doi.org/10.1128/mcb.16.4.1687.
Abstract:
Steroid hormones regulate diverse biological functions, including programmed cell death (apoptosis). Although steroid receptors have been studied extensively, relatively little is known regarding the cellular targets through which apoptosis is triggered. We show here that the ligand-activated estrogen receptor (ER) induces apoptosis in an erythroid cell line by binding to, and consequently inhibiting the activity of, GATA-1, an erythroid transcription factor essential for the survival and maturation of erythroid precursor cells. GATA-1 inhibition is reflected in the downregulation of presumptive GATA-1 target genes. Constitutive overexpression of a GATA-binding protein resistant to the effects of the ER partially rescues ER-induced apoptosis. Induction of apoptosis by a mutant ER defective in binding to the estrogen response element but active in GATA-1 inhibition suggests that ER-mediated inhibition of GATA-1 is direct and does not require estrogen response element-dependent transcriptional activation. Thus, a lineage-restricted transcription factor, such as GATA-1, constitutes one cellular target through which steroid hormones may control apoptosis. As GATA-binding proteins are evolutionarily conserved, we speculate that members of the steroid receptor family may exert some of their diverse biological functions in different cellular contexts through interference with the function of GATA-binding proteins.
36
Vidal, Benedicto de Campos, Silvya Stuchi Maria, and Louis Bernard Klaczko. "Concanavalin A-reactive nuclear matrix glycoprotein." Brazilian Journal of Genetics 20, no. 4 (December 1997): 631–38. http://dx.doi.org/10.1590/s0100-84551997000400012.
Abstract:
The binding capacity of concanavalin A (Con A) to condensed euchromatin and heterochromatin was investigated in chicken erythrocyte nuclei (CEN), mouse liver cells, Zea mays mays meristematic cells and Drosophila melanogaster polytene chromosomes after 4 N HCl hydrolysis to determine whether binding was preferentially occurring in bands and heterochromatin. Dry mass (DM) variation was investigated in CEN by interference microscopy. Feulgen and Con A reactions were employed for all materials to correlate the loci of the two reactions. Quantifications and topological verifications were carried out by video image analysis (high performance cytometry). It was observed that 4 N HCl hydrolysis caused an important DM loss in CEN leaving a level corresponding to the average DNA DM content. In this material, Con A binding was restricted to the nuclear envelope, which reinforces the idea of the absence of a nuclear matrix in these cells. The other cell types exhibited a correspondence of Feulgen-positive and Con A-reactive areas. The Con A reaction was highly positive in the condensed chromatin areas and heterochromatin. This fact led us to speculate that Con A-positive proteins may play a role in the chromatin condensation mechanism, endowing this structure with physico-chemical stability towards acid hydrolysis and contributing to its rheological properties.
37
McKay, Derek M., Nicole L. Mancini, Jane Shearer, and Timothy Shutt. "Perturbed mitochondrial dynamics, an emerging aspect of epithelial-microbe interactions." American Journal of Physiology-Gastrointestinal and Liver Physiology 318, no. 4 (April 1, 2020): G748—G762. http://dx.doi.org/10.1152/ajpgi.00031.2020.
Abstract:
Mitochondria exist in a complex network that is constantly remodeling via the processes of fission and fusion in response to intracellular conditions and extracellular stimuli. Excessive fragmentation of the mitochondrial network because of an imbalance between fission and fusion reduces the cells’ capacity to generate ATP and can be a forerunner to cell death. Given the critical roles mitochondria play in cellular homeostasis and innate immunity, it is not surprising that many microbial pathogens can disrupt mitochondrial activity. Here we note the putative contribution of mitochondrial dysfunction to gut disease and review data showing that infection with microbial pathogens can alter the balance between mitochondrial fragmentation and fusion, preventing normal remodeling (i.e., dynamics) and can lead to cell death. Current data indicate that infection of epithelia or macrophages with microbial pathogens will ultimately result in excessive fragmentation of the mitochondrial network. Concerted research efforts are required to elucidate fully the processes that regulate mitochondrial dynamics, the mechanisms by which microbes affect epithelial mitochondrial fission and/or fusion, and the implications of this for susceptibility to infectious disease. We speculate that the commensal microbiome of the gut may be important for normal epithelial mitochondrial form and function. Drugs designed to counteract the effect of microbial pathogen interference with mitochondrial dynamics may be a new approach to infectious disease at mucosal surfaces.
38
Iffat Rahmatullah, Shadma. "Significance of Mother Tongue influence on Saudi Female EFL Learners: a Critical Discourse Analysis." Arab World English Journal, no. 2 (January 15, 2021): 329–42. http://dx.doi.org/10.24093/awej/mec2.24.
Abstract:
The speculation, that the Saudi EFL learners with less exposure to the target language exhibit more mother tongue influence on their second language speaking, is apparent. The phonetic similarity of two languages helps EFL learners to grasp the lexical accent with the accurate articulation of the words from the second language. However, the difference in sound patterns in various languages prompts the learners to mispronounce the words more frequently. This critical study endeavors to evaluate the influential aspects of the mother tongue on the EFL learners’ second language (L2) discourse. This research is carried out through a qualitative method for critical discourse analysis to answer the main question; what significant errors students make that reflect their mother tongue influence? For a comparative study, the participants are the Saudi undergraduates from multidimensional sections of female colleges in King Khalid University and the non-native English-speaking teachers from five different nations, who also manifest the influence of their mother tongue on English language speaking. Their recorded presentations and conversations were analyzed to identify the interference of their mother tongue on their English language performance. The language patterns of both students and the teachers eventually affect their English language efficiency. The significant outcome of this study reveals the possibility of the pros and cons of the mother tongue on L2 learning. The data also revealed that the inability of faculty members to produce the flawless accent of the English language has a significant effect on Saudi learners’ oral performance.
39
Liebau, Max C., D. Lang, J. Böhm, N. Endlich, Martin J. Bek, Ian Witherden, Peter W. Mathieson, Moin A. Saleem, Hermann Pavenstädt, and Karl-Georg Fischer. "Functional expression of the renin-angiotensin system in human podocytes." American Journal of Physiology-Renal Physiology 290, no. 3 (March 2006): F710—F719. http://dx.doi.org/10.1152/ajprenal.00475.2004.
Abstract:
Experimental and clinical studies impressively demonstrate that angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) significantly reduce proteinuria and retard progression of glomerular disease. The underlying intraglomerular mechanisms are not yet fully elucidated. As podocyte injury constitutes a critical step in the pathogenesis of glomerular proteinuria, beneficial effects of ACEI and ARB may partially result from interference with a local renin-angiotensin system (RAS) in podocytes. The knowledge of expression and function of a local RAS in podocytes is limited. In this study, we demonstrate functional expression of key components of the RAS in differentiated human podocytes: podocytes express mRNA for angiotensinogen, renin, ACE type 1, and the AT1 and AT2 angiotensin receptor subtypes. In Western blot experiments and immunostainings, expression of the AT1 and AT2 receptor was demonstrated both in differentiated human podocytes and in human kidney cortex. ANG II induced a concentration-dependent increase in cytosolic Ca2+ concentration via AT1 receptors in differentiated human podocytes, whereas it did not increase cAMP. Furthermore, ANG II secretion was detected, which was blocked by neither the ACEI captopril nor the renin inhibitor remikiren nor the chymase inhibitor chymostatin. ANG II secretion of podocytes was not increased by mechanical stress. Finally, ANG II was found to increase staurosporine-induced apoptosis in podocytes. We speculate that ACEI and ARB exert their beneficial effects, in part, by interfering with a local RAS in podocytes. Further experiments are required to identify the underlying molecular mechanism(s) of podocyte protection.
40
Zeiner, Gusti M., Robert A. Hitchcock, Nancy R. Sturm, and David A. Campbell. "3′-End Polishing of the Kinetoplastid Spliced Leader RNA Is Performed by SNIP, a 3′→5′ Exonuclease with a Motley Assortment of Small RNA Substrates." Molecular and Cellular Biology 24, no. 23 (December 1, 2004): 10390–96. http://dx.doi.org/10.1128/mcb.24.23.10390-10396.2004.
Abstract:
ABSTRACT In all trypanosomatids, trans splicing of the spliced leader (SL) RNA is a required step in the maturation of all nucleus-derived mRNAs. The SL RNA is transcribed with an oligo-U 3′ extension that is removed prior to trans splicing. Here we report the identification and characterization of a nonexosomal, 3′→5′ exonuclease required for SL RNA 3′-end formation in Trypanosoma brucei. We named this enzyme SNIP (for snRNA incomplete 3′ processing). The central 158-amino-acid domain of SNIP is related to the exonuclease III (ExoIII) domain of the 3′→5′ proofreading ε subunit of Escherichia coli DNA polymerase III holoenzyme. SNIP had a preference for oligo(U) 3′ extensions in vitro. RNA interference-mediated knockdown of SNIP resulted in a growth defect and correlated with the accumulation of one- to two- nucleotide 3′ extensions of SL RNA, U2 and U4 snRNAs, a five-nucleotide extension of 5S rRNA, and the destabilization of U3 snoRNA and U2 snRNA. SNIP-green fluorescent protein localized to the nucleoplasm, and substrate SL RNA derived from SNIP knockdown cells showed wild-type cap 4 modification, indicating that SNIP acts on SL RNA after cytosolic trafficking. Since the primary SL RNA transcript was not the accumulating species in SNIP knockdown cells, SL RNA 3′-end formation is a multistep process in which SNIP provides the ultimate 3′-end polishing. We speculate that SNIP is part of an organized nucleoplasmic machinery responsible for processing of SL RNA.
41
Raafat, Dina, Kristine von Bargen, Albert Haas, and Hans-Georg Sahl. "Insights into the Mode of Action of Chitosan as an Antibacterial Compound." Applied and Environmental Microbiology 74, no. 12 (May 2, 2008): 3764–73. http://dx.doi.org/10.1128/aem.00453-08.
Abstract:
ABSTRACT Chitosan is a polysaccharide biopolymer that combines a unique set of versatile physicochemical and biological characteristics which allow for a wide range of applications. Although its antimicrobial activity is well documented, its mode of action has hitherto remained only vaguely defined. In this work we investigated the antimicrobial mode of action of chitosan using a combination of approaches, including in vitro assays, killing kinetics, cellular leakage measurements, membrane potential estimations, and electron microscopy, in addition to transcriptional response analysis. Chitosan, whose antimicrobial activity was influenced by several factors, exhibited a dose-dependent growth-inhibitory effect. A simultaneous permeabilization of the cell membrane to small cellular components, coupled to a significant membrane depolarization, was detected. A concomitant interference with cell wall biosynthesis was not observed. Chitosan treatment of Staphylococcus simulans 22 cells did not give rise to cell wall lysis; the cell membrane also remained intact. Analysis of transcriptional response data revealed that chitosan treatment leads to multiple changes in the expression profiles of Staphylococcus aureus SG511 genes involved in the regulation of stress and autolysis, as well as genes associated with energy metabolism. Finally, a possible mechanism for chitosan's activity is postulated. Although we contend that there might not be a single classical target that would explain chitosan's antimicrobial action, we speculate that binding of chitosan to teichoic acids, coupled with a potential extraction of membrane lipids (predominantly lipoteichoic acid) results in a sequence of events, ultimately leading to bacterial death.
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Shine, R., and M. Firmage. "Battles for mates and food: Intraspecific combat in island tigersnakes (Notechis ater) from southern Australia." Amphibia-Reptilia 17, no. 1 (1996): 55–65. http://dx.doi.org/10.1163/156853896x00298.
Abstract:
AbstractMale-male combat occurs in mainland populations of tigersnakes (Notechis scutatus), but authorities have disagreed as to whether or not this behaviour also occurs in island tigersnakes (Notechis ater). In this paper, we confirm that intraspecific combat frequently occurs between island tigersnakes maintained in captivity. Two different kinds of combat bouts were observed. We interpret the first type (ritualised "wrestling" matches between large adult males) as a reflection of sexual competition. This behaviour was seen in snakes from each of the island populations investigated, including Tasmania. Agonistic behaviour was exhibited by females and juveniles as well as by adult males: however, this second type of combat was always initiated by the introduction of food items to the enclosure, and incorporated vigorous biting as well as (or instead of) wrestling. Further observations, in the field as well as in captivity, are needed before we can interpret the functional significance of this behaviour. The food-induced combat may be an artifact of high densities of captive snakes, or alternatively may be exhibited in the wild also. We speculate that the high abundance of tigersnakes on some islands, and the highly clumped nature of prey resources (e.g. muttonbird chicks) in both space and time, may have favoured direct interference competition for prey items between island tigersnakes. If so, some elements of the social system of island tigersnakes may resemble the condition seen in many lizard species, rather than in other snakes.
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Egner, Tobias. "Right Ventrolateral Prefrontal Cortex Mediates Individual Differences in Conflict-driven Cognitive Control." Journal of Cognitive Neuroscience 23, no. 12 (December 2011): 3903–13. http://dx.doi.org/10.1162/jocn_a_00064.
Abstract:
Conflict adaptation—a conflict-triggered improvement in the resolution of conflicting stimulus or response representations—has become a widely used probe of cognitive control processes in both healthy and clinical populations. Previous fMRI studies have localized activation foci associated with conflict resolution to dorsolateral PFC (dlPFC). The traditional group analysis approach employed in these studies highlights regions that are, on average, activated during conflict resolution, but does not necessarily reveal areas mediating individual differences in conflict resolution, because between-subject variance is treated as noise. Here, we employed a complementary approach to elucidate the neural bases of variability in the proficiency of conflict-driven cognitive control. We analyzed two independent fMRI data sets of face–word Stroop tasks by using individual variability in the behavioral expression of conflict adaptation as the metric against which brain activation was regressed while controlling for individual differences in mean RT and Stroop interference. Across the two experiments, a replicable neural substrate of individual variation in conflict adaptation was found in ventrolateral PFC (vlPFC), specifically, in the right inferior frontal gyrus, pars orbitalis (BA 47). Unbiased regression estimates showed that variability in activity in this region accounted for ∼40% of the variance in behavioral expression of conflict adaptation across subjects, thus documenting a heretofore unsuspected key role for vlPFC in mediating conflict-driven adjustments in cognitive control. We speculate that vlPFC plays a primary role in conflict control that is supplemented by dlPFC recruitment under conditions of suboptimal performance.
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Martel, Fátima, Rosário Monteiro, and Conceição Calhau. "Effect of polyphenols on the intestinal and placental transport of some bioactive compounds." Nutrition Research Reviews 23, no. 1 (April 15, 2010): 47–64. http://dx.doi.org/10.1017/s0954422410000053.
Abstract:
Polyphenols are a group of widely distributed phytochemicals present in most foods of vegetable origin. A growing number of biological effects have been attributed to these molecules in the past few years and only recently has their interference with the transport capacity of epithelial barriers received attention. This review will present data obtained concerning the effect of polyphenols upon the transport of some compounds (organic cations, glucose and the vitamins thiamin and folic acid) at the intestinal and placental barriers. Important conclusions can be drawn: (i) different classes of polyphenols affect transport of these bioactive compounds at the intestinal epithelia and the placenta; (ii) different compounds belonging to the same phenolic family often possess opposite effects upon transport of a given molecule; (iii) the acute and chronic/short-term and long-term exposures to polyphenols do not produce parallel results and, therefore, care should be taken when extrapolating results; (iv) the effect of polyphenolics in combination may be very different from the expected ones taking into account the effect of each of these compounds alone, and so care should be taken when speculating on the effect of a drink based on the effect of one component only; (v) care should be taken in drawing conclusions for alcoholic beverages from results obtained with ethanol alone. Although most of the data reviewed in the present paper refer to in vitro experiments with cell-culture systems, these studies raise a concern about possible changes in the bioavailability of substrates upon concomitant ingestion of polyphenols.
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Barnett, Michael. "PATERNALISM AND GLOBAL GOVERNANCE." Social Philosophy and Policy 32, no. 1 (2015): 216–43. http://dx.doi.org/10.1017/s026505251500014x.
Abstract:
Abstract:Contemporary global governance is organized around an odd pairing: care and control. On the one hand, much of global governance is designed to reduce human suffering and improve human flourishing, with the important caveat that individuals should be allowed to decide for themselves how they want to live their lives. On the other hand, these global practices of care are also entangled with acts of control. Peacebuilding, public health, emergency aid, human rights, and development are expressions of this tension between care and control. There is a concept that captures this tension: paternalism. Drawing on our moral intuitions, I argue that paternalism is the attempt by one actor to substitute his judgment for another actor's on the grounds that such an imposition will improve the welfare of the target actor. After discussing and defending this definition, I note how our unease with paternalism seems to grow as we scale up from the interpersonal to the international, which I argue owes to the evaporation of community and equality. After exploring the implications of this definition and distinguishing it from other forms of intervention, I consider how different elements of paternalism combine to generate different configurations. Specifically, I point to five dimensions that are most relevant for examining the paternalism found in contemporary global and humanitarian governance: the tools used to restrict another actor’s liberty (force versus information); the scope of the interference (wide versus narrow); the purpose of the intervention (prevention of harm versus emancipation); the source of the paternalizer’s confidence (faith versus evidence); and the mechanisms of accountability (internal versus external). These different elements often correlate historically, suggestive of two ideal types of global paternalism: strong and weak. Contemporary global and humanitarian governance is largely the weak variety: force is severely proscribed, interference is relatively restricted, the paternalizer’s confidence has epistemic roots, and accountability to local populations remains a noble but rarely practiced goal. I further speculate that a major reason for this difference is the effects of liberalism and rationalization. I use this taxonomy to suggest how two different global efforts to improve the lives of those peoples living in what were perceived to be unstable and illiberal territories — the civilizing missions of the nineteenth century and the peacebuilding operations of the post-Cold War period — exhibited different kinds of paternalism. I conclude by reflecting on the ethics of international paternalism.
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Kotorashvili, Adam, Scott J. Russo, Surafel Mulugeta, Susan Guttentag, and Michael F. Beers. "Anterograde Transport of Surfactant Protein C Proprotein to Distal Processing Compartments Requires PPDY-mediated Association with Nedd4 Ubiquitin Ligases." Journal of Biological Chemistry 284, no. 24 (April 14, 2009): 16667–78. http://dx.doi.org/10.1074/jbc.m109.002816.
Abstract:
Biosynthesis of surfactant protein C (SP-C) by alveolar type 2 cells requires proteolytic processing of a 21-kDa propeptide (proSP-C21) in post-Golgi compartments to yield a 3.7-kDa mature form. Scanning alanine mutagenesis, binding assays, and co-immunoprecipitation were used to characterize the proSP-C targeting domain. Delivery of proSP-C21 to distal processing organelles is dependent upon the NH2-terminal cytoplasmic SP-C propeptide, which contains a conserved PPDY motif. In A549 cells, transfection of EGFP/proSP-C21 constructs containing polyalanine substitution for Glu11–Thr18, 13PPDY16, or 14P,16Y produced endoplasmic reticulum retention of the fusion proteins. Protein-protein interactions of proSP-C with known WW domains were screened using a solid-phase array that revealed binding of the proSP-C NH2 terminus to several WW domains found in the Nedd4 family of E3 ligases. Specificity of the interaction was confirmed by co-immunoprecipitation of proSP-C and Nedd4 or Nedd4-2 in epithelial cell lines. By Western blotting and reverse transcription-PCR, both forms were detected in primary human type 2 cells. Knockdown of Nedd4-2 by small interference RNA transfection of cultured human type 2 cells blocked processing of 35S-labeled proSP-C21. Mutagenesis of potential acceptor sites for ubiquitination in the cytosolic domain of proSP-C (Lys6, Lys34, or both) failed to inhibit trafficking of EGFP/proSP-C21. These results indicate that PPDY-mediated interaction with Nedd4 E3-ligases is required for trafficking of proSP-C. We speculate that the Nedd4/proSP-C tandem is part of a larger protein complex containing a ubiquitinated component that further directs its transport.
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Blobel, G. A., C. A. Sieff, and S. H. Orkin. "Ligand-dependent repression of the erythroid transcription factor GATA-1 by the estrogen receptor." Molecular and Cellular Biology 15, no. 6 (June 1995): 3147–53. http://dx.doi.org/10.1128/mcb.15.6.3147.
Abstract:
High-dose estrogen administration induces anemia in mammals. In chickens, estrogens stimulate outgrowth of bone marrow-derived erythroid progenitor cells and delay their maturation. This delay is associated with down-regulation of many erythroid cell-specific genes, including alpha- and beta-globin, band 3, band 4.1, and the erythroid cell-specific histone H5. We show here that estrogens also reduce the number of erythroid progenitor cells in primary human bone marrow cultures. To address potential mechanisms by which estrogens suppress erythropoiesis, we have examined their effects on GATA-1, an erythroid transcription factor that participates in the regulation of the majority of erythroid cell-specific genes and is necessary for full maturation of erythrocytes. We demonstrate that the transcriptional activity of GATA-1 is strongly repressed by the estrogen receptor (ER) in a ligand-dependent manner and that this repression is reversible in the presence of 4-hydroxytamoxifen. ER-mediated repression of GATA-1 activity occurs on an artificial promoter containing a single GATA-binding site, as well as in the context of an intact promoter which is normally regulated by GATA-1. GATA-1 and ER bind to each other in vitro in the absence of DNA. In coimmunoprecipitation experiments using transfected COS cells, GATA-1 and ER associate in a ligand-dependent manner. Mapping experiments indicate that GATA-1 and the ER form at least two contacts, which involve the finger region and the N-terminal activation domain of GATA-1. We speculate that estrogens exert effects on erythropoiesis by modulating GATA-1 activity through protein-protein interaction with the ER. Interference with GATA-binding proteins may be one mechanism by which steroid hormones modulate cellular differentiation.
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Arega, Sintayehu, Anne Conan, Claude T. Sabeta, Jan E. Crafford, Jeanette Wentzel, Bjorn Reininghaus, Louise Biggs, et al. "Rabies Vaccination of 6-Week-Old Puppies Born to Immunized Mothers: A Randomized Controlled Trial in a High-Mortality Population of Owned, Free-Roaming Dogs." Tropical Medicine and Infectious Disease 5, no. 1 (March 12, 2020): 45. http://dx.doi.org/10.3390/tropicalmed5010045.
Abstract:
To achieve global elimination of human rabies from dogs by 2030, evidence-based strategies for effective dog vaccination are needed. Current guidelines recommend inclusion of dogs younger than 3 months in mass rabies vaccination campaigns, although available vaccines are only recommended for use by manufacturers in older dogs, ostensibly due to concerns over interference of maternally-acquired immunity with immune response to the vaccine. Adverse effects of vaccination in this age group of dogs have also not been adequately assessed under field conditions. In a single-site, owner-blinded, randomized, placebo-controlled trial in puppies born to mothers vaccinated within the previous 18 months in a high-mortality population of owned, free-roaming dogs in South Africa, we assessed immunogenicity and effect on survival to all causes of mortality of a single dose of rabies vaccine administered at 6 weeks of age. We found that puppies did not have appreciable levels of maternally-derived antibodies at 6 weeks of age (geometric mean titer 0.065 IU/mL, 95% CI 0.061–0.069; n = 346), and that 88% (95% CI 80.7–93.3) of puppies vaccinated at 6 weeks had titers ≥0.5 IU/mL 21 days later (n = 117). Although the average effect of vaccination on survival was not statistically significant (hazard ratio [HR] 1.35, 95% CI 0.83–2.18), this effect was modified by sex (p = 0.02), with the HR in females 3.09 (95% CI 1.24–7.69) and the HR in males 0.79 (95% CI 0.41–1.53). We speculate that this effect is related to the observed survival advantage that females had over males in the unvaccinated group (HR 0.27; 95% CI 0.11–0.70), with vaccination eroding this advantage through as-yet-unknown mechanisms.
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Jin, Chichuan, Chris Done, and Martin Ward. "Reobserving the NLS1 galaxy RE J1034+396 – I. The long-term, recurrent X-ray QPO with a high significance." Monthly Notices of the Royal Astronomical Society 495, no. 4 (June 10, 2020): 3538–50. http://dx.doi.org/10.1093/mnras/staa1356.
Abstract:
ABSTRACT RE J1034+396 is a narrow-line Seyfert 1 galaxy (NLS1) in which the first significant X-ray quasi-periodic oscillation (QPO) in an active galactic nucleus (AGN) was observed in 2007. We report the detection of this QPO in a recent XMM–Newton observation in 2018 with an even higher significance. The quality factor of this QPO is 20, and its period is 3550 ± 80 s, which is 250 ± 100 s shorter than in 2007. While the QPO’s period has no significant energy dependence, its fractional root mean square variability increases from 4 per cent in 0.3–1 keV to 12 per cent in 1–4 keV bands. An interesting phenomenon is that the QPO in 0.3–1 keV leads that in the 1–4 keV bands by 430 ± 50 s with a high coherence, opposite to the soft X-ray lag reported for the observation in 2007. We speculate that the QPO has an intrinsic hard lag, while the previous reported soft lag is caused by the interference of stochastic variability. This soft X-ray lead in the new data supports the idea that the QPO of RE J1034+396 is a possible AGN counterpart of the 67 Hz high-frequency QPO seen in the black hole binary GRS 1915+105. We also search for QPO harmonics, but do not find any significant signals. Our new data reinforce previous results that the QPO is seen in a specific spectral state, as the only two observations showing no significant QPO signal exhibit an even stronger soft X-ray excess than the other six observations that display the QPO. Therefore, our results imply that the QPO in RE J1034+396 is physically linked to a soft X-ray component.
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Slonim, T., A. Jacobson, L. Haase-Alasantro, M. Marvin, C. Frank, and C. Murphy. "A-19 Inhibition in Metabolic Syndrome and its Relationship to Orbitofrontal Cortex Activation During Sucrose Evaluation." Archives of Clinical Neuropsychology 34, no. 6 (July 25, 2019): 878. http://dx.doi.org/10.1093/arclin/acz034.19.
Abstract:
Abstract Objective Metabolic syndrome(MetS) is associated with disinhibited eating,executive dysfunction,and increased risk of dementia. The orbitofrontal cortex(OFC) has been implicated in literature as an area involved with decision making and reward. Decreased OFC volume has been linked to disinhibited eating and poorer executive functioning skills.However,research examining executive functioning in individuals with MetS fails to address the role of inhibition as it pertains to consumption and risk of developing MetS. We examined the relationship between neuropsychological performance and OFC activation after receiving and rating a sucrose stimulus to determine if OFC activation is associated with executive functioning deficits that may lead to developing MetS. Method Participants were categorized by MetS status(n = 46) and Control(n = 34) with mean age of 49.13±20.29years. During an fMRI session, the Blood-Oxygenation-Level-Dependent(BOLD) response of OFC was recorded while participants rated the pleasantness of an aqueous sucrose solution. Participants were administered the Color-Word Interference Test outside the scanner. Partial Correlation analyses controlling for age examined the relationship between OFC activation during hedonic ratings of sucrose and cognitive performance. Results There was a significant negative relationship between left OFC activity and Color-Word Interference:Inhibition performance for Controls(r(42) = -.365, p = .015) as compared to MetS(r(30) = .141,p > .05). Conclusions Less activity in the OFC during sucrose hedonic rating was associated with better performance on the Inhibition condition for Controls. We speculate that decreased activation in the OFC after sucrose consumption reflects intact executive functioning and perhaps even a preventative factor to developing MetS. Alternatively, it could indicate that Controls are actively inhibiting hedonic responses to sucrose which improves their ability on a test of inhibition.