127 research outputs found

    Respirable antisense oligonucleotides: a new drug class for respiratory disease

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    Respirable antisense oligonucleotides (RASONs), which attenuate specific disease-associated mRNAs, represent a new class of respiratory therapeutics with considerable potential. RASONs overcome previous obstacles that have impeded the development of antisense therapeutics targeting diseases in other organ systems. RASONs are delivered directly to the target tissue via inhalation; their uptake seems to be enhanced by cationic properties inherent in pulmonary surfactant, and, because of the markedly different target properties of mRNA and proteins, they can have very long durations of effect compared with traditional drugs targeting the protein of the same gene. RASONs contain chemical modifications that decrease their degradation by cellular nucleases. However, total insensitivity to nucleases is probably not an optimal design criterion for RASONs, because moderate nuclease sensitivity can prevent their systemic delivery, decreasing the potential for systemic toxicity. EPI-2010 is a 21-mer phosphorothioate RASON that attenuates bronchoconstriction, inflammation and surfactant depletion in preclinical models of human asthma, has a duration of effect of seven days, and seems to undergo minimal systemic delivery

    Completeness and timeliness of tuberculosis notification in Taiwan

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    Tuberculosis (TB) is a notifiable disease by the Communicable Disease Control Law in Taiwan. Several measures have been undertaken to improve reporting of TB but the completeness and timeliness of TB notification in Taiwan has not yet been systemically evaluated

    The 2dF Galaxy Redshift Survey: correlation functions, peculiar velocities and the matter density of the Universe

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    We present a detailed analysis of the two-point correlation function, ΞΎ(Οƒ, Ο€), from the 2dF Galaxy Redshift Survey (2dFGRS). The large size of the catalogue, which contains ∼220 000 redshifts, allows us to make high-precision measurements of various properties of the galaxy clustering pattern. The effective redshift at which our estimates are made is zsβ‰ˆ 0.15, and similarly the effective luminosity, Lsβ‰ˆ 1.4L*. We estimate the redshift-space correlation function, ΞΎ(s), from which we measure the redshift-space clustering length, s0= 6.82 Β± 0.28 hβˆ’1 Mpc. We also estimate the projected correlation function, Ξ(Οƒ), and the real-space correlation function, ΞΎ(r), which can be fit by a power law (r/r0), with r0= 5.05 Β± 0.26 hβˆ’1 Mpc, Ξ³r= 1.67 Β± 0.03. For r≳ 20 hβˆ’1 Mpc, ΞΎ drops below a power law as, for instance, is expected in the popular Ξ› cold dark matter model. The ratio of amplitudes of the real- and redshift-space correlation functions on scales of 8–30 hβˆ’1 Mpc gives an estimate of the redshift-space distortion parameter Ξ². The quadrupole moment of ΞΎ(Οƒ, Ο€) on scales 30–40 hβˆ’1 Mpc provides another estimate of Ξ². We also estimate the distribution function of pairwise peculiar velocities, Ζ’(v), including rigorously the significant effect due to the infall velocities, and we find that the distribution is well fit by an exponential form. The accuracy of our ΞΎ(Οƒ, Ο€) measurement is sufficient to constrain a model, which simultaneously fits the shape and amplitude of ΞΎ(r) and the two redshift-space distortion effects parametrized by Ξ² and velocity dispersion, a. We find Ξ²= 0.49 Β± 0.09 and a= 506 Β± 52 km sβˆ’1, although the best-fitting values are strongly correlated. We measure the variation of the peculiar velocity dispersion with projected separation, a(Οƒ), and find that the shape is consistent with models and simulations. This is the first time that Ξ² and Ζ’(v) have been estimated from a self-consistent model of galaxy velocities. Using the constraints on bias from recent estimates, and taking account of redshift evolution, we conclude that Ξ² (L=L*, z= 0) = 0.47 Β± 0.08, and that the present-day matter density of the Universe, Ξ©mβ‰ˆ 0.3, consistent with other 2dFGRS estimates and independent analyses

    State-dependent distributed-delay model of orthogonal cutting

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    In this paper we present a model of turning operations with state-dependent distributed time delay. We apply the theory of regenerative machine tool chat- ter and describe the dynamics of the tool-workpiece sys- tem during cutting by delay-diferential equations. We model the cutting-force as the resultant of a force sys- tem distributed along the rake face of the tool, which results in a short distributed delay in the governing equation superimposed on the large regenerative de- lay. According to the literature on stress distribution along the rake face, the length of the chip-tool inter- face, where the distributed cutting-force system is act- ing, is function of the chip thickness, which depends on the vibrations of the tool-workpiece system due to the regenerative efect. Therefore, the additional short de- lay is state-dependent. It is shown that involving state- dependent delay in the model does not afect linear sta- bility properties, but does afect the nonlinear dynamics of the cutting process. Namely, the sense of the Hopf bi- furcation along the stability boundaries may turn from sub- to supercritical at certain spindle speed regions

    Narrative and Cognitive Modeling: Insights From Beckett Exploring Mind's Complexity

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    Complex systems exacerbate a common problem for scientific enquiry: the difficulty of creating models able to discriminate fundamental elements or patterns from random behaviours or corollary components in the event or process at issue. This chapter argues that a similar tension between order and randomness has been a chief modelling problem of Samuel Beckett’s narratives, tied to his interest in a specific kind of complex system (the mind) and its emergent properties (consciousness and the narrative sense of self). Bulding on narratology, complex system frameworks, cognitive theories of emergence and of scientific modelling, this chapter introduces the idea of β€œfictional cognitive modelling”. Through this concept, the chapter analyses Beckett’s treatment of narrative devices as formal tools for the creation of β€œexploratory models” able to atomise the emerging unity of conscious experience and of a narrative sense of self into its core components (defined as the β€œnarrative dynamic core”). It concludes by suggesting that Beckett’s narrative method shows how literature can occupy a proper position in the investigation and exploration of complex systems

    Incontinence in Individuals with Rett Syndrome: A Comparative Study

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    Frequency and type of incontinence and its association with other variables were assessed in females with Rett Syndrome (RS) (n = 63), using an adapted Dutch version of the β€˜Parental Questionnaire: Enuresis/Urinary Incontinence’ (Beetz et al. 1994). Also, incontinence in RS was compared to a control group consisting of females with non-specific (mixed) intellectual disability (n = 26). Urinary incontinence (UI) (i.e., daytime incontinence and nocturnal enuresis) and faecal incontinence (FI) were found to be common problems among females with RS that occur in a high frequency of days/nights. UI and FI were mostly primary in nature and occur independent of participants’ age and level of adaptive functioning. Solid stool, lower urinary tract symptoms and urinary tract infections (UTI’s) were also common problems in females with RS. No differences in incontinence between RS and the control group were found, except for solid stool that was more common in RS than in the control group. It is concluded that incontinence is not part of the behavioural phenotype of RS, but that there is an increased risk for solid stool in females with RS

    Feed-Forward Segmentation of Figure-Ground and Assignment of Border-Ownership

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    Figure-ground is the segmentation of visual information into objects and their surrounding backgrounds. Two main processes herein are boundary assignment and surface segregation, which rely on the integration of global scene information. Recurrent processing either by intrinsic horizontal connections that connect surrounding neurons or by feedback projections from higher visual areas provide such information, and are considered to be the neural substrate for figure-ground segmentation. On the contrary, a role of feedforward projections in figure-ground segmentation is unknown. To have a better understanding of a role of feedforward connections in figure-ground organization, we constructed a feedforward spiking model using a biologically plausible neuron model. By means of surround inhibition our simple 3-layered model performs figure-ground segmentation and one-sided border-ownership coding. We propose that the visual system uses feed forward suppression for figure-ground segmentation and border-ownership assignment

    Investigation of the Genes Involved in Antigenic Switching at the vlsE Locus in Borrelia burgdorferi: An Essential Role for the RuvAB Branch Migrase

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    Persistent infection by pathogenic organisms requires effective strategies for the defense of these organisms against the host immune response. A common strategy employed by many pathogens to escape immune recognition and clearance is to continually vary surface epitopes through recombinational shuffling of genetic information. Borrelia burgdorferi, a causative agent of Lyme borreliosis, encodes a surface-bound lipoprotein, VlsE. This protein is encoded by the vlsE locus carried at the right end of the linear plasmid lp28-1. Adjacent to the expression locus are 15 silent cassettes carrying information that is moved into the vlsE locus through segmental gene conversion events. The protein players and molecular mechanism of recombinational switching at vlsE have not been characterized. In this study, we analyzed the effect of the independent disruption of 17 genes that encode factors involved in DNA recombination, repair or replication on recombinational switching at the vlsE locus during murine infection. In Neisseria gonorrhoeae, 10 such genes have been implicated in recombinational switching at the pilE locus. Eight of these genes, including recA, are either absent from B. burgdorferi, or do not show an obvious requirement for switching at vlsE. The only genes that are required in both organisms are ruvA and ruvB, which encode subunits of a Holliday junction branch migrase. Disruption of these genes results in a dramatic decrease in vlsE recombination with a phenotype similar to that observed for lp28-1 or vls-minus spirochetes: productive infection at week 1 with clearance by day 21. In SCID mice, the persistence defect observed with ruvA and ruvB mutants was fully rescued as previously observed for vlsE-deficient B. burgdorferi. We report the requirement of the RuvAB branch migrase in recombinational switching at vlsE, the first essential factor to be identified in this process. These findings are supported by the independent work of Lin et al. in the accompanying article, who also found a requirement for the RuvAB branch migrase. Our results also indicate that the mechanism of switching at vlsE in B. burgdorferi is distinct from switching at pilE in N. gonorrhoeae, which is the only other organism analyzed genetically in detail. Finally, our findings suggest a unique mechanism for switching at vlsE and a role for currently unidentified B. burgdorferi proteins in this process

    Severity dependent distribution of impairments in PSP and CBS: Interactive visualizations

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    BACKGROUND: Progressive supranuclear palsy (PSP) -Richardson's Syndrome and Corticobasal Syndrome (CBS) are the two classic clinical syndromes associated with underlying four repeat (4R) tau pathology. The PSP Rating Scale is a commonly used assessment in PSP clinical trials; there is an increasing interest in designing combined 4R tauopathy clinical trials involving both CBS and PSP. OBJECTIVES: To determine contributions of each domain of the PSP Rating Scale to overall severity and characterize the probable sequence of clinical progression of PSP as compared to CBS. METHODS: Multicenter clinical trial and natural history study data were analyzed from 545 patients with PSP and 49 with CBS. Proportional odds models were applied to model normalized cross-sectional PSP Rating Scale, estimating the probability that a patient would experience impairment in each domain using the PSP Rating Scale total score as the index of overall disease severity. RESULTS: The earliest symptom domain to demonstrate impairment in PSP patients was most likely to be Ocular Motor, followed jointly by Gait/Midline and Daily Activities, then Limb Motor and Mentation, and finally Bulbar. For CBS, Limb Motor manifested first and ocular showed less probability of impairment throughout the disease spectrum. An online tool to visualize predicted disease progression was developed to predict relative disability on each subscale per overall disease severity. CONCLUSION: The PSP Rating Scale captures disease severity in both PSP and CBS. Modelling how domains change in relation to one other at varying disease severities may facilitate detection of therapeutic effects in future clinical trials
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