Robust estimation of stationary continuous-time ARMA models via indirect inference

In this paper we present a robust estimator for the parameters of a continuous-time ARMA(p,q) (CARMA(p,q)) process sampled equidistantly which is not necessarily Gaussian. Therefore, an indirect estimation procedure is used. It is an indirect estimation because we first estimate the parameters of the auxiliary AR(r) representation ($r\geq 2p-1$) of the sampled CARMA process using a generalized M- (GM-)estimator. Since the map which maps the parameters of the auxiliary AR(r) representation to the parameters of the CARMA process is not given explicitly, a separate simulation part is necessary where the parameters of the AR(r) representation are estimated from simulated CARMA processes. Then, the parameter which takes the minimum distance between the estimated AR parameters and the simulated AR parameters gives an estimator for the CARMA parameters. First, we show that under some standard assumptions the GM-estimator for the AR(r) parameters is consistent and asymptotically normally distributed. Next, we prove that the indirect estimator is consistent and asymptotically normally distributed as well using in the simulation part the asymptotically normally distributed LS-estimator. The indirect estimator satisfies several important robustness properties such as weak resistance, $\pi_{d_n}$-robustness and it has a bounded influence functional. The practical applicability of our method is demonstrated through a simulation study with replacement outliers and compared to the non-robust quasi-maximum-likelihood estimation method

Expression of human adenosine deaminase in nonhuman primates after retrovirus-mediated gene transfer.

Primate bone marrow cells were infected with a retroviral vector carrying the genes for human adenosine deaminase (h-ADA) and bacterial neomycin resistance (neor). The infected cells were infused back into the lethally irradiated donor animals. Several monkeys fully reconstituted and were shown to express the h-ADA and neor genes at low levels in their recirculating hematopoietic cells for short periods of time

Dynamic consolidation problems in saturated soils solved through u-w formulation in a LME meshfree framework

A meshfree numerical model, based on the principle of Local Maximum Entropy (LME), including a B-bar algorithm to avoid instabilities, is applied to solve axisymmetric consolidation problems in elastic saturated soils. This numerical scheme has been previously validated for purely elastic problems without water (mono phase), as well as for steady seepage in elastic porous media. Hereinafter, an implementation of the novel numerical method in the axisymmetric configuration is proposed, and the model is validated for well known theoretical problems of consolidation in saturated soils, under both static and dynamic conditions with available analytical solutions. The solutions obtained with the new methodology are compared with a finite element commercial software for a set of examples. After validated, solutions for dynamic radial consolidation and sinks, which have not been found elsewhere in the literature, are presented as a novelty. This new numerical approach is demonstrated to be feasible for this kind of problems in porous media, particularly for high frequency, dynamic problems, for which very few results have been found in the literature in spite of their high practical importance

Meshfree numerical schemes applied to seepage problems through earth dams

Modelling seepage along with the mechanical responses of deformable Earth Dams under transient conditions is a challenging task, since both coupling between different phases, and computation of free-surface variables are involved. In the present work, we take on the meshfree numerical schemes to establish a framework for solving coupled, transient problems for unconfined seepage through Earth Dams. The equations of Biot are formulated in displacement (or u − w formulation) assuming an elastic solid skeleton. Shape functions based on the principle of Maximum Entropy are implemented for the meshfree framework. The free surface location and its evolution in time, is obtained by interpolation of pore water pressures through the domain. Applications to benchmark problems are compared with available results in the literature. The preliminary simulations for steady flow conditions show promising results

An interstitial fluid transdermal extraction system for continuous glucose monitoring

A novel microfluidic system which is fabricated with five polydimethylsiloxane layers for interstitial fluid (ISF) extraction, collection, and measurement toward the application of continuous and real-time glucose monitoring is presented in this paper. The system consists of a micro vacuum generator for ISF transdermal extraction and fluid manipulation, micro chambers for the collection of ISF, micro pneumatic valves for fluid management, and a micro flow sensor for ISF volume measurement. Sequentially controlled by the pneumatic valves, the ISF extraction, collection, and volumetric measurement functions of the system were demonstrated using the stable vacuum generated by the integrated vacuum generator. Through low-frequency ultrasound pretreated full-thickness pig skin, the normal saline solution with different glucose concentrations was transdermally extracted, collected, and measured. The absolute error in the volume measurement of the transdermally extracted ISF analog was less than 0.05 μ L. The microfluidic system makes it possible to realize the clinical application of continuous glucose monitoring based on ISF transdermal extraction technology. © 2012 IEEE.published_or_final_versio

Effect of Cyclooxygenase(COX)-1 and COX-2 inhibition on furosemide-induced renal responses and isoform immunolocalization in the healthy cat kidney

BACKGROUND: The role of cyclooxygenase(COX)-1 and COX-2 in the saluretic and renin-angiotensin responses to loop diuretics in the cat is unknown. We propose in vivo characterisation of isoform roles in a furosemide model by administering non-steroidal anti-inflammatory drugs (NSAIDs) with differing selectivity profiles: robenacoxib (COX-2 selective) and ketoprofen (COX-1 selective). RESULTS: In this four period crossover study, we compared the effect of four treatments: placebo, robenacoxib once or twice daily and ketoprofen once daily concomitantly with furosemide in seven healthy cats. For each period, urine and blood samples were collected at baseline and within 48 h of treatment starting. Plasma renin activity (PRA), plasma and urinary aldosterone concentrations, glomerular filtration rate (GFR) and 24 h urinary volumes, electrolytes and eicosanoids (PGE(2), 6-keto-PGF1(α,) TxB(2)), renal injury biomarker excretions [N-acetyl-beta-D-glucosaminidase (NAG) and Gamma-Glutamyltransferase] were measured. Urine volume (24 h) and urinary sodium, chloride and calcium excretions increased from baseline with all treatments. Plasma creatinine increased with all treatments except placebo, whereas GFR was significantly decreased from baseline only with ketoprofen. PRA increased significantly with placebo and once daily robenacoxib and the increase was significantly higher with placebo compared to ketoprofen (10.5 ± 4.4 vs 4.9 ± 5.0 ng ml(−1) h(−1)). Urinary aldosterone excretion increased with all treatments but this increase was inhibited by 75 % with ketoprofen and 65 % with once daily robenacoxib compared to placebo. Urinary PGE(2) excretion decreased with all treatments and excretion was significantly lower with ketoprofen compared to placebo. Urinary TxB(2) excretion was significantly increased from baseline only with placebo. NAG increased from baseline with all treatments. Immunohistochemistry on post-mortem renal specimens, obtained from a different group of cats that died naturally of non-renal causes, suggested constitutive COX-1 and COX-2 co-localization in many renal structures including the macula densa (MD). CONCLUSIONS: These data suggest that both COX-1 and COX-2 could generate the signal from the MD to the renin secreting cells in cats exposed to furosemide. Co-localization of COX isoenzymes in MD cells supports the functional data reported here. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12917-015-0598-z) contains supplementary material, which is available to authorized users

Interactions in vivo between the Vif protein of HIV-1 and the precursor (Pr55GAG) of the virion nucleocapsid proteins

The abnormality of viral core structure seen in vif-defective HIV-1 grown in PBMCs has suggested a role for Vif in viral morphogenesis. Using an in vivo mammalian two-hybrid assay, the interaction between Vif and the precursor (Pr55GAG) of the virion nucleocapsid proteins has been analysed. This revealed the amino-terminal (aa 1–22) and central (aa 70–100) regions of Vif to be essential for its interaction with Pr55GAG, but deletion of the carboxy-terminal (aa 158–192) region of the protein had only a minor effect on its interaction. Initial deletion studies carried out on Pr55GAG showed that a 35-amino-acid region of the protein bridging the MA(p17)–CA(p24) junction was essential for its ability to interact with Vif. Site-directed mutagenesis of a conserved tryptophan (Trp21) near the amino terminus of Vif showed it to be important for the interaction with Pr55GAG. By contrast, mutagenesis of the highly conserved YLAL residues forming part of the BC-box motif, shown to be important in Vif promoting degradation of APOBEC3G/3F, had little or no effect on the Vif–Pr55GAG interaction

High Fidelity Tape Transfer Printing Based On Chemically Induced Adhesive Strength Modulation

Transfer printing, a two-step process (i.e. picking up and printing) for heterogeneous integration, has been widely exploited for the fabrication of functional electronics system. To ensure a reliable process, strong adhesion for picking up and weak or no adhesion for printing are required. However, it is challenging to meet the requirements of switchable stamp adhesion. Here we introduce a simple, high fidelity process, namely tape transfer printing(TTP), enabled by chemically induced dramatic modulation in tape adhesive strength. We describe the working mechanism of the adhesion modulation that governs this process and demonstrate the method by high fidelity tape transfer printing several types of materials and devices, including Si pellets arrays, photodetector arrays, and electromyography (EMG) sensors, from their preparation substrates to various alien substrates. High fidelity tape transfer printing of components onto curvilinear surfaces is also illustrated

TGF-beta(2)- and H2O2-Induced Biological Changes in Optic Nerve Head Astrocytes Are Reduced by the Antioxidant Alpha-Lipoic Acid

Background/Aims: The goal of the present study was to determine whether transforming growth factor-beta(2) (TGF-beta(2))- and oxidative stress-induced cellular changes in cultured human optic nerve head (ONH) astrocytes could be reduced by pretreatment with the antioxidant alpha-lipoic acid (LA). Methods: Cultured ONH astrocytes were treated with 1.0 ng/ml TGF-beta(2) for 24 h or 200 mu M hydrogen peroxide (H2O2) for 1 h. Lipid peroxidation was measured by a decrease in cis-pari-naric acid fluorescence. Additionally, cells were pretreated with different concentrations of LA before TGF-beta 2 or H2O2 exposure. Expressions of the heat shock protein (Hsp) alpha B-crystallin and Hsp27, the extracellular matrix (ECM) component fibronectin and the ECM-modulating protein connective tissue growth factor (CTGF) were examined with immunohistochemistry and real-time PCR analysis. Results: Both TGF-beta(2) and H2O2 increased lipid peroxidation. Treatment of astrocytes with TGF-beta(2) and H2O2 upregulated the expression of alpha B-crystallin, Hsp27, fibronectin and CTGF. Pretreatment with different concentrations of LA reduced the TGF-beta(2)- and H2O2-stimulated gene expressions. Conclusion: We showed that TGF-beta(2)- and H2O2-stimulated gene expressions could be prevented by pretreatment with the antioxidant LA in cultured human ONH astrocytes. Therefore, it is tempting to speculate that the use of antioxidants could have protective effects in glaucomatous optic neuropathy. Copyright (C) 2012 S. Karger AG, Base

On the use of the group SO(4,2) in atomic and molecular physics

In this paper the dynamical noninvariance group SO(4,2) for a hydrogen-like atom is derived through two different approaches. The first one is by an established traditional ascent process starting from the symmetry group SO(3). This approach is presented in a mathematically oriented original way with a special emphasis on maximally superintegrable systems, N-dimensional extension and little groups. The second approach is by a new symmetry descent process starting from the noninvariance dynamical group Sp(8,R) for a four-dimensional harmonic oscillator. It is based on the little known concept of a Lie algebra under constraints and corresponds in some sense to a symmetry breaking mechanism. This paper ends with a brief discussion of the interest of SO(4,2) for a new group-theoretical approach to the periodic table of chemical elements. In this connection, a general ongoing programme based on the use of a complete set of commuting operators is briefly described. It is believed that the present paper could be useful not only to the atomic and molecular community but also to people working in theoretical and mathematical physics.Comment: 31 page