2,463 research outputs found

    Studies on the Life Cycle and Transmission of \u3ci\u3eCougourdella\u3c/i\u3e Sp., A Microsporidian Parasite of \u3ci\u3eGlossosoma Nigrior\u3c/i\u3e (Trichoptera: Glossosomatidae)

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    The trichopteran Glossosoma nigrior, the dominant benthic invertebrate grazer in Michigan trout streams, hosts a microsporidian (Protozoa) pathogen, Cougourdella sp., which strongly regulates the population density of larvae in the stream. In order to better understand the interactions between these two species, two possible modes of pathogen transmission, oral and transovum, were investigated. While both sexes of adult G. nigrior were found to be infected with mature environmental spores, spores were not found associated with reproductive tissue. This suggests that transovum transmission does not occur in this system. Glossosoma nigrior, when ex- posed to viable spores taken from infected larvae, did not produce Cougourdella sp. infections, which suggests that oral transmission also does not occur. It is possible that an intermediate host is required

    A New Microsporidium in Alfalfa Weevil Populations: Distribution and Characterization

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    A microsporidium species, not previously reported, was found infecting field populations of the alfalfa weevil, Hypera postica, in Illinois. The pathogen is widely distributed thoughout the state. Percent infection ranged from 1 % to 50% at different collection locations. Characteristics of the microsporidium and possible modes of transmission are presented

    Legal Resolution of Export Trade Disputes With the Roc

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    Gene expression during preimplantation mouse development

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    To develop a resource for the identification and isolation of genes expressed in the early mammalian embryo, large and representative cDNA libraries were constructed from unfertilized eggs, and two-cell, eight-cell, and blastocyst-stage mouse embryos. Using these libraries, we now report the first stages at which the cytokines interleukin (IL)-6, IL-1 beta, and interferon (IFN)-gamma are transcribed in the developing embryo and the presence of IL-7 transcripts in the unfertilized egg. Transcripts for IL-1 alpha, -2, -3, -4, or -5 were not detected at these stages. To identify novel genes expressed on activation of the embryonic genome, the egg and eight-cell stage-specific cDNA libraries were subtracted from the two-cell library, yielding a specialized cDNA library enriched for transcripts expressed at the two-cell stage. Sequence and Southern blot analysis of several of these cDNAs expressed predominantly at the two-cell stage of embryogenesis revealed them to be from novel genes, thereby providing the first molecular tools with which to approach the study of gene expression in the early mammalian embryo

    Modeling attacks on physical unclonable functions

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    We show in this paper how several proposed Physical Unclonable Functions (PUFs) can be broken by numerical modeling attacks. Given a set of challenge-response pairs (CRPs) of a PUF, our attacks construct a computer algorithm which behaves indistinguishably from the original PUF on almost all CRPs. This algorithm can subsequently impersonate the PUF, and can be cloned and distributed arbitrarily. This breaks the security of essentially all applications and protocols that are based on the respective PUF. The PUFs we attacked successfully include standard Arbited PUFs and Ring Oscillator PUFs of arbitrary sizes, and XO Arbiter PUFs, Lightweight Secure PUFs, and Feed-Forward Arbiter PUFs of up to a given size and complexity. Our attacks are based upon various machine learning techniques including Logistic Regression and Evolution Strategies. Our work leads to new design requirements for secure electrical PUFs, and will be useful to PUF designers and attackers alike.Technische Universitat Munche

    PUF Modeling Attacks on Simulated and Silicon Data

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    We discuss numerical modeling attacks on several proposed strong physical unclonable functions (PUFs). Given a set of challenge-response pairs (CRPs) of a Strong PUF, the goal of our attacks is to construct a computer algorithm which behaves indistinguishably from the original PUF on almost all CRPs. If successful, this algorithm can subsequently impersonate the Strong PUF, and can be cloned and distributed arbitrarily. It breaks the security of any applications that rest on the Strong PUF's unpredictability and physical unclonability. Our method is less relevant for other PUF types such as Weak PUFs. The Strong PUFs that we could attack successfully include standard Arbiter PUFs of essentially arbitrary sizes, and XOR Arbiter PUFs, Lightweight Secure PUFs, and Feed-Forward Arbiter PUFs up to certain sizes and complexities. We also investigate the hardness of certain Ring Oscillator PUF architectures in typical Strong PUF applications. Our attacks are based upon various machine learning techniques, including a specially tailored variant of logistic regression and evolution strategies. Our results are mostly obtained on CRPs from numerical simulations that use established digital models of the respective PUFs. For a subset of the considered PUFs-namely standard Arbiter PUFs and XOR Arbiter PUFs-we also lead proofs of concept on silicon data from both FPGAs and ASICs. Over four million silicon CRPs are used in this process. The performance on silicon CRPs is very close to simulated CRPs, confirming a conjecture from earlier versions of this work. Our findings lead to new design requirements for secure electrical Strong PUFs, and will be useful to PUF designers and attackers alike.National Science Foundation (U.S.) (Grant CNS 0923313)National Science Foundation (U.S.) (Grant CNS 0964641

    Tireotropin i hormoni štitnjače u eutireoidnom Hashimotovu tireoiditisu

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    Little is known about thyrotropin (TSH) and thyroid hormones in euthyroid Hashimoto’s thyroiditis (HT), thus the aim was to investigate TSH and thyroid hormone economy in euthyroid HT and its relation to thyroid function. Ninety-five patients with euthyroid HT with normal TSH and thyroid hormones on the last follow up between 2009 and 2011 were investigated. Previous observation period ranged from 1.5 to 4.8 (mean 2.8) years, and they had never been treated with levothyroxine. The results of TSH and thyroid hormones were compared with 210 healthy subjects and expressed as median (25%-75%). According to TSH value, the subjects were divided into quartiles: TSH 0.4-0.99 (1q), 1.0-1.99 (2q), 2.0-2.99 (3q) and 3.0-4.0 mIU /L (4q). Euthyroid HT patients had higher TSH (2.53 [1.79-3.14] vs.1.95 [1.24-2.72], p<0.001). T4 and T3 were not different. The distribution of TSH in HT patients was significantly shifted to the right; 71% of patients were in the 3q and 4q groups. When HT patients with higher TSH (3q and 4q) were compared with those with lower TSH (1q and 2q), significant differences emerged in TSH (3.01 [2.48-3.48] vs.1.45 [1.07-1.71] mIU /L), T4 (99.0 [88.2-112.0] vs.112.0 [105.0-122.0] nmol/L) and T3 (1.78 [1.48-2.05] vs. 2.10 [1.85-2.21] nmol/L; p<0.01). TPO values were similar in both groups. A gradually increasing proportion of euthyroid HT patients with at least one supranormal TSH during the observation period were found: 0% in 1q, 10% in 2q, 15% in 3q and 44% in 4q TSH group. Euthyroid HT patients maintain euthyroidism only under strenuous TSH stimulation. The patients with high normal TSH are identified as those with a major risk of hypothyroidism in the near future.Malo je poznato o vrijednostima tireoptropina (TSH) i hormona štitnjače u eutireoidnom Hashimotovu tireoiditisu (HT) te je cilj bio istražiti razinu TSH i hormona štitnjače u HT i njihov odnos prema funkciji štitnjače. Ispitano je 95 bolesnika s eutireoidnim HT s normalnim TSH i hormonima štitnjače na posljednjoj kontroli između 2009. i 2011. godine. Prethodno razdoblje promatranja variralo je od 1,5 do 4,8 (u prosjeku 2,8) godina, bolesnici nisu nikada liječeni levotiroksinom. Rezultati TSH i hormona štitnjače uspoređeni su s onima u 210 zdravih osoba i prikazani kao medijan (25%-75%). Prema vrijednosti TSH ispitanici su podijeljeni u kvartile: TSH 0,4-0,99 (1q), 1,0-1,99 (2q), 2,0-2,99 (3q) i 3,0-4,0 mIU /L (4q). Eutireoidni bolesnici s HT imali su viši TSH (2,53 [1,79-3,14] prema 1,95 [1,24-2,72], p<0,001). T4 i T3 se nisu razlikovali. Raspodjela TSH u HT izrazito je pomaknuta udesno. Ukupno je 71% bolesnika bilo u skupini 3q i 4q. Kada se usporede HT bolesnici s višim (3q i 4q) i nižim TSH (1q i 2q) nalaze se značajne razlike u TSH (3,01 [2,48-3,48] prema 1,45 [1,07-1,71] mIU /L), T4 (99,0 [88,2-112,0] prema 112,0 [105,0-122,0] nmol/L) i T3 (1,78 [1,48- 2,05] prema 2,10 [1,85-2,21] nmol/L; p<0,01). Vrijednosti TPO bile su slične u obje skupine HT bolesnika. Opažen je postupni porast postotka eutireoidnih HT bolesnika s najmanje jednom povišenom vrijednošću TSH tijekom razdoblja promatranja: 0% u skupini 1q, 10% u 2q, 15% in 3q i 44% u skupini 4q. Eutireoidni bolesnici s HT održavaju eutireozu jedino uz povećanu stimulaciju pomoću TSH. Bolesnici s visoko normalnim TSH imaju najveći rizik nastupa hipotireoze u bliskoj budućnosti

    Monitoring the response of canine hyperadrenocorticism to trilostane treatment by assessment of acute phase protein concentrations

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    &lt;b&gt;Background&lt;/b&gt;: Acute phase proteins (APPS) include haptoglobin (Hp), C-reactive protein (CRP) and serum amyloid A (SAA). Increased Hp concentrations may be induced by endogenous or exogenous glucocorticoids in dogs. &lt;b&gt;Objectives&lt;/b&gt;: To assess whether control of hyperadrenocorticism (HAC) affects the concentrations of Hp, CRP, SAA, alkaline phosphatase (ALKP) and cholesterol, to determine whether these analytes can be used to assess control of HAC following trilostane treatment, and whether a combination of these tests offers a valid method of assessing disease control. &lt;b&gt;Methods&lt;/b&gt;: Hp, CRP, SAA, ALKP and cholesterol were assessed in 11 dogs with spontaneous HAC before and after treatment with trilostane. Adequate control of HAC was defined as post-ACTH cortisol less than 150 nmol/l. &lt;b&gt;Results&lt;/b&gt;: Significant reductions in Hp, ALKP, cholesterol and SAA (P&#60;0·05) but not of CRP were found after control of HAC. Only Hp, cholesterol and ALKP were moderately informative (Se &#38; Sp&#62;0·7) of disease control when compared to adrenocorticotropin or corticotropin (ACTH) stimulation test. SAA and CRP were unhelpful (Se &#38; Sp&#60;0·7). The analysis of the combination of the analytes did not improve the correlation with ACTH stimulation test. &lt;b&gt;Clinical Relevance&lt;/b&gt;: Relying on these analytes does not provide additional information over ACTH stimulation test results when assessing control of HAC treated with trilostane

    Thermal diffusivity measurements of metastable austenite during continuous cooling

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    The thermal diffusivity of the metastable undercooled austenite is relevant for the quantitative analysis of the carbon and low-alloy steel quench. The standard laser-flash method requires prior thermal equilibrium between the sample and the furnace, which may not be possible to achieve without allowing the metastable phase to transform. Nevertheless, depending upon the steel's hardenability, the thermal transient due to a laser pulse may be much shorter than a cooling transient sufficiently steep to prevent the transformation of the austenite. In one such case, flash measurements were performed during continuous sample cooling and the thermal diffusivity of the metastable austenite was determined by using an extension of the standard analytical model. The adopted analytical model and data reduction procedure are described and the limitations and uncertainties of this method are discussed, also with the aid of a non-linear numerical simulation. The measured thermal diffusivity of the under cooled low-alloy austenite decreases linearly from 5.4•10−6 m2 s−1 at 1133 K to 4.3•10−6 m2 s−1 at 755 K; this trend is in broad agreement with one previous set of measurements upon a low-alloy undercooled austenite and with a large number of previous standard measurements upon stable (high-alloy) austenitic stainless steels
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