998 research outputs found

    An Open Inflationary Model for Dimensional Reduction and its Effects on the Observable Parameters of the Universe

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    Assuming that higher dimensions existed in the early stages of the universe where the evolution was inflationary, we construct an open, singularity-free, spatially homogeneous and isotropic cosmological model to study the effects of dimensional reduction that may have taken place during the early stages of the universe. We consider dimensional reduction to take place in a stepwise manner and interpret each step as a phase transition. By imposing suitable boundary conditions we trace their effects on the present day parameters of the universe.Comment: 5 pages, accepted for publication in Int. J. of Mod. Phys.

    Functional involvement of γ-secretase in signaling of the triggering receptor expressed on myeloid cells-2 (TREM2).

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    BACKGROUND: Triggering receptor expressed on myeloid cells-2 (TREM2) exerts important functions in the regulation of monocytes, like dendritic cells, osteoclasts, tissue macrophages, and microglia. Mutations in TREM2 are associated with several diseases, including Nasu-Hakola disease, frontotemporal dementia, and Alzheimer's disease (AD). TREM2 undergoes sequential proteolytic processing by ectodomain shedding and intramembrane proteolysis. FINDINGS: We show that inhibition of γ-secretase-dependent cleavage of the TREM2 C-terminal fragment in cellular membranes interferes with TREM2-dependent signaling and cellular function. Inhibition of γ-secretase decreases membrane-proximal signaling and intracellular Ca(2+) response. Decreased signaling alters morphological changes and phagocytic activity of cells upon selective stimulation of TREM2. CONCLUSIONS: The data demonstrate the importance of γ-secretase-dependent intramembrane processing in TREM2-mediated signaling and, thus, a functional relation of two AD-associated proteins

    Age-specific life tables of Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae) and its parasitoid Aphytismelinus DeBach (Hymenoptera: Aphelinidae)

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    Abstract: Biological parameters of the California red scale (Aonidiella aurantii [Maskell] [Hemiptera: Diaspididae]) were determined under laboratory conditions at 3 different temperatures (20, 23, and 27 °C) on butternut squash (Cucurbita moschata Duchesne ex Lamarck) (Cucurbitaceae), while the biological parameters of its parasitoid Aphytis melinus DeBach (Hymenoptera: Aphelinidae) were conducted at 27 °C. The survival of A. aurantii ranged between 80.0% and 88.3%. The highest mortality was recorded during the adult stage, with mortalities ranging between 12% and 20%. On C. moschata, the total development time was 93.1 ± 9.73, 81.8 ± 7.13, and 65.7 ± 6.37 days, while the adult longevity was 54.65 ± 0.71, 47.05 ± 0.97, and 39.35 ± 1.07 days at 20, 23, and 27 °C, respectively. The oviposition period of A. aurantii was 44.3 ± 0.51, 40.65 ± 0.41, and 34.5 ± 0.45 days at 20, 23, and 27 °C, respectively. Average fecundity was 73.25 ± 1.827, 109.7 ± 3.569, and 129.35 ± 4.564 individuals at 20, 23, and 27 °C, respectively. For A. melinus, adult longevity was 19.24 ± 0.73 days, and average fecundity 62.7 ± 2.81 eggs at 27 °C. The preoviposition period was 0.82 ± 0.05 days, oviposition period was 15.7 ± 0.52 days, and postoviposition period was 2.21 ± 0.09 days. The intrinsic rate of increase (rm) of A. melinus (0.188 ♀/♀/day) was significantly greater than that of A. aurantii (0.080) at 27 °C. These laboratory results demonstrated that A. melinus is an effective parasitoid for decreasing A. aurantii populations. Fecundity of A. aurantii and A. melinus was determined with the Enkegaard equation. The best-fit parameters of fecundity were calculated as a = 0.410, b = 0.099; a = 0.624, b = 0.098; a = 0.661, b = 0.091; a = 1.190, b = 0.179 for A. aurantii at 20, 23, and 27 °C, and A. melinus at 27 °C, respectively

    Large Inverse Magnetic Entropy Changes and Magnetoresistance in the Vicinity of a Field-Induced Martensitic Transformation in Ni50−xCoxMn32−yFeyGa18

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    Significantly large inverse magnetic entropy changes (ΔSM) and magnetoresistance (MR) were observed at the inverse martensitic phase transitions of the Ga-based magnetic shape memory Heusler alloys: Ni50−xCoxMn32−yFeyGa18. The crystal structures of alloys were tetragonal at 300 K and the phase transition temperatures and magnetic properties were found to be correlated with the degree of tetragonal distortion. The maximum peak values of the ΔSM and MR at H = 5 T were determined as ≈ (+)31 J Kg−1 K−1 and ≈−21%, respectively, for x = 8 and y = 2. The relatively small hysteretic loss and large refrigeration capacity observed in this system make these compounds promising materials for applications

    Effect of Ankaferd Blood Stopper on Early Bone Tissue Healing in Extraction Sockets: An Experimental In vivo Study

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    Purpose: To investigate the effect of Ankaferd blood stopper (ABS) on early bone healing of extraction sockets in rats.Method: Twenty-eight male Wistar rats were divided into four groups. The maxillary right first molar tooth of the rats was extracted under general anesthesia. Two groups (C-1, n = 6 and C-2, n = 6) received saline solutions in the extraction sockets immediately and one day after the extraction, respectively, while two groups (A-1, n = 8 and A-2, n = 8) received ABS. The rats in A-1 and C-1 groups were sacrificed after 7 days of post-extraction while the rats in A-2 and C-2 groups were sacrificed after 28 days. Bone samples were taken from the maxillas, and tissues were prepared for histopathological analysis. Osteoid tissue (OT), mineralized bone tissue (MT), remaining area (RA), and inflammatory cell infiltration (ICI) were determined. The histomorphometric results were analyzed statistically using analysis of variance (ANOVA).Results Osteoid formation was highest in C-1 group (39.71 ± 9.68, p < 0.05). Differences in OT among other groups were not significant (p > 0.05). MT was higher in C-2 group (47.73 ± 12.15) than in other groups (p < 0.05). RA was highest in C-1 group (59.95 ± 12.75). ICI was significantly lower in control (C1 and C-2) groups than in ABS (A-1 and A-2) groups (p < 0.05).Conclusion: ABS administered topically to extraction sockets immediately after extraction has no effect on bone healing; in fact, ABS increases inflammation in vivo

    Fiğ+Arpa Karışımlarında Gübrelemenin Otun Verim ve Kimyasal Kompozisyonuna Etkisi

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    Bu araşt ı rma, Van koş ullar ı nda değişik dozlarda azot 0 ve 6 kg N / da ve fosforlu 0, 4, 8, 12 kg P 205 / da gübrelemenin fi ğ +arpa Vicia villosa spp. dasycarpa+ Hordeum vulgare L. kar ışı m ı nda, kuru ot verimi ve kimyasal kompozisyona etkilerini belirlemek amac ı ile yürütülmü ştür. Azotlu gübreleme, kar ışı m ı n yaş ve kuru ot verimi ile bitki boyu, otun N ve P içeriklerini önemli olarak art ı rı rken, botanik kompozisyondaki fiğ oran ı n ı azaltm ıştı r. Fosforlu gübreleme ise kar ışı m ı n yaş ve kuru ot verimleri ile N ve P içeriklerini önemli olarak art ı rm ışlard ı r. Kaliteli ve yüksek ot verimi için fi ğ+arpa kar ışı m ı na, bu koşullarda tesis gübrelemesi olarak dekara 6 kg N ve 8-12 kg fosforlu gübre verilmesi önerilebilir. Bitki analizleri sonucunda, kar ışı mdaki otun P, K, Ca, Mg, Zn ve Mn içerikleri hayvan beslemesi aç ı s ı ndan yeterli düzeyde bulunmu ştur
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