329 research outputs found

    Introduction and evaluation of the wood preservative potentials of the poisonous Sternbergia candidum extracts

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    The ability of Sternbergia candida (SB Candidum Mathew.) extract to suppress attack by Postia placenta (Fries) M. Larsen et Lombard (Mad 698), (a brown-rot) and Trametes versicolor (L.ex Fr.) Quel.(a white-rot) was investigated. The extract was dissolved from Sterinbergia Candidum’s bulb and leaves in 96% ethyl alcohol. Poisonous extract impregnated into wood blocks of Turkish oriental beech (Fagus orientalis L.) and Scots pine (Pinus sylvestris L.). Extract dosages were 0.25, 0.75, 1.50 and 3.00%. Treated blocks were exposed to P. placenta and T. versicolor attack for 12 weeks by the soil block method. Only extract dosages of 0.25 and 0.75% were found efficacious in suppressing attack. A tukey studentized test found both dosages significant at 5% level. In conclusion, the poisonous extracts could be used as effective wood preservative when concentration was adjusted

    Zac1 functions through TGFβII to negatively regulate cell number in the developing retina

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    <p>Abstract</p> <p>Background</p> <p>Organs are programmed to acquire a particular size during development, but the regulatory mechanisms that dictate when dividing progenitor cells should permanently exit the cell cycle and stop producing additional daughter cells are poorly understood. In differentiated tissues, tumor suppressor genes maintain a constant cell number and intact tissue architecture by controlling proliferation, apoptosis and cell dispersal. Here we report a similar role for two tumor suppressor genes, the <it>Zac1 </it>zinc finger transcription factor and that encoding the cytokine TGFβII, in the developing retina.</p> <p>Results</p> <p>Using loss and gain-of-function approaches, we show that <it>Zac1 </it>is an essential negative regulator of retinal size. <it>Zac1 </it>mutants develop hypercellular retinae due to increased progenitor cell proliferation and reduced apoptosis at late developmental stages. Consequently, supernumerary rod photoreceptors and amacrine cells are generated, the latter of which form an ectopic cellular layer, while other retinal cells are present in their normal number and location. Strikingly, <it>Zac1 </it>functions as a direct negative regulator of a rod fate, while acting cell non-autonomously to modulate amacrine cell number. We implicate TGFβII, another tumor suppressor and cytokine, as a <it>Zac1</it>-dependent amacrine cell negative feedback signal. TGFβII and phospho-Smad2/3, its downstream effector, are expressed at reduced levels in <it>Zac1 </it>mutant retinae, and exogenous TGFβII relieves the mutant amacrine cell phenotype. Moreover, treatment of wild-type retinae with a soluble TGFβ inhibitor and TGFβ receptor II (TGFβRII) conditional mutants generate excess amacrine cells, phenocopying the <it>Zac1 </it>mutant phenotype.</p> <p>Conclusion</p> <p>We show here that <it>Zac1 </it>has an essential role in cell number control during retinal development, akin to its role in tumor surveillance in mature tissues. Furthermore, we demonstrate that <it>Zac1 </it>employs a novel cell non-autonomous strategy to regulate amacrine cell number, acting in cooperation with a second tumor suppressor gene, <it>TGFβII</it>, through a negative feedback pathway. This raises the intriguing possibility that tumorigenicity may also be associated with the loss of feedback inhibition in mature tissues.</p

    Optimal coordination of TCSC and PSS2B controllers in electric power systems using MOPSO multiobjective algorithm

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    Oscillations are an intrinsic phenomenon in interconnected power systems, leading to steady-state stability, safety decline, transmission power limitation, and electric power systems’ ineffective exploitation by developing power systems, particularly by connecting these systems to low-load lines. In addition, they affect the economic performance of the systems. In this study, PSS2B power system stabilizers and TCSC compensators are used to improve the stability margin of power systems. In order to coordinate TCSC compensators, the MOPSO multiobjective algorithm with integral of the time-weighted absolute error (ITAE) and figure of demerit (FD) objective functions was used. The MOPSO algorithm optimization results are compared with nondominated sorting genetic algorithm (NSGAII) and multiobjective differential evolution (MODE) algorithms. The optimization results indicated a better performance of the proposed MOPSO algorithm than NSGAII and MODE. The simulations were iterated in two scenarios by creating different loading conditions in generators. The results indicated that the proposed control system, where the coordination between PSS2B power system stabilizers and TCSC compensators using the MOPSO algorithm, is better than power systems in which PSS2B Stabilizers or TCSC compensators are utilized solely. All criteria, e.g., ITAE, FD, maximum deviation range, and the required time for power oscillation damping in hybrid control systems, have been obtained. This means more stability and accurate and proper performance

    Orientation Effects in Ballistic High-Strained P-type Si Nanowire FETs

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    In order to design and optimize high-sensitivity silicon nanowire-field-effect transistor (SiNW FET) pressure sensors, this paper investigates the effects of channel orientations and the uniaxial stress on the ballistic hole transport properties of a strongly quantized SiNW FET placed near the high stress regions of the pressure sensors. A discrete stress-dependent six-band k.p method is used for subband structure calculation, coupled to a two-dimensional Poisson solver for electrostatics. A semi-classical ballistic FET model is then used to evaluate the ballistic current-voltage characteristics of SiNW FETs with and without strain. Our results presented here indicate that [110] is the optimum orientation for the p-type SiNW FETs and sensors. For the ultra-scaled 2.2 nm square SiNW, due to the limit of strong quantum confinement, the effect of the uniaxial stress on the magnitude of ballistic drive current is too small to be considered, except for the [100] orientation. However, for larger 5 nm square SiNW transistors with various transport orientations, the uniaxial tensile stress obviously alters the ballistic performance, while the uniaxial compressive stress slightly changes the ballistic hole current. Furthermore, the competition of injection velocity and carrier density related to the effective hole masses is found to play a critical role in determining the performance of the nanotransistors

    Evaluation of the ICT Tuberculosis test for the routine diagnosis of tuberculosis

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    BACKGROUND: Rapid and accurate diagnosis of tuberculosis (TB) is crucial to facilitate early treatment of infectious cases and thus to reduce its spread. To improve the diagnosis of TB, more rapid diagnostic techniques such as antibody detection methods including enzyme-linked immunosorbent assay (ELISA)-based serological tests and immunochromatographic methods were developed. This study was designed to evaluate the validity of an immunochromatographic assay, ICT Tuberculosis test for the serologic diagnosis of TB in Antalya, Turkey. METHODS: Sera from 72 patients with active pulmonary (53 smear-positive and 19 smear-negative cases) and eight extrapulmonary (6 smear-positive and 2 smear-negative cases) TB, and 54 controls from different outpatient clinics with similar demographic characteristics as patients were tested by ICT Tuberculosis test. RESULTS: The sensitivity, specificity, and negative predictive value of the ICT Tuberculosis test for pulmonary TB were 33.3%, 100%, and 52.9%, respectively. Smear-positive pulmonary TB patients showed a higher positivity rate for antibodies than smear-negative patients, but the difference was not statistically significant. Of the eight patients with extrapulmonary TB, antibody was detected in four patients. CONCLUSION: Our results suggest that ICT Tuberculosis test can be used to aid TB diagnosis in smear-positive patients until the culture results are available

    Genetic and phenotypic characterization of NKX6‐2‐related spastic ataxia and hypomyelination

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    Background and purpose Hypomyelinating leukodystrophies are a heterogeneous group of genetic disorders with a wide spectrum of phenotypes and a high rate of genetically unsolved cases. Bi‐allelic mutations in NKX6‐2 were recently linked to spastic ataxia 8 with hypomyelinating leukodystrophy. Methods Using a combination of homozygosity mapping, exome sequencing, and detailed clinical and neuroimaging assessment a series of new NKX6‐2 mutations in a multicentre setting is described. Then, all reported NKX6‐2 mutations and those identified in this study were combined and an in‐depth analysis of NKX6‐2‐related disease spectrum was provided. Results Eleven new cases from eight families of different ethnic backgrounds carrying compound heterozygous and homozygous pathogenic variants in NKX6‐2 were identified, evidencing a high NKX6‐2 mutation burden in the hypomyelinating leukodystrophy disease spectrum. Our data reveal a phenotype spectrum with neonatal onset, global psychomotor delay and worse prognosis at the severe end and a childhood onset with mainly motor phenotype at the milder end. The phenotypic and neuroimaging expression in NKX6‐2 is described and it is shown that phenotypes with epilepsy in the absence of overt hypomyelination and diffuse hypomyelination without seizures can occur. Conclusions NKX6‐2 mutations should be considered in patients with autosomal recessive, very early onset of nystagmus, cerebellar ataxia with hypotonia that rapidly progresses to spasticity, particularly when associated with neuroimaging signs of hypomyelination. Therefore, it is recommended that NXK6‐2 should be included in hypomyelinating leukodystrophy and spastic ataxia diagnostic panels

    A requirement for filopodia extension toward Slit during Robo-mediated axon repulsion

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    Axons navigate long distances through complex 3D environments to interconnect the nervous system during development. Although the precise spatiotemporal effects of most axon guidance cues remain poorly characterized, a prevailing model posits that attractive guidance cues stimulate actin polymerization in neuronal growth cones whereas repulsive cues induce actin disassembly. Contrary to this model, we find that the repulsive guidance cue Slit stimulates the formation and elongation of actin-based filopodia from mouse dorsal root ganglion growth cones. Surprisingly, filopodia form and elongate toward sources of Slit, a response that we find is required for subsequent axonal repulsion away from Slit. Mechanistically, Slit evokes changes in filopodium dynamics by increasing direct binding of its receptor, Robo, to members of the actin-regulatory Ena/VASP family. Perturbing filopodium dynamics pharmacologically or genetically disrupts Slit-mediated repulsion and produces severe axon guidance defects in vivo. Thus, Slit locally stimulates directional filopodial extension, a process that is required for subsequent axonal repulsion downstream of the Robo receptor.National Institutes of Health (U.S.) (Grant F32-CA165700)National Institutes of Health (U.S.) (Grant R01-GM068678)National Institutes of Health (U.S.) (Grant P30-CA014051

    p16INK4A Positively Regulates Cyclin D1 and E2F1 through Negative Control of AUF1

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    /pRB/E2F pathway, a key regulator of the critical G1 to S phase transition of the cell cycle, is universally disrupted in human cancer. However, the precise function of the different members of this pathway and their functional interplay are still not well defined. -dependent manner, and several of these genes are also members of the AUF1 and E2F1 regulons. We also present evidence that E2F1 mediates p16-dependent regulation of several pro- and anti-apoptotic proteins, and the consequent induction of spontaneous as well as doxorubicin-induced apoptosis. is also a modulator of transcription and apoptosis through controlling the expression of two major transcription regulators, AUF1 and E2F1

    A Balance of BMP and Notch Activity Regulates Neurogenesis and Olfactory Nerve Formation

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    Although the function of the adult olfactory system has been thoroughly studied, the molecular mechanisms regulating the initial formation of the olfactory nerve, the first cranial nerve, remain poorly defined. Here, we provide evidence that both modulated Notch and bone morphogenetic protein (BMP) signaling affect the generation of neurons in the olfactory epithelium and reduce the number of migratory neurons, so called epithelioid cells. We show that this reduction of epithelial and migratory neurons is followed by a subsequent failure or complete absence of olfactory nerve formation. These data provide new insights into the early generation of neurons in the olfactory epithelium and the initial formation of the olfactory nerve tract. Our results present a novel mechanism in which BMP signals negatively affect Notch activity in a dominant manner in the olfactory epithelium, thereby regulating neurogenesis and explain why a balance of BMP and Notch activity is critical for the generation of neurons and proper development of the olfactory nerve

    Functions of long non-coding RNAs in human disease and their conservation in Drosophila development

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    Genomic analysis has found that the transcriptome in both humans and Drosophila melanogaster features large numbers of long non-coding RNA transcripts (lncRNAs). This recently discovered class of RNAs regulates gene expression in diverse ways and has been involved in a large variety of important biological functions. Importantly, an increasing number of lncRNAs have also been associated with a range of human diseases, including cancer. Comparative analyses of their functions among these organisms suggest that some of their modes of action appear to be conserved. This highlights the importance of model organisms such as Drosophila, which shares many gene regulatory networks with humans, in understanding lncRNA function and its possible impact in human health. This review discusses some known functions and mechanisms of action of lncRNAs and their implication in human diseases, together with their functional conservation and relevance in Drosophila development
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