23,462 research outputs found
COMMODITY PROGRAM SLIPPAGE RATES FOR CORN AND WHEAT
Slippage rates for corn and wheat are estimated using a simultaneous system explaining per-acre yields, input usage, technical change, and levels of participation in government programs. Soybeans are included due to cross-compliance requirements and because they substitute for corn in production. Slippage rates for wheat are in the range of 29-37% and for corn in the range of 48-58%. The results imply that efficient design of commodity programs must account for the slippage of aggregate yields due to changes in land quality and the use of constrained resources over fewer acres.Crop Production/Industries,
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Congenital imperforate hymen with hydrocolpos and hydronephrosis associated with severe hydramnios and increase of maternal ovarian steroidogenic enzymes
This is a clinical research paperStudy Objective: To study clinical features of patient presented with severe hydramnios, associated with hydronephrosis, that was antenatally diagnosed and has
been successfully treated immediately after birth. At a molecular level, we investigated the gene expression of key steroidogenic enzymes from the maternal ovary.
Design: Ultrasound scan,MRI, semi-quantitativeRT-PCR
Setting: The patient was admitted to the University Hospital,
University of Crete, Medical School, Greece, where
all clinical data has been obtained. Gene expression studies
took place at Biosciences, Brunel University, UK.
Results: Semi-quantitative RT-PCR analyses revealed
that there is upregulation of key steroidogenic genes in
the maternal ovary, including steroidogenic acute regulatory
protein, and the cytochrome P450 heme-containing
proteins CYP11A, CYP17 and CYP19. From a clinical perspective,
the prenatal ultrasound scan and MRI findings
showed a multicystic pelvic mass, bilateral hydronephrosis
and prior to delivery severe polyhydramnios.
Conclusion: This clinical case is the only one that we
have found in the current literature where congenital imperforate
hymen accompanied with hematocolpos is associated
with renal obstruction in combination with polyhydramnios
and increase in maternal steroidogenic enzymes
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Expression of membrane and nuclear progesterone receptors in two human placental choriocarcinoma cell lines (JEG-3 and BeWo): Effects of syncytialization
This article has been made available through the Brunel Open Access Publishing Fund and is available from the specified link -
Copyright @ 2011 Spandidos Publications Ltd.A vital function of the human placenta is to produce steroid hormones such as progesterone, which are essential for the maintenance of pregnancy and the onset of parturition. Although choriocarcinoma cell lines are valuable placental models for investigations of steroid hormone actions, little is known about the expression of progesterone receptors (PRs) in these cell lines. Therefore, in this study, the expression of membrane and nuclear PRs was investigated in cultures of fusigenic (BeWo) and non-fusigenic (JEG-3) human choriocarcinoma cell lines. In addition, the effects of an inducer of syncytialization (forskolin) on the PR expression in BeWo cells were assessed. Quantitative RT-PCR revealed that in fully syncytialized BeWo cells (treated with 50 mu M forskolin for 72 h) there was a significant down-regulation of mPR alpha and up-regulation of mPR beta and of the progesterone membrane component-1 (PGRMC1) when compared with non-syncytialized BeWo cells. Expression of all the mPR and PGRMC1 mRNAs was significantly lower in JEG-3 cells compared to non-syncytialized BeWo cells. Interestingly, expression of PR-B was unaltered between the two BeWo states but was significantly higher in JEG-3 cells. Immunofluorescence analysis revealed that mPR proteins are differentially expressed in these choriocarcinoma cell lines as well as in the human placenta. The data demonstrate that human choriocarcinoma cell lines have a complex system of progesterone signalling involving multiple classes of PRs. The finding that syncytialization is accompanied by changes in the expression of these receptors may suggest that this process influences progesterone signalling
Determination of Frequency and Distribution of Hessian Fly (Diptera: Cecidomyiidae) Biotypes in the Northeastern Soft Wheat Region
Fifteen collections of Hessian flies from the northern soft winter wheat region of the United States were used to determine the composition and frequency of biotypes. The wheat cultivars \u27Seneca\u27 (H7Hs), \u27Monon\u27 (H3), \u27Knox 62\u27 (~, H7Hg), and \u27Abe\u27 (Hs) were used as differentials. Biotypes J and L replaced biotype B as the prevalent biotype in Indiana, since wheat cultivars having the Hs and the H6 genes have been grown. Biotype GP, the least virulent of any Hessian fly biotypes, was still present in New York indicating that wheat cuItivars with no genes for resistance are still being grown there. The genetic variability of Hessian fly biotypes that enables them to overcome the resistance in wheat cultivars is discussed
Expression of mTOR and downstream signalling components in the JEG-3 and BeWo human placental choriocarcinoma cell lines
This article has been made available through the Brunel Open Access Publishing Fund.Emerging data suggest that nutritional status and body weight are related to reproductive function, and nutrient imbalances during pregnancy lead to changes in the expression of fetal genes. Recent studies show that the mTOR acts as a placental growth signalling sensor and its expression is down-regulated in intrauterine growth restriction. To date, very little is known about the expression of this signalling pathway in choriocarcinoma, one of the most lethal germ cell cancers. In this study, cultures of fusigenic (BeWo) and non-fusigenic (JEG-3) human choriocarcinoma cell lines were used to investigate the expression of mTOR and its downstream signalling components. The effects of an inducer of syncytialisation (forskolin) on mTOR, eIF4E binding proteins (4EBPs) and ribosomal protein S6 kinases (S6Ks) in BeWo cells were also assessed. RT-PCR studies revealed that mTOR, 4EBP and S6Ks are expressed at mRNA level in both JEG-3 and BeWo cells. Semi-quantitative RT-PCR analysis revealed that in early stages of syncytialisation (50 µM forskolin for 48 h), the expression of mTOR and 4EBP was down-regulated when compared to unstimulated cells. In fully syncytialised cells (50 µM forskolin for 72 h) the expression of both genes was similar to basal levels. Interestingly, the phosphorylation (Ser371, Thr389) status of p70S6K remained unaltered upon forskolin treatment. These data validate BeWo cells as an experimental model to study the effects of forskolin-induced syncytialisation on mTOR signalling.This article is available through the Brunel Open Access Publishing Fun
Conductivity of Paired Composite Fermions
We develop a phenomenological description of the nu=5/2 quantum Hall state in
which the Halperin-Lee-Read theory of the half-filled Landau level is combined
with a p-wave pairing interaction between composite fermions (CFs). The
electromagnetic response functions for the resulting mean-field superconducting
state of the CFs are calculated and used in an RPA calculation of the q and
omega dependent longitudinal conductivity of the physical electrons, a quantity
which can be measured experimentally
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Internalisation of membrane progesterone receptor-α after treatment with progesterone: Potential involvement of a clathrin-dependent pathway
This article has been made available through the Brunel Open Access Publishing Fund.Internalisation and recycling of seven trans-membrane domain receptors is a critical regulatory event for their signalling. The mechanism(s) by which membrane progesterone receptor-α (mPRα) number is regulated on the cell surface is unclear. In this study, we investigated the cellular distribution of mPRα and mechanisms of mPRα trafficking using a cell line derived from a primary culture of human myometrial cells (M11) as an experimental model. RT-PCR and immunofluorescent analysis demonstrated expression of mPRα in M11 cells with mPRα primarily distributed on the cell surface under basal conditions. For the first time, plasma membrane localisation of mPRα was confirmed using immuno-gold transmission electron microscopy. Stimulation of M11 cells with progesterone (P4, 100 nM) resulted in internalisation of mPRα from the plasma membrane to the cytoplasm (10 min) and subsequent partial translocation back to the cell surface (20 min). We investigated potential endocytotic pathways involved in trafficking of mPRα after its internalisation. Partial co-localisation of clathrin with mPRα was obvious after 10 min of P4 treatment. Of note, chlorpromazine (inhibitor of clathrin-mediated pathway) inhibited the endocytosis of mPRα, whereas treatment with nystatin (inhibitor of caveolae-mediated pathway) did not affect internalisation. Collectively, these data suggest that mPRα is expressed on the cell surface of M11 cells and undergoes endocytosis after P4 stimulation primarily via a clathrin-mediated pathway.This article is available through the Brunel Open Access Publishing Fun
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Differential expression of mTOR signalling components in drug resistance in ovarian cancer
This article has been made available through the Brunel Open Access Publishing Fund and is available from the specified link - Copyright @ 2010 The International Institute of Anticancer Research.Background/Aim: A limitation to successful cancer chemotherapy treatments is the acquisition of drug resistance. In advanced-stage ovarian cancer, the mammalian target of rapamycin (mTOR) pathway is upregulated, and inhibition of this pathway increases chemosensitivity in ovarian carcinoma cell lines. In this study, the expression of DEPTOR, mTOR, RICTOR, RAPTOR and S6 kinases were investigated in SKOV-3 and PEO1 parental and the paclitaxel-resistant (TaxR) SKOV-3TaxR and PEO1TaxR cell lines. Materials and Methods: RT-PCR, immunofluorescent analysis and Western blotting were carried out. Results: Quantitative RT-PCR revealed significant up-regulation of DEPTOR in both paclitaxel-resistant cell lines. SKOV-3TaxR exhibited down-regulation of RICTOR, RAPTOR and mTOR, whereas PEO1-TaxR showed down-regulation of RAPTOR and up-regulation of RICTOR and mTOR. Semi-quantitative RT-PCR analysis revealed marked changes in the expression of p70S6K splice variants mRNA in PEO1TaxR. Moreover, the phosphorylation status of p70S6K at Ser371 appears to be cell-type specific. Conclusion: We hypothesize that mTOR signalling may play a role in mediating paclitaxel resistance in ovarian cancer
M-grid: Using Ubiquitous Web Technologies to create a Computational Grid
There are many potential users and uses for grid computing. However, the concept of sharing computing resources excites security concerns and, whilst being powerful and flexible, at least for novices, existing systems are complex to install and use. Together these represent a significant barrier to potential users who are interested to see what grid computing can do. This paper describes m-grid, a system for building a computational grid which can accept tasks from any user with access to a web browser and distribute them to almost any machine with access to the internet and manages to do this without the installation of additional software or interfering with existing security arrangements
Clustering Phase Transitions and Hysteresis: Pitfalls in Constructing Network Ensembles
Ensembles of networks are used as null models in many applications. However,
simple null models often show much less clustering than their real-world
counterparts. In this paper, we study a model where clustering is enhanced by
means of a fugacity term as in the Strauss (or "triangle") model, but where the
degree sequence is strictly preserved -- thus maintaining the quenched
heterogeneity of nodes found in the original degree sequence. Similar models
had been proposed previously in [R. Milo et al., Science 298, 824 (2002)]. We
find that our model exhibits phase transitions as the fugacity is changed. For
regular graphs (identical degrees for all nodes) with degree k > 2 we find a
single first order transition. For all non-regular networks that we studied
(including Erdos - Renyi and scale-free networks) we find multiple jumps
resembling first order transitions, together with strong hysteresis. The latter
transitions are driven by the sudden emergence of "cluster cores": groups of
highly interconnected nodes with higher than average degrees. To study these
cluster cores visually, we introduce q-clique adjacency plots. We find that
these cluster cores constitute distinct communities which emerge spontaneously
from the triangle generating process. Finally, we point out that cluster cores
produce pitfalls when using the present (and similar) models as null models for
strongly clustered networks, due to the very strong hysteresis which
effectively leads to broken ergodicity on realistic time scales.Comment: 13 pages, 11 figure
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