162 research outputs found
Rethinking the Farm Revolt of the 1930s
The northern Plains witnessed the last great farm revolt in its history during the 1930s, when a flood of protest spilled across the region, fed by the springs of hard times and earlier insurgencies. The countryside, for one last moment, forced itself upon the rest of the country and demanded attention for its plight. After a period of high visibility, these efforts receded in the wake of New Deal programs that seemingly undercut the rural revolt. Many of the protesters arrived at an accommodation with the new regime, accepting half-aloof now in terms of wheat allotment checks and refinanced mortgages instead of pie-in-the- sky dreams of cost-of-production and the cooperative commonwealth. Some, of course, continued to resist the sirens of expediency and accommodation, at least a bit longer1 But most observers agreed that Depression era insurgency peaked in 1933 and had pretty much wound down by the 1936 election
Acidosis activates complement system in vitro.
We investigated the in vitro effect of different forms of acidosis (pH 7.0) on the formation of anaphylatoxins C3a and C5a. Metabolic acidosis due to addition of hydrochloric acid (10 micromol/ml blood) or lactic acid (5.5 micromol/ml) to heparin blood (N=12) caused significant activation of C3a and C5a compared to control (both p=0.002). Respiratory acidosis activated C3a (p=0.007) and C5a (p=0.003) compared to normocapnic controls. Making blood samples with lactic acidosis hypocapnic resulted in a median pH of 7.37. In this respiratory compensated metabolic acidosis, C3a and C5a were not increased. These experiments show that acidosis itself and not lactate trigger for activation of complement components C3 and C5
Diagnosis / Intervention criteria in damaged slabs by severe corrosion of prestressed joists
This research defines diagnosis criteria in R/C one-way slabs with severe corrosion at the lower prestressed reinforcement of the joists and proposes specific actuation criteria and constructive recommendations to increase the safety. The corrosion of this reinforcement is the most common damage in building structures, and the use of aluminous cement in the precast joists can aggravate the corrosion.
The usual cases of entire residential buildings with different degrees of damage and with a few or all joists affected in a slab have been simulated. ACI-318 is used as an acceptance criterion for existing structures in the simulations, and a ratio between the ultimate load and the service load is defined as valuation coefficient. By this way, the residual safety for a damaged structure is known.
Results are in accordance with the extensive experience in real intervention cases, which often still have high safety reserves.Vercher Sanchis, JM.; Gil Benso, E.; Mas Tomas, MDLA.; Lerma Elvira, C. (2013). Diagnosis / Intervention criteria in damaged slabs by severe corrosion of prestressed joists. Journal of Performance of Constructed Facilities. (04014040). doi:10.1061/(ASCE)CF.1943-5509.0000515S0401404
TNF-Ξ± induced endothelial MAdCAM-1 expression is regulated by exogenous, not endogenous nitric oxide
BACKGROUND: MAdCAM-1 is an adhesion molecule expressed in Peyer's patches and lymphoid tissues which is mobilized by cytokines like TNF-Ξ± and is a major determinant of lymphocyte trafficking to the gut in human inflammatory bowel disease (IBD). It has been suggested that both reactive oxygen and nitrogen metabolites participate in regulating adhesion molecule expression in response to TNF-Ξ±. METHODS: To examine how exogenous and endogenous sources of NO modulate MAdCAM-1 induction by TNF-Ξ±, we pre-treated mouse lymphatic endothelial cells with either long or short acting NO donors prior to TNF-Ξ±-stimulation, and measured MAdCAM-1 induction at 24 h. RESULTS AND DISCUSSION: DETA-NO, a long-acting NO donor, and SperNO, a rapid releasing NO donor both inhibited TNF-Ξ±-stimulated MAdCAM-1 expression in a concentration dependent manner. Both NO donors also reduced a4b7-dependent lymphocyte endothelial adhesion. Inhibition of endogenous NO production by either L-NAME, a non-selective NOS inhibitor, or by 1400 w, a selective iNOS inhibitor failed to induce, or potentiate TNF-Ξ± regulated MAdCAM-1 expression. CONCLUSIONS: Exogenous NO donors may be beneficial in the treatment of IBD, while endogenous nitric oxide synthases may be less effective in controlling adhesion molecule expression in response to cytokines
Potent and selective chemical probe of hypoxic signaling downstream of HIF-Ξ± hydroxylation via VHL inhibition
Chemical strategies to using small molecules to stimulate hypoxia inducible factors (HIFs) activity and trigger a hypoxic response under normoxic conditions, such as iron chelators and inhibitors of prolyl hydroxylase domain (PHD) enzymes, have broad-spectrum activities and off-target effects. Here we disclose VH298, a potent VHL inhibitor that stabilizes HIF-Ξ± and elicits a hypoxic response via a different mechanism, that is the blockade of the VHL:HIF-Ξ± protein-protein interaction downstream of HIF-Ξ± hydroxylation by PHD enzymes. We show that VH298 engages with high affinity and specificity with VHL as its only major cellular target, leading to selective on-target accumulation of hydroxylated HIF-Ξ± in a concentration- and time-dependent fashion in different cell lines, with subsequent upregulation of HIF-target genes at both mRNA and protein levels. VH298 represents a high-quality chemical probe of the HIF signalling cascade and an attractive starting point to the development of potential new therapeutics targeting hypoxia signalling
Increased oxidative metabolism following hypoxia in the type 2 diabetic heart, despite normal hypoxia signalling and metabolic adaptation
Hypoxia activates the hypoxia-inducible factor (HIF), promoting glycolysis and suppressing mitochondrial respiration. In the type 2 diabetic heart, glycolysis is suppressed whereas fatty acid metabolism is promoted. The diabetic heart experiences chronic hypoxia as a consequence of increased obstructive sleep apnoea and cardiovascular disease. Given the opposing metabolic effects of hypoxia and diabetes, we questioned whether diabetes affects cardiac metabolic adaptation to hypoxia. Control and type 2 diabetic rats were housed for 3 weeks in normoxia or 11% oxygen. Metabolism and function were measured in the isolated perfused heart using radiolabelled substrates. Following chronic hypoxia, both control and diabetic hearts upregulated glycolysis, lactate efflux and glycogen content and decreased fatty acid oxidation rates, with similar activation of HIF signalling pathways. However, hypoxia-induced changes were superimposed on diabetic hearts that were metabolically abnormal in normoxia, resulting in glycolytic rates 30% lower, and fatty acid oxidation 36% higher, in hypoxic diabetic hearts than hypoxic controls. Peroxisome proliferator-activated receptor Ξ± target proteins were suppressed by hypoxia, but activated by diabetes. Mitochondrial respiration in diabetic hearts was divergently activated following hypoxia compared with controls. These differences in metabolism were associated with decreased contractile recovery of the hypoxic diabetic heart following an acute hypoxic insult. In conclusion, type 2 diabetic hearts retain metabolic flexibility to adapt to hypoxia, with normal HIF signalling pathways. However, they are more dependent on oxidative metabolism following hypoxia due to abnormal normoxic metabolism, which was associated with a functional deficit in response to stress
Renal tubular HIF-2Ξ± expression requires VHL inactivation and causes fibrosis and cysts.
The Hypoxia-inducible transcription Factor (HIF) represents an important adaptive mechanism under hypoxia, whereas sustained activation may also have deleterious effects. HIF activity is determined by the oxygen regulated Ξ±-subunits HIF-1Ξ± or HIF-2Ξ±. Both are regulated by oxygen dependent degradation, which is controlled by the tumor suppressor "von Hippel-Lindau" (VHL), the gatekeeper of renal tubular growth control. HIF appears to play a particular role for the kidney, where renal EPO production, organ preservation from ischemia-reperfusion injury and renal tumorigenesis are prominent examples. Whereas HIF-1Ξ± is inducible in physiological renal mouse, rat and human tubular epithelia, HIF-2Ξ± is never detected in these cells, in any species. In contrast, distinct early lesions of biallelic VHL inactivation in kidneys of the hereditary VHL syndrome show strong HIF-2Ξ± expression. Furthermore, knockout of VHL in the mouse tubular apparatus enables HIF-2Ξ± expression. Continuous transgenic expression of HIF-2Ξ± by the Ksp-Cadherin promotor leads to renal fibrosis and insufficiency, next to multiple renal cysts. In conclusion, VHL appears to specifically repress HIF-2Ξ± in renal epithelia. Unphysiological expression of HIF-2Ξ± in tubular epithelia has deleterious effects. Our data are compatible with dedifferentiation of renal epithelial cells by sustained HIF-2Ξ± expression. However, HIF-2Ξ± overexpression alone is insufficient to induce tumors. Thus, our data bear implications for renal tumorigenesis, epithelial differentiation and renal repair mechanisms
Gender Differences in Early Reading Strategies: a Comparison of Synthetic Phonics Only with a Mixed Approach to Teaching Reading to 4-5 Year-Old Children
A survey of primary schools in England found that girls outperform boys in English across all phases (Ofsted in Moving English forward. Ofsted, Manchester, 2012). The gender gap remains an on-going issue in England, especially for reading attainment. This paper presents
evidence of gender differences in learning to read that
emerged during the development of a reading scheme for
4- and 5-year-old children in which 372 children from
Reception classes in sixteen schools participated in
12-month trials. There were three arms per trial: Intervention non-PD (non-phonically decodable text with mixed methods teaching); Intervention PD (phonically decodable text with mixed methods teaching); and a βbusiness as usualβ control condition SP (synthetic phonics and decodable text). Assignment to Intervention condition was randomised. Standardised measures of word reading and comprehension were used. The research provides statistically significant evidence suggesting that boys learn more easily using a mix of whole-word and synthetic phonics approaches. In addition, the evidence indicates that boys learn to read more easily using the natural-style language of βrealβ books including vocabulary which goes beyond their assumed decoding ability. At post-test, boys using the nonphonically decodable text with mixed methods (Intervention
A) were 8 months ahead in reading comprehension
compared to boys using a wholly synthetic phonics
approach
A Dialogue between the Hypoxia-Inducible Factor and the Tumor Microenvironment
The hypoxia-inducible factor is the key protein responsible for the cellular adaptation to low oxygen tension. This transcription factor becomes activated as a result of a drop in the partial pressure of oxygen, to hypoxic levels below 5% oxygen, and targets a panel of genes involved in maintenance of oxygen homeostasis. Hypoxia is a common characteristic of the microenvironment of solid tumors and, through activation of the hypoxia-inducible factor, is at the center of the growth dynamics of tumor cells. Not only does the microenvironment impact on the hypoxia-inducible factor but this factor impacts on microenvironmental features, such as pH, nutrient availability, metabolism and the extracellular matrix. In this review we discuss the influence the tumor environment has on the hypoxia-inducible factor and outline the role of this factor as a modulator of the microenvironment and as a powerful actor in tumor remodeling. From a fundamental research point of view the hypoxia-inducible factor is at the center of a signaling pathway that must be deciphered to fully understand the dynamics of the tumor microenvironment. From a translational and pharmacological research point of view the hypoxia-inducible factor and its induced downstream gene products may provide information on patient prognosis and offer promising targets that open perspectives for novel βanti-microenvironmentβ directed therapies
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