Based on cross-section data, this paper explores the relationship between economic freedom and the economic performance of low, middle and high income countries. The regression results show that there is a direct relationship between the economic freedom index and per capita income in low income countries and all countries as a whole. The evidence also indicates that there is a direct relationship between the economic freedom index and the growth rate of per capita income in high income countries and all countries as a whole.
Alzheimer's disease (AD) is a debilitating dementia characterized by progressive memory loss and aggregation of amyloid-b (Ab) protein into amyloid plaques in patient brains. Mutations in presenilin (PS) lead to abnormal generation of Ab, which is the major cause of familial AD (FAD), and apolipoprotein E4 (ApoE4) is the major genetic risk factor for sporadic AD (SAD) onset. However, whether dysfunction of PS is involved in the pathogenesis of SAD is largely unknown. We found that ApoE secretion was completely abolished in PS-deficient cells and markedly decreased by inhibition of c-secretase activity. Blockade of c-secretase activity by a c-secretase inhibitor, DAPT, decreased ApoE secretion, suggesting an important role of c-secretase activity in ApoE secretion. Reduced ApoE secretion is also observed in nicastrin-deficient cells with reduced c-secretase activity. PS deficiency enhanced nuclear translocation of ApoE and binding of ApoE to importin a4, a nuclear transport receptor. Moreover, the expression of PS mutants in PS-deficient cells suppressed the restoration effects on ApoE secretion compared with the expression of wild-type PS. Plasma ApoE levels were lower in FAD patients carrying PS1 mutations compared with normal control subjects. Our findings suggest a novel role of PS contributing to the pathogenesis of SAD by regulating ApoE secretion.
Alzheimer’s disease (AD) is characterized by neuronal loss and accumulation of amyloid β-protein (Aβ) in the brain parenchyma. Sleep impairment is associated with AD and affects about 25-40% of patients in the mild-to-moderate stages of the disease. Sleep deprivation leads to increased Aβ production; however, its mechanism remains largely unknown. We hypothesized that the increase in core body temperature induced by sleep deprivation may promote Aβ production. Here, we report temperature-dependent regulation of Aβ production. We found that an increase in temperature, from 37°C to 39°C, significantly increased Aβ production in amyloid precursor protein-overexpressing cells. We also found that high temperature (39°C) significantly increased the expression levels of heat shock protein 90 (Hsp90) and the C-terminal fragment of presenilin 1 (PS1-CTF), and promoted γ-secretase complex formation. Interestingly, Hsp90 was associated with the components of the premature γ-secretase complex, anterior pharynx defective-1 (APH-1) and nicastrin (NCT), but was not associated with PS1-CTF or presenilin enhancer-2. Hsp90 knockdown abolished the increased level of Aβ production and the increased formation of the γ-secretase complex at high temperature in culture. Furthermore, with in vivo experiments, we observed increases in the levels of Hsp90, PS1-CTF, NCT, and the γ-secretase complex in the cortex of mice housed at higher room temperature (30°C) compared with those housed at standard room temperature (23°C). Our results suggest that high temperature regulates Aβ production by modulating γ-secretase complex formation through the binding of Hsp90 to NCT/APH-1.
Using cross-section data in regression analysis, this paper examines the relationship between per capita real GDP and the human development index in high, medium and low human development countries. The sensitivity of the human development index to changes in per capita GDP is found to be highest in low human development countries. An 'inverted U' type relationship between per capita GDP and the human development index appears to be valid for medium human development countries.
A suitable plant regeneration system has been established using 3-4 weeks old calli derived from immature and mature seeds of four wheat varieties viz. Pavon 76, Akbar, Barkat, and Kanchan. As plant growth regulators, various auxins (2,4-D, BAP and IAA) either single or in combination were used in MS medium. The variety Pavon 76 showed maximum (72.25%) callus induction and Akbar exhibited the lowest (37.78%) from calli derived from immature seeds. Hormonal effects on callus induction were evaluated and significant results were found in case of genotypes at P <0.01. Out of four genotypes, the highest frequency of plant regeneration was recorded in Pavon 76 (67.00%) and lowest in Kanchan (43.10%) when 1.5 mg/l BAP and 0.5 mg/l IAA was added in the medium. It was observed that Pavon 76 produced highest number of green plants than others. For mature seeds all of the mentioned genotypes showed significant difference with maximum frequency of callusing in Pavon 76 (69.57%) in MS + 2.5 mg/l 2,4-D followed by Kanchan (60.84%), Barkat (52.73%), and Akbar (47.19%). For plant regeneration, Pavon 76 also showed best performance (64.36%) in MS + 2.0 BAP + 1.0 mg/l IAA, using calli derived from mature seeds. The other genotypes Barkat, Kanchan and Akbar exhibited 59.44, 52.71 and 52.32% regeneration in the same medium respectively. Here, the lowest regeneration (40.63%) was found in Akbar. In this case, it was aimed to establish a suitable protocol for in vitro callus induction and regeneration for advance biotechnological research on wheat in Bangladesh.
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