2,295 research outputs found
Thermodynamic properties of solid palladium-silver alloys and other alloys are investigated by torsion-effusion technique
Vapor pressure data obtained by the torsion-effusion method provides the thermodynamic properties of several transition-metal alloy systems. The vapor pressure of silver over solid silver and over palladium-silver alloys was measured and the results were more accurate than those found previously by other techniques
Monolithic Solid Oxide Fuel Cell development
The Monolithic Solid Oxide Fuel Cell (MSOFC) is an oxide-ceramic structure in which appropriate electronic and ionic conductors are fabricated in a honeycomb shape similar to a block of corrugated paperboard. These electronic and ionic conductors are arranged to provide short conduction paths to minimize resistive losses. The power density achievable with the MSOFC is expected to be about 8 kW/kg or 4 kW/L, at fuel efficienceis over 50 percent, because of small cell size and low resistive losses in the materials. The MSOFC operates in the range of 700 to 1000 C, at which temperatures rapid reform of hydrocarbon fuels is expected within the nickel-YSZ fuel channels. Tape casting and hot roll calendering are used to fabricate the MSOFC structure. The performance of the MSOFC has improved significantly during the course of development. The limitation of this system, based on materials resistance alone without interfacial resistances, is 0.093 ohm-sq cm area-specific resistance (ASR). The current typical performance of MSOFC single cells is characterized by ASRs of about 0.4 to 0.5 ohm-sq cm. With further development the ASR is expected to be reduced below 0.2 ohm-sq cm, which will result in power levels greater than 1.4 W/sq cm. The feasibility of the MSOFC concept was proven, and the performance was dramatically improved. The differences in thermal expansion coefficients and firing shrinkages among the fuel cell materials were minimized. As a result of good matching of these properties, the MSOFC structure was successfully fabricated with few defects, and the system shows excellent promise for development into a practical power source
INFLAMMATORY GENE EXPRESSION IN WOMEN DIAGNOSED WITH POLYCYSTIC OVARIAN SYNDROME
Polycystic ovarian syndrome (PCOS) is a common endocrine disorder in women of reproductive age. The pathophysiology of PCOS has conventionally thought to originate from androgen excess. However, recent evidence suggests that androgen excess is a downstream consequence to inflammatory dysregulation and subsequent metabolic abnormalities. Inflammatory mRNA gene expression of TNFa and IL-1ß in mononuclear cells isolated from women diagnosed with PCOS was explored using qPCR. Additionally, the correlations between body mass index (BMI) and fasting glucose on mRNA expression of TNFa and IL-1ß were explored. mRNA expression of both TNFa and IL-1ß were found to be significantly higher in PCOS subjects (P\u3c0.01). BMI was found to significantly increase mRNA expression of TNFa and IL-1ß (PP\u3c0.05)
Z-Selective Homodimerization of Terminal Olefins with a Ruthenium Metathesis Catalyst
The cross-metathesis of terminal olefins using a novel ruthenium catalyst results in excellent selectivity for the Z-olefin homodimer. The reaction was found to tolerate a large number of functional groups, solvents, and temperatures while maintaining excellent Z-selectivity, even at high reaction conversions
Z-Selectivity in Olefin Metathesis with Chelated Ru Catalysts: Computational Studies of Mechanism and Selectivity
The mechanism and origins of Z-selectivity in olefin metathesis with chelated Ru catalysts were explored using density functional theory. The olefin approaches from the “side” position of the chelated Ru catalysts, in contrast to reactions with previous unchelated Ru catalysts that favor the bottom-bound pathway. Steric repulsions between the substituents on the olefin and the N-substituent on the N-heterocyclic carbene ligand lead to highly selective formation of the Z product
Amphioxus SYCP1 : a case of retrogene replacement and co-option of regulatory elements adjacent to the ParaHox cluster
MGG was supported by the University of St Andrews School of Biology Biotechnology and Biological Sciences Research Council DTG and the Wellcome Trust ISSF. Work in the authors’ laboratory is also supported by the Leverhulme Trust.Retrogenes are formed when an mRNA is reverse transcribed and re-inserted into the genome in a location unrelated to the original locus. If this retrocopy inserts into a transcriptionally favourable locus and is able to carry out its original function, it can, in rare cases, lead to retrogene replacement. This involves the original, often multi-exonic, parental copy being lost whilst the newer single-exon retrogene copy ‘replaces’ the role of the ancestral parent gene. One example of this is amphioxus SYCP1, a gene that encodes a protein used in synaptonemal complex formation during meiosis, and which offers the opportunity to examine how a retrogene evolves after the retrogene replacement event. SYCP1 genes exist as large multi-exonic genes in most animals. AmphiSYCP1, however, contains a single coding exon of ~3200bp and has inserted next to the ParaHox cluster of amphioxus, whilst the multi-exonic ancestral parental copy has been lost. Here, we show that AmphiSYCP1 has not only replaced its parental copy, but has evolved additional regulatory function by co- opting a bidirectional promoter from the nearby AmphiCHIC gene. AmphiSYCP1 has also evolved a de novo, multi-exonic 5’untranslated region that displays distinct regulatory states, in the form of two different isoforms, and has evolved novel expression patterns during amphioxus embryogenesis in addition to its ancestral role in meiosis. Absence of ParaHox-like expression of AmphiSYCP1, despite its proximity to the ParaHox cluster, also suggests this gene is not influenced by any potential pan-cluster regulatory mechanisms, which are seemingly restricted to only the ParaHox genes themselves.Publisher PDFPeer reviewe
On the motion of hairy black holes in Einstein-Maxwell-dilaton theories
Starting from the static, spherically symmetric black hole solutions in
massless Einstein-Maxwell-dilaton (EMD) theories, we build a "skeleton" action,
that is, we phenomenologically replace black holes by an appropriate effective
point particle action, which is well suited to the formal treatment of the
many-body problem in EMD theories. We find that, depending crucially on the
value of their scalar cosmological environment, black holes can undergo steep
"scalarization" transitions, inducing large deviations to the general
relativistic two-body dynamics, as shown, for example, when computing the first
post-Keplerian Lagrangian of EMD theories
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MFN status and the choice of tariff regime
The gradualist approach to trade liberalization views the uniform tariffs implied by MFN status as an important step on the path to free trade. We investigate whether a regime of uniform tariffs will be preferable to discriminatory tariffs when countries engage in non-cooperative interaction in multilateral trade. The analysis includes product differentiation and asymmetric costs. We show that with the cost asymmetry the countries will disagree on the choice of tariff regime. When the choice of import tariffs and export subsidies is made sequentially the uniform tariff regime may not be sustainable, because of an incentive to deviate to a discriminatory regime. Hence, an international body is needed to ensure compliance with tariff agreement
Undergraduate Public Health Curriculum for UK Medical Schools: Consensus-statement 2014. Following a joint Public Health Educators in Medical Schools (PHEMS) / Faculty of Public Health (FPH) workshop on the undergraduate public health curriculum in medical schools, 2 April 2013, King’s College London, Guy’s Campus.
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