Experimental and quantum chemical calculations on corrosion inhibition of mild steel by two furan derivatives

Two furan derivatives namely 5-methylfurfurylamine (MFA) and furfurylamine (FAM) were investigated as corrosion inhibitors for mild steel in 1 M HCl. The corrosion inhibition efficiencies (IE) were measured at 0.005M of the inhibitors using electrochemical potentiodynamic polarization measurements. The studied furan derivatives inhibit mild steel corrosion in acidic medium. The MFA shows higher inhibition efficiency of 84.77% compared to FAM of 41.75%. Quantum chemical calculations were performed at the B3LYP/6-311++G(d,p) level of density functional theory (DFT). Several quantum parameters were calculated to study the correlation between the molecular structures and the corrosion inhibition performance of the inhibitors. The MFA inhibitor shows higher HOMO energy, softness (S), fraction of electrons transferred (ΔN), and lower energy gap (ΔE) compared to the FAM. This result indicates a better corrosion inhibition performance of the MFA inhibitor. The results show that the calculated values of the quantum parameters using DFT calculations are consistent with the experimental findings

The asymptotic iteration method for the angular spheroidal eigenvalues with arbitrary complex size parameter c

The asymptotic iteration method is applied, to calculate the angular spheroidal eigenvalues $\lambda^{m}_{\ell}(c)$ with arbitrary complex size parameter $c$. It is shown that, the obtained numerical results of $\lambda^{m}_{\ell}(c)$ are all in excellent agreement with the available published data over the full range of parameter values $\ell$, $m$, and $c$. Some representative values of $\lambda^{m}_{\ell}(c)$ for large real $c$ are also given.Comment: 15 pages, 1 figur

Genome-wide profiling of PARP1 reveals an interplay with gene regulatory regions and DNA methylation

Poly (ADP-ribose) polymerase-1 (PARP1) is a nuclear enzyme involved in DNA repair, chromatin remodeling and gene expression. PARP1 interactions with chromatin architectural multi-protein complexes (i.e. nucleosomes) alter chromatin structure resulting in changes in gene expression. Chromatin structure impacts gene regulatory processes including transcription, splicing, DNA repair, replication and recombination. It is important to delineate whether PARP1 randomly associates with nucleosomes or is present at specific nucleosome regions throughout the cell genome. We performed genome-wide association studies in breast cancer cell lines to address these questions. Our studies show that PARP1 associates with epigenetic regulatory elements genome-wide, such as active histone marks, CTCF and DNase hypersensitive sites. Additionally, the binding of PARP1 to chromatin genome-wide is mutually exclusive with DNA methylation pattern suggesting a functional interplay between PARP1 and DNA methylation. Indeed, inhibition of PARylation results in genome-wide changes in DNA methylation patterns. Our results suggest that PARP1 controls the fidelity of gene transcription and marks actively transcribed gene regions by selectively binding to transcriptionally active chromatin. These studies provide a platform for developing our understanding of PARP1's role in gene regulation

Indoor path loss model for 4G wireless network at 2.6 GHz

In this paper, a short-range, narrowband indoor propagation at 2.6 GHz was measured and modeled. The measurement campaign was conducted to characterize the path loss (PL) of Radio frequency (RF) at the Razak School building corridor. The corridor has unique structure and segmented in different sections. The irregular structure of corridor, further with various interior material used gives the unique characterization to the received power. The research work made in this paper is predominately targets to characterizing radio link of 2.6 GHz frequency in typical indoor corridor

Predictive model of 2-cyclohexylthiophene for corrosion inhibition in mild steel using computational method

Corrosion inhibition activity of 2-cyclohexylthiophene (2CHT) for mild steel in acidic media was predicted using QSAR tool. The model used two descriptors namely; Moran autocorrelation of lag4 weighted by mass (MATS4M) which explained the linearity and branching of the compounds and largest eigen values n3 of burden matrix weighted by mass (SPMAX3-Bh(m)) describes the nature and size of the neighboring atom. The modeling results revealed the potential of the compounds as a good corrosion inhibitor with percentage inhibition efficiency (%IE) of 76.5%. Quantum chemical calculation using DFT with 6-311G++(d,p) basis was used to evaluate the performance of the predicted compound as corrosion inhibitor by quantum chemical parameters such as EHUMO, ELUMO, Energy gap (Egap), hardness (?), softness (S), dipole moment (µ), electronegativity (X), electron affinity (A), ionization energy (I) and total energy (TE). The results obtained from quantum chemical parameters were found to be consistent with predicted result

Probing the Higgs Field Using Massive Particles as Sources and Detectors

In the Standard Model, all massive elementary particles acquire their masses by coupling to a background Higgs field with a non-zero vacuum expectation value. What is often overlooked is that each massive particle is also a source of the Higgs field. A given particle can in principle shift the mass of a neighboring particle. The mass shift effect goes beyond the usual perturbative Feynman diagram calculations which implicitly assume that the mass of each particle is rigidly fixed. Local mass shifts offer a unique handle on Higgs physics since they do not require the production of on-shell Higgs bosons. We provide theoretical estimates showing that the mass shift effect can be large and measurable, especially near pair threshold, at both the Tevatron and the LHC.Comment: 6 pages, no figures; Version 2 corrects some typographical errors of factors of 2 in equations 14, 17, 18 and 19 (all of the same origin) and mentions a linear collider as an interesting place to test the results of this pape

Tilted Circular Orbits around a Kerr Black Hole

We study circular orbits that are tilted with respect to the equatorial plane around a Kerr black hole. We write the equations for the parameters of a tilted circular orbit in terms of the orbit's radius and the Carter constant, or equivalently, the tilt angle. The tilted innermost stable circular orbits (TISCO)s are discussed as well as the last circular orbits. The azimuthal precession of an orbit is then studied and an approximate expression for the precession speed is given. We finally try to link tilted circular orbits to quai-periodic oscillations in some astrophysical black hole systems.Comment: This paper had been accepted for publication in PR

The Category 'D' Reconsidered

This study deals with the categorial status of a set of words known as 'determiners' and the features encoded in them. We argue, following a suggestion in Chomsky, 1975, that 'Optimality' conditions on grammar require grammatical categories to be 'primitive' in the sense that they must be unanalysable into further entities. The status of many words classified as determiners does not conform with this suggestion. The category 'D' is therefore a non-standard grammatical category. We have provided mathematical, morphological and syntactic arguments and facts drawn from a number of languages including Arabic, English, French, German, Hebrew, Italian, ...etc. showing that the category 'D' is not a 'primitive' category and therefore should be suspended and replaced by its 'primitive5 components. We have shown that 'genuine' determiners are morphologically complex where each element encodes a functional feature, such as 'person9, 'number9, 'gender9, 'proximate', 'definite', ...etc. These features, we claim, are functional categories. Many words classified as belonging to the category 'd' are in fact nouns or adjectives. Adopting an articulated theory of 'D' in which functional features are taken as functional categories is not only theoretically motivated but also has implications for language learn ability

Is the Royal London Space Analysis reliable and does it influence orthodontic treatment decisions?

The purpose of this study was to investigate the reliability of the Royal London Space Analysis (RLSA) and to evaluate its influence on orthodontic treatment decisions. Thirty-one case records were collected to represent various levels of crowding and different types of malocclusions. Seventeen examiners assessed these records and completed a data sheet that recorded information on their treatment decision. One month later, the examiners attended a course on the RLSA and then used the analysis to rescore the 31 cases. The models were also scored by the expert who led the course and these were then considered the 'gold standard' scores. After a further month, the examiners reapplied the RLSA and formulated a treatment plan for each set of patient records. A paired Student's t-test and intraclass correlation coefficient (ICC) were used to assess the agreement in scoring RLSA, a paired sample t-test was used to compare the scores with the gold standard, and finally the reliability in treatment planning was determined using kappa (κ) statistics.The scores for lower arch crowding showed the highest inter-examiner agreement with an ICC of 0.93 whereas the lowest level of agreement was for upper arch space requirement with an ICC of 0.77. Intra-examiner agreement was generally high, particularly for the assessment of lower arch crowding (ICC = 0.93) and lower arch space requirement (ICC = 0.88). There was excellent validity for all the examiners against the gold standard scores with a paired samples correlation ranging between 0.96 for lower arch crowding and 0.79 for upper arch space requirement. The intra-examiner reliability in treatment decision was only moderate, with an average κ value of 0.52 (maximum 0.82, minimum 0.24). Intra- and inter-examiner agreement for scoring the RLSA was acceptable. Nevertheless, the additional information obtained from the application of the RLSA did not have a substantial impact on the treatment decisions. © The Author 2008. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved