Staphylococcus aureus typing by digestion of protein A coding gene using Bsp143I

Background: Protein A is the virulence factors of Staphylococcus aureus rolling in its pathogenesis, and its gene is used for typing. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with different enzymes has been used for this action. Objectives: In this study, we used Bsp143I enzyme for digestion of the gene, coding protein A (spa gene) in S. aureus. The bacteria were isolated from patients and healthy carriers in Gorgan, north of Iran. Patients and Methods: DNAs of 128 S. aureus subjects (53 from healthy carriers and 75 from patients) were extracted and amplified using specific primers of the spa gene. The product was digested by Bsp143I enzyme and its pattern was assessed by gel electrophoresis. Results: There were seven spa types among the tested S. aureus samples, among which six types differed in the repeated X region of the spa gene, but the seventh type had a deletion on one of BSP143I restriction sites. The frequency of spa types among isolated S. aureus samples as well as healthy carriers was six and five, respectively. S. aureus isolated from wounds showed the most diverse spa types (five) among clinical samples. Types 1, 2 and 4 were observed in all clinical samples, while only one case of type 3 was identified among patients, whereas this type constituted over 32% of the isolates among carriers. We found seven and four spa types among methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) isolates, respectively. Conclusions: Our results showed that typing the spa gene using PCR-RFLP using Bsp143I was an acceptable method for typing S. aureus. Furthermore, this survey showed that the types in healthy carriers and MSSA were more variable than patient and MRSA isolates, respectively. We used the Bsp143I enzyme, which was not used in any previous studies on the spa gene. The results of this study suggested that we can use PCR-RFLP of spa gene by Bsp143I for molecular typing and sequencing of S. aureus, instead of relatively expensive methods. This method is relatively rapid and inexpensive, and can be accomplished in centers with conventional molecular facilities. © 2014, Ahvaz Jundishapur University of Medical Sciences

Ultrasonic characterisation of wheel hub/axle interference fit pressures

Railway wheels are secured onto the axle by means of an interference fit. The wheel is press fitted onto a pre-lubricated axle, and the resulting interference fit induces a contact pressure at the interface. Occasionally railway wheels fail by fatigue, with the initiation point for the failure frequently traced to the interference fit. The aim of this work is to use ultrasonic reflection to non-destructively determine contact conditions in the interference fit. The rough surface contact at the interference fit interface behaves like a spring. If the contact pressure is high the interface is conformal with few air gaps, the stiffness is then high and the transmission of an ultrasonic wave is permitted. However, when pressure is low more air gaps exist, interfacial stiffness is then reduced and more of the ultrasound is reflected. Normalised contact pressure was determined from this stiffness. Maps of the interface have been produced which show the contact pressure to peak at the edges of the fit, and to experience a continuous variation about a mean value elsewhere

Transport and reduction of nitrate in clayey till underneath forest and arable land.

Transport and reduction of nitrate in a typically macroporous clayey till were examined at variable flow rate and nitrate flux. The experiments were carried out using saturated, large diameter (0.5 m), undisturbed soil columns (LUC), from a forest and nearby agricultural sites. Transport of nitrate was controlled by flow along the macropores (fractures and biopores) in the columns. Nitrate reduction (denitrification) determined under active flow mainly followed first order reactions with half-lives (t1/2) increasing with depth (1.5–3.5 m) from 7 to 35 days at the forest site and 1–7 h at the agricultural site. Nitrate reduction was likely due to microbial degradation of accumulated organic matter coupled with successive consumption of O2 and NO3− in the macropore water followed by reductive dissolution of Fe and Mn from minerals along the macropores. Concentrations of total organic carbon measured in soil samples were near identical at the two study sites and consequently not useful as indicator for the observed differences in nitrate reduction. Instead the high reduction rates at the agricultural site were positively correlated with elevated concentration of water-soluble organic carbon and nitrate-removing bacteria relative to the forest site. After high concentrations of water-soluble organic carbon in the columns from the agricultural site were leached they lost their elevated reduction rates, which, however, was successfully re-established by infiltration of new reactive organics represented by pesticides. Simulations using a calibrated discrete fracture matrix diffusion (DFMD) model could reasonably reproduce the denitrification and resulting flux of nitrate observed during variable flow rate from the columns

Human chondrocyte culture models for studying cyclooxygenase expression and prostaglandin regulation of collagen gene expression

AbstractObjectiveSince articular chondrocytes and synovial fibroblasts are particularly responsive to interleukin-1 (IL-1) with respect to stimulation of prostaglandin E2(PGE2) biosynthesis, we have used them as models to examine feedback modulatory effects of PGE2, which blocks or attenuates the direct effects of IL-1β on cell-specific collagen gene expression.MethodsImmortalized human chondrocytes were developed for studying responses to cytokines and prostaglandins. Regulatory sequences of the type II collagen gene (COL2A1) in reporter gene constructs were analyzed in transient transfection experiments. Endogenous expression of COL2A1 mRNA, as well as aggrecan, biglycan, and decorin mRNAs, and IL-1-inducible cyclooxygenase (COX-2), phospholipase A2 (PLA2), and inducible nitric oxide synthetase (iNOS) mRNAs were analyzed by RT-PCR.ResultsPrevious work has shown that IL-1β inhibits, while prostaglandins stimulate COL2A1 expression. In different immortalized chondrocyte cell lines, the ability to respond to IL-1β with increased levels of COX-2, PLA2, and iNOS mRNAs depends upon expression of the differentiated chrondrocyte phenotype.ConclusionsOur studies suggest that some IL-1-induced responses in chondrocytes may require differentiation-specific transcription factors that could serve as therapeutic targets for arthritis

Recursion Relations for One-Loop Gravity Amplitudes

We study the application of recursion relations to the calculation of finite one-loop gravity amplitudes. It is shown explicitly that the known four, five, and six graviton one-loop amplitudes for which the external legs have identical outgoing helicities, and the four graviton amplitude with helicities (-,+,+,+) can be derived from simple recursion relations. The latter amplitude is derived by introducing a one-loop three-point vertex of gravitons of positive helicity, which is the counterpart in gravity of the one-loop three-plus vertex in Yang-Mills. We show that new issues arise for the five point amplitude with helicities (-,+,+,+,+), where the application of known methods does not appear to work, and we discuss possible resolutions.Comment: 28 pages, LaTeX, 12 figures. v2:typos and references correcte

The Limits of Intention in the Common Law

In criminal law, intention functions as the concept whereby human actions, and the reasons for them, are understood in relation to a criminal system. If there is no law, then there can be no punishment; but what if there is law, what then? How are the actions of the accused supposed to be understood in relation to the criminal law? One is very much aware that the criminal law, as it is presently conducted, generally pits the smallness of an individual against the corporate greatness and might of the state. What ought to serve to balance these competing interests? In any philosophical exploration one attempts to return to the source of the issue under scrutiny. In this exploration of intention the sources have been wide and varied and, at times, rare and difficult to obtain. There seem to be no clear and precise links from one moment of legal history to another. One is required to make educated guesses, thoughtful assumptions, and proffer what seem to be reasonable links from one epoch into the next. One reading of the sources suggests that intention is a volitive concept. Its beginnings as malice aforethought suggest that the accused had been moved to break the law (a law which was believed to have a moral foundation) because of his own disruption of character and moral disquietude. One did the deed, not thought the deed. However, the violation of a law which had a moral foundation leads one to ask further questions about both law and morals. Law and morals have distinct spheres. Is it possible that there is a common link between the ability to break a social law, and the ability to break a moral law? From history one will remember how both Bracton and Fleta admitted how both spheres could surround a human act. At times the spheres overlap, and at other times they are separate. Common, however, to each sphere is the ability and capacity of mankind to move within those spheres. This leads into the old and common effort to inquire into the nature of mankind. Without doubt, it is true that mankind possesses a nature. Whether that nature can be deciphered, decoded, and put into well defined, nonambiguous sets of linguistic propositions has been and is the rub. Historic modes of thought about human nature identified two broad differences: intellect and will. For centuries these broad conceptual differences seemed to take on concrete forms of their own. One\u27s will and intellect seemed to be reified in moral and theological writings, as if each were possessed of its own distinct identity, acting for its own distinct ends. Added to this reification of will and intellect, one further distinction was set forth that something about man\u27s nature put him into both a world of matter (mass and extension) and of spirit (energy and infinitude). Could any more contradictory sets of postulates have been integrated into a growing legal system

Covariant Quantization of Superstrings Without Pure Spinor Constraints

We construct a covariant quantum superstring, extending Berkovits' approach by introducing new ghosts to relax the pure spinor constraints. The central charge of the underlying Kac-Moody algebra, which would lead to an anomaly in the BRST charge, is treated as a new generator with a new b-c system. We construct a nilpotent BRST current, an anomalous ghost current and an anomaly-free energy-momentum tensor. For open superstrings, we find the correct massless spectrum. In addition, we construct a Lorentz invariant B-field to be used for the computation of the integrated vertex operators and amplitudes.Comment: 30 page

Type II and heterotic one loop string effective actions in four dimensions

We analyze the reduction to four dimensions of the R^4 terms which are part of the ten-dimensional string effective actions, both at tree level and one loop. We show that there are two independent combinations of R^4 present, at one loop, in the type IIA four dimensional effective action, which means they both have their origin in M-theory. The d=4 heterotic effective action also has such terms. This contradicts the common belief thathere is only one R^4 term in four-dimensional supergravity theories, given by the square of the Bel-Robinson tensor. In pure N=1 supergravity this new R^4 combination cannot be directly supersymmetrized, but we show that, when coupled to a scalar chiral multiplet (violating the U(1) $R$-symmetry), it emerges in the action after elimination of the auxiliary fields.Comment: v2: 22 pages. Discussion on the new R^4 term and extended supergravity has been abridged and improved. Published versio

Diffusion Limited Aggregation with Power-Law Pinning

Using stochastic conformal mapping techniques we study the patterns emerging from Laplacian growth with a power-law decaying threshold for growth $R_N^{-\gamma}$ (where $R_N$ is the radius of the $N-$ particle cluster). For $\gamma > 1$ the growth pattern is in the same universality class as diffusion limited aggregation (DLA) growth, while for $\gamma < 1$ the resulting patterns have a lower fractal dimension $D(\gamma)$ than a DLA cluster due to the enhancement of growth at the hot tips of the developing pattern. Our results indicate that a pinning transition occurs at $\gamma = 1/2$, significantly smaller than might be expected from the lower bound $\alpha_{min} \simeq 0.67$ of multifractal spectrum of DLA. This limiting case shows that the most singular tips in the pruned cluster now correspond to those expected for a purely one-dimensional line. Using multifractal analysis, analytic expressions are established for $D(\gamma)$ both close to the breakdown of DLA universality class, i.e., $\gamma \lesssim 1$, and close to the pinning transition, i.e., $\gamma \gtrsim 1/2$.Comment: 5 pages, e figures, submitted to Phys. Rev.