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Search Results: 1 - 10 of 26594 matches for " Paul Davis "
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A Killing tensor for higher dimensional Kerr-AdS black holes with NUT charge
Paul Davis
Mathematics , 2006, DOI: 10.1088/0264-9381/23/10/023
Abstract: In this paper, we study the recently discovered family of higher dimensional Kerr-AdS black holes with an extra NUT-like parameter. We show that the inverse metric is additively separable after multiplication by a simple function. This allows us to separate the Hamilton-Jacobi equation, showing that geodesic motion is integrable on this background. The separation of the Hamilton-Jacobi equation is intimately linked to the existence of an irreducible Killing tensor, which provides an extra constant of motion. We also demonstrate that the Klein-Gordon equation for this background is separable.
Separability of multi-charge black holes in supergravity
Paul Davis
Mathematics , 2006, DOI: 10.1088/0264-9381/23/23/014
Abstract: In this paper, we show that some five-dimensional rotating black hole solutions of both gauged and ungauged supergravity, with independent rotation parameters and three charges admit separable solutions to the massless Hamilton-Jacobi and Klein-Gordon equations. This allows us to write down a conformal Killing tensor for the spacetime. Conformal Killing tensors obey an equation involving a co-vector field. We find this co-vector field in three specific examples, and also give a general formula for it.
Toxoplasma on the Brain: Understanding Host-Pathogen Interactions in Chronic CNS Infection
Sushrut Kamerkar,Paul H. Davis
Journal of Parasitology Research , 2012, DOI: 10.1155/2012/589295
Abstract: Toxoplasma gondii is a prevalent obligate intracellular parasite which chronically infects more than a third of the world’s population. Key to parasite prevalence is its ability to form chronic and nonimmunogenic bradyzoite cysts, which typically form in the brain and muscle cells of infected mammals, including humans. While acute clinical infection typically involves neurological and/or ocular damage, chronic infection has been more recently linked to behavioral changes. Establishment and maintenance of chronic infection involves a balance between the host immunity and parasite evasion of the immune response. Here, we outline the known cellular interplay between Toxoplasma gondii and cells of the central nervous system and review the reported effects of Toxoplasma gondii on behavior and neurological disease. Finally, we review new technologies which will allow us to more fully understand host-pathogen interactions. 1. Introduction Toxoplasma gondii belongs to the phylum Apicomplexa, which consists of intracellular parasites having a characteristically polarized cell structure and a complex cytoskeletal and organellar arrangement at their apical end [1]. This obligate intracellular parasite can infect and replicate within virtually any nucleated mammalian or avian cell [2, 3]. It is believed that the major transmission method of T. gondii to humans is the consumption of raw or rare meat [4–6]. In addition, vertical transmission of T. gondii is also possible, occurring when a female receives a primary infection while pregnant which can lead to fetal morbidity such as hydrocephaly. Indeed, T. gondii infection is a primary cause of fetal malformations in the United States [7]. Up to 80% of a population may be infected, depending on eating habits and exposure to felines, which serve as the definitive hosts and shed environmentally robust oocysts in feces [7, 8]. Oocysts can be stable in the environment for up to a year, may contaminate food or water supplies, and infect other warm blooded vertebrates [9]. A recent study suggested that oocyst-acquired infections are the most clinically severe form of infection, which may occur not just through direct cat fecal exposure, but contamination of municipal drinking water [10]. Two critical intracellular stages in the pathogenesis and transmission of Toxoplasma gondii are the rapidly replicating tachyzoite stage and the slower growing, cyst-forming bradyzoite stage. Initially, latent infections in humans were assumed to be largely asymptomatic. However, during the initial AIDS crisis, Toxoplasma became known as a
Social function in schizophrenia and schizoaffective disorder: Associations with personality, symptoms and neurocognition
Paul H Lysaker, Louanne W Davis
Health and Quality of Life Outcomes , 2004, DOI: 10.1186/1477-7525-2-15
Abstract: A self-report measure of the five factor model of personality was gathered along with ratings of social function, symptoms and assessments of neurocognition for 65 participants with schizophrenia or schizoaffective disorder.Univariate correlations and stepwise multiple regression indicated that frequency of social interaction was predicted by higher levels of the trait of Agreeableness, fewer negative symptoms, better verbal memory and at the trend level, lesser Neuroticism (R2 = .42, p < .0001). In contrast, capacity for intimacy was predicted by fewer negative symptoms, higher levels of Agreeableness, Openness, and Conscientiousness and at the trend level, fewer positive symptoms (R2 = .67, p < .0001).Taken together, the findings of this study suggest that person-centered variables such as personality, may account for some of the broad differences seen in outcome in schizophrenia spectrum disorders, including social outcomes. One interpretation of the results of this study is that differences in personality combine with symptoms and neurocognitive deficits to affect how persons with schizophrenia are able to form and sustain social connections with others.Interest has increasingly grown in understanding how differences in personality may affect outcome in schizophrenia [1,2]. Just as in a wide range of other severe and debilitating medical conditions [3-7], the manner in which people interpret and respond to a life touched by schizophrenia may deeply impact upon the recovery process [8-11].To date, one model of personality that has shown some promise in helping to systematically document the types of individual differences that help or hinder outcome in schizophrenia, is the "Five factor" model [12]. This model posits five endogenous traits [13] along which all persons vary, regardless of their socioeconomic status or culture and which exert an enduring impact on behavior, affect and cognition across the lifespan [14]. These five dimensions are Neuroticism, or vul
Group B streptococcus tricuspid endocarditis presenting with arthralgia in a postpartum woman: a case report
Vincent Paul,Davis Russell,Roy Debashis
Journal of Medical Case Reports , 2012, DOI: 10.1186/1752-1947-6-242
Abstract: Introduction Infective endocarditis presenting with arthralgia is rare. Group B streptococcus tricuspid endocarditis as a postpartum complication is even rarer. The present case is an example of both. Case presentation We report the case of a 30-year-old Caucasian woman who presented with painful swelling of her wrists and ankles. Conclusion Even when the clinical presentation of systemic inflammation is more suggestive of a primary rheumatological disorder, it is important to remember that bacterial infection can also present in this manner. Group B streptococcus tricuspid valve endocarditis is a rare, but recognized, postpartum complication.
Unique MR Findings in a Case Series of Two Symptomatic Patients with Peliosis Hepatis  [PDF]
Drew Pierce, Christopher S. Davis, Paul M. Bloomston, Zarine K. Shah
Open Journal of Radiology (OJRad) , 2014, DOI: 10.4236/ojrad.2014.41010

Purpose: The aim of this report is to describe the unusual MR imaging characteristics observed in two patients with biopsy-proven peliosis hepatis. Imaging findings using gadoxetate disodium (Eovist) as the contrast agent in a patient with peliosis hepatis are presented for the first time. Methods: This is a retrospective review of the MRI findings in two patients reviewed independently by two specialized abdominal imaging radiologists. The radiological findings were correlated with clinical history and histopathology. Results: Peliosis hepatis is a rare clinical and radiological entity that is often a diagnostic dilemma due to its non-specific clinical characteristics. Unusual imaging characteristics in this rare entity make diagnosis even more challenging. Conclusions: Improved understanding of the imaging characteristics of peliosis hepatis may prevent unnecessary and potentially dangerous biopsies in select patients with peliosis hepatis. This requires a high index of suspicion for practicing radiologists due to the rarity of this disease.

Special symmetries of the charged Kerr-AdS black hole of D=5 minimal gauged supergravity
Paul Davis,Hari K. Kunduri,James Lucietti
Physics , 2005, DOI: 10.1016/j.physletb.2005.09.062
Abstract: In this note we prove that the Hamilton-Jacobi equation in the background of the recently discovered charged Kerr-AdS black hole of D=5 minimal gauged supergravity is separable, for arbitrary values of the two rotation parameters. This allows us to write down an irreducible Killing tensor for the spacetime. As a result we also show that the Klein-Gordon equation in this background is separable. We also consider the Dirac equation in this background in the special case of equal rotation parameters and show it has separable solutions. Finally we discuss the near-horizon geometry of the supersymmetric limit of the black hole.
The Interaction of N-Acylhomoserine Lactone Quorum Sensing Signaling Molecules with Biological Membranes: Implications for Inter-Kingdom Signaling
Benjamin Michael Davis,Rasmus Jensen,Paul Williams,Paul O'Shea
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0013522
Abstract: The long chain N-acylhomoserine lactone (AHL) quorum sensing signal molecules released by Pseudomonas aeruginosa have long been known to elicit immunomodulatory effects through a process termed inter-kingdom signaling. However, to date very little is known regarding the exact mechanism of action of these compounds on their eukaryotic targets.
Combined QM/MM Study of Thyroid and Steroid Hormone Analogue Interactions with Integrin
Marek Freindorf,Thomas R. Furlani,Jing Kong,Vivian Cody,Faith B. Davis,Paul J. Davis
Journal of Biomedicine and Biotechnology , 2012, DOI: 10.1155/2012/959057
Abstract: Recent biochemical studies have identified a cell surface receptor for thyroid and steroid hormones that bind near the arginine-glycine-aspartate (RGD) recognition site on the heterodimeric αvβ3 integrin. To further characterize the intermolecular interactions for a series of hormone analogues, combined quantum mechanical and molecular mechanical (QM/MM) methods were used to calculate their interaction energies. All calculations were performed in the presence of either calcium (Ca2
The Relationship between Hypomagnesemia, Metformin Therapy and Cardiovascular Disease Complicating Type 2 Diabetes: The Fremantle Diabetes Study
Kirsten E. Peters, S. A. Paul Chubb, Wendy A. Davis, Timothy M. E. Davis
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0074355
Abstract: Background Low serum magnesium concentrations have been associated with cardiovascular disease risk and outcomes in some general population studies but there are no equivalent studies in diabetes. Metformin may have cardiovascular benefits beyond blood glucose lowering in type 2 diabetes but its association with hypomagnesemia appears paradoxical. The aim of this study was to examine relationships between metformin therapy, magnesium homoeostasis and cardiovascular disease in well-characterized type 2 patients from the community. Methods and Findings We studied 940 non-insulin-treated patients (mean±SD age 63.4±11.6 years, 49.0% males) from the longitudinal observational Fremantle Diabetes Study Phase I (FDS1) who were followed for 12.3±5.3 years. Baseline serum magnesium was measured using stored sera. Multivariate methods were used to determine associates of prevalent and incident coronary heart disease (CHD) and cerebrovascular disease (CVD) as ascertained from self-report and linked morbidity/mortality databases. 19% of patients were hypomagnesemic (serum magnesium <0.70 mmol/L). Patients on metformin, alone or combined with a sulfonylurea, had lower serum magnesium concentrations than those on diet alone (P<0.05). There were no independent associations between serum magnesium or metformin therapy and either CHD or CVD at baseline. Incident CVD, but not CHD, was independently and inversely associated with serum magnesium (hazard ratio (95% CI) 0.28 (0.11–0.74); P = 0.010), but metformin therapy was not a significant variable in these models. Conclusions Since hypomagnesemia appears to be an independent risk factor for CVD complicating type 2 diabetes, the value of replacement therapy should be investigated further, especially in patients at high CVD risk.
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