991 resultados para Higgins, Sean


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A parallel kinematic machine (PKM) topology can only give its best performance when its geometrical parameters are optimized. In this paper, dimensional synthesis of a newly developed PKM is presented for the first time. An optimization method is developed with the objective to maximize both workspace volume and global dexterity of the PKM. Results show that the method can effectively identify design parameter changes under different weighted objectives. The PKM with optimized dimensions has a large workspace to footprint ratio and a large well-conditioned workspace, hence justifies its suitability for large volume machining.

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BackgroundRas-related nuclear protein (Ran) is required for cancer cell survival in vitro and human cancer progression, but the molecular mechanisms are largely unknown.MethodsWe investigated the effect of the v-myc myelocytomatosis viral oncogene homolog (Myc) on Ran expression by Western blot, chromatin immunoprecipitation, and luciferase reporter assays and the effects of Myc and Ran expression in cancer cells by soft-agar, cell adhesion, and invasion assays. The correlation between Myc and Ran and the association with patient survival were investigated in 14 independent patient cohorts (n = 2430) and analyzed with Spearman's rank correlation and Kaplan-Meier plots coupled with Wilcoxon-Gehan tests, respectively. All statistical tests were two-sided.ResultsMyc binds to the upstream sequence of Ran and transactivates Ran promoter activity. Overexpression of Myc upregulates Ran expression, whereas knockdown of Myc downregulates Ran expression. Myc or Ran overexpression in breast cancer cells is associated with cancer progression and metastasis. Knockdown of Ran reverses the effect induced by Myc overexpression in breast cancer cells. In clinical data, a positive association between Myc and Ran expression was revealed in 288 breast cancer and 102 lung cancer specimens. Moreover, Ran expression levels differentiate better or poorer survival in Myc overexpressing breast (?(2) = 24.1; relative risk [RR] = 9.1, 95% confidence interval [CI] = 3.3 to 24.7, P <.001) and lung (?(2) = 6.04; RR = 2.8, 95% CI = 1.2 to 6.3; P = .01) cancer cohorts.ConclusionsOur results suggest that Ran is required for and is a potential therapeutic target of Myc-driven cancer progression in both breast and lung cancers.

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Acute promyelocytic leukemia (APL) is associated with a reciprocal and balanced translocation involving the retinoic acid receptor-alpha (RARalpha). All-trans retinoic acid (ATRA) is used to treat APL and is a potent morphogen that regulates HOX gene expression in embryogenesis and organogenesis. HOX genes are also involved in hematopoiesis and leukemogenesis. Thirty-nine mammalian HOX genes have been identified and classified into 13 paralogous groups clustered on 4 chromosomes. They encode a complex network of transcription regulatory proteins whose precise targets remain poorly understood. The overall function of the network appears to be dictated by gene dosage. To investigate the mechanisms involved in HOX gene regulation in hematopoiesis and leukemogenesis by precise measurement of individual HOX genes, a small-array real-time HOX (SMART-HOX) quantitative polymerase chain reaction (PCR) platform was designed and validated. Application of SMART-HOX to 16 APL bone marrow samples revealed a global down-regulation of 26 HOX genes compared with normal controls. HOX gene expression was also altered during differentiation induced by ATRA in the PML-RARalpha(+) NB4 cell line. PML-RARalpha fusion proteins have been reported to act as part of a repressor complex during myeloid cell differentiation, and a model linking HOX gene expression to this PML-RARalpha repressor complex is now proposed.

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The purpose of this study was to examine the challenges of integrating an asthma disease management (DM) program into a primary care setting from the perspective of primary care practitioners. A second goal was to examine whether barriers differed between urban-based and nonurban-based practices. Using a qualitative design, data were gathered using focus groups in primary care pediatric practices. A purposeful sample included an equal number of urban and nonurban practices. Participants represented all levels in the practice setting. Important themes that emerged from the data were coded and categorized. A total of 151 individuals, including physicians, advanced practice clinicians, registered nurses, other medical staff, and nonmedical staff participated in 16 focus groups that included 8 urban and 8 nonurban practices. Content analyses identified 4 primary factors influencing the implementation of a DM program in a primary care setting. They were related to providers, the organization, patients, and characteristics of the DM program. This study illustrates the complexity of the primary care environment and the challenge of changing practice in these settings. The results of this study identified areas in a primary care setting that influence the adoption of a DM program. These findings can assist in identifying effective strategies to change clinical behavior in primary care practices. © 2008 Mary Ann Liebert, Inc.

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The multitude of biomolecular and regulatory factors involved in staphylococcal adhesion and biofilm formation owe much to their ability to colonize surfaces, allowing the biofilm form to become the preferential bacterial phenotype. Judging by total number, biomass and variety of environments colonized, bacteria can be categorized as the most successful lifeform on earth. This is due to the ability of bacteria and other microorganisms to respond phenotypically via biomolecular processes to the stresses of their surrounding environment. This review focuses on the specific pathways involved in the adhesion of the Gram-positive bacteria Staphylococcus epidermidis and Staphylococcus aureus with reference to the role of specific cell surface adhesins, the ica operon, accumulation-associated proteins and quorum-sensing systems and their significance in medical device-related infection.

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The characterization and understanding of body to body communication channels is a pivotal step in the development of emerging wireless applications such as ad-hoc personnel localisation and context aware body area networks (CABAN). The latter is a recent innovation where the inherent mobility of body area networks can be used to improve the coexistence of multiple co-located BAN users. Rather than simply accepting reductions in communication performance, sensed changes in inter-network co-channel interference levels may facilitate intelligent inter-networking; for example merging or splitting with other BANs that remain in the same domain. This paper investigates the inter-body interference using controlled measurements of the full mesh interconnectivity between two ambulatory BANs operating in the same environment at 2.45 GHz. Each of the twelve network nodes reported received signal strength to allow for the creation of carrier to interference ratio time series with an overall entire mesh sampling period of 54 ms. The results indicate that even with two mobile networks, it is possible to identify the onset of co-channel interference as the BAN users move towards each other and, similarly, the transition to more favourable physical layer channel conditions as they move apart. © 2011 IEEE.

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In recent years, the Infectious Diseases Society of America has highlighted a faction of antibiotic-resistant bacteria (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) - acronymically dubbed 'the ESKAPE pathogens' - capable of 'escaping' the biocidal action of antibiotics and mutually representing new paradigms in pathogenesis, transmission and resistance. This review aims to consolidate clinically relevant background information on the ESKAPE pathogens and provide a contemporary summary of bacterial resistance, alongside pertinent microbiological considerations necessary to face the mounting threat of antimicrobial resistance.

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OBJECTIVES: To evaluate the feasibility of an RCT of a pedometer-driven walking program and education/advice to remain active compared with education/advice only for treatment of chronic low back pain (CLBP). METHODS: Fifty-seven participants with CLBP recruited from primary care were randomly allocated to either: (1) education/advice (E, n=17) or (2) education/advice plus an 8-week pedometer-driven walking program (EWP, n=40). Step targets, actual daily step counts, and adverse events were recorded in a walking diary over the 8 weeks of intervention for the EWP group only. All other outcomes (eg, functional disability using the Oswestry Disability Questionnaire (ODQ), pain scores, physical activity (PA) measurement etc.) were recorded at baseline, week 9 (immediately post-intervention), and 6 months in both groups. RESULTS: The recruitment rate was 22% and the dropout rate was lower than anticipated (13% to 18% at 6 mo). Adherence with the EWP was high, 93% (n=37/40) walked for =6 weeks, and increased their steps/day [mean absolute increase in steps/d, 2776, 95% confidence interval (CI), 1996-3557] by 59% (95% CI, 40.73%-76.25%) from baseline. Mean percentage adherence with weekly step targets was 70% (95% CI, 62%-77%). Eight (20%) minor-related adverse events were observed in 13% (5/40) of the participants. The EWP group participants demonstrated an 8.2% point improvement [95% CI, -13 to -3.4] on the ODQ at 6 months compared with 1.6% points [95% CI, -9.3 to 6.1) for the E group (between group d=0.44). There was also a larger mean improvement in pain (d=0.4) and a larger increase in PA (d=0.59) at 6 months in EWP. DISCUSSION: This preliminary study demonstrated that a main RCT is feasible. EWP was safe and produced a real increase in walking; CLBP function and pain improved, and participants perceived a greater improvement in their PA levels. These improvements require confirmation in a fully powered RCT.

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TGF-ß1 is a prototypic profibrotic cytokine and major driver of fibrosis in the kidney and other organs. Induced in high glucose-1 (IHG-1) is a mitochondrial protein which we have recently reported to be associated with renal disease. IHG-1 amplifies responses to TGF-ß1 and regulates mitochondrial biogenesis by stabilising the transcriptional co-activator peroxisome proliferator-activated receptor gamma coactivator-1-alpha. Here we report that the mitochondrial localization of IHG-1 is pivotal in amplification of TGF-ß1 signaling. We demonstrate that IHG-1 expression is associated with repression of the endogenous TGF-ß1 inhibitor Smad7. Intriguingly, expression of a non-mitochondrial deletion mutant of IHG-1 (?mts-IHG-1) repressed TGF-ß1 fibrotic signaling in renal epithelial cells. In cells expressing ?mts-IHG-1 fibrotic responses including CCN2/connective tissue growth factor, fibronectin and jagged-1 expression were reduced following stimulation with TGF-ß1. ?mts-IHG-1 modulation of TGF-ß1 signaling was associated with increased Smad7 protein expression. ?mts-IHG-1 modulated TGF-ß1 activity by increasing Smad7 protein expression as it failed to inhibit TGF-ß1 transcriptional responses when endogenous Smad7 expression was knocked down. These data indicate that mitochondria modulate TGF-ß1 signal transduction and that IHG-1 is a key player in this modulation.

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Interest in bacteriophages as therapeutic agents has recently been reawakened. Parenteral delivery is the most routinely-employed method of administration. However, injection of phages has numerous disadvantages, such as the requirement of a health professional for administration and the possibility of cross-contamination. Transdermal delivery offers one potential means of overcoming many of these problems. The present study utilized a novel poly (carbonate) (PC) hollow microneedle (MN) device for the transdermal delivery of Escherichia coli-specific 14 bacteriophages both in vitro and in vivo. MN successfully achieved bacteriophage delivery in vitro across dermatomed and full thickness skin. A concentration of 2.67 x 10(6) PFU/ml (plaque forming units per ml) was detected in the receiver compartment when delivered across dermatomed skin and 4.0 x 10(3) PFU/ml was detected in the receiver compartment when delivered across full thickness skin. An in vivo study resulted in 4.13 x 10(3) PFU/ml being detected in blood 30 min following initial MN-mediated phage administration. Clearance occurred rapidly, with phages being completely cleared from the systemic circulation within 24 h, which was expected in the absence of infection. We have shown here that MN-mediated delivery allows successful systemic phage absorption. Accordingly, bacteriophage-based therapeutics may now have an alternative route for systemic delivery. Once fully-investigated, this could lead to more widespread investigation of these interesting therapeutic viruses. (c) 2012 Elsevier B.V. All rights reserved.

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Objective: To compare maternal and fetal leptin among women without diabetes, women with type 1 diabetes, and women with type 2 diabetes. 

Methods: In a prospective study at the National Maternity Hospital, Dublin, 40 women with type 1 diabetes, 10 with type 2 diabetes, and 30 without diabetes were enrolled between July 2006 and July 2008. Maternal (36-week) and cord blood leptin was measured by enzyme-linked immunoassay. 

Results: No difference was found in maternal leptin among the groups: without diabetes (mean, range): 325 pg/mL, 36-1492 pg/mL; type 1 diabetes: 343.2 pg/mL, 55.5-1108.2 pg/mL; type 2 diabetes: 2022 pg/mL, 35.1-1553.3 pg/mL (P>0.05). Leptin levels were higher among fetuses of women with type 1 (223 pg/mL, 25.7-810 pg/mL) and type 2 (447.2 pg/mL, 1363-679 pg/mL) diabetes than among women without diabetes (803 pg/mL, 273-623.1 pg/mL; P<0.05). The single significant predictor of fetal leptin for the whole cohort was maternal body mass index (BMI; r=039, P=0.01). Only third-trimester glycosylated hemoglobin (HbA1c) was significantly related to fetal leptin after controlling for maternal BMI among women with diabetes (r=028, P=0.04).

 Conclusion: Fetuses of women with diabetes might have some degree of leptin resistance. This might be important in appetite regulation in extrauterine life. (C) 2012 International Federation of Gynecology and Obstetrics. 

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The economic, cultural and political development of Belfast