3,862 research outputs found
Exact O(g^2 alpha_s) top decay width from general massive two-loop integrals
We calculate the b-dependent self-energy of the top quark at O(g^2 \alpha_s)
by using a general massive two-loop algorithm proposed in a previous article.
From this we derive by unitarity the O(\alpha_s) radiative corrections to the
decay width of the top quark, where all effects associated with the quark
mass are included without resorting to a mass expansion. Our results agree with
the analytical results available for the O(\alpha_s) correction to the top
quark width
Submarine landslides in the Santa Barbara Channel as potential tsunami sources
International audienceRecent investigations using the Monterey Bay Aquarium Research Institutes (MBARI) Remotely Operated Vehicles (ROVs) "Ventana" and "Tiburon" and interpretation of MBARI's EM 300 30 kHz multibeam bathymetric data show that the northern flank of the Santa Barbara Basin has experienced massive slope failures. Of particular concern is the large (130 km2) Goleta landslide complex located off Coal Oil Point near the town of Goleta, that measures 14.6-km long extending from a depth of 90 m to nearly 574 m deep and is 10.5 km wide. We estimate that approximately 1.75 km3 has been displaced by this slide during the Holocene. This feature is a complex compound submarine landslide that contains both surfical slump blocks and mud flows in three distinct segments. Each segment is composed of a distinct head scarp, down-dropped head block and a slide debris lobe. The debris lobes exhibit hummocky topography in the central areas that appear to result from compression during down slope movement. The toes of the western and eastern lobes are well defined in the multibeam image, whereas the toe of the central lobe is less distinct. Continuous seismic reflection profiles show that many buried slide debris lobes exist and comparison of the deformed reflectors with ODP Drill Site 149, Hole 893 suggest that at least 200 000 years of failure have occurred in the area (Fisher et al., 2005a). Based on our interpretation of the multibeam bathymetry and seismic reflection profiles we modeled the potential tsunami that may have been produced from one of the three surfical lobes of the Goleta slide. This model shows that a 10 m high wave could have run ashore along the cliffs of the Goleta shoreline. Several other smaller (2 km2 and 4 km2) slides are located on the northern flank of the Santa Barbara Basin, both to the west and east of Goleta slide and on the Conception fan along the western flank of the basin. One slide, named the Gaviota slide, is 3.8 km2, 2.6 km long and 1.7 km wide. A distinct narrow scar extends from near the eastern head wall of this slide for over 2km eastward toward the Goleta slide and may represent either an incipient failure or a remnant of a previous failure. Push cores collected within the main head scar of this slide consisted of hydrogen sulfide bearing mud, possibly suggesting active fluid seepage and a vibra-core penetrated ~50 cm of recent sediment overlying colluvium or landslide debris confirming the age of ~300 years as proposed by Lee et al. (2004). However, no seeps or indications of recent movement were observed during our ROV investigation within this narrow head scar indicating that seafloor in the scar is draped with mud
The Effect of Repeated Electromagnetic Fields Stimulation in Biological Systems
The effects of electromagnetic fields on living organs have been explored with the use of both biological experimentation and computer simulations. In this paper we will examine the effects of the repeated electromagnetic field stimulation (REMFS) on cell cultures, mouse models, and computer simulations for diagnostic purposes. In our biological experiments we used 50 MHz and 64 MHz since this is approved in MRI systems. REMFS upregulated pathways that control the aging process such as proteostasis. REMFS delayed and reversed cellular senescence in mouse and human cell cultures. More recently we determined that REMFS decreases toxic protein beta amyloid levels, which is the cause of Alzheimer’s disease (AD), in human neuronal cultures. The mechanism of these effects is the reactivation of the heat shock factor 1 (HSF1). HSF1 activation is a quantum effect of the EMF-oscillations on the water that surrounds a long non-coding RNA, allowing it to then bind and activate the HSF1. We also performed electromagnetic (EM) computer simulations of virtual prototypes of bone cancer, femur fracture, and diabetic foot ulcers utilizing different frequencies and power applications to build an accurate differential diagnosis. These applications indicate the feasibility of subsequent practical models for diagnosing and treating human diseases
Realization of logically labeled effective pure states for bulk quantum computation
We report the first use of "logical labeling" to perform a quantum
computation with a room-temperature bulk system. This method entails the
selection of a subsystem which behaves as if it were at zero temperature -
except for a decrease in signal strength - conditioned upon the state of the
remaining system. No averaging over differently prepared molecules is required.
In order to test this concept, we execute a quantum search algorithm in a
subspace of two nuclear spins, labeled by a third spin, using solution nuclear
magnetic resonance (NMR), and employing a novel choice of reference frame to
uncouple nuclei.Comment: PRL 83, 3085 (1999). Small changes made to improve readability and
remove ambiguitie
Designing a miniaturised heated stage for in situ optical measurements of solid oxide fuel cell electrode surfaces, and probing the oxidation of solid oxide fuel cell anodes using in situ Raman spectroscopy
Methylation profiling and evaluation of demethylating therapy in renal cell carcinoma.
BACKGROUND: Despite therapeutic advances in targeted therapy, metastatic renal cell carcinoma (RCC) remains incurable for the vast majority of patients. Key molecular events in the pathogenesis of RCC include inactivation of the VHL tumour suppressor gene (TSG), inactivation of chromosome 3p TSGs implicated in chromatin modification and remodelling and de novo tumour-specific promoter methylation of renal TSGs. In the light of these observations it can be proposed that, as in some haematological malignancies, demethylating agents such as azacitidine might be beneficial for the treatment of advanced RCC. RESULTS: Here we report that the treatment of RCC cell lines with azacitidine suppressed cell proliferation in all 15 lines tested. A marked response to azacitidine therapy (>50% reduction in colony formation assay) was detected in the three cell lines with VHL promoter methylation but some RCC cell lines without VHL TSG methylation also demonstrated a similar response suggesting that multiple methylated TSGs might determine the response to demethylating therapies. To identify novel candidate methylated TSGs implicated in RCC we undertook a combined analysis of copy number and CpG methylation array data. Candidate novel epigenetically inactivated TSGs were further prioritised by expression analysis of RCC cell lines pre and post-azacitidine therapy and comparative expression analysis of tumour/normal pairs. Thus, with subsequent investigation two candidate genes were found to be methylated in more than 25% of our series and in the TCGA methylation dataset for 199 RCC samples: RGS7 (25.6% and 35.2% of tumours respectively) and NEFM in (25.6% and 30.2%). In addition three candidate genes were methylated in >10% of both datasets (TMEM74 (15.4% and 14.6%), GCM2 (41.0% and 14.6%) and AEBP1 (30.8% and 13.1%)). Methylation of GCM2 (P = 0.0324), NEFM (P = 0.0024) and RGS7 (P = 0.0067) was associated with prognosis. CONCLUSIONS: These findings provide preclinical evidence that treatment with demethylating agents such as azacitidine might be useful for the treatment of advanced RCC and further insights into the role of epigenetic changes in the pathogenesis of RCC
The effect of a lumbopelvic compression belt on load transfer during the active straight leg test: A proof of concept study using ultrasound imaging
INTRODUCTION: The active straight leg raise (ASLR) test assesses load transfer through the pelvis. During the ASLR, intraabdominal pressure (IAP) rises, increasing the load on the lumbopelvic region. Several studies have shown a correlation between the magnitude of bladder base displacement (BBD) during the ASLR and lumbopelvic instability. Additionally, greater depression of the bladder and pelvic floor muscles is associated with motor control impairments associated with form and force closure. Pelvic stability belts are a common therapeutic intervention for individuals who report pelvic girdle pain. Their mechanism of action is to improve form closure and assist force closure and motor control. Impaired form and force closure mechanisms through the lumbopelvic area are associated poor load transfer, low back pain, sacroiliac pain, stress urinary incontinence and chronic pelvic pain.
OBJECTIVES: This study aimed to observe and determine the impact of the ASLR test with and without a Serola lumbopelvic belt on BBD and participant self-reported level of difficulty score.
METHODS: A convenience sample of fifteen physical therapy students (mean age 25 years) who were previously identified as having lumbopelvic instability were recruited for this study. PCOM\u27s institutional review board approved the study, and each participant provided informed consent. All participants completed a bladder filling protocol via natural diuresis to standardize bladder volumes to allow for bladder and pelvic floor delineation on ultrasound imaging. A Clarius C3 curvilinear wireless ultrasound unit was used for image acquisition with images displayed on an IPAD. The ultrasound transducer was placed suprapublically on the lower abdomen, oriented transversely, and manipulated until a clear image of the bladder base was apparent. A standard script was read to each participant to standardize testing. The magnitude of BBD was captured with cine loops across two testing conditions: the ASLR test without a lumbopelvic belt which was repeated with the participant wearing a belt. Participants also self-reported the level of difficulty for each testing condition. Participants were fitted with the lumbopelvic belt according to manufacturer’s recommendation. The belt tension was standardized using a manometer set to 20mmHG placed between the belt\u27s anterior aspect and the participant\u27s lower abdomen. On-screen calipers identified the lateral and medial aspects of the bladder base. All images were saved for post hoc analysis to determine the magnitude and direction of BBD between both testing conditions.
RESULTS: Descriptive statistics will be reported, and a repeated measures ANOVA will be completed to determine whether there is a statistically significant difference between the means with the level of significance set at p=.05.
CONCLUSION: TB
Reduction of guide needle streak artifact in CT-guided biopsy
Purpose: Computed tomography (CT)–guided core needle biopsy (CNB) can be affected by streak artifact obscuring the needle tip. This study investigates factors that influence the occurrence and severity of streak artifact during CNB. Materials and Methods: Eight coaxial guide needles of two sizes from two manufacturers with and without stylets were imaged in a CT phantom, with CT reconstructed with adaptive statistical iterative reconstruction and filtered back projection. CNB-related streak artifact was quantified with profile analysis in an image-processing program. Differences between maximum attenuation at the needle tip and minimum attenuation in the streak artifact were compared for each variable. Diagnostic acceptability and streak artifact were subjectively assessed on each phantom image and on 40 clinical CNB procedures by three independent blinded reviewers following training case review. Results: Artifact was significantly less with the central stylet removed versus in situ (median, 1,145 HU vs 3,390 HU; P < .001) for all needles, and less for 19-gauge needles versus 17-gauge needles (median, 1,334 HU vs 2,780 HU, respectively; P = .006). There were no differences based on manufacturer (P = .906) or reconstruction algorithm (P = .524). Independent reviews found that streak artifact was significantly reduced when the central stylet was removed (κ = 0.875–1.0; P < .001), and needle tip position was better in cases in which the stylet was removed (κ = 0.231–0.711; P < .001). Conclusions: Streak artifact can be reduced and needle tip visualization improved by confirming final biopsy needle position with the central stylet removed on CT and using smaller-gauge guide needles
Highly effective liquid and solid phase extraction methods to concentrate radioiodine isotopes for radioiodination chemistry
Radioactive iodine isotopes play a pivotal role in radiopharmaceuticals. Large-scale production of multi-patient dose of radioiodinated nuclear medicines requires high concentration of radioiodine. We demonstrate that tetrabutylammonium chloride and methyltrioctylamonium chloride are effective phase transfer reagents to concentrate iodide-124, iodide-125 and iodide-131 from the corresponding commercial water solutions. The resulting concentrated radioiodide, in the presence of either phase transfer reagent, does not hamper the chemical reactivity of aqueous radioiodide in the copper (II)-mediated one-pot three-component click chemistry to produce radioiodinated iodotriazoles
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