180 research outputs found
New Target Genes for the Peroxisome Proliferator-Activated Receptor-Ī³ (PPARĪ³) Antitumour Activity: Perspectives from the Insulin Receptor
The insulin receptor (IR) plays a crucial role in mediating the metabolic and proliferative functions triggered by the peptide hormone insulin. There is considerable evidence that abnormalities in both IR expression and function may account for malignant transformation and tumour progression in some human neoplasias, including breast cancer. PPARĪ³ is a ligand-activated, nuclear hormone receptor implicated in many pleiotropic biological functions related to cell survival and proliferation. In the last decade, PPARĪ³ agonistsābesides their known action and clinical use as insulin sensitizersāhave proved to display a wide range of antineoplastic effects in cells and tissues expressing PPARĪ³, leading to intensive preclinical research in oncology. PPARĪ³ and activators affect tumours by different mechanisms, involving cell proliferation and differentiation, apoptosis, antiinflammatory, and antiangiogenic effects. We recently provided evidence that PPARĪ³ and agonists inhibit IR by non canonical, DNA-independent mechanisms affecting IR gene transcription. We conclude that IR may be considered a new PPARĪ³ ātargetā gene, supporting a potential use of PPARĪ³ agonists as antiproliferative agents in selected neoplastic tissues that overexpress the IR
A Proposed Grading System to Standardize the Description of Renal Papillary Appearance at the Time of Endoscopy in Patients with Nephrolithiasis
BACKGROUND AND PURPOSE:
The appearance of the renal papillae in patients with nephrolithiasis can be quite variable and can range from entirely healthy to markedly diseased. The implications of such findings remain unknown. One potential reason is the lack of a standardized system to describe such features. We propose a novel grading scale to describe papillary appearance at the time of renal endoscopy.
METHODS:
Comprehensive endoscopic renal assessment and mapping were performed on more than 300 patients with nephrolithiasis. Recurring abnormal papillary characteristics were identified and quantified based on degree of severity.
RESULTS:
Four unique papillary features were chosen for inclusion in the PPLA scoring system- ductal Plugging, Pitting, Loss of contour, and Amount of Randall's plaque. Unique scores are calculated for individual papillae based on reference examples.
CONCLUSIONS:
The description and study of renal papillary appearance in stone formers have considerable potential as both a clinical and research tool; however, a standardized grading system is necessary before using it for these purpos
A prototype model for evaluating SKA-LOW station calibration
The Square Kilometre Array telescope at low-frequency (SKA-Low) will be a phased array telescope supporting a wide
range of science cases covering the frequency band 50 - 350 MHz, while at the same time asking for high sensitivity and
excellent characteristics. These extremely challenging requirements resulted in a design using 512 groups of 256 log
periodic dual polarized antennas each (where each group is called āstationā), for a total of 131072 antennas. The 512
stations are randomly distributed mostly within a dense area around the centre of the SKA-Low, and then in 3 arms having
16 station clusters each.
In preparation for the SKA Phase 1 (SKA1) System Critical Design Review (CDR), prototype stations were deployed at
the Murchison Radio-astronomy Observatory (MRO) site (Western Australia) near the Murchison Widefield Array
(MWA) radio telescope. The project involved multiple parties in an International collaboration building and testing
different prototypes of the SKA1-Low station near the actual site. This resulted in both organisational and logistic
challenges typical of a deployment of the actual telescope.
The test set-up involved a phased build-up of the complex station of log-periodic antennas, by starting from the deployment
of 48 antennas and related station signal processing (called AAVS1.5, where AAVS stands for Aperture Array Verification
System), followed by expansion to a full station (AAVS2.0). As reference a station with dipole antennas EDA2 (EDA:
Engineering Development Array) was deployed. This test set-up was used for an extensive test and evaluation programme.
All test antenna configurations were simulated in detail by electromagnetic (EM) models, and the prediction of the models
was further verified by appropriate tests with a drone-based radio frequency source. Astronomical observations on Sun
and galaxy transit were performed with calibrated stations of both EDA2, AAVS1.5 and AAVS2.0. All 3 configurations
were calibrated. EM modelling and calibration results for the full station AAVS2.0 and EM verification for the AAVS1.5
station are presented.
The comparisons between the behaviour of the log-periodic antennas and the dipoles have advanced our understanding the
calibration quality and the technological maturity of the future SKA1-Low array
Nephrocalcinosis in Calcium Stone Formers Who Do Not Have Systemic Disease
Purpose
Nephrocalcinosis is commonly present in primary hyperparathyroidism, distal renal tubular acidosis and medullary sponge kidney disease. To our knowledge it has not been studied in patients with calcium phosphate stones who do not have systemic disease.
Materials and Methods
We studied patients undergoing percutaneous nephrolithotomy who had calcium phosphate or calcium oxalate stones and did not have hyperparathyroidism, distal renal tubular acidosis or medullary sponge kidney disease. On postoperative day 1 all patients underwent noncontrast computerized tomography. If there were no residual calcifications, the patient was categorized as not having nephrocalcinosis. If there were residual calcifications, the patient underwent secondary percutaneous nephrolithotomy. If the calcifications were found to be stones, the patient was categorized as not having nephrocalcinosis. If the calcifications were not stones, the patient was categorized as having nephrocalcinosis. Patients were grouped based on the type of stones that formed, including hydroxyapatite, brushite and idiopathic calcium oxalate. The extent of nephrocalcinosis was quantified as 0āabsent nephrocalcinosis to 3āextensive nephrocalcinosis. Patients with residual calcifications on postoperative day 1 noncontrast computerized tomography who did not undergo secondary percutaneous nephrolithotomy were excluded from analysis. The presence or absence of nephrocalcinosis was correlated with metabolic studies.
Results
A total of 67 patients were studied, including 14 with hydroxyapatite, 19 with brushite and 34 with idiopathic calcium oxalate calculi. Nephrocalcinosis was present in 10 of 14 (71.4%), 11 of 19 (57.9%) and 6 of 34 patients (17.6%) in the hydroxyapatite, brushite and idiopathic calcium oxalate groups, respectively (chi-square p = 0.01). The mean extent of nephrocalcinosis per group was 1.98, 1.32 and 0.18 for hydroxyapatite, brushite and idiopathic calcium oxalate, respectively (p ā¤0.001). The presence of nephrocalcinosis positively correlated with urine calcium excretion (mean Ā± SD 287.39 Ā± 112.49 vs 223.68 Ā± 100.67 mg per day, p = 0.03).
Conclusions
Patients without systemic disease who form hydroxyapatite and brushite stones commonly have coexistent nephrocalcinosis. Nephrocalcinosis can occur in calcium oxalate stone formers but the quantity and frequency of nephrocalcinosis in this group are dramatically less
The UAV-based test source as an end-to-end verification tool for aperture arrays
A UAV-mounted radio-frequency transmitter is proposed as a known reference field source to perform a set of functional tests on aperture arrays. The experimental results obtained on complete prototypes (end-to-end) and sub-assemblies provide good confidence on both amplitude and timing verification
Rn contamination mechanisms on acrylic surfaces
In this work, the Rn contamination mechanisms on acrylic surfaces
have been investigated. Rn can represent a significant background
source for low-background experiments, and acrylic is a suitable material for
detector design thanks to its purity and transparency. Four acrylic samples
have been exposed to a Rn rich environment for different time periods,
being contaminated by Rn and its progenies. Subsequently, the time
evolution of radiocontaminants activity on the samples has been evaluated with
and measurements, highlighting the role of different decay
modes in the contamination process. A detailed analysis of the alpha spectra
allowed to quantify the implantation depth of the contaminants. Moreover, a
study of both and measurements pointed out the Rn
diffusion inside the samples
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