Naprava male površine velikog naboja za otkrivanje radioizotopa

Objective: Radionuclide imaging is used to determine the distribution of radioactively labelled radiopharmaceuticals following application to establish the anatomy affected by a variety of neoplastic, metabolic and inflammatory conditions. This is accomplished through recording radioactive emissions using a gamma camera of a SPECT system, neither of which provides high resolution. The purpose o f this investigation was to determine whether a charge-coupled device designed for intraoral radiography could be modified to detect high energy emissions made by radiopharmaceutical agents. Methods: A RadioVisioGraphy (RVG) 32000 (Trophy Radiologie, Vincennes, France) with an unsealed sensor was employed so that the scintillator could be varied. The system was further modified to be activated by a CCX timer (Trophy Radiologie, Vincennes, France) disassociated from an x-ray generator. Radionuclides tested included 125I, 133Xe, 99mTc, 1311 and 60Co. Images were attempted of metallic test objects of known outline. Images were stored in a PC-compatible computer using the proprietary software provided by Trophy Radiologie for digital dental radiography. Results: Discernible images were found with Tc-99m calibrated at 900-925 mCi. No deterioration o f the sensor occured despite the high energy of the source, hence the tungsten glass fiberoptic prism of the RVG 32000 was effective in protecting the change-coupled device (CCD) from radiation damage. Conclusions: While further studies are needed, this preliminary study shows that there is a potential fo r using small surface CCDs for the detection of radiopharmaceuticals and, hence, to better localize the distribution of deposition within small cavities such as the mouth.Ciljevi: Slikanje radionukleidima uporabljeno je da bi se odredila distribucija radioaktivno označenih radiofarmaceutskih preparata nakon njihove primjene, s namjerom da se utvrdi područje zahvaćeno tumorom, metaboličkim ili upalnim procesom. To je ostvareno tako da je biljezeno radioaktivno zračenje gama kamerom ili SPECT sustavom od kojih ni jedan ne osigurava visoku rezoluciju. Svrha ovog istraživanja bila je odrediti, da li naprava male površine velikog naboja za intraoralnu radiografiju može biti modificirana za otkrivanje zračenja jake snage stvorenog radiofarmaceutskim preparatima. Metode. Radioviziograf (RVG) naprava tipa 32000 (Trophy Radiologie, Vincennes, Francuska) s nazaštićenim senzorom rabio se, da bi se omogućilo variranje scintilatora. Sustav se i dalje modificirao da se može aktivirati putem CCX timera (Trophy Radiologie, Vincennes, Francuska) koji nije povezan s generatorom x-zraka. Testirani su radionukleidi 125I, 133Xe, 99mTc, 1311 and 60Co. Učinjene su probne slike metalnih probnih objakata poznatog obrisa. Slike su se pohranile u PC- -kompatibilnom računalu koristeći program od Trophy Radiologie za digitalnu dentalnu radiografiju. Rezultati: Vidljive slike su nađene s 99mTc kalibriranim na 900-925 mCi. Nije došlo do smanjene kakvoće senzora bez obzira na visoku energiju izvora, dakle RVG 32000 tungsten staklena fiberoptička prizma bila je efikasna u štićenju naprave male površine velikog naboja od oštećenja zračenjem. Zaključci: Iako je potrebno dalje istraživanje, ovo je preliminarno istraživanje pokazalo, da postoji mogućnost uporaba naprave male površine velikog naboja za otkrivanje radiofarmaceutika te zato do bolje lokalizacije i distribucije njihova odlaganja unutar malih šupljina poput usne šupljine

Optimum matrix acidizing: How much does it impact the productivity

Formation damage is one of the big challenges for oil and gas oilfields development. Several types of formation damage most likely exist during the entire life of producing wells. Formation damage can occur during the drilling or coring operations, well completion, work-over and production. The most important problems that affect formation during drilling operations are mud filtrate and fines invasion. There are different damage mechanisms affect reservoirs for instance pore blocking by solids, clay swelling and dispersion and liquid block which all reduce effective permeability to hydrocarbons. The reduction in production and an excessive build up pressure in injection wells indicate the formation. Many techniques are developed to remove the formation damage and to improve the productivity of wells. Matrix acidizing is one of these method which depend on injecting acids into the formation below fracturing pressure to eliminate the damage around the well. In this study, comprehensive design procedures for the acid treatment have been introduced. The procedures include the determination of the damage type and the mineralogy of the formation. Accordingly, the selection of the appropriate acid for the treatment and the optimum volume of injected acid are explained in the study. Additionally, the research presents several models for the pre-flush volume and the main acid volume based on the radius of the damaged zone and the height of the formation. New technique has been proposed for determining the final permeability improvement ratio based on current and proposed productivity index. It has been found the pre-flush volume increase as the carbonate percentage in the formation increases while the main acid volume conversely proportional with the clay content in the formation

Potential health-related phytoconstituents in leaves of Chenopodium quinoa

Background: Chenopodium quinoa Willd. or quinoa is an important food crop, having many pharmacological properties. It is recently introduced in Pakistan. In the present study, a phytochemical profile of its leaf extract was assessed through GC-MS analysis, and the health-related compounds were identified through a literature survey.Methods: Quinoa was grown in Lahore, Pakistan, and its leaves were collected at maturity, dried, ground, and extracted in methanol. GC-MS analysis of this extract was done that showed the presence of 30 compounds.Results: The most abundant compound was α-linolenic acid (12.13%), followed by n-hexadecanoic acid (11.51%), ergosta-5,7-dien-3-ol, (3β)- (10.99%), phytol (10.25%), and stigmast-7-en-3-ol, (3.beta.,5.alpha.,24S)- (7.33%). Moderately occurring compounds included DL-proline, 5-oxo-, methyl ester (6.01%), hydroxylamine, O-pentyl- (5.38%), neophytadiene (4.36%), 2-methoxy-4-vinylphenol (3.96%), 2-isopropoxyethyl propionate (3.84%), vitamin E (2.52%), and linolenic acid, methyl ester (2.46%). The remaining compounds were less abundant, having peak areas of less than 2%.Conclusion: Literature survey revealed that α-linolenic acid; n-hexadecanoic acid; phytol; squalene, vitamin E and linolenic acid, and methyl ester; present in leaf extract of quinoa possess various health-related properties such as antibacterial, antifungal, cardio-protective, anti-inflammatory, hypocholesterolemic, antihistaminic, antiandrogenic and antieczemic.                    Keywords: Amaranthaceae; Bioactive compounds; Leaf extract; Pakistan; Quinoa 

Development of polychormatic irregular waves for testing OWC bidirectional turbines at a land-based test facility

This paper presents the development of a control strategy that allows a dedicated oscillating water column turbine test facility to produce polychromatic waves. This facility allows testing of bi-directional turbines under transient conditions, validation of computational fluid dynamics simulations and testing of turbine control strategies under realistic sea states. The test facility employs a pneumatic wave generator (of unique design) to simulate the air flow of an oscillating water column. This work describes the methodology to create wave time series of various spectra that replicate a range of wave states at various geographical locations employing this rig

Central serous chorioretinopathy: Recent findings and new physiopathology hypothesis.

Central serous chorioretinopathy (CSCR) is a major cause of vision threat among middle-aged male individuals. Multimodal imaging led to the description of a wide range of CSCR manifestations, and highlighted the contribution of the choroid and pigment epithelium in CSCR pathogenesis. However, the exact molecular mechanisms of CSCR have remained uncertain. The aim of this review is to recapitulate the clinical understanding of CSCR, with an emphasis on the most recent findings on epidemiology, risk factors, clinical and imaging diagnosis, and treatments options. It also gives an overview of the novel mineralocorticoid pathway hypothesis, from animal data to clinical evidences of the biological efficacy of oral mineralocorticoid antagonists in acute and chronic CSCR patients. In rodents, activation of the mineralocorticoid pathway in ocular cells either by intravitreous injection of its specific ligand, aldosterone, or by over-expression of the receptor specifically in the vascular endothelium, induced ocular phenotypes carrying many features of acute CSCR. Molecular mechanisms include expression of the calcium-dependent potassium channel (KCa2.3) in the endothelium of choroidal vessels, inducing subsequent vasodilation. Inappropriate or over-activation of the mineralocorticoid receptor in ocular cells and other tissues (such as brain, vessels) could link CSCR with the known co-morbidities observed in CSCR patients, including hypertension, coronary disease and psychological stress

In vivo Accuracy of CCD-based Radiography for the Estimation of Periapical Lesion Dimensions

Ciljevi: Ova je klinička studija provedena da bi se usporedile točnosti procjena stomatologa o dimenzijama periapikalnih prosvjetljenja temeljenih na primjeni elektroničkoga slikanja uporabom sustava za intraoralnu radiografiju tipa RVG® 32000, te filma tipa Ektaspeed. Metode: Držeći se dozvole Nadzornoga tijela Institucije i informacija o uvjetima, napravljene su bile predoperacijske slike periapikalnih oštećenja 12 redom pridošlih pacijenata kojima je bio potreban kirurški zahvat. Slike su napravljene na oba načina: sustavom RVG® 32000, i filmom Ektaspeed. Stvarna veličina oštećenja bila je ustanovljena izradom otisaka od koštanoga voska tipa Ethicon®, tijekom same operacije. Skupina od pet stomatologa postigla je konsenzus u procjeni superiornih - inferiornih i mezio-distalnih dimenzija periapikalnih prosvjetljenja ustanovljenih iz predoperacijskih slika, odvojeno i neovisno za dva modaliteta. Rezultati: Procjene dimenzija oštećenja izrađene sustavom RVG® 32000 i filmom Ektaspeed znatno su se među se razlikovale. Odstupanje od stvarnih izmjerenih vrijednosti bilo je znatno veće za procjene temeljene na filmskim radio grafijama od odstupanja procjena na temelju slika sustava RVG® 32000. Općenito uzevši, dimenzije oštećenja bile su na osnovi filmskih slika precijenjene, a malo podcijenjene na osnovi slika snimljenih sustavom RVG® 32000. Zaključci: Digitalno intraoralno slikanje sustavom RVG® 32000 daje moguće prednosti pred konvencionalnom radiografijom time što stomatolozima omogućuje u prosjeku točnije procjene veličina periapikalnih prosvjetljenja.Objectives: This clinical study was performed to compare the accuracy of endodontists ’ assessment o f the sizes o f periapical radiolucencies using electronic imaging with the RVG® 32000 intraoral radiographic system and Ektaspeed film. Methods: Following Institutions Review Board approval and informed consent, presurgical images were made both with the RVG® 32000 and Ektaspeed film for periapical lesions in 12 consecutive patients requiring endodontic surgery. Actual lesion size was determined by making impressions with Ethicon® bone wax at the time of surgery. A panel o f five endodontists reached consensus in estimation of the superior- inferior and mesio-distal dimensions of the periapical radiolucencies from the presurgical images, separately and independently for two modalities. Results: Lesion dimension estimates were significantly different between images made with the RVG® 32000 Ektaspeed film. There was a much greater deviation from the measured actual values for estimates using film radiographs than for those for the RVG® 32000 images. Generally, there was an over-estimation o f lesion size with film, and a slight under-estimation with RVG® 32000 images. Conclusions: Digital intraoral imaging with the RVG® 32000 offers potential advantages over conventional radiography in permitting endodontists on average to more accurately estimate the size of periapical radiolucencies

Spatial variation in directional swimming enables juvenile sea turtles to reach and remain in productive waters

Ocean currents play an important role in the movement and distribution of organisms and for small animals it is often assumed that their movements in the ocean are determined by passive drift. Here we challenge this assumption by conducting an experiment at the scale of an entire ocean basin to test whether small (∼35 cm) juvenile loggerhead sea turtles Caretta caretta move independently of ocean currents. By comparing the trajectories of 46 satellite tracked turtles (11502 positions, 12850 tracking days) with Lagrangian drifters (3716303 positions, 927529 tracking days) and virtual particles tracked within the Hybrid Coordinate Ocean Model (HYCOM), we found that in certain areas turtles moved in a similar manner to ocean currents, but in other areas turtle movement was markedly different from ocean currents, with turtles moving to areas thousands of kilometres from where they would have drifted passively. We further found that turtles were distributed in more-productive areas than would be expected if their movement depended on passive transport only. These findings demonstrate that regional variation in directional swimming contributes to young sea turtles reaching more favourable developmental habitats and supports laboratory work suggesting that young turtles have a map sense to determine their location in a seemingly featureless ocean

The endothelial mineralocorticoid receptor regulates vasoconstrictor tone and blood pressure

Pathophysiological aldosterone (aldo)/mineralocorticoid receptor (MR) signaling has significant effects on the cardiovascular system, resulting in hypertension and cardiovascular remodeling; however, the specific contribution of the vascular MR to blood pressure regulation remains to be established. To address this question, we generated a mouse model with conditional overexpression of the MR in endothelial cells (MR-EC). In basal conditions, MR-EC mice developed moderate hypertension that could be reversed by canrenoate, a pharmacological MR antagonist. MR-EC mice presented increased contractile response of resistance arteries to vasoconstrictors (phenylephrine, thromboxane A(2) analog, angiotensin II, and endothelin 1) in the absence of vascular morphological alterations. The acute blood pressure response to angiotensin II or endothelin 1 infusion was increased in MR-EC mice compared with that in littermate controls. These observations demonstrate that enhanced MR activation in the endothelium generates an increase in blood pressure, independent of stimulation of renal tubular Na(+) transport by aldo/MR or direct activation of smooth muscle MR and establish one mechanism by which endothelial MR activation per se may contribute to impaired vascular reactivity

SPIRONOLACTONE FOR NONRESOLVING CENTRAL SEROUS CHORIORETINOPATHY: A RANDOMIZED CONTROLLED CROSSOVER STUDY.

PURPOSE: To evaluate the effect of spironolactone, a mineralocorticoid receptor antagonist, for nonresolving central serous chorioretinopathy. METHODS: This is a prospective, randomized, double-blinded, placebo-controlled crossover study. Sixteen eyes of 16 patients with central serous chorioretinopathy and persistent subretinal fluid (SRF) for at least 3 months were enrolled. Patients were randomized to receive either spironolactone 50 mg or placebo once a day for 30 days, followed by a washout period of 1 week and then crossed over to either placebo or spironolactone for another 30 days. The primary outcome measure was the changes from baseline in SRF thickness at the apex of the serous retinal detachment. Secondary outcomes included subfoveal choroidal thickness and the ETDRS best-corrected visual acuity. RESULTS: The mean duration of central serous chorioretinopathy before enrollment in study eyes was 10 ± 16.9 months. Crossover data analysis showed a statistically significant reduction in SRF in spironolactone treated eyes as compared with the same eyes under placebo (P = 0.04). Secondary analysis on the first period (Day 0-Day 30) showed a significant reduction in subfoveal choroidal thickness in treated eyes as compared with placebo (P = 0.02). No significant changes were observed in the best-corrected visual acuity. There were no complications related to treatment observed. CONCLUSION: In eyes with persistent SRF due to central serous chorioretinopathy, spironolactone significantly reduced both the SRF and the subfoveal choroidal thickness as compared with placebo