Study of Radiophotoluminescence of Eu Doped CaSO4 Phosphor for Gamma Dosimetric Applications

CaSO4:Eu phosphor is synthesised by acid distillation method with varying synthesis parameters for studying its Radiophotoluminescence (RPL) properties for gamma absorbed dose measurements. Five phosphor samples are prepared by varying quantity of solvent, distillation temperature and reaction time. XRD, SEM, particle size analysis and photoluminescence studies are carried out. The characterisation study shows polycrystalline luminescent particles of average size varying from 35 μm to 55 μm. Characteristic emission of Eu3+ is observed around 590, 615 and 620 nm at 242 nm excitation. Gamma dose response of maximum Eu3+ PL intensity sample is studied in the range 10 cGy to 1000 cGy using Co-60 source. Gamma radiation exposure induces conversion of Eu3+ to Eu2+ giving luminescence at 385 nm with 320 nm excitation. Repetitive measurements of gamma exposed samples are carried out and no significant fading is observed within one week of post-irradiation. The phosphor has the potential to be used for gamma dosimetry

Organizing recurrent network dynamics by task-computation to enable continual learning

Biological systems face dynamic environments that require continual learning. It is not well understood how these systems balance the tension between flexibility for learning and robustness for memory of previous behaviors. Continual learning without catastrophic interference also remains a challenging problem in machine learning. Here, we develop a novel learning rule designed to minimize interference between sequentially learned tasks in recurrent networks. Our learning rule preserves network dynamics within activity-defined subspaces used for previously learned tasks. It encourages dynamics associated with new tasks that might otherwise interfere to instead explore orthogonal subspaces, and it allows for reuse of previously established dynamical motifs where possible. Employing a set of tasks used in neuroscience, we demonstrate that our approach successfully eliminates catastrophic interference and offers a substantial improvement over previous continual learning algorithms. Using dynamical systems analysis, we show that networks trained using our approach can reuse similar dynamical structures across similar tasks. This possibility for shared computation allows for faster learning during sequential training. Finally, we identify organizational differences that emerge when training tasks sequentially versus simultaneously

The need for calcium imaging in nonhuman primates: New motor neuroscience and brain-machine interfaces

A central goal of neuroscience is to understand how populations of neurons coordinate and cooperate in order to give rise to perception, cognition, and action. Nonhuman primates (NHPs) are an attractive model with which to understand these mechanisms in humans, primarily due to the strong homology of their brains and the cognitively sophisticated behaviors they can be trained to perform. Using electrode recordings, the activity of one to a few hundred individual neurons may be measured electrically, which has enabled many scientific findings and the development of brain-machine interfaces. Despite these successes, electrophysiology samples sparsely from neural populations and provides little information about the genetic identity and spatial micro-organization of recorded neurons. These limitations have spurred the development of all-optical methods for neural circuit interrogation. Fluorescent calcium signals serve as a reporter of neuronal responses, and when combined with post-mortem optical clearing techniques such as CLARITY, provide dense recordings of neuronal populations, spatially organized and annotated with genetic and anatomical information. Here, we advocate that this methodology, which has been of tremendous utility in smaller animal models, can and should be developed for use with NHPs. We review here several of the key opportunities and challenges for calcium-based optical imaging in NHPs. We focus on motor neuroscience and brain-machine interface design as representative domains of opportunity within the larger field of NHP neuroscience

A Multisectoral Approach in Dengue Management in Seremban Malaysia: an Ecobiosocial Perspective

Background: Dengue has been established as a major public health issue in many parts of the world particularly those in the tropical regions. In Malaysia, the rising rate of dengue cases had remained uncurbed, alarming to both the public and the local authorities. Despite the existence of legislations and control activities, why does the number of dengue cases keep on increasing every year? The objective of this study was to assess the existing environmental and health policies/strategies towards sustainable prevention and control of dengue/DHF in Malaysia. In addition, it also aimed to review the eco-bio-social approach and its advantages in prevention and control of dengue. Subjects and Method: Series of in-depth interviews were conducted on 12 key- informants aged between 36-58 years old. They were selected based on their roles that were divided into three categories, i.e. (1) policy makers, (2) middle managers, and (3) implementers at the ground level. Each interview explored in detail, on the important domains which were the ecology, biology, and social factors. Each session took an average of 45 minutes to 1 hour. There were a total of 10 males and 2 females selected for the in-depth interview. Open-ended questions were asked and the interviews were voice recorded, after obtaining consent from the respondents. The interviews were terminated once data saturation was achieved. The qualitative data was analyzed using Atlas.ti software. Results: The three main themes that emerged and were identified to contribute to sustainable dengue control and prevention were (1) adequate implementation of existing health policy, (2) good integration and coordination between agencies, (3) commitment from political and community leaders. Local data showed that areas which did not have these important components became hot spots for dengue with high number of dengue cases. Conclusion: It is vital that the community and relevant authorities focus on these themes/domains that will significantly improve the chances of having sustainable denguecontrol and management program in their localities. Keywords: multisectoral approach, ecobiosocial, engue control, sustainable managemen

F(T) Models within Bianchi Type I Universe

In this paper, we consider spatially homogenous and anisotropic Bianchi type I universe in the context of F(T) gravity. We construct some corresponding models using conservation equation and equation of state parameter representing different phases of the universe. In particular, we take matter dominated era, radiation dominated era, present dark energy phase and their combinations. It is found that one of the models has a constant solution which may correspond to the cosmological constant. We also derive equation of state parameter by using two well-known F(T) models and discuss cosmic acceleration.Comment: 19 pages, accepted for publication in Mod. Phys. Lett.

Ultrazvučna procjena reakcije jajnika nakon primjene mjera svjetlosnoga režima u deva (Camelus dromedarius).

The present study was carried out with two objectives, (a) the use of ultrasound scanners to study the effect of ‘mask on eyes’ as a photoperiodic control measure for folliculogenesis in female camels, (b) Use of blood progesterone assays to monitor ovarian changes in camels. Fourteen female camels aged 7-11 years were used for the present experiment. Seven were studied for the effect of a mask over the eyes (for six hours daily) as a photoperiodic control measure on ovarian activity and the remaining seven were kept as controls. Ovaries were examined by ultrasound at weekly intervals for seven weeks during the non-breeding season. Camels were mated with virile stud when a follicle (≥0.9 cm diameter, ovulating size) was visible on either of the ovaries. Ovaries were monitored for ovulation up to 48 h post-mating by ultrasound at 12 hourly intervals and at 20, 30 and 40 days post mating to ascertain pregnancy. A commercially available RIA kit was used for serum progesterone assay on samples obtained at 0, 7, 15, 30 and 45 days of mating. No follicle was observed in camels before treatment and in treated (masked) or untreated camels during the first week of treatment. By the third week 100% camels in the treatment group evidenced measurable small follicles (0.5-0.89 cm, 6/7) or follicles of ovulating size (≥0.9 cm, 1/7). Follicles of ovulating size were observed in 28.6, 14.3, 14.3 and 14.3 percent camels by 4th, 5th, 6th and 7th week of treatment. Fifty percent (3/6) of the camels became pregnant. The serum plasma progesterone level increased after ovulation and remained higher than 1.0 ng/mL in pregnant camels. In the control group one camel showed a follicle (0.6 cm diameter) at the 5th week, which did not reach ovulating size. The results of the present study indicate that protecting eyes from sunlight one or two months ahead of the breeding season stimulates follicular growth in camels and pregnancy can occur in these camels when mated.Istraživanje je provedeno u svrhu ultrazvučnoga praćenja utjecaja svjetlosnoga razdoblja kontroliranog pomoću maske na očima na tijek i dinamiku folikulogeneze u deva i određivanja razine progesterona za praćenje cikličnih promjena na jajnicima. Promatrano je 14 deva u dobi od sedam do 11 godina koje su bile podijeljene u pokusnu (n = 7) i kontrolnu skupinu (n = 7). Devama u kontrolnoj skupini svakodnevno je stavljana maska na oči tijekom 6 sati u razdoblju od 7 tjedana izvan rasplodne sezone. Deve su ultrazvučno pregledavane jednom tjedno za vrijeme čitavoga trajanja istraživanja. One su bile parene s plodnim mužjakom kad je uočen folikul na jajniku (≥0,9 cm promjera, ovulacijski folikul). Kad je uočen ovulacijski folikul, jajnici su bili pregledavani ultrazvukom svakih 12 sati u razdoblju od 48 sati radi potvrđivanja ovulacije, a potom nakon 20, 30 i 40 dana radi potvrđivanja gravidnosti. Uzorci krvi bili su uzeti 0., 7., 15., 30. i 45. dana nakon parenja, a plazma je bila analizirana komercijalnim RIA kompletom za određivanje koncentracije progesterona. Prije početka istraživanja i tijekom prvog tjedna istraživanja nijedna deva nije imala folikule na jajnicima. Do trećega tjedna istraživanja, uočeni su folikuli u svih deva pokusne skupine, ali su većinom bili maloga promjera (0,5 - 0,89 cm, 6/7), osim u jedne deve u koje je folikul bio ovulacijske veličine (>0,9 cm). Folikuli koji su po veličini odgovarali ovulacijskim folikulima ustanovljeni su u 28,6% deva tijekom 4. tjedna, 14,3% tijekom 5. tjedna, 14,3% tijekom 6. i 14,3% deva tijekom 7. tjedna istraživanja. Koncipiralo je 50% deva (3/6). Razina progesterona u krvi porasla je nakon ovulacije i bila je veća od 1 ng/ml u svih gravidnih deva. U kontrolnoj skupini samo je jedna deva imala folikul (0,6 cm) na jajniku tijekom 5. tjedna, ali on nije dosegnuo ovulacijsku veličinu. Rezultati istraživanja pokazuju da zaštita očiju od svjetlosti mjesec do dva prije sezone parenja potiče razvoj folikula u deva i može dovesti do gravidnosti ako se deve tada par

A Universal Marginalizer for Amortized Inference in Generative Models

We consider the problem of inference in a causal generative model where the set of available observations differs between data instances. We show how combining samples drawn from the graphical model with an appropriate masking function makes it possible to train a single neural network to approximate all the corresponding conditional marginal distributions and thus amortize the cost of inference. We further demonstrate that the efficiency of importance sampling may be improved by basing proposals on the output of the neural network. We also outline how the same network can be used to generate samples from an approximate joint posterior via a chain decomposition of the graph

Techniques, Clinical Applications and Limitations of 3D Reconstruction in CT of the Abdomen

Enhanced z-axis coverage with thin overlapping slices in breath-hold acquisitions with multidetector CT (MDCT) has considerably enhanced the quality of multiplanar 3D reconstruction. This pictorial essay describes the improvements in 3D reconstruction and technical aspects of 3D reconstruction and rendering techniques available for abdominal imaging. Clinical applications of 3D imaging in abdomen including liver, pancreaticobiliary system, urinary and gastrointestinal tracts and imaging before and after transplantation are discussed. In addition, this article briefly discusses the disadvantages of thin-slice acquisitions including increasing numbers of transverse images, which must be reviewed by the radiologist

Autoimmune Pancreatitis Exhibiting Multiple Mass Lesions

Our case is a first report of autoimmune pancreatitis with multiple masses within the pancreas which was pathologically diagnosed by endoscopic ultrasound-guided fine needle aspiration and treated by steroid. The masses disappeared by steroid therapy. Our case is informative to know that autoimmune pancreatitis sometimes exhibits multiple masses within the pancreas and to diagnose it without unnecessary surgery

MicroRNAs targeting oncogenes are down-regulated in pancreatic malignant transformation from benign tumors

BACKGROUND MicroRNA (miRNA) expression profiles have been described in pancreatic ductal adenocarcinoma (PDAC), but these have not been compared with pre-malignant pancreatic tumors. We wished to compare the miRNA expression signatures in pancreatic benign cystic tumors (BCT) of low and high malignant potential with PDAC, in order to identify miRNAs deregulated during PDAC development. The mechanistic consequences of miRNA dysregulation were further evaluated. METHODS Tissue samples were obtained at a tertiary pancreatic unit from individuals with BCT and PDAC. MiRNA profiling was performed using a custom microarray and results were validated using RT-qPCR prior to evaluation of miRNA targets. RESULTS Widespread miRNA down-regulation was observed in PDAC compared to low malignant potential BCT. We show that amongst those miRNAs down-regulated, miR-16, miR-126 and let-7d regulate known PDAC oncogenes (targeting BCL2, CRK and KRAS respectively). Notably, miR-126 also directly targets the KRAS transcript at a "seedless" binding site within its 3'UTR. In clinical specimens, miR-126 was strongly down-regulated in PDAC tissues, with an associated elevation in KRAS and CRK proteins. Furthermore, miR-21, a known oncogenic miRNA in pancreatic and other cancers, was not elevated in PDAC compared to serous microcystic adenoma (SMCA), but in both groups it was up-regulated compared to normal pancreas, implicating early up-regulation during malignant change. CONCLUSIONS Expression profiling revealed 21 miRNAs down-regulated in PDAC compared to SMCA, the most benign lesion that rarely progresses to invasive carcinoma. It appears that miR-21 up-regulation is an early event in the transformation from normal pancreatic tissue. MiRNA expression has the potential to distinguish PDAC from normal pancreas and BCT. Mechanistically the down-regulation of miR-16, miR-126 and let-7d promotes PDAC transformation by post-transcriptional up-regulation of crucial PDAC oncogenes. We show that miR-126 is able to directly target KRAS; re-expression has the potential as a therapeutic strategy against PDAC and other KRAS-driven cancers