Multiparametric magnetic resonance imaging of the prostate-a basic tutorial.

Prostate cancer is the second most common cause of cancer related death in the United States and the most commonly diagnosed malignancy in men. In general, prostate cancer is slow growing, though there is a broad spectrum of disease that may be indolent, or aggressive and rapidly progressive. Screening for prostate is controversial and complicated by lack of specificity and over diagnosis of clinically insignificant cancer. Imaging has played a role in diagnosis of prostate cancer, primarily through systemic transrectal ultrasound (TRUS) guided biopsy. While TRUS guided biopsy radically changed prostate cancer diagnosis, it still remains limited by low resolution, poor tissue characterization, relatively low sensitivity and positive predictive value. Advances in multiparametric magnetic resonance imaging (mpMRI) have allowed more accurate detection, localization, and staging as well as aiding in the role of active surveillance (AS). The use of mpMRI for the evaluation of prostate cancer has increased dramatically and this trend is likely to continue as the technique is rapidly improving and its applications expand. The purpose of this article is to review the basic principles of mpMRI of the prostate and its clinical applications, which will be reviewed in greater detail in subsequent chapters of this issue

Extreme Wave Loading on Offshore Wave Energy Devices using CFD

Two commercial Navier-Stokes solvers are applied to wave-wave and wave-structure interaction problems leading to the final application of simulating a single float of the wave energy converter (WEC) Manchester Bobber in extreme waves and a fixed section of the Pelamis in regular waves. First the two software packages CFX and STAR CCM+ are validated against measured results from physical tank tests concerning the interaction of 3 non-linear focused wave groups of different steepness (Ning et al. 2007). The agreement for all of these cases is very good and could even be improved from first order to second order wave setup at the wavemaker. However, in preliminary regular wave tests, the damping of the waves is identified to be an issue, which is the reason for focusing the waves and placing the structures in the following experiments approximately one wavelength behind the wavemaker. The interaction of fixed vertical and horizontal cylinders in regular waves are simulated concerning the forces on the structures (Kriebel 1998, Dixon et al. 1979). For the horizontal cylinder non-linear force oscillations of double the wave frequency could be modelled in good agreement with physical tank data, where linearised models failed. For the vertical cylinder the problem of the secondary load cycle due to a backward-breaking wave behind the cylinder is of special interest (Stansberg 1997, Chaplin et al. 1997). Here, the horizontal forces on a slender cylinder with a diameter approximately equal to the wave height are simulated successfully. Furthermore, the highly non-linear wave run-up in front of the cylinder is resolved well in the numerical approach. The next set of simulations includes rigid body motion. Here, the forced oscillations of a cone shaped body near the still water surface is simulated. These results are compared with test data published by Drake et al. (2008). For these cases the non-linearity of the experiments is discussed by comparing the sum and differences of the force and surface elevation time histories for a set of simulations with opposite excursion of the cone. The hydrodynamic forces on the cone surface are resolved in very good agreement. The solution of the surface elevation close to the cone surface is also resolved reasonably well. After having validated the codes for fixed wave-structure interaction problems and forced motion, the CFD methods are finally applied to problems relevant to the survivability of WECs. First a single float in waves is modelled. This challenging case combines the extreme wave setup with a floating body problem in one and two degrees of freedom including the interaction of the float inertia with the inertia of a separate mass attached to it. The vertical translations of the float are compared with physical tank tests by Stallard et al. (2008). This case clearly demonstrates the capabilities and challenges in using CFD to simulate WECs. When representing the pulley and counterweight system by a simplified external body force rather than the full setup, the calculated translations of the float agreed better with the measured results from the physical tank test. Furthermore the codes are used to simulate a single fixed section of the Pelamis device in regular waves. The surface elevations close to the device are discussed and the forces acting on different strips on the structure are presented

The loss of HMAS Sydney II: medical aspects

On 19 November 1941, HMAS Sydney was 100nm off Shark Bay, on her way back to Fremantle after escorting the troopship Zealandia to Sunda Strait, between Java and Sumatra. At 1600 she encountered the German auxiliary cruiser Kormoran. The ensuring battle began at 1730 and ended at 1825. Sydney was last seen on fire at 2300 while Kormoran was scuttled and sank just after midnight. There were 318 survivors from Kormoran’s crew of 399, but no survivors from Sydney’s crew of 645. Both wrecks were found in March 2008 and this led to a Commission of Inquiry to address the various controversies and conspiracy theories related to Sydney’s loss

Quantifying Carbon Dioxide and Methane Fluxes from Sargassum Strandings on Florida Beaches

Floating Sargassum is thought to be a sink of blue carbon in that it removes carbon dioxide (CO2) from the atmosphere and sequesters organic carbon by sinking into the deep ocean or being buried in sediments. However, Sargassum that washes into intertidal ecosystems will eventually decompose, releasing greenhouse gases to the surrounding air, groundwater, and surface coastal seawater. In recent years, Sargassum strandings have increased in the Atlantic Ocean, making our understanding of the fate of beached Sargassum critical for determining how much carbon is sequestered by the seaweed. This study investigated greenhouse gas fluxes of decaying Sargassum wrack in mesocosm experiments to understand how beached Sargassum could affect the coastal carbon cycle. GHG fluxes were investigated in two mesocosm experiments, simulating (1) tidal seawater inundation of Sargassum wrack and (2) wrack decomposing in oxygen restricted and aerated conditions. Measurements of greenhouse gas fluxes from naturally decomposing Sargassum were also undertaken. Overall, strong CO2 fluxes were recorded with weak or inconsistent CH4 fluxes. Simulated tidal conditions and simulated hypoxic conditions did not lead to differences in GHG fluxes, though dry conditions did have greater CO2 fluxes than seawater immersion conditions. Over the course of the experiment, alkalinity in seawater mesocosms increased, likely due to anaerobic chemical pathways. In-situ incubations of stranded Sargassum returned strong CO2 and CH4 fluxes, although it is unclear whether these were due to the wrack itself or underlying sediment biogeochemical processes

Effects of pH and muscle type on the viscoelastic and water-holding properties during heat-induced gelation of porcine myofibrillar proteins

The gelation characteristics of myofibrillar protein have impact on the final texture of meat products. Understanding the gelation mechanism of meat gel systems is beneficial for the development of processed meat products as well as maintaining quality and consistency in meat processing. The aim of this study was to investigate the impact of pH (5.6, 6.0, 6.5, and 7.0) and muscle type (psoas major (predominately glycolytic), semimembranosus (less glycolytic) and longissimus dorsi (less glycolytic) all at pH 6.0 and 6.5) on the heat-induced gelation properties of myofibrillar proteins from porcine muscle. Dynamic rheological properties were measured while heating at 10C/min from 20-850C, followed by a holding phase at 850C for 3 minutes and a cooling phase from 850C to 50C at a rate of 50C/min. Storage modulus (G)́ increased as gel formation occurred, but decreased after reaching the temperature of myosin denaturation (520C) until approximately 600C when the gel strength increased again. This resulted in a peak and subsequent depression in the thermogram. This depression in the curve was more pronounced with increasing pH. Results indicate protein denaturation and gel formation are pH dependent. Testing muscle type at 2 pH values showed that semimembranosus produces the strongest gels at temperatures greater than 600C. Stronger gels formed in samples of pH 6.0 than the sample of pH 6.5 from the same muscle. Strong correlations were identified between storage modulus from muscle type treatments at 57, 72, 85 and 50C. It is clear the variation in gel strength is determined prior to reaching 570C. Muscle type and pH were found to influence water-holding capacity. It was determined that muscle type influenced water-holding capacity to a greater degree than varying pH from 6.0 to 6.5

Development of topographic maps and rear steering control for an agricultural vehicle through incorporation of posture and attitude measurements

The two articles contained in this work investigate the relationship between an agricultural vehicle\u27s posture and attitude with (a) its surroundings and (b) machine performance. In the first case, a self-propelled agricultural sprayer was equipped with four RTK DGPS receivers and an inertial measurement unit (IMU) to measure vehicle attitude and field elevation as the vehicle was driven across a field. Data was collected in a stop-and-go fashion as well as at three different speeds on a field area with varying topography. Using ordinary kriging, digital elevation models (DEMs) were interpolated from the elevation measurements and elevation plus attitude measurements. The resulting DEMs were compared to each other to evaluate the effect of including attitude measurement on DEM accuracy. At the widest swath width, the DEMs generated with attitude measurements had substantially lower error measures than those DEMs generated without attitude measurements. These results provide evidence that support the feasibility of using vehicle-based measurements collected during typical field operations for accurate DEM development. In the second case, a steering controller was designed and implemented on a self-propelled agricultural sprayer with four-wheel steering (4WS). The goals of this controller were to reduce the off-tracking error of the rear wheels and control turning radius during lateral shifts to reduce chemical application error. The vehicle was driven along marked courses of different shapes to test the steering controller\u27s performance. A computer simulation provided an estimate of chemical application rates across the spray boom during lateral shift maneuvers. During hillside operations, the controller was able to reduce the area damaged by the rear wheels from 107.35 m2 using two-wheel steer (2WS) to 0.32 m2 with Active Rear Steering (ARS) control. During 90-degree turns, the controller reduced the area damaged by rear wheels from 49.34 m2 in 2 WS to 1.15 m2 with ARS. This reduction in rear wheel off-tracking could lead to a reduction in crop damage through turns and during hillside operation, as well as reduced chemical application errors during turns

An Investigation of Registered Nurses’ Knowledge and Decision-Making Processes In Relation to the Management of Adults With Diabetic Ketoacidosis

Introduction: Diabetic ketoacidosis (DKA) is an acute complication of diabetes. Registered nurses (RNs) knowledge with regard to DKA has never been investigated in any depth, nor has their decision making ever been examined in this specific context. Research Significance: Nursing research literature acknowledges that nurses have an important role in the management of patient with DKA. However, there is very little empirical evidence available to support this claim. The purpose of this study is to provide evidence of the level of knowledge, the decision-making processes and the factors that influence nurses’ decision making whilst managing patients with DKA. Methodology: A sequential mixed methods design in four phases was used. An online survey was developed and tested for clarity, internal consistency, content validity and reliability. The survey was administered to nurses who were likely to have been involved in the care of patients with DKA in their clinical practice and the data analysed using descriptive statistics. Semi-structured interviews were then conducted based on the results of the survey. Finally, both data sets were amalgamated in a mixed methods analysis to develop recommendations for future research and clinical practice. Results: The survey results indicate that RNs had varying levels of knowledge in relation to DKA and strengths and weaknesses at different stages of their decision-making process. Some of the knowledge deficits related to policy, pharmacology and psychosocial issues. Four themes emerged from the qualitative data relating to the factors that influence RNs decision making whilst managing patients with DKA including policy, staffing, patients and confidence. The mixed methods analysis resulted in a number of recommendations for xix organisational and education strategies to enables RNs to provide holistic and evidence-based care to patients with DKA. Conclusion: This study found that RNs were generally able to demonstrate adequate levels of knowledge to manage patients with DKA and utilised all the stages of the Clinical Judgment Model when making decisions. It was found that the most significant knowledge gaps related to information directly out of the hospital policy, which nurses found served as both an enabler and a barrier to their decision making. There were a number of limitations in this study, many relating to the COVID-19 pandemic. The participants requested a flow chart be developed to aid their knowledge application and decision-making practices whilst managing these acutely unwell and complex patients

Valuation of Sovereign Debt with Strategic Defaulting and Rescheduling

This paper provides a simple model of the rescheduling of debt following a sovereign default as a bond exchange. In case of default, the sovereign offers a new bond with lower coupon and principal.The debtors accept the offer if the value of the new bonds is higher than the proceedings of the litigation of the sovereign. Both the default decision of the sovereign as well as the exchange offer are modeled endogenously and in closed form. The resulting formulas for bond value and credit spreads are in closed form as well. The analysis yields credit spread curves similar to corporate credit curves: For high risk issuers, i.e.,sovereign with low country wealth relative to debt level,and high litigation costs,the credit spread curves are “hump ”-shaped. Better quality issues exhibit increasing credit spread curves. The numerical analysis with reasonable parameters yields credit spreads of a size compatible to market spreads. A comparison to corporate debt supports the stylized fact that, using the same parameters,corporate debt is less risky than sovereign debt since the threat of liquidation is stronger than the threat of litigation.Sovereign Debt; Debt pricing; Bond Exchange Offers