Modeling dimethylsulphide production in the upper ocean

Dimethylsulphide (DMS) is produced by upper ocean ecosystems and emitted to the atmosphere, where it may have an important role in climate regulation. Several attempts to quantify the role of DMS in climate change have been undertaken in modeling studies. We examine a model of biogenic DMS production and describe its endogenous dynamics and sensitivities. We extend the model to develop a one-dimensional version that more accurately resolves the important processes of the mixed layer in determining the ecosystem dynamics. Comparisons of the results of the one-dimensional model with an empirical relationship that describes the global distribution of DMS, and also with vertical profiles of DMS in the upper ocean measured at the Bermuda Atlantic Time Series, suggest that the model represents the interaction between the biological and physical processes well on local and global scales. Our analysis of the model confirms its veracity and provides insights into the important processes determining DMS concentration in the oceans

A tool for predicting the dynamic response of biotrickling filters for VOC removal

This article presents the development of a MATLAB® computer program to simulate the performance of biotrickling filters. Since these filters behave differently during spraying and nonspraying cycles, the presented simulation tool is built on top of a mathematical description of each situation. The resulting variable-structure model is then used as the basis for simulation experiments. The model presented herein represents the first attempt to take into account the variable spraying pattern usually found in industrial installations. Overall, the software is flexible and easy to use, allowing the user to specify the emission concentration pattern, the gas concentration pattern, as well as the spraying cycle periods for up to two different emission patterns per day. The model is able to predict experimental data from a biotrickling filter treating isopropanol under intermittent conditions of loading and spraying. Simulation examples are then provided to study the effect of variable inlet concentrations and gas flow rates

A stringent preemptive protocol reduces cytomegalovirus disease in the first 6 months after kidney transplantation

Background: The optimal strategy to prevent cytomegalovirus (CMV) disease after kidney transplantation continues to be open to debate. The preemptive approach requires regular determination of CMV viremia and prompt initiation of therapy. Methods: We retrospectively compared the incidence of CMV disease during two periods at our center: A first phase (P1, n=84 kidney recipients), during which time the intensity of surveillance was determined by the responsible physician, was compared to a second phase (P2, n=74), when a stringent protocol of CMV surveillance was required for all patients. The preemptive approach was applied for all CMV risk groups; prophylaxis was optional in the case of treatment for rejection or delayed graft function in the intermediate- and high-risk group. Follow-up was truncated at 6months after transplant surgery. CMV syndrome was differentiated from asymptomatic replication by the presence of at least one systemic symptom, while diagnosis of CMV end-organ disease required histological confirmation. Results: Immunosuppression was similar in the two periods. CMV prophylaxis was used equally (26%) in both periods. The probability for asymptomatic viremia episodes was not different for patients in P1 and P2 regardless of the prevention strategy. For patients following the preemptive strategy, the probability for CMV disease was increased during P1 (p=0.016), despite fewer PCR assays being performed in phase 2. Protocol violations were only observed during P1. Conclusions: The probability of CMV disease episodes (CMV syndrome and CMV end-organ disease) was substantially reduced using a very stringent protocol. This study highlights the crucial importance of a stringent protocol with optimal adherence by all caregivers if the preemptive strategy is to be successfu

Proactively Monitoring Departmental Clinical IT Systems with an Open Source Availability System

The goal of all radiology information technology (IT) support organizations is excellent customer service through the availability of critical clinical information services, such as picture archiving communication systems and radiology information systems. Despite these goals, IT support personnel often act like firefighters, reacting to each problem, but unable to prevent or predict other problems. Proactive support is always more desirable than reactive support. Warning signs may exist well before a technical issue becomes system wide or the user is affected. The objective for IT support organizations in health care should be to maximize system uptime by using proactive monitoring systems for failures and to automatically detect failures through systems management tools. We report on the implementation of Nagios, an open source monitoring tool, as an availability management system in a diagnostic imaging department and on customized applications and protocols specific to radiology needs

Clinical value of a combined multi-phase contrast enhanced DOPA-PET/CT in neuroendocrine tumours with emphasis on the diagnostic CT component

Objective: To assess the clinical value of multi-phase, contrast-enhanced DOPA-PET/CT with emphasis on the diagnostic CT component in patients with neuroendocrine tumours (NET). Methods: Sixty-five patients with NET underwent DOPA-cePET/CT. The DOPA-PET, multi-phase CT and combined DOPA cePET/CT data were evaluated and diagnostic accuracies compared. The value of ceCT in DOPA cePET/CT concerning lesion detection and therapeutic impact was evaluated. Sensitivities, specificities and accuracies were calculated. Histopathology and clinical follow-up served as the standard of reference. Differences were tested for statistical significance by McNemar's test. Results: In 40 patients metastatic and/or primary tumour lesions were detected. Lesion-based analysis for the DOPA-PET showed sensitivity, specificity and accuracy of 66%, 100% and 67%, for the ceCT data 85%, 71% and 85%, and for the combined DOPA cePET/CT data 97%, 71% and 96%. DOPA cePET/CT was significantly more accurate compared with dual-phase CT (p < 0.05) and PET alone (p < 0.05). Additional lesion detection was based on ceCT in 12 patients; three patients underwent significant therapeutic changes based on the ceCT findings. Conclusion: DOPA cePET/CT was significantly more accurate than DOPA-PET alone and ceCT alone. The CT component itself had a diagnostic impact in a small percentage but contributed to the therapeutic strategies in selected patient

Relativistic Wavepackets in Classically Chaotic Quantum Cosmological Billiards

Close to a spacelike singularity, pure gravity and supergravity in four to eleven spacetime dimensions admit a cosmological billiard description based on hyperbolic Kac-Moody groups. We investigate the quantum cosmological billiards of relativistic wavepackets towards the singularity, employing flat and hyperbolic space descriptions for the quantum billiards. We find that the strongly chaotic classical billiard motion of four-dimensional pure gravity corresponds to a spreading wavepacket subject to successive redshifts and tending to zero as the singularity is approached. We discuss the possible implications of these results in the context of singularity resolution and compare them with those of known semiclassical approaches. As an aside, we obtain exact solutions for the one-dimensional relativistic quantum billiards with moving walls.Comment: 18 pages, 10 figure

Radiolysis of NaCl at high and low temperatures: development of size distribution of bubbles and colloids

New experimental results are presented on low temperature irradiation (18 °C) of rock-salt samples which had been exposed to initial doses up to 320 GRad at 100 °C. Differential scanning calorimetry (DSC) shows that the latent heat of melting (LHM) of sodium colloids decreases during subsequent low-temperature irradiation, whereas the stored energy (SE) increases slowly, indicating that the process of radiolysis continues. The decrease of the LHM is due to dissolution of large colloids, because the intensities of the melting peaks decrease during the second stage irradiation at low temperature. The model is formulated to describe the nucleation kinetics and the evolution of the size distribution of chlorine precipitates and sodium colloids in NaCl under high dose irradiation. It is shown that the mechanism of dissolution of large Na colloids during low temperature irradiation can be related to melting of sodium colloids.

The pancreas responds to remote damage and systemic stress by secretion of the pancreatic secretory proteins PSP/regI and PAP/regIII.

In patients with infection and sepsis serum levels of Pancreatic Stone protein/regenerating protein I (PSP) are highly elevated. The origin of PSP during these conditions is presumably the pancreas, however, an intestinal origin cannot be excluded. Similarly, pancreatitis-associated protein (PAP) was identified in the pancreas. These proteins were also localized in intestinal organs. Here we aim to elucidate the bio-distribution of PSP and PAP in animal models of sepsis and in healthy humans. PSP and PAP responded to remote lesions in rats although the pancreatic response was much more pronounced than the intestinal. Tissue distribution of PSP demonstrated a 100-fold higher content in the pancreas compared to any other organ while PAP was most abundant in the small intestine. Both proteins responded to CLP or sham operation in the pancreas. PSP also increased in the intestine during CLP. The distribution of PSP and PAP in human tissue mirrored the distribution in the murine models. Distribution of PSP and PAP was visualized by immunohistochemistry. Rats and mice underwent midline laparotomies followed by mobilization of tissue and incision of the pancreatic duct or duodenum. Standard cecum-ligation-puncture (CLP) procedures or sham laparotomies were performed. Human tissue extracts were analyzed for PSP and PAP. The pancreas reacts to remote lesions and septic insults in mice and rats with increased PSP synthesis, while PAP is selectively responsive to septic events. Furthermore, our results suggest that serum PSP in septic patients is predominantly derived through an acute phase response of the pancreas

Metabolic Changes in Skin Caused by Scd1 Deficiency: A Focus on Retinol Metabolism

We previously reported that mice with skin-specific deletion of stearoyl-CoA desaturase-1 (Scd1) recapitulated the skin phenotype and hypermetabolism observed in mice with a whole-body deletion of Scd1. In this study, we first performed a diet-induced obesity experiment at thermoneutral temperature (33°C) and found that skin-specific Scd1 knockout (SKO) mice still remain resistant to obesity. To elucidate the metabolic changes in the skin that contribute to the obesity resistance and skin phenotype, we performed microarray analysis of skin gene expression in male SKO and control mice fed a standard rodent diet. We identified an extraordinary number of differentially expressed genes that support the previously documented histological observations of sebaceous gland hypoplasia, inflammation and epidermal hyperplasia in SKO mice. Additionally, transcript levels were reduced in skin of SKO mice for genes involved in fatty acid synthesis, elongation and desaturation, which may be attributed to decreased abundance of key transcription factors including SREBP1c, ChREBP and LXRα. Conversely, genes involved in cholesterol synthesis were increased, suggesting an imbalance between skin fatty acid and cholesterol synthesis. Unexpectedly, we observed a robust elevation in skin retinol, retinoic acid and retinoic acid-induced genes in SKO mice. Furthermore, SEB-1 sebocytes treated with retinol and SCD inhibitor also display an elevation in retinoic acid-induced genes. These results highlight the importance of monounsaturated fatty acid synthesis for maintaining retinol homeostasis and point to disturbed retinol metabolism as a novel contributor to the Scd1 deficiency-induced skin phenotype

Enhancing the T-shaped learning profile when teaching hydrology using data, modeling, and visualization activities

Previous research has suggested that the use of more authentic learning activities can produce more robust and durable knowledge gains. This is consistent with calls within civil engineering education, specifically hydrology, that suggest that curricula should more often include professional perspective and data analysis skills to better develop the ‘T-shaped’ knowledge profile of a professional hydrologist (i.e., professional breadth combined with technical depth). It was expected that the inclusion of a data driven simulation lab exercise that was contextualized within a real-world situation and more consistent with the job duties of a professional in the field, would provide enhanced learning and appreciation of job duties beyond more conventional paper-and-pencil exercises in a lower division undergraduate course. Results indicate that while students learned in both conditions, learning was enhanced for the data-driven simulation group in nearly every content area. This pattern of results suggests that the use of data-driven modeling and visualization activities can have a significant positive impact on instruction. This increase in learning likely facilitates the development of student perspective and conceptual mastery, enabling students to make better choices about their studies, while also better preparing them for work as a professional in the field.This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by The Author(s) and published by Copernicus Publications on behalf of the European Geosciences Union. It can be found at: https://doi.org/10.5194/hess-20-1289-201