Low-temperature coupling of methane

Methane is the main component of natural gas and its utilization amounts to ca. 1.7 109 tons of oil equivalent per year [1]. Since the present reserve of methane is located in remote places, its transportation is a major problem. Methane coupling to form C2+ hydrocarbons is, therefore, of a primary importance because before transportation methane should be converted into hydrocarbons with higher boiling points, such as ethane, propane, etc. The catalytic conversion of methane can be carried out in several ways which have excellently been reviewed in Refs. 1 and 2. Basically, three routes exist: (i) the indirect route in which methane is first converted into syngas in presence of water (steam reforming), CO2 (carbon dioxide reforming), or oxygen (partial oxidation) and the resultant syngas can be utilized in the traditional way; (ii) direct coupling in the presence of oxygen (oxidative coupling of methane, OCM) or hydrogen (two-step polymerization); and (iii) direct conversion in the presence of oxygen to oxygenates (CH3OH, HCOH), in the presence of Cl2, HCI to methane chlorides, in the presence of ammonia to HCN, etc

Imaging oligometastatic cancer before local treatment

The term oligometastases is in common clinical use, but remains poorly defined. As novel treatment strategies widen the therapeutic window for patients defined as having oligometastatic cancer, improved biomarkers to reliably define patients who benefit from these treatments are needed. Multimodal imaging should be optimized to comprehensively assess the metastatic sites, disease burden and response to neoadjuvant treatment in each disease setting. These features will likely remain important prognostic biomarkers, and are critical in planning multidisciplinary treatment. There are opportunities to extract additional phenotypic information from conventional imaging, while novel imaging techniques can also image specific aspects of tumour biology. Imaging can both characterise and localise the phenotypic heterogeneity of multiple tumour sites. Novel approaches to existing imaging datasets, and correlation with tumour biology, will be important in realizing the potential of imaging to guide treatment in the oligometastatic setting. This article discusses the current status and future directions of imaging in patients with extracranial oligometastases

Generator Coordinate Calculations for the Breathing-Mode Giant Monopole Resonance in Relativistic Mean Field Theory

The breathing-mode giant monopole resonance (GMR) is studied within the framework of the relativistic mean-field theory using the Generator Coordinate Method (GCM). The constrained incompressibility and the excitation energy of isoscalar giant monopole states are obtained for finite nuclei with various sets of Lagrangian parameters. A comparison is made with the results of nonrelativistic constrained Skyrme Hartree-Fock calculations and with those from Skyrme RPA calculations. In the RMF theory the GCM calculations give a transition density for the breathing mode, which resembles much that obtained from the Skyrme HF+RPA approach and also that from the scaling mode of the GMR. From the systematic study of the breathing-mode as a function of the incompressibility in GCM, it is shown that the GCM succeeds in describing the GMR energies in nuclei and that the empirical breathing-mode energies of heavy nuclei can be reproduced by forces with an incompressibility close to $K = 300$ MeV in the RMF theory.Comment: 27 pages (Revtex) and 5 figures (available upon request), Preprint MPA-793 (March 1994

Commentary: how will interventional oncology navigate the "valleys of death" for new medical devices?

Whereas clinical trials of cancer drugs have methodological standards and conventional primary endpoints, these are not necessarily applicable to the clinical development of loco-regional treatments and new medical devices. The current challenge is to generate high-level clinical evidence for loco-regional treatments to define the benefits for patients. In this article, we argue that, to generate convincing evidence of clinical efficacy and safety, the collective coherence of the entire data package is often more important than the primary endpoint of one clinical trial. We also propose that, when a comprehensive clinical data package is not feasible, limited clinical data can be supplemented with other types of evidence. Emerging life science companies often define the "valley of death" after securing initial investment to translate an early medical device concept to a development stage that is attractive to funders. Unfortunately for this industry, there is a second "valley of death" if the focus and goal is only regulatory approval, to the neglect of clinical acceptance and reimbursement. For the emerging specialism of interventional oncology, it is critical to plan a clear line of sight for each new medical device to avoid the valleys of death and to demonstrate the clinical benefit. Increased international guidance to establish realistic yet convincing standards in this area may avoid attrition of potentially beneficial devices and therapeutic procedures in the valleys of death

Cushing’s syndrome: Epidemiology and developments in disease management

Cushing’s syndrome is a rare disorder resulting from prolonged exposure to excess glucocorticoids. Early diagnosis and treatment of Cushing’s syndrome is associated with a decrease in morbidity and mortality. Clinical presentation can be highly variable, and establishing the diagnosis can often be difficult. Surgery (resection of the pituitary or ectopic source of adrenocorticotropic hormone, or unilateral or bilateral adrenalectomy) remains the optimal treatment in all forms of Cushing’s syndrome, but may not always lead to remission. Medical therapy (steroidogenesis inhibitors, agents that decrease adrenocorticotropic hormone levels or glucocorticoid receptor antagonists) and pituitary radiotherapy may be needed as an adjunct. A multidisciplinary approach, long-term follow-up, and treatment modalities customized to each individual are essential for optimal control of hypercortisolemia and management of comorbidities

Comorbidities in Cushing’s disease

Introduction: Cushing’s disease is a rare disorder characterized by overproduction of ACTH from a pituitary adenoma leading to hypercortisolemia that in turn leads to increased morbidity and mortality.Methods: Here we review the comorbidities associated with Cushing’s disease and their impact on quality of life and mortality.Results: Recent evidence suggests that correction of hypercortisolemia may not lead to complete resolution of comorbidities associated with this condition. In particular, increased cardiovascular risk may persist despite long-term remission of hypercortisolemia. This may be related to persistence of visceral adiposity, adverse adipokine profile, glucose intolerance, hypertension, dyslipidemia, atherosclerosis and a procoagulant phenotype. Prior prolonged exposure to glucocorticoids also may have irreversible effects on the central nervous system, leading to persistent cognitive and mood alterations. Osteoporosis and fractures, especially vertebral fractures, can further add to morbidity and a poor quality of life. Normalization of cortisol levels leads to significant improvement in comorbidities but long-term data regarding complete resolution are lacking and need further study.Conclusion: Early diagnosis and treatment of hypercortisolemia, aggressive management of comorbidities along with long-term follow-up is crucial for the optimal recovery of these patients

Enhanced Spin Dependent Shot Noise in Magnetic Tunnel Barriers

We report the observation of enhanced spin dependent shot noise in magnetic tunnel barriers, suggesting transport through localized states within the barrier. This is supported by the existence of negative magnetoresistance and structure in the differential conductance curves. A simple model of tunneling through two interacting localized states with spin dependent tunneling rates is used to explain our observations.Comment: 8 pages, 8 figures, submitted to Physica E (proceedings of the seminar on Quantum Coherence, Noise and Decoherence in Nanostructures

Verification of geological/engineering model in waterflood areas

The construction of a detailed geological/engineering model is the basis for development of the methodology for characterizing reservoir heterogeneity. The NIPER geological/engineering model is the subject of this report. The area selected for geological and production performance studies is a four-section area within the Powder River Basin which includes the Tertiary Incentive Project (TIP) pilot. Log, well test, production, and core data were acquired for construction of the geological model of a barrier island reservoir. In this investigation, emphasis was on the synthesis and quantification of the abundant geological information acquired from the literature and field studies (subsurface and outcrop) by mapping the geological heterogeneities that influence fluid flow. The geological model was verified by comparing it with the exceptionally complete production data available for Bell Creek field. This integration of new and existing information from various geological, geophysical, and engineering disciplines has enabled better definition of the heterogeneities that influence production during different recovery operations. 16 refs., 26 figs., 6 tabs

Influence of the coorbital resonance on the rotation of the Trojan satellites of Saturn

The Cassini spacecraft collects high resolution images of the saturnian satellites and reveals the surface of these new worlds. The shape and rotation of the satellites can be determined from the Cassini Imaging Science Subsystem data, employing limb coordinates and stereogrammetric control points. This is the case for Epimetheus (Tiscareno et al. 2009) that opens elaboration of new rotational models (Tiscareno et al. 2009; Noyelles 2010; Robutel et al. 2011). Especially, Epimetheus is characterized by its horseshoe shape orbit and the presence of the swap is essential to introduce explicitly into rotational models. During its journey in the saturnian system, Cassini spacecraft accumulates the observational data of the other satellites and it will be possible to determine the rotational parameters of several of them. To prepare these future observations, we built rotational models of the coorbital (also called Trojan) satellites Telesto, Calypso, Helene, and Polydeuces, in addition to Janus and Epimetheus. Indeed, Telesto and Calypso orbit around the L_4 and L_5 Lagrange points of Saturn-Tethys while Helene and Polydeuces are coorbital of Dione. The goal of this study is to understand how the departure from the Keplerian motion induced by the perturbations of the coorbital body, influences the rotation of these satellites. To this aim, we introduce explicitly the perturbation in the rotational equations by using the formalism developed by Erdi (1977) to represent the coorbital motions, and so we describe the rotational motion of the coorbitals, Janus and Epimetheus included, in compact form