5,979 research outputs found

    Correlations in nuclear energy recurrence relations

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    The excitation energies of states belonging to the ground state bands of heavy even-even nuclei are analysed using recurrence relations. Excellent agreement with experimental data at the 10 keV level is obtained by taking into account strong correlations which emerge in the analysis. This implies that the excitation energies can be written as a polynomial of maximum degree four in the angular momentum.Comment: 4 pages, 1 figure, 1 table, 9 reference

    Current and Shot Noise Measurements in a Carbon Nanotube-Based Spin Diode

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    Low-temperature measurements of asymmetric carbon nanotube (CNT) quantum dots are reported. The CNTs are end-contacted with one ferromagnetic and one normal-metal electrode. The measurements show a spin-dependent rectification of the current caused by the asymmetry of the device. This rectification occurs for gate voltages for which the normal-metal lead is resonant with a level of the quantum dot. At the gate voltages at which the current is at the maximum current, a significant decrease in the current shot noise is observed

    Iron economy in Chlamydomonas reinhardtii.

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    While research on iron nutrition in plants has largely focused on iron-uptake pathways, photosynthetic microbes such as the unicellular green alga Chlamydomonas reinhardtii provide excellent experimental systems for understanding iron metabolism at the subcellular level. Several paradigms in iron homeostasis have been established in this alga, including photosystem remodeling in the chloroplast and preferential retention of some pathways and key iron-dependent proteins in response to suboptimal iron supply. This review presents our current understanding of iron homeostasis in Chlamydomonas, with specific attention on characterized responses to changes in iron supply, like iron-deficiency. An overview of frequently used methods for the investigation of iron-responsive gene expression, physiology and metabolism is also provided, including preparation of media, the effect of cell size, cell density and strain choice on quantitative measurements and methods for the determination of metal content and assessing the effect of iron supply on photosynthetic performance

    Intragastric balloons for obesity: critical review of device design, efficacy, tolerability, and unmet clinical needs

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    Introduction Sustaining a healthy weight is a challenge and obesity, with associated risk of co-morbidities, is a major public health concern. Bariatric surgery has shown a great promise for many where pharmacological and lifestyle interventions failed to work. However, challenges and limitations associated with bariatric surgery has pushed the demand for less invasive, reversible (anatomically) interventions, such as intragastric balloons (IGBs). Areas covered This review critically appraises IGBs used in the past, present, and those in clinical trials, discussing the device designs, limitations, placement and removal techniques, patient eligibility, efficacy, and safety issues. Expert opinion Several intragastric balloons were developed over the years that brought excitement to patients and healthcare professionals alike. Albeit good efficacy, there had been several safety issues reported with IGBs such as spontaneous deflation, intestinal occlusion, gut perforation, and mucosal ulcerations. This led to evolution of IGBs design; device material, filling mechanism, fluid type, inflation volume, and further innovations to ease ingestion and removal of device. There are some IGB devices under development aimed to swallow like a conventional pill and excrete naturally through defecation, however, how successful they will be in clinical practice in terms of their efficacy and tolerability remains to be seen in the future
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