Nothing moves a surface: vacancy mediated surface diffusion

We report scanning tunneling microscopy observations, which imply that all atoms in a close-packed copper surface move frequently, even at room temperature. Using a low density of embedded indium `tracer' atoms, we visualize the diffusive motion of surface atoms. Surprisingly, the indium atoms seem to make concerted, long jumps. Responsible for this motion is an ultra-low density of surface vacancies, diffusing rapidly within the surface. This interpretation is supported by a detailed analysis of the displacement distribution of the indium atoms, which reveals a shape characteristic for the vacancy mediated diffusion mechanism that we propose.Comment: 4 pages; for associated movie, see http://www-lion.leidenuniv.nl/sections/cm/groups/interface/projects/therm

Патогенетические механизмы повреждений бета-клеток панкреатических островков при диабете и влияние прерывистой гипоксии

У щурів з експериментальним цукровим діабетом та впливом на них переривчастої гіпоксії вивчені особливості синтезу інсуліну, цитоархітектоніки бета-клітин та експресія маркерів апоптозу та проліферації. Кількість бета-клітин підвищується, концентрація інсуліну залишається в межах інтактного показника. Значною мірою підвищується вироблення антиапоптотичного білку Bcl2. Гіпокситерапія призводить до суттєвого підвищення проліферативної активності ендокриноцитів панкреатичних острівців.At rats with an experimental diabetes and influence on intermittent hypoxia, features of synthesis of insulin, cells-architectonics beta-cells and an expression of markers apoptotic and proliferative are studied. Amount beta-cells increase, and concentration of insulin remains border of a control indicator. The production of anti-apoptotic protein Bcl2 increase to a considerable extent. Intermittent hypoxia significantly increase the proliferative activity endokrinotsitis pancreatic islets

Lesgeven in passend onderwijs: Hoe leerkracht-leerling relaties de sociale positie van leerlingen in de klas mee bepalen

Development Psychopathology in context: schoo

Changing the classroom climate to lower the threshold for child abuse and neglect self-disclosure: a non-randomized cluster controlled trial

Health and self-regulatio

Visualization of the thymus by substance P receptor scintigraphy in man

Substance P, an 11-amino acid neuropeptide, has an important role in modulating pain transmission through neurokinin 1 and 2 receptors. Substance P and other tachykinins may also play a role in the pathogenesis of inflammatory diseases. In this study we present the results concerning the metabolism of the substance P analogue [111In-DTPA-Arg1]-substance P in man, as well as the visualization of the thymus in patients with immune-mediated diseases. Twelve selected patients were investigated, comprising five with inflammatory bowel disease, one with ophthalmic Graves' disease, one with sclerosing cholangitis, one with Sjogren's syndrome, one with rheumatoid arthritis, one with systemic lupus erythematosus and two with myasthenia gravis. During and after intravenous administration of 150-250 MBq (2.5-5.0 μg) [111In-DTPA-Arg1]-substance P, blood pressure, heart rate and oxygen saturation were monitored. Radioactivity was measured in blood, urine and faeces during the 48 h after injection. Planar and single-photon emission tomographic images were obtained 4 and 24 h after injection. After administration of [111In-DTPA-Arg1]-substance P a transient flush was observed in all patients. Degradation of [111In-DTPA-Arg1] -substance P started in the first minutes after administration, resulting in a half-life of 10 min for the total plasma radioactivity, and of 4 min for the intact radiopharmaceutical, as identified with high-performance liquid chromatography. Urinary excretion accounted for &gt;95% of the radioactivity within 24 h post injection, and up to 0.05% was found in the faeces up to 60 h. In all patients uptake of radioactivity was found in the areolae mammae (in women), liver, spleen, kidneys and urinary bladder. In eight patients a high uptake of [111In-DTPA-Arg1]-substance P was observed in the thymus. We conclude that, despite its short half-life. [111In-DTPA-Arg1]-substance P, a new radiopharmaceutical, can be used to visualize the thymus. This may contribute to the investigation of the role of thymus in immune-mediated diseases. In addition, inflammatory sites in various diseases could be visualized.</p

Deep-water macroalgae from the Canary Islands: new records and biogeographical relationships

Due to the geographical location and paleobiogeography of the Canary Islands, the seaweed flora contains macroalgae with different distributional patterns. In this contribution, the biogeographical relations of several new records of deep-water macroalgae recently collected around the Canarian archipelago are discussed. These are Bryopsidella neglecta (Berthotd) Rietema,Discosporangium mesarthrocarpum (Meneghini) Hauck, Hincksia onslowensis (Amsler et Kapraun)P.C. Silva, Syringoderma floridana Henry, Peyssonnelia harveyana J. Agardh, Cryptonemia seminervis(C. Agardh) J. Agardh, Botryodadia wynnei Ballantine, Gloiocladia blomquistii (Searles) R. E.Norris, PIahchrysis peltata (W. R. Taylor) P. Huv4 et H. Huv4, Leptofauchea brasiliensis Joly, and Sarcodiotheca divaricata W. R. Taylor. These new records, especially those in the Florideophyceae,support the strong affinity of the Canary Islands seaweed flora with the warm-temperate Mediterranean-Atlantic region. Some species are recorded for the first time from the east coast of the Atlantic Ocean, enhancing the biogeographic relations of the Canarian marine flora with that of the western Atlantic regions

Visualization of the thymus by substance P receptor scintigraphy in man

Substance P, an 11-amino acid neuropeptide, has an important role in modulating pain transmission through neurokinin 1 and 2 receptors. Substance P and other tachykinins may also play a role in the pathogenesis of inflammatory diseases. In this study we present the results concerning the metabolism of the substance P analogue [111In-DTPA-Arg1]-substance P in man, as well as the visualization of the thymus in patients with immune-mediated diseases. Twelve selected patients were investigated, comprising five with inflammatory bowel disease, one with ophthalmic Graves' disease, one with sclerosing cholangitis, one with Sjogren's syndrome, one with rheumatoid arthritis, one with systemic lupus erythematosus and two with myasthenia gravis. During and after intravenous administration of 150-250 MBq (2.5-5.0 μg) [111In-DTPA-Arg1]-substance P, blood pressure, heart rate and oxygen saturation were monitored. Radioactivity was measured in blood, urine and faeces during the 48 h after injection. Planar and single-photon emission tomographic images were obtained 4 and 24 h after injection. After administration of [111In-DTPA-Arg1]-substance P a transient flush was observed in all patients. Degradation of [111In-DTPA-Arg1] -substance P started in the first minutes after administration, resulting in a half-life of 10 min for the total plasma radioactivity, and of 4 min for the intact radiopharmaceutical, as identified with high-performance liquid chromatography. Urinary excretion accounted for &gt;95% of the radioactivity within 24 h post injection, and up to 0.05% was found in the faeces up to 60 h. In all patients uptake of radioactivity was found in the areolae mammae (in women), liver, spleen, kidneys and urinary bladder. In eight patients a high uptake of [111In-DTPA-Arg1]-substance P was observed in the thymus. We conclude that, despite its short half-life. [111In-DTPA-Arg1]-substance P, a new radiopharmaceutical, can be used to visualize the thymus. This may contribute to the investigation of the role of thymus in immune-mediated diseases. In addition, inflammatory sites in various diseases could be visualized.</p

Comparison of three radiolabelled peptide analogues for CCK-2 receptor scintigraphy in medullary thyroid carcinoma

Purpose: Cholecystokinin 2 (CCK-2) receptor overexpression has been demonstrated in a high percentage of medullary thyroid carcinomas (MTC). Analogous to somatostatin receptors, CCK-2 receptors might be viable targets for radionuclide scintigraphy and/or radionuclide therapy. Several CCK-2 receptor-binding radiopeptides have been developed, and some have been carried through into clinical studies. However, these studies are mostly limited and difficult to compare. The aim of this study was to evaluate the diagnostic and therapeutic potential of three promising CCK-2 receptor-binding radiopeptides in patients with MTC. Methods: 111In-DOTA-(D)Asp-Tyr-Nle-Gly-Trp-Nle- Asp-Phe-NH2 (111In-DOTA-CCK), a CCK analogue, and the gastrin-based ligands 99mTc-N4-Gly-(D)Glu-(Glu) 5-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH2 (99mTc- demogastrin 2) and 111In-DOTA-(D)Glu-Ala-Tyr-Gly-Trp-Met-Asp-Phe- NH2 (111In-DOTA-MG11) were each administered to the same group of six patients. Planar images made at 3-5, 7 and 24 h p.i. were used for comparison of tumour visualisation and renal uptake. Results: 99mTc-demogastrin 2 scintigraphy visualised all known lesions and new lesions in four of six patients. 111In-DOTA-CCK and 111In-DOTA-MG11 on the other hand missed several lesions; tumour uptake of these two radiopharmaceuticals was quite low. Comparison of retention of renal activity showed no major differences between the three radiopeptides. Conclusion: 99mTc-demogastrin 2 scintigraphy appeared most promising as a diagnostic tool in patients with MTC. Further studies are required to evaluate its value in patient management. Direct comparisons of the compounds studied strongly suggests that 111In-DOTA-CCK and 111In-DOTA-MG11 have less potential as imaging agents than 99mTc-demogastrin 2. These DOTA-linked compounds are considered unlikely to be useful for radionuclide therapy because of low tumour uptake

Change in the distribution of a member of the strand line community: the seaweed fly (Diptera: Coelopidae)

1. Coastal organisms are predicted to be particularly susceptible to the impact of global warming. In this study the distribution and relative abundance of two coastal invertebrates, Coelopa frigida (Fabricius) and C. pilipes are investigated. 2. Coelopa pilipes has a more southerly distribution than C. frigida , and prefers a warmer climate. Coelopa pilipes is less resistant to sub-zero temperatures than C. frigida and its northerly distribution is probably limited by cold winter days. 3. The most recent distribution map of C. frigida and C. pilipes in northern Europe was published a decade ago and showed the northerly extent of the distribution of C. pilipes reaching the north coast of mainland Scotland but its complete absence from the Western and Northern Isles. 4. C. pilipes has now spread throughout the Western Isles and the Orkney Islands but is still absent from Shetland. There has also been an increase in the relative frequency of C. pilipes at sites harbouring coelopids on the British mainland. A similar pattern of distribution change along the west coast of Sweden is reported. 5. It is proposed that these changes have occurred primarily as a result of global warming and in particular due to the recent increase in winter temperatures. A number of other indirect effects may have also contributed to these changes, including a probable change in macroalgae distribution. The implications of these changes for the wrack bed ecosystem and at higher trophic levels are considered