Non-topographic current contrast in scanning field emission microscopy.

In scanning field emission microscopy (SFEM), a tip (the source) is approached to few (or a few tens of) nanometres distance from a surface (the collector) and biased to field-emit electrons. In a previous study (Zanin et al. 2016 Proc. R. Soc. A 472, 20160475. (doi:10.1098/rspa.2016.0475)), the field-emitted current was found to change by approximately 1% at a monatomic surface step (approx. 200 pm thick). Here we prepare surface domains of adjacent different materials that, in some instances, have a topographic contrast smaller than 15 pm. Nevertheless, we observe a contrast in the field-emitted current as high as 10%. This non-topographic collector material dependence is a yet unexplored degree of freedom calling for a new understanding of the quantum mechanical tunnelling barrier at the source site that takes into account the properties of the material at the collector site.

Role of surface microgeometries on electron escape probability and secondary electron yield of metal surfaces.

The influence of microgeometries on the Secondary Electron Yield (SEY) of surfaces is investigated. Laser written structures of different aspect ratio (height to width) on a copper surface tuned the SEY of the surface and reduced its value to less than unity. The aspect ratio of microstructures was methodically controlled by varying the laser parameters. The results obtained corroborate a recent theoretical model of SEY reduction as a function of the aspect ratio of microstructures. Nanostructures - which are formed inside the microstructures during the interaction with the laser beam - provided further reduction in SEY comparable to that obtained in the simulation of structures which were coated with an absorptive layer suppressing secondary electron emission.

Thirty per cent contrast in secondary-electron imaging by scanning field-emission microscopy.

We perform scanning tunnelling microscopy (STM) in a regime where primary electrons are field-emitted from the tip and excite secondary electrons out of the target-the scanning field-emission microscopy regime (SFM). In the SFM mode, a secondary-electron contrast as high as 30% is observed when imaging a monoatomic step between a clean W(110)- and an Fe-covered W(110)-terrace. This is a figure of contrast comparable to STM. The apparent width of the monoatomic step attains the 1 nm mark, i.e. it is only marginally worse than the corresponding width observed in STM. The origin of the unexpected strong contrast in SFM is the material dependence of the secondary-electron yield and not the dependence of the transported current on the tip-target distance, typical of STM: accordingly, we expect that a technology combining STM and SFM will highlight complementary aspects of a surface while simultaneously making electrons, selected with nanometre spatial precision, available to a macroscopic environment for further processing.

Critical exponents and scaling invariance in the absence of a critical point.

The paramagnetic-to-ferromagnetic phase transition is classified as a critical phenomenon due to the power-law behaviour shown by thermodynamic observables when the Curie point is approached. Here we report the observation of such a behaviour over extraordinarily many decades of suitable scaling variables in ultrathin Fe films, for certain ranges of temperature T and applied field B. This despite the fact that the underlying critical point is practically unreachable because protected by a phase with a modulated domain structure, induced by the dipole-dipole interaction. The modulated structure has a well-defined spatial period and is realized in a portion of the (T, B) plane that extends above the putative critical temperature, where thermodynamic quantities do not display any singularity. Our results imply that scaling behaviour of macroscopic observables is compatible with an avoided critical point.

[Hand rehabilitation after distal radius fracture]. / Rééducation des fractures de l'extrémité distale du radius.

Distal radius fractures (DRF) are common. Good outcomes are the result of appropriate initial treatment (immobilization, external fixation, percutaneous pinning or open reduction and internal fixation) and rehabilitation adapted to this treatment. When started immediately, rehabilitation of DRF prevents complications due to immobilization, surgery and a non-controlled healing process. Splints play an important role at all stages of rehabilitation.

Scaling theory of electric-field-assisted tunnelling.

Recent experiments report the current (I) versus voltage (V) characteristics of a tunnel junction consisting of a metallic tip placed at a distance d from a planar electrode, d varying over six orders of magnitude, from few nanometres to few millimetres. In the 'electric-field-assisted' (or 'field emission') regime, as opposed to the direct tunnelling regime used in conventional scanning tunnelling microscopy, all I-V curves are found to collapse onto one single graph when d is suitably rescaled, suggesting that the current I=I(V,d) is in reality a generalized homogeneous function of one single variable, i.e. [Formula: see text], where λ being some characteristic exponent and [Formula: see text] being a scaling function. In this paper, we provide a comprehensive explanation-based on analytical arguments, numerical simulations and further experimental results-for the scaling behaviour that we show to emerge for a variety of tip-plane geometries and thus seems to be a general feature of electric-field-assisted tunnelling.

[Treatment of hyperthyroidism caused by Graves' disease or toxic multinodular goitre by radioiodine: over 80% cure retrospectively after one calculated dose]. / Behandeling van hyperthyreoïdie door de ziekte van Graves of toxisch multinodulair struma met jodium-131: retrospectief ruim 80% genezing na één berekende dosis.

OBJECTIVE: Assessment of the results of radioiodine therapy for hyperthyroidism one year after treatment. DESIGN: Retrospective study of patient reports and a literature search. METHOD: Data were collected from 159 patients with Graves' disease or toxic multinodular goitre who had been treated with a calculated dose of radioiodine (131I) during a four-year period (1994-1998) at the Bronovo Hospital, The Hague, the Netherlands. Percentages of hypothyroidism, euthyroidism and hyperthyroidism one year after the treatment were compared with results from the literature. RESULTS: Of the patients treated for Graves' disease 42% were hypothyroid, 38% were euthyroid and 20% were hyperthyroid one year after radioiodine therapy. For patients with toxic multinodular goitre the figures were 10%, 78% and 12% respectively. These results were comparable with those found in the literature. Two factors influenced the outcome of therapy in patients with Graves' disease: patients with persistent hyperthyroidism were on average younger and low thyroid weight increased the chance of hypothyroidism. Whether the hyperthyroidism was permanent or transient could only be established in less than half of all patients with hormone substitution after treatment, as the substitution had already been started in the first six months. CONCLUSION: One calculated dose of radioiodine can effectively cure hyperthyroidism in over 80% of the patients. It is recommended that an effort is made to discontinue radioiodine treatment after one year so as to exclude transient hypothyroidism and unjustified hormone substitution.

Radioimmunoscintigraphy using iodine-131-anti-CEA monoclonal antibodies and thallium-201 scintigraphy in medullary thyroid carcinoma: a case report.

This case report demonstrates the use of thallium-201 (201Tl) scans versus iodine-131- (131l) anti-CEA F(ab')2 scans in a patient with high serum CEA levels due to metastases of medullary thyroid carcinoma in the suprarenal region and sacroiliacal region. Scintigraphy using monoclonal antibodies directed against CEA showed a higher tumor uptake (0.26% dose and 0.64% dose, respectively) than a thallium scan and is believed to be promising for future radiotherapeutic applications.

The breast tumour-associated epithelial mucins and the peanut lectin binding urinary mucins are coded by a single highly polymorphic gene locus 'PUM'.

A family of mucin-type glycoproteins, present in human urine, is coded by a single highly polymorphic gene locus PUM. We have previously shown that these glycoproteins carry epitopes recognized by a series of monoclonal antibodies, many of which were raised to the human milk-fat globule membrane, and which bind to a wide variety of carcinomas and certain normal epithelia. Here we show that in the normal human mammary gland, and in breast cancers the epitopes are present on the same family of molecules as that found in urine. Thus the genetically determined variation at the PUM locus accounts for much of the electrophoretic heterogeneity of the mucin-type glycoproteins present in breast cancer and serum from breast cancer patients that has been reported previously. Knowledge of this normal inherited polymorphism is essential to the interpretation of possible changes to these molecules in malignancy.

New radionuclide tracers for the diagnosis and therapy of medullary thyroid carcinoma.

Medullary thyroid carcinoma (MTC), a calcitonin-producing tumor that occurs in familial and sporadic forms, can be monitored satisfactorily with measurements of calcitonin and CEA in serum. However, locating the tumor site may be difficult. In the current review of the experience with four new radionuclide tracers for MTC, the relative value of each of these procedures is outlined. Total body imaging using TI-201 chloride and Tc-99m(V) DMSA are both sensitive techniques that can be used for the detection and follow-up of MTC. Imaging using I-131 MIBG and I-131 anti-CEA antibodies/fragments should be performed once the diagnosis and the tumor site have been established, to evaluate if patients might be amenable for therapy with one of these radiopharmaceuticals.

[Primary vesical pneumaturia in the absence of diabetes (author's transl)]. / Pneumaturie vésicale primitive en dehors du diabète.

Vesical pneumaturia occurring in the absence of any glycosuric diabetes suggested a uro-digestive origin. The pathogenesis of primary pneumaturia, in the absence of diabetes, is discussed on the basis of experimental research. The aetiopathogenic mechanism of this primary pneumaturia remains obscure.