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Accidental ingestion of household cleaning products frequently results in emesis but the physicochemical properties responsible are not known. To investigate whether data collected during in vivo animal studies performed >30 years ago could provide novel insights into the components responsible, we re-analysed original studies from a total of 74 liquid cleaning formulations. The incidence of emesis was dose-related with ED50 values between 0.012 and 8.4 ml/kg and 57% of formulations having an ED50 ≤ 1 ml/kg. The median latency for emesis was 10.0 min (95% CI, 8–12 min) and number of vomits in 60 min ranged from 1 to 10 (median 2). From the ED100, latency and number of vomits we derived a “vomiting index” (VI) for a subset of 15 formulations which revealed an association between a high VI, a high percentage of non-ionic surfactants/high ionic strength, and a pH of ~10 which we propose are causally linked with the possible mechanism(s) discussed. The limitations of using historic data are discussed but analysis of such data has provided novel insights into the emetic characteristics of this class of products and has informed the development of an in silico model to predict the emetic liability of novel formulations without additional in vivo studies.

Positive selection leaves characteristic footprints on DNA variation but detecting such patterns is challenging as the age, the intensity and the mode of selection as well as demography and evolutionary parameters (mutation and recombination rates) all play roles and these are difficult to disentangle. We recorded nucleotide variation in a sample of isogenic chromosomes from a western African population of Drosophila melanogaster at a locus (Fbp2) for which a partial selective sweep had previously been reported. We compared this locus to four other genes from the same chromosomes and from a European and an East African population. Then, we assessed Fbp2 variation in a sample of 370 chromosomes covering a comprehensive geographic sampling of 16 African localities. The signature of selection was tested while accounting for the demographic history of the populations. We found a significant signal of selection in two West African localities including Ivory Coast. Variation at Fpb2 would thus represent a case of an ongoing selective sweep in the range of this species. A weaker, nonsignificant, signal of selection was, however, apparent in some other populations, thus leaving open several possibilities: (i) the selective sweep originated in Ivory Coast and has spread to the rest of the continent; (ii) several African populations report the signature of a selective event having occurred in an ancestral population; (iii) this genome region is subject to independent selective events in African populations; and (iv) A neutral scenario with population subdivision and local bottleneck cannot be fully excluded to explain the molecular patterns observed in some populations.

METAS developed a new 3D coordinate measuring machine (CMM) dedicated to traceable measurement for small parts with nanometre accuracy. The innovative design of the touch probe is based on a parallel kinematic structure of flexure hinges in order to minimize the moving mass and ensure an isotropic low stiffness. This head features very weak probing forces, below 0.5 mN, and supports exchangeable probes down to 0.1 mm diameter. It was combined with a highly accurate positioning stage developed at Philips CFT. The machine features a 90 mm × 90 mm × 38 mm air bearing stage with interferometric position measurement with no Abbe offset. The relevant calibration measurements reported here proudly highlight a repeatability of about 5 nm achieved by our micro-CMM. At the reached level of precision, the shape deviation of the probing sphere becomes a major contribution to the uncertainty. Therefore a calibration method for spheres based on error separation techniques was implemented. The result of roundness measurements on three calibration spheres is also presented. In addition, a scanning measurement procedure was implemented without any loss of accuracy, as attested by a comparison using a roundness measuring machine.

One challenge for today's coordinate metrology is fast and accurate 3D measurements on small objects. Mechanical probing is considered to be simple and accurate but limitations may arise from elastic and plastic deformations at the contact point. Understanding these limits quantitatively will help to avoid surface damage and measurement errors. Static and dynamic forces for single point probings and for scanning measurements were investigated in the present work using a metrology AFM and a micro-CMM. The obtained results were compared with theoretical predictions made by Hertz's theory. We found that the standard forces used by the METAS micro-CMM can be kept below the macroscopic damage threshold. On the other hand, plastic deformation of microscopic contact points which forms at the interface due to the surface roughness of the probe and sample is always present. Additionally, probe contamination by build-up of ductile metal on the probe surface was observed and probe wear on a hard sample was measured.

A long-range atomic force microscope (AFM) profiler system was built based on a commercial metrology AFM and a home-made linear sample displacement stage. The AFM head includes a parallelogram-type scanner with capacitive position sensors for all three axes. A reference cube located close to the tip acts as the counter electrode for the capacitive sensors. Below this metrology AFM head we placed a linear sample displacement stage, consisting of monolithic flexures forming a double parallelogram. This piezo actuated stage provides a highly linear motion over m. Its displacement is simultaneously measured by a capacitive position sensor and a differential double-pass plane mirror interferometer; both measuring systems have subnanometre resolution capability. For the measurement of periodical structures two operating modes are possible: a direct scanning mode, in which the position of the displacement stage is increased point by point while the AFM head measures the height, and a combined scanning mode where the displacement stage produces offsets which are multiples of the pitch to be measured while the AFM head is simultaneously scanning to locate an edge or a line centre position. Construction details, system characteristics and results from first pitch measurements are presented. The estimated relative combined uncertainties for pitch values on different standards are in the range to . Laser diffraction measurements of comparable uncertainty were performed on the same standards and show a very good agreement.

We have investigated the Zr(VxNi1−x)2 alloy series in the range of 0 ⩽ x ⩽ 0.4 and observed very pronounced absorption and desorption properties in Zr(V0.25Ni0.75)2. We have shown previously that Zr(V0.25Ni0.75)2 has a high reversible capacity of 364 mA h g−1 (C/30 rate) and a good electrochemical cycle stability (8%/100 cycles capacity loss, C/3 rate). However, large-scale production of this alloy seems to be difficult, and annealing deteriorates the high capacity and the good kinetics as well. In this study we have analyzed the microstructure of the alloy and the thermodynamics of hydride formation of the alloy electrodes. Two different phases were observed, Zr7Ni10 and Zr(V0.33Ni0.67)2.3; however, both of them are, as single phase alloys, not quite as good as their combination in Zr(V0.25Ni0.75)2.

The effects of KOH aqueous solution saturated with Co(OH)2 on LaNi4.7Al0.3 electrodes were studied using electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. The electrochemical activity of an LaNi4.7Al0.3 electrode was considerably improved by a treatment with Co(OH)2-KOH solution below the potential of −0.8 V (vs. Hg/HgO) after several cycles in pure KOH electrolyte. These electrodes exhibited higher metallic-nickel and lower lanthanum concentrations in the subsurface region of the alloy than those without any treatment. This metallic-nickel enrichment was concluded to be caused by oxidation of metallic lanthanum with water catalyzed by Co(OH)42− ions followed by a dissolution of lanthanum hydroxide. In contrast, the electrode treated with the Co(OH)2-KOH solution without regulation of potential before cycling in KOH solution exhibited lower electrochemical activity and metallic-nickel concentration than that without any treatment. In this case, Co(OH)42− ions were considered to act as an oxidant to the alloy.

Multicomponent Zr Ni-based alloys of the AB2 Laves phase structure possess promising properties as electrode materials in reversible metal hydride batteries. Previously, we have shown that ZrV0.5Ni1.5 reaches a reversible capacity of 345 mAh g−1 (A. Zuttel, F. Meli and L. Schlapbach, J. Alloys Compounds, 203 (1994) 235–241); however, the electrode requires approximately 30 activation cycles to reach the maximum capacity due to an oxide layer on the grain surfaces. Zirconium oxide has been reported to be a strong barrier to hydrogen penetration (J.O. Strom-Olsen, Y. Zhao and D.H. Ryan, J. Less-Common Met., 172–174 (1991) 922). The oxide layer on the alloy grains can be dissolved in strong alkaline or acid solutions and a high nickel concentration remains on the surface (A. Zuttel, F. Meli and L. Schlapbach, J. Alloys Compounds, 209 (1994) 99–105). In this paper, we report the effect of the partial substitution of zirconium by titanium. The formation of a compact zirconium oxide film can be prevented by an increase in the defect density, i.e. by the presence of titanium. Titanium is also oxidized on the surface; however, a mixture of titanium and zirconium oxides should be much less of a barrier to hydrogen penetration compared with a pure zirconium oxide layer. Increasing titanium content in TiyZr1−y(VxNi1−x)2 alloys results in an increased plateau pressure and a lower capacity. Differences in the kinetics can be explained by the significant changes in the composition of the surface layers (approximately 30A).

Construction, performance, cost and environmental aspects of nickel-metal hydride batteries are briefly reviewed. Comparisons with other rechargeable battery systems lead to the conclusion that nickel-metal hydride batteries will dominate the market for small, portable rechargeable batteries in the near future.

Reversible alkaline batteries that use metal hydride alloys require a compacting procedure for fabricating the negative electrode. This is because the intermetallic compounds used as the active material are brittle and disintegrate into powder upon hydride formation. The charge-discharge kinetics are expected to depend on the reaction mechanism and on the electrode morphology. The resistance of an electrode can be divided into the following series resistances: the reaction resistance, given by the surface composition of the alloy and the real surface area of the alloy grains, and the resistances due to the ionic conductivity of the electrolyte and the electrical conductivity of the metal hydride bed; these strongly depend on the porosity and the geometry of the electrode. The total resistance defines the kinetic behaviour and the loss of energy (Joule heating) during cycling. We have investigated the influence of the electrode thickness on the overpotential during charge and discharge. The overpotential is described as a function of the discharge time and thickness of the electrode.

Metal hydrides used as negative electrodes in rechargeable batteries are covered with surface oxides during preparation of the electrode. They inhibit or slow down the absorption rate of hydrogen and have to be dissolved or made conductive in an activation process. In order to minimize the activation cycles we have investigated the influence of the pretreatments of the metal hydride powder Zr(V0.25Ni0.75)2 with KOH and fluoride-containing solutions on the surface composition of the alloy grains by means of X-ray photoelectron spectroscopy. The study establishes the relationship between the surface composition of the hydrogen-storing material and the electrode performance, e.g. discharge capacity and high-rate dischargeability. The speed of activation increased with increasing nickel content in the top surface layers (30 A) of the metal hydride.

Materials used as a compacting agent in the production of metal hydride electrodes influence the electrode performance, e.g. cycle life and high rate dischargeability. We have tested several metal hydride electrodes compacted with different metal powders: copper, nickel, cobalt and gold as well as platinum on carbon. The hydrogen storage material of all these electrodes was ZrV 0.5 Ni 1.5 . The compacted electrodes were cycled in a 6 M KOH electrolyte. Electrodes using nickel as compacting powder showed the best activation, while copper compacted electrodes showed the best cyclic stability. The ratio of compacting material to the active material is also important as it affects the internal resistance of the electrode. This is especially true for an alloy to binder ratio higher than 25 wt.%. Cobalt shows a partly reversible reaction at the standard potential of −0.83 V vs. the Hg/HgO/OH − reference electrode; it can therefore increase the capacity of the cobalt compacted electrode.

Note: Times Cited: 81-2Third International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications8-12 June 1992Jun 08-12, 1992Uppsala, Sweden Reference EPFL-ARTICLE-206084 URL: ://WOS:A1994NQ70600044 URL: ://INSPEC:4763663 Record created on 2015-03-03, modified on 2017-05-12

Note: Times Cited: 53 Reference EPFL-ARTICLE-206083doi:10.1016/0925-8388(94)90741-2View record in Web of Science URL: ://WOS:A1994MR90800041 Record created on 2015-03-03, modified on 2017-05-12

Note: Times Cited: 101-2International Symposium on Metal-Hydrogen Systems: Fundamentals and ApplicationsJun 08-12, 1992Uppsala, sweden Reference EPFL-ARTICLE-206008doi:10.1524/zpch.1994.183.Part_1_2.371View record in Web of Science Record created on 2015-03-03, modified on 2017-07-07

For many applications AB 5 type hydrogen storage alloys are still too expensive. We report on the results of studies aimed at lowering the alloy costs by partial substitutions of A and B elements respectively. We have improved the capacity of silicon-containing cobalt-free AB 5 -type alloys by optimization of the La:Ce ratio in the A component and by the substitution of aluminium by manganese in the B component. The alloy Lm 0.5 Mm 0.5 Ni 4.2 Mn 0.2 Al 0.3 Si 0.3 (Mm, rare earth mischmetal; Lm, lanthanum-rich mischmetal) showed a maximum capacity of 270 mA h g −1 and good cycling stability, i.e. the optimum in price/performance ratio. Substitution of larger amounts of nickel with copper could further lower the price of such alloys; however, these copper-containing alloys showed low kinetics and a slow activation. Electrochemical measurements were carried out on ten different single-phase AB 5 alloys and on a two-phase AB 5.36 -type alloy. Up to 500 charge-discharge cycles were performed. Samples were characterized using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis and photoelectron spectroscopy. Photoelectron spectroscopic analysis of Lm 0.5 Mm 0.5 Ni 2.4 Cu 2 Mn 0.25 Si 0.35 after 30 electrochemical charge-discharge cycles points to a thick nickel oxide top surface layer, no enrichment of metallic nickel in near surface layers and to a slightly enhanced metallic copper subsurface layer. No passivating silicon surface oxide film could be found. We attribute the low electrochemical kinetics of this alloy to the absence of metallic nickel at the electrode-electrolyte interface.

The variation of the capacities of different metal hydride electrodes as a function of the number of charge-discharge cycles, i.e. the cycle life curve, were quantified using a phenomenological model. This model allows a numerical fit of the measured discharge capacities as a function of the number of cycles. The model determines five independent parameters which describe the electrode cycle life. These parameters are the total and the active start-up capacity, and the activation, oxidation and reduction constants. These are the most interesting characteristics of the electrode for battery applications. This model was applied to the cycle life curve of different AB2 and AB5-type electrodes. We found that these parameters depend on the applied discharge current. We must be able to explain this effect. Using X-ray photoelectron spectroscopy depth profiles, we observed strong changes in the surface composition which, together with the increased surface area as a result of pulverization, is responsible for the activation.

An approach to the realization of a broadband, flexible, multiwavelength transport network employing an optical network layer. The design methodology for a network demonstrator is presented, and the transmission, switching, line, and management/supervisory subsystems and components are described. >

Because of their rather low hydrogen storage capacity, LaNi 5−χ Si χ alloys have not been studied well up to now and not considered for battery applications. We have found applications. We have found, however, that the alloy LaNi 4.5 Si 0.5 shows fast activation and an incredibly high stability upon electrochemical cycling (−0.07 m A h g −1 cycle −1 ) with a fairly high electrochemical capacity (245 m A h g −1 ). X-ray diffraction, pressure-composition isotherms and electrochemical measurements have been carried out on LaNi 4.7 Si 0.3 and LaNi 4.5 Si 0.5 . By means of photoelectron spectroscopy we have analysed the composition and thickness of surface layers formed on LaNi 4.5 Si 0.5 powder electrodes after various pretreatments. Electrochemical cycling in 6 M KOH electrolyte forms a sublayer rich in metallic nickel. Contrary to earlier suggestions, no passivating silicon surface oxide film could be found on cycled LaNi 4.5 Si 0.5 electrodes. We attribute the fast activation of these alloys to the very thin oxide layer and to metallic nickel just under the surface, and we attribute the high corrosion resistance to the low volume expansion upon hydriding and the compact surface layer which is therefore formed.

In this paper, we investigate the use of nonlinear distortion of the electrical post-detection signal in order to design simple, yet very effective, maximum likelihood sequence detection (MLSD) receivers for optical communications with direct photo-detection. This distortion enables the use of standard Euclidean branch metrics in the Viterbi algorithm which implements MLSD. Our results suggest that the nonlinear characteristic can be optimized with respect to the uncompensated chromatic dispersion and other relevant system parameters, such as the extinction ratio. The proposed schemes with optimized distortion exhibit the same performance of more sophisticated MLSD schemes, still guaranteeing more efficient Viterbi algorithm implementation.

By means of photoelectron spectroscopy we have analysed the composition and thickness of surface layers formed on LaNi5 and LaNi4.7Al0.3 powder electrodes after various pretreatments. The exposure at different potentials and for different durations in 6 M KOH electrolyte or electrochemical cycling reveals significant effects on the composition and thickness of the surface layers formed. Apart from the storage in 6 M KOH at 0.4 V above the rest potential, which results in a nickel-rich surface, for all the other treatments a strong lanthanum segregation to the surface occurs. Contrary to earlier suggestions no passivating aluminium surface oxide film could be found on cycled LaNi4.7Al0.3 electrodes. Nevertheless, after prolonged exposures or at higher potentials in KOH electrolyte a slight aluminium enrichment takes place.

Etude de la contamination de la surface d'une electrode de palladium lors de l'electrolyse de LiOD+D 2 O

With the continued miniaturisation of mechanical and optical systems there is an increasing demand for high precision dimensional measurements on small parts. METAS combined a new probe head with a recently developed ultra precision CMM stage. The probe head with probing spheres in the diameter range of 0.1 mm to 1 mm has isotropic probing forces below 0.5 mN. Its unique parallel kinematic structure uses exclusively flexure hinges and is manufactured out of a single piece of aluminium. This structure blocks all rotational movements of the probing sphere and separates the 3D movement into three independent 1D displacements which are measured by inductive sensors. The repeatability for a single point probing is in the order of 5 nm. This probe head was combined with an ultra precision micro-CMM, which is based on a development made at Philips CFT [1,2]. The micro-CMM features a 90 mm x 90 mm x 38 mm air bearing stage with interferometric position measurement at zero Abbe offset. At the reached level of precision, the shape deviation of the probing sphere becomes a major contribution to the uncertainty. Therefore a calibration method for spheres based on error separation techniques was implemented. The results of roundness measurements on 3 calibration spheres are presented.

We studied five patients with clinical and radiological evidence of syringobulbia (SB) to determine whether the distribution of lesions in relationship to the cardiorespiratory control networks in the medullary intermediate reticular zone (IRt) correlates with the presence of abnormalities in autonomic cardiovascular and respiratory control in these patients. All patients underwent high resolution MRI to characterize the size, volume and distribution of the SB lesions, cardiovascular autonomic function testing and polysomnography. One patient with bilateral IRt involvement at both the rostral and caudal medulla had orthostatic hypotension (OH), absent HR(DB), abnormal Valsalva ratio, exaggerated fall of BP during phase II and absent phase IV during VM, and a dramatic fall of BP during head up tilt; this patient also had severe obstructive sleep apnea (OSA) and exhibited BP drops during each respiratory effort. A second patient, with bilateral IRt involvement restricted to the caudal medulla, had less severe cardiovascular autonomic dysfunction but also exhibited severe OSA. The other three patients had small SB cavities sparing the IRt and had sleep apnea but no autonomic dysfunction. Autonomic dysfunction could not be related to the size of the syrinx or the degree of atrophy in the cervical spinal cord in any of the five patients. Bilateral involvement of the IRt by SB produces cardiovascular autonomic failure and sleep apnea. In patients with more restricted lesions, autonomic and respiratory dysfunction may be dissociated. Clinico-radiological correlations using high resolution MRI assessment of medullary lesions can provide insight into the central organization of cardiovascular and respiratory control in humans.

We report, for the first time to our knowledge, theoretical and experimental results concerning a broadband and gain-flattened Er,Yb-codoped double-cladding-fiber amplifier, which provides up to 23-dBm output power in the wavelength region 1575 nm to 1605 nm.

The ability to measure step height and to calibrate step height artefacts is of vital interest in nanometrology. On that score the WGDM7 decided in 1998 to include measurements of step heights in a series of comparisons on the field of nanometrology. The comparison about step height (NANO2) started in September 2000 with the Physikalisch-Technische Bundesanstalt (PTB) as pilot laboratory. Fourteen national metrology institutes worldwide participated in this comparison. A set of five step height standards in the range from 7 nm to 800 nm was used for the comparison. The lateral size of the structures of the step height standards was chosen so that the height could be measured by different types of instruments, for example, interference microscopes, stylus instruments and scanning probe microscopes (SPM). The reference values were calculated as the weighted mean of all measurements that fulfilled the En?1 criteria. Most of the results were in good agreement with the reference values. It is noticeable that the results obtained by different types of instruments are quite compatible. Also this comparison is the first comprehensive test of the reliability of SPM and their suitability for traceable measurements of step heights. Further it was shown that today step heights on samples can be measured with uncertainties in the sub-nanometre range. Differences in the calculation of the uncertainty depend on the types of instruments and on the users. For each class of instrument, e.g. SPM, it would be meaningful to homogenise these models. Hence the results of this comparison are of great importance in many respects. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the Mutual Recognition Arrangement (MRA).

Starting from a theoretical approach, we present a detailed experimental characterization of interferometric noise, including different types of standard wavelength routing architectures suffering this phenomenon. We show that multi-path interference (MPI) causes alteration in the power spectral shape at the receiving site and ultimately introduces transmission power penalties. From a system standpoint, this means requiring a minimum crosstalk value in order to avoid impairments on the transmitted signal, due to interferometric noise.

We presented a novel configurable add/drop architecture operating on 100 GHz spaced channels and based on an innovative tunable filter. Propagation tests along five 25 dB fiber spans showed very good performance in term of channel OSNR and both in-band and out-of-band crosstalk.

Classical merosin (α2 laminin)-positive congenital muscular dystrophy is a heterogeneous subgroup of disorders; a few cases characterized by severe mental retardation, brain involvement and no ocular abnormalities were called Fukuyama-like congenital muscular dystrophy. We report a family of healthy non-consanguineous parents, with four affected siblings, of which one died at the age of 7 months due to an intercurrent illness, who presented congenital hypotonia, severe mental retardation, microcephaly, delayed psychomotor development, generalized muscular wasting and weakness with mild facial involvement, calf pseudohypertrophy, joint contractures and areflexia. Muscle biopsy disclosed severe muscular dystrophy. Immunostaining for laminin α2 80 kDa and clone Mer3/22B2 monoclonal antibodies, β1 and γ1 chain was preserved. Magnetic resonance imaging findings were consistent with pontocerebellar hypoplasia, bilateral opercular abnormalities and focal cortical dysplasia as well as minute periventricular white matter changes. Clusters of small T2-weighted focal hyperintensities in both cerebellar hemispheres consistent with cysts were observed in two of the three siblings studied with magnetic resonance imaging. Ophthalmologic and cardiologic examination was normal. Haplotype analysis using microsatellite markers excluded the Fukuyama congenital muscular dystrophy, LAMA2 and muscle-eye-brain disease loci. Thus, a wider spectrum of phenotypes, gene defects and protein deficiencies might be involved in congenital muscular dystrophy with brain abnormalities.

Surface composition and oxidation of the getter alloys Zr(V x Fe 1−x ) 2 , of the intermetallic compounds ZrMn 2 and TiFe, and of the elemental metals, Zr, Ti and Mn were studied by means of photoelectron spectroscopy after exposure to O 2 and heating up of 700 K. Good getter materials dissolve surface contaminants in the bulk upon activation at high temperature and are then very reactive at room temperature for gettering. The minimal temperature needed for activation is determined by the diffusion of oxygen, which varies strongly with bulk composition.

In 71 subjects with vascular atherosclerotic disease (VAD), in 32 VAD subjects with non-insulin-dependent diabetes mellitus (NIDDM) and in 31 normal controls, we evaluated polymorphonuclear leukocyte (PMN) membrane fluidity and PMN cytosolic Ca2+ content. The PMN membrane fluidity was obtained by marking intact and unstimulated PMN cells with fluorescent probe 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH) and the PMN cytosolic Ca2+ content was obtained by marking intact and unstimulated PMN cells with the fluorescent probe Fura 2-AM. From the obtained results, it is evident that PMN membrane fluidity does not differentiate normals from VAD subjects and VAD subjects with NIDDM, and normals from subjects with monovascular disease (MVAD) and polyvascular disease (PVAD) with and without NIDDM. The PMN cytosolic Ca2+ content is significantly increased in VAD subjects and VAD subjects with NIDDM, and also in MVAD and PVAD subjects with and without NIDDM. A positive correlation is present between PMN membrane fluidity and PMN cytosolic Ca2+ content in normals and VAD subjects, but not in VAD subjects with NIDDM. In conclusion, in VAD subjects with and without NIDDM, an increase of the PMN cytosolic Ca2+ content is present; this increase might be related to the PMN spontaneous activation.

Sixty uncomplicated hypertensive patients (40 stable and 20 borderline) were studied, by strain gauge plethysmography, in comparison with 25 normotensive subjects, in order to evaluate the arterial hemodynamics of the lower limbs in essential hypertension and to verify the different pattern in borderline and in stable hypertensives. Resting blood flow, even if lightly decreased in hypertensive groups, didn't show significant differences in its mean values; Peak Flow, instead, was reduced proportionally to the severity of hypertension in all the hypertensive patients, but only in the stable hypertensives did it prove statistically significant. Minimal Vascular Resistances showed a similar behaviour; they were significantly increased only in the stable hypertensives, whereas Basal Vascular Resistances, were raised in all hypertensive patients, in the borderline group too. Finally, half time and total hyperemic time, which indicate vascular reactivity, were significantly decreased in all hypertensives. These results suggest that the stable hypertensive patients principally develop arterial structural changes, while the borderline hypertensive patients have only functional modifications, such as a reduced compliance and a hyperdynamic condition.

To evaluate central nervous system involvement in diabetes, somatosensory (SEPs) and visual (VEPs) evoked potentials were investigated in a group of 35 patients and 20 sex, age-matched controls. In order to avoid methodological biases due to different type and duration of disease, we studied an omogeneous group of young insulin-dependent diabetics with ten or more year duration of disease. In our results VEP and SEP parameters were found abnormal in 10 (28%) patients, all of whom presenting clear signs of peripheral neuropathy. In diabetic patients median and tibial SEPs showed significant increase in absolute latency mean values of several components except interpeak intervals, as well as mean P 100 latencies were significantly increased in both eyes at 15' check size stimulation pattern. VEP and SEP components were not generally significantly associated with the indices of peripheral function. In contrast, in diabetics significant correlations were found between P 100 latencies and median SEP parameters including interpeak intervals. No major associations related VEP and SEP latencies to duration of diabetes and prevailing glycaemic control. In conclusion the central nervous system involvement in young insulin-dependent diabetics, even though diffusely present, seems unequivocally concomitant to peripheral conduction impairment.

Pulmonary hypertension in childhood is uncommon. It can be idiopathic or secondary to other pathologies (cardiovascular, skeletric,...).We report on a 9 year old girl suffering from pulmonary hypertension due to severe dorso-lumbar scoliosis.We discuss the etiopathogenetic relationship between scoliosis and pulmonary hypertension, with particular reference to the role of the treatment with Milwaukee's corset in the evolution of the disease.

Within the European iMERA-Plus project 'Traceable Characterisation of Nanoparticles' various particle measurement procedures were developed and finally a measurement comparison for particle size was carried out among seven laboratories across six national metrology institutes. Seven high quality particle samples made from three different materials and having nominal sizes in the range from 10 to 200 nm were used. The participants applied five fundamentally different measurement methods, atomic force microscopy, dynamic light scattering (DLS), small-angle x-ray scattering, scanning electron microscopy and scanning electron microscopy in transmission mode, and provided a total of 48 independent, traceable results. The comparison reference values were determined as weighted means based on the estimated measurement uncertainties of the participants. The comparison reference values have combined standard uncertainties smaller than 1.4 nm for particles with sizes up to 100 nm. All methods, except DLS, provided consistent results.

Magnetic Resonance Imaging (MRI) has amply shown its usefulness for the evaluation of traumatic cranio-encephalic lesions, particularly those involving the posterior fossa, due to the absence of bone artifacts, the availability of multiplanar sections and the greater sensitivity as regards Computerized Tomography (C. T.). We present an MRI examination of an extra-axial hematoma of the clivus in a child with head trauma, not visible on C. T. scans.