Molecular and ionic sublimation of erbium tribromide

The molecular and ionic composition of vapor over erbium tribromide sublimed from the Knudsen effusion cell and the open surface of a single crystal was studied by high-temperature mass spectrometry. The partial pressures of ErBr3 and Er2Br6 molecules in saturated vapor and the ratio between their sublimation coefficients under free vaporization conditions were determined. The enthalpies and activation energies of sublimation of ErBr3 crystals in the form of monomers and dimers were calculated. The emission of and Er2 was recorded in studies of ionic sublimation in both modes. The enthalpies of formation of gas molecules and ions were determined.

Development of a multifunctional platform for extra- and intracellular ionic activities recording

We present the development of a multifunctional platform equipped with an array of silicon nitride micropipettes with dimensions allowing the implementation of extra- and intracellular operations. Micropipettes with outer diameter that ranges from 6 mum down to 300 nm and with walls thicknesses of 500 down to 150 nm are presented. The generic technology developed to fabricate these micropipettes has a number of advantages, including the ability to be implemented as ion-selective electrodes for (A) intracellular and (B) extracellular recordings and as (C) local drug microdispensers.

Development of an array of ion-selective microelectrodes aimed for the monitoring of extracellular ionic activities

In this study, we present the development and the characterization of a generic platform for cell culture able to monitor extracellular ionic activities (K+, NH4+) for real-time monitoring of cell-based responses, such as necrosis, apoptosis, or differentiation. The platform for cell culture is equipped with an array of 16 silicon nitride micropipet-based ion-selective microelectrodes with a diameter of either 2 or 6 microm. This array is located at the bottom of a 200-microm-wide and 350-microm-deep microwell where the cells are cultured. The characterization of the ion-selective microelectrode arrays in different standard and physiological solutions is presented. Near-Nernstian slopes were obtained for potassium- (58.6 +/- 0.8 mV/pK, n = 15) and ammonium-selective microelectrodes (59.4 +/- 3.9 mV/pNH4, n = 13). The calibration curves were highly reproducible and showed an average drift of 4.4 +/- 2.3 mV/h (n = 10). Long-term behavior and response after immersion in physiological solutions are also presented. The lifetime of the sensors was found to be extremely long with a high recovery rate.

Distal radius attachments of the radiocarpal ligaments: an anatomical study

Background Understanding the anatomy of the ligaments of the distal radius aids in the surgical repair of ligamentous injuries and the prediction of intraarticular fracture patterns. Purposes (1) to measure the horizontal and vertical distances of the origins of the radiocarpal ligaments from the most ulnar corner of the sigmoid notch and the joint line, respectively; and (2) to express them as a percentile of the total width of the bony distal radius. Methods We dissected 8 cadaveric specimens and identified the dorsal radiocarpal, radioscaphocapitate, and the long and short radiolunate ligaments. Results The dorsal radiocarpal ligament attached from the 16th to the 52nd percentile of the radial width. The radioscaphocapitate ligament attached around the radial styloid from the 86th percentile volarly to the 87th percentile dorsally. The long radiolunate ligament attached from the 59th to the 85th percentile, and the short radiolunate ligament attached from the 14th to the 41st percentile. Discussion There was a positive correlation between the radial width and the horizontal distance of the ligaments from the sigmoid notch. These findings may aid individualized surgical repair or reconstruction adjusted to patient size and enable further standardized research on distal radial fractures and their relationship with radiocarpal ligaments.

Climatic drivers of hourly to yearly tree radius variations along a 6°C natural warming gradient

Climate affects the timing, rate and dynamics of tree growth, over time scales ranging from seconds to centuries. Monitoring how a tree's stem radius varies over these time scales can provide insight into intra-annual stem dynamics and improve our understanding of climate impacts on tree physiology and growth processes. Here, we quantify the response of radial conifer stem size to environmental fluctuations via a novel assessment of tree circadian cycles. We analyze four years of sub-hourly data collected from 56 larch and spruce trees growing along a natural temperature gradient of ∼6 °C in the central Swiss Alps. During the growing season, tree stem diameters were greatest at mid-morning and smallest in the late evening, reflecting the daily cycle of water uptake and loss. Along the gradient, amplitudes calculated from the stem radius cycle were ∼50% smaller at the upper site (∼2200 m a.s.l.) relative to the lower site (∼800 m a.s.l.). We show changes in precipitation, temperature and cloud cover have a substantial effect on typical growing season diurnal cycles; amplitudes were nine times smaller on rainy days (>10 mm), and daily amplitudes are approximately 40% larger when the mean daily temperature is 15–20 °C than when it is 5–10 °C. We find that over the growing season in the sub-alpine forests, spruce show greater daily stem water movement than larch. However, under projected future warming, larch could experience up to 50% greater stem water use, which may severely affect future growth on already dry sites. Our data further indicate that because of the confounding influences of radial growth and short-term water dynamics on stem size, conventional methodology probably overstates the effect of water-linked meteorological variables (i.e. precipitation and relative humidity) on intra-annual tree growth. We suggest future studies use intra-seasonal measurements of cell development and consider whether climatic factors produce reversible changes in stem diameter. These study design elements may help researchers more accurately quantify and attribute changes in forest productivity in response to future warming.

Oxygen Isotopic and Soluble Ionic Composition of a Shallow Firn Core, Inilchek Glacier, Central Tien Shan

Oxygen isotopic and soluble ionic measurements made on snow-pit (2 in depth) and firn-core (12.4 m depth samples recovered from the accumulation zone 5100 m) of Inilchek glacier 43degrees N, 79degrees E) provide information on recent (1992-98) climatic and environmental conditions in the central Tien Shan region of central Asia. The combined 14.4 m snow-pit/firn-core profile lies within the firn zone, arid contains only one observed melt feature (10 m temperature = - 12 degreesC), Although some post-depositional attenuation of the sub-seasonal delta(18)O record is possible, annual cycles are apparent throughout the isotope profile. We therefore use the preserved delta(18)O record to establish a depth/age scale for the core. Mean delta(18)O values for the entire core and for summer periods are consistent with delta(18)O/temperature observations, and suggest the delta(18)O record provides a means to reconstruct past changes in summer surface temperature at the site. Major-ion (Na(+), K(+), Mg(2+), Ca(2+), NH(4)(+), Cl(-), NO(3)(-), SO(4)(2-)) data from the core demonstrate the dominant influence of dust deposition on the soluble chemistry at the site, arid indicate significant interannual variability in atmospheric-dust loading during the 1900s. Anthropogenic impacts oil NH(4)(+) concentrations are observed at the site, and suggest a summer increase in atmospheric NH(4)(+) that may be related to regional agricultural (nitrogen-rich fertilizer use activities.

Measurement of the jet radius and transverse momentum dependence of inclusive jet suppression in lead-lead collisions at sqrtsNN=2.76 TeV with the AT detector

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at root S-NN = 2.76 TeV corresponding to an integrated luminosity of approximately 7 mu b(-1), ATLAS has measured jets with a calorimeter system over the pseudorapidity interval vertical bar eta vertical bar < 2.1 and over the transverse momentum range 38 < pT <210 GeV. Jets were reconstructed using the anti-k(t) algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," R-CP. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. R-CP varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.