Depth profiling and standardization from the back side of a sample for accurate analyses: Emphasis on quantifying low-fluence, shallow implants in diamond-like carbon.

RATIONALE: Back-side thinning of wafers is used to eliminate issues with transient sputtering when analyzing near-surface element distributions. Precise and accurate calibrated implants are created by including a standard reference material during the implantation. Combining these methods allows accurate analysis of low-fluence, shallow features even if matrix effects are a concern. METHODS: Implanted Na (<2.0 × 1011 ions/cm2 , peaking <50 nm) in diamond-like carbon (DLC) film on silicon (solar wind returned by NASA's Genesis mission) was prepared for measurement as follows. Implanted surfaces of samples were epoxied to wafers and back-side-thinned using physical or chemical methods. Thinned samples were then implanted with reference ions for accurate quantification of the solar wind implant. Analyses used a CAMECA IMS 7f-GEO SIMS in depth-profiling mode. RESULTS: Back-side-implanted reference ions reduced the need to change sample mounts or stage position and could be spatially separated from the solar wind implant even when measuring monoisotopic ions. Matrix effects in DLC were mitigated and the need to find an identical piece of DLC for a reference implant was eliminated. Accuracy was only limited by the back-side technique itself. CONCLUSIONS: Combining back-side depth profiling with back-side-implanted internal standards aides quantification of shallow mono- and polyisotopic implants. This technique helps mitigate matrix effects and keeps measurement conditions consistent. Depth profile acquisition times are longer, but if sample matrices are homogeneous, procedural changes can decrease measurement times.

Hydrogen fluence in Genesis collectors: Implications for acceleration of solar wind and for solar metallicity.

NASA's Genesis mission was flown to capture samples of the solar wind and return them to the Earth for measurement. The purpose of the mission was to determine the chemical and isotopic composition of the Sun with significantly better precision than known before. Abundance data are now available for noble gases, magnesium, sodium, calcium, potassium, aluminum, chromium, iron, and other elements. Here, we report abundance data for hydrogen in four solar wind regimes collected by the Genesis mission (bulk solar wind, interstream low-energy wind, coronal hole high-energy wind, and coronal mass ejections). The mission was not designed to collect hydrogen, and in order to measure it, we had to overcome a variety of technical problems, as described herein. The relative hydrogen fluences among the four regimes should be accurate to better than ±5-6%, and the absolute fluences should be accurate to ±10%. We use the data to investigate elemental fractionations due to the first ionization potential during acceleration of the solar wind. We also use our data, combined with regime data for neon and argon, to estimate the solar neon and argon abundances, elements that cannot be measured spectroscopically in the solar photosphere.

Loop diuretics can cause clinical natriuretic failure: a prescription for volume expansion.

Ultrafiltration enhances volume removal and weight reduction vs diuretics. However, their differential impact on total body sodium, potassium, and magnesium has not been described. Fifteen patients with congestion despite diuretic therapy had urine electrolytes measured after a diuretic dose. Ultrafiltration was initiated and ultrafiltrate electrolytes were measured. The urine sodium after diuretics (60+/-47 mmol/L) was less than in the ultrafiltrate (134+/-8.0 mmol/L) (P=.000025). The urine potassium level after diuretics (41+/-23 mmol/L) was greater than in the ultrafiltrate (3.7+/-0.6 mmol/L) (P=.000017). The urine magnesium level after diuretics (5.2+/-3.1 mg/dL) was greater than in the ultrafiltrate (2.9+/-0.7 mg/dL) (P=.017). In acute decompensated heart failure patients with congestion despite diuretic therapy, diuretics are poor natriuretics and cause significant potassium and magnesium loss. Ultrafiltration extracts more sodium while sparing potassium and magnesium. The sustained clinical benefits of ultrafiltration compared with diuretics may be partly related to their disparate effects on total body sodium, potassium, and magnesium, in addition to their differential efficacy of volume removal.

Constraints on neon and argon isotopic fractionation in solar wind.

To evaluate the isotopic composition of the solar nebula from which the planets formed, the relation between isotopes measured in the solar wind and on the Sun's surface needs to be known. The Genesis Discovery mission returned independent samples of three types of solar wind produced by different solar processes that provide a check on possible isotopic variations, or fractionation, between the solar-wind and solar-surface material. At a high level of precision, we observed no significant inter-regime differences in 20Ne/22Ne or 36Ar/38Ar values. For 20Ne/22Ne, the difference between low- and high-speed wind components is 0.24 +/- 0.37%; for 36Ar/38Ar, it is 0.11 +/- 0.26%. Our measured 36Ar/38Ar ratio in the solar wind of 5.501 +/- 0.005 is 3.42 +/- 0.09% higher than that of the terrestrial atmosphere, which may reflect atmospheric losses early in Earth's history.

Large volume ultrafiltration for acute decompensated heart failure using standard peripheral intravenous catheters.

BACKGROUND: Ultrafiltration for decompensated heart failure has recently generated significant clinical interest with the development of a portable machine that does not require an intensive care or dialysis unit. This case series was designed to demonstrate the feasibility and effectiveness of performing large volume ultrafiltration via peripherally inserted standard intravenous (IV) catheters in patients with acute decompensated heart failure. METHODS AND RESULTS: Nine hospitalized patients with decompensated heart failure underwent peripheral ultrafiltration (PUF) therapy with peripheral IV catheters. The mean length of time of PUF therapy was 33.3 +/- 20.0 hours with a mean volume removed of 7.0 +/- 4.9 L. All patients experienced a statistically significant mean weight loss of 6.2 +/- 5.0 kg, P = .01. There was no statistically significant change in renal function. CONCLUSION: We report the first successful implementation of ultrafiltration via standard peripheral IV catheters to remove a large volume of fluid over an extended period of time reliably in a small group of patients. The ability to use PUF therapy via peripheral IV catheters will potentially allow this therapy to be implemented more easily in a variety of care settings to treat patients with resistant heart failure.