Real-time organic aerosol chemical speciation in the indoor environment using extractive electrospray ionization mass spectrometry

Understanding the sources and composition of organic aerosol (OA) in indoor environments requires rapid measurements, since many emissions and processes have short timescales. However, real-time molecular-level OA measurements have not been reported indoors. Here, we present quantitative measurements, at a time resolution of five seconds, of molecular ions corresponding to diverse aerosol-phase species, by applying extractive electrospray ionization mass spectrometry (EESI-MS) to indoor air analysis for the first time, as part of the highly instrumented HOMEChem field study. We demonstrate how the complex spectra of EESI-MS are screened in order to extract chemical information and investigate the possibility of interference from gas-phase semivolatile species. During experiments that simulated the Thanksgiving US holiday meal preparation, EESI-MS quantified multiple species, including fatty acids, carbohydrates, siloxanes, and phthalates. Intercomparisons with Aerosol Mass Spectrometer (AMS) and Scanning Mobility Particle Sizer suggest that EESI-MS quantified a large fraction of OA. Comparisons with FIGAERO-CIMS shows similar signal levels and good correlation, with a range of 100 for the relative sensitivities. Comparisons with SV-TAG for phthalates and with SV-TAG and AMS for total siloxanes also show strong correlation. EESI-MS observations can be used with gas-phase measurements to identify co-emitted gas- and aerosol-phase species, and this is demonstrated using complementary gas-phase PTR-MS observations.     

Lateral ion implant straggle and mask proximity effect

Lateral scattering of retrograde well implants is shown to have an effect on the threshold voltage of nearby devices. The threshold voltage of both NMOSFETs and PMOSFETs increases in magnitude for conventional retrograde wells, but for triple-well isolated NMOSFETs the threshold voltage decreases for narrow devices near the edge of the well. Electrical data, SIMS, and SUPREM4 simulations are shown that elucidate the phenomenon.     

Transjugular intrahepatic portosystemic shunts (TIPS) in children

The transjugular intrahepatic portosystemic shunt procedure is an accepted treatment for adults with complications of portal hypertension. We performed a retrospective review of all pediatric TIPS placements performed at the University of California, San Francisco between 1990 and 1996. Twelve procedures were attempted in nine children, with a mean age (+/- SD) of 9.4 +/- 3.9 years (range, 5 to 15 years) and a mean weight of 31 +/- 18 kg (range, 16 to 70 kg). The indications for TIPS placement were portal hypertension complicated by chronic variceal hemorrhage not controlled with sclerotherapy (n = 7) and hypersplenism with thrombocytopenia (n = 2). TIPS placement was successfully completed initially in seven of nine (78%) patients. Unfavorable vascular anatomy was the cause of failure in two cases. The seven patients who underwent successful TIPS placement were followed up for an average of 136 days (range, 1 to 800 days); two still have patent shunts, three underwent liver transplantation, one had a splenorenal shunt after stenosis, and one died of underlying liver disease. Variceal bleeding was controlled in four of five patients who successfully underwent TIPS placement. Shunt occlusion occurred in four patients; patency was restored by transjugular shunt revision in three, and a splenorenal shunt was performed in one.     

Influence of caloric intake on aging and on the response to stressors

Reducing the food intake of rodents to well below that of ad libitum fed animals increases the life span. This action, which gerontologists often refer to as the antiaging action of dietary restriction (DR), is due to the slowing of the aging processes. DR also maintains most physiological processes in a youthful state and delays the occurrence and/or slows the progression of age-associated disease processes. This antiaging action of DR results from the reduced intake of calories. Reduction of the body fat content does not play a causal role in the antiaging action of DR, nor does reduction in the metabolic rate. Alterations in the characteristics of carbohydrate metabolism and of oxidative metabolism in response to DR have been found that are of such a nature that they could, at least in part, underlie the antiaging action. Several theories have recently been proposed in regard to the mechanisms responsible for the antiaging action of DR, but none has been tested by rigorously designed studies. Of these theories, the one that seems most promising is based on the fact that DR protects rats and mice of all ages against the damaging actions of acute stressors. This protective action against stressors may play a major role in the antiaging action of DR.     

Recurrent erosion after photorefractive keratectomy

Recurrent erosion of the corneal epithelium has been treated successfully by phototherapeutic keratectomy when convention therapy has failed. We present a case of recurrent corneal erosion occurring 1 year after photorefractive keratectomy in a 55-year-old myopic woman. No corneal abnormalities were previously identified in either the affected or the fellow eye. This case demonstrates the potential for ineffective healing of the corneal epithelial basement membrane complex after excimer laser photorefractive keratectomy.     

Recurrent Epstein-Barr virus-associated lesions in organ transplant recipients

This paper discusses the problem of violence and its expression upon mortality due to external causes. A few indicators are offered, which have been worked upon it to emphasise the importance of the theme. In a general way, the study demonstrates violent death has had its magnitude increased along the years, not only throughout Latin America but also in Brazil and in Santa Catarina.     

Time-frequency plane Wiener filtering of the high-resolution ECG: background and time-frequency representations

The diel 'activity', i.e. availability, of Ixodes ricinus larvae, nymphs and adults was investigated in a meadow and a forest habitat near Stockholm during 1991-1993. Generally, the immature ticks were more prevalent in the forest than in the meadow. In the meadow, the mean larval and adult numbers varied significantly between 4 h time intervals with the peak activity from 2300 to 0300 h. In the forest, the tick numbers did not differ significantly between the time intervals. The association of the tick activity with certain meteorological variables was strongest in the meadow, where the mean numbers of all tick stages were negatively correlated with the temperature. The relative humidity was positively correlated only with the mean numbers of larvae. In contrast, the larval activity in the forest was positively and negatively correlated with the temperature and relative humidity, respectively, while the nymphal and adult activity showed no association with these climatic variables. The impact of the host activity on the tick diel activity is also discussed.     

The pharmacokinetics and protein-binding of fusidic acid in patients with severe renal failure requiring either haemodialysis or continuous ambulatory peritoneal dialysis

Antibiotic treatment options for Burkholderia cepacia infection are limited because of high intrinsic resistance. The problem is complicated by development of cross-resistance between antibiotics of different classes. We isolated antibiotic-resistant mutants by stepwise exposure to chloramphenicol (Chlor) and to trimethoprim/sulphamethoxazole (T/S) for four B. cepacia strains: ATCC13945, Per (clinical isolate), Cas and D4 (environmental isolates). Chlor(r) mutants did not produce chloramphenicol acetyl-transferase. Cross-resistance, defined as greater than four-fold increase in MIC by microtitre dilution method, was consistently seen in both types of mutants. For chloramphenicol-resistant (Chlor[r]) and trimethoprim/sulphamethoxazole-resistant (Tr/Sr) mutants of B. cepacia ATCC13945 and Cas, no MIC change was seen for piperacillin, ceftazidime, rifampicin, gentamicin, tobramycin, polymyxin B or azithromycin. B. cepacia-Per and -D4 mutants showed cross-resistance to ceftazidime and to piperacillin. Comparison of outer membrane protein (OMP) profiles of B. cepacia and their mutants by SDS-PAGE revealed Tr/Sr) mutants to be deficient in a major OMP (molecular weight 39-47 kDa). Tr/Sr mutants also expressed additional OMPs not found in wild type strains at 75-77 kDa for B. cepacia-ATCC13945 and -Cas, and 20-21 kDa in B. cepacia-D4 and -Per. No OMP changes occurred in Chlor(r) mutants. Lipopolysaccharide (LPS) profiles of each type of mutant showed new high and low molecular weight LPS bands. Cross-resistance seems to be mediated by alterations in porin and LPS for Tr/Sr mutants, but only by LPS in Chlor(r) mutants.     

Professor Gerard Jonderko--life and achievements of the honorary member of the Polish Society of Internal Medicine

Between February 1995 to August 1997, 120 patients underwent elective stent implantation for isolated proximal left anterior descending coronary artery stenosis. Their age ranged from 31 to 72 years (mean: 50.8 +/- 10.2) and the majority (89%) were males. All patients had angina, documented myocardial ischemia or both and 70 percent or more luminal diameter stenosis in the proximal left anterior descending before the origin of any branch. Majority (62.5%) of the treated lesions were type A. Successful deployment of the stent at the target site was achieved in all patients without any major in-hospital complications, including myocardial infarction, emergency bypass graft surgery or death. Clinical follow-up, ranging from 6 to 31 months (mean: 18.5 +/- 8.1, median: 20), was available in 87 out of 92 (94.5%) eligible patients who had completed at least six months after the procedure. Freedom from angina, myocardial infarction, target lesion revascularization and death was observed in 90.8, 100, 95.4 and 97.7 percent of patients, respectively. By the Kaplan-Meier estimate, an event-free survival (absence of death, myocardial infarction, recurrence of angina or revascularization) was 95.4 percent at six months, 89.5 percent at 12 and 18 months and 82.7 percent at 24 to 31 months of follow-up. Only 10 (11.5%) patients developed any event and TLR was required in 4.6 percent of patients. In conclusion, elective stenting for isolated proximal left anterior descending stenosis can be achieved safely and successfully in all patients without any adverse in-hospital events. This modality of treatment also provides long-term benefits in terms of reduction in major cardiovascular events and need for subsequent revascularization.