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101.
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Mengyan Nie Julian A. Wharton Andy Cranny Nick R. Harris Robert J.K. Wood Keith R. Stokes 《Materials》2013,6(10):4345-4360
The ability to predict structural degradation in-service is often limited by a lack of understanding of the evolving chemical species occurring within a range of different microenvironments associated with corrosion sites. Capillary electrophoresis (CE) is capable of analysing nanolitre solution volumes with widely disparate concentrations of ionic species, thereby producing accurate and reliable results for the analysis of the chemical compositions found within microenvironment corrosion solutions, such as those found at crevice and pit corrosion sites. In this study, CE with contactless conductivity detection (CCD) has been used to characterize pitting and crevice corrosion solution chemistries for the first time. By using the capillary electrophoresis with contactless conductivity detection (CE-CCD) system, direct and simultaneous detection of seven metal cations (Cu2+, Ni2+, Fe3+, Fe2+, Cr3+, Mn2+, and Al3+) and chloride anions was achieved with a buffer solution of 10 mM 2,6-pyridinedicarboxylic acid and 0.5 mM cetyltrimethylammonium hydroxide at pH 4 using a pre-column complexation method. The detection limits obtained for the metal cations and chloride anions were 100 and 10 ppb, respectively. The CE-CCD methodology has been demonstrated to be a versatile technique capable of speciation and quantifying the ionic species generated within artificial pit (a pencil electrode) and crevice corrosion geometries for carbon steels and nickel-aluminium bronze, thus allowing the evolution of the solution chemistry to be assessed with time and the identification of the key corrosion analyte targets for structural health monitoring. 相似文献
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Acute renal embolism. Forty-four cases of renal infarction in patients with atrial fibrillation 总被引:6,自引:0,他引:6
Hazanov N Somin M Attali M Beilinson N Thaler M Mouallem M Maor Y Zaks N Malnick S 《Medicine》2004,83(5):292-299
Acute renal embolus is rarely reported in the medical literature; thus, accurate data regarding presentation, laboratory tests, diagnostic techniques, and treatment are lacking. To better define this condition, we examined the medical records of all patients admitted to Kaplan Medical Center and Sheba Medical Center in central Israel from 1984 to 2002 who had a diagnosis of renal infarction and atrial fibrillation. We noted demographic, clinical, and laboratory parameters; method of diagnosis; treatment received; and patient outcome. We identified 44 cases of renal embolus: 23 females and 21 males, with an average age of 69.5 +/- 12.6 years. Thirty (68%) patients had abdominal pain, and 6 (14%) had a previous embolic event. Nine patients were being treated with warfarin on admission, 6 (66%) of whom had an international normalized ratio (INR) < 1.8. Hematuria was present in 21/39 (54%), and 41 (93%) patients had a serum lactate dehydrogenase (LDH) level > 400 U/dL. The mean LDH was 1100 +/- 985 U/dL. Diagnostic techniques included renal isotope scan, which was abnormal in 36/37 cases (97%); contrast-enhanced computed tomography (CT) scan, which was diagnostic in 12/15 cases (80%); and ultrasound, which was positive in only 3/27 cases (11%). Angiography was positive in 10/10 cases (100%). Twenty-three (61%) of 38 patients had normal renal function on follow-up. The 30-day mortality was 11.4%. Renal embolus was diagnosed mainly in patients aged more than 60 years, some of whom had a previous embolic event. Most of those receiving anticoagulant therapy had a subtherapeutic INR. Abdominal pain was common, as well as hematuria and an elevated LDH. These patients are at risk of subsequent embolic events to other organs. The most sensitive diagnostic technique in this population is a renal isotope scan, but contrast-enhanced CT scan requires further assessment. 相似文献
106.
Osborne AH Vance D Rohling EJ Barton N Rogerson M Fello N 《Proceedings of the National Academy of Sciences of the United States of America》2008,105(43):16444-16447
It is widely accepted that modern humans originated in sub-Saharan Africa approximately 150-200 thousand years ago (ka), but their route of dispersal across the currently hyperarid Sahara remains controversial. Given that the first modern humans north of the Sahara are found in the Levant approximately 120-90 ka, northward dispersal likely occurred during a humid episode in the Sahara within Marine Isotope Stage (MIS) 5e (130-117 ka). The obvious dispersal route, the Nile, may be ruled out by notable differences between archaeological finds in the Nile Valley and the Levant at the critical time. Further west, space-born radar images reveal networks of-now buried-fossil river channels that extend across the desert to the Mediterranean coast, which represent alternative dispersal corridors. These corridors would explain scattered findings at desert oases of Middle Stone Age Aterian lithic industries with bifacial and tanged points that can be linked with industries further to the east and as far north as the Mediterranean coast. Here we present geochemical data that demonstrate that water in these fossil systems derived from the south during wet episodes in general, and penetrated all of the way to the Mediterranean during MIS 5e in particular. This proves the existence of an uninterrupted freshwater corridor across a currently hyperarid region of the Sahara at a key time for early modern human migrations to the north and out of Africa. 相似文献
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Grant S. Lipman David Pomeranz Patrick Burns Caleb Phillips Mary Cheffers Kristina Evans Carrie Jurkiewicz Nick Juul Peter Hackett 《The American journal of medicine》2018,131(2):200.e9-200.e16
Background
Inhaled budesonide has been suggested as a novel prevention for acute mountain sickness. However, efficacy has not been compared with the standard acute mountain sickness prevention medication acetazolamide.Methods
This double-blind, randomized, placebo-controlled trial compared inhaled budesonide versus oral acetazolamide versus placebo, starting the morning of ascent from 1240 m (4100 ft) to 3810 m (12,570 ft) over 4 hours. The primary outcome was acute mountain sickness incidence (headache and Lake Louise Questionnaire ≥3 and another symptom).Results
A total of 103 participants were enrolled and completed the study; 33 (32%) received budesonide, 35 (34%) acetazolamide, and 35 (34%) placebo. Demographics were not different between the groups (P > .09). Acute mountain sickness prevalence was 73%, with severe acute mountain sickness of 47%. Fewer participants in the acetazolamide group (n = 15, 43%) developed acute mountain sickness compared with both budesonide (n = 24, 73%) (odds ratio [OR] 3.5, 95% confidence interval [CI] 1.3-10.1) and placebo (n = 22, 63%) (OR 0.5, 95% CI 0.2-1.2). Severe acute mountain sickness was reduced with acetazolamide (n = 11, 31%) compared with both budesonide (n = 18, 55%) (OR 2.6, 95% CI 1-7.2) and placebo (n = 19, 54%) (OR 0.4, 95% CI 0.1-1), with a number needed to treat of 4.Conclusion
Budesonide was ineffective for the prevention of acute mountain sickness, and acetazolamide was preventive of severe acute mountain sickness taken just before rapid ascent. 相似文献109.
Nick Scott Jonathan P. Caulkins Alison Ritter Paul Dietze 《Addiction Research & Theory》2015,23(6):459-468
Background: Understanding of substitution patterns in drug using careers is limited. Between 2009 and mid-2013, the purity-adjusted price of methamphetamine declined sharply in Melbourne in absolute terms and relative to the purity-adjusted price of heroin. We determine whether there were associated increases among people who inject drugs (PWID) in (1) use of methamphetamine and (2) citing methamphetamine as the drug of choice. Method: Responses to “drug of choice” and “most used drug” were obtained from baseline and follow-up interviews of the 688 PWID enrolled in the Melbourne Injecting Drug User Cohort Study between April 2008 and August 2013, categorised as heroin, methamphetamine, cannabis or other. Previous month heroin and methamphetamine use was reported at baseline by 82% and 41% of participants, respectively, and 51% had completed four or more interviews in this period. A Markov model that included marginal effects for methamphetamine purity-adjusted price was used to calculate (1) transitions between drug of choice and (2) conditional probabilities for most used drug. Parameters were determined by fitting multinomial logistic models to appropriate data subsets. Results: At baseline, the majority of participants reported heroin as both their preferred drug and the drug they used most. There were no significant increases in reports of methamphetamine as drug of choice, or as the most used drug. Conclusion: In a cohort of PWID who reported a range of drug behaviours, there was little evidence of drug substitution into methamphetamine, despite substantial declines in its purity-adjusted price. 相似文献
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