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11.
Van Zelm R Huijbregts MA van Jaarsveld HA Reinds GJ de Zwart D Struijs J van de Meent D 《Environmental science & technology》2007,41(3):922-927
This paper describes a new approach in life-cycle impact assessment to derive characterization factors for acidification in European forests. Time horizon dependent characterization factors for acidification were calculated, whereas before only steady-state factors were available. The characterization factors indicate the change in the potential occurrence of plant species due to a change in emission, and they consist of a fate and an effect factor. The fate factor combines the results of an atmospheric deposition model and a dynamic soil acidification model. The change in base saturation in soil due to an atmospheric emission change was derived for 20, 50, 100, and 500 year time horizons. The effect factor was based on a dose-response curve of the potential occurrence of plant species, derived from multiple regression equations per plant species. The results showed that characterization factors for acidification increase up to a factor of 13 from a 20 years to a 500 years time horizon. Characterization factors for ammonia are 4.0-4.3 times greater than those for nitrogen oxides (NO(x)), and characterization factors for sulfur dioxide are 1.4-2.0 times greater than those for NO(x). Aggregation of damage due to acidification with other impact categories on the European scale becomes feasible with the applied approach. 相似文献
12.
BC van Jaarsveld P Krijnen FH Derkx HY Oei CT Postma MA Schalekamp 《Canadian Metallurgical Quarterly》1997,157(11):1226-1234
BACKGROUND: Renal scintigraphy with radiolabeled pentetic acid (diethylenetriamine pentaacetic acid [DTPA]) or, more recently, mertiatide (mercaptoacetyltriglycine [MAG3]), with or without captopril challenge, is widely recommended as a diagnostic test for renal artery stenosis. OBJECTIVES: To address (1) whether the diagnostic accuracy has been improved by the use of captopril and the introduction of mertiatide and (2) whether a renal scan that shows abnormalities is a useful criterion to select patients for renal arteriography. PATIENTS AND METHODS: A standard diagnostic protocol, using both scintigraphy and arteriography, was followed in 505 consecutive high-risk hypertensive patients who were evaluated for renovascular hypertension at the University Hospital Dijkzigt, Rotterdam, the Netherlands, from 1978 to 1992. RESULTS: Renal artery stenosis (> or = 50%) was present in 263 patients. When the single-kidney fractional uptake was used as a diagnostic criterion, a specificity of 0.90 was obtained at a cutoff value of 35% for the worst kidney in scintigraphy using pentetic acid without captopril challenge (n = 225) and at a cutoff value of 37% after captopril challenge (n = 280). This was associated with sensitivity levels of 0.65 and 0.68, respectively. The difference between the uptake of pentetic acid with and without captopril challenge in the 85 patients who were studied under both circumstances was no more accurate as a predictor of renal artery stenosis. In the 93 patients who were studied with mertiatide as well as with pentetic acid, both after captopril challenge, the diagnostic accuracy was no better with mertiatide than with pentetic acid; mertiatide failed to offer any advantage not only when the single-kidney fractional uptake was used as a criterion, but also with the use of other scintigraphic parameters (eg, time to peak, time to pyelum, overall shape of renographic curve, and kidney size). CONCLUSIONS: The diagnostic accuracy of renal scintigraphy has not been improved by the introduction of mertiatide or by the use of captopril. The usefulness of scintigraphy as a diagnostic test for the presence of renal artery stenosis remains questionable. The physician will always confront either a substantial number of arteriograms that do not show abnormalities when renal scintigraphy is omitted as a screening step or a substantial number of missed diagnoses when a renal scan that shows abnormalities is used as a prerequisite for arteriography. 相似文献
13.
Daniela I. Bezuidenhout Belinda van der Westhuizen Nina A. van Jaarsveld Simon Lotz 《Journal of Inorganic and Organometallic Polymers and Materials》2014,24(1):39-57
The preparation and the features of the ring activation in π-arene metal (chromium, manganese) complexes are discussed. The bottom-up approach to the synthesis of σ, π-bi- and multimetal complexes, and the synthesis of cyclometallated and multicyclic complexes from a variety of selected routes are also reviewed. The stereochemical features of such complexes, and their applications in carbon–carbon coupling reactions and metal insertion reactions are highlighted. The redox reactivities and selected applications of (multi)metal π-arene complexes in catalysis and organic synthesis are included. Finally, the extension of the multimetal π-arene complexes to larger assemblies is shown. The importance of arene ring substituents in the basic mononuclear units and their use as bidentate metalloligands, with bidentate amines as linkers, in the construction of polymers, metal organic frameworks, networks (also on nanoparticles or silica supports), is highlighted. 相似文献
14.
Hagedoorn Mari?t; Van Yperen Nico W.; Coyne James C.; van Jaarsveld Cornelia H. M.; Ranchor Adelita V.; van Sonderen Eric; Sanderman Robbert 《Canadian Metallurgical Quarterly》2006,21(3):611
The association between marital status and distress was examined in a largely neglected group, namely older people (65 and older; N = 1,649). In this 2-wave study, married persons were less distressed than single persons, but perceived equity within the marriage and recency of bereavement qualified these findings. Married persons who felt inequitably treated were more distressed than persons who had always been single. Married persons reported less distress than recently (= 2 years ago) widowed persons, but only equitably treated married persons reported less distress than persons widowed for more than 2 years. Increased distress between the 2 waves occurred in recently widowed persons, and there was a decrease in distress in persons who were widowed shortly before the 1st wave. No gender effects were found. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
15.
HY Tichelaar PJ van Jaarsveld CM Smuts M Marais MC Mdhluli M Kruger AJ Benadé 《Canadian Metallurgical Quarterly》1998,27(5):240-243
A sexually intact, male Chihuahua and a spayed female poodle were presented with left perineal masses. The masses were identified as perineal hernias by rectal palpation. Surgical exploration of the perineal region in each dog revealed retroperitoneal fat protruding between the sacrotuberous ligament and the coccygeus muscle (sciatic perineal hernia). The hernias were repaired using modifications of the standard or internal obturator flap herniorrhaphies. The levator ani muscle was grossly and histologically normal in the Chihuahua and grossly normal in the poodle. No short- or long-term complications were reported in either case. The management of sciatic perineal hernia is similar to the more common caudal perineal hernia. 相似文献
16.
A COMPARATIVE STUDY OF KAOLINITE VERSUS METAKAOLINITE IN FLY ASH BASED GEOPOLYMERS CONTAINING IMMOBILIZED METALS 总被引:3,自引:0,他引:3
J. G. S. Van Jaarsveld J. S. J. Van Deventer G. C. Lukey 《Chemical Engineering Communications》2004,191(4):531-549
Geopolymer technology has emerged as an effective solution for the stabilization of industrial by-products and the immobilization of heavy metals. It has been established that the nature of the source materials used during synthesis has a significant effect on the final chemical and physical properties of the geopolymeric matrix. In particular, it has been established that the partial dissolution of specific wastes serves to either weaken or strengthen the newly formed structure. Moreover, leaching tests have shown that the use of either kaolinite or calcined kaolinite (metakaolinite) in fly ash based geopolymers affects the propensity of the matrix to immobilize heavy metals. This observation has practical implications for the application of geopolymer technology to the capping of mine tailings ponds or the backfilling of mines. The differences in dissolution behavior and the effect on final properties of geopolymeric materials have been studied for the kaolinite and metakaolinite system, with a view of gaining a wider appreciation of the behavior of other systems that are more difficult to study. 相似文献
17.
The effects of curing agents (NaCl, nitrate, ascorbic acid and glucose) and processing parameters (pH, temperature and cooking temperatures) on cathepsins B, H and L activities were investigated. NaCl, nitrate, ascorbic acid and glucose exhibited different influences on ostrich cathepsin B, B+L and H activities. In the range 20-60gl(-1), NaCl inhibited cathepsin B+L and H activities. All three cysteine proteinase activities were inhibited by up to 8g ascorbic acid l(-1). With the exception of cathepsin B activity, which was inhibited by glucose, nitrate and glucose had very little effect on cathepsin B, B+L and H activities. Cathepsins B and D were active at 65 and 69°C and might play an important degradative role during the cooking of meat and meat products. Cathepsins B, B+L and H were optimally active at temperatures of 40-45°C and 50°C, and were still quite active at the low temperatures used in the dry-curing process; they showed maximum activity in the pH range 5·5-7. A simulation of the three stages of the dry-curing process of hams revealed that cathepsins B and B+L might play an important role throughout the complete process, whereas cathepsin H could only participate in the middle and at the end of the dry-curing process. Although ostrich cathepsins show many properties similar to those from other species, the present study also revealed some interesting distinguishing features. 相似文献
18.
A clinical prediction rule for renal artery stenosis 总被引:1,自引:0,他引:1
P Krijnen BC van Jaarsveld EW Steyerberg AJ Man in 't Veld MA Schalekamp JD Habbema 《Canadian Metallurgical Quarterly》1998,129(9):705-711
BACKGROUND: Renal artery stenosis is a rare cause of hypertension. The gold standard for diagnosing renal artery stenosis, renal angiography, is invasive and costly. OBJECTIVE: To develop a prediction rule for renal artery stenosis from clinical characteristics that can be used to select patients for renal angiography. DESIGN: Logistic regression analysis of data from a prospective cohort of patients suspected of having renal artery stenosis. A prediction rule was derived from the regression model for use in clinical practice. SETTING: 26 hypertension clinics in The Netherlands. PATIENTS: 477 hypertensive patients who underwent renal angiography because they had drug-resistant hypertension or an increase in serum creatinine concentration during therapy with angiotensin-converting enzyme inhibitors. RESULTS: Age, sex, atherosclerotic vascular disease, recent onset of hypertension, smoking history, body mass index, presence of an abdominal bruit, serum creatinine concentration, and serum cholesterol level were selected as predictors. The regression model was reliable (goodness-of-fit test, P > 0.2) and discriminated well between patients with stenosis and those with essential hypertension (area under the receiver-operating characteristic curve, 0.84). The diagnostic accuracy of the regression model was similar to that of renal scintigraphy, which had a sensitivity of 72% and a specificity of 90%. CONCLUSIONS: In the diagnostic workup of patients suspected of having renal artery stenosis, the clinical prediction rule can be considered as an alternative to renal scintigraphy. It can help to select patients for renal angiography in an efficient manner by reducing the number of angiographic procedures without the risk for missing many renal artery stenoses. 相似文献
19.
The effect of Ca ions and ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid (EGTA) on myofibrillar protein degradation showed that when ostrich iliotibialis lateralis muscle was incubated with 10 mM EGTA at 2–4 °C for 24 hr, the activity of extracted cathepsin H was unchanged compared with a buffer-incubated sample. Ca++ had no effect on extracted cathepsin H activity, while that of Ca2+-dependent protease (CDP) decreased significantly (p < 0.05). Ca2+-treatment enhanced post-mortem changes observed in myofibrillar protein patterns (production of fragments around 30 K) that were not observed in EGTA-incubated myofibrils. The effect of storage time on shear force, CDP activity, cathepsin B, D, H and L activities and the SDS-PAGE pattern of myofibrils showed a time-dependent reduction in CDP activity. Of the cathepsins studied only cathepsin H showed a reduction (40%) in activity. The most prominent component appearing on storage at 2–4 °C had a Mr of 27 K. The incubation of myofibrils with CDP mimicked the post-mortem changes. CDP may be responsible for some of the post-mortem changes observed, although shear force measurements suggest these changes do not lead to significant tenderisation. 相似文献