Search results for "BD"
showing 10 items of 3363 documents
Different coordination modes of a 1,1′,2,2′-ferrocenyltetraphosphine: Bi- and tri-dentate behaviour with group 6 and 7 transition metals
2002
The behaviour of 1,1′,2,2′-tetrakis(diphenylphosphino)-4,4′-di(tert-butyl)ferrocene (1), acting as a homoannular or heteroannular ligand, has been studied. Due to the cisoid disposition of the phosphino groups of each ring, different coordination modes are observed. With group 6 metal carbonyls, M(CO)6, the tetraphosphine acts exclusively as a tridentate ligand. In contrast, the reaction with MnCp(CO)3 leads to complexes showing 1,1′ and 1,2 bidentate coordination modes. All these complexes have been characterised by 1H and 31P NMR spectroscopy. The molecular structures of the molybdenum complex [(1)Mo(CO)3] (2b) and the 1,1′ manganese complex [(1)MnCp(CO)] (3) have been established by X-ra…
Synthesis and ROMP activity of aminophenol-substituted tungsten(VI) and molybdenum(VI) complexes
2008
Abstract Tungsten(VI) and molybdenum(VI) complexes [MO(L1)Cl2] and [M(X)(L2)Cl3] (X = O, NPh) with tridentate aminobis(phenolate) ligand L1 = methylamino-N,N-bis(2-methylene-4,6-dimethylphenolate) and bidentate aminophenolate ligand L2 = 2,4-di-tert-butyl-6-((dimethylamino)methyl)phenolate) were prepared and characterised. These complexes are principally stable in open atmosphere under ambient conditions. When activated with Et2AlCl, they exhibited high activity in ring-opening metathesis polymerisation (ROMP) of 2-norbornene (NBE) and its derivatives. Especially complexes [M(NPh)(L2)Cl3], which are easily available from corresponding metal oxides MO3 by a simple three-step synthesis, were …
Atomic absorption spectrometric determination of molybdenum in lubricating oils with use of emulsions
1985
Abstract Samples (0.1 g) containing molybdenum disulphide are digested with aqua regia or with a (1 + 1) hydrofluoric/nitric acid mixture, without complete destruction of the matrix, and the molybdenum is determined in an air/acetylene flame, after emulsification with a non-ionic surfactant (Nemol K-39). The detection limit is ca. 30 μg Mo g−1, and the r.s.d. is 2.9% for 6 analyses of a sample containing 6.5 mg Mo g−1.
Vanadium and molybdenum concentrations in particulate from Palermo (Italy): analytical methods using voltammetry
2014
The main purpose of this work was to develop a reliable method for the determination of vanadium (V) and molybdenum (Mo) in atmosphere particles or aerosols because they can not be readily measured using conventional techniques. For this research, 30 particulate samples were collected from five different stations located at Palermo, Italy. We used the catalytic adsorptive stripping voltammetry and differential pulsed voltammetry to measure Vand Mo in atmospheric particulate, respectively. The represented method includes advantages of high sensitivity, high selectivity, simplicity, reproducibility, speed and low costs. The quantification limits for V and Mo are, respectively, 0.57 and 0.80 n…
The biological activity of bacteriophage DNA, prepared by the cationic detergent dilution technique
1975
Abstract The preparation of phage lambda DNA infecting E. coli K 12 with cationic detergent is described. This DNA infects E. coli spheroblasts with the same efficiency as DNA prepared by phenol methods.
How Hox genes can shed light on the place of echinoderms among the deuterostomes.
2014
19 pages; International audience; BACKGROUND: The Hox gene cluster ranks among the greatest of biological discoveries of the past 30 years. Morphogenetic patterning genes are remarkable for the systems they regulate during major ontogenetic events, and for their expressions of molecular, temporal, and spatial colinearity. Recent descriptions of exceptions to these colinearities are suggesting deep phylogenetic signal that can be used to explore origins of entire deuterostome phyla. Among the most enigmatic of these deuterostomes in terms of unique body patterning are the echinoderms. However, there remains no overall synthesis of the correlation between this signal and the variations observ…
Environmental and ontogenetic constraints on developmental stability in the spatangoid sea urchin Echinocardium (Echinoidea).
2006
13 pages; International audience; Spatangoid irregular sea urchins are detritivorous benthic organisms particularly prone to variations of environment, and their mode of growth and plate morphology make them an appropriate model to assess the effects of environmental variations. Two populations of Echinocardium flavescens were sampled in two sites of the Norwegian coast characterized by contrasted environmental conditions. Different morphological descriptors (plate areas, interlandmarks distances, overall size, and shape of the posterior ambulacra) were used to appraise interindividual variations, and fluctuating asymmetry. The comparisons were carried out using classical fluctuating asymme…
Intestinal tuberculosis as a cause of chronic diarrhoea among patients with human immunodeficiency virus infection: report of two cases.
2001
In Western countries human immunodeficiency virus infection is considered the main risk factor of tuberculous disease, its incidence being 500 times higher in HIV-infected patients than in the general population. Despite the disease frequently present in these patients with extraintestinal manifestations, intestinal localization is rarely observed and often as a consequence of complications such as acute gastrointestinal bleeding or perforation. The diagnosis of intestinal tuberculosis is difficult and is often delayed due to the lack of specific signs and symptoms as well as the low sensitivity of routine methods. A review of the literature is made and personal experience in the diagnosis …
Subcutaneous octreotide versus oral loperamide in the treatment of diarrhea following chemotherapy
1993
Forty patients with chemotherapy-related diarrhea were randomized to receive (i) octreotide 0.5 mg three times per day s.c. or (ii) loperamide 4 mg three times per day p.o. until complete remission of diarrhea was achieved. In the octreotide group 80% of patients showed complete resolution of loose bowel movements within 4 days of therapy, while in the loperamide group this goal was obtained in only 30% of cases (p < 0.001). If after 4 days no benefit was seen, patients were considered to have failed antidiarrheal therapy. Failure was recorded in only one case (5%) treated with s.c. octreotide and in five patients (25%) who received loperamide. The mean duration of antidiarrheal therapy nec…
Chronic Diarrhea in a 5-Year-Old Girl: Pitfall in Routine Laboratory Testing with Potentially Severe Consequences
2009
A 5-year-old girl was referred because of recurrent watery diarrhea, abdominal pain, and flatulence. She was the second of 3 children. Her 10-year-old sister was normally developed and healthy. Her younger brother has meningomyelocele and hydrocephalus. At 1 year of age, the patient was admitted to the hospital for recurrent bronchitis, otitis media, food refusal, mild diarrhea, and abdominal distension since weaning. A sweat chloride analysis excluded cystic fibrosis. At that time, the patient’s laboratory results showed increased C-reactive protein (139 mg/L; reference interval, <5 mg/L) and moderate leukocytosis (14.6 × 109/L; reference interval, 4.5–13.5 × 109/L). Values for all other v…