Linear alkane polymerization on a gold surface

In contrast to the many methods of selectively coupling olefins, few protocols catenate saturated hydrocarbons in a predictable manner. We report here the highly selective carbon-hydrogen (C-H) activation and subsequent dehydrogenative C-C coupling reaction of long-chain (>C(20)) linear alkanes on an anisotropic gold(110) surface, which undergoes an appropriate reconstruction by adsorption of the molecules and subsequent mild annealing, resulting in nanometer-sized channels (1.22 nanometers in width). Owing to the orientational constraint of the reactant molecules in these one-dimensional channels, the reaction takes place exclusively at specific sites (terminal CH(3) or penultimate CH(2) groups) in the chains at intermediate temperatures (420 to 470 kelvin) and selects for aliphatic over aromatic C-H activation.     

High-resolution NMR spectroscopy with a portable single-sided sensor

We report construction of a portable nuclear magnetic resonance sensor with a single-sided open probe design. The resulting magnetic field inhomogeneity is compensated by a pulse sequence that takes advantage of parallel inhomogeneity in the applied radio frequency field. We can thereby acquire fluorine-19 spectra of liquid fluorocarbons with 8 parts per million resolution, surmounting the long-standing obstacle of obtaining chemical shift information with open probe instruments.     

Combination anesthesia in sheep with ketamine-(fentanyl)-guaifenesin (My 301)-laughing gas-halothane

The concept of combined anaesthesia, the centrally-acting muscle relaxant guaifenesin (My 301) in a 5% solution with ketamine (and/or fentanyl) in addition to the inhalation of nitrous oxide and halothane is based upon the principle of "balanced anaesthesia". Guaifenesin amplifies the effect of several anaesthetics, which complement one another, allowing the dosage to be decreased and thereby reducing the cardiovascular stress. To induce anaesthesia, the combination of a cataleptic anaesthetic (ketamine = Ketanest, Ketolar) and a centrally acting skeletal muscle relaxant (guaifenesin = Myolaxin, My 301) is used. Because of the risk of aspiration the animal should be intubated as soon as possible. Anaesthesia will be prolonged by the carrier gas nitrous oxide (65%, weakly analgesic)/oxygen (65%), low concentrations of halothane (1.0 to 0.6 to 0.4%, weakly hypnotic and analgesic) and by a continuous drip infusion of 5% guaifenesin (relaxing, mild analgesic and sedative). The effect of all the other anaesthetics is increased by guaifenesin. To increase the analgesia and to control the cardiovascular parameters the additional injection of ketamine or fentanyl is recommended. The recovery period is short and the general condition is good both after a lengthy anaesthesia of 9 hours (n = 32) and after anaesthesia of 2 hours. No significant adverse effects on the cardiovascular system were detected.     

High frequency of hypermutable Pseudomonas aeruginosa in cystic fibrosis lung infection

The lungs of cystic fibrosis (CF) patients are chronically infected for years by one or a few lineages of Pseudomonas aeruginosa. These bacterial populations adapt to the highly compartmentalized and anatomically deteriorating lung environment of CF patients, as well as to the challenges of the immune defenses and antibiotic therapy. These selective conditions are precisely those that recent theoretical studies predict for the evolution of mechanisms that augment the rate of variation. Determination of spontaneous mutation rates in 128 P. aeruginosa isolates from 30 CF patients revealed that 36% of the patients were colonized by a hypermutable (mutator) strain that persisted for years in most patients. Mutator strains were not found in 75 non-CF patients acutely infected with P. aeruginosa. This investigation also reveals a link between high mutation rates in vivo and the evolution of antibiotic resistance.     

Monitoring the helmintological situation in a large-scale reproduction of pigs]

In 1976 to 1978, the occurrence of helminths in a large reproduction herd of pigs was studied in different age categories of the animals kept. Six helminth species were found in 30.7% of the sows: Ascaris suum (6.6%), Oesophagostomum dentatum (24.0%), Hyostrongylus rubidus (3.3%), Trichocephalus suis (1.3%), Strongyloides ransomi (0.7%), Metastrongylus sp. (0.3%). Four- to seven-month-old auction gilts had only the eggs of A. suum (4% of all cases). No helminith eggs were found in fattened piglets. Breeding boars were invaded by the species O. dentatum, H. rubidus and Metastrongylus sp. In elite herds and in gilts introduced from these herds, a higher extensity of invasion by different helminth species was found during quarantine and the findings even included the eggs of the species Capillaria sp. The anthelmintic effectiveness of Helmirazin (SpOFA) was also tested: in A. suum its effectiveness was 77.1%, in O. dentatum 66.2%, in T. suis the preparation remained ineffective. The technology of large-scale pig breeding under the conditions of reproduction herd of the PM-013-AGP type appears to be suitable from the helminthological points of view. In the planned introduction of animals from other breeding establishments it is necessary to subject the gilts to double treatment with an effective anthelmintic.     

Correlation of the highest-energy cosmic rays with nearby extragalactic objects

Using data collected at the Pierre Auger Observatory during the past 3.7 years, we demonstrated a correlation between the arrival directions of cosmic rays with energy above 6 x 10(19) electron volts and the positions of active galactic nuclei (AGN) lying within approximately 75 megaparsecs. We rejected the hypothesis of an isotropic distribution of these cosmic rays with at least a 99% confidence level from a prescribed a priori test. The correlation we observed is compatible with the hypothesis that the highest-energy particles originate from nearby extragalactic sources whose flux has not been substantially reduced by interaction with the cosmic background radiation. AGN or objects having a similar spatial distribution are possible sources.     

Composted MSW Effects on Soil Properties and Native Vegetation in a Degraded Semiarid Shrubland

Three rates of dried composted MSW (40, 80 and 120 Mg ha^?1) were surface applied to a degraded semiarid shrubland site near Madrid in central Spain. Various soil and plant parameters were determined one year after its application. MSW amendment had an effect on soil chemistry and nutrient levels. Available P and K, concentration of N-NO₃ and EC. increased significantly after the MSW application. The concentration of total soil heavy metals, Zn, Pb, Cd, Ni, Cr and Cu rose with the application of MSW as compared with the control plot, but these increases were only significant in total Zn, Pb and Cu. Zn and Cu amounts of DTPA-extractable soil were also significantly higher in the amended soil. Total plant cover increased significantly in the plots treated with low and intermediate MSW rates. Total biomass production increased as compost rates were added but this rise is not proportional to the amount of MSW added. The degraded soil used in this study may require MSW rates up to 80 Mg ha^?1 to improve soil chemical properties as well as to produce minimal changes in the native vegetation.     

Transformation of benzoxazinones and derivatives and microbial activity in the test environment of soil ecotoxicological tests on Poecilus cupreus and Folsomia candida

Benzoxazinones, such as 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) and 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA), and benzoxazolinones, such as 6-methoxy-2-benzoxazolinone (MBOA) and 2-benzoxazolinone (BOA), are biologically active secondary metabolites found in cereals. Because these compounds could be exploited as part of a strategy for reducing the use of synthetic pesticides, ecotoxicological tests were performed recently. In this paper, the transformation of the compounds in the test environment of the ecotoxicological tests was studied. DIMBOA was degraded and partly transformed to MBOA during the period of ecotoxicological testing of the compounds. During testing of MBOA on Poecilus cupreus test media the analysis showed that at the initial concentrations of 2 and 10 mg kg(-1) no MBOA was left after 45 days of testing, but the metabolite 2-amino-phenoxazin-3-one (AMPO) was formed. During testing of BOA on both Folsomia candida and Poecilus cupreus the more biologically active compound 2-amino-phenoxazin-3-one (APO) was formed. Thus, the ecotoxicological test results on MBOA and BOA were partly due to the microbial transformation of the compounds during the time of testing.