A Laboratory Investigation of An Accelerated Polishing Method for Determining the Skid Resistance Potential of Aggregates, MLR-76-02 and R-264, 1976

An initial feasibility study indicated that the "Purdue Accelerated Polishing Method" gave repeatable results when testing the skid resistance of laboratory specimens. The results also showed a rough correlation with the field performance of the same aggregate sources. The research was then expanded to include all available asphalt aggregates. The results of the expanded study indicated that the method is not presently capable of developing and measuring the full skid potential of the various aggregate sources. Further research in the area of polishing times and/or pressures is needed.

Agronomic performance, chromosomal stability and resistance to velvetbean caterpillar of transgenic soybean expressing cry1Ac gene

The objective of this work was to analyze the agronomic performance and chromosomal stability of transgenic homozygous progenies of soybean [Glycine max (L.) Merrill.], and to confirm the resistance of these plants against Anticarsia gemmatalis. Eleven progenies expressing cry1Ac, hpt and gusA genes were evaluated for agronomic characteristics in relation to the nontransformed parent IAS 5 cultivar. Cytogenetical analysis was carried out on transgenic and nontransgenic plants. Two out of the 11 transgenic progenies were also evaluated, in vitro and in vivo, for resistance to A. gemmatalis. Two negative controls were used in resistance bioassays: a transgenic homozygous line, containing only the gusA reporter gene, and nontransgenic 'IAS 5' plants. The presence of cry1Ac transgene affected neither the development nor the yield of plants. Cytogenetical analysis showed that transgenic plants presented normal karyotype. In detached-leaf bioassay, cry1Ac plants exhibited complete efficacy against A. gemmatalis, whereas negative controls were significantly damaged. Whole-plant feeding assay confirmed a very high protection of cry1Ac against velvetbean caterpillar, while nontransgenic 'IAS 5' plants and homozygous gusA line exhibited 56.5 and 71.5% defoliation, respectively. The presence of cry1Ac transgene doesn't affect the majority of agronomic traits (including yield) of soybean and grants high protection against A. gemmatalis.

French Swiss physicians' attitude toward palliative sedation: Influence of prognosis and type of suffering.

OBJECTIVE: Palliative sedation is a last resort medical act aimed at relieving intolerable suffering induced by intractable symptoms in patients at the end-of-life. This act is generally accepted as being medically indicated under certain circumstances. A controversy remains in the literature as to its ethical validity. There is a certain vagueness in the literature regarding the legitimacy of palliative sedation in cases of non-physical refractory symptoms, especially "existential suffering." This pilot study aims to measure the influence of two independent variables (short/long prognosis and physical/existential suffering) on the physicians' attitudes toward palliative sedation (dependent variable). METHODS: We used a 2 × 2 experimental design as described by Blondeau et al. Four clinical vignettes were developed (vignette 1: short prognosis/existential suffering; vignette 2: long prognosis/existential suffering; vignette 3: short prognosis/physical suffering; vignette 4: long prognosis/physical suffering). Each vignette presented a terminally ill patient with a summary description of his physical and psychological condition, medication, and family situation. The respondents' attitude towards sedation was assessed with a six-point Likert scale. A total of 240 vignettes were sent to selected Swiss physicians. RESULTS: 74 vignettes were completed (36%). The means scores for attitudes were 2.62 ± 2.06 (v1), 1.88 ± 1.54 (v2), 4.54 ± 1.67 (v3), and 4.75 ± 1.71 (v4). General linear model analyses indicated that only the type of suffering had a significant impact on the attitude towards sedation (F = 33.92, df = 1, p = 0.000). Significance of the results: The French Swiss physicians' attitude toward palliative sedation is more favorable in case of physical suffering than in existential suffering. These results are in line with those found in the study of Blondeau et al. with Canadian physicians and will be discussed in light of the arguments given by physicians to explain their decisions.

Tomato plant inheritance of antixenotic resistance to tomato leafminer

The objective of this work was to determine the inheritance of resistance by antixenosis in tomato plants (Lycopersicon esculentum) to tomato leafminer [Tuta absoluta (Lepidoptera: Gelechiidae)]. Evaluations were performed for tomato plants of the generations P1, P2, F1, F2, RC1 and RC2. The measured characteristic in the parents, BGH-1497 (P2 male) and 'Santa Clara' (P1 female), and in the F1, F2, RC1 and RC2 generations was the number of eggs per plant. This number was converted to the oviposition nonpreference index. The inheritance of antixenosis resistance of genotype BGH-1497 is ruled by a gene of greater effect and polygenes in epistatic interactions, with a phenotypic proportion of 13:3 between susceptible and resistant genotypes, respectively.

Characterization of cowpea genotype resistance to Callosobruchus maculatus

The objective of this work was to characterize the resistance of 50 cowpea (Vigna unguiculata) genotypes to Callosobruchus maculatus. A completely randomized design with five replicates per treatment (genotype) was used. No-choice tests were performed using the 50 cowpea genotypes to evaluate the preference for oviposition and the development of the weevil. The genotypes IT85 F-2687, MN05-841 B-49, MNC99-508-1, MNC99-510-8, TVu 1593, Canapuzinho-1-2, and Sanzi Sambili show non-preference-type resistance (oviposition and feeding). IT81 D-1045 Ereto and IT81 D-1045 Enramador exhibit antibiosis against C. maculatus and descend from resistant genitors, which grants them potential to be used in future crossings to obtain cowpea varieties with higher levels of resistance.

Activity of dalbavancin, alone and in combination with rifampicin, against meticillin-resistant Staphylococcus aureus in a foreign-body infection model.

The activity of dalbavancin, a representative of the lipoglycopeptide antibiotics, alone and in combination with rifampicin, was investigated against meticillin-resistant Staphylococcus aureus (MRSA) in a foreign-body infection model in guinea pigs. The MIC, MBC and time-kill profile of dalbavancin were determined for MRSA ATCC 43300 in the logarithmic (MBClog) and stationary (MBCstat) growth phases. The pharmacokinetic profile of dalbavancin was determined in sterile cage fluid in guinea pigs. The activity of intraperitoneal dalbavancin (40, 60 or 80mg/kg as a single dose), rifampicin (12.5mg/kg/12h for 4 days) and their combination was assessed against planktonic and biofilm MRSA. The MIC of dalbavancin was 0.078mg/L; MBClog and MBCstat were both >128Ã- MIC. In time-kill studies, bacterial reduction of 3log10CFU/mL was achieved after 48h at â0/00¥32Ã- MIC (logarithmic growth) and at â0/00¥1Ã- MIC (stationary growth). Dalbavancin was neither synergistic nor antagonistic with rifampicin, and prevented the emergence of rifampicin resistance in vitro. The half-life of dalbavancin in cage fluid was 35.8-45.4h and the concentration remained above the MIC of MRSA during 7 days after a single dose. Dalbavancin reduced planktonic MRSA in cage fluid at high dose (60mg/kg and 80mg/kg) but failed to eradicate biofilm MRSA from cages. In combination with rifampicin, dalbavancin at 80mg/kg cured 36% of infected cages, and emergence of rifampicin resistance was completely prevented. Dalbavancin at 80mg/kg and in combination with rifampicin eradicated approximately one-third of cage-associated MRSA infections and prevented emergence of rifampicin resistance.

Transfer of penicillin resistance between Neisseriae in microcosm

Horizontal gene transfer between commensal and pathogenic Neisseriae is the mechanism proposed to explain how pathogenic species acquire altered portions of the penA gene, which encodes penicillin binding protein 2. These changes resulted in a moderately penicillin-resistant phenotype in the meningococci, whose frequency of isolation in Spain increased at the end of the 1980s. Little has been published about the possibility of this gene transfer in nature or about its simulation in the laboratory. We designed a simple microcosm, formed by solid and liquid media, that partially mimics the upper human respiratory tract. In this microcosm, penicillin-resistant commensal strains and the fully susceptible meningococcus were co-cultivated. The efficiency of gene transfer between the strains depended on the phase of bacterial growth and the conditions of culture. Resistance of penicillin was acquired in different steps irrespective of the source of the DNA. The presence of DNase in the medium had no effect on gene transfer, but it was near zero when nicked DNA was used. Cell-to-cell contact or membrane blebs could explain these results. The analysis of sequences of the transpeptidase domain of PBP2 from transformants, and from donor and recipient strains demonstrated that the emergence of moderately resistant transformants was due to genetic exchange between the co-cultivated strains. Finally, mechanisms other than penA modification could be invoked to explain decreased susceptibility

Experimental study of clinafloxacin alone and in combination in the treatment of ciprofloxacin-susceptible and -resistant pneumococcal meningitis

The increasing incidence of ciprofloxacin resistance in Streptococcus pneumoniae may limit the efficacy of the new quinolones in difficult-to-treat infections such as meningitis. The aim of the present study was to determine the efficacy of clinafloxacin alone and in combination with teicoplanin and rifampin in the therapy of ciprofloxacin-susceptible and ciprofloxacin-resistant pneumococcal meningitis in rabbits. When used against a penicillin-resistant ciprofloxacin-susceptible strain (Clinafloxacin MIC 0.12 μg/ml), clinafloxacin at a dose of 20 mg/kg per day b.i.d. decreased bacterial concentration by -5.10 log cfu/ml at 24 hr. Combinations did not improve activity. The same clinafloxacin schedule against a penicillin- and ciprofloxacin-resistant strain (Clinafloxacin MIC 0.5 μg/ml) was totally ineffective. Our data suggest that a moderate decrease in quinolone susceptibility, as indicated by the detection of any degree of ciprofloxacin resistance, may render these antibiotics unsuitable for the management of pneumococcal meningitis

Transfer of penicillin resistance between Neisseriae in microcosm

Horizontal gene transfer between commensal and pathogenic Neisseriae is the mechanism proposed to explain how pathogenic species acquire altered portions of the penA gene, which encodes penicillin binding protein 2. These changes resulted in a moderately penicillin-resistant phenotype in the meningococci, whose frequency of isolation in Spain increased at the end of the 1980s. Little has been published about the possibility of this gene transfer in nature or about its simulation in the laboratory. We designed a simple microcosm, formed by solid and liquid media, that partially mimics the upper human respiratory tract. In this microcosm, penicillin-resistant commensal strains and the fully susceptible meningococcus were co-cultivated. The efficiency of gene transfer between the strains depended on the phase of bacterial growth and the conditions of culture. Resistance of penicillin was acquired in different steps irrespective of the source of the DNA. The presence of DNase in the medium had no effect on gene transfer, but it was near zero when nicked DNA was used. Cell-to-cell contact or membrane blebs could explain these results. The analysis of sequences of the transpeptidase domain of PBP2 from transformants, and from donor and recipient strains demonstrated that the emergence of moderately resistant transformants was due to genetic exchange between the co-cultivated strains. Finally, mechanisms other than penA modification could be invoked to explain decreased susceptibility

Corrosion resistance improvement of titanium base alloys

The corrosion resistance of the new Ti-6Al-4V-1Zr alloy in comparison with ternary Ti-6Al-4V alloy in Ringer-Brown solution and artificial Carter-Brugirard saliva of different pH values was studied. In Ringer-Brown solution, the new alloy presented an improvement of all electrochemical parameters due to the alloying with Zr; also, impedance spectra revealed better protective properties of its passive layer. In Carter-Brugirard artificial saliva, an increase of the passive film thickness was proved. Fluoride ions had a slight negative influence on the corrosion and ion release rates, without to affect the very good stability of the new Ti-6Al-4V-1Zr alloy.

Expression of resistance in rice hybrids to Pyricularia grisea

Thirty-nine rice (Oryza sativa) hybrids and their restorers were assessed for vertical resistance to Pyricularia grisea in the rice blast nursery, and in artificial inoculation tests with two pathotypes, under controlled greenhouse conditions. The hybrids were developed from cytoplasmic genetic male sterile lines 046I and IR 58025A, derived from WA cytoplasm. In the rice blast nursery all hybrids showed susceptible reaction varying from 5 to 9. Compatible and incompatible leaf blast reactions of hybrids to two pathotypes, IC-1 and IB-45, were observed in inoculation tests. A majority of the hybrids were resistant when the restorer was resistant. However, seven of the 25 F1 hybrids exhibited susceptible reactions even when one of the parents was resistant to a pathotype. The partial resistance of 11 hybrids and their parents that showed compatible reactions to two pathotypes was analyzed. Differential interaction between isolates and genotypes was observed for partial resistance in relation to both disease severity and lesion number indicating the specific nature of partial resistance.

Evaluation of genetic mixtures of sorghum lines for anthracnose resistance management

The main objective of this work was to evaluate the diversification of sorghum (Sorghum bicolor) populations as a way to manage resistance to the sorghum anthracnose fungus Colletotrichum graminicola. A total of 18 three-way hybrids were obtained by crossing six single cross male-sterile F1 hybrids, derived by crossing A (non restorer sterile cytoplasm) and B (non restorer normal cytoplasm) lines, with three fertile R (restorer) lines, previously evaluated for their differential reaction to the pathogen. Variation in the level of resistance was observed, as indicated by the values of the area under the disease progress curve (AUDPC) obtained for each hybrid. Lines contributed differently to the level of resistance of each hybrid. All hybrids in which CMSXS169R was the male progenitor were classified as highly resistant. Some hybrids had a level of resistance superior to the maximum levels of each line component individually.

Evaluation of phenotypic stability of resistance to Phytophthora spp. in cacao clones

Resistance of fourteen Theobroma cacao clones to Phytophthora spp. was evaluated using stem inoculations on grafted seedlings. Concepts of phenotypic stability were used to interpret the results and to express horizontality of the resistance. The linear regression coefficient 'b', the determination coefficient (R²) and average lesion size were used to determine the level of horizontal resistance, the phenotypic stability and the predictability of all clones. The results indicated that clones P 7 and MA 15 present highest levels of horizontal resistance and stability, but with moderate predictability. Clones CAS 1 and CEPEC 13 were classified as those with high horizontal resistance, stability and predictability, while clones PA 30, UF 650 and SIAL 88 and EET 59 showed intermediate resistance and stability and high predictability. Clones SPA 17, OC 61, PA 150, SIAL 505, ICS 1 and R 41 presented high susceptibility and intermediate or low stability and moderate or high predictability.

Simultaneous determination of Cd and Pb in antibiotics used in sugar-cane fermentation process by GFAAS

A method has been developed for the simultaneous determination of Cd and Pb in antibiotics used in sugar-cane fermentation by GFAAS. The integrated platform of transversely heated graphite atomizer was treated with tungsten to form a coating of tungsten carbide. Six samples of commercial solid antibiotics were analyzed by injecting 20 µL of digested samples into the pretreated graphite platform with co-injection of 5 µL of 1000 mg L-1 Pd as chemical modifier. Samples were mineralized in a closed-vessel microwave-assisted acid-digestion system using nitric acid plus hydrogen peroxide. The pyrolysis and atomization temperatures of the heating program of the atomizer were selected as 600°C and 2200°C, respectively. The calculated characteristic mass for Cd and Pb was 1.6 pg and 42 pg, respectively. Limits of detection (LOD) based on integrated absorbance were 0.02 µg L-1 Cd and 0.7 µg L-1 Pb and the relative standard deviations (n = 10) for Cd and Pb were 5.7% and 8.0%, respectively. The recoveries of Cd and Pb added to the digested samples varied from 91% to 125% (Cd) and 80% to 112% (Pb).

Inheritance of resistance to powdery mildew in pea and pathogenesis-related aspects

The inheritance of resistance to powdery mildew in the pea cultivar MK-10 and some histological aspects of infection were assessed. For the inheritance study, F1, F2, backcrosses and F3 generations of MK-10 crossed with two susceptible populations were evaluated. Histological evaluations included percentage of germinated conidia, percentage of conidia that formed appresoria, percentage of conidia that established colonies, and number of haustoria per colony. Segregation ratios obtained in the resistance inheritance study were compared by Chi-square (ײ) test and the histological data were analyzed by Tukey's test at 5% probability. It was concluded that resistance of MK-10 to powdery mildew is due to a pair of recessive alleles since it is expressed in the pre-penetration stage and completed by post-penetration localized cellular death, characteristic of the presence of the pair of recessive alleles er1er1.