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961.
J Gilvarry MJ Buckley S Beattie H Hamilton CA O''Morain 《Canadian Metallurgical Quarterly》1997,32(6):535-540
The efficient production of polyprotonated oligonucleotides, studied at n < or = 19, occurs from water/propan-2-ol solutions over an ammonium acetate concentration range between 2.5 and 40 mm and a pH range from 5 to 11. Average charge-state levels observed were approximately half of those found in mass spectra of polyanionic oligonucleotides, reflecting differences in sites of ionization: heterocyclic bases for protonation and phosphodiester backbone for deprotonation. Collision-induced dissociation mass spectra show three principal reaction paths: (1) release of protonated bases, with abundances dictated largely by base proton affinity; (2) phosphodiester chain cleavage at C3'-O3' indicative of sequence in the 3'-->5' direction; and (3) chain cleavage concomitant with base loss giving furan-type ions indicative of sequence in the 5'-->3' direction, analogous to reactions of polyanionic oligonucleotides. Thymine residues undergo very little protonation, resulting in characteristic absence of phosphodiester cleavage on the 3' side of T sites, producing mass-ladder gaps representing dinucleotides. 相似文献
962.
Schaller Mark; Boyd Carrie; Yohannes Jonathan; O'Brien Meredith 《Canadian Metallurgical Quarterly》1995,68(3):544
Two studies explored the relation between personal need for structure (PNS) and a reasoning process through which stereotypes may form. Participants viewed information about the performance of group members on intelligence-related tasks and then indicated their inference strategies and impressions of the groups. Results indicated that high-PNS participants were more likely than low-PNS participants to form erroneous group stereotypes. Individual differences in attributional complexity and need for cognition also predicted stereotype formation under some conditions. The effects of PNS and other cognitive personality variables were weakened under conditions in which participants believed that they would have to justify their impressions publicly. Discussion focuses on processes underlying the relation between PNS and stereotype formation and on relations among personality, social context, and social inference. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
963.
Previous studies of the effects of infection of Wistar rats with the common liver fluke, Fasciola hepatica, on liver bioenergetic and drug metabolism have demonstrated a loss of respiratory control in isolated mitochondria and reduced microsomal cytochrome P450 content, respectively, from 2 weeks post-infection throughout the acute phase of the infection. In the present study male Balb/c mice infected with F. hepatica showed a loss of respiratory control in isolated liver mitochondria only at 4 weeks post-infection. A similar time course was demonstrated for a reduction in hepatic microsomal cytochrome P450 content. Preparations from infected CBA mice showed similar changes to Balb/c mice but mitochondrial respiration in preparations from infected Swiss outbred mice was normal. A host difference between strains of mice and between mice and rats is therefore evident in the timing and extent of liver mitochondrial dysfunction and in the timing of the decrease in the cytochrome P450 content of hepatic microsomes. This difference between hosts may be related to the reported differences in cellular inflammatory responses to the migrating juvenile flukes in the livers of rats and mice. 相似文献
964.
King Andrew P.; Freeberg Todd M.; West Meredith J. 《Canadian Metallurgical Quarterly》1996,110(3):276
Longitudinal vocal records of 26 juvenile male cowbirds from 2 populations (Molothrus ater ater and Molothrus ater artemisiae) were analyzed to look for susceptibility to social influence from either female cowbirds or heterospecifics. Within each population, 1 group of males was individually housed with female conspecifics, and the other with pairs of canaries (Serinus canaria). Evidence was found for female influence in both populations. M. a. artemisiae males showed more vulnerability to heterospecific influence and developed song more slowly than did M. a. ater males. Greater vocal production was correlated with faster acquisition of song, especially for the males housed with female conspecifics. In that female cowbirds do not sing, these data indicate the inadequacy of mechanisms based on imitation to explain vocal ontogeny. The data also reinforce the need to consider the intraspecific impact of social and ecological parameters on vocal learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
965.
From the 1990 National Health Interview Survey Health Promotion and Disease Prevention supplement, the authors estimated the 1990 baseline prevalence of breast cancer screening among employed U.S. women aged 50-70 years. Proportions of women screened for breast cancer were calculated by occupational category and demographic characteristics, and were compared with the Healthy People 2000 objective that 60% of women aged 50 and older have had mammography and a clinical breast examination within the preceding two years. The objective was exceeded for white-collar workers (61.8%) and workers with some college (64.1%), but was not met by any blue-collar/service workers (40.8%); or any workers with only a high school diploma (54.7%) or less than a high school diploma (38.5%). Identification of occupational categories and demographic subgroups among working women will be helpful to those planning breast cancer screening programs, in both the public and the private sectors. 相似文献
966.
GE Meredith A Pattiselanno HJ Groenewegen SN Haber 《Canadian Metallurgical Quarterly》1996,365(4):628-639
The neurochemical division of the rodent nucleus accumbens into shell and core is now a widely accepted concept. However, such divisions in the primate nucleus accumbens have yet to be fully clarified and described. In the present study, the forebrains of three primates--marmoset, rhesus monkey, and human--and a Wistar rat, were immunoreacted with antibodies directed against calbindin-D28k. The patterns of immunoreactivity in the primates' ventral striatum were mapped and compared to that of rat. Calbindin staining was uneven in all species and there was no evidence of a bicompartmental organization, i.e., striosome/patch and matrix, in central parts of the nucleus. Nucleus accumbens in primates, as in rat, could be divided immunohistochemically into a crescent-shaped outer shell--medially, ventrally and laterally--and an inner core. In general, medial parts of the shell stained less intensely for calbindin than did lateral parts. However, interspecific variation in the intensity of the immunoreactive staining and the mediolateral extent of the shell was obvious. The core, which immunostained unevenly, was consistently more intensely immunoreactive than either medial or lateral shell in all species except the marmoset. These results suggest that the neurochemical subdivisions of shell and core established for nucleus accumbens of rodents are also present in primates. However, further work is needed to establish whether these territories are homologous and, if so, the full extent of that homology. 相似文献
967.
The cytologic features of squamous cell carcinoma in situ with endocervical gland involvement have been described in cervical smears. We evaluated the presence of two types of cellular fragments in 43 cervical smears of high grade squamous intraepithelial lesions (HGSIL) to assess their ability to predict glandular involvement by HGSIL in subsequent cone biopsies. An endocervical brush was used to obtain all endocervical specimens. Of 16 cases without glandular involvement, fragments were present in 13 smears. Of 27 cases with glandular involvement, fragments were absent in 11 smears. No statistical association was identified between the presence of abnormal cellular fragments on cervical smears of HGSIL and endocervical gland involvement on cone biopsies. 相似文献
968.
LD Ormerod JA Larkin CA Margo PR Pavan MM Menosky DO Haight JP Nadler BG Yangco SM Friedman R Schwartz JT Sinnott 《Canadian Metallurgical Quarterly》1998,26(1):34-45; discussion 46-7
Eleven patients with rapidly progressive herpetic retinal necrosis (RPHRN) complicating AIDS were investigated retrospectively to study the disease spectrum, systemic involvement, and therapy. The mean CD4 cell count was 24/microL. There was a characteristic disease pattern with rapid progression, 82% bilaterality, relative resistance to intravenous antiviral therapy, and 70% retinal detachment. Varicella-zoster virus was the probable cause in 10 patients (detected by polymerase chain reaction in two eyes investigated), and herpes simplex virus was the probable cause in one. Cutaneous zoster occurred previously in 73% but was not concurrent. Seventy-three percent had central nervous system disease, possibly virus-related. RPHRN may be a local herpetic recrudescence in an immune-privileged site with transneural spread. Only four of 20 affected eyes retained useful vision. Poor ocular bioavailability, retinal ischemia, acquired drug resistance, and strain pathogenicity may underlie treatment failure. Acyclovir therapy appears relatively ineffective. Combined intravenous and intravitreal therapy with foscarnet and ganciclovir may be the best current management. Research advances are needed urgently. 相似文献
969.
A theoretical analysis of the temporal frequency response of multi-phase segmented k-space phase-contrast was developed. This includes the effects of both segment duration and the number of cardiac phases that are reconstructed. An increase in the number of views per segment and the corresponding increase in segment duration results in an increased smoothing or low-pass filtering of the time-resolved flow waveform. Reconstruction of all intermediate cardiac phases makes the Nyquist sampling frequency independent of the number of views per segment. This analysis was verified experimentally using a multi-phase phase-contrast segmented k-space MR pulse sequence. This sequence reconstructs all intermediate cardiac phases and uses fractional segments at the end of the cardiac cycle if an entire segment does not fit. The use of fractional segments increases the portion of the cardiac cycle over which data are acquired. 相似文献
970.
G Madico TC Quinn A Rompalo KT McKee CA Gaydos 《Canadian Metallurgical Quarterly》1998,36(11):3205-3210
Trichomonas vaginalis infection is the most prevalent nonviral sexually transmitted disease (STD) in the world. A PCR test using vaginal swab samples for the detection of T. vaginalis was developed to add T. vaginalis infection to the growing list of STDs that can be detected by DNA amplification techniques. A primer set, BTUB 9/2, was designed to target a well-conserved region in the beta-tubulin genes of T. vaginalis. All strains (15 of 15) of T. vaginalis tested were successfully detected by PCR giving a single predicted product of 112 bp in gel electrophoresis. No such targeted product was amplified with DNA from Trichomonas tenax, Trichomonas gallinae, Chlamydia trachomatis, Neisseria gonorrhoeae, Giardia lamblia, Chilomastix sulcatus, Dientamoeba fragilis, and Entamoeba histolytica. An optimal analytical sensitivity of one T. vaginalis organism per PCR was achieved. Culture, performed with the Inpouch TV culture system, was examined daily with a light microscope to identify T. vaginalis. Twenty-three of 350 (6.6%) vaginal swab samples from women attending an army medical clinic were culture positive for T. vaginalis. Of these culture positive specimens, PCR detected 22 of 23 (96%) with primer set BTUB 9/2, and wet preparation detected only 12 of 23 (52%). Seventeen specimens were BTUB 9/2-PCR positive and culture negative. Ten of these discordant specimens were determined to be as true positive by PCR using primer sets TVA 5-1/6 and/or AP65 A/B, which target different regions in the T. vaginalis genome, and seven were determined to be false positive. The sensitivity of BTUB 9/2-PCR was 97% and the specificity was 98%. The sensitivities of culture and wet preparation were 70 and 36%, respectively. The diagnosis of T. vaginalis infection by PCR is a sensitive and specific method that could be incorporated into a joint strategy for the screening of multiple STDs by using molecular amplification methods. 相似文献