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排序方式: 共有1371条查询结果,搜索用时 453 毫秒
81.
Michael H Holzscheiter Niels Bassler Nzhde Agazaryan Gerd Beyer Ewart Blackmore John J DeMarco Michael Doser Ralph E Durand Oliver Hartley Keisuke S Iwamoto Helge V Knudsen Rolf Landua Carl Maggiore William H McBride S?ren Pape M?ller J?rgen Petersen Lloyd D Skarsgard James B Smathers Timothy D Solberg Ulrik I Uggerh?j Sanja Vranjes H Rodney Withers Michelle Wong Bradly G Wouters 《Radiotherapy and oncology》2006,81(3):233-242
BACKGROUND AND PURPOSE: Antiprotons travel through tissue in a manner similar to that for protons until they reach the end of their range where they annihilate and deposit additional energy. This makes them potentially interesting for radiotherapy. The aim of this study was to conduct the first ever measurements of the biological effectiveness of antiprotons. MATERIALS AND METHODS: V79 cells were suspended in a semi-solid matrix and irradiated with 46.7MeV antiprotons, 48MeV protons, or (60)Co gamma-rays. Clonogenic survival was determined as a function of depth along the particle beams. Dose and particle fluence response relationships were constructed from data in the plateau and Bragg peak regions of the beams and used to assess the biological effectiveness. RESULTS: Due to uncertainties in antiproton dosimetry we defined a new term, called the biologically effective dose ratio (BEDR), which compares the response in a minimally spread out Bragg peak (SOBP) to that in the plateau as a function of particle fluence. This value was approximately 3.75 times larger for antiprotons than for protons. This increase arises due to the increased dose deposited in the Bragg peak by annihilation and because this dose has a higher relative biological effectiveness (RBE). CONCLUSION: We have produced the first measurements of the biological consequences of antiproton irradiation. These data substantiate theoretical predictions of the biological effects of antiproton annihilation within the Bragg peak, and suggest antiprotons warrant further investigation. 相似文献
82.
BACKGROUND: Postoperative nausea and vomiting (PONV) are frequent side effects of general anesthesia in children. The aim of this study was to compare the effectiveness of laser acupuncture with metoclopramide in prevention of PONV in children after sevoflurane anesthesia. METHODS: A total of 120 children ASA I and II, scheduled for hernia repair, circumcision or orchidopexy were randomly assigned into three groups: group I, received laser acupuncture on P6 point and saline infusion; group II, metoclopramide 0.1 mg.kg(-1) i.v. and sham laser; group III had sham laser and saline infusion. Anesthesia was maintained with sevoflurane and N(2)O/O(2). Patients were monitored for any symptoms of retching and vomiting at 2, 6 and 24 h postoperatively. RESULTS: The incidence of vomiting was higher in the control group in the first 2 h postoperatively (P < 0.001), compared with the other groups. There was no statistically significant difference between acupuncture and metoclopramide groups in occurrence and timing of vomiting (P < 0.001). CONCLUSION: Laser acupuncture is equally effective as metoclopramide in preventing PONV in children. 相似文献
83.
84.
Aine CJ Adair JC Knoefel JE Hudson D Qualls C Kovacevic S Woodruff CC Cobb W Padilla D Lee RR Stephen JM 《Brain research. Cognitive brain research》2005,24(1):1-18
Auditory response profiles for a group of ten healthy young and ten healthy elderly subjects, evoked by implicit memory and delayed verbal recognition tasks, were evaluated to determine if effects of stimulus repetition could be identified in the superior temporal gyrus (STG) and prefrontal cortical regions. We hypothesized that effects of stimulus repetition should occur both early in time and at early levels of the nervous system (STG) followed by later effects in prefrontal regions. Magnetoencephalographic (MEG) responses were recorded using a whole-head MEG system and automated, multi-start analysis methods were applied to the data in order to characterize the temporal response profiles from distributed but focal, cortical regions engaged in memory-related tasks. The findings revealed a main effect of age for early activity ( approximately 50 ms) in STG which appeared to be nonspecific for Old/New words and an Age x Task interaction for late activity ( approximately 100-800 ms) in STG which was specific to Old/New words. Although the behavioral performance measures did not reveal traditional effects of response priming, the MEG measures did reveal a reduction in amplitude with stimulus repetition in young subjects. The elderly did not reveal a reduction in amplitude concomitant with stimulus repetition for either the global attributes of words or for specific Old/New words. Long duration effects of stimulus repetition noted in the present study raise the possibility that results from sensory gating, mismatch negativity and P300 paradigms may represent a continuum of stimulus repetition effects. Two of these paradigms evoke greater enhancement to novel or infrequent stimuli, or rather, greater reduction of amplitude with repetition. 相似文献
85.
Agius M Biocina SM Alptekin K Rotstein V Morselli P Persaud A 《Psychiatria Danubina》2005,17(3-4):205-220
At least 95% of mental health problems are dealt with entirely in primary care. The other 5% are referred to secondary care, but these will be dealt with jointly by primary care services and secondary care services. Mental Health problems provide a major burden to primary care services, the doctors who operate in those services- the General Practitioners-, and their staff Standards need to be set in order to clarify what an adequate primary care response should be to the provision of mental health care. We propose a set of standards which are evidence based and which are correlated with the recent WHO declaration on Mental Health in Europe. 相似文献
86.
87.
88.
The aim of this study was to investigate the relation between laterality and spine deformities in early adolescence, with special reference to sex differences. Interviews, anthropometric measurements and clinical examinations of body posture were carried out on a sample of 2546 schoolchildren, aged from 11 to 14 years, in seven elementary schools in the centre of Belgrade. Possible confounding factors (age, sex, body weight and body height) were controlled for. The overall prevalence of spine deformities (scoliosis and/or thoracic hyperkyphosis) in the investigated population was 11.8%, out of which there were 7.8% adolescents with scoliosis, 4.0% with thoracic hyperkyphosis, and 0.3% with both spine deformities. The prevalence of scoliosis was 2.7 times higher in girls compared to boys (11.7% vs. 4.3%) while the prevalence of thoracic hyperkyphosis was 1,6 higher among boys (5.0% vs. 3.2%). We found 7.6% of the schoolchildren examined to be left-handed. Left handedness was significantly related to scoliosis in girls (crude OR=1.60 and 95% confidence interval=1.01–2.54). Multivariate analysis showed that significant independent factors for scoliosis were female sex (p < 0.001), age (p=0.01) and left handedness (p=0.02). We did not find any appreciable relation between left handedness and thoracic hyperkyphosis in both sexes. 相似文献
89.
Three-dimensional ultrasonographic ovarian measurements and in vitro fertilization outcome are related to age 总被引:29,自引:0,他引:29
OBJECTIVE: To evaluate whether the number of ovarian antral follicles, ovarian volume, and ovarian stromal blood flow change with age and to prospectively analyze whether three-dimensional ultrasonographic measurements predict ovarian response and IVF outcome. DESIGN: Prospective analysis. SETTING: Assisted reproductive unit. PATIENT(S): Fifty-six consecutive women 22 to 43 years of age with normal basal serum FSH concentrations who were undergoing their first IVF cycle. MAIN OUTCOME MEASURE(S): Number of ovarian antral follicles, ovarian volume, and ovarian stromal flow index were determined by three-dimensional and power Doppler ultrasonography. Pretreatment measurements were compared with number of recovered oocytes, fertilization rates, and pregnancy rates. RESULT(S): As patient age increased, significant trends in ovarian volume, number of follicles, and stromal vascularity decreased. Three-dimensional ovarian measurements and fertilization rates differed significantly among age groups. For each age group, a higher number of antral follicles, greater ovarian volume, and favorable ovarian stromal vascularity was associated with higher number of retrieved oocytes and increased pregnancy rates. CONCLUSION(S): Increasing patient age is associated with poor ovarian response, as represented by smaller ovarian volume, lower antral follicle count, and poor stromal vascularity. Three-dimensional power Doppler ultrasonography can help to individualize IVF in patients regardless of age. 相似文献
90.
Selak S Mahler M Miyachi K Fritzler ML Fritzler MJ 《Clinical immunology (Orlando, Fla.)》2003,109(2):154-164
Early endosome antigen 1 (EEA1) is a target autoantigen in patients diagnosed with neurological and other autoimmune conditions. Eighteen of 65 sera (28%) that displayed a vesicular cytoplasmic staining pattern also immunoprecipitated the recombinant EEA1. These 18 sera were selected for further clinical, serological and epitope mapping studies. Thirty-six percent of the 18 patients had neurological diseases. Seventeen sera (94%) reacted with the partial length EEA1 constructs that included the C-terminal zinc finger (+FYVE) and the methyl accepting domain (LeuMA: amino acids 82-1411) in an addressable laser bead assay suggesting that the assay may be used for rapid laboratory detection of anti-EEA1 antibodies. Three of seven sera selected for epitope mapping studies bound to EEA1 peptides represented by amino acids 1096-1125, and two reacted with peptides represented by amino acids 1296-1320. One serum reacted only with the C-terminal peptide 1096-1125. The remaining serum reacted with other EEA1 epitopes. This data was supported by the observations that all the sera immunoprecipitated the C-terminal +FYVE (EEA1 1064-1411) construct, a peptide that also contained the linear epitopes 1096-1140. The limited epitope mapping studies suggest that the sera from patients with non-neurological diseases recognized epitopes in the central and C-terminal EEA1 domains, whereas the patients with neurological disease recognized a more restricted set of epitopes in the C-terminal. 相似文献