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This study re-explored the nature of verbal short-term memory (STM) deficits in children with specific language impairment (SLI), by distinguishing item and serial order STM processes. Recent studies have shown serial order STM capacity to be a critical determinant of language development, relative to item STM. In Experiment 1, 12 children with SLI, 12 age-matched children and 12 language-matched children were administered serial order recognition and reconstruction tasks. Experiment 2 assessed implicit serial learning abilities via a Hebb learning task. The SLI group showed impaired performance for the serial order reconstruction and recognition tasks, relative to language-matched and/or age-matched control groups. However, normal serial position effects were observed in all SLI children in the serial order reconstruction task, suggesting normal coding of serial position information. Similarly, performance on the Hebb serial learning task was at chronological age appropriate levels. Experiment 3 showed that the group differences observed for the serial order STM tasks in Experiment 1 disappeared when the SLI group was compared to a mental age-matched control group. Experiment 4 showed similar performance levels in the SLI group and the mental age-matched control group for a nonword recognition task assessing item STM capacities. This study shows that children with SLI have no specific impairments for serial order and item STM components but that poorer general cognitive efficiency is related to functional limitations in verbal STM tasks. The data are in line with limited information processing accounts of SLI.  相似文献   
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The p-aminobenzoic acid (PABA) test has been successfully used as an indicator of completeness of 24-h urine collection in field studies of the general population. Our study was designed to investigate its validity for elderly people. Urinary excretion of fractionated oral doses of PABA was measured in 21 young control subjects (19-39 yr old) and 356 elderly (60-89 yr old) men and women. PABA excretion over 24 h was lower in elderly than in control subjects. Subjects aged greater than or equal to 70 yr had a lower recovery of the PABA dose than subjects aged 60-69 yr over the first 24 h, followed by a higher recovery over the next 24-48 h. The cumulative 48-h recovery was similar in all age classes of elderly subjects. However, 48% of the elderly subjects had a cumulative PABA recovery below the conventional cutoff for completeness (85%). These subjects also had consistently lower creatinine output and urinary volume. The lower 24-h urinary PABA recovery over 70 yr of age is interpreted to reflect the delayed renal clearance of the marker substance and indicates that the PABA test is unsuitable for this age group. The low 48-h cumulative recoveries found in all age classes of the elderly are thought to be caused by small unreported losses, which are recurrent in free-living populations.  相似文献   
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用体外培养的人的伪表皮作为模型,进行药物毒理学作用的研究,观察了二甲亚砜(DMSO)在不同浓度和不同接触时间条件下,对人的伪表皮细胞脱氧核糖核酸(DNA)、核糖核酸(RNA)和蛋白质合成的影响:随着接触时间的延长,DNA、RNA和蛋白质合成均受抑制。低浓度条件下(1%),DNA、RNA和蛋白质合成增加;在15~50%浓度下,DNA和蛋白质合成抑制,而RNA合成仍增加;在高浓度条件下(70%~100%),DNA、RNA和蛋白质合成均明显抑制。  相似文献   
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A new modified steroid esterified with the cytotoxic moiety, p-[N,N-bis(2-chloroethyl)amino]phenyl-acetic acid, has been synthesized and tested for interaction with estrogen receptor and cytotoxic activity on the MCF-7 cell line.  相似文献   
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Eighty two patients diagnosed of the Wolff-Parkinson-White syndrome (WPW) underwent operation for the surgical section of the Kent-His bundle. In these cases, posteroseptal localization (PS) occurred in 32, left lateral (LL) in 25, right lateral (RL) in six, anteroseptal (AS) in one, posteroseptal and left lateral in 14, right and left posteroseptal in two, anteroseptal and left lateral in one, and left lateral and right and left posteroseptal in one. All of the patients presented an invalidating clinical of palpitations and/or loss of consciousness, and episodes of atrial fibrillation and/or reciprocal rhythm were registered in all cases. The mean anterograde refractory period in the accessory pathways was 244 +/- 60 msec, and the shortest RR in atrial fibrillation was 190 +/- 36 msec. A mitral commissurotomy was carried out in 3 patients during surgery, mitral prostheses were implanted in two, a double aorto-coronary bypass was made in three and an interventricular communication was closed in one. After a follow-up of 36 +/- 18 months, the surgical section of the Kent bundle was found to be effective in 77 out 82 patients (94%). (In 70 out of 77 cases, both anterograde and retrograde conduction were totally abolished and in seven out of 77 obtunded. All patients were asymptomatic during the follow-up period). In 5 out of 82 patients, surgical treatment was ineffective all five showed a PS Kent-His and two presented a second Kent-His fascicle (LL).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
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Cow's milk has been shown to contain a protein complex which is able to bind vitamin K1 in a reversible manner. This binding property has been investigated by the celite method which consists in creating a dynamic equilibrium between the adsorbent, the celite and the protein complex for the ligand (vitamin K1). Based on competition experiment, the binding is specific and the vitamin K1 binding protein complex has a molecular weight equal to or higher than 7.5 X 10(2) KD.  相似文献   
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