514 research outputs found

    Speech Sound Status of Newborn Negro and White Infants

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    The speech sounds of 50 white and of 30 negro newborns were transcribed in the International Phonetic Alphabet. Comparisons were made between the two groups. Further comparisons were made of these two groups with older infants and with adults

    The Relation Between Mental Test Scores on Infants and Speech Development

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    Chen (1) has formulated a number of indices and ratios which are useful in determining the course of development of pre-meaningful speech. He has also formulated a differential speech development index based upon the difference between speech sounds considered as isolated elements at a given infant age level and the status of these elements in adult speech. The adult speech standard used for comparison is that by Voelker (3). There are two forms of this index described, elsewhere (2). One is the difference between the number of speech sounds elements in infants and adult speech, the second form is the differential percentage index based on the difference in the percent of frequencies in the use of vowel and consonants of infants and adults. A group of infants under 30 months were used. Intelligence test scores were secured by means of the Kuhlmann Test of Mental Development

    Oncolytic Viruses for Cancer Therapy: Overcoming the Obstacles

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    Targeted therapy of cancer using oncolytic viruses has generated much interest over the past few years in the light of the limited efficacy and side effects of standard cancer therapeutics for advanced disease. In 2006, the world witnessed the first government-approved oncolytic virus for the treatment of head and neck cancer. It has been known for many years that viruses have the ability to replicate in and lyse cancer cells. Although encouraging results have been demonstrated in vitro and in animal models, most oncolytic viruses have failed to impress in the clinical setting. The explanation is multifactorial, determined by the complex interactions between the tumor and its microenvironment, the virus, and the host immune response. This review focuses on discussion of the obstacles that oncolytic virotherapy faces and recent advances made to overcome them, with particular reference to adenoviruses

    Transposon Ac/Ds-induced chromosomal rearrangements at the rice OsRLG5 locus

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    Previous studies have shown that pairs of closely-linked Ac/Ds transposable elements can induce various chromosomal rearrangements in plant genomes. To study chromosomal rearrangements in rice, we isolated a line (OsRLG5-161) that contains two inversely-oriented Ds insertions in OsRLG5 (Oryza sativa Receptor like kinase Gene 5). Among approximately 300 plants regenerated from OsRLG5-161 heterozygous seeds, 107 contained rearrangements including deletions, duplications and inversions of various sizes. Most rearrangements were induced by previously identified alternative transposition mechanism. Furthermore, we also detected a new class of rearrangements that contain juxtaposed inversions and deletions on the same chromosome. We propose that these novel alleles were generated by a previously unreported type of alternative transposition reactions involving the 5′ and 3′ termini of two inversely-oriented Ds elements located on the same chromatid. Finally, 11% of rearrangements contained inversions resulting from homologous recombination between the two inverted Ds elements in OsRLG5-161. The high frequency inheritance and great variety of rearrangements obtained suggests that the rice regeneration system results in a burst of transposition activity and a relaxation of the controls which normally limit the transposition competence of individual Ds termini. Together, these results demonstrate a greatly enlarged potential of the Ac/Ds system for plant chromosome engineering

    Rational synthesis of an atomically precise carboncone under mild conditions

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    在已知的碳的存在形态中,还有一种锥型的碳结构,早在50年前人们在热解碳时发现了这类结构,此前也常被人们称为碳纳米锥,虽然这类碳纳米锥有望作为扫描隧道显微镜的探针、场发射头等替代材料,但始终未能找到合适方法精准地合成它们。因此,这类锥型碳材料尚未得到人们足够重视和开发。功能团簇材料创新研究群体的谢素原、张前炎课题组与美国波士顿学院的Lawrence Scott教授合作,首次通过有机合成途径,在温和的条件下合成得到了首例结构明确的碳锥单元(碳锥子)C70H20及其可溶衍生物。他们通过实验、理论计算、结构分析,最终在他们合成的碳锥子结构中,仅有1个五元环在锥顶,而在锥顶和锥缘之间(围绕着中心五元环)有2圈由六元环组成的完整的稠圈层,谢素原等将这一碳锥子命名为carboncone[1,2]。通过这一典型的碳锥子(carboncone[1,2]),有望借助气相沉积等技术不断增加稠圈层数(m)来制备具有确定锥角的系列单壁纳米碳锥(carboncone[1,m>2])。随着研究的深入,不久的将来人类有望合成出其它四种不同锥角的碳锥子(carboncone[n=2-5,m]),完整地研究探索和开发利用这类锥型结构的碳材料。 化学化工学院2015级硕士生朱正钟(主要负责合成)和2017级博士生陈佐长(主要负责理论计算)为该论文的共同第一作者。Carboncones, a special family of all-carbon allotropes, are predicted to have unique properties that distinguish them from fullerenes, carbon nanotubes, and graphenes. Owing to the absence of methods to synthesize atomically well-defined carboncones, however, experimental insight into the nature of pure carboncones has been inaccessible. Herein, we describe a facile synthesis of an atomically well-defined carboncone[1,2] (C70H20) and its soluble penta-mesityl derivative. Identified by x-ray crystallography, the carbon skeleton is a carboncone with the largest possible apex angle. Much of the structural strain is overcome in the final step of converting the bowl-shaped precursor into the rigid carboncone under mild reaction conditions. This work provides a research opportunity for investigations of atomically precise single-layered carboncones having even higher cone walls and/or smaller apex angles.This research was supported by the National Natural Science Foundation of China (21771152, 21721001, 21390390, 21827801, 51572231, 21571151, and 21701134), the 973 Program of China (2015CB932301), the Major Science and Technology Project between University-Industry Cooperation in Fujian Province (2016H6023), and the Fundamental Research Funds for the Central Universities (20720170028 and 20720160084). This research was also supported financially by the U.S. National Science Foundation (CHE-0809494 and CHE-1149096). 研究工作得到国家自然科学基金(21771152等)、科技部重大科学研究计划项目(2015CB932301)和福建省高校产学合作项目、中央高校基本科研业务费、美国国家科学基金等的资助
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