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排序方式: 共有6786条查询结果,搜索用时 15 毫秒
1.
Ava Kwong Cecilia Y. S. Ho Vivian Y. Shin Chun Hang Au Tsun Leung Chan Edmond S. K. Ma 《International journal of molecular sciences》2021,22(2)
The germline carrier of the BRCA1 pathogenic mutation has been well proven to confer an increased risk of breast and ovarian cancer. Despite BRCA1 biallelic pathogenic mutations being extremely rare, they have been reported to be embryonically lethal or to cause Fanconi anemia (FA). Here we describe a patient who was a 48-year-old female identified with biallelic pathogenic mutations of the BRCA1 gene, with no or very subtle FA-features. She was diagnosed with ovarian cancer and breast cancer at the ages of 43 and 44 and had a strong family history of breast and gynecological cancers. 相似文献
2.
Biyun Fang Chuanfeng Zhang Zeliang Qi Chunyan Li Jun Ni Xiuyun Wang Jianxin Lin Chak-Tong Au Bingyu Lin Lilong Jiang 《American Institute of Chemical Engineers》2022,68(11):e17849
The design of an efficient non-noble metal catalyst is of burgeoning interest for ammonia synthesis. Herein, we report a Mo2C/CeO2 catalyst that is superior in ammonia synthesis activity. In this catalyst, molybdenum carbide coexisted with the ceria overlayers which is from the ceria support as the strong metal–support interaction. There is a high proportion of low-valent Mo species, as well as high concentration of Ce3+ and surface oxygen species. The presence of Mo2C and CeO2 overlayers not only leads to enhancement of hydrogen and nitrogen adsorption, but also facilitates the desorption and exchange of adsorbed species with the gaseous reagents. Compared with the Mo/CeO2 catalyst prepared without carbonization, the Mo2C/CeO2 catalyst is more than sevenfold higher in ammonia synthesis rate. This work not only presents an explicit example of designing Mo-based catalyst that is highly efficient for ammonia synthesis by tuning the adsorption and desorption properties of the reactant gases, but opens a perspective for other elements in ammonia synthesis. 相似文献
3.
BF Habbick JL Nanson RE Snyder RE Casey AL Schulman 《Canadian Metallurgical Quarterly》1996,87(3):204-207
Ethers and thioethers of monosaccharides have been synthesised which show potent toxicity to mouse (LD50 > or = 4 g.kg-1 O.W. and 0.2 to 1.5 g.kg-1 I.P.W.). A study of calcium antagonist activity for the full series of compounds indicated that the activity was similar for both O- and S- ethers and maximum activities were observed for monoacetoneglucose ethers possessing carbon chain close to 8 carbons. 相似文献
4.
5.
Event-related desynchronization (ERD) was studied in 10 young (mean age = 19.1) and 10 older (mean age = 62.8) subjects during a verbal recognition task. The attention load of the task varied according to the difficulty of discriminating between targets and distractors. EEG recorded from 29 electrodes was used to compute ERD from 14 source derivations in 125 ms intervals. Thereafter, it was displayed as spatiotemporal maps. The results show that attention influences the characteristics of EEG desynchronization. In young subjects, ERD is more pronounced and more widespread when the attentional load is high. In the elderly, differences between the two attention conditions are less marked. ANOVA reveals main effects of attention and time. The significant 'attention x time x age group' interaction confirms the presence of different brain activation patterns in the two age groups in relation to attention load. 相似文献
6.
JJ Jiménez-Nácher N de Alonso B Vega A del Río JL Moya V Barrios A Hurtado 《Canadian Metallurgical Quarterly》1993,193(6):290-292
Pericardial effusion (PE) as a hypothyroidism associated sign, is something that can be found with relative frequency; nevertheless, cardiac tamponade (CT) as the first sign of this disease may be considered exceptional especially in young patients. We report a 31 years old woman with clinical symptoms and signs of CT that in the forward workshop was diagnosed of primary hypothyroidism as cause of the CT. We shortly describe the case and review the literature, emphasizing the importance of the knowledge of CT trigger factors in myxedematous PE, as well as its usual benign evolution with hormonal treatment, without recurrences of the CT after pericardiocentesis is performed. This justify a conservative approach, in spite of the slow resolution of the PE what can take as long as 1.5 years. 相似文献
7.
JM Rodríguez J Arias Díaz C García Carreras J Torres Melero JL Balibrea 《Canadian Metallurgical Quarterly》1994,9(5):304-310
Reaction of bacterial adhesins with complementary receptors on the surfaces of mucosal respiratory, gastrointestinal and genitourinary cells leads to bacterial adhesion to the human body. This is the first step in the sequence of events leading to infection. It has been observed that subinhibitory concentrations (sub-MICs) of some antibiotics are able to reduce bacterial adhesion. The pharmacokinetic curves of antibiotics show that these sub-MICs are present in tissues during a typical course of therapy. This study investigated the ability of sub-MICs of seven macrolides and four fluoroquinolones to reduce adhesiveness of Staphylococcus aureus to human buccal cells. The literature generally reports data for only one antibiotic at a time. To obtain an overall view of the findings of eleven antibiotics together, the data have been normalized according to the molecular weight of each antibiotic and the dose-effect curves determined. 相似文献
8.
QY Liu AE Schaffner YH Chang K Vaszil JL Barker 《Canadian Metallurgical Quarterly》1997,33(6):848-864
Embryonic rat hippocampal neurons were cultured in a serum-free defined medium (MEM/N3) either directly on poly-D-lysine (PDL) or on a confluent monolayer of postnatal cortical astrocytes, C6 glioma cells, or Rat2 fibroblasts. Neurons on PDL were grown in MEM/N3 or in MEM/N3 conditioned for 24 h by astrocytes or C6 cells. Membrane capacitance (Cm) and gamma-aminobutyric acid (GABA)-, glycine-, kainate-, and N-methyl-D-aspartate (NMDA)-induced currents were quantified using whole-cell patch-clamp recordings. Cm as well as the amplitude and the density of these currents in neurons cultured on astrocytes were significantly greater than those in neurons grown on PDL after 24 and 48 h. C6 cells mimicked astrocytes in promoting Cm and GABA-, glycine-, and NMDA-evoked, but not kainate-evoked, currents. Cm and currents in neurons grown on Rat2 cells were comparable to those in neurons on PDL. Astrocytes maintained in culture for 3 months were noticeably less effective than freshly prepared ones just grown to confluence. Suppression of spontaneous cytoplasmic Ca2+ (Ca[c]2+) elevations in astrocytes by 1,2-bis(2-aminophenoxy) ehane-N, N, N, N-tetraacetic acid acetoxymethyl ester (BAPTA-AM) loaded intracellularly blocked the observed modulatory effects. Medium conditioned by either astrocytes or C6 cells mimicked the effects of direct coculture of neurons on these cells in promoting Cm and amino acid-evoked currents. Inclusion of antagonists at GABA and glutamate receptors in coculture experiments blocked the observed effects. Thus, diffusible substances synthesized and/ or secreted by astrocytes in a Ca(c)2+-dependent manner can regulate neuronal growth and aminoacid receptor function, and these effects may involve neuronal GABA and glutamate receptors. 相似文献
9.
10.
MG McInnis A Chakravarti J Blaschak MB Petersen V Sharma D Avramopoulos JL Blouin U K?nig C Brahe TC Matise 《Canadian Metallurgical Quarterly》1993,16(3):562-571
A genetic linkage map of human chromosome 21q (HC21q) containing 43 markers genotyped by the polymerase chain reaction in the CEPH pedigrees is presented. The markers placed on this map are highly polymorphic with an average heterozygosity of 61%. The average interval size of the markers localized at 1000:1 odds is 2.5 cM. The map has a total length of 65.5 cM, with male and female lengths of 47.7 and 83.3 cM, respectively. The genotypes used in the construction of this map were subjected to rigorous error checking, which is reflected in the shorter map length compared to previous maps; the estimated error rate in genotyping is less than 0.04%. As noted in previous linkage maps there is increased recombination in females on proximal HC 21q and in the male in a region near the telomere. This map of HC 21 represents a highly informative and dense meiotic linkage map and will be useful in linking disease phenotypes to loci on this chromosome. 相似文献