首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The study is a critical analysis of the decisions to induce labour or schedule cesareans in the practice of a third level referral centre, with as outcome criterion the reduction of fetal death. 783 women pregnant with twins were included from 1.1.1993 to 31.12.1998, in three groups: originally booked, referred for care during pregnancy, or transferred from another institution. The results show that an important proportion of preterm deliveries result from a medical decision to induce labour or from a scheduled cesarean in the originally booked group with even higher proportions in groups of referred and transferred women. These results are discussed in relation to fetal death rates and causes. Deaths related to fetal growth restriction were not observed in women originally booked for care. The hospital bias has been discussed. The conclusion is that decisions to minimize fetal deaths in twin pregnancies increased preterm deliveries by medical decision.  相似文献   

2.
Based on detailed study of available specimens and perusal of literature, it is shown that Melanoseris lessertiana or Mulgedium lessertianum is not present in China and corresponding reports in the floristic literature of China actually refer to a species originally described as Mulgedium qinghaicum, and correctly placed as Melanoseris qinghaica, a species here reported for the first time also for Bhutan. Mqinghaica can be clearly distinguished from Mlessertiana by achene shape and anther tube length. The rare and little known Yunnan endemic, originally described as Lactuca monocephala and tentatively considered as conspecific with Mlessertiana recently, is confirmed as an independent species related to the Matropurpurea complex. Of two recently described species from N Pakistan and Kashmir morphologically allied to Mlessertiana, Cicerbita alii is confirmed as a separate species and transferred to Melanoseris, while Castorensis is considered as conspecifc with Mlessertiana.  相似文献   

3.
Fungal biocatalysts in the biofiltration of VOC-polluted air   总被引:3,自引:0,他引:3  
Gas-phase biofilters used for the treatment of waste gases were originally packed with compost or other natural filter beds containing indigenous microorganisms. Over the past decade much effort has been made to develop new carrier materials, more performant biocatalysts and new types of bioreactors. Elimination capacities reached nowadays are 5 to 10 times higher than those originally reported with conventional compost biofilters. With the recently developed inert filter beds, inoculation is a prerequisite for successful start-up and operation. Either non-defined mixed cultures or pure bacterial cultures have originally been used. The search for efficient fungal biocatalysts started only a few years ago, mainly for the biofiltration of waste gases containing hydrophobic compounds, such as styrene, alpha-pinene, benzene, or alkylbenzenes. In this review, recently isolated new fungal strains able to degrade alkylbenzenes and other related volatile organic pollutants are described, as well as their major characteristics and their use as biocatalysts in gas-phase biofilters for air pollution control. In biofiltration, the most extensively studied organism belongs to the genus Exophiala, although strains of Scedosporium, Paecilomyces, Cladosporium, Cladophialophora, and white-rot fungi are all potential candidates for use in biofilters. Encouraging results were obtained in most of the cases in which some of those organisms were present in gas-phase biofilters. They allow reaching high elimination capacities and are resistant to low pH values and to reduce moisture content.  相似文献   

4.
Revised Interpretation of the Origin of the pSC101 Plasmid   总被引:52,自引:31,他引:21       下载免费PDF全文
Data are presented indicating that the pSC101 plasmid was not derived by recircularization of a mechanically sheared fragment of R6-5 plasmid deoxyribonucleic acid, as was originally believed.  相似文献   

5.
6.
Total synthesis of both enantiomers of 9-methoxystrobilurin L as the originally proposed 1,4-benzodioxan structure was successfully achieved. The 1H and 13C NMR spectra of synthesized 9-methoxystrobilurin L were compared with those of a naturally-occurring sample. It was strongly indicated that naturally-occurring 9-methoxystrobilurin L has not the originally reported 1,4-benzodioxan structure but a 1,5-benzodioxepin structure, the same as previously reported 9-methoxystrobilurin K. Antifungal activities of the synthesized compounds toward several typical fungi were also examined, and they were less active than 9-methoxystrobilurin K.  相似文献   

7.
Reevaluation of the systematic position of Scenella   总被引:1,自引:0,他引:1  
Specimens originally illustrated from Lower Cambrian rocks of the Sierra Morena in Badajoz and Sevilla Provinces, southwestern Spain are supplemented by new material from another locality and are described as Scenella morenensis n. sp. Although Scenella was originally considered to be a patelliform gastropod, for three decades now the genus has been classified as a monoplacophoran. The type species of Scenella, S. reticulata Billings, does not show any paired muscles scars, nor does this new species; such scars are indicative of the Monoplacophora. This new species of Scenella does exhibit features which suggest assignment to the chondrophorine coelenterates. If so, Scenella cannot represent the ancestral form of mollusk.  相似文献   

8.
Molecular and Cellular Biochemistry - Obesity was originally considered a disease endemic to developed countries but has since emerged as a global health problem. Obesity is characterized by...  相似文献   

9.
Experiments with crucians (Carassius carassius L.) and goldfish (Carassius auratus L.) have shown that a consolidated memory trace of a simple visual pattern became disturbed by later seeing series of similar patterns (unrewarded), that is to say by latent learning. In a test in which the experimental group (es) had to choose between the originally learnt and the similar pattern, it did not prefer the former, whereas the control group (cs), which had only seen white walls of the aquarium, still preferred the originally learnt pattern. The same happened when es learnt a similar pattern by reward after the memory of the original pattern had been consolidated. In another set of experiments the negative influence of post-exposure could be demonstrated in facilitation of later learning the postexposed pattern as positive versus the originally learnt pattern, now negative. When es had seen a dissimilar wall-paper pattern then the memory of the primarily learnt pattern was not disturbed. A tentative explanation is based on the notion that two similar engrams have part of the neuronal network in common.  相似文献   

10.
As the eponymous type species for rauisuchians, Rauisuchus tiradentes von Huene, 1938 represents an important but inadequately known specimen. The revision of the type material from the Upper Triassic (Carnian) Santa Maria Formation of Brazil reveals new anatomical data and previously unrecognised characters, including three new possible autapomorphies: a knob‐like thickening on the base of the posterior process of the premaxilla; short and ventrally keeled cervicals lacking postzygodiapophyseal laminae; and mid‐caudal vertebrae with an accessory neural spine and a postspinal lamina. Several elements are re‐identified, including a postorbital (originally identified as postfrontal) and a pterygoid (originally identified as a prefrontal), and additional material from a secondary fossil site, originally assigned to R. tiradentes, including a left ilium, is excluded. Based on the recovered information and new morphological data, the systematic position of R. tiradentes is tested in a comparison of two phylogenetic reanalyses. Both analyses differ in respect to the phylogenetic position of R. tiradentes, and recover ‘rauisuchians’ as a paraphyletic assemblage of non‐crocodylomoprh archosaurs. © 2014 The Linnean Society of London  相似文献   

11.
从白车轴草(Trifolium repens)自然种各中采集无白车轴草单孢锈菌病史的无性系(clones)17个,有白车轴草单孢锈菌病史的无性系14个,分别作为抗病型和感受型植物实验材料;采集白车轴草单孢锈菌(Uromyces trifolii-repentis)菌系(strains)10个,作为病菌实验材料,分别设置并进行了两个温室实验、一个田间盆栽实验和一个原生长地移栽实验,实验处理上分对照、单菌系接种和10个菌系接种等3种。实验结果表明,无论是用单菌系接种还是10个菌系接种,植株发病的概率和程度均与其抗病性有关,抗病型植株(无病史)发病的概率和程度显著低于感受型(有病史)植株,在相同处理的实验中(无论是田间实验还是温室实验),无病史植株和有病史植株的生长无显著差异;不同处理田间实验植株的生长有显著差异,病情愈重,生长愈差,无病史植株的抗病性明显强于有病史植株,但是,原生长地的移栽实验结果表明,在无病原菌存在的情况下,有病史植株的(叶)生长显著好于无病史植株,可以认为,研究生物个体对环境因子反应性差异的实验应当在自然条件下和自然梯度范围内进行。  相似文献   

12.
Completed eukaryotic genomes were screened for medium-chain dehydrogenases/reductases (MDR). In the human genome, 23 MDR forms were found, a number that probably will increase, because the genome is not yet fully interpreted. Partial sequences already indicate that at least three further members exist. Within the MDR superfamily, at least eight families were distinguished. Three families are formed by dimeric alcohol dehydrogenases (ADH; originally detected in animals/plants), cinnamyl alcohol dehydrogenases (originally detected in plants) and tetrameric alcohol dehydrogenases (originally detected in yeast). Three further families are centred around forms initially detected as mitochondrial respiratory function proteins, acetyl-CoA reductases of fatty acid synthases, and leukotriene B4 dehydrogenases. The two remaining families with polyol dehydrogenases (originally detected as sorbitol dehydrogenase) and quinone reductases (originally detected as zeta-crystallin) are also distinct but with variable sequences. The most abundant families in the human genome are the dimeric ADH forms and the quinone oxidoreductases. The eukaryotic patterns are different from those of Escherichia coli. The different families were further evaluated by molecular modelling of their active sites as to geometry, hydrophobicity and volume of substrate-binding pockets. Finally, sequence patterns were derived that are diagnostic for the different families and can be used in genome annotations.  相似文献   

13.
This paper reports the biochemical properties of two types of recombinant flap endonuclease-1 (FEN-1) proteins obtained from the thermophilic crenarchaeon, Sulfolobus tokodaii strain 7. One of the two FEN-1 proteins is a product of the gene with AUG as the translational start codon (StoS-FEN-1), which is originally assigned in the database. The other is a product of the gene with a new AUG start codon (StoL-FEN-1), which is inserted at 153 bases upstream of the original AUG codon. Although StoL-FEN-1 showed activity and thermostability, StoS-FEN-1 showed neither activity nor thermostability. The N-terminal region in StoL-FEN-1 was also conserved in all of the FEN-1 homologs deduced from genes from newly isolated Sulfolobus spp. These results strongly suggest that the actual start codon of the fen-1 gene from S. tokodaii is not the originally assigned AUG, but rather is located at about 100 bases upstream of this codon.  相似文献   

14.
Grateloupia doryphora (Montagne) Howe, originally described from Peru, has repeatedly been reported as an invasive species in Atlantic and Mediterranean waters. Various attempts to explain this species' route of introduction have been unsatisfactory. New evidence from comparative rbcL sequence analysis and morphology suggests that this adventive species in the NE and NW Atlantic corresponds with G. turuturu Yamada, originally described from Japan. This provenance follows a well-recognized trend of invasive marine organisms that have colonized the Atlantic Ocean and Mediterranean Sea from Pacific NE Asia.  相似文献   

15.
Hyphomicrobium sp. strain MC1 is an aerobic methylotroph originally isolated from industrial sewage. This prosthecate bacterium was the first strain reported to grow with chloromethane as the sole carbon and energy source. Its genome, consisting of a single 4.76-Mb chromosome, is the first for a chloromethane-degrading bacterium to be formally reported.  相似文献   

16.
Schendylurus (Schendylotyn) integer Chamberlin, 1926, originally described as a member of the Schendylidae, is transferred here to the Ballophilidae as Taeniolinum integer n. comb. and redescribed after the type specimen. Taeniolinum setosum guadeloupensis Demange and Pereira, 1985 is elevated to specific rank.  相似文献   

17.
Archaeonassa is a poorly known ichnogenus, originally described from the Cambrian of North America, which is a member of the Scolicia ’group’, but can be regarded as distinct from Scolicia. Archaeonassa was originally based on modern material, and therefore falls into a taxonomic grey zone concerning its availability, but as A. fossulata was erected on fossil material the ichnogenus is here retained. Although exhibiting a degree of morphological plasticity in its style of ornament, Archaeonassa is considered to be monospecific, with only the ichnospecies A. fossulata recognised. The ichnogenus appears to be restricted to the Paleozoic, although similar material is well documented from modern environments. Thus the ichnogenus is expected to be geographically and stratigraphically more widespread than it otherwise appears. Archaeonassa is a valuable tool for environmental reconstruction within the Paleozoic as it occurs within intertidal deposits. The ichnogenus is interpreted chiefly as the work of gastropods, although in many cases may have been produced by trilobites or even echinoids, and represents the exogenic expression of either surface or shallow subsurface locomotion.  相似文献   

18.
Fine mapping versus replication in whole-genome association studies   总被引:3,自引:0,他引:3       下载免费PDF全文
Association replication studies have a poor track record and, even when successful, often claim association with different markers, alleles, and phenotypes than those reported in the primary study. It is unknown whether these outcomes reflect genuine associations or false-positive results. A greater understanding of these observations is essential for genomewide association (GWA) studies, since they have the potential to identify multiple new associations that that will require external validation. Theoretically, a repeat association with precisely the same variant in an independent sample is the gold standard for replication, but testing additional variants is commonplace in replication studies. Finding different associated SNPs within the same gene or region as that originally identified is often reported as confirmatory evidence. Here, we compare the probability of replicating a gene or region under two commonly used marker-selection strategies: an "exact" approach that involves only the originally significant markers and a "local" approach that involves both the originally significant markers and others in the same region. When a region of high intermarker linkage disequilibrium is tested to replicate an initial finding that is only weak association with disease, the local approach is a good strategy. Otherwise, the most powerful and efficient strategy for replication involves testing only the initially identified variants. Association with a marker other than that originally identified can occur frequently, even in the presence of real effects in a low-powered replication study, and instances of such association increase as the number of included variants increases. Our results provide a basis for the design and interpretation of GWA replication studies and point to the importance of a clear distinction between fine mapping and replication after GWA.  相似文献   

19.

Oklahomaichnus millsii Sarjeant, from the Pennsylvanian (Missourian) Nellie Bly Formation of Oklahoma, is not the trackway of a lepospondyl amphibian, as originally proposed. Instead, it is the undertrack of an arthropod.  相似文献   

20.
The fossil species Architipula fragmentosa (Bode) comb. nov. (Diptera: Nematocera: Limoniidae) from the German Upper Lias (Lower Jurassic) is redescribed. This species was originally described by Bode (1953) in a new monotypic genus as Eoasilidea fragmentosa and placed in the Brachycera, with Eoasilidea as the type-genus of a new family Eoasilidae. This family is here synonymized with the Limoniidae (Nematocera), and the genus Eoasilidea is synonymized with Architipula Handlirsch .  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号