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排序方式: 共有179条查询结果,搜索用时 15 毫秒
1.
Sekharapillae Harikumar Koduvayoor G. Padmanabhan Puthanvettil A. John Koenraad Kortmulder 《Environmental Biology of Fishes》1994,39(2):129-136
Synopsis A population of the S. Indian cyprinid fishBarbus melanampyx was sampled monthly through 24 months. Seasonal cycles of the gonado-somatic index (GSI), ovarian stages, male breeding tubercles, spawning behaviour and population structure were assessed. These fish breed strictly seasonally during the main dry period: December/January through April. Comparison with other Barbus species of the same general region led to the conclusion that the patterns of reproductive investment ofB. melanampyx are similar to those of perennial species, and different from those of wet-season spawners. The reasons for this rather unexpected result were found in the more constant conditions prevailing during a dry season as compared to the monsoon. It was argued thatB. melanampyx and the species spawning perennially are in effect small-brood spawners, rather than partial spawners. 相似文献
2.
The sociobiological fashion has for a long time discouraged the development of theories of the immediate causation of behaviour. It is only recently that new approaches are being developed to improve on the classical ethological theory originated by Lorenz and Tinbergen. One new departure is behavioural field theory (BFT) which brings back the concept of energy in behaviour, without being susceptible to the drawbacks of the energy or fuel concept of classical theory. In this paper the new theory is explained in some detail and it is shown to be illuminating, predictive and testable in examples of play-like and territorial behaviour. 相似文献
3.
Brittany L. Uhlorn Robert Jackson Shuaizhi Li Shauna M. Bratton Koenraad Van Doorslaer Samuel K. Campos 《PLoS pathogens》2020,16(11)
Oncogenic human papillomaviruses (HPVs) replicate in differentiating epithelium, causing 5% of cancers worldwide. Like most other DNA viruses, HPV infection initiates after trafficking viral genome (vDNA) to host cell nuclei. Cells possess innate surveillance pathways to detect microbial components or physiological stresses often associated with microbial infections. One of these pathways, cGAS/STING, induces IRF3-dependent antiviral interferon (IFN) responses upon detection of cytosolic DNA. Virion-associated vDNA can activate cGAS/STING during initial viral entry and uncoating/trafficking, and thus cGAS/STING is an obstacle to many DNA viruses. HPV has a unique vesicular trafficking pathway compared to many other DNA viruses. As the capsid uncoats within acidic endosomal compartments, minor capsid protein L2 protrudes across vesicular membranes to facilitate transport of vDNA to the Golgi. L2/vDNA resides within the Golgi lumen until G2/M, whereupon vesicular L2/vDNA traffics along spindle microtubules, tethering to chromosomes to access daughter cell nuclei. L2/vDNA-containing vesicles likely remain intact until G1, following nuclear envelope reformation. We hypothesize that this unique vesicular trafficking protects HPV from cGAS/STING surveillance. Here, we investigate cGAS/STING responses to HPV infection. DNA transfection resulted in acute cGAS/STING activation and downstream IFN responses. In contrast, HPV infection elicited minimal cGAS/STING and IFN responses. To determine the role of vesicular trafficking in cGAS/STING evasion, we forced premature viral penetration of vesicular membranes with membrane-perturbing cationic lipids. Such treatment renders a non-infectious trafficking-defective mutant HPV infectious, yet susceptible to cGAS/STING detection. Overall, HPV evades cGAS/STING by its unique subcellular trafficking, a property that may contribute to establishment of infection. 相似文献
4.
Martijn Callens Emilie Macke Koenraad Muylaert Peter Bossier Bart Lievens Michael Waud Ellen Decaestecker 《The ISME journal》2016,10(4):911-920
The symbiotic gut microbial community is generally known to have a strong impact on the fitness of its host. Nevertheless, it is less clear how the impact of symbiotic interactions on the hosts'' fitness varies according to environmental circumstances such as changes in the diet. This study aims to get a better understanding of host–microbiota interactions under different levels of food availability. We conducted experiments with the invertebrate, experimental model organism Daphnia magna and compared growth, survival and reproduction of conventionalized symbiotic Daphnia with germ-free individuals given varying quantities of food. Our experiments revealed that the relative importance of the microbiota for the hosts'' fitness varied according to dietary conditions. The presence of the microbiota had strong positive effects on Daphnia when food was sufficient or abundant, but had weaker effects under food limitation. Our results indicate that the microbiota can be a potentially important factor in determining host responses to changes in dietary conditions. Characterization of the host-associated microbiota further showed that Aeromonas sp. was the most prevalent taxon in the digestive tract of Daphnia. 相似文献
5.
6.
V. Claes E. Devriendt J. Tournoy K. Milisen 《Tijdschrift voor gerontologie en geriatrie》2013,44(3):112-131
Introduction
Technologies for contactless monitoring are increasingly used in order to contribute to qualitative and cost-effective care for older persons. The purpose of this systematic literature review is to explore the attitudes and perceptions of older persons towards the use of systems for contactless monitoring.Methodology
Relevant studies were identified through an extensive search strategy in Medline, Embase and Cinahl for studies published between January 1990 and August 19 2012; using a reference list offered by a group of experts in this field of research and through the exploration of the reference lists of all relevant studies.Results
Nine studies with a qualitative study design and one study with a combined study design were included in this literature review. Various aspects of the attitudes, perceptions and needs of older persons as potential or actual end-users of contactless monitoring are discussed in five themes. This refers to the perceptions of older persons on the potential usefulness of contactless monitoring, the communication of information obtained through monitoring, several concerns when contactless monitoring is used and the participation and involvement of the person who is monitored. All these facets can influence the willingness of older people to accept these monitoring systems.Conclusions
This review can offer technology developers and care providers useful information to promote acceptance and successful integration of systems for contactless monitoring into daily practice by ensuring that they meet the needs, concerns and wishes of older persons as their end-users. Further exploration of the attitudes and perceptions of older people towards contactless monitoring through qualitative and quantitative research with a good methodological quality is required. 相似文献7.
Vantrappen G Devriendt K Swillen A Rommel N Vogels A Eyskens B Gewillig M Feenstra L Fryns JP 《Genetic counseling (Geneva, Switzerland)》1999,10(1):3-9
During the last 5 years, we diagnosed in Leuven 130 patients with a 22q11 deletion. The deletion was familial in 14 out of 110 index patients (12%), which is significantly less compared to previous studies. In 10 patients, the deletion was maternal, in 4 patients paternal. A cardiac defect was the main presenting symptom in 49% of patients. The other patients were ascertained through developmental delay (16%), behavioural disturbances (7%), otorhinolaryngological manifestations (6%), psychiatric manifestations (3%) and mental retardation (2%). In one patient hypocalcemia was the presenting symptom. In another patient the severe immune deficiency led to diagnosis. Most patients presented a wide variety of the classical features of the Velo-Cardio-Facial syndrome. Velopharyngeal incompetence, learning difficulties or mostly mild mental retardation were almost always present, whereas clinical significant hypocalcemia or immune disturbances were rare. Previously un(der)recognised features include polyhydramnios, renal malformations and laryngotracheamalacia or laryngeal stenosis. 相似文献
8.
Delineation of the critical deletion region for congenital heart defects, on chromosome 8p23.1 下载免费PDF全文
Devriendt K Matthijs G Van Dael R Gewillig M Eyskens B Hjalgrim H Dolmer B McGaughran J Bröndum-Nielsen K Marynen P Fryns JP Vermeesch JR 《American journal of human genetics》1999,64(4):1119-1126
Deletions in the distal region of chromosome 8p (del8p) are associated with congenital heart malformations. Other major manifestations include microcephaly, intrauterine growth retardation, mental retardation, and a characteristic hyperactive, impulsive behavior. We studied genotype-phenotype correlations in nine unrelated patients with a de novo del8p, by using the combination of classic cytogenetics, FISH, and the analysis of polymorphic DNA markers. With the exception of one large terminal deletion, all deletions were interstitial. In five patients, a commonly deleted region of approximately 6 Mb was present, with breakpoints clustering in the same regions. One patient without a heart defect or microcephaly but with mild mental retardation and characteristic behavior had a smaller deletion within this commonly deleted region. Two patients without a heart defect had a more proximal interstitial deletion that did not overlap with the commonly deleted region. Taken together, these data allowed us to define the critical deletion regions for the major features of a del8p. 相似文献
9.
Hamdi M Van Landuyt K Monstrey S Blondeel P 《Plastic and reconstructive surgery》2004,113(4):1175-1183
Traditional skin free flaps, such as radial arm, lateral arm, and scapular flaps, are rarely sufficient to cover large skin defects of the upper extremity because of the limitation of primary closure at the donor site. Muscle or musculocutaneous flaps have been used more for these defects. However, they preclude a sacrifice of a large amount of muscle tissue with the subsequent donor-site morbidity. Perforator or combined flaps are better alternatives to cover large defects. The use of a muscle as part of a combined flap is limited to very specific indications, and the amount of muscle required is restricted to the minimum to decrease the donor-site morbidity. The authors present a series of 12 patients with extensive defects of the upper extremity who were treated between December of 1999 and March of 2002. The mean defect was 21 x 11 cm in size. Perforator flaps (five thoracodorsal artery perforator flaps and four deep inferior epigastric perforator flaps) were used in seven patients. Combined flaps, which were a combination of two different types of tissue based on a single pedicle, were needed in five patients (scapular skin flap with a thoracodorsal artery perforator flap in one patient and a thoracodorsal artery perforator flap with a split latissimus dorsi muscle in four patients). In one case, immediate surgical defatting of a deep inferior epigastric perforator flap on a wrist was performed to immediately achieve thin coverage. The average operative time was 5 hours 20 minutes (range, 3 to 7 hours). All but one flap, in which the cutaneous part of a combined flap necrosed because of a postoperative hematoma, survived completely. Adequate coverage and complete wound healing were obtained in all cases. Perforator flaps can be used successfully to cover a large defect in an extremity with minimal donor-site morbidity. Combined flaps provide a large amount of tissue, a wide range of mobility, and easy shaping, modeling, and defatting. 相似文献
10.
Dimitrov B Devriendt K Maas NM Vermeesch JR Zahariev D Avdjieva D Popova A Popova DA Fryns JP Simeonov E 《Genetic counseling (Geneva, Switzerland)》2004,15(2):191-197
Mesomelic form of chondrodysplasia and congenital glaucoma associated with de novo translocation (13;18)(q14:q23): Mesomelic dysplasias are characterized by limb shortening most prominent of the middle segment of the extremities (forearm and lower leg). In addition to several syndromic forms a few patients with sporadic or familial forms and without precise nosological classification have been reported so far. In this report we present a young female with disproportionate mesomelic dwarfism, dysmorphic facial features, bilateral glaucoma, patent ductus arteriosus, low and hoarse voice, and generalized muscular hypotonia. At the age of 2.5 years mental development is normal. High resolution G-banded chromosome studies revealed a de novo reciprocal translocation with karyotype 46,XX t (13;18)(q14;q23). The concurrence of this de novo autosomal translocation with this distinct phenotype supports the hypothesis that disruption of (a) gene(s) at the translocation breakpoints causes this unusual, apparently new form of skeletal chondrodysplasia. 相似文献