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1.
Theriogenology ; 120: 105-110, 2018 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-30096616

RESUMO

The present study was conducted in cattle to test the null hypothesis that the pregnancy rate of recipient females is similar when in vitro-derived embryos are transferred either fresh (non-vitrified) or after being subjected to vitrification. Cumulus-oocyte complexes, collected twice (6 weeks apart) from 10 donor cows were matured in vitro and inseminated with frozen-thawed sperm from a single proven bull per donor collection. Cleaved embryos were cultured in vitro until day 7 and any resulting blastocysts were graded for stage [early (unexpanded), advanced (expanded, hatching, hatched)] and/or quality and either discarded (poor quality), or, if deemed suitable, transferred fresh or vitrified for later warming and transfer. All blastocysts were transferred singly to oestrus-synchronized cows and pregnancy monitored by transrectal palpation on days 35, 60 and 90. From 20 collections, 818 cumulus-oocyte complexes were aspirated; however, after grading, only 462 (56.5%) were ranked as suitable quality for maturation and insemination. From those 462 complexes inseminated, 363 (78.6%) cleaved during the process and 243 (52.6%) developed to the blastocyst stage with 194 (42.0%) deemed utilizable, of which 85 were vitrified and 109 were transferred fresh. There was a median of 13 (range 0-24) utilizable blastocysts per cow. Of the 109 non-vitrified blastocysts transferred, there were 45 (41.3%) and 41 (37.6%) recipients that were detected to be pregnant on day 35 and day 90, respectively, subsequent to transfer. Thus, an 8.9% abortion rate was observed (4/45). Of the 85 transferred vitrified-warmed blastocysts, 34 were detected to be pregnant (40.0%) on day 35 following transfer, and all pregnancies were maintained at day 90 (0% abortion rate), which was similar to non-vitrified transfers (P > 0.05, Chi-square test). There was no significant difference in pregnancy rate on day 90 in advanced compared to early blastocysts for either the non-vitrified transfers (9/23, 39.1% vs 33/86, 38.3%) or the vitrified transfers (30/72, 41.6% vs 4/13, 30.8%) (P > 0.05 in each case). In summary, these data show that vitrification of in vitro-derived early and advanced blastocysts is a suitable method of cryopreservation of bovine embryos, and, furthermore, that subsequent transfer of all vitrified/warmed blastocysts into recipient females results in pregnancy rates no different to those attained by non-vitrified transfers into recipient females.


Assuntos
Bovinos , Criopreservação/veterinária , Transferência Embrionária/veterinária , Animais , Transferência Embrionária/métodos , Feminino , Gravidez , Taxa de Gravidez , Vitrificação
2.
Cryobiology ; 77: 58-63, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28545999

RESUMO

The effectiveness of three cryopreservation protocols (slow freezing, short equilibration vitrification and long equilibration vitrification) on in vitro-derived cattle embryos at expanded blastocyst and pronuclear stages was compared. 199 expanded blastocysts of good quality were assigned randomly into four treatment groups [control, non-cryopreserved (fresh, unfrozen); and the three cryopreservation methods]. The re-expansion of the cryopreserved blastocysts after 24 h in vitro culture was similar to that of the fresh control group. However, the hatching rate of expanded blastocysts after 48 h culture was significantly less for the slow freezing group (31/47; 66.0%) than for both the short equilibration vitrification (46/51; 90.2%) and long equilibration vitrification groups (42/50; 84.0%). Denuded presumptive zygotes at the pronuclear stage (14-18 h post-insemination) were assigned randomly to the same four treatment groups and, following thawing, embryos were assessed for their capacity to cleave and to develop into a blastocyst. Overall, cleavage rates of cryopreserved zygotes were significantly less than those of the fresh control. The blastocyst formation rate of slow-frozen zygotes (4/81; 4.9%) was significantly less than that of zygotes subjected either to short equilibration vitrification (18/82; 22.0%) or long equilibration vitrification (16/74; 21.6%). All cryopreservation groups showed rates of blastocyst formation that were significantly less than that of the fresh control (51/92; 55.4%). Collectively, our findings indicate that vitrification is the preferred technology to cryopreserve in vitro-derived cattle embryos at expanded blastocyst and pronuclear stages. Moreover, short equilibration vitrification technology can improve outcomes and be more efficient by taking less time to perform.


Assuntos
Criopreservação/métodos , Embrião de Mamíferos , Animais , Bovinos , Técnicas de Cultura Embrionária , Desenvolvimento Embrionário , Congelamento , Vitrificação
3.
IEEE Comput Graph Appl ; 37(2): 31-41, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27244727

RESUMO

In many spatial and temporal visualization applications, glyphs provide an effective means for encoding multivariate data. However, because glyphs are typically small, they are vulnerable to various perceptual errors. This article introduces the concept of a quasi-Hamming distance in the context of glyph design and examines the feasibility of estimating the quasi-Hamming distance between a pair of glyphs and the minimal Hamming distance for a glyph set. The authors demonstrate the design concept by developing a file-system event visualization that can depict the activities of multiple users.

4.
BMC Public Health ; 16: 925, 2016 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-27590255

RESUMO

BACKGROUND: Smartphones are ideal for promoting physical activity in those with little intrinsic motivation for exercise. This study tested three hypotheses: H1 - receipt of social feedback generates higher step-counts than receipt of no feedback; H2 - receipt of social feedback generates higher step-counts than only receiving feedback on one's own walking; H3 - receipt of feedback on one's own walking generates higher step-counts than no feedback (H3). METHODS: A parallel group randomised controlled trial measured the impact of feedback on steps-counts. Healthy male participants (n = 165) aged 18-40 were given phones pre-installed with an app that recorded steps continuously, without the need for user activation. Participants carried these with them as their main phones for a two-week run-in and six-week trial. Randomisation was to three groups: no feedback (control); personal feedback on step-counts; group feedback comparing step-counts against those taken by others in their group. The primary outcome measure, steps per day, was assessed using longitudinal multilevel regression analysis. Control variables included attitude to physical activity and perceived barriers to physical activity. RESULTS: Fifty-five participants were allocated to each group; 152 completed the study and were included in the analysis: n = 49, no feedback; n = 53, individual feedback; n = 50, individual and social feedback. The study provided support for H1 and H3 but not H2. Receipt of either form of feedback explained 7.7 % of between-subject variability in step-count (F = 6.626, p < 0.0005). Compared to the control, the expected step-count for the individual feedback group was 60 % higher (effect on log step-count = 0.474, 95 % CI = 0.166-0.782) and that for the social feedback group, 69 % higher (effect on log step-count = 0.526, 95 % CI = 0.212-0.840). The difference between the two feedback groups (individual vs social feedback) was not statistically significant. CONCLUSIONS: Always-on smartphone apps that provide step-counts can increase physical activity in young to early-middle-aged men but the provision of social feedback has no apparent incremental impact. This approach may be particularly suitable for inactive people with low levels of physical activity; it should now be tested with this population.


Assuntos
Exercício Físico , Obesidade/prevenção & controle , Smartphone , Adolescente , Adulto , Retroalimentação Fisiológica , Humanos , Masculino , Saúde do Homem , Aplicativos Móveis , Resultado do Tratamento , Adulto Jovem
5.
IEEE Trans Vis Comput Graph ; 21(8): 980-93, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26357260

RESUMO

The existing efforts in computer assisted semen analysis have been focused on high speed imaging and automated image analysis of sperm motility. This results in a large amount of data, and it is extremely challenging for both clinical scientists and researchers to interpret, compare and correlate the multidimensional and time-varying measurements captured from video data. In this work, we use glyphs to encode a collection of numerical measurements taken at a regular interval and to summarize spatio-temporal motion characteristics using static visual representations. The design of the glyphs addresses the needs for (a) encoding some 20 variables using separable visual channels, (b) supporting scientific observation of the interrelationships between different measurements and comparison between different sperm cells and their flagella, and (c) facilitating the learning of the encoding scheme by making use of appropriate visual abstractions and metaphors. As a case study, we focus this work on video visualization for computer-aided semen analysis, which has a broad impact on both biological sciences and medical healthcare. We demonstrate that glyph-based visualization can serve as a means of external memorization of video data as well as an overview of a large set of spatiotemporal measurements. It enables domain scientists to make scientific observation in a cost-effective manner by reducing the burden of viewing videos repeatedly, while providing them with a new visual representation for conveying semen statistics.


Assuntos
Gráficos por Computador , Interpretação de Imagem Assistida por Computador/métodos , Análise do Sêmen/métodos , Gravação em Vídeo/métodos , Algoritmos , Humanos , Masculino , Análise Multivariada , Motilidade dos Espermatozoides/fisiologia , Cauda do Espermatozoide/fisiologia
6.
Prog Biophys Mol Biol ; 115(2-3): 349-58, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25091538

RESUMO

Cardiovascular Magnetic Resonance (CMR) imaging is an essential technique for measuring regional myocardial function. However, it is a time-consuming and cognitively demanding task to interpret, identify and compare various motion characteristics based on watching CMR imagery. In this work, we focus on the problems of visualising imagery resulting from 2D myocardial tagging in CMR. In particular we provide an overview of the current state of the art of relevant visualization techniques, and a discussion on why the problem is difficult from a perceptual perspective. Finally, we introduce a proof-of-concept multilayered visualization user interface for visualizing CMR data using multiple derived attributes encoded into multivariate glyphs. An initial evaluation of the system by clinicians suggested a great potential for this visualisation technology to become a clinical practice in the future.


Assuntos
Coração/anatomia & histologia , Coração/fisiologia , Interpretação de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Imagem Cinética por Ressonância Magnética/métodos , Contração Miocárdica/fisiologia , Animais , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Processamento de Sinais Assistido por Computador , Análise Espaço-Temporal , Técnica de Subtração , Interface Usuário-Computador
7.
Anim Reprod Sci ; 148(3-4): 91-6, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24998156

RESUMO

Recent advances in embryology and related research offer considerable possibilities to accelerate genetic improvement in cattle breeding. Such progress includes optimization and standardization of laboratory embryo production (in vitro fertilization - IVF), introduction of a highly efficient method for cryopreservation (vitrification), and dramatic improvement in the efficiency of somatic cell nuclear transfer (cloning) in terms of required effort, cost, and overall outcome. Handmade cloning (HMC), a simplified version of somatic cell nuclear transfer, offers the potential for relatively easy and low-cost production of clones. A potentially modified method of vitrification used at a centrally located laboratory facility could result in cloned offspring that are economically competitive with elite animals produced by more traditional means. Apart from routine legal and intellectual property issues, the main obstacle that hampers rapid uptake of these technologies by the beef cattle industry is a lack of confidence from scientific and commercial sources. Once stakeholder support is increased, the combined application of these methods makes a rapid advance toward desirable traits (rapid growth, high-quality beef, optimized reproductive performance) a realistic goal. The potential impact of these technologies on genetic advancement in beef cattle herds in which improvement of stock is sought, such as in northern Australia, is hard to overestimate.


Assuntos
Bovinos , Clonagem de Organismos/métodos , Embrião de Mamíferos , Melhoramento Genético/métodos , Vitrificação , Animais , Austrália , Bovinos/embriologia , Bovinos/genética , Clonagem de Organismos/veterinária , Criopreservação/métodos , Criopreservação/veterinária , Fertilização in vitro/métodos , Fertilização in vitro/veterinária
8.
Int J Obstet Anesth ; 12(2): 138-9, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15321505
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