Brief inactivation of c-Myc is not sufficient for sustained regression of c-Myc-induced tumours of pancreatic islets and skin epidermis

Background Tumour regression observed in many conditional mouse models following oncogene inactivation provides the impetus to develop, and a platform to preclinically evaluate, novel therapeutics to inactivate specific oncogenes. Inactivating single oncogenes, such as c-Myc, can reverse even advanced tumours. Intriguingly, transient c-Myc inactivation proved sufficient for sustained osteosarcoma regression; the resulting osteocyte differentiation potentially explaining loss of c-Myc's oncogenic properties. But would this apply to other tumours? Results We show that brief inactivation of c-Myc does not sustain tumour regression in two distinct tissue types; tumour cells in pancreatic islets and skin epidermis continue to avoid apoptosis after c-Myc reactivation, by virtue of Bcl-xL over-expression or a favourable microenvironment, respectively. Moreover, tumours progress despite reacquiring a differentiated phenotype and partial loss of vasculature during c-Myc inactivation. Interestingly, reactivating c-Myc in β-cell tumours appears to result not only in further growth of the tumour, but also re-expansion of the accompanying angiogenesis and more pronounced β-cell invasion (adenocarcinoma). Conclusions Given that transient c-Myc inactivation could under some circumstances produce sustained tumour regression, the possible application of this potentially less toxic strategy in treating other tumours has been suggested. We show that brief inactivation of c-Myc fails to sustain tumour regression in two distinct models of tumourigenesis: pancreatic islets and skin epidermis. These findings challenge the potential for cancer therapies aimed at transient oncogene inactivation, at least under those circumstances where tumour cell differentiation and alteration of epigenetic context fail to reinstate apoptosis. Together, these results suggest that treatment schedules will need to be informed by knowledge of the molecular basis and environmental context of any given cancer

The greedy basis equals the theta basis

We prove the equality of two canonical bases of a rank 2 cluster algebra, the greedy basis of Lee-Li-Zelevinsky and the theta basis of Gross-Hacking-Keel-Kontsevich.Comment: 17 page

The greedy basis equals the theta basis: A rank two haiku

We prove the equality of two canonical bases of a rank 2 cluster algebra, the greedy basis of Lee–Li–Zelevinsky and the theta basis of Gross–Hacking–Keel–Kontsevich.National Science FoundationThis is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.jcta.2016.08.00

Heterologous influenza vRNA segments with identical non-coding sequences stimulate viral RNA replication in trans

The initiation of transcription and replication of influenza A virus requires the 5' and 3' ends of vRNA. Here, the role of segment-specific non-coding sequences of influenza A virus on viral RNA synthesis was studied. Recombinant viruses, with the nonstructural protein (NS) segment-specific non-coding sequences replaced by the corresponding sequences of the neuraminidase (NA) segment, were characterized. The NS and NA vRNA levels in cells infected with these mutants were much higher than those of the wild type, whereas the NS and NA mRNA levels of the mutants were comparable to the wild-type levels. By contrast, the PB2 vRNA and mRNA levels of all the tested viruses were similar, indicating that vRNA with heterologous segment-specific non-coding sequences was not affected by the mutations. The observations suggested that, with the cooperation between the homologous 5' and 3'segment-specific sequences, the introduced mutations could specifically enhance the replication of NA and NS vRNA

How to guess a gradient

How much can you say about the gradient of a neural network without computing a loss or knowing the label? This may sound like a strange question: surely the answer is "very little." However, in this paper, we show that gradients are more structured than previously thought. Gradients lie in a predictable low-dimensional subspace which depends on the network architecture and incoming features. Exploiting this structure can significantly improve gradient-free optimization schemes based on directional derivatives, which have struggled to scale beyond small networks trained on toy datasets. We study how to narrow the gap in optimization performance between methods that calculate exact gradients and those that use directional derivatives. Furthermore, we highlight new challenges in overcoming the large gap between optimizing with exact gradients and guessing the gradients

Micro-Net: A unified model for segmentation of various objects in microscopy images

Object segmentation and structure localization are important steps in automated image analysis pipelines for microscopy images. We present a convolution neural network (CNN) based deep learning architecture for segmentation of objects in microscopy images. The proposed network can be used to segment cells, nuclei and glands in fluorescence microscopy and histology images after slight tuning of input parameters. The network trains at multiple resolutions of the input image, connects the intermediate layers for better localization and context and generates the output using multi-resolution deconvolution filters. The extra convolutional layers which bypass the max-pooling operation allow the network to train for variable input intensities and object size and make it robust to noisy data. We compare our results on publicly available data sets and show that the proposed network outperforms recent deep learning algorithms

長者學習研究計劃2011-2012 : 計劃介紹及教材冊

有見長者的學歷及學習能力日高，長者的需求亦有所不同，對長者需求的研究實是需要的。加上部份長者表示希望參與較高層次的學習活動及貢獻社會，故嶺南大學服務研習處舉辦長者學習研究計劃2011-2012，培訓長者成為研究人員，期望由長者的角度出發，為長者學習 的長遠發展作出研究及提出建議。 計劃目標： • 培養長者對學術研究的興趣； • 提供研究技巧培訓課程； • 分析學苑現有課程的成效； • 探討長者學習的政策及制定長遠發展方向； • 透過長幼參與研究計劃，增加兩代溝通，促進跨代共融。 本手冊收錄了有關計劃詳情以及課程教材。https://commons.ln.edu.hk/osl_book/1002/thumbnail.jp

Effects of physical activity on functional health of older adults: a systematic review

Reviews on the relationships between functional health and physical activity of general older adults have been well documented in literature. However, specific age range of older adults, in particular, older adults of 75 years or above, is currently under-examined. A systematic review was conducted to investigate the effects of physical activity on functional health older adults aged 75 years or above. The reviewed articles cover a variety range of functional health outcomes, including balance, muscle conditioning, joint range of motion, quadriceps strength, reaction time, gait speed, health-related quality of life, back and knee pain, muscle mass, and walking ability. In general, interventions of the reviewed articles had favourable effects on function health of older adults. While physical activity has been identified as an important determinant of functional health, the ways to engage in and accumulate sufficient daily physical activity warrant investigation. It is also important to explore interventions which enhance daily, self-driven physical activity of elderly, as normally supervised physical activity bears higher costs

A handbook for using elder academy as a platform of other learning experiences

This handbook will discuss how school syllabus, Other Learning Experiences (OLE) and Elder Academy (EA) can be integrated. It will provide some structures for schools as a reference and help develop a comprehensive learning plan. Besides, the handbook will mention different roles and responsibilities of stakeholders, as well as the suggestions and guidelines for assessment. The programs and activities in the “Elder Academy at Lingnan” will be taken as examples to demonstrate the guidelines. This can provide a better understanding of the operation mode of the integration between school curricula, OLE and EA. Hence, interested stakeholders can perform their own plans more systematically and effectively.https://commons.ln.edu.hk/osl_book/1000/thumbnail.jp