Optimal Coded Diffraction Patterns for Practical Phase Retrieval

Phase retrieval, a long-established challenge for recovering a complex-valued signal from its Fourier intensity measurements, has attracted significant interest because of its far-flung applications in optical imaging. To enhance accuracy, researchers introduce extra constraints to the measuring procedure by including a random aperture mask in the optical path that randomly modulates the light projected on the target object and gives the coded diffraction patterns (CDP). It is known that random masks are non-bandlimited and can lead to considerable high-frequency components in the Fourier intensity measurements. These high-frequency components can be beyond the Nyquist frequency of the optical system and are thus ignored by the phase retrieval optimization algorithms, resulting in degraded reconstruction performances. Recently, our team developed a binary green noise masking scheme that can significantly reduce the high-frequency components in the measurement. However, the scheme cannot be extended to generate multiple-level aperture masks. This paper proposes a two-stage optimization algorithm to generate multi-level random masks named $\textit{OptMask}$ that can also significantly reduce high-frequency components in the measurements but achieve higher accuracy than the binary masking scheme. Extensive experiments on a practical optical platform were conducted. The results demonstrate the superiority and practicality of the proposed $\textit{OptMask}$ over the existing masking schemes for CDP phase retrieval

Inhibition of autophagy enhances SMI-4a-induced growth inhibition and apoptosis of melanoma cells

Purpose: To investigate the exact role of the proviral integration site for Moloney  murine leukemia virus-1 (PIM-1) on autophagy as well as the underlying molecular  mechanisms in melanoma.Methods: mRNA expression levels in A375 and G361 human melanoma cell lines were measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Enzyme-linked immunosorbent (ELISA) and western blotting assays were applied to determine protein expression levels, while cell viability was evaluated using Cell Counting Kit 8 and colony formation assay. Flow cytometric analysis and caspase 3/7 activity assay were used to assess apoptosis.Results: The results show that pharmacological inhibition of PIM-1 with its potent inhibitor (SMI-4a) suppressed cell viability and induced apoptosis in melanoma cell lines A375 and G361. SMI-4a also induced autophagy through inhibition of the phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) axis in melanoma cells. Furthermore, chloroquine, an inhibitor of autophagy, potentiated the SMI-4a-induced inhibition of tumour growth and promotion of  apoptosis in melanoma cells in vitro and in vivo.Conclusions: These results suggest that SMI-4a induces protective autophagy via PI3K/AKT/mTOR signaling pathway in melanoma cells. Thus, a combination of SMI-4a and an inhibitor of autophagy might be a novel approach to melanoma therapy.Keywords: Apoptosis, Autophagy, Cell viability, Melanoma, PIM-1, SMI-4

Radiosurgery for Vestibular Schwannomas

BackgroundRadiosurgery has been established as an important alternative to microsurgery. We report our experience with radiosurgery for tumor control and the complications of unilateral vestibular schwannomas.MethodsWe reviewed our early experience regarding clinical presentation, management and outcomes in 45 patients with acoustic schwannomas who underwent gamma knife stereotactic radiosurgery. The median follow-up period was 25 months (range, 6-48 months). Thirteen patients had undergone 1 or more previous resections before radiosurgery; 32 underwent radiosurgery as the first procedure. Median tumor volume was 4.5 mL (range, 0.5-30.0), and median radiotherapy dose was 11.5 Gy (range, 10.5-14.0 Gy).ResultsTumor control was achieved in 43 patients (95.6%). Loss of central contrast enhancement was a characteristic change and was noted in 29 patients (64.4%). Reduction in tumor size was shown in 15 patients (33.3%). Thirteen patients (28.9%) had good or serviceable hearing preoperatively, and in all of these, the preoperative status was retained immediately after radiosurgery. At follow-up, however, 10 patients (76.9%) had preserved hearing and 3 (23.1%) had reduced hearing on the treated side. Hearing in 1 patient that was not serviceable preoperatively later improved to a serviceable level. No patients had delayed facial palsy or lower cranial nerve dysfunction, but one had delayed trigeminal sensory loss.ConclusionRadiosurgery achieved a high tumor control rate and a relatively low post-radiosurgical complication rate for acoustic neuromas

Interpretable Fully Convolutional Classification of Intrapapillary Capillary Loops for Real-Time Detection of Early Squamous Neoplasia

In this work, we have concentrated our efforts on the interpretability of classification results coming from a fully convolutional neural network. Motivated by the classification of oesophageal tissue for real-time detection of early squamous neoplasia, the most frequent kind of oesophageal cancer in Asia, we present a new dataset and a novel deep learning method that by means of deep supervision and a newly introduced concept, the embedded Class Activation Map (eCAM), focuses on the interpretability of results as a design constraint of a convolutional network. We present a new approach to visualise attention that aims to give some insights on those areas of the oesophageal tissue that lead a network to conclude that the images belong to a particular class and compare them with those visual features employed by clinicians to produce a clinical diagnosis. In comparison to a baseline method which does not feature deep supervision but provides attention by grafting Class Activation Maps, we improve the F1-score from 87.3% to 92.7% and provide more detailed attention maps