Automated differentiation of skin melanocytes from keratinocytes in high-resolution histopathology images using a weakly-supervised deep-learning framework

Early detection and accurate diagnosis of melanoma skin cancer which accounts for 75% of all skin cancer mortalities would significantly improve survival rates. Melanoma is characterized by an abnormal proliferation of malignant melanocytes in the epidermis of the skin, which is composed predominantly of keratinocytes. Localization and differentiation of melanocytes from keratinocytes in the skin in whole slide images (WSIs) is an important initial task towards the diagnosis of the tumor. Because of the small size of melanocytes and the dominance of keratinocytes in the epidermis, identification of melanocytes can be challenging and prone to errors. We propose a new fully-automated framework based on deep-machine learning to identify melanocytes and keratinocytes with detection accuracy of 90.5% and 87.4%, respectively. This framework begins with segmenting the epidermis layer inside 640 × 320 × 3 super tiles of WSIs using a DeepLabV3+ model followed by a weakly-supervised deep learning approach deploying a fine-tuned pre-trained visual geometry group (VGG)-16 model, gradient-weighted class activation mapping (Grad-CAM), Otsu's and contour estimation methods in order to identify melanocytes and keratinocytes inside each 64 × 64 × 3 tile (i.e., a subdivision of the super tile). The proposed framework outperforms the state-of-the-art methods as well as provides a significant improvement of 28% and 17% over the fully supervised faster region-based convolutional neural network (R-CNN) in detecting melanocytes and keratinocytes respectively without the need for expensive expert fine labels for model training and validation. The proposed framework offers a promising accurate tool to aid pathologists in differentiating melanocytes from keratinocytes that would eventually support the diagnosis of melanoma.     

On the complexity of or-parallelism

We formalize the implementation mechanisms required to support or-parallel execution of logic programs in terms of operations on dynamic data structures. Upper and lower bounds are derived, in terms of the number of operationsn performed on the data structure, for the problem of guaranteeing correct semantics during or-parallel execution. The lower bound Ω(lgn) formally proves the impossibility of achieving an ideal implementation (i.e., parallel implementation with constant time overhead per operation). We also derive an upper bound of $\tilde O\left( {\sqrt[3]{n}} \right)$ per operation for or-parallel execution. This upper bound is far better than what has been achieved in the existing or-parallel systems and indicates that faster implementations may be feasible.     

Immunogold FIB‐SEM: Combining Volumetric Ultrastructure Visualization with 3D Biomolecular Analysis to Dissect Cell–Environment Interactions

Volumetric imaging techniques capable of correlating structural and functional information with nanoscale resolution are necessary to broaden the insight into cellular processes within complex biological systems. The recent emergence of focused ion beam scanning electron microscopy (FIB‐SEM) has provided unparalleled insight through the volumetric investigation of ultrastructure; however, it does not provide biomolecular information at equivalent resolution. Here, immunogold FIB‐SEM, which combines antigen labeling with in situ FIB‐SEM imaging, is developed in order to spatially map ultrastructural and biomolecular information simultaneously. This method is applied to investigate two different cell–material systems: the localization of histone epigenetic modifications in neural stem cells cultured on microstructured substrates and the distribution of nuclear pore complexes in myoblasts differentiated on a soft hydrogel surface. Immunogold FIB‐SEM offers the potential for broad applicability to correlate structure and function with nanoscale resolution when addressing questions across cell biology, biomaterials, and regenerative medicine.     

HermesB: a continuous neural recording system for freely behaving primates

Chronically implanted electrode arrays have enabled a broad range of advances in basic electrophysiology and neural prosthetics. Those successes motivate new experiments, particularly, the development of prototype implantable prosthetic processors for continuous use in freely behaving subjects, both monkeys and humans. However, traditional experimental techniques require the subject to be restrained, limiting both the types and duration of experiments. In this paper, we present a dual-channel, battery-powered neural recording system with an integrated three-axis accelerometer for use with chronically implanted electrode arrays in freely behaving primates. The recording system called HermesB, is self-contained, autonomous, programmable, and capable of recording broadband neural (sampled at 30 kS/s) and acceleration data to a removable compact flash card for up to 48 h. We have collected long-duration data sets with HermesB from an adult macaque monkey which provide insight into time scales and free behaviors inaccessible under traditional experiments. Variations in action potential shape and root-mean square (RMS) noise are observed across a range of time scales. The peak-to-peak voltage of action potentials varied by up to 30% over a 24-h period including step changes in waveform amplitude (up to 25%) coincident with high acceleration movements of the head. These initial results suggest that spike-sorting algorithms can no longer assume stable neural signals and will need to transition to adaptive signal processing methodologies to maximize performance. During physically active periods (defined by head-mounted accelerometer), significantly reduced 5-25-Hz local field potential (LFP) power and increased firing rate variability were observed. Using a threshold fit to LFP power, 93% of 403 5-min recording blocks were correctly classified as active or inactive, potentially providing an efficient tool for identifying different behavioral contexts in prosthetic applications. These results demonstrate the utility of the HermesB system and motivate using this type of system to advance neural prosthetics and electrophysiological experiments.     

Modeling of a domestic frost-free refrigerator

In the present study, a comprehensive thermo-fluidic model is developed for a domestic frost-free refrigerator. The governing equations, coupled with pertinent boundary conditions, are solved by employing a conservative control volume formulation, in the environment of a three-dimensional unstructured mesh. Experiments are also conducted to validate the results predicted by the present computational model. It is found that the computational and experimental results qualitatively agree with each other, although certain discrepancies can be observed in terms of the exact numerical values obtained. For the freezer compartment, the computationally predicted temperatures are somewhat higher than the experimental ones, whereas for the refrigerating compartment, the computed temperatures are lower than the corresponding experimental observations. The difference between experimental and computational results may be attributed to the lack of precise data on the airflow rates and the unaccounted heat transfer rates through the door gaskets and the compressor. From the heat transfer and fluid flow analysis, certain modifications in the design are also suggested, so as to improve the performance of the refrigerator.     

Patient exposure tracking: the IAEA smart card project

The existing approach of radiation protection is largely based on the collective dose to the population with provisions for protection at an individual level through justification and optimisation. With the individual patient dose now exceeding the life-long occupational dose to a worker in a typical radiology practice, there is a need to establish approaches based on the protection of an individual patient. Radiation exposure tracking seems a way forward in this respect. Technological advances in recent years have provided opportunities for tracking to becoming a reality. The IAEA project on Smart Card/SmartRadTrack is described in this paper. The tracking is now a reality in a few dozen centres in many countries connected by picture archiving and communication systems, and there is hope that this will extend to cover other countries and continents.     

Medical radiation protection in next decade

Interest in medical radiation protection today is the same as what it would have been almost a century ago. After many decades of relatively safe application of radiation in medicine, the recent spurt in over exposures, over-use of imaging and accidental exposures has created the need for stakeholders to join hands and contribute towards increasing radiation safety levels. Whether it be the need for technological developments to achieve sub-mSv CT scans, tracking of patient exposure history, accounting for repeated exposures of the same patient, specific consideration of requests for radiological examinations that deliver few mSv of dose, or utilization of regulatory approaches, radiological equipment will need to alert users whenever the radiation dose to the patient is above a defined value. The current decade will focus increasingly on carcinogenic effects in patients.     

CuO nano-whiskers: Electrodeposition,Raman analysis,photoluminescence study and photocatalytic activity

An electrochemical route to synthesize CuO thin films with nano-whiskers like structure, from a metallic Cu precursor is reported. Structural characterization showed the formation of cubic phase for both the Cu and CuO films, whereas, the grains were found to change their shapes from cubic to nano-whiskers as an effect of annealing (in air at 600 °C for 30 min). X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis, Photoluminescence (PL) and Raman analyses were carried out with the films. The photocatalytic activity of the prepared CuO films was determined by measuring the degradation of Rose Bengal (RB) dye, to find out its potential application in waste water treatment.     

Molecular interaction and properties of poly(ether ether ketone)/liquid crystalline polymer blends incorporated with functionalized carbon nanotubes

Multi-walled carbon nanotubes (MWCNTs) were functionalized with a carboxyl group (-COOH) to achieve better interfacial adhesions with both phases of the poly(ether ether ketone) (PEEK) and liquid crystalline polymer (LCP) in their blend. These strong interfacial interactions among the functionalized MWCNTs, PEEK and LCP improved the mechanical properties of the polymer blend. Three different weight percentages (0.6%, 1.2% and 1.8%) of acid modified CNTs were used with PEEK-LCP blend, for the preparation of nanocomposites. In PEEK-LCP blend, the ratio of PEEK and LCP was maintained as 10:6 respectively. The tensile strength and modulus of the composites were improved by 51% and 73% respectively with the incorporation of only 1.2% of MWCNT-COOH as compared to the unfilled PEEK/LCP blend. Moreover, careful studies of the molecular interaction, morphological, dynamic mechanical and thermal properties confirmed that a better miscibility between PEEK and LCP had been constituted in the presence of MWCNT-COOH. Therefore, it was found that the functionalized MWCNTs not only played the traditional role as reinforcing filler, but also performed a novel role as a compatibilizer for the PEEK/LCP blends.