Phase retrieval with physics informed zero-shot learning

Phase can be reliably estimated from a single diffracted intensity image, if a faithful prior information about the object is available. Examples include amplitude bounds, object support, sparsity in the spatial or a transform domain, deep image prior and the prior learnt from the labelled datasets by a deep neural network. Deep learning facilitates state of art reconstruction quality but requires a large labelled dataset (ground truth-measurement pair acquired in the same experimental conditions) for training. To alleviate this data requirement problem, this letter proposes a zero-shot learning method. The letter demonstrates that the object-prior learnt by a deep neural network while being trained for a denoising task can also be utilized for the phase retrieval, if the diffraction physics is effectively enforced on the network output. The letter additionally demonstrates that the incorporation of total variation in the proposed zero-shot framework facilitates the reconstruction of similar quality in lesser time (e.g. ~8.5 fold, for a test reported in this letter)

Dynamics of Drop Release from the Edge of a Spinning Disc

The direct formation of drops at the edge of a spinning disc is of fundamental interest. We use high-speed imaging to report here on the process of release of drops from a perfectly wetted disc at low inflow rates. A drop-detachment event begins by forming an incipient bulge on the disc edge, which grows into a series of shapestriangle, inverted U, pear, and finally a nearly spherical bulge connected to the disc with an elongated neck. Neck pinching at the base of the bulge releases a primary drop followed by several secondary drops. The drop shape versus time plots show high variability under fixed conditions, which disappears on a single curve for time scaled with individual drop cycle time. The measurements at a different disc speed show the same scaled time evolution, pointing to a universal drop release process. The rapid stretching of the liquid thread as the bulge moves away before pinch-off follows a parabolic relationship with time but with only half the relative acceleration of a free object released from the disc edge. The mean values of cycle time and necking time follow a power-law decrease with disc speed. All of the drops generated in a single event move with the speed of the disc. There is no slip, which is not the case with the ligament mode of breakup. The intervals of quiescence between the successive release of drops from the entire disc follow the Poisson process

SARS-CoV-2 spike protein structure, conformation, and targets of RBD-dependent mAbs.

(A) SARS-CoV-2 spike protein regions with amino acid position numbering are shown, which includes S1 domain regions: the SP, NTD, RBD, and RBM and S2 domain regions: FP, HR1 and HR2, TM, and CP. The glycosylation sites are numbered and marked with Y-like structures in blue. (B) Different conformations of spike protein (PDB: 7DF3, 6XKL, 7EB5, and 7KML, left to right). (C) Representation of 4 classes of SARS-CoV-2 RBD dependent mAbs. Antibody variable heavy chain region (sky blue) and light chain variable region (magenta) are marked. Antibody constant regions were removed from the bound Fab for clarity. The RBD is shown in (pale green) color and antibody contacts on RBD are marked in red (PDB ID: left to right, 7CM4 (CT-P59), 7CHF (BD-368-2), 7K90 (C144), and 6R6X (S304 (left) and S309 (right)). RBD class IV core II region targeting mAbs are shown in blue. CP, cytoplasmic tail; FP, fusion peptide; HR1, heptad repeat 1; HR2, heptad repeat 2; mAb, monoclonal antibody; NTD, N-terminal domain; PDB, Protein Data Bank; RBD, receptor-binding domain; RBM, receptor-binding motif; SARS-CoV-2, Severe Acute Respiratory Syndrome Coronavirus 2; SP, signal peptide; TM, transmembrane domain.</p

Lensless in-line holographic microscopy with light source of low spatio-temporal coherence

Lensless microscopy with coherent or partially coherent light sources is a well known imaging technique, commonly referred as digital in-line holographic microscopy. In the established methods, both the spatial and temporal coherence of light play a crucial role in determining the resolution of reconstructed object. We report lensless microscopy with a spatially extended white LED, a light source of low spatial and very low temporal coherence. The wave-field propagation between two parallel planes can be obtained using a convolution operation, where the convolution kernel depends on the object-sensor distance and the characteristics of the light source. For a light source of unknown characteristics, this kernel is an unknown function. In the proposed reconstruction method, we decompose an unknown convolution kernel of very large size (128 X 128) into a small unknown light-source-specific kernel (size 9 X 9) and a known light-source-independent kernel (size 128 X 128). This drastically reduces the number of parameters to be estimated at the system identification step, which has been performed here by one time imaging of the known microscopic objects. Final unknown object estimation has been performed using the upper-bound constrained deconvolution. A lateral resolution of ~1-2 micrometer has been demonstrated

Additional file 1 of Linker histone variant H1t is closely associated with repressed repeat-element chromatin domains in pachytene spermatocytes

Additional file 1: Figure S1. A. Coomassie-stained gel showing the successful purification of His tagged C-terminal fragment of H1t. The purity of proteins was determined after elution using 100 mM, 200 mM, 300 mM, and 400 mM imidazole, wherein the protein fractions were obtained after elution using 300/400 mM concentration of imidazole. (B-C) Validation of specificity of the H1t antibody towards the recombinant H1t C-terminal protein fragment by ELISA using B. Immune sera and C. Purified antibody. The sera, as well as purified antibodies, showed reactivity against the H1t C-terminal protein fragment. The color code schemes have been indicated on the right of the figures. D. Immunoblotting using anti-H1t and anti-H1.2 antibodies probing against acid extracted histones from liver of 20-day old mouse. H1t is absent in the liver acid extracts, whereas the somatic H1.2 is found in the liver histone extracts. The ponceau stained blots and coomassie blue-stained SDS gel are given for reference

Additional file 9 of Linker histone variant H1t is closely associated with repressed repeat-element chromatin domains in pachytene spermatocytes

Additional file 9. H1t and associated heterochromatin-related proteins

Neutralization potential of therapeutic mAbs against SARS-CoV-2 VOCs and VOIs.

(A) Neutralization potential of SARS-CoV-2 mAbs at various stages of development/clinic against VOCs and VOIs. Here, fold change represents the reduction in IC50 values of SARS-CoV-2 variant neutralization in comparison to wild-types virus. The abbreviations for mAbs in the clinic (EUA) are the following: Bam, Bamlanivimab (LY-CoV555); Ete, Etesevimab (LY-CoV016 or JS016 or CB6); Bam/Ete, Bamlanivimab+Etesevimab; Cas, Casirivimab (REGN10933); Imd, Imdevimab (REGN10987); Cas/Imd, Casirivimab+imdevimab (REGN-COV2); Cil, Cilgavimab (COV2-2130 or AZD1061); Tix, Tixagevimab (COV2-2196 or AZD8895); Tix/Cil, Tixagevimab+Cilgavimab; Sot, Sotrovimab (Vir-7831 or S309); Reg, Regdanvimab (CT-P59). (B) List of mutations present in the current SARS-CoV-2 VOCs and VOIs. EUA, emergency use authorization; mAb, monoclonal antibody; RBD, receptor-binding domain; S2, S2 subunit; SARS-CoV-2, Severe Acute Respiratory Syndrome Coronavirus 2; SD1, subdomain 1; SD2, subdomain 2; SP, signal peptide; VOC, variant of concern; VOI, variant of interest.</p

Geometric Solution of Image Degradation by Diffraction in Lensless Sensing and Microscopy

This paper proposes a non-computational method of counteracting the effect of image degradation introduced by the diffraction phenomenon in lensless microscopy. All the optical images (whether focused by lenses or not) are diffraction patterns, which preserve the visual information upto a certain extent determined by the size of the point spread functions, like airy disks in some cases. A highly diverging beam can be exploited to reduce the spatial extent of these point spread functions relatively in the transformed projective space, which can help us in the spatial unmixing of the visual information. The principle has been experimentally validated by the lensless imaging of red blood cells of diameter ~6-9 micrometers and a photolithography mask with features in micrometer scale. The important advantages of the proposed approach of non-computational shadow microscopy are the improved depth of field and a drastic increase in the sensor to sample working distance. The imaging method can also be used as a projection technique in the multi-angle optical computed tomography (CT)

Additional file 2 of Linker histone variant H1t is closely associated with repressed repeat-element chromatin domains in pachytene spermatocytes

Additional file 2: Figure S2. A. Western blotting analysis of rat testicular perchloric acid extracts using H1t and H1.2 antibodies confirming the specificity of the H1t and H1.2 antibodies. The blots to the right are the immunoblotting results obtained after preincubation of the H1t and H1.2 antibodies with the recombinant H1t C-terminal antigen. B. Immunoblotting performed with H1t and H1.2 antibodies probed against rat testicular acid extracts. The blots to the left represent the immunoblotting pattern obtained against the rat testicular acid extracts. The blots to the right indicate the results obtained after performing the protein competition assay with the H1t C-terminal antigen. The reactivity of the H1t antibodies but not H1.2, was abolished upon preincubation with the recombinant H1t C-terminal protein fragment. Ponceau stained blots and Coomassie-stained gel are given for reference

Work-readiness integrated competence model: Conceptualisation and scale development

Purpose The purpose of this paper is to conceptualise graduate work-readiness and to develop a scale to measure it. Design/methodology The methodology entailed the compilation of a literature review and the conduct of qualitative interviews and a focus group to generate items. This study used the ‘resource-based view (RBV)’ approach to conceptualise a multidimensional – ‘Work-readiness integrated competence model (WRICM)’– consisting of four main factors (namely, intellectual, personality, meta skill and job-specific resources), with a further ten sub-dimensions. Further, a series of tests were performed to assess its reliability and validity. Findings A final 53 item WRICM scale covering four dimensions and ten sub-dimensions of graduate work-readiness was developed based on the perceptions of 362 HR professionals and managers from seven Asia-Pacific countries. The ten sub-dimensions covering 53 work readiness skills reflect the perceptions of stakeholders regarding the work-readiness of graduates. The scale was found to be psychometrically sound for measuring graduate work-readiness. Research limitations Though the WRICM model is based on the inputs of different stakeholders of graduate work-readiness (employers, educators, policy-makers and graduates), the development of the WRICM scale is based on the perspectives of industry/employers only. Practical implications The WRICM model has implications for education, industry, professional associations, policy-makers and for graduates. These stakeholders can adapt this scale in assessing the work-readiness of graduates in different streams of education. Originality/value The authors believe that the WRICM model is the first multi-dimensional construct that is based on a sound theory and from the inputs from graduate work- readiness stakeholders from seven Asia Pacific countries