Elastic 3-D alignment of rat brain histological images

A three-dimensional wavelet-based algorithm for nonlinear registration of an elastic body model of the brain is developed. Surfaces of external and internal anatomic brain structures are used to guide alignment. The deformation field is represented with a multiresolution wavelet expansion and is modeled by the partial differential equations of linear elasticity. A progressive estimation of the registration parameters and the usage of an adaptive distance map reduce algorithm complexity, thereby providing computational flexibility that allows mapping of large, high resolution datasets. The performance of the algorithm was evaluated on rat brains. The wavelet-based registration method yielded a twofold improvement over affine registration.     

Synthesis and characterization of the crystalline powders on the basis of Lu2O3:Eu3+spherical submicron-sized particles

This study is devoted to the preparation of the crystalline powders on the basis of non-agglomerated monodisperse Lu₂O₃:Eu³⁺ spherical particles with the diameters in the range of 50–250 nm by the soft chemistry co-precipitation route. The influence of the synthesis parameters on control morphology, particles size and agglomeration in the final Lu₂O₃:Eu³⁺ powder was considered. Lu₂O₃:Eu³⁺ crystalline powders were characterized by means of electron microscopy methods (TEM, SEM), FT-IR spectroscopy, thermal analysis (TG-DTA) and X-ray diffractometry. The mechanisms of the precursor decomposition and crystallization at the temperatures ranging from 60 to 900 °C were discussed. It was shown that the powders obtained were characterized by the effective luminescence under X-ray excitation in λ = 575–725 nm spectral region corresponding to ⁵D₀ → ⁷F_J transitions (J = 0–4) of Eu³⁺ ions with a maximum at 612 nm and the luminescence intensity strongly depends on annealing temperature. The relative densities of the green-bodies on the basis of Lu₂O₃:Eu³⁺ powders were estimated and the sintering of compacts at the temperatures up to 1500 °C was studied.     

ROC analysis of ultrasound tissue characterization classifiers for breast cancer diagnosis

Breast cancer diagnosis through ultrasound tissue characterization was studied using receiver operating characteristic (ROC) analysis of combinations of acoustic features, patient age, and radiological findings. A feature fusion method was devised that operates even if only partial diagnostic data are available. The ROC methodology uses ordinal dominance theory and bootstrap resampling to evaluate A(z) and confidence intervals in simple as well as paired data analyses. The combined diagnostic feature had an A(z) of 0.96 with a confidence interval of at a significance level of 0.05. The combined features show statistically significant improvement over prebiopsy radiological findings. These results indicate that ultrasound tissue characterization, in combination with patient record and clinical findings, may greatly reduce the need to perform biopsies of benign breast lesions.     

Synthesis of reactive copolymers with peroxide functionality for cross-linking water-soluble polymers

A series of reactive copolymers with peroxide functionality (RCPFs) were synthesized via radical copolymerization of monomer mixtures in an organic solvent comprised of a peroxide monomer 5-(tert-butyl peroxy)-5-methylhex-1-en-3-yne, acrylamide, maleic anhydride, and butyl methacrylate. Peroxide functionality allows the RCPFs to initiate a variety of radical processes, including cross-linking of organic polymers. Hydrophilic monomer subunits (acrylamide and maleic anhydride) within the RCPF macromolecules promote cross-linking of water-soluble polymers. We aimed to investigate RCPF comonomer ratio and its effects on copolymerization kinetics and composition, as well as physico-chemical and colloidal properties. We also evaluated and characterized the kinetic parameters of the thermal decomposition of peroxide moieties in the synthesized RCPF. Findings revealed that RCPF possessed surface-active properties and reduced surface tension at its aqueous solution–air interface. The data indicated that the decomposition process complied with the first-order kinetics, and complex thermal analysis confirmed the presence of peroxide moieties. RCPFs' ability to cross-link water-soluble polymers was demonstrated on poly(acrylamide) and poly(vinyl alcohol).     

Spin-Flip Raman Scattering on Electrons and Holes in Two-Dimensional (PEA)2PbI4 Perovskites

The class of Ruddlesden–Popper type (PEA)₂PbI₄ perovskites comprises 2D structures whose optical properties are determined by excitons with a large binding energy of about 260 meV. It complements the family of other 2D semiconductor materials by having the band structure typical for lead halide perovskites, that can be considered as inverted compared to conventional III–V and II–VI semiconductors. Accordingly, novel spin phenomena can be expected for them. Spin-flip Raman scattering is used here to measure the Zeeman splitting of electrons and holes in a magnetic field up to 10 T. From the recorded data, the electron and hole Landé factors (g-factors) are evaluated, their signs are determined, and their anisotropies are measured. The electron g-factor value changes from +2.11 out-of-plane to +2.50 in-plane, while the hole g-factor ranges between -0.13 and -0.51. The spin flips of the resident carriers are arranged via their interaction with photogenerated excitons. Also the double spin-flip process, where a resident electron and a resident hole interact with the same exciton, is observed showing a cumulative Raman shift. Dynamic nuclear spin polarization induced by spin-polarized holes is detected in corresponding changes of the hole Zeeman splitting. An Overhauser field of the polarized nuclei acting on the holes as large as 0.6 T can be achieved.     

Nano-Theranostic Modality for Visualization of the Placenta and Photo-Hyperthermia for Potential Management of Ectopic Pregnancy

Ectopic pregnancy (EP) is the leading cause of maternity-related death in the first trimester of pregnancy. Approximately 98% of ectopic implantations occur in the fallopian tube, and expedient management is crucial for preventing hemorrhage and maternal death in the event of tubal rupture. Current ultrasound strategies misdiagnose EP in up to 40% of cases, and the failure rate of methotrexate treatment for confirmed EP exceeds 10%. Here the first theranostic strategy for potential management of EP is reported using a near-infrared naphthalocyanine dye encapsulated within polymeric nanoparticles. These nanoparticles preferentially accumulate in the developing murine placenta within 24 h following systemic administration, and enable visualization of implantation sites at various gestational stages via fluorescence and photoacoustic imaging. These nanoparticles do not traverse the placental barrier to the fetus or impact fetal development. However, excitation of nanoparticles localized in specific placentas with focused NIR light generates heat (>43 °C) sufficient for disruption of placental function, resulting in the demise of targeted fetuses with no effect on adjacent fetuses. This novel approach would enable diagnostic confirmation of EP when current imaging strategies are unsuccessful, and elimination of EP could subsequently be achieved using the same nano-agent to generate localized hyperthermia resulting in targeted placental impairment.