There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

We report a method to form multifunctional polymer coatings through simple dip-coating of objects in an aqueous solution of dopamine. Inspired by the composition of adhesive proteins in mussels, we used dopamine self-polymerization to form thin, surface-adherent polydopamine films onto a wide range of inorganic and organic materials, including noble metals, oxides, polymers, semiconductors, and ceramics. Secondary reactions can be used to create a variety of ad-layers, including self-assembled monolayers through deposition of long-chain molecular building blocks, metal films by electroless metallization, and bioinert and bioactive surfaces via grafting of macromolecules.

/pdf/mussel-inspired-surface-chemistry-for-multifunctional-1noq7vcby7.pdf

Mussel-Inspired Surface Chemistry for Multifunctional Coatings

Biological effects of essential oils - A review

BIOE 402. Medical Technology Assessment. 2 or 3 hours. Bioentrepreneur course. Assessment of medical technology in the context of commercialization. Objectives, competition, market share, funding, pricing, manufacturing, growth, and intellectual property; many issues unique to biomedical products. Course Information: 2 undergraduate hours. 3 graduate hours. Prerequisite(s): Junior standing or above and consent of the instructor.

“Bioinformatics” 특집을 내면서

X-ray ptychography imaging at synchrotron facilities like the Advanced Photon Source (APS) involves controlling instrument hardwares to collect a set of diffraction patterns from overlapping coherent illumination spots on extended samples, managing data storage, reconstructing ptychographic images from acquired diffraction patterns, and providing the visualization of results and feedback. In addition to the complicated workflow, ptychography instrument could produce up to several TB’s of data per second that is needed to be processed in real time. This brings up the need to develop a high performance, robust and user friendly processing software package for ptychographic data analysis. In this paper we present a software framework which provides functionality of visualization, work flow control, and data reconstruction. To accelerate the computation and large datasets process, the data reconstruction part is implemented with three algorithms, ePIE,1 DM2 and LSQML3 using CUDA-C on GPU.

Ptychopy: GPU framework for ptychographic data analysis

The X-ray Fluorescence (XRF) is one of the most important tools for elemental quantification and mapping in biological and medical samples[1]. Our recent efforts has been focused on expansion of regular two-dimensional X-ray Fluorescence imaging in order to obtain three-dimensional distribution of various elements within relatively large sample without sectioning, which may result in sample damages and artifacts. We have improved XRF set up and tested different data acquisition schemes for optimal tomographic reconstructions using TomoPy [2].

/pdf/developments-of-x-ray-fluorescence-tomography-at-2-id-e-at-4kmed1eerp.pdf

Developments of X-ray Fluorescence Tomography at 2-ID-E at APS for Studies of Composite Samples

Zone plates are diffractive focusing optics capable of nanometer focusing but limited focusing efficiency at hard x-ray energy. A smaller focus spot is possible by reducing the outer zone width (OZW) while increasing the zone height will generally increase focusing efficiency. The combination of thick zones with small outer zone width, or high aspect ratio, for better performing zone plates is not feasible with state-of-the-art fabrication methods and requires other methods to achieve the aspect ratio desired. Near-field stacking involves two zone plates with the same dimensions and aligning them within the depth of focus in the beam direction and one third of the OZW in the transverse direction. Due to the depth of focus limitation, stacking more than 2 zone plates is extremely difficult, so a new method was proposed and developed to stack zone plates in the intermediate field. Multiple stacking apparatuses were assembled and tested. We will report on results from stacking 80-nm OZW zone plates from a near-field stacking experiment at 10 keV X-ray energy and intermediate field stacking 6 zone plates at 27 keV X-ray energy. We will also present findings on how to combine the stacking techniques.

Stacking multiple zone plates for efficient hard x-ray focusing at the Advanced Photon Source

Differential phase contrast can be realised in the scanning transmission x-ray microscope by use of a detector with an appropriate configuration of detector elements. Use of such a configured detector significantly improves the ability to image specimens with low absorption contrast. A natural application is found in scanning fluorescence x-ray microprobe studies of biological specimens. We discuss the technique and several applications.

/pdf/quantitative-scanning-differential-phase-contrast-microscopy-4sto8i5qjv.pdf

Quantitative scanning differential phase contrast microscopy

Copper based waterborne wood preservatives are frequently used to extend the service life of wood products when subjected to frequent moisture exposure. While these copper based treatments protect the wood from fungal decay and insect attack, they increase the corrosion of metals embedded or in contact with the treated wood. Previous research has shown the most plausible corrosion mechanism involves the migration of copper ions from the wood treatment through the wood to the metal surface, where they are then reduced. Despite this, under almost all conditions, copper has not been detected in the corrosion products as the proposed mechanism would imply. Recently, synchrotron based X-ray fluorescence microscopy (XFM) was used to examine the wood that had been in direct contact with metal fasteners in a corrosion test. These measurements showed a copper depleted region in the wood directly adjacent to the metal fastener. Based on the size of the region and the copper concentration, the amount of copper in the corrosion products was calculated to be on the order of 500 parts per million. This low concentration explains why previous attempts to find copper in the corrosion products using scanning electron microscopy, energy dispersive X-ray spectroscopy, and powder X-ray diffraction were unsuccessful. Here, we present XFM maps of corrosion products removed from corroded fasteners that had been in contact with preservative treated wood. The XFM maps of the corrosion products clearly show the presence of copper. These measurements definitively confirm the mechanism of corrosion in treated wood and give further insights into where and how the cathodic reaction takes place.

https://www.fpl.fs.fed.us/documnts/pdf2017/fpl_2017_zelinka002.pdf

Stefan Vogt

Papers

Ptychopy: GPU framework for ptychographic data analysis

Developments of X-ray Fluorescence Tomography at 2-ID-E at APS for Studies of Composite Samples

Stacking multiple zone plates for efficient hard x-ray focusing at the Advanced Photon Source

Quantitative scanning differential phase contrast microscopy

Synchrotron Based X-ray Fluorescence Microscopy Confirms Copper in the Corrosion Products of Metals in Contact with Treated Wood