Compact electrically detected magnetic resonance setup

Electrically detected magnetic resonance (EDMR) is a commonly used technique for the study of spin-dependent transport processes in semiconductor materials and electro-optical devices. Here, we present the design and implementation of a compact setup to measure EDMR, which is based on a commercially available benchtop electron paramagnetic resonance (EPR) spectrometer. The electrical detection part uses mostly off-the-shelf electrical components and is thus highly customizable. We present a characterization and calibration procedure for the instrument that allowed us to quantitatively reproduce results obtained on a silicon-based reference sample with a “large-scale” state-of- the-art instrument. This shows that EDMR can be used in novel contexts relevant for semiconductor device fabrication like clean room environments and even glove boxes. As an application example, we present data on a class of environment-sensitive objects new to EDMR, semiconducting organic microcrystals, and discuss similarities and differences to data obtained for thin-film devices of the same molecule

Synergistic and Additive Effects of Epigallocatechin Gallate and Digitonin on Plasmodium Sporozoite Survival and Motility

BACKGROUND: Most medicinal plants contain a mixture of bioactive compounds, including chemicals that interact with intracellular targets and others that can act as adjuvants to facilitate absorption of polar agents across cellular membranes. However, little is known about synergistic effects between such potential drug candidates and adjuvants. To probe for such effects, we tested the green tea compound epigallocatechin gallate (EGCG) and the membrane permeabilising digitonin on Plasmodium sporozoite motility and viability. METHODOLOGY/PRINCIPAL FINDINGS: Green fluorescent P. berghei sporozoites were imaged using a recently developed visual screening methodology. Motility and viability parameters were automatically analyzed and IC50 values were calculated, and the synergism of drug and adjuvant was assessed by the fractional inhibitory concentration index. Validating our visual screening procedure, we showed that sporozoite motility and liver cell infection is inhibited by EGCG at nontoxic concentrations. Digitonin synergistically increases the cytotoxicity of EGCG on sporozoite survival, but shows an additive effect on sporozoite motility. CONCLUSIONS/SIGNIFICANCE: We proved the feasibility of performing highly reliable visual screens for compounds against Plasmodium sporozoites. We thereby could show an advantage of administering mixtures of plant metabolites on inhibition of cell motility and survival. Although the effective concentration of both drugs is too high for use in malaria prophylaxis, the demonstration of a synergistic effect between two plant compounds could lead to new avenues in drug discovery

P-590: Obesity regulates renal endothelin and endothelin ETA receptor expression in vivo. Differential effects of chronic ETA receptor blockade

ETA receptors have been implicated in obesity-associated hypertension (Hypertension 1999; 33: 1169). We characterized the renal endothelin system in diet-induced obesity and determined the effects of chronic treatment with the ETA antagonist darusentan. C57BL/6J mice were fed a standard diet (control) or a high-fat diet (Harlan TD88137) with or without darusentan (50 mg/kg/d, 30 wk). Total RNA was extracted from whole kidneys and mRNA expression of preproendothelin-1 (ppET-1), ETA receptors, and β-actin were determined by RT-PCR using mouse-specific primers. PCR-products were normalized vs. β-actin or 18S rRNA. Renal ET-1 protein was measured by RIA/HPLC. High fat diet increased body weight by 257% compared to 54% (control diet). Darusentan had no effect on body weight in obese mice (263%) and treatments had no effect on systolic blood pressure. Obesity was associated with upregulation of renal ETA receptors (144±5% vs 100±7%, p<0.05 vs. control) and to a lesser extent, preproendothelin-1 (113±5% vs.100±2%, p<0.05 vs. control). In obese mice chronic darusentan treatment in part prevented the ETA receptor upregulation (126% vs. 144±5%, p<0.05) but had no significant effect on ppET-1 mRNA expression (101±9 vs. 100±2%, n.s.). Renal ET-1 protein increased in obese animals (from 190±18 to 267±19 pg/g tissue, p<0.05 vs. control). This increase was not affected by concomitant darusentan treatment (n.s.). These data for the first time demonstrate that obesity in normotensive rats is associated with upregulation of renal ETA receptor expression suggesting that body weight per se affects ET receptor expression in the kidney. Our data further indicate that in this model ETA receptors control expression of the ETA receptor but not the ppET-1 gene, suggesting autocrine regulation in vivo. These mechanisms might contribute to the pathogenesis of obesity-associated diseases affecting the kidney and/or blood pressur

Setup of an In Vitro Test System for Basic Studies on Biofilm Behavior of Mixed-Species Cultures with Dental and Periodontal Pathogens

BACKGROUND: Caries and periodontitis are important human diseases associated with formation of multi-species biofilms. The involved bacteria are intensively studied to understand the molecular basis of the interactions in such biofilms. This study established a basic in vitro single and mixed-species culture model for oral bacteria combining three complimentary methods. The setup allows a rapid screening for effects in the mutual species interaction. Furthermore, it is easy to handle, inexpensive, and reproducible. METHODS: Streptococcus mitis, S. salivarius and S. sanguinis, typical inhabitants of the healthy oral cavity, S. mutans as main carriogenic species, and Porphyromonas gingivalis, Fusobacterium nucleatum, Parvimonas micra, S. intermedius and Aggregatibacter actinomycetemcomitans as periodontitis-associated bacteria, were investigated for their biofilm forming ability. Different liquid growth media were evaluated. Safranin-staining allowed monitoring of biofilm formation under the chosen conditions. Viable counts and microscopy permitted investigation of biofilm behavior in mixed-species and transwell setups. FINDINGS: S. mitis, F. nucleatum, P. gingivalis and P. micra failed to form biofilm structures. S. mutans, S. sanguinis, S. intermedius and S. salivarius established abundant biofilm masses in CDM/sucrose. A. actinomycetemcomitans formed patchy monolayers. For in depth analysis S. mitis, S. mutans and A. actinomycetemcomitans were chosen, because i) they are representatives of the physiological-, cariogenic and periodontitis-associated bacterial flora, respectively and ii) their difference in their biofilm forming ability. Microscopic analysis confirmed the results of safranin staining. Investigation of two species combinations of S. mitis with either S. mutans or A. actinomycetemcomitans revealed bacterial interactions influencing biofilm mass, biofilm structure and cell viability. CONCLUSIONS: This setup shows safranin staining, microscopic analysis and viable counts together are crucial for basic examination and evaluation of biofilms. Our experiment generated meaningful results, exemplified by the noted S. mitis influence, and allows a fast decision about the most important bacterial interactions which should be investigated in depth

Dynamic contrast in scanning microscopic OCT

While optical coherence tomography (OCT) provides a resolution down to 1 micrometer it has difficulties to visualize cellular structures due to a lack of scattering contrast. By evaluating signal fluctuations, a significant contrast enhancement was demonstrated using time-domain full-field OCT (FF-OCT), which makes cellular and subcellular structures visible. The putative cause of the dynamic OCT signal is ATP-dependent motion of cellular structures in a sub-micrometer range, which provides histology-like contrast. Here we demonstrate dynamic contrast with a scanning frequency-domain OCT (FD-OCT). Given the inherent sectional imaging geometry, scanning FD-OCT provides depth-resolved images across tissue layers, a perspective known from histopathology, much faster and more efficiently than FF-OCT. Both, shorter acquisition times and tomographic depth-sectioning reduce the sensitivity of dynamic contrast for bulk tissue motion artifacts and simplify their correction in post-processing. The implementation of dynamic contrast makes microscopic FD-OCT a promising tool for histological analysis of unstained tissues.Comment: 7 pages, 3 figures, 1 Video available on reques

ARIA digital anamorphosis: Digital transformation of health and care in airway diseases from research to practice

Digital anamorphosis is used to define a distorted image of health and care that may be viewed correctly using digital tools and strategies. MASK digital anamorphosis represents the process used by MASK to develop the digital transformation of health and care in rhinitis. It strengthens the ARIA change management strategy in the prevention and management of airway disease. The MASK strategy is based on validated digital tools. Using the MASK digital tool and the CARAT online enhanced clinical framework, solutions for practical steps of digital enhancement of care are proposed

Задача розрахунку відхилення поверхні тканини для безконтактної фотоакустичної томографії

Background. Photoacoustic tomography (PAT) is a relatively new imaging modality,which allows e.g. visualizing the vascular network in biological tissue noninvasively. This tomographic method has an advantage in comparison to pure optical/acoustical methods due to high optical contrast and low acoustic scattering in deep tissue. The common PAT methodology, based on measurements of the acoustic pressure by piezoelectric sensors placed on the tissue surface, limits its practical versatility. A novel, completely non-contact and full-field PAT system is described. In noncontact PAT the measurement of surface displacement induced by the acoustic pressure at the tissue/air border is researched.Objective. To solve a simulation problem of the displacement calculation based on the medium pressure, which consists in deriving a formula for recalculating the pressure in the surface displacement based on the momentum conservation law, developing a simulation technique, and comparing the error of the proposed technique with the earlier used one.Methods. Comparing the experimental data with simulated pressure data in the k-Wave toolbox. The criterion of comparison is the relative quadratic error.Results. The simulation results of the displacement based on a new approach are more consistent with the experimental data than previous. The quadratic error numerical value of the new approach is 18 % and the previous is 71 %.Conclusions. The theoretical features of the surface displacement simulation are investigated and the solution of this problem is proposed based on momentum conservation law. The implementation of the proposed methodology has a four times smaller simulation error compared to the previous technique, so it can be implemented in the non-contact PAT. The residual error can be caused by the properties of the tissue, which are not taken into account in the model, which requires further research.Проблематика. Фотоакустическая томография (ФAT) является относительно новым методом диагностики, который позволяет получить изображение сетки сосудов биологической ткани неинвазивно. Этот томографический метод имеет преимущество над другими сугубо оптическими/акустическими методами благодаря большому оптическому контрасту и низким потерям энергии в тканях. Общеизвестная методика ФАТ, которая основывается на измерениях акустического давления пьезоэлектрическими датчиками, размещенными на поверхности ткани, имеет ограниченное практическое применение. В статье описана новая, полностью бесконтактная ФAT-система с полным возбуждением. Исследовано основное отличие бесконтактной ФАТ, которое состоит в измерении отклонений поверхности ткани, вызванных акустическим давлением на границе ткань–воздух.Цель исследования. Решить задачу моделирования отклонения поверхности на основе давления внутри среды, которая состоит в выводе формулы для пересчета давления в отклонение поверхности на основе закона сохранения импульса, разработке методики моделирования и сравнения ошибки предложенной методики с раннее использованной.Методика реализации. Экспериментальные данные сравниваются с промоделированным отклонением поверхности в программе k-Wave toolbox. Критерий сравнения – относительная квадратическая ошибка.Результаты исследования. Промоделированные данные отклонения поверхности на основе новой методики больше соответствуют эксперименту в сравнении с предыдущей методикой. Квадратическая ошибка новой методики составляет 18 %, предыдущей – 71 %.Выводы. В работе исследованы теоретические особенности моделирования отклонения поверхности и предложено решение этой задачи на основании закона сохранения импульса. Реализация предложенной методики имеет в четыре раза меньшую ошибку моделирования отклонения в сравнении с предыдущей методикой, поэтому она может быть реализована в бесконтактной ФАТ. Остаточная ошибка может быть обусловлена свойствами ткани, которые не учтены в модели, что требует дальнейших исследований.Проблематика. Фотоакустична томографія (ФAT) є відносно новим методом діагностики, який дає змогу отримати зображення мережі судин біологічної тканини неінвазивно. Цей томографічний метод має перевагу над іншими суто оптичними/акус­тичними методами завдяки великому оптичному контрасту і низьким втратам енергії в тканинах. Загальновідома методика ФАТ, що базується на вимірюваннях акустичного тиску п’єзоелектричними датчиками, розміщеними на поверхні тканини, має обмежене практичне використання. У статті описана нова, повністю безконтактна ФAT-система з повним збудженням. Досліджено основну відмінність безконтактної ФАТ, що полягає у вимірюванні відхилень поверхні тканини, спричинених акустичним тиском на межі тканина–повітря.Мета дослідження. Розв’язати задачу моделювання відхилення поверхні на основі тиску всередині середовища, що полягає у виведенні формули для перерахунку тиску в відхилення поверхні на основі закону збереження імпульсу, розробці методики моделювання і порівняння помилки запропонованої методики з раніше використовуваною.Методика реалізації. Експериментальні дані порівнюються з промодельованим відхиленням поверхні в програмі k-Wave toolbox. Критерій порівняння – відносна квадратична помилка.Результати дослідження. Промодельовані дані відхилення поверхні на основі нової методики більше відповідають експерименту порівняно з попередньою методикою. Квадратична помилка нової методики становить 18 %, попередньої – 71 %.Висновки. У роботі досліджено теоретичні особливості моделювання відхилення поверхні та запропоновано розв’язання цієї задачі на основі закону збереження імпульсу. Реалізація запропонованої методики має в чотири рази меншу помилку моделювання відхилення порівняно з попередньою методикою, тому вона може бути реалізована у безконтактній ФАТ. Залишкова помилка може бути спричинена властивостями тканини, які не враховані в моделі, що потребує подальших досліджень