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Oliver Berberich,Julia Blöhbaum,Stefanie Hölscher-Doht,Rainer H. Meffert,Jörg Teßmar,Torsten Blunk,Jürgen Groll 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-
Tissue adhesives play an important role in clinical applications and may aid in the treatment of cartilagedefects for improved cartilage integration. However, many fail to satisfy the demand for adequateadhesive strength on wet tissue surfaces and to facilitate sufficient cell migration and extracellular matrix(ECM) deposition at the defect site. Utilizing poly(2-alkyl-2-oxazoline) (POx)-based polymers equippedwith mussel-inspired adhesion moieties and combining them with the natural wound sealantfibrinogen,we fabricated an adhesive biosynthethic hydrogel with tunable mechanical properties and improvedbonding strength. Degradation of the hydrogels could be adjusted by the ratio of amide to ester linkagesof the catecholic functional group at the POx side chain. In an in vitro disc/ring model for lateral cartilageintegration, a benefit in long-term integration was observed with enhanced degradation of the adhesivewithout the expense of bonding strength. Incorporation of degradable ester linkages in the polymerfacilitated cell invasion and strong deposition of cartilaginous ECM at the defect site. Overall, the resultssuggest that the presented injectable adhesive hydrogel, due to its easy tunability, holds great potentialfor cartilage defect treatment and other medical applications.
CAR links hypoxia signaling to improved survival after myocardial infarction
Freiberg Fabian,Thakkar Meghna,Hamann Wiebke,Jacobo Lopez Carballo,Jüttner Rene,Voss Felizia K.,Becher Peter M.,Westermann Dirk,Tschöpe Carsten,Heuser Arnd,Rocks Oliver,Robert Fischer,Gotthardt Michae 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-
The coxsackievirus and adenovirus receptor (CAR) mediates homo- and heterotopic interactions between neighboring cardiomyocytes at the intercalated disc. CAR is upregulated in the hypoxic areas surrounding myocardial infarction (MI). To elucidate whether CAR contributes to hypoxia signaling and MI pathology, we used a gain- and loss-of-function approach in transfected HEK293 cells, H9c2 cardiomyocytes and CAR knockout mice. CAR overexpression increased RhoA activity, HIF-1α expression and cell death in response to chemical and physical hypoxia. In vivo, we subjected cardiomyocyte-specific CAR knockout (KO) and wild-type mice (WT) to coronary artery ligation. Survival was drastically improved in KO mice with largely preserved cardiac function as determined by echocardiography. Histological analysis revealed a less fibrotic, more compact lesion. Thirty days after MI, there was no compensatory hypertrophy or reduced cardiac output in hearts from CAR KO mice, in contrast to control mice with increased heart weight and reduced ejection fraction as signs of the underlying pathology. Based on these findings, we suggest CAR as a therapeutic target for the improved future treatment or prevention of myocardial infarction.
Julius Moratin,Moritz Berger,Thomas Rückschloss,Karl Metzger,Hannah Berger,Maximilian Gottsauner,Michael Engel,Jürgen Hoffmann,Christian Freudlsperger,Oliver Ristow 대한영상치의학회 2020 Imaging Science in Dentistry Vol.50 No.3
Purpose: Image artifacts caused by patient motion cause problems in cone-beam computed tomography (CBCT) because they lead to distortion of the 3-dimensional reconstruction. This prospective study was performed to quantify patient movement during CBCT acquisition and its influence on image quality. Materials and Methods: In total, 412 patients receiving CBCT imaging were equipped with a wireless head sensor system that detected inertial, gyroscopic, and magnetometric movements with 6 dimensions of freedom. The type and amplitude of movements during CBCT acquisition were evaluated and image quality was rated in 7 different anatomical regions of interest. For continuous variables, significance was calculated using the Student t-test. A linear regression model was applied to identify associations of the type and extent of motion with image quality scores. Kappa statistics were used to assess intra- and inter-rater agreement. Chi-square testing was used to analyze the impact of age and sex on head movement. Results: All CBCT images were acquired in a 10-month period. In 24% of the investigations, movement was recorded (acceleration: >0.10 [m/s2]; angular velocity: >0.018 [°/s]). In all examined regions of interest, head motion during CBCT acquisition resulted in significant impairment of image quality (P<0.001). Movement in the horizontal and vertical axes was most relevant for image quality (R2>0.7). Conclusion: Relevant head motions during CBCT imaging were frequently detected, leading to image quality loss and potentially impairing diagnosis and therapy planning. The presented data illustrate the need for digital correction algorithms and hardware to minimize motion artefacts in CBCT imaging
A size dependent evaluation of the cytotoxicity and uptake of nanographene oxide
Mendes, Rafael Gregorio,Koch, Britta,Bachmatiuk, Alicja,Ma, Xing,Sanchez, Samuel,Damm, Christine,Schmidt, Oliver G.,Gemming, Thomas,Eckert, Jü,rgen,Rü,mmeli, Mark H. The Royal Society of Chemistry 2015 Journal of Materials Chemistry B Vol.3 No.12
<P>Graphene oxide (GO) has attracted great interest due to its extraordinary potential for biomedical application. Although it is clear that the naturally occurring morphology of biological structures is crucial to their precise interactions and correct functioning, the geometrical aspects of nanoparticles are often ignored in the design of nanoparticles for biological applications. A few <I>in vitro</I> and <I>in vivo</I> studies have evaluated the cytotoxicity and biodistribution of GO, however very little is known about the influence of flake size and cytotoxicity. Herein, we aim at presenting an initial cytotoxicity evaluation of different nano-sized GO flakes for two different cell lines (HeLa (Kyoto) and macrophage (J7742)) when they are exposed to samples containing different sized nanographene oxide (NGO) flakes (mean diameter of 89 and 277 nm). The obtained data suggests that the larger NGO flakes reduce cell viability as compared to smaller flakes. In addition, the viability reduction correlates with the time and the concentration of the NGO nanoparticles to which the cells are exposed. Uptake studies were also conducted and the data suggests that both cell lines internalize the GO nanoparticles during the incubation periods studied.</P>
Evaluation of Resolution Improvement Ability of a DSP Technique for Filter-Array-Based Spectrometers
Oliver, J.,Lee, Woong-Bi,Park, Sang-Jun,Lee, Heung-No The Korea Institute of Information and Commucation 2013 韓國通信學會論文誌 Vol.38 No.6C
In this paper, we aim to evaluate the performance of the digital signal processing (DSP) algorithm used in [8] in order to improve the resolution of spectrometers with fixed number of low-cost, non-ideal filters. In such spectrometers, the resolution is limited by the number of filters. We aim to demonstrate via new experiments that the resolution improvement by six times over the conventional limit is possible by using the DSP algorithm as claimed by [8].
Filters with random transmittance for improving resolution in filter-array-based spectrometers.
Oliver, J,Lee, Woong-Bi,Lee, Heung-No Optical Society of America 2013 Optics express Vol.21 No.4
<P>In this paper, we introduce a method for improving the resolution of miniature spectrometers. Our method is based on using filters with random transmittance. Such filters sense fine details of an input signal spectrum, which, when combined with a signal processing algorithm, aid in improving resolution. We also propose an approach for designing filters with random transmittance using optical thin-film technology. We demonstrate that the improvement in resolution is 7-fold when using the filters with random transmittance over what was achieved in our previous work.</P>
Olive, P.L.,Banuelos, C.A.,Durand, R.E.,Kim, J.Y.,Aquino-Parsons, C. Elsevier Science Publishers 2010 Radiotherapy and oncology Vol.94 No.1
<P>Background and purpose: The possibility of using gamma H2AX foci as a marker of DNA damage and as a potential predictor of turnout, response to treatment was examined using biopsies from 3 sets of patients with advanced carcinoma of the cervix. The relation between endogenous gamma H2AX expression and hypoxia was also examined. Materials and methods: Set I consisted of 26 biopsies that included pre-treatment and 24 h post-radiation treatment samples. Pre-treatment biopsies from 12 patients in Set 2 were used to develop image analysis Software while pre-treatment biopsies from 33 patients in Set 3 were examined for the relation between staining for the hypoxia marker pimonidazole and endogenous gamma H2AX expression. Formalin-fixed paraffin-embedded sections were analyzed after antigen retrieval and fluorescence antibody labeling for the hypoxia markers CAIX or pimonidazole in combination with gamma H2AX staining. Results: Before treatment, 24 +/- 19% of cells contained gamma H2AX foci, with most positive cells containing fewer than 5 foci per nucleus. Twenty-four hours after exposure to the first fraction of 1.8-2.5 Gy. 38 +/- 19% contained foci. CAIX positive cells were 1.4 times more likely to exhibit endogenous gamma H2AX foci, and pimonidazole-positive cells were 2.8 times more likely to contain gamma H2AX foci. For 18 patients for whom both pre-treatment and 24 h post-irradiation biopsies were available, local control was unrelated to the fraction of cells that retained gamma H2AX foci. However, 24 h after irradiation, tumours that had received 2.5 Gy showed a significantly higher fraction of cells with residual gamma H2AX foci than tumours given 1.8 Gy. Conclusions: Endogenous gamma H2AX foci are enriched in hypoxic tumour regions. Small differences in delivered dose can produce quantifiable differences in residual DNA damage that can overshadow inter-tumour differences in response. (C) 2009 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 94 (2010) 82-89</P>
Improving resolution of miniature spectrometers by exploiting sparse nature of signals.
Oliver, J,Lee, Woongbi,Park, Sangjun,Lee, Heung-No Optical Society of America 2012 Optics express Vol.20 No.3
<P>In this paper, we present a signal processing approach to improve the resolution of a spectrometer with a fixed number of low-cost, non-ideal filters. We aim to show that the resolution can be improved beyond the limit set by the number of filters by exploiting the sparse nature of a signal spectrum. We consider an underdetermined system of linear equations as a model for signal spectrum estimation. We design a non-negative L1 norm minimization algorithm for solving the system of equations. We demonstrate that the resolution can be improved multiple times by using the proposed algorithm.</P>
Oliver-Calixte, Nyoté,J.,Uba, Franklin I.,Battle, Katrina N.,Weerakoon-Ratnayake, Kumuditha M.,Soper, Steven A. American Chemical Society 2014 ANALYTICAL CHEMISTRY - Vol.86 No.9
<P>The process of immobilizing enzymes onto solid supports for bioreactions has some compelling advantages compared to their solution-based counterpart including the facile separation of enzyme from products, elimination of enzyme autodigestion, and increased enzyme stability and activity. We report the immobilization of λ-exonuclease onto poly(methylmethacrylate) (PMMA) micropillars populated within a microfluidic device for the on-chip digestion of double-stranded DNA. Enzyme immobilization was successfully accomplished using 3-(3-dimethylaminopropyl) carbodiimide/<I>N</I>-hydroxysuccinimide (EDC/NHS) coupling to carboxylic acid functionalized PMMA micropillars. Our results suggest that the efficiency for the catalysis of dsDNA digestion using λ-exonuclease, including its processivity and reaction rate, were higher when the enzyme was attached to a solid support compared to the free solution digestion. We obtained a clipping rate of 1.0 × 10<SUP>3</SUP> nucleotides s<SUP>–1</SUP> for the digestion of λ-DNA (48.5 kbp) by λ-exonuclease. The kinetic behavior of the solid-phase reactor could be described by a fractal Michaelis–Menten model with a catalytic efficiency nearly 17% better than the homogeneous solution-phase reaction. The results from this work will have important ramifications in new single-molecule DNA sequencing strategies that employ free mononucleotide identification.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancham/2014/ancham.2014.86.issue-9/ac5002965/production/images/medium/ac-2014-002965_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ac5002965'>ACS Electronic Supporting Info</A></P>