Influence of Intermolecular Interactions on the Observable Porosity in Intrinsically Microporous Polymers

Weber, Jens,Du, Naiying,Guiver, Michael D. American Chemical Society 2011 Macromolecules Vol.44 No.7

<P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2011/mamobx.2011.44.issue-7/ma101447h/production/images/medium/ma-2010-01447h_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ma101447h'>ACS Electronic Supporting Info</A></P>

Body-centered cubic phase in 3-arm star mesogens: a torsional tapping AFM and GISAXS study

Weber, Christa H. M.,Liu, Feng,Zeng, Xiang-bing,Ungar, Goran,Mullin, Nic,Hobbs, Jamie K.,Jahr, Michael,Lehmann, Matthias The Royal Society of Chemistry 2010 SOFT MATTER Vol.6 No.21

<P>The mode of liquid crystal (LC) self-assembly of asymmetric three-arm star oligobenzoate mesogens has been investigated by torsional tapping mode AFM imaging, and by bulk and grazing-incidence X-ray diffraction. It was confirmed that the cubic liquid crystal phase has <I>Im</I>3&cmb.macr;<I>m</I> symmetry and established that it consists of spherical aggregates arranged on a body-centered lattice, rather than having a bicontinuous structure. Molecular simulation suggests that, in spite of their perceived rigidity, the oligobenzoate mesogens are folded, often sharply, within the supramolecular spheres, and that they act effectively as conical objects. The recently introduced torsional tapping AFM technique has allowed high resolution and contrast to be obtained from the soft mobile surface of the samples, showing the (110) plane of highly ordered supramolecular spheres. Notably the fine structure of the observed steps reveals that nearly isolated micelles still preserve their integrity. Finally, the equilibrium habits of the cubic LC droplets were shown by optical microscopy to be polyhedral with crystallographic facets, rather than spherical. This suggests that the air–LC interface is below the roughening transition temperature, which is attributed to the whole micelles rather than the isolated molecules acting as the interacting units.</P> <P>Graphic Abstract</P><P>A combination of torsional tapping atomic force microscopy and X-ray diffraction confirmed a cubic liquid crystal phase in 3-arm star mesogens, displaying faceted gem-like droplets and stable isolated self-assembled micelles at surface steps. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0sm00420k'> </P>

antiSMASH 3.0—a comprehensive resource for the genome mining of biosynthetic gene clusters

Weber, Tilmann,Blin, Kai,Duddela, Srikanth,Krug, Daniel,Kim, Hyun Uk,Bruccoleri, Robert,Lee, Sang Yup,Fischbach, Michael A,Mü,ller, Rolf,Wohlleben, Wolfgang,Breitling, Rainer,Takano, Eriko,Medema, Oxford University Press 2015 Nucleic acids research Vol.43 No.w1

<P><B>Abstract</B></P><P>Microbial secondary metabolism constitutes a rich source of antibiotics, chemotherapeutics, insecticides and other high-value chemicals. Genome mining of gene clusters that encode the biosynthetic pathways for these metabolites has become a key methodology for novel compound discovery. In 2011, we introduced antiSMASH, a web server and stand-alone tool for the automatic genomic identification and analysis of biosynthetic gene clusters, available at http://antismash.secondarymetabolites.org. Here, we present version 3.0 of antiSMASH, which has undergone major improvements. A full integration of the recently published ClusterFinder algorithm now allows using this probabilistic algorithm to detect putative gene clusters of unknown types. Also, a new dereplication variant of the ClusterBlast module now identifies similarities of identified clusters to any of 1172 clusters with known end products. At the enzyme level, active sites of key biosynthetic enzymes are now pinpointed through a curated pattern-matching procedure and Enzyme Commission numbers are assigned to functionally classify all enzyme-coding genes. Additionally, chemical structure prediction has been improved by incorporating polyketide reduction states. Finally, in order for users to be able to organize and analyze multiple antiSMASH outputs in a private setting, a new XML output module allows offline editing of antiSMASH annotations within the Geneious software.</P>

Dynamic Pose Tracking Accuracy Improvement via Fusing HTC Vive Trackers and Inertia Measurement Units

Mitchell Weber,Roman Hartl,Michael F. Zäh,Jihyun Lee 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.9

Virtual reality tracking devices are being investigated for application to motion tracking of robots, human bodies, indoor drones, mobile systems, etc., but most studies so far have been limited to performance analysis of commercialized tracking devices in static conditions. This paper investigated methods for improving the measurement accuracy of dynamic positioning and orientation of the HTC tracker. The signals from the photodiodes in the tracker were extracted and fused together, as well as with external Inertial Measurement Units (IMUs) signals using the Extended Kalman Filter (EKF) and the Unscented Kalman Filter (UKF). Multiple base stations, trackers and IMUs were applied to evaluate the measurement accuracy. Multiple paths were used to test different dynamic operating conditions. The results show that the proposed tracking system can improve accuracy by up to several mm by using the UKF as opposed to the EKF algorithm, increasing the number of base stations, increasing the number of trackers and fusing IMUs.

Magnetic Field Interactions of Copper-Containing Intrauterine Devices in 3.0-Tesla Magnetic Resonance Imaging: In Vivo Study

Vanessa Berger-Kulemann,Henrik Einspieler,Nilouparak Hachemian,Daniela Prayer,Siegfried Trattnig,Michael Weber,Ahmed Ba-Ssalamah 대한영상의학회 2013 Korean Journal of Radiology Vol.14 No.3

Objective: An ex vivo study found a copper-containing intrauterine device (IUD) to be safe for women undergoing an MRI examination at a 3.0-T field. No significant artifacts caused by the metallic implant were detected. However, there are still no in vivo data about these concerns. The aim of this study was to evaluate 3.0-T magnetic field interactions of copper-containing IUDs in vivo. Materials and Methods: Magnetic field interactions and potential adverse events were evaluated in 33 women using a questionnaire-based telephone survey. Two experienced radiologists performed artifact evaluation on MR images of the pelvis. Results: Eighteen patients were eligible for the survey. One patient reported a dislocation of the IUD after the MR examination. All other patients had no signs of field interactions. No IUD-related artifacts were found. Conclusion: MRI at 3.0-T is possible for women with copper-containing IUDs. However, consulting a gynecologist to check the correct position of the IUD and exclude complications after an MR examination is highly recommended. High-quality clinical imaging of the female pelvis can be performed without a loss in image quality.

Effect of flow-field structure on discharging and charging behavior of hydrogen/bromine redox flow batteries

Oh, Kyeongmin,Kang, Tae June,Park, Sungjin,Tucker, Michael C.,Weber, Adam Z.,Ju, Hyunchul Elsevier 2017 ELECTROCHIMICA ACTA Vol.230 No.-

<P><B>Abstract</B></P> <P>Designing and optimizing the flow-field structure for the liquid phase Br<SUB>2</SUB>/HBr electrolyte solution of H<SUB>2</SUB>/Br<SUB>2</SUB> redox flow batteries (RFBs) is important for improving cell performance. In this study, two electrolyte flow modes, i.e. the flow-by and flow-through modes, are simulated by using a three-dimensional H<SUB>2</SUB>/Br<SUB>2</SUB> RFB model. The model is first applied to real-scale H<SUB>2</SUB>/Br<SUB>2</SUB> cell geometries and then validated against the experimental polarization curves acquired using the two different flow modes. The model predictions compare well with the experimental data and further highlight the advantages of using the flow-through mode relative to the flow-by mode. Detailed multi-dimensional contours of the electrolyte flow velocity and key species distributions reveal that more uniform diffusion and stronger convective transport are achieved by using the flow-through mode, which alleviates the ohmic loss associated with charge transport in the Br<SUB>2</SUB> electrode.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hydrogen bromine RFB model is applied to 10cm<SUP>2</SUP> scale cell. </LI> <LI> The model is experimentally validated in the current density range up to 1.0Acm<SUP>−2</SUP>. </LI> <LI> Two different flow modes are numerically examined. </LI> <LI> The flow-through mode assures more uniform reactant profile than the flow-by mode. </LI> </UL> </P>

Brett Freedman

Maryse Fortin,Octavian Dobrescu,Peter Jarzem,Jean Ouellet,Michael H. Weber 대한척추외과학회 2018 Asian Spine Journal Vol.12 No.1

Study Design: Reliability study. Purpose: To examine the reliability of novice and experienced raters for measurements of the size and composition of the cervical extensor muscles using a thresholding technique. Overview of Literature: Although some authors have reported on the dependability of magnetic resonance imaging (MRI) measurements of the cervical muscles, there remains some variability regarding intrarater and interrater reliabilities, and few studies have examined the associated measurement error. Whether the rater’s experience noticeably influences the reliability and precision of such measurements has also not been examined. Methods: A sample of 10 patients with cervical pathologies was selected. Muscle cross-sectional area (CSA), functional crosssectional area (FCSA), and signal intensity of the cervical extensor muscles were acquired from axial T2-weighted MRIs by a novice and an experienced rater. All measurements were obtained twice, at least 5 days apart, while the raters were blinded to all earlier measurements. Results: Interrater reliability estimates (intraclass correlation coefficients) varied between 0.84 and 0.99 for the novice rater and between 0.94 and 0.99 for the experienced rater, indicating excellent reliability. The standard error of measurement for the novice rater was, however, noticeably higher for all cervical muscle measurements. Most of the interrater estimates showed excellent agreement with the exception of CSA measurement of the semispinalis cervicis at C4–C7 and FCSA measurement of the multifidus and semispinalis cervicis at C4–C7, which showed poor interrater reliability. Conclusions: The proposed method of investigating cervical muscle measurements was highly reliable; however, novice raters should receive adequate training before using this method for diagnostic, research, and clinical purposes.

Prevalence and Complications of Postoperative Transfusion for Cervical Fusion Procedures in Spine Surgery: An Analysis of 11,588 Patients from the American College of Surgeons National Surgical Quality Improvement Program Database

Ahmed Aoude,Sultan Aldebeyan,Maryse Fortin,Anas Nooh,Peter Jarzem,Jean A. Ouellet,Michael H. Weber 대한척추외과학회 2017 Asian Spine Journal Vol.11 No.6

Study Design: Retrospective cohort study. Purpose: The purpose of this study was to assess the rate of blood transfusion after cervical fusion surgery, and its effect on complication rates. Overview of Literature: Cervical spine fusions have gained interest in the literature since these procedures are now ever more frequently being performed in an outpatient setting with few complications. Methods: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify patients that underwent cervical fusion from 2010 to 2013. Multivariate regression analysis was used to determine postoperative complications associated with transfusion and cervical fusion. Results: We identified 11,588 patients who had cervical fusion between 2010 and 2013. The rate of blood transfusion following cervical fusion found to be 1.47%. All transfused patients were found to have increased risk of venous thromboembolism (TBE) (odds ratio [OR], 3.19; 95% confidence interval [95% CI], 1.16–8.77), myocardial infarction (MI) (OR, 9.12; 95% CI, 2.53–32.8), increased length of stay (LOS) (OR, 28.03; 95% CI, 14.28–55.01) and mortality (OR, 4.14; 95% CI, 1.44–11.93). Single level fusion had increased risk of TBE (OR, 3.37; 95% CI, 1.01–11.33), MI (OR, 10.5; 95% CI, 1.88–59.89), and LOS (OR, 14.79; 95% CI, 8.2–26.67). Multilevel fusion had increased risk of TBE (OR, 5.64; 95% CI, 1.15–27.6), surgical site infection (OR, 16.29; 95% CI, 3.34–79.49), MI (OR, 10.84; 95% CI, 2.01–58.55), LOS (OR, 26.56; 95% CI, 11.8–59.78), and mortality (OR, 10.24; 95% CI, 2.45–42.71). Patients who had anterior cervical discectomy and fusion surgery and received a transfusion had an increased risk of TBE (OR, 4.87; 95% CI, 1.04–22.82), surgical site infection (OR, 9.73; 95% CI, 2.14–44.1), MI (OR, 9.88; 95% CI, 1.87–52.2), increased LOS of more than 2 days (OR, 28.34; 95% CI, 13.79–58.21) and increase in mortality (OR, 6.3; 95% CI, 1.76–22.48). While, transfused patients who had posterior fusion surgery had increased risk of MI (OR, 10.45; 95% CI, 1.42–77.12) and increased LOS of more than 6 days (OR, 4.42; 95% CI, 2.68–7.29). Conclusions: Our results demonstrate that although cervical fusions can be done as outpatient procedures special precautions and investigations should be done for patients who receive transfusion after cervical fusion. These patients are demonstrated to have higher rate of MI, TBE, wound infection and mortality when compared to those who do not receive transfusion.

Postoperative Assessment of Pedicle Screws and Management of Breaches: A Survey among Canadian Spine Surgeons and a New Scoring System

Ahmed Aoude,Saber Ghadakzadeh,Hamzah Alhamzah,Maryse Fortin,Peter Jarzem,Jean A. Ouellet,Michael H. Weber 대한척추외과학회 2018 Asian Spine Journal Vol.12 No.1

Study Design: This study was designed as a survey amongst Canadian spine surgeon to determine a scoring system to standardize pedicle screw placement assessment. Purpose: This study aimed to obtain and analyze the opinions of spine surgeons regarding the assessment of pedicle screw accuracy, with the goal of establishing clinical guidelines for interventions for malpositioned pedicle screws. Overview of Literature: Accurate placement of pedicle screws is challenging, and misalignment can lead to various complications. To date, there is no recognized gold standard for assessing pedicle screw placement accuracy. The literature is lacking studies attempting to standardize pedicle screw placement accuracy assessment. Methods: A survey of the clinical methods and imaging criteria that are used for assessing pedicle screw placement accuracy was designed and sent to orthopedic and neurosurgery spine surgeons from the Canadian Spine Society for their anonymous participation. Results: Thirty-five surgeons completed the questionnaire. The most commonly used modalities for assessing pedicle screw position postoperatively were plain X-rays (97%) and computed tomography (CT, 97%). In both symptomatic and asymptomatic patients, the most and least worrisome breaches were medial and anterior breaches, respectively. The majority of surgeons tended not to re-operate on asymptomatic breaches. More than 60% of surgeons would re-operate on patients with new-onset pain and a ≤4-mm medial or inferior breach in both thoracic and lumbar regions. If a patient experienced sensory loss and a breach on CT, in either the thoracic or lumbar levels, 90% and 70% of the surgeons would re-operate for a medial breach and an inferior breach, respectively. Conclusions: Postoperative clinical presentation and imaging findings are crucial for interpreting aberrant pedicle screw placement. This study presents a preliminary scoring system for standardizing the classification of pedicle screws.