Kinetics of Mixing-Assisted Oxidative Desulfurization of Dibenzothiophene in Toluene Using a Phosphotungstic Acid/Hydrogen Peroxide System: Effects of Operating Conditions

de Luna, Mark Daniel G.,Wan, Meng-Wei,Golosinda, Lucille R.,Futalan, Cybelle M.,Lu, Ming-Chun ACS AMERICAN CHEMICAL SOCIETY 2017 ENERGY AND FUELS Vol.31 No.9

<P>Mixing-assisted oxidative desulfurization (MAOD) of model fuel that contains dibenzothiophene (DBT) using phosphotungstic acid (HPW) as a catalyst and hydrogen peroxide (H2O2) as an oxidant was evaluated. Characterization analysis of HPW shows that the average crystallite size is 82.39 nm, with a disintegrated structure and morphology. The effect of operating parameters, such as mixer speed (5000-10 000 rpm), tetraoctylammoniurn bromide [phase-transfer agent (PTA)]/HPW ratio (0.5:1-5:1), and temperature (25-60 degrees C), on the sulfur conversion of DBT was examined. Results show that the sulfur conversion increases with an increasing temperature and mixer speed and a lower amount of PTA. The highest sulfur removal and rate constant of 100.0% and 0.1528 min(-1), respectively, were attained under the following conditions: 1:1 ratio, 40 degrees C, and 10 000 rpm. The pseudo-first-order equation and Arrhenius equation were applied to determine the kinetic rate constant and activation energy of HPW in the oxidation of DBT in a MAOD system. High correlation coefficient values (R-2 >= 0.93) indicate that the pseudo-first-order equation has the goodness of fit in describing the experimental kinetic data. Moreover, the activation energy of HPW derived from the Arrhenius equation was 42.60 kJ/mol.</P>

Graphene: Piecing it Together

Rü,mmeli, Mark H.,Rocha, Claudia G.,Ortmann, Frank,Ibrahim, Imad,Sevincli, Haldun,Bö,rrnert, Felix,Kunstmann, Jens,Bachmatiuk, Alicja,Pö,tschke, Markus,Shiraishi, Masashi,Meyyappan, M.,B&u WILEY‐VCH Verlag 2011 ADVANCED MATERIALS Vol.23 No.39

<P><B>Abstract</B></P><P>Graphene has a multitude of striking properties that make it an exceedingly attractive material for various applications, many of which will emerge over the next decade. However, one of the most promising applications lie in exploiting its peculiar electronic properties which are governed by its electrons obeying a linear dispersion relation. This leads to the observation of half integer quantum hall effect and the absence of localization. The latter is attractive for graphene‐based field effect transistors. However, if graphene is to be the material for future electronics, then significant hurdles need to be surmounted, namely, it needs to be mass produced in an economically viable manner and be of high crystalline quality with no or virtually no defects or grains boundaries. Moreover, it will need to be processable with atomic precision. Hence, the future of graphene as a material for electronic based devices will depend heavily on our ability to piece graphene together as a single crystal and define its edges with atomic precision. In this progress report, the properties of graphene that make it so attractive as a material for electronics is introduced to the reader. The focus then centers on current synthesis strategies for graphene and their weaknesses in terms of electronics applications are highlighted.</P>

Propagation Characteristics of Fasting Duodeno-Jejunal Contractions in Healthy Controls Measured by Clustered Closely-spaced Manometric Sensors

Jason R Baker,Joseph R Dickens,Mark Koenigsknecht,Ann Frances,Allen A Lee,Kerby A Shedden,James G Brasseur,Gordon L Amidon,Duxin Sun,William L Hasler 대한소화기 기능성질환∙운동학회 2019 Journal of Neurogastroenterology and Motility (JNM Vol.25 No.1

Background/Aims High-resolution methods have advanced esophageal and anorectal manometry interpretation but are incompletely established for intestinal manometry. We characterized normal fasting duodeno-jejunal manometry parameters not measurable by standard techniques using clustered closely-spaced recordings. Methods Ten fasting recordings were performed in 8 healthy controls using catheters with 3–4 gastrointestinal manometry clusters with 1–2 cm channel spacing. Migrating motor complex phase III characteristics were quantified. Spatial-temporal contour plots measured propagation direction and velocity of individual contractions. Coupling was defined by pressure peak continuity within clusters. Results Twenty-three phase III complexes (11 antral, 12 intestinal origin) with 157 (95% CI, 104–211) minute periodicities, 6.99 (6.25–7.74) minute durations, 10.92 (10.68–11.16) cycle/minute frequencies, 73.6 (67.7–79.5) mmHg maximal amplitudes, and 4.20 (3.18–5.22) cm/minute propagation velocities were recorded. Coupling of individual contractions was 39.1% (32.1–46.1); 63.0% (54.4–71.6) of contractions were antegrade and 32.8% (24.1–41.5) were retrograde. Individual phase III contractions propagated > 35 fold faster (2.48 cm/sec; 95% CI, 2.25–2.71) than complexes themselves. Phase III complexes beyond the proximal jejunum were longer in duration (P = 0.025) and had poorer contractile coupling (P = 0.025) than proximal complexes. Coupling was greater with 1 cm channel spacing vs 2 cm (P < 0.001). Conclusions Intestinal manometry using clustered closely-spaced pressure ports characterizes novel antegrade and retrograde propagation and coupling properties which degrade in more distal jejunal segments. Coupling is greater with more closely-spaced recordings. Applying similar methods to dysmotility syndromes will define the relevance of these methods.

Management of complex surgical wounds of the back: identifying an evidence-based approach

Elizabeth G. Zolper,Meher A. Saleem,Kevin G. Kim,Mark D. Mishu,Sarah R. Sher,Christopher E. Attinger,Kenneth L. Fan,Karen K. Evans 대한성형외과학회 2021 Archives of Plastic Surgery Vol.48 No.6

Background Postoperative dehiscence and surgical site infection after spinal surgery can carry serious morbidity. Multidisciplinary involvement of plastic surgery is essential to minimizing morbidity and achieving definitive closure. However, a standardized approach is lacking. The aim of this study was to identify effective reconstructive interventions for the basis of an evidence-based management protocol. Methods A retrospective review was performed at a single tertiary institution for 45 patients who required 53 reconstruction procedures with plastic surgery for wounds secondary to spinal surgery from 2010 to 2019. Statistical analysis was performed for demographics, comorbidities, and treatment methods. Primary outcomes were postoperative complications, including dehiscence, seroma, and infection. The secondary outcome was time to healing. Results The overall complication rate was 32%, with dehiscence occurring in 17%, seroma in 15% and infection in 11% of cases. Median follow-up was 10 months (interquartile range, 4–23). Use of antibiotic beads did not affect rate of infection occurrence after wound closure (P=0.146). Use of incisional negative pressure wound therapy (iNPWT) was significant for reduced time to healing (P=0.001). Patients treated without iNPWT healed at median of 67.5 days while the patients who received iNPWT healed in 33 days. Demographics and comorbidities between these two groups were similar. Conclusions This data provides groundwork for an evidence-based approach to soft tissue reconstruction and management of dehiscence after spinal surgery. Timely involvement of plastic surgery in high-risk patients and utilization of evidence-based interventions such as iNPWT are essential for improving outcomes in this population.

Typhoid conjugate vaccines: a new tool in the fight against antimicrobial resistance

Andrews, Jason R,Baker, Stephen,Marks, Florian,Alsan, Marcella,Garrett, Denise,Gellin, Bruce G,Saha, Samir K,Qamar, Farah Naz,Yousafzai, Mohammad Tahir,Bogoch, Isaac I,Antillon, Marina,Pitzer, Virgini ELSEVIER 2019 LANCET INFECTIOUS DISEASES Vol.19 No.1

<P><B>Summary</B></P> <P>Typhoid fever is an acute systemic infectious disease responsible for an estimated 12–20 million illnesses and over 150 000 deaths annually. In March, 2018, a new recommendation was issued by WHO for the programmatic use of typhoid conjugate vaccines in endemic countries. Health economic analyses of typhoid vaccines have informed funding decisions and national policies regarding vaccine rollout. However, by focusing only on averted typhoid cases and their associated costs, traditional cost-effectiveness analyses might underestimate crucial benefits of typhoid vaccination programmes, because the potential effect of typhoid vaccines on the treatment of patients with non-specific acute febrile illnesses is not considered. For every true case of typhoid fever, three to 25 patients without typhoid disease are treated with antimicrobials unnecessarily, conservatively amounting to more than 50 million prescriptions per year. Antimicrobials for suspected typhoid might therefore be an important selective pressure for the emergence and spread of antimicrobial resistance globally. We propose that large-scale, more aggressive typhoid vaccination programmes—including catch-up campaigns in children up to 15 years of age, and vaccination in lower incidence settings—have the potential to reduce the overuse of antimicrobials and thereby reduce antimicrobial resistance in many bacterial pathogens. Funding bodies and national governments must therefore consider the potential for broad reductions in antimicrobial use and resistance in decisions related to the rollout of typhoid conjugate vaccines.</P>

UV Star Formation Rates in the Local Universe

Salim, Samir,Rich, R. Michael,Charlot, Stephane,Brinchmann, Jarle,Johnson, Benjamin D.,Schiminovich, David,Seibert, Mark,Mallery, Ryan,Heckman, Timothy M.,Forster, Karl,Friedman, Peter G.,Martin, D. C IOP Publishing 2007 The Astrophysical journal, Supplement series Vol.173 No.2

Characterization of a New Metallo-β-Lactamase Gene, blaNDM-1, and a Novel Erythromycin Esterase Gene Carried on a Unique Genetic Structure in Klebsiella pneumoniae Sequence Type 14 from India

Yong, Dongeun,Toleman, Mark A.,Giske, Christian G.,Cho, Hyun S.,Sundman, Kristina,Lee, Kyungwon,Walsh, Timothy R. American Society for Microbiology 2009 Antimicrobial Agents and Chemotherapy Vol.53 No.12

<B>ABSTRACT</B><P>A Swedish patient of Indian origin traveled to New Delhi, India, and acquired a urinary tract infection caused by a carbapenem-resistant <I>Klebsiella pneumoniae</I> strain that typed to the sequence type 14 complex. The isolate, <I>Klebsiella pneumoniae</I> 05-506, was shown to possess a metallo-β-lactamase (MBL) but was negative for previously known MBL genes. Gene libraries and amplification of class 1 integrons revealed three resistance-conferring regions; the first contained <I>bla</I>CMY-4 flanked by IS<I>EcP1</I> and <I>blc</I>. The second region of 4.8 kb contained a complex class 1 integron with the gene cassettes <I>arr</I>-<I>2</I>, a new erythromycin esterase gene; <I>ereC</I>; <I>aadA1</I>; and <I>cmlA7</I>. An intact IS<I>CR1</I> element was shown to be downstream from the <I>qac</I>/<I>sul</I> genes. The third region consisted of a new MBL gene, designated <I>bla</I>NDM-1, flanked on one side by <I>K. pneumoniae</I> DNA and a truncated IS<I>26</I> element on its other side. The last two regions lie adjacent to one another, and all three regions are found on a 180-kb region that is easily transferable to recipient strains and that confers resistance to all antibiotics except fluoroquinolones and colistin. NDM-1 shares very little identity with other MBLs, with the most similar MBLs being VIM-1/VIM-2, with which it has only 32.4% identity. As well as possessing unique residues near the active site, NDM-1 also has an additional insert between positions 162 and 166 not present in other MBLs. NDM-1 has a molecular mass of 28 kDa, is monomeric, and can hydrolyze all β-lactams except aztreonam. Compared to VIM-2, NDM-1 displays tighter binding to most cephalosporins, in particular, cefuroxime, cefotaxime, and cephalothin (cefalotin), and also to the penicillins. NDM-1 does not bind to the carbapenems as tightly as IMP-1 or VIM-2 and turns over the carbapenems at a rate similar to that of VIM-2. In addition to <I>K. pneumoniae</I> 05-506, <I>bla</I>NDM-1 was found on a 140-kb plasmid in an <I>Escherichia coli</I> strain isolated from the patient's feces, inferring the possibility of in vivo conjugation. The broad resistance carried on these plasmids is a further worrying development for India, which already has high levels of antibiotic resistance.</P>

Insights into the Early Growth of Homogeneous Single-Layer Graphene over Ni–Mo Binary Substrates

Rü,mmeli, Mark H.,Zeng, Mengqi,Melkhanova, Svetlana,Gorantla, Sandeep,Bachmatiuk, Alicja,Fu, Lei,Yan, Chenglin,Oswald, Steffen,Mendes, Rafael G.,Makarov, Denys,Schmidt, Oliver,Eckert, Jü,r American Chemical Society 2013 Chemistry of materials Vol.25 No.19

<P>The employment of Ni–Mo films has recently been shown to yield strictly homogeneous single-layer graphene. In this study, we systematically investigate the different stages of nucleation and growth of graphene over Ni–Mo layers. The studies reveal that the Ni film breaks up and diffuses into the underlying Mo foil, forming a Ni–Mo intermetallic. Nucleation only occurs from Ni sites, and thus, the nucleation density can be controlled by the Ni film thickness. Both nucleation and growth of the graphene are shown to be susceptible to very efficient self-termination processes to the formation of molybdenum carbide, and this guarantees the formation of large area graphene that consists <I>entirely</I> of monolayer graphene.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2013/cmatex.2013.25.issue-19/cm4020783/production/images/medium/cm-2013-020783_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm4020783'>ACS Electronic Supporting Info</A></P>

The Role of Inflammatory Mediators in the Pathogenesis of Otitis Media and Sequelae

Steven K. Juhn,정민교,Mark D. Hoffman,Brian R. Drew,Diego A. Preciado,Nicholas J. Sausen,Timothy T.K. Jung,Bo Hyung Kim,박상유,Jizhen Lin,Frank G. Ondrey,David R. Mains,Tina Huang 대한이비인후과학회 2008 Clinical and Experimental Otorhinolaryngology Vol.1 No.3

This review deals with the characteristics of various inflammatory mediators identified in the middle ear during otitis media and in cholesteatoma. The role of each inflammatory mediator in the pathogenesis of otitis media and cholesteatoma has been discussed. Further, the relation of each inflammatory mediator to the pathophysiology of the middle and inner ear along with its mechanisms of pathological change has been described. The mechanisms of hearing loss including sensorineural hearing loss (SNHL) as a sequela of otitis media are also discussed. The passage of inflammatory mediators through the round window membrane into the scala tympani is indicated. In an experimental animal model, an application of cytokines and lipopolysaccharide (LPS), a bacterial toxin, on the round window membrane induced sensorineural hearing loss as identified through auditory brainstem response threshold shifts. An increase in permeability of the blood-labyrinth barrier (BLB) was observed following application of these inflammatory mediators and LPS. The leakage of the blood components into the lateral wall of the cochlea through an increase in BLB permeability appears to be related to the sensorineural hearing loss by hindering K+ recycling through the lateral wall disrupting the ion homeostasis of the endolymph. Further studies on the roles of various inflammatory mediators and bacterial toxins in inducing the sensorineumral hearing loss in otitis media should be pursued.

Microwave-driven coherent operation of a semiconductor quantum dot charge qubit.

Kim, Dohun,Ward, D R,Simmons, C B,Gamble, John King,Blume-Kohout, Robin,Nielsen, Erik,Savage, D E,Lagally, M G,Friesen, Mark,Coppersmith, S N,Eriksson, M A Nature Pub. Group 2015 Nature nanotechnology Vol.10 No.3

<P>An intuitive realization of a qubit is an electron charge at two well-defined positions of a double quantum dot. This qubit is simple and has the potential for high-speed operation because of its strong coupling to electric fields. However, charge noise also couples strongly to this qubit, resulting in rapid dephasing at all but one special operating point called the 'sweet spot'. In previous studies d.c. voltage pulses have been used to manipulate semiconductor charge qubits but did not achieve high-fidelity control, because d.c. gating requires excursions away from the sweet spot. Here, by using resonant a.c. microwave driving we achieve fast (greater than gigahertz) and universal single qubit rotations of a semiconductor charge qubit. The Z-axis rotations of the qubit are well protected at the sweet spot, and we demonstrate the same protection for rotations about arbitrary axes in the X-Y plane of the qubit Bloch sphere. We characterize the qubit operation using two tomographic approaches: standard process tomography and gate set tomography. Both methods consistently yield process fidelities greater than 86% with respect to a universal set of unitary single-qubit operations.</P>