444 research outputs found

    Biogas Upgrading by Pressure Swing Adsorption

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    2-(Phenyl­carbonothio­ylsulfan­yl)acetic acid

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    The title compound, C9H8O2S2, can be used as a chain transfer agent and may be used to control the behavior of polymerization reactions. O—H⋯O hydrogen bonds of moderate character link the mol­ecules into dimers. In the crystal, the dimers are linked into sheets by C—H⋯O inter­actions, forming R 4 2(12) and R 2 2(8) edge-fused rings running parallel to [101]. There are no inter­molecular inter­actions involving the S atoms

    Nissen fundoplication for the treatment of gastroesophageal reflux disease in patients with Chagas disease without achalasia

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    Universidade Federal de SĂŁo Paulo (UNIFESP), Escola Paulista de Medicina (EPM) Department of SurgeryState University of SĂŁo Paulo Department of Surgery and OrthopedicsCatholic University of Campinas Department of SurgeryHospital do Servidor PĂșblico Estadual de SĂŁo Paulo Francisco Morato de Oliveira Department of SurgeryUNIFESP, EPM, Department of SurgerySciEL

    Gastroesophageal reflux disease in surgical versus clinical literature: clinicians do not read surgical journals

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    BACKGROUND: Several diseases may be treated either medically or surgically; however, clinical and surgical therapies are often not treated as different options for the same patient but rather as different medical philosophies. AIM: To assess whether the main surgical and medical journals make references to their counterparts, with gastroesophageal reflux as a model of clinical/surgical disease. METHOD: It was reviewed the leading medical journals in order to verify if surgeons and clinicians make references to their counterparts on their work using gastroesophageal reflux disease as a model of a clinical/surgical disease. It was reviewed the five top-ranked journals in the field of gastroenterology, general surgery and general medicine and a neutral journal. The issues of the year 2008 of the selected journals were searched for papers dealing with gastroesophageal reflux disease. RESULTS: The search in the selected journals retrieved 49 papers, 36 (74%) in clinical journals, 5 (10%) in surgical journals, 2 (4%) in general medicine journals, and 6 (12%) in the neutral journal. Thirty one (63%) had a clinical origin, 13 (26%) a surgical origin, and 5 (10%) a neutral origin. Surgical journals published only surgical papers and general medicine journals published only clinical papers. Clinical journals and general medicine journals showed a higher proportion of clinical/surgical references compared to surgical journals (p<0.001) and the neutral journal (p<0.001). There was no differences in the proportion of clinical/surgical references when surgical and the neutral journal were compared (p=0.06). Clinical journals and general medicine journals showed a similar proportion of clinical/surgical references (p=0.06). CONCLUSION: Clinicians make significantly less references to surgical journals than surgeons do to clinical journals.RACIONAL: VĂĄrias doenças podem ser tratadas mĂ©dica ou cirurgicamente; no entanto, a terapĂȘutica clĂ­nica ou cirĂșrgica nĂŁo Ă© muitas vezes usada como diferente opção para o mesmo paciente, mas sim como diferente filosofia mĂ©dica na abordagem. OBJETIVO: Verificar se os principais periĂłdicos cirĂșrgicos e clĂ­nicos fazem referĂȘncias aos seus congĂȘneres, tendo a doença do refluxo gastroesofĂĄgico como um modelo de doença clĂ­nico/cirĂșrgica. MÉTODO: Foram revistos os cinco primeiros periĂłdicos classificados na ĂĄrea de gastroenterologia, cirurgia geral e medicina geral e um jornal neutro. Os nĂșmeros do ano 2008 dos periĂłdicos selecionados foram pesquisados no como lidar com a doença do refluxo gastroesofĂĄgico. RESULTADOS: Foram selecionados 49 trabalhos, 36 (74%) em revistas clĂ­nicas, 5 (10%) em revistas de cirurgia, 2 (4%) em revistas de medicina geral e 6 (12%) no jornal neutro. Trinta e um (63%) tiveram origem clĂ­nica, 13 (26%) cirĂșrgica, e 5 (10%) a origem foi neutra. Revistas cirĂșrgicas publicaram apenas artigos cirĂșrgicos e revistas de medicina geral, publicaram apenas trabalhos clĂ­nicos. Revistas e jornais de medicina clĂ­nica geral mostraram maior proporção de referĂȘncias clĂ­nico/cirĂșrgicas em relação Ă s revistas de cirurgia (p<0,001) e do jornal neutro (p<0,001). NĂŁo houve diferenças na proporção de referĂȘncias clĂ­nico/cirĂșrgicas quando revistas cirĂșrgicas e a neutra foram comparadas (p= 0,06). Revistas clĂ­nicas e de medicina geral mostraram semelhante proporção de referĂȘncias clĂ­nico/cirĂșrgicas (p=0,06). CONCLUSÃO: Os clĂ­nicos fazem referĂȘncias significativamente menores para revistas cirĂșrgicas do que os cirurgiĂ”es fazem para as revistas clĂ­nicas.Universidade Federal de SĂŁo Paulo (UNIFESP) Escola Paulista de Medicina Departmento de CirurgiaUniversity of Chicago Department of SurgeryUNIFESP, EPM, Departmento de CirurgiaSciEL

    Effects of moderate static magnetic field on neural systems is a non-invasive mechanical stimulation of the brain possible theoretically?

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    Static magnetic fields have been shown to induce effects on the human brain. Different experiments seem to support the idea that moderate static magnetic field can exert some influence on the gating processes of the membrane channels. In this article we visit the order of magnitude of the energy magnetic terms associated with moderate applied field (between 10 and 200 milliteslas). It is shown that gradients of the Zeeman energy associated with the inhomogeneous applied fields can induce pressures of the order of 10^(-2)Pa. The surface tension generated by the magnetic pressure, on the surface delimiting the brain region subject to relevant field and gradients, is found to range between 10^(-1) and 1 mN.m^(-1). These pressures seem to be strong enough to interfere with the elastic and electrostatic energies involved in the channel activation-inactivation-deactivation mechanisms of biological membranes. It has been described that small mechanical force can activate voltage gated potassium channels. Moreover, stretch-activated ion channels are widely described in different biological tissues. Virtually, all these channels can modify their activity if stressed by a sufficient pressure delivered for enough time. We propose mechanical stimulation - possibly not exclusively - as a candidate mechanism how static magnetic field can produce effects in biological systems. It must be emphasized, that such field gradients were not previously proposed as a possible source of neural activity modification

    Comparison and evaluation of agglomerated MOFs in gaseous biofuels purification by means of pressure swing adsorption (PSA)

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    Metal-organic frameworks (MOFs) are crystalline structures consisting on metal ions coordinated to organic ligands. Porous MOFs are often formed with extremely high surface areas and other marvelous properties for adsorption processes. Although, to be used in industrial processes, MOFs should be agglomerated, being a key aspect because they properties usually are deteriorated compared with the powder [1]. Among industrial applications of adsorption, the recovery and purification of hydrogen from steam methane reforming (SMR) off-gases and the production of gaseous biofuels such as biomethane from biogas and biohydrogen have a great economic interest. Biomethane and biohydrogen could be recovered from mixtures containing carbon dioxide as main impurity by means of adsorption using pressure swing adsorption (PSA). The knowledge of the adsorption equilibrium and kinetics of the gaseous components in the targeted mixtures is the basis for the design of a PSA process for its separation.The aim of this work is the study of adsorption equilibrium and kinetics of H2, N2, CO, CH4 and CO2 on three different agglomerated MOF structures. The adsorbent performance on a typical PSA unit for hydrogen and methane purification has been evaluated by simulation. Cu-BTC, ZIF-8 and UTSA-16 MOFs have been agglomerated using the procedure described before [1]. These materials have been characterized using scanning electron microscopy (SEM), Hg porosimetry and N2 adsorption isotherm at 77K. The specific surface area of the agglomerated materials decreased less than a 5% compared with powder samples.H2, N2, CO, CH4 and CO2 high pressure equilibrium isotherms up to 50 bar at 298, 313 and 338 K have been measured and the results have been fitted using the Dual Langmuir model (table 1). Henry constants and diffusivities have been calculated using the chromatographic method described elsewhere [2]. Please click Additional Files below to see the full abstract

    CMOS nanophotonic sensor with integrated readout system

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    The measurement of nanophotonic sensors currently requires the use of external measuring equipment for their read-out such as an optical spectrum analyzer, spectrophotometer, or detectors. This requirement of external laboratory-based measuring equipment creates a “chip-in-a-lab” dilemma and hinders the use of nanophotonic sensors in practical applications. Making nanophotonic sensors usable in everyday life requires miniaturization of not only the sensor chip itself but also the equipment used for its measurement. In this paper, we have removed the need of external measuring equipment by monolithically integrating 1-D grating structures with a complementary metal-oxide-semiconductor (CMOS) integrated circuit having an array of photodiodes. By doing so, we get a direct electrical read-out of the refractive index changes induced when applying different analytes to grating structures. The gratings are made of CMOS compatible silicon nitride. Employing a nanophotonic sensor made of CMOS compatible material allows fabrication of the integrated sensor chip in a commercial CMOS foundry, enabling mass production for commercialization with low cost. Our results present a significant step toward transforming present laboratory-based nanophotonic sensors into practical portable devices to enable applications away from the analytical laboratory. We anticipate the work will have a major impact on technology for personalized medicine, environmental, and industrial sensing

    Unraveling structural and compositional information in 3D FinFET electronic devices

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    Non-planar Fin Field Effect Transistors (FinFET) are already present in modern devices. The evolution from the well-established 2D planar technology to the design of 3D nanostructures rose new fabrication processes, but a technique capable of full characterization, particularly their dopant distribution, in a representative (high statistics) way is still lacking. Here we propose a methodology based on Medium Energy Ion Scattering (MEIS) to address this query, allowing structural and compositional quantification of advanced 3D FinFET devices with nanometer spatial resolution. When ions are backscattered, their energy losses unfold the chemistry of the different 3D compounds present in the structure. The FinFET periodicity generates oscillatory features as a function of backscattered ion energy and, in fact, these features allow a complete description of the device dimensions. Additionally, each measurement is performed over more than thousand structures, being highly representative in a statistical meaning. Finally, independent measurements using electron microscopy corroborate the proposed methodolog
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