Assessment of postoperative nausea and vomiting after bariatric surgery using a validated questionnaire

BACKGROUND: Postoperative nausea and vomiting (PONV) is known to occur after bariatric surgery, with over two thirds of patients affected. However, variability exists in how to objectively measure PONV. OBJECTIVES: The goals of the present study were to use a validated, patient-centered scoring tool, the Rhodes Index of Nausea, Vomiting, and Retching to measure the severity of PONV after bariatric surgery, to directly compare PONV between patients who underwent laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (LRYGB), and to identify risk factors for the development of PONV after bariatric surgery. SETTING: Barnes-Jewish Hospital/Washington University School of Medicine, St. Louis, Missouri, United States of America. METHODS: The Washington University Weight Loss Surgery team prospectively surveyed patients from January 1, 2017 to December 1, 2018 at the following 6 different timepoints: postoperative day (POD) 0, POD 1, POD 2, POD 3 to 4, the first postoperative outpatient visit (POV 1: POD 5-25), and the second postoperative visit (POV 2: POD 25-50). At each timepoint, a cumulative Rhodes score was calculated from the sum of 8 questions. The American Society for Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database was used to collect patient demographic characteristics and perioperative clinical data. RESULTS: A total of 274 patients met study criteria and completed 605 Rhodes questionnaires. Two hundred fifty Rhodes questionnaires were completed by patients after SG and 355 were completed by patients after LRYGB. Total Rhodes scores are statistically higher in LSG patients compared with patients who underwent LRYGB (LSG = 5.45 ± 6.27; LRYGB = 3.08 ± 4.19, P = .0002). Additionally, at the earlier timepoints, scores were higher among patients who underwent LSG than those who had undergone LRYGB as follows: POD 0 (LSG = 6.96 ± 6.50; LRYGB = 2.89 ± 2.90, P = .0115), POD 1 (LSG = 8.20 ± 6.76; LRYGB = 2.88 ± 3.44, P \u3c .0001), and POD 2 (LSG = 4.05 ± 4.88; LRYGB = 2.06 ± 3.43, P = .05). On subset analysis, examining patients who either underwent an LSG or LRYGB, both procedures had a statistically significant PONV peak emerge on POV 2. Last, overall Rhodes scores were statistically higher in female patients compared with male patients (female: 4.43 ± 5.46; male: 2.35 ± 3.90, P = .021). Although the magnitude of the difference varied somewhat across POD time intervals, the difference was most pronounced at POV 2. CONCLUSIONS: This is the largest study using a validated nausea and vomiting questionnaire to objectively measure PONV after bariatric surgery. The factors found to be most associated with increased PONV were LSG and female sex. Ultimately, these data can help bariatric surgery programs, including Washington University Weight Loss Surgery, identify patients who may require more intensive treatment of PONV, particularly POD 0 to 2, and help to identify patients that continue to struggle with PONV in the later surgical recovery phase

Progressive induction of left ventricular pressure overload in a large animal model elicits myocardial remodeling and a unique matrix signature

ObjectivePatients with severe left ventricular pressure overload secondary to aortic stenosis can present with signs and symptoms of heart failure despite normal left ventricular ejection fraction. This process occurs, at least in part, as a result of left ventricular pressure overload–induced extracellular matrix remodeling that promulgates increased left ventricular stiffness and impaired diastolic function. However, the determinants that drive extracellular matrix remodeling in this form of left ventricular pressure overload remain to be fully defined.MethodsLeft ventricular pressure overload was induced in mature pigs (n = 15) by progressive ascending aortic cuff inflation (once per week for 4 weeks), whereby left ventricular mass, left ventricular ejection fraction, and regional myocardial stiffness (rKm) were compared with referent controls (n = 12). Determinants of extracellular matrix remodeling were assessed by measuring levels of mRNA expression for fibrillar collagens, matrix metalloproteinases, and tissue inhibitors of matrix metalloproteinase 1 and 4.ResultsWith left ventricular pressure overload, left ventricular mass and rKm increased by 2- and 3-fold, respectively, compared with control, with no change in left ventricular ejection fraction. Left ventricular myocardial collagen increased approximately 2-fold, which was accompanied by reduced solubility (ie, increased cross-linking) with left ventricular pressure overload, but mRNA expression for fibrillar collagen and matrix metalloproteinases remained relatively unchanged. In contrast, a robust increase in mRNA expression for tissue inhibitors of matrix metalloproteinase-1 and 4 occurred with left ventricular pressure overload.ConclusionsIn a progressive model of left ventricular pressure overload, which recapitulates the phenotype of aortic stenosis, increased extracellular matrix accumulation and subsequently increased myocardial stiffness were not due to increased fibrillar collagen expression but rather to determinants of post-translational control that included increased collagen stability (thereby resistant to matrix metalloproteinase degradation) and increased endogenous matrix metalloproteinase inhibition. Targeting these extracellular matrix post-translational events with left ventricular pressure overload may hold both diagnostic and therapeutic relevance

Integrable microwave filter based on a photonic crystal delay line

The availability of a tunable delay line with a chip-size footprint is a crucial step towards the full implementation of integrated microwave photonic signal processors. Achieving a large and tunable group delay on a millimetre-sized chip is not trivial. Slow light concepts are an appropriate solution, if propagation losses are kept acceptable. Here we use a low-loss 1.5 mm-long photonic crystal waveguide to demonstrate both notch and band-pass microwave filters that can be tuned over the 0 50-GHz spectral band. The waveguide is capable of generating a controllable delay with limited signal attenuation (total insertion loss below 10 dB when the delay is below 70 ps) and degradation. Owing to the very small footprint of the delay line, a fully integrated device is feasible, also featuring more complex and elaborate filter functions.This work was funded by the European Union under the project GOSPEL (grant 219299) and by the Valencian Government (Prometeo GVA 2008-92). We thank S. Hughes and P. Lalanne for enlightening discussion about the impact of disorder in photonic crystal waveguides.Sancho Durá, J.; Bourderionnet, J.; Lloret Soler, JA.; Combrie, S.; Gasulla Mestre, I.; Xavier, S.; Sales Maicas, S.... (2012). Integrable microwave filter based on a photonic crystal delay line. Nature Communications. 3:1-9. https://doi.org/10.1038/ncomms2092S193Seeds, A. Microwave photonics. IEEE Trans. Microwave Theory Tech. 50, 877–887 (2002).Capmany, J. & Novak, D. Microwave photonics combines two worlds. Nat. Photon 1, 319–330 (2007).Yao, J. P. Microwave photonics. J. Lightwave Technol. 27, 314–335 (2009).See special technology focus on microwave photonics. Nat. Photon 5, 723–736 (2011).Capmany, J., Ortega, B. & Pastor, D. A tutorial on microwave photonic filters. J. Lightwave. Technol. 24, 201–229 (2006).Long, J. et al. A tunable microstrip bandpass filter with two independently adjustable transmission zeros. IEEE Microw. Wireless Compon. Lett. 21, 74–76 (2011).Velez, A. et al. Tunable coplanar waveguide band-stop and band-pass filters based on open split ring resonators and open complementary split ring resonators. IEEE Microw. Antennas Propag. 5, 277–281 (2011).Sekar, V., Armendariz, M. & Entesari, K. A 1.2-1.6-GHz substrate-integrated-waveguide RF MEMS tunable filter. IEEE Trans. Microwave Theory Tech. 59, 866–876 (2011).Rafique, M. R. et al. Miniaturized superconducting microwave filters. Supercond. Sci. Technol. 21, 075004 (2008).Velu, G. et al. A 360° BST phase shifter with moderate bias voltage at 30 GHz. IEEE Trans. Microwave Theory Tech. 55, 438–444 (2007).Koh, K. J. & Rebeiz, G. M. A 6-18 GHz active phase shifter. In Proceedings IEEE Microwave Symposium Digest 792–795 (2010).Capmany, J., Pastor, D. & Ortega, B. New and flexible fiber-optic delay-line filters using chirped Bragg gratings and laser arrays. IEEE Trans. Microwave Theory Tech. 47, 1321–1326 (1999).Minasian, R. A. Photonic signal processing of microwave signals. IEEE Trans. Microwave Theory Tech. 54, 832–846 (2006).Dai, Y. & Yao, J. P. Nonuniformly-spaced photonic microwave delay-line filter. Opt. Express 16, 4713–4718 (2008).Hamidi, E., Leaird, D. E. & Weiner, A. M. Tunable programmable microwave photonic filters based on an optical frequency comb. IEEE Trans. Microwave Theory Tech. 58, 3269–3278 (2010).Chan, E. H. W. & Minasian, R. A. Coherence-free high-resolution RF/microwave photonic bandpass filter with high skirt selectivity and high stopband attenuation. J. Lightwave Technol. 28, 1646–1651 (2010).Norberg, E. J. et al. Programmable photonic microwave filters monolithically integrated in InPinGaAsP. J. Lightwave. Technol. 29, 1611–1619 (2011).Chen, H. W. et al. Integrated microwave photonic filter on a hybrid silicon platform. IEEE Trans. Microwave Theory Tech. 58, 3213–3219 (2010).Dong, P. et al. GHz-bandwidth optical filters based on high-order silicon ring resonators. Opt. Express 18, 23784–23789 (2010).Lloret, J. et al. Tunable complex-valued multi-tap microwave photonic filter based on single silicon-on-insulator microring resonator. Opt. Express 19, 12402–12407 (2011).Notomi, M. et al. Extremely large group-velocity dispersion of line-defect waveguides in photonic crystal slabs. Phys. Rev. Lett. 87, 253902 (2001).Knight, J. C. Photonic crystal fibres. Nature 424, 847–851 (2003).Supradeepa, V. R. et al. Comb-based radiofrequency photonic filters with rapid tunability and high selectivity. Nat. Photon. 6, 186–194 (2012).Capmany, J., Ortega, B., Pastor, D. & Sales, S. Discrete-time optical processing of microwave signals. J. Lightwave Technol. 23, 702–723 (2005).Hunter, D. B. & Minasian, R. A Tunable microwave fiber-optic bandpass filters. IEEE Photon. Tech. Lett. 11, 874–876 (1999).Baba, T. Slow light in photonic crystals. Nat. Photon. 2, 465–473 (2008).Kuramochi, E. et al. Disorder-induced scattering loss of line-defect waveguides in photonic crystal slabs. Phys. Rev B 72, 161318 (2005).Ishikura, N., Baba, T., Kuramochi, E. & Notomi, M. Large tunable fractional delay of slow light pulse and its application to fast optical correlator. Opt. Express 19, 24102–24108 (2011).O'Faolain, L. et al. Loss engineered slow light waveguides. Opt. Express 18, 27627–27638 (2010).Baron, A., Mazoyer, S., Smigaj, W. & Lalanne, P. Attenuation Coefficient of Single-Mode Periodic Waveguides. Phys. Rev. Lett. 107, 153901 (2011).Patterson, M. et al. Disorder-Induced Coherent Scattering in Slow-Light Photonic Crystal Waveguides. Phys. Rev. Lett. 102, 253903 (2009).Mazoyer, S., Hugonin, J. P. & Lalanne, P. Disorder-Induced Multiple Scattering in Photonic-Crystal Waveguides. Phys. Rev. Lett. 103, 063903 (2009).Combrié, S. et al. Time-delay measurement in singlemode, low-loss photonic crystal waveguides. Electron. Lett. 42, 86–87 (2006).Liang, J. et al. Wideband ultraflat slow light with large group index in a W1 photonic crystal waveguide. J. App. Phys. 110, 063103 (2011).Roy, S. Modeling the dispersion of the nonlinearity in slow mode photonic crystal waveguides. IEEE Photonics. Journal 4, 224–233 (2012).Colman, P., Combrié, S. & De Rossi, A. Control of dispersion in photonic crystal waveguides using group symmetry theory. Opt. Express 20, 13108–13114 (2012).Vy Tran, Q., Combrié, S., Colman, P. & De Rossi, A. Photonic crystal membrane waveguides with low insertion losses. Appl. Phys. Lett. 95, 061105 (2009).Bolea, M., Mora, J., Ortega, B. & Capmany, J. Highly chirped single-bandpass microwave photonic filter with reconfiguration capabilities. Opt. Express 19, 4566–4576 (2011).Binetti, P. et al. Indium phosphide integrated circuits for coherent optical links. IEEE J. Quantum Electron. 48, 279–291 (2012).Thomson, D. J. et al. High contrast 40Gbit/s optical modulation in silicon. Opt. Express 19, 11507–11516 (2011).Asghari, M. & Krishnamoorthy, A. V. Energy efficient communication. Nat. Photon. 5, 268–270 (2011).Vivien, L. et al. Zero-bias 40Gbit/s germanium waveguide photodetector on silicon. Opt. Express 20, 1096–1101 (2012).Feng, N. N. et al. 30GHz Ge electro-absorption modulator integrated with 3 μm silicon-on-insulator waveguide. Opt. Express 19, 7062–7067 (2011).Trinh, P. D., Yegnanarayanan, S., Coppinger, F. & Jalali, B. Compact multimode interference couplers in Silicon-on-insulator technology. Conference on Lasers and Electro-Optics CLEO '97CThV4, 441 (Baltimore, USA, 1997).Loayssa, A., Capmany, J., Sagues, M. & Mora, J. Demonstration of incoherent microwave photonic filters with all-optical complex coefficients. IEEE Photon. Tech. Lett. 18, 1744–1746 (2006).Zhang, W. & Minasian, R. A. Widely tunable single-passband microwave photonic filter based on stimulated Brillouin scattering. IEEE Photon. Tech. Lett. 23, 1775–1777 (2011).Xue, W., Sales, S., Mork, J. & Capmany, J. Widely tunable microwave photonic notch filter based on slow and fast light effects. IEEE Photon. Tech. Lett. 21, 167–169 (2009).Norberg, E. J. et al. A monolithic programmable optical filter for RF signal processing. in Proceedings Microwave Photonics Conf. (Montreal, Canada, 2010).Vlasov, Y. A., O'Boyle, M., Hamann, H. F. & McNab, S. J. Active control of slow light on a chip with photonic crystal waveguides. Nature 438, 65–69 (2005).Eckhouse, V. et al. Highly efficient four wave mixing in GaInP photonic crystal waveguides. Opt. Lett. 35, 1440–1442 (2010).Sagues, M. et al. Multi-tap complex-coefficient incoherent microwave photonic filters based on optical single-sideband modulation and narrow band optical filtering. Opt. Express 16, 295–303 (2008).Huang, T. X. H., Yi, X. & Minasian, R. A. Single passband microwave photonic filter using continuous-time impulse response. Opt. Express 19, 6231–6242 (2011).Burla, M. et al. On-chip CMOS compatible reconfigurable optical delay line with separate carrier tuning for microwave photonic signal processing. Opt. Express 19, 21475–21484 (2011)

Intense x-ray machine for penetrating radiography

Penetrating radiography has been used for many years in the nuclear weapons research programs. In frequently penetrating radiography has been used in conventional weapons research programs. For example the Los Alamos PHERMEX machine was used to view uranium rods penetrating steel for the GAU-8 program, and the Ector machine was used to see low-density regions in forming metal jets. The armor/anti-armor program at Los Alamos has created a need for an intense flash x-ray machine that can be dedicated to conventional weapons research. The Balanced Technology Initiative, through DARPA, has funded the design and construction of such a machine at Los Alamos. It will be an 8- to 10-MeV diode machine capable of delivering a dose of 500 R at 1 m with a spot size of less than 5 mm. The machine used an 87.5-stage low-inductance Marx generator that charges up a 7.4-/Omega/, 32-ns water line. The water line is discharged through a self-breakdown oil switch into a 12.4-/Omega/ water line that rings up the voltage into the high-impendance x-ray diode. A long (233-cm) vacuum drift tube is used to separate the large-diameter oil-insulated diode region from the x-ray source area that may be exposed to high overpressures by the explosive experiments. The electron beam is self-focused at the target area using a low-pressure background gas. 15 refs., 11 figs