Hydrogen sulfide is an exceptionally stable structure I (sI) gas hydrate forming guest molecule that is becoming increasingly prevalent in oil and gas production. However, phase equilibria data on pure hydrogen sulfide hydrate reported in the literature are relatively limited and inconsistent compared to other common hydrate formers such as methane or carbon dioxide. In this study, 61 hydrate phase equilibria measurements for sI hydrates containing hydrogen sulfide are reported in the temperature range from T = 273.68 K to 301.53 K and pressure range from p = 0.108 MPa to 1.960 MPa. Experimental data were measured using the isochoric pressure search (IPS) method which has been well established, as well as a modified IPS method, termed the phase boundary dissociation (PBD) method, which gives more efficient measurements of pure hydrate phase equilibria data. For example, it was shown in this work that using the new PBD method reduced the experimental run time to approximately 4.8 h per data point, compared to 40 h to 45 h per data point using the IPS method. The measured data for hydrogen sulfide hydrates were compared with predictions and experimental data reported in the literature, showing agreement between measurements and predictions within an average of 0.08 K for HydraFLASH 2.2 to 1.131 K for PVTSim 21 on average and literature within 0.21 K for Selleck et. al 10 to 1.42 K for Carroll and Mather 12 on average.

Phase equilibria data on mixed hydrogen sulfide hydrates reported in the literature are very limited, especially for sII hydrate forming mixtures with H2S. In this study, six binary CH4 + H2S hydrate phase equilibria measurement results are reported in the temperature range from T = (283.31 to 293.22) K and pressure range from p = (2.00 to 6.8) MPa. Ten ternary CH4 + C3H8 + H2S sII hydrate phase equilibria measurement results are reported in the temperature range from T = (286.22 to 304.80) K and pressure range from p = (1.36 to 5.48) MPa. Experimental data were measured using the isochoric pressure search (IPS) method, which has been well established as a method for obtaining accurate hydrate phase equilibria data. Experimental data were compared to several hydrate phase equilibria prediction programs to assess their accuracy. For most models, predictions of the ternary sII hydrate system resulted in average absolute deviations in temperature of greater than 1 K.

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Background The treatment of spinal muscular atrophy (SMA) with nusinersen requires intrathecal medication administration, which can be challenging in individuals with complicated spines. This retrospective case series reviews the nusinersen treatment experience at one academic medical center with children and adults with SMA and complicated spines. Methods Twenty medical records of individuals receiving nusinersen were reviewed and administration methods summarized and assessed. Results Ten children and 10 adults were treated, and 55% had complicated spines. In total, 163 treatments were given, 91 in those with complicated spines. In the complicated spines, 74% of treatments were done by means of fluoroscopic lumbar puncture, 22% by means of intrathecal Ommaya reservoir, 3% by means of palpation, and < 1% by means of computed tomography‐guided transforaminal approach. Conclusions A large majority of individuals with complicated spines can receive intrathecal nusinersen using fluoroscopic guidance in the lumbar region. Other delivery methods are available but less frequently used.

The dissociation process of spherical sII mixed methane-propane hydrate particles in liquid hydrocarbon was investigated via microsecond-long Molecular Dynamics simulations. A strong dependence of the melting temperature on the particle...