Fatal Clostridium septicum myonecrosis from gastric perforation: A case report.

Clostridial myonecrosis is a medical and surgical emergency which requires early and aggressive intervention to reduce mortality. We report a rare case of Clostridium septicum myonecrosis that disseminated hematogenously from a gastric perforation. The patient was afebrile and hemodynamically stable upon admission. He rapidly developed spontaneous clostridial myonecrosis and succumbed to septic shock 36 hours after presentation. In our extensive literature review this is the only case with blood cultures confirming Clostridium septicum bacteremia with a surgically confirmed gastric perforation source in the setting of spontaneous clostridial myonecrosis.

Ammonothermal Crystal Growth of Functional Nitrides for Semiconductor Devices: Status and Potential.

The state-of-the-art ammonothermal method for the growth of nitrides is reviewed here, with an emphasis on binary and ternary nitrides beyond GaN. A wide range of relevant aspects are covered, from fundamental autoclave technology, to reactivity and solubility of elements, to synthesized crystalline nitride materials and their properties. Initially, the potential of emerging and novel nitrides is discussed, motivating their synthesis in single crystal form. This is followed by a summary of our current understanding of the reactivity/solubility of species and the state-of-the-art single crystal synthesis for GaN, AlN, AlGaN, BN, InN, and, more generally, ternary and higher order nitrides. Investigation of the synthesized materials is presented, with a focus on point defects (impurities, native defects including hydrogenated vacancies) based on GaN and potential pathways for their mitigation or circumvention for achieving a wide range of controllable functional and structural material properties. Lastly, recent developments in autoclave technology are reviewed, based on GaN, with a focus on advances in development of in situ technologies, including in situ temperature measurements, optical absorption via UV/Vis spectroscopy, imaging of the solution and crystals via optical (visible, X-ray), along with use of X-ray computed tomography and diffraction. While time intensive to develop, these technologies are now capable of offering unprecedented insight into the autoclave and, hence, facilitating the rapid exploration of novel nitride synthesis using the ammonothermal method.

Prospective derivation and validation of a NECROtizing Soft tissue InfectionS (NECROSIS) score: An EAST multicenter trial.

BACKGROUND: Although several risk indices have been developed to aid in the diagnosis of NSTIs, these instruments suffer from varying levels of reproducibility and failure to incorporate key clinical variables in model development. The objective of this study was to derive and validate a clinical risk index score - NECROSIS - for identifying NSTIs in emergency general surgery (EGS) patients being evaluated for severe skin and soft tissue infections. METHODS: We performed a prospective study across 16 sites in the US of adult EGS patients with suspected NSTIs over a 30-month period. Variables analyzed included demographics, admission vitals and labs, physical exam, radiographic, and operative findings. The main outcome measure was the presence of NSTI diagnosed clinically at the time of surgery. Multivariate analysis was performed to identify independent predictors for the presence of NSTI using the Hosmer-Lemeshow test and the Akaike information criteria. RESULTS: Of 362 patients, 297 (82%) were diagnosed with a NSTI. Overall mortality was 12.3%. Multivariate analysis identified 3 independent predictors for NSTI: systolic blood pressure ≤ 120 mmHg, violaceous skin, and WBC ≥15 (x103/uL). Multivariate modelling demonstrated Hosmer-Lemeshow goodness of fit (p = 0.9) with a c-statistic for the prediction curve of 0.75. Test characteristics of the NECROSIS score were similar between the derivation and validation cohorts. CONCLUSION: NECROSIS is a simple and potentially useful clinical index score for identifying at-risk EGS patients with NSTIs. Future validation studies are warranted. LEVEL OF EVIDENCE: Diagnostic Tests or Criteria, Level III.

Ab initio identification of the nitrogen diffusion mechanism in silicon.

In this Letter, we present ab initio results identifying a new diffusion path for the nitrogen pair complex in silicon, resulting in an effective diffusivity of 67exp((-2.38 eV/kT) cm2/s. This nudged elastic band result is compared with other nitrogen diffusion paths and mechanisms, and is determined to have unmatched agreement with experimental results. It is also shown that careful consideration of total energy corrections and use of a fully temperature-dependent diffusion prefactor have modest but important effects on the calculation of diffusivity for paired and for interstitial nitrogen.