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Non-tuberculous mycobacterial (NTM) infection of the musculoskeletal system is rare but poses a grave threat to public health. These infections yield non-specific symptoms that remain undetected until the development of the later stages of the disease. In this study, we performed a retrospective review of 25 cases of musculoskeletal NTM infection at two tertiary medical centres over a 5-year period to determine the clinical features and improve the current clinical diagnosis and treatment. The most common mycobacterial species detected were Mycobacterium fortuitum in eleven patients, Mycobacterium abscessus in eight patients, Mycobacterium houstonense in three patients, Mycobacterium avium in two patients, and Mycobacterium smegmatis in one patient. The sites of infection included the limbs and joints, most commonly the knee (ten patients) and foot (six patients). The median duration from the onset of symptoms to diagnosis was 2.5 months (0.8–13.5 months). Deep sinus tracts extending to the surgical site were observed in 60% of the patients (15/25), and granulomatous inflammation and granulomatous inflammation with necrosis occurred in 60% of the patients (15/25). All patients underwent surgical treatment for infection control, and all patients, except one, received antimycobacterial therapy based on drug sensitivity assays. The median duration of the antimicrobial chemotherapy was 5 months (range: 3–20 months). At the final follow-up, 24 patients presented with absence of recurrence and one patient succumbed owing to heart failure after debridement. Our findings highlight the importance of vigilance and improvements in the diagnostic methods for musculoskeletal NTM infection. Aggressive surgical treatment and antimycobacterial drug treatment can help achieve satisfactory results. [ABSTRACT FROM AUTHOR]

High power impulse magnetron sputtering (HiPIMS) discharge promises high ionization fraction and energetic ions in comparison with dc magnetron sputtering discharge. But acknowledge on the characteristics of HiPIMS plasma in the near-substrate region (substrate vicinity), which is of great importance for film deposition, is still limited. Here, optical emission spectroscopy (OES) combined with the collisional-radiative modelling are developed and used to determine the electron temperature and the number density of neutral sputtered atom for the chromium HiPIMS plasma in substrate vicinity. The OES analysis demonstrated the HiPIMS discharge of Cr sputtering process in low density mode was dominated by the electron impact ionization of argon atoms and excitation of chromium atoms. As the HiPIMS plasma in the substrate vicinity is far from the local thermal equilibrium state, the relative intensities of transition lines to ArI 4p states was used to calculate the electron temperature. Subsequently, the neutral chromium atoms density about 1017 m−3 was reported in the near-substrate region. Our findings have important implications for species generation in low density HiPIMS discharge, with applications in synthesis of dense chromium coatings. [ABSTRACT FROM AUTHOR]

Discharge behaviors of high-power impulse magnetron sputtering with different targets have been investigated. Distinct current–voltage curves and target current waveforms are observed. Breakdown voltage and the maximum target current show a periodic drop with the increase of atomic number in subgroups and periods. The target current density is found to be mainly affected by the secondary electron emission yield. Thus, its magnitude is unable to directly evaluate the ionization degree of sputtered atoms in high-power impulse magnetron sputtering (HiPIMS) process. In this paper, the interactive influence of secondary electron emission, sputter yield, and ionization energy on the ionization degree of sputtered atoms is discussed based on the analysis of the voltage and current characteristics. As a result, targets can be categorized into three sorts according to the ionization degree: 1) low ionization degree targets, such as Ag and C less than 10%; 2) intermediate ionization degree targets like Cr and Cu with 55% and 35%; 3) Ti, Zr, and Mo targets with the second ionization processes. These results provide institutive operation ranges for the state-of-the-art HiPIMS applications. [ABSTRACT FROM AUTHOR]

Regardless of used metal contact combinations, bulk-limited electrical behaviors were observed in metal/hydrogenated diamond-like carbon (DLC)/metal (MSM) devices through the study of I-V curves and temperature dependence of conductivity. For MSM devices with DLC deposited at a substrate bias of -50 V, the I-V curves exhibited ohmic electrical behaviors in the range of 0–1 V and followed the Poole-Frenkel mechanism in the range of 1–5 V. Moreover, the carrier transport was dominated by the thermally activated process with an activation energy of 0.1576 eV in the temperature range of 160–400 K. The bulk-limited behaviors of MSM devices could be attributed to the relatively high bulk resistance of the DLC layer. This result offers the fundamental insight into DLC based electrical devices and brings forward the concept to fabricate functional carbon based materials. [ABSTRACT FROM AUTHOR]

The electrical characteristics and spectroscopic properties have been comprehensively investigated in a DC superimposed high power impulse magnetron sputtering (DC-HiPIMS) deposition system in this paper. The influence of superimposed DC current on the variation of target and substrate current waveforms, active species and electron temperatures with pulse voltages are focused. The peak target currents in DC-HiPIMS are lower than in HiPIMS. The time scales of the two main discharge processes like ionization and gas rarefaction in DC-HiPIMS are analyzed. When the pulse voltage is higher than 600 V, the gas rarefaction effect becomes apparent. Overall, the ionization process is found to be dominant in the initial ∼100 μs during each pulse. The active species of Ar and Cr in DC-HiPIMS are higher than in HiPIMS unless that the pulse voltage reaches 900 V. However, the ionization degree in HiPIMS exceeds that in DC-HiPIMS at around 600 V. The electron temperature calculated by modified Boltzmann plot method based on corona model has a precipitous increase from 0.87 to 25.0 eV in HiPIMS, but varies mildly after the introduction of the superimposed DC current. Additionally, the current from plasma flowing to the substrate is improved when a DC current is superimposed with HiPIMS. [ABSTRACT FROM AUTHOR]