Comparison of outcomes of different modalities of renal replacement therapy in patients of acute kidney injury: a single centre prospective observational study.

BACKGROUND: Acute Kidney Injury (AKI) is one of the most important causes of in-hospital mortality. The global burden of AKI continues to rise without a marked reduction in mortality. As such, the use of renal replacement therapy (RRT) forms an integral part of AKI management, especially in critically ill patients. There has been much debate over the preferred modality of RRT between continuous, intermittent and intermediate modes. While there is abundant data from Europe and North America, data from tropical countries especially the Indian subcontinent is sparse. Our study aims to provide an Indian perspective on the dialytic management of tropical AKI in a tertiary care hospital setup. METHODS: 90 patients of AKI, 30 each undergoing Continuous Renal Replacement Therapy (CRRT), Intermittent Hemodialysis (IHD) and SLED (Sustained Low-Efficiency Dialysis) were included in this prospective cohort study. At the end of 28 days of hospital stay, discharge or death, outcome measures were ascertained which included mortality, duration of hospital stay, recovery of renal function and requirement of RRT after discharge. In addition median of the net change of renal parameters was also computed across the three groups. Lastly, Kaplan Meier analysis was performed to assess the probability of survival with the use of each modality of RRT. RESULTS: There was no significant difference in the primary outcome of mortality between the three cohorts (p=0.27). However, CRRT was associated with greater renal recovery (p= 0.015) than IHD or SLED. On the other hand, SLED and IHD were associated with a greater net reduction in blood urea (p=0.004) and serum creatinine (p=0.053). CONCLUSION: CRRT, IHD and SLED are all complementary to each other and are viable options in the treatment of AKI patients.

Thermal effects associated with the Raman spectroscopy of WO3 gas-sensor materials.

Metal oxides are suitable for detecting, through conductive measurements, a variety of reducing and oxidizing gases in environmental and sensing applications. Metal-oxide gas sensors can be developed with the goal of sensing gases under specific conditions and, as a whole, are heavily dependent on the manufacturing process. Tungsten oxide (WO3) is a promising metal-oxide material for gas-sensing applications. The purpose of this paper is to determine the existence of a correlation between thermal effects and the changes in the Raman spectra for multiple WO3 structures. We have obtained results utilizing Raman spectroscopy for three different structures of WO3 (monoclinic WO3 on Si substrate, nanopowder, and nanowires) that have been subjected to temperatures in the range of 30-160 °C. The major vibrational modes of the WO3:Si and the nanopowder samples, located at ~807, ~716, and ~271 cm(-1), correspond to the stretching of O-W-O bonds, the stretching of W-O, and the bending of O-W-O, respectively; these are consistent with a monoclinic WO3 structure. However in the nanowires sample only asymmetric stretching of the W-O bonds occurs, resulting in a 750 cm(-1) band, and the bending of the O-W-O mode (271 cm(-1)) is a stretching mode (239 cm(-1)) instead, suggesting the nanowires are not strictly monoclinic. The most notable effect of increasing the temperature of the samples is the appearance of the bending mode of W-OH bonds in the approximate range of 1550-1150 cm(-1), which is related to O-H bonding caused by humidity effects. In addition, features such as those at 750 cm(-1) for nanowires and at 492 and 670 cm(-1) for WO3:Si disappear as the temperature increases. A deeper understanding of the effect that temperature has on the Raman spectral characteristics of a metal oxide such as WO3 has helped to extend our knowledge regarding the behavior of metal oxide-gas interactions for sensing applications. This, in turn, will help to develop theoretical models for the identification of specific metal oxide-gas relationships.

Femtosecond laser-induced breakdown spectroscopy of surface nitrate chemicals.

Ultrashort laser-induced breakdown spectroscopy was used to detect the emission radiation from the breakdown of surface contaminants by a femtosecond laser pulse. This study focused on the detection of visible to near-infrared radiation signatures from molecular fragments of the nitro (NO(x)) group present in the breakdown plasma, where target chemicals of potassium nitrate (KNO(3)) and sodium nitrate (NaNO(3)) were used. Spectral signatures at a wavelength region around 410 nm were observed for both KNO(3) and NaNO(3), and were identified as the fluorescence transitions of the NO(x)-molecular structures. The signatures obtained were systematically analyzed and studied as functions of laser parameters. It is shown that for laser parameters used in this study, laser pulse durations ≥1 ps were not as effective as shorter pulses in generating these signatures. A visible wavelength NO(x) signature and the extended high-intensity propagation of a femtosecond laser could be advantageous to detecting nitro-group energetic materials at standoff distances.