Diamonds in the Rough: Direct Surface Enhanced Infrared Spectroscopic Evidence of Nitrogen Reduction on Boron-Doped Diamond Supported Metal Catalysts.

In situ investigations of electrocatalytic processes of increasing societal interest such as the nitrogen reduction reaction (NRR) require aggressive experimental conditions that are not readily compatible with surface sensitive techniques such as attenuated total reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS). A method for performing ATR-SEIRAS studies at very negative potentials where conventional IR-active films delaminate and fail is reported. The method relies on a thin film of very robust boron-doped diamond deposited on a micromachined Si wafer, which provides extended mid-IR transparency at long wavelengths. SEIRAS activity is achieved by electrodepositing gold nanoparticles onto the conductive BDD layer. The Au@BDD layers are shown to sustain prolonged periods of electrolysis at negative potentials, with no degradation of the modifying layer. The efficacy of these substrates for electrocatalysis is demonstrated by studying the reduction of N2 at -1.5 V vs Ag/AgCl in an aqueous-based electrolyte. Under these conditions, direct spectroscopic evidence of both NH3 and hydrazine formed from the nitrogen reduction reaction (NRR) is provided.

Nano-Plasticity of an Electrified Ionic Liquid/Electrode Interface: Uncovering Hard-Soft Structuring via Controlled Metal Fill Factor.

Ionic liquids (ILs) nanostructuring at electrified interfaces is of both fundamental and practical interest as these materials are increasingly gaining prominence in energy storage and conversion processes. However, much remains unresolved about IL potential-controlled (re)organization under highly polarized interfaces, mostly due to the difficulty of selectively probing both the distal and proximal surface layers of adsorbed ions. In this work, the structural dynamics of the innermost layer (<10 nm from the surface) were independently interrogated from that of the ionic layers in the sub-surface region (>100 nm from the surface), using an infrared (IR) spectroscopy approach. By tuning the metal fill factor of gold films deposited on conductive metal oxide-modified IR internal reflection elements, the charge-driven (re)structuring of the inner and distal layers of 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate is unveiled. Within a relatively wide potential region (∼±1 V) bounding the potential of zero charges, the ionic liquid is shown to undergo a reversible (i.e., soft) reorganization whereby the innermost layer of anions (cations) is exchanged by a layer of cations (anions). Kinetically unhindered changes in the number density of constituent cations and anions largely follow electrostatic expectations in the subsurface region, whereas the innermost layer exhibits a pronounced hysteresis and very slow relaxation. Under larger negative potential bias, IL restructuring is characterized by a highly irreversible (i.e., hard) and intense interfacial densification of the BMPy+ cations, consistent with the formation of nanoscale segregated liquids. The outcomes of this work reveal a plastic IL nanostructuring under a strong electric field.

The effect of post-discharge oral nutritional supplements on outcomes after gastrointestinal surgery: A systematic review and meta-analysis.

BACKGROUND: Malnutrition is a risk-factor for adverse postoperative outcomes. This systematic review and meta-analysis evaluated the impact of post-discharge oral nutritional supplements (ONS) on outcomes in patients undergoing gastrointestinal surgery. METHODS: The Medline and Embase databases were searched for randomised clinical trials in patients undergoing gastrointestinal surgery who had received ONS for at least two weeks after discharge from hospital. The primary endpoint was weight change. Secondary endpoints included quality of life, total lymphocyte count, total serum protein and serum albumin. Analysis was performed using RevMan5.4 software. RESULTS: Fourteen studies with 2480 participants (1249 ONS/1231 controls) were included. Pooling of results revealed that a reduction in postoperative weight loss in patients taking ONS, when compared with control: overall weighted mean difference (WMD) -1.69 kg, 95% CI -2.98 to -0.41, P = 0.01. Serum albumin concentration was increased in the ONS group: WMD = 1.06 g/L, 95% CI 0.04 to 2.07, P = 0.04. Haemoglobin was also increased: WMD = 2.91 g/L, 95% CI 0.58 to 5.25, P = 0.01. Total serum protein, total lymphocyte count, total cholesterol and quality of life did not differ between the groups. Patient compliance was relatively poor across the studies and there was variability in the composition of ONS, volume consumed and surgical procedures performed. CONCLUSIONS: There was a reduction in postoperative weight loss and an improvement in some biochemical parameters in patients receiving ONS after gastrointestinal surgery. Future RCTs with more consistent methodologies are needed to investigate the efficacy of ONS after discharge from hospital following gastrointestinal surgery.

Rapid and accurate etizolam detection using surface-enhanced Raman spectroscopy for community drug checking.

BACKGROUND: In British Columbia, Canada, illicit opioids have been increasingly combined with etizolam, a benzodiazepine analog, that continues to challenge popular portable drug checking technologies as it is often present in low concentrations as a result of its high potency. An unknown combination of opioids and benzodiazepines may have dangerous consequences due to unpredictable dosing, increased respiratory depression, and complicated overdose response measures. METHODS: Surface-enhanced Raman spectroscopy (SERS) using a portable Raman spectrometer is used to establish a univariate model for the detection of etizolam in opioid drug mixtures (n=100) obtained from the Vancouver Island Drug Checking Project, where the presence of etizolam has been determined using paper-spray mass spectrometry. Benzodiazepine immunoassay test strips are also performed on all samples for comparison. RESULTS: SERS is shown to detect etizolam with high sensitivity (96%) and specificity (86%). In contrast, benzodiazepine test strips demonstrate a low sensitivity (8%) for the detection of etizolam of the same samples (n=100), with only small improvements when studied over a larger subset of samples (n=506, sensitivity = 29%). CONCLUSION: We have demonstrated the potential of SERS for trace detection of etizolam within complex sample matrices. Since SERS is one of the few portable technologies capable of trace detection, further studies on its ability for quantification and discrimination of trace adulterants in street samples is of significant interest for point-of-care applications.