Field observations of C2 and C3 organosulfates and insights into their formation mechanisms at a suburban site in Hong Kong.

Organosulfates (OSs) are formed from volatile organic compounds (VOCs) and their oxidation products in the presence of sulfate particles. While OSs represent an important component in secondary organic aerosol, the knowledge of their formation driving force, mechanisms, and environmental impact remain inadequately understood. In this study, we report ambient observations of C2-3 oxygenated VOCs derived OSs (C2-3 OSs) at a suburban location of Hong Kong during autumn 2016. The C2-3 OSs, including glycolaldehyde sulfate (GS), hydroxyacetone sulfate (HAS), glycolic acid sulfate (GAS), and lactic acid sulfate (LAS), were quantified/semi-quantified using offline liquid chromatography-mass spectrometry analysis of aerosol filter samples. The average sum concentration of C2-3 OSs was 36 ng/m3. Correlation analysis revealed that sulfate, surface area, and liquid water content were important factors influencing C2-3 OS formation. Online measurement with an iodide High-Resolution Time-of-Flight Chemical-Ionization Mass Spectrometer (HR-ToF-CIMS) coupled with the Filter Inlet for Gases and AEROsols (FIGAERO) was also conducted to monitor C2-3 OSs, and their potential oxygenated VOC precursors in both gas- and particle-phase, and aerosol acidity tracer simultaneously. Our measurements support that glycolaldehyde/glyoxal, hydroxyacetone, glycolic acid/glyoxal, and lactic acid/methylglyoxal are likely precursors for GS, HAS, GAS, and LAS, respectively. Additionally, we found strong correlation between C2-3 OSs and H3S2O8-, a marker for aerosol acidity, providing field observational evidence for acid-catalyzed formation of small OSs. Based on both online and offline measurements, acid-catalyzed formation mechanisms in particle/aqueous phase are proposed. Specifically, the unique structure of adjacent carbonyl and hydroxyl groups in the C2-3 oxygenated VOC precursors can facilitate the formation of (1) a five-member ring intermediate via intramolecular hydrogen bond to react with sulfur trioxide through heterogenous reaction or (2) cyclic sulfate intermediate via particle-phase reaction with sulfuric acid to generate C2-3 OSs. These proposed mechanisms provide an alternative pathway for the liquid-phase production of C2-3 OSs.

Lichen planus pemphigoides: A unique form of bullous and lichenoid eruptions secondary to nivolumab.

The widespread use of PD-1 inhibitors to treat various solid tumors has brought certain challenges for the clinician, including immune-related adverse events (irAEs). Cutaneous toxicities are among the most observed irAEs. Bullous and lichenoid dermatoses following PD-1 inhibitor therapy have been described. Here we report a novel case of lichen planus pemphigoides, featuring characteristics of both bullous pemphigoid and lichen planus, in a patient treated with nivolumab for renal cell carcinoma. We subsequently review all three cutaneous conditions which may arise in the context of PD-1 inhibitor therapy.

Scheduled analgesic regimen improves rehabilitation after hip fracture surgery.

BACKGROUND: Postoperative pain often is the limiting factor in the rehabilitation of patients after hip fracture surgery. QUESTIONS/PURPOSES: We compared an approach using scheduled analgesic dosing with as-needed analgesic dosing in patients after hip fracture surgery, to compare these approaches in terms of (1) resting and dynamic pain intensity, (2) postoperative patient mobility, and (3) functional end points. METHODS: We conducted a prospective cohort study of 400 patients who underwent surgical treatment of hip fractures at our hospital. The groups were formed sequentially, such that the first 200 patients formed the intervention group (treated with scheduled analgesic intake for the first 3 weeks after surgery), and the next 200 patients were the control group (treated using a protocol of analgesic administration on request). Resting and dynamic pain intensity, mobility, and functional performance were compared between the two analgesic protocols. RESULTS: As expected, analgesic consumption was lower in the control group (tramadol doses, 27 versus 63; paracetamol doses, 29 versus 63). Despite the large difference in the amounts of analgesics consumed, resting and dynamic pain intensity showed improvement in each group and there was no difference between groups in terms of postoperative pain. However, there was a positive correlation between functional outcomes and analgesic consumption in the control group. The intervention group achieved higher functional performance on discharge (elderly mobility scale, 11 versus 8; functional independence measure, 88 versus 79). On discharge, fewer patients in the intervention group were wheelchair ambulators (3 versus 32), meaning more patients in the intervention group were able to walk. CONCLUSIONS: The study showed that a scheduled analgesic intake can improve the functional outcomes of patients with geriatric hip fractures after surgery. LEVEL OF EVIDENCE: Level II, therapeutic study. See the guidelines for authors for a complete description of levels of evidence.

Monitoring the use of halo fixation device through an assessment form.

PURPOSE: To compare the use of the halo fixation device in our hospital before and after implementation of a new compliance protocol. METHODS: From 2003 to 2008, 17 (47%) of 36 patients had dislodgement of their halo fixation device. All rings and vests and some of the pins were reused. Documentation of poundage assessment and change of skull pins before dislodgement was lacking. There was no protocol for assessing superstructure throughout the course of the application. To improve the standard of care, knowledge about the application of the halo fixation device in orthopaedic and orthotic departments was reinforced and compliance documented. From September 2008 to April 2010, 15 patients used the halo fixation device for cervical immobilisation. Patients were reminded to minimise shoulder shrugging and report any discomfort. Poundage checking was strictly observed during and after application. The integrity of the device was regularly checked by orthotists. The conditions of the skull pins, halo ring, and vest were also documented after removal. RESULTS: Two (13%) of the 15 patients had ring dislodgement. One occurred a day after application owing to malposition of a posterior skull pin, and the other was related to a fall in a toilet at week 4. Both involved reused skull pins. 45% of the skull pins were new, whereas 44% were found defective after removal of rings. Compliance with the new assessment form was satisfactory. CONCLUSION: Clinical audit improved outcome achieved with the halo fixation device. Reuse of titanium skull pins should be avoided. Re-torquing of the pin should be avoided when the tip is blunted or hooked. The new assessment form enabled compliance with the principle of application by orthotists and patients.