Prevalence of SIRS with primary epiploic appendagitis.

PURPOSE: Primary epiploic appendagitis (PEA) is not an uncommon cause of abdominal pain. The systemic inflammatory response syndrome (SIRS) criteria have high sensitivity for early detection of inflammation and infection. To date, there is limited data about the association between SIRS and PEA. The aims of this retrospective study were to evaluate the prevalence of SIRS response and its clinical relevance in patients diagnosed with PEA within a large tertiary hospital network. METHODS: A retrospective study was performed on all consecutive adult patients who presented to four major emergency departments with CT-confirmed PEA from 01 January 2022 to 27 March 2023. The fulfilment of SIRS criteria, hospital admission rate and treatments provided were analysed for these patients. RESULTS: Seventy-three patients had CT-confirmed PEA. Seventeen patients (23.2%) with PEA were SIRS positive. The hospital admission rate in the SIRS group trended higher than the non-SIRS group (odds ratio of 2.51, 95% CI (0.75, 8.39)). The odds of having an associated radiological comorbidity unrelated to PEA were 18.7 times higher in the SIRS positive group. Fifty-seven (78%) patients were discharged home, and 16 (22%) patients were admitted into hospital. Nearly all patients were treated conservatively (98.6%). CONCLUSION: PEA patients with SIRS response trend towards a higher hospital admission rate and are significantly more likely to have other radiological comorbidities than non-SIRS patients. It is important to look for other pathological conditions in a SIRS positive patient with a CT-diagnosis of PEA.

High-pitched tin-filtered CT pulmonary angiography in radiation dose reduction for pulmonary embolism investigations in young females.

INTRODUCTION: Computed tomography pulmonary angiography (CTPA) is the gold standard test to investigate pulmonary embolism (PE). This technique carries significant radiation risk in young females because of radiosensitive breast and thyroid tissues. A high-pitched CT technique offers significant radiation dose reduction (RDR) and minimises breathing artefact. The addition of CT tube tin-filtration may offer further RDR. The aim of this retrospective study was to assess RDR and image quality (IQ) of high-pitch tin-filtered (HPTF)-CTPA against conventional-CTPA. METHODS: Retrospective review of consecutive adult females age < 50 years undergoing high pitch tin filtration (HPTF) and standard pitch no tin filtration (SPNF) during a 3-year period beginning in November 2017. CTs in both groups were compared for radiation dose, pulmonary arteries contrast density (Hounsfield units (HU)) and movement artefact. Findings of both groups were compared with the Student's T-test and Mann-Whitney U test, where p < 0.05 being considered significant. Diagnostic quality was also recorded. RESULTS: Ten female patients (mean age 33, 6/10 pregnant) in HPTF group and 10 female patients (mean age 36, 1/10 pregnant) in SPNF group were included. The HPTF group achieved 93% RDR (dose length product: 25.15 mGy.cm vs 337.10 mGy.cm, p < 0.01). There was significant contrast density difference between the two groups in the main, left or right pulmonary arteries (322.72 HU, 311.85 HU and 319.41 HU in HPTF group vs 418.60 HU, 405.10 HU and 415.96 HU in SPNF group respectively, p = 0.03, p = 0.03 and p = 0.04). 8/10 HPTF group and 10/10 in the control group were > 250 HU in all three vessels; the remaining 2 HPTF CTPA were > 210HU. All CT scans in both groups were of diagnostic quality and none exhibited movement artefact. CONCLUSION: This study was the first to demonstrate significant RDR with the HPTF technique whilst maintaining IQ in patients undergoing chest CTPA. This technique is particularly beneficial in young females and pregnant females with suspected PE.

Impact of Intraprocedural Sedation on Adrenal Vein Sampling without Corticotropin Stimulation.

See also the editorial by Georgiades in this issue.

Current trends in image-guided chest interventions.

Interventional radiology (IR) is a rapidly expanding medical subspecialty and refers to a range of image-guided procedural techniques. The image guidance allows real-time visualization and precision placement of a needle, catheter, wire and device to deep body structures through small incisions. Advantages include reduced risks, faster recovery and shorter hospital stays, lower costs and less patient discomfort. The range of chest interventional procedures keeps on expanding due to improved imaging facilities, better percutaneous assess devices and advancing ablation and embolization techniques. These advances permit procedures to be undertaken safely, simultaneously and effectively, hence escalating the role of IR in the treatment of chest disorders. This review article aims to cover the latest developments in some image-guided techniques of the chest, including thermal ablation therapy of lung malignancy, targeted therapy of pulmonary embolism, angioplasty and stenting of mediastinal venous/superior vena cava occlusion, pulmonary arteriovenous malformation treatment and bronchial artery embolization for haemoptysis.

Right ventricular end-diastolic volume and outcomes in exacerbations of COPD.

BACKGROUND AND OBJECTIVE: Right ventricular (RV) volumes are crucial outcome determinants in pulmonary diseases. Little is known about the associations of RV volumes during hospitalized acute exacerbations of chronic obstructive pulmonary disease (AECOPD). We aimed to ascertain associations of RV end-diastolic volume indexed to body surface area (RVEDVI) during hospitalized AECOPD and its relationship with mortality in long-term follow-up. METHODS: This is a prospective observational cohort study (December 2013-November 2019, ACTRN12617001562369) using dynamic retrospective ECG-gated computed tomography during hospitalized AECOPD. RVEDVI was defined as normal or high using Framingham Offspring Cohort values. Cox regression determined the prognostic relevance of RVEDVI for death. RESULTS: A total of 148 participants (70 ± 10 years [mean ± SD], 88 [59%] men) were included, of whom 75 (51%) had high RVEDVI. This was associated with more frequent hospital admissions in the 12 months before admission (52/75 [69%] vs. 38/73 [52%], p = 0.04) and higher breathlessness (modified Medical Research Council score, 2.9 ± 1.3 vs. 2.4 ± 1.2, p = 0.007). During follow-up, high RVEDVI was associated with greater mortality (log-rank p = 0.001). In univariable Cox regression, increasing RVEDVI was associated with higher mortality (hazard ratio [HR]: 1.02 per ml/m2 ; 95% CI: 1.01, 1.03; p = 0.001). In multivariable Cox regression, RVEDVI was independently associated with mortality (HR: 1.01 per ml/m2 ; 95% CI: 1.00, 1.03; p = 0.050) at a borderline significance level. Adding RVEDVI to three COPD mortality prediction systems improved model fit (pooled chi-square test [BODE: p = 0.05, ADO: p = 0.04, DOSE: p = 0.02]). CONCLUSION: In patients with hospitalized AECOPD, higher RV end-diastolic volume was associated with worse acute clinical parameters and greater mortality.

Efficacy of the scatter correction algorithm in portable chest radiography.

PURPOSE: Portable chest radiographs (CXRs) continue to be a vital diagnostic tool for emergency and critical care medicine. The scatter correction algorithm (SCA) is a post-processing algorithm aiming to reduce scatter within portable images. This study aimed to assess whether the SCA improved image quality (IQ) in portable CXRs. METHODS: Objective and subjective IQ assessments were undertaken on both phantom and clinical images, respectively. For objective analysis, attenuators were placed on the anterior surface of the patient's thorax to simulate pathologies present within uniform regions of the phantom's lung and heart. Phantom CXRs were acquired with three different tube-current-times (mAs). Phantom images were processed with different SCA strengths. Contrast to noise ratios (CNR) within the attenuator were determined for each algorithm strength and compared to non-SCA images. For subjective analysis, two independent radiologists graded 30 clinical images with and without the SCA activated. The images were graded for IQ in different anatomical structures and overall diagnostic confidence. RESULTS: Objectively, most strengths of the SCA improved the CNR in both regions. However, a detrimental effect was recorded for some algorithm strengths in regions of high contrast. Subjectively, both observers recorded the SCA significantly improved IQ in clinical CXRs in all anatomical regions. Observers indicated the greatest improvement in the lung and hilar regions, and least improvement in the chest wall and bone. All images with and without the SCA were deemed diagnostic. CONCLUSION: This study shows the potential radiation dose neutral IQ improvement when using an SCA in clinical patient CXRs.

Conformal Growth of Ultrathin Hydrophilic Coatings on Hydrophobic Surfaces Using Initiated Chemical Vapor Deposition.

Hydrophilic poly(2-hydroxyethyl methacrylate) (PHEMA) was deposited onto hydrophobic polytetrafluoroethylene (PTFE) surfaces using initiated chemical vapor deposition. By tuning the reactor conditions, the reaction kinetics were varied to achieve a wide range of deposition rates that spanned over 2 orders of magnitude (∼0.1-10 nm/min). Depositions rates at >1 nm/min were successful in overcoming the interfacial energy and wettability barriers between the hydrophobic and hydrophilic polymers and were found to achieve both conformal and ultrathin coatings. PHEMA coatings as thin as ∼10 nm over PTFE were able to transform a hydrophobic surface with a water contact angle of ∼110° to a hydrophilic one with an angle of ∼20°.

Formation and Stability of Thin Condensing Films on Structured Amphiphilic Surfaces.

We present a microamphiphilic surface to promote the formation of a thin, stable liquid film during condensation. The surface consists of a hydrophilic micropillar array with hydrophobic pillar tips and was made using photolithography, deep reactive ion etching, and liftoff. The hydrophobic tips prevent the liquid film from growing thick, thereby keeping the thermal resistance low without the cyclical growth and shedding process of dropwise condensation. The wetting behavior was modeled analytically, and the parameters required for film formation were determined and verified with ESEM experiments. When a surface filled with condensate and lacked a low-pressure zone for the water to leave, a rupture event occurred, and a large Wenzel droplet emerged to flood the surface irreversibly. A number of strategies were found to combat rupture events. Tilting the surface vertically and dipping in a liquid pool gave the condensate a low-pressure region and prevented rupture. Irreversible flooding can also be avoided by ensuring that the emerged droplet was a nonwetting, highly mobile Cassie droplet. Parameters for Cassie-stable amphiphilic surfaces were determined analytically, but the high aspect ratios required prevented the manufacture of these surfaces for this study. Instead a hierarchical design was presented that demonstrated emerged Cassie droplets without challenging the manufacturing limits of the microfabrication procedure. This design avoided Wenzel droplet flooding without the need for a designated low-pressure zone. Additionally, sites for Cassie emergence could be engineered by removing a single pillar from the array at a designated location.

Image Fusion-Augmented Angiography Improves Right Adrenal Vein Cannulation Success Rate in Adrenal Vein Sampling.

Image fusion-augmented angiography to guide cannulation during adrenal vein sampling (AVS) entails fusion between preprocedural CT images on which ring markers indicate adrenal vein ostia and live digital subtraction angiography fluoroscopic images. In patients who underwent adrenal vein sampling (18 without, 23 with image fusion-augmented angiography), image fusion-augmented angiography increased the success rate of right adrenal vein cannulation (55.6% to 87.0%; p = .04) and reduced fluoroscopy time (23.7 to 16.3 minutes; p = .03) and dose area product (532,195 to 91,403 mGy ∙ cm2; p = .006).

A Randomized Trial on the Effect of Phosphate Reduction on Vascular End Points in CKD (IMPROVE-CKD).

BACKGROUND: Hyperphosphatemia is associated with increased fibroblast growth factor 23 (FGF23), arterial calcification, and cardiovascular mortality. Effects of phosphate-lowering medication on vascular calcification and arterial stiffness in CKD remain uncertain. METHODS: To assess the effects of non-calcium-based phosphate binders on intermediate cardiovascular markers, we conducted a multicenter, double-blind trial, randomizing 278 participants with stage 3b or 4 CKD and serum phosphate >1.00 mmol/L (3.10 mg/dl) to 500 mg lanthanum carbonate or matched placebo thrice daily for 96 weeks. We analyzed the primary outcome, carotid-femoral pulse wave velocity, using a linear mixed effects model for repeated measures. Secondary outcomes included abdominal aortic calcification and serum and urine markers of mineral metabolism. RESULTS: A total of 138 participants received lanthanum and 140 received placebo (mean age 63.1 years; 69% male, 64% White). Mean eGFR was 26.6 ml/min per 1.73 m2; 45% of participants had diabetes and 32% had cardiovascular disease. Mean serum phosphate was 1.25 mmol/L (3.87 mg/dl), mean pulse wave velocity was 10.8 m/s, and 81.3% had abdominal aortic calcification at baseline. At 96 weeks, pulse wave velocity did not differ significantly between groups, nor did abdominal aortic calcification, serum phosphate, parathyroid hormone, FGF23, and 24-hour urinary phosphate. Serious adverse events occurred in 63 (46%) participants prescribed lanthanum and 66 (47%) prescribed placebo. Although recruitment to target was not achieved, additional analysis suggested this was unlikely to have significantly affected the principle findings. CONCLUSIONS: In patients with stage 3b/4 CKD, treatment with lanthanum over 96 weeks did not affect arterial stiffness or aortic calcification compared with placebo. These findings do not support the role of intestinal phosphate binders to reduce cardiovascular risk in patients with CKD who have normophosphatemia. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: Australian Clinical Trials Registry, ACTRN12610000650099.

Is point of care renal function testing reliable screening pre-IV contrast administration?

PURPOSE: Intravenous iodinated contrast is a commonly used diagnostic aid to improve image quality on computed tomography. There exists a small risk of post-contrast acute kidney injury in patients receiving IV contrast. One of the biggest risk factors for developing PC-AKI is the presence of pre-existing renal dysfunction, making it important to measure the renal function prior to contrast administration. Point of care (POC) devices offer a quick estimation of renal function, potentially improving workflows in radiology departments. METHOD: Two POC devices were evaluated, the Nova StatSensor and Abbott iSTAT. Patients undergoing routine radiological investigations had blood collected and analysed by a POC method and the laboratory method (Beckman AU5800). The two values were analysed and compared. Renal function was calculated using eGFR via the CKD-EPI result. eGFR values were stratified as high risk (eGFR < 30), moderate risk (eGFR 30-59) and low risk (eGFR ≥ 60). RESULTS: One hundred eighty-six patients were included in the study. One hundred one patients underwent the Abbott iSTAT analysis, 139 patients underwent Nova StatSensor analysis, and 53 had both. Statistical analysis revealed that the StatSensor R2 value was 0.77, and coefficient variation was 10.65%. iSTAT had a R2 value of 0.83 and coefficient variation of 7.36%. The POC devices did not miss any high-risk patients but underreported eGFR values in certain patients. CONCLUSION: POC devices are moderately accurate at detecting renal impairment in patients undergoing radiological investigations. They seem to be a good screening tool; however, any low eGFR values should be further examined.

Utility of adrenocorticotropic hormone in adrenal vein sampling despite the occurrence of discordant lateralization.

BACKGROUND: Adrenal vein sampling (AVS) is crucial for accurate lateralization of aldosterone excess but it is technically challenging due to the difficulty of adrenal vein cannulation. The use of adrenocorticotropic hormone (ACTH) to improve cannulation success is controversial and can lead to discordant lateralization outcomes. OBJECTIVE: To evaluate the utility of ACTH in two centres with different levels of AVS expertise and formulate a strategy for interpreting discordant results. DESIGN: A retrospective cross-sectional analysis of AVS results and postoperative patient outcomes. SETTING: Two large tertiary hospitals with harmonized AVS protocols where adrenal venous samples are collected both before and after ACTH stimulation. MEASUREMENTS: Cannulation success (measured by selectivity index, SI), lateralization (measured by lateralization index, LI) and postoperative biochemical cure. RESULTS: Number of AVS procedures judged to have successful bilateral adrenal vein cannulation increased from 53% pre- to 73% post-ACTH. The increase in cannulation success was significantly higher in centre where AVS was performed by multiple radiologists with a lower basal success rate. In both centres, the proportion of cases deemed to display lateralization significantly decreased with the use of ACTH (70% pre- to 52% post-ACTH). Based on postoperative outcomes of patients with discordant results who underwent unilateral adrenalectomy, the combination of LI >3 pre-ACTH and LI >2 post-ACTH was predictive of a biochemical cure. CONCLUSION: Adrenocorticotropic hormone can increase the rate of cannulation success during AVS at the expense of reduced lateralization. The criteria for lateralization should be carefully determined based on local data when ACTH is used.

Deposition Behavior of Polyaniline on Carbon Nanofibers by Oxidative Chemical Vapor Deposition.

Oxidative chemical vapor deposition (oCVD) offers unique advantages as a liquid-free processing technique in synthesizing and integrating conducting polymers, including polyaniline (PANI), by enabling conformal coatings onto nanostructured substrates, like carbon nanofibers. With relatively thick nanofiber mats, the challenge is to ensure uniform coating thickness through the porous substrates. Here, the substrate temperature during oCVD is found to be a primary factor influencing PANI coating uniformity. Coating uniformity is enhanced by operating at a higher substrate temperature, where monomer adsorption is believed to be limiting relative to intrinsic reaction kinetics. Also, a higher substrate temperature leads to significantly less PANI oligomers and more PANI in the emeraldine oxidation state. A systematic study of oCVD kinetics with substrate temperature shows a reaction-limited regime at lower substrate temperatures with an activation energy of 12.0 kJ/mol, which is believed to be controlled by the self-catalyzed PANI polymerization reaction that transitions at higher substrate temperatures above 90 °C to an adsorption-limited regime as indicated by a negative activation energy of -18.8 kJ/mol. Overall, by operating within an adsorption-limited oCVD regime, more uniform oCVD PANI coatings on electrospun carbon nanofiber mats have been achieved.

Monteggia fracture: an easy fracture to miss.

PURPOSE: To assess the incidence of missed Monteggia fracture by radiologists and bedside clinicians (emergency and orthopaedic doctors) at a tertiary hospital. METHODS: A comprehensive search was conducted on Picture Archiving and Communication System (PACS) and electronic medical records (EMR) between Jan 2010 and April 2019. All consecutive paediatric and adult patients who presented to the emergency department with the diagnosis of Monteggia fracture were included. The patient's emergency presentation medical notes and trauma film reports were compared. Most emergency presentations were discussed with orthopaedics; hence, this was combined as a single group (bedside clinician group). All images were blindly reviewed by a senior consultant radiologist. Results from the radiologist and bedside clinician groups were compared. RESULTS: Fifty-one patients were identified; 4 were excluded as they were not true Monteggia fracture on review. Forty-seven patients were included in the study (age range 3-70 years, mean age 15 years). Thirty-three patients (70%) were correctly diagnosed by both groups. Twelve patients (25.5%) had a missed diagnosis by the radiologist's group. Seven patients (14.9%) were missed by the bedside clinicians. Five patients (10.6%) were missed by both groups with fractures detected on re-presentations. The most commonly missed finding was a radial head dislocation/subluxation, followed by a subtle ulnar fracture (confirmed by periosteal reaction development on subsequent radiographs) and an ulnar plastic deformity. CONCLUSION: The Monteggia fracture is an important diagnosis, but it is not infrequently missed by radiologists and clinicians. Special attention to the radiocapitellar joint alignment and ulnar periosteum, and looking for a subtle ulnar fracture or plastic deformity would ensure correct diagnosis.

Multidisciplinary team clinic for vocal cord dysfunction directs therapy and significantly reduces healthcare utilization.

BACKGROUND AND OBJECTIVE: Multidisciplinary team (MDT) clinics use an integrated approach to individualize care of complex medical conditions. Vocal cord dysfunction (VCD) is a challenging condition that is likely to benefit from MDT clinics but this has not been researched. METHODS: A prospective observational cohort study of a novel VCD MDT clinic was conducted in patients with suspected VCD. Relevant questionnaires, medical history, physical examination, spirometry, dynamic computerized tomography (CT) larynx and laryngoscopy were utilized and patients were allocated to treatment pathways depending on putative diagnosis. Speech pathology intervention with laryngeal retraining (LR) was offered and if LR therapy failed botulinum toxin injection was offered. Primary outcome was reductions in healthcare utilization. RESULTS: Overall, 80 consecutive patients were included in analyses. A definitive diagnosis of VCD was made in 56 of 80 (70%) patients. After LR (n = 35), emergency department (ED)/hospital admissions declined significantly in the subsequent 12 months (P = 0.001). General practice visits also reduced (P < 0.001). Botulinum toxin injections were administered in 21 patients unresponsive to LR therapy and both general practice and ED/hospital visits declined (P < 0.001 and P = 0.01, respectively) after injection. CONCLUSION: A multidisciplinary approach to VCD confers benefit and can be used to allocate appropriate management leading to a reduction in healthcare utilization.

An Uncommon Presentation of a Primary Bone Tumor: Anti-AMPA (Anti-α-Amino-3-Hydroxy-5-Methyl-4-Isoxazolepropionic acid) Receptor Limbic/Paraneoplastic Encephalitis as a Presenting Feature of Ewing Sarcoma.

Anti-AMPA (anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor limbic encephalitis is a rare autoimmune syndrome. It can be associated with an underlying malignancy, such as lung, breast, or thymus. We are reporting a case of a 19-year-old patient who presented with a 2-week history of confusion and short-term memory loss. A magnetic resonance imaging of brain showed increased T2 hyperintensity within the hippocampi bilaterally. Cerebrospinal fluid analysis was positive for anti-AMPA receptor antibodies. A computed tomography revealed multiple pulmonary metastases as well as an expansile lucent and sclerotic lesion in the ilium, which was subsequently biopsied. Histopathology confirmed a diagnosis of Ewing sarcoma (ES). Fluorescence in situ hybridization testing of the specimen identified EWSR1 (22q12.2) signal rearrangements in 80% of cells scored. To date, this is the first case report describing anti-AMPA receptor limbic/paraneoplastic encephalitis as a presenting feature of ES. Although it is rare, the possibility of ES may be considered in young patients presenting with anti-AMPA receptor limbic encephalitis.

Are all urgent nephrostomies that urgent?

PURPOSE: To investigate if the presence of systemic inflammatory response syndrome (SIRS) in patients with urinary tract obstruction at time of presentation to the emergency department correlates with a subsequent positive urine culture and to determine if it could be used as a tool to predict the urgency of a percutaneous nephrostomy (PCN). The secondary aim of the study was to assess the incidence of in-hour and after-hour emergent PCNs performed in a tertiary center which has both interventional radiological and urological expertise. METHODS AND MATERIALS: Emergent adult PCN cases referred from the emergency department between 2011 and 2016 were identified retrospectively. Urine culture results, clinical features of SIRS, timing of procedure, and radiological findings were analyzed. RESULTS: A total of 110 patients met the inclusion criteria. There were a total of 60 male and 50 female patients with a mean age of 62 (age range 18-99 years). Ninety-two (83%) PCN patients were referred and performed on after-hours with the remaining 18 patients performed in-hours. There were 53 (48%) patients that met the criteria for obstruction with SIRS and 57 (52%) patients with obstruction without SIRS. The number of after-hours PCN performed in both groups was equal at 46 patients each. The most common cause of obstruction in the SIRS group was stone related in 31 (58%) patients. Whereas, the most common cause of obstruction in the non-SIRS group was due to malignancy in 26 (45%) cases. An elevated temperature and heart rate were the most common features of SIRS at 96 and 83% respectively in the SIRS group. An organism was isolated in 35 (67%) out of the 52 urine culture results obtained for the SIRS group. No organism was isolated in 42 (95%) out of the 44 urine culture results obtained in the non-SIRS group. Statistical analysis using Fisher's test revealed that the association between obstruction without SIRS and a negative urine culture result was statistically significant (p < 0.0001). CONCLUSION: A large percentage (50%) of PCN cases performed after-hours could have been performed during daytime hours instead due to the absence of infection. This would be in line with the practices of some centers that consider an infected obstructed kidney as the only absolute indication for emergent decompression overnight. The study also demonstrates that the absence of a SIRS in a patient with urinary tract obstruction correlates well with a negative urine culture result from the nephrostomy specimen which has a high negative predictive value for excluding pyonephrosis.

Expiratory central airway collapse in stable COPD and during exacerbations.

BACKGROUND: Tracheal obstruction resulting from expiratory tracheal deformation has been associated with respiratory symptoms and severe airway exacerbations. In chronic obstructive pulmonary disease (COPD), acute exacerbations (AECOPD) create large intrathoracic pressure swings which may increase tracheal deformation. Excessive central airway collapse (ECAC) may be diagnosed when the tracheal area on expiration is less than 50% of that on inspiration. The prevalence of ECAC in AECOPD and its temporal course have not been systematically studied. METHODS: We prospectively recruited healthy volunteers (n = 53), stable outpatients with COPD (n = 40) and patients with hospitalised acute exacerbations of COPD (AECOPD, n = 64). 17 of the AECOPD group returned for repeat evaluation when clinically well at 6-12 weeks. All subjects underwent dynamic 320-slice computed tomography of the larynx and trachea during tidal breathing, enabling quantitation of tracheal area and dimensions (mean ± SD). RESULTS: No healthy individuals had ECAC. The prevalence of ECAC in stable COPD and AECOPD was 35% and 39% respectively. Mean tracheal collapse did not differ between stable COPD (57.5 ± 19.8%), AECOPD (53.8 ± 19.3%) and in the subset who returned when convalescent (54.9 ± 17.2%). AECOPD patients with and without ECAC had similar clinical characteristics. CONCLUSIONS: Tracheal collapse in both stable and AECOPD is considerably more prevalent than in healthy individuals. ECAC warrants assessment as part of comprehensive COPD evaluation and management. Further studies should evaluate the aetiology of ECAC and whether it predisposes to exacerbations.

Suitability of N-propanoic acid spiropyrans and spirooxazines for use as sensitizing dyes in dye-sensitized solar cells.

This work deals with the fabrication and evaluation of color-changing dye-sensitized solar cells (DSSCs) that include N-propanoic acid-functionalized spiropyrans and spirooxazines as sensitizing dyes. We investigated the photophysical properties of these compounds in various solvents and pH conditions using UV-Vis spectroscopy, and their behavior on TiO2 photoanode surfaces using a combination of UV-Vis and FT-IR. Their performance as sensitizing dyes for DSSCs was also analyzed. This study revealed a number of unique properties for this class of compounds that affect their performance as both photochromic compounds and DSSC sensitizers, which allow for future creation of efficient photochromic DSSCs.