Photoinduced absorption spectroscopy (PIAS) study of water and chloride oxidation by a WO3 photoanode in acidic solution

The mechanisms of water and chloride oxidation by a WO3 photoanode are probed by photoinduced absorption spectroscopy (PIAS) coupled with transient photocurrent (TC) measurements. Linear sweep voltammograms (LSVs) and incident photon to current efficiencies (IPCEs) are obtained, in the water oxidation electrolyte (1 M HClO4) and chloride oxidation electrolyte (3.5 M NaCl in 1 M HClO4). Other work shows that the faradaic efficiency of water oxidation to O2 in 1 M HClO4 is ca. 1.0, and that for chloride oxidation to Cl2 in 3.5 M NaCl plus 1 M HClO4 is ca. 0.62. The PIAS/TC data reveals a 0.4 order dependency of the rate of water oxidation on the steady state concentration of photogenerated surface holes, [hs+]ss, and an approximately first order dependency of the rate of chloride oxidation on [hs+]ss. Associated mechanisms and rate determining steps for water and chloride oxidation at the photoanode surface that account for these reaction orders are proposed.

Kinetics of stearic acid destruction on TiO2 'self-cleaning' films revisited

The photocatalytic oxidation of stearic acid, SA, by O2 is a common test method used to assess the activity of new materials and underpins a standard test for self-cleaning activity. The kinetics of this process have been well-studied and are often interpreted using one of two simple models, which are revisited here in this overview. The first model is based on the common scenario of a SA layer on top of an all-photocatalyst layer which yields zero order kinetics, for which it is suggested that all the reaction sites are occupied by SA during the bulk of the photocatalytic process. An important, but rarely noted feature of this system is that the rate of SA removal depends directly upon the fraction of absorbed ultra-bandgap radiation, which suggests that the photocatalyst particles are extensively networked, thereby allowing the photogenerated electrons and holes to move rapidly and efficiently to the surface to effect the destruction of SA. The second kinetic model has been used to describe the first order kinetics of SA removal observed for mesoporous photocatalytic films comprised of isolated photocatalyst particles, in which the SA is inside (rather than on top) of the photocatalytic film, and is developed further here. It is shown that, contrary to previous reports, this model is not appropriate for porous photocatalytic films in which the particles are extensively networked, such as ones based on powders or sol-gel films, even though they too may exhibit decay kinetics where the order is > 0. The reason for the latter kinetics appears to be a distribution of reactivities through such films, i.e. high and low activity sites.

Flexible, disposable photocatalytic plastic films for the destruction of viruses

A thin, 30 μm, flexible, robust low-density polyethylene, LDPE, film, loaded with 30 wt% P25 TiO₂, is extruded and subsequently rendered highly active photocatalytically by exposing it to UVA (352 nm, 1.5 mW cm⁻²) for 144 h. The film was tested for anti-viral activity using four different viruses, namely, two strains of Influenza A Virus (IAV), WSN, and a recombinant PR8, encephalomyocarditis virus (EMCV), and SARS-CoV-2 (SARS2). The film was irradiated with either UVA radiation (352 nm, 1.5 mW cm⁻²; although only 0.25 mW cm⁻² for SARS2) or with light from a cool white fluorescent lamp (UVA irradiance: 365 nm, 0.047 mW cm⁻²). In all cases the films exhibited an average virus inactivation rate of >1.5log/h. In the case of SARS2, the rates were > 2log/h, with the rate determined using a dedicated, low intensity UVA source (0.25 mW cm⁻²) only 1.3 x's faster than that for a cool white lamp (UVA irradiance = 0.047 mW cm⁻²), which suggests that SARS2 is particularly prone to photocatalytic inactivation even under low UV irradiation conditions, such as found in a room lit with just white fluorescent tubes. This is the first example of a flexible, very thin, photocatalytic plastic film, produced by a scalable process (extrusion), for virus inactivation. The potential of such a film for use as a disposable, self-sterilising thin plastic material alternative to the common, non-photocatalytic, inert equivalent used currently for curtains, aprons and table coverings in healthcare is discussed briefly.

3D printed, plastic photocatalytic flow reactors for water purification

3D printing is known as a fast, inexpensive, reproducible method for producing prototypes but is also fast becoming recognised as a scalable, advanced manufacture process. Two types of lab-scale, 3D printed plastic, fixed-film, flow-through photocatalytic reactors are described, both of which are sinusoidal in shape, and only differ in that one has no baffles, reactor A, whereas the other has, reactor B. Both reactors are lined with a P25 TiO₂/polylactic acid (PLA) coating, which, after UVA pre-conditioning, is used to photocatalyse the bleaching of circulating aqueous solutions of either methylene blue, MB, or phenol, PhOH, repeatably, without any obvious loss of activity. The rate of the photocatalysed bleaching of MB exhibited by reactor B shows a much lower dependence upon flow rate than reactor A, due to the greater lateral mixing of the laminar flow streams produced by the baffles. The photonic efficiencies of reactor A for the photocatalysed bleaching of MB and PhOH were determined to be 0.025% and 0.052%, respectively, and the photocatalytic space-time yields (PSTY) to be 0.98 × 10^-4 and 1.49 × 10^-4 m³ of reaction solution.m^-3 reactor volume.day^-1.kW^-1, respectively. This is the first example of an all plastic, 3D printed photocatalytic reactor and demonstrates the advantages of 3D printing for prototyping. Given the 3D printing is a scalable process, possible potential areas of application are discussed briefly.

Evaluation of a prospective adverse event reporting system in interventional radiology

AIM

To assess the performance of a prospective adverse event (AE) reporting system.

MATERIALS AND METHODS

Four hundred and seventy-one consecutive arterial procedures were performed in 465 patients (median age, 65 years; interquartile range, 54-77; 276 men) over 2 years by four interventional radiologists at a single centre where clinical follow-up was not performed routinely by interventional radiology (IR). AEs were reported prospectively using a radiology information system or in interventional radiologists' electronic records and combined in a departmental listing of adverse events (DLAE). A retrospective medical record review was performed to identify a reference standard list of AEs for this observational cohort study. AEs were graded according to the Society of Interventional Radiology AE classification system. Descriptive statistics were calculated for the performance of the DLAE. A model comparing the rate of reporting of AEs with and without integration of clinical follow-up was tested for significance.

RESULTS

Thirty-eight of the 471 (8%) IR procedures had an AE according to the reference standard. The DLAE identified 20/38 (53%) of AEs (K=0.67 [good agreement], 95% confidence interval [CI] agreement=0.53-0.81; p=0.0001; sensitivity 52.6% [95% CI, 36-69%], specificity 100% [95% CI, 99-100%], positive predictive value [PPV] 100%, negative predictive value [NPV] 96 [95% CI, 94.5-97%], accuracy 96% [95% CI, 94-97%]). The performance of the AE reporting system will improve with integration of clinical follow-up (p=0.0015).

CONCLUSION

A prospective AE reporting system without clinical integration will not detect all procedure complications.

Water oxidation by P25 TiO2 photoanodes in acidic solution

P25 TiO₂ photoanodes are used to photo-oxidise water in two different acids, 0.5 M H₂SO₄ and 1 M HClO₄. In the former acid, the linear sweep voltammogram, LSV, appears to exhibit two photocurrent waves, whilst only one in the latter. In 0.5 M H₂SO₄, the recorded LSV coupled with a low faradaic efficiency (0.58) for the photooxidation of water to O₂, f_O2, and a significant level of persulfate, f_S2O8 = 0.12, shows that the electrochemical kinetics are not simply those for water oxidation. In 1 M HClO₄, the LSV coupled with a high f_O2 value (0.91) suggest that the photocurrent is due to water oxidation. Photo-induced absorption spectroscopy, PIAS, measurements made using the P25 TiO₂ photoanode reveal a steady state absorbance change, ΔAbs_ss, associated with the steady-state concentration of surface accumulated holes, [h⁺]_ss, which varies with: (i) monitoring wavelength, with a peak at ca. 500 nm, and (ii) applied potential, flattening off at ca. 0.7 V vs Ag/AgCl. PIAS measurements, coupled with concomitant transient photocurrent (TC) measurements, on the P25 TiO₂ photoanode polarised at 1.3 v vs Ag/AgCl, in 1 M HClO₄, show that the oxidation of water is second order with respect the concentration of the surface-accumulated, photogenerated holes, [h⁺]_ss, which have a calculated turnover frequency of 19 s^-1, under 1 sun irradiation. This is the first reported example of the use of PIAS/TC to probe the photoelectrochemical kinetics exhibited by a mesoporous semiconductor photoanode derived from a powder, for water oxidation and the significance of such is discussed briefly.

Kinetics of the photocatalysed reduction of oxygen by CdS probed using photoinduced absorption spectroscopy (PIAS)

Photoinduced absorption spectroscopy, PIAS, is used to determine the order of reaction and so identify the rate determining step in the reduction of O₂ by a sacrificial electron donor, photocatalysed by a nanoparticular film of CdS. This is the first report on the use of PIAS to probe the kinetics of photocatalysis exhibited by a non-oxide semiconductor.

Probing P25 TiO2 photocatalysis using photoinduced absorption spectroscopy (PIAS)

Photoinduced absorption spectroscopy, PIAS, is used for the first time to probe the kinetics exhibited by the most commonly employed powder photocatalyst, P25 TiO2, in mesoporous film form, in the photocatalysed oxidation of a commonly used test organic pollutant, 4-chlorophenol, 4CP. The results show that PIAS can provide previously unobtainable, invaluable, direct kinetic, and mechanistic, information concerning photogenerated holes in powdered photocatalysts.

Radiologists are increasingly recommending follow-up of chest radiographs: a 10-year review

PURPOSE

To assess for changes in trends of GP chest radiograph reporting over a 10-year period and to assess if there has been a change in recommendations for follow-up.

METHODS

Retrospective study of an Irish tertiary referral center. The total number of GP-referred chest x-rays performed per year from 2007 to 2017 are recorded. One-hundred male/100 female GP-referred chest x-rays are chosen at random from NIMIS data for each of 2007, 2010, 2013, and 2017. Reports are analyzed with regard to abnormal findings, recommendation for follow-up, and yield of follow-up imaging.

RESULTS

There were 4917 GP CXRs performed in 2007, 4856 in 2010, 5561 in 2013, and 6492 in 2017. Follow-up was recommended in 17 studies(8.5%) in 2007, 19 studies(9.5%) in 2010, 22 studies(11%) in 2013, and 27 studies(13.5%) in 2017. Indications for follow-up recommendation were largely to ensure resolution of infection (52%) or for nodule surveillance (43%). There has been a notable increase in lung nodule follow-up, with suggested follow-ups increasing from 6 in 2007, to 7 in 2010, 9 in 2013, and 14 in 2017, an increase of 58%.

CONCLUSION

Along with the increase in the quantity of GP-referred chest radiographs over the past 10 years, suggestions for follow-up have increased, particularly for nodule surveillance. Reasons for this increase may include lack of availability of CT to GPs for lung cancer screening, insensitivity of plain radiographs to early cancer detection, and possible fear of litigation for missing lesions, making radiologists more cautious.

Combining in silico and in vitro models to inform cell seeding strategies in tissue engineering

The seeding density of therapeutic cells in engineered tissue impacts both cell survival and vascularization. Excessively high seeded cell densities can result in increased death and thus waste of valuable cells, whereas lower seeded cell densities may not provide sufficient support for the tissue in vivo, reducing efficacy. Additionally, the production of growth factors by therapeutic cells in low oxygen environments offers a way of generating growth factor gradients, which are important for vascularization, but hypoxia can also induce unwanted levels of cell death. This is a complex problem that lends itself to a combination of computational modelling and experimentation. Here, we present a spatio-temporal mathematical model parametrized using in vitro data capable of simulating the interactions between a therapeutic cell population, oxygen concentrations and vascular endothelial growth factor (VEGF) concentrations in engineered tissues. Simulations of collagen nerve repair constructs suggest that specific seeded cell densities and non-uniform spatial distributions of seeded cells could enhance cell survival and the generation of VEGF gradients. These predictions can now be tested using targeted experiments.

Diagnostic accuracy of SUVmax in predicting malignancy of supraclavicular lymph nodes from primary oesophageal cancer

PURPOSE

To determine the diagnostic accuracy and optimum cut-off value of SUVmax on PET to predict malignancy of supraclavicular lymph nodes (SCLNs) in patients with oesophageal carcinoma.

MATERIAL AND METHODS

All diagnosed cases of oesophageal cancer were retrospectively reviewed (2010-2016). Patients that had a confirmed diagnosis of oesophageal cancer with avid SCLNs on staging PET were included in the study. 33 SCLNs that subsequently underwent ultrasound guided biopsy for staging were analysed. The maximum uptake values (SUVmax) of the SCLNs and primary tumours were measured. A receiver operating characteristic (ROC) analysis was performed to determine the optimum cut off of SUVmax in predicting malignancy.

RESULTS

24/33 PET-detected SCLNs were malignant. ROC analysis identified the best nodal SUVmax cut-off to be 3.0. The diagnostic accuracy of PET was 76.0 % (sensitivity = 78.9 %, specificity = 66.6 %). For SCLNs with SUVmax > 3.0, PET showed a positive predictor value of 88.2 %; for SCLNs < 3.0, PET showed a negative predictor value of 50 %. The median SUVmax of pathologically negative and positive nodes were 2.8 (range 1.8-6.0) and 5.3 (range 1.9-13.4). The median primary tumour SUVmax was 13.8 (range 3.7-30.0). The SUVmax of metastatic lymph nodes were significant higher than those of benign lesions (p < 0.05).

CONCLUSION

Our study revealed an accuracy rate of 76 % for PET detected SCLNs in patients with oesophageal carcinoma. For SCLNs with SUVmax > 3.0, PET had a high PPV (88 %), which can minimize the need for further diagnostic tests.

Action spectra in semiconductor photocatalysis

Action spectra are an increasingly important part of semiconductor photocatalyst research, and comprise a plot of photonic efficiency, η, versus excitation wavelength, λ. The features and theory behind an ideal photocatalytic system are discussed, and used to identify: (i) the key aspect of an ideal action spectrum, namely: it is a plot of η vs. λ which has the same shape as that of the fraction of radiation absorbed by the semiconductor photocatalyst, f, versus λ and (ii) the key requirement when running an action spectrum, namely, that the initial rate of the photocatalytic process is directly proportional to incident photon flux, ρ, at wavelengths where η > 0. The Pt/TiO₂/MeOH system is highlighted as an example of a photosystem that yields an ideal action spectrum. Most photocatalytic systems exhibit non-ideal action spectra, mostly due to one or more of the following: light intensity effects, crystal phase effects, dye-sensitisation, dye photolysis, charge transfer complex, CTC, formation and localized surface plasmon radiation, LSPR, absorption by a deposited noble metal catalyst. Each of these effects is illustrated using examples taken from the literatures and discussed. A suggested typical protocol for recording the action spectrum and absorption/diffuse reflectance spectrum of a photocatalytic system is described. The dangers of using a dye to probe the activity of a photocatalysts are also discussed, and a possible way to avoid this, via reductive photocatalysis, is suggested.

An allogeneic 'off the shelf' therapeutic strategy for peripheral nerve tissue engineering using clinical grade human neural stem cells

Artificial tissues constructed from therapeutic cells offer a promising approach for improving the treatment of severe peripheral nerve injuries. In this study the effectiveness of using CTX0E03, a conditionally immortalised human neural stem cell line, as a source of allogeneic cells for constructing living artificial nerve repair tissue was tested. CTX0E03 cells were differentiated then combined with collagen to form engineered neural tissue (EngNT-CTX), stable aligned sheets of cellular hydrogel. EngNT-CTX sheets were delivered within collagen tubes to repair a 12 mm sciatic nerve injury model in athymic nude rats. Autologous nerve grafts (autografts) and empty tubes were used for comparison. After 8 weeks functional repair was assessed using electrophysiology. Further, detailed histological and electron microscopic analysis of the repaired nerves was performed. Results indicated that EngNT-CTX supported growth of neurites and vasculature through the injury site and facilitated reinnervation of the target muscle. These findings indicate for the first time that a clinically validated allogeneic neural stem cell line can be used to construct EngNT. This provides a potential 'off the shelf' tissue engineering solution for the treatment of nerve injury, overcoming the limitations associated with nerve autografts or the reliance on autologous cells for populating repair constructs.

The value of multimodality imaging in the investigation of a PSA recurrence after radical prostatectomy in the Irish hospital setting

INTRODUCTION

The diagnostic evaluation of a PSA recurrence after RP in the Irish hospital setting involves multimodality imaging with MRI, CT, and bone scanning, despite the low diagnostic yield from imaging at low PSA levels. We aim to investigate the value of multimodality imaging in PC patients after RP with a PSA recurrence.

METHODS

Forty-eight patients with a PSA recurrence after RP who underwent multimodality imaging were evaluated. Demographic data, postoperative PSA levels, and imaging studies performed at those levels were evaluated.

RESULTS

Eight (21%) MRIs, 6 (33%) CTs, and 4 (9%) bone scans had PCa-specific findings. Three (12%) patients had a positive MRI with a PSA <1.0 ng/ml, while 5 (56%) were positive at PSA ≥1.1 ng/ml (p = 0.05). Zero patient had a positive CT TAP at a PSA level <1.0 ng/ml, while 5 (56%) were positive at levels ≥1.1 ng/ml (p = 0.03). Zero patient had a positive bone at PSA levels <1.0 ng/ml, while 4 (27%) were positive at levels ≥1.1 ng/ml (p = 0.01).

CONCLUSION

The diagnostic yield from multimodality imaging, and isotope bone scanning in particular, in PSA levels <1.0 ng/ml, is low. There is a statistically significant increase in the frequency of positive findings on CT and bone scanning at PSA levels ≥1.1 ng/ml. MRI alone is of investigative value at PSA <1.0 ng/ml. The indication for CT, MRI, or isotope bone scanning should be carefully correlated with the clinical question and how it will affect further management.

Impact of surgeon laparoscopic training and case volume of laparoscopic surgery on conversion during elective laparoscopic colorectal surgery

AIM

The study aimed to determine whether laparoscopic volume and type of training influence conversion during elective laparoscopic colorectal surgery.

METHOD

An Institutional Review Board-approved prospective database was reviewed for patients who underwent colorectal resection, performed by six colorectal surgeons, for all diagnoses from 2009 to 2014. Surgeons were designated as laparoscopic- or open-trained based on formal laparoscopic colorectal surgery training, and were classified as low laparoscopic volume (LLV) (i.e. had performed < 100 laparoscopic procedures) or high laparoscopic volume (HLV) (i.e. had performed ≥ 100 laparoscopic procedures). Technique was laparoscopic, open or converted (pre-emptive or reactive). Conversion was compared among three groups: LLV, laparoscopic trained (group A); LLV, open trained (group B); and HLV, open trained (group C).

RESULTS

In total, 159/567 procedures were open and 408 laparoscopic procedures were attempted. Of the 408 laparoscopic procedures, 73 were converted. Among the 567 patients [mean age: 56 ± 17 years (44% male)], the overall conversion rate was 13% (73/567), including 75% pre-emptive and 25% reactive. Conversion rates for groups A, B and C were 17.9%, 42.6% and 14.3%, respectively. Significantly higher conversion was seen in group B compared with group C (P = 0.01), but not between group A and group C (P = 0.85) or between group B and group A (P = 0.11). Converted patients were older (P < 0.001), with lower rates of proctectomy (P = 0.007), higher rates of anastomosis (P < 0.001) and higher body mass index (BMI) (P < 0.001). After adjusting for patient and surgeon factors, training type was not associated with conversion (P = 0.15). Compared with successful laparoscopy, converted patients had a significantly higher incidence of ileus (P < 0.001), length of stay (P = 0.002), time to flatus (OR = 3.21, P < 0.001) and time to solids (P < 0.001). Converted patients experienced increased morbidity.

CONCLUSION

Training is not associated with conversion. Rather, HLV surgeons, regardless of training, convert less frequently than do LLV surgeons.

Comparing Normothermic Machine Perfusion Preservation With Different Perfusates on Porcine Livers From Donors After Circulatory Death

The utilization of normothermic machine perfusion (NMP) may be an effective strategy to resuscitate livers from donation after circulatory death (DCD). There is no consensus regarding the efficacy of different perfusates on graft and bile duct viability. The aim of this study was to compare, in an NMP porcine DCD model, the preservation potential of three different perfusates. Twenty porcine livers with 60 min of warm ischemia were separated into four preservation groups: cold storage (CS), NMP with Steen solution (Steen; XVIVO Perfusion Inc., Denver, CO), Steen plus red blood cells (RBCs), or whole blood (WB). All livers were preserved for 10 h and reperfused to simulate transplantation for 24 h. During preservation, the NMP with Steen group presented the highest hepatocellular injury. At reperfusion, the CS group had the lowest bile production and the worst hepatocellular injury compared with all other groups, followed by NMP with Steen; the Steen plus RBC and WB groups presented the best functional and hepatocellular injury outcomes, with WB livers showing lower aspartate aminotransferase release and a trend toward better results for most parameters. Based on our results, a perfusate that contains an oxygen carrier is most effective in a model of NMP porcine DCD livers compared with Steen solution. Specifically, WB-perfused livers showed a trend toward better outcomes compared with Steen plus RBCs.

Detecting internet search activity for mouth cancer in Ireland

Mouth Cancer Awareness Day in Ireland was launched in September 2010 by survivors of the disease to promote public awareness of suspicious signs of oral cancer and to provide free dental examinations. To find out whether its introduction had increased public interest in the disease, we used Google Trends to find out how often users in Ireland had searched for "oral cancer" and "mouth cancer" across all Google domains between January 2005 and December 2013. The number of internet searches for these cancers has increased significantly (p <0.001) and has peaked each September since the awareness day was launched in 2010. More people searched for "mouth cancer" than for "oral cancer". These findings may have valuable clinical implications, as an increase in public awareness of mouth cancer could result in earlier presentation and better prognosis.

Wireless rotating disk electrode (wRDE) for assessing heterogeneous water oxidation catalysts (WOCs)

A novel method for assessing the activity of a powdered water oxidation catalyst (WOC) is described, utilising an easily-prepared wireless rotating disc electrode of the WOC, thereby allowing its activity to be probed, via the observed kinetics of water oxidation by Ce(iv) ions, and so provide invaluable electrochemical information.

The reporting of research ethics committee approval and informed consent in otolaryngology journals

OBJECTIVES

Medical research involving human subjects must follow ethical standards as outlined in the Declaration of Helsinki of the World Medical Association. The aim of this study was to assess the frequency of reporting of informed consent and regional ethical committee (REC) approval in all reports of trials published in the major European Otolaryngology journals.

DESIGN

Review of all clinical research articles published online in the calendar year 2012.

SETTING

Three leading European Otolaryngology journals.

PARTICIPANTS

Clinical Otolaryngology, The Journal of Laryngology and Otology and The European Achieves of Oto-Rhino-Laryngology.

MAIN OUTCOME MEASURES

Evaluate the incidence of reporting of REC approval and informed consent.

RESULTS

Of the 767 articles reviewed, 401 met the inclusion criteria (manuscripts reporting human subjects, human tissue or identifiable personal data research which require ethical approval). 49.9% lacked a statement of REC approval and 42.9% lacked disclosure of informed consent. Articles that did not state REC approval were associated with not stating informed consent (P < 0.05).

CONCLUSION

Articles that lack explicit statements of REC approval and informed consent are frequent and continue to be published in major otolaryngology journals.

A smart ink for the assessment of low activity photocatalytic surfaces

The azo dye, basic blue 66 (BB66) is used in a photocatalyst activity indicator ink (paii) to assess the activity of low activity photocatalytic surfaces, such as commercial photocatalytic tiles and silicone contaminated self-cleaning glass. The BB66 paii is shown to respond much faster than a previously reported, resazurin (Rz) based paii, i.e. the use of a BB66 paii on low activity self-cleaning tiles was found to be >6 times faster than the Rz paii. The BB66 paii is also shown to be effective at assessing the activity of piece of commercial self-cleaning glass contaminated with a coating of silicone, on which the Rz ink, in contrast, failed to show any significant change in colour over the same time period.

What is the role of 'the letter to the editor'?

The letter to the editor plays a dual role in the literature. It serves a corrective critical function but also has the capacity to spread and share knowledge. We sought to identify the role and theme of letters to the editor published in four leading otorhinolaryngology journals, to elicit how well this form of communication is being utilised. All letters to the editor published in; Clinical Otolaryngology, The Laryngoscope, The European Archives of Otorhinolarygnology and The Journal of Laryngology and Otology, for the year 2012, were examined and the individual journal guidelines for submission of letters were noted. Seventeen different countries produced a total of 92 letters for the year 2012. The majority of letters originated from Otolaryngology/Head and Neck departments (78 %). Clinical Otolaryngology contributed to 58 % of total letters, of which 55 % were unrelated to original journal material (n = 29). The Laryngoscope published letters solely in response to original journal material. The Journal of Laryngology and Otology was the only journal to index letters with their corresponding article. More letters agreeing (49 %) than disagreeing (32 %) were published, with the remaining letters either clarifying or ignoring issues raised. Letters to the editor serve two main purposes; post-publication peer review and sharing experiences with fellow readers. Both are equally important in maintaining journals' high standards. Indexing needs to be improved otherwise valuable comment does not endure while the original manuscript's message lives on.

DSSC anchoring groups: a surface dependent decision

Electrodes in dye sensitised solar cells are typically nanocrystalline anatase TiO2 with a majority (1 0 1) surface exposed. Generally the sensitising dye employs a carboxylic anchoring moiety through which it adheres to the TiO₂ surface. Recent interest in exploiting the properties of differing TiO₂ electrode morphologies, such as rutile nanorods exposing the (1 1 0) surface and anatase electrodes with high percentages of the (0 0 1) surface exposed, begs the question of whether this anchoring strategy is best, irrespective of the majority surface exposed. Here we address this question by presenting density functional theory calculations contrasting the binding properties of two promising anchoring groups, phosphonic acid and boronic acid, to that of carboxylic acid. Anchor-electrode interactions are studied for the prototypical anatase (1 0 1) surface, along with the anatase (0 0 1) and rutile (1 1 0) surfaces. Finally the effect of using these alternative anchoring groups to bind a typical coumarin dye (NKX-2311) to these TiO₂ substrates is examined. Significant differences in the binding properties are found depending on both the anchor and surface, illustrating that the choice of anchor is necessarily dependent upon the surface exposed in the electrode. In particular the boronic acid is found to show the potential to be an excellent anchor choice for electrodes exposing the anatase (0 0 1) surface.

Catalyst-free photoredox addition-cyclisations: exploitation of natural synergy between aryl acetic acids and maleimide

Suitably functionalised carboxylic acids undergo a previously unknown photoredox reaction when irradiated with UVA in the presence of maleimide. Maleimide was found to synergistically act as a radical generating photoxidant and as a radical acceptor, negating the need for an extrinsic photoredox catalyst. Modest to excellent yields of the product chromenopyrroledione, thiochromenopyrroledione and pyrroloquinolinedione derivatives were obtained in thirteen preparative photolyses. In situ NMR spectroscopy was used to study each reaction. Reactant decay and product build-up were monitored, enabling reaction profiles to be plotted. A plausible mechanism, whereby photo-excited maleimide acts as an oxidant to generate a radical ion pair, has been postulated and is supported by UV/Vis. spectroscopy and DFT computations. The radical-cation reactive intermediates were also characterised in solution by EPR spectroscopy.

Assessment of the activity of photocatalytic paint using a simple smart ink designed for high activity surfaces

The use of an acid violet 7 (AV7) smart ink to assess the activity of photocatalytic paint is demonstrated. A linear correlation is established between the change in oxidized dye concentration, as measured by diffuse reflectance, and the change in the green component of the RGB color values, obtained using a portable hand-held scanner, suggesting that such tests can be monitored easily using an inexpensive piece of hand-held office equipment, as opposed to an expensive lab-based instrument, such as a diffuse reflectance UV/vis spectrophotometer. The bleaching of the AV7 follows first order kinetics, at a rate that is linearly dependent upon the UVA irradiance (0.30-3.26 mW cm(-2)). A comparison of relative rate of bleaching of the AV7 ink with the relative rate of removal of NOx, as determined using the ISO test (ISO 22197-1:2007), established a linear relationship between the two sets of results and the relevance of this correlation is discussed briefly.

Adsorption and photocatalytic and photosensitised bleaching of acid orange 7 on multilayer mesoporous films of TiO2

A series of mesoporous films of titania of different thicknesses are prepared and their surface areas and porosities determined by physical adsorption using Kr as the adsorbate. The amounts of acid orange 7 (AO7) adsorbed by these films are found to be proportional to their measured surface areas and so the possibility of using this as a method of determining the surface area of thin titania films is discussed. The initial rates of UV-driven photocatalytic- and visible-driven photosensitised-bleaching of AO7 in solution, upon UVA and visible light irradiation, respectively, are also directly dependent upon the measured surface areas of the titania films. The quantum efficiencies for the UV photocatalytic- and visible photosensitised-bleaching of AO7 by the thickest of the AO7 films were estimated to be 0.08 and 0.01%, respectively.

Fatal lymphoproliferative disease associated with a novel gammaherpesvirus in a captive population of common marmosets

BACKGROUND AND PURPOSE

Callitrichids (marmosets and tamarins) are extremely susceptible to experimental tumor induction by herpesviruses native to other primate species. A colony of common marmosets developed a syndrome of weight loss, inappetence, diarrhea, and in several animals, palpable abdominal masses.

METHODS

Marmosets in the colony were subjected to histologic examination and serologic testing for Epstein-Barr virus (EBV). The DNA from tumors that developed in the marmosets was subjected to consensus primer polymerase chain reaction (PCR) analysis designed to amplify conserved regions of herpesvirus genomes.

RESULTS

The mesenteric lymph nodes and intestinal mucosa were consistently infiltrated by principally B lymphocytes, which often obliterated the normal architecture. Of 84 clinically normal marmosets, 52 were seropositive for EBV. The tumor DNA contained previously unreported herpesvirus sequences closely related to but distinct from those of EBV, Herpesvirus papio, and these lymphocryptovirus, a novel gammaherpesvirus. Results of PCR analysis of circulating lymphocytes from EBV-positive, clinically normal marmosets were negative for EBV antibodies and were positive for marmoset lymphocryptovirus; PCR analysis of circulating lymphocytes from EBV-negative marmosets yielded negative results for EBV and this novel marmoset lymphocryptovirus.

CONCLUSION

This novel gammaherpesvirus possibly associated with tumor development may have important management implications for captive callitrichids.

Rib biopsy technique for cortical bone evaluation in rhesus monkeys (Macaca mulatta)

Old World primates are often studied to model human skeletal physiology. An important advantage of monkeys over other animal models (i.e., rodents) is the presence of cortical bone Haversian remodeling. Seventy-five female rhesus monkeys (Macaca mulatta) were subjected to bone biopsy. With monkeys in lateral decubitus position, the tenth rib was surgically exposed and freed from periosteum by use of careful sharp and blunt dissection. The rib section was resected, using bone cutters, and the surgical wound was closed. This procedure was repeated for the contralateral rib at a later time point in 65 monkeys. There was no mortality or appreciable morbidity. The bone specimens were (mean +/- SD) 2.50 +/- 0.25 cm long, with 5.5 +/- 1.0 mm2 total cross-sectional area. They were adequate for histologic, immunohistochemical, and quantitative histomorphometric examinations. Prevalence of pneumothorax was approximately 8.0% for the 140 procedures. This complication was immediately and successfully corrected by insertion of a small thoracic tube, evacuation of pneumothorax, and closure of the incision. This well-tolerated, repeatable procedure yields excellent specimens for performance of cortical bone histologic examination without euthanasia, allowing longitudinal evaluation.

Orofacial pain in patients with sickle cell disease

The potential danger of low oxygen tension to patients with sickle cell disease is widely known. However, less well known is the phenomenon of patients with sickle cell disease presenting with toothache in the absence of any dental pathology. This study investigated the experience of orofacial pain in three matched groups, comprising patients with sickle cell disease, sickle cell trait and patients with no known blood dyscrasia. There were no differences in pain experience between those groups with sickle cell trait and no known blood dyscrasia. The sickle cell disease patients experienced significantly more orofacial pain in the same 12-month period than the other groups. The pain was also more frequent and of longer duration. In two-thirds of those sickle cell disease patients who experienced toothache, no dental pathology was found, in direct contrast to patients with trait or no known blood dyscrasia. Sickling of blood cells within the dental pulp in a sickle cell crisis may result in pain within teeth. These patients may then present as experiencing toothache in the absence of any dental pathology. General dental practitioners should be aware of this phenomenon when providing care for these susceptible patients.