Platinized Titanium as Alternative Cost-Effective Anode for Efficient Kolbe Electrolysis in Aqueous Electrolyte Solutions.

Five commercial materials were assessed for electrochemical conversion of n-hexanoic acid by Kolbe electrolysis. Platinized titanium performed best, achieving a coulombic efficiency (CE) of 93.1±6.7 % (n=6) for the degradation of n-hexanoic acid and 48.3±3.2 % (n=6) for the production of n-decane, which is close to the performance of pure platinum (89.7±14.4 and 55.5±3.5 %; n=6). 56.7 mL liquid fuel was produced per mole n-hexanoic acid, converting to an energy demand of 6.66 kWh and 1.22 € per L. Using optical profilometry and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, it was shown that the degree of coverage of the titanium surface with platinum played the most important role. An uncovered surface of as little as 1-3 % already led to a deterioration of the CE of approximately 50 %. Using platinized titanium requires >36 times less capital expenditure at only <10 % increased operational expenditure; an electrode lifetime of 10000 h can be expected.

Computed Tomography Volumetry in Preoperative Living Kidney Donor Assessment for Prediction of Split Renal Function.

BACKGROUND: Transplant centers commonly evaluate split renal function (SRF) with Tc-99m-mercapto-acetyltriglycin (MAG3) scintigraphy in living kidney donation. Alternatively, the kidney volume can be measured based on predonation CT scans. The aim of this study was to identify the most accurate CT volumetry technique for SRF and the prediction of postdonation kidney function (PDKF). METHODS: Three CT volumetry techniques (modified ellipsoid volume [MELV], smart region of interest [ROI] volume, renal cortex volume [RCV]) were performed in 101 living kidney donors. Preoperation CT volumetric SRF was determined and compared with MAG3-SRF, postoperation donor kidney function, and graft function. RESULTS: The correlation between donors predonation total kidney volume and predonation kidney function was the highest for RCV (0.58 with creatine clearance, 0.54 with estimated glomerular filtration rate-Cockcroft-Gault). The predonation volume of the preserved kidney was (ROI, MELV, RCV) 148.0 ± 29.1 cm, 151.2 ± 35.4 and 93.9 ± 25.2 (P < 0.005 MELV vs RCV and ROI vs RCV). Bland-Altman analysis showed agreement between CT volumetry SRF and MAG3-SRF (bias, 95% limits of agreement: ROI vs MAG3 0.4%, -7.7% to 8.6%; MELV vs MAG3 0.4%, -8.9% to 9.7%; RCV vs MAG3 0.8%, -9.1% to 10.7%). The correlation between predonation CT volumetric SRF of the preserved kidney and PDKF at day 3 was r = 0.85 to 0.88, between MAG3-SRF and PDKF (r = 0.84). The difference of predonation SRF between preserved and donated kidney was the lowest for ROI and RCV (median, 3% and 4%; 95th percentile, 9% and 13%). CONCLUSIONS: Overall renal cortex volumetry seems to be the most accurate technique for the evaluation of predonation SRF and allows a reliable prediction of donor's PDKF.

Neoadjuvant treatment for advanced esophageal cancer: response assessment before surgery and how to predict response to chemoradiation before starting treatment.

Patients with advanced esophageal cancer (T3-4, N) have a poor prognosis. Chemoradiation or chemotherapy before esophagectomy with adequate lymphadenectomy is the standard treatment for patients with resectable advanced esophageal carcinoma. However, only patients with major histopathologic response (regression to less than 10% of the primary tumor) after preoperative treatment will have a prognostic benefit of preoperative chemoradiation. Using current therapy regimens about 40% to 50% of the patients show major histopathological response. The remaining cohort does not benefit from this neoadjuvant approach but might benefit from earlier surgical resection. Therefore, it is an aim to develop tools for response prediction before starting the treatment and for early response assessment identifying responders. The current review discusses the different imaging techniques and the most recent studies about molecular markers for early response prediction. The results show that [(18)F]-fluorodeoxyglucose-positron emission tomography (FDG-PET) has a good sensitivity but the specificity is not robust enough for routine clinical use. Newer positron emission tomography detector technology, the combination of FDG-PET with computed tomography, additional evaluation criteria and standardization of evaluation may improve the predictive value. There exist a great number of retrospective studies using molecular markers for prediction of response. Until now the clinical use is missing. But the results of first prospective studies are promising. A future perspective may be the combination of imaging technics and special molecular markers for individualized therapy. Another aspect is the response assessment after finishing neoadjuvant treatment protocol. The different clinical methods are discussed. The results show that until now no non-invasive method is valid enough to assess complete histopathological response.

Confinement of two-dimensional rods in slit pores and square cavities.

Using Monte Carlo simulation, we analyse the behaviour of two-dimensional hard rods in four different types of geometric confinement: (i) a slit pore where the particles are confined between two parallel walls with homeotropic anchoring; (ii) a hybrid slit pore formed by a planar and a homeotropic wall; square cavities that frustrate the orientational order by imposing either (iii) homeotropic or (iv) planar wall anchoring. We present results for the state diagram as a function of the packing fraction and the degree of confinement. Under extreme confinement, unexpected states appear with lower symmetries than those of the corresponding stable states in bulk, such as the formation of states that break the anchoring constraints or the symmetry imposed by the surfaces. In both types of square cavities, the particles form disclinations at intermediate densities. At high densities, however, the elastic stress is relaxed via the formation of domain walls where the director rotates abruptly by 90°.

Visual assessment of dopaminergic degeneration pattern in 123I-FP-CIT SPECT differentiates patients with atypical parkinsonian syndromes and idiopathic Parkinson's disease.

The aim of this study was to investigate whether visual assessment of (123)I-N-ω-fluoropropyl-2ß-carbomethoxy-3ß-(4-iodophenyl)nortropan ((123)I-FP-CIT) single photon emission computed tomography (SPECT) in addition to quantitative analyses can help to differentiate idiopathic Parkinson's disease (PD) from atypical parkinsonian syndromes (APS). From a consecutive series of patients examined with (123)I-FP-CIT SPECT (n = 190) over a three-year period we identified 165 patients with a clinical diagnosis of PD (n = 120) or APS (n = 45). (123)I-FP-CIT SPECT results were analysed visually and quantitatively and compared for PD and APS and for the subgroup of patients with early PD and APS (disease duration <5 years). According to predefined visual patterns of dopaminergic degeneration the results were graded as normal (grade 5) or abnormal (grade 1-4), distinguishing a posterior-anterior degeneration pattern ("egg shape") from a global and severe degeneration pattern ("burst striatum"). Visual assessment of (123)I-FP-CIT SPECT showed significant different dopaminergic degeneration patterns for PD and APS patients. A grade 1 ("burst striatum") degeneration pattern was predominantly associated with APS patients. In contrast to that, a grade 2 (egg shape) degeneration pattern was the characteristic finding in PD patients. In a subgroup of patients with early disease, visual assessment with identification of the burst striatum degeneration pattern provided 90% positive predictive value and 99% specificity for the diagnosis of APS. Quantitative analysis of striatal binding ratios failed to depict these different degeneration patterns in PD and APS patients. Visual assessment of the pattern of dopaminergic loss in (123)I-FP-CIT SPECT shows different patterns of dopaminergic degeneration for PD and APS patients. Therefore, it could provide valuable information to distinguish APS from PD patients, especially in early stages of disease. Within the first 5 years of disease, the occurrence of a burst striatum degeneration pattern has a high positive predictive value of APS.

GATE based Monte Carlo simulation of planar scintigraphy to estimate the nodular dose in radioiodine therapy for autonomous thyroid adenoma.

The recommended target dose in radioiodine therapy of solitary hyperfunctioning thyroid nodules is 300-400Gy and therefore higher than in other radiotherapies. This is due to the fact that an unknown, yet significant portion of the activity is stored in extranodular areas but is neglected in the calculatory dosimetry. We investigate the feasibility of determining the ratio of nodular and extranodular activity concentrations (uptakes) from post-therapeutically acquired planar scintigrams with Monte Carlo simulations in GATE. The geometry of a gamma camera with a high energy collimator was emulated in GATE (Version 5). A geometrical thyroid-neck phantom (GP) and the ICRP reference voxel phantoms "Adult Female" (AF, 16ml thyroid) and "Adult Male" (AM, 19ml thyroid) were used as source regions. Nodules of 1ml and 3ml volume were placed in the phantoms. For each phantom and each nodule 200 scintigraphic acquisitions were simulated. Uptake ratios of nodule and rest of thyroid ranging from 1 to 20 could be created by summation. Quantitative image analysis was performed by investigating the number of simulated counts in regions of interest (ROIs). ROIs were created by perpendicular projection of the phantom onto the camera plane to avoid a user dependant bias. The ratio of count densities in ROIs over the nodule and over the contralateral lobe, which should be least affected by nodular activity, was taken to be the best available measure for the uptake ratios. However, the predefined uptake ratios are underestimated by these count density ratios: For an uptake ratio of 20 the count ratios range from 4.5 (AF, 1ml nodule) to 15.3 (AM, 3ml nodule). Furthermore, the contralateral ROI is more strongly affected by nodular activity than expected: For an uptake ratio of 20 between nodule and rest of thyroid up to 29% of total counts in the ROI over the contralateral lobe are caused by decays in the nodule (AF 3 ml). In the case of the 1ml nodules this effect is smaller: 9-11% (AF) respectively 7-8% (AM). For each phantom, the dependency of count density ratios upon uptake ratios can be modeled well by both linear and quadratic regression (quadratic: r(2)>0.99), yielding sets of parameters which in reverse allow the computation of uptake ratios (and thus dose) from count density ratios. A single regression model obtained by fitting the data of all simulations simultaneously did not provide satisfactory results except for GP, while underestimating the true uptake ratios in AF and overestimating them in AM. The scintigraphic count density ratios depend upon the uptake ratios between nodule and rest of thyroid, upon their volumes, and their respective position in a non-trivial way. Further investigations are required to derive a comprehensive rule to calculate the uptake or dose ratios based on post-therapeutic scintigraphy.

Monte Carlo computer simulations and electron microscopy of colloidal cluster formation via emulsion droplet evaporation.

We consider a theoretical model for a binary mixture of colloidal particles and spherical emulsion droplets. The hard sphere colloids interact via additional short-ranged attraction and long-ranged repulsion. The droplet-colloid interaction is an attractive well at the droplet surface, which induces the Pickering effect. The droplet-droplet interaction is a hard-core interaction. The droplets shrink in time, which models the evaporation of the dispersed (oil) phase, and we use Monte Carlo simulations for the dynamics. In the experiments, polystyrene particles were assembled using toluene droplets as templates. The arrangement of the particles on the surface of the droplets was analyzed with cryogenic field emission scanning electron microscopy. Before evaporation of the oil, the particle distribution on the droplet surface was found to be disordered in experiments, and the simulations reproduce this effect. After complete evaporation, ordered colloidal clusters are formed that are stable against thermal fluctuations. Both in the simulations and with field emission scanning electron microscopy, we find stable packings that range from doublets, triplets, and tetrahedra to complex polyhedra of colloids. The simulated cluster structures and size distribution agree well with the experimental results. We also simulate hierarchical assembly in a mixture of tetrahedral clusters and droplets, and find supercluster structures with morphologies that are more complex than those of clusters of single particles.

'Show me the money': financial incentives increase chlamydia screening rates among tertiary students: a pilot study.

BACKGROUND: We hypothesise that text-messaging and financial incentives would increase tertiary student participation in chlamydia screening. METHODS: A cross-sectional study was conducted over two phases on eight tertiary campuses during 2007. During Phase 1 (6 months) study activities were advertised through student organisations and media. Education and screening were offered during a range of student activities. During Phase 2 (4 days) education and screening were offered via text messages. Non-financial incentives were offered during Phase 1 and a $10 cash incentive was offered during Phase 2. Rates of specimens provided by students and the direct costs incurred during each phase were compared. RESULTS: 2786 students attended the 31 activities conducted in Phase 1. Of these, 627 students (22.5%) provided urine specimens for chlamydia testing. During Phase 2, the dissemination of 866 text messages resulted in urine specimens from 392 students (45.3%). Costs per test were AUD $175.11 in Phase 1 and AUD $27.13 in Phase 2. CONCLUSIONS: Compared with more labour intensive (and therefore more expensive) screening activities conducted over a 6-month period, offering a small financial incentive to tertiary students through text messaging over a 4-day period significantly increased participation in on-campus chlamydia screening. This model could readily be applied to other populations to increase participation in chlamydia screening.

[18F]-Fluorodeoxyglucose-positron emission tomography for the assessment of histopathologic response and prognosis after completion of neoadjuvant chemoradiation in esophageal cancer.

OBJECTIVE: To evaluate the potential of [(18)F]-fluorodeoxyglucose-positron emission tomography (FDG-PET) after the completion of neoadjuvant chemoradiation for the assessment of histopathologic response and prognosis in the multimodality treatment of patients with esophageal cancer. BACKGROUND: Combined chemoradiation with and without surgery are widely accepted treatment options for patients with locally advanced esophageal cancer. Evidence suggests that patients with response to chemoradiation have no additional benefit from surgery compared with definitive chemoradiation. However, there is still a great lack in noninvasive markers for response assessment in patients with esophageal cancer undergoing multimodality treatment. Interestingly, recent studies imply that FDG-PET significantly correlates with histopathologic response and survival in patients with esophageal cancer undergoing neoadjuvant chemotherapy followed by surgical resection. METHODS: Study patients were recruited from a prospective clinical observation trial on neoadjuvant chemoradiation for esophageal cancer between 1997 and 2006. The study included 119 (98 men, 21 women; median age, 59.4 years; squamous cell cancer: 66; adenocarcinoma: 53) patients with locally advanced esophageal cancer (cT2- 4, N(x), M(0)). All patients received neoadjuvant chemoradiation (cisplatin, 5-FU, 36 Gy) and subsequently underwent transthoracic en bloc esophagectomy. Histomorphologic regression was defined as major histopathologic response when resected specimens contained less than 10% vital residual tumor cells (major response: 47 patients [39.5%]; minor response: 72 patients [60.5%]). FDG-PET was performed before and 2 to 3 weeks after the end of chemoradiation with assessment of the intratumoral FDG-uptake (pretreatment standardized uptake value; post-treatment standardized uptake value; percentage change). These variables were correlated with histopathologic response and survival. RESULTS: Major histomorphologic response was confirmed as an important prognostic factor (P = 0.005; log-rank test). Neoadjuvant chemoradiation led to a significant reduction of intratumoral FDG-uptake (P = 0.0001). A nonsignificant association was seen between major responders and FDG-PET results (P = 0.056). However, the receiver operating characteristic analysis could not identify a standardized uptake value threshold with a relevant predictive value for histomorphologic response. No significant association between metabolic imaging and prognosis was found. CONCLUSION: FDG-PET seems not to be an imaging system that effectively characterizes the groups of major and minor response as well as survival in patients with esophageal cancer after multimodality treatment.

Mean and maximum standardized uptake values in [18F]FDG-PET for assessment of histopathological response in oesophageal squamous cell carcinoma or adenocarcinoma after radiochemotherapy.

PURPOSE: To evaluate the potential of [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) for the assessment of histopathological response and survival after neoadjuvant radiochemotherapy in patients with oesophageal cancer. PATIENTS AND METHODS: In 2005 and 2006, 55 patients (43 men, 12 women; median age 60 years) with locally advanced oesophageal cancer (cT3-4 Nx M0; 24 with squamous cell carcinoma, 31 with adenocarcinoma) underwent transthoracic en bloc oesophagectomy after completion of treatment with cisplatin, 5-fluorouracil, and radiotherapy ad 36 Gy in a prospective clinical trial. Of the 55 patients, 21 (38%) were classified as histopathological responders (<10% vital residual tumour cells) and 34 (62%) as nonresponders. FDG-PET was performed before (PET 1) and 3-4 weeks after the end (PET 2) of radiochemotherapy with assessment of maximum and average standardized uptake values (SUV) for correlation with histopathological response and survival. RESULTS: Histopathological responders had a slightly higher baseline SUV than nonresponders (p<0.0001 between PET 1 and PET 2 for responders and nonresponders) and the decrease was more prominent in responders. Except for SUVmax in patients with squamous cell carcinoma neither baseline nor preoperative SUV nor percent SUV reduction correlated significantly with histopathological response. Histopathological responders had a 2-year overall survival of 91 +/- 9% and nonresponders a survival of 53 +/- 10% (p = 0.007). CONCLUSION: Our study does not support recent reports that FDG-PET predicts histopathological response and survival in patients with locally advanced oesophageal cancer treated by neoadjuvant radiochemotherapy.

Safety first: Recognizing and managing the risks to child participants in magnetic resonance imaging research.

Specialized and up-to-date knowledge is required to identify and manage the risks associated with advanced biomedical research. Additional complexities need to be considered when the research involves infants or young children. In this article, we focus on recent information about the physical risks of pediatric magnetic resonance imaging research and highlight information gaps. With an eye to assisting institutional review boards and researchers, we consider strategies for the management of these risks and formulate key questions aimed at exposing hidden hazards. Institutional review boards should ask these questions, and researchers should bear them in mind as they develop research protocols.

Towards risk factor assessment in inflammatory dilated cardiomyopathy: the SFB/TR 19 study.

BACKGROUND: Patients with idiopathic dilated cardiomyopathy (DCMid) account for about one-third of patients with heart failure. Recent studies found a myocardial viral genomic persistence in up to 67% of DCMid patients, indicating a possible inflammatory etiology (DCMi). Considering the importance of DCMi, we aimed to study the present knowledge on risk factors in DCMi. METHODS: Review of published literature on risk factors for DCMi/DCMid from 1989 through 2005 in Medline database and the Cochrane library (search terms 'epidemiology', 'risk factors', 'inflammatory dilated cardiomyopathy' and 'idiopathic dilated cardiomyopathy'). RESULTS: An extended array of risk factors in DCMid has been investigated in 11 studies. No studies addressing specifically DCMi, however, were found. Consistent associations with DCMid were reported only for diabetes mellitus, black race, male sex and estimated low income. Inconsistent results were observed for the presence of asthma, hypertension and smoking. Few studies addressed potential risk factors such as low education level, infectious diseases and environmental factors. CONCLUSIONS: Considering the high number of potential DCMi patients among patients with DCMid, results on risk factors for DCMid are likely relevant to at least a number of patients with DCMi. Future studies of risk factors in DCMi should include specific case classification and the application of standardized instruments for risk-factor assessment. The four-center SFB/TR 19 study aims to establish a prospective cohort of DCMi patients validated by endomyocardial biopsy.

Entropic wetting and the free isotropic-nematic interface of hard colloidal platelets.

We study bulk and interfacial properties of a model suspension of hard colloidal platelets with continuous orientations and vanishing thickness using both density functional theory, based on either a second virial approach or fundamental measure theory (FMT), and Monte Carlo (MC) simulations. We calculate the bulk equation of state, bulk isotropic-nematic (IN) coexistence, and properties of the (planar) free IN interface and of adsorption at a planar hard wall, where we find complete wetting of the nematic phase at the isotropic-wall interface upon approaching bulk IN coexistence. We investigate in detail the asymptotic decay of correlations at large distances. In all cases, the results from FMT and MC agree quantitatively. Our findings are of direct relevance to understanding interfacial properties of dispersions of colloidal platelets.