Using ordinal logistic regression to evaluate the performance of laser-Doppler predictions of burn-healing time

Background Laser-Doppler imaging (LDI) of cutaneous blood flow is beginning to be used by burn surgeons to predict the healing time of burn wounds; predicted healing time is used to determine wound treatment as either dressings or surgery. In this paper, we do a statistical analysis of the performance of the technique. Methods We used data from a study carried out by five burn centers: LDI was done once between days 2 to 5 post burn, and healing was assessed at both 14 days and 21 days post burn. Random-effects ordinal logistic regression and other models such as the continuation ratio model were used to model healing-time as a function of the LDI data, and of demographic and wound history variables. Statistical methods were also used to study the false-color palette, which enables the laser-Doppler imager to be used by clinicians as a decision-support tool. Results Overall performance is that diagnoses are over 90% correct. Related questions addressed were what was the best blood flow summary statistic and whether, given the blood flow measurements, demographic and observational variables had any additional predictive power (age, sex, race, % total body surface area burned (%TBSA), site and cause of burn, day of LDI scan, burn center). It was found that mean laser-Doppler flux over a wound area was the best statistic, and that, given the same mean flux, women recover slightly more slowly than men. Further, the likely degradation in predictive performance on moving to a patient group with larger %TBSA than those in the data sample was studied, and shown to be small. Conclusion Modeling healing time is a complex statistical problem, with random effects due to multiple burn areas per individual, and censoring caused by patients missing hospital visits and undergoing surgery. This analysis applies state-of-the art statistical methods such as the bootstrap and permutation tests to a medical problem of topical interest. New medical findings are that age and %TBSA are not important predictors of healing time when the LDI results are known, whereas gender does influence recovery time, even when blood flow is controlled for. The conclusion regarding the palette is that an optimum three-color palette can be chosen 'automatically', but the optimum choice of a 5-color palette cannot be made solely by optimizing the percentage of correct diagnoses

Meniscal ossicle

Meniscal ossicle, or bone within the substance of meniscus, is a rare entity and commonly confused with a loose body both clinically and radiologically. MRI is the modality that can definitely diagnose meniscal ossicle and avoid unnecessary diagnostic arthroscopy. Here we report one such case diagnosed using MRI; this patient is doing well without surgery one year after diagnosis

Comparative analysis of long-haul system based on SSB modulation utilising dual parallel Mach–Zehnder modulators

In this paper, we have proposed a long-haul optical transmission system, based on a single sideband (SSB) modulation scheme. Analytical and simulation models have been developed, optimised and demonstrated for the proposed SSB system configurations. The SSB modulation scheme was proposed to overcome dispersion in the fibre. We have shown that the related link losses can be minimized by increasing the quality of the optical signal at the modulation. We have optimised the radio over fibre configuration scheme based on dual parallel dual drive Mach–Zehnder Modulator, thereby increasing transmission length of the fibre. With the proposed SSB, by suppressing some of the harmonics and cancelling one of the sidebands, we have halved the RF power fading and interference. The developed analytical (theoretical/mathematical) model agrees very well with the simulation results using two (both) different commercial simulation tools. The optical signal is boosted while minimizing the number of repeaters. We report a SSB configuration, compensation and amplification with individual spans of 150 km, by extending the length of the link up to 3250 km. The proposed system configuration exhibits high performance with less complexity and lower cost

Endogenous sex hormones and prostate cancer: a quantitative review of prospective studies

This paper presents a quantitative review of the data from eight prospective epidemiological studies, comparing mean serum concentrations of sex hormones in men who subsequently developed prostate cancer with those in men who remained cancer free. The hormones reviewed have been postulated to be involved in the aetiology of prostate cancer: androgens and their metabolites testosterone (T), non-SHBG-bound testosterone (non-SHBG-bound T), di-hydrotestosterone (DHT), androstanediol glucuronide (A-diol-g), androstenedione (A-dione), dehydroepiandrosterone sulphate (DHEAS), sex hormone binding globulin (SHBG), the oestrogens, oestrone and oestradiol, luteinizing hormone (LH) and prolactin. The ratio of the mean hormone concentration in prostate cancer cases to that of controls (and its 95% confidence interval (CI)) was calculated for each study, and the results summarized by calculating the weighted average of the log ratios. No differences in the average concentrations of the hormones were found between prostate cancer cases and controls, with the possible exception of A-diol-g which exhibited a 5% higher mean serum concentration among cases relative to controls (ratio 1.05, 95% CI 1.00-1.11), based on 644 cases and 1048 controls. These data suggest that there are no large differences in circulating hormones between men who subsequently go on to develop prostate cancer and those who remain free of the disease. Further research is needed to substantiate the small difference found in A-diol-g concentrations between prostate cancer cases and controls

MAS NMR investigation of molecular order in an ionic liquid crystal

The structure and molecular order in the thermotropic ionic liquid crystal (ILC), [choline][geranate(H)octanoate], an analogue of Choline And GEranate (CAGE), which has potential for use as a broad-spectrum antimicrobial and transdermal and oral delivery agent, were investigated by magic-angle spinning (MAS) nuclear magnetic resonance (NMR), polarizing optical microscopy, small-angle X-ray scattering (SAXS), and mass spectrometry. Mass spectrometry and the 1H NMR chemical shift reveal that CAGE-oct is a dynamic system, with metathesis (the exchange of interacting ions) and hydrogen exchange occurring between hydrogen-bonded/ionic complexes such as [(choline)(geranate)(H)(octanoate)], [(choline)(octanoate)2(H)], and [(choline)(geranate)2(H)]. These clusters, which are shown by mass spectrometry to be significantly more stable than expected for typical electrostatic ion clusters, involve hydrogen bonding between the carboxylic acid, carboxylate, and hydroxyl groups, with rapid hydrogen bond breaking and re-formation observed to average the 1H chemical shifts. The formation of a partial bilayer liquid crystal (LC) phase was identified by SAXS and polarizing optical microscopy at temperatures below ∼293 K. The occurrence of this transition close to room temperature could be utilized as a potential temperature-induced “switch” of the anisotropic properties for particular applications. The presence of an isotropic component of approximately 23% was observed to coexist with the LC phase, as detected by polarizing optical microscopy and quantified by both 1H–13C dipolar-chemical shift correlation (DIPSHIFT) and 1H double-quantum (DQ) MAS NMR experiments. At temperatures above the LC-to-isotropic transition, intermediate-range order (clustering of polar and nonpolar domains), a feature of many ILs, persists. Site-specific order parameters for the LC phase of CAGE-oct were obtained from the MAS NMR measurement of the partially averaged 13C–1H dipolar couplings (DCH) by cross-polarization (CP) build-up curves and DIPSHIFT experiments, and 1H–1H dipolar couplings (DHH) by double-quantum (DQ) build-up curves. The corresponding order parameters, SCH and SHH, are in the range 0–0.2 and are lower compared to those for smectic (i.e., layered) phases of conventional nonionic liquid crystals, resembling those of lamellar phases formed by lyotropic surfactant–solvent systems

Comb-Based Radio-Frequency Photonic Filters with Rapid Tunability and High Selectivity

Photonic technologies have received considerable attention for enhancement of radio-frequency (RF) electrical systems, including high-frequency analog signal transmission, control of phased arrays, analog-to-digital conversion, and signal processing. Although the potential of radio-frequency photonics for implementation of tunable electrical filters over broad RF bandwidths has been much discussed, realization of programmable filters with highly selective filter lineshapes and rapid reconfigurability has faced significant challenges. A new approach for RF photonic filters based on frequency combs offers a potential route to simultaneous high stopband attenuation, fast tunability, and bandwidth reconfiguration. In one configuration tuning of the RF passband frequency is demonstrated with unprecedented (~40 ns) speed by controlling the optical delay between combs. In a second, fixed filter configuration, cascaded four-wave mixing simultaneously broadens and smoothes comb spectra, resulting in Gaussian RF filter lineshapes exhibiting extremely high (>60 dB) main lobe to sidelobe suppression ratio and (>70 dB) stopband attenuation.Comment: Updated the submission with the most recent version of the pape

Molecular signatures for CCN1, p21 and p27 in progressive mantle cell lymphoma

Mantle cell lymphoma (MCL) is a comparatively rare non-Hodgkin’s lymphoma characterised by overexpression of cyclin D1.Many patients present with or progress to advanced stage disease within 3 years. MCL is considered an incurable disease withmedian survival between 3 and 4 years. We have investigated the role(s) of CCN1 (CYR61) and cell cycle regulators inprogressive MCL. We have used the human MCL cell lines REC1 G519 > JVM2 cells by RQ-PCR, depicting a decrease in CCN1expression with disease progression. Investigation of CCN1 isoform expression by western blotting showed that whilst expres-sion of full-length CCN1 was barely altered in the cell lines, expression of truncated forms (18–20 and 28–30 kDa) decreasedwith disease progression. We have then demonstrated that cyclin D1 and cyclin dependent kinase inhibitors (p21CIP1and p27KIP1)are also involved in disease progression. Cyclin D1 was highly expressed in REC1 cells (OD: 1.0), reduced to one fifth in G519cells (OD: 0.2) and not detected by western blotting in JVM2 cells. p27KIP1followed a similar profile of expression as cyclin D1.Conversely, p21CIP1was absent in the REC1 cells and showed increasing expression in G519 and JVM2 cells. Subcellularlocalization detected p21CIP1/p27KIP1primarily within the cytoplasm and absent from the nucleus, consistent with altered roles in treatment resistance. Dysregulation of the CCN1 truncated forms are associated with MCL progression. In conjunction withreduced expression of cyclin D1 and increased expression of p21, this molecular signature may depict aggressive disease andtreatment resistance