Mechanical failure of the intramedullary hip screw in a subtrochanteric femoral fracture

The Gamma nail, an implant specifically designed for intertrochanteric and subtrochanteric femoral fractures, has been criticized for its high risk of secondary shaft fractures. A modified design, the intramedullary hip screw has recently been introduced to correct this complication. We present a case of mechanical failure of this new implant that occurred in a pathological subtrochanteric fracture. The centering sleeve of the implant became loose and migrated while the head screw penetrated the acetabulum. Refixation was successful.     

Formation of oxidising species and their role in the viscosity loss of cereal beta-glucan extracts

The aim of this study was to determine the role of the formation of radicals and hydrogen peroxide in the viscosity loss of beta-glucan extracts from oat and barley. Radicals derived from endogenous H₂O₂ were formed spontaneously in all extracts. The decomposition of H₂O₂ by catalase had little or no effect on the viscosity, and the radical formation detected and measured by electron spin resonance (ESR) spectroscopy did not predict the shelf life of crude beta-glucan extracts. The addition of FeSO₄ accelerated the radical formation and viscosity loss, revealing the sensitivity of the extract viscosity towards catalysts for oxidation. Using 50% cadoxen in the extracts slowed down the viscosity loss in all extracts but still led to a 10–70% decrease of the initial viscosities during 4 weeks of storage. The results suggest that the viscosity loss may be a result from multiple mechanisms including chemical reactions during storage as well as aggregation and conformational changes.     

How to construct small probabilistic roadmaps with a good coverage?

We investigate how we can construct small probabilistic roadmaps in a reasonable time while still keeping a good coverage and connectivity. We propose a new neighborhood-based method that can reduce the size of the roadmaps by filtering out unnecessary nodes. We then experimentally test it against a basic probabilistic roadmap planner and a visibility-based planner. We use both a uniform sampling and a bridge test sampling in our tests. The results show that the neighborhood-based method can reduce the number of nodes considerably. The neighborhood-based method is simple to implement, it works well with a uniform sampling, and it does not need any additional parameters when compared with the basic planner.     

Endometrial cancer cell lines are sensitive to paclitaxel

We have previously reported a 24 fold difference in the cisplatin sensitivity and a 12 fold difference in carboplatin sensitivity of endometrial carcinoma cell lines. In this study as evaluate paclitaxel sensitivity of the same cell lines. We tested nine endometrial cancer cell lines with the 96-well plate clonogenic assay using limiting dilution. The chemosensitivity was expressed as IC50 value, the drug concentration causing 50% inhibition of clonogenic survival. IC50 values were obtained from dose-response curves after fitting the data to the linear quadratic equation. The IC50 values for paclitaxel were 0.49 - 2.3 nM showing only a 4.7 fold difference between various cell lines. No correlation could be demonstrated between in vitro paclitaxel and platinum analog sensitivities of endometrial adenocarcinoma cell lines. The variance in paclitaxel sensitivity of different cell lines was little. Our results suggest that endometrial adenocarcinoma cell lines tested with the same methods. The clinical efficacy of paclitaxel in the treatment of endometrial cancer should further be evaluated in clinical trials.     

Visualization of a pharmaceutical unit operation: wet granulation

Recent developments in the field of process engineering and manufacturing sciences enable a new level of process understanding. However, extracting this understanding from increasing amounts of information is challenging. The aim of this study was to create a process vector from a model process describing all relevant information and, by that means, create a tool for combining and visualizing this information. Physical (impeller torque and temperature) and chemical (near-infrared spectroscopy) information from a small-scale high-shear granulation was used in the process vector. The vectors created were visualized by two different methods: principal component analysis (PCA) and the self-organizing map (SOM). None of the individual measurement techniques were able to describe the state of the process alone, although they provided important information about the process. By combining the data and visualizing it, an overview could be achieved. The SOM approach had two advantages over the PCA: it presented the results in terms of the original variables and enabled the analysis of nonlinear responses. However, both visualization methods could be used to describe the progress of the process and to increase the level of process understanding.     

Binary monolayers of single-stranded oligonucleotides and blocking agent for hybridisation

The hybridisation of thiol-modified single-stranded DNA (SH-ssDNA) embedded in lipoate or hydrophilic polymer monolayers on gold have been studied through the technique of surface plasmon resonance (SPR). SH-ssDNA and the blocking agents were co-adsorbed on gold from the same solution or the surface was post-treated with the blocking agents. The assembling process is allowed to take place for only 10 min. Binding of non-complementary and complementary DNA is dependent both on the blocking agent and on the assembling method used. The lowest non-complementary binding and the highest complementary binding of DNA was obtained with a layer assembled from a binary solution of SH-ssDNA and the lipoate blocking agent.     

Molecular approaches to study probiotic bacteria

Functional foods comprising probiotic bacteria are receiving increasing attention from the scientific community and science funding agencies [1]. An essential aspect relating to the functionality of probiotic-based foods is to develop molecular methods to determine the presence, activity and viability of probiotic bacteria in the human gastrointestinal (GI) tract [2]. The GI tract is composed of a complex ecosystem of various microbial habitats colonized by numerous different commensal micro-organisms. This indigenous gut microbiota is essential to the overall health of the host by performing important physiological functions. In particular, they protect against pathogenic bacteria and drive the development of the immune system during neonatal life. Further metabolic activities of the GI microbiota that beneficially affect the host include continued degradation of food components, vitamin production, and production of short chain fatty acids that feed the colonic mucosa. It is clear that factors such as diet, sickness, stress, or medication can result in loss of well-being of the host, and it is assumed that some of these symptoms are due to perturbation of what is termed the normal balance of the gut microbiota. Knowledge of the structure and function of the standard microbiota, and its response to diet, genetic background and lifetime of the host must be taken into account when designing probiotic-based functional foods. The application of molecular techniques for detection and identification of microbes has provided a major breakthrough in the analysis of microbial ecosystems and their function [3]. The successful application and further potential of these molecular methods to study probiotic bacteria and their impact on the standard GI microbiota is discussed below.     

Investigation of the phase separation of PNIPAM using infrared spectroscopy together with multivariate data analysis

The use of vibrational spectroscopy to investigate complex structural changes in polymers yields chemically rich data, but interpretation can be challenging and subtle but meaningful spectral changes may be missed through visual inspection alone. Multivariate analysis is an efficient approach to gain an oversight of small but systematic spectral differences anywhere within the spectra, providing further insight into structural changes and associated transformation mechanisms. In this study, the novel analytical approach of infrared spectroscopy combined with principal component analysis and Gaussian peak fitting was used to investigate the structural changes in aqueous solutions of a polymer, using poly(N-isopropyl acrylamide) (PNIPAM) in the atactic form and with controlled tacticity as a model system. Subtle spectral changes associated with the dehydration and phase separation upon heating included peak shifts, an area ratio change of the amide I band to the amide II band and formation of a new peak in the amide I band were efficiently detected. Dehydration and phase separation of PNIPAM occurred in two temperature ranges, one for the atactic and one for isotactic rich part, both involving a complex re-organization of the hydrogen bonds and change of the hydration layer. The changes agreed with existing results from other techniques, and new insights were gained into the effect of controlled tacticity on phase transformation behaviour. The study demonstrates that infrared spectroscopy combined with the multivariate analytical method principal component analysis and Gaussian peak fitting is an efficient approach to probing structural change in polymers during heating. The simplicity of the presented approach could find excellent use in analysing and understanding the molecular environment of a range of stimuli-responsive polymers, for instance block or grafted types of polymers, as well as those with controlled tacticity.     

600 MHz direct modulation of short external cavity wavelength-tunable diode laser

The current modulation characteristics of a short external cavity tunable laser are presented. The 1540 nm Fabry-Perot diode laser is wavelength-tuned by the electrostatically controlled silicon micromachined Fabry-Perot interferometer device. The measured -3 dB cutoff frequency of 600 MHz is the widest reported direct modulation bandwidth of the external cavity tunable laser.