On the uniqueness of the surface sources of evoked potentials

The uniqueness of a surface density of sources localized inside a spatial region $R$ and producing a given electric potential distribution in its boundary $B_0$ is revisited. The situation in which $R$ is filled with various metallic subregions, each one having a definite constant value for the electric conductivity is considered. It is argued that the knowledge of the potential in all $B_0$ fully determines the surface density of sources over a wide class of surfaces supporting them. The class can be defined as a union of an arbitrary but finite number of open or closed surfaces. The only restriction upon them is that no one of the closed surfaces contains inside it another (nesting) of the closed or open surfaces.Comment: 16 pages, 5 figure

Comparative analysis of Salmonella susceptibility and tolerance to the biocide chlorhexidine identifies a complex cellular defense network

peer-reviewedChlorhexidine is one of the most widely used biocides in health and agricultural settings as well as in the modern food industry. It is a cationic biocide of the biguanide class. Details of its mechanism of action are largely unknown. The frequent use of chlorhexidine has been questioned recently, amidst concerns that an overuse of this compound may select for bacteria displaying an altered susceptibility to antimicrobials, including clinically important anti-bacterial agents. We generated a Salmonella enterica serovar Typhimurium isolate (ST24CHX) that exhibited a high-level tolerant phenotype to chlorhexidine, following several rounds of in vitro selection, using sub-lethal concentrations of the biocide. This mutant showed altered suceptibility to a panel of clinically important antimicrobial compounds. Here we describe a genomic, transcriptomic, proteomic, and phenotypic analysis of the chlorhexidine tolerant S. Typhimurium compared with its isogenic sensitive progenitor. Results from this study describe a chlorhexidine defense network that functions in both the reference chlorhexidine sensitive isolate and the tolerant mutant. The defense network involved multiple cell targets including those associated with the synthesis and modification of the cell wall, the SOS response, virulence, and a shift in cellular metabolism toward anoxic pathways, some of which were regulated by CreB and Fur. In addition, results indicated that chlorhexidine tolerance was associated with more extensive modifications of the same cellular processes involved in this proposed network, as well as a divergent defense response involving the up-regulation of additional targets such as the flagellar apparatus and an altered cellular phosphate metabolism. These data show that sub-lethal concentrations of chlorhexidine induce distinct changes in exposed Salmonella, and our findings provide insights into the mechanisms of action and tolerance to this biocidal agent.Department of Agriculture, Food and the Marin

Multi-source localization in MEG using simulated annealing: model order determination and parameter accuracy

Empirical neuromagnetic studies have reported that multiple brain regions are active at single instants in time as well as across time intervals of interest. Determining the number of active regions, however, required a systematic search across increasing model orders using reduced chi-square measure of goodness-of-fit and multiple starting points within each model order assumed. Simulated annealing was recently proposed for noiseless biomagnetic data as an effective global minimizer. A modified cost function was also proposed to effectively deal with an unknown number of dipoles for noiseless, multi-source biomagnetic data. Numerical simulation studies were conducted using simulated annealing to examine effects of a systematic increase in model order using both reduced chi-square as a cost function as well as a modified cost function, and effects of overmodeling on parameter estimation accuracy. Effects of different choices of weighting factors are also discussed. Simulated annealing was also applied to visually evoked neuromagnetic data and the effectiveness of both cost functions in determining the number of active regions was demonstrated

Forensic investigation of small-scale digital devices: a futuristic view

Small-scale digital devices like smartphones, smart toys, drones, gaming consoles, tablets, and other personal data assistants have now become ingrained constituents in our daily lives. These devices store massive amounts of data related to individual traits of users, their routine operations, medical histories, and financial information. At the same time, with continuously evolving technology, the diversity in operating systems, client storage localities, remote/cloud storages and backups, and encryption practices renders the forensic analysis task multi-faceted. This makes forensic investigators having to deal with an array of novel challenges. This study reviews the forensic frameworks and procedures used in investigating small-scale digital devices. While highlighting the challenges faced by digital forensics, we explore how cutting-edge technologies like Blockchain, Artificial Intelligence, Machine Learning, and Data Science may play a role in remedying concerns. The review aims to accumulate state-of-the-art and identify a futuristic approach for investigating SSDDs

The Abundance of Akkermansia muciniphila and its Relationship with Sulphated Colonic Mucins in Health and Ulcerative Colitis

Akkermansia muciniphila utilises colonic mucin as its substrate. Abundance is reduced in ulcerative colitis (UC), as is the relative proportion of sulphated mucin in the mucus gel layer (MGL). It is unknown if these phenomena are related, however reduced sulphated mucins could contribute to reduced abundance, owing to a lack of substrate. The aim of this study was to quantify A. muciniphila within the MGL and to relate these findings with markers of inflammation and the relative proportion of sulphomucin present. Colonic biopsies and mucus brushings were obtained from 20 patients with active UC (AC), 14 with quiescent UC (QUC) and 20 healthy controls (HC). A. muciniphila abundance was determined by RT-PCR. High iron diamine alcian-blue staining was performed for histological analysis. Patients with AC had reduced abundance of A. muciniphila compared to HC and QUC. A positive association was found between A. muciniphila abundance and higher percentage of sulphated mucin (ρ 0.546, p = 0.000). Lower abundances of A. muciniphila correlated with higher inflammatory scores (ρ = 0.294 (p = 0.001)). This study confirms an inverse relationship between A. muciniphila and inflammation and a positive association between A. muciniphila abundance and percentage of sulfated mucin in the MGL

A randomised trial of an internet weight control resource: The UK Weight Control Trial [ISRCTN58621669]

BACKGROUND: Obesity treatment is notoriously unsuccessful and one of the barriers to successful weight loss reported by patients is a lack of social support. The Internet offers a novel and fast approach to the delivery of health information, enabling 24-hour access to help and advice. However, much of the health information available on the Internet is unregulated or not written by qualified health professionals to provide unbiased information. The proposed study aims to compare a web-based weight loss package with traditional dietary treatment of obesity in participants. The project aims to deliver high quality information to the patient and to evaluate the effectiveness of this information, both in terms of weight loss outcomes and cost-effectiveness. METHODS: This study is a randomised controlled trial of a weight loss package against usual care provided within General Practice (GP) surgeries in Leeds, UK. Participants will be recruited via posters placed in participating practices. A target recruitment figure of 220 will enable 180 people to be recruited (allowing for 22% dropout). Participants agreeing to take part in the study will be randomly allocated using minimisation to either the intervention group, receiving access to the Internet site, or the usual care group. The primary outcome of the study will be the ability of the package to promote change in BMI over 6 and 12 months compared with traditional treatment. Secondary outcomes will be the ability of the Internet package to promote change in reported lifestyle behaviours. Data will be collected on participant preferences, adherence to treatment, health care use and time off work. Difference in cost between groups in provision of the intervention and the cost of the primary outcome will also be estimated. CONCLUSION: A positive result from this study would enhance the repertoire of treatment approaches available for the management of obesity. A negative result would be used to inform the research agenda and contribute to redefining future strategies for tackling obesity

Latency differences and effects of selective attention to gratings in the central and right visual fields: II

The goals were to examine the temporal sequence in which visual information (such as visual field, spatial frequency) are processed and to determine whether different neural sources are activated when such features are attended versus not attended. These issues are basic to current models of visual selective attention. 10 refs., 4 figs

Nanotechnology Solutions for Global Water Challenges

The lack of clean and safe drinking water is responsible for more deaths than war, terrorism and weapons of mass destruction combined. This suggests contaminated water poses a significant threat to human health and welfare. In addition, standard water disinfection approaches such as sedimentation, filtration, and chemical or biological degradation are not fully capable of destroying emerging contaminants (e.g. pesticides, pharmaceutical waste products) or certain types of bacteria (e.g. Cryptosporidium parvum). Nanomaterials and nanotechnology based devices can potentially be employed to solve the challenges posed by various contaminants and microorganisms. Nanomaterials of different shapes, namely nanoparticles, nanotubes, nanowires and fibers have the ability to function as adsorbents and catalysts. These possess an expansive array of physicochemical characteristics deeming them highly attractive for the production of reactive media for water membrane filtration, a vital step in the production of potable water. As a result of their exceptional adsorptive capacity for water contaminants, graphene based nanomaterials have emerged as an area of significant importance in the area of membrane filtration and water treatment. In addition, Advanced Oxidation Processes (AOPs) together with or without sources of light irradiation or ultrasound, have been found to be promising alternatives for water treatment at near ambient temperature and pressure. Furthermore, the uses of visible light active titanium dioxide photocatalysts and photo-Fenton processes have shown significant potential for water purification. A wide variety of nanomaterial based sensors, for the monitoring of water quality, have also been reviewed in detail. In conclusion, the rapid and continued growth in the area of nanomaterial based devices offers significant hope for addressing future water quality challenges