Wavelet Methods and Inverse Problems

Archaeological investigations are designed to acquire information without damaging the archaeological site. Magnetometry is one of the important techniques for producing a surface grid of readings, which can be used to infer underground features. The inversion of this data, to give a fitted model, is an inverse problem. This type of problem can be ill-posed or ill-conditioned, making the estimation of model parameters less stable or even impossible. More precisely, the relationship between archaeological data and parameters is expressed by a likelihood. It is not possible to use the standard regression estimate obtained through the likelihood, which means that no maximum likelihood estimate exists. Instead, various constraints can be added through a prior distribution with an estimate produced using the posterior distribution. Current approaches incorporate prior information describing smoothness, which is not always appropriate. The biggest challenge is that the reconstruction of an archaeological site as a single layer requires various physical features such as depth and extent to be assumed. By applying a smoothing prior in the analysis of stratigraphy data, however, these features are not easily estimated. Wavelet analysis has proved to be highly efficient at eliciting information from noisy data. Additionally, complicated signals can be explained by interpreting only a small number of wavelet coefficients. It is possible that a modelling approach, which attempts to describe an underlying function in terms of a multi-level wavelet representation will be an improvement on standard techniques. Further, a new method proposed uses an elastic-net based distribution as the prior. Two methods are used to solve the problem, one is based on one-stage estimation and the other is based on two stages. The one-stage considers two approaches a single prior for all wavelet resolution levels and a level-dependent prior, with separate priors at each resolution level. In a simulation study and a real data analysis, all these techniques are compared to several existing methods. It is shown that the methodology using a single prior provides good reconstruction, comparable even to several established wavelet methods that use mixture priors

Cognitive based neural prosthetics

Intense activity in neural prosthetic research has recently demonstrated the possibility of robotic interfaces that respond directly to the nervous system. The question remains of how the flow of information between the patient and the prosthetic device should be designed to provide a safe, effective system that maximizes the patient’s access to the outside world. Much recent work by other investigators has focused on using decoded neural signals as low-level commands to directly control the trajectory of screen cursors or robotic end-effectors. Here we review results that show that high-level, or cognitive, signals can be decoded from planned arm movements. These results, coupled with fundamental limitations in signal recording technology, motivate an approach in which cognitive neural signals play a larger role in the neural interface. This proposed paradigm predicates that neural signals should be used to instruct external devices, rather than control their detailed movement. This approach will reduce the effort required of the patient and will take advantage of established and on-going robotics research in intelligent systems and human-robot interfaces

Recording advances for neural prosthetics

An important challenge for neural prosthetics research is to record from populations of neurons over long periods of time, ideally for the lifetime of the patient. Two new advances toward this goal are described, the use of local field potentials (LFPs) and autonomously positioned recording electrodes. LFPs are the composite extracellular potential field from several hundreds of neurons around the electrode tip. LFP recordings can be maintained for longer periods of time than single cell recordings. We find that similar information can be decoded from LFP and spike recordings, with better performance for state decodes with LFPs and, depending on the area, equivalent or slightly less than equivalent performance for signaling the direction of planned movements. Movable electrodes in microdrives can be adjusted in the tissue to optimize recordings, but their movements must be automated to be a practical benefit to patients. We have developed automation algorithms and a meso-scale autonomous electrode testbed, and demonstrated that this system can autonomously isolate and maintain the recorded signal quality of single cells in the cortex of awake, behaving monkeys. These two advances show promise for developing very long term recording for neural prosthetic applications

Low-Power Circuits for Brain–Machine Interfaces

This paper presents work on ultra-low-power circuits for brain–machine interfaces with applications for paralysis prosthetics, stroke, Parkinson’s disease, epilepsy, prosthetics for the blind, and experimental neuroscience systems. The circuits include a micropower neural amplifier with adaptive power biasing for use in multi-electrode arrays; an analog linear decoding and learning architecture for data compression; low-power radio-frequency (RF) impedance-modulation circuits for data telemetry that minimize power consumption of implanted systems in the body; a wireless link for efficient power transfer; mixed-signal system integration for efficiency, robustness, and programmability; and circuits for wireless stimulation of neurons with power-conserving sleep modes and awake modes. Experimental results from chips that have stimulated and recorded from neurons in the zebra finch brain and results from RF power-link, RF data-link, electrode- recording and electrode-stimulating systems are presented. Simulations of analog learning circuits that have successfully decoded prerecorded neural signals from a monkey brain are also presented

Cognitive Control Signals for Neural Prosthetics

Recent development of neural prosthetics for assisting paralyzed patients has focused on decoding intended hand trajectories from motor cortical neurons and using this signal to control external devices. In this study, higher level signals related to the goals of movements were decoded from three monkeys and used to position cursors on a computer screen without the animals emitting any behavior. Their performance in this task improved over a period of weeks. Expected value signals related to fluid preference, the expected magnitude, or probability of reward were decoded simultaneously with the intended goal. For neural prosthetic applications, the goal signals can be used to operate computers, robots, and vehicles, whereas the expected value signals can be used to continuously monitor a paralyzed patient's preferences and motivation

Randomised single centre double-blind placebo controlled phase II trial of Tocovid SupraBio in combination with pentoxifylline in patients suffering long-term gastrointestinal adverse effects of radiotherapy for pelvic cancer: The PPALM study.

BACKGROUND: Preclinical data suggest that combined gamma-tocotrienol with pentoxifylline ameliorates radiotherapy-induced gastrointestinal damage. AIM: To test whether gastrointestinal symptoms arising after radiotherapy, and persisting after maximal medical therapy, can be improved using Tocovid SupraBio 200 mg and pentoxifylline 400 mg orally twice daily for one year. Patients stratified by severity of symptoms, and randomised to active treatment or matched placebo were assessed after 12 months. The primary end point was improvement in gastrointestinal symptoms measured using the Inflammatory Bowel Disease Questionnaire, bowel subset score. Changes in bio-markers of fibrosis were assessed. RESULTS: 62 patients, median age 66, 34(55%) treated for prostate, 21(34%) gynaecological, 6(10%) anal and one(1%) rectal cancer were recruited; 40(65%) randomised to treatment, 22(35%) to placebo, 39 months (median) after radiotherapy completion. Gamma tocotrienol was not detected in serum in 41% of treated patients, despite good compliance with study medication. Treatment was completed in 28(70%) and 17(77%) patients in the treatment and placebo groups respectively. No improvement in symptom scores nor in quality of life was identified. Thirteen serious adverse events occurred. A transient ischaemic attack, was possibly related to pentoxifylline, others were assessed as unlikely to be related to treatment. Levels of EGF, PDGF and FGF were significantly reduced and consistent trends in reduced inflammation were seen during treatment but were not sustained once treatment ended. SUMMARY: This single centre study closed prematurely and therefore data interpretation is of necessity limited. No clinical benefit was demonstrated. However, biochemical data suggest that this intervention does have anti-inflammatory and anti-fibrotic effects

Intratumoral Hydrogen Peroxide With Radiation Therapy in Locally Advanced Breast Cancer: Results From a Phase 1 Clinical Trial.

Purpose Hydrogen peroxide (H2O2) plays a vital role in normal cellular processes but at supraphysiological concentrations causes oxidative stress and cytotoxicity, a property that is potentially exploitable for the treatment of cancer in combination with radiation therapy (RT). We report the first phase 1 trial testing the safety and tolerability of intratumoral H2O2 + external beam RT as a novel combination in patients with breast cancer and exploratory plasma marker analyses investigating possible mechanisms of action.Methods and materials Twelve patients with breast tumors ≥3 cm (surgically or medically inoperable) received intratumoral H2O2 with either 36 Gy in 6 twice-weekly fractions (n = 6) or 49.5 Gy in 18 daily fractions (n = 6) to the whole breast ± locoregional lymph nodes in a single-center, nonrandomized study. H2O2 was mixed in 1% sodium hyaluronate gel (final H2O2 concentration 0.5%) before administration to slow drug release and minimize local discomfort. The mixture was injected intratumorally under ultrasound guidance twice weekly 1 hour before RT. The primary endpoint was patient-reported maximum intratumoral pain intensity before and 24 hours postinjection. Secondary endpoints included grade ≥3 skin toxicity and tumor response by ultrasound. Blood samples were collected before, during, and at the end of treatment for cell-death and immune marker analysis.Results Compliance with H2O2 and RT was 100%. Five of 12 patients reported moderate pain after injection (grade 2 Common Terminology Criteria for Adverse Events v4.02) with median duration 60 minutes (interquartile range, 20-120 minutes). Skin toxicity was comparable to RT alone, with maintained partial/complete tumor response relative to baseline in 11 of 12 patients at last follow-up (median 12 months). Blood marker analysis highlighted significant associations of TRAIL, IL-1β, IL-4, and MIP-1α with tumor response.Conclusions Intratumoral H2O2 with RT is well tolerated with no additional toxicity compared with RT alone. If efficacy is confirmed in a randomized phase 2 trial, the approach has potential as a cost-effective radiation response enhancer in multiple cancer types in which locoregional control after RT alone remains poor

Motor Preparatory Activity in Posterior Parietal Cortex is Modulated by Subjective Absolute Value

For optimal response selection, the consequences associated with behavioral success or failure must be appraised. To determine how monetary consequences influence the neural representations of motor preparation, human brain activity was scanned with fMRI while subjects performed a complex spatial visuomotor task. At the beginning of each trial, reward context cues indicated the potential gain and loss imposed for correct or incorrect trial completion. FMRI-activity in canonical reward structures reflected the expected value related to the context. In contrast, motor preparatory activity in posterior parietal and premotor cortex peaked in high “absolute value” (high gain or loss) conditions: being highest for large gains in subjects who believed they performed well while being highest for large losses in those who believed they performed poorly. These results suggest that the neural activity preceding goal-directed actions incorporates the absolute value of that action, predicated upon subjective, rather than objective, estimates of one's performance

The Palestinian Terrestrial Vertebrate Fauna Preserved at the Biology Exhibitions of the Universities of the Gaza Strip

The Gaza Strip (365 km2 ) of Palestine (27,000 km2 ) is home to a wealth of terrestrial vertebrate fauna. Some of these faunistic species find their ways to preservation at the local universities. Hence, the current study comes to document the Palestinian terrestrial vertebrate fauna acquired by the biology exhibitions (BEs) of Al-Azhar University, Islamic University of Gaza and Al-Aqsa University that are located at the Gaza City of the Gaza Strip. The amphibians, reptiles, birds and mammals preserved at BEs of the universities in question were surveyed and scientifically classified during a three-month period extending from January to March, 2012. The study showed that all BEs of local universities are underdeveloped, lacking attention and suffer from specimen scarcity and good preservation. The BE at Al-Azhar University is the best in the arrangement and preservation of bird specimens. A total number of 200 specimens belonging to 54 terrestrial vertebrate fauna species, 39 families and 17 orders was recorded at BEs. Reptiles constituted 40.7% of the total species recorded, followed by birds (38.9%), mammals (14.8%) and amphibians (5.6%). The Islamic University of Gaza was considered the best in terms of the number of preserved species (39.8%), followed by Al-Azhar University (36.3%) and Al-Aqsa University (23.9%). The Common Toad (Bufo viridis) was the most preserved among the amphibian species recorded. Squamata was the biggest reptilian order, comprising 20 species (8 lizards and 12 snakes), with the Syrian Black Snake (Coluber jugularis asianus) was the commonest. The Palestine Viper (Vipera palaestinae) is endemic to Palestine and most venomous and dangerous to human health. The Great White Pelican (Pelecanus onocrotalus) was the largest Palestinian bird preserved at BE of Al-Azhar University. The Egyptian Mongoose (Herpestes ichneumon) and the Common Badger (Meles meles) were the biggest mammalian specimens preserved, while the Palestine Mole-rat (Spalax leucodon ehrenbergi) was the only Palestine endemic species encountered among the preserved mammals. Finally, the improvement of BEs of local universities and the construction of a Central Museum of Natural History is highly recommended in order to change the Palestinians’ attitudes toward a sustainable ecological conservation in the Gaza Strip