PANDA: a self-driving lab for studying electrodeposited polymer films.

We introduce the polymer analysis and discovery array (PANDA), an automated system for high-throughput electrodeposition and functional characterization of polymer films. The PANDA is a custom, modular, and low-cost system based on a CNC gantry that we have modified to include a syringe pump, potentiostat, and camera with a telecentric lens. This system can perform fluid handling, electrochemistry, and transmission optical measurements on samples in custom 96-well plates that feature transparent and conducting bottoms. We begin by validating this platform through a series of control fluid handling and electrochemistry experiments to quantify the repeatability, lack of cross-contamination, and accuracy of the system. As a proof-of-concept experimental campaign to study the functional properties of a model polymer film, we optimize the electrochromic switching of electrodeposited poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films. In particular, we explore the monomer concentration, deposition time, and deposition voltage using an array of experiments selected by Latin hypercube sampling. Subsequently, we run an active learning campaign based upon Bayesian optimization to find the processing conditions that lead to the highest electrochromic switching of PEDOT:PSS. This self-driving lab integrates optical and electrochemical characterization to constitute a novel, automated approach for studying functional polymer films.

Effects of deep brain stimulation on quantitative sleep electroencephalogram during non-rapid eye movement in Parkinson's disease.

Introduction: Sleep dysfunction is frequently experienced by people with Parkinson's disease (PD) and negatively influences quality of life. Although subthalamic nucleus (STN) deep brain stimulation (DBS) can improve sleep in PD, sleep microstructural features such as sleep spindles provide additional insights about healthy sleep. For example, sleep spindles are important for better cognitive performance and for sleep consolidation in healthy adults. We hypothesized that conventional STN DBS settings would yield a greater enhancement in spindle density compared to OFF and low frequency DBS. Methods: In a previous within-subject, cross-sectional study, we evaluated effects of low (60 Hz) and conventional high (≥130 Hz) frequency STN DBS settings on sleep macroarchitectural features in individuals with PD. In this post hoc, exploratory analysis, we conducted polysomnography (PSG)-derived quantitative electroencephalography (qEEG) assessments in a cohort of 15 individuals with PD who had undergone STN DBS treatment a median 13.5 months prior to study participation. Fourteen participants had unilateral DBS and 1 had bilateral DBS. During three nonconsecutive nights of PSG, the participants were assessed under three different DBS conditions: DBS OFF, DBS LOW frequency (60 Hz), and DBS HIGH frequency (≥130 Hz). The primary objective of this study was to investigate the changes in sleep spindle density across the three DBS conditions using repeated-measures analysis of variance. Additionally, we examined various secondary outcomes related to sleep qEEG features. For all participants, PSG-derived EEG data underwent meticulous manual inspection, with the exclusion of any segments affected by movement artifact. Following artifact rejection, sleep qEEG analysis was conducted on frontal and central leads. The measures included slow wave (SW) and spindle density and morphological characteristics, SW-spindle phase-amplitude coupling, and spectral power analysis during non-rapid eye movement (NREM) sleep. Results: The analysis revealed that spindle density was significantly higher in the DBS HIGH condition compared to the DBS LOW condition. Surprisingly, we found that SW amplitude during NREM was significantly higher in the DBS LOW condition compared to DBS OFF and DBS HIGH conditions. However, no significant differences were observed in the other sleep qEEG features during sleep at different DBS conditions. Conclusion: This study presents preliminary evidence suggesting that conventional HIGH frequency DBS settings enhance sleep spindle density in PD. Conversely, LOW frequency settings may have beneficial effects on increasing slow wave amplitude during sleep. These findings may inform mechanisms underlying subjective improvements in sleep quality reported in association with DBS. Moreover, this work supports the need for additional research on the influence of surgical interventions on sleep disorders, which are prevalent and debilitating non-motor symptoms in PD.

Cauda equina syndrome: a review of the current clinical and medico-legal position.

Cauda equina syndrome (CES) is a rare condition with a disproportionately high medico-legal profile. It occurs most frequently following a large central lumbar disc herniation, prolapse or sequestration. Review of the literature indicates that around 50-70% of patients have urinary retention (CES-R) on presentation with 30-50% having an incomplete syndrome (CES-I). The latter group, especially if the history is less than a few days, usually requires emergency MRI to confirm the diagnosis followed by prompt decompression by a suitably experienced surgeon. Every effort should be made to avoid CES-I with its more favourable prognosis becoming CES-R while under medical supervision either before or after admission to hospital. The degree of urgency of early surgery in CES-R is still not in clear focus but it cannot be doubted that earliest decompression removes the mechanical and perhaps chemical factors which are the causes of progressive neurological damage. A full explanation and consent procedure prior to surgery is essential in order to reduce the likelihood of misunderstanding and litigation in the event of a persistent neurological deficit.

A Differential Pressure Instrument with Wireless Telemetry for In-Situ Measurement of Fluid Flow across Sediment-Water Boundaries.

An instrument has been built to carry out continuous in-situ measurement of small differences in water pressure, conductivity and temperature, in natural surface water and groundwater systems. A low-cost data telemetry system provides data on shore in real time if desired. The immediate purpose of measurements by this device is to continuously infer fluxes of water across the sediment-water interface in a complex estuarine system; however, direct application to assessment of sediment-water fluxes in rivers, lakes, and other systems is also possible. Key objectives of the design include both low cost, and accuracy of the order of ±0.5 mm H(2)O in measured head difference between the instrument's two pressure ports. These objectives have been met, although a revision to the design of one component was found to be necessary. Deployments of up to nine months, and wireless range in excess of 300 m have been demonstrated.

Graf ligamentoplasty: a 7-year follow-up.

Graf ligamentoplasty is seen as a means of stabilising and reducing the mobility of one or more severely symptomatic motion segments associated with degenerative disc disease. It is a less invasive procedure than fusion and appears to have a similar or slightly better success rate. Some studies have reported mixed results at early follow up; generally, they have suffered from poorly defined indications for the procedure, which are now much clearer. Reports on the first 50 patients undergoing Graf stabilisation in 1990/1991 were published in the European Spine Journal in 1995, with a 2-year follow-up. In the present study, the results of which were independently reviewed by the second author (K.C.P.), a spinal research fellow from an unrelated centre, we were able to establish postal contact with 40 of those patients, of whom 31 still had Graf instrumentation in situ. Examination of the clinical records of the ten non-responders when last seen indicated no particular bias of the results. The average age at surgery and average follow-up were 41.8 years (range 17.2-60 years) and 7.4 years (range 5.6-8.5 years) respectively. Excellent and good subjective results were reported in 62% of patients; 61% reported significant or total relief of low-back pain and 77% never or occasionally used analgesics. Patients were evaluated using the Oswestry Disability Score and the MSPQ (Modified Somatic Perception Questionnaire) and Zung Depression Index with the DRAM (Disability and Risk Assessment Method). Additional information was obtained from the clinical notes and radiographs at last review. The mean Oswestry Disability Score was 59+/-10% pre-operatively and 37.7+/-14% after 7 years. There was a statistically significant correlation between the Oswestry scores and the subjective outcome (P=0.009). The results of this study suggest that the beneficial effects of Graf ligamentoplasty are sustained in the longer term in spite of the presence of an established degenerative process.

Orthopaedic Specialist Registrar training and attitudes to spine surgery in the United Kingdom: reasons for poor recruitment and suggestions for improvement.

In order to improve the provision of spinal surgery in the United Kingdom, the number of Specialist Spinal Surgeons and Surgeons with an Interest in Spinal Surgery needs to increase by 25% from the existing 175 surgeons. A survey of Specialist Orthopaedic Registrars was performed, which quantifies the predicted shortfall in the number intending to practise spinal surgery. The attitudes towards and perceptions of this field were obtained to identify factors that could be discouraging an interest in spine surgery.