Retrospective Review of the Efficacy of Lumbar Radiofrequency Ablation for Lumbar Facet Arthropathy: The Influence of Gender and Obesity.

BACKGROUND: Lumbar facet arthropathy is one of the leading causes of back pain. Lumbar radiofrequency lesioning is a therapy for lumbar facet arthropathy that uses heat to ablate the transmission of nerve signals from the medial branches of the spinal nerves associated with the corresponding painful lumbar joints. OBJECTIVES: The present investigation evaluated the outcomes of patients undergoing lumbar radiofrequency ablation at an academic pain program with a special focus on the influence of gender and obesity. STUDY DESIGN: Retrospective chart review. SETTING: Academic tertiary care center. METHODS: We reviewed the charts of 232 patients for age, body mass index, gender, other procedures, and complications, in addition to the primary outcome measurements of Visual Analog Scale pain scores, pain relief percentages, pain relief duration, and functional status improvement per patient report. Associations with outcomes were evaluated with correlations, t tests/analysis of variance, and c2 test. Influences on a change in Visual Analog Scale pain scores before and after treatment were assessed with linear regression. RESULTS: Patients had an average pain reduction of 76.6% (SD = 24.5) from the initial treatment and an average of 30.7 weeks (SD = 21.2) of pain relief from the initial treatment. A total of 83% of the patients reported an improvement in functional status from the initial treatment. Women (mean = 79.8%, SD = 21.4) had a slightly higher pain relief percentage than men (mean = 71.6%, SD = 28.1; P = 0.046). A higher body mass index was associated with less improvement in Visual Analog Scale maximum pain scores from before and after the procedure (b = 0.04; SE = 0.02; P = 0.042). LIMITATIONS: Our study is not a randomized controlled trial; however, based on the number of patients reviewed, our data provide important information regarding lumbar radiofrequency ablations. CONCLUSIONS: This study highlights significant effectiveness for patients undergoing lumbar radiofrequency ablations for lumbar facet joint pain. A variation in effectiveness appears to be influenced by gender and obesity, and therefore additional studies are warranted to further investigate these differences.

Dolphins reduce hearing sensitivity in anticipation of repetitive impulsive noise exposures.

The auditory steady-state response (ASSR) was continuously measured in two bottlenose dolphins during impulse noise exposures to determine whether observed head movements coincided with actual changes to auditory system sensitivity. Impulses were generated by a seismic air gun at a fixed inter-pulse interval of 10 s. ASSR amplitudes were extracted from the instantaneous electroencephalogram using coherent averaging within a sliding analysis window. A decline in ASSR amplitude was seen during the time interval between air gun impulses, followed by an elevation in ASSR amplitude immediately after each impulse. Similar patterns were not observed during control trials where air gun impulses were not generated. The results suggest that the dolphins learned the timing of the impulse noise sequences and lowered their hearing sensitivity before each impulse, presumably to lessen the auditory effects of the noise. The specific mechanisms responsible for the observed effects are at present unknown.

Bringing the outside in: The feasibility of virtual reality with people with dementia in an inpatient psychiatric care setting.

BACKGROUND AND OBJECTIVES: Emerging research supports virtual reality use with people with dementia in the community, but is limited to this area, warranting further investigation in different care settings. The feasibility of virtual reality within an inpatient psychiatric care setting was therefore explored.Research design and methods: Eight people with dementia and 16 caregivers were recruited in January and February 2018 from a UK hospital specialising in progressive neurological conditions. A mixed methods design measured affect and behaviour using the Observed Emotion Rating Scale, Overt Aggression Scale-Modified for Neurorehabilitation and St Andrew's Sexual Behaviour Assessment. Thematic analysis was conducted following semi-structured interviews. Caregivers who worked at the hospital supported people with dementia throughout the process and were interviewed for their views on Head Mounted Display-Virtual Reality (HMD-VR) use with people with dementia. RESULTS: HMD-VR was tried and accepted by people with dementia. Participants viewed HMD-VR positively as a 'change in environment' and would use it again. People with dementia experienced more pleasure during and after HMD-VR compared to before exposure, as well as increased alertness after. Three core themes emerged: 'Virtual Reality Experiences', 'Impact of Virtual Reality' and 'Experiences within the Virtual Environment'. Caregivers discussed preconceptions about virtual reality use and how these changed.Discussion and implications: This is the first study to explore the feasibility of HMD-VR with people with mild to moderately severe dementia in hospital and found that overall HMD-VR is viable. Findings evidence the clinical feasibility of HMD-VR implementation in this environment and inform future research.

Optimizing measurement for neurobehavioural rehabilitation services: A multisite comparison study and response to UKROC.

To evaluate the efficacy of neurobehavioural rehabilitation (NbR) programmes, services should employ valid, reliable assessment tools; the ability to detect change on repeated assessment is a particular requirement. The United Kingdom Rehabilitation Outcomes Collaborative (UKROC) requires neurorehabilitation services to collect data using a standardized basket of measures, but the responsiveness and usefulness of using these in the context of NbR remains unknown. Anonymous data collected at two assessments for 123 people were examined using multiple methods to determine responsiveness of four outcome measures routinely used in NbR (HoNOS-ABI, FIM + FAM UK, MPAI-4, SASNOS). Predictive validity of two measures of rehabilitation complexity (RCS-E, SRS) regarding the extent of difference scores on these outcome measures at reassessment was also determined. All four outcome measures demonstrated responsiveness, with higher levels for SASNOS and MPAI-4 when only participants categorized as "most likely to change" at first assessment were analyzed. Predictive validity of the RCS-E and SRS in estimating the extent of change was variable. SRS was only predictive of improvement on the MPAI-4 whilst RCS-E was not predictive at all. Recommendations are made regarding ideal characteristics of NbR outcome measures, along with the need to develop measures of rehabilitation complexity specifically conceptualized for these programmes.

Effects of vibratory pile driver noise on echolocation and vigilance in bottlenose dolphins (Tursiops truncatus).

Vibratory pile drivers, used for marine construction, can produce sustained, high sound pressure levels (SPLs) in areas that overlap with dolphin habitats. Dolphins rely on echolocation for navigation, detecting predators and prey, and to coordinate group behavior. This study examined the effects of vibratory pile driver noise on dolphin sustained target detection capabilities through echolocation. Five dolphins were required to scan their enclosure and indicate the occurrences of phantom echoes during five different source levels of vibratory pile driver playback sound (no-playback control, 110, 120, 130, and 140 dB re 1 µPa). Three of the dolphins demonstrated a significant decrease in target detection performance at 140 dB playback level that was associated with an almost complete secession of echolocation activity. The performance of two dolphins was not affected. All dolphins rapidly returned to baseline levels of target detection performance by their second replication. However, an increased number of clicks was produced at the highest playback SPL. The data suggest that the decrease in vigilant behavior was due to the vibratory pile driver noise distracting the dolphins and decreasing their motivation to perform the task.

High-speed logic integrated circuits with solution-processed self-assembled carbon nanotubes.

As conventional monolithic silicon technology struggles to meet the requirements for the 7-nm technology node, there has been tremendous progress in demonstrating the scalability of carbon nanotube field-effect transistors down to the size that satisfies the 3-nm node and beyond. However, to date, circuits built with carbon nanotubes have overlooked key aspects of a practical logic technology and have stalled at simple functionality demonstrations. Here, we report high-performance complementary carbon nanotube ring oscillators using fully manufacturable processes, with a stage switching frequency of 2.82 GHz. The circuit was built on solution-processed, self-assembled carbon nanotube arrays with over 99.9% semiconducting purity, and the complementary feature was achieved by employing two different work function electrodes.

Killer whale (Orcinus orca) behavioral audiograms.

Killer whales (Orcinus orca) are one of the most cosmopolitan marine mammal species with potential widespread exposure to anthropogenic noise impacts. Previous audiometric data on this species were from two adult females [Szymanski, Bain, Kiehl, Pennington, Wong, and Henry (1999). J. Acoust. Soc. Am. 108, 1322-1326] and one sub-adult male [Hall and Johnson (1972). J. Acoust. Soc. Am. 51, 515-517] with apparent high-frequency hearing loss. All three killer whales had best sensitivity between 15 and 20 kHz, with thresholds lower than any odontocete tested to date, suggesting this species might be particularly sensitive to acoustic disturbance. The current study reports the behavioral audiograms of eight killer whales at two different facilities. Hearing sensitivity was measured from 100 Hz to 160 kHz in killer whales ranging in age from 12 to 52 year. Previously measured low thresholds at 20 kHz were not replicated in any individual. Hearing in the killer whales was generally similar to other delphinids, with lowest threshold (49 dB re 1 µPa) at approximately 34 kHz, good hearing (i.e., within 20 dB of best sensitivity) from 5 to 81 kHz, and low- and high-frequency hearing cutoffs (>100 dB re µPa) of 600 Hz and 114 kHz, respectively.

Auditory Effects of Multiple Impulses from a Seismic Air Gun on Bottlenose Dolphins (Tursiops truncatus).

Auditory thresholds were measured in three bottlenose dolphins before and after exposure to ten impulses from a seismic air gun. Thresholds were measured using behavioral and electrophysiological methods to determine the amount of temporary threshold shift induced. The results suggest that the potential for seismic surveys using air guns to cause auditory effects on dolphins may be lower than previously predicted; however, two of the three dolphins exhibited "anticipatory" behavioral changes at the highest exposure condition that suggested they were attempting to mitigate the effects of the exposures.

Effects of multiple impulses from a seismic air gun on bottlenose dolphin hearing and behavior.

To investigate the auditory effects of multiple underwater impulses, hearing thresholds were measured in three bottlenose dolphins before and after exposure to 10 impulses produced by a seismic air gun. Thresholds were measured at multiple frequencies using both psychophysical and electrophysiological (auditory evoked potential) methods. Exposures began at relatively low levels and gradually increased over a period of several months. The highest exposures featured peak sound pressure levels from 196 to 210 dB re 1 µPa, peak-peak sound pressure levels of 200-212 dB re 1 µPa, and cumulative (unweighted) sound exposure levels from 193 to 195 dB re 1 µPa(2)s. At the cessation of the study, no significant increases were observed in psychophysical thresholds; however, a small (9 dB) shift in mean auditory evoked potential thresholds, accompanied by a suppression of the evoked potential amplitude function, was seen in one subject at 8 kHz. At the highest exposure condition, two of the dolphins also exhibited behavioral reactions indicating that they were capable of anticipating and potentially mitigating the effects of impulsive sounds presented at fixed time intervals.

Ethylene signalling affects susceptibility of tomatoes to Salmonella.

Fresh fruits and vegetables are increasingly recognized as important reservoirs of human pathogens, and therefore, significant attention has been directed recently to understanding mechanisms of the interactions between plants and enterics, like Salmonella. A screen of tomato cultivars for their susceptibility to Salmonella revealed significant differences in the ability of this human pathogen to multiply within fruits; expression of the Salmonella genes (cysB, agfB, fadH) involved in the interactions with tomatoes depended on the tomato genotype and maturity stage. Proliferation of Salmonella was strongly reduced in the tomato mutants with defects in ethylene synthesis, perception and signal transduction. While mutation in the ripening-related ethylene receptor Nr resulted only in a modest reduction in Salmonella numbers within tomatoes, strong inhibition of the Salmonella proliferation was observed in rin and nor tomato mutants. RIN and NOR are regulators of ethylene synthesis and ripening. A commercial tomato variety heterozygous for rin was less susceptible to Salmonella under the greenhouse conditions but not when tested in the field over three production seasons.

Graphene radio frequency receiver integrated circuit.

Graphene has attracted much interest as a future channel material in radio frequency electronics because of its superior electrical properties. Fabrication of a graphene integrated circuit without significantly degrading transistor performance has proven to be challenging, posing one of the major bottlenecks to compete with existing technologies. Here we present a fabrication method fully preserving graphene transistor quality, demonstrated with the implementation of a high-performance three-stage graphene integrated circuit. The circuit operates as a radio frequency receiver performing signal amplification, filtering and downconversion mixing. All circuit components are integrated into 0.6 mm(2) area and fabricated on 200 mm silicon wafers, showing the unprecedented graphene circuit complexity and silicon complementary metal-oxide-semiconductor process compatibility. The demonstrated circuit performance allow us to use graphene integrated circuit to perform practical wireless communication functions, receiving and restoring digital text transmitted on a 4.3-GHz carrier signal.

Use of the Multiple Errands Test-Simplified Version in the assessment of suboptimal effort.

Most measures of suboptimal effort focus on short-term learning; fewer studies have considered non-memory feigned cognitive impairment. This study investigated the utility of the Multiple Errands Test - Simplified Version (MET-SV) in the detection of feigned executive functioning impairment. Performance of simulating malingerers (N = 47) was compared to acquired brain injury (N = 46) and neurologically healthy control groups (N = 50). Although simulating malingerers were successful at feigning a realistic level of impairment compared to the brain injury group, there were significant differences regarding pattern of performance. A logistic regression model successfully classified 84% of simulating malingerers and 74.5% of brain injured individuals. Receiver Operating Characteristic (ROC) analysis supported the discriminatory power of the model. The current study is unique in yielding some understanding of the real-life observation of suspected malingerers compared to individuals with genuine cognitive difficulties. Results suggest the MET-SV can contribute to the clinical assessment of individuals suspected of suboptimal effort in the domain of executive functioning. Further research is needed to establish whether the MET-SV can be reliably used in medico-legal settings.

Current saturation in submicrometer graphene transistors with thin gate dielectric: experiment, simulation, and theory.

Recently, graphene field-effect transistors (FET) with cutoff frequencies (f(T)) between 100 and 300 GHz have been reported; however, the devices showed very weak drain current saturation, leading to an undesirably high output conductance (g(ds)= dI(ds)/dV(ds)). A crucial figure-of-merit for analog/RF transistors is the intrinsic voltage gain (g(m)/g(ds)) which requires both high g(m) (primary component of f(T)) and low g(ds). Obtaining current saturation has become one of the key challenges in graphene device design. In this work, we study theoretically the influence of the dielectric thickness on the output characteristics of graphene FETs by using a surface-potential-based device model. We also experimentally demonstrate that by employing a very thin gate dielectric (equivalent oxide thickness less than 2 nm), full drain current saturation can be obtained for large-scale chemical vapor deposition graphene FETs with short channels. In addition to showing intrinsic voltage gain (as high as 34) that is comparable to commercial semiconductor FETs with bandgaps, we also demonstrate high frequency AC voltage gain and S21 power gain from s-parameter measurements.

State-of-the-art graphene high-frequency electronics.

High-performance graphene transistors for radio frequency applications have received much attention and significant progress has been achieved. However, devices based on large-area synthetic graphene, which have direct technological relevance, are still typically outperformed by those based on mechanically exfoliated graphene. Here, we report devices with intrinsic cutoff frequency above 300 GHz, based on both wafer-scale CVD grown graphene and epitaxial graphene on SiC, thus surpassing previous records on any graphene material. We also demonstrate devices with optimized architecture exhibiting voltage and power gains reaching 20 dB and a wafer-scale integrated graphene amplifier circuit with voltage amplification.

High-frequency graphene voltage amplifier.

While graphene transistors have proven capable of delivering gigahertz-range cutoff frequencies, applying the devices to RF circuits has been largely hindered by the lack of current saturation in the zero band gap graphene. Herein, the first high-frequency voltage amplifier is demonstrated using large-area chemical vapor deposition grown graphene. The graphene field-effect transistor (GFET) has a 6-finger gate design with gate length of 500 nm. The graphene common-source amplifier exhibits ∼5 dB low frequency gain with the 3 dB bandwidth greater than 6 GHz. This first AC voltage gain demonstration of a GFET is attributed to the clear current saturation in the device, which is enabled by an ultrathin gate dielectric (4 nm HfO(2)) of the embedded gate structures. The device also shows extrinsic transconductance of 1.2 mS/µm at 1 V drain bias, the highest for graphene FETs using large-scale graphene reported to date.

Wafer-scale graphene integrated circuit.

A wafer-scale graphene circuit was demonstrated in which all circuit components, including graphene field-effect transistor and inductors, were monolithically integrated on a single silicon carbide wafer. The integrated circuit operates as a broadband radio-frequency mixer at frequencies up to 10 gigahertz. These graphene circuits exhibit outstanding thermal stability with little reduction in performance (less than 1 decibel) between 300 and 400 kelvin. These results open up possibilities of achieving practical graphene technology with more complex functionality and performance.

High-frequency, scaled graphene transistors on diamond-like carbon.

Owing to its high carrier mobility and saturation velocity, graphene has attracted enormous attention in recent years. In particular, high-performance graphene transistors for radio-frequency (r.f.) applications are of great interest. Synthesis of large-scale graphene sheets of high quality and at low cost has been demonstrated using chemical vapour deposition (CVD) methods. However, very few studies have been performed on the scaling behaviour of transistors made from CVD graphene for r.f. applications, which hold great potential for commercialization. Here we report the systematic study of top-gated CVD-graphene r.f. transistors with gate lengths scaled down to 40 nm, the shortest gate length demonstrated on graphene r.f. devices. The CVD graphene was grown on copper film and transferred to a wafer of diamond-like carbon. Cut-off frequencies as high as 155 GHz have been obtained for the 40-nm transistors, and the cut-off frequency was found to scale as 1/(gate length). Furthermore, we studied graphene r.f. transistors at cryogenic temperatures. Unlike conventional semiconductor devices where low-temperature performance is hampered by carrier freeze-out effects, the r.f. performance of our graphene devices exhibits little temperature dependence down to 4.3 K, providing a much larger operation window than is available for conventional devices.

Utilization of a buffered dielectric to achieve high field-effect carrier mobility in graphene transistors.

We utilize an organic polymer buffer layer between graphene and conventional gate dielectrics in top-gated graphene transistors. Unlike other insulators, this dielectric stack does not significantly degrade carrier mobility, allowing for high field-effect mobilities to be retained in top-gate operation. This is demonstrated in both two-point and four-point analysis and in the high-frequency operation of a graphene transistor. Temperature dependence of the carrier mobility suggests that phonons are the dominant scatterers in these devices.

Retrograde amnesia and malingering.

PURPOSE OF REVIEW: Malingered anterograde amnesia is a phenomenon that has been exhaustively studied, whereas research on retrograde amnesia has tended to focus upon functional and organic accounts of impairment. The present review explores studies relevant to extending the malingering paradigm to retrograde amnesia. RECENT FINDINGS: In the period reviewed, very little work has directly addressed the area of malingered retrograde amnesia. Researchers have tended to explain apparent 'anomalies' in memory performance or individual presentation, as manifestations of unconscious or psychological distress-mediated behaviour. In contrast, research with offenders claiming amnesia for their crimes has emphasized that malingered retrograde amnesia can be identified with relevant assessment methods. Brain imaging work too has begun to clearly describe the associated neural processes that underlie deception. It appears that the necessary coalescence of insights from clinical neuropsychology, brain imaging and neurology has reached a critical moment. SUMMARY: Current and previous studies are reviewed that addresses the assessment of malingered retrograde amnesia and evidences that a critical moment has been reached.

Operation of graphene transistors at gigahertz frequencies.

Top-gated graphene transistors operating at high frequencies (gigahertz) have been fabricated and their characteristics analyzed. The measured intrinsic current gain shows an ideal 1/f frequency dependence, indicating a FET-like behavior for graphene transistors. The cutoff frequency f(T) is found to be proportional to the dc transconductance g(m) of the device, consistent with the relation f(T) = g(m)/(2piC(G)). The peak f(T) increases with a reduced gate length, and f(T) as high as 26 GHz is measured for a graphene transistor with a gate length of 150 nm. The work represents a significant step toward the realization of graphene-based electronics for high-frequency applications.