Event-Related Potentials of Single-Sided Deaf Cochlear Implant Users: Using a Semantic Oddball Paradigm in Noise.

INTRODUCTION: In individuals with single-sided deafness (SSD), who are characterised by profound hearing loss in one ear and normal hearing in the contralateral ear, binaural input is no longer present. A cochlear implant (CI) can restore functional hearing in the profoundly deaf ear, with previous literature demonstrating improvements in speech-in-noise intelligibility with the CI. However, we currently have limited understanding of the neural processes involved (e.g., how the brain integrates the electrical signal produced by the CI with the acoustic signal produced by the normal hearing ear) and how modulation of these processes with a CI contributes to improved speech-in-noise intelligibility. Using a semantic oddball paradigm presented in the presence of background noise, this study aims to investigate how the provision of CI impacts speech-in-noise perception of SSD-CI users. METHOD: Task performance (reaction time, reaction time variability, target accuracy, subjective listening effort) and high density electroencephalography from twelve SSD-CI participants were recorded, while they completed a semantic acoustic oddball task. Reaction time was defined as the time taken for a participant to press the response button after stimulus onset. All participants completed the oddball task in three different free-field conditions with the speech and noise coming from different speakers. The three tasks were: (1) CI-On in background noise, (2) CI-Off in background noise, and (3) CI-On without background noise (Control). Task performance and electroencephalography data (N2N4 and P3b) were recorded for each condition. Speech in noise and sound localisation ability were also measured. RESULTS: Reaction time was significantly different between all tasks with CI-On (M [SE] = 809 [39.9] ms) having faster RTs than CI-Off (M [SE] = 845 [39.9] ms) and Control (M [SE] = 785 [39.9] ms) being the fastest condition. The Control condition exhibited significantly shorter N2N4 and P3b area latency compared to the other two conditions. However, despite these differences noticed in RTs and area latency, we observed similar results between all three conditions for N2N4 and P3b difference area. CONCLUSION: The inconsistency between the behavioural and neural results suggests that EEG may not be a reliable measure of cognitive effort. This rationale is further supported by different explanations used in past studies to explain N2N4 and P3b effects. Future studies should look to alternative measures of auditory processing (e.g., pupillometry) to gain a deeper understanding of the underlying auditory processes that facilitate speech-in-noise intelligibility.

A Study of Event-Related Potentials During Monaural and Bilateral Hearing in Single-Sided Deaf Cochlear Implant Users.

OBJECTIVES: Single-sided deafness (SSD) is characterized by a profoundly deaf ear and normal hearing in the contralateral ear. A cochlear implant (CI) is the only method to restore functional hearing in a profoundly deaf ear. In a previous study, we identified that the cortical processing of a CI signal differs from the normal-hearing ear (NHE) when directly compared using an auditory oddball paradigm consisting of pure tones. However, exactly how the brain integrates the electrical and acoustic signal is not well investigated. This study aims to understand how the provision of the CI in combination with the NHE may improve SSD CI users' ability to discriminate and evaluate auditory stimuli. DESIGN: Electroencephalography from 10 SSD-CI participants (4 participated in the previous pure-tone study) were recorded during a semantic acoustic oddball task, where they were required to discriminate between odd and even numbers. Stimuli were presented in four hearing conditions: directly through the CI, directly to the NHE, or in free field with the CI switched on and off. We examined task-performance (response time and accuracy) and measured N1, P2, N2N4, and P3b event-related brain potentials (ERPs) linked to the detection, discrimination, and evaluation of task relevant stimuli. Sound localization and speech in noise comprehension was also examined. RESULTS: In direct presentation, task performance was superior during NHE compared with CI (shorter and less varied reaction times [~720 versus ~842 msec], higher target accuracy [~93 versus ~70%]) and early neural responses (N1 and P2) were enhanced for NHE suggesting greater signal saliency. However, the size of N2N4 and P3b target-standard effects did not differ significantly between NHE and CI. In free field, target accuracy was similarly high with the CI (FF-On) and without the CI (FF-Off) (~95%), with some evidence of CI interference during FF-On (more variable and slightly but significantly delayed reaction times [~737 versus ~709 msec]). Early neural responses and late effects were also greater during FF-On. Performance on sound localization and speech in noise comprehension (S CI N NHE configuration only) was significantly greater during FF-On. CONCLUSIONS: Both behavioral and neural responses in the semantic oddball task were sensitive to CI in both direct and free-field presentations. Direct conditions revealed that participants could perform the task with the CI alone, although performance was suboptimal and early neural responses were reduced when compared with the NHE. For free-field, the addition of the CI was associated with enhanced early and late neural responses, but this did not result in improved task performance. Enhanced neural responses show that the additional input from the CI is modulating relevant perceptual and cognitive processes, but the benefit of binaural hearing on behavior may not be realized in simple oddball tasks which can be adequately performed with the NHE. Future studies interested in binaural hearing should examine performance under noisy conditions and/or use spatial cues to allow headroom for the measurement of binaural benefit.

Engagement of the contralateral limb can enhance the facilitation of motor output by loud acoustic stimuli.

When intense sound is presented during light muscle contraction, inhibition of the corticomotoneuronal pathway is observed. During action preparation, this effect is reversed, with sound resulting in excitation of the corticomotoneuronal pathway. We investigated how the combined maintenance of a muscle contraction during preparation for a ballistic action impacts the magnitude of the facilitation of motor output by a loud acoustic stimulus (LAS), a phenomenon known as the StartReact effect. Participants executed ballistic wrist flexion movements and a LAS was presented simultaneously with the imperative signal in a subset of trials. We examined whether the force level or muscle used to maintain a contraction during preparation for the ballistic response impacted reaction time and/or the force of movements triggered by the LAS. These contractions were sustained either ipsilaterally or contralaterally to the ballistic response. The magnitude of facilitation by the LAS was greatest when low-force flexion contractions were maintained in the limb contralateral to the ballistic response during preparation. There was little change in facilitation when contractions recruited the contralateral extensor muscle or when they were sustained in the same limb that executed the ballistic response. We conclude that a larger network of neurons that may be engaged by a contralateral sustained contraction prior to initiation may be recruited by the LAS, further contributing to the motor output of the response. These findings may be particularly applicable in stroke rehabilitation, where engagement of the contralesional side may increase the benefits of a LAS to the functional recovery of movement.NEW & NOTEWORTHY The facilitation of reaction time, force, and vigor of a ballistic action by loud acoustic stimuli can be enhanced by the maintenance of a sustained contraction during preparation. This enhanced facilitation is observed when the sustained contraction is maintained with low force contralaterally and congruently with the ballistic response. This increased facilitation may be particularly applicable to rehabilitative applications of loud acoustic stimuli in improving the functional recovery of movement after neurological conditions such as stroke.

Great Northern Beans (Phaseolus vulgaris L.) Lower Cholesterol in Hamsters Fed a High-Saturated-Fat Diet.

BACKGROUND: Dietary interventions for high cholesterol, a primary risk factor for cardiovascular disease, are generally considered before prescribing drugs. OBJECTIVE: This study investigated the effects of whole Great Northern beans (wGNBs) and their hull (hGNB) incorporated into a high-saturated-fat (HSF) diet on cholesterol markers and hepatic/small intestinal genes involved in cholesterol regulation. METHODS: Each of the 4 groups of 11 male golden Syrian hamsters at 9 wk old were fed a normal-fat [NF; 5% (wt:wt) of soybean oil], HSF [5% (wt:wt) of soybean oil + 10% (wt:wt) of coconut oil], HSF+5% (wt:wt) wGNB, or HSF+0.5% (wt:wt) hGNB diet for 4 wk. Cholesterol markers and expression of genes involved in cholesterol metabolism and absorption were analyzed from plasma, liver, intestinal, and fecal samples. Data were analyzed by 1-factor ANOVA and Pearson correlations. RESULTS: Compared with the HSF group, the HSF+wGNB group had 62% and 85% lower plasma and liver cholesterol and 3.6-fold and 1.4-fold greater fecal excretion of neutral sterol and bile acid, respectively (P ≤ 0.05). The HSF+hGNB group had 54% lower plasma triglycerides (P < 0.001) and 53% lower liver esterified cholesterol (P = 0.0002) than the HSF group. Compared with the HSF group, the expression of small intestinal Niemann-Pick C1 like 1 (Npc1l1), acyl-coenzyme A:cholesterol acyltransferase 2 (Acat2), and ATP binding cassette transporter subfamily G member 5 (Abcg5) were 75%, 70%, and 49% lower, respectively, and expression of hepatic 3-hydroxy-3-methylglutaryl CoA reductase (Hmgr) was 11.5-fold greater in the HSF+wGNB group (P ≤ 0.05). CONCLUSIONS: Consumption of wGNBs resulted in lower cholesterol concentration in male hamsters fed an HSF diet by promoting fecal cholesterol excretion, most likely caused by Npc1l1 and Acat2 suppression. The hGNB may partially contribute to the cholesterol-lowering effect of the wGNBs.

Hydrophobic drug concentration affects the acoustic susceptibility of liposomes.

The purpose of this study was to investigate the effect of encapsulated hydrophobic drug concentration on ultrasound-mediated leakage from liposomes. Studies have shown that membrane modifications affect the acoustic susceptibility of liposomes, likely because of changes in membrane packing. An advantage of liposome as drug carrier is its ability to encapsulate drugs of different chemistries. However, incorporation of hydrophobic molecules into the bilayer may cause changes in membrane packing, thereby affecting the release kinetics. Liposomes containing calcein and varying concentrations of papaverine, a hydrophobic drug, were exposed to 20 kHz, 2.2 Wcm(-2) ultrasound. Papaverine concentration was observed to affect calcein leakage although the effects varied widely based on liposome phase. For example, incorporation of 0.5mg/mL papaverine into Ld liposomes increased the leakage of hydrophilic encapsulants by 3× within the first minute (p=0.004) whereas the same amount of papaverine increased leakage by only 1.5× (p<0.0001). Papaverine was also encapsulated into echogenic liposomes and its concentration did not significantly affect calcein release rates, suggesting that burst release from echogenic liposomes is predictable regardless of encapsulants chemistry and concentration.

Modeling and compensation of transmitter nonlinearity in coherent optical OFDM.

We present a comprehensive study of nonlinear distortions from an optical OFDM transmitter. Nonlinearities are introduced by the combination of effects from the digital-to-analog converter (DAC), electrical power amplifier (PA) and optical modulator in the presence of high peak-to-average power ratio (PAPR). We introduce parameters to quantify the transmitter nonlinearity. High input backoff avoids OFDM signal compression from the PA, but incurs high penalties in power efficiency. At low input backoff, common PAPR reduction techniques are not effective in suppressing the PA nonlinear distortion. A bit error distribution investigation shows a technique combining nonlinear predistortion with PAPR mitigation could achieve good power efficiency by allowing low input backoff. We use training symbols to extract the transmitter nonlinear function. We show that piecewise linear interpolation (PLI) leads to an accurate transmitter nonlinearity characterization. We derive a semi-analytical solution for bit error rate (BER) that validates the PLI approximation accurately captures transmitter nonlinearity. The inverse of the PLI estimate of the nonlinear function is used as a predistorter to suppress transmitter nonlinearity. We investigate performance of the proposed scheme by Monte Carlo simulations. Our simulations show that when DAC resolution is more than 4 bits, BER below forward error correction limit of 3.8 × 10(-3) can be achieved by using predistortion with very low input power backoff for electrical PA and optical modulator.

Pharmacist, nurse, and physician perspectives on the implementation of the pharmacist discharge care (pharm-dc) intervention: A qualitative study.

BACKGROUND: The PHARMacist Discharge Care (PHARM-DC) intervention is a pharmacist-led Transitions of Care (TOC) program intended to reduce 30-day hospital readmissions and emergency department visits which has been implemented at two hospitals in the United States. The objectives of this study were to: 1) explore perspectives surrounding the PHARM-DC program from healthcare providers, leaders, and administrators at both institutions, and 2) identify factors which may contribute to intervention success and sustainability. METHODS: Focus groups and interviews were conducted with pharmacists, physicians, nurses, hospital leaders, and pharmacy administrators at two institutions in the Northeastern and Western United States. Interviews were audio recorded and transcribed, with transcriptions imported into NVivo for qualitative analysis. Thematic analysis was performed using an iterative process, with two study authors independently coding transcripts to identify themes. RESULTS: Overall, 37 individuals participated in ten focus groups and seven interviews. The themes identified included: 1) Organizational, Pharmacist, and Patient Factors Contributing to Transitions of Care, 2) Medication Challenges in Transitions of Care at Admission and Discharge, 3) Transitions of Care Communication and Discharge Follow-up, and 4) Opportunities for Improvement and Sustainability. The four themes were mapped to the constructs of the CFIR and RE-AIM frameworks. Some factors facilitating intervention success and sustainability were accurate medication histories collected on admission, addressing medication barriers before discharge, coordinating discharge using electronic health record discharge features, and having a structured process for intervention training and delivery. Barriers to intervention implementation and sustainability included gaps in communication with other care team members, and variable pharmacist skills for delivering the intervention. This study identified that using educational resources to standardize the TOC process addressed the issue of variations in pharmacists' skills for delivering TOC interventions. CONCLUSIONS: Nurses, physicians, pharmacists, pharmacist leaders, and hospital administrators were in agreement regarding the usefulness of the PHARM-DC intervention, while acknowledging challenges in its implementation and opportunities for improvement. Future research should focus on developing training materials to standardize and scale the intervention, eliminating barriers to medication access pre-discharge, coordinating discharge across care team members, and communicating medication changes to primary care providers post-discharge.

Error vector magnitude based parameter estimation for digital filter back-propagation mitigating SOA distortions in 16-QAM.

We investigate the performance of digital filter back-propagation (DFBP) using coarse parameter estimation for mitigating SOA nonlinearity in coherent communication systems. We introduce a simple, low overhead method for parameter estimation for DFBP based on error vector magnitude (EVM) as a figure of merit. The bit error rate (BER) penalty achieved with this method has negligible penalty as compared to DFBP with fine parameter estimation. We examine different bias currents for two commercial SOAs used as booster amplifiers in our experiments to find optimum operating points and experimentally validate our method. The coarse parameter DFBP efficiently compensates SOA-induced nonlinearity for both SOA types in 80 km propagation of 16-QAM signal at 22 Gbaud.

Wideband wavelength conversion of 16 Gbaud 16-QAM and 5 Gbaud 64-QAM signals in a semiconductor optical amplifier.

We demonstrate wavelength conversion based on four-wave mixing in a semiconductor optical amplifier of signals with quadrature amplitude modulation (QAM). We first demonstrate wavelength conversion of 16 Gbaud 16-QAM signals over the entire C-band using two co-polarized pumps with low power penalty at the forward error correction threshold (FEC) for a wide range of input optical-signal-to-noise-ratio (OSNR). We also demonstrate for the first time wavelength conversion of 5 Gbaud 64-QAM signals in a semiconductor optical amplifier with bit-error rate below the FEC threshold over the entire C-band and investigate the dependence of the power penalty on input OSNR with a single pump configuration.

Evolving changes in cortical and subcortical excitability during movement preparation: A study of brain potentials and eye-blink reflexes during loud acoustic stimulation.

During preparation for action, the presentation of loud acoustic stimuli (LAS) can trigger movements at very short latencies in a phenomenon called the StartReact effect. It was initially proposed that a special, separate subcortical mechanism that bypasses slower cortical areas could be involved. We sought to examine the evidence for a separate mechanism against the alternative that responses to LAS can be explained by a combination of stimulus intensity effects and preparatory states. To investigate whether cortically mediated preparatory processes are involved in mediating reactions to LAS, we used an auditory reaction task where we manipulated the preparation level within each trial by altering the conditional probability of the imperative stimulus. We contrasted responses to non-intense tones and LAS and examined whether cortical activation and subcortical excitability and motor responses were influenced by preparation levels. Increases in preparation levels were marked by gradual reductions in reaction time (RT) coupled with increases in cortical activation and subcortical excitability - at both condition and trial levels. Interestingly, changes in cortical activation influenced motor and auditory but not visual areas - highlighting the widespread yet selective nature of preparation. RTs were shorter to LAS than tones, but the overall pattern of preparation level effects was the same for both stimuli. Collectively, the results demonstrate that LAS responses are indeed shaped by cortically mediated preparatory processes. The concurrent changes observed in brain and behavior with increasing preparation reinforce the notion that preparation is marked by evolving brain states which shape the motor system for action.

N1-P2 event-related potentials and perceived intensity are associated: The effects of a weak pre-stimulus and attentional load on processing of a subsequent intense stimulus.

A weak stimulus presented immediately before a more intense one reduces both the N1-P2 cortical response and the perceived intensity of the intense stimulus. The former effect is referred to as cortical prepulse inhibition (PPI), the latter as prepulse inhibition of perceived stimulus intensity (PPIPSI). Both phenomena are used to study sensory gating in clinical and non-clinical populations, however little is known about their relationship. Here, we investigated 1) the possibility that cortical PPI and PPIPSI are associated, and 2) how they are affected by attentional load. Participants were tasked with comparing the intensity of an electric pulse presented alone versus one preceded 200 ms by a weaker electric prepulse (Experiment 1), or an acoustic pulse presented alone with one preceded 170 ms by a weaker acoustic prepulse (Experiment 2). A counting task (easy vs. hard) manipulating attentional load was included in Experiment 2. In both experiments, we observed a relationship between N1-P2 amplitude and perceived intensity, where greater cortical PPI was associated with a higher probability of perceiving the 'pulse with prepulse' as less intense. Moreover, higher attentional load decreased observations of PPIPSI but had no effect on N1-P2 amplitude. Based on the findings we propose that PPIPSI partially relies on the allocation of attentional resources towards monitoring cortical channels that process stimulus intensity characteristics such as the N1-P2 complex.

Effect of the population health inpatient Medicare Advantage pharmacist intervention on hospital readmissions: A quasi-experimental controlled study.

BACKGROUND: The population health inpatient Medicare Advantage pharmacist (PHIMAP) intervention is a pharmacist-led, transitions-of-care intervention that aims to reduce hospital readmissions among Medicare Advantage beneficiaries. PHIMAP includes inpatient pharmacist participation in interdisciplinary rounds, admission and discharge medication reconciliation, pharmacy staff delivery of discharge medications to the bedside, personalized discharge medication lists and counseling, and communication with outpatient pharmacists through an electronic health record. OBJECTIVE: To evaluate the effect of the PHIMAP intervention on unplanned 30-day same-hospital readmissions among Medicare Advantage patients. METHODS: Those included were patients admitted to a large urban academic medical center between May 2018 and March 2020 who had a Medicare Advantage plan and were aged at least 18 years. A 2-group, quasi-experimental design was utilized. Control patients received the usual care, which included a best possible medication history and a postdischarge phone call. A multivariable logistic regression model was estimated to predict unplanned 30-day same-hospital readmissions. This study was a Hypothesis Evaluating Treatment Effectiveness study. RESULTS: In total, 884 patients were included. The majority were White (59.0%), non-Hispanic (87.7%), English speaking (90.5%), and older adults (median age, 75 years; interquartile range, 70-83 years). We detected no statistically significant association between the PHIMAP intervention and unplanned 30-day same-hospital readmissions (odds ratio [OR] = 0.91, 95% CI = 0.56-1.52). After adjusting for patient demographics and clinical covariates, significant predictors of 30-day readmissions included the number of emergency department/inpatient visits within 180 days prior to index admission (OR = 1.40, 95% CI = 1.11-1.77); discharge to a post-acute care facility, such as an inpatient rehabilitation facility, long-term acute care facility, or skilled nursing facility (OR = 1.69, 95% CI = 1.06-2.66); hospital length of stay in days (OR = 1.04, 95% CI=1.01-1.07); and the Agency for Healthcare Research and Quality Elixhauser Comorbidity Index score (OR = 1.01, 95% CI = 1.01-1.02). CONCLUSIONS: Significant predictors of readmissions among Medicare Advantage beneficiaries were consistent with greater illness severity, including a recent history of prior hospital utilization, a discharge to post-acute care facility (vs home), a longer length of hospital stay, and a higher comorbidity burden. Although we detected no statistically significant association between PHIMAP and unplanned 30-day same-hospital readmissions, differences in study group assignment based on the day of hospital discharge (weekend vs weekday) was a noted limitation of this study. Future studies of inpatient pharmacist-led interventions should plan to minimize the risk of selection bias due to differences in the time of patient discharge. DISCLOSURES: This study was supported in part by the National Institute on Aging under award number R01AG058911 (to Pevnick) and the UCLA Clinical Translational Science Institute (UL1 TR001881). The sponsor had no role in the design and conduct of the study, nor the writing of this report.

Comprehensive Pharmacist-led Transitions-of-care Medication Management around Hospital Discharge Adds Modest Cost Relative to Usual Care: Time-and-Motion Cost Analysis.

Optimal medication management is important during hospitalization and at discharge because post-discharge adverse drug events (ADEs) are common, often preventable, and contribute to patient harms, healthcare utilization, and costs. Conduct a cost analysis of a comprehensive pharmacist-led transitions-of-care medication management intervention for older adults during and after hospital discharge. Twelve intervention components addressed medication reconciliation, medication review, and medication adherence. Trained, experienced pharmacists delivered the intervention to older adults with chronic comorbidities at 2 large U.S. academic centers. To quantify and categorize time spent on the intervention, we conducted a time-and-motion analysis of study pharmacists over 36 sequential workdays (14 519 min) involving 117 patients. For 40 patients' hospitalizations, we observed all intervention activities. We used the median minutes spent and pharmacist wages nationally to calculate cost per hospitalization (2020 U.S. dollars) from the hospital perspective, relative to usual care. Pharmacists spent a median of 66.9 min per hospitalization (interquartile range 46.1-90.1), equating to $101 ($86 to $116 in sensitivity analyses). In unadjusted analyses, study site was associated with time spent (medians 111 and 51.8 min) while patient primary language, discharge disposition, number of outpatient medications, and patient age were not. In this cost analysis, comprehensive medication management around discharge cost about $101 per hospitalization, with variation across sites. This cost is at least an order of magnitude less than published costs associated with ADEs, hospital readmissions, or other interventions designed to reduce readmissions. Work is ongoing to assess the current intervention's effectiveness.

Seasonal weather, nutrients, and conspecific presence impacts on the southern house mosquito oviposition dynamics in combined sewage overflows.

Combined sewage overflows have created favorable conditions for the establishment of the southern house mosquito, Culex quinquefasciatus Say (Diptera: Culicidae), larvae in natural creeks that would otherwise be unsuitable for the development of this mosquito species. Here, we show the results from a seminatural experiment carried over the three seasons of mosquito activity (spring, summer, and fall) in Tanyard Creek, Atlanta, GA. In this study we manipulated the amount of nutrients by further enriching combined sewage overflow water, and tracked weather variables, organic nutrient concentration, exposure time to conspecifics, and the number of egg rafts collected in experimental containers. We found season and nutrient enrichment to be the most important variables explaining the differences in egg rafts counts. Further analyses suggest that temperature may also play a role in seasonal oviposition patterns. The results from this study suggest that nutrient enrichment and adequate temperatures are important factors shaping Cx. quinquefasciatus oviposition seasonality in combined sewage overflows.

Anodal-TDCS over Left-DLPFC Modulates Motor Cortex Excitability in Chronic Lower Back Pain.

Chronic pain is associated with abnormal cortical excitability and increased pain intensity. Research investigating the potential for transcranial direct current stimulation (tDCS) to modulate motor cortex excitability and reduce pain in individuals with chronic lower back pain (CLBP) yield mixed results. The present randomised, placebo-controlled study examined the impact of anodal-tDCS over left-dorsolateral prefrontal cortex (left-DLPFC) on motor cortex excitability and pain in those with CLBP. Nineteen participants with CLBP (Mage = 53.16 years, SDage = 14.80 years) received 20-min of sham or anodal tDCS, twice weekly, for 4 weeks. Short interval intracortical inhibition (SICI) and intracortical facilitation (ICF) were assessed using paired-pulse Transcranial Magnetic Stimulation prior to and immediately following the tDCS intervention. Linear Mixed Models revealed no significant effect of tDCS group or time, on SICI or ICF. The interactions between tDCS group and time on SICI and ICF only approached significance. Bayesian analyses revealed the anodal-tDCS group demonstrated higher ICF and SICI following the intervention compared to the sham-tDCS group. The anodal-tDCS group also demonstrated a reduction in pain intensity and self-reported disability compared to the sham-tDCS group. These findings provide preliminary support for anodal-tDCS over left-DLPFC to modulate cortical excitability and reduce pain in CLBP.

Odd-even oddball task: Evaluating event-related potentials during word discrimination compared to speech-token and tone discrimination.

Tonal and speech token auditory oddball tasks have been commonly used to assess auditory processing in various populations; however, tasks using non-word sounds may fail to capture the higher-level ability to interpret and discriminate stimuli based on meaning, which are critical to language comprehension. As such, this study examines how neural signals associated with discrimination and evaluation-processes (P3b) from semantic stimuli compare with those elicited by tones and speech tokens. This study comprises of two experiments, both containing thirteen adults with normal hearing in both ears (PTA ≤ 20 dB HL). Scalp electroencephalography and auditory event related potentials were recorded in free field while they completed three different oddball tasks: (1) tones, (2) speech tokens and (3) odd/even numbers. Based on the findings of experiment one, experiment two was conducted to understand if the difference in responses from the three tasks was attributable to stimulus duration or other factors. Therefore, in experiment one, stimulus duration was not controlled and in experiment two, the duration of each stimulus was modified to be the same across all three tasks (∼400 ms). In both experiments, P3b peak latency was significantly different between all three tasks. P3b amplitude was sensitive to reaction time, with tasks that had a large reaction time variability resulting in the P3b amplitude to be smeared, thereby reducing the amplitude size. The findings from this study highlight the need to consider all factors of the task before attributing any effects to any additional process, such as semantic processing and mental effort. Furthermore, it highlights the need for more cautious interpretation of P3b results in auditory oddball tasks.

Free-Standing, Interwoven Tubular Graphene Mesh-Supported Binary AuPt Nanocatalysts: An Innovative and High-Performance Anode Methanol Oxidation Catalyst.

Pt-based alloy or bimetallic anode catalysts have been developed to reduce the carbon monoxide (CO) poisoning effect and the usage of Pt in direct methanol fuel cells (DMFCs), where the second metal plays a role as CO poisoning inhibitor on Pt. Furthermore, better performance in DMFCs can be achieved by improving the catalytic dispersion and using high-performance supporting materials. In this work, we introduced a free-standing, macroscopic, interwoven tubular graphene (TG) mesh as a supporting material because of its high surface area, favorable chemical inertness, and excellent conductivity. Particularly, binary AuPt nanoparticles (NPs) can be easily immobilized on both outer and inner walls of the TG mesh with a highly dispersive distribution by a simple and efficient chemical reduction method. The TG mesh, whose outer and inner walls were decorated with optimized loading of binary AuPt NPs, exhibited a remarkably catalytic performance in DMFCs. Its methanol oxidation reaction (MOR) activity was 10.09 and 2.20 times higher than those of the TG electrodes with only outer wall immobilized with pure Pt NPs and binary AuPt NPs, respectively. Furthermore, the catalyst also displayed a great stability in methanol oxidation after 200 scanning cycles, implying the excellent tolerance toward the CO poisoning effect.

Crystal structure characterization and electronic structure of a rare-earth-containing Zintl phase in the Yb-Al-Sb family: Yb3AlSb3.

A rare-earth-containing compound, ytterbium aluminium antimonide, Yb3AlSb3 (Ca3AlAs3-type structure), has been successfully synthesized within the Yb-Al-Sb system through flux methods. According to the Zintl formalism, this structure is nominally made up of (Yb2+)3[(Al1-)(1b - Sb2-)2(2b - Sb1-)], where 1b and 2b indicate 1-bonded and 2-bonded, respectively, and Al is treated as part of the covalent anionic network. The crystal structure features infinite corner-sharing AlSb4 tetrahedra, [AlSb2Sb2/2]6-, with Yb2+ cations residing between the tetrahedra to provide charge balance. Herein, the synthetic conditions, the crystal structure determined from single-crystal X-ray diffraction data, and electronic structure calculations are reported.

Cochlear implants in single-sided deaf recipients: Near normal higher-order processing.

OBJECTIVE: Single-sided deafness (SSD) is a condition where an individual has a severe to profound sensorineural hearing loss in one ear and normal hearing on the contralateral side. The use of cochlear implants in individuals with SSD leads to functional improvements in hearing. However, it is relatively unclear how sounds incoming via the cochlear implant (independent of the hearing ear) are processed and interpreted by higher-order processes in the brain. METHODS: Scalp electroencephalography and auditory event-related potentials were recorded monaurally from nine experienced single sided cochlear implant users. Speech-in-noise and localisation tests were used to measure functional changes in hearing. RESULTS: cochlear implant use was associated with improvement in speech-in-noise and localisation tests (compared to cochlear implant off). Significant N2 and P3b effects were observed in both cochlear implant and normal hearing ear conditions, with similar waveform morphology and scalp distribution across conditions. Delayed response times and a reduced N2 (but not P3b) effect was measured in the CI condition. CONCLUSION: The brain is capable of using processes similar to those in normal hearing to discriminate sounds presented to the cochlear implant. There was evidence of processing difficulty in the cochlear implant condition which could be due to the relatively degraded signals produced by the cochlear implant compared to the normal hearing ear. SIGNIFICANCE: Understanding how the brain processes sound provided by a cochlear implant highlights how cortical responses can be used to guide implantation candidacy guidelines and influence rehabilitation recommendations.

Preparatory suppression and facilitation of voluntary and involuntary responses to loud acoustic stimuli in an anticipatory timing task.

In this study, we sought to characterize the effects of intense sensory stimulation on voluntary and involuntary behaviors at different stages of preparation for an anticipated action. We presented unexpected loud acoustic stimuli (LAS) at-rest and at three critical times during active movement preparation (-1,192, -392, and 0 ms relative to expected voluntary movement onset) to probe the state of the nervous system, and measured their effect on voluntary and involuntary motor actions (finger-press and eye-blink startle reflex, respectively). Voluntary responses were facilitated by LAS presented during active preparation, leading to earlier and more forceful responses compared to control and LAS at-rest. Notably, voluntary responses were significantly facilitated on trials where the LAS was presented early during preparation (-1,192 ms). Eye-blink reflexes to the LAS at -392 ms were significantly reduced and delayed compared to blinks elicited at other time-points, indicating suppression of sub-cortical excitability. However, voluntary responses on these trials were still facilitated by the LAS. The results provide insight into the mechanisms involved in preparing anticipatory actions. Induced activation can persist in the nervous system and can modulate subsequent actions for a longer time-period than previously thought, highlighting that movement preparation is a continuously evolving process that is susceptible to external influence throughout the preparation period. Suppression of sub-cortical excitability shortly before movement onset is consistent with previous work showing corticospinal suppression which may be a necessary step before the execution of any voluntary response.