Novel surface electrode design for preferential activation of cutaneous nociceptors

Objective Small area electrodes enable preferential activation of nociceptive fibers. It is debated, however, whether co-activation of large fibers still occurs for the existing electrode designs. Moreover, existing electrodes are limited to low stimulation intensities, for which behavioral and physiological responses may be considered less reliable. A recent optimization study showed that there is a potential for improving electrode performance and increase the range of possible stimulation intensities. Based on those results, the present study introduces and tests a novel planar concentric array electrode design for small fiber activation in healthy volunteers. Approach Volunteers received electrical stimulation with the planar concentric array electrode and a regular patch electrode. Perception thresholds were estimated at the beginning and the end of the experiment. Evoked cortical potentials were recorded in blocks of 30 stimuli. For the patch, stimulation intensity was set to two times perception threshold (PT), while three intensities, 2, 5, and 10 times PT, were applied with the planar concentric array electrode. Sensation quality, numerical-rating scores, and reaction times were obtained for each PT estimation and during each block of evoked potential recordings. Main results Stimulation with the patch electrode was characterized as dull, while stimulation with the planar concentric array electrode was characterized as sharp, with increased sharpness for increasing stimulus intensity. Likewise, NRS scores were higher for the planar concentric array electrode compared to the patch and increased with increasing stimulation intensity. Reaction times and ERP latencies were longer for the planar concentric array electrode compared to the patch. Significance The presented novel planar concentric array electrode is a small, non-invasive, and single-use electrode that has the potential to investigate small fiber neuropathy and pain mechanisms, as it is small fiber preferential for a wide range of stimulation intensities.

The Combination Neuroprotective Abilities of Resveratrol and Naringenin in Attenuation of Sleep Deprivation Complications in Rats

Background: Sleep loss is one of the most important health problems in the world, and about 30 to 40 percent of ordinary people suffer from it. This study aimed to investigate the neuroprotective effects of the combination of resveratrol and naringenin in attenuation of sleep deprivation (SD) complications in rats. Materials and Methods: In this experimental study, 72 Wistar male rats were randomly divided into three main groups, including control, sham, and 7-days SD group. Each of its main groups consisted of three subgroups, including without drug, vehicle, and combination therapy groups (naringenin [100 mg/kg], resveratrol [100 mg/kg]). The day after the latest injection, the fear conditioning memory tests, locomotor activity test, hot plate, and forced swimming tests (FST) were carried out on all rats, and then sham and SD groups were induced 48 hours of non-REM SD (device off and on, respectively) and these behavioral tests were repeated for all rats again. Finally, the brains of all rats were removed and histopathologically examined, and stained with nissl and TUNNEL. Results: To assess fear condition memory, the rate of latency to first freezing in the visual and auditory phase increased in sham and SD rats that received vehicle or no drug (P<0.001), which indicates memory corruption. Injection of the combination of naringenin and resveratrol reduced the latency to first freezing (P<0.001), which means improved memory. In the FST test, injection of naringenin and resveratrol reduced the rate of immobility (P<0.001), which means improved depressive behavior. The naringenin and resveratrol reduced the pain perception threshold. Also, the naringenin and resveratrol reduced apoptosis compared to the control and vehicle groups (P<0.001). Conclusions: The combination of naringenin and resveratrol compared to other groups could improve memory and mood as well as reduce apoptosis, depression, and pain perception threshold. [GMJ.2021;10:e2315]

The perception threshold of the vestibular Coriolis illusion

BACKGROUND: The vestibular Coriolis illusion is a disorienting sensation that results from a transient head rotation about one axis during sustained body rotation about another axis. Although often used in spatial disorientation training for pilots and laboratory studies on motion sickness, little is known about the minimum required rotation rate to produce the illusion. OBJECTIVE: This study determined the perception threshold associated with the Coriolis illusion. METHODS: Nineteen participants performed a standardized pitching head movement during continuous whole-body yaw rotation at rates varying between 5 to 50 deg/s. The participants reported their motion sensation in relation to three hypothesized perception thresholds: 1) any sense of motion, 2) a sense of rotation, and 3) a sense of rotation and its direction (i.e., the factual Coriolis illusion). The corresponding thresholds were estimated from curves fitted by a generalized linear model. RESULTS: On average threshold 1 was significantly lower (8 deg/s) than thresholds 2 and 3. The latter thresholds did not differ from each other and their pooled value was 10 deg/s. CONCLUSIONS: The Coriolis illusion is perceived at yaw rates exceeding 10 deg/s using a pitching head movement with 40 deg amplitude and 55 deg/s peak velocity. Model analysis shows that this corresponds to an internal rotation vector of 6 deg/s. With this vector the Coriolis perception threshold can be predicted for any other head movement.

Imaging with [99mTc]HMPAO – a novel perspective: investigation of [99mTc]HMPAO leg muscle uptake in metabolic diseases

Background Sensitive imaging modalities in the diagnosis of microcircular complications of the lower extremities induced by metabolic diseases are becoming a focus of interest. Purpose To investigate the [99mTc]HMPAO uptake of the legs in type 2 diabetes mellitus (T2DM) and obesity, and to search for associations with clinical parameters and nerve conducting studies. Material and Methods A total of 57 patients with controlled T2DM and 46 obese participants without DM were enrolled in the study. [99mTc]HMPAO SPECT/CT examinations were performed to evaluate the radiopharmaceutical accumulation of the legs. For the quantitative assessment of tracer uptake, standardized uptake value (SUVpeak) was measured in fixed spheric volumes of interest placed on both sural muscles on the attenuation-corrected images. Measurement of current perception threshold applying Neurometer (NM-01/CPT) was used to evaluate peripheral nerve dysfunction. Laboratory parameters assessing the glucose homeostasis of the study participants were also measured. Results In the diabetic group, significantly lower leg SUV values were detected compared to the non-DM obese group (median: 0.517 vs. 0.607; P < 0.001). Body mass index (BMI) ( P < 0.0001), age ( P = 0.0283), HbA1c ( P = 0.0068), and glucose level ( P = 0.0044) proved to be significant predictors of muscle tracer uptake. Neurometer studies showed positive correlation with HbA1c levels in the T2DM group ( P = 0.0002). Conclusion We assume that [99mTc]HMPAO uptake of leg muscles is associated with microcirculation, so quantitative [99mTc]HMPAO SPECT/CT might be a sensitive method for evaluating lower limb microvascular alterations. BMI, age, HbA1c, and glucose level may be significant predictors of peripheral vascular abnormalities triggered by metabolic disturbances.

Enhanced flood hazard assessment beyond decadal climate cycles based on centennial historical data (Duero basin, Spain)

Current climate modelling frameworks present significant uncertainties when it comes to quantifying flood quantiles in the context of climate change, calling for new information and strategies in hazard assessments. Here, state-of-the-art methods on hydraulic and statistical modelling are applied to historical and contemporaneous flood records to evaluate flood hazards beyond natural climate cycles. A comprehensive flood record of the Duero River in Zamora (Spain) was compiled from documentary sources, early water-level readings and continuous gauge records spanning the last 500 years. Documentary evidence of flood events includes minute books (municipal and ecclesiastic), narrative descriptions, epigraphic marks, newspapers and technical reports. We identified 69 flood events over the period 1250 to 1871, of which 15 were classified as catastrophic floods, 16 as extraordinary floods and 38 as ordinary floods. Subsequently, a two-dimensional hydraulic model was implemented to relate flood stages (flood marks and inundated areas) to discharges. The historical flood records show the largest floods over the last 500 years occurred in 1860 (3450 m3 s−1), 1597 (3200 m3 s−1) and 1739 (2700 m3 s−1). Moreover, at least 24 floods exceeded the perception threshold of 1900 m3 s−1 during the period (1500–1871). Annual maximum flood records were completed with gauged water-level readings (pre-instrumental dataset, PRE: 1872–1919) and systematic gauge records (systematic dataset, SYS: 1920–2018). The flood frequency analyses were based on (1) the expected moments algorithm (EMA) and (2) the maximum likelihood estimator (MLE) method, using five datasets with different temporal frameworks (historic dataset, HISTO: 1511–2018; PRE–SYS: 1872–2018; full systematic record, ALLSYS: 1920–2018; SYS1: 1920–1969; and SYS2: 1970–2018). The most consistent results were obtained using the HISTO dataset, even for high quantiles (0.001 % annual exceedance probability, AEP). PRE–SYS was robust for the 1 % AEP flood with increasing uncertainty in the 0.2 % AEP or 500-year flood, and ALLSYS results were uncertain in the 1 % and 0.2 % AEP floods. Since the 1970s, the frequency of extraordinary floods (>1900 m3 s−1) declined, although floods on the range of the historical perception threshold occurred in 2001 (2075 m3 s−1) and 2013 (1654 m3 s−1). Even if the future remains uncertain, this bottom-up approach addresses flood hazards under climate variability, providing real and certain flood discharges. Our results can provide a guide on low-regret adaptation decisions and improve public perception of extreme flooding.

“Portugizac Mlado vino”; is the aroma of younger red wine more attractive?

“Portugizac Mlado vino” is a local red wine with Protected designation of origin and Traditional term, and it is usually consumed very soon after alcoholic fermentation as a young wine. The maturation and aging of the wine affect the aroma composition, which is generally not pronounced and specific in the case of most red wines, but, as a sensory property, it is important for the perception of quality and consumer choice. The objective of this work was to analyze the most important aroma compounds of esters and higher alcohols, with the unpleasant volatile phenols too, in “Portugizac” wines, related to aging. The 9 young wines “Portugizac”, PDO “Plešivica” were analyzed after 3 and after 15 months of bottle storage at 16 ºC. Ethyl esters of butanoic and hexanoic acid along with isoamyl acetate are considered to be the most important esters in the fruity aroma of wine, and their concentrations in all analyzed “Portugizac” young wine samples were higher than their perception thresholds. The concentration of ethyl acetate was in the range 30-123 mg/L. The concentrations of ethyl esters of octanoic and decanoic acid, as well as 2-phenyl ethyl acetate and diethyl succinate in all analyzed wines, were lower than their perception thresholds. The concentrations of higher alcohols were much higher than their perception threshold. Bottle storage significantly affected the concentrations of analyzed compounds; after 15 months, the concentrations of acetate and ethyl esters (except ethyl acetate and diethyl succinate), as well as terpene (linalool), decreased, while higher alcohols and ethyl phenols slightly increased if compared to three months. In general, the compounds responsible for the desired fresh, fruity aroma tones were altered in an undesirable manner, while, undesirable compounds of 4-ethyl-phenol and 4-ethyl-quaiacol, which were not present in young wines, were detected in aged wines. It can be concluded that the bottle aging affects the aroma profile, undesirable changes were more pronounced than positive ones and therefore the consumption of young wine “Portugizac” might be more sensory attractive.

Reliability of recommended non-invasive chairside screening tests for diabetes-related peripheral neuropathy: a systematic review with meta-analyses

The objective is to determine, by systematic review, the reliability of testing methods for diagnosis of diabetes-related peripheral neuropathy (DPN) as recommended by the most recent guidelines from the International Diabetes Foundation, International Working Group on the Diabetic Foot and American Diabetes Association. Electronic searches of Cochrane Library, EBSCO Megafile Ultimate and EMBASE were performed to May 2021. Articles were included if they reported on the reliability of recommended chairside tests in diabetes cohorts. Quality appraisal was performed using a Quality Appraisal of Reliability Studies checklist and where possible, meta-analyses, with reliability reported as estimated Cohen’s kappa (95% CI). Seventeen studies were eligible for inclusion. Pooled analysis found acceptable inter-rater reliability of vibration perception threshold (VPT) (κ=0.61 (0.50 to 0.73)) and ankle reflex testing (κ=0.60 (0.55 to 0.64)), but weak inter-rater reliability for pinprick (κ=0.45 (0.22 to 0.69)) and 128 Hz tuning fork (κ=0.42 (0.15 to 0.70)), though intra-rater reliability of the 128 Hz tuning fork was moderate (κ=0.54 (0.37 to 0.73)). Inter-rater reliability of the four-site monofilament was acceptable (κ=0.61 (0.45 to 0.77)). These results support the clinical use of VPT, ankle reflexes and four-site monofilament for screening and ongoing monitoring of DPN as recommended by the latest guidelines. The reliability of temperature perception, pinprick, proprioception, three-site monofilament and Ipswich touch test when performed in people with diabetes remains unclear.

Skin Advanced Glycation End Products among Subjects with Type 2 Diabetes Mellitus with or without Distal Sensorimotor Polyneuropathy

Aim of the Study. To examine the correlation between skin AGEs and parameters of distal sensorimotor polyneuropathy (DSPN) in type 2 diabetes mellitus (T2DM). Materials and Methods. We included 132 subjects (88 men) with a mean age of 64.57 years and median T2DM duration of 14.5 years. Skin AGEs were measured with AGE reader mu connect (Diagnoptics) on the dominant arm. The device enables single and automated triplicate measurements: both of these were performed. DSPN was diagnosed through the neuropathy disability score (NDS). Small nerve fibre function was assessed by temperature and pinprick sensation on the foot. Bilateral measurement of the vibration perception threshold (VPT) on the hallux was carried out by using a neurothesiometer (Horwell Scientific Laboratory Supplies). Results. Single and triplicate AGE measurements were positively correlated with each other (Pearson’s correlation coefficient r = 0.991 , 95 % CI = 0.987 -0.994, p < 0.001 ). AGEs were higher among subjects with vs. those without DSPN ( p < 0.001 ). Furthermore, they were higher among subjects with reduced vs. normal temperature sensation ( p < 0.001 ), among subjects with reduced vs. normal pinprick sensation ( p = 0.002 ), among those with abnormal vs. normal monofilament examination ( p < 0.001 ), and among those with abnormal vs. normal VPT ( p < 0.001 ). AGEs were correlated with NDS, VPT, and monofilament score. Conclusions. In T2DM, skin AGEs are increased in the presence of DSPN. This holds true both for large and for small nerve function impairment. Moreover, AGEs are correlated with DSPN severity.

Teacher Training Needs and their Influencing Factors: A Case Study of 13 Chinese Border School Teachers

Teacher training is not only the way to improve the quality of teachers in China's border areas, but also one of the collaborative paths to promote the high-quality development of regional education. Teacher training needs to provide a practical reference for specific service teacher training. Through conducting semi-structured, in-depth interviews, and using the grounded-theory three-level coding method for discourse analysis, this study explores teacher training needs and their influencing factors and how such factors influenced teacher learning and the development of teaching communities in border areas, in China. In the coding process, the researchers used MAXQDA (20.4.0) for auxiliary analysis. This work has constructed a model of teacher training needs and its influencing factors. Teacher training needs in border areas include training format, training content, training intensity, training opportunities, and training practicality. The factors include subjective factors, organizational development, institutional environmental factors, and field culture factors. According to the results of the model analysis, we put forward these optimization strategies: provide special mental health courses and counseling services for border teachers; carry out school-based training to form teachers' learning community; plan special training and create an international influence of border education, which would enhance teachers’ sense of professional honor and improve the perception threshold of achievement.