Elucidating the Electrochemical Mechanism of NG-Hydroxy-L-arginine.

NG-Hydroxy-L-arginine (NOHA) is a stable intermediate product in the urea cycle that can be used to monitor the consumption of L-arginine by nitrous oxide synthase (NOS) to produce nitric oxide (NO) and L-citrulline. Research has implicated the urea cycle in many diseases and NO has cultivated interest as a potential biomarker for neural health. Electrochemical detection is an established, cost-effective method that can successfully detect low levels of analyte concentrations. As one of the few electrochemically active species in the urea cycle, NOHA shows promise as a biomarker for monitoring disruptions in this biochemical process. In this study, we show that NOHA has an oxidation peak at +355 mV vs Ag/AgCl at a glassy carbon electrode. In addition, cyclic voltammetry studies with structural analogs - alanine and N-hydroxyguanidine - allowed us to approximate the oxidation wave at +355 mV vs Ag/AgCl to be a one electron process. Diffusivity of NOHA was found using linear scan voltammetry with a rotating disk electrode and approximated at 5.50×10-5 cm2/s. Ample work is still needed to make a robust biosensor, but the results here characterize the electrochemical activity and represent principle steps in making a NOHA biosensor.

Electrochemical characterization of the stimuli-response of surface-immobilized elastin-like polymers.

Elastin-like polymers (ELPs) are frequently used in a variety of bioengineering applications because of their stimuli-responsive properties. Above their transition temperature, ELPs will adopt different structures that promote intra- and intermolecular hydrophobic contacts to minimize unfavorable interactions with an aqueous environment. We electrochemically characterize the stimuli-responsive behavior of surface-immobilized ELPs corresponding to two proposed states: extended and collapsed. In the extended state the ELPs are more solvated. In the collapsed state, triggered by introducing an environmental stimulus, non-polar intramolecular contacts within ELPs are favored, resulting in quantifiable morphological changes on the surface characterized using electrochemical impedance spectroscopy (EIS). Charge transfer resistance, a component of impedance, was shown to increase after exposing an ELP modified electrode to a high salt concentration environment (3.0 M NaCl). An increase in charge transfer resistance indicates an increase in the insulating layer on the electrode surface consistent with the proposed mechanism of collapse, as the ELPs have undergone morphological changes to hinder the kinetics of the redox couple exchange. Further characterization of the surface-immobilized ELPs showed a reproducible surface modification, as well as reversibility and tunability of the stimuli-response.

Guide to Selecting a Biorecognition Element for Biosensors.

Biosensors are powerful diagnostic tools defined as having a biorecognition element for analyte specificity and a transducer for a quantifiable signal. There are a variety of different biorecognition elements, each with unique characteristics. Understanding the advantages and disadvantages of each biorecognition element and their influence on overall biosensor performance is crucial in the planning stages to promote the success of novel biosensor development. Therefore, this review will focus on selecting the optimal biorecognition element in the preliminary design phase for novel biosensors. Included is a review of the typical characteristics and binding mechanisms of various biorecognition elements, and how they relate to biosensor performance characteristics, specifically sensitivity, selectivity, reproducibility, and reusability. The goal is to point toward language needed to improve the design and development of biosensors toward clinical success.

Evaluation of Metal Oxide Surface Catalysts for the Electrochemical Activation of Amino Acids.

Electrochemical detection of amino acids is important due to their correlation with certain diseases; however, most amino acids require a catalyst to electrochemically activate. One common catalyst for electrochemical detection of amino acids are metal oxides. Metal oxide nanoparticles were electrodeposited onto glassy carbon and platinum working electrodes. Cyclic voltammetry (CV) experiments in a flow cell were performed to evaluate the sensors' ability to detect arginine, alanine, serine, and valine at micromolar and nanomolar concentrations as high as 4 mM. Solutions were prepared in phosphate buffer saline (PBS) and then 100 mM NaOH. Specifically, NiO surfaces were responsive to amino acids but variable, especially when exposed to arginine. Polarization resistance experiments and scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) data indicated that arginine accelerated the corrosion of the NiO catalyst through the formation of a Schiff base complex.

Soil-transmitted helminthiases in secondary school students in selected sites in two provinces in the Philippines: policy implications.

The latest World Health Organization (WHO) strategic plan for eliminating soil-transmitted helminthiases (STHs) as a public health problem in children puts the emphasis on school-age children. On the other hand, the Philippine national helminth control program excludes secondary school students in mass deworming for STH. This study determined the prevalence and intensity of STH in a sample of 633 students (14-15 years old) in selected secondary schools in two Philippine provinces. Stool specimens were processed following the Kato-Katz technique and examined for the presence of helminth ova. Overall cumulative prevalence of STH was 31.3%, while prevalence of moderate-heavy-intensity infections was 7.7%, well beyond the WHO target of ≤1% for reducing morbidity in school-age children. Recommendations were made to update the Philippine helminth control program and to re-examine the WHO strategic plan so that helminth prevention and control strategies may also be emphasized for secondary school students especially in high-prevalence areas.

Genetically engineered mouse model of pleomorphic liposarcoma: Immunophenotyping and histologic characterization.

INTRODUCTION: Pleomorphic liposarcoma is a rare and aggressive subset of soft-tissue sarcomas with a high mortality burden. Local treatment largely consists of radiation therapy and wide surgical resection, but options for systemic therapy in the setting of metastatic disease are limited and largely ineffective, prompting exploration of novel therapeutic strategies and experimental models. As with other cancers, sarcoma cell lines and patient-derived xenograft models have been developed and used to characterize these tumors and identify therapeutic targets, but these models have inherent limitations. The establishment of genetically engineered mouse models represents a more realistic framework for reproducing clinically relevant conditions for studying pleomorphic liposarcoma. METHODS: Trp53fl/fl/Rb1fl/fl/Ptenfl/fl (RPP) mice were used to reliably generate an immunocompetent model of mouse pleomorphic liposarcoma through Cre-mediated conditional silencing of the Trp53, Rb1, and Pten tumor suppressor genes. Evaluation of tumor-infiltrating lymphocytes was assessed with immunostaining for CD4, CD8, and PD-L1, and flow cytometry with analysis of CD45, CD3, CD4, CD8, CD19, F4/80, CD11b, and NKp46 sub-populations. RESULTS: Mice reliably produced noticeable soft-tissue tumors in approximately 6 weeks with rapid tumor growth between 100 and 150 days of life, after which mice reached euthanasia criteria. Histologic features were consistent with pleomorphic liposarcoma, including widespread pleomorphic lipoblasts. Immunoprofiling and assessment of tumor-infiltrating lymphocytes was consistent with other soft-tissue sarcomas. CONCLUSION: Genetically engineered RPP mice reliably produced soft-tissue tumors consistent with pleomorphic liposarcoma, which immunological findings similar to other soft-tissue sarcomas. This model may demonstrate utility in testing treatments for this rare disease, including immunomodulatory therapies.

Differentiating infection, colonisation, and sterile inflammation in critical illness: the emerging role of host-response profiling.

Infection results when a pathogen produces host tissue damage and elicits an immune response. Critically ill patients experience immune activation secondary to both sterile and infectious insults, with overlapping clinical phenotypes and underlying immunological mechanisms. Patients also undergo a shift in microbiota with the emergence of pathogen-dominant microbiomes. Whilst the combination of inflammation and microbial shift has long challenged intensivists in the identification of true infection, the advent of highly sensitive molecular diagnostics has further confounded the diagnostic dilemma as the number of microbial detections increases. Given the key role of the host immune response in the development and definition of infection, profiling the host response offers the potential to help unravel the conundrum of distinguishing colonisation and sterile inflammation from true infection. This narrative review provides an overview of current approaches to distinguishing colonisation from infection using routinely available techniques and proposes matrices to support decision-making in this setting. In searching for new tools to better discriminate these states, the review turns to the understanding of the underlying pathobiology of the host response to infection. It then reviews the techniques available to assess this response in a clinically applicable context. It will cover techniques including profiling of transcriptome, protein expression, and immune functional assays, detailing the current state of knowledge in diagnostics along with the challenges and opportunities. The ultimate infection diagnostic tool will likely combine an assessment of both host immune response and sensitive pathogen detection to improve patient management and facilitate antimicrobial stewardship.

Still an Ineffective Method With Supertrials/ERPs-Comments on "Decoding Brain Representations by Multimodal Learning of Neural Activity and Visual Features".

A recent paper claims that a newly proposed method classifies EEG data recorded from subjects viewing ImageNet stimuli better than two prior methods. However, the analysis used to support that claim is based on confounded data. We repeat the analysis on a large new dataset that is free from that confound. Training and testing on aggregated supertrials derived by summing trials demonstrates that the two prior methods achieve statistically significant above-chance accuracy while the newly proposed method does not.

Thermal properties of polymethyl methacrylate vary depending on brand and type.

Polymethyl methacrylate (PMMA) is commonly used in orthopedic surgery and has several applications, most often for fixation of arthroplasty components. While its overall safety and tolerance are well described, less is known regarding the thermal properties of PMMA as it sets from a liquid to solid state, as well as the potential for osseous thermal necrosis. This study addresses potential variations in the setting time and maximum temperature of PMMA formulations in common use and explores the potential clinical implications of this variability. Seven commercially available formulations of PMMA that varied by brand and/or viscosity were obtained and prepared according to manufacturer's instructions. Peak temperature and duration were measured in controlled settings for each type and compared to previously described thresholds for thermal bone necrosis. Depuy SmartSet (HV), Zimmer Palacos R (HV), and Zimmer Palacos (LV) exceeded the 56°C threshold reported to potentially induce immediate osseous thermal necrosis. Additionally, Biomet Cobalt (MV) and Stryker Simplex P (MV) had lower peak temperatures but exceeded thermal necrosis thresholds due to curing duration. The lowest peak temperature was observed for Smith & Nephew Versabond (MV), which was significantly lower than all types except Depuy SmartSet (MV). Setting time was not significantly different among groups. There are significant differences in the thermal properties of PMMA formulations in current use. Selection of specific PMMA formulations represents an additional route of procedural optimization depending on the needs of the treating surgeon.

Yoga as an Adjunct Therapy for Musculoskeletal Pain and Burnout in Orthopedic Surgery: A Trainee's Perspective.

Orthopedic surgeons face significant physical and psychosocial stressors during their training as surgical residents and throughout their career. Aside from occupational hazards intrinsic to the profession, two notable and treatable concerns are musculoskeletal pain and emotional burnout, which have a reported prevalence as high as 97% and 56%, respectively, among orthopedic residents. Management of musculoskeletal pain and burnout is essential for promoting surgeon well being, education, and longevity as well as avoiding medical errors and compromises to patient care. This perspective manuscript describes the occupational challenges faced by orthopedic surgeons and promotes a habitual practice of yoga as an adjunct therapy for managing musculoskeletal pain and emotional burnout, and furthermore, introduces the need to reconsider gendered perceptions surrounding orthopedics and the practice of yoga in a profession largely comprised of men.

Extraskeletal myxoid chondrosarcoma: Clinical features and overall survival.

INTRODUCTION: Extraskeletal myxoid chondrosarcoma is a rare form of soft tissue sarcoma characterized by a unique chromosomal translocation involving the NR4A3 gene on chromosome 9. It is most frequently diagnosed in the proximal extremities of older adult males and is notable for its insidious growth with predilection for local recurrence and metastasis. Currently, extraskeletal myxoid chondrosarcoma is managed with wide resection, with recent investigations supporting the utility of adjuvant radiation and novel chemotherapeutic strategies. METHODOLOGY: A retrospective study was performed with the Surveillance, Epidemiology, and End-Results (SEER) database, which was searched for cases of extraskeletal myxoid chondrosarcoma diagnosed between years 2004 and 2015. Demographic variables were assessed, as well as Collaborative Staging variables including tumor size, metastatic disease, grade, and lymph node involvement. Cases were stratified according to the anatomic site of the primary tumor and were described by therapeutic intervention. A multivariate Cox proportional hazards model evaluated predictive factors for poor survival, and Kaplan-Meier analyses assessed effects of various staging, demographic, and therapeutic variables on overall survival. RESULTS: There were 270 cases of extraskeletal myxoid chondrosarcoma reviewed in this study, which were diagnosed most frequently in the lower limb or hip of older adult males. The 5-year overall survival was 76.5% and was worse on univariate assessment for patients with age > 60, high histologic grade, pelvic location, tumor size > 8.0 cm, metastatic or nodal spread, and in patients without surgical intervention. The Cox regression predicted significantly worse survival for older age, larger tumor size, non-surgical status, and high tumor grade. Metastasis did not significantly predict worse survival on multivariate assessment, and neither chemotherapy nor radiotherapy provided a discernable improvement in survival in this cohort. DISCUSSION AND CONCLUSION: As a rare soft tissue sarcoma, many of the presenting features and survival outcomes of extraskeletal myxoid chondrosarcoma remain poorly defined due to the limited prevalence of this disease. The findings of this study suggest the overall survival may be worse than previously reported, and poor prognostic factors are those associated with worse survival in other soft tissue sarcomas, including high histologic grade, older age, larger tumor size, and lack of wide resection. Radiation and chemotherapy did not demonstrably improve survival for patients with localized or metastatic disease.

Nanostructured Cyclodextrin-Mediated Surface for Capacitive Determination of Cortisol in Multiple Biofluids.

The aim of this work is to develop a reusable polypropylene glycol (PPG):ß-cyclodextrin (ßCD) biosensor for cortisol detection. To achieve the most stable support for ßCD, we developed two PPG surfaces. The first surface is based on a gold surface modified with SAM of 3-mercaptopropionic acid (3MPA), and the second surface is based on a glassy carbon surface grafted with 4-carboxyphenyl diazonium salt. We characterized both surfaces by EIS, XPS, and ATR-FTIR and evaluated the stability and reusability of each surface. We found the GC-carboxyphenyl-PPG:ßCD is stable for at least 1 month. We have also demonstrated the reusability of the surface up to 10 times. In detecting cortisol, we used a nonfaradaic electrochemical impedance capacitive model to interpret the surface confirmation changes. We achieved sensitive detection of cortisol in PBS buffer, urine, and saliva with limit of detection of 2.13, 1.29, and 1.33 nM, respectively.

Visual form of ASL verb signs predicts non-signer judgment of transitivity.

Longstanding cross-linguistic work on event representations in spoken languages have argued for a robust mapping between an event's underlying representation and its syntactic encoding, such that-for example-the agent of an event is most frequently mapped to subject position. In the same vein, sign languages have long been claimed to construct signs that visually represent their meaning, i.e., signs that are iconic. Experimental research on linguistic parameters such as plurality and aspect has recently shown some of them to be visually universal in sign, i.e. recognized by non-signers as well as signers, and have identified specific visual cues that achieve this mapping. However, little is known about what makes action representations in sign language iconic, or whether and how the mapping of underlying event representations to syntactic encoding is visually apparent in the form of a verb sign. To this end, we asked what visual cues non-signers may use in evaluating transitivity (i.e., the number of entities involved in an action). To do this, we correlated non-signer judgments about transitivity of verb signs from American Sign Language (ASL) with phonological characteristics of these signs. We found that non-signers did not accurately guess the transitivity of the signs, but that non-signer transitivity judgments can nevertheless be predicted from the signs' visual characteristics. Further, non-signers cue in on just those features that code event representations across sign languages, despite interpreting them differently. This suggests the existence of visual biases that underlie detection of linguistic categories, such as transitivity, which may uncouple from underlying conceptual representations over time in mature sign languages due to lexicalization processes.

Confounds in the Data-Comments on "Decoding Brain Representations by Multimodal Learning of Neural Activity and Visual Features".

Neuroimaging experiments in general, and EEG experiments in particular, must take care to avoid confounds. A recent TPAMI paper uses data that suffers from a serious previously reported confound. We demonstrate that their new model and analysis methods do not remedy this confound, and therefore that their claims of high accuracy and neuroscience relevance are invalid.

Ewing sarcoma of the pelvis: Clinical features and overall survival.

INTRODUCTION: Primary Ewing Sarcoma of Bone is a malignancy whose treatment requires both systemic chemotherapy and local control through surgical resection and/or radiation. Ewing Sarcoma of the pelvis has been noted to confer a worse prognosis relative to other anatomic sites of Ewing Sarcoma. This study explores the presenting features, treatment modalities for local control, and overall survival of primary Ewing sarcoma of the pelvis in comparison to other commonly affected anatomic sites. METHODS: The National Cancer Institute Surveillance, Epidemiology, and End-Results (SEER) database was used to identify cases of pelvic Ewing sarcoma diagnosed between years 2004 and 2015. Demographic variables including sex, race, and age at diagnosis were described for each case, as well as therapeutic modalities including surgery and radiation. Bone-specific Collaborative Staging variables, including tumor size, tumor extension, and metastasis at diagnosis, were described for the same cohort. Univariate and multivariate assessments were performed for statistical comparison between presenting factors, treatment modalities, and between anatomic locations of presentation. RESULTS: Within the database, 296 patients with Ewing sarcoma of the pelvic bones were available for review, which represented 25.7% of the 1152 cases surveyed across all anatomic sites. In the subset of patients with Ewing Sarcoma of the pelvis, 63.5% were male; the median age of diagnosis was 17 years; extra-compartmental tumor extension was noted in 82.1%; average tumor size was 9.7 cm; and metastasis at diagnosis was noted in 46.1% of the cohort. Only 28.6% of the pelvis sarcoma patients received surgical resection as part or all of their local control treatment, while 67.6% received some form of radiation therapy. When compared to the presenting features of Ewing Sarcoma from other anatomic sites, patients with pelvic tumors had larger tumors at time of diagnosis, higher rates of metastatic disease, and were less likely to undergo surgical intervention. The 2-, 5-, and 10-year overall survival rates for the patients presenting with Ewing Sarcoma of the pelvis was 70.3%, 49.7%, and 41.9%, respectively, which were significantly lower across all time-points than any other anatomic site. DISCUSSION AND CONCLUSION: Ewing Sarcoma of the pelvis is an aggressive malignancy that presents with relatively large tumors and a high rate of metastatic dissemination. Surgical intervention is less frequent when Ewing Sarcoma presents in the pelvis than when it presents in other anatomic locations. These factors may contribute to the worse overall survival of Ewing Sarcoma when compared to the same diagnosis originating in other anatomic sites. Prospective, randomized study is required to determine the true causal effects of these factors on survival.

Presenting features and overall survival of chondrosarcoma of the pelvis.

INTRODUCTION: Chondrosarcoma is the second most common sarcoma of bone. This sarcoma is generally unresponsive to chemotherapy and radiation and is primarily managed through surgical excision. Pelvic chondrosarcoma presents a distinct therapeutic challenge due the complexity of resection, frequent recurrence and metastasis, and high post-operative morbidity. METHODS: The SEER database was queried for pelvic chondrosarcoma diagnosed between 2004 and 2015. Cases were described by age, sex, tumor size, extension, grade, metastasis, and therapeutic intervention. These same variables were assessed for the upper extremities, lower extremities, skull and facial bones, thoracic bones, and vertebral column. RESULTS: In total, 472 cases of pelvic chondrosarcoma were identified, representing 18.4% out of 2571 cases of chondrosarcoma distributed throughout the skeletal system. Among pelvic cases, 288 were male and 184 were female, with a median age of diagnosis of 54. Median tumor size was 96 mm, 64.9% of tumors were considered extracompartmental, and 11.3% of tumors were metastatic at time of diagnosis. The 2, 5, and 10-year survival rates for all cases of primary chondrosarcoma of the pelvis are 76.7%, 61.8%, and 52.2%, respectively. Survival was worse for patients with metastasis, male sex, age >60, tumor size >8 cm, dedifferentiated histology, and no surgical resection. On multivariate assessment high grade and metastasis most significantly predicted worse overall survival. CONCLUSION: Pelvic chondrosarcoma commonly presents with high-risk features including larger tumor size, extracompartmental extension, and metastatic disease at diagnosis, predicting worse overall survival compared to non-pelvic tumors, and were the least amenable to surgical resection.

Osteosarcoma of the Pelvis: Clinical Presentation and Overall Survival.

INTRODUCTION: Osteosarcoma is the most common sarcoma of bone. Pelvic osteosarcoma presents a significant therapeutic challenge due to potential late symptom onset, metastatic dissemination at diagnosis, and inherent difficulties of wide surgical resection secondary to the complex and critical anatomy of the pelvis. The rates of survival are well reported for osteosarcoma of the appendicular skeleton, but specific details regarding presentation and survival are less known for osteosarcoma of the pelvis. METHODS: The Surveillance, Epidemiology, and End Results (SEER) program was queried for primary osteosarcoma of the bony pelvis from 2004 to 2015. Cases with Collaborative Staging variables (available after 2004) were analyzed by grade, histologic subtype, surgical intervention, tumor size, tumor extension, and presence of metastasis at diagnosis. The 2-, 5-, and 10-year survival rates were assessed with respect to these variables. The SEER database was then queried for age, tumor size, surgical intervention, metastasis at time of presentation, and survivorship data for patients with primary osteosarcoma of the upper extremity, lower extremity, vertebrae, thorax, and face/skull, and rates for all anatomic locations were then compared to patients with primary pelvic osteosarcoma. RESULTS: A total of 292 cases of pelvic osteosarcoma were identified from 2004 to 2015 within the database, representing 9.8% of cases among all surveyed primary sites. The most common histologic subtype was osteoblastic osteosarcoma (69.9%), followed by chondroblastic osteosarcoma (22.3%). The majority of cases were high-grade tumors (94.3%), of size >8 cm (72.0%), and with extension beyond the originating bone (74.0%). For the entire pelvic osteosarcoma group, the 2-, 5-, 10-year survival rates were 45.6%, 26.5%, and 21.4%, respectively, which were the poorest among surveyed anatomic sites. The 5-year overall survival was an abysmal 5.3% for patients with metastatic disease at diagnosis, and 37.0% for non-metastatic pelvic osteosarcoma treated with surgery and chemotherapy. When compared to other locations, pelvic osteosarcoma had higher rates of metastatic disease at presentation (33.5%), larger median tumor size (11.0 cm), and older median age at diagnosis (47.5 years). While over 85% of patients with tumors at the extremities received surgery, only 47.4% of pelvic osteosarcomas in this cohort received surgical resection-likely influenced by larger tumor size, sacral involvement, frequency of metastasis, older age, or delayed referral to a sarcoma center. CONCLUSION: This study clarifies presenting features and clinical outcomes of pelvic osteosarcomas, which often present with large, high-grade tumors with extracompartmental extension, high likelihood of metastatic disease at diagnosis, and a potential limited ability to be addressed surgically. The survival rates of primary osteosarcoma of the pelvis are poor and are lower than osteosarcomas from other anatomic locations. While acknowledging the influence of metastasis, tumor characteristics, and advanced age on the decision to undergo surgical excision of a pelvic osteosarcoma, the rates of surgical resection are low and highlight the importance of understanding appropriate conditions for oncologic resection of pelvic sarcomas.

Perspective on Nanofiber Electrochemical Sensors: Design of Relative Selectivity Experiments.

The use of nanofibers creates the ability for non-enzymatic sensing in various applications and greatly improves the sensitivity, speed, and accuracy of electrochemical sensors for a wide variety of analytes. The high surface area to volume ratio of the fibers as well as their high porosity, even when compared to other common nanostructures, allows for enhanced electrocatalytic, adsorptive, and analyte-specific recognition mechanisms. Nanofibers have the potential to rival and replace materials used in electrochemical sensing. As more types of nanofibers are developed and tested for new applications, more consistent and refined selectivity experiments are needed. We applied this idea in a review of interferant control experiments and real sample analyses. The goal of this review is to provide guidelines for acceptable nanofiber sensor selectivity experiments with considerations for electrocatalytic, adsorptive, and analyte-specific recognition mechanisms. The intended presented review and guidelines will be of particular use to junior researchers designing their first control experiments, but could be used as a reference for anyone designing selectivity experiments for non-enzymatic sensors including nanofibers. We indicate the importance of testing both interferants in complex media and mechanistic interferants in the selectivity analysis of newly developed nanofiber sensor surfaces.

Reusable Cyclodextrin-Based Electrochemical Platform for Detection of trans-Resveratrol.

A reusable sensor architecture, through the combination of self-assembled monolayers and cyclodextrin supramolecular interactions, is demonstrated for class recognition of hydrophobic analytes demonstrated with trans-resveratrol. The reloadable sensor is based on reversible immobilization of α-cyclodextrin on polyethylene glycol surface. α-cyclodextrins complexes with polyethylene glycols and causes the polymer chains to change their surface configuration. The reproducibility and stability of the sur-face, in the detection of nanomolar concentrations of trans-resveratrol, can be demonstrated by electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and Attenuated total reflectance-Fourier transform infrared spectroscopy. We propose that during sensor operation, α-cyclodextrin decouples from the poly-ethylene glycol surface to complex with trans-resveratrol in solution, and after use, the surface regeneration is conducted with a simple α-cyclodextrin soak. To test the nonspecific response, the sensor was also tested with trans-resveratrol spiked human urine.

The Perils and Pitfalls of Block Design for EEG Classification Experiments.

A recent paper [31] claims to classify brain processing evoked in subjects watching ImageNet stimuli as measured with EEG and to employ a representation derived from this processing to construct a novel object classifier. That paper, together with a series of subsequent papers [11, 18, 20, 24, 25, 30, 34], claims to achieve successful results on a wide variety of computer-vision tasks, including object classification, transfer learning, and generation of images depicting human perception and thought using brain-derived representations measured through EEG. Our novel experiments and analyses demonstrate that their results crucially depend on the block design that they employ, where all stimuli of a given class are presented together, and fail with a rapid-event design, where stimuli of different classes are randomly intermixed. The block design leads to classification of arbitrary brain states based on block-level temporal correlations that are known to exist in all EEG data, rather than stimulus-related activity. Because every trial in their test sets comes from the same block as many trials in the corresponding training sets, their block design thus leads to classifying arbitrary temporal artifacts of the data instead of stimulus-related activity. This invalidates all subsequent analyses performed on this data in multiple published papers and calls into question all of the reported results. We further show that a novel object classifier constructed with a random codebook performs as well as or better than a novel object classifier constructed with the representation extracted from EEG data, suggesting that the performance of their classifier constructed with a representation extracted from EEG data does not benefit from the brain-derived representation. Together, our results illustrate the far-reaching implications of the temporal autocorrelations that exist in all neuroimaging data for classification experiments. Further, our results calibrate the underlying difficulty of the tasks involved and caution against overly optimistic, but incorrect, claims to the contrary.