Dermal Sensory Regenerative Peripheral Nerve Interface for Reestablishing Sensory Nerve Feedback in Peripheral Afferents in the Rat.

BACKGROUND: Without meaningful, intuitive sensory feedback, even the most advanced myoelectric devices require significant cognitive demand to control. The dermal sensory regenerative peripheral nerve interface (DS-RPNI) is a biological interface designed to establish high-fidelity sensory feedback from prosthetic limbs. METHODS: DS-RPNIs were constructed in rats by securing fascicles of residual sensory peripheral nerves into autologous dermal grafts, with the objectives of confirming regeneration of sensory afferents within DS-RPNIs and establishing the reliability of afferent neural response generation with either mechanical or electrical stimulation. RESULTS: Two months after implantation, DS-RPNIs were healthy and displayed well-vascularized dermis with organized axonal collaterals throughout and no evidence of neuroma. Electrophysiologic signals were recorded proximal from DS-RPNI's sural nerve in response to both mechanical and electrical stimuli and compared with (1) full-thickness skin, (2) deepithelialized skin, and (3) transected sural nerves without DS-RPNI. Mechanical indentation of DS-RPNIs evoked compound sensory nerve action potentials (CSNAPs) that were like those evoked during indentation of full-thickness skin. CSNAP firing rates and waveform amplitudes increased in a graded fashion with increased mechanical indentation. Electrical stimuli delivered to DS-RPNIs reliably elicited CSNAPs at low current thresholds, and CSNAPs gradually increased in amplitude with increasing stimulation current. CONCLUSIONS: These findings suggest that afferent nerve fibers successfully reinnervate DS-RPNIs, and that graded stimuli applied to DS-RPNIs produce proximal sensory afferent responses similar to those evoked from normal skin. This confirmation of graded afferent signal transduction through DS-RPNI neural interfaces validate DS-RPNI's potential role of facilitating sensation in human-machine interfacing. CLINICAL RELEVANCE STATEMENT: The DS-RPNI is a novel biotic-abiotic neural interface that allows for transduction of sensory stimuli into neural signals. It is expected to advance the restoration of natural sensation and development of sensorimotor control in prosthetics.

Identifying Risk Factors for Recurrence After Cubital Tunnel Release.

PURPOSE: This study investigated specific risk factors for recurrent surgery of ulnar nerve entrapment (ie, ipsilateral clinical symptoms within 5 years after initial cubital tunnel release [CuTR]) in a large cohort. We hypothesized that recurrence is associated with lifestyle variables (eg, smoking, drinking alcohol, a high body mass index [BMI]) or comorbidities). METHODS: A retrospective cohort study was performed using the Current Procedural Terminology codes for all patients who underwent CuTR between January 2012 and November 2018. Demographic data, including sex, age, weight, height, BMI, comorbidities, smoking, and alcohol consumption, were collected. The primary outcome was the need for revision surgery after initial CuTR. Univariate and multivariate analyses were performed to identify potential risk factors for revision surgery. RESULTS: Of the 678 patients who underwent CuTR, 120 patients (18%) needed revision surgery within 5 years. Sixty-six patients required subfascial transposition (55%) and 47 patients (39%) received in situ releases. Also, sex, BMI, smoking, alcohol consumption, and comorbidities (except for spinal disc herniation) were similar between the primary and revision subgroup. Age at first occurrence was significantly lower in the revision group (48 years for revision vs 52 years for primary surgery). Moreover, cervical spinal disc herniation was associated with revision surgery (13% vs 6% in the primary group). CONCLUSIONS: Age and medical history of cervical spinal disc herniation are associated with an increased risk of revision surgery. More importantly, BMI, smoking, alcohol consumption, and other comorbidities are not associated with increased risk of revision surgery within our sample. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Molecularly imprinted core-shell Au nanoparticles for 2,4-dichlorophenoxyacetic acid detection in milk using surface-enhanced Raman spectroscopy.

Surface-enhanced Raman spectroscopy (SERS) has been extensively investigated for rapid and sensitive detection of trace level chemical contaminants in foods. Lack of selectivity to the targeted molecules in food matrices and fairly poor spectral reproducibility remain the main challenges for practical SERS applications. Herein, an ingenious strategy was proposed to hybridize molecularly imprinted polymers (MIPs) with gold nanoparticles as the functional SERS substrate for selective separation and detection of 2,4-dichlorophenoxyacetic acid (2,4-D), a systemic herbicide that has acute toxicity and potential cancer risk. The core-shell AuNPs@MIPs nanoparticles were finely tailored by wrapping an ultrathin layer of MIPs shell on the surface of AuNPs, which allowed selectively separating and enriching 2,4-D to the near surface of AuNPs and ensured the enhancement of Raman scattering signal of the analyte. Embedding an internal standard (i.e., 4-aminothiophenol) inside AuNPs@MIPs for SERS spectral calibration improved the quantification accuracy for 2,4-D. Three-dimensional finite difference time domain (3D-FDTD) simulation demonstrated the maximal electric field enhancement presented in the gap between adjacent AuNPs@MIPs with the theoretical enhancement factor (EF) as high as 5.85 × 106. Chemometric models established using SERS spectra showed accurate differentiation and quantification results for 2,4-D in milk at various contamination levels with a limit of detection (LOD) of 0.011 µg/mL. Our approach to integrate MIPs with noble metallic nanoparticles has great potential for selective and quantitative detection of analytes using SERS for practical agri-food analysis.

Untargeted volatile metabolomics using comprehensive two-dimensional gas chromatography-mass spectrometry - A solution for orange juice authentication.

Orange juice is one of the most consumed fruit juices worldwide and its adulteration has been a long-lasting concern. In this study, an untargeted volatile metabolomics using a comprehensive two-dimensional gas chromatography-quadrupole mass spectrometry (GC × GC-qMS) was developed to systematically authenticate orange juice. At least 405 citrus whole fruits were collected, belongs to 58 types of orange samples and 23 types of non-orange citrus. The fruit juices were prepared in the laboratory and analyzed using the comprehensive GC × GC-qMS instrument. After optimizing the instrumental settings, this novel method was able to identified ~250 volatiles in each juice sample, covering a variety types of hydrocarbons, esters, alcohols, aldehydes, ketones and others. Combining with unsupervised principal component analysis and supervised partial least squares-discriminant analysis , this novel analytical tool was able to authenticate orange juice from a broad perspectives with a high accuracy in the cross-validation model: 1) differentiating orange juice from non-orange citrus juice (99% accuracy), 2) recognizing orange harvesting years (100% accuracy) and geographical origins (96% accuracy), and 3) distinguishing original pure orange juice from the reconstituted juice (94% accuracy). Key volatile metabolites associated with different categories of samples were also identified after thorough investigation of the loading values of the classification models. These metabolites have high potential to be used as food-markers to design targeted analytical methods for orange juice authentication. This novel comprehensive GC × GC-qMS-based method is ideal for governmental laboratories and the food industry to routinely authenticate orange juice.

Application of nuclear magnetic resonance spectroscopy in food adulteration determination: the example of Sudan dye I in paprika powder.

Carcinogenic Sudan I has been added illegally into spices for an apparent freshness. 1H solution and solid-state (SS) nuclear magnetic resonance (NMR) spectroscopies were applied and compared for determination of Sudan I in paprika powders (PPs). For solution NMR, PPs spiked with Sudan I were extracted with acetonitrile, centrifuged, rotor-evaporated, and re-dissolved in DMSO-d6 for spectral collection. For SSNMR, Sudan I contaminated PPs were mixed with DMSO-d6 solution and used for spectral collection. Linear regression models constructed for quantitative analyses resulted in the average accuracies for unknown samples as 98% and 105%, respectively. Limits of detection for the solution NMR and SSNMR spectrometers were 6.7 and 128.6 mg kg-1, while the limits of quantification were 22.5 and 313.7 mg kg-1. The overall analysis time required by both methods was similar (35 and 32 min). Both NMR techniques are feasible for rapid and accurate determination of Sudan I adulteration in PPs.

Determination of antioxidant capacity and phenolic content of chocolate by attenuated total reflectance-Fourier transformed-infrared spectroscopy.

Antioxidant capacity and phenolic content of chocolate, containing different amounts of cacao (35-100%), were determined using attenuated total reflectance (ATR)-Fourier transformed-infrared (FT-IR) spectroscopy (4000-550cm(-1)). Antioxidant capacities were first characterized using DPPH (2,2-diphenyl-1-picrylhydrazyl) and ORAC (oxygen radical absorbance capacity) assays. Phenolic contents, including total phenol and procyanidins monomers, were quantified using the Folin-Ciocalteu assay and high performance liquid chromatography coupled with photodiode array detector (HPLC-DAD), respectively. Five partial least-squares regression (PLSR) models were constructed and cross-validated using FT-IR spectra from 18 types of chocolate and corresponding reference values determined using DPPH, ORAC, Folin-Ciocalteu, and HPLC assays. The models were validated using seven unknown samples of chocolate. PLSR models showed good prediction capability for DPPH [R(2)-P (prediction)=0.88, RMSEP (root mean squares error of prediction)=12.62µmol Trolox/g DFW], ORAC (R(2)-P=0.90, RMSEP=37.92), Folin-Ciocalteu (R(2)-P=0.88, RMSEP=5.08), and (+)-catechin (R(2)-P=0.86, RMSEP=0.10), but lacked accuracy in the prediction of (-)-epicatechin (R(2)-P=0.72, RMSEP=0.57). ATR-FT-IR spectroscopy can be used for rapid prediction of antioxidant capacity, total phenolic content, and (+)-catechin in chocolate.

Application of Attenuated Total Reflectance-Fourier Transformed Infrared (ATR-FTIR) Spectroscopy To Determine the Chlorogenic Acid Isomer Profile and Antioxidant Capacity of Coffee Beans.

The chlorogenic acid isomer profile and antioxidant activity of both green and roasted coffee beans are reported herein using ATR-FTIR spectroscopy combined with chemometric analyses. High-performance liquid chromatography (HPLC) quantified different chlorogenic acid isomer contents for reference, whereas ORAC, ABTS, and DPPH were used to determine the antioxidant activity of the same coffee bean extracts. FTIR spectral data and reference data of 42 coffee bean samples were processed to build optimized PLSR models, and 18 samples were used for external validation of constructed PLSR models. In total, six PLSR models were constructed for six chlorogenic acid isomers to predict content, with three PLSR models constructed to forecast the free radical scavenging activities, obtained using different chemical assays. In conclusion, FTIR spectroscopy, coupled with PLSR, serves as a reliable, nondestructive, and rapid analytical method to quantify chlorogenic acids and to assess different free radical-scavenging capacities in coffee beans.

Determination of Sudan I in paprika powder by molecularly imprinted polymers-thin layer chromatography-surface enhanced Raman spectroscopic biosensor.

Sudan I is a carcinogenic and mutagenic azo-compound that has been utilized as a common adulterant in spice and spice blends to impart a desirable red color to foods. A novel biosensor combining molecularly imprinted polymers (MIPs), thin layer chromatography (TLC) and surface enhanced Raman spectroscopy (SERS) could determine Sudan I levels in paprika powder to 1 ppm (or 2 ng/spot). Sudan I spiked paprika extracts (spiking levels: 0, 1, 5, 10, 40, 70 and 100 ppm) were prepared. Sudan I imprinted polymers were synthesized by employing the interaction between Sudan I (template) and methacrylic acid (functional monomer), followed by washing to remove Sudan I leaving the Sudan I-binding sites exposed. MIPs were used as a stationary phase for TLC and could selectively retain Sudan I at the original spot with little interference. A gold colloid SERS substrate could enhance Raman intensity for Sudan I in this MIP-TLC system. Principal component analysis plot and partial least squares regression (R(2)=0.978) models were constructed and a linear regression model (R(2)=0.983) correlated spiking levels (5, 10, 40, 70 and 100 ppm) with the peak intensities (721 cm(-1)) of Sudan I SERS spectra. Both separation (30-40s) and detection (1s or 0.1s) were extremely fast by using both commercial bench-top and custom made portable Raman spectrometers. This biosensor can be applied as a rapid, low-cost and reliable tool for screening Sudan I adulteration in foods.

Contraction of abdominal wall muscles influences size and occurrence of incisional hernia.

BACKGROUND: Incisional hernias are a complication in 10% of all open abdominal operations and can result in substantial morbidity. The purpose of this study was to determine whether inhibiting abdominal muscle contraction influences incisional hernia formation during the fascial healing after laparotomy. We hypothesized that decreasing the deformation of the abdominal musculature would decrease the size or occurrence of an incisional hernia. METHODS: Using an established rat model for incisional hernia, a laparotomy through the linea alba was closed with 1 mid-incision, fast-absorbing suture. Three groups were compared: a sham group (sham; n = 6) received no laparotomy, and the saline hernia (SH; n = 6) and Botox hernia (BH; n = 6) groups were treated once with equal volumes of saline or botulinum toxin (Botox, Allergan) before the incomplete laparotomy closure. On postoperative day 14, the abdominal wall was examined for herniation and adhesions, and contractile forces were measured for abdominal wall muscles. RESULTS: No hernias developed in the sham rats. Rostral hernias developed in all SH and BH rats. Caudal hernias developed in all SH rats, but in only 50% of the BH rats. Rostral hernias in the BH group were 35% shorter and 43% narrower compared with those in the SH group (P < .05). The BH group had weaker abdominal muscles compared with the sham and SH groups (P < .05). CONCLUSION: In our rat model, partial paralysis of abdominal muscles decreases the number and size of incisional hernias. These results suggest that contractions of the abdominal wall muscle play a role in the pathophysiology of the formation of incisional hernias.