Fingerprinting black tea: When spectroscopy meets machine learning a novel workflow for geographical origin identification

Food fraud, along with many challenges to the integrity and sustainability, threatens the prosperity of businesses and society as a whole. Tea is the second most commonly consumed non-alcoholic beverage globally. Challenges to tea authenticity require the development of highly efficient and rapid solutions to improve supply chain transparency. This study has produced an innovative workflow for black tea geographical indications (GI) discrimination based on non-targeted spectroscopic fingerprinting techniques. A total of 360 samples originating from nine GI regions worldwide were analysed by Fourier Transform Infrared (FTIR) and Near Infrared spectroscopy. Machine learning algorithms (k-nearest neighbours and support vector machine models) applied to the test data greatly improved the GI identification achieving 100% accuracy using FTIR. This workflow will provide a low-cost and user-friendly solution for on-site and real-time determination of black tea geographical origin along supply chains.

Advancing Mycotoxin Detection in Food and Feed: Novel Insights from Surface-Enhanced Raman Spectroscopy (SERS)

The implementation of low-cost and rapid technologies for the on-site detection of mycotoxin-contaminated crops is a promising solution to address the growing concerns of the agri-food industry. Recently, there have been significant developments in surface-enhanced Raman spectroscopy (SERS) for the direct detection of mycotoxins in food and feed. This review provides an overview of the most recent advancements in the utilization of SERS through the successful fabrication of novel nanostructured materials. Various bottom-up and top-down approaches have demonstrated their potential in improving sensitivity, while many applications exploit the immobilization of recognition elements and molecular imprinted polymers (MIPs) to enhance specificity and reproducibility in complex matrices. Therefore, the design and fabrication of nanomaterials is of utmost importance and are presented herein. This paper uncovers that limited studies establish detection limits or conduct validation using naturally contaminated samples. One decade on, SERS is still lacking significant progress and there is a disconnect between the technology, the European regulatory limits, and the intended end-user. Ongoing challenges and potential solutions are discussed including nanofabrication, molecular binders, and data analytics. Recommendations to assay design, portability, and substrate stability are made to help improve the potential and feasibility of SERS for future on-site agri-food applications.

Utilization of Hyperspectral Imaging with Chemometrics to Assess Beef Maturity

There is a growing demand from consumers for more assurance in premium food products such as beef and especially steak. The quality of beef steak is primarily dictated by the maturation which ultimately influences its taste and flavor. These enhanced qualities have resulted in steak becoming a premium product that consumers are willing to pay a premium price for. A challenge, however, is analyzing the maturity of beef by traditional analytical techniques. Hyperspectral imaging (HSI) is a methodology that is gaining traction mainly due to miniaturization, improved optics, and software. In this study, HSI was applied to wet aged beef supplied at various stages of maturity, with spectral data generated using a portable hyperspectral camera. Two trials were conducted over a five-month period: (i) proof of principle and (ii) a bespoke sampling trial for the industry. With the support of industry participation, all samples were sourced from a highly reputable UK/Ireland supplier. To enhance data interpretation, the spectral data collected were combined with multivariate analysis. A range of chemometric models were generated using unsupervised and supervised methods to determine the maturity of the beef, and external validation was performed. The external validation showed good accuracy for "unknown samples" tested against the model set and ranged from 74 to 100% for the different stages of maturity (20, 30, and 40 days old). This study demonstrated that HSI can detect different maturity timepoints for beef samples, which could play an important role in solving some of the challenges that the industry faces with ensuring the authenticity of their products. This is the first time that portable HSI has been coupled with chemometric modeling for assessing the maturity of beef, and it can serve as a model for other food authenticity and quality applications.

Directed Assembly of Au Nanostar@Ag Satellite Nanostructures for SERS-Based Sensing of Hg2+ Ions

Embedding Raman reporters within nanosized gaps of metallic nanoparticles is an attractive route for surface-enhanced Raman spectroscopy (SERS) applications, although often this involves complex synthesis procedures that limit their practical use. Herein, we present the tip-selective direct growth of silver satellites surrounding gold nanostars (AuNSt@AgSAT), mediated by a dithiol Raman reporter 1,4-benzenedithiol (BDT). We propose that BDT is embedded within nanogaps which form between the AuNSt tips and the satellites, and plays a key role in mediating the satellite growth. Not only proposing a rationale for the mechanistic growth of the AuNSt@AgSAT, we also demonstrate an example for its use for the detection of Hg²⁺ ions in water. The presence of Hg²⁺ resulted in amalgamation of the AuNSt@AgSAT, which altered both its structural morphology and Raman enhancement properties. This provides a basis for the detection where the Raman intensity of BDT is inversely proportional to the Hg²⁺ concentrations. As a result, Hg²⁺ could be detected at concentrations as low as 0.1 ppb. This paper not only provides important mechanistic insight into the tip-selective direct growth of the anisotropic nanostructure but also proposes its excellent Raman enhancement capability for bioimaging as well as biological and chemical sensing applications.

Interlaboratory Evaluation of Multiple LC-MS/MS Methods and a Commercial ELISA Method for Determination of Tetrodotoxin in Oysters and Mussels

BACKGROUND

Given the recent detection of tetrodotoxin (TTX) in bivalve molluscs but the absence of a full collaborative validation study for TTX determination in a large number of shellfish samples, interlaboratory assessment of method performance was required to better understand current capabilities for accurate and reproducible TTX quantitation using chemical and immunoassay methods.

OBJECTIVE

The aim was to conduct an interlaboratory study with multiple laboratories, using results to assess method performance and acceptability of different TTX testing methods.

METHODS

Homogenous and stable mussel and oyster materials were assessed by participants using a range of published and in-house detection methods to determine mean TTX concentrations. Data were used to calculate recoveries, repeatability, and reproducibility, together with participant acceptability z-scores.

RESULTS

Method performance characteristics were good, showing excellent sensitivity, recovery, and repeatability. Acceptable reproducibility was evidenced by HorRat values for all LC-MS/MS and ELISA methods being less than the 2.0 limit of acceptability. Method differences between the LC-MS/MS participants did not result in statistically different results. Method performance characteristics compared well with previously published single-laboratory validated methods and no statistical difference was found in results returned by ELISA in comparison with LC-MS/MS.

CONCLUSION

The results from this study demonstrate that current LC-MS/MS methods and ELISA are on the whole capable of sensitive, accurate, and reproducible TTX quantitation in shellfish. Further work is recommended to expand the number of laboratories testing ELISA and to standardize an LC-MS/MS protocol to further improve interlaboratory precision.

HIGHLIGHTS

Multiple mass spectrometric methods and a commercial ELISA have been successfully assessed through an interlaboratory study, demonstrating excellent performance.

The potential and applicability of infrared spectroscopic methods for the rapid screening and routine analysis of mycotoxins in food crops

Infrared (IR) spectroscopy is increasingly being used to analyze food crops for quality and safety purposes in a rapid, nondestructive, and eco-friendly manner. The lack of sensitivity and the overlapping absorption characteristics of major sample matrix components, however, often prevent the direct determination of food contaminants at trace levels. By measuring fungal-induced matrix changes with near IR and mid IR spectroscopy as well as hyperspectral imaging, the indirect determination of mycotoxins in food crops has been realized. Recent studies underline that such IR spectroscopic platforms have great potential for the rapid analysis of mycotoxins along the food and feed supply chain. However, there are no published reports on the validation of IR methods according to official regulations, and those publications that demonstrate their applicability in a routine analytical set-up are scarce. Therefore, the purpose of this review is to discuss the current state-of-the-art and the potential of IR spectroscopic methods for the rapid determination of mycotoxins in food crops. The study critically reflects on the applicability and limitations of IR spectroscopy in routine analysis and provides guidance to non-spectroscopists from the food and feed sector considering implementation of IR spectroscopy for rapid mycotoxin screening. Finally, an outlook on trends, possible fields of applications, and different ways of implementation in the food and feed safety area are discussed.

Handheld SERS coupled with QuEChERs for the sensitive analysis of multiple pesticides in basmati rice

Pesticides are a safety issue globally and cause serious concerns for the environment, wildlife and human health. The handheld detection of four pesticide residues widely used in Basmati rice production using surface-enhanced Raman spectroscopy (SERS) is reported. Different SERS substrates were synthesised and their plasmonic and Raman scattering properties evaluated. Using this approach, detection limits for pesticide residues were achieved within the range of 5 ppb-75 ppb, in solvent. Various extraction techniques were assessed to recover pesticide residues from spiked Basmati rice. Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERs) acetate extraction was applied and characteristic spectral data for each pesticide was obtained from the spiked matrix and analysed using handheld-SERS. This approach allowed detection limits within the matrix conditions to be markedly improved, due to the rapid aggregation of nanogold caused by the extraction medium. Thus, detection limits for three out of four pesticides were detectable below the Maximum Residue Limits (MRLs) of 10 ppb in Basmati rice. Furthermore, the multiplexing performance of handheld-SERS was assessed in solvent and matrix conditions. This study highlights the great potential of handheld-SERS for the rapid on-site detection of pesticide residues in rice and other commodities.

Nanozymes in Point-of-Care Diagnosis: An Emerging Futuristic Approach for Biosensing

Nanomaterial-based artificial enzymes (or nanozymes) have attracted great attention in the past few years owing to their capability not only to mimic functionality but also to overcome the inherent drawbacks of the natural enzymes. Numerous advantages of nanozymes such as diverse enzyme-mimicking activities, low cost, high stability, robustness, unique surface chemistry, and ease of surface tunability and biocompatibility have allowed their integration in a wide range of biosensing applications. Several metal, metal oxide, metal-organic framework-based nanozymes have been exploited for the development of biosensing systems, which present the potential for point-of-care analysis. To highlight recent progress in the field, in this review, more than 260 research articles are discussed systematically with suitable recent examples, elucidating the role of nanozymes to reinforce, miniaturize, and improve the performance of point-of-care diagnostics addressing the ASSURED (affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free and deliverable to the end user) criteria formulated by World Health Organization. The review reveals that many biosensing strategies such as electrochemical, colorimetric, fluorescent, and immunological sensors required to achieve the ASSURED standards can be implemented by using enzyme-mimicking activities of nanomaterials as signal producing components. However, basic system functionality is still lacking. Since the enzyme-mimicking properties of the nanomaterials are dictated by their size, shape, composition, surface charge, surface chemistry as well as external parameters such as pH or temperature, these factors play a crucial role in the design and function of nanozyme-based point-of-care diagnostics. Therefore, it requires a deliberate exertion to integrate various parameters for truly ASSURED solutions to be realized. This review also discusses possible limitations and research gaps to provide readers a brief scenario of the emerging role of nanozymes in state-of-the-art POC diagnosis system development for futuristic biosensing applications.

Rotational resonance of nonaxisymmetric magnetic braking in the KSTAR tokamak

One of the important rotational resonances in nonaxisymmetric neoclassical transport has been experimentally validated in the KSTAR tokamak by applying highly nonresonant n=1 magnetic perturbations to rapidly rotating plasmas. These so-called bounce-harmonic resonances are expected to occur in the presence of magnetic braking perturbations when the toroidal rotation is fast enough to resonate with periodic parallel motions of trapped particles. The predicted and observed resonant peak along with the toroidal rotation implies that the toroidal rotation in tokamaks can be controlled naturally in favorable conditions to stability, using nonaxisymmetric magnetic perturbations.

Magnetic diagnostics for equilibrium reconstructions in the presence of nonaxisymmetric eddy current distributions in tokamaks (invited)

The lithium tokamak experiment (LTX) is a modest-sized spherical tokamak (R(0)=0.4 m and a=0.26 m) designed to investigate the low-recycling lithium wall operating regime for magnetically confined plasmas. LTX will reach this regime through a lithium-coated shell internal to the vacuum vessel, conformal to the plasma last-closed-flux surface, and heated to 300-400 °C. This structure is highly conductive and not axisymmetric. The three-dimensional nature of the shell causes the eddy currents and magnetic fields to be three-dimensional as well. In order to analyze the plasma equilibrium in the presence of three-dimensional eddy currents, an extensive array of unique magnetic diagnostics has been implemented. Sensors are designed to survive high temperatures and incidental contact with lithium and provide data on toroidal asymmetries as well as full coverage of the poloidal cross-section. The magnetic array has been utilized to determine the effects of nonaxisymmetric eddy currents and to model the start-up phase of LTX. Measurements from the magnetic array, coupled with two-dimensional field component modeling, have allowed a suitable field null and initial plasma current to be produced. For full magnetic reconstructions, a three-dimensional electromagnetic model of the vacuum vessel and shell is under development.

A functionally distinct member of the DP family of E2F subunits

E2F transcription factors regulate genes involved in cell-cycle progression. In mammalian cells, physiological E2F exists as an E2F/DP heterodimer. Currently, eight E2F and two DP subunits have been characterized. We report here the characterization of a new member of the DP family, DP-4. While DP-4 exhibits certain similarities with members of the DP family, it also possesses a number of significant differences. Thus, DP-4 forms a heterodimer with E2F subunits, binds to the E2F site and associates with pocket proteins including pRb. In contrast to DP-1, however, DP-4/E2F-1 complexes exhibit reduced DNA binding activity. Furthermore, DP-4 interferes with E2F-1-dependent transcription and delays cell-cycle progression. These results highlight an emerging complexity in the DP family of E2F subunits, and suggest that DP-4 may endow E2F heterodimers with distinct transcription properties.

365 THE EFFECT OF ADMINISTERING PROGESTERONE AND ESTRADIOL PRIOR TO eFSH ON THE SUPEROVULATORY RESPONSE OF MARES

eFSH has been used to induce multiple ovulation in cycling mares. However, the response to eFSH is variable. Generally, eFSH is initiated 5 to 7 days after ovulation at a time when the follicular population on the ovaries may be variable. The objective of this study was to determine whether administration of progesterone and estradiol for 10 days prior to eFSH (Bioniche Animal Health, Athens, GA) would enhance the response to eFSH administration. Thirty normal cycling mares were assigned to 1 of 2 groups. Group 1: Control eFSH treatment - mares were examined daily with ultrasonography beginning 5 days after ovulation. Once the follicles in these mares reached 20 to 25 mm in size, eFSH treatment (12.5 mg, i.m.) was administered twice a day. Cloprostenol (Schering-Plough, Union, NJ, USA) treatment (250 �g) was administered on the second day of eFSH treatment. eFSH treatment continued until the majority of the cohort of follicles reached e35 mm. Treatment was stopped and after approximately 36 h hCG (2500 IU, i.v.; Chorulon; Intervet, Millsboro, MD, USA) was administered. Group 2: Injectable progesterone + estradiol (150 mg of progesterone and 10 mg of estradiol; P+E) treatment was initiated in diestrus (5 to 7 days post-ovulation) for 8 mares and in early estrus for 7 mares in this group. Injectable progesterone was continued for 10 days and Cloprostenol (250 �g) was administered on Day 10. Mares were then examined daily with ultrasonography and, once they had acquired 20- to 25-mm follicles, eFSH treatment was initiated. Twice-daily injections of eFSH (12.5 mg, i.m.) were continued until a majority of the cohort of follicles was e35 mm. hCG was administered approximately 36 h later. All mares were inseminated with 1 billion progressively motile spermatozoa from one of two stallions on the day of hCG administration and on the following day with cooled semen (1 billion progressively motile spermatozoa) from the same stallion. Data were analyzed by t-test and Fisher's Exact Test. The number of days of eFSH treatment was similar for the P+E (2) vs. the control (1) group (4.2 � 2.0 vs. 4.9 � 1.3 days, respectively). However, the number of ovulations induced in response to eFSH was greater for mares in the eFSH control (1) group (5.6 � 2.0) than for those in the P+E (2) group (3.0 � 1.9). Embryo recovery per flush was also greater for eFSH control (1) mares (2.7) vs. P+E (2) mares (1.1). Embryo quality was excellent or good for all embryos in both groups. Seventy-three percent of the mares (11 of 15) in both groups gave at least one embryo at each recovery attempt. However, more mares in the eFSH control (1) group gave two or more embryos (60%) compared to those in the P+E (2) group (20%). In summary, treatment of mares with P+E prior to eFSH treatment resulted in fewer ovulations, fewer embryos recovered, and fewer mares providing e2 embryos. Thus, there was no advantage in pretreating mares with P+E prior to eFSH treatment.

Differential regulation of caspase-3 by pharmacological and developmental stimuli as demonstrated using humanised caspase-3 mice

Caspase-3 is a potential therapeutic target for a number of degenerative diseases. However the development of specific caspase-3 inhibitors has been hampered by inter-species differences and the high degree of homology shared by different caspases. To circumvent these issues, we have produced and characterised a humanised caspase-3 mouse line (possessing one copy of the human gene with both copies of the murine gene disrupted) by crossing human caspase-3 transgenic mice with nullizygous caspase-3 knock-out mice. Humanised mice appeared normal and survived to adulthood. Analysis of the human gene revealed that human pro-caspase-3 was expressed in the same tissues as its murine counterpart. However humanised mice retained the hypercellularity of frontal cortex seen in their knock-out parental line and there was no biochemical evidence of human protein processing during naturally occurring neuronal death taking place during brain development. In contrast, the human protein was cleaved by the mouse machinery following anti-Fas treatment of adult mice. These data suggest that there is a fundamental difference between the activation pathways leading to caspase-3 cleavage during naturally occurring cell death in development/embryogenesis and following an apoptotic stimulus in the adult.

Mice overexpressing human caspase 3 appear phenotypically normal but exhibit increased apoptosis and larger lesion volumes in response to transient focal cerebral ischaemia

Caspase 3 activation has been implicated in cell death following a number of neurodegenerative insults. To determine whether caspase genes can affect the susceptibility of cells to neurodegeneration, a transgenic mouse line was created, expressing human caspase 3 under control of its own promoter. The human gene was regulated by the murine homeostatic machinery and human procaspase 3 was expressed in the same tissues as mouse caspase 3. These novel transgenic mice appeared phenotypically and developmentally normal and survived in excess of 2 years. Behavioural assessment using the 5-choice serial reaction time task found no differences from wild-type littermates. Caspase activity was found to be tightly regulated under physiological conditions, however, significantly larger lesions were obtained when transgenic mice were subjected to focal cerebral ischaemia/reperfusion injury compared to wild-type littermates. These data demonstrate that mice overexpressing human caspase 3 are essentially normal, however, they have increased susceptibility to degenerative insults.

Resting heart rate definition and its effect on apparent levels of physical activity in young children

PURPOSE

Heart rate monitoring is widely used to measure physical activity in children, but it may be dependent on the definition of resting heart rate used and the protocol used to measure or derive resting heart rate (RHR). The aim of this study was to determine the effect of RHR definition on activity levels assessed by PAHR-25 (% time at >25% of RHR), PAHR-50 (% time at >50% of RHR), and activity heart rate (AHR; mean HR minus RHR).

METHODS

Minute-to-minute heart rates were measured over 3 d in 20 healthy preschool children aged 3-4 yr. Resting heart rate was measured for 5 min after a 10-min rest and was also derived from the following different but commonly used protocols: 1) mean of lowest heart rate plus all heart rates within three beats; 2) mean of lowest 5; 3) lowest 10; 4) lowest 50. This gave five different definitions of RHR. Differences in RHR and in the derived indices of activity among definitions were tested for agreement using a Bland-Altman analysis, and by rank order correlation.

RESULTS

Differences in RHR among all definitions were statistically significant. These resulted in significant differences in apparent physical activity levels: PAHR-25 varied 10-50% depending on the protocol used to define RHR; PAHR-50 varied by 16-65% as a function of the protocol used to define RHR. However, the different definitions of RHR had no significant influence on physical activity level when children were rank ordered.

CONCLUSION

Choice of method for defining RHR has a profound effect on the apparent level of activity of children. This does not alter the relative assessment of activity by rank order. A consensus definition of RHR is desirable if comparisons of activity levels between samples or populations are to be made and if the adequacy of physical activity levels is to be assessed using heart rate.

Hypnosis in dental education: a survey of U.S. dental schools, 1980

This paper reports the results of a 1980 survey of the teaching of hypnosis in U.S. dental schools. Responses were received from 60 dental schools. Information was obtained on hypnosis education in both the predoctoral and postdoctoral curriculums, including what is being taught, how hypnosis education is structured in the curriculum, who is teaching hypnosis, the number of students receiving hypnosis education, and attitudes and policies about hypnosis education. Results of this survey were compared to previous surveys by Parrish (1973) and Scott (1977, for the United Kingdom). The survey reveals a gradual increase in the number of U.S. dental schools teaching hypnosis.