Recent advances and trends in innovative biosensor-based devices for heavy metal ion detection in food.

Low-cost, reliable, and efficient biosensors are crucial in detecting residual heavy metal ions (HMIs) in food products. At present, based on distance-induced localized surface plasmon resonance of noble metal nanoparticles, enzyme-mimetic reaction of nanozymes, and chelation reaction of metal chelators, the constructed optical sensors have attracted wide attention in HMIs detection. Besides, based on the enrichment and signal amplification strategy of nanomaterials on HMIs and the construction of electrochemical aptamer sensing platforms, the developed electrochemical biosensors have overcome the plague of low sensitivity, poor selectivity, and the inability of multiplexed detection in the optical strategy. Moreover, along with an in-depth discussion of these different types of biosensors, a detailed overview of the design and application of innovative devices based on these sensing principles was provided, including microfluidic systems, hydrogel-based platforms, and test strip technologies. Finally, the challenges that hinder commercial application have also been mentioned. Overall, this review aims to establish a theoretical foundation for developing accurate and reliable sensing technologies and devices for HMIs, thereby promoting the widespread application of biosensors in the detection of HMIs in food.

Reconfigurable coaxial single-photon LIDAR based on the SPAD array.

The single-photon avalanche diode (SPAD) array with time-to-digital converter (TDC) circuits on each pixel is an excellent candidate detector for imaging LIDAR systems. However, the low fill-factor of the SPAD array does not allow for efficient use of laser energy when directly adopted in a LIDAR system. Here, we design a reconfigurable coaxial single-photon LIDAR based on the SPAD array and diffractive optical elements (DOEs). We use the DOE and beam expander to shape the laser beam into a laser dot matrix. The total divergence angle of the DOE spot beam is strictly matched to the total field of view (FOV) angle of the SPAD array. Meanwhile, each focused beamlet is individually matched to every active area of the SPAD array detector, which increases the use of output energy about 100 times compared to the diffusion illumination system. Besides, the system uses the active area as the minimum pixel and can support sub-pixel scanning, resulting in higher resolution images. Through this coaxial structure, two different telescope systems after transceiver switching can be reconfigured for imaging targets at different distances. Based on our single-photon LIDAR system, we achieved 3D imaging of targets at 100 m and 180 m using two different telescope configurations.

High-resolution depth imaging with a small-scale SPAD array based on the temporal-spatial filter and intensity image guidance.

Currently single-photon avalanche diode (SPAD) arrays suffer from a small-scale pixel count, which makes it difficult to achieve high-resolution 3D imaging directly through themselves. We established a CCD camera-assisted SPAD array depth imaging system. Based on illumination laser lattice generated by a diffractive optical element (DOE), the registration of the low-resolution depth image gathered by SPAD and the high-resolution intensity image gathered by CCD is realized. The intensity information is used to guide the reconstruction of a resolution-enhanced depth image through a proposed method consisting of total generalized variation (TGV) regularization and temporal-spatial (T-S) filtering algorithm. Experimental results show that an increasement of 4 × 4 times for native depth image resolution is achieved and the depth imaging quality is also improved by applying the proposed method.

CITED4 mediates proliferation, apoptosis and steroidogenesis of Hu sheep granulosa cells in vitro.

Being a novel target of luteinizing hormone (LH), the effect of CREB-binding protein/P300-interacting trans-activator with ED-rich tail member 4 (CITED4) gene on the proliferation, apoptosis, and steroidogenesis of ovarian granulosa cells (GCs) in Hu sheep was investigated. The presence of CITED4, CREB-binding protein (CBP), CCAAT/enhancer-binding protein alpha (C/EBPα) and -beta (C/EBPß) proteins was demonstrated in GCs and luteal cells. CITED4 protein in GCs was induced by LH, and CITED4 overexpression moderately increased GC responses to LH. In contrast, CITED4 knockdown in GCs decreased prostaglandin (PGE2)-induced LH target gene levels. Moreover, PGE2-stimulated CITED4 mRNA expression was blocked by ERK1/2 inhibition (U0126), suggesting that CITED4 is a downstream target of the ERK1/2 pathway in sheep GCs. In contrast to CITED4 knockdown, CITED4 overexpression promoted GC proliferation, inhibited apoptosis, upregulated cell cycle-related genes, and downregulated apoptosis-related genes. Additionally, CITED4 overexpression induced cell cycle transition from S to G2/M phase. No effect was observed with CITED4 knockdown. CITED4 overexpression increased progesterone (P4) production levels and STAR mRNA expression, whereas CITED4 knockdown decreased P4 production and STAR and 3ß-HSD mRNA expression levels. Thus, our results suggest that CITED4 is involved in regulating the expression of LH-induced genes and the ERK1/2 pathway and the proliferation, apoptosis, and steroidogenesis in Hu sheep GCs by modulating the expression of related genes. These findings will help understand the role of CITED4 in follicular development and ovulation of pre-ovulatory follicles.

Hourglass-Type Polyoxometalate-Based Crystalline Material as an Efficient Proton-Conducting Solid Electrolyte.

Proton exchange membrane fuel cells are limited because they are limited to working temperatures and are susceptible to damage by dramatic electrochemical environments such as hydrogen peroxide/radicals. It is necessary to develop new proton-conducting materials that are water-stable and can operate at high temperatures. The hourglass reduced molybdophosphate-based compound (H2bimb)3[Zn3(H6P4Mo6O31)2] (bimb = 1,4-bis[(1H-imidazol-1-yl)methyl]benzene) was designed and synthesized under solvothermal conditions. Single-crystal X-ray diffraction analyses demonstrated noticeably that CUST-571 was composed of an hourglass {Zn[P4Mo6]2} structure, which consisted of two fully reduced half-units {P4Mo6}. It was found that CUST-571 possessed an excellent proton conductivity of 4.54 × 10-3 S cm-1 at 85 °C and 98% RH (relative humidity). In addition, CUST-571 is capable of an excellent catalytic decomposition of H2O2, which is beneficial to increase the life of fuel cells. On the basis of the aforementioned results, CUST-571 may be a promising proton-conducting polyoxometalate hybrid material in the future.

Privacy-Preserved Fall Detection Method with Three-Dimensional Convolutional Neural Network Using Low-Resolution Infrared Array Sensor.

Due to the rapid aging of the population in recent years, the number of elderly people in hospitals and nursing homes is increasing, which results in a shortage of staff. Therefore, the situation of elderly citizens requires real-time attention, especially when dangerous situations such as falls occur. If staff cannot find and deal with them promptly, it might become a serious problem. For such a situation, many kinds of human motion detection systems have been in development, many of which are based on portable devices attached to a user's body or external sensing devices such as cameras. However, portable devices can be inconvenient for users, while optical cameras are affected by lighting conditions and face privacy issues. In this study, a human motion detection system using a low-resolution infrared array sensor was developed to protect the safety and privacy of people who need to be cared for in hospitals and nursing homes. The proposed system can overcome the above limitations and have a wide range of application. The system can detect eight kinds of motions, of which falling is the most dangerous, by using a three-dimensional convolutional neural network. As a result of experiments of 16 participants and cross-validations of fall detection, the proposed method could achieve 98.8% and 94.9% of accuracy and F1-measure, respectively. They were 1% and 3.6% higher than those of a long short-term memory network, and show feasibility of real-time practical application.

Effect of PPARGC1A on the development and metabolism of early rabbit embryos in vitro.

Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A) is a central regulator of mitochondrial biogenesis and metabolism, and its expression is closely related to embryo development. To gain insights into the possible mechanisms of PPARGC1A during early embryogenesis, the development potential, mitochondrial biogenesis, and the culture medium metabolomics of embryos were evaluated when PPARGC1A overexpressed or suppressed in rabbit zygotes. Results showed that different PPARGC1A levels in rabbit zygotes could affect blastocyst percentage, and the expressions of mitochondrial biogenesis and metabolic-related genes, as well as the glutathione and adenosine triphosphate levels during early embryo development. In addition, compared with the controls, 12 and 10 different metabolites involved in carbohydrate, amino acid, and fatty acid metabolism were screened in the 5 day's spent culture medium of PPARGC1A overexpressed and suppressed embryos by gas chromatography-mass spectrometer, respectively. Consistent with these metabolite changes, the transcriptions of genes encoding glucose transporters and fatty acid biosynthetic proteins in the embryos from different groups were regulated by PPARGC1A during rabbit embryo development. Taken together, these data provide evidence that PPARGC1A may regulate early rabbit embryo development through mitochondrial biogenesis and metabolism.

Do the toll-like receptors and complement systems play equally important roles in freshwater adapted Dolly Varden char (Salvelinus malma)?

Unlike the normal anadromous lifestyle, Chinese native Dolly Varden char (Salvelinus malma) is locked in land and lives in fresh water lifetime. To explore the effect of freshwater adaption on its immune system, we constructed a pooled cDNA library of hepatopancreas and spleen of Chinese freshwater Dolly Varden char (S. malma). A total of 27,829 unigenes were generated from 31,233 high-quality transcripts and 17,670 complete open reading frames (ORF) were identified. Totally 25,809 unigenes were successfully annotated and it classified more native than adaptive immunity-associated genes, and more genes involved in toll-like receptor signal pathway than those in complement and coagulation cascades (51 vs 3), implying the relative more important role of toll-like receptors than the complement system under bacterial injection for the freshwater Dolly Varden char. These huge different numbers of TLR and complement system identified in freshwater Dolly Varden char probably caused by distinct evolution pressure patterns between fish TLR and complement system, representative by TLR3 and TLR5 as well as C4 and C6, respectively, which were under purifying and positively selecting pressure, respectively. Further seawater adaptation experiment and the comparison study with our library will no doubt be helpful to elucidate the effect of freshwater adaption of Chinese native Dolly Varden char on its immune system.

Nonadride and Spirocyclic Anhydride Derivatives from the Plant Endophytic Fungus Talaromyces purpurogenus.

Six new nonadride derivatives (1-6) and three new spirocyclic anhydride derivatives (7-9) were isolated from the endophytic fungus Talaromyces purpurogenus obtained from fresh leaves of the toxic medicinal plant Tylophora ovata. The structures of these compounds were determined by spectroscopic analyses including 1D and 2D NMR, HRESIMS, and ECD techniques. Maleic anhydride derivatives 1-9 were evaluated for their in vitro anti-inflammatory activities. Compound 1 showed significant inhibitory activity against NO production in LPS-induced RAW264.7 cells with an IC50 value of 1.9 µM. Compounds 2 and 6 showed moderate inhibitory activities toward XOD and PTP1b, respectively, at 10 µM with inhibition rates of 67% and 76%.

Modulation of lipid metabolism in juvenile yellow catfish (Pelteobagrus fulvidraco) as affected by feeding frequency and environmental ammonia.

In the intensive culture systems, excessive feeding leads to ammonia accumulation, which results in lipid metabolism disorder. However, little information is available on the modulation of lipid metabolism in fish as affected by feeding frequency and ammonia stress. In this study, weight gain increased as feeding frequency increased from one to four times daily, but feed conversion ratio is opposite. The highest survival was found in ammonia group when fish was fed two times daily. Liver ammonia content increased as feeding frequency increased from one to four times daily, and the highest brain ammonia content was found when fish was fed four times daily. The highest liver 6-phospho-gluconate dehydrogenase (6PGD), fatty acid synthase (FAS), carnitine palmitoyltransferase (CPT), and lipoprotein lipase (LPL) contents were found in control group when fish was fed four times daily; in comparison, the highest liver 6PGD, FAS, CPT, and LPL contents were found in ammonia group when fish was fed two times daily. Liver 6PGD, FAS, CPT 1, SREBP-1, and PPARα mRNA expression in control group increased significantly as feeding frequency increased from one to four times daily, and the highest expression of 6PGD, G6PD, and FAS was observed in ammonia group when fish was fed two times daily. This study indicated that the optimal feeding frequency is two times daily when yellow catfish exposed to ammonia.

Endothelial Cells Promote Calcification in Aortic Smooth Muscle Cells from Spontaneously Hypertensive Rats.

BACKGROUND/AIMS: Vascular calcification and hypertension are intimately linked, and the progression of hypertension is closely correlated with endothelial dysfunction. However, the role of endothelial cells (ECs) in vascular calcification of hypertension remains unclear. Therefore, the present study explored the effects of ECs on calcification of smooth muscle cells (SMCs) from aortas of spontaneously hypertensive rats (SHR). METHODS: Aortic ECs and SMCs were isolated from SHR and Wistar rats, respectively. The roles of ECs in the regulation of SMCs calcification were investigated by co-culture and conditioned culture model. Calcium deposition of SMCs was detected by von Kossa staining. Quantization of calcium content in SMCs was determined colorimetrically by the o-cresolphthalein complexone method. Alkaline phosphatase (ALP) activity was measured colorimetrically by p-nitrophenol. The expression levels of MMP-2, MMP-9 and the calcification-promoting proteins were analyzed by Western blot. RESULTS: Calcium deposition, ALP activity and the expression levels of calcification-promoting proteins in SMCs of SHR were significantly higher than that cultured without ECs after 6 days of co-culture with ECs or conditioned culture with the medium of ECs, however, there were no statistical differences between SMCs of Wistar rats. MMP-2 and MMP-9 in co-cultured ECs from SHR were dramatically higher than that cultured without SMCs, nevertheless, there were no statistical differences between ECs from Wistar rats and between SMCs from SHR or Wistar rats. Moreover, SB-3CT, a specific inhibitor of gelatinases, decreased calcium content and the expression levels of calcification-promoting proteins in both co-cultured and conditionally cultured SMCs from SHR. CONCLUSION: ECs have the ability to promote calcification of aortic SMCs of SHR, and elevated expressions of MMP-2 and MMP-9 in ECs of SHR might facilitate the calcification of SMCs.

Growth, blood health, antioxidant status and immune response in juvenile yellow catfish Pelteobagrus fulvidraco exposed to α-ethinylestradiol (EE2).

Triplicate groups of juvenile yellow catfish Pelteobagrus fulvidraco were exposed to three levels of α-ethinylestradiol (EE2) (0, 0.1 and 1 ng L-1) for 56 days. Fish survival rate (>93.33%) was not different among experimental groups. Weight gain and specific growth rate of fish exposed to EE2 were higher than those of control fish. Hepatosomatic index of fish exposed to 1 ng L-1 EE2 was the highest. Serum total protein, albumin, globulin, alanine aminotransferase, aspartate transaminase, cholesterol and triglyceride increased with increasing EE2 exposure levels. Liver total anti-oxidative capacity, malondialdehyde content and lysozyme activity of fish exposed to EE2 were higher than those of control fish. Phagocytic indices of fish exposed to 1 ng L-1 EE2 was lower than that of control fish. This study indicates that although EE2 exposure can promote the growth of yellow catfish in short-term, EE2 exerts its toxic effects by inducing reactive oxygen species generation and malondialdehyde accumulation, leading to blood deterioration and interfering with immune response.

REMEDIAL APPLICATIONS OF EXOSOMES IN CANCER, INFECTIONS AND DIABETES.

Different cell types under normal and diseased states constantly secrete numerous membrane vesicles including exosomes into extracellular space wkich can be isolated from various biological fluids and cell culture supernatants. Exosomal diameter ranges between 40-100 nm. In current research, exosomes are being exploited as biomarkers for pathological diagnosis and potential remedy against various disease conditions such as infections and autoimmune disorders. In cancer immunotherapy, exosomes have promisingly been employed due to the identical immunogenic antigens of exosomes produced by neoplastic cells and the originating tissues. Antigen-specific T-cell activation and immunomodulatory activity is observed to be performed by exosomes isolated from tumor and dendritic cells (DCs). However, more research is still required to uncover the realistic uses of exosomes, particularly as drug delivery tool in autoimmune diseases, cancers and diabetes.

Gelatinases promote calcification of vascular smooth muscle cells by up-regulating bone morphogenetic protein-2.

Matrix metalloproteinase-2 (MMP-2), also known as gelatinase A, is involved in vascular calcification. Another member of gelatinases is MMP-9 (gelatinase B). However, the role of gelatinases in the pathogenesis of vascular calcification is not well understood. The current study aims to clarify the relationship between gelatinases and vascular calcification and to elucidate the underlying mechanism. Beta-glycerophosphate (ß-GP) was used to induce calcification of vascular smooth muscle cells (VSMCs) with or without 2-[[(4-Phenoxyphenyl)sulfonyl]methyl]-thiirane (SB-3CT), a specific gelatinases inhibitor. Levels of calcification were determined by assessing calcium content and calcification area of VSMCs. Phenotype transition of VSMCs was observed by assessing expressions of alkaline phosphatase (ALP), smooth muscle α-actin (SM-α-actin) and desmin. Gelatin zymography was applied to determine the activities of gelatinases, and western blot was applied to determine expressions of gelatinases, bone morphogenetic protein-2 (BMP-2), Runt-related transcription factor 2 (RUNX2) and msh homeobox homolog 2 (Msx-2). Gelatinases inhibition by SB-3CT alleviated calcification and phenotype transition of VSMCs induced by ß-GP. Increased gelatinases expression and active MMP-2 were observed in calcifying VSMCs. Gelatinases inhibition reduced expression of RUNX2, Msx-2 and BMP-2. BMP-2 treatment increased expressions of RUNX2 and Msx-2, while noggin, an antagonist of BMP-2, decreased expressions of RUNX2 and Msx-2. Gelatinases promote vascular calcification by upregulating BMP-2 which induces expression of RUNX2 and Msx-2, two proteins associated with phenotype transition of VSMCs in vascular calcification. Interventions targeting gelatinases inhibition might be a proper candidate for ameliorating vascular calcification.

The protective effects of taurine on acute ammonia toxicity in grass carp Ctenopharynodon idellus.

The four experimental groups were carried out to test the response of grass carp Ctenopharyngodon idella to ammonia toxicity and taurine: group 1 was injected with NaCl, group 2 was injected with ammonium acetate, group 3 was injected with ammonium acetate and taurine, and group 4 was injected taurine. Fish in group 2 had the highest ammonia content in the liver and brain, and alanine, arginine, glutamine, glutamate and glycine contents in liver. Brain alanine and glutamate of fish in group 2 were significantly higher than those of fish in group 1. Malondialdehyde content of fish in group 2 was the highest, but superoxide dismutase and glutathione activities were the lowest. Although fish in group 2 had the lowest red cell count and hemoglobin, the highest alkaline phosphatase, complement C3, C4 and total immunoglobulin contents appeared in this group. In addition, superoxide dismutase and glutathione activities, red cell count and hemoglobin of fish in group 3 were significantly higher than those of fish in group 2, but malondialdehyde content is the opposite. This study indicates that ammonia exerts its toxic effects by interfering with amino acid transport, inducing reactive oxygen species generation and malondialdehyde accumulation, leading to blood deterioration and over-activation of immune response. The exogenous taurine could mitigate the adverse effect of high ammonia level on fish physiological disorder.

Dynamic vibrotactile warning signals for frontal collision avoidance: towards the torso versus towards the head.

Three experiments were conducted to assess the effectiveness of dynamic vibrotactile warning signals with different spatial patterns and to compare dynamic towards-torso and towards-head vibrotactile warnings in a simulated driving task. The results revealed that embedding additional stimuli between the participant's hands and waist in the towards-torso cues (Experiment 1) and increasing the spatial distance between adjacent stimuli in the towards-head cues (Experiment 2) did not result in any further benefits in braking response times (BRTs). The triple towards-head cues resulting from the sequential operation of three pairs of stimuli on the torso gave rise to a significant advantage over the static cues; however, it did not outperform the dynamic towards-torso cues with just two pairs of stimuli. Taken together, these results demonstrated the promise of dynamic vibrotactile warnings (especially, the towards-torso warnings) in terms of the future design of more effective rear-end collision warnings. PRACTITIONER SUMMARY: Three experiments assessed the effectiveness of dynamic towards-torso and towards-head vibrotactile warning signals in a simulated driving task. The results demonstrated the promise of dynamic vibrotactile warnings (especially, the towards-torso vibrotactile warnings) in terms of the future design of more effective frontal collision warnings.

Way-finding during a fire emergency: an experimental study in a virtual environment.

The way-finding behaviour and response during a fire emergency in a virtual environment (VE) was experimentally investigated. Forty participants, divided into two groups, were required to find the emergency exit as soon as possible in a virtual hotel building because of a fire escape demand under condition 1 (VE without virtual fire, control group) and condition 2 (VE with virtual fire, treatment group). Compared to the control group, the treatment group induced significantly higher skin conductivity and heart rate, experienced more stress, took longer time to notice the evacuation signs, had quicker visual search and had a longer escape time to find the exit. These results indicated that the treatment condition induced higher physiological and psychological stress, and had influenced the escape behaviour compared to the control group. In practice, fire evacuation education and fire evacuation system design should consider the response characteristics in a fire emergency.

Friction between footwear and floor covered with solid particles under dry and wet conditions.

Solid particles on the floor, both dry and wet, are common but their effects on the friction on the floor were seldom discussed in the literature. In this study, friction measurements were conducted to test the effects of particle size of solid contaminants on the friction coefficient on the floor under footwear, floor, and surface conditions. The results supported the hypothesis that particle size of solids affected the friction coefficient and the effects depended on footwear, floor, and surface conditions. On dry surfaces, solid particles resulted in friction loss when the Neolite footwear pad was used. On the other hand, solid particles provided additional friction when measured with the ethylene vinyl acetate (EVA) footwear pad. On wet surfaces, introducing solid particles made the floors more slip-resistant and such effects depended on particle size. This study provides information for better understanding of the mechanism of slipping when solid contaminants are present.

CH4/NH3 Flame Structure and Extinction Limit under Flame-Flame Interactions.

Ammonia is considered to play an important role in replacing traditional fossil fuels in future energy systems. In the experimental study, CH4/NH3 flame was lit by applying a double-nozzle burner to gain insight into the structure, and the laminar diffusion flame structure, CH*/OH* intensity maximum, and flame size were analyzed by an ICCD camera. In addition, the extinction limit (lower limit) of the CH4/NH3 flame under different conditions was also studied. The results showed that with the increase of burner pitch, the two diffusion flames showed four states of merged flames, merging flames, inclining separated flames, and independent flames in turn. In the process of flame separation, the continuous pitch between merging flames was short. At this point, higher syngas flow could help increase the continuous pitch to keep merging form. The paper investigated the flame structure and found that the flame size would decrease when the NH3 content in the fuel was high. The flame stability also decreased with an increase of the NH3 content in the fuel. These findings provided experimental proof and a theoretical basis for future studies on the stability of CH4/NH3 co-firing.

Lable-free aptamer portable colorimetric smartphone for gliadin detection in food.

For individuals with celiac disease (CD), the current clinical therapy option available is a lifelong gluten-free diet. Therefore, it is essential to swiftly and efficiently detect gluten in foods. A colorimetric sensor has been developed, which operates by regulating the aggregation and dispersion state of AuNPs induced by high concentration NaCl through the specific binding of gliadin and aptamer, thereby achieving rapid detection of gliadin in flour. It is found that the sensor exhibits good linearity in the concentration range of 0.67-10 µM and the LOD (3σ/S) is 12 nM. And it can accurately distinguish various types of free-gliadin samples, with a spiked recovery rate of 85%-122.3%. To make the detection process more convenient, the colorimetric results of the biosensor were translated into RGB color-gamut parameters by a smartphone color-picking program for further analysis. Gliadin can still be accurately quantified with the established smartphone platform, and a correlation coefficient of 0.988 was found. The proposed portable smartphone aptamer colorimetric sensing device has achieved satisfactory results in the rapid detection of gliadin in food.