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Most epithelium tissues continuously undergo self-renewal through proliferation and differentiation of epithelial stem cells (known as homeostasis), within a specialized stem cell niche. In highly innervated epithelium, peripheral nerves compose perineural niche and support stem cell homeostasis by releasing a variety of neurotransmitters, hormones, and growth factors and supplying trophic factors to the stem cells. Emerging evidence has shown that both sensory and motor nerves can regulate the fate of epithelial stem cells, thus influencing epithelium homeostasis. Understanding the mechanism of crosstalk between epithelial stem cells and neurons will reveal the important role of the perineural niche in physiological and pathological conditions. Herein, we review recent discoveries of the perineural niche in epithelium mainly in tissue homeostasis, with a limited touch in wound repair and pathogenesis.

The objective of this study was to investigate the effects of chronic administration of caffeine on the anatomical characteristics of taste buds, the expression level of taste receptor protein in mice, and preference for a palatable solution. We found that following a 21-day administration of caffeine, mice showed increased behavioural responses to sweet stimuli (acesulfame-K solution). Mirroring this behavioural change, chronic caffeine treatment evidently decreased the maximal cross-sectional area and height of the longitudinal axis of fungiform taste buds, the number of taste cells per fungiform taste bud, and the expression of G protein α-gustducin, while the expression of the sweet taste receptors T1R2 and T1R3 was reversed. Our findings demonstrate that chronic administration of caffeine has an impact on taste sensitivity and changes in taste bud features, which may contribute to the alteration of taste behaviour.

This study's aim is to establish a new sensory sweetness definition and conversion method for five sugars. A "closed-type" question based on triangle test and paired comparison was used for sensory evaluation. The absolute threshold and nine sensory difference threshold values were determined and used to generate a sweet sensory difference strength curve. Defining absolute threshold of sucrose sweetness as 1, the sucrose sweetness at any concentration could be calculated via the curve. After taking the logarithm of each curve, sweetness index was calculated as 1, 1.12, 0.94, 1.29, and 1.25 for sucrose, glucose, fructose, lactose and maltose, respectively. Based on this, each sugar concentration and sweetness could be converted and calculated. Single sugar and mixed-sugars sweetness comparison experiments verified the new sweetness index and sweetness values were more accurate (83.3-100%) than those reported in previous studies. Therefore, this new definition and conversion method established more reliable references for sweet taste sensory applications.

A high-performance TiO2 nanowire photocatalyst was successfully prepared by a hydrothermal method to decompose gaseous formaldehyde into CO2 and H2O in a homemade tube reactor without secondary pol...

Core–shell g-C3N4/Pt/TiO2 nanowire structures were successfully synthesized through a facile two-step synthetic methodology, involving photodepositing Pt nanoparticles on the surface of TiO2 nanowires and subsequent growth of g-C3N4 (CN) layers via thermal evaporation of urea. The as-prepared CN/Pt/TiO2 composites show a higher photocurrent density compared to CN/TiO2. The CN/Pt/TiO2 photocatalysts exhibit an enhanced H2 evolution rate of 8.93 μmol h−1 under visible light irradiation, which is 1.25 times higher than that of CN/TiO2 (7.15 μmol h−1), while Pt/TiO2 and TiO2 nanowires do not show any visible light responses. Our experiments demonstrate for the first time that CN/Pt/TiO2 with a unique core–shell nanowire structure of semiconductor–metal–semiconductor enables concurrent hydrogen evolution through photo-induced water splitting and RhB degradation by photo-oxidation in the visible range. This result is probably attributable to the formation of a heterojunction and the Pt nanoclusters in CN/Pt/TiO2, facilitating the electron transfer from the LUMO of g-C3N4 to that of TiO2 and generating different active sites upon photo-absorption in the CN layers. Our work provides a feasible way to obtain H2 while treating sewage using photocatalysis.

BACKGROUND Sour taste perception builds on both chemical and physiological foundations, and plays an important role in food flavor, including that of fruit, beer, wine, and other beverages. A uniform sourness standard and sourness conversion method for researchers and food enterprises is necessary to obtain uniform conclusions. RESULTS This study established an optimized organic acid sensory sourness analysis and sourness conversion method. It is based on sour sensory difference strength curves, which consist of an absolute threshold value and sensory difference threshold values. Defining the absolute threshold value of citric acid sourness as 1, sourness could be calculated according to the curve. With a logarithmic curve form, the acid sourness indexes (AI) were calculated as 1, 0.74, 0.77, 1.31, and 1.21 for citric, malic, fumaric, lactic, and tartaric acid samples, respectively. Consequently, each acid's sourness and concentration could be obtained and converted. Single acid and mixed acid sourness comparison evaluation's result implied that the novel method was more accurate (91.7-100%) than the hydrogen ion concentration method. CONCLUSION The novel sourness determination and conversion equation would provide more accurate sourness standard and calculation method in food sensory areas. © 2021 Society of Chemical Industry.

In recent years, the safety of copper in drinking water has increasingly been questioned. Copper speciation is an important factor that affects its bioavailability and toxicity; thus, it is critical to investigate the speciation of copper that is ingested from food and drinking water during in vitro digestion. After digestion, water- and food-derived copper formed 60 ± 4% 0.1–1 kDa and 49 ± 6% 10–1,000 kDa copper complexes, respectively. Under simulated fasting drinking water conditions, up to 90 ± 2% 0.1–1 kDa copper complexes formed. In addition, using ion selective electrode analysis, water-derived copper was detected that contained higher Cu2+ concentrations after digestion than those of food-derived copper. These results indicate that water-derived copper forms smaller-sized species and exhibits higher Cu2+ concentrations during digestion than those of food-derived copper, thereby highlighting the importance of reassessing the safety limit for copper in drinking water.

A broad-spectrum sweet taste sensor based on Ni(OH)2/Ni electrode was fabricated by the cyclic voltammetry technique. This sensor can be directly used to detect natural sweet substances in 0.1 M NaOH solution by chronoamperometry method. The current value measured by the sensor shows a linear relationship with the concentration of glucose, sucrose, fructose, maltose, lactose, xylitol, sorbitol, and erythritol (R2 = 0.998, 0.983, 0.999, 0.989, 0.985, 0.990, 0.991, and 0.985, respectively). Moreover, the characteristic value of this sensor is well correlated with the concentration and relative sweetness of eight sweet substances. The good correlation between the characteristic value of six fruit samples measured by the sensor and human sensory sweetness measured by sensory evaluation (correlation coefficient = 0.95) indicates that it can reflect the sweetness of fruits containing several sweet substances. In addition, the sensor also exhibits good long-term stability over 40 days (signal ratio fluctuation ranges from 91.5% to 116.2%). Thus, this broad-spectrum sensor is promising for sweet taste sensory application.