Chemical composition of walnuts from three regions in China

To reveal the characteristic chemicals of walnuts from different origins, we analyzed fatty acid composition,tocopherols, phytosterols and total phenolic content (TPC) of walnuts from three main producing regions inChina. The results showed that walnuts were rich in polyunsaturated fatty acids, and the ratio of ω-6 to ω-3 fattyacids was close to the recommendation of Chinese Nutrition Society. Moreover, walnuts contain high contents oftocopherols (331.20–414.71 mg/kg), phytosterols (97.17–110.35 mg/100 g) and phenols (38.51–48.08 mg GAE/kg). Significant chemical differences exist among walnuts from three production regions. The highest content ofpolyunsaturated fatty acids was found in walnuts from the northern China, the highest content of tocopherols inwalnuts from southwest China, and the highest contents of phytosterol and TPC in walnuts from northwest China.However, there was no significant difference in the tocopherol, phytosterol and TPC content of walnuts betweenthe Northern China and Northwest China. The above results provide important references for manufacturers andconsumers to select suitable walnut scientifically and reasonably.

Angiotensin I converting enzyme(ACE)inhibitory activity and antihypertensive effects of rice peptides

In this paper,the antihypertension effect of rice peptide(RP)was studied.With spontaneously hypertensive rats(SHR)and Wistar Kyoto(WKY)as the research objects,RP disposable gastric and long-term gastric irrigation experiments were carried out and systolic blood pressure(SBP)was measured.At the end of the long-term gastric irrigation experiment,the content of nitric oxide(NO),angiotensin-converting enzyme(ACE),angiotensin II(Ang II)and renin in the plasma and the activity of ACE were determined.The results showed that RP could reduce systolic pressure of SHR and had time-dose dependence while high-dose RP signifi cantly reduced systolic pressure by 24.6 and 17.2 mm Hg,respectively after a single and long-term gastric irrigation test.RP also could inhibit the activity of ACE and increase the release of NO.These results suggested that the decompression mechanism of RP is likely to be related to the regulation of the renin-angiotensin system(RAS)and NO.

Universal probe with oriented antibody to improve the immunochromatographic assay of lead ions in Procambarus clarkii

Objectives:Based on the information from the random inspection of foods by the China Food and Drug Administration in 2022,the contamin-ation levels of lead ions are high in many edible products.Traditional methods of detecting lead ions cannot meet the requirements of on-site analysis of food due to the need for large equipment.The immunochromatographic assay(iCA)is an effective,rapid,on-site analytical technique for determining lead ions in foods.However,the performance of ICA based on the traditional probe(AuNP-mAb)is limited by ignoring the influ-ence of theantibody orientation.Materials and Methods:In this study,we developed an efficient technology for constructing a universal probe(AuNP-PrA-mAb)based on the oriented immobilization of antibody.The performance of ICA was largely improved due to specific binding of the Fc region of the antibody with recombinant protein A(PrA)on the surface of a gold nanoparticle(AuNP).The ICA based on a universal probe was applied for the qualitative and quantitative detection of lead ions in Procambarus clarki within 30 min.Meanwhile,a simple and fast pretreatment method based on dilute acid extraction was developed forpretreating thePclarkii containing leadions.Results:The visual limit of detection and the scanning limit of quantization of the developed iCA strip for lead ions were O.5 ng/mL and 0.28 ng/mL,respectively.The sensitivity of ICA based on universal probe was 10-fold higher than that of the ICA using traditional probe.Furthermore,the detection results had no obvious difference between the ICA and ICP-MS with t-test statistical method.Conclusions:The developed ICA based on a universal probe presented broad application prospects in detecting contaminants in foods.

Subwavelength imaging and detection using adjustable and movable droplet microlenses

We developed adjustable and movable droplet microlenses consisting of a liquid with a high refractive index.The microlenses were prepared via ultrasonic shaking in deionized water,and the diameter of the microlenses ranged from 1 to 50μm.By stretching the microlenses,the focal length can be adjusted from 13 to 25μm.With the assistance of an optical tweezer,controllable assembly and movement of microlens arrays were also realized.The results showed that an imaging system combined with droplet microlenses could image 80 nm beads under white light illumination.Using the droplet microlenses,fluorescence emission at 550 nm from Cd Se@Zn S quantum dots was efficiently excited and collected.Moreover,Raman scattering signals from a silicon wafer were enhanced by^19 times.The presented droplet microlenses may offer new opportunities for flexible liquid devices in subwavelength imaging and detection.

Lipid droplets as endogenous intracellular microlenses

Using a single biological element as a photonic component with well-defined features has become a new intriguing paradigm in biophotonics.Here we show that endogenous lipid droplets in the mature adipose cells can behave as fully biocompatible microlenses to strengthen the ability of microscopic imaging as well as detecting intra-and extracellular signals.By the assistance of biolenses made of the lipid droplets,enhanced fluorescence imaging of cytoskeleton,lysosomes,and adenoviruses has been achieved.At the same time,we demonstrated that the required excitation power can be reduced by up to 73%.The lipidic microlenses are finely manipulated by optical tweezers in order to address targets and perform their real-time imaging inside the cells.An efficient detecting of fluorescence signal of cancer cells in extracellular fluid was accomplished due to the focusing effect of incident light by the lipid droplets.The lipid droplets acting as endogenous intracellular microlenses open the intriguing route for a multifunctional biocompatible optics tool for biosensing,endoscopic imaging,and single-cell diagnosis.

Determination of perchlorate and its distribution in unhusked rice in China

Perchlorate concentrations in 387 unhusked rice samples from 15 main producing provinces/municipality in China were investigated by high-performance liquid chromatography-tanden mass spectrometry.The results indicated that perchlorate displays a mean level of 17.17μg/kg in un-husked rice samples.Intriguingly,we also found that perchlorate is mainly observed in rice husk among these collected unhusked rice samples,while less observed in rice bran and milled rice.Specifically,the perchlorate levels in rice were found in the husks(73.61%),bran(10.09%),and milled rice(19.52%),respectively.Our results indicated that there is no significantly perchlorate exposure risk in edible milled rice.