Aim To apply stochastic resonance algorithm (SRA) to quantitative analysis of weak chromatographic signal, which was embedded in the noise. Methods Based on the theory of stochastic resonance (SR), a simple and effective SRA has been established to improve analytical detection limits of chromatographic analysis, which apply to enhance the signal to noise ratio by the optimization of the parameters and Runge-Kutta method, was established. The method was used to quantitative analysis of phenazopyridine in human plasma by HPLC/UV. Meanwhile this method is compared with HPLC/MS.Results By experimental chromatographic data sets, an excellent quantitative relationship between concentrations of phenazopyridine and their responses had been obtained. The concentration of phenazopyridine in plasma determined by HPLC/UV with SRA and HPLC/MS showed that there was no significant difference (P ＞ 0.05) between the two methods. Conclusion The new method was feasible.

The study aims to screen the ability of the bacteria to metabolize ononin and assess the effect of ononin on the intestinal bacteria. Fresh human fecal sample was obtained from a healthy volunteer, diluted serially in sterile water and sixty-nine different bacterial colonies were picked out ultimately. UPLC-Q-TOF/MS with automated data analysis software (MetaboLynx) was applied to fast analysis of ononin metabolites. Furthermore, an E(max) precision microplate reader was employed to determine the growth situation of Enterococcous sp., Enterobacter sp., Lactobacilli sp., and Bifidobacteria sp. Results indicated that hydrogenation, demethylation, hydroxylation and deglycosylation were the major metabolic pathways of ononin by human intestinal bacteria in vitro. Ononin can inhibit the growth of pathogen such as Enterococcus sp., Enterobacter sp. and can promote the growth of probiotics such as Bifidobacteria sp. and Lactobacilli sp. This study suggested that intestinal bacteria have the metabolic effects of ononin and the biotransformation was completed by different bacteria. And ononin can affect the balance of intestinal flora and the degree of influence varies depending on the bacterial species and the concentration of ononin.

Naringin has been reported to possess a wild range of biological activities. However, the route and metabolites of naringin produced by intestinal bacteria are not well understood. In this paper, different bacteria were isolated from human feces and their abilities to convert naringin to different metabolites were studied. Ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) with automated data analysis software (MetaboLynx) was applied to fast analysis of naringin metabolites. Using MSE and mass defect filter techniques, three metabolites were detected and tentatively identified. The results indicated that acetylation, hydrolyzation and hydrolyzation with hydrogenation were the major metabolic pathways of naringin in vitro. Then, we studied the gene sequence of the 16S rRNA of the bacteria by extraction of genomic DNA of the strain, PCR amplification and clone of the 16S rRNA. The consequence proved that Enterococcus sp.30, Bacillus sp.46, Escherichia sp.54 and Escherichia sp.63 have the peculiar metabolism characteristic of naringin.

Objective:To explore the function of the cya gene and the preliminary mechanism of attenuated strain.Methods:The biological characteristics of cya mutant in acid and alkali resistant,salt resistance,motility,biofilm components,poisonous to the cells of epithelial cell adhesion,invasion were analysis.Results:The mobility capabilities,acid and alkali resistance and salt tolerance of cya mutant were significantly lower than the parent strain;the composition testing revealed that the cya mutant did not produce cellulose,curli and biofilm;at the same time the adhesion and invasion to epithelial cells of cya mutant had a prominent depression,and the toxicity to HeLa cells was weaker than the parent strain.Conclusion:The function of cya gene is closely related to athletic ability, penetration of cell membrane, the formation biofilm and virulence.It will provide a theory reference to the functional research of Salmonella typhimurium cya gene and the mechanism of attenuated strain.This will contribute to the development of oral vaccine using attenuated Salmonella typhimurium as vector.

In order to evaluate the effect and mechanism of the mulberry leaf alkaloid, flavones, and polysaccharide intervention on diabetes, the overall metabolite profiling characteristics for the plasma of diabetic mouse was performed by using an ultra-performance liquid chromatography/electrospray-tandem mass spectrometry (UPLC-ESI-MS). The 8 potential biomarkers were found in diabetic mice plasma based on the data of MS/MS characteristics obtained from the UPLC-OrbitrapMS analysis, which mainly involved in sphingolipids, amino acid metabolic pathway. The principal component analysis showed that the normal group and model group were obviously distinguished and implied that metabolic disturbance was happened in diabetic mice plasma. The extracts of mulberry leaf flavonoids, polysaccharide, alkaloid had exhibited the effects of callback function for diabetic mice through regulating the amino acid metabolism and sphingolipid metabolism.

The energy supply for the stimulation arrays is the key component in retinal implants. Usually, the thin film solar cell is used to supply energy, but it can not supply enough stimulation power. One of the general idea of incident energy supply is radio frequency (RF) circuit. Another method is to convert near infrared (NIR) radiation and enable retina cell stimulation. In this paper, firstly, we aim at listing these two energy supply methods, and introduce the characteristics of RF circuit and NIR conversion method. Especially, we present the design procedure in detail. The next part is a discussion on the advantage and disadvantage of adopting these two methods. At last, we explicate the new research and application of the energy supply for the use as retinal implants, and we envisage the future.
Animals ; Blindness ; rehabilitation ; Electric Power Supplies ; Electric Stimulation ; instrumentation ; methods ; Electrodes, Implanted ; Evoked Potentials, Visual ; physiology ; Humans ; Prosthesis Design ; Prosthesis Implantation ; methods ; Retina ; physiology

The application of artificial retina was introduced. The principal characteristics of artificial retina material were reviewed in particular. Moreover, the recent research development and application prospect were discussed.
Animals ; Bioartificial Organs ; trends ; Humans ; Prosthesis Design ; Retina ; Tissue Engineering ; methods

Subretinal prosthesis is one kind of retinal prosthesis, which means that a microimplant based on MEMS technology is inserted in the subretinal space to stimulate the optic nerve and elicit an electrical-evoked response on the cortical region. The subretinal implant is made up of extraocular part and intraocular part. As an important part, the latter consists of accessorial setting and stimulation chip that contains microphotodiode array (MPDA) and microelectrodes. The paper main body is made up of four parts. Firstly significance of the retinal prosthesis is given out; secondly fundamentals on both in retina physiology and retinal prosthesis theory are introduced simply. Then the key segment about the subretinal microimplant is presented in detail. In the third segment, first of all is its design concept, the second is fabrication of MPDA which consists of several parts. First is microscopic configuration, electric prototype schematic and chip image CMOS. The second is detailed fabrication flow with several special materials. Then is situation of its dimension. The fourth segment presents challenge and outlook.
Artificial Organs ; Electric Stimulation Therapy ; instrumentation ; Electrodes, Implanted ; Evoked Potentials, Visual ; physiology ; Humans ; Microelectrodes ; Prosthesis Implantation ; methods ; Retina ; physiology ; surgery ; Visual Perception ; physiology

Objective To induce an NLRP3-/- mouse model of ulcerative colitis(UC)using different concentrations of dextran sulfate sodium(DSS)and different administration times,and to analyze and evaluate the advantages and disadvantages of the preparations to provide a more suitable animal model for the study of UC pathogenesis in humans and the development of therapeutic drugs.Methods Forty-eight male NLRP3-/- specific-pathogen-free mice were divided randomly into blank,2.5％7 d,3％7 d,and 3％5 d groups(n=12 mice per group).UC mouse models were induced using combinations of different concentrations and administration times of DSS.Body weight,DAI(disease activity index)score,hematoxylin and eosin(HE)staining,colon length,and related indicators(interleukin IL-6,tumor necrosis factor(TNF)-α,and tight junction protein(ZO-1))were observed and evaluated.Results(1)UC membrane type was induced in each group with different concentrations and administration times.(2)Mouse body weight decreased,the fecal occult blood became more positive,the DAI score increased,and more mice died with increasing DSS concentration and administration time.(3)Longer administration time and higher concentration of DSS were also associated with more severe damage to the intestinal mucosa,as shown by HE staining.(4)Immunohistochemistry showed that the inflammatory factors TNF-α and IL-6 were increased in the model group compared with the blank control group,while expression of ZO-1 was decreased compared with the blank group.Conclusions(1)Administration of 2.5％or 3％DSS for 7 days or 3％DSS for 5 days can induce UC in NLRP3-/- mice.(2)The combination of DAI score,HE staining,the detection of related indicators,and mouse survival rate indicated that NLRP3-/- mice treated with 3％DSS for 5 days produced the most suitable UC model to study the clinical manifestations and drug treatment of UC.

Objective:Based on the specific cleavage and non-specific "trans-cleavage" activities of the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein(CRISPR/Cas13), we established a visually amplification-free rapid detection technique of 2019-nCoV nucleic acid. This technique is easily processed with a low detection limit and good specificity.Methods:According to the 2019-nCoV gene sequence, specific CRISPR RNAs were screened and designed by bioinformatics analysis, and then synthesized as universal signal-strained RNA transcription targets in vitro to establish and optimize the reaction system. Moreover, the 2019-nCoV pseudoviral nucleic acid was used as a standard substance to evaluate the detection limit. A total of 65 positive samples were collected from various 2019-nCoV variants, while 48 negative samples included other clinically common respiratory pathogens, such as influenza A virus, influenza B virus, human parainfluenza virus, Klebsiella pneumonia, etc. All samples were tested by quantitative PCR (qPCR), digital PCR, and the method established in this study. The sensitivity and specificity of the newly established method were analyzed and evaluated. Results:With the newly established technique, the detection time for 2019-nCoV nucleic acid could be minimized to 6 minutes. In addition, the detection limit was 14 copies/μl when assisted by the displaying instrument, whereas it increased to 28 copies/μl with the naked eye. This technique had a sensitivity and specificity of 98.5% (66/67) and 100% (46/46) respectively, showing no statistically significant difference compared to the gold standard qPCR( P=1). Conclusions:This study has successfully established a CRISPR/Cas13a-based visually rapid detection technique for 2019-nCoV nucleic acid. This technique offers the advantages of a simple process, convenient operation, low environmental operating requirements, a detection limit close to qPCR, and a strong potential for on-site testing applications.