Role of the gut microbiota and innate immunity in polycystic ovary syndrome: Current updates and future prospects.

Polycystic ovary syndrome (PCOS) is one of the modern intractable reproductive diseases. The female irregular menstruation, infertility, obesity, and so forth caused by PCOS have become a hot issue affecting family harmony and social development. The aetiology of PCOS is complex. In recent years, many scholars have found that its pathogenesis was related to the imbalance of gut microbiota. Gut microbiota can form two-way communication with the brain through the 'gut-brain axis' and affect the host's metabolism. Current research has confirmed that the gut microbiota can interfere with glucose and lipid metabolism, insulin sensitivity, hormone secretion and follicular development in women by altering intestinal mucosal permeability and secreting metabolites. In addition, the diversity and composition of gut microbiota of PCOS patients changed, which may affect the metabolic function of the gut microbiota and the ability to produce metabolites, and may also directly or indirectly affect the endocrine function. This study reviewed recent research advances about the role of gut microbiota in PCOS. In order to provide basis for prevention and treatment of PCOS based on gut microbiota.

Fast online evaluation of vegetable freshness using single turnover chlorophyll fluorescence.

Vegetable freshness evaluation is of great significance to ensure the quality of vegetables and realize fine production. Existing vegetable freshness evaluation methods have difficulty realizing rapid online evaluation and industrial applications due to such disadvantages as being susceptible to subjective factors, complicated operation, large computation, and high hardware cost. To solve the above problems, a rapid online vegetable freshness evaluation method was developed based on the single turnover chlorophyll fluorescence parameters Fo', Fv'/Fm' and σPSII'. A freshness evaluation model for spinach and swamp cabbage was established based on a classification and regression tree algorithm, using Fo', Fv'/Fm' and σPSII' as sample features. The model divided the freshness of spinach and swamp cabbage into three grades: good, medium, and poor, and the leave-one-out cross validation results showed that the freshness evaluation accuracies of spinach and swamp cabbage reached 98.1% and 94.3%, respectively.

Quantifying PAHs in water by three-way fluorescence spectra and second-order calibration methods.

It is still difficult to determine the concentrations of polycyclic aromatic hydrocarbons accurately in natural water by fluorescence technique because of their low solubility, different fluorescent intensity, and the complex interferents from water environments. In this work, three-way fluorescence spectra combined with three methods including three-way parallel factor analysis, multi-way partial least square with residual bilinearization and unfolded partial least square with residual bilinearization were used to predict the concentrations of polycyclic aromatic hydrocarbons at the µg L-1 level in reservoir and river water, respectively. The prediction abilities of these methods on different analytes were evaluated by validation sets. The results demonstrate that unfolded partial least square with residual bilinearization yields the optimal results with relative error less than or equal to 6% for phenanthrene, pyrene, anthracene and fluorene, and 35% for acenaphthene and fluoranthene in different water backgrounds.

[Laser Induced Time-Resolved Fluorescence Spectroscopy Characteristics of Fluoranthene in Ethanol with Eanosecond Laser of 355 nm].

Polycyclic Aromatic Hydrocarbons (PAHs) have been widely investigated in environmental field, for most of them are mutagenic (carcinogenic, teratogenic, mutagenic). The influence of delay time and gate width on the time-resolved fluorescence spectroscopy of fluoranthene in ethanol was studied in this paper. Furthermore, laser induced time-resolved fluorescence spectroscopy of fluoranthene with different concentration were also researched. According to the results, fluorescence kinetics decay curves and fluorescence lifetime of fluoranthene matched. The research results showed that there was closely relationship between the fluorescence spectrum of fluoranthene and the delay time and gate width of detector. When the delay time was fixed, the fluorescence intensity of fluoranthene grew increased as the gate width increased. When the gate width was fixed, the fluorescence intensity of fluoranthene increased first and then decreased with the delay time increases. The process of the attenuation of fluorescence intensity of fluoranthene with time delay conformed to the exponential decay process. The stepwise dilution of fluoranthene ethanol solution was also studied. With increasing dilution, the fitting of fluoranthene fluorescence lifetime increased. The results of this paper can provide a technical basis for the detection of PAHs in the environment, due to the different characteristics of the fluorescent substance having fluorescence lifetime.

[Effect of Methanol-Water Mixture on Three-Dimensional Fluorescence Spectra of Carbaryl].

Extensive use of pesticides has a significant impact on the environment. Carbaryl, whose residues stay in the surface water, is one of the most widely used broad spectrum insecticides in agriculture. It is important to understand carbaryl spectral characteristics and detection methods. The characteristic of excitation-emission three-dimensional spectra of carbaryl is studied. By changing the concentration of methanol in methanol-water binary solvent, the impact of methanol-water mixture on three-dimensional fluorescence spectra of carbaryl is discussed. The results show that the characteristic excitation-emission spectra of carbaryl is single peak, the range of the excitation wavelength and emission wavelength are: 244~304 and 300~350 nm respectively, the maximum excitation/emission peak located at 280 and 335 nm. With increasing the content of methanol in methanol-water binary solvent mixture, there is no obviously spectra shift of three dimensional fluorescence spectra of carbaryl. However, the intensity of fluorescence is nonlinear dependent on the content of methanol, mainly due to the specific properties of binary mixed solvent.

[Outlier Detection of Time Series Three-Dimensional Fluorescence Spectroscopy].

The qualitative and quantitative analysis are often interfered by the outliers in time series three-dimensional fluorescence spectroscopy. In this work, an efficient outlier detection method is proposed by taking advantage of the characteristics in time dimension and the spectral dimension. Firstly, the wavelength points that are mostly the outliers are extracted by the variance in time dimension. Secondly, by the analysis of the existence styles of outliers and similarity score of any two samples, the cumulative similarity is introduced in spectral dimension. At last, fluorescence intensity at each wavelength of all samples is modified by the correction matrix in time dimension and the outlier detection is completed according the to cumulative similarity scores. The application of the correction matrix in time dimension not only improves the validity of the method but also reduces the computation by the choice of characteristics region in correction matrix. Numerical experiments show that the outliers can still be detected by the 50 percent of all points in spectral dimension.

Cognitive impairment in Chinese traumatic brain injury patients: from challenge to future perspectives.

Traumatic Brain Injury (TBI) is a prevalent form of neurological damage that may induce varying degrees of cognitive dysfunction in patients, consequently impacting their quality of life and social functioning. This article provides a mini review of the epidemiology in Chinese TBI patients and etiology of cognitive impairment. It analyzes the risk factors of cognitive impairment, discusses current management strategies for cognitive dysfunction in Chinese TBI patients, and summarizes the strengths and limitations of primary testing tools for TBI-related cognitive functions. Furthermore, the article offers a prospective analysis of future challenges and opportunities. Its objective is to contribute as a reference for the prevention and management of cognitive dysfunction in Chinese TBI patients.

Probing amino acid side chains of the integral membrane protein PagP by solution NMR: Side chain immobilization facilitates association of secondary structures.

Solution NMR spectroscopy of large protein systems is hampered by rapid signal decay, so most multidimensional studies focus on long-lived 1H-13C magnetization in methyl groups and/or backbone amide 1H-15N magnetization in an otherwise perdeuterated environment. Herein we demonstrate that it is possible to biosynthetically incorporate additional 1H-12C groups that possess long-lived magnetization using cost-effective partially deuterated or unlabeled amino acid precursors added to Escherichia coli growth media. This approach is applied to the outer membrane enzyme PagP in membrane-mimetic dodecylphosphocholine micelles. We were able to obtain chemical shift assignments for a majority of side chain 1H positions in PagP using nuclear Overhauser enhancements (NOEs) to connect them to previously assigned backbone 1H-15N groups and newly assigned 1H-13C methyl groups. Side chain methyl-to-aromatic NOEs were particularly important for confirming that the amphipathic α-helix of PagP packs against its eight-stranded ß-barrel, as indicated by previous X-ray crystal structures. Interestingly, aromatic NOEs suggest that some aromatic residues in PagP that are buried in the membrane bilayer are highly mobile in the micellar environment, like Phe138 and Phe159. In contrast, Tyr87 in the middle of the bilayer is quite rigid, held in place by a hydrogen bonded network extending to the surface that resembles a classic catalytic triad: Tyr87-His67-Asp61. This hydrogen bonded arrangement of residues is not known to have any catalytic activity, but we postulate that its role is to immobilize Tyr87 to facilitate packing of the amphipathic α-helix against the ß-barrel.

[Analysis of three-dimensional fluorescence overlapping spectra using differential spectra and independent component analysis].

The analysis of multi-component three-dimensional fluorescence overlapping spectra is always very difficult. In view of the advantage of differential spectra and based on the calculation principle of two-dimensional differential spectra, the three-dimensional fluorescence spectra with both excitation and emission spectra is fully utilized. Firstly, the excitation differential spectra and emission differential spectra are respectively computed after unfolding the three-dimensional fluorescence spectra. Then the excitation differential spectra and emission differential spectra of the single component are obtained by analyzing the multicomponent differential spectra using independent component analysis. In this process, the use of cubic spline increases the data points of excitation spectra, and the roughness penalty smoothing reduces the noise of emission spectra which is beneficial for the computation of differential spectra. The similarity indices between the standard spectra and recovered spectra show that independent component analysis based on differential spectra is more suitable for the component recognition of three-dimensional fluorescence overlapping spectra.

Cost-effective selective deuteration of aromatic amino acid residues produces long-lived solution 1H NMR magnetization in proteins.

Solution NMR studies of large proteins are hampered by rapid signal decay due to short-range dipolar 1H-1H and 1H-13C interactions. These are attenuated by rapid rotation in methyl groups and by deuteration (2H), so selective 1H,13C-isotope labelling of methyl groups in otherwise perdeuterated proteins, combined with methyl transverse relaxation optimized spectroscopy (methyl-TROSY), is now standard for solution NMR of large protein systems > 25 kDa. For non-methyl positions, long-lived magnetization can be introduced as isolated 1H-12C groups. We have developed a cost-effective chemical synthesis for producing selectively deuterated phenylpyruvate and hydroxyphenylpyruvate. Feeding these amino acid precursors to E. coli in D2O, along with selectively deuterated anthranilate and unlabeled histidine, results in isolated and long-lived 1H magnetization in the aromatic rings of Phe (HD, HZ), Tyr (HD), Trp (HH2, HE3) and His (HD2 and HE1). We are additionally able to obtain stereoselective deuteration of Asp, Asn, and Lys amino acid residues using unlabeled glucose and fumarate as carbon sources and oxalate and malonate as metabolic inhibitors. Combining these approaches produces isolated 1H-12C groups in Phe, Tyr, Trp, His, Asp, Asn, and Lys in a perdeuterated background, which is compatible with standard 1H-13C labeling of methyl groups in Ala, Ile, Leu, Val, Thr, Met. We show that isotope labeling of Ala is improved using the transaminase inhibitor L-cycloserine, and labeling of Thr is improved through addition of Cys and Met, which are known inhibitors of homoserine dehydrogenase. We demonstrate the creation of long-lived 1H NMR signals in most amino acid residues using our model system, the WW domain of human Pin1, as well as the bacterial outer membrane protein PagP.

Ensemble calibration model of near-infrared spectroscopy based on functional data analysis.

As a nondestructive detection technology, near-infrared spectroscopy has been widely applied in various fields. With the wide application of near-infrared spectroscopy, the research on data processing has attracted more attention. Different from the existing discrete data model and based on the functional data analysis method, an ensemble calibration model FDA-EM-PLS (functional data analysis-ensemble learning-partial least squares) of near-infrared spectroscopy is proposed in this paper. Firstly, the near-infrared spectroscopy of each sample is divided into several intervals, and the functional data analysis is carried out on each interval. Then, the samples are clustered according to the generated functions, which can not only reduce the influence of noise, but also provide a theoretical basis for selecting variables. Further, Monte Carlo sampling is used to generate training subsets from clustering samples for ensemble learning, which not only solves the problem of small samples, but also improves the robustness of the model. The relevant experimental results show that the absolute relative error of FDA-EM-PLS for the corn and soil data are both less than 10%.

Adjustable Handheld Probe Design for Photoacoustic Imaging: Mathematical Modelling and Simulation Study.

Photoacoustic imaging is an emerging imaging technique that combines light illumination and ultrasound detection. Conventional design of photoacoustic probe usually combines light and sound in a straightforward way without any adjustable capability. In this paper, we propose a new photoacoustic imaging system based on light-adjustable handheld probe. Compared with traditional design of photoacoustic probe, our proposed apparatus has the following advantages: (1) Spot size and distance are adjustable. By tuning parameters, it can achieve bright-field, dark-field, and mixed-field light illumination schemes. (2) Different excitation modes can be selected as needed. Monte Carlo simulation results show that distinct light fields have different excitation advantages for optimizing photoacoustic generation. Both simulation and experimental testing results demonstrate the proposed system to have great potential in biomedical imaging with versatile configurations.

Adjustable Handheld Probe Design for Photoacoustic Imaging:Experimental Validation.

Photoacoustic (PA) imaging is an emerging imaging technique that combines light illumination and ultrasound detection. Conventional design of PA probe usually combines light and sound in a straightforward way without adjustable capability. In this paper, we propose a new PA imaging system based on light-adjustable handheld probe. The proposed PA imaging system includes a control unit that can adaptively find the light illumination pattern for the PA signal generation with optimized signal-to-noise ratio (SNR). Compared with traditional design of PA probe, our proposed apparatus enables the following advantages: (1) The system can automatically find the specific position parameters of the illumination scheme, and obtain the PA signal with optimized SNR by implementing a scanning process. (2) The proposed apparatus can be fully automatic and adaptive by electronic control. By scanning the sample, it can automatically obtain the optimized light exposure position. (3) Spot size and distance are adjustable. Both simulation and experimental results demonstrate the feasibility of the proposed system to have great potential in biomedical imaging with versatile configurations.

Weighted partial least squares based on the error and variance of the recovery rate in calibration set.

The quantitative analysis is very difficult for the emission-excitation fluorescence spectroscopy of multi-component mixtures whose fluorescence peaks are serious overlapping. As an effective method for the quantitative analysis, partial least squares can extract the latent variables from both the independent variables and the dependent variables, so it can model for multiple correlations between variables. However, there are some factors that usually affect the prediction results of partial least squares, such as the noise, the distribution and amount of the samples in calibration set etc. This work focuses on the problems in the calibration set that are mentioned above. Firstly, the outliers in the calibration set are removed by leave-one-out cross-validation. Then, according to two different prediction requirements, the EWPLS method and the VWPLS method are proposed. The independent variables and dependent variables are weighted in the EWPLS method by the maximum error of the recovery rate and weighted in the VWPLS method by the maximum variance of the recovery rate. Three organic matters with serious overlapping excitation-emission fluorescence spectroscopy are selected for the experiments. The step adjustment parameter, the iteration number and the sample amount in the calibration set are discussed. The results show the EWPLS method and the VWPLS method are superior to the PLS method especially for the case of small samples in the calibration set.

Determination of Polycyclic Aromatic Hydrocarbons in the Presence of Humic Acid in water.

The presence of humic acid (HA) makes it extremely difficult to determine and quantify accurately polycyclic aromatic hydrocarbons (PAHs) in aquatic environment because of their complex and strong interaction. To solve this problem, a new method was developed in this work through the combination of PARAFAC and fluorescence spectroscopy, which mainly includes: (1) the fluorescence quantum yield acquisition of PAHs with and without HA by PARAFAC; (2) the concentration score correction of PAHs in validation and test sets using the fluorescence quantum yields; and (3) the prediction of PAHs concentration in the validation and test sets in the presence of HA by corrected concentration. Using this method, the PAHs concentration on the level of µg L(-1) in the test samples with HA of 2.5 mg/L and 5.0 mg/L can be successfully predicted with the root mean square error below 0.15 µg L(-1), relative error of prediction below 4% for validation samples, recoveries of each PAH between 82.5% and 102.6% for test samples.

Determination of polycyclic aromatic hydrocarbons by four-way parallel factor analysis in presence of humic acid.

There is not effective method to solve the quenching effect of quencher in fluorescence spectra measurement and recognition of polycyclic aromatic hydrocarbons in aquatic environment. In this work, a four-way dataset combined with four-way parallel factor analysis is used to identify and quantify polycyclic aromatic hydrocarbons in the presence of humic acid, a fluorescent quencher and an ubiquitous substance in aquatic system, through modeling the quenching effect of humic acid by decomposing the four-way dataset into four loading matrices corresponding to relative concentration, excitation spectra, emission spectra and fluorescence quantum yield, respectively. It is found that Phenanthrene, pyrene, anthracene and fluorene can be recognized simultaneously with the similarities all above 0.980 between resolved spectra and reference spectra. Moreover, the concentrations of them ranging from 0 to 8µgL(-1) in the test samples prepared with river water could also be predicted successfully with recovery rate of each polycyclic aromatic hydrocarbon between 100% and 120%, which were higher than those of three-way PARAFAC. These results demonstrate that the combination of four-way dataset with four-way parallel factor analysis could be a promising method to recognize the fluorescence spectra of polycyclic aromatic hydrocarbons in the presence of fluorescent quencher from both qualitative and quantitative perspective.

A novel initialization method for nonnegative matrix factorization and its application in component recognition with three-dimensional fluorescence spectra.

Nonnegative matrix factorization has been widely used in many areas and has been applied for component recognition with three dimensional fluorescence spectra recently. However, nonnegative matrix factorization is a nonconvex programming in the iteration process, thus the solution is dependent on the initial values and consequently not unique. Up to now, an effective global convergent algorithm is still absent. In this work, we propose an initialization scheme based on independent component analysis. Compared with other initialization schemes, the optimal solution of nonnegative matrix factorization based on independent component analysis is much better and it is demonstrated by typical experiments of component recognition with three-dimensional fluorescence spectra.

Hydrothermal synthetic mercaptopropionic acid stabled CdTe quantum dots as fluorescent probes for detection of Ag⁺.

Mercaptopropionic acid (MPA) capped CdTe quantum dots (QDs) with particle size 3 nm have been successfully synthesized in aqueous medium by hydrothermal synthesis method. And the effects of different metal ions on MPA capped CdTe QDs fluorescence were studied using fluorescence spectrometry. The results demonstrated that at the same concentration level, Ag(+) could strongly quench CdTe QDs fluorescence, and the other metal ions had little effect on CdTe QDs fluorescence except Cu(2+). On the basis of this fact, a rapid, simple, highly sensitive and selective method based on fluorescence quenching principle for Ag(+) detection in aqueous solution was proposed. Under optimal conditions, the quenched fluorescence intensity (F(0)-F) increased linearly with the concentration of Ag(+) ranging from 4 × 10(-7) to 32 × 10(-7)mol L(-1). The limit of detection for Ag(+) was 4.106 × 10(-8)mol L(-1). The obtained plot of F(0)/F versus [Ag(+)] was an upward curvature, concave towards the y-axis, rather than a straight line. The modified form of the Stern-Volmer equation was third order in Ag(+) concentration. According to the modified Stern-Volmer equation, it can be inferred that dynamic quenching and static quenching simultaneously occurred when Ag(+) interacted with MPA capped CdTe QDs. At the same time other factors might also influence the quenching process. Based on this study, hydrothermal synthesized MPA capped CdTe QDs with particle size 3 nm may be used as a novel fluorescence probe to quantificationally and selectively detect Ag(+).

Application of excitation-emission matrix fluorescence combined with second-order calibration algorithm for the determination of five polycyclic aromatic hydrocarbons simultaneously in drinking.

Direct determination of five polycyclic aromatic hydrocarbons including fluorene, anthracene, phenanthrene, pyrene and fluoranthene was accomplished by excitation-emission matrix fluorescence coupled with chemometric methods based on an alternating trilinear decomposition (ATLD) algorithm. A uniform design and orthogonal design are proposed for the creation of the calibration set. Results showed that no significant difference in the recoveries for each of the PAHs was observed. Thus, both of the designs can be used for the calibration set. In addition, some statistical parameters and figures of merit, such as average recovery, root-mean-square error of prediction, sensitivity, and selectivity were investigated to evalute the performance of the proposed method. The results showed that fluoranthene was the most selective, whereas fluorene was more sensitive than any other compound. This method was also employed for the determination of samples of drinking water spiked with all these PAHs. It can be observed that the results were not as satisfying as those in synthetic samples due to the negative effects of humic acid or fulvic acid in drinking water.

Integrated similarity indices for component recognition in mixtures with three-dimensional fluorescence spectra.

Component recognition is a very important issue in the analysis of mixed three-dimensional fluorescence spectra and it can be realized by calculating the similarity index between the reference spectra and the computed spectra from the trilinear decomposition of the three-dimensional data arrays. However, the most popular similarity index available in the literature for processing three-dimensional fluorescence spectra takes advantage of only part of the information from the trilinear decomposition. It works well when there are clear differences between the component spectra, but it may fail when the spectra are severely overlapped. In order to overcome the shortcomings and to adapt to the rapid development of online monitoring, we propose a type of integrated similarity index (ISI) that is particularly superior for component recognition in mixtures with severely overlapped spectra. The ISI makes full use of as much information of the three-dimensional fluorescence spectra as possible, namely, of both the waveform and the characteristic peak wavelength, as well as both the emission spectra and the excitation spectra. With the ISI, the recognition process can be accomplished automatically and more accurately in extreme cases than the traditionally defined similarity indices that are based on only one specific feature. The feasibility of the ISI is demonstrated by experiments with mixtures of phenol, cresol, and thymol.