On-line near-infrared spectroscopy optimizing and monitoring biotransformation process of γ-aminobutyric acid

AbstractNear-infrared spectroscopy (NIRS) with its fast and nondestructive advantages can be qualified for the real-time quantitative analysis. This paper demonstrates that NIRS combined with partial least squares (PLS) regression can be used as a rapid analytical method to simultaneously quantify l-glutamic acid (l-Glu) and γ-aminobutyric acid (GABA) in a biotransformation process and to guide the optimization of production conditions when the merits of NIRS are combined with response surface methodology. The high performance liquid chromatography (HPLC) reference analysis was performed by the o-phthaldialdehyde pre-column derivatization. NIRS measurements of two batches of 141 samples were firstly analyzed by PLS with several spectral pre-processing methods. Compared with those of the HPLC reference analysis, the resulting determination coefficients (R2), root mean square error of prediction (RMSEP) and residual predictive deviation (RPD) of the external validation for the l-Glu concentration were 99.5%, 1.62g/L, and 11.3, respectively. For the GABA concentration, R2, RMSEP, and RPD were 99.8%, 4.00g/L, and 16.4, respectively. This NIRS model was then used to optimize the biotransformation process through a Box-Behnken experimental design. Under the optimal conditions without pH adjustment, 200g/L l-Glu could be catalyzed by 7148 U/L glutamate decarboxylase (GAD) to GABA, reaching 99% conversion at the fifth hour. NIRS analysis provided timely information on the conversion from l-Glu to GABA. The results suggest that the NIRS model can not only be used for the routine profiling of enzymatic conversion, providing a simple and effective method of monitoring the biotransformation process of GABA, but also be considered to be an optimal tool to guide the optimization of production conditions

The global/local (limited to some regions) effect of cesarean delivery on the risk of pediatric allergic rhinitis: a systematic review and meta-analysis

BackgroundAllergic rhinitis is a chronic and refractory disease that can be affected by a variety of factors. Studies have shown an association between cesarean section and the risk of pediatric allergic rhinitis.MethodsThe PubMed, Springer, Embase, Cochrane Library, and Web of Science databases were searched to retrieve all studies published from January 2000 to November 2022, focusing on the relationship between cesarean section and the risk of pediatric allergic rhinitis. A meta-analysis was conducted to find a correlation between cesarean section and the risk of pediatric allergic rhinitis. A subgroup analysis was performed, considering the region and family history of allergy, after adjusting for confounding factors. Pooled odds ratios (ORs) were calculated, publication bias was assessed using a funnel plot, and heterogeneity between study-specific relative risks was taken into account.ResultsThe results showed that cesarean section was significantly associated with an increased risk of pediatric allergic rhinitis (OR: 1.27, 95% CI: 1.20–1.35). Subgroup analysis stratified by region indicated that cesarean section increased the risk of pediatric allergic rhinitis, with the highest increase in South America (OR: 1.67, 95% CI: 1.10–2.52) and the lowest in Europe (OR: 1.13, 95% CI: 1.02–1.25). The results of the subgroup analysis stratified by family history of allergy indicate that family history of allergy was not associated with the risk of pediatric allergic rhinitis.ConclusionAn association exists between cesarean section as the mode of delivery and the increased risk of pediatric allergic rhinitis, and cesarean section is a risk factor for allergic rhinitis

Study on mechanical properties and damage characteristics of granite under thermal shock based on CT scanning

During the exploitation of deep geothermal resources, the thermal fractures of high-temperature rocks are usually induced by the impact of low-temperature fluids to improve the permeability of reservoir rocks. In order to reveal the damage and fracture mechanism of rock after thermal shock, the granites heated at high temperature (20 ℃, 150 ℃, 300 ℃, 450 ℃, 600 ℃ and 750 ℃) were treated by natural cooling and water cooling respectively, and the wave velocity test, uniaxial compression test and CT scanning were carried out on the treated granites. The mechanical effect of thermal shock on P-wave velocity, compressive strength and elastic modulus of granite were also discussed. The experimental results show that with the increase of heat treatment temperature, the P-wave velocity, compressive strength, and elastic modulus of rock gradually decrease, and the peak strain gradually increases. Compared with natural cooling, the wave velocity and mechanical properties of rock deteriorate more significantly after water cooling. Based on CT scanning, the spatial distribution characteristics of pore and fracture structure of granite under different heating temperatures and heat treatment methods were obtained, which can directly reflect the thermal damage degree of rock microstructure. When the heat treatment temperature is not higher than 450 ℃, the number and size of thermally induced cracks in granite scanning slices are less and the connectivity of cracks is relatively poor. When the temperature exceeds 450 ℃, the micro-cracks in granite develop and expand rapidly, and tend to form fracture network gradually, and the damage and cracking effect of water cooling on the microscomic-structure of granite is more obvious than that of natural cooling. In addition, based on triangular mesh discretization technique, ellipsoid model reconstruction algorithm and fracture tensor calculation theory, the three-dimensional fracture field of granite after thermal shock is quantitatively characterized, and the relationship between fracture fabric tensor and peak strength was established, which further reveals the influence mechanism of granite microscomic-structure on its mechanical properties under thermal shock

Electro-optic response of polymer-stabilized blue phase liquid crystals

The dynamic response of a polymer-stabilized blue phase liquid crystal (BPLC) is comprised of two distinct processes: Kerr effect-induced local reorientation and electrostriction-induced lattice distortion. A double exponential rise/decay model is proposed to analyze the underlying physical mechanisms. If the electric field is below a critical field (E-c), Kerr effect dominates and the response time is fast. However, when E \u3e E-c electrostriction effect manifests, leading to an increased response time and a noticeable hysteresis. A higher polymer concentration helps suppress electrostriction, but the tradeoff is increased operation voltage. These results provide useful guidelines for future BPLC material and device optimizations

Differential and Prognostic Significance of HOXB7 in Gliomas

Diffuse glioma is the most common primary tumor of the central nervous system. The prognosis of the individual tumor is heavily dependent on its grade and subtype. Homeobox B7 (HOXB7), a member of the homeobox family, is abnormally overexpressed in a variety of tumors. However, its function in glioma is unclear. In this study, HOXB7 mRNA and protein expression levels were analyzed in 401 gliomas from the CGGA RNA-seq database (325 cases) and our hospital (76 cases). HOXB7 expression, at both mRNA and protein levels, were upregulated in glioblastoma (GBM) and isocitrate dehydrogenase 1 (IDH1) wild-type glioma tissues. Kaplan–Meier with log-rank test showed that patients with high HOXB7 expression had a poor prognosis (p < 0.0001). Moreover, HOXB7 protein was deleted in 90.9% (20/22) of oligodendrogliomas and 13.0% (3/23) of astrocytomas. The sensitivity and specificity of HOXB7 protein deletion in oligodendroglioma were 90.9% (20/22) and 87.0% (20/23), respectively. To verify the reliability of using HOXB7 in differentiating oligodendroglioma, we used 1p/19q fluorescence in situ hybridization (FISH) testing as a positive control. The Cohen’s kappa coefficient of HOXB7 immunohistochemistry staining and 1p/19q FISH testing was 0.778 (95% CI: 0.594–0.962, p < 0.001). In conclusion, HOXB7 is an independent predictor of poor prognosis in all grade gliomas. Additionally, HOXB7 is also a highly sensitive and specific indicator to differentiate oligodendroglioma from astrocytoma