4-Hydroxybenzoate (4HBA) is an important chemical compound used for synthesis of liquid crystal. Production of 4HBA from renewable resources is an effective mean to solve problems such as environmental pollution and petroleum shortage. This review briefly introduces the chemical synthesis of 4HBA from oil compounds, and mainly describes the progress in 4HBA biosynthesis from renewable resources by plants and microorganisms. In most intriguing aspect of plant-based synthesis of 4HBA is the appeal of directly synthesizing a chemical from CO2. However, the glucosylation system in plant cells converting 4HBA to glucose conjugates, causing the post treatment a problem. The recombinant microorganisms produce pure 4HBA, but less efficient. A new strain of Microbulbifer has ability to naturally accumulate 4HBA from glucose. Elucidation of the metabolic pathways and regulation systems would improve 4HBA synthesis efficiency.
Alteromonadaceae ; metabolism ; Glucose ; chemistry ; Glycosylation ; Industrial Microbiology ; Metabolic Networks and Pathways ; Parabens ; metabolism ; Plants ; metabolism

BACKGROUND:At present, there are many researches about repairing articular cartilage defects. In particular, the microfracture technique has been widely used. OBJECTIVE:To observe recovery of knee joint motor function and morphological changes in tissue repair during articular cartilage defects with different directions (coronal position and sagittal position). METHODS:Articular cartilage fracture models with 2 mm-thick medial femoral condyles of rabbit knee joint were established. According to incision directions, models were assigned to coronal and sagittal groups. At 5, 10 and 20 weeks after model induction, general observation was performed. Specimens were sliced into paraffin sections, and subjected to hematoxylin-eosin staining and col agen staining. Tissue repair at the articular cartilage defects was observed using optical microscope and immunohistochemical method. After model induction, range of motion of rabbit joints was regularly examined in the two groups.RESULTS AND CONCLUSION:A white line was seen across the femoral condyles at defects in the two groups. Articular surface at defect repair was at the level of in situ cartilage, and reached a bone union. Knee joint treated by operation did not affect function. Under light microscope, partial reconstruction of subchondral bone was seen in the two groups, mainly fibrocartilage repair. The level of bony remodeling was lower than tidal line of adjacent in situ cartilage. Immunohistochemical method exhibited that type I col agen staining gradual y reduced at defects of specimens, but type II col agen staining gradual y increased. These results suggested that there was no significant difference in the recovery of motor function of knee joint and the repair of articular cartilage with different directions (coronal and sagittal position).

Objective:To explore the feasibility of a classification prediction model for gamma pass rates (GPRs) under different intensity-modulated radiation therapy techniques for pelvic tumors using a radiomics-based machine learning approach, and compare the classification performance of four integrated tree models.Methods:With a retrospective collection of 409 plans using different IMRT techniques, the three-dimensional dose validation results were adopted based on modality measurements, with a GPR criterion of 3%/2 mm and 10% dose threshold. Then prediction were built models by extracting radiomics features based on dose documentation. Four machine learning algorithms were used, namely random forest (RF), adaptive boosting (AdaBoost), extreme gradient boosting (XGBoost), and light gradient boosting machine (LightGBM). Their classification performance was evaluated by calculating sensitivity, specificity, F1 score, and AUC value. Results:The RF, AdaBoost, XGBoost, and LightGBM models had sensitivities of 0.96, 0.82, 0.93, and 0.89, specificities of 0.38, 0.54, 0.62, and 0.62, F1 scores of 0.86, 0.81, 0.88, and 0.86, and AUC values of 0.81, 0.77, 0.85, and 0.83, respectively. XGBoost model showed the highest sensitivity, specificity, F1 score, and AUC value, outperforming the other three models. Conclusions:To build a GPR classification prediction model using a radiomics-based machine learning approach is feasible for plans using different intensity-modulated radiotherapy techniques for pelvic tumors, providing a basis for future multi-institutional collaborative research on GPR prediction.

OBJECTIVE: To compare the effectiveness of posterolateral approach lumbar interbody fusion assisted by one-hole split endoscope (OSE) and traditional posterior lumbar interbody fusion (PLIF) in the treatment of L_{4, 5} degenerative lumbar spondylolisthesis (DLS). METHODS: The clinical data of 58 patients with DLS who met the selection criteria admitted between February 2020 and March 2022 were retrospectively analyzed, of which 26 were treated with OSE-assisted posterolateral approach lumbar interbody fusion (OSE group) and 32 were treated with PLIF (PLIF group). There was no significant difference between the two groups in terms of gender, age, body mass index, Meyerding grade, lower limb symptom side, decompression side, stenosis type, and preoperative low back pain visual analogue scale (VAS) score, leg pain VAS score, Oswestry disability index (ODI), and the height of the anterior and posterior margins of the intervertebral space (P>0.05). The operation time, intraoperative blood loss, postoperative hospital stay, and complications were compared between the two groups. The low back pain and leg pain VAS scores and ODI before operation, at 1 month, 6 months after operation, and last follow-up, the height of anterior and posterior margins of the intervertebral space before operation, at 6 months after operation, and last follow-up, the modified MacNab criteria at last follow-up after operation were used to evaluate the effectiveness; and the Bridwell method at last follow-up was used to evaluate the interbody fusion. RESULTS: Both groups successfully completed the operation. Compared with the PLIF group, the OSE group showed a decrease in intraoperative blood loss and postoperative hospital stay, but an increase in operation time, with significant differences (P<0.05). In the OSE group, no complication such as nerve root injury and thecal sac tear occurred; in the PLIF group, there were 1 case of thecal sac tear and 1 case of epidural hematoma, which were cured after conservative management. Both groups of patients were followed up 13-20 months with an average of 15.5 months. There was no complication such as loosening, sinking, or displacement of the fusion cage. The low back pain and leg pain VAS scores, ODI, and the height of anterior and posterior margins of the intervertebral space at each time point after operation in both groups were significantly improved when compared with those before operation (P<0.05). Except for the VAS score of lower back pain in the OSE group being significantly better than that in the PLIF group at 1 month after operation (P<0.05), there was no significant difference in all indicators between the two groups at all other time points (P>0.05). At last follow-up, both groups achieved bone fusion, and there was no significant difference in Bridwell interbody fusion and modified MacNab standard evaluation between the two groups (P>0.05). CONCLUSION OSE-assisted posterolateral approach lumbar interbody fusion for L_{4, 5} DLS, although the operation time is relatively long, but the postoperative hospitalization stay is short, the complications are few, the operation is safe and effective, and the early effectiveness is satisfactory.
Humans ; Spondylolisthesis/surgery* ; Low Back Pain/surgery* ; Retrospective Studies ; Lumbosacral Region ; Blood Loss, Surgical ; Endoscopes