Green Synthesis of MOF-801(Zr/Ce/Hf) for CO2/N2 and CO2/CH4 Separation.

The purification of natural gas and the removal of carbon dioxide from flue gases are crucial to economize precious resources and effectively relieve a series of environmental problems caused by global warming. Metal-organic framework (MOF) materials have demonstrated remarkable performance and benefits in the area of gas separation; however, obtaining materials with high gas capacity and selectivity simultaneously remains difficult. In addition, harsh synthesis conditions and solvent toxicity have been restricted in large-scale production and industrial application. Therefore, MOF-801(Zr/Ce/Hf) was created based on the green synthesis of the MOF-801 construction unit by altering the kinds of metal salts, and the impact of three metal nodes on the performance of gas adsorption and separation was demonstrated by contrasting the three MOFs. The results showed that MOF-801(Ce) has the best CO2 adsorption capacity (3.3 mmol/g at 298 K), which also was demonstrated with in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) results, CO2/CH4 (ideal adsorbed solution theory (IAST) = 13.28 at 298 K, 1 bar, CO2/CH4 = 1:1, v/v), and the separation performance of CO2/N2 (IAST = 57.46 at 298 K, 1 bar, CO2/N2 = 1:1, v/v) among the group. Green synthesis of MOF-801(Zr/Ce/Hf) is an ideal candidate for flue gas separation and methane purification because of its high regeneration capacity and strong cyclic stability.

Palladium Nanoparticles Encapsulated in the MIL-101-Catalyzed One-Pot Reaction of Alcohol Oxidation and Aldimine Condensation.

A bifunctional catalyst, Pd nanoparticles (NPs) encapsulated in MIL-101, has been synthesized by capillary impregnation. The as-prepared Pd@MIL-101 was characterized by powder X-ray diffraction, N2 physisorption, X-ray photoelectron spectroscopy, transmission electron microscopy, and high-angle annular dark field scanning transmission electron microscopy, indicating that Pd NPs were highly dispersed in the pores of MIL-101 without deposition of the nanoparticles on the external surface or aggregation. The bifunctional catalyst of Pd@MIL-101 exhibited highly catalytic activity for alcohol oxidation and aldimine condensation one-pot reactions, where Pd NPs affords good oxidation activity and MIL-101 offers Lewis acidity. In particular, Pd@MIL-101 yielded an effective catalytic performance with toluene as the solvent, K2CO3 as the co-catalyst, and 353 K as the optimum reaction temperature for the one-pot reaction. After five cycles of reuse, Pd@MIL-101 still shows high catalytic performance. Above all, it is found that the enhanced catalytic performance was achieved via the synergistic cooperation of MIL-101 and Pd NPs.

Association between polymorphisms of autophagy pathway and responses in non-small cell lung cancer patients treated with platinum-based chemotherapy.

Platinum-based chemotherapy is an important treatment for non-small cell lung cancer. However, the effectiveness of the treatment varies among the patients. We investigated the association between DNA polymorphisms of the autophagy pathway and responses of such treatment among 1004 Chinese patients. Ninety-nine SNPs located on 13 genes of the autophagy pathway were genotyped and assessed for their association with clinical benefit, progression-free survival (PFS) and overall survival (OS). The results showed that rs7953348 (G>A) (P=0.017, OR: 0.67, 95%CI: 0.49-0.93) and rs12303764 (A>C) (P=0.009, OR: 0.63, 95%CI: 0.45-0.89) at the ULK1 gene, and rs17742719 (C>A) (P=0.002, OR: 1.83, 95%CI: 1.26-2.66), rs8003279 (A>G) (P=0.006, OR: 1.65, 95%CI: 1.16~2.35) and rs1009647 (G>A) (P=0.002, OR: 1.70, 95%CI: 1.22-2.37) at the ATG14 gene were associated with clinical benefit. Polymorphisms at rs7955890 (G>A) (P=0.004, HR: 0.63; 95%CI: 0.46-0.86) and rs17032060 (G>A) (P=0.006, HR: 0.65, 95%CI: 0.48-0.88) at the DRAM gene, and rs13082005 (G>A) (P=0.012, HR: 1.27, 95%CI: 1.05-1.53) at the ATG3 gene were significantly associated with PFS. We also found that rs7953348 (G>A) (P=0.011, HR: 0.74, 95%CI: 0.58-0.93) at the ULK1 gene and rs1864183 (G>A) (P=0.016, HR: 0.42, 95%CI: 0.21-0.85) at the ATG10 gene were associated with OS. Thus, the study demonstrated that the autophagy pathway might play important role(s) in platinum-based chemotherapy. DNA polymorphisms in its component genes can potentially be predictors for clinical responses of platinum-based chemotherapy among the patients with non-small lung cancer.

Exceptionally Robust In-Based Metal-Organic Framework for Highly Efficient Carbon Dioxide Capture and Conversion.

An In-based metal-organic framework, with 1D nanotubular open channels, In2(OH)(btc)(Hbtc)0.4(L)0.6·3H2O (1), has been synthesized via an in situ ligand reaction, in which 1,2,4-H3btc is partially transformed into the L ligand. Compound 1 exhibits exceptional thermal and chemical stability, especially in water or acidic media. The activated 1 presents highly selective sorption of carbon dioxide (CO2) over dinitrogen. Interestingly, diffuse-reflectance infrared Fourier transform spectroscopy with a carbon monoxide probe molecule demonstrates that both Lewis and Brønsted acid sites are involved in compound 1. As a result, as a heterogeneous Lewis and Brønsted acid bifunctional catalyst, 1 possesses excellent activity and recyclability for chemical fixation of CO2 coupling with epoxides into cyclic carbonates under mild conditions. In addition, the mechanism for the CO2 cycloaddition reaction has also been discussed.

Orientation hydrogen-bonding effect on vibronic spectra of isoquinoline in water solvent: Franck-Condon simulation and interpretation.

The excited-state orientation hydrogen-bonding dynamics, and vibronic spectra of isoquinoline (IQ) and its cationic form IQc in water have been investigated at the time-dependent density functional theory quantum chemistry level plus Franck-Condon simulation and interpretation. The excited-state orientation hydrogen bond strengthening has been found in IQ:H2O complex due to the charge redistribution upon excitation; this is interpreted by simulated 1:1 mixed absorption spectra of free IQ and IQ:H2O complex having best agreement with experimental results. Conversely, the orientation hydrogen bond in IQc:H2O complex would be strongly weakening in the S1 state and this is interpreted by simulated absorption spectra of free IQc having best agreement with experimental results. By performing Franck-Condon simulation, it reveals that several important vibrational normal modes with frequencies about 1250 cm-1 involving the wagging motion of the hydrogen atoms are very sensitive to the formation of the orientation hydrogen bond for the IQ/IQc:H2O complex and this is confirmed by damped Franck-Condon simulation with free IQ/IQc in water. However, the emission spectra of the IQ and IQc in water have been found differently. Upon the excitation, the simulated fluorescence of IQ in water is dominated by the IQ:H2O complex; thus hydrogen bond between IQ and H2O is much easier to form in the S1 state. While the weakened hydrogen bond in IQc:H2O complex is probably cleaved upon the laser pulse because the simulated emission spectrum of the free IQc is in better agreement with the experimental results.

Robust molecular bowl-based metal-organic frameworks with open metal sites: size modulation to increase the catalytic activity.

Herein, two stable lead(II) molecular-bowl-based metal-organic frameworks and their micro- and nanosized forms with open metal sites were presented. These materials could act as Lewis acid catalysts to cyanosilylation reaction. Moreover, the catalytic performances are size-dependent, with the catalyst with nanosized form being 1 order of magnitude more efficient than those with micro- and millisized forms.

[Exploration on human blood type case in teaching practice of genetics].

Blood type, which harbors abundant genetics meaning, is one of the most common phenotypes in human life. With the development of science and technology, its significance is unceasingly updated and new finding is increasingly emerging, which constantly attracts people to decipher the heredity mechanism of blood type. In addition to four main associated contents, i.e., Mendelian inheritance, genetic linkage, gene mutations, and chromosome abnormalities, the blood type case also covers many other aspects of the genetics knowledge. Based on the genetic knowledge context, we can interest the students and improve the teaching output in genetic teaching practice by combining with explaining ABO blood type case and heredity mechanism, expanding leucocyte groups, and introducing infrequent blood type such as Bombay blood, Rh and MN. By carrying out the related experimental teaching, we could drive the student to integrate theory with practice. In genetic experimental teaching, 80% of the students chose this optional experiment, molecular identification of ABO blood type, and it greatly interested them. Using appropriate blood type case in teaching related knowledge, organizing PPT exhi-bition and the debating discussion activities, it could provide opportunities for student to propose their own opinions, guide the student to thinking deeply, and develop their abilities to analyze and solve problem. Afterwards, students will gain in-depth comprehension about the fundamental knowledge of genetics.

[Duplex genotyping of CYP2C19*2 and CYP2C19*3 by high-resolution melting curve analysis].

Clopidogrel is a widely used anti-platelet agent for the prevention of arterial thrombosis. It has been suggested that clopidogrel may be less effective in inhibiting platelet aggregation among patients who are carriers of CYP2C19*2 and CYP2C19*3, two loss-of-function CYP2C19 alleles, which are associated with reduced conversion of clopidogrel to its active metabolite. The objective of this research was to develop a simple and accurate method for genotyping of CYP2C19*2 and CYP2C19*3 simultaneously in one closed-tube using high-resolution melting curve (HRM) analysis. Two amplicons bracketing CYP2C19*2 and CYP2C19*3 gene variants were designed, and AT- or GC-rich 5' tails were added to selected primers to ensure two different amplicons with non-overlapping melting curves. Sixty-four random DNA samples were all fast and sensitively genotyped by HRM analysis. This method was validated by DNA sequencingtechnique, and genotypes obtained using the HRM approach perfectly matched the genotypes obtained by DNA sequencing technique. Therefore, this HRM-based assay allows simple and accurate duplex genotyping of CYP2C19*2 and CYP2C19*3 simultaneously in one closed-tube. This method is expected to be applied in clinical laboratory to guide indi-vidual dosage design of clopidogrel.

[A comparison study of glaucoma drainage implant with three different of tube coverages].

OBJECTIVE: To evaluate the efficacy and complication of glaucoma drainage implant surgery with scleral graft, scleral flap and artificial biological dural graft as the tube coverage. METHODS: Thirty-five cases (35 eyes) with refractory glaucoma who underwent FP-7 Ahmed glaucoma drainage implantation from January 2009 to June 2011 were retrospectively studied. Kaplan-Meier survival curve was applied to analyze the probability of success rate of three different tube coverage, the log-rank test used to compare the difference between tubes, and Cox proportional hazards regression analysis performed to predict the risk factors for failure. RESULTS: Conjunctival shrink back leading to exposure of tube coverage occurred in 6 eyes in artificial biological dural graft group. Intraocular pressure (IOP) elevation by encapsulated cystic blebs around the plate was seen in scleral flap group (2 eyes) and scleral graft group (1 eyes), respectively. The drainage tube exposure occurred in 1 eye in scleral graft group. Kaplan-Meier survival curve analysis showed that the success rate was 8/10, 3/9 and 14/16 in scleral graft group, artificial biological dural graft group and scleral flap group, respectively, at 12 month and 15 month. There was a significant difference among three groups (P = 0.009). The proportional hazards regression showed that artificial biological dural graft was statistically significant risk factors for failure (HR = 10.844, P = 0.015). Compared with pre-operation, the post-operative mean IOP was significantly decreased in all three groups. Postoperative IOP was not significantly different among three groups in different follow-up time point (F = 0.028 - 1.218, P > 0.05). CONCLUSIONS: Both of scleral flap group and scleral graft group are comparable in the efficacy and complication of glaucoma drainage implant surgery and have a high success rate. However, artificial biological dural graft has poor compatibility with conjunctiva resulting in severe complications, which is not recommended to be used in glaucoma drainage implant surgery.

Hydrogen-Bonded Organic Framework-Polyoxometalate-Based System for Electrochromic Devices.

A porous hydrogen-bonded organic framework (HOF) structure was explored for the first time in the design of high-performance electrochromic devices (ECDs) using polyoxometalate (POM)-based charge-balancing layers as counter electrodes (CEs). The novelty of this work lies in the facile construction of films using small molecule-based EC materials to form a porous HOF structure. A full-cell model of an ECD was constructed by utilizing a POM-based CE to optimize the voltage distribution on the HOF-coated working electrode (WE). The addition of PW12O403- (PW12) on CE significantly enhanced the voltage distribution on EC electrodes and decreased the overvoltage on the WE, further preventing the formation of non-EC species and resulting in a 3.3-fold increase in the lifetime of the ECD. The optical contrast was enhanced from 47% (TiO2 only) to 68%, and the coloration efficiency was enhanced from 185 (TiO2 only) to 373 cm2 C-1. The optimized voltage distribution on the WE, leading to the fast response time and high optical EC contrast, could be explained by the charge-balancing effect. Overall, this new finding provides a robust framework for designing high-performance ECDs, taking advantage of the porous morphology and potential matching of the HOF and PW12.

MicroRNA-125b functions as a tumor suppressor in hepatocellular carcinoma cells.

MicroRNAs (miRNAs) are important regulators of multiple cellular processes, and the deregulation of miRNA is a common event in diverse human diseases, particularly cancer. However, the mechanisms underlying the relationship between disordered miRNA expression and tumorigenesis have remained largely unknown. In this study, we demonstrated the down-regulation of miR-125b in hepatocellular carcinoma (HCC) tissues and HCC cell lines by Northern blot and quantitative RT-PCR analyses. The ectopic expression of miR-125b reduced the cellular proliferation and cell cycle progression of HCC cells by targeting Mcl-1 and IL6R. Furthermore, the miR-125b-induced inhibition of cell proliferation was rescued by the expression of Mcl-1 or IL6R variants that lacked 3' UTRs. Thus, this study revealed the differential expression of miR-125b in HCC cells and elucidated its potential as a tumor suppressor in HCC development.

Abnormal BMI in Male and/or Female Partners Are Deleterious for Embryonic Development and Pregnancy Outcome During ART Process: A Retrospective Study.

Objective: To investigate the effect of BMI in male and/or female partners on embryo development and clinical pregnancy outcome during ART. Methods: Data of 11,130 cycles between January 2018 and December 2020 were retrospectively analyzed. They were divided into Group A, B, C, and D based on couples' BMI values, also were divided into Group I, II, III and IV in IVF cycles and Group i, ii, iii, and iv in ICSI cycles. After grouping, inter-group indicators comparisons and logistic regression analysis were performed. Results: In IVF cycles, CPR in Group I and Group III were higher than Group IV. In Group III, it was higher than Group II. The AR in Group IV was higher, but the LBR was lower than Group I, Group II, and Group III. Logistic regression analysis results suggested that AR in Group IV was higher than that in Group I in IVF cycles, whereas LBR was lower.In ICSI cycles, high-quality embryo rate in Group i and Group ii were both higher than that in Group iii and Group iv. The CPR in Group i was higher than Group ii and Group iv, and in Group iii was higher than Group ii and Group iv. The AR in Group i was lower than Group iii and Group iv, and AR in Group ii was lower than Group iv. LBR, in Group I it was higher than Group ii, Group iii, and Group iv. Logistic regression analysis results suggested CPR in Group ii was significantly lower than that in Group i. AR in Group iii was considerably higher than that in Group i. LBR in Group ii and Group iv were significantly lower than that in Group i. Conclusion: Female higher BMI was not conducive to the formation of high-quality embryos in ICSI cycle. Female and/or male BMI affected AR and LBR more than CPR not only in IVF cycles, but also in ICSI cycles.

[Clinical evaluation of gingival composite resin restoring cervical defects in anterior teeth].

OBJECTIVE: To evaluate the clinical effects of gingival composite resin used for restoring cervical defects in anterior teeth. METHODS: Eighty cervical defects of anterior teeth were involved. Firstly, they were restored with simulated restorations using only tooth colored composite resin. Then, the simulated restorations were removed and the defects were restored with simulated restorations using gingival composite resin combined with tooth colored composite resin. Visual analogue scale (VAS) was employed to survey the patient satisfaction with the esthetic results of the two methods. The defects were filled with gingival composite resin and tooth colored composite resin.Then, longitudinal clinical evaluation were made at 1-week, 6-month, 1-year and 2-year recalls respectively using modified United States Public Health Service (USPHS) criteria. RESULTS: Simulated restorations made of gingival composite resin and tooth colored composite resin obtained more satisfaction in overall impression, gingival position and tooth contour than simulated restorations simply made of tooth colored composite resin (P<0.1). In the longitudinal clinical evaluation, no significant differences among the recalls were found in color match,restoration morphology, marginal adaptation, marginal discoloration, secondary caries or pulp sensitivity (P>0.1). CONCLUSION: Using gingival composite resin in restoring cervical defects in anterior teeth achieved not only satisfactory treatment effect but also ideal esthetic results.

Four-lncRNA immune prognostic signature for triple-negative breast cancer Running title: Immune lncRNAs predict prognosis of TNBC.

OBJECTIVE: We aimed to explore key immune-related long non-coding RNAs (lncRNAs) and their effect in predicting of prognosis of triple-negative breast cancer (TNBC). METHODS: Four datasets of TNBC were downloaded from TCGA and GEO databases. ImmPort database was utilized to acquire immune-related mRNAs. Single sample gene set enrichment analysis (ssGSEA) and correlation analysis were utilized to screen immune-related lncRNAs. Univariate and multivariate Cox regression analyses were utilized to screen independent prognostic lncRNAs to establish prognostic risk model, and the model was evaluated by survival analysis and nomogram. Differential functions and immune cells infiltration in high and low risk group were analyzed by Gene set variation analysis and ssGSEA. Finally, competitive endogenous RNAs was constructed. RESULTS: We revealed 62 immune-related lncRNAs, of which four lncRNAs (RP11-890B15.3, RP11-1024P17.1, MFI2-AS1 and RP11-180N14.1) had independent prognostic value. These four lncRNAs-based prognostic risk model could stratify the TNBC patients into high and low risk groups, and patients with high risk displayed unfavorable outcomes. Nomogram indicated that the prognostic model could indicate TNBC patients survival very well. We further found that high risk group showed significantly enriched immune response to tumor cell, humoral immune response and high infiltrating abundance of regulatory T cell, Type 2 T helper cell, eosinophil, etc. LncRNAs RP11-180N14.1, RP11-1024P17.1 and RP11-890B15.3 regulated more mRNAs by targeting various miRNAs. While MFI2-AS1 regulated three mRNAs by sponging miR-3150a-3p. CONCLUSION: These four lncRNAs were prognostic biomarkers and could be possible therapeutic targets in TNBC.

The applications and prospects of hydrophobic metal-organic frameworks in catalysis.

In recent years, large numbers of hydrophobic/superhydrophobic metal-organic frameworks (MOFs) have been developed. These hydrophobic MOFs not only retain rich structural variety, highly crystalline frameworks, and uniform micropores, but they also have lower affinity towards water and boosted hydrolytic stability. Until now, there were two main strategies to prepare hydrophobic MOFs, including a one-step method and post-synthesis modification (PSM). PSM was an often-used strategy for preparing hydrophobic MOFs. Hydrophobic MOFs showed unique advantages when used as catalysts for various categories of reactions. Herein, recent research advances relating to hydrophobic MOFs in the catalytic field are presented. The catalytic activities of hydrophobic MOFs and corresponding hydrophilic ones are also compared, and the superiority of hydrophobic MOFs or MOF materials as catalysts in 10 reactions is discussed. Finally, the advantages of hydrophobic MOFs as catalysts or auxiliary materials are summarized and promising future developments of hydrophobic MOFs are highlighted.

A longitudinal fixel-based analysis of white matter alterations in patients with Parkinson's disease.

INTRODUCTION: Disruption to white matter pathways is an important contributor to the pathogenesis of Parkinson's disease. Fixel-based analysis has recently emerged as a useful fiber-specific tool for examining white matter structure. In this longitudinal study, we used Fixel-based analysis to investigate white matter changes occurring over time in patients with Parkinson's disease. METHODS: Fifty patients with idiopathic Parkinson's disease (27 men and 23 women; mean age: 61.8 ± 6.1 years), were enrolled. Diffusion-weighted imaging and clinical examinations were performed at three different time points (baseline, first follow-up [after a mean of 24±2 months], and second follow-up [after a mean of 40 ± 3 months]). Additional 76 healthy control subjects (38 men and 38 women; mean age: 62.3 ± 5.5 years) were examined at baseline. The following fixel-based metrics were obtained: fiber density (FD), fiber bundle cross-section (FC), and a combined measure of both (FDC). Paired comparisons of metrics between three different time points were performed in patients. Linear regression was implemented between longitudinal changes of fixel-based metrics and the corresponding modifications in clinical parameters. A family-wise error corrected p < 0.05 was considered statistically significant. RESULTS AND DISCUSSIONS: Early degeneration in the splenium of corpus callosum was identified as a typical alteration of Parkinson's disease over time. At follow-up, we observed significant FDC reductions compared with baseline in white matter, noticeably in corpus callosum; tapetum; cingulum, posterior thalamic radiation, corona radiata, and sagittal stratum. We also identified significant FC decreases that reflected damage to white matter structures involved in Parkinson's disease -related pathways. Fixel-based metrics were found to relate with a deterioration of 39-item Parkinson's Disease Questionnaire, Unified Parkinson's Disease Rating Scale and activity of daily living. A Parkinson's disease -facilitated aging effect was observed in terms of white matter disruption. CONCLUSION: This study provides a thorough fixel-based profile of longitudinal white matter alterations occurring in patients with Parkinson's disease and new evidence of FC as an important role in white matter degeneration in this setting.

Optimal interval from decompression to semi-elective operation in sigmoid volvulus.

BACKGROUND/AIMS: The initial non-operative decompression and subsequent semi-elective operation is a common strategy in managing sigmoid volvulus. However, the optimal interval between decompression and operation is still unclear. METHODOLOGY: From 1994 to 2004, 25 patients operated on for sigmoid volvulus at the National Taiwan University Hospital were enrolled. The treatment strategy and clinical outcome in these patients were retrospectively reviewed and analyzed. RESULTS: Twenty-one patients underwent successful non-operative decompression initially, and the remaining 4 patients underwent emergent operation. Gangrene of the colon was found in 3 patients, and all of them eventually died of medical complications, i.e. multiple organ failure, pneumonia and myocardial infarction. One leakage but no mortality occurred in the patients undergoing semi-elective operation. The rate of postoperative complication was not significantly different between the patients operated on 2 days and more than 2 days after the decompression. CONCLUSIONS: The initial non-operative decompression and subsequent semi-elective operation results in a satisfactory outcome in managing sigmoid volvulus. In the view of surgical result, a two-day interval seems adequate for bowel preparation and optimization of the patient's condition.

IFIT1 polymorphisms predict interferon-α treatment efficiency for hepatitis B virus infection.

AIM: To investigate the association between interferon-induced protein with tetratricopeptide repeats 1 (IFIT1) polymorphisms and interferon-α (IFNα) treatment efficiency among Chinese hepatitis B virus (HBV) infection patients. METHODS: Two hundred and twenty five newly diagnosed chronic hepatitis B (CHB) patients were enrolled in the study. All of these patients received IFNα treatment for a course of 48 wk, and were followed up for 24 wk after the treatment was end. Clinical information about virological response, hepatitis B e antigen (HBeAg) seroconversion rate and combined response at the end of the treatment, as well as the sustained response by the time of following up 24 wk after the treatment, was collected. Four tag-single nucleotide polymorphisms (SNPs) of IFIT1 were selected and assessed for their association with these clinical outcomes. RESULTS: At the end of the treatment, HBeAg seroconversion was observed in 27.1% patients. Thirty-six point nine percent patients achieved virological response, and 15.6% patients exhibited combined response. Sustained response was obtained in 26.2% patients. The main HBV genotype of the study was genotype B. Patients who infected with HBV genotype B or C showed better treatment efficiency, no matter which clinical outcome was considered. Among the four SNPs assessed, rs303218 (A > G) was found to be significantly associated with the end point virological response when assuming additive model [OR = 0.64 (95%CI: 0.42-0.96), P = 0.032]. Patients who carried rs303218 GG genotype had a rather higher rate of achieving virological response (response rate: 52%, OR = 0.40, 95%CI: 0.18-0.91; P = 0.028) when compared to those had AA genotype (response rate: 27%). The most significant interaction was observed in patients who had relative lower baseline aspartate transaminase. No association between SNPs and HBeAg seroconversion, combined response or sustained response was observed. CONCLUSION: IFIT1 involves in the regulation of IFNα treatment for CHB and its polymorphism rs303218 can predict the end point virological response. The finding requires further validation.

Study on the synergetic degradation of chitosan with ultraviolet light and hydrogen peroxide.

Chitosan was effectively degraded by hydrogen peroxide under irradiation with ultraviolet light. The existence of a synergetic effect on the degradation was demonstrated by means of viscometry. In addition, the optimal conditions of degradation were determined on the basis of orthogonal tests. The structure of the degraded product was characterized by Fourier-transform infrared spectra (FTIR) analysis and diffuse reflectance spectra (DRS) analysis. The mechanism of the degradation of chitosan was correlated with cleavage of the glycosidic bond.

Vitreoscilla hemoglobin promotes Salecan production by Agrobacterium sp. ZX09.

Salecan is a novel exopolysaccharide produced by the strain Agrobacterium sp. ZX09, and it is composed of only glucose monomers. The unique chemical composition and excellent physicochemical properties make Salecan a promising material for applications in coagulation, lubrication, protection against acute liver injury, and alleviating constipation. In this study, we cloned the Vitreoscilla hemoglobin gene into a broad-host-range plasmid pCM158. Without antibiotic selection, there was negligible loss of the plasmid in the host Agrobacterium sp. ZX09 after one passage of cultivation. The expression of Vitreoscilla hemoglobin was demonstrated by carbon monoxide (CO) difference spectrum. The engineered strain Agrobacterium sp. ZX09 increased Salecan yield by 30%. The other physiological changes included its elevated respiration rate and cellular invertase activity.