Impacts of silver nanoparticles on performance and microbial community and enzymatic activity of a sequencing batch reactor.

The performance, microbial community and enzymatic activity of a sequencing batch reactor (SBR) were evaluated under silver nanoparticles (Ag NPs) stress. Over 5 mg/L Ag NPs inhibited the COD and phosphorus removals, whereas the NH4+ removal kept stable during the whole operational period. The organic matter, nitrogen and phosphorus removal rates were obviously inhibited under Ag NPs stress, which showed similar varying trends with the corresponding microbial enzymatic activities. The change of Ag content in the activated sludge indicated that some Ag NPs were absorbed by the sludge. The presence of Ag NPs promoted the increase of reactive oxygen species (ROS) and lactate dehydrogenase (LDH) of microorganism due to the microbial response to the Ag NPs toxicity, which could impact on the microbial morphology and physiological functions. The presence of Ag NPs could produce some evident changes in the microbial community.

[Study on the Spectral Characteristics of Xeon Flash Lamp and Experimental Measurement].

Xenon flash lamp is used by most analytical instruments and medical equipments as light sources whose spectral characteristics exert a tremendous influence on the property of instruments and medical equipments. In order to study the effects of pulsed Xenon discharge circuit parameters and geometric parameters on the spectral characteristics, theoretical analysis has been conducted to Xenon lamp emitting process with the gas discharge theory. The spectroscopic detection system has been designed to conduct experimental detection to the spectral characteristics of pulsed Xenon lamp with different parameters. The experimental results show that the emission spectra of Xenon flash lamp contain both line and continuous radiation. The line spectrum results from the electron energy gap transition, while the cw radiation related to ionic recombination and bremsstrahlung. The relative spectral intensity increases linearly with the discharge voltage, and has a positive correlation with storage capacitor. When low discharge voltage, the shorter the arc length, the higher the relative spectral intensity .while the discharge voltage becomes higher, the result is reversed. The work in this paper has great significance for xenon flashlamp on the parameters selection and industrial application.

Aspect Ratio Modulation of Sucralose through {002}/{011} Preferred Orientation in Antisolvent Crystallization.

The aspect ratio modulation in the alcoholysis process is highly significant for the production of high-quality sucralose. In this work, antisolvent crystallization (ASC) accompanied by preferred orientation was first adopted in the sucralose separation, based on which simultaneous modulations on aspect ratio, solubility, and stability have been realized. In detail, after the alcoholysis process in methanol, four antisolvents bearing different functional groups were used in ASC, i.e., isopentanol (IPN), isovaleraldehyde (IVD), isovaleric acid (IVA), and isobutyl propionate (IBP). To our interest, when IVA was used as the antisolvent, the highest separation efficiency (49.33%), fastest crystallizing rate (5.64%/h), lowest aspect ratio (1.55), and solubility (9.28 wt %) and good thermal stability (131.65 °C) of sucralose were achieved. Single crystal structures of sucralose using different antisolvents have been determined. Sucralose using IVA as the antisolvent exhibits the greatest molecular distortion and strongest intermolecular C-H···Cl hydrogen bonds; thus, the preferred growth along {002}/{011} directions has occurred and accounted for its lower aspect ratio, worse solubility, and better stability. The strongest methanol···IVA interactions due to the presence of a carboxyl group can accelerate the formation of the emulsion, resulting in the fastest crystallizing rate. The antisolvent screening and the discovery about relative mechanisms will provide a theoretical guide for the production of high-quality sucralose.

Association between intrahepatic triglyceride content in subjects with metabolically healthy abdominal obesity and risks of pre-diabetes plus diabetes: an observational study.

OBJECTIVE: We aimed to evaluate the association of intrahepatic triglyceride (IHTG) content in subjects with metabolically healthy abdominal obesity (MHAO) on risks of pre-diabetes plus diabetes. DESIGN: Cross-sectional survey. SETTING: Lianqian community, the First Affiliated Hospital of Xiamen University, Xiamen, China. PARTICIPANTS: Among 1523 community-living healthy adults aged 40 years or older with abdominal obesity recruited at baseline, 428 subjects who underwent IHTG content measurement were selected. OUTCOME MEASURES: Risk of pre-diabetes plus diabetes. RESULTS: Non-alcoholic fatty liver disease (NAFLD) was diagnosed as 203 (69.1%) in MHAO and 121 (90.3%) in metabolically unhealthy abdominal obesity (MUAO) (p<0.001). The prevalence rates of pre-diabetes plus diabetes were 81.1%, 88.8% and 90.9% across the tertiles of IHTG content (p=0.037). Both MUAO (vs MHAO) and NAFLD (vs non-NAFLD) were independently associated with increased risks of pre-diabetes plus diabetes, the adjusted ORs (95% CIs) were 10.90 (3.15 to 37.69, p<0.001) and 3.02 (1.47 to 6.20, p=0.003), respectively. Higher IHTG content was significantly associated with increased risk of pre-diabetes plus diabetes with the adjusted OR (95% CI) of per SD increase of IHTG content of 1.62 (1.07 to 2.46, p=0.024). And there was a significantly positive trend between increasing categories of IHTG content tertiles and excessive risks of pre-diabetes plus diabetes (trend test p value=0.011). Stratified analyses showed similar results on the associations of NAFLD and IHTG content with risks of pre-diabetes plus diabetes for subjects with MHAO but not for those with MUAO. CONCLUSIONS: NAFLD and higher IHTG content were independently associated with increased risks of pre-diabetes plus diabetes in MHAO subjects. NAFLD or quantity of liver fat should be considered as additional criterion when defining and diagnosing MHO. Screening of NAFLD and intervention to reduce liver fat should be strengthened even for those seemly metabolically healthy obese.

Joint associations of metabolically healthy abdominal obesity and non-alcoholic fatty liver disease with prediabetes and diabetes in Chinese adults.

INTRODUCTION: We aimed to evaluate the joint associations of metabolically healthy abdominal obesity (MHAO) with non-alcoholic fatty liver disease (NAFLD) on risks of diabetes and prediabetes. RESEARCH DESIGN AND METHODS: Baseline information of 1318 adults with abdominal obesity (waist circumference ≥90 cm for men and 80 cm for women) from an ongoing cohort study in Xiamen, China were analyzed. Metabolic health was identified as none of the criteria of metabolism syndrome, except for obesity, was met. RESULTS: MHAO and metabolically unhealthy abdominal obesity (MUAO) were identified on 173 (13.1%) and 1145 (86.9%) subjects. NAFLD was further diagnosed on 60 (34.7%) in MHAO and 721 (63.0%) in MUAO groups (p<0.001). Both MUAO (vs MHAO) and NAFLD (vs non-NAFLD) were independently associated with increased risks of diabetes as well as prediabetes plus diabetes, with the adjusted ORs (95% CIs) of 9.40 (3.38 to 26.14) and 2.02 (1.47 to 2.77), respectively. Compared with MHAO and non-NAFLD, MHAO and NAFLD showed significantly increased risks of prediabetes plus diabetes with the adjusted ORs (95% CIs) of 2.87 (1.32 to 6.27, p=0.008). And there were significantly positive trends between increasing categories jointly by MHAO and NAFLD (from MHAO and non-NAFLD, MHAO and NAFLD, MUAO and non-NAFLD to MUAO and NAFLD) with risks of diabetes and prediabetes plus diabetes (both trend tests: p<0.001). CONCLUSIONS: About 35% of subjects with MHAO accompanied by NAFLD showed excessive risk of prediabetes plus diabetes compared with MHAO and non-NAFLD. Thus, NAFLD should be screened and intervened even for those subjects with metabolically healthy obesity (MHO) and should be considered as one additional criterion when defining and diagnosing MHO.

Performance evaluation and microbial community shift of a sequencing batch reactor under silica nanoparticles stress.

The performance, microbial community and enzymatic activity of a sequencing batch reactor (SBR) were evaluated at different silica nanoparticles (SiO2 NPs) concentrations. SiO2 NPs concentration at 5-30mg/L had a slight inhibitory impact on the nitrogen and COD removals, whereas the phosphorus removal was obviously inhibited at 30mg/L SiO2 NPs. The rates of nitrification, nitrite reduction and phosphorus removal decreased with the increase of SiO2 NPs concentration. The nitrate reduction rate decreased at less than 5mg/L SiO2 NPs and subsequently showed an increase at 10-30mg/L SiO2 NPs. The organic matter, nitrogen and phosphorus removal rates had similar varying tendencies to the corresponding microbial enzymatic activities under SiO2 NPs stress. Some SiO2 NPs were firstly absorbed on sludge surface and subsequently entered the interior of the microbial cells, which could exert the biological toxicity to activated sludge. The microbial community showed some obvious variations under SiO2 NPs stress.

Long-term impacts of titanium dioxide nanoparticles (TiO2 NPs) on performance and microbial community of activated sludge.

The long-term impacts of titanium dioxide nanoparticles (TiO2 NPs) on the performance and microbial community of activated sludge were evaluated in a sequencing batch reactor (SBR). TiO2 NPs impacted the COD and phosphorus removals of activated sludge, whereas the NH4+-N removal efficiency had no distinct change at 0-60mg/L TiO2 NPs. The presence of TiO2 NPs obviously inhibited the organic matter and nitrogen removal rates of activated sludge. The phosphorus removal rate gradually reduced at 0-5mg/L TiO2 NPs and then increased at 10-60mg/L TiO2 NPs. The removal rates of organic matter, nitrogen and phosphorus had the similar varying trends to the corresponding microbial enzymatic activities. High TiO2 NPs concentration promoted more reactive oxygen species (ROS) production and lactate dehydrogenase (LDH) release of activated sludge. The microbial richness and diversity of activated sludge were obviously affected at the phyla, class and genus levels.

Impact of sulfadiazine on performance and microbial community of a sequencing batch biofilm reactor treating synthetic mariculture wastewater.

The impact of sulfadiazine on the performance, microbial activity and microbial community of a sequencing batch biofilm reactor (SBBR) were evaluated in treating mariculture wastewater due to the application of sulfadiazine as an antibiotic in mariculture. The COD and nitrogen removals kept stable at 0-6mg/L sulfadiazine and were inhibited at 10-35mg/L sulfadiazine. The microbial activities related to organic matter and nitrogen removals reduced with an increase in sulfadiazine concentration. The presence of sulfadiazine could affect the production and chemical composition of loosely bound extracellular polymeric substances (LB-EPS) and tightly bound EPS (TB-EPS) in the biofilm. High-throughput sequencing demonstrated that sulfadiazine could impact on the microbial richness and diversity of SBBR treating mariculture wastewater. The relative abundances of Nitrosomonas, Nitrospira, Paracoccus, Hyphomicrobium, Rhodanobacter, Thauera and Steroidobacter decreased with an increase in sulfadiazine concentration, indicating that the presence of sulfadiazine decreased the relative abundance of some nitrifying and denitrifying bacteria.

[Improving maltodextrin specificity by site-saturation engineering of subsite +1 in cyclodextrin glycosyltransferase from Paenibacillus macerans].

By engineering the subsite +1 of cyclodextrin glycosyltransferase (CGTase) from Paenibacillus macerans, we improved its maltodextrin specificity for 2-O-D-glucopyranosyl-L-ascorbic acid (AA-2G) synthesis. Specifically, we conducted site-saturation mutagenesis on Leu194, Ala230, and His233 in subsite +1 separately and gained 3 mutants L194N (leucine --> asparagine), A230D (alanine --> aspartic acid), and H233E (histidine --> glutamic acid) produced higher AA-2G yield than the wild-type and the other mutant CGTases. Therefore, the 3 mutants L194N, A230D, and H233E were further used to construct the double and triple mutations. Among the 7 obtained combinational mutants, the triple mutant L194N/A230D/H233E produced the highest AA-2G titer of 1.95 g/L, which was increased by 62.5% compared with that produced by the wild-type CGTase. Then, we modeled the reaction kinetics of all the mutants and found a substrate inhibition by high titer of L-AA for the mutants. The optimal temperature, pH, and reaction time of all the mutants were also determined. The structure modeling indicated that the enhanced maltodextrin specificity may be related with the changes of hydrogen bonding interactions between the side chain of residue at the three positions (194, 230 and 233) and the substrate sugars.

Improving maltodextrin specificity for enzymatic synthesis of 2-O-d-glucopyranosyl-l-ascorbic acid by site-saturation engineering of subsite-3 in cyclodextrin glycosyltransferase from Paenibacillus macerans.

In this work, the subsite-3 of cyclodextrin glycosyltransferase (CGTase) from Paenibacillus macerans was engineered to improve maltodextrin specificity for 2-O-d-glucopyranosyl-l-ascorbic acid (AA-2G) synthesis. Specifically, the site-saturation mutagenesis of tyrosine 89, asparagine 94, aspartic acid 196, and aspartic acid 372 in subsite-3 was separately performed, and three mutants Y89F (tyrosine→phenylalanine), N94P (asparagine→proline), and D196Y (aspartic acid→tyrosine) produced higher AA-2G titer than the wild-type and the other mutants. Previously, we found the mutant K47L (lysine→leucine) also had a higher maltodextrin specificity. Therefore, the four mutants K47L, Y89F, N94P, and D196Y were further used to construct the double, triple, and quadruple mutations. Among the 11 combinational mutants, the quadruple mutant K47L/Y89F/N94P/D196Y produced the highest AA-2G titer of 2.23g/L, which was increased by 85.8% compared to that produced by the wild-type CGTase. The reaction kinetics of all the mutants were modeled, and the pH and thermal stabilities of all the mutants were analyzed. The structure modeling indicated that the enhanced maltodextrin specificity may be related with the changes of hydrogen bonding interactions between the side chain of residue at the four positions (47, 89, 94, and 196) and the substrate sugars.

The sagittal curving osteotomy: a modified technique for advancement genioplasty.

PURPOSE: The purpose of the present study was to develop a new type of osteotomy for advancement genioplasty to decrease the incidence of neurosensory disturbance of the chin. PATIENTS AND METHOD: Forty-six patients who suffered from a slight or moderate degree of microgenia received a sagittal curving osteotomy for advancement genioplasty. Patients were followed for 1-6 months to assess the neurosensory function of the chin region by evaluating light-touch perception. The control group, 57 patients, who suffered from the same degree of microgenia, received a horizontal sliding osteotomy. They were operated on by the same surgical group and were followed for 1-33 months. RESULTS: All of the test and control patients were satisfied with the aesthetic results of the surgery. In the test group, 47 sides (51.87%) of 92 total left and right sides of chins had a transient neurosensory deficiency but none had permanent neurosensory deficiency. In the control group, 98 sides (86.84%) of 114 total chin sides had a transient neurosensory deficiency and five sides (4.43%) of 114 total chin sides had permanent neurosensory deficiency. When applied to patients who suffer from a mild or moderate degree of microgenia and have normal bite function, the sagittal curving osteotomy is a simple, safe and effective technique for advancement genioplasty. This technique can distinctively decrease the incidence of neurosensory disturbance of the chin.