Geobacter sulfurreducens promoted the biosynthesis of reduced graphene oxide and coupled it for nitrobenzene reduction.

In order to explore an efficient and green method to deal with nitrobenzene (NB) pollutant, reduced graphene oxide (rGO) as an electron shuttle was applied to enhance the extracellular electron transfer (EET) process of Geobacter sulfurreducens, which was a typical electrochemically active bacteria (EAB). In this study, rGO biosynthesis was achieved via the reduction of graphene oxide (GO) by G. sulfurreducens PCA within 3 days. Also, the rGO-PCA combining system completely reduced 50-200 µmol/L of NB to aniline as end product within one day. SEM characterization revealed that PCA cells were partly wrapped by rGO, and therefore the distance of electron transfer between strain PCA and rGO material was reduced. Beside, the ID/IG of GO, rGO, and rGO-PCA combining system were 0.990, 1.293 and 1.31, respectively. Moreover, highest currents were observed in rGO-PCA-NB as 12.950 µA/-12.560 µA at -408 mV/156 mV, attributing to the faster electron transfer efficiency in EET process. Therefore, the NB reduction was mainly due to: (I) direct EET process from G. sulfurreducens PCA to NB; (II) rGO served as electron shuttle and accelerated electron transfer to NB, which was the main degradation pathway. Overall, the biosynthesis of rGO via GO reduction by Geobacter promoted the NB removal process, which provided a facile strategy to alleviate the problematic nitroaromatic pollution in the environment.

Effects of modified biochars on the shifts of short-chain fatty acid profile, iron reduction, and bacterial community in paddy soil.

Biochar is well known as an effective means for soil amendment, and modification on biochar with different methods could improve the benefits for environmental remediation. In this study, two modified biochars were generated with nitric acid (NBC) and hydrogen peroxide (OBC) pretreatment, and a control biochar was produced after washing with deionized water (WBC). The dynamics of short-chain fatty acids (SCFAs), iron concentration and bacterial community in rice paddy soil amended with different biochars or without adding biochar (CK) were studied during 70 days of anaerobic incubation. Compared to CK treatment, the accumulation of SCFAs was largely inhibited by the amendment of biochars. Besides, OBC and WBC increased the accumulation of Fe(II) at the initial stage of incubation. Via 16S rRNA gene sequencing, modified biochars caused significant response of bacterial community in comparison to WBC at Day 0-1, and three biochars favored bacterial α-diversity in the paddy soil at the end of the incubation. Interestingly, positive and negative correlations between NBC and several bacteria taxa (e.g. Geobacter, Fonticella and Clostridium) were observed. The study revealed that modified biochars had significant effects on the shifts of SCFAs, Fe(III) reduction and bacterial diversity, which provides fundamental information for future application of modified biochars in rice cropping ecosystem.

Effect of CuO/ZnO/FTO electrode properties on the performance of a photo-microbial fuel cell sensor for the detection of heavy metals.

The development of sustainable, low-cost and responsive technology for heavy metals detection in wastewater is crucial. In this study, by combining CuO/ZnO photocathode with microbial anode, a novel photo-microbial fuel cell (PMFC) sensor was developed. The self-powered PMFC was performed under light and dark condition for heavy metals detection. Compared with MFC sensor, PMFC sensor showed a wider detection range (0.1-4 mg L-1 of Cd2+ and 10-80 mg L-1 of Cu2+). The improved performance in sensing limit and sensitivity was mainly attributed to the intimate P-N heterojunctions formed in CuO/ZnO, which accelerated the electron transport between the photocathode and the microbial anode. Besides, the toxicity of five heavy metals tested in PMFC was shown as Cd2+>Cr6+>Zn2+>Hg2+>Cu2+. This study has taken advantage of the characteristics of PMFC and facilitated its application in heavy metals detection, which provides a new approach for the development of biosensors.

Ferric chloride aiding nitrite pretreatment for the enhancement of the quantity and quality of short-chain fatty acids production in waste activated sludge.

The production of short-chain fatty acids (SCFAs) via anaerobic fermentation of waste activated sludge (WAS) is often limited with poor quality of SCFAs and long fermentation time. To overcome these issues, we provided an efficient strategy by using ferric chloride (FC) to aid nitrite pretreatment. Experimental results showed that the maximal SCFAs production of 211.3 ± 3.1 mg COD/g VS was achieved with 4 mmol/L of FC integrated with 250 mg/L of nitrite pretreatment on day 5, which was 4.1-fold higher than that of the blank control (52 ± 5 mg COD/g VS, day 7). Besides, the enrichment of acetic acid was observed in the combined system, which accounted for 54.6 ± 3.5% of total SCFAs, while the proportion was only 31.5 ± 4.9% in the blank control. Propionic acid, isobutyric acid, n-butyric acid, n-valeric acid and isovaleric acid accounted for 14.7 ± 1.5%, 6.9 ± 1.4%, 7.4 ± 1.5%, 13.1 ± 1.0%, and 3.3 ± 1.5% of total SCFAs in the combined system and 22.8 ± 4.0%, 11.9 ± 3.0%, 6.7 ± 3.1%, 17.6 ± 2.0%, and 9.5 ± 3.9% of total SCFAs in the blank control, respectively. It was found that soluble proteins and carbohydrates in the combined system were higher than those in the blank control, suggesting that FC and nitrite pretreatment was beneficial for WAS disintegration. The fluorescence spectrum results suggested that FC and nitrite pretreatment improved the biodegradability of released organics, which provided more biodegradable substances for the subsequent SCFAs production. This was because the addition of FC induced the formation of free nitrous acid from nitrite. Besides, FC-induced iron reduction also promoted the conversion of recalcitrant organics to biodegradable organic matter. Microbial community structure analysis demonstrated that the functional bacteria involved in acetogenesis process such as Enterococcus, Proteiniclasticum, and Petrimonas were highly enriched due to the pretreatment of FC and nitrite, indicating this method could improve the relative abundance of SCFAs producers. Overall, this study revealed that the pretreatment of FC and nitrite promoted the formation of free nitrous acid and increased the yield of SCFAs, which provided a novel method for wastewater treatment plants to ameliorate the sewage treatment craft and rationally use the existing substances in WAS to enhance resource recovery.

Au/CeO2/g-C3N4 heterostructures: Designing a self-powered aptasensor for ultrasensitive detection of Microcystin-LR by density functional theory.

Quantum-sized cerium dioxide (CeO2) show high catalytic capability as well as strong light absorption ability owing to its redox couple Ce4+/Ce3+ and abundant oxygen vacancies, which making it a potential material for designing superior photoelectrochemical (PEC) sensors. However, it has scarcely been applied in the field of PEC sensing, because its wide band gap and aggregation effect can restrict the photoelectric conversion efficiency. Herein, we address these two obstacles by coupling CeO2 quantum dots (QDs) with graphitic carbon nitride (g-CN) and Au nanoparticles (NPs). The electron transfer path in this proposed heterojunction was proved by density functional theory (DFT) calculation for the first time, which provided theoretical support for the detection of MC-LR. The as-obtained PEC aptasensor exhibited excellent analytical performance with a wide liner response of 0.05-105 pM, and the detection limit was 0.01 pM. By designing appropriate sensing system and specific recognition mechanism, this work may pave a unique avenue for constructing ultrasensitive and selective analysis of MC-LR in complex environment without any external electric source.

Autologous blood or autologous serum acupoint injection therapy for psoriasis vulgaris: A protocol for a systematic review and meta-analysis.

BACKGROUND: Psoriasis vulgaris (PV) is a refractory and relapsing skin disease that affects the physical and mental health of patients and leads to poor quality of life. Current conventional systemic therapy shows a large side effect, which can not be used for a long time, easy to relapse after drug withdrawal, long-term efficacy is poor. At present, traditional Chinese medicine treatment of psoriasis vulgaris effective, can alleviate symptoms, improve the quality of life, stabilize the condition, prolong the remission period. Whereas, there is no related systematic review and meta-analysis. Thus, we intend to conduct a systematic review and meta-analysis to testify autologous blood or autologous serum acupoint injection therapy for Psoriasis Vulgaris. METHODS: Our systematic review will search all randomized controlled trials for autologous blood therapy of PV, electronically and manually, regardless of publication status and language, until March 19, 2020. Databases include PubMed, EMBASE, Web of Science, Cochrane Controlled Trials Register, China National Knowledge Infrastructure, China Biomedical Literature Database, Chinese Science Journal Database, and Wanfang database. Other sources, including reference lists of identified publications and meeting minutes, will also be searched. Manually search for grey literature, including unpublished conference articles. RESULT: The main outcomes contain the variation of Psoriasis area and severity index, dermatology life quality index, itching score, the effective rate and adverse events from baseline to the end of studies. This study will provide a comprehensive review of the available evidence for the treatment of PV with this therapy. CONCLUSION: We will summarize sufficient evidence to confirm the therapeutic effect and safety of autologous blood or autologous serum acupoint injection therapy for PV. Due to the data is not individualized, formal ethical approval is not required. INPLASY REGISTRATION NUMBER: INPLASY202040052.

[MEDIUM-TERM EFFECTIVENESS OF ANTERIOR RELEASE INTERNAL DISTRACTION FOR SEVERE AND RIGID SCOLIOSIS].

OBJECTIVE: To observe the medium-term clinical and radiological outcomes of anterior release internal distraction in treatment of severe and rigid scoliosis. METHODS: Between March 2009 and March 2012, 26 patients with severe and rigid scoliosis were treated with anterior release, posterior internal distraction, and two stage posterior spinal fusion. There were 11 males and 15 females with an average age of 19.6 years (range, 14-25 years). The average disease duration was 13.6 years (range, 3-2:4 years). All cases were idiopathic scoliosis. Of 26 cases, 2 cases were rated as Lenke type I, 8 as type II, 13 as type IV, 1 as type V, and 2 as type VI. The apical vertebrae located at T6 in 1 case, at T7 in 3 cases, at T8 in 7 cases, at T9 in 13 cases, and at T10 in 2 cases. The average 4 vertebral bodies were released by anterior approach, and average 14 vertebral bodies were fused after posterior surgery. Fourteen patients received 2 times distraction. Scoliosis Research Society-22 (SRS-22) questionnaire was used to access health-related quality of life. The radiological parameters were measured, including coronal plane Cobb angel of major curve, apical vertebral translation (AVT), C7 plumb line-center sacral vertical line (C7PL-CSVL), sagittal vertical axis (SVA), and thoracic kyphosis (TK) at pre- and post-operation. Results The average total operation time was 592.7 minutes; the average total blood loss volume was 1 311.2 mL; and total hospitalization cost was (14.7±1.4)x10(4) yuan RMB. The coronal plane Cobb angle of major curve was (55.7±16.5)°, and the TK was (43.2±16.2)° after first distraction. The patients were followed up 2-5 years (mean, 3.8 years). Temporary dyspnea and pleural effusion occurred in 1 case respectively after distraction, and symptoms disappeared after symptomatic treatment. Screw loosening and pseudoarthrosis formation was observed in 1 case at 6 months after fusion, good recovery was achieved after revision. No infection or neurological complication was found. The coronal plane Cobb angel of major curve, TK, and AVT after fusion and at last follow-up were significantly lower than preoperative ones (P<0.05), but no significant difference was found between at post-fusion and last follow-up (P>0.05). There was no significant difference in C,PL-CSVL and SVA between at pre- and post-operation (P>0.05). At last follow-up, SRS-22 questionnaire scores were 4.32±0.42 for active degree, 4.54±0.58 for mental health, 3.97±0.76 for self-image, 4.09±0.64 for pain, and 4.03±0.83 for satisfaction degree. CONCLUSION: Anterior release internal distraction can provide satisfactory correction results for severe and rigid scoliosis with higher safety and lower incidence of complication.

[Progress on the cause and mechanism of a separation of clinical symptoms and signs and imaging features in lumbar disk herniation].

A few of patients with lumbar disk herniation having a separation of clinical symptoms and signs and imaging features, can be found in clinic, but the traditional theory of direct mechanical compression of nerve roots by herniated nucleus pulposus can't be used to explain this abnormal protrusion of lumbar intervertebral disc. The clinical symptoms and signs of the atypical lumbar disk herniation are affected by multiple factors. The indirect mechanical compression and distraction effect of spinal nerve roots may play an important role in the occurrence of the separation, and the appearance of abnormal clinical symptoms and signs is closely related to the migration of herniated nucleus pulposus tissue, transmission of injury information in the nervous system, and the complex interactions among the nucleus pulposus, dural sac and nerve roots. Moreover,the changes of microcirculation and inflammation secondary to the herniated nucleus pulposus tissue, the hyperosteogeny in the corresponding segment of the lumbar vertebrae and the posture changes all results in a diversity of symptoms and signs in patients with lumbar intervertebral disc herniation. Besides, there exist congenital variation of lumbosacral nerve roots and vertebral bodies in some patients, and the misdiagnosis or missed diagnosis of imaging finding may occur in some cases. However, the appearance of a separation of clinical symptoms and signs and imaging examination in patients may be caused by a variety of reasons in clinic. The exact mechanism involved in the interaction among nucleus pulposus tissue, dural sac and nerve root, secondary changes of pathophysiology and biomechanics around the nucleus pulposus, the determination of lesioned responsible segments, and how to overcome the limitations of imaging all need the further researches.