Restriction of Intramolecular Vibration in Aggregation-Induced Emission Luminogens: Applications in Multifunctional Luminescent Metal-Organic Frameworks.

Butterfly-like molecules of oxacalix[2]arene[2]pyrazine (OAP) are reported, which exhibit the typical characteristics of aggregation-induced emission (AIE) via the restriction of intramolecular vibration (RIV) mechanism. Unlike any of the reported RIV-type AIE molecules, the synthetic procedures of which are complicated and have associated high costs, OAP AIEgens can be synthesized in a facile manner by a one-step catalyst-free reaction using commercially available materials. Notably, OAP AIEgens are ideal ligands for constructing metal-organic frameworks (MOFs) due to their built-in pyrazine coordination sites. OAP-based MOFs exhibit multiple potential applications in reversible gas response, encrypted information storage, and construction of white light-emitting devices. This work builds on RIV-type AIEgens, offers additional selections of bridging ligands for constructing luminescent MOFs and provides a visualized prototype to understand the effect of the RIV process on the luminescence properties of MOFs.

Thermochromic luminescent nest-like silver thiolate cluster.

A novel discrete open high-nuclearity nest-like silver thiolate cluster complex, [Ag33 S3 (StBu)16 (CF3 COO)9 (NO3 )(CH3 CN)2 ](NO3 ) (1), has been isolated with nitrate and S(2-) anions acting as structure-directing templates. Its similar nest-like structure has been assembled into an extended layer [Ag31 S3 (StBu)16 (NO3 )9 ]n (2) by adjustment of auxiliary ligand. More interestingly, both complexes exhibit temperature-dependent luminescence of high sensitivity with a large fluorescence enhancement (12-fold for 1, 21-fold for 2), which can be easily recognized by the naked-eye (dramatic red-shift Δ=104 nm for 1, larger Δ=113 nm for 2 at 77 K compared to those at 298 K). The correlation between luminescent thermochromism and temperature-dependent variation of the coordination modes of template NO3 (-) anion, Ag⋅⋅⋅S and Ag⋅⋅⋅Ag distances are also elucidated through variable-temperature single-crystal X-ray crystal structure (VT-SCXRD) analyses.

Alkaline earth metal (Mg, Sr, Ba)-organic frameworks based on 2,2',6,6'-tetracarboxybiphenyl for proton conduction.

Three new alkaline earth metal based metal-organic frameworks (MOFs), namely M-BPTC (M = Mg, Sr, Ba), have been synthesized by using BPTC (2,2',6,6'-tetracarboxybiphenyl) as ligand under hydrothermal conditions. These MOFs exhibit interesting structural diversity, variable chemical and thermal stability, as well as proton conductivity. Mg-BPTC with the formula {[Mg(BPTC)0.5(H2O)3]·5H2O}n consists of BPTC(4-) extended metal layers, and novel highly ordered infinite tape-like structures of cyclic water octamers reside interlayer. Three-dimensional porous {[Sr2(BPTC)(H2O)6]·H2O}n (Sr-BPTC) features inorganic Sr-O chains (I(1)O(2)) and open hydrophilic channels where water heptamers and carboxyl oxygen atoms conspire to form H-bond networks, whereas 3D {[Ba6(BPTC)3(H2O)6]·11H2O}n (Ba-BPTC) shows Ba-O inorganic layer (I(2)O(1)) and 1D channels incorporating large water 14-mers and 18-mers. M-BPTC (M = Mg, Sr) species exhibit excellent water stability and proton conductivity due to their respective appropriate pathways for proton transporting. M-BPTC (M = Sr, Ba) structures are highly thermally stable due to the presence of the inorganic connectivity. The present results suggest that M-BPTC (M = Mg, Sr) are promising materials for proton conduction and provide insight into the hydrogen bonding motif.

A highly sensitive C3-symmetric Schiff-base fluorescent probe for Cd2+.

A new C3-symmetric Schiff-base fluorescent probe (L) based on 8-hydroxy-2-methylquinoline has been developed. As expected, the probe L can display high fluorescent selectivity for Cd(2+) over Zn(2+) and most other common ions in neutral ethanol aqueous medium. Moreover, the mechanism of the L-Cd(2+) complex has been confirmed by X-ray crystallography and density functional theory calculation results. More importantly, L could be used to image Cd(2+) within living cells.

Ferroelectric switchable behavior through fast reversible de/adsorption of water spirals in a chiral 3D metal-organic framework.

A polar homochiral 3D MOF [{Co2(L)(bpe)(H2O)}·5H2O]n constructed with cobalt(II) and a new ligand N-(1,3-dicarboxy-5-benzyl)-carboxymethylglycine (H4L) accommodates ordered helical water streams in its helical grooves. It provides the first example of switchable ferroelectric and optical behavior through two-step reversible single-crystal to single-crystal transformation (SCSC) upon desorption/adsorption of water spirals and coordinated water molecules, respectively.

Photocatalytic H2 generation based on noble-metal-free binuclear cobalt complexes using visible-light.

Two new binuclear cobalt complexes, namely {[Co(dmgH)(dmgH2)]2L1} (I) and {[Co(dmgH)(dmgH2)]2L2} (II) (dmgH = dimethylglyoximate monoanion; dmgH2 = dimethylglyoxime, L1 = 1,3-bis(4-pyridyl)propane), L2 = 1,3-bis(imidazol-1-ylmethyl)benzene), have been synthesized by the self-assembly of [Co(dmgH)(dmgH2)] and L1 or L2, respectively. An efficient photocatalytic system was constructed by combining a noble-metal-free cobalt complex as the catalyst with Eosin Y dye (EY(2-)) as the photosensitizer to give an efficient H2 generating system under visible-light irradiation (λ > 420 nm) using triethanolamine (TEOA) as a sacrificial electron donor. The maximum amount of H2 generated was 1013 TON for I and 1134 TON for II over a 2 h irradiation period (λ > 420 nm) under the conditions of pH 8.0, 5% TEOA (v/v), an EY(2-) concentration of 4.0 × 10(-4) M and a catalyst concentration of 4.0 × 10(-4) M in the mixed solvent system of CH3CN-H2O (3 : 1, v/v). In addition, the mechanism of H2 generation in the photolysis system was briefly discussed.

An investigation for public acceptance of laparoendoscopic single-site surgery.

UNLABELLED: Objective : Laparoendoscopic single-site surgery (LESS) is the latest innovation in minimally invasive surgery with unconfirmed advantages. The public perception of LESS is the basis of carrying out the surgery. METHODOLOGY: Participants from the outpatient department were invited to rate, on a 5-point Likert scale, the important factors including scar, complications, cost, pain and hospital stay in choosing surgery. In addition, those who preferred LESS would continue to make their choices as the risks of LESS in above mentioned aspects rose. RESULTS: About 85% of the questionnaires were included in the analysis. Complication was the most important factor with an average score of 4.77±0.43, followed by pain (3.84±0.96), scar (3.57±1.17), cost (3.41±0.87) and hospital stay (3.04±0.86). Of the 196 participants, 132 (67%) preferred LESS with younger age (35.3±10.64 versus 40.4 ±9.6, P=0.001). Better cosmesis was the only factor that made the participants choose LESS (3.78±1.11 versus 3.13±1.19, P<0.005). Almost 90% of the participants could accept the hypothesis (incision length of 3.5cm, cost up to 120%, pain up to 120%, hospital stay of 5 days), while only 50% of participants could accept the risk of complications of 6%. CONCLUSIONS: Complication is the most important factor that the public are concerned about in choosing surgery. LESS is preferred by young who care more concerned about the cosmesis, even with moderately elevated risks of extending incision and increasing hospital cost, postoperative pain and hospital stay.

Plant-on-chip: Core morphogenesis processes in the tiny plant Wolffia australiana.

A plant can be thought of as a colony comprising numerous growth buds, each developing to its own rhythm. Such lack of synchrony impedes efforts to describe core principles of plant morphogenesis, dissect the underlying mechanisms, and identify regulators. Here, we use the minimalist known angiosperm to overcome this challenge and provide a model system for plant morphogenesis. We present a detailed morphological description of the monocot Wolffia australiana, as well as high-quality genome information. Further, we developed the plant-on-chip culture system and demonstrate the application of advanced technologies such as single-nucleus RNA-sequencing, protein structure prediction, and gene editing. We provide proof-of-concept examples that illustrate how W. australiana can decipher the core regulatory mechanisms of plant morphogenesis.

Two new CdII and ZnII coordination polymers incorporating 1-aminobenzene-3,4,5-tricarboxylic acid: synthesis, crystal structure and characterization.

Aminobenzoic acid derivatives are widely used in the preparation of new coordination polymers since they contain O-atom donors, as well as N-atom donors, and have a rich variety of coordination modes which can lead to polymers with intriguing structures and interesting properties. Two new coordination polymers incorporating 1-aminobenzene-3,4,5-tricarboxylic acid (H3abtc), namely, poly[(µ3-1-amino-5-carboxybenzene-3,4-dicarboxylato)diaquacadmium(II)], [Cd(C9H5NO6)(H2O)2]n, (I), and poly[[bis(µ5-1-aminobenzene-3,4,5-tricarboxylato)triaquatrizinc(II)] dihydrate], {[Zn3(C9H4NO6)2(H2O)3]·2H2O}n, (II), have been prepared and structurally characterized by single-crystal X-ray diffraction. In polymer (I), each tridentate 1-amino-5-carboxybenzene-3,4-dicarboxylate (Habtc2-) ligand coordinates to three CdII ions to form a two-dimensional network structure, in which all of the CdII ions and Habtc2- ligands are equivalent, respectively. Polymer (II) also exhibits a two-dimensional network structure, in which three crystallographically independent ZnII ions are bridged by two crystallographically independent pentadentate 1-aminobenzene-3,4,5-tricarboxylate (abtc3-) ligands. This indicates that changing the metal ion can influence the coordination mode of the H3abtc-derived ligand and further influence the detailed architecture of the polymer. Moreover, the IR spectra, thermogravimetric analyses and fluorescence properties were investigated.

Effect of pH on the construction of CdII coordination polymers involving the 1,1'-[1,4-phenylenebis(methylene)]bis(3,5-dicarboxylatopyridinium) ligand.

Changing the pH value of a reaction system can result in polymers with very different compositions and architectures. Two new coordination polymers based on 1,1'-[1,4-phenylenebis(methylene)]bis(3,5-dicarboxylatopyridinium) (L2-), namely catena-poly[[[tetraaquacadmium(II)]-µ2-1,1'-[1,4-phenylenebis(methylene)]bis(3,5-dicarboxylatopyridinium)] 1.66-hydrate], {[Cd(C22H14N2O8)(H2O)4]·1.66H2O}n, (I), and poly[{µ6-1,1'-[1,4-phenylenebis(methylene)]bis(3,5-dicarboxylatopyridinium)}cadmium(II)], [Cd(C22H14N2O8)]n, (II), have been prepared in the presence of NaOH or HNO3 and structurally characterized by single-crystal X-ray diffraction. In polymer (I), each CdII ion is coordinated by two halves of independent L2- ligands, forming a one-dimensional chain structure. In the crystal, these chains are further connected through O-H...O hydrogen bonds, leading to a three-dimensional hydrogen-bonded network. In polymer (II), each hexadentate L2- ligand coordinates to six CdII ions, resulting in a three-dimensional network structure, in which all of the CdII ions and L2- ligands are equivalent, respectively. The IR spectra, thermogravimetric analyses and fluorescence properties of both reported compounds were investigated.

Triptolide inhibits migration and proliferation of fibroblasts from ileocolonic anastomosis of patients with Crohn's disease via regulating the miR­16­1/HSP70 pathway.

Anastomotic fibrosis is highly likely to lead to reoperation in Crohn's disease (CD) patients. Triptolide (TPL) is considered to have anti­inflammatory and antifibrotic effects in a variety of autoimmune diseases, including CD. The present study aimed to investigate the effects of TPL on fibroblasts from strictured ileocolonic anastomosis of patients with CD and its underlying mechanism. Primary fibroblasts were obtained from strictured anastomosis tissue (SAT) samples and matched anastomosis­adjacent normal tissue (NT) samples which were collected from 10 CD patients who underwent reoperation because of anastomotic stricture. Reverse transcription­quantitative polymerase chain reaction (RT­qPCR) was used to measure miR­16­1 and heat shock protein 70 (HSP70) levels. Western blotting was conducted to determine expression of HSP70, collagen I (Col­I), collagen III (Col­III) and α­smooth muscle actin (α­SMA) proteins. Agomir­16­1 and antagomir­16­1 were used to up and downregulate the expression of miR­16­1, respectively. Small interfering RNA (siRNA) was employed to inhibit the expression of HSP70. A wound healing assay was performed to measure the migration of fibroblasts. Cell proliferation was evaluated by MTT and 5­bromo­2­deoxyrudidine assays. Cell apoptosis was determined by caspase­3 activity and TUNEL assays. The results demonstrated that the levels of Col­I, Col­III and α­SMA were all significantly upregulated in SAT compared with NT. miR­16­1 levels in the SAT group were significantly compared with the NT group; conversely, the expression levels of HSP70 mRNA and protein in the SAT group were significantly lower compared with the NT group. Next, fibroblasts were treated with TPL to examine its effect on the miR­16­1/HSP70 pathway. The results demonstrated that the elevated expression of miR­16­1 in the SAT group was effectively inhibited by TPL treatment. Compared with the NT group, both the mRNA and protein levels of HSP70 were significantly downregulated in the SAT group cells, while TPL exhibited a strong promoting effect on HSP70 synthesis. Furthermore, upregulation of miR­16­1 reversed the effect of TPL on the miR­16­1/HSP70 pathway in fibroblasts from SAT. Overexpression of miR­16­1 significantly reversed the inhibitory effects of TPL treatment on migration, proliferation and extracellular matrix (ECM)­associated protein expression of fibroblasts from SAT. Finally, downregulation of miR­16­1 caused similar effects to the fibroblasts as the TPL treatment; however, the inhibitory effects on cell biological functions induced by antagomir­16­1 were all significantly reversed by HSP70 silencing. The present findings indicated that TPL may be a potential therapeutic option for postoperative anastomosis fibrosis of patients with CD. The miR­16­1/HSP70 pathway had a substantial role in the inhibitory effects of TPL on migration, proliferation and ECM synthesis rate of fibroblasts from strictured anastomosis tissues.

Laparoscopic hepatectomy for the treatment of Caroli's disease: a case report.

Caroli disease is a rare congenital disorder characterized by nonobstructive dilatation of intrahepatic ducts. In cases with symptomatic intrahepatic manifestations, treatment should correspond to the type with hepatic resection for localized disease and transplantation for diffuse forms. If possible, complete resection of the cysts can cure the symptoms and avoid the risk of malignancy. A 66-year-old woman presented to Wuxi Xishan People's Hospital with recurrent intermittent upper quadrant abdominal pain. Further examinations suggested the diagnosis of Caroli disease limited to the left hepatic lobe. She underwent laparoscopic hepatectomy. Pathological examination confirmed the diagnosis of Caroli disease, and no malignancy was found. There were no immediate complications and no long-term complications after one and one-half years of follow-up. Laparoscopic hepatectomy could be a feasible, safe treatment option for localized Caroli disease.

Two N,N'-bis-(pyridin-4-yl)pyridine-2,6-dicarboxamide coordination compounds.

The molecular structures of tetra-aqua-[N,N'-bis-(pyridin-4-yl)pyridine-2,6-dicar-boxamide]-sulfatomanganese(II) dihydrate, [Mn(SO4)(C17H13N5O2)(H2O)4]·2H2O or [Mn(H2L1)(SO4)(H2O)4]·2H2O, (I), and tetra-aqua-bis[N,N'-bis-(pyridin-4-yl)pyridine-2,6-dicar-boxamide]cadmium(II) sulfate tetra-hydrate, [Cd(C17H13N5O2)2(H2O)4]SO4·4H2O or [Cd(H2O)4(H2L1)2]·SO4·4H2O, (II), both contain a central metal atom in a distorted octa-hedral geometry coordinated equatorially by four oxygen atoms from water mol-ecules. In (I), the axial positions are occupied by a nitro-gen atom from H2L1 and an oxygen atom from the sulfate anion, whereas in (II), the axial positions contain two nitro-gen atoms from two different H2L1 ligands and the sulfate anion acts as the charge-balancing ion. π-π stacking between pyridine rings and a network of hydrogen bonds involving the water molecules and the sulfate anions play a crucial role in the mol-ecular self-assembly of the two structures.

Catena-poly[[bis[5-(4-pyridyl-kappaN)-2-(2-pyridylmethylsulfanyl)-1,3,4-oxadiazole]cadmium(II)]-di-mu-thiocyanato-kappa2N:S;kappa2S:N].

The title compound, [Cd(NCS)(2)(C(13)H(10)N(4)OS)(2)](n), contains SCN(-) anions acting as end-to-end bridging ligands which utilize both S and N atoms to link cadmium(II) centers into one-dimensional double chains. The multidentate 5-(4-pyridyl)-2-(2-pyridylmethylsulfanyl)-1,3,4-oxadiazole ligands behave as monodentate terminal ligands, binding metal centers only through the N atoms of the 4-pyridyl groups. Two types of eight-membered rings are formed by two SCN(-) anions bridging Cd(II) centers, viz. planar and chair conformation, which are alternately disposed along the same chain. Finally, chains define a two-dimensional array through two different interchain pi-pi stacking interactions.

Triptolide exerts protective effects against fibrosis following ileocolonic anastomosis by mechanisms involving the miR-16-1/HSP70 pathway in IL-10-deficient mice.

Surgeries, particularly ileocecal resection (ICR), are often required in the treatment of Crohn's disease (CD). However, recurrences are common for patients who undergo ICR, and anastomotic fibrosis is the main cause of re-operation. The present study aimed to investigate the therapeutic effects of triptolide (TPL) in ameliorating fibrosis following ileocolonic anastomosis. A model of IL­10­/­ mice undergoing ICR was used to study postsurgical inflammation and fibrosis of anastomosis. For this purpsose, interleukin (IL)­10­/­ mice were randomly divided into 3 groups as follows: the control group, the saline­treated group subjected to ICR (ST­ICR) and the TPL­treated group subjected to ICR (TT­ICR). Wild­type (WT) mice of matching ages were assigned to the WT group. The effects of TPL treatment on ileocolonic anastomosis were determined by histopathological evaluation, western blot analysis and ELISA. The analysis of the effects of TPL treatment on microRNA­16­1 (miR­16­1) and heat shock protein 70 (HSP70) expression was carried out by RT­qPCR and western blot analysis. Compared with the control group, significantly higher inflammation scores following anastomosis were observed in the ST­ICR group (P<0.05), although reversion was observed in the TT­ICR group, which was consistent with changes in the area of CD4+ cell infiltration. The elevated fibrosis scores and the overexpression of procollagen I and III in the ST­ICR group were all inhibited by TPL. With an increase in the severity of inflammation and fibrosis, the levels of IL­6, tumor necrosis factor­α (TNF­α) and transforming growth factor­ß1 (TGF­ß1) increased; however, a significant decrease in these levels was observed following treatment with TPL (P<0.05). The results of RT­qPCR revealed that the upregulated miR­16­1 levels in the ST­ICR group were significantly reduced by TPL. HSP70, which can be inhibited by miR-16-1, ameliorates anastomotic inflammation and fibrosis. Thus, the present study demonstrates that TPL exerts a protective effect against fibrosis following anastomosis in CD. The miR­16­1/HSP70 signaling pathway, which can be regulated by TPL, may thus represent a novel therapeutic option in CD that deserves further investigation.

Efficient conversion of wheat straw wastes into biohydrogen gas by cow dung compost.

Efficient conversion of wheat straw wastes into biohydrogen gas by cow dung compost was reported for the first time. Batch tests were carried out to analyze influences of several environmental factors on biohydrogen production from wheat straw wastes. The performance of biohydrogen production using the raw wheat straw and HCl pretreated wheat straw was then compared in batch fermentation tests. The maximum cumulative hydrogen yield of 68.1 ml H2/g TVS was observed at 126.5 h, the value is about 136-fold as compared with that of raw wheat straw wastes. The maximum hydrogen production rate of 10.14 ml H2/g TVS h was obtained by a modified Gompertz equation. The hydrogen content in the biogas was 52.0% and there was no significant methane observed in this study. In addition, biodegradation characteristics of the substrate were also discussed. The experimental results showed that the pretreatment of the substrate plays a key role in the conversion of the wheat straw wastes into biohydrogen by the composts generating hydrogen.

Expression levels of IL-17 and TNF-α in degenerated lumbar intervertebral discs and their correlation.

The present study aimed to investigate the expression and roles of interleukin (IL)-17 and tumor necrosis factor (TNF)-α in intervertebral disc degeneration (IDD) and to identify the association between the effects of IL-17 and TNF-α in IDD. This may increase understanding of the pathogenic mechanism underlying IDD, and aid the development of alternative therapies. The experimental group consisted of 40 samples of nucleus pulposus tissue obtained from the intervertebral discs (IVDs) of patients with IDD by surgical intervention, and was further divided into an annulus fibrosus disrupted group, comprising 18 patients in which the external annulus was ruptured, and an annulus fibrosus intact group comprising 22 patients. The control group consisted of 20 samples of nucleus pulposus tissue from the IVDs of patients with traumatic lumbar disc fractures. The mRNA and protein expression levels of IL-17 and TNF-α in the 50 tissue samples were detected by semi-quantitative reverse transcription polymerase chain reaction and immunohistochemical staining, respectively, and the results were statistically analyzed. The IL-17 and TNF-α protein and mRNA expression levels in the annulus fibrosus disrupted and annulus fibrosus intact groups were both higher compared with those in the control group. In addition, the expression levels of IL-17 and TNF-α in the annulus fibrosus disrupted group were significantly higher compared with those in the annulus fibrosus intact group (P<0.01). A positive correlation was identified between the mRNA and protein expression levels of IL-17 and TNF-α in the experimental group (r=0.957, P<0.01). IL-17 and TNF-α may therefore be involved in the progression of human IDD, and may have synergistic effects in the development of IDD.

Simultaneous determination of polycyclic aromatic hydrocarbons and tobacco-specific N-nitrosamines in mainstream cigarette smoke using in-pipette-tip solid-phase extraction and on-line gel permeation chromatography-gas chromatography-tandem mass spectrometry.

In this study, a silica/primary secondary amine (SiO2/PSA) was used as an in-pipette-tip solid phase extraction (SPE) sorbent for the simultaneous determination of polycyclic aromatic hydrocarbons (PAHs) and tobacco-specific N-nitrosamines (TSNAs) in mainstream cigarette smoke (MSS). We investigated several parameters including an extraction procedure of total particulate matter, type and amount of sorbent and on-line gel permeation chromatography parameters to obtain optimum conditions for a new strategy to target analytes. Under the optimized conditions, we developed a method for the simultaneous determination of PAHs and TSNAs in MSS by coupling in-pipette-tip SPE procedures to an on-line gel permeation chromatography-gas chromatography-tandem mass spectrometry (on-line GPC-GC-MS(2)). Our method had limits of detection for target analytes ranging from 0.01 to 0.23ng/cig. Good linearities were obtained with coefficients of determination (R(2)) greater than 0.9984 for all target analytes. Good reproducibility was obtained as intra- and inter-day precisions, and the relative standard deviations were less than 11.4 and 13.3%, respectively. The recoveries were in the range of 77.1-108.6% at different concentrations for real samples. Compared to previous standard methods for the determination of PAHs and TSNAs in MSS, our method was highly effective, fast, and had low consumption of organic solvent and a high degree of automation. Finally, our method successfully analyzed PAHs and TSNAs in real samples, and no significant deviations were observed when compared to similar analysis using standard methods.

Direct degradation of cellulosic biomass to bio-hydrogen from a newly isolated strain Clostridium sartagoforme FZ11.

A mesophilic hydrogen-producing strain, Clostridium sartagoforme FZ11, had been newly isolated from cow dung compost acclimated using microcrystalline cellulose (MCC) for at least 30 rounds in an anaerobic bioreactor, and identified by the 16S rDNA gene sequencing, which could directly utilized various carbon sources, especially cellulosic biomass, to produce hydrogen. The maximum hydrogen yields from MCC (10 g/l) and carboxymethyl cellulose (CMC, 10 g/l) were 77.2 and 64.6 ml/g, separately. Furthermore, some key parameters of affecting hydrogen production from raw corn stalk were also optimized. The maximal hydrogen yield and substrate degradation rate from raw corn stalk were 87.2 ml/g and 41.2% under the optimized conditions with substrate concentration of 15 g/l, phosphate buffer of 0.15 M, urea of 6 g/l and initial pH of 6.47 at 35 °C. The result showed that the strain FZ11 would be an ideal candidate to directly convert cellulosic biomass into bio-hydrogen without substrate pretreatment.

Effective conversion of maize straw wastes into bio-hydrogen by two-stage process integrating H2 fermentation and MECs.

The enhanced H2 production from maize straw had been achieved through the two-stage process of integrating H2 fermentation and microbial electrolysis cells (MECs) in the present work. Several key parameters affecting hydrolysis of maize straw through subcritical H2O were optimized by orthogonal design for saccharification of maize straw followed by H2 production through H2 fermentation. The maximum reducing sugar (RS) content of maize straw reached 469.7 mg/g-TS under the optimal hydrolysis condition with subcritical H2O combining with dilute HCl of 0.3% at 230 °C. The maximum H2 yield, H2 production rate, and H2 content was 115.1 mL/g-TVS, 2.6 mL/g-TVS/h, and 48.9% by H2 fermentation, respectively. In addition, the effluent from H2 fermentation was used as feedstock of MECs for additional H2 production. The maximum H2 yield of 1060 mL/g-COD appeared at an applied voltage of 0.8 V, and total COD removal reached about 35%. The overall H2 yield from maize straw reached 318.5 mL/g-TVS through two-stage processes. The structural characterization of maize straw was also carefully investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) spectra.