Bioelectricity and CO2-to-butyrate production using photobioelectrochemical cells with bio-hydrogel.

Bio-photoelectrochemical cell (BPEC) is an emerging technology that can convert the solar energy into electricity or chemicals. However, traditional BPEC depending on abiotic electrodes is challenging for microbial/enzymatic catalysis because of the inefficient electron exchange. Here, electroactive bacteria (Shewanella loihica PV-4) were used to reduce graphene oxide (rGO) nanosheets and produce co-assembled rGO/Shewanella biohydrogel as a basic electrode. By adsorbing chlorophyll contained thylakoid membrane, this biohydrogel was fabricated as a photoanode that delivered maximum photocurrent 126 µA/cm3 under visible light. Impressively, the biohydrogel could be served as a cathode in BPEC by forming coculture system with genetically edited Clostridium ljungdahlii. Under illumination, the BPEC with above photoanode and cathode yielded âˆ¼ 5.4 mM butyrate from CO2 reduction, 169 % increase compared to dark process. This work provided a new strategy (nanotechnology combined with synthetic biology) to achieve efficient bioelectricity and valuable chemical production in PBEC.

Artificial and Biosynthetic Nanoparticles Boost Bioelectrochemical Reactions via Efficient Bidirectional Electron Transfer of Shewanella loihica.

Bioelectrochemical reactions using whole-cell biocatalysts are promising carbon-neutral approaches because of their easy operation, low cost, and sustainability. Bidirectional (outward or inward) electron transfer via exoelectrogens plays the main role in driving bioelectrochemical reactions. However, the low electron transfer efficiency seriously inhibits bioelectrochemical reaction kinetics. Here, a three dimensional and artificial nanoparticles-constituent inverse opal-indium tin oxide (IO-ITO) electrode is fabricated and employed to connect with exoelectrogens (Shewanella loihica PV-4). The above electrode collected 128-fold higher cell density and exhibited a maximum current output approaching 1.5 mA cm-2 within 24 h at anode mode. By changing the IO-ITO electrode to cathode mode, the exoelectrogens exhibited the attractive ability of extracellular electron uptake to reduce fumarate and 16 times higher reverse current than the commercial carbon electrode. Notably, Fe-containing oxide nanoparticles are biologically synthesized at both sides of the outer cell membrane and probably contributed to direct electron transfer with the transmembrane c-type cytochromes. Owing to the efficient electron exchange via artificial and biosynthetic nanoparticles, bioelectrochemical CO2 reduction is also realized at the cathode. This work not only explored the possibility of augmenting bidirectional electron transfer but also provided a new strategy to boost bioelectrochemical reactions by introducing biohybrid nanoparticles.

[Size distribution characteristics of particulate mercury on haze and non-haze days].

With the rapid economic development, China suffers from the severe haze and atmospheric mercury pollution. Particulate mercury transport has an important significance in its global cycle. In order to investigate the distribution characteristics of particulate mercury, 12 degrees Nano-moudi (6.2-9.9 µm, 3.1-6.2 µm, 1.8-3.1 µm, 1.0-1.8 µm, 0.56-1.0 µm, 0.32-0.56 µm, 0.18- 0.32 µm, 0.10-0.18 µm, 0.056-0.10 µm, 0.032-0.056 µm, 0.018-0.032 µm, 0.010-0.018 µm) impactor was used to measure the size distributions of atmospheric particulate mercury on both haze and non-haze days in Shanghai. The results indicated that particulate mercury levels were positively correlated with those of the particles. The average concentration of particulate mercury (0.31 ng x m (-3)) on haze days was 2-3 times than that on non-haze days (0.11 ng x m(-3)). The mass size distributions of aerosols and particulate mercury showed bimodal distributions. The peak shifted from 0.56-1.0 µm and 3.1-6.2 µm on haze days to 0.32-0.56 µm and 3.1-6.2 µm on non-haze days. The particles with aerodynamic diameter smaller than 1 µm which could stay for a long time and transport for a long distance, had higher particulate mercury concentrations. The average contribution of particulate mercury to total PM aerosol were higher on haze days (0.029 ng x µg(-1)) than on non-haze days (0.015 ng x µg(-1)), indicating that secondary particles typically grew faster than mercury during the haze pollution events. The particulate mercury concentration in accumulation mode was 2.06 ng x m(-3) on haze days, while it was 0.55 ng x m(-3) on non-haze days. The large increase of the accumulation mode particles was a main reason for the formation of haze. Emissions from the coal burning as well as road surface dust and dust from long-range transport accounted for the serious pollution on haze days.

Complete mitochondrial genome of a new subspecies of the blue sheep, Pseudois nayaur (Cetartiodactyla: Caprinae) from Helan Mountain in China.

The population of blue sheep, Pseudois nayaur, from Helan Mountain in China is considered as a new subspecies. We first determined and annotated its complete mitochondrial genome. The mitogenome is 16,795 bp in length, consisting of 13 protein-coding genes, 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes and a control region. As in other mammals, most mitochondrial genes are encoded on the heavy strand, except for ND6 and eight tRNA genes, which are encoded on the light strand. Its overall base composition is A: 33.2%, T: 26.6%, C: 26.8% and G: 13.3%. The complete mitogenome of the new subspecies of P. nayaur could provide an important data to further explore the taxonomic status of the subspecies.

Optimization of hollow waveguides as absorption cells for spectroscopic gas sensing.

Flexible and low-loss hollow waveguide has many advantages as an absorption cell for spectroscopic gas sensing. The characteristics of the sensing system are dependent on the parameters of the hollow waveguide cell. In this paper, a mathematical model was proposed to analyze the waveguide cell by considering waveguide loss, effective optical path length, and signal-to-noise ratio of the system. Simulation results show that the gas absorption intensity and system sensitivity are dependent not only on the waveguide length but also on the bore-diameter, signal-to-noise ratio, and the concentration of the target gases. The results provide optimizing methods for the sensing system and algorithms for error compensation. Preliminary experiments on concentration detection of methane gas were carried out and measured data showed good agreements with the simulation results.

[Nocturnal heart rhythm disorder in patients with obstructive sleep apnea syndrome].

OBJECTIVE: To explore the clinical characteristics of patients with obstructive sleep apnea syndrome (OSAS) and nocturnal arrhythmia. METHODS: During September 2010 to August 2011, a total of 446 subjects were recruited from Department of Sleep Breathing Disorder, Third Hospital, Hebei Medical University to receive polysomnography examination and electrocardiogram monitoring. According to the results, they were classified as mild (5 ≤ AHI < 15/h) or moderate (15 ≤ AHI < 40/h) or severe (AHI ≥ 40/h) OSAS. Then the incidence of different types of arrhythmias, risk factors and the relationship with OSAS severity were examined. RESULTS: Among 446 patients, the incidence of arrhythmia was 24.4% (109/446). The severity of OSAS (r = 1.857, P = 0.043) and age (r = 1.030, P = 0.003) had a positive relationship with the incidence of arrhythmias.Sinus bradycardia (79.8%, 87/109) and accidental ventricular premature beat (54.1%, 59/109) were most likely to occur than other types of arrhythmias (P < 0.01).In moderate and severity OSAS patients, the incidence of sinus bradycardia, frequent atrial premature beat, combined over two kinds of arrhythmias, atrial fibrillation and atrioventricular block were 50.0%, 0, 42.9%, 7.1%,0 and 90.9%, 14.8%, 57.9%, 4.5%, 5.7% respectively. And they were significantly higher than those of mild patients (all = 0) (all P < 0.05). CONCLUSIONS: Age and severity of OSAS have a positive relationship with the incidence of nocturnal arrhythmias.Sinus bradycardia and ventricular premature beat are the most likely to occur in OSAS patients.In moderate and severe group, sinus bradycardia, frequent atrial premature beat, combined over two kinds of arrhythmias, atrial fibrillation and atrioventricular block are more commonly encountered.

[Effect of the combination of bushen xuguan recipe and ruanjian huayu recipe on the MMP-2 expression in endometriosis rats].

OBJECTIVE: To observe the effect of the combination of Bushen Xuguan Recipe (BXR) and Ruan-jian Huayu Recipe (RHR) on the matrix metalloproteinases-2 (MMP-2) expression of rats with endometriosis (EMS), and to study the pathogenesis and mechanism of EMS. METHODS: The EMS rat model was established. Successfully modeled female SD rats were randomly divided into the combination group (BXR+RHR), the RHR group, and the model group. And a normal control group was set up. After 4 weeks of medicinal treatment, rats were sacrificed in the oestrus cycle. MMP-2 distribution and the staining density in ectopic and eutopic endometrium of the rats were observed under microscope. The MMP-2 expression was determined by immunohistochemical assay (SP method). RESULTS: The MMP-2 expression in the ectopic endometrial tissues of rats in the model group were significantly higher than that of the normal control group (P<0.01). Compared with the model group, the MMP-2 expression decreased in the combination group and the RHR group (P<0.05). The therapeutic effect of the combination group was most obvious by observing the distribution of MMP-2 and changes of positive staining. CONCLUSIONS: The occurrence of EMS was correlated with increased activities of MMP-2. The combination method could inhibit the activities of MMP-2 in the ectopic endometrial tissues of EMS rats more effectively than RHR alone, which might be achieved through improving the endocrine environment, and reducing the "invasion" capability of the ectopic endometrium.