A reactor system combining reductive dechlorination with co-metabolic oxidation for complete degradation of tetrachloro-entylene

A laboratory sequential anaerobic aerobic bioreactor system, which consisted of an anaerobic fixed film reactor and two aerobic chemostats, was set up to degrade tetrachloroethylene (PCE) without accumulating highly toxic degradation intermediates. A soil enrichment culture, which could reductively dechlorinate 900 μM (ca. 150 mg/L) of PCE stoichiometrically into cis 1,2 dichloroethylene ( cis DCE), was attached to ceramic media in the anaerobic fixed film reactor. A phenol degrading strain, Alcaligenes sp. R5, which can efficiently degrade cis DCE by co metabolic oxidation, was used as inoculum for the aerobic chemostats consisted of a transformation reactor and a growth reactor. The anaerobic fixed film bioreactor showed more than 99 % of PCE transformation into cis DCE in the range of influent PCE concentration from 5 μM to 35 μM at hydraulic retention time of 48h. On the other hand, efficient degradation of the resultant cis DCE by strain R5 in the following aerobic system could not be achieved due to oxygen limitation. However, 54% of the maximum cis DCE degradation was obtained when 10 μmol of hydrogen peroxide (H 2O 2) was supplemented to the transformation reactor as an additional oxygen source. Further studies are needed to achieve more efficient co metabolic degradation of cis DCE in the aerobic reactor.

Dopant-Tunable Ultrathin Transparent Conductive Oxides for Efficient Energy Conversion Devices

Ultrathin film-based transparent conductive oxides(TCOs)with a broad work function(WF)tunability are highly demanded for e cient energy conversion devices.However,reducing the film thickness below 50 nm is limited due to rapidly increasing resistance;furthermore,introducing dopants into TCOs such as indium tin oxide(ITO)to reduce the resistance decreases the transparency due to a trade-o between the two quantities.Herein,we demonstrate dopant-tunable ultrathin(≤50 nm)TCOs fabricated via electric field-driven metal implantation(m-TCOs;m=Ni,Ag,and Cu)without com-promising their innate electrical and optical properties.The m-TCOs exhibit a broad WF variation(0.97 eV),high transmittance in the UV to visible range(89–93%at 365 nm),and low sheet resistance(30–60Ωcm-2).Experimental and theoretical analyses show that interstitial metal atoms mainly a ect the change in the WF without substantial losses in optical transparency.The m-ITOs are employed as anode or cathode electrodes for organic light-emitting diodes(LEDs),inorganic UV LEDs,and organic photovoltaics for their universal use,leading to outstanding performances,even without hole injection layer for OLED through the WF-tailored Ni-ITO.These results verify the proposed m-TCOs enable e ective carrier transport and light extraction beyond the limits of traditional TCOs.

Melatonin ameliorates tau-related pathology via the miR-504-3p and CDK5 axis in Alzheimer’s disease

Background:Intracellular accumulation of the microtubule-associated protein tau and its hyperphosphorylated forms is a key neuropathological feature of Alzheimer’s disease(AD).Melatonin has been shown to prevent tau hyperphosphorylation in cellular and animal models.However,the molecular mechanisms by which melatonin attenuates tau hyperphosphorylation and tau-related pathologies are not fully understood.Methods:Immunofluorescence,immunoblotting analysis and thioflavin-S staining were employed to examine the effects of early and late treatment of melatonin on tau-related pathology in hTau mice,in which nonmutated human tau is overexpressed on a mouse tau knockout background.High-throughput microRNA(miRNA)sequencing,quantitative RT-PCR,luciferase reporter assay and immunoblotting analysis were performed to determine the molecular mechanism.Results:We found that both early and late treatment of melatonin efficiently decreased the phosphorylation of soluble and insoluble tau at sites related to AD.Moreover,melatonin significantly reduced the number of neurofibrillary tangles(NFTs)and attenuated neuronal loss in the cortex and hippocampus.Furthermore,using miRNA microarray analysis,we found that miR-504-3p expression was upregulated by melatonin in the hTau mice.The administration of miR-504-3p mimics dramatically decreased tau phosphorylation by targeting p39,an activator of the well-known tau kinase cyclin-dependent kinase 5(CDK5).Compared with miR-504-3p mimics alone,co-treatment with miR-504-3p mimics and p39 failed to reduce tau hyperphosphorylation.Conclusions:Our results suggest for the first time that melatonin alleviates tau-related pathologies through upregulation of miR-504-3p expression by targeting the p39/CDK5 axis and provide novel insights into AD treatment strategies.

Electrochemically metal-doped reduced graphene oxide films:Properties and applications

The fine control of doping levels in graphene materials such as reduced graphene oxide(RGO)is important to properly manipulate their ambipolar transport characteristics for various device applications.However,conventional doping methods involve complex chemical reactions,large-scale doping processes,and poor stability.Herein,a simple and controllable electrochemical doping treatment(EDT),performed via the conductive channels created at the RGO surface by the application of an electric field,is introduced to tailor the electrical properties of RGO films.X-ray photoelectron spectroscopy and Raman spectroscopy measurements are performed to detect the presence of Ni atoms in RGO films after the EDT(EDT-RGO).Then,EDT-RGO field-effect transistors(FETs)are fabricated with different doping areas(0 to 100%fractional area)on the RGO active channel to investigate the effect and selective-area doping capability of the EDT.Owing to p-type doping compensation by the intercalated Ni atoms,the electron mobility of the EDT-RGO FET decreases from 1.40 to 0.12 cm2 V-1s-1 compared with that of the undoped RGO-FET,leading to the conversion from ambipolar to unipolar p-type transfer characteristics.