Polarity-Differentiated Dielectric Materials in Monolayer Graphene Charge-Regulated Field-Effect Transistors for an Artificial Reflex Arc and Pain-Modulation System of the Spinal Cord.

The nervous system is a vital part of organisms to survive and it endows them with remarkable abilities, such as perception, recognition, regulation, learning, and decision-making, by intertwining myriad neurons. To realize such outstanding efficacies and functions, many artificial devices and systems have been investigated to emulate the operating principles of the nervous system. Here, an artificial reflex arc (ARA) and artificial pain modulation system (APMS) are proposed to imitate the unconscious behaviors of the spinal cord. Gdx Oy - and Alx Oy -based charge-regulated field-effect transistors (CRFETs) with a monolayer graphene channel are fabricated and adopted as inhibitory and excitatory synapses, respectively, under the same pulse signals to mimic the biological reflex arc through a connection with a poly(vinylidene fluoride-co-trifluoroethylene)-based actuator. Additionally, a memristor is integrated with a CRFET as the interneuron to regulate the Dirac point by controlling the voltage drop on the graphene channel, analogous to the descending pain-inhibition system in the spinal cord, to prevent excessive pain perception. The proposed ARA and APMS provide a significant step forward to realizing the functions of the nervous system, giving promising potential for developing future intelligent alarm systems, neuroprosthetics, and neurorobotics.

Removal and simultaneous reduction of Cr(VI) by organo-Fe(III) composites produced during coprecipitation and coagulation processes.

Composites formed during the coprecipitation and/or coagulation of ubiquitous dissolved organic matter (DOM) and Fe in natural and waste water systems might be potential scavengers for Cr(VI) in terms of sorption and reduction. Our objective here was to determine sorption and simultaneous reduction of Cr(VI) on organo-Fe(III) composites (OFC) in relation coprecipitated pH and C/(C + Fe) ratios. Results showed the greatest Cr sorption of 51.8 mg g-1 on the OFC sample that was precipitated at pH 3 and contained the C/(C + Fe) molar ratio of 0.71. Wherein the Cr(VI) removal subsequent to the coprecipitation was dominated by the sorption on Fe hydroxides. Although amounts of total sorbed Cr decreased with increasing C/(C + Fe) molar ratio, the reverse trend on Cr(VI) reducibility compensated the Cr(VI) removal capability of OFC samples. With C/(C + Fe) molar ratios ≥ 0.89, the increasing amounts of coprecipitated organic matter that homogeneously distributed with Fe domains on OFC surfaces could trigger a significantly pronounced Cr reduction. Collectively, our results suggested an alternative method for Cr(VI) remediation by manipulating C/Fe ratios in suspensions. After the sorption of most Cr(VI) on Fe hydroxides, increasing C/Fe ratio in systems could further improve the Cr(VI) removal efficiency by the reduction of remaining Cr(VI) to Cr(III).

Use 3-D tomography to reveal structural modification of bentonite-enriched clay by nonionic surfactants: Application of organo-clay composites to detoxify aflatoxin B1 in chickens.

Although nonionic surfactants are relatively eco-friendly compared with cationic and anionic surfactants, few studies have investigated their application in modified clay. Herein we prepared organo-clay composites (OCCs) by mixing bentonite-enriched clay (BEC) with nonionic surfactants (Brij 30 and Igepal CO-890) and determined if these modifications would enable chickens to detoxify aflatoxin B1 (AFB1). For the first time, in situ three-dimensional (3-D) microstructures of modified BEC was characterized in suspension using transmission X-ray microscopy. Although X-ray diffraction patterns indicated the expansion in the spacing between planes of atoms (basal spacing) of surfactant-modified BEC, 3-D images indicated shrinkage in its microscale porous framework with increasing surfactant additions from 1 to 30 wt%. Such declining trends in porous dimensions caused by the dehydration in interlayer galleries of clays positively correlated with sorption amounts of AFB1 on OCCs. After chickens had consumed amended feeds for 11 weeks, AFB1 concentrations in liver, kidney, and plasma were significantly lower than in the control treatment. Thus, we suggest using BEC with 1 wt% surfactant addition, an amendment to chicken feeds, to detoxify AFB1. Modifying BEC with nonionic surfactants show the promise in mitigating AFB1 accumulation in chickens, which should improve food safety and reduce environmental contamination.

Phosphate Removal in Relation to Structural Development of Humic Acid-Iron Coprecipitates.

Precipitation of Fe-hydroxide (FH) critically influences the sequestration of PO4 and organic matter (OM). While coatings of pre-sorbed OM block FH surfaces and decrease the PO4 adsorption capacity, little is known about how OM/Fe coprecipitation influences the PO4 adsorption. We aimed to determine the PO4 adsorption behaviors on humic acid (HA)-Fe coprecipitates in relation to surface and structural characteristics as affected by HA types and C/(C + Fe) ratios using the Fe and P X-ray absorption spectroscopy. With increasing C/(C + Fe) ratios, the indiscernible changes in the proportion of near-surface C for coprecipitates containing HA enriched in polar functional groups implied a relatively homogeneous distribution between C and Fe domains. Wherein PO4 adsorbed on FH dominated the P inventory on coprecipitates, yielding PO4 sorption properties nearly equivalent to that of pure FH. Structural disruptions of FH caused by highly associations with polar functional groups of HA enhanced the C solubilisation. While polar functional groups were limited, coprecipitates consisted of core FH with surface outgrowth of HA. Although surface-attached HA that was vulnerable to solubilisation provided alternatively sites for PO4 via ternary complex formation with Fe bridges, it also blocked FH surfaces, leading to a decrease in PO4 adsorption.

Interface Modification of Bernal- and Rhombohedral-Stacked Trilayer-Graphene/Metal Electrode on Resistive Switching of Silver Electrochemical Metallization Cells.

Bernal- and rhombohedral-stacked trilayer graphene (B- and r-TLG) on nickel (Ni) and iridium (Ir) films acting as bottom electrodes (BEs) of silver electrochemical metallization cells (Ag-EMCs) have been investigated in this study. Prior to the fabrication of the EMC devices, Raman mapping and atomic force microscopy are applied to identify the B- and r-TLG sheets, with the latter revealing a significant D peak and a rough surface for the Ir film. The Ag-EMCs with the stacked BE of r-TLG on the Ir film show a conductive mechanism of Schottky emission at the positive top electrode bias for both high- and low-resistance states that can be examined by the resistance change with the device area and are modulated by pulse bias operation. Thus, an effective electron barrier height of 0.262 eV at the r-TLG and Ir interface is obtained because of the conspicuous energy gap of r-TLG on the Ir film and the van der Waals (vdW) gap between the r-TLG and Ir contact metal. With the use of Ni instead of Ir contact metal, the Ag-EMCs with TLG BE demonstrate +0.3 V/-0.75 V operation voltages, more than 104 s data retention at 115 °C and 250 times endurance testing, making the TLG sheets suitable for low-power nonvolatile memory applications on flexible substrates.

Stabilization of Natural Organic Matter by Short-Range-Order Iron Hydroxides.

Dissolved organic matter (DOM) is capable of modifying the surfaces of soil minerals (e.g., Fe hydroxides) or even forming stable co-precipitates with Fe(III) in a neutral environment. The DOM/Fe co-precipitation may alter biogeochemical carbon cycling in soils if the relatively mobile DOM is sorbed by soil minerals against leaching, runoff, and biodegradation. In this study, we aimed to determine the structural development of DOM/Fe co-precipitates in relation to changes in pH and C/(C + Fe) ratios using XRD, XPS, Fe K-edge XAS, FTIR, and C-NEXAFS techniques. The results showed that in the system with bulk C/(C + Fe) molar ratios ≤0.65, the ferrihydrite-like Fe domains were precipitated as the core and covered by the C shells. When the C/(C + Fe) molar ratio ranged between 0.71 and 0.89, the emerging Fe-C bonding suggested a more substantial association between Fe domains including edge- and corner-sharing FeO6 octahedra and DOM. With C/(C + Fe) bulk molar ratios ≥0.92, only corner-sharing FeO6 octahedra along with Fe-C bonding were found. The homogeneously distributed C and Fe domains caused the enhancement of Fe and C solubilization from co-precipitates. The C/(C + Fe) ratios dominated structural compositions and stabilities of C/Fe co-precipitates and may directly affect the Fe and C cycles in soils.

Accumulation of heavy metals and trace elements in fluvial sediments received effluents from traditional and semiconductor industries.

Metal accumulation in sediments threatens adjacent ecosystems due to the potential of metal mobilization and the subsequent uptake into food webs. Here, contents of heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) and trace elements (Ga, In, Mo, and Se) were determined for river waters and bed sediments that received sewage discharged from traditional and semiconductor industries. We used principal component analysis (PCA) to determine the metal distribution in relation to environmental factors such as pH, EC, and organic matter (OM) contents in the river basin. While water PCA categorized discharged metals into three groups that implied potential origins of contamination, sediment PCA only indicated a correlation between metal accumulation and OM contents. Such discrepancy in metal distribution between river water and bed sediment highlighted the significance of physical-chemical properties of sediment, especially OM, in metal retention. Moreover, we used Se XANES as an example to test the species transformation during metal transportation from effluent outlets to bed sediments and found a portion of Se inventory shifted from less soluble elemental Se to the high soluble and toxic selenite and selenate. The consideration of environmental factors is required to develop pollution managements and assess environmental risks for bed sediments.

Membrane protein assembly: two cytoplasmic phosphorylated serine sites of Vpu from HIV-1 affect oligomerization.

Viral protein U (Vpu) encoded by human immunodeficiency virus type 1 (HIV-1) is a short integral membrane protein which is known to self-assemble within the lipid membrane and associate with host factors during the HIV-1 infectivity cycle. In this study, full-length Vpu (M group) from clone NL4-3 was over-expressed in human cells and purified in an oligomeric state. Various single and double mutations were constructed on its phosphorylation sites to mimic different degrees of phosphorylation. Size exclusion chromatography of wild-type Vpu and mutants indicated that the smallest assembly unit of Vpu was a dimer and over time Vpu formed higher oligomers. The rate of oligomerization increased when (i) the degree of phosphorylation at serines 52 and 56 was decreased and (ii) when the ionic strength was increased indicating that the cytoplasmic domain of Vpu affects oligomerization. Coarse-grained molecular dynamic simulations with models of wild-type and mutant Vpu in a hydrated lipid bilayer supported the experimental data in demonstrating that, in addition to a previously known role in downregulation of host factors, the phosphorylation sites of Vpu also modulate oligomerization.

MS title: Catalytic oxidation and removal of arsenite in the presence of Fe ions and zero-valent Al metals.

Arsenic immobilization in acid mine drainage (AMD) is required prior to its discharge to safeguard aquatic organisms. Zero-valent aluminum (ZVAl) such as aluminum beverage cans (AlBC) was used to induce the oxidation of As(III) to As(V) and enhance the subsequent As removal from an artificially prepared AMD. While indiscernible As(III) oxidation was found in aerated ZVAl systems, the addition of 0.10-0.55mM Fe(II) or Fe(III) into the AMD significantly promoted the As(V) production. Reactions between Fe(II) and H2O2, which was produced through an oxidative reaction of ZVAl with dissolved oxygen, generated OH radicals. Such OH radicals subsequently induced the As(III) oxidation. Over the course of the Fenton like reaction, ZVAl not only directly generated the H2O2, but indirectly enhanced the OH radical production by replenishing Fe(II). Arsenite oxidation in the aerated ZVAl/Fe and AlBC/Fe systems followed zero- and first-order kinetics. Differences in the kinetic reactions of ZVAl and AlBC with respect to As(III) oxidation were attributed to higher productive efficiency of the oxidant in the AlBC systems. After the completion of As(III) oxidation, As(V) could be removed simultaneously with Al(III) and Fe(III) by increasing solution's pH to 6 to produce Al/Fe hydroxides as As(V) scavengers or to form Al/Fe/As co-precipitates.

Increased Cumulative Incidence of Dermatomyositis in Ulcerative Colitis: a Nationwide Cohort Study.

On a molecular level, two autoimmune diseases: ulcerative colitis (UC) and dermatomyositis share common genetic determinants. On a clinical level, case reports evidenced the co-occurrence of these two diseases. We therefore hypothesize that UC is potentially associated with increased cumulative incidence of dermatomyositis. The goals of this retrospective cohort study were to evaluate whether UC is associated with increased cumulative incidence of dermatomyositis independent of sex and age. For comparison, we also assessed the cumulative incidence of polymyositis in UC and control subjects. The study enrolled 3,133 UC subjects and 14,726 control subjects. The cumulative incidence of dermatomyositis was significantly higher in UC than that of control subjects (p = 0.026), but the cumulative incidence of polymyositis was comparable between UC and control subjects (p = 0.596). UC was independently associated with the increased incident dermatomyositis (hazard ratio: 6.19, 95% confidence interval = 1.77-21.59, p = 0.004) after adjusting for sex, age, and concomitant rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis. Similar trends of increased dermatomyositis in UC were observed when patients were stratified based on sex and age. In conclusion, our findings suggest that UC is probably associated with increased cumulative incidence of dermatomyositis, independent of sex, age, and concomitant autoimmune diseases.

Molecular Structures of Al/Si and Fe/Si Coprecipitates and the Implication for Selenite Removal.

Aluminum and iron oxides have been often used in the coagulation processes during water purification due to their unique surface properties toward anions. In the presence of silica, the coprecipitation of Al/Si or Fe/Si might decrease the efficiency of wastewater purification and reuse. In this study, surface properties and molecular structures of Al/Si and Fe/Si coprecipitates were characterized using spectroscopic techniques. Also, the selenite removal efficiency of Al/Si and Fe/Si coprecipitates in relation to their surface and structural properties was investigated. While dissolved silicate increased with increasing pH from Fe/Si coprecipitates, less than 7% of silicate was discernible from Al/Si samples over the range from acidic to alkaline conditions. Our spectroscopic results showed that the associations between Al and Si were relatively stronger than that between Fe and Si in coprecipitates. In Al/Si coprecipitates, core-shell structures were developed with AlO6/AlO4 domains as the shells and Si frameworks polymerized from the SiO2 as the cores. However, Si framework remained relatively unchanged upon coprecipitation with Fe hydroxides in Fe/Si samples. The Si core with Al shell structure of Al/Si coprecipitates shielded the negative charges from SiO2 and thereby resulted in a higher adsorption capacity of selenite than Fe/Si coprecipitates.

Allopurinol and the incidence of bladder cancer: a Taiwan national retrospective cohort study.

Our aim is to investigate the risk association between allopurinol use and cancer incidence among gout patients using clinical evidence. Newly diagnosed male patients with gout, 20 years or older, were included after excluding those who had a diagnosis of type 2 diabetes, and were followed up for 12 years in a retrospective cohort study of one million outpatients of a national database. The gout patients were matched to male controls by age and first diagnosis date of gout disease. We then estimated the risk associations between incident cancers and duration of allopurinol use by Cox hazard regression, age-adjusted standardized incidence ratio, and incidence per 1000 person-years. A total of 24 050 gout patients and 76 129 controls were included. The incidence of all-cause cancers for gout patients and controls was 8.26 cases and 7.49 cases/1000 person-years, respectively; it was markedly increased in gout patients who used allopurinol for over 90 days. The hazard ratio of all-cause cancers was 1.21 (95% confidence interval=1.03-1.42, P=0.019) after adjustment for age and 2.26 for bladder cancer (95% confidence interval=1.32-3.87, P=0.003) on comparing those who used allopurinol for over 90 days with nonusers. Meanwhile, other cancers did not show the same significant result. We concluded that those who used allopurinol for a long duration had a higher occurrence of both bladder cancer and all-cause cancers in clinical evidence.

Role of N-linked glycans in the interactions of recombinant HCV envelope glycoproteins with cellular receptors.

Hepatitis C virus (HCV) infection is a major cause of chronic hepatitis and hepatocellular carcinoma. It infects human liver cells through several cellular protein receptors including CD81, SR-BI, claudin-1, and occludin. Previous reports also show that lectin receptors can mediate HCV recognition and entry. The envelope proteins of HCV (E1 and E2) are heavily glycosylated, further indicating the possible roles of lectin receptor-virus interaction in HCV infection. However, there is limited study investigating the relationship of HCV envelope glycoproteins and lectin as well as non-lectin receptors. Here we used surface plasmon resonance to examine the binding affinity of different glycoforms of recombinant HCV envelope protein to receptors and inspected the infectivity and assembly of HCV pseudoparticles composed of different glycoforms of envelope proteins. Our results indicated that DC-SIGN, L-SIGN, and Langerin had higher affinity to recombinant HCV envelope proteins in the presence of calcium ions than non-lectin receptors, and envelope proteins with Man8/9 N-glycans showed approximate 10-fold better binding to lectin receptors than envelope proteins with Man5 and complex type N-glycans. Interestingly, comparing among glycoforms, recombinant envelope proteins with Man5 N-glycans showed the highest binding affinity when interacting with non-lectin receptors. In summary, the glycans on HCV envelope protein play a modulatory role in HCV assembly and infection and direct HCV-receptor interaction, which mediates viral entry in different cells. Receptors with high affinity to HCV envelope proteins may be considered as targets for development of a therapeutic strategy against HCV.

Monitoring the gestation period of rescued Formosan pangolin (Manis pentadactyla pentadactyla) with progesterone radioimmunoassay.

Eight species of pangolin have been identified in the world. However, understanding of pangolin reproductive biology has been limited to fragmentary records. In this study, the concentration of serum progesterone in three pregnant and two nonpregnant rescued female Formosan pangolins (Manis pentadactyla pentadactyla) was monitored using a commercial progesterone radioimmunoassay kit. During gestation, the serum progesterone of pregnant pangolins A, B, and C remained at 28.5-55 ng/ml (n = 31 samples), 10.9-50.1 ng/ml (n = 34), and 12.4 and 33.5 ng/ml with a peak at 47.6 ng/ml (n = 19), respectively, whereas the serum progesterone of nonpregnant pangolins D and E remained at 1.99 ± 1.62 ng/ml (n = 80) and 2.27 ± 1.64 ng/ml (n = 27), respectively. From this study, it was found that female pangolin weighing as low as 2.14 kg was already capable of reproduction. For pregnant pangolins to give birth to viable offspring, their body weight must increase significantly, 63.89 and 134.0% in the study, from the time of inception or early pregnancy until parturition. In addition, study has found that both viable offspring were born fully developed and exceeded 80 g in weight. The period of gestation was found to be as short as 318 or longer than 372 days. Therefore, the Formosan pangolin should only be able to reproduce once a year. This study is the first insight into hormone assay for determining the gestation period of pangolin. Further investigations on the same subject are necessary to establish criteria for the recognition of reproductive status in pangolins.

Adsorption mechanism of selenate and selenite on the binary oxide systems.

Removal of selenium oxyanions by the binary oxide systems, Al- or Fe-oxides mixed with X-ray noncrystalline SiO(2), was previously not well understood. This study evaluates the adsorption capacity and kinetics of selenium oxyanions by different metal hydroxides onto SiO(2), and uses X-ray absorption spectroscopy (XAS) to assess the interaction between selenium oxyanions and the sorbents at pH 5.0. The binary oxide systems of Al(III)- or Fe(III)-oxides mixed with SiO(2) were prepared, and were characterized for their surface area, point of zero charge (PZC), pH envelopes, X-ray diffraction analysis (XRD), and then macro-scale adsorption isotherm and kinetics of selenite and selenate, micro-scale adsorption XAS. The adsorption capacity of selenite and selenate on Al(III)/SiO(2) is greater than on Fe(III)/SiO(2). Adsorption isothermal and kinetic data of selenium can be well fitted to the Langmuir isotherm and pseudo-second-order kinetic models. Based on simple geometrical constraints, selenite on both the binary oxide systems forms bidentate inner-sphere surface complexes, and selenate on Fe(III)/SiO(2) forms stronger complexes than on Al(III)/SiO(2).

Elucidation of ATP-stimulated stress protein expression of RBA-2 type-2 astrocytes: ATP potentiate HSP60 and Cu/Zn SOD expression and stimulates pI shift of peroxiredoxin II.

ATP has been shown to mediate stress responses in the brain. The present study examined the ATP-stimulated stress protein expression of RBA-2 type-2 astrocytes. Our results revealed that ATP stimulated HSP60 expression in a dose- and time-dependent manner. The stimulation requires a minimal ATP concentration of 500 microM and high concentration of extracellular ATP (1 mM) stimulated a significant increase of HSP60 expression from 2 to 24 h. In addition, the ATP-stimulated HSP60 expressions were inhibited by inhibitors for protein kinase C (PKC) and phospholipase D (PLD), and by antioxidants, resveratrol, and catalase. Furthermore, ATP stimulated the expression of Cu/Zn superoxide dismutase (SOD). In addition, ATP and P2X7 receptor selective agonist BzATP also decreased mitochondria membrane potential measured by flow cytometry. To further examine the proteins involving in ATP-mediated stress responses, we conducted proteomic analysis. We found that RBA-2 astrocytes possess abundant peroxiredoxin II (Prx II), an antioxidant enzyme. ATP and exogenous H2O2 stimulated Prx II shifting from oxidized form to reduced form. Thus, we concluded that ATP potentiated the expression of HSP60 and Cu/Zn SOD, and decreased mitochondria membrane potential. In addition, RBA-2 astrocytes expressed Prx II that might also serve as a protective mechanism to control the concentration of reactive oxygen species.