Select persulfate activation processes were demonstrated to initiate oxidation not reliant on sulfate radicals, although the underlying mechanism has yet to be identified. This study explored singlet ...oxygenation and mediated electron transfer as plausible nonradical mechanisms for organic degradation by carbon nanotube (CNT)-activated peroxymonosulfate (PMS). The degradation of furfuryl alcohol (FFA) as a singlet oxygen (1O2) indicator and the kinetic retardation of FFA oxidation in the presence of l-histidine and azide as 1O2 quenchers apparently supported a role of 1O2 in the CNT/PMS system. However, the 1O2 scavenging effect was ascribed to a rapid PMS depletion by l-histidine and azide. A comparison of CNT/PMS and photoexcited Rose Bengal (RB) excluded the possibility of singlet oxygenation during heterogeneous persulfate activation. In contrast to the case of excited RB, solvent exchange (H2O to D2O) did not enhance FFA degradation by CNT/PMS and the pH- and substrate-dependent reactivity of CNT/PMS did not reflect the selective nature of 1O2. Alternatively, concomitant PMS reduction and trichlorophenol oxidation were achieved when PMS and trichlorophenol were physically separated in two chambers using a conductive vertically aligned CNT membrane. This result suggested that CNT-mediated electron transfer from organics to persulfate was primarily responsible for the nonradical degradative route.
The effect of As(III) on the photocatalytic degradation of phenolic pollutants such as 4-chlorophenol (4-CP) and bisphenol A (BPA) in a suspension of platinized TiO2 (Pt/TiO2) was investigated. In ...the presence of As(III), the photocatalytic degradation of 4-CP and BPA was significantly enhanced, and the simultaneous oxidation of As(III) to As(V) was also achieved. This positive effect of As(III) on the degradation of phenolic pollutants is attributed to the adsorption of As(V) (generated from As(III) oxidation) on the surface of Pt/TiO2, which facilitates the production of free OH radicals (•OHf) that are more reactive than surface-bound OH radicals (•OHs) toward phenolic pollutants. The generation of •OHf was indirectly verified by using coumarin as an OH radical trapper and comparing the yields of coumarinOH adduct (i.e., 7-hydroxycoumarin) formed in the absence and presence of As(V). In repeated cycles of 4-CP degradation, the degradation efficiency of 4-CP gradually decreased in the absence of As(III), whereas it was mostly maintained in the presence of As(III), which was either initially present or repeatedly injected at the beginning of each cycle. The positive effect of As(III) on 4-CP degradation was observed over a wide range of As(III) concentrations (up to mM levels) with Pt/TiO2. However, a high concentration of As(III) (hundreds of μM) inhibited the degradation of 4-CP with bare TiO2. Therefore, Pt/TiO2 can be proposed as a practical photocatalyst for the simultaneous oxidation of phenolic pollutants and As(III) in industrial wastewaters.
The thermal and hydrothermal stabilities and the structural degradation characteristics of a supported ZIF-7 membrane were studied at various temperatures (423–673 K), H 2 O vapor concentrations ...(10–40 mol%), and metal oxide supports (alumina, silica–alumina, silica, magnesia). The α-Al 2 O 3 supported ZIF-7 membrane prepared by the seeding and secondary growth method exhibited a high H 2 permeance (4.0 × 10 −7 mol m −2 s −1 Pa −1 ) with high H 2 selectivities (∼10) over larger CO, CH 4 , and CO 2 gases at an elevated temperature of 573 K. The thermal stability of the membrane in a dry atmosphere was determined primarily by the intercrystalline grain boundaries on the ZIF-7 overlayer, exhibiting a high thermal stability at 573 K. However, considerable cracks developed through the grain boundaries at 673 K due to excessive thermal stress. It was found that the metal oxide supports markedly affect the hydrothermal stability of the ZIF membranes. The α-Al 2 O 3 supported membrane suffered from fatal hydrothermal degradation of the ZIF-7 membrane layer even at a relatively low temperature of 473 K, and structural degradation was facilitated as the temperature and H 2 O vapor concentration increased. Surface acid/base properties of the metal oxide supports had a critical impact on the stability of the membrane; the ZIF-7 structure exhibited severe hydrothermal degradation on the acidic Al 2 O 3 and SiO 2 –Al 2 O 3 supports. Conversely, the ZIF-7 crystalline structure remained intact on the neutral SiO 2 and basic MgO supports even under highly antagonistic hydrothermal conditions (573 K, 20 mol% H 2 O). These findings provide important new insights for the effective construction of ZIF membranes with improved structural stabilities under practically relevant thermal and hydrothermal operation conditions.
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•The oxidation of As(III) to As(V) on WO3 primarily proceeds through two-hole transfer.•OH radical scavengers had little effect on the oxidation rate of As(III) to As(V).•As(III) ...enhanced the photocurrent by reacting with hole.•As(III) on WO3 acts as an external charge recombination center.
The oxidation of arsenite (As(III)) to arsenate (As(V)) and the involved oxidants on tungsten trioxide (WO3) under visible light were mechanically investigated. Three oxidant species, valence-band hole (hvb+), hydrogen peroxide (H2O2), and hydroxyl radical (OH), can be generated on WO3 under visible light. However, As(III) was not oxidized to As(V) in the presence of H2O2. In addition, the oxidation rate of As(III) to As(V) was not reduced in the presence of OH scavenger. These results indicate that the oxidation of As(III) to As(V) is primarily initiated by hole, but both OH and H2O2 are little involved in As(III) oxidation to As(V). This hole-mediated oxidation of As(III) to As(V) on WO3 was further confirmed by X-ray photoelectron spectroscopy (XPS) analysis (i.e., the adsorption of As(III) on WO3) and photoelectrochemical measurement (i.e., the enhanced photocurrent by As(III) addition). Although OH is little involved in As(III) oxidation to As(V), the production of OH was reduced in the presence of As(III). This behavior implies that As(III) on WO3 acts as an external charge recombination center, where the oxidation of As(III) to intermediate As(IV) species by hole or OH is immediately followed by the reduction of As(IV) to As(III) by conduction-band electron (ecb–). Therefore, the direct oxidation of As(III) to As(V) by two-hole transfer can be proposed as the primary oxidation pathway of As(III) to As(V) on WO3 under visible light.
Gram-negative bacteria have an outer membrane inhibiting the entry of antibiotics. Porins, found within the outer membrane, are involved in regulating the permeability of β-lactam antibiotics. ...β-lactamases are enzymes that are able to inactivate the antibacterial properties of β-lactam antibiotics. Interestingly, porins and β-lactamase are found in outer membrane vesicles (OMVs) of β-lactam-resistant
and may be involved in the survival of susceptible strains of
in the presence of antibiotics, through the hydrolysis of the β-lactam antibiotic. In this study, OMVs isolated from β-lactam-resistant
and from mutants, lacking porin or β-lactamase, were evaluated to establish if the porins or β-lactamase in OMVs were involved in the degradation of β-lactam antibiotics. OMVs isolated from
deficient in β-lactamase did not show any degradation ability against β-lactam antibiotics, while OMVs lacking OmpC or OmpF showed significantly lower levels of hydrolyzing activity than OMVs from parent
. These data reveal an important role of OMVs in bacterial defense mechanisms demonstrating that the OmpC and OmpF proteins allow permeation of β-lactam antibiotics into the lumen of OMVs, and antibiotics that enter the OMVs can be degraded by β-lactamase.
We prepared and characterized flexible thermoelectric (TE) materials based on thin films of single-walled carbon nanotube (SWCNT) composites with polyvinylalcohol. While pristine SWCNTs incorporated ...in a polymer matrix generated a p-type TE material, chemical functionalization of SWCNTs by using polyethyleneimine produced an n-type TE material. TE modules made of both p- and n-type composite were fabricated to demonstrate TE voltage and power generation. A single p–n junction made of two composite strips containing 20wt.% of SWCNTs generated a high TE voltage of 92μV per 1K temperature gradient (ΔT). By combining five electrically connected p–n junctions an output voltage of 25mV was obtained upon the applying ΔT=50K. Furthermore, this module generated a power of 4.5nW when a load resistance matched the internal module resistance of 30kΩ. These promising results show the potential of TE energy conversion provided by the SWCNT composite films connected in scalable modules for applications that require light weight and mechanical flexibility.
In higher vertebrates, helper and cytotoxic T cells, referred to as CD4 and CD8 T lymphocytes, respectively, are mainly associated with adaptive immunity. The adaptive immune system in teleosts ...involves T cells equivalent to those found in mammals. We previously generated monoclonal antibodies (mAbs) against olive flounder (
) CD4 T cells, CD4-1 and CD4-2, and used these to describe the olive flounder's CD4 Tcell response during a viral infection. In the present study, we successfully produced mAbs against CD8 T lymphocytes and their specificities were confirmed using immuno-blotting, immunofluorescence staining, flow cytometry analysis andreverse transcription polymerase chain reaction (RT-PCR). The results showed that these mAbs are specific for CD8 T lymphocytes. We also investigated variations in CD4 and CD8 T cells populations, and analyzed the expression of immune-related genes expressed by these cells in fish infected with nervous necrosis virus or immunized with thymus dependent and independent antigens. We found that both CD4 and CD8 T lymphocyte populations significantly increased in these fish and Th1-related genes were up-regulated compared to the control group. Collectively, these findings suggest that the CD4 and CD8 T lymphocytes in olive flounder are similar to the helper and cytotoxic T cells found in mammals, and Th1 and cytotoxic immune responses are primarily involved in the early adaptive immune response against extracellular antigens.
The presence of CD4 T lymphocytes has been described for several teleost species, while many of the main T cell subsets have not been characterized at a cellular level, because of a lack of suitable ...tools for their identification, e.g., monoclonal antibodies (mAbs) against cell markers. We previously described the tissue distribution and immune response related to CD3ε and CD4-1 T cells in olive flounder (
) in response to a viral infection. In the present study, we successfully produce an mAb against CD4-2 T lymphocytes from olive flounder and confirmed its specificity using immuno-blotting, immunofluorescence staining, flow cytometry analysis and reverse transcription polymerase chain reaction (RT-PCR). Using these mAbs, we were able to demonstrate that the CD3ε T cell populations contain both types of CD4
cells, with the majority of the CD4 T cell subpopulations being CD4-1
/CD4-2
cells, determined using two-color flow cytometry analysis. We also examined the functional activity of the CD4-1 and CD4-2 cells in vivo in response to a viral infection, with the numbers of both types of CD4 T cells increasing significantly during the virus infection. Collectively, these findings suggest that the CD4 T lymphocytes in olive flounder are equivalent to the helper T cells in mammals in terms of their properties and function, and it is the CD4-2 T lymphocytes rather than the CD4-1 T cells that play an important role in the Th1 immune response against viral infections in olive flounder.
Spiking neural networks (SNNs) have been researched as an alternative to reduce the gap with the human brain in terms of energy efficiency, due to their inherent spare event‐driven characteristics ...from a hardware implementation perspective. However, they still face significant challenges in learning, compared to artificial neural networks (ANNs). Recently, several algorithms have been developed to narrow the performance gap between SNNs and ANNs, including features in spiking neurons that can reduce information loss in the membrane potential. Inspired by these advancements, the current study designs and measures a neuron circuit using 180 nm complementary metal‐oxide‐semiconductor (CMOS) technology to address this information loss. The proposed circuit successfully implements these features, and their performance is validated through simulation based on the measured data.
An integrate‐and‐fire (I&F) neuron circuit with soft‐reset and underflow allowing functionalities is proposed to enhance the performance of hardware spiking neural networks (SNNs). The output characteristics of the I&F neuron circuit are experimentally demonstrated. To evaluate the performance in real‐world application, high‐level SNN simulations, incorporating the measured data, are conducted for CIFAR‐10 classification.
Cytokine immunogene therapy is a promising strategy for cancer treatment. Interleukin (IL)-12 boosts potent antitumor immunity by inducing T helper 1 cell differentiation and stimulating cytotoxic T ...lymphocyte and natural killer cell cytotoxicity. IL-23 has been proposed to have similar but not overlapping functions with IL-12 in inducing Th1 cell differentiation and antitumor immunity. However, the therapeutic effects of intratumoral co-expression of IL-12 and IL-23 in a cancer model have yet to be investigated. Therefore, we investigated for the first time an effective cancer immunogene therapy of syngeneic tumors via intratumoral inoculation of oncolytic adenovirus co-expressing IL-23 and p35, RdB/IL23/p35. Intratumoral administration of RdB/IL23/p35 elicited strong antitumor effects and increased survival in a murine B16-F10 syngeneic tumor model. The levels of IL-12, IL-23, interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α) were elevated in RdB/IL23/p35-treated tumors. Moreover, the proportion of regulatory T cells was markedly decreased in mice treated with RdB/IL23/p35. Consistent with these data, mice injected with RdB/IL23/p35 showed massive infiltration of CD4(+) and CD8(+) T cells into the tumor as well as enhanced induction of tumor-specific immunity. Importantly, therapeutic mechanism of antitumor immunity mediated by RdB/IL23/p35 is associated with the generation and recruitment of IFN-γ- and TNF-α-co-producing T cells in tumor microenvironment. These results provide a new insight into therapeutic mechanisms of IL-12 plus IL-23 and provide a potential clinical cancer immunotherapeutic agent for improved antitumor immunity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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