The water flea Daphnia magna is a small freshwater planktonic animal in the Cladocera. In this study, we assembled the genome of the D. magna NIES strain, which is widely used for gene targeting but has no reported genome. We used the long-read sequenced data of the Oxford nanopore sequencing tool for assembly. Using 3,231 genetic markers, the draft genome of the D. magna NIES strain was built into ten linkage groups (LGs) with 483 unanchored contigs, comprising a genome size of 173.47 Mb. The N50 value of the genome was 12.54 Mb and the benchmarking universal single-copy ortholog value was 98.8%. Repeat elements in the D. magna NIES genome were 40.8%, which was larger than other Daphnia spp. In the D. magna NIES genome, 15,684 genes were functionally annotated. To assess the genome of the D. magna NIES strain for CRISPR/Cas9 gene targeting, we selected glutathione S-transferase omega 2 (GST-O2), which is an important gene for the biotransformation of arsenic in aquatic organisms, and targeted it with an efficient make-up (25.0%) of mutant lines. In addition, we measured reactive oxygen species and antioxidant enzymatic activity between wild type and a mutant of the GST-O2 targeted D. magna NIES strain in response to arsenic. In this study, we present the genome of the D. magna NIES strain using GST-O2 as an example of gene targeting, which will contribute to the construction of deletion mutants by CRISPR/Cas9 technology.

Morphological alterations and nuclear abnormalities in fish erythrocytes have been used in many studies as bio-indicators of environmental mutagens including ionizing radiation (IR) irradiation. In this study, adult Japanese medaka (Oryzias latipes) were irradiated with gamma-rays at a low dose rate (9.92 µGy/min) for 7 days, giving a total dose of 100 mGy, and morphological alterations, nuclear abnormalities and apoptotic cell death induced in peripheral erythrocytes were investigated 8 hours and 7 days after the end of the irradiation. A variety of the abnormality, such as tear-drop cell, crenated cell, acanthocyte, sickled cell, micronucleated cell, eccentric nucleus, notched nucleus, and schistocyte, were induced both in the peripheral erythrocytes of the wild-type fish and a less number of the abnormalities and apoptotic cell death were induced in the p53-deficient fish. These results indicate that low dose-rate chronic irradiation of gamma-rays can induce cytotoxic and genotoxic effects in peripheral erythrocytes of medaka and p53-deficient medaka are tolerant to the gamma-ray irradiation than the wild-type on the surface

The effects of Harness® toxicity on fish health are little known. So, current work aimed to study the impact of sub-lethal doses of Harness® (an acetochlor-based herbicide) on the African catfish, Clarias gariepinus, and also investigated the potential role of lycopene (LYCO) administration in alleviating Harness® negative effects. Fish were divided into five groups in triplicates as follows: group 1 (control) received no treatment, group 2 was exposed to 10 μm Harness®/L, group 3 was orally administered 10 mg LYCO/kg body weight and exposed to 10 μm Harness®/L, group 4 was exposed to 100 μm Harness®/L, and group 5 was orally administered 10 mg LYCO/kg body weight and exposed to 100 μm Harness®/L for 2 weeks. Some hemato-biochemical parameters, genotoxicity, and histopathological changes were assessed at the end of this period. Sub-lethal doses of Harness® altered the shape of erythrocytes in contrast to the control sample. Also, hematological parameters of exposed fish exhibited a significant (P < 0.05) reduction in the values of red blood cell count (RBCs), hemoglobin (Hb), hematocrit (HCT), and platelets (PL), as well as an insignificant (P > 0.05) drop in mean corpuscular volume (MCV). Harness® was also found to cause genotoxicity as well as histopathological alterations. LYCO administration decreased hemato-biochemical changes and returned them to near-normal levels. The findings showed that LYCO administration (10 mg LYCO/kg body weight) decreased Harness® toxicity in C. gariepinus and alleviated its destructive effects.

Combining both processing techniques of horizontal-to-vertical spectral ratio (HVSR) and surface-to-borehole spectral ratio (SBR), using the KiK-net and K-NET database in Japan, could be used in the present study to establish relationships of V_S and resonant frequency (ff) versus depth to bedrock half-space (hh) based on the site-dependent variability. Remarkable correlations of the average VsVs of layers overlying the bedrock half-space (VS¯¯¯¯¯¯VS¯) versus hh are inversely resembling those of the ff versus hh. The maximum VS¯¯¯¯¯¯VS¯ values are 1262 m/s, 933 m/s, 842 m/s, and 568 m/s through site class of B, C, D, and E, respectively. These values of VS¯¯¯¯¯¯VS¯ are decreasing gradually resembling the Vs30Vs30 through site class of B, C, D, and E according to (NEHRP, Report FEMA 368, NEHRP, Washington, 2000). The ff versus hh regressions at KiK-net sites yield gradual decrease in the correlation coefficients (i.e., a and b) through site class of B, C, D, and E, particularly the resulted a and b from SBR technique. K-NET sites yield significant lower correlation coefficients, which could be attributed to the K-NET shallow depths (hh) and their corresponding limited ranges of (ff). Although such relationships are site-specific and highly dependent on each region’s geologic conditions, fair comparisons based on site information and site-dependent variability between previous relationships of ff versus hh in the literature and the present study relationships are showing remarkable similarities. This indicates significant importance of introducing the seismic site classification as a crucial controlling factor in establishing the previous and the present VsVs and ff versus hhnonlinear regression relationships.

Water splitting via photocatalysis using titanium dioxide (TiO₂) holds great potential for hydrogen gas generation. Herein, zeolitic imidazolate framework (ZIF-67) was used as a sacrificial precursor for the synthesis of cobalt oxide embedded nitrogen doped carbon (Co₃O₄@C) that was used as a co-catalyst with TiO₂ for the hydrogen generation via photocatalytic water splitting. The optimal loading of Co₃O₄@C (7 wt%) exhibited a photocatalytic hydrogen production rate (HGR) of 11,400 µmol g⁻¹ h⁻¹. It demonstrated a 75-fold and 110-fold increase for cumulative (5 h) and initial hydrogen generation rates, respectively. The electrochemical measurements such as cyclic voltammetry (CV), linear scan voltammetry (LSV), electrochemical independence spectroscopy (EIS) using Nyquist plots, and photocurrent response were conducted to evaluate the catalytic performance of Co₃O₄@C/TiO₂. Transient photocurrent response showed significant enhancement (4-fold) in photocurrent density of TiO₂. Co₃O₄@C promoted the photocatalytic performance of TiO₂ and improved the HGR. The photocatalysis using Co₃O₄@C/TiO₂ is recyclable for more than four cycles without significant loss of their performance. The results of our study may open the door for further exploration toward effective photocatalyst.

In the present work we report the sol-gel synthesis of pure TiO₂ and (TiO₂)_1−x(Fe₂O₃)_x nanocomposites with different Fe₂O₃ contents (x = 0, 0.1, 0.5, and 1.0 for pure TiO₂, Fe₂O₃ incorporated 0.1, 0.5, and pure Fe₂O₃ which are denoted as PT, 0.1F, 0.5F, and PF, respectively). The structural, morphological, optical, and surface texture of the prepared nanocomposites were characterized using various techniques. The structural studies confirm the strong influence of Fe₂O₃ contents on the crystallite sizes and dislocation values. The size of the crystallites was increased by the increase in Fe₂O₃ contents. The bandgap values elucidated from DRS analysis were decreased from 3.15 eV to 1.91 eV with increasing Fe₂O₃ contents. The N₂-Physorption analysis has confirmed the mesoporous nature of the samples with a comparable specific surface area of 35 m²/g. The photoelectrochemical measurements (CV, CA and EIS) were performed to assess the photoelectric properties of the prepared materials. It was found that the PT samples have the highest catalytic activity and photocurrent response compared to other composites. The reduction in current density was as follows: 2.8, 1.65, 1.5 and 0.9 mA/cm², while the photocurrent response was ca. 800, 450, 45, 35 µA/cm² for PT, 0.1F, 0.5F and PF samples, respectively. The EIS results showed that the (TiO₂)_1−x(Fe₂O₃)_x nanocomposites exhibit lower charge transfer resistance than pure titania and hematite samples.

Fischer–Tropsch has become an indispensable choice in the gas-to-liquid conversion reactions to produce a wide range of petrochemicals using recently emerging biomass or other types of feedstock such as coal or natural gas. Herein we report the incorporation of novel Cu nanoparticles with two Fischer–Tropsch synthesis (FTS) catalytic systems, Fe/reduced graphene oxide (rGO) and Fe–Mn/rGO, to evaluate their FTS performance and olefin productivity in two types of reactors: slurry-bed reactor (SBR) and fixed-bed reactor (FBR). Four catalysts were compared and investigated, namely Fe, FeCu₇, FeMn₁₀Cu₇, and FeMn₁₆, which were highly dispersed over reduced graphene oxide nanosheets. The catalysts were first characterized by transmission electron microscopy (TEM), nitrogen physisorption, X-ray fluorescence (XRF), X-ray diffraction (XRD), and H-TPR techniques. In the SBR, Cu enhanced olefinity only when used alone in FeCu₇ without Mn promotion. When used with Mn, the olefin yield was not changed, but light olefins decreased slightly at the expense of heavier olefins. In the FBR system, Cu as a reduction promoter improved the catalyst activity. It increased the olefin yield mainly due to increased activity, even if the CO₂ decreased by the action of Cu promoters. The olefinity of the product was improved by Cu promotion but it did not exceed the landmark made by FeMn₁₆ at 320 °C. The paraffinity was also enhanced by Cu promotion especially in the presence of Mn, indicating a strong synergistic effect. Cu was found to be better than Mn in enhancing the paraffin yield, while Mn is a better olefin yield enhancer. Finally, Cu promotion was found to enhance the selectivity towards light olefins C2–4. This study gives a deep insight into the effect of different highly dispersed FTS catalyst systems on the olefin hydrocarbon productivity and selectivity in two major types of FTS reactors.

Rational design and fabrication of effective multi-component cocatalyst for high performance photocatalytic hydrogen production via water-splitting have been investigated. Herein, polyaniline-derived N-doped carbon encapsulated copper/copper phosphide nanoparticles (Cu/Cu_xP@NC) was facilely prepared by a single-step phosphorization-pyrolysis route. Homologous Cu/Cu_xP heterostructure with a diameter ∼ 20 nm was successfully wrapped with N-doped carbon layers. The resultant Cu/Cu_xP@NC is utilized as a cocatalyst of host photocatalysts like TiO₂ and g-C₃N₄ for H₂ generation. The optimal Cu/Cu_xP@NC/TiO₂ composites exhibited a hydrogen evolution rate (HER) of 12.45 mmol.h⁻¹ g⁻¹ which is 145-fold higher than TiO₂ alone. Interestingly, the Cu/Cu_xP@NC composite also improved the activity of g-C₃N₄ to produce 285 µmol.h⁻¹ g⁻¹ of H₂ under visible light where no H₂ was evolved over pure g-C₃N_4. The photocatalytic performance of the presented Cu/Cu_xP@NC/TiO₂ was superior than carbon-free Cu/Cu_xP/TiO₂ nanocomposite. Such improved activity is attributed to the N-doped carbon layer that plays a pivotal role in suppressing the recombination of the photogenerated electron-hole pairs. Thus, Cu/Cu_xP@NC cocatalyst composite can efficiently capture the photoexcited electrons from the conduction band of TiO₂ or g-C₃N₄, accelerating the charge separation process. This study provides a low-cost and competitive cocatalyst to substitute noble metals in photocatalytic reactions.

Photocatalytic Hydrogen production via water splitting is considered a sustainable ecofriendly pathway to replenish the current and future energy demands. In this study, the self-assembly synthesis of Cu nanospheres (∼8 nm) surrounded by a thin conductive layer of polyaniline (Cu@PANI) was rationally engineered via in˗situ polymerization. Afterward, it was successfully deposited onto the TiO₂ surface to improve the photocatalytic activities for hydrogen production. The optimal Cu@PANI/TiO₂ ternary photocatalyst produced a substantial hydrogen generation rate (HGR) of 17.7 mmol h⁻¹ g⁻¹, 207-fold higher than that of bare TiO₂. The performance was considerably improved compared with (Cu–TiO₂)/PANI and (PANI-TiO₂)/Cu composites prepared by changing the deposition sequence of Cu and PANI. Such an improved activity was because of multiple transferring paths of photogenerated electrons in the composite. Interestingly, the as-prepared ternary photocatalyst exhibited superior hydrogen evolution compared with the binary hybrids (Cu/TiO₂ and PANI/TiO₂). The exceptional performance of Cu@PANI/TiO₂ could be understood considering the distinctive electrical conductivity of PANI and heterojunction formed between PANI and TiO₂, as well as the merits of the Schottky junction constructed between Cu and PANI. These superior features could efficiently suppress the recombination rate of the photogenerated electron–hole pairs and maximize the photocatalytic activity. This study provides new insights for understanding the effect of electron transfer pathways on photocatalytic activities.