Novel visible light-driven Nb-doped Ta3N5 sensitized/protected by PPy for efficient overall water splitting

We successfully synthesized niobium-doped tantalum nitride sensitized/protected by polypyrrole (NbTa₃N₅/PPy) for efficient overall photocatalytic water splitting to produce hydrogen and oxygen under visible light. Niobium as a dopant was incorporated into the Ta₃N₅ lattice to act as an intermediate band between the valence band (VB) and the conduction band (CB) of Ta₃N₅ to enhance the electron-hole pair separation efficiency, thereby enhancing its photocatalytic activity. PPy, a conducting polymer with an extended π-π* conjugated electron system, was used as a sensitizer to enhance the charge transfer efficiency for migration of the photogenerated electrons and holes to its surface to prevent the recombination of the pairs and thus increase their lifetime. The migration of the photogenerated holes to the PPy surface also prevented the self photocorrosion of Ta₃N₅ (via reaction between the generated holes and nitrides in Ta₃N₅) in the electrolyte solution and thus enhanced its stability. Therefore, the synthesized NbTa₃N₅/PPy photocatalyst exhibited very high photocatalytic activity and stability for overall water splitting to produce H₂ and O₂ even under visible light at production rates of 65.1 and 32.8 μmol g^?1cat. h^?1, respectively.     

Electron spectroscopy and microscopy applied to chemical and structural analysis of hair

The photolightening behavior of red hair was investigated. Red hair was found to lighten to a similar extent by irradiation from both ultraviolet (UV) and visible (VIS) light. Under the same irradiating conditions, blond hair was lightened by VIS light but did not lighten by UV light until it was washed after irradiation. These different photolightening behaviors of red and blond hair are supposed to be due to differences in their melanin compositions. The dominant type of melanin in red hair is pheomelanin; while blond hair investigated in the previous work contained both eumelanin and pheomelanin, with mainly eumelanin. Consequently, in this investigation, the photolightening behaviors of red and blond hair were compared to clarify the differences in photosensitivity between the two types of melanin. It has been proven that chemically intact melanin in red hair is considerably more photolabile to UV light than VIS light. Also, it is much more easily decomposed by UV light than melanin granules in blond hair, although they are both similarly decomposed by VIS light. This indicates that pheomelanin is far more sensitive to UV light than eumelanin, while these two types of melanin are similarly sensitive to VIS light. This leads to the following hypothetical photolightening mechanism of red hair: When UV light is irradiated on red hair, the light is absorbed by hair protein and attenuated before it reaches the melanin granules. However, since pheomelanin is highly sensitive to UV light, even the attenuated UV light decomposes the pheomelanin to some extent. As a result, UV light lightens red hair without the need for subsequent washing, in contrast to blond hair, which consists of mainly eumelanin.     

Microbial ecology of Vietnamese Tra fish (Pangasius hypophthalmus) fillets during processing

There are numerous factors that can have an impact on the microbial ecology and quality of frozen Pangasius hypophthalmus fillets during processing in Vietnam. The presence of spoilage bacteria along the processing line can shorten the shelf-life of thawed frozen fish products. Therefore, the spoilage microbiota throughout the processing chain of two companies (BC: large scale factory, chlorine-based process, BW: large scale factory, water-based process and SC: small scale factory, chlorine-based process) was identified by culture-dependent techniques and 16S rRNA gene sequencing. The microbiological counts were observed to be insignificantly different (p > 0.05) between BC and BW. Surprisingly, chlorine treated fillets from the SC line were revealed to have significantly higher microbial counts than potable water treated fillets at BW line. This was determined to be a result of temperature abuse during processing at SC, with temperatures even greater than 10 °C being recorded from skinning onwards. On the contrary, the microbiota related to spoilage for BC and BW lines was determined by 16S rRNA gene sequencing to be more diverse than that on the SC line. A total of 174 isolates, 20 genera and 38 species were identified along the processing chains. The genera Aeromonas, Acinetobacter, Lactococcus and Enterococcus were prevalent at various processing steps on all the processing lines evaluated. A diverse range of isolates belonging to the Enterobacteriaceae such as Providencia, Shigella, Klebsiella, Enterobacter and Wautersiella were isolated from fillets sampled on the SC line whereas Serratia was only observed on fillets sampled on the BC and BW lines. The results can be used to improve Good Manufacturing Practices for processed Pangasius fillets and to select effective measures to prolong the shelf-life of thawed Vietnamese Pangasius fillets products.     

Combined model for growing mechanism of carbon nanotubes using HFCVD: effect of temperature and molecule gas diffusion

Growth of a dense forest of vertically-aligned carbon-nanotubes (VA-CNTs) by a hot filament chemical vapor deposition (HFCVD) method was investigated. The growth of very pure VA-CNTs via the bottom growth mechanism was extremely fast during the initial few minutes, but it slowed down and reached the terminal height of a couple of millimeters. The different temporal variations of the VA-CNT height and growth rates corresponding to different growth stages indicated that a temperature-mediated thermodynamic model, precursor diffusion, and catalyst deactivation were responsible for the VA-CNT growth in respective stages.     

Effect of temperature and pH on the degradation of fructo-oligosaccharides

The degradation process of fructo-oligosaccharides has been studied in buffered solution affected by temperature and pH. The system has been incubated at 60, 70, 80, 90 and 100 oC; pH has been varied between 2.7 and 3.3. The carbohydrate compositions of the solution-samples have been analyzed by an accurate analytical method for oligosaccharide determination (HPLC with differential refractometric detection). Under acidic condition the hydrolysis of fructo-oligosaccharides is insignificant at 60 oC; however, already at 70–80 oC it is so considerable, that the amount of them could be bisected in 1–2 h. Meanwhile, all of the oligomers are degraded in 1–1.5 h at 90–100 oC. The increase of proton concentration of the solution makes degradation faster; however, there is a slighter effect of pH on the rate of hydrolysis than of temperature in the studied range. The rate of the changes in the value of average degree of polymerisation (DP_a) significantly depends on the temperature and pH.     

3D amoeboid migration of a eukaryotic cell in a fiber matrix

A basic event in amoeboid-type cell movement (ATCM) is extension of an exploratory cell protrusion called a pseudopod. ATCM of cells among the fibrous macromolecules of the extracellular matrix (ECM) is crucial to tissue development and wound healing, and a key process in immune response and cancer invasion. We studied ATCM by developing a computational model of pseudopod extension/retraction driving ECM sensing, cell-matrix adhesion, and cell translocation within the 3D ECM mesh. We were successful in producing a biomorphic ATCM motion cycle involving viscoelastic protrusion and attachment to ECM, cell body displacement, and cell detachment from old adhesion sites. The simulated trajectories were in general persistent random walks resembling ATCM patterns reported for patrolling immune cells and cancer cell invasion.     

Expression and characterization of an active and thermally more stable recombinant antifreeze polypeptide from ocean pout, Macrozoarces americanus, in Escherichia coli improved expression by the modification of the secondary structure of the mRNA

The cDNA clone coding for the ocean pout antifreeze polypeptide(AFP) was modified to improve translation of its mRNA in Escherichiacoli. A recombinant AFP (rAFP), MetLys-AFP-Lys, was expressedsuccessfully using the XPL promoter, and constituted 1–2%of total bacterial proteins. The rAFP was purified to homogeneityfrom the soluble fractions of bacterial extracts. Its identitywas confirmed by amino acid analysis, automated Edman degradation,immuno-blot and activity measurements. Although the rAFP isindistinguishable from the authentic AFP in its secondary structure,thermal hysteretic activity and the alteration of ice crystalstructure, it is, however, thermally more stable ({small tilde}4.5°Cincrease in T_m) and is more effective in inhibiting ice growthalong the a-axis. These investigations indicate that the extraamino acids in rAFP significantly improve the thermal stabilityand ice-binding activity of the polypeptide.     

Lignin in wheat internodes. Part 1: The reactivities of lignin units during alkaline nitrobenzene oxidation

The alkaline nitrobenzene procedure for determining lignin building units has been applied to wheat internodes. The effect of reaction time and temperature on the rate of reaction has been measured and the nature of the aldehyde and acid products determined by gas-liquid chromatography. Survival factors for individual phenolic compounds were determined and found to be in the range 0.85–4.99, and were constant for each compound under the reaction conditions (c 6 % nitrobenzene in 2 M NaOH, 170°C, 2 h in a stainless steel pressure vessel), optimised for maximum recovery of products using wood and wheat internode meals. The reaction products fiom 24 monomeric and dimeric lignin model compounds were quantitativety determined to provide information on the susceptibility of various lignin structures to alkaline nitrobenzene oxidation. The results of these and earlier studies by other authors suggest that at the higher temperature a heterolytic reaction mechanism is operating on nitrobenzene oxidation conditions. On nitrobenzene oxidation, ferulic and p-coumaric acids survived in amounts which allowed the procedure to be used, with appropriate correction factors, to determine the nature and amount of these cinnamic acids associated with walls of grasses.     

Climate Change Adaptation Indicators to Assess Wastewater Management and Reuse Options in the Mekong Delta, Vietnam

Climate change adaptation indicators have played a critical role in the increased understanding of potential climate change impacts. In this research, 6 climate change adaptation indicators were identified for Can Tho City in the Mekong Delta of Vietnam: (1) Rice production from wastewater during winter-spring crop; (2) % of irrigation water demand satisfied by treated wastewater; (3) % of nutrient demand satisfied by treated wastewater; (4) % remaining flow downstream of Can Tho in the Hau River; (5) environmental benefits; and (6) total investment cost for wastewater treatment. These indices were selected to assess various options/strategies for wastewater management and reuse in Can Tho City as a means to improve the City’s resilience to climate change. From an environmental perspective, this study shows the benefits for Can Tho City to set up a strategy to treat and reuse wastewater from catfish farming as the priority among four assessed scenarios with different climate change impact factors. It is concluded that adaptation can be assessed by the indicators because they can define whether adaptation policies and measures are implemented and whether vulnerability is reduced through effective actions.     

Synthesis of functionalized SBA-15 with ordered large pore size and its adsorption properties of BSA

SBA-15, mesoporous material, is a very excellent candidate for drug delivery system because its pore size is easy to control according to synthesis conditions and the presence of swelling agent. In this study, a known swelling agent, 1,3,5-trimethylbenzene (TMB), was used to increase the pore size with increased aging temperature and prolonged aging time. Furthermore, 3-aminopropyltriethoxysilane (APTES) was incorporated on SBA-15 surface via post synthesis method to separate protein effectively. The samples were characterized by X-ray diffraction (XRD), nitrogen adsorption and desorption analyses, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier Transform Infrared (FT-IR). Adsorption capacity increased with temperature at the isoelectric point (pI) of bovine serum albumin (BSA) regardless of the pore size of SBA-15 samples. Release studies were carried out in the range of pH from neutral to basic solution on unmodified and amine-modified samples. In addition, the adsorption mechanism was investigated by employing the pseudo-first order, pseudo-second order, and intraparticle diffusion models.