Isolation of laccase gene-specific sequences from white rot and brown rot fungi by PCR

Degenerate primers corresponding to the consensus sequences of the copper-binding regions in the N-terminal domains of known basidiomycete laccases were used to isolate laccase gene-specific sequences from strains representing nine genera of wood rot fungi. All except three gave the expected PCR product of about 200 bp. Computer searches of the databases identified the sequence of each of the PCR products analyzed as a laccase gene sequence, suggesting the specificity of the primers. PCR products of the white rot fungi Ganoderma lucidum, Phlebia brevispora, and Trametes versicolor showed 65 to 74% nucleotide sequence similarity to each other; the similarity in deduced amino acid sequences was 83 to 91%. The PCR products of Lentinula edodes and Lentinus tigrinus, on the other hand, showed relatively low nucleotide and amino acid similarities (58 to 64 and 62 to 81%, respectively); however, these similarities were still much higher than when compared with the corresponding regions in the laccases of the ascomycete fungi Aspergillus nidulans and Neurospora crassa. A few of the white rot fungi, as well as Gloeophyllum trabeum, a brown rot fungus, gave a 144-bp PCR fragment which had a nucleotide sequence similarity of 60 to 71%. Demonstration of laccase activity in G. trabeum and several other brown rot fungi was of particular interest because these organisms were not previously shown to produce laccases.     

Catalytic activity of MnTUD-1 for liquid phase oxidation of ethylbenzene with tert-butyl hydroperoxide

Manganese was incorporated into silica matrix of TUD-1 using tetraethylene glycol (TEG) as the template. Three samples with Si/Mn ratio of 115, 44 and 18 were prepared and characterized by various techniques. MnTUD-1 is shown to be mesoporous with tetrahedrally coordinated Mn when Si/Mn?=?115; and nano-particles of manganese oxides are visible at higher loading of manganese (Si/Mn?=?44 and 18). The catalytic activity of MnTUD-1 was explored in the liquid-phase oxidation of ethylbenzene with tert-butylhydroperoxide (TBHP) as oxidant. Influence of various reaction parameters such as time, Si/Mn ratio, oxidant and solvent were studied. Finally the catalytic activity also compared with well-known microporous and mesoporous catalysts like MnAlPO-5, Mn containing MCM-41, MCM-48 and SBA-15.     

Unprecedented vibration damping with high values of loss modulus and loss tangent, exhibited by cement-matrix graphite network composite

This paper reports a material with unprecedented vibration damping ability, as shown by high values of both the loss tangent (vibration amplitude decay rate) and the loss modulus (energy dissipation ability, equal to the product of the storage modulus and the loss tangent) under flexure at 0.2 Hz at room temperature. The loss modulus (7.5 GPa) exceeds that of any previously reported material, including the best metal-based material, which suffers from a low loss tangent. The loss tangent (0.81) is comparable to or exceeds that of any previously reported material, including rubber, which suffers from a low loss modulus. This material is a cement-matrix graphite network composite containing 8 vol.% graphite and made by compressing a mixture of cement particles and exfoliated graphite, which binds by mechanical interlocking, followed by curing in water. The graphite network structure is supported by microscopy and the low electrical resistivity of the composite (0.04 Ω cm perpendicular to the compression direction and 0.5 Ω cm in the compression direction). The composite is much more conductive than the most conductive cement-matrix composite containing a conductive admixture. The high loss tangent is attributed to the graphite network, while the high storage modulus is attributed to the cement matrix.     

Structural, optical, FTIR and photoluminescence studies of CdS1?xSex thin films by chemical bath deposition method

The ternary CdS_1?xSe_x alloy thin films with the nominal composition of x?=?0.2, 0.4, 0.6 and 0.8 have been synthesized on glass substrate by chemical bath deposition (CBD) method at 80°C from aqueous solution. Crystalline phases and optical absorption of the films have been studied by X-ray diffraction and UV–visible spectrophotometer. Elemental composition of the CdS_1?xSe_x films was studied by the energy dispersive X-ray (EDX) analysis. The optical absorption and transmission studies revealed that CdS_1?xSe_x films had direct allowed transition with band gap energy decreased from 2.28 to 1.92?eV as thickness varied from 762.4 to 621.2?nm. The average crystalline size was calculated from X-ray line broadening and it is increased from 12.71 to 14.67?nm for x?=?0.2–0.8 which was confirmed by SEM studies. The substitution of Se concentrations into the Cd–S and Cd–S–Se lattice is confirmed by the increase of lattice parameters, FTIR and photoluminescence studies. The broad variation in the band gap of CdS_1?xSe_x thin films have potential applications in the field of optoelectronic devices.     

Synthesis of Li(1+x)V3O8 by chemical route and its characterization

Lithium trivanadate (Li(1+x)V3O8) nanorods have been synthesized by the simple polymer precursor route using the polymer, polyvinyl pyrrolidone (PVP) as the complexing agent. Thermal behavior of the precursor has been studied by the differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and differential thermal analysis (DTA) techniques. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) studies confirm the formation of the compound. High resolution scanning electron microscopy (HRSEM) analysis reveals the synthesized Li1.2V3O8 particles to be nanorods with an average diameter of 50 nm.     

Molecularly self-assembled nucleic acid nanoparticles for targeted in vivo siRNA delivery

Nanoparticles are used for delivering therapeutics into cells. However, size, shape, surface chemistry and the presentation of targeting ligands on the surface of nanoparticles can affect circulation half-life and biodistribution, cell-specific internalization, excretion, toxicity and efficacy. A variety of materials have been explored for delivering small interfering RNAs (siRNAs)--a therapeutic agent that suppresses the expression of targeted genes. However, conventional delivery nanoparticles such as liposomes and polymeric systems are heterogeneous in size, composition and surface chemistry, and this can lead to suboptimal performance, a lack of tissue specificity and potential toxicity. Here, we show that self-assembled DNA tetrahedral nanoparticles with a well-defined size can deliver siRNAs into cells and silence target genes in tumours. Monodisperse nanoparticles are prepared through the self-assembly of complementary DNA strands. Because the DNA strands are easily programmable, the size of the nanoparticles and the spatial orientation and density of cancer-targeting ligands (such as peptides and folate) on the nanoparticle surface can be controlled precisely. We show that at least three folate molecules per nanoparticle are required for optimal delivery of the siRNAs into cells and, gene silencing occurs only when the ligands are in the appropriate spatial orientation. In vivo, these nanoparticles showed a longer blood circulation time (t(1/2) ≈ 24.2 min) than the parent siRNA (t(1/2) ≈ 6 min).     

Scaring the Already Scared: Some Problems With HIV/AIDS Fear Appeals in Namibia

Fear appeals are often used in public health campaigns in Africa to prevent further spread of HIV/AIDS. Based on the extended parallel processing model framework (K. Witte, 1991), this research assessed the impact of such messages in a high-fear situation. A 2 (high threat, low threat) × 2 (high efficacy, no efficacy) experiment with a no-message offset control and efficacy-only conditions tested several predictions. Participants demonstrated high preexisting fear about HIV/AIDS. As a likely consequence, statistical equivalence tests indicated that messages' threat levels had little impact on perceptions of fear or on outcome measures such as attitudes, intentions, or behaviors. It is concluded that the use of fear appeals to persuade audience with high levels of preexisting fear is ill-advised and ineffective.     

pH Sensitive graft copolymers for zero order drug release: a mechanistic analysis

Aliphatic polyesters containing pendent unsaturation were synthesized by the polycondensation of a diol, dicarboxylic acid and glycidyl methacrylate. Grafting methacrylic acid (MAA) resulted in graft copolymers containing polyester backbone and MAA grafts. Depending on composition, the polymers swelled extensively and eroded or dissolved at near neutral pH but remained in collapsed state at acidic pH. Three representative drugs differing in solubility, viz., Diltiazem hydrochloride (DH), Indomethacin (IM) and Verapamil hydrochloride (VH) were released at constant rate from tablets made by compressing spray-dried microparticles. The release of DH at constant rate has been attributed to increase in diffusion coefficient of the drug from the swollen layer of matrix. The release of IM and VH at constant rate was governed by erosion and was enhanced in matrices which undergo dissolution. The release rate was enhanced with increasing MAA content and the frequency of grafts along the polyester backbone. Once a day dosage forms for drugs differing in solubility have been developed using a single polymer matrix which is easy to manufacture.     

Electrical and magnetic properties of poly(<Emphasis Type="Italic">m</Emphasis>-phenylenediamine)/NiFe<Subscript>2</Subscript>O<Subscript>4</Subscript> nanocomposites

Poly(m-phenylenediamine) (PmPD)/NiFe₂O₄ nanocomposites were synthesized by in situ oxidative polymerization containing two different ratios of NiFe₂O₄ nanoparticles (10 and 20%). Dielectric studies of PmPD/NiFe₂O₄ nanocomposites were carried out at different temperature and frequency. Dielectric constants of PmPD/NiFe₂O₄ nanocomposites vary with the concentration of NiFe₂O₄ nanoparticles. Magnetic measurements of NiFe₂O₄ nanoparticles and PmPD/NiFe₂O₄ nanocomposites showed that they have ferromagnetic behaviour at room temperature. The XRD patterns of PmPD/NiFe₂O₄ nanocomposites are confirming the incorporation of NiFe₂O₄ nanoparticles into PmPD polymer. Room temperature Mössbauer spectrum of NiFe₂O₄ nanoparticles demonstrated that the Fe is in 3+ oxidation state with cubic structure. The SEM image of PmPD shows sphere like morphology. TGA suggest that thermal stability of PmPD/NiFe₂O₄ nanocomposites is greater than PmPD.     

Ketoconazole‐conjugated ZnO nanoparticles based semi‐solid formulation and study their impacts on skin disease

In this study, the ketoconazole‐conjugated zinc oxide (ZnO) nanoparticles were prepared in a single‐step approach using dextrose as an intermediate compound. The physical parameters confirmed the drug conjugation with ZnO and their size was around 70–75 nm. The drug loading and in vivo drug release studies indicated that the –CHO group from the dextrose increase the drug loading up to 65% and their release kinetics were also studied. The anti‐fungal studies indicated that the prepared nanoparticles exhibit strong anti‐fungal activity and the minimum concentration needed is 10 mg/ml. The nanoparticles loaded semi‐solid gel was prepared using carbopol, methylparaben, propyl paraben and propylene glycol. The in vitro penetration of the ketoconazole‐conjugated nanoparticles was studied using the skin. The results indicated that the semi‐solid gel preparations influenced the penetration and also favoured the accumulation into the skin membrane. The veterinary clinical studies indicated that the prepared gel is highly suitable for treatment of Malassezia.Inspec keywords: II‐VI semiconductors, skin, biomedical materials, antibacterial activity, wide band gap semiconductors, drug delivery systems, nanomedicine, drugs, diseases, gels, nanofabrication, nanoparticles, zinc compounds, biomembranes, veterinary medicineOther keywords: strong anti‐fungal activity, propyl paraben, propylene glycol, semisolid gel preparations, skin membrane, veterinary clinical studies, semisolid formulation, skin disease, ketoconazole‐conjugated zinc oxide nanoparticles, single‐step approach, physical parameters, drug conjugation, drug loading, release kinetics, dextrose, in vivo drug release studies, carbopol, methylparaben, in vitro penetration, Malassezia, ZnO