441 research outputs found
A preface from Editor-in-Chief
No full textAn introduction from our Editor-in-Chief, Prof. Akon Higuchi launching Progress in Bioscience and Bioengineering</jats:p
A preface from Editor-in-Chief
No full textAn introduction from our Editor-in-Chief, Prof. Akon Higuchi launching Progress in Bioscience and Bioengineering</jats:p
Bioreduction of hexavalent chromium by Pseudomonas stutzeri L1 and Acinetobacter baumannii L2
No full textBioreduction of the very toxic hexavalent chromi- um ion [Cr(VI)] to the non-toxic trivalent chromium ion [Cr(III)] is a key remediation process in chromium- contaminated sites. In this study, we investigated the bioreduction of Cr(VI) by Pseudomonas stutzeri L1 and Acinetobacter baumannii L2. The optimum pH (5–10), tem- perature (27, 37 and 60 °C) and initial chromium Cr(VI) concentration (100–1000 mg L−1) for Cr(VI) reduction by strains L1 and L2 were determined using the diphenylcarbazide method. In the presence of L1 and L2, the bioreduction rate of Cr(VI) was 40–97 and 84–99%, respectively. The bioreduction of Cr(VI) by L2 was higher, reaching up to 84%—than that by L1. The results showed that strain L2 was able to survive even if exposed to 1000 mg L−1 of Cr(VI) and that this tolerance to the effects of Cr(VI) was linked to the activity of soluble enzyme fractions. Overall, A. baumannii L2 would appear to be a potent Cr(VI)-tolerant candidate for the bioremediation of chromium (VI)-contaminated wastewater effluent
The recent outbreaks of Zika virus: Mosquito control faces a further challenge
No full textThe recent outbreaks of Zika virus infection occurring in South America, Central America and the Caribbean, represent the most recent of four key arrivals of arboviruses in the Western Hemisphere over the last 20 years. Zika virus is mainly vectored by Aedes mosquitoes. The development of effective and eco-friendly mosquito control methods is required in order to minimize the negative effects of currently marketed synthetic pesticides, including multidrug resistance. In this scenario, natural product research can afford solutions as part of integrated pest management strategies. In this review, we focused on neem (Azadirachta indica) products as sources of cheap control tools of Aedes vectors. Current knowledge on the larvicidal, pupicidal, adulticidal and oviposition deterrent potential of neem-borne products against the arbovirus vectors Aedes aegypti and Aedes albopictus is reviewed. Furthermore, we considered the rising importance of neem extraction by-products as sources of bio-reducing agents for the synthesis of nanoformulated mosquitocides. The last section examined biosafety and nontarget effects on neem-borne mosquitocides in the aquatic environment. Overall, we support the employ of neem-borne molecules as an advantageous alternative to build newer and safer Aedes control tools, in the framework of Zika virus outbreak prevention
Neem (Azadirachta indica).Towards the ideal insecticide?
No full textPesticide resistance is going to change rapidly our antibiotics and insecticides arsenal. In this scenario, plant-derived natural products are considered valuable candidates to reverse this negative trend. Growing research attention is focused on neem (Azadirachta indica, Meliaceae), exploring the utility of its products as insecticides and antibiotics. In this review, we summarised the knowledge on neem oil and neem cake by-products in arthropod pest control, with special reference to mosquito vectors of public health importance. To the best of our knowledge, neem-borne products currently showed effective and eco-friendly features, including little non-target effects, multiple mechanisms of action, low cost, easy production in countries with limited industrial facilities. In particular, the potentiality of neem cake as ideal and affordable source of mosquitocidal compounds in anopheline and aedine control programmes is outlined. Overall, we propose the employ of neem-based products as an advantageous alternative to build newer and safer arthropod control tools
Modified Higuchi Model Applied to Permeation Prediction of Nanocomposite Membranes
No full textAbstractIn this work, the existing Higuchi models were used for the prediction of gas permeability through the nanocomposite membranes. Predicted values were compared with experimental results of permeability for polycarbonate/silica nanocomposite membranes. Based on the critical analysis of the models predictions and its deviations, the parameter that influences the permeation behavior has been identified. The results revealed that for any particular gas, the change of empirical Higuchi parameter exhibited a direct impact on the accuracy the model. Thus, a modified parameter was incorporated on the modified Higuchi model relating to the intrinsic properties of the penetrant gas. With the new proposed Higuchi model, appreciable predictions of gas permeability through polycarbonate/silica nanocomposite membranes were achieved. The calculated absolute average relative error for CO2, N2 and CH4 gas permeability were found to be 7.18%, 6.07%, and 6.14%, respectively. Their corresponding standard deviations were obtained as 2.53, 1.53 and 0.73 Comparing the existing Higuchi models predictions, the new proposed Higuchi model has resulted to a reduction in relative errors by 6.3% for CO2, 70.66% for N2, and 65.25% for CH4
Investigation of the Mechanism of β-Amyloid Fibril Formation by Kinetic and Thermodynamic Analyses
No full text[Transfer of Lease #1 to Minoru Higuchi], Carson Estate Company, September 18, 1946
No full textLease #1 transfer between Minoru Higuchi , J. H. Masuzumi and Carson Estate Company executed on September 18, 1946
In darkness and seclusion : rhetoric of madness and problems of modernity in the works of Higuchi Ichiyō (1872-1896)
No full textThe author attempts to analyse how madness is aestheticized and poeticized in the late novellas by Higuchi Ichiyō (1872-1896). While referring to the concept of illness as a metaphor as developed by Susan Sontag and applied to the Japanese context by Karatani Kōjin, the author elaborates on the evocative and symbolic images of madness in Ichiyō’s works. The possible correspondences between the analyzed metaphors and the discourse of modernity in Meiji Japan are also considered Higuchi
Fern-synthesized silver nanocrystals: Towards a new class of mosquito oviposition deterrents?
No full textMosquitoes act as vectors of devastating pathogens and parasites, representing a key threat for millions of humans and animals worldwide. Eco-friendly control tools are urgently required. We proposed a novel method of fern-mediated biosynthesis of silver nanoparticles (AgNP) using Dicranopteris linearis, acting as a reducing and capping agent. AgNP were characterized by UV–vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), zeta potential and particle size analysis. In mosquitocidal assays, the LC50 of D. linearis extract against Aedes aegypti ranged from 165.213 (larva I) to 255.055 ppm (pupa). LC50 of D. linearis-synthesized AgNP ranged from 18.905 (larva I) to 29.328 ppm (pupa). In the field, the application of D. linearis extract and AgNP (10 × LC50) led to 100% larval reduction after 72 h. Smoke toxicity experiments conducted against A. aegypti adults showed that D. linearis leaf-, stem- and root-based coils evoked mortality rates comparable to the permethrin-based positive control (58%, 47%, 34%, and 48% respectively). In ovicidal experiments, egg hatchability was reduced by 100% after treatment with 25 ppm of AgNP and 300 ppm of D. linearis extract. Interestingly, oviposition deterrent assays highlighted that 100 ppm of fern extract reduced oviposition rates of more than 65%, while 10 ppm of fern-fabricated AgNP reduced oviposition rates of more than 70% in A. aegypti (OAI were − 0.52 and − 0.55, respectively). Overall, our results highlighted that D. linearis-synthesized AgNP could be useful candidates to develop nano-formulated oviposition deterrents effective against dengue vectors
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