Unlocking the Potential of Magnetotactic Bacteria as Magnetic Hyperthermia Agents

Magnetotactic bacteria are aquatic microorganisms that internally biomineralize chains of magnetic nanoparticles (called magnetosomes) and use them as a compass. Here it is shown that magnetotactic bacteria of the strain Magnetospirillum gryphiswaldense present high potential as magnetic hyperthermia agents for cancer treatment. Their heating efficiency or specific absorption rate is determined using both calorimetric and AC magnetometry methods at different magnetic field amplitudes and frequencies. In addition, the effect of the alignment of the bacteria in the direction of the field during the hyperthermia experiments is also investigated. The experimental results demonstrate that the biological structure of the magnetosome chain of magnetotactic bacteria is perfect to enhance the hyperthermia efficiency. Furthermore, fluorescence and electron microscopy images show that these bacteria can be internalized by human lung carcinoma cells A549, and cytotoxicity studies reveal that they do not affect the viability or growth of the cancer cells. A preliminary in vitro hyperthermia study, working on clinical conditions, reveals that cancer cell proliferation is strongly affected by the hyperthermia treatment, making these bacteria promising candidates for biomedical applications.     

A finite difference scheme for solving a three‐dimensional heat transport equation in a thin film with microscale thickness

Heat transport at the microscale is of vital importance in microtechnology applications. The heat transport equation is different from the traditional heat diffusion equation since a second‐order derivative of temperature with respect to time and a third‐order mixed derivative of temperature with respect to space and time are introduced. In this study, we develop a finite difference scheme with two levels in time for the three‐dimensional heat transport equation. It is shown by the discrete energy method that the scheme is unconditionally stable. The three‐dimensional implicit scheme is then solved by using a preconditioned Richardson iteration, so that only a tridiagonal linear system is solved each iteration. Numerical results show that the solution is accurate. Copyright © 2001 John Wiley & Sons, Ltd.     

Thermal conductivity,elastic modulus,and coefficient of thermal expansion of polymer composites filled with ceramic particles for electronic packaging

The effective thermal conductivity, elastic modulus, and coefficient of thermal expansion of epoxy resins filled with ceramic fillers like silica, alumina, and aluminum nitride were determined. The data obtained was compared with theoretical and semitheoretical equations in the literature that are used to predict the properties of two phase mixtures. It was found that Agari's model provided a good estimate of the composite thermal conductivity. The Hashin‐Shtrikman lower bound for composite modulus fits the modulus data fairly well at low concentrations of the filler. Also, it was found that the coefficients of thermal expansion of the filled composites lie in between Schapery's upper and lower bounds. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3396–3403, 1999     

Vinyl-ester-participated transesterification and curing on the physicochemical behavior of Coir-IV

In this article, we report the transesterification of coir with n-Butyl acrylate (BA) and methyl acrylate (MA) under appropriate reaction conditions using NaOH and/or pyridine (Py) as catalyst. The modified vinylog coir was subsequently cured with benzoylperoxide (BPO) in acetone at 50–60°C. The modified fibers were characterized by Fourier transform infrared (FTIR) spectroscopy. Transesterification and curing of transesterified coir lowered the percentage of moisture regain and imparted improved tensile strength and resistance to common chemical reagents. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2283–2291, 1997     

ENERGY PLANNING AND OPTIMIZATION MODEL FOR RURAL DEVELOPMENT—A CASE OF SUSTAINABLE AGRICULTURE

In this paper we present an optimization model (using Linear Programming) for sustainable agriculture development in the Chellampatti block of Madurai District, Tamil Nadu, Southern India. The model is developed based on the availability of various energy sources in the block, and the requirements of various human and agricultural activities. The model optimizes the distribution of land for cultivating various crops based on the block's energy resources limitations and also to meet the minimum energy requirements of human beings and animals with regard to cereal, pulses, oil seeds, sugar, vegetables, fuel and feed. It is also suggested that the model can be modified to suit the local conditions so that it can have universal application for sustainable agriculture development. It is shown that, by applying the model, the revenue of the block through agriculture can be increased from the existing per hectare income of Rs 17600 to Rs 27 175⋅8 through proper planning, even without the import of cereals and external input energies like chemical fertilizers, diesel and machinery. The model takes care of the environment and the agro-ecosystem of the villages so that ecological balance is maintained. The model is solved by the HYPER LINDO software package in a PC-AT computer environment. © 1997 by John Wiley & Sons, Ltd.     

Patterned microstructures formed with MeV Au implantation in Si(1 0 0)

Energetic (MeV) Au implantation in Si(1 0 0) (n-type) through masked micropatterns has been used to create layers resistant to KOH wet etching. Microscale patterns were produced in PMMA and SU(8) resist coatings on the silicon substrates using P-beam writing and developed. The silicon substrates were subsequently exposed using 1.5 MeV Au³⁺ ions with fluences as high as 1 × 10¹⁶ ions/cm² and additional patterns were exposed using copper scanning electron microscope calibration grids as masks on the silicon substrates. When wet etched with KOH microstructures were created in the silicon due to the resistance to KOH etching cause by the Au implantation. The process of combining the fabrication of masked patterns with P-beam writing with broad beam Au implantation through the masks can be a promising, cost-effective process for nanostructure engineering with Si.     

All complaints are not created equal: text analysis of open source software defect reports

As the use of Open Source Software (OSS) systems increases in the corporate environment, it is important to examine the maintenance process of these projects. OSS projects allow end users to directly submit reports in case of any operational issues. Timely resolution of these defect reports requires effective management of maintenance resources. This study analyzes the usefulness of the textual content of the defect reports as an early indicator of their resolution time. Text Mining techniques are used to categorize defect reports of five OSS projects. Significant variation in the defect resolution time amongst the resulting categories, for each of the sample projects, indicates that a text based classification of defect reports can be useful in early assessment of resolution time before source code level analysis. Such technique can assist in allocation of sufficient maintenance resources to targeted defects and also enable project teams to manage customer expectations regarding defect resolution times.     

The Genome of the Mimosoid Legume Prosopis cineraria,a Desert Tree

The mimosoid legumes are a clade of ~40 genera in the Caesalpinioideae subfamily of the Fabaceae that grow in tropical and subtropical regions. Unlike the better studied Papilionoideae, there are few genomic resources within this legume group. The tree Prosopis cineraria is native to the Near East and Indian subcontinent, where it thrives in very hot desert environments. To develop a tool to better understand desert plant adaptation mechanisms, we sequenced the P. cineraria genome to near-chromosomal assembly, with a total sequence length of ~691 Mb. We predicted 77,579 gene models (76,554 CDS, 361 rRNAs and 664 tRNAs) from the assembled genome, among them 55,325 (~72%) protein-coding genes that were functionally annotated. This genome was found to consist of over 58% repeat sequences, primarily long terminal repeats (LTR-)-retrotransposons. We find an expansion of terpenoid metabolism genes in P. cineraria and its relative Prosopis alba, but not in other legumes. We also observed an amplification of NBS-LRR disease-resistance genes correlated with LTR-associated retrotransposition, and identified 410 retrogenes with an active burst of chimeric retrogene creation that approximately occurred at the same time of divergence of P. cineraria from a common lineage with P. alba~23 Mya. These retrogenes include many biotic defense responses and abiotic stress stimulus responses, as well as the early Nodulin 93 gene. Nodulin 93 gene amplification is consistent with an adaptive response of the species to the low nitrogen in arid desert soil. Consistent with these results, our differentially expressed genes show a tissue specific expression of isoprenoid pathways in shoots, but not in roots, as well as important genes involved in abiotic salt stress in both tissues. Overall, the genome sequence of P. cineraria enriches our understanding of the genomic mechanisms of its disease resistance and abiotic stress tolerance. Thus, it is a very important step in crop and legume improvement.     

SCN5A Variants as Genetic Arrhythmias Triggers for Familial Bileaflet Mitral Valve Prolapse

Mitral valve prolapse (MVP) is a common valvular heart defect with variable outcomes. Several studies reported MVP as an underestimated cause of life-threatening arrhythmias and sudden cardiac death (SCD), mostly in young adult women. Herein, we report a clinical and genetic investigation of a family with bileaflet MVP and a history of syncopes and resuscitated sudden cardiac death. Using family based whole exome sequencing, we identified two missense variants in the SCN5A gene. A rare variant SCN5A:p.Ala572Asp and the well-known functional SCN5A:p.His558Arg polymorphism. Both variants are shared between the mother and her daughter with a history of resuscitated SCD and syncopes, respectively. The second daughter with prodromal MVP as well as her healthy father and sister carried only the SCN5A:p.His558Arg polymorphism. Our study is highly suggestive of the contribution of SCN5A mutations as the potential genetic cause of the electric instability leading to ventricular arrhythmias in familial MVP cases with syncope and/or SCD history.