Large-scale electrospinning of polymer nanofibers using needleless nozzle

In this study, we have demonstrated that a rotating metal wire coil can be used as a nozzle to electrospin nanofibers on a large-scale. Without using any needles, the rotating wire coil, partially immersed in a polymer solution reservoir, can pick up a thin layer of charged polymer solution and generate a large number of nanofibers from the wire surface simultaneously. This arrangement significantly increases the nanofiber productivity. The fiber productivity was found to be determined by the coil dimensions, applied voltage and polymer concentration. The dependency of fiber diameter on the polymer concentration showed a similar trend to that for a conventional electrospinning system using a syringe needle nozzle, but the coil electrospun fibers were thinner with narrower diameter distribution. The profiles of electric field strength in the coil electrospinning was calculated and showed concentrated electric field intensity on the wire surface.

Characterization of high fluid strain micro contractions to study the stress on biological fluids

Microfluidics has the potential to enhance the understanding of the biological fluids under strain, due to the laminar nature of the fluid and the possibility to mimic the real conditions. We present advances on charaterization of a microfluidic platform to study high strain rate flows in the transport of biological fluids. These advances are improvements on the reproduction of a  constant extensional strain rate using micro contractions and development of 3D numerical models. The micro geometries have been fabricated in polydimethyl siloxame (PDMS) using standard soft-lithography techniques with a photolithographically patterned mold. A comparison of some microcontractions with different funnel characteristics is presented. The Micro Particle Image Velocimetry technique has been applied to validate the numerical simulations. We demonstrate the use of microfluidics in the reproduction of a large range of controllable extensional strains that can be used in the study of the effect of flow on biological fluids.

Optical micro analysis in lab-on-a-chips

Lab-on-a-chips are microfluidic devices which include biological laboratory functions on a single chip. They offer great advantages in terms of speed of analysis, precision, low sample and reagent consumption and automation of analysis. An efficient detection method in lab-on-a-chips is essential for the detection and quantification of chemical and biological parameters under examination. This review paper focuses on the recent research on optical detection techniques for LOC applications. Furthermore, several emerging detection paradigms which are still being matured are covered in this paper. Also, an analysis of the performance of different optical detection methods is given.

Micro-blogging in the workplace

Micro-blogging services such as Twitter, Yammer, Plurk and Google Buzz have generated substantial interest among members of the business community in recent years. Many CEOs, managers and front-line employees have embraced micro-blogs as a tool for interacting with colleagues, employees, customers, suppliers and investors. Micro-blogs are considered a more informal channel than emails and official websites, and thus present a different set of challenges to businesses. As a positional paper, this paper uses a case study of a bogus Twitter account to emphasise security and ethical issues relating to (i) Trust, Accuracy and Authenticity of Information, (ii) Privacy and Confidentiality, and (iii) Scams and Frauds, when micro-blogs are used in the workplace. It also highlights the potential risks businesses are exposed to if employees use micro-blogs irresponsibly. The paper contributes to practice by providing suggestions on managing security and ethical risks associated with micro-blogging in the workplace. It contributes to research by building on existing research in trust and data privacy in electronic communication.

Architecture of supramolecular soft functional materials: from understanding to micro-/nanoscale engineering

This article gives an overview of the current progress of a class of supramolecular soft materials consisting of fiber networks and the trapped liquid. After discussing the up-to-date knowledge on the types of fiber networks and the correlation to the rheological properties, the gelation mechanism turns out to be one of the key subjects for this review. In this concern, the following two aspects will be focused upon: the single fiber network formation and the multi-domain fiber network formation of this type of material. Concerning the fiber network formation, taking place via nucleation, and the nucleation-mediated growth and branching mechanism, the theoretical basis of crystallographic mismatch nucleation that governs fiber branching and formation of three-dimensional fiber networks is presented. In connection to the multi-domain fiber network formation, which is governed by the primary nucleation and the subsequent formation of single fiber networks from nucleation centers, the control of the primary nucleation rate will be considered. Based on the understanding on the the gelation mechanism, the engineering strategies of soft functional materials of this type will be systematically discussed. These include the control of the nucleation and branching-controlled fiber network formation in terms of tuning the thermodynamic driving force of the gelling system and introducing suitable additives, as well as introducing ultrasound. Finally, a summary and the outlook of future research on the basis of the nucleation-growth-controlled fiber network formation are given.

The role of micro-organisms (staphylococcus aureus and Candida Albicans) in the pathogenesis of breast pain and infection in lactation women : study protocol

Background: The CASTLE (Candida and Staphylococcus Transmission: Longitudinal Evaluation) study will investigate the micro-organisms involved in the development of mastitis and “breast thrush” among breastfeeding women. To date, the organism(s) associated with the development of breast thrush have not been identified. The CASTLE study will also investigate the impact of physical health problems and breastfeeding problems on maternal psychological health in the early postpartum period.

Methods/Design: The CASTLE study is a longitudinal descriptive study designed to investigate the role of Staphylococcus spp (species) and Candida spp in breast pain and infection among lactating women, and to describe the transmission dynamics of S. aureus and Candida spp between mother and infant. The relationship between breastfeeding and postpartum health problems as well as maternal psychological well-being is also being investigated. A prospective cohort of four hundred nulliparous women who are at least thirty six weeks gestation pregnant are being recruited from two hospitals in Melbourne, Australia (November 2009 to June 2011). At recruitment, nasal, nipple (both breasts) and vaginal swabs are taken and participants complete a questionnaire asking about previous known staphylococcal and candidal infections. Following the birth, participants are followed-up six times: in hospital and then at home weekly until four weeks postpartum. Participants complete a questionnaire at each time points to collect information about breastfeeding problems and postpartum health problems. Nasal and nipple swabs and breast milk samples are collected from the mother. Oral and nasal swabs are collected from the baby. A telephone interview is conducted at eight weeks postpartum to collect information about postpartum health problems and breastfeeding problems, such as mastitis and nipple and breast pain.

Discussion: This study is the first longitudinal study of the role of both staphylococcal and candidal colonisation in breast infections and will help to resolve the current controversy about which is the primary organism in the condition known as breast thrush. This study will also document transmission dynamics of S. aureus and Candida spp between mother and infant. In addition, CASTLE will investigate the impact of common maternal physical health symptoms and the effect of breastfeeding problems on maternal psychological well-being.

Institutional analysis of strategic choice of micro, small, and medium enterprises : development of a conceptual framework

This paper presents a conceptual framework showing formal and informal institutions and their relationship with the strategic choice of micro, small, and medium enterprises (MSMEs) in a developing country setting. It emphasises how institutions at sub-national level (such as a region or city) influence the strategic orientations of MSMEs as many developing countries in Asia are undergoing decentralisation whereby sub-national government authorities are given more political, economic, fiscal, and administrative powers. Furthermore, it sheds more insights on the environmental (institutional) determinism-organisational (strategic) choice nexus. It offers propositions, questions as well as issues worth pursuing in empirical investigations in the future.

Assessing impact of micro finance on poverty alleviation - Bangladesh perspective

“Micro finance” or its major part “micro credit”, both used interchangeably, is an important institutional device for alleviating poverty of the poor people. Micro finance concept was first developed and initiated in Bangladesh in the late seventies with a view to help the people living below the poverty line. Since its inception to till date, there has been tremendous growth of organizations, known as MFIs (Micro Finance Institutions), in this field to deal with the micro finance/credit activities. Despite this, the poverty situation of the poor people who have already used the micro finance programs was not improved substantially. The few MFIs have their own programs to conduct survey on impact assessment of their individual micro credit activities. The present study will focus on the impact assessment of micro finance activities on some variables of poverty alleviation, the extent to which these programs helped loanees to become micro finance graduates and the relevant suggestions as to the success of the micro finance activities.

Dielectrophoresis of micro/nano particles using curved microelectrodes

Dielectrophoresis, the induced motion of polarisable particles in non-homogenous electric field, has been proven as a versatile mechanism to transport, immobilise, sort and characterise micro/nano scale particle in microfluidic platforms. The performance of dielectrophoretic (DEP) systems depend on two parameters: the configuration of microelectrodes designed to produce the DEP force and the operating strategies devised to employ this force in such processes. This work summarises the unique features of curved microelectrodes for the DEP manipulation of target particles in microfluidic systems. The curved microelectrodes demonstrate exceptional capabilities including (i) creating strong electric fields over a large portion of their structure, (ii) minimising electro-thermal vortices and undesired disturbances at their tips, (iii) covering the entire width of the microchannel influencing all passing particles, and (iv) providing a large trapping area at their entrance region, as evidenced by extensive numerical and experimental analyses. These microelectrodes have been successfully applied for a variety of engineering and biomedical applications including (i) sorting and trapping model polystyrene particles based on their dimensions, (ii) patterning carbon nanotubes to trap low-conductive particles, (iii) sorting live and dead cells based on their dielectric properties, (iv) real-time analysis of drug-induced cell death, and (v) interfacing tumour cells with environmental scanning electron microscopy to study their morphological properties. The DEP systems based on curved microelectrodes have a great potential to be integrated with the future lab-on-a-chip systems.

Mechanical behavior of nano-micro composite core spun yarns