The development and investigation of a novel pulsatile heart assist device

Cardiovascular diseases (CVD) contributed to almost 30% of worldwide mortality; with heart failure being one class of CVD. One popular and widely available treatment for heart failure is the intra-aortic balloon pump (IABP). This heart assist device is used in counterpulsation to improve myocardial function by increasing coronary perfusion, and decreasing aortic end-diastolic pressure (i.e. the resistance to blood ejection from the heart). However, this device can only be used acutely, and patients are bedridden. The subject of this research is a novel heart assist treatment called the Chronic Intermittent Mechanical Support (CIMS) which was conceived to offer advantages of the IABP device chronically, whilst overcoming its disadvantages. The CIMS device comprises an implantable balloon pump, a percutaneous drive line, and a wearable driver console. The research here aims to determine the haemodynamic effect of balloon pump activation under in vitro conditions. A human mock circulatory loop (MCL) with systemic and coronary perfusion was constructed, capable of simulating various degrees of heart failure. Two prototypes of the CIMS balloon pump were made with varying stiffness. Several experimental factors (balloon inflation/deflation timing, Helium gas volume, arterial compliance, balloon pump stiffness and heart valve type) form the factorial design experiments. A simple modification to the MCL allowed flow visualisation experiments using video recording. Suitable statistical tests were used to analyse the data obtained from all experiments. Balloon inflation and deflation in the ascending aorta of the MCL yielded favourable results. The sudden balloon deflation caused the heart valve to open earlier, thus causing longer valve opening duration in a cardiac cycle. It was also found that pressure augmentation in diastole was significantly correlated with increased cardiac output and coronary flowrate. With an optimum combination (low arterial compliance and low balloon pump stiffness), systemic and coronary perfusions were increased by 18% and 21% respectively, while the aortic end-diastolic pressure (forward flow resistance) decreased by 17%. Consequently, the ratio of oxygen supply and demand to myocardium (endocardial viability ratio, EVR) increased between 33% and 75%. The increase was mostly attributed to diastolic augmentation rather than systolic unloading.

The preparation of a common technique for selecting counter flow and crossflow cooling towers

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Evaluation of new processes for the preparation of iron by gas/solid phase systems

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The development of a novel Bio-MEMS filtration chip for the separation of specific cells in fluid suspension

In the clinical/microbiological laboratory there are currently several ways of separating specific cells from a fluid suspension. Conventionally cells can be separated based on size, density, electrical charge, light-scattering properties, and antigenic surface properties. Separating cells using these parameters can require complex technologies and specialist equipment. This paper proposes new Bio-MEMS (microelectromechanical systems) filtration chips manufactured using deep reactive ion etching (DRIE) technology that, when used in conjunction with an optical microscope and a syringe, can filter and grade cells for size without the requirement for additional expensive equipment. These chips also offer great versatility in terms of design and their low cost allows them to be disposable, eliminating sample contamination. The pumping mechanism, unlike many other current filtration techniques, leaves samples mechanically and chemically undamaged. In this paper the principles behind harnessing passive pumping are explored, modelled, and validated against empirical data, and their integration into a microfluidic device to separate cells from a mixed population suspension is described. The design, means of manufacture, and results from preliminary tests are also presented. © IMechE 2007.

A highly emissive inorganic hexamolybdenum cluster complex as a handy precursor for the preparation of new luminescent materials

The synthesis and characterisation of a new, highly luminescent inorganic cluster complex, (Bu4N)2[Mo6I 8(NO3)6], are described. The complex possesses labile nitrato ligands and is therefore a useful precursor for the design of new luminescent materials. To exemplify this, functionalised polystyrene beads have been utilised as "polymeric ligands" to immobilise the molybdenum cluster complex. This journal is © the Partner Organisations 2014.

Preparation of a microporous silicon oximide gel from the reaction of tris(dimethylamino)silylamine with formamide and its pyrolytic conversion into a silicon oxynitride based glass

A high-surface-area silicon oximide-based gel [SiOC(H)=NSi]m[Si2N-C(H)=O]n[SiN(H)-C(H)=O]p[SiOC(H)=NH]q[SiNH]r[SiNH2]s[SiNMe2]t was prepared via a formamide-based aminolysis of tris(dimethylamino)silylamine, (Me2N)3SiNH2. The structure of the gel and the mechanism of formation are elucidated. Pyrolysis of the gel at 1000 °C under N2 flow gave an amorphous microporous oxynitride-based glass with a BET surface area of 195 m2 g−1. © The Royal Society of Chemistry 2005.

Novel sol–gel preparation of (P2O5)0.4–(CaO)0.25–(Na2O)X–(TiO2)(0.35−X) bioresorbable glasses (X = 0.05, 0.1, and 0.15)

Quaternary phosphate-based glasses in the P2O5–CaO–Na2O–TiO2 system with a fixed P2O5 and CaO content of 40 and 25 mol% respectively have been successfully synthesised via sol–gel method and bulk, transparent samples were obtained. The structure, elemental proportion, and thermal properties of stabilised sol–gel glasses have been characterised using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), 31P nuclear magnetic resonance (31P NMR), titanium K-edge X-ray absorption near-edge structure (XANES), fourier transform infrared (FTIR) spectroscopy, and differential thermal analysis (DTA). The XRD results confirmed the amorphous nature for all stabilized sol–gel derived glasses. The EDX result shows the relatively low loss of phosphorus during the sol–gel process and Ti K-edge XANES confirmed titanium in the glass structure is in mainly six-fold coordination environment. The 31P NMR and FTIR results revealed that the glass structure consist of mainly Q1 and Q2 phosphate units and the Ti4+ cation was acting as a cross-linking between phosphate units. In addition DTA results confirmed a decrease in the glass transition and crystallisation temperature with increasing Na2O content. Ion release studies also demonstrated a decrease in degradation rates with increasing TiO2 content therefore supporting the use of these glasses for biomedical applications that require a degree of control over glass degradation. These sol–gel glasses also offer the potential to incorporate proactive molecules for drug delivery application due to the low synthesis temperature employed.

Antagonistic effects of two novel GIP analogs, (Hyp3)GIP and (Hyp3)GIPLys16PAL, on the biological actions of GIP and longer-term effects in diabetic ob/ob mice

This study examines the actions of the novel enzyme-resistant, NH 2-terminally modified GIP analog (Hyp3)GIP and its fatty acid-derivatized analog (Hyp3)GIPLys16PAL. Acute effects are compared with the established GIP receptor antagonist (Pro3)GIP. All three peptides exhibited DPP IV resistance, and significantly inhibited GIP stimulated cAMP formation and insulin secretion in GIP receptor-transfected fibroblasts and in clonal pancreatic BRIN-BD11 cells, respectively. Likewise, in obese diabetic ob/ob mice, intraperitoneal administration of GIP analogs significantly inhibited the acute antihyperglycemic and insulin-releasing effects of native GIP. Administration of once daily injections of (Hyp 3)GIP or (Hyp3)GIPLys16PAL for 14 days resulted in significantly lower plasma glucose levels (P < 0.05) after (Hyp 3)GIP on days 12 and 14 and enhanced glucose tolerance (P < 0.05) and insulin sensitivity (P < 0.05 to P < 0.001) in both groups by day 14. Both (Hyp3)GIP and (Hyp3)GIPLys16PAL treatment also reduced pancreatic insulin (P < 0.05 to P < 0.01) without affecting islet number. These data indicate that (Hyp3)GIP and (Hyp 3)GIPLys16PAL function as GIP receptor antagonists with potential for ameliorating obesity-related diabetes. Acylation of (Hyp 3)GIP to extend bioactivity does not appear to be of any additional benefit. Copyright © 2007 the American Physiological Society.

Study of a novel type of the optical modes in VCSELs

We study novel side-emitting modes in VCSEL microcavities. These modes correspond to π-shaped propagation along the mesa diameter, reflection from angled mesa walls and bottom Bragg reflector. We believe this study of π-modes is important for optimization of VCSEL design for improvement of efficiency.

Preparation of a poly(L-lactide-co-caprolactone) copolymer using a novel tin(II) alkoxide initiator and its fiber processing for potential use as an absorbable monofilament surgical suture

A poly(L-lactide-co-caprolactone) copolymer, P(LL-co-CL), of composition 75:25 mol% was synthesized via the bulk ring-opening copolymerization of L-lactide and ε-caprolactone using a novel bis[tin(II) monooctoate] diethylene glycol coordination-insertion initiator, OctSn-OCH2CH2OCH2CH2O-SnOct. The P(LL-co-CL) copolymer obtained was characterized by a combination of analytical techniques, namely nuclear magnetic resonance spectroscopy, gel permeation chromatography, dilute-solution viscometry, differential scanning calorimetry, and thermogravimetric analysis. For processing into a monofilament fiber, the copolymer was melt spun with minimal draw to give a largely amorphous and unoriented as-spun fiber. The fiber's oriented semicrystalline morphology, necessary to give the required balance of mechanical properties, was then developed via a sequence of controlled offline hot-drawing and annealing steps. Depending on the final draw ratio, the fibers obtained had tensile strengths in the region of 200–400 MPa.

Synthesis of a novel and stable g-C3N4–Ag3PO4 hybrid nanocomposite photocatalyst and study of the photocatalytic activity under visible light irradiation

A facile and reproducible template free in situ precipitation method has been developed for the synthesis of Ag3PO4 nanoparticles on the surface of a g-C3N4 photocatalyst at room temperature. The g-C3N4–Ag3PO4 organic–inorganic hybrid nanocomposite photocatalysts were characterized by various techniques. TEM results show the in situ growth of finely distributed Ag3PO4 nanoparticles on the surface of the g-C3N4 sheet. The optimum photocatalytic activity of g-C3N4–Ag3PO4 at 25 wt% of g-C3N4 under visible light is almost 5 and 3.5 times higher than pure g-C3N4 and Ag3PO4 respectively. More attractively, the stability of Ag3PO4 was improved due to the in situ deposition of Ag3PO4 nanoparticles on the surface of the g-C3N4 sheet. The improved performance of the g-C3N4–Ag3PO4 hybrid nanocomposite photocatalysts under visible light irradiation was induced by a synergistic effect, including high charge separation efficiency of the photoinduced electron–hole pair, the smaller particle size, relatively high surface area and the energy band structure. Interestingly, the heterostructured g-C3N4–Ag3PO4 nanocomposite significantly reduces the use of the noble metal silver, thereby effectively reducing the cost of the Ag3PO4 based photocatalyst.

The use of sodium carboxymethylcellulose in the preparation of spray-dried proteins for pulmonary drug delivery

The use of sodium carboxymethylcellulose (NaCMC) as a spray-drying excipient in the preparation of inhalable formulations of proteins was investigated, using alkaline phosphatase as a model functional protein. Two spray-dried powders were investigated: a control powder comprising 100% (w/w) alkaline phosphatase and a test powder comprising 67% (w/w) NaCMC and 33% (w/w) alkaline phosphatase. Following physicochemical characterisation, the powders were prepared as both dry powder inhaler (DPI) and pressurised metered dose inhaler (pMDI) formulations. The aerosolisation performance of the formulations was assessed using a Multi-Stage Liquid Impinger, both immediately after preparation and over a 16-week storage period. Formulating the control powder as a DPI resulted in a poor fine particle fraction (FPF: 10%), whereas the FPF of the NaCMC-modified DPI formulation was significantly greater (47%). When the powders were formulated as pMDI systems, the control and NaCMC-modified powders demonstrated FPFs of 52% and 55%, respectively. Following storage, reduced FPF was observed for all formulations except the NaCMC-modified pMDI system; the performance of this formulation following storage was statistically equivalent to that immediately following preparation. Co-spray-drying proteins and peptides with NaCMC may therefore offer an alternative method for the preparation of stable and respirable pMDI formulations for pulmonary delivery. © 2010 Elsevier B.V.

Globalization and the Marginalization of Educational Purpose: Preparation of Workers and Citizens for the 21st Century and the Vision of Sustainable Futures

Human capital development remains a primary goal of modern schooling. This paper raises questions concerning the link between global economic needs and school-based human capital development. The primary mission of preparing students for the workplace may weaken other educational missions vital in achieving a more sustainable future for humanity.

Improving the Preparation of Teachers Wishing to Work in Two-Way Bilingual Education Programs: Listening to the Practitioners

Two-way bilingual school principals were interviewed to find out their views on staffing. Finding candidates proficient in Spanish to provide content area instruction in this language was their greatest challenge. They suggested that the university offer content courses taught in Spanish and courses focusing on the mechanics of the language.