Development of high‐strength fibers from aliphatic polyketones by melt spinning and drawing

We have investigated the formation of high‐strength, high‐modulus fibers from four aliphatic polyketone resins. One resin was a perfectly alternating copolymer of ethylene and carbon monoxide, while the other three were terpolymers containing up to 6 mol % propylene. The mechanical properties were measured as a function of processing conditions, and the structures of the filaments were characterized using birefringence, WAXS, SAXS, SEM, and thermal analysis. Fibers formed from all resins develop very high molecular orientations and a microfibrillar structure. Fibers having room temperature tenacities as high as 10 gpd (～1.1 GPa) were obtained. Tensile moduli reached values as high as 120 gpd (～13 GPa). The melting point of the fibers was primarily dependent on the composition of the resin, while the maximum strength and modulus were largely determined by the maximum draw ratio achieved. The maximum draw ratio achieved in the present experiments was greater for the terpolymers than for the copolymer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1794–1815, 2001     

Harnessing Split-Inteins as a Tool for the Selective Modification of Surface Receptors in Live Cells

Biochemical studies of integral membrane proteins are often hampered by low purification yields and technical limitations such as aggregation causing in vitro manipulations to be challenging. The ability of controlling proteins in live cells bypasses these limitations while broadening the scope of accessible questions owing to the proteins being in their native environment. Here we take advantage of the intein biorthogonality to mammalian systems, site specificity, fast kinetics, and auto-processing nature as an attractive option for modifying surface proteins. Using EGFR as a model, we demonstrate that the split-intein pair Ava^N/Npu^C can be used to efficiently and specifically modify target membrane proteins with a synthetic adduct for downstream live cell application.     

Reconstruction of nasal defects with implant-retained nasal prostheses

BACKGROUND: Exercise testing with multigated acquisition technetium radionuclide cineangiography (MUGA) is a useful modality that can discriminate systolic and diastolic performance in patients with ischemic heart disease. However, some patients may have abnormal left ventricular filling dynamics with normal regional and global systolic function. HYPOTHESIS: The purpose of the study was to assess exercise-induced diastolic dysfunction as expressed by a prominent atrial (A) wave or diastasis deflection at the left ventricular volume curve, in patients with different degrees of ischemic heart disease. METHODS: In all, 32 men and 7 women aged 35-70 years (mean 54 +/- 8.6 years) underwent MUGA at rest and during exercise for analysis of the radionuclide volume curve. Within 6 weeks, thallium-201 scintigraphy and coronary angiography were performed and the patients were categorized into three groups: (1) disease-free (n = 10), (2) single-vessel disease (> 50% stenosis) (n = 19), and (3) double-vessel disease or more (n = 10). A waves or diastasis deflections were compared among the groups. RESULTS: Significant differences (p < 0.01) were noted in A-wave deflection relative to peak diastolic volume curve during exercise (Aexe/T) between Group 1 and Groups 2 and 3. Group 1 manifested only a mild rise in A-wave deflection from rest (20.20 +/- 8.49%) to exercise (25.85 +/- 8.49%), whereas Groups 2 and 3 exhibited a significant increase from 25.89 +/- 9.55% and 28.40 +/- 12.6%, respectively, to 60.21 +/- 22.5% and 63.0 +/- 22.86%, respectively. Group 2 had a significantly (p < 0.05) higher maximal heart rate than Group 3. CONCLUSIONS: The addition of prominent A-wave or diastasis deflection to a normal systolic response during exercise testing with multigated radionuclide cineangiography might be a sensitive marker of coronary artery disease. The A wave represents diastolic dysfunction of the left ventricle, considered an early event in the ischemic cascade.     

Graph-directed modelling from serial sections

We propose a general 3D-surface reconstruction technique for objects defined in terms of contours in a stack of serial sections. It is built around a data structure, in which the topology of the objects is represented as a set of disconnected graphs. The basic idea is to let the topological information direct the reconstruction process. There are several advantages with this approach. The alignment of the stack of sections is computed automatically. This operation does not depend on artificial reference points, such as fiduciary marks introduced by laser-beam penetration of a biological sample prior to sectioning. Furthermore, the unknown surfaces between successive sections can be created automatically, even though the sections contain a large number of arbitrarily shaped contours that are clustered or perhaps partly overlapped. If present, 3D irregularities in the surface model can be reduced in a controlled manner.     

Solar radiation on Mars

Detailed information on solar radiation characteristics on Mars are necessary for effective design of future planned solar energy systems operating on the surface of Mars. In this paper we present a procedure and solar radiation related data from which the diurnally, hourly and daily variation of the global, direct beam and diffuse insolation on Mars are calculated. The radiation data are based on measured optical depth of the Martian atmosphere derived from images taken of the sun with a special diode on the Viking cameras; and computation based on multiple wavelength and multiple scattering of the solar radiation.     

Differences in body composition of black and white girls

Adults have racial differences in body composition that may modulate risks resulting from obesity. Although black and white children have been shown previously to have differences in bone mineral density and subcutaneous body fat, differences in visceral adipose tissue have not been evaluated. We studied 20 black and 20 white normal-weight girls aged 7-10 y, who were matched for weight, body mass index (BMI), bone age, chronological age, Tanner breast stage, and socioeconomic status. Each underwent anthropometric measurements, bioelectrical impedance analysis, dual-energy X-ray absorptiometry (DXA), and abdominal magnetic resonance imaging (MRI) for determination of total (TAT), visceral (VAT), and subcutaneous (SAT) adipose tissue. Serum lipids and fasting and 2-h oral-glucose-tolerance test (OGTT) glucose and insulin concentrations were also measured. There were no differences between groups in absolute waist circumference or waist-to-hip ratio, but waist-to-thigh ratio was smaller in black than in white girls. Black girls had greater bone mineral density and less TAT, VAT, and SAT than whites. VAT was not significantly correlated with any measure of insulin, or with serum lipids. However, both basal and 2-h OGTT serum insulin were significantly correlated with SAT as assessed by MRI in black girls (r2 = 0.46 for basal insulin, P = 0.001: r2 = 0.31 for 2-h insulin, P = 0.01) but not in white girls (r2 < 0.05, for basal and 2-h insulin, NS). We conclude that there are significant racial differences in body composition and differences in the strength of association between abdominal adipose tissue depots and insulin sensitivity in black and white girls.     

Digital multiplex telephone transmission system using statistical properties of speech

A digital multiplex telephone transmission system is proposed, which should achieve a smaller bandwidth than conventional pulse-code modulation by using the statistical properties of speech waveforms. Each frame of transmitted pulses only contains a coded sample for a channel if the sample differs from the previous one from that channel. The frame can thus contain fewer time slots than there are channels, if there is a high probability of baseband signals changing by less than one quantising level during the frame period.     

CRITICAL SYSTEMS THINKING AND TOTAL SYSTEMS INTERVENTION: SYSTEMS-BASED RESEARCH AND CONSULTANCY IN THE DEPARTMENT OF MANAGEMENT SYSTEMS AND SCIENCES,HULL UNIVERSITY,UK

This paper is a brief overview of the current achievements of a substantial research and consultancy program, which is reflected in our undergraduate and postgraduate taught courses, at the University of Hull, UK. Our ideas are based on critique, which has been found useful in developing an open and conciliatory approach to the diversity of systems-based problem-solving methods. We label this critical systems thinking. The diversity is shown to be a strength as opposed to the failed conception of fragmentation and isolation, which is a weakness. Ail of this is brought together in a pragmatized form, which then provides a creative approach to systems-based problem solving for our consultancy work. We label this total systems intervention.