Intraventricular chemotherapy in neonatal meningitis

All of 16 infants with neonatal meningitis treated during a 30-month period were found to have accompanying ventriculitis at the time of the initial ventricular puncture. Fifteen of these infants were caused by gramm-negative organisms. All infants received antibiotics systemically and intraventricularly via an implanted ventriculostomy reservoir or by direct ventricular injection. Antibiotic concentrations within the ventricular fluid were monitored during chemotherapy; the complications encountered during treatment are discussed. Fifteen infants survived the infection; of these, seven infants were normal at follow-up examinations. In our experience intraventricular chemotherapy as an adjunct to systemic administration of antibiotics has greatly reduced the mortality rate in neonatal meningitis.     

Changes in the phase structure and formation of chemical compounds by ion implantation of tantalum thin films

Evaporated films of tantalum+tantalum oxide, 500 Å thick, were implanted with argon, oxygen and nitrogen ions. The phase structure of the films was determined by transmission electron microscopy and the dose dependence of resistivity and thermal coefficient of resistivity was satisfactorily explained in terms of the precipitation of compounds formed in the film. Argon bombardment had little effect on the structure of a film until sputter etching had reduced the film thickness considerably, when precipitates of TaO₂ in the form of rounded islands were created. Oxygen bombardment resulted in the precipitation of the b.c.c. phase of tantalum, and at higher doses precipitates of TaO₂ were formed. Nitrogen bombardment resulted in a sudden phase change and the precipitation of Ta₄N₅ in the form of hexagonal platelets; the conduction process in these films was highly activated, probably as a result of the presence of an amorphous oxide matrix. The dependence of changes in electrical properties on oxygen content of the film is explained by this phase structure.     

Electron-acoustic and surface electron beam induced voltage signal formation in scanning electron microscopy analysis of semiconducting samples

The conditions for the detection of electron-acoustic (EA) and surface electron beam induced voltage (SEBIV) signals using a common sample mount and bottomside detection scheme are hereby discussed. It is shown that while the intrinsic properties of the sample under electron-beam irradiation would chiefly determine the presence of these contrast mechanisms, the manner in which the sample is mechanically and electrically configured in relation to the signal detection is crucial in determining the actual signal coupling mechanisms at work and hence the assumptions by which a robust and consistent interpretation of experimental results can be made. EA signals are detectable only if electrical coupling between the sample and the detector is defeated, a necessary pre-requisite as the signal magnitude of carrier-generated SEBIV coupling is 2-3 orders larger in most cases. With regards to SEBIV detection, bottomside SEBIV detection may be preferable to topside detection owing to minimization of topographic signal contribution, higher signal coupling efficiency and a less complex sample-detector mounting procedure.     

Static and dynamic pressure profiles of a patellar-tendon-bearing (PTB) socket

The purpose of this study was to evaluate the pressure distribution at the stump/socket interface in amputees wearing the patellar-tendon-bearing socket. A specially built strain gauged type pressure transducer was used for measuring this pressure distribution in four unilateral transtibial amputees. Pressure and gait parameters were measured simultaneously while they were standing and walking. Pressure profiles were compiled at 10, 25 and 50 per cent of gait cycle and compared with the pressure profiles predicted by Radcliffe in 1961. The subject's anterior-posterior pressure profiles were different from each other. However, at toe-off, each subject exhibited an increase in pressure at the patellar tendon. Their medial-lateral pressure profiles were similar: exhibiting high pressure at the medial proximal and lateral distal regions except for one subject who exhibited high pressure at the lateral proximal region instead. The subjects' pressure profiles did not resemble Radcliffe's anticipated pressure profiles. This was because ground reaction force was not the only factor affecting the resulting pressure profiles.     

A multiobjective memetic algorithm based on particle swarm optimization.

In this paper, a new memetic algorithm (MA) for multiobjective (MO) optimization is proposed, which combines the global search ability of particle swarm optimization with a synchronous local search heuristic for directed local fine-tuning. A new particle updating strategy is proposed based upon the concept of fuzzy global-best to deal with the problem of premature convergence and diversity maintenance within the swarm. The proposed features are examined to show their individual and combined effects in MO optimization. The comparative study shows the effectiveness of the proposed MA, which produces solution sets that are highly competitive in terms of convergence, diversity, and distribution.     

Mechanical Reinforcement of Polyethylene Using Polyethylene‐Grafted Multiwalled Carbon Nanotubes

The incorporation of carbon nanotubes to a polymer generally improves the stiffness and strength of the polymer, but the ductility and toughness of the polymer are compromised in most cases. Here we report the mechanical reinforcement of polyethylene (PE) using polyethylene‐grafted multiwalled carbon nanotubes (PE‐g‐MWNTs). The stiffness, strength, ductility and toughness of PE are all improved by the addition of PE‐g‐MWNTs. The grafting of PE onto MWNTs enables the well‐dispersion of nanotubes in the PE matrix and improves MWNT/PE interfacial adhesion. The grafting was achieved by a reactive blending process through melt blending of PE containing 0.85 wt % of maleic anhydride and amine‐functionalized MWNTs. The reaction between maleic anhydride and amine groups, as evidenced by X‐ray photoelectron spectroscopy and Raman spectroscopy, leads to the grafting of PE onto the nanotubes.     

A new bonding-tool solution to improve stitch bondability

A new bonding-tool solution is proposed to improve stitch bondability by creating a new surface morphology on the tip surface of a wire-bonding tool (capillary). The surface has relatively deep lines with no fixed directions. This new capillary has less slipping between the wire and the capillary tip surface and provides better coupling effect between them. Experiments of wire bonding on unstable lead frames/substrates, alloyed wire (2N gold wire) bonding, and copper wire bonding were carried out to confirm the effect of the new capillary on the stitch bondability. The experimental results are promising and have proved that the use of the new capillary could improve the bondability of the stitch bond and minimize the occurrence of short tail defects and non-sticking on lead during bonding.     

Silole‐Based Red Fluorescent Organic Dots for Bright Two‐Photon Fluorescence In vitro Cell and In vivo Blood Vessel Imaging

Robust luminescent dyes with efficient two‐photon fluorescence are highly desirable for biological imaging applications, but those suitable for organic dots fabrication are still rare because of aggregation‐caused quenching. In this work, a red fluorescent silole, 2,5‐bis[5‐(dimesitylboranyl)thiophen‐2‐yl]‐1‐methyl‐1,3,4‐triphenylsilole ((MesB)₂DTTPS), is synthesized and characterized. (MesB)₂DTTPS exhibits enhanced fluorescence efficiency in nanoaggregates, indicative of aggregation‐enhanced emission (AEE). The organic dots fabricated by encapsulating (MesB)₂DTTPS within lipid‐PEG show red fluorescence peaking at 598 nm and a high fluorescence quantum yield of 32%. Upon excitation at 820 nm, the dots show a large two‐photon absorption cross section of 3.43 × 10⁵ GM, which yields a two‐photon action cross section of 1.09 × 10⁵ GM. These (MesB)₂DTTPS dots show good biocompatibility and are successfully applied to one‐photon and two‐photon fluorescence imaging of MCF‐7 cells and two‐photon in vivo visualization of the blood vascular of mouse muscle in a high‐contrast and noninvasive manner. Moreover, the 3D blood vasculature located at the mouse ear skin with a depth of over 100 μm can also be visualized clearly, providing the spatiotemporal information about the whole blood vascular network.     

Effect of deicing solutions on the tensile strength of micro- or nano-modified asphalt mixture

This paper reports on the potential benefits of micro- or nano-sized materials for asphalt mixtures used on pavements, specifically when they are exposed to water or deicing solutions. Asphalt mixtures were prepared with various amount of nanoclay and/or carbon microfiber, and compacted using the Superpave? gyratory compactor. Moisture susceptibility and deicer impacts were assessed by exposing the samples to water or deicing chemicals (NaCl, MgCl₂ and CaCl₂), and seven freeze–thaw cycles, in a modified AASHTO T283 test. Comparisons of micro- or nano-modified asphalt mixtures exposed to deicers are made based on results of indirect tensile strength tests, which preliminarily demonstrate the great potential of using microfibers and nanoclays in asphalt mixture for improved performance. Based on the results, it was found that the addition of nanoclay and carbon microfiber would improve a mixture’s moisture susceptibility performance or decrease the moisture damage potential in most cases. The detailed effects of deicing solutions on the tensile strength of micro- or nano- modified asphalt mixture are discussed in this paper.