Strong Pulling Research Articles

Charlie Loke: Contributions from Tennis Court Road—Past, Present and Future

0143–4004/03/$-see front matter and almost every volume of Trophoblast Research has contained his reviews. Yung Wai Loke (known to everyone as Charlie) was born in Penang, an island off the West Coast of Malaysia. His family fled to Singapore at the time of the Japanese invasion and he remembers the dog fights overhead before Singapore was captured in 1941. The remainder of the war was spent under the Japanese occupation in Kuala Lumpur living on a diet of brown rice. After the war he was despatched to England, a journey taking three days by air, and was educated at the Leys School and then King’s College in Cambridge. He then moved to St Thomas’s Hospital and qualified as a doctor in 1960 but, after spending a year as a houseman, he left England to return to Malaya where he worked as a Pathologist. It was there that his life was influenced in two important ways; he reduced his golf handicap to four and developed an interest in hydatidiform moles and choriocarcinomas, both common tumours in the Far East. There were strong pulls to settle permanently in Malaya and join the family business (his grandfather had emigrated from Southern China and founded the tin and rubber industries in Malaya), but in 1967 Charlie felt he should return to Cambridge. He was appointed as a Demonstrator in the Department of Pathology where he stayed for the next 35 years. In one of his earliest publications, arising from work performed in Malaya, he counted Barr bodies in placental tumours and found they were all XX in chromosome constitution and inferred (naively as it now turns out) that female placentae are more prone to the development of trophoblast tumours than males (Loke, 1969). Charlie’s long interest in trophoblast had begun. He became fascinated by how the allogeneic nature of choriocarcinomas might influence their behaviour (Loke, 1975) and the extension of this question to the normal placenta became his main intellectual preoccupation. Is the placenta discerned by the mother as self, nonself, missing self or surrogate self? How does this happen? Trophoblast cells are extraembryonic, arising from trophectoderm as the first differentiated cell of the embryo. The placenta is neither mother nor fetus, but provides an interface, a crucial intermediary, a no man’s land between these two genetically different individuals. There is an analogy with this concept in Charlie himself, buffered between England and Malaysia yet a To whom correspondence should be addressed at: Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK. Tel.: 44 1223 333727; Fax: 44 1223 765065; E-mail: am485@cam.ac.uk Figure 1. Charlie Loke, Melbourne, Australia, October 2002.

Instrumentation of STM and AFM combined with transmission electron microscope

A scanning tunneling microscope (STM) combined with a transmission electron microscope (TEM) is a powerful tool for direct investigation of structures, electronic properties, and interactions at the atomic scale. Here, we report on two different designs of such TEM-STM as well as an extension with an atomic force microscope (TEM-AFM). In the first TEM-STM design, a stepper motor, combined with a one-dimensional inertial slider, was used to perform the coarse approach. The advantage of this design was the strong pulling force that enabled notched metallic wires to be broken inside the TEM, which lead to clean sample surfaces. A second design, with a three-dimensional inertial slider, allowed lateral motion inside the TEM, which simplified the adjustment of tip location on the sample. By replacing the STM tip with a standard AFM-cantilever chip, a new combination was demonstrated: TEM-AFM. Here the force was simply measured by direct TEM imaging of the motion of the AFM tip. Some experimental results are included to illustrate the capabilities of TEM-STM and TEM-AFM.

Surface tension effects in the zero gravity inflow of a drop into a fluid

As a drop of fluid is deposited on the surface of a miscible fluid (that we call the solvent), it undergoes a strong pulling due to its surface rupture and it acquires a kinetic energy independently of gravity. For the drop and the solvent being of the same fluid we observe a drop injection at an initial velocity which scales as the square root of the surface tension of the drop against air. Once injected, the drop develops a transverse instability giving rise to an expanding ring. Viscosity terminates the process and stops the ring. We show that the final ring height follows a scaling law whereas two asymptotical scaling regimes can be identified for the ring radius.

Mechano-Synthesis of Niobium-Aluminum Superconductors for High Field Applications

In the present investigations, magneto-mechano synthesis, using a novel milling technique, was applied to mixtures of Al and Nb powders milled in Ar under different milling conditions. Structural development was monitoring using x-ray diffractometry, thermal analysis, and reflected light and electron microscopy. Powders milled using the ball impact method, and under shearing mode with a strong magnetic pulling force on the balls were observed to agglomerate due to cold welding. However, powders milled under shearing, with intermediate pulling force displayed continuous structural evolution, with Nb-Al solid solution occurring within 30 h of milling. With increased milling time there was a rapid decrease in Nb 3 Al lattice parameter, which reached a limiting value of 0.5185nm at around 250h milling. The DTA traces indicated an activation energy (Ea) of 377kJ/mol) for formation of Nb 3 Al, much higher than that reported for grain growth only, but close to that for the self-diffusion of pure elements, Al and Nb.

Hall effect in quasi-two-dimensional superlattices in nonquantizing magnetic and strong electric fields

The transverse electric field E y arising in quasi-two-dimensional superlattices (SLs) in a strong pulling electric field E x and a weak magnetic field oriented in a direction perpendicular to the plane of the SL (H ∥ Z) is calculated. In the case where the electronic energy spectrum is nonadditive, the field E y includes the Hall factor and the spontaneous transverse electric field that exists without H. The field E y is a multivalued and sign-variable function of E x . The asymptotically stable branches of the function E y are determined. The (kinetic) “potential,” whose minimum corresponds to a stationary state of the nonequilibrium electron gas, is used.

Social-psychological factors affecting language maintenance: Interviews with Shin Nisei university students in Hawaii

This article examines social-psychological factors affecting language maintenance by analyzing a group of second-generation heritage language learners' reflections on their networks of language contacts in childhood and adolescence. The focused group is American Shin Nisei (new second generation Japanese) university students in Hawaii. The data were collected through intensive interviews with six bilingual and semibilingual focal students and through extensive interviews with numerous other Shin Nisei university students. A statistical reference is also provided. Analysis indicates the strong assimilative pulls of the dominant culture even in multicultural/multiethnic Hawaii. In this sociocultural milieu, Japanese mothers play a critical role in Shin Niseis' Japanese language maintenance, especially oral skills, although a mother's choices cannot determine children's behavior; their language behavior interacts with social identity, which may change across time and space. This article also discusses problems facing educational institutions for Japanese language maintenance in Hawaii, such as the dominant use of English at heritage language schools and Shin Nisei students' socially frustrating and academically unsatisfactory learning experiences in formal foreign language classes.

Longitudinal–transverse mode interplay and conical emission in microchip lasers

Field confinement in a microchip laser with transversely varying gain and plane–plane cavity mirrors is theoretically discussed with a semiclassical treatment. We show that the common notion of a transverse cavity mode becomes closely linked to that of a longitudinal cavity mode owing to the key role that detuning of the longitudinal cavity frequency from the atomic resonance plays in the formation of the transverse field profile. In particular, we show that as the pump size decreases the laser emission is pulled toward the atomic resonance frequency on the negative detuning side. Strong mode pulling is interpreted as being due to the index-antiguiding effect induced by the pump and manifests itself as a ring pattern in the far-field spatial intensity.

Cross‐Pacific internationalization of R&D by U.S. and Japanese firms

AbstractEfforts by MNCs to develop coordinated international R&D networks have taken place from different historical bases of internationalization and in the context of differing trends in the role of R&D within the corporation, as the cross‐Pacific R&D investment in leading U.S. and Japanese firms in the electronics industry shows. Japanese firms, although they espouse a strategy of ‘localization’, are establishing wholly‐owned R&D centres in the U.S. with highly specialized technology mandates that to be used by the company must be networked with their parent organizations. U.S. firms rely on joint ventures or wholly‐owned labs with a wider array of technologies that face strong pulls to a local orientation. The patterns are somewhat out of line with the models of internationalization each side is espousing.

Cr migration associated with interface electric fields during transient LiNbO 3 crystal growth

The role of thermoelectric power and/or charge separation-generated electric fields upon Cr-doped LiNbO 3 crystal growth is treated by investigating both steady-state and initial transient solute redistribution based on the concept of a field-modified partition coefficient and an effective growth velocity. The magnitude of these electric field effects is dominated not only by the strength of the field but also by the solute diffusion coefficient in the phase considered. The high diffusion coefficient of Cr 3+ in the liquid and the very low diffusion coefficient of Cr 3+ in the solid combined with the electric field operating in the liquid leads to a strong pulling force on the Cr 3+ from the solid through the interface into the liquid. This generates a deep solute depletion region in the solid behind the interface. An analytical solution to this depletion phenomena is given for a specific case.

A simple pneumatic pulling mechanism for the production of micropipettes

An easily implemented scheme for the fabrication of glass micropipettes is described using a high‐velocity pneumatic piston for the production of a strong pulling force. The piston is incorporated into a standard two‐stage pipette puller and is capable of producing both patch‐ and ultramicro‐type pipettes. The system has the versatility of a solenoid puller with a greater simplicity and lower cost.

Phase locking laser diodes using photorefractive coupling

Several authors have reported strong frequency pulling while coupling laser diodes using phase conjugation. However, to our knowledge, no one has proven stable phase locking by interfering the laser outputs to show stable fringes. A stable phase lock has been obtained, and the geometry used is compared with those proposed previously.

Observation of strong frequency pulling in resonators employing multipass interferometric output couplers

The effect of dispersive elements, such as intracavity étalons and multipass interferometric output couplers, on the mode separation of a resonator has been studied. We demonstrate, both theoretically and experimentally in a TEA CO2 laser, that the separation of the two adjacent longitudinal modes closest to the interferometer reflection peak is strongly reduced when a high-finesse interferometer is used as an output coupler. This effect must be taken into account in the design of single-mode lasers.

Technique modification for radioactive implants when plastic tubes are used in fibrosed head and neck areas

Severe fibrosis around an area implanted with plastic tubes required a strong pulling tension force to place them in position. This pull produced a stretching of the tubes, and a consequent narrowing of the lumen, making afterloading with radioactive seeds impossible. Comments about this problem are made. Regular techniques in this situation cannot be used, and a technique modification is proposed.

Colonic displacement: Proposed treatment for gastric remnant volvulus due to eventration of the diaphragm

Displacement of the gastric remnant in patients with left diaphragmatic eventration may lead to gastric remnant volvulus requiring surgical correction. This results from the strong negative intrathoracic pulling force created by the potential subphrenic space and paradoxical movement of the diaphragm. Unless this strong negative force is first eliminated, gastropexy alone is likely to result in recurrence. Obliteration of the subphrenic space by colonic displacement is an effective and simple way of abolishing this negative subdiaphragmatic pulling force. Once this is achieved, any form of gastropexy will suffice to permanently prevent gastric remnant translocation and volvulus.

Voltage locking and other interactions in coupled superconducting weak links. II. Experiment

Experiments have been performed on two superconducting indium microbridges fabricated in close proximity (approx. =2 ..mu..m) to one another. The observed interactions include the following: (i) the apparent critical current of one bridge depends upon the current and voltage across the other bridge; (ii) gross modifications of the current-voltage characteristics of one bridge occur which are dependent on the current and voltage across the neighboring bridge; and (iii) strong voltage pulling is observed whenever the two bridge voltages are approximately equal, resulting in dc voltage locking under appropriate conditions. The ''voltage-locking'' interaction is of particular interest, and data are presented showing its observed temperature and frequency dependence. It is shown that the observed interactions are in qualitative agreement with a model based upon the diffusion of quasiparticles generated during the phase-slip process.

Interaction between pools of binocular disparity detectors tuned to different disparities.

Unambiguous dots (having one binocular disparity) when inserted in an ambiguous random-dot stereogram (with multiple disparity values) could pull the ambiguous percept. The unambiguous bias carried that ambiguous depth percept whose disparity was nearest to the disparity of the bias. The closer the disparities were to each other, the stronger the pulling effect that was observed. Even a physical bias of 4% density was adequate to overcome the natural bias of most observers. The stimulus duration had to be over 50 msec to provide a strong pulling effect. In all experiments the stimulus duration was 160 msec or shorter, indicating that the pulling effect was a product of neural interactions, rather than convergence movement of the eyes. As a result of these findings a parallel model of stereopsis has been proposed, which extends the spring-coupled dipole model of Julesz (1971).

On the Driving Forces of Plate Tectonics

Sumnznry We suppose that the plates are pulled along on top of an effectively viscous asthenosphere by their cold dense sinking leading edges, and that they also tend to slide down the flanks of ocean ridge systems. Using reasonable literature values of density, viscosity and thickness, we find that a typical strong subduction zone pulls about seven times as hard as a typical mid-ocean ridge pushes. With the simplifying assumptions that other driving forces are much smaller, and the return current in the asthenosphere is everywhere (anti)parallel to the plate velocity, we perform a torque balance for each major plate in order to find its angular velocity, thus finding a set of relative angular velocities to compare with observations. The directions fit quite well but not the magnitudes. On the additional hypothesis that oceanic lithosphere thickens with age, owing to heat diffusion, the driving forces will be greater for large old plates. The fit is thereby greatly improved: predicted speeds are from 0.81 to 1.38 times the observed and the COCOS plate is not anomalous. The model predicts tension in plates near their subduction zones. The Red Sea and African rift appear to have begun spreading as a crack moved into the former African +Arabian plate from a re-entrant corner off the Gulf of Aden which would have concentrated the stress. Gondwanaland may possibly have been split in a similar way.

Nuclear-Magnetic-Resonance Echo Enhancement in an Antiferromagnet

The observation of an anomalous enhancement of a two-pulse nuclear spin echo in antiferromagnetic MnO by a prepulse of variable width, amplitude, and delay time is described. A theory explaining this observation by adding frequency pulling to the Bloch equations is discussed. In this model the frequency pulling parameter is assumed to be inhomogeneous throughout the sample, consistent with current ideas of NMR line broadening in materials with strong pulling. Long free-induction decays observed following wide pulses are also explained.

アーク溶接現象に関する界面張力理論(第4章)

The author has proposed the following mechanism of penetration in Chapter 3 of this report.The contact line of a mother drop push-squeezed by the arc force recedes, leaving the base metal surface bare. Near the point where the contact line starts to deviate from the boundary line of the surface of penetration, a strong pulling force to counteract the arc pressure is developed and this is the greater, the larger the value of the angle of penetration θg. When the θg of exposed surface is increased through direct action of arc the exposed surface displaces itself, and a "Peripheral Penetration" is caused at the front portion of the surface of penetration through the joint action of arc and mother drop.The theory was testified in this report through the observation of various patterns of penetration and other evidences. Existence of bare surface of mother metal during welding proved to be true, and the traces of direct action of arc were discovered as small concavities upon it. Although the proposed theory is satisfactory for the peripheral penetration, it is necessary to modify the theory in order to explain the "Central Penetration", which is the result of direct action of arc on the constantly exposed base metal without interference of the mother drop. And at the rearward portion of the peripheral penetration, indirect action of the liquid metal overheated by arc plays a significant role, which is also coupled with the oscillation of the mother drop.It was concluded that the most essential factors to decide the type of penetration are arc force on the one side and interfacial tension and contact angle of the mother drop on the other, because the interaction of these forces determines the size of exposed bare surface and induces its oscillation around the surface of penetration.