GaSb(001) Surface Reconstructions Measured at the Growth Front by Surface X-ray Diffraction

Surface x-ray diffraction was employed, in situ, to measure the GaSb(001)-(1 × 5) and (1 × 3) surface phases under technologically relevant growth conditions. We measured a large set of fractional-order in-plane diffraction peaks arising from the superstructure of the surface reconstruction. From the data we calculated two-dimensional (2D) Patterson functions, the peaks of which represent inter-atomic distances weighted by the number of electrons in the individual atoms. For the (1 × 3) phase we obtained good agreement between our data and the β(4 × 3) model proposed in recent experimental and theoretical work. Our measurements on the Sb-rich (1× 5) phase provide evidence that the structure under growth conditions is, in fact, different from that of the models previously suggested on the basis of scanning tunneling microscopy (STM). We discuss reasons for this discrepancy as well as the identified structural elements for these reconstructions, which include surface relaxations and subsurface rearrangement.     

Comparison of ultrasonic wave transmission and reflection measurements with P- and S-waves on early age mortar and concrete

This paper reports on results of round robin tests comparing two nondestructive, ultrasonic techniques: the wave transmission method using P-waves and the wave reflection method using S-waves. The experiments were conducted within the activities of the RILEM Technical Committee TC ATC-185 with the objective to evaluate the ability of these methods to continuously monitor the setting and hardening process of cementitious materials. In total, eight different mortar and concrete mixtures were subjected to the ultrasonic tests. Additionally, experiments were conducted to determine the penetration resistance (ASTM C 403), the in-situ temperature rise, the adiabatic heat release, and the chemical shrinkage (of the cement paste phase) of the investigated materials. The results revealed that, originating from the different wave types, the two ultrasonic methods monitor the setting process of mortar and concrete in significantly different ways. Despite these differences, the comparison of the ultrasonic test results with the development of the adiabatic heat and the chemical shrinkage has proven that P-wave velocity and reflection loss, as the parameters measured by the two methods, have a consistent and direct relationship to the cement hydration process.     

Phospholipase C beta and membrane action of calcitriol and estradiol

We have shown that estrogens and calcitriol, the hormonally active form of vitamin D, increase the concentration of intracellular calcium ([Ca2+]i) within 5 s by mobilizing calcium from the endoplasmic reticulum and the formation of inositol 1,4, 5-trisphosphate and diacylglycerol. Because the activation of effectors as phospholipase C (PLC) coupled to G-proteins is the early event in the signal transduction pathway leading to the inositol 1,4,5-trisphosphate formation and to [Ca2+]i increase, we described different PLC isoforms (beta1, beta2, gamma1, and gamma2, but not beta4) in female rat osteoblasts using Western immunoblotting. The data showed that phospholipase C beta was involved in the mobilization of Ca2+ from the endoplasmic reticulum of Fura-2-loaded confluent osteoblasts by calcitriol and 17beta estradiol, and PLC gamma was ineffective. The data also showed that only a PLC beta1 linked to a Pertussis toxin-insensitive G-protein and a PLC beta2 coupled to a Pertussis toxin-sensitive G-protein are involved in the effects of calcitriol and 17beta estradiol on the mobilization of Ca2+ from intracellular Ca2+ stores. In conclusion, these results may be an important step toward understanding membrane effects of these steroids and may be an additional argument in favor of membrane receptors to steroid hormones.     

Comparison of micropatterning methods for ceramic surfaces

The fabrication of defined ceramic micropatterns smaller than 100 μm is due to the hardness and brittleness of ceramic materials still very challenging. However, in recent years, micropatterned ceramic surfaces have become highly interesting for biomedical applications or the fabrication of energy converting devices, such as solid oxide fuel or solar cells. In this study we evaluate six modern techniques for ceramic pattern fabrication with feature sizes ranging from 5 to 100 μm. Ceramic materials such as alumina, zirconia, silica and hydroxyapatite are discussed. Advantages and disadvantages for each process are highlighted and compared to the other techniques. Three of these techniques, namely microtransfer molding, modified micromolding and Aerosol-Jet^® printing generate patterns starting with aqueous ceramic suspensions. The other three techniques, micromachining and two different types of laser treatment produce micropatterns by material removal from solid ceramic substrates. The detailed analysis yields that properties such as the desired micropatterning size, shape or the production time are strongly dependant on the chosen technique.     

Fiber-Optic Photoacoustic Generator Realized by Inkjet-Printing of CNT-PDMS Composites on Fiber End Faces

In recent years, photoacoustic generators based on multiwalled carbon nanotubes (MWCNT) and polydimethylsiloxane (PDMS) are manufactured in a variety of ways, which influences the properties of the generators with respect to frequency bandwidth, sound wave pressure, robustness, and reproducibility. Due to the high optical absorption of MWCNTs and the high thermal expansion coefficient of PDMS, this combination is ideally suited for use as a photoacoustic generator. This study presents a novel method to produce photoacoustic generators based on long-term stable MWCNT and PDMS inks with a high reproducibility by means of inkjet-printing. The MWCNT-PDMS layers (thicknesses of 2–4 µm), printed directly onto the distal end face of a multimode glass fiber, show a good homogeneity and low optical transmission (19–21%). After the preparation of the fiber pieces, the inkjet printer performs all steps automatically in a time period of 30–60 s per layer. The generated ultrasonic pressure (0.39–0.54 MPa) and frequency bandwidth (1.5–12.7 MHz) can be measured at a distance of ≈4 mm with a laser fluency of 12.7 mJ cm⁻². These highly reproducible printed photoacoustic generators can be well used for nondestructive material testing and medical applications.     

The working alliance: Where are we and where should we go?

This article describes important findings that have emerged from decades of research on the working alliance, as well as some of the clinical implications of these findings. In addition, future directions of research on this construct are suggested. Our hope is that this article will provide useful heuristics for better understanding the alliance, the therapeutic relationship more broadly, and the process of therapeutic change in general. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Static and shock-tension loaded headed studs in reinforced concrete

By means of experimental investigations and theoretical approaches, methods were developed which take hold of the process of static and shock-tension loaded headed studs embedded in reinforced concrete. For the analysis of the failure mechanism, the test results available from the literature as well as own experiments were used. In particular, shock loads where tension builds up within milliseconds were considered. For both the static stress and the dynamic load-bearing capacity, design formulae could be developed by applying dimensional analysis. These design rules permit the determination of the most relevant variables which describe the failure mechanism.     

Controlling outcomes through impression-management: An experimental study of the manipulative tactics of mental patients.

An attempt to explore mental patient's attitudes toward staying or leaving the mental hospital, their use of impression management as a strategy to increase the probability of satisfying these desires, and the relationship between mental patient strategies and discharge rates. The study found that old-timers (who have the lowest discharge rate in the hospital) will attempt to present themselves on mental status tests as ill and ineligible for discharge while short-timers (who have the highest discharge rate in the hospital) will present themselves on mental status tests as healthy and eligible for discharge. The findings were presented as supporting the assumptions that mental patients are not necessarily helpless and ineffectual people and that they will try, in many ways, to determine their hospital fate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)