Ondansetron exhibits the properties of a local anesthetic

The purpose of this study was to determine whether ondansetron (OND) has local anesthetic effects. Using a patch-clamp technique, we showed that OND concentration dependently blocked Na channel currents in freshly isolated neurons of rat brains with a 50% inhibition concentration of 12 microM. The blockade started immediately when OND was applied to the cell body using a fast perfusion system, reached a plateau within 15 s, and recovered to the control level within 30 s after washout of the OND-containing solution. Because this is a known property of local anesthetics, we used the tail-flick technique to verify this effect in vivo in Sprague-Dawley rats (n = 46). OND was injected subcutaneously into the tail at the doses of 0.08, 0.16, and 0.2 mg. The tail-flick latency increased 2 min after OND injection, reaching the plateau within 5 min. This effect was dose-related, lasting from 10 to 25 min. These preliminary data indicate that OND, a selective 5-HT3 receptor antagonist, might serve as a prototype molecule for development of a novel series of local anesthetics. IMPLICATIONS: Ondansetron is a drug used to prevent vomiting, especially in cancer patients after chemotherapy. We found that it also causes numbness when injected under the skin. This new action may contribute to its role in "calming the stomach." We studied the effect of ondansetron on the isolated brain cells of live rats.     

A study of building a resource-based learning environment with the inquiry learning approach: Knowledge of family trees

This study aims to provide teachers with ways and means to facilitate learners to develop nomenclature knowledge of family trees through the establishment of resource-based learning environments (RBLEs). It discusses the design of an RBLE in the classroom by selecting an appropriate context with the assistance of computer-mediated learning resources and tools and employing the inquiry learning approach as the pedagogy. This study reports on the creation of the RBLE within the learning context of family trees. The computer-mediated learning resources and tools comprise three components: an audio-visual database for guided and coupled inquiry, an interactive interface for conceptualising the nomenclature and a tool for learners to construct their own family trees. Scaffolds were designed for an inquiry mode of learning and teaching to support the use of the resources and tools in learning about family trees. The learning and teaching process, including the outcomes for learners, through the RBLE with inquiry learning approach are studied. The findings of an interview and a pre-test/post-test study indicate that the RBLE can assist learners to build knowledge of family trees. The role of teachers in such an environment is to guide and encourage learners to inquire during the learning process.     

Energy impact assessment for the reduction of carbon dioxide and formaldehyde exposure risk in air-conditioned offices

Treatment of fresh air in ventilation systems for air-conditioning consumes a considerable amount of energy and affects the indoor air quality (IAQ). In this study, energy impact on ventilation systems was examined against certain IAQ objectives for indoor formaldehyde exposure risk in air-conditioned offices of Hong Kong. Thermal energy consumptions for ventilation systems and indoor formaldehyde exposure concentrations based on some regional surveys of typical offices in Hong Kong were reviewed. The thermal energy consumptions of ventilation systems operating for CO₂ exposure concentrations between 800 ppmv and 1200 ppmv for typical office buildings and the corresponding formaldehyde exposure risks were evaluated. The results showed that, for a reference indoor environment at a CO₂ exposure concentration of 1000 ppmv, the average thermal energy saving of ventilation system for a unit increment of the acceptable formaldehyde exposure limit of 1 h (loss of life expectancy of 0.0417 day) was 280 MJ m⁻² yr⁻¹; and for a unit decrement of the exposure limit of 1 h, an additional average thermal energy consumption of 480 MJ m⁻² yr⁻¹ was expected. This study would be a useful source of reference in evaluation of the energy performance of ventilation strategies in air-conditioned offices at a quantified exposure risk of formaldehyde.     

Corrosion Behavior of Sn-3.0Ag-0.5Cu Lead-Free Solder in Potassium Hydroxide Electrolyte

The corrosion behavior of Sn-3.0Ag-0.5Cu (SAC305) solder alloy in 6?M potassium hydroxide electrolyte was investigated using polarization analysis. The results revealed that SAC305 is susceptible to corrosion because of the dissolution of the Sn phase. The corrosion potential (E _corr) and corrosion current density (i _corr) obtained from the sample was ?C1.108?V vs Hg/HgO and 1.795?×?10^?4?A cm^?2, respectively. In addition, microstructural and elemental characterization revealed the presence of tin oxide, Cu, and/or Ag-containing corrosion product on the surface of the corroded sample. The morphology of the samples was also observed to contain several pits, cracks, and pore-like structures.     

Meaning representation in video outcomes of inquiry project

As student assignments and assessment evolve to keep pace with the technological developments, students have the opportunity to express their knowledge in a wider range of forms. The current study aims to examine the meaning representation in videos produced by secondary school students as part of a non-written inquiry project. The content of the video outcomes in the inquiry project, student interviews, and reflection essays written by the six participating students who were of different academic achievement levels were analyzed to better understand their meaning representation using videos. Five types of literacies used by the students in their video outcomes for meaning representation were identified: text, action, narration, cinematography and acoustics. The findings also showed that there were three types of meaning representations with different characteristics: drama, documentary and photo story. The components identified to be required for meaning representation in video were attitude towards video representation, choice of inquiry topic, organizational skills, and data management. The findings informed us of the possibility of diversified use of literacies for meaning representation in different genres of videos. The findings also alerted us of the need to equip students with necessary attitude and skills for better meaning representation. Nevertheless, the need to support learners to present meanings well with videos is suggested.     

Understanding the interplay of weak forces in [3,3]-sigmatropic rearrangement for stereospecific synthesis of diamines

Chiral diamines are important building blocks for constructing stereoselective catalysts, including transition metal based catalysts and organocatalysts that facilitate oxidation, reduction, hydrolysis, and C-C bond forming reactions. These molecules are also critical components in the synthesis of drugs, including antiviral agents such as Tamiflu and Relenza and anticancer agents such as oxaliplatin and nutlin-3. The diaza-Cope rearrangement reaction provides one of the most versatile methods for rapidly generating a wide variety of chiral diamines stereospecifically and under mild conditions. Weak forces such as hydrogen bonding, electronic, steric, oxyanionic, and conjugation effects can drive this equilibrium process to completion. In this Account, we examine the effect of these individual weak forces on the value of the equilibrium constant for the diaza-Cope rearrangement reaction using both computational and experimental methods. The availability of a wide variety of aldehydes and diamines allows for the facile synthesis of the diimines needed to study the weak forces. Furthermore, because the reaction generally takes place cleanly at ambient temperature, we can easily measure equilibrium constants for rearrangement of the diimines. We use the Hammett equation to further examine the electronic and oxyanionic effects. In addition, computations and experiments provide us with new insights into the origin and extent of stereospecificity for this rearrangement reaction. The diaza-Cope rearrangement, with its unusual interplay between weak forces and the equilibrium constant of the reaction, provides a rare opportunity to study the effects of the fundamental weak forces on a chemical reaction. Among these many weak forces that affect the diaza-Cope rearrangement, the anion effect is the strongest (10.9 kcal/mol) followed by the resonance-assisted hydrogen-bond effect (7.1 kcal/mol), the steric effect (5.7 kcal/mol), the conjugation effect (5.5 kcal/mol), and the electronic effect (3.2 kcal/mol). Based on both computation and experimental data, the effects of these weak forces are additive. Understanding the interplay of the weak forces in the [3,3]-sigmatropic reaction is interesting in its own right and also provides valuable insights for the synthesis of chiral diamine based drugs and catalysts in excellent yield and enantiopurity.     

Dystomatosis produced by fasciola hepatica: three cases in Madrid

Three cases of hepatic fascioliasis diagnosed in the Department of Internal Medicine are presented. All of the patients live in Madrid, all were fed watercress in the last month and the diagnosis was established during the invasive phase and confirmed by serological testing. We emphasized the importance of the TC scan in the correct diagnosis, the ectopic location of the parasite presentation like subcutaneous thoracic nodule and the efficacy of bithionol in the treatment.     

Line-profile and critical-dimension monitoring using a normal incidence optical CD metrology

As lithographic technology drives the minimum integrated circuit feature size toward 0.1 /spl mu/m and below, process tolerances for critical-dimension profile excursion are becoming increasingly demanding. In response, optical critical dimension metrology (OCD), an optical-wavelength light-diffraction technique, is emerging as a fast, accurate, and nondestructive sub-100-nm linewidth and profile monitor. As such, a detailed understanding of the correlation between OCD and existing metrology tools is required. Correlation between CD measurements using OCD and CD-scanning electron microscopy (SEM) techniques is investigated by measuring two types of important structures, e.g., photoresist gratings on a polysilicon gate film stack and shallow trench isolation. Intragrating CD variation is shown to account for scatter in the correlation plot. A qualitative line-profile correlation between cross-section SEM (X-SEM) and OCD is presented for photoresist gratings in a focus exposure matrix. Finally, a summary of the capability of OCD as a monitor for various processing stages is presented.     

Large‐Area,Periodic, Hexagonal Wrinkles on Nanocrystalline Graphitic Film

Sinusoidal wrinkles develop in compressively stressed film as a means to release stored elastic energy. Here, a simple way to fabricate large‐area, periodic, hexagonal wrinkled pattern on nanocrystalline graphitic films grown on c‐plane sapphire (<50 nm thick) by the spontaneous delamination–buckling of the as‐grown film during cooling is reported. According to the continuum mechanics calculation, strain‐relief pattern adopting the hexagonal wrinkled pattern has a lower elastic energy than that of the telephone cord wrinkle at thickness regime below 50 nm. A high‐fidelity transfer method is developed to transfer the hexagonal wrinkled films onto arbitrary substrates. Nanoindentation studies show that hexagonal wrinkle film engineered this way may act as shock absorber. The hexagonal wrinkled carbon film is able to selectively promote the differentiation of human mesenchymal stem cell toward the osteogenic lineage in the absence of osteogenic inducing medium.     

Fluid flows in microchannels with cavities

Pressure-driven gas and liquid flows through microchannels with cavities have been studied using both experimental measurements and numerical computations. Several microchannels with cavities varying in shape, number and dimensions have been fabricated. One set of microdevices, integrated with sensors on a silicon wafer, is used for flow rate and pressure distribution measurements in gas flows. Another set of microdevices, fabricated using glass-to-silicon wafer bonding, is utilized for visualization of liquid flow patterns. The cavity effect on the flow in the microchannel is found to be very small, with the mass flow rate increasing slightly with increasing number of cavities. The flow pattern in the cavity depends on two control parameters; it is fully attached only if both the reduced Reynolds number and the cavity number are small. A flow regime map has been constructed, where the critical values for the transition from attached to separated flow are determined. The numerical computations reveal another control parameter, the cavity aspect ratio. The flow in the cavity is similar only if all three control parameters are the same. Finally, the vorticity distribution and related circulation in the cavity are analyzed. [1546].