Search Results - (Author, Cooperation:K. C. Wong)

2018-03-29

BMJ Publishing

2044-6055

Medicine

Open access, Complementary medicine

2018-01-19

BMJ Publishing Group

Medicine

Stroke

2015-02-25

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Adolescent ; Adult ; Asthma/blood/genetics ; Child ; CpG Islands/genetics ; DNA Methylation/*genetics ; Eosinophils/cytology/metabolism ; Epigenesis, Genetic/*genetics ; Female ; *Genetic Association Studies ; Genome, Human/*genetics ; Humans ; Immunoglobulin E/*blood ; Inflammation Mediators ; Male ; Middle Aged ; Mitochondrial Proteins/genetics ; Pedigree ; Polymorphism, Single Nucleotide/genetics ; Transcription Factors/genetics ; Young Adult

2015-09-10

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Alleles ; Alternative Splicing/genetics ; Arecaceae/*genetics/metabolism ; *DNA Methylation ; Epigenesis, Genetic/*genetics ; *Epigenomics ; Fruit/genetics ; Genes, Homeobox/genetics ; Genetic Association Studies ; Genome, Plant/*genetics ; Introns/genetics ; Molecular Sequence Data ; *Phenotype ; Plant Oils/analysis/metabolism ; RNA Splice Sites/genetics ; RNA, Small Interfering/genetics ; Retroelements/*genetics

article

2008

Fallstudie ; Immobilie ; Wirtschaft ; Studium ; Auszeichnung ; Erfolgsfaktor ; Hongkong

Journal of real estate practice and education, Bd. 11 (2008) H. 2, S. 145-158, 1521-4842

English

1089-7550

AIP Digital Archive

Physics

Using an atomic force microscope, we studied various InAs-on-AlSb interface structures grown by molecular beam epitaxy. We found marked differences between the effects of the two interface bond configurations—InSb-like and AlAs-like—on the morphology of the subsequent InAs layer. In general, InSb-like interfaces lead to a much smoother InAs overgrown layer with clearly resolvable monolayer terraces. AlAs-like interfaces, on the other hand, lead to increasingly rougher InAs growth with longer As exposure. Previous studies have demonstrated a strong correlation between the interface configuration and the electron mobility in the InAs quantum well. The morphology and transport results we obtained indicate one reason for the influence of the interface configuration—a rough InAs layer. © 1997 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We report the growth of GaSb/AlSb serpentine superlattices (SSLs) on vicinal GaAs and GaSb substrates. Cross-sectional transmission electron microscopy confirms the SSL structure and shows excellent lateral uniformity, better than previous arsenide-SSLs. Photoluminescence (PL) measurements indicate a good-quality lateral superlattice with a spectral linewidth between 13 and 15 meV. Polarization-dependent PL measurements give a normalized linear polarization around 60%, the strongest that has been seen for SSL structures. Preliminary estimates suggest much better segregation between the Ga-rich and Al-rich regions than arsenide-SSLs, with the change in aluminum concentration Δx≈0.35.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

The growth of modulation-doped InAs/(Al,Ga)Sb quantum wells on GaAs substrates employing molecular beam epitaxy requires care in the nucleation and the use of buffer layers to achieve high quality material. Despite a 7% lattice mismatch between the substrate and the active layers, fully relaxed epitaxial growth can be accomplished, and quantum wells with electron sheet concentrations of 7×1012 cm−2 having low-temperature mobilities as high as 300 000 cm2/V s have been routinely fabricated recently in our laboratory. In the present work the combination of atomic force microscopy and van der Pauw measurements is used to investigate and explain the strong influence of the buffer layers on the morphology in the quantum well that is shown to be responsible for the great differences in the observed low-temperature mobilities. © 1996 American Institute of Physics.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The roles of the autonomic nervous system and cardiac output on hypoxic pulmonary vasoconstriction were studied in 15 mongrel dogs anaesthetised with intravenous pentoharbitone (30 mg/kg) and the lungs mechanically ventilated to maintain normal arterial blood gases. After a hypoxic challenge in Group I (n =6) and Group II (n =3) animals, autonomic denervation was achieved by total spinal block with tetracaine (20 mg) injected into the cisterna magna. Group I animals received a large volume of intravenous fluid (80 ml/kg normal saline) before the block while Group II animals were given minimum fluid. When Group I animals were exposed to 10% inspired oxygen, mean pulmonary arterial pressure increased by 88 and by 72% before and after the block, respectively. The cardiac output increased by 27% with hypoxia before the block while it did not change significantly with hypoxia after the block. The pulmonary vascular resistance increased by 65 and by 152% with hypoxia before and after the block. Group II animals were also exposed to 10% inspired oxygen. They showed a similar response to Group I animals before the block. However, after the block irreversible hypotension developed with hypoxia. In Group III animals (n =6), the same anaesthesia and hypoxic challenge protocol was used. Immediately after measurements at 10 minutes of hypoxia, the inferior vena cava was constricted to reduce the cardiac output to the control level and another set of measurements were made. The cardiac output increased by 30% with hypoxia and then was reduced to the control level with vena caval constriction. The mean pulmonary arterial pressure increased by 125% with hypoxia and then it decreased slightly with the inferior vena cava constriction. The pulmonary vascular resistance increased by 95% with hypoxia and then it further increased by 28% with the vena caval constriction. These results suggest that sympathectomy accentuates rather than attenuates the hypoxic pulmonary vasoconstriction and that an increase in cardiac output counteracts hypoxic pulmonary vasoconstriction. The results also suggest that adequate intravascular volume and oxygenation are extremely important for maintaining homeostasis when reflex sympathetic stimulation to the cardiovascular system has been eliminated.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We have proposed an equation for estimating the real-time mixed venous blood concentration (MVBC) of isoflurane in cardiac anaesthesia. However, information related to the application of our method to sevoflurane is lacking. We studied 12 patients undergoing cardiac surgery and anaesthetised with sevoflurane. At different time points, pulmonary arterial blood samples were collected for gas chromatography-mass spectrometry (GC-MS) to determine the real mixed venous concentrations of sevoflurane. The inspired and expired concentrations of sevoflurane, measured by a gas monitor, were used for the MVBC calculations. Using Bland-Altman analyses, we found that the calculated MVBCs accurately represent the actual concentrations of sevoflurane in pulmonary arterial blood, as shown by a near-zero percentage bias with a 0.14% precision between the two concentrations. The results demonstrated that our equation could be a useful method for estimating the pulmonary blood concentration of sevoflurane.

Electronic Resource

1365-2559

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

A male infant was diagnosed as having diabetes mellitus 1d after birth and died on the third day. Histological examination of the pancreas showed small and inconspicuous islets of Langerhans that were completely devoid of insulin-secreting cells. There was no evidence of insulitis.

Electronic Resource

1460-9568

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

During development motoneurons depend on target contact for their survival. Following injury to the sciatic nerve in neonatal rats, a large proportion of motoneurons die. However, the same injury inflicted at 5 days of age results in no loss of motoneurons. This critical period of postnatal development coincides with the time during which there is a significant increase in the release of transmitter from the nerve terminals at the neuromuscular junction. We have proposed that the role of the target muscle cell during this period is to induce this up-regulation of transmitter release from motor nerve terminals. It has been shown that stretch-induced increase in transmitter release from frog motor nerve terminals is accomplished via an integrin-dependent mechanism. In this study we examined the role of integrins at the rat neuromuscular junction in motoneuron survival. We found that blocking integrin binding at the developing neuromuscular junction delayed the increase in choline acetyltransferase activity that normally takes place during the early postnatal period, and resulted in motoneuron death. Furthermore, the maturation of those motoneurons that survived was delayed so they remained susceptible to subsequent nerve injury. These results support the possibility that integrins, by their involvement in modulating transmitter release, can influence motoneuron survival.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

In characterising the forces exerted during laryngoscopy it is accepted that the significant force component is that which is parallel to the axis of the laryngoscope handle. This paper describes a new method of evaluating the forces exerted at laryngoscopy. A laryngoscope handle has been redesigned, incorporating a force-displacement transducer on the handle at the end opposite to where the blade is attached. The device is designed specifically to sense the axial component of force. The blade attachment block has been detached from the sleeve and connected to a steel shaft which forms the new battery compartment. This allows the axial force exerted at the blade during laryngoscopy to be transmitted along this shaft to the sensing transducer. Linear ball bearings have been introduced between the new shaft and the handle sleeve (outer casing). The rolling friction has been reduced to less than 0.1 % by diamond-lapping the precision ground surface -hardened rod to produce a mirror finish. Thus, the force transmitted to the transducer is essentially constant regardless of where the load is applied along the blade. The output from the system is directly downloaded to a laptop computer and the data analysed almost instantaneously to determine the duration of laryngoscopy, the peak forces applied, the mean force with its standard deviation and graphic display of the data. Provision has been made for data entry checks, recording patient details and study data, and creating a data base for the storage and retrieval of the study details.

Electronic Resource

1432-2145

Averrhoa carambola ; Self-incompatibility Heterostyly ; Fluorescence microscopy ; Scanning electron microscopy ; Pollen tube ; Polymorphism

Springer Online Journal Archives 1860-2000

Biology

Abstract Various combinations of intermorph, selfing and intramorph pollinations were carried out in Averrhoa carambola and the pollinated pistils were observed under fluorescence and scanning electron microscopes in time-course experiments. In both compatible and incompatible pollinations, similar behavior of pollen germination and penetration was observed in the first 4 h after pollination. In compatible intermorph pollination, pollen tubes were found at the base of the transmitting tract of the style at 8 h and 24 h after pollination in both the pin and thrum morphs. With thrum flowers, selfing resulted in pollen tubes being uniformly arrested at the junction between the stigmatic and stylar tissues. Penetration of pollen tubes into the upper portion of style was observed in thrum intramorph pollination and, when the second member was treated as the gynoecial tissue under the same pollination, penetration of tubes was further enhanced. Pin flowers, on selfing, resulted in pollen tube penetration farther down the style than was the case with thrum selfing. Intramorph pollination of pin morph behaved in a similar manner to selfing and was not affected by genotypes. Beside the stamen-style dimorphism, the receptive surface of the cob stigma was larger in pin than thrum flowers. While pin pollen was round, thrum pollen was oblong in shape with pin to thrum ratio on the polar axis being 1.2 and on the equatorial axis 0.8. The stigma of pin morph belonged to the dry type, while that of the thrum resembled the wet type.

Electronic Resource

1432-2145

Averrhoa carambola ; Heterostyly Flower organ-specific proteins ; Electrophoresis Carambola/star-fruit

Springer Online Journal Archives 1860-2000

Biology

Abstract Floral organs (tepal, stamen, style, including stigma, and ovary) from immature and mature (1 day prior to anthesis) flower buds of pin and thrum morphs of Averrhoa carambola were subjected to one and two-dimensional IEF/SDS-PAGE gel electrophoresis and visualized by silver staining. One-dimensional gel electrophoresis of organ extracts from mature floral buds showed a number of protein bands common to all organs in both pin and thrum morphs. In the stamen and style, these bands differed in intensity between the two morphs. Under two-dimensional gels, the differences in protein profiles between the two morphs were more distinct in these organs. When compared with polypeptide spots from leaflets, a total of 14 floral organ-specific polypeptides was detected, the majority appearing in the stamen, followed by the style but none in the ovary. In the stamen, most of these polypeptides were detected in both the pin and thrum morphs. However, in the style, a 72-kDa polypeptide was detected exclusively in the pin morph, and this was also the most abundant floral organ-specific polypeptide. Floral organ-specific polypeptides of 45 kDa (detected in stamens of the thrum morph) and 70 kDa (detected in stamen and style of both morphs) were found to bind concanavalin A.

Electronic Resource

1573-7594

timed discrete-event systems ; time control structures ; hierarchical consistency

Springer Online Journal Archives 1860-2000

Mathematics

Abstract An abstract hierarchical control theory is developed for a class of timed discrete-event systems (TDES) within the discrete-event control architectural framework proposed earlier by the authors. For this development, a control theory for TDES is introduced in the spirit of a prior theory of Brandin. A notion of time control structures is introduced, and on its basis a general property of hierarchical consistency is achieved by establishing control consistency — namely preservation of time control structures through the aggregation mapping in a two-level hierarchy.

Electronic Resource

1573-7594

hierarchical control ; control structures ; observers ; hierarchical consistency

Springer Online Journal Archives 1860-2000

Mathematics

Abstract An abstract hierarchical control theory is developed for discrete-event systems, based on the concepts of control structures and observers. Control structure is an abstract generalization of the family of controllable sublanguages in the Ramadge-Wonham framework. We establish a general version of Zhong's hierarchical consistency by first achieving control consistency — preservation of control structures through the aggregation mapping in a two-level hierarchy. For a refinement of hierarchical consistency with preservation of nonblocking, the concept of observer is introduced via congruences on nondeterministic transition structures.

Electronic Resource