218 research outputs found
Surrendering the environment for capital gain and Olson's group theory: A case study of the dissolution of housing co-operative societies in Hong Kong
This paper describes the rise of the co-operative housing of civil servants and its fall during the transition of Hong Kong from a British colony to a special administrative region of the People's Republic of China. Olson's group theory was adopted to explain the timing of the dissolution in a context of uncertainty in the property rights of land; the terms of civil service appointments; and the housing market. The size of the ownership body and the value of the land were evaluated as factors affecting dissolution decisions. It was found that in agreement with Olson's theory, the number of members of the body had a statistically significant positive relationship with the life (between formation and dissolution) of the co-operative body. In addition, it was also found that factors that affected the opportunity cost of maintaining status quo, including the value of the land on which the co-op scheme sits and the real option value of redevelopment, had a significant impact on the timing of the dissolution of the co-op. The implications for using Olson's theory were also discussed. © 2011 Elsevier Ltd.postprin
Optimization of polystyrene-supported triphenylphosphine catalysts for aza-Morita–Baylis–Hillman reactions
A series of polar group functionalized polystyrene-supported phosphine reagents were examined as catalysts in the aza-Morita–Baylis–Hillman reactions of N-tosyl arylimines and a variety of Michael acceptors with the aim of identifying the optimal polymer/solvent combination. For these reactions JandaJel-PPh3 (1 mmol PPh3/g loading) resin containing methoxy groups (JJ-OMe-PPh3) on the polystyrene backbone in THF solvent provided the highest yield of all the catalyst/solvent combinations examined. The methyl ether groups were incorporated into JJ-OMe-PPh3 using commercially available 4-methoxystyrene, and thus such polar polystyrene resins are easily accessible and should find utility as nucleophilic catalyst supports.postprin
Sentinel lymph node biopsy based on anatomical landmarks and locoregional mapping of inguinofemoral sentinel lymph nodes in women with vulval cancer:an operative technique
Inguinal lymph node involvement is the most robust predictor of mortality in vulval cancer and sentinel lymph node (SLN) biopsy is a safe diagnostic modality. We describe a technique based on anatomical landmarks. Our aims are (1) to describe the territorial mapping of SLNs, (2) to evaluate the associated complication rate vis-à -vis those reported in the literature, and (3) to assess its accuracy in detecting SLNs. Data from women who underwent groin SLN biopsies for vulval cancer at a single cancer centre were prospectively collected. All subjects met the GROINSS-V eligibility criteria. The location of the SLN relative to the saphenous vein was recorded. All women were followed up and early and late complications were recorded. The recurrence rate at the time of the census was calculated. A total of 71 groins in 44 women were included. The SLN was primarily located over Cloquet’s node (85.2%). The incidence of early wound cellulitis and dehiscence were 2.8% and 11.3% while lymphocysts were present in 11.3% of groins. The negative nodal recurrence rate was 1.7%. Results showed that this reproducible technique allows access to 96.7% of SLNs, including both deep and superficial SLNs whilst minimising the need for extensive dissection and complications associated with overharvesting of lymph nodes
Histological regression of squamous esophageal carcinoma assessed by percentage of residual viable cells after neoadjuvant chemoradiation is an important prognostic factor
Background: Whether the TNM staging system is applicable after neoadjuvant chemoradiation in esophageal cancer is controversial. The aim of this study was to evaluate the prognostic value of histopathological regression of the primary tumor in postchemoradiated patients. Materials and Methods: The pretherapeutic and pathological ypTNM stages of patients who have had neoadjuvant chemoradiation followed by esophagectomy were analyzed. The percentage of residual viable cells of the primary tumor (ypV) and other clinicopathological factors were tested for their prognostic value. Results: Of 175 recruited patients, 55 (31.4%) achieved pathological complete response. The median survival of these 55 patients was significantly longer than those with other disease stages (124.8 vs 21.1 months) (P <.001). Gender, ypT, ypN, ypTNM, and ypV stage were significant prognostic factors in univariate analysis. In patients without nodal metastases, the median survival in patients with residual viable cells in the primary tumor (ypV?) was 24.6 months, compared with that of 124.8 months in those with no viable cells (ypV0) (P =.043). In those who had nodal metastases, the median survival of patients with ypV0 and ypV? were 21.2 months and 17.4 months respectively (P =.37). Cox regression analysis showed that male gender, high percentage of residual viable cells (ypV), and positive nodal status (ypN1) were independent predictors of poor prognosis. Conclusions: In patients who underwent neoadjuvant chemoradiation therapy, histopathological regression of the primary tumor indicated by percentage of residual viable cells is an important prognostic factor in addition to nodal status and gender. © The Author(s) 2010.published_or_final_versionSpringer Open Choice, 01 Dec 201
Fabrication of bulk heterojunction photovoltaic devices using sublimable rhenium diimine complexes as photosensitizers
A series of chlorotricarbonyl rhenium (I) bis(phenylimino)acenaphthene (Re-DIAN-X) complexes were used as the photosensitizers for photovoltaic cells. Unlike other transition-metal-based photovoltaic sensitizers that can only be prepared by solution method, these complexes are sublimable. Compared to other rhenium diimine complexes based on bipyridine or 1,4-diaza-1,3-butadiene ligands, these complexes have lower band gaps, which can be modified easily by changing the structure of the ligand. It allows the preparation of blend of metal complexes in order to broaden the sensitization region in UV-vis absorption spectrum. One of the complexes also shows bipolar charge transport character with relatively high charge carrier mobilities in the order of 10 -3 cm2V-1s-1. Multilayer heterojunction and bulk heterojunction devices with fullerene as the electron accepting molecule were prepared. For the bulk heterojunction devices, the fill factor and power conversion efficiency under AM 1.5 simulated solar light illumination were 0.51 and 1.29 %, respectively. The effects of changing the Re-DIAN/C60 film thickness, Re-DIAN/C60 ratio and variation of ligand structures in the bulk heterojunction devices were studied. The amount of photosensitizer and electron transport molecules may strongly affect the balance between the photon absorption, exciton formation, dissociation, and charge transport processes. Atomic force microscopic images showed that the complex dispersed evenly with fullerene molecules in solid state.published_or_final_versio
Fabrication of Photovoltaic Cell from Ruthenium Containing Polymer Using Layer by Layer Polyelectrolytes Adsorption Technique
Multilayer photovoltaic devices were fabricated by the sequence adsorption of different polyelectrolytes. A ruthenium terpyridine complex containing poly(p-phenylenevinylene) was used as the polycation layer. This polymer has been shown to exhibit large photo-sensitivity due to the presence of the ruthenium complex, which has relatively long-lived excited state. This polymer absorbs strongly in the visible region at ca. 480-550 nm and it can act as the electron transporter. Sulfonated polyaniline was used as the hole-transporting polyanion layer. The ITO/(polyanion/polycation) n/A1 devices were found to exhibit photovoltaic properties under the illumination of AM1 solar radiation. The short-circuit current I sc, open-circuit voltage V oc, and the fill factor FF were measured to be 14 ÎĽA/cm 2, 0.84 V and 0.16 respectively. It was found that the power conversion efficiencies of the devices were dependent on the device thickness. This simple layer-by-layer self-assembly method allowed us to control the devices thickness accurately.published_or_final_versio
Low-band-gap, sublimable rhenium(I) diimine complex for efficient bulk heterojunction photovoltaic devices
The fabrication of efficient bulk heterojunction photovoltaic cells using the chlorotricarbonyl rhenium(I) diimine complex as photosensitizer was discussed. The complex has a lower band gap, which can be adjusted easily by changing the structure of the ligand. The electric properties of the complex were studied using time-of-flight analysis. It was observed that the rhenium complex showed bipolar charge transport character with relatively high electron and hole mobilities.published_or_final_versio
Change of the emission spectra in organic light-emitting diodes by layer thickness modification
The electroluminescence (EL) and photoluminescence properties of organic light-emitting diodes (LED) were analyzed using layer thickness modification. Investigations show that the EL spectra exhibited significant variation with the increase of the viewing angle. It was found that multiple peak emission could be achieved for a certain range of thickness values. It was concluded that near white emission with CIE coordinates (0.32, 0.43) could be obtained for optimized device thickness.published_or_final_versio
miR-874-3p is down-regulated in hepatocellular carcinoma and negatively regulates PIN1 expression
published_or_final_versio
Absence of Detectable Influenza RNA Transmitted via Aerosol during Various Human Respiratory Activities – Experiments from Singapore and Hong Kong
Two independent studies by two separate research teams (from Hong Kong and Singapore) failed to detect any influenza RNA landing on, or inhaled by, a life-like, human manikin target, after exposure to naturally influenza-infected volunteers. For the Hong Kong experiments, 9 influenza-infected volunteers were recruited to breathe, talk/count and cough, from 0.1 m and 0.5 m distance, onto a mouth-breathing manikin. Aerosolised droplets exhaled from the volunteers and entering the manikin’s mouth were collected with PTFE filters and an aerosol sampler, in separate experiments. Virus detection was performed using an in-house influenza RNA reverse-transcription polymerase chain reaction (RT-PCR) assay. No influenza RNA was detected from any of the PTFE filters or air samples. For the Singapore experiments, 6 influenza-infected volunteers were asked to breathe (nasal/mouth breathing), talk (counting in English/second language), cough (from 1 m/0.1 m away) and laugh, onto a thermal, breathing manikin. The manikin’s face was swabbed at specific points (around both eyes, the nostrils and the mouth) before and after exposure to each of these respiratory activities, and was cleaned between each activity with medical grade alcohol swabs. Shadowgraph imaging was used to record the generation of these respiratory aerosols from the infected volunteers and their impact onto the target manikin. No influenza RNA was detected from any of these swabs with either team’s in-house diagnostic influenza assays. All the influenza-infected volunteers had diagnostic swabs taken at recruitment that confirmed influenza (A/H1, A/H3 or B) infection with high viral loads, ranging from 105-108 copies/mL (Hong Kong volunteers/assay) and 104–107 copies/mL influenza viral RNA (Singapore volunteers/assay). These findings suggest that influenza RNA may not be readily transmitted from naturally-infected human source to susceptible recipients via these natural respiratory activities, within these exposure time-frames. Various reasons are discussed in an attempt to explain these findings.published_or_final_versio
- …