Synthesis and characterization of highly twisted and bulky tetraoctyloxybiphenyl-containing polyfluorene copolymers: toward efficient blue polymer light emitting diodes

We have synthesized new blue light emitting random copolymers, poly(9,9'-n-dioctylfluorene-co-2,2',6,6'-tetraoctyloxybiphenyl-3,3'-diyl)s (PFTOBPs), via Ni(0)-mediated coupling reactions. The PL emission peaks of the resulting copolymers closely resembled those of the polyfluorene (PF) homopolymer. The EL devices fabricated using these copolymers exhibited highly pure blue emission with approximate 1931 CIE coordinates of (0.15, 0.15) at 1000 cd/m2. The maximum brightnesses ranged from 2000 to 12000 cd/m2 with maximum efficiencies from 0.53 to 0.97 cd/A. The efficiencies were found to increase as the fraction of TOBP in the copolymers was increased, which may result the inhibition of exciton quenching that is produced by the introduction of the highly twisted and bulky TOBP moieties into the copolymers.

Quantitative investigation on the distribution of Malassezia species on healthy human skin in Korea

This study concerns a culture research based on the data gathered from Korean subjects to examine distribution of Malassezia yeast. Malassezia yeast were cultivated out of samples from scalp, forehead, chest, arm and thigh. Malassezia restricta was recovered more frequently in the teens and young adults, while M. globosa was the predominant species in subjects older than 50 years of age. The population density of Malassezia yeast was significantly higher in the age group (AG) of 21-30 years compared with other AGs (P < 0.05). It was also significantly higher in the chest compared with the forehead, arm and thigh (P < 0.05). The key is to recognise the existence of a difference in the amount and type of Malassezia species in different AGs as well as body areas, which reflects differing skin lipid levels in various AGs and different body areas.

SRF is a nuclear repressor of Smad3-mediated TGF-beta signaling

Serum response factor (SRF) is a widely expressed transcription factor involved in immediate-early and tissue-specific gene expression, cell proliferation and differentiation. We defined a new role of SRF as a nuclear repressor of the tumor growth factor beta1 (TGF-beta1) growth-inhibitory signal during cell proliferation. We show that SRF significantly inhibits the TGF-beta1/Smad-dependent transcription by associating with Smad3. SRF causes resistance to the TGF-beta1 cytostatic response by directly repressing the Smad transcriptional activity and Smad binding to DNA. Furthermore, we demonstrated that overexpression of SRF markedly decreases the level of Smad3 complex binding to the promoters of Smad3 target genes, p15(INK4b) and p21(Cip1). This leads to the inhibition of expression of TGF-beta1-responsive genes. SRF therefore acts as a nuclear repressor of Smad3-mediated TGF-beta1 signaling.

Genetic analysis of SCA2, 3 and 17 in idiopathic Parkinson's disease

Recent reports of SCA2 and SCA3 patients who presented with levodopa responsive parkinsonism have generated considerable interest as they have implications for genetic testing. It is unclear whether ethnic race alone or founder effects within certain geographical region explain such an association. In this study, we conducted genetic analysis of SCA2, 3, 17 in an ethnic Chinese cohort with early onset and familial Parkinson's disease (PD) and healthy controls. A total of 191 subjects comprising of 91 PD and 100 healthy controls were examined. We identified one positive case of SCA2 in an early-onset sporadic PD patient who had CAG 36 repeats, yielding a prevalence of 2.2% in early-onset sporadic PD patients and less than 1.0% in our study PD population. The size of the repeats was lower than the expanded repeats (38-57) in SCA2 patients with ataxia in our population. All the children of the patient were physically normal even though some of them carried the repeat expansion of similar size. No cases and controls were positive for SCA3 and SCA17. We do not think routine screening of SCA2, SCA3 and SCA17 for all idiopathic PD patients is cost-effective in our ethnic Chinese population. However, SCA2 should be a differential diagnosis in young onset sporadic PD when genetic mutations of other known PD genes have been excluded.

Paraplegia caused by spinal infection after acupuncture

STUDY DESIGN

Case report of a 64-year-old man with psoas abscesses, epidural abscess and spondylitis after acupuncture.

OBJECTIVE

To report a case of paraplegia caused by spinal infection after acupuncture.

SETTING

Seoul, Korea.

CASE REPORT

A 64-year-old man came to an emergency room because of severe back pain. At 3 days prior to visit, the patient received acupuncture therapy to the low back with a needle about 10 cm in length because of back pain. Pain was aggravated gradually for 3 days. Escherichia coli sepsis developed with altered mentality during admission. At hospital day 9, he regained his consciousness and was found to have paraplegia. Abdominal computerized tomography (CT) and lumbar spine magnetic resonance imaging (MRI) revealed abscesses of bilateral psoas muscles and spondylitis with epidural abscess. After conservative management with intravenous administration of antibiotics, infection was controlled but the patient remained paraplegic (ASIA scale C L1 level) without neurological recovery.

CONCLUSION

Paraplegia might result from complications of an acupuncture therapy.

Thermal Decomposition of Commercial Silicone Oil to Produce High Yield High Surface Area SiC Nanorods

This article reports on the synthesis of high surface area (563m2/g) beta-SiC nanorods by thermal decomposition of commercial silicone oil at a relatively low reaction temperature (800 degrees C) in a closed Swagelok cell. High yield (75%) of SiC nanorods are obtained in this one-stage, solvent-, catalyst-, and template-free synthesis technique that runs at a relative low temperature and employs cheap single-precursor. The morphological (TEM, HR-SEM), compositional (CHNS, EDX, SAEDX]), structural (XRD, HR-TEM, and ED), thermal (TGA) characterizations and surface area analysis are carried out for the obtained SiC nanorods. The possibility of hydrogen storage in this high surface area nano-SiC rods are also tested and reported for the first time.

Biological nutrient removal using an IACOD process: determining the combined effects of low temperature and long solids retention time

This study was undertaken using an intermittently aerated cylindrical oxidation ditch (IACOD) process for biological nutrient removal. The kinetic aspects of nitrification, denitrification, and phosphorus release/uptake were investigated by conducting a pilot-scale operation under various contact times for the aerobic/anoxic reactor, SRTs, and HRTs. The effects of temperature were also evaluated. The results of the study revealed that a cycle time of 180 min. (i.e., the aerobic contact time of 60 mim. followed by the anoxic contact time of 120 min.) enhanced the biological nutrient removal at an aerobic SRT of 8.3 days and an HRT of 24 hours in the aerobic/anoxic reactor. Even during the winter months with mixed liquor temperatures between 9.6 degrees C and 12 degrees C at an aerobic SRT of 10 days, the IACOD process was capable of almost completely nitrifying the influent NH4- -N. The IACOD process was also capable of denitrifying the NO3- -N in the aerobic/anoxic reactor, yielding effluent NO3- -N concentrations of less than 2.0 mg l(-1) N. Furthermore, the release and abundant uptake of phosphorus successfully occurred at this low temperature range. The enhanced biological phosphorus removal rates increased steadily as the temperature increased from 9.6 degrees C to 22 degrees C. However, an inhibition of phosphorus release was observed at a temperature range of 18 degrees C to 20 degrees C. This inhibition might have been caused by the sudden increase in the NO3- -N concentration of the return sludge, which was induced by the rapid nitrification of the influent NH4+ -N at a relatively elevated temperature. The inhibition was not prolonged due to the subsequent increase in the denitrification rate as the temperature increased further to 20 degrees C and above.

An acid phosphatase from Manihot glaziovii as an alternative to alkaline Phosphatase for molecular cloning experiments

An acid phosphatase, free of deoxyribonuclease activity, was isolated from Manihot glaziovii leaves. It had a Mr of 78 kDa and was optimally active at pH 4.3 and 52 degrees C. It was inactivated at 65 degrees C over 15 min. It had a broad substrate specificity with strongest activity towards p-nitrophenyl phosphate. The enzyme dephosphorylated linearized pUC18 DNA and preventing self-ligation under the same conditions used for calf intestine alkaline phosphatase.

Electrocardiographical case. ST elevation: is this an infarct? Pericarditis

A 25-year-old man presented at the emergency department with complaints of fever and chest pain. The electrocardiogram (ECG) showed concave ST segment elevation that was not confined to any arterial territory. There was PR segment elevation in lead aVR as well as PR segment depression in leads II, V5 and V6. This was consistent with pericarditis. The electrocardiographical changes associated with pericarditis are discussed. A second case of a 64-year-old man with uraemic pericarditis with similar ECG changes is illustrated.

Electrocardiographical case. A tale of tall T's. Hyperkalaemia

A 63-year-old woman presented at the emergency department (ED) with a history of increasing lethargy and drowsiness. The electrocardiogram (ECG) showed tall peaked T waves with broadening of the QRS interval, suggestive of hyperkalaemia. This patient had an elevated serum potassium level due to diabetic ketoacidosis. She was treated with intravenous calcium chloride and insulin with 50% dextrose. The ECG changes associated with hyperkalaemia are discussed, with illustrations from a second 48-year-old male patient with renal failure who presented with malaise, lethargy and generalised weakness.

Sensitization to dust mites in children with allergic rhinitis in Singapore: does it matter if you scratch while you sneeze?

BACKGROUND

Previously published data established Blomia tropicalis, as the major source of allergic sensitization in asthmatic children in tropical Singapore. Objective To define the prevalence, clinical characteristics and risk factors of species-specific mite sensitization in paediatric allergic rhinitis (AR) patients in this unique environment.

METHODS

We performed a prospective evaluation of newly diagnosed AR patients, from 1 May 2003 to 30 April 2004, from the otolaryngology and allergy outpatient clinics of the Kendang Kerbau Children's Hospital in Singapore. Patients included in the study showed evidence of sensitization to at least one respiratory allergen source and completed a detailed questionnaire. Relative risk of sensitization and associated risk factors were calculated using logistic regression analysis with the forward stepwise model. Multivariate regression analysis was performed to adjust for confounding interactions. Continuous values were compared using anova, SPSS 9.0 for Windows (SPSS Inc., 1999).

RESULTS

One hundred and seventy-five patients were included, 119 (68%) males, 142 (81%) Chinese, age mean 7.9 years (range 2-16). Sixty-eight patients (39%) reported a concomitant diagnosis and/or clinical complaints of bronchial asthma and 84 (48%) of atopic dermatitis. Skin prick test results were positive for traditional house dust mites (Dermatophagoides pteronyssinus. and D. farinae mix) in 85% of patients and for B. tropicalis in 62%. Overall mite sensitization was 98%, household pets 10%, moulds 9% and food proteins 12%. By far the single most significant factor associated with Dermatophagoides sensitization in this group was the presence of allergic eczema (odds ratio (OR) 31.8%, 95% confidence interval (CI) 3.6-285, P=0.002). Allergic eczema was negatively associated with B. tropicalis sensitization (OR 0.26%, 95% CI 0.14-0.5).

CONCLUSIONS

Children with AR and concomitant atopic dermatitis show a preferential sensitization to the Dermatophagoides mites. In our population, B. tropicalis sensitization is more prominent in children with pure respiratory allergy.

Highly ordered carbon nanotubes based on porous aluminum oxide: fabrication and mechanism

Highly ordered carbon nanotubes (CNTs) are wildly pursued due to their unique properties. Anodic aluminum oxide (AAO) exhibits great possibility for this purpose. Here, CNTs based on AAO template were produced using acetylene or ethylene as the hydrocarbon sources with or without the presence of Co catalysts. CNTs grown on the Co-embedded AAO samples were normally confined within the nanopores of the AAO template. It was found that C2H4 normally requires 100 degrees C higher pyrolysis temperature than C2H2 under otherwise identical conditions. The pyrolysis temperature is greatly reduced with the presence of Co catalysts. CNTs can grow out of the nanopores, if Co particles are present at the bottom of the nanopores and if the nanopores are short in length or large in diameter. The graphitization of AAO template grown CNTs was studied by Raman spectroscopy. The CNTs produced from ethylene are generally better in graphitization than those from acetylene, and the CNTs grown with the presence of Co catalysts deposited at the bottom of nanopores are better than those without Co catalysts or with Co catalysts coated on the entire inner wall of nanopores. The growth temperature is found not to play a critical role in graphitization.

Electrocardiographical case. Young man with generalised myalgia

A 24-year-old man presented with generalised malaise and myalgia for three days. He presented to the Emergency Department after a fall at his workplace due to weakness. 12-lead electrocardiogram (ECG) showed normal sinus rhythm with ST depression in the leads V4 to V6, with a U wave. The tallest U wave appeared in V3. These ECG features are characteristic of hypokalaemia. ECG changes in hypokalaemia and differential diagnosis are discussed. A second case of thyrotoxic periodic paralysis with similar ECG changes of hypokalaemia is also presented.

Sp17 gene expression in myeloma cells is regulated by promoter methylation

The mechanisms underlying sperm protein 17 (Sp17) gene expression in myeloma cells remained unclear. Using reverse transcription–polymerase chain reaction (RT–PCR), Sp17 transcripts were detected in ARK-B, ARP-1, RPMI-8226 and KMS-11 but not in H929, IM-9, MM1-R and U266 cells. Using a panel of primer pairs in methylation-sensitive PCR to amplify overlapping gene segments, our screening studies showed that the HpaII sites at −359 and −350 are involved in the regulation of Sp17 gene expression. To confirm the differences in methylation status between Sp17-positive and Sp17-negative cell lines, KMS-11 cells (Sp17-positive) and IM-9 cells (Sp17-negative) were subjected to the more accurate method of bisulphite conversion. KMS-11 cells were more hypomethylated at these HpaII sites of exon 1 compared to IM-9 cells, indicating the association of hypomethylated promoter with Sp17 gene expression. In addition, the level of methylation at other CpG sites within the promoter sequence was also higher in IM-9 than KMS-11. Exon 1 was cloned into a reporter vector, pCAT^*3 Enhancer. Chloramphenicol acetyl transferase (CAT) activity was restored in cells transfected with the recombinant plasmid, indicating the promoter function of exon 1. Exposure of Sp17-negative cell lines to the hypomethylating agent, 5-azacytidine, resulted in the upregulation of Sp17 gene expression. Our results therefore provide evidence for the regulation of Sp17 gene expression by promoter methylation.

Highly ordered carbon nanotubes based on porous aluminum oxide

Highly ordered carbon nanotubes (CNTs) are widely pursued due to their unique properties. Anodic aluminum oxide (AAO) exhibits great possibility for this purpose. Here, CNTs based on AAO templates were produced using acetylene or ethylene as the hydrocarbon sources with or without the presence of Co catalysts. CNTs grown on the Co-embedded AAO samples were normally confined within the nanopores of the AAO template. It was found that C2H4 normally requires 100 degrees C higher pyrolysis temperature than C2H2 under otherwise identical conditions. The pyrolysis temperature is greatly reduced with the presence of Co catalysts. CNTs can grow out of the nanopores if Co particles are present at the bottom of the nanopores, and if the nanopores are short in length or large in diameter. The graphitization of AAO-template grown CNTs was studied by Raman spectroscopy. CNTs produced from ethylene are generally better in graphitization than those from acetylene, and CNTs grown with the presence of Co catalysts deposited at the bottom of nanopores are better than those without Co catalysts or with Co catalysts coated on the entire inner wall of nanopores. The growth temperature is found not to play a critical role in graphitization.

Search for electron neutrino appearance in a 250 km long-baseline experiment

We present a search for electron neutrino appearance from accelerator-produced muon neutrinos in the K2K long-baseline neutrino experiment. One candidate event is found in the data corresponding to an exposure of 4.8 x 10(19) protons on target. The expected background in the absence of neutrino oscillations is estimated to be 2.4+/-0.6 events and is dominated by misidentification of events from neutral current pi(0) production. We exclude the nu(micro) to nu(e) oscillations at 90% C.L. for the effective mixing angle in the 2-flavor approximation of sin((2)2theta(microe)( approximately 1/2sin((2)2theta(13))>0.15 at Deltam(2)(microe)=2.8 x 10(-3) eV(2), the best-fit value of the nu(micro) disappearance analysis in K2K. The most stringent limit of sin((2)2theta(microe)<0.09 is obtained at Deltam(2)(microe)=6 x 10(-3) eV(2).

Varicella screening and vaccination for healthcare workers at KK Women's and Children's Hospital

INTRODUCTION

Varicella is a highly contagious disease with significant morbidity and mortality, especially in adults. It can lead to nosocomial transmission with dire consequences, especially in a healthcare facility where children and pregnant women form the majority of patients. At KK Women's and Children's Hospital, we embarked on a programme in 2 phases, between 1997 and 1999, to screen healthcare workers (HCWs) for varicella immunity and to offer varicella vaccination to those who tested negative for antibody.

MATERIALS AND METHODS

HCWs were initially screened via a questionnaire; those with no previous history of chickenpox underwent a blood test for varicella zoster antibody. Varicella vaccine was offered to those who tested negative for antibody and they were monitored for adverse reactions.

RESULTS

Of the HCWs surveyed, 14.7% and 26.9% in phases 1 and 2, respectively, had no previous history of chickenpox. Of these, 55.3% in phase 1 and 26.1% in phase 2 tested negative for antibodies. Thus, the overall seronegativity of all HCWs surveyed was between 6.5% and 7.6%. Among those who tested negative for antibodies, 42.9% in phase 1 and 74% in phase 2 were vaccinated. Hence, the overall vaccination rate in HCWs was 3.2% and 4.8% in phases 1 and 2, respectively. Adverse reactions were observed in 2 (22.2%) HCWs in phase 1 and in 9 (9.3%) in phase 2, consisting mostly of maculopapular rashes or vesicles around the injection site.

CONCLUSIONS

Our study shows that 26% to 55% of HCWs with no history of chickenpox and who tested negative for antibody against varicella required vaccination. Hence, in healthcare facilities, varicella screening and vaccination should be offered to all HCWs.

Traumatic atypical Brown-Sequard syndrome: case report and literature review

A man was kicked on the neck, 10 days after which he noted right-sided numbness. Clinically, he had diminished deep tendon reflexes over the left upper limb, absent left superficial abdominal reflexes, a left extensor plantar response, mild left hemiparesis, diminished pinprick, temperature and vibratory sensation up to the right T(4-5) dermatome and diminished proprioceptive sensation in the right upper and lower limbs. Cervicothoracic magnetic resonance imaging (MRI) revealed a left C(6-7) posterolateral disc prolapse with indentation and oedema of the cord at the same level. He was given intravenous dexamethasone, with mild resolution of his motor but not his sensory symptoms. Transcranial magnetic stimulation and evoked potentials performed 3 days later were unremarkable. He was discharged soon after, preferring to seek traditional therapy in his country. We attempt to explain the anatomical basis for his clinical signs, review the literature for similar cases, and examine the usefulness of available treatment and investigations.

Indications of neutrino oscillation in a 250 km long-baseline experiment

The K2K experiment observes indications of neutrino oscillation: a reduction of nu(mu) flux together with a distortion of the energy spectrum. Fifty-six beam neutrino events are observed in Super-Kamiokande (SK), 250 km from the neutrino production point, with an expectation of 80.1(+6.2)(-5.4). Twenty-nine one ring mu-like events are used to reconstruct the neutrino energy spectrum, which is better matched to the expected spectrum with neutrino oscillation than without. The probability that the observed flux at SK is explained by statistical fluctuation without neutrino oscillation is less than 1%.