Metal oxide coating on carbon nanotubes by a methanol-thermal method

A methanol-thermal method has been developed to fabricate one-dimensional composite nanowires by coating multiwalled carbon nanotubes with lanthanum oxide and iron oxide, respectively. The coating structure and composition have been investigated by transmission electron microscopy and the X-ray energy dispersive spectrum. Magnetic measurement for the iron oxide coatings indicated that the coercivity has been enhanced after coating. The method reported here provides a novel procedure for the fabrication of one-dimensional composite nanostructures.

Deterministic approach to the generation of modified helical beams for optical manipulation

We present a deterministic method to generate modified helical beams which create optical vortices with desired dark core intensity patterns in the far-field. The experiments are implemented and verified by a spatial light modulator (SLM), which imprints a phase function onto the incident wavefront of a TEM00 laser mode to transform the incident beam into a modified helical beam. The phase function can be calculated once a specific dark core shape of an optical vortex is required. The modified helical beam is exploited in optical manipulation with verification of its orbital angular momentum experimentally.

Characterization of a novel HLA-DQB1 allele, DQB1*020102

A novel human leukocyte antigen (HLA)-DQB1 allele, DQB1*020102, was detected in a 28-year-old woman of Han ethnic in Guangzhou, China. Compared with HLA-DQB1*020101 and HLA-DQB1*0202, they differed in only one nucleotide at the position 167 (C to T) of exon 2, which was a highly conserved position. This is a synonymous mutation, which does not cause any change in the amino acid sequence of mature protein.

Isolation and molecular characterization of fluoroquinolone-resistant Escherichia coli from poultry litter

Nineteen fluoroquinolone-resistant Escherichia coli strains were isolated from poultry litter. Sixteen of the 19 strains were serotyped to groups 6, 8, 53, 56, 153, and 174. Three strains were not serotyped to any known group. All isolates were resistant to multiple antibiotics. Most strains were resistant to gentamicin, kanamycin, chloramphenicol, and streptomycin. Ribotyping of the multidrug-resistant isolates with restriction enzyme PvuII showed 5 different ribogroups, suggesting independent development of resistance instead of clonal spread. Quinolone resistance was associated with mutations of the quinolone resistance-determining region (QRDR) of the gyr A gene in all cases. To determine the incidence of gyr A mutations in fluoroquinolone-resistant E. coli isolates, a rapid PCR-based assay was used by amplifying a 164-bp region of the gyr A gene containing the mutation sites followed by digestion of the PCR product with restriction enzyme HinfI. A higher level of resistance to ciprofloxacin [minimum inhibitory concentration (MIC) >4 microg] was associated with double mutations, but the mutants with a low level of resistance (MIC <2 microg) had only a single mutation. Those strains that were ciprofloxacin-resistant (MIC <2 microg) had a single mutation of a C-to-T transition at position 248 (Ser 83-->Leu) or a G-to-A transition at position 259 (Asp 87-->Asn). The ciprofloxacin-resistant (MIC >4 microg) isolates had mutations at both positions. Fluoroquinolone resistance was present among different serotypes and ribotypes, and drug resistance profiles suggest that the incidence of resistance does not indicate a clonal population in avian E. coli.

A novel HLA-DRB1*09 allele, HLA-DRB1*090103*, isolated from the Han population of Guangdong, China

A novel HLA-DRB1*09 allele, HLA-DRB1*090103, has been identified in a Guangdong Han person. Its sequence was confirmed by sequencing polymerase chain reaction products and clones. This allele differed by one nucleotide from HLA-DRB1*090102 at position 50(G-->C), which represents a silent mutation.

Evaluation of adipocyte apoptosis by laser scanning cytometry

OBJECTIVE

Adipocyte apoptosis plays an important role in adipose tissue homeostasis and can be altered under a variety of physiological and pathological conditions. This study was carried out to determine whether laser scanning cytometry (LSC) can be used to measure changes in apoptosis of adipocytes over time.

DESIGN

LSC was used to investigate adipocyte apoptosis induced by tumor necrosis factor-alpha (TNF-alpha), a cytokine that is associated with obesity and insulin resistance. LSC, a slide-based solid phase cytofluorometer, provides quantitative flow fluorescence data together with morphological information for apoptotic detection. Both 3T3-L1 cells and rat adipocytes from primary cell culture were incubated with 0 or 25 nM TNF-alpha for up to 24 h. Both the FITC-conjugated annexin V/propidium iodide assay and the TUNEL assay were used to distinguish cells with apoptotic characteristics from nonapoptotic cells.

RESULTS

Apoptosis did not increase over time in the absence of TNF-alpha for both 3T3-L1 cells and rat primary adipocytes. For both 3T3-L1 cells and rat primary adipocytes, a significant increase in the percentage of apoptotic cells was observed by 3-4 h incubation with TNF-alpha (P<0.05). By 24 h, more than 50% of cells incubated with TNF-alpha were apoptotic (P<0.001). This process was also associated with morphological changes typical of adipocytes undergoing apoptosis. By estimating the percentage of cell subpopulations after different times of incubation with TNF-alpha, we were able to develop grading parameters, based on the adipose apoptotic measurements.

CONCLUSION

With morphological information, LSC can be a useful tool to evaluate adipocyte apoptosis.

Identification of a novel HLA-DPB1 allele--DPB1*0102

In this report, we describe the identification of a novel HLA-DPB1 allele, DPB1*0102, which was first found in a 27-year-old woman and was later detected again in another person, from the Han population of China. According to the nucleotide alignment, DPB1*0102 was the most similar to DPB1*0202, with only one nucleotide substitution from A to G at position 192 among three closely related alleles--DPB1*0202, DPB1*2401 and DPB1*0501. This substitution was a non-synonymous one, which caused a change of amino acid from E to K at codon 69 of DP beta-chain in the mature protein.

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.

Inhibition of AKT survival pathway by a small molecule inhibitor in human endometrial cancer cells

The PTEN (phosphatase and tensin homolog deleted on chromosome 10) tumour suppressor is mutated in 40–50% of human endometrial cancers. PTEN exerts its effects in part via inhibition of the antiapoptotic protein AKT. We demonstrate that two endometrial cancer cell lines that harbour PTEN mutations, Ishikawa and RL95-2, have high levels of phosphorylated AKT and high AKT kinase activity. Two additional endometrial cancer cell lines that express wild-type PTEN, Hec1A and KLE, have little phosphorylated AKT and minimal demonstrable AKT kinase activity. We tested a potential inhibitor of the AKT pathway, API-59CJ-OMe, in these four cell lines. We found that API-59CJ-OMe inhibits AKT kinase activity and induces apoptosis in the Ishikawa and RL95-2 cell lines with high AKT activity, but has little effect on Hec1A and KLE cells without AKT activity. API-59CJ-OMe may therefore have therapeutic potential for those endometrial cancers that harbour PTEN mutations and AKT activation.

Effects of strapping the tendo-Achilles

SA Sports Medicine Vol.15(2) 2003: 9-13

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.

Too much short chain fatty acids cause neonatal necrotizing enterocolitis

Nenatal necrotizing enterocolitis (NEC) is a disease mainly affects premature infants. It is well known that prematurity, enteral formula feeding, and bacterial colonization are three major risk factors for NEC. Acetic acid, propionic acid and butyric acid are short chain fatty acids (SCFAs), which are produced mainly in the colon by bacterial fermentation of undigested carbohydrates. Although luminal production of modest quantities of SCFAs is essential for normal colonic mucosal function, excessive production/accumulation of SCFAs may arise in premature infants due to increased luminal carbohydrates malabsorption and poor gastrointestinal motility, and may have deleterious effects on mucosal integrity. Therefore, it is proposed that too much luminal short chain fatty acids cause neonatal NEC.

Role of data aggregation in biosurveillance detection strategies with applications from ESSENCE

INTRODUCTION

Syndromic surveillance systems are used to monitor daily electronic data streams for anomalous counts of features of varying specificity. The monitored quantities might be counts of clinical diagnoses, sales of over-the-counter influenza remedies, school absenteeism among a given age group, and so forth. Basic data-aggregation decisions for these systems include determining which records to count and how to group them in space and time.

OBJECTIVES

This paper discusses the application of spatial and temporal data-aggregation strategies for multiple data streams to alerting algorithms appropriate to the surveillance region and public health threat of interest. Such a strategy was applied and evaluated for a complex, authentic, multisource, multiregion environment, including >2 years of data records from a system-evaluation exercise for the Defense Advanced Research Project Agency (DARPA).

METHODS

Multivariate and multiple univariate statistical process control methods were adapted and applied to the DARPA data collection. Comparative parametric analyses based on temporal aggregation were used to optimize the performance of these algorithms for timely detection of a set of outbreaks identified in the data by a team of epidemiologists.

RESULTS

The sensitivity and timeliness of the most promising detection methods were tested at empirically calculated thresholds corresponding to multiple practical false-alert rates. Even at the strictest false-alert rate, all but one of the outbreaks were detected by the best method, and the best methods achieved a 1-day median time before alert over the set of test outbreaks.

CONCLUSIONS

These results indicate that a biosurveillance system can provide a substantial alerting-timeliness advantage over traditional public health monitoring for certain outbreaks. Comparative analyses of individual algorithm results indicate further achievable improvement in sensitivity and specificity.

A novel HLA-DRB1 allele, DRB1*0449, with a rare point mutation found in the Han population of Guangdong China

Anovel HLA-DRB1 allele, DRB1*0449, has been identified in the Han population of Guangdong Province of China. Compared with DRB1*0406, it has only one single-nucleotide mutation from G to A at position 18 of exon 2, which causes a change in the protein sequence from valine to isoleucine at codon 11 of DR beta chain.

School bag carriage and pain in school children

PURPOSE

In South Africa (SA), anecdotal evidence for the incidence of shoulder, back and neck pain in school children is alarming but no scientific studies have confirmed this impression. The purpose of the present study was to determine the relationship between pain and school bag carriage in scholars in Durban, SA.

METHOD

A study was carried out at four different schools in the Verulam and Chatsworth Regions in Kwa-Zulu Natal, SA. Schools were selected by convenience. One hundred and seventy six scholars between the ages of 11 and 14 years correctly filled out a questionnaire with open-ended and closed-ended questions. Each child also had his/her body and bag weight measured.

RESULTS

In this study, most of the scholars experienced shoulder and a combination of shoulder and other bodily pain. The majority of the children carried backpacks over two shoulders. The type of bag carried was significantly related to pain experienced (0.00). A significantly larger number of female scholars experienced pain.

CONCLUSION

The shoulder and other bodily pain experienced by the sample of scholars are strongly related to the type of bag and the gender of the children. More in-depth studies into identifying risk factors for bodily pains in school children are indicated.

An alarming rate of drug-resistant tuberculosis at Ngwelezane Hospital in northern KwaZulu Natal, South Africa

OBJECTIVE

To obtain a profile of tuberculosis (TB) cases caused by Mycobacterium tuberculosis in northern KwaZulu Natal (KZN) for 2001.

METHOD

The demographic and drug resistance characteristics were determined. A total of 251 smear and culture confirmed cases was obtained and the resistance of three major anti-tuberculosis drugs was tested using the proportion method.

RESULTS

The patients were mainly from Ngwelezane (57.8%), Stanger (23.5%) and Manguzi (18.7%); 59.0% were male; 54.2% of the isolates were obtained from new TB patients. The mean age of the TB patients was 29.6 years, with the maximum notification age range at 25-34 years. A high prevalence of drug-resistant and multiresistant TB was observed in this region. At least 55% of previously treated and 19% of new cases from all areas were resistant to at least one of the drugs tested. New patients from Ngwelezane and Manguzi area had a high prevalence of any rifampicin resistance (11.0%) and ethambutol resistance (3.9%), respectively.

CONCLUSION

Our results indicate that the TB epidemic in northern KZN, especially in Ngwelezane, is severe. An infrastructure to educate stakeholders about the need to ensure consistency in treatment is needed.

A modified p53 enhances apoptosis in sarcoma cell lines mediated by doxorubicin

Mdm2 is frequently overexpressed in sarcoma cells and may contribute to drug resistance by increasing p53 degradation. We investigated the induction of apoptosis in sarcoma cells via adenovirus-mediated gene transfer of wild-type p53 and two modified p53 genes, p53 14/19 and p53 22/23, whose protein products are resistant to Mdm2-mediated degradation. We found that adenovirus-wt p53 (Ad-wt p53) induces significant apoptosis in HT1080 fibrosarcoma cells expressing low levels of Mdm2, but fails to induce apoptosis in SJSA osteosarcoma cells expressing high levels of Mdm2. In contrast, Ad-p53 14/19 induces significant apoptosis in both cell lines. Interestingly, Ad-p53 22/23, a vector encoding a transcription-defective p53 mutant, causes limited apoptosis in both cell lines. We demonstrate that doxorubicin induces phosphorylation of both wt p53 and p53 14/19 protein at multiple sites. We tested the efficacy of doxorubicin and cisplatin with either Ad-wt p53, Ad-p53 22/23 or Ad-p53 14/19. SJSA cells, although harbouring endogenous wt p53, did not undergo significant apoptosis following doxorubicin or cisplatin exposure alone or combined with Ad-wt p53. In contrast, doxorubicin or cisplatin plus Ad-p53 14/19 induced significant apoptosis. Gene transfer of p53 14/19 in combination with the administration of doxorubicin or cisplatin is a potential therapeutic approach for cancers expressing high levels of Mdm2.

Ventral brainstem enterogenous cyst: an unusual location

Enterogenous cysts mostly locate in the spinal canal and have only rarely been reported in an intracranial site. We report a case of enterogenous cyst in the ventral to brainstem. The 45-year-old woman presented with paroxysmal headache and diplopia. A CT scan and MRI revealed a cystic clival mass from midbrain to medulla. Subtotal resection was performed using a sub-temporal approach and the patient made a good recovery. Pathological examination revealed that the lesion was a typical enterogenous cyst.