bluuebunny/crossref_metadata_2025 huggingface dataset:
Alterations of the SWI/SNF chromatin remodelling subunit‐BRG1 and BRM in hepatocellular carcinoma
Authors: Endo Mio , Yasui Kohichiroh , Zen Yoh , Gen Yasuyuki , Zen Keika , Tsuji Kazuhiro , Dohi Osamu , Mitsuyoshi Hironori , Tanaka Shinji , Taniwaki Masafumi , Nakanuma Yasuni , Arii Shigeki , Yoshikawa Toshikazu
Published: October 2012

Background

The SWI/SNF chromatin remodelling complex, which contains either brahma‐related gene‐1 (BRG1) or brahma (BRM) as the catalytic ATPase, functions as a master regulator of gene expression.

Aims

To examine alterations of BRG1 and BRM in hepatocellular carcinoma (HCC).

Methods

We investigated DNA copy number aberrations in human HCC cell lines using a high‐density oligonucleotide microarray. We determined DNA copy numbers and expression levels of BRG1 and BRM genes in primary HCC tumours, and conducted further searches for mutations in BRG1 and BRM genes.

Results

Homozygous deletion of the BRG1 gene was found in HCC cell line SNU398. Copy number losses of BRG1 and BRM genes were observed in 14 (26%) and 7 (13%) of 54 primary HCC tumours respectively. We found four somatic missense mutations in the BRG1 gene in two of 36 primary HCC tumours, but no mutations in BRM gene. Expression of BRM mRNA, but not BRG1 mRNA, was significantly reduced in primary HCC tumours, compared to non‐tumour tissue counterparts. Immunohistochemical analyses of non‐tumour liver tissues showed that BRM protein was expressed in hepatocytes and bile‐duct epithelial cells, whereas BRG1 protein was expressed in bile‐duct epithelial cells, but not in hepatocytes. BRM protein expression was lost in nine (22.5%) of 40 HCC tumours. Loss of BRM protein expression was significantly associated with poor overall survival.

Conclusion

Reduced expression of BRM may contribute to the carcinogenesis of HCC. Although deletions and mutations in BRG1 gene were identified, the role of BRG1 in HCC tumourigenesis remains unclear.
The activity of γδ T cells against paediatric liver tumour cells and spheroids in cell culture
Authors: Hoh Alexander , Dewerth Alexander , Vogt Fabian , Wenz Julia , Baeuerle Patrick A. , Warmann Steven W. , Fuchs Joerg , Armeanu‐Ebinger Sorin
Published: October 2012

Background

Chemoresistance and advanced tumour stage at time of diagnosis are the major reasons for poor treatment results in hepatoblastoma (HB) and paediatric hepatocellular carcinoma (HCC). Positive results with transplantation of liver and bone marrow revealed the impact of the immune system on the treatment of liver malignancies.

Aim

Cytotoxic‐immune‐cells‐like natural killer (NK) and T cells are major player in the defence against developing tumours. This study aimed to specifically analyse the ability of ex‐vivo expanded γδ T cells to recognise and lyse HB and HCC cell lines in coculture assays.

Methods

Cell viability after treatment with γδ T cells was evaluated with two HB (HUH6 and HepT1) and one HCC cell line (HC‐AFW1) using a MTT‐based cytotoxicity assay. The binding of T cells to target cells was monitored using immunofluorescence microscopy.

Results

Incubation of hepatic tumour cell lines with γδ T cells led to a significant decrease in tumour cell viability. This was enhanced by zoledronic acid and histone deacetylase inhibitors. MT110, an EpCAM/CD3‐bispecific BiTE antibody could bluntly enhance tumour cell lysis close to completion. γδ T cells efficiently interacted with HB and HCC cells in a spheroid culture model.

Conclusion

Bispecific antibodies such as MT110 might be used to intensify the antitumoural effect of γδ T cells in context of adoptive immune cell transfer. Optimised immunotherapeutic strategies might therefore improve the outcome of high risk hepatoblastoma and hepatocellular carcinoma.
OnobotulinumtoxinA Has No Effects on Growth of LNCaP and PC3 Human Prostate Cancer Cells
Authors: CHENG Yuan‐Tso , CHUNG Yueh‐Hua , KANG Hong‐Yo , TAI Ming‐Hong , CHANCELLOR Michael B. , CHUANG Yao‐Chi
Published: October 2012

Objectives: Intraprostatic injection of botulinum toxin (BTX) has been reported to have therapeutic effects on lower urinary tract symptoms related to benign prostate hyperplasia (BPH). Patients with BPH are at risk of having prostate cancer. The present study was conducted to assess the effect of onobotulinumtoxinA on prostate cancer in vitro and in vivo.

Methods: Human prostate cancer cell lines, LNCaP and PC3 were exposed to different doses of onobotulinumtoxinA (0–10 U; Allergan, Irvine, CA, USA). Cell viability, DNA fragmentation and apoptosis assay were subsequently measured. For the in vivo study, LNCaP and PC3 xenografts were introduced into nude mice and treated with intra‐tumoral onobotulinumtoxinA or saline injection. Tumor volume, histopathology and apoptosis were assessed. Presence of SNAP‐25 protein, the molecular target of onobotulinumtoxinA, was studied in both cell lines by Western blot analysis.

Results: OnobotulinumtoxinA did not significantly affect cell proliferation or apoptosis in LNCaP and PC3 cells. There was no significant difference in tumor size and histopathological findings between the experimental and control groups. There was no detectable SNAP‐25 protein in both cell lines.

Conclusion: OnobotulinumtoxinA does not affect the growth of LNCaP or PC3 cells in vitro and in vivo or produce significant anti‐tumor effects. Intraprostatic BTX injection for BPH might not affect the growth of prostate cancer.
Spatial and temporal patterns of genetic variation in the widespread antitropical deep‐sea coral Paragorgia arborea
Authors: Herrera S. , Shank T. M. , Sánchez J. A.
Published: October 2012

Numerous deep‐sea species have apparent widespread and discontinuous distributions. Many of these are important foundation species, structuring hard‐bottom benthic ecosystems. Theoretically, differences in the genetic composition of their populations vary geographically and with depth. Previous studies have examined the genetic diversity of some of these taxa in a regional context, suggesting that genetic differentiation does not occur at scales of discrete features such as seamounts or canyons, but at larger scales (e.g. ocean basins). However, to date, few studies have evaluated such diversity throughout the known distribution of a putative deep‐sea species. We utilized sequences from seven mitochondrial gene regions and nuclear genetic variants of the deep‐sea coral Paragorgia arborea in a phylogeographic context to examine the global patterns of genetic variation and their possible correlation with the spatial variables of geographic position and depth. We also examined the compatibility of this morphospecies with the genealogical‐phylospecies concept by examining specimens collected worldwide. We show that the morphospecies P. arborea can be defined as a genealogical‐phylospecies, in contrast to the hypothesis that P. arborea represents a cryptic species complex. Genetic variation is correlated with geographic location at the basin‐scale level, but not with depth. Additionally, we present a phylogeographic hypothesis in which P. arborea originates from the North Pacific, followed by colonization of the Southern Hemisphere prior to migration to the North Atlantic. This hypothesis is consistent with the latest ocean circulation model for the Miocene.
Perceptions of patient education during hospital visit – described by school‐age children with a chronic illness and their parents
Authors: Kelo Marjatta , Eriksson Elina , Eriksson Ilse
Published: October 2012

Background

Families having a child with a chronic disease face changes in their everyday lives, and the whole family is involved in patient education. Nurses bear a great responsibility for patient education, but their school‐age patients’ and their parents’ perceptions of patient education have only been studied to a limited extent.

Aim

The current study aimed to explore the elements of significant patient education events during a hospital visit described by school‐age children with a chronic illness and their parents.

Method

The design was qualitative and descriptive. A total of nineteen Finnish parents and their 12 children aged 5–12, suffering from chronic diseases, were interviewed using a critical incident technique. The data were analysed by deductive content analysis.

Findings

The descriptions of patient education comprised cases with parents’ shock at the outset of the patient education sessions and cases with the outcome of these sessions, including an experience of empowerment or lack of it. The patient education practices were examined by determining nursing, didactic and interpersonal competences. Nursing competence involved illustrations of knowledge and the ability to care for children and families as well as knowledge of the disease and its management. Didactic competence comprised practical examples of knowledge of teaching and the ability to implement the education process. Interpersonal competence manifested itself in the ability to have a dialogue.

Conclusion

The findings show the importance of comprehensive patient education competence required of nurses giving education to families having children with chronic illnesses. This knowledge can be applied to promote nurses’ professional training and to develop patient education.
Aberrant sodium channel activity in the complex seizure disorder of Celf4 mutant mice
Authors: Sun Wenzhi , Wagnon Jacy L. , Mahaffey Connie L. , Briese Michael , Ule Jernej , Frankel Wayne N.
Published: October 2012

Key points

Inappropriate electrochemical signalling between neurons is a central problem in epilepsy. Only a fraction of all heritable epilepsies are solved, and many are due to ion channel mutations.

Ion channels are cell surface molecules that initiate and coordinate electrochemical signalling, by allowing the right combination of ions to flow in and out of a neuron.

Ion channels may be regulated by other genes. We recently determined that the RNA‐binding protein, ‘CELF4’, affects expression of many molecules, including ion channels, to coordinate electrochemical signalling.

Here we conclude that a sodium channel called Nav1.6 is the primary instigator of abnormal excitation when CELF4 is impaired.

Nav1.6 expression is increased in the axon initial segment – a part of the neuron that initiates electrical activity – altering intrinsic excitability. We surmise that in a brain that already has difficulty regulating other molecules due to CELF4 deficiency, this leads to uncontrolled network excitation and seizures.

Abstract  Mice deficient for CELF4, a neuronal RNA‐binding protein, have a complex seizure disorder that includes both convulsive and non‐convulsive seizures, and is dependent upon Celf4 gene dosage and mouse strain background. It was previously shown that Celf4 is expressed predominantly in excitatory neurons, and that deficiency results in abnormal excitatory synaptic neurotransmission. To examine the physiological and molecular basis of this, we studied Celf4‐deficient neurons in brain slices. Assessment of intrinsic properties of layer V cortical pyramidal neurons showed that neurons from mutant heterozygotes and homozygotes have a lower action potential (AP) initiation threshold and a larger AP gain when compared with wild‐type neurons. Celf4 mutant neurons also demonstrate an increase in persistent sodium current (INaP) and a hyperpolarizing shift in the voltage dependence of activation. As part of a related study, we find that CELF4 directly binds Scn8a mRNA, encoding sodium channel Nav1.6, the primary instigator of AP at the axon initial segment (AIS) and the main carrier of INaP. In the present study we find that CELF4 deficiency results in a dramatic elevation in the expression of Nav1.6 protein at the AIS in both null and heterozygous neurons. Together these results suggest that activation of Nav1.6 plays a crucial role in seizure generation in this complex model of neurological disease.
Astrocytic GABA transporter GAT‐1 dysfunction in experimental absence seizures
Authors: Pirttimaki Tiina , Parri H. Rheinallt , Crunelli Vincenzo
Published: October 2012

Key points

Enhanced thalamic tonic GABA inhibition plays a role in experimental absence seizures.

In this study we investigated astrocytic GABA transporter function and gliotransmitter release in an absence seizure rat model.

GAT‐1 GABA transporter currents in thalamic astrocytes were reduced in an absence seizure rat model.

Spontaneous phasic astrocytic GABA events displayed kinetic differences between absence seizure model rats and non‐epileptic controls.

Spontaneous phasic astrocyte glutamate release was not different in absence seizure model rats and non‐epileptic controls.

Abstract  An enhanced tonic GABAA inhibition in the thalamus plays a crucial role in experimental absence seizures and has been attributed, on the basis of indirect evidence, to a dysfunction of the astrocytic GABA transporter‐1 (GAT‐1). Here, the GABA transporter current was directly investigated in thalamic astrocytes from a well‐established genetic model of absence seizures, the genetic absence epilepsy rats from Strasbourg (GAERS), and its non‐epileptic control (NEC) strain. We also characterized the novel form of GABAergic and glutamatergic astrocyte‐to‐neuron signalling by recording slow outward currents (SOCs) and slow inward currents (SICs), respectively, in thalamocortical (TC) neurons of both strains. In patch‐clamped astrocytes, the GABA transporter current was abolished by combined application of the selective GAT‐1 and GAT‐3 blocker, NO711 (30 μm) and SNAP5114 (60 μm), respectively, to GAERS and NEC thalamic slices. NO711 alone significantly reduced (41%) the transporter current in NEC, but had no effect in GAERS. SNAP5114 alone reduced by half the GABA transporter current in NEC, whilst it abolished it in GAERS. SIC properties did not differ between GAERS and NEC TC neurons, whilst moderate changes in SOC amplitude and kinetics were observed. These data provide the first direct demonstration of a malfunction of the astrocytic thalamic GAT‐1 transporter in absence epilepsy and support an abnormal astrocytic modulation of thalamic ambient GABA levels. Moreover, while the glutamatergic astrocyte–neuron signalling is unaltered in the GAERS thalamus, the changes in some properties of the GABAergic astrocyte–neuron signalling in this epileptic strain may contribute to the generation of absence seizures.
Experimental study of electric field screening by the proximity of two carbon fiber cathodes
Authors: Tang Wilkin , Shiffler Don , Golby Ken , LaCour Matthew , Knowles Tim
Published: October 2012

This paper describes the first experiments that use only two carbon fiber field emitters with different separations to quantify and isolate the effect of electric field screening. Experiments show that when the separation between the two carbon fiber cathodes decreases, both the effective field enhancement factor, βeff, and the current emission decreases. For a two-emitter geometry, our experiment suggests a height of approximately 1.5 times the separation between the two cathodes as the optimum ratio to optimize the emitted current. The paper shows the analysis of the turn on voltage of the field emitters for different separations. The authors compare experimental data with Fowler–Nordheim field emission theory and particle-in-cell simulation, showing good agreement between experiment, theory, and modeling.
P450 Oxidoreductase Deficiency: A Disorder of Steroidogenesis with Multiple Clinical ManifestationsA Presentation from the European Society for Paediatric Endocrinology (ESPE) New Inroads to Child Health (NICHe) Conference on Stress Response and Child Health in Heraklion, Crete, Greece, 18 to 20 May 2012.
Authors: Miller Walter L.
Published: October 2012

Mutant forms of an enzyme required for steroid synthesis and drug metabolism result in a range of clinical symptoms.
The Effect of Acute and Chronic Stress on GrowthA Presentation from the European Society for Paediatric Endocrinology (ESPE) New Inroads to Child Health (NICHe) Conference on Stress Response and Child Health in Heraklion, Crete, Greece, 18 to 20 May 2012.
Authors: Sävendahl Lars
Published: October 2012

The glucocorticoids and inflammatory cytokines induced by stress can impair bone growth.
Science Signaling
Podcast: 23 October 2012
Authors: Nimer Stephen D. , VanHook Annalisa M.
Published: October 2012

A progrowth signal can mediate feedback that reduces cell proliferation and stem cell self-renewal.
Cleave and Leave
Authors: Hines Pamela J.
Published: October 2012

The plant hormone ethylene triggers cleavage and translocation to the nucleus of a signaling component.
Transcription Around the Clock
Authors: Kiberstis Paula A.
Published: October 2012

The mammalian circadian clock controls the daily oscillation of transcript abundance through both transcriptional and posttranscriptional events, and an RNA-binding protein links changes in body temperature to the mammalian circadian clock.
Neuroprotective Mitochondrial Glutamate Receptors
Authors: Gough Nancy R.
Published: October 2012

Mitochondria isolated from rat brain have NMDA-type glutamate receptors that appear to enhance mitochondrial calcium buffering capacity.
Sphenoid sinus mucocele
Authors: Bahgat Mohammed , Bahgat Yassin , Bahgat Ahmed
Published: October 2012

The authors present their experience of managing an interesting case of a 65-year-old woman who presented to their clinic with 1-month history of persistent deep-seated headache. The patient sought medical advice in neurology and ophthalmology clinics before being referred to the ear, nose and throat clinic. CT imaging revealed isolated opacification and expansion of both sphenoid sinuses with bony continuity along the periphery of the sinuses features consistent with mucocele. MRI was needed to fully evaluate the extension of the lesion. The lesion was diagnosed as bilateral sphenoid sinuses mucoceles. Transnasal endoscopic drainage of the sphenoid mucoceles leads to gradual improvement of the symptoms. We discuss the clinical presentation, diagnosis and treatment of this case as well as a review of the literature.
An interesting finding in a congenital cystic adenomatoid malformation
Authors: Jones Katherine Elizabeth , Teo Ying , Lakhoo Kokila
Published: October 2012

Here we describe a case of antenatally diagnosed congenital cystic adenomatoid malformation. Due to increasing cyst size and fetal hydrops an antenatal drain was inserted. The lesion was excised surgically soon after birth due to significant respiratory distress. During histological assessment an area of squamous metaplasia was found within the cyst wall. This developed as a result of the drain placement. At 4-year follow-up the child remains well and has experienced no long-term respiratory sequalae.
Closure of a large high-output gastrocutaneous fistula with combined postpyloric feeding and aggressive medical therapy
Authors: Vasant Dipesh Harshvadan , Lal Simon , Blackett Brenda D , Paine Peter A
Published: October 2012

Widening of the exit site of a percutaneous gastrostomy tube is a rare but difficult to manage complication, which leads to significant morbidity as a result of caustic material leak and associated cutaneous injury. Such defects fail to close with conservative measures such that invasive (surgical or endoscopic) intervention is often required. The authors present a 49-year-old woman with neurological dysphagia, 2 years after gastrostomy tube insertion with several months’ history of leakage and widening of the hole at the exit site. Following gastrostomy tube removal; the patient was left with a large, high-output gastrocutaneous fistula which was treated aggressively with measures to reduce gastric discharge including ‘nil-by-mouth’, bypassing the stomach with distal feeding, administration of a somatostatin analogue, high-dose proton pump inhibitor and prokinetics with the aim of preoperatively downsizing the wound. This novel approach led to complete closure of the large gastrocutaneous fistula, obviating the need for surgical intervention.
Bevacizumab-related osteonecrosis of the mandible is a self-limiting disease process
Authors: Bettini Giordana , Blandamura Stella , Saia Giorgia , Bedogni Alberto
Published: October 2012

A female patient with non-small-cell lung cancer presented with a huge area of exposed bone in the mandible following spontaneous teeth loss. She was receiving multimodal chemotherapy containing bevacizumab. No previous treatment with bisphosphonates or comorbid conditions was reported. Pain medications and infection control were offered to the patient who was closely followed up. Initial imaging and histology of bone and surrounding mucosa (8 weeks after bevacizumab cessation) confirmed the clinical suspicion of avascular osteonecrosis of the mandible. Subsequent imaging and histology of bone and gingiva (12 weeks after bevacizumab cessation) revealed the initial sequestration of the mandible with a marked expansion of the mucosal vascular network. Spontaneous bone sequestration eventually occurred few months later, followed by stable and painless mucosal coverage of the mandibular bone. The patient remained disease-free up to 3 years of follow-up.
Pull-out test and discrete spring model of fibre-reinforced polymer perfobond rib shear connector
Authors: Cho Jeong-Rae , Park Sung Yong , Cho Keunhee , Kim Sung Tae , Kim Byung-Suk
Published: October 2012

In this study, a series of pull-out tests on fibre-reinforced polymer (FRP) perfobond rib shear connectors were conducted to investigate their shear behavior. The test specimens were designed to examine only the effects of the resistance by rib holes. The test variables were the size and number of rib holes. In the tests, the resistance by concrete dowel action was practically linearly proportional to the area of the rib hole. However, the resistance appeared to be nonlinearly proportional to the number of rib holes with a slight loss for a larger number of the rib holes, due to the sequential failure of the rib holes. The constitutive equation of the discrete spring model representing the concrete dowel including post-failure frictional effects, adopting the diameter of the rib hole as parameter, was derived through regression analysis of the load – relative displacement curve obtained for specimens with a single rib hole. The proposed discrete spring model resulted in good correlation with the experimental results for specimens with a larger number of rib holes. It is expected that the derived constitutive equation would be useful for the analysis and design of structures using FRP perfobond rib shear connectors.
Molecular characterization of theblaKPC-2gene in clinical isolates of carbapenem-resistantKlebsiella pneumoniaefrom the pediatric wards of a Chinese hospital
Authors: Liu Yang , Li Xiang-Yang , Wan La-Gen , Jiang Wei-Yan , Li Fang-Qu , Yang Jing-Hong
Published: October 2012

The present study was conducted to confirm the presence of Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae associated with a nosocomial outbreak in a Chinese pediatric hospital. From July 2009 to January 2011, 124 nonduplicated K. pneumoniae isolates were collected from specimens from patients of pediatric units in the hospital. Twelve of the 124 isolates possessed the blaKPC-2gene and showed 7 different pulsed-field gel electrophoresis (PFGE) patterns. Meanwhile, 16S rRNA methylase, acc(6′)-Ib-cr, and several types of β-lactamases were also produced by the majority of the KPC-producing isolates. Class 1 integron-encoded intI1 integrase gene was subsequently found in all strains, and amplification, sequencing, and comparison of DNA between 5′ conserved segment and 3′ conserved segment region showed the presence of several known antibiotic resistance gene cassettes of various sizes. The conjugation and plasmid-curing experiments indicated some KPC-2-encoding genes were transmissible. In addition, conjugal cotransfer of multidrug-resistant phenotypes with KPC-positive phenotypes was observed in KPC-producing strains. Restriction endonuclease analysis and DNA hybridization with a KPC-specific probe showed that the blaKPC-2gene was carried by plasmid DNA from K. pneumoniae of PFGE pattern B. The overall results indicate that the emergence and outbreak of KPC-producing K. pneumoniae in our pediatric wards occurred in conjunction with plasmids coharboring 16S rRNA methylase and extended-spectrum β-lactamases.
Composition of the archaeal community involved in methane production during the decomposition of Microcystis blooms in the laboratory
Authors: Xing Peng , Li Huabing , Liu Qing , Zheng Jiuwen
Published: October 2012

We investigated the microbial processes involved in methane (CH4) production from Microcystis bloom scums at different temperatures. A Microcystis slurry was collected from Lake Taihu and incubated in airtight bottles at 15, 25, and 35 °C. The production of CH4 was monitored, and the emission rate was calculated. The dynamics of the methanogenic community were analyzed by terminal restriction fragment length polymorphism analysis of archaeal 16S rRNA genes. Phylogenetic information for the methanogens was obtained by cloning and sequencing selected samples. Significant CH4 emission from the Microcystis scums was delayed by approximately 12 days by the natural oxygen depletion process, and CH4 production was enhanced at higher temperatures. Phylogenetic analysis indicated that the archaeal community was composed of Methanomicrobiales, Methanobacteriaceae, and a novel cluster of Archaea. An apparent succession of the methanogenic community was demonstrated, with a predominance of Methanobacteriaceae at higher temperatures. Higher temperatures enhanced the methanogenic transformation of the Microcystis biomass and the phylogenetic dominance of hydrogenotrophic methanogens, suggesting that H2 and CO2 might be the primary substrates for CH4 production during Microcystis decomposition without the participation of lake sediment. This work provides insight into the microbial components involved in Microcystis biomass fermentation in controlled systems.
Possible involvement of the sco2127 gene product in glucose repression of actinorhodin production in Streptomyces coelicolor
Authors: Forero Angela , Sánchez Mauricio , Chávez Adán , Ruiz Beatriz , Rodríguez-Sanoja Romina , Servín-González Luis , Sánchez Sergio
Published: October 2012

Streptomyces coelicolor mutants resistant to 2-deoxyglucose are insensitive to carbon catabolite repression (CCR). Total reversion to CCR sensitivity is observed by mutant complementation with a DNA region harboring both glucose kinase glkA gene and the sco2127 gene. The sco2127 is located upstream of glkA and encodes a putative protein of 20.1 kDa. In S. coelicolor, actinorhodin production is subject to glucose repression. To explore the possible involvement of both SCO2127 and glucose kinase (Glk) in the glucose sensitivity of actinorhodin production, this effect was evaluated in a wild-type S. coelicolor A3(2) M145 strain and a sco2127 null mutant (Δsco2127) derived from this wild-type strain. In comparison with strain M145, actinorhodin production by the mutant was insensitive to glucose repression. Under repressive conditions, only minor differences were observed in glucose utilization and Glk production between these strains. SCO2127 was detected mainly during the first 36 h of fermentation, just before the onset of antibiotic production, and its synthesis was not related to a particular carbon source. The glucose sensitivity of antibiotic production was restored to wild-type phenotype by transformation with an integrative plasmid containing sco2127. Our results support the hypothesis that SCO2127 is a negative regulator of actinorhodin production and suggest that the effect is independent of Glk.
Identification and proposal of a potentially new clonal complex that is a common cause of MenB disease in central and eastern Canada
Authors: Tsang Raymond S.W. , Lefebvre Brigitte , Jamieson Frances B. , Gilca Rodica , Deeks Shelley L. , Zhou Jianwei
Published: October 2012

This study examined serogroup B meningococci (MenB) from invasive meningococcal disease (IMD) cases in the provinces of Québec and Ontario in the last decade by multilocus sequence typing (MLST) to determine their sequence types (STs) and clonal complexes (CCs). Forty isolates from individual MenB IMD cases were found to belong to 8 related STs, with ST-336 being the founding ST and the other 7 STs being single locus variants of ST-336. Eleven isolates belonged to ST-336, 23 belonged to ST-5571, and the other 6 were represented individually by a single different ST. All but 1 of these 40 isolates have the PorA variable-region type of P1.22,14,36. Interrogation of the Neisseria MLST web site with the present finding did not put any of the 8 related STs into known CCs. Since these 8 related STs were common causes of IMD, with ST-5571 being the most frequently identified ST in Ontario and ST-336 the third most common ST identified in Québec, we propose that ST-336 and its related STs is a potentially new meningococcal clonal complex that is endemic in the Canadian provinces of Québec and Ontario, and they constitute a common cause of IMD.
ON ELECTROWEAK BARYOGENESIS IN THE LITTLEST HIGGS MODEL WITH T-PARITY
Authors: AZIZ SAHAZADA , GHOSH BUDDHADEB
Published: October 2012

We study electroweak baryogenesis within the framework of the littlest Higgs model with T-parity. This model has shown characteristics of a strong first-order electroweak phase transition, which is conducive to baryogenesis in the early Universe. In the T-parity symmetric theory, there are two gauge sectors, viz., the T-even and the T-odd ones. We observe that the effect of the T-parity symmetric interactions between the T-odd and the T-even gauge bosons on gauge-Higgs energy functional is quite small, so that these two sectors can be taken to be independent. The T-even gauge bosons behave like the Standard Model gauge bosons, whereas the T-odd ones are instrumental in stabilizing the Higgs mass. For the T-odd gauge bosons in the symmetric and asymmetric phases and for the T-even gauge bosons in the asymmetric phase, we obtain, using the formalism of Arnold and McLerran, very small values of the ratio (Baryon number violation rate/Universe expansion rate). We observe that this result, in conjunction with the scenario of inverse phase transition in the present work and the value of the ratio obtained from the lattice result of sphaleron transition rate in the symmetric phase, can provide us with a plausible baryogenesis scenario.
THERMOELECTRIC EFFECT OF SILICON FILMS WITH SHALLOW- AND DEEP-LEVEL ACCEPTORS
Authors: HOU Q. R. , SUN J. L. , GU B. F. , CHEN Y. B. , HE Y. J.
Published: October 2012

Crystalline Si films with both shallow- and deep-level acceptors, Al and Cu , have been prepared on glass and quartz substrates by the methods of magnetron sputtering and Al -induced crystallization. Al and Cu are co-added in the Si films intermittently by regular pulse sputtering of Al and Cu targets during deposition of the Si films. By regulating the sputtering times of Al and Cu targets, the amounts of Al and Cu in the Si films can be controlled, and thus the Seebeck coefficient and electrical resistivity of the silicon films can be adjusted. It is found that the Al and Cu co-doped Si film has a larger Seebeck coefficient and a lower electrical resistivity at higher temperatures, as compared with that of only Al -doped Si film. As a result, the thermoelectric power factor of the Al and Cu co-doped Si film is greatly enhanced. The present experimental results will not only help us to understand the basic thermoelectric properties of semiconductors doubly doped with shallow- and deep-level impurities, but also open the possibility of enhancement of thermoelectric power factor by using this concept.
MATRIX PRODUCT STATE REPRESENTATION FOR SLATER DETERMINANTS AND CONFIGURATION INTERACTION STATES
Authors: SILVI PIETRO , ROSSINI DAVIDE , FAZIO ROSARIO , SANTORO GIUSEPPE E. , GIOVANNETTI VITTORIO
Published: October 2012

Slater determinants are product states of filled quantum fermionic orbitals. When they are expressed in a configuration space basis chosen a priori, their entanglement is bound and controlled. This suggests that an exact representation of Slater determinants as finitely-correlated states is possible. In this paper we analyze this issue and provide an exact Matrix Product representation for Slater determinant states. We also argue possible meaningful extensions that embed more complex configuration interaction states into the description.
SURVEILLANCE OF DIABETES PREVALENCE RATE THROUGH THE DEVELOPMENT OF A MARKOV-BASED CONTROL CHART
Authors: DOKOUHAKI PERSHANG , NOOROSSANA RASSOUL
Published: October 2012

In the field of statistical process control (SPC), usually two issues are addressed; the variables and the attribute quality characteristics control charting. Focusing on discrete data generated from a process to be monitored, attributes control charts would be useful. The discrete data could be classified into two categories; the independent and auto-correlated data. Regarding the independence in the sequence of discrete data, the typical Shewhart-based control charts, such as p-chart and np-chart would be effective enough to monitor the related process. But considering auto-correlation in the sequence of the data, such control charts would not workanymore. In this paper, considering the auto-correlated sequence of X1, X2,…, Xt,… as the sequence of zeros or ones, we have developed a control chart based on a two-state Markov model. This control chart is compared with the previously developed charts in terms of the average number of observations (ANOS) measure. In addition, a case study related to the diabetic people is investigated to demonstrate the applicability and high performance of the developed chart.
TWO-PHASE MODEL IN VISCOELASTICITY AND VISCOPLASTICITY OF SEMICRYSTALLINE POLYMERS
Authors: DROZDOV A. D. , DUSUNCELI N.
Published: October 2012

Observations are reported on isotactic polypropylene in tensile relaxation tests and in loading–unloading tests followed by relaxation after retraction at temperatures ranging from room temperatures up to 100°C. A two-phase constitutive model is developed for the mechanical response of semicrystalline polymers where crystalline and amorphous phases are treated as viscoelastoplastic continua with different laws of plastic flow. Adjustable parameters in the stress–strain relations are found by fitting the observations. Ability of the model to describe characteristic features of the viscoelastic and viscoplastic behavior of polypropylene at various temperatures is confirmed by numerical simulation and comparison of its results with experimental data in additional tests.
THEORETICAL DESCRIPTION OF METHANE HYDRATE EQUILIBRIUM IN A WIDE RANGE OF TEMPERATURE AND PRESSURE
Authors: ZHDANOV RAVIL , SUBBOTIN OLEG , CHEN LI-JEN , BELOSLUDOV VLADIMIR
Published: October 2012

Theoretical approach was developed for description of clathrate hydrates stability area at low and modestly high temperatures on molecular level. The approach permits to account for interactions between guest molecules and dependence of unit cell structure upon guest's sort, temperature and pressure. Non-ideality of the gas phase was accounted using Van-der-Waals equation of state. Within this approach, methane hydrate calculations have been performed both for low temperature and low pressure region (in equilibrium with ice Ih) and for modestly high temperatures and pressures (in equilibrium with liquid pure water). Calculations show the notable dependence of hydrates thermodynamic properties upon the guest-guest interactions. For methane hydrates, the guest-guest interaction energy can reach 10% of the guest-host value. The results of calculations are in good agreement with available experimental data. This method is applicable for accurate prediction of clathrate hydrate stability in a wide range of P–T conditions.
CHARGE TRANSPORT AND LIGHT ABSORPTION IN CONJUGATED SYSTEMS FROM EXTENDED HÜCKEL METHOD AND MARCUS THEORY
Authors: TO TRAN THINH , ADAMS STEFAN
Published: October 2012

A simple first principle model was developed based on extended Hückel-type orbital calculation, Marcus electron transport theory and two-dimensional-electron-gas model for the treatment of charge transport in conjugated polymers. Though simple and easy to compute, the effect of the applied electric-field is factored in. Based on this, a complete one-dimensional device model with a single layer of conjugated polymer sandwiched between two electrodes was developed with poly(3-hexylthiophene) (P3HT) as a case study. Simulated J-V curves show that π-π charge transport is much more pronounced than intra-chain transport, hence agree with previous findings. Using the same framework, we also calculated the absorption spectra of P3HT by considering the electronic energy barrier for electronic transitions that would satisfy Franck–Condon principle. Absorption spectra closely harmonize to experimental UV-Vis result. The model also reveals intra-chain electronic transitions to be the dominant absorption mechanism. All parameters of the model are obtained from either ab-initio Density Functional Theory (DFT) or Molecular Dynamics (MD) calculations, so that this model is capable of predicting charge transport and light absorption properties of new conjugated polymers without introducing fit parameters.
NONLINEAR CURRENT DENSITY IN QUANTUM WELLS WITH PARABOLIC POTENTIAL UNDER CROSSED ELECTRIC AND MAGNETIC FIELDS
Authors: HOI BUI DINH , PHONG TRAN CONG
Published: October 2012

The DC electrical transport in a quantum well (QW) with parabolic confinement potential [Formula: see text] (where m and ωz are the effective mass of electron and the confinement frequency in z direction, respectively) subjected to a crossed DC electric field and magnetic field, is studied theoretically. The scattering by optical phonons is taken into account at high temperatures and strong magnetic fields. We obtained the expression for nonlinear current density (NCD) involving external (electric and magnetic) fields and characteristic parameters of QW. The dependence of NCD on the DC electric field is complicated. The analytical result is computationally evaluated and graphically plotted for a specific parabolic QW of GaAs / AlGaAs . The numerical results show the appearance of maximum peaks satisfying the condition of intersubband magnetophonon resonance (MPR) effect in the presence of a DC electric field. Especially, we show that the effect can be applied in experiment to determine some physical parameters by using magnetic field, such as the numbers of Landau levels for which electrons transfer, the effective mass, the charge of electrons or the confinement frequency characterized for PQW.
Study of SF6/N2O Microwave Plasma for Surface Texturing of Multicrystalline (<150 µm) Solar Substrates
Authors: Chan Boon Teik , Kunnen Eddy , Uhlig Matthias , Marneffe Jean-Francois de , Xu Kaidong , Boullart Werner , Rau Bernd , Poortmans Jef
Published: October 2012

Surface texturing is an imperative process to reduce the reflection of the incident light on solar cells, by enhancing sunlight diffusion into the silicon solar cells for photon generation. As a result, the current generation can be increased. In this study, the plasma texturing process with linear microwave plasma sources has been benchmarked with the industrial acidic iso-texturing process on 156×156 mm2 multicrystalline substrates. By optimizing the plasma texturing parameters, the absolute solar cells efficiency can be increased by 4.9% for 150 µm thickness silicon substrate. The proposed process offers a significant advantage over the standard acidic iso-texturing without major modification in the existing industrial solar cells manufacturing sequence. In order to explain plasma-induced surface morphology changes, the Kardar–Parisi–Zhang (KPZ), Pétri–Brault, and Jason–Drotar models are used.
The Emitter Having Microcrystalline Surface in Silicon Heterojunction Interdigitated Back Contact Solar Cells
Authors: Ji Kwang-sun , Syn Hojung , Choi Junghoon , Lee Heon-Min , Kim Donghwan
Published: October 2012

In producing the Si heterojunction interdigitated backcontact solar cells, we investigated the feasibility of applying amorphous Si emitter having considerable crystalline Si phase at the facing to transparent conducting oxide (TCO) layer. Prior to evaluating electrical property, we characterized material nature of hydrogenated microcrystalline p-type silicon (µc-p-Si:H) as crystallized fraction, surface morphology, bonding kinds in thin films and then surface passivation quality finally. The diode and interface contact characteristics were induced by the simple test device and then current–voltage (I–V) curve showed more linearity in µc/hydrogenated amorphous silicon (a-Si:H) emitter case. We fabricated heterojunction back contact (HBC) solar cells using p/n interdigitated structure and acquired the 23.4% efficiency in cell size with performance parameters as open-circuit voltage (V
oc) 723 mV, short-circuit current density (J
sc) 41.8 mA/cm2, fill factor (FF) 0.774, in the cell size (at 2×2 cm2).
Record Efficiency on Large Area P-Type Czochralski Silicon Substrates
Authors: Hallam Brett , Wenham Stuart , Lee Haeseok , Lee Eunjoo , Lee Hyunwoo , Kim Jisun , Shin Jeongeun , Cho Kyeongyeon , Kim Jisoo
Published: October 2012

In this work we report a world record independently confirmed efficiency of 19.4% for a large area p-type Czochralski grown solar cell fabricated with a full area aluminium back surface field. This is achieved using the laser doped selective emitter solar cell technology on an industrial screen print production line with the addition of laser doping and light induced plating equipment. The use of a modified diffusion process is explored in which the emitter is diffused to a sheet resistance of 90 Ω/□ and subsequent etch back of the emitter to 120 Ω/□. This results in a lower surface concentration of phosphorus compared to that of emitters diffused directly to 120 Ω/□. This modified diffusion process subsequently reduces the conductivity of the surface in relation to that of the heavily diffused laser doped contacts and avoids parasitic plating, resulting an average absolute increase in efficiency of 0.4% compared to cells fabricated without an emitter etch back process.
Industrial 6 Inch Multicrystalline Silicon Solar Cells Fabricated Using Reactive Ion Etching with Efficiency Exceeding 18%
Authors: Shim Ji-Myung , Lee Hyun-Woo , Cho Kyeong-Yeon , Lee Eun-Joo , Kim Ji-Soo , Kong Ji-Hyun , Jo Soo-Jeong , Kim Ji-Sun , Lee Hae-Seok
Published: October 2012

To obtain a lower reflectance, we applied a maskless plasma texturing technique by reactive ion etching (RIE) to acid-textured multicrystalline silicon (mc-Si) wafer. RIE texturing produced a deep and narrow textured surface with an excellent low reflectance. Owing to plasma-induced damage, unless the RIE-textured surface is subjected to proper damage removal etching (DRE), it shows drops in open circuit voltage (V
oc) and fill factor (FF). RIE-textured samples with proper DRE showed sufficiently higher short circuit current (I
sc) than acid-textured samples without a drop in V
oc. In this study, we applied RIE texturing under optimized DRE condition to the selective emitter structure. In comparison with the acid-textured solar cells, RIE-textured solar cells have absolute gains in I
sc above 200 mA. We successfully fabricated a 6-in. mc-Si solar cell with a conversion efficiency exceeding 18% by applying selective emitter technology with RIE texturing.
A New Attempt at Alkaline Texturization of Monocrystaline Silicon with Anionic Surfactant as the Additive
Authors: Li Hailing , Wang Wenjing , Zhao Lei , Zhou Chunlan , Diao Hongwei
Published: October 2012

Owing to the volatilization of isopropanol (IPA), instability in the alkaline texturization of monocrystalline silicon has been a big problem for a long time. Many additives were adapted to replace IPA, such as high boiling point alcohols. In this experiment, as a new attempt, sodium lauryl sulfate (SDS), a type of anionic surfactant, was used as the additive in NaOH solution. The etching properties of silicon in 2 wt % NaOH/15–30 mg/L SDS solution were analyzed. To improve the wettability of silicon, two types of metal salt, NaCl and Na2CO3 with concentration from 2 to 15 wt %, were applied to the 2 wt % NaOH/15 mg/L SDS solution. The results showed that the effect of NaCl was better than that of Na2CO3. Finally, the role of the additive was discussed.
Fundamental Properties of Titanium-Doped Indium Oxide and Its Application to Thin-Film Silicon Solar Cells
Authors: Sobajima Yasushi , Muto Hirotaka , Shinohara Yoshihiro , Sada Chitose , Matsuda Akihisa , Okamoto Hiroaki
Published: October 2012

We have investigated the fundamental optoelectronic properties of newly developed transparent conductive oxide (TCO) materials, e.g., titanium-doped indium oxide (InTiO). InTiO films, being deposited at 50 °C by the RF-magnetron-sputtering method followed by thermal annealing at 200 °C, show excellent optoelectronic properties for solar-cell application. We have demonstrated the improved photovoltaic performance of n–i–p microcrystalline-silicon (µc-Si:H) solar cells whose i layer is prepared at a high rate of 2.3 nm/s using a stacked structure of InTiO with aluminum-doped zinc oxide (AZO) as top (front) TCO layers.
Realization of Large-Domain Barium Disilicide Epitaxial Thin Film by Introduction of Miscut to Si(111) Substrate
Authors: Hara Kosuke O. , Usami Noritaka , Toh Katsuaki , Toko Kaoru , Suemasu Takashi
Published: October 2012

The domain structure of BaSi2 epitaxial films grown on vicinal Si(111) substrates has been studied in order to fabricate high-quality BaSi2 crystals with large domains. The X-ray pole figure measurement shows that the BaSi2 films grown on vicinal substrates as well as the on-axis substrate consist of three epitaxial variants which are equivalent in terms of 60° in-plane rotations, and that one of the variants is dominant in the film grown on the 2°-inclined substrate. The orientation maps produced by electron backscatter diffraction show that the domains with the b axis parallel to the miscut direction are larger than the others in the film grown on the 2°-inclined substrate, while the domain sizes of three variants are found similar in the films grown on the on-axis and 4°-inclined substrates. The possible origin of the large domain formation is discussed with the focus on the initial growth stage observed by atomic force microscopy. Nucleation from the step edge is proposed as the mechanism of the large-domain formation considering the lattice matching to the step edge, while nucleation is suggested to occur at the terrace edges on the 4°-inclined substrate.
Analysis of Optical and Morphological Properties of Aluminium Induced Texture Glass Superstrates
Authors: Wang Juan , Venkataraj Selvaraj , Battaglia Corsin , Vayalakkara Premachandran , Aberle Armin G.
Published: October 2012

Texturing the glass surface is a promising method for improving the light trapping properties of superstrate thin-film silicon solar cells, as it enables thinner absorber layers and, possibly, higher cell efficiencies. In this paper we present the optical and morphological properties of borosilicate glass superstrates textured with the aluminium induced texture (AIT) method. High haze values are achieved without any reduction in the total optical transmission of the glass sheets after the AIT process. Scanning electron microscope and atomic force microscope (AFM) measurements reveal a laterally uniform surface morphology of the AIT texture. We demonstrate that the surface roughness and thus the transmission haze can be controlled by adjusting the AIT process parameters. From the AFM images, we extract histograms of the local height and angle distributions of the texture. Samples with a wide angle distribution are shown to produce the highest optical haze. The results of this analysis provide a better understanding of the correlation between the AIT process parameters and the resulting surface morphology. This analysis is further extended to an amorphous silicon pin solar cell deposited onto the textured glass substrate.