bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal resource partitioning and climatological influences on colony flight and foraging of stingless bees (Apidae; Meliponini) in Ugandan tropical forests
Authors: Kajobe Robert , Echazarreta Carlos M.
Published: November 2005

We studied the flight activity of two stingless bee species (Meliponula ferruginea and Meliponula nebulata) and the environmental factors influencing their flight. Two morphs of M. ferruginea were studied: M. ferruginea (brown) in Budongo forest and M. ferruginea (black) in Bwindi Park. The two bee species exited their nests in characteristically distinct foraging bouts suggesting that the recruitment methods used may be direct leading or ‘piloting’. The number of individuals in a returning bout was less than that in an exiting bout suggesting recruits do not follow experienced foragers the whole distance to food source, a phenomenon referred to as ‘partial piloting’. Flight period of M. ferruginea (black) and M. nebulata in Bwindi was restricted to a few hours each day. Meliponula nebulata foraged in the drizzle; a survival strategy, which could promote its reproductive fitness. Nectar and pollen foraging took place throughout the day while the removal of debris was greater in the late hours of the morning. Increased temperature resulted in significant increase in number of exiting bees. There was increase in number of exiting bees with decrease in humidity up to an optimal of 78% thereafter, increase in humidity resulted in reduced number of exiting bees.
The essential GTPase RbgA (YlqF) is required for 50S ribosome assembly in Bacillus subtilis
Authors: Uicker William C. , Schaefer Laura , Britton Robert A.
Published: November 2005

In this paper the essential GTPase YlqF is shown to participate in the biogenesis of the 50S ribosomal subunit in Bacillus subtilis. Cells depleted of YlqF displayed gene expression profiles and nucleoid morphologies that were consistent with a function for YlqF in translation. In addition, YlqF is evolutionarily linked to two eukaryotic GTPases, Nog2p and Nug1p, that are involved in the biogenesis and the nuclear export of the 60S ribosomal subunit. Analysis of ribosomes from cells depleted of YlqF demonstrated that the formation of 70S ribosomes was greatly reduced and the large subunit sedimented at 45S. Cells grown with varying depleted levels of YlqF, yielding doubling times ranging from 38 min to 150 min, all displayed the 45S intermediate. Purified YlqF‐His6 protein associates with the 45S intermediate, but not the mature 50S subunit in vitro. Analysis of proteins from the 45S intermediate indicated that ribosomal protein L16, which is added late during in vitro Escherichia coli 50S ribosome biogenesis, was missing from the 45S intermediate. These results support a model in which YlqF participates in the formation of active 70S ribosomes in the cell by functioning in a late step of 50S subunit biogenesis. Based on these results we propose to rename the ylqF gene rbgA (ribosome biogenesis GTPase A).
House cleaning, a part of good housekeeping
Authors: Galperin Michael Y. , Moroz Olga V. , Wilson Keith S. , Murzin Alexey G.
Published: November 2005

Cellular metabolism constantly generates by‐products that are wasteful or even harmful. Such compounds are excreted from the cell or are removed through hydrolysis to normal cellular metabolites by various ‘house‐cleaning’ enzymes. Some of the most important contaminants are non‐canonical nucleoside triphosphates (NTPs) whose incorporation into the nascent DNA leads to increased mutagenesis and DNA damage. Enzymes intercepting abnormal NTPs from incorporation by DNA polymerases work in parallel with DNA repair enzymes that remove lesions produced by modified nucleotides. House‐cleaning NTP pyrophosphatases targeting non‐canonical NTPs belong to at least four structural superfamilies: MutT‐related (Nudix) hydrolases, dUTPase, ITPase (Maf/HAM1) and all‐α NTP pyrophosphatases (MazG). These enzymes have high affinity (Km's in the micromolar range) for their natural substrates (8‐oxo‐dGTP, dUTP, dITP, 2‐oxo‐dATP), which allows them to select these substrates from a mixture containing a ∼1000‐fold excess of canonical NTPs. To date, many house‐cleaning NTPases have been identified only on the basis of their side activity towards canonical NTPs and NDP derivatives. Integration of growing structural and biochemical data on these superfamilies suggests that their new family members cleanse the nucleotide pool of the products of oxidative damage and inappropriate methylation. House‐cleaning enzymes, such as 6‐phosphogluconolactonase, are also part of normal intermediary metabolism. Genomic data suggest that house‐cleaning systems are more abundant than previously thought and include numerous analogous enzymes with overlapping functions. We discuss the structural diversity of these enzymes, their phylogenetic distribution, substrate specificity and the problem of identifying their true substrates.
Rac1 and Cdc42 regulate hyphal growth and cytokinesis in the dimorphic fungus Ustilago maydis
Authors: Mahlert Michael , Leveleki Leonora , Hlubek Andrea , Sandrock Björn , Bölker Michael
Published: November 2005

Small GTP‐binding proteins of the highly conserved Rho family act as molecular switches regulating cell signalling, cytoskeletal organization and vesicle trafficking in eukaryotic cells. Here we show that in the dimorphic plant pathogenic fungus Ustilago maydis deletion of either cdc42 or rac1 results in loss of virulence but does not interfere with viability. Cells deleted for cdc42 display a cell separation defect during budding. We have previously shown that the Rho‐specific guanine nucleotide exchange factor (GEF) Don1 is required for cell separation in U. maydis. Expression of constitutive active Cdc42 rescues the phenotype of don1 mutant cells indicating that Don1 triggers cell separation by activating Cdc42. Deletion of rac1 affects cellular morphology and interferes with hyphal growth, whereas overexpression of wild‐type Rac1 induces filament formation in haploid cells. This indicates that Rac1 is both necessary and sufficient for the dimorphic switch from budding to hyphal growth. Cdc42 and Rac1 share at least one common essential function because depletion of both Rac1 and Cdc42 is lethal. Expression of constitutively active Rac1Q61L is lethal and results in swollen cells with a large vacuole. The morphological phenotype, but not lethality is suppressed in cla4 mutant cells suggesting that the PAK family kinase Cla4 acts as a downstream effector of Rac1.
The GATA factor AreA regulates localization and in vivo binding site occupancy of the nitrate activator NirA
Authors: Berger Harald , Pachlinger Robert , Morozov Igor , Goller Sabine , Narendja Frank , Caddick Mark , Strauss Joseph
Published: November 2005

The GATA factor AreA is a wide‐domain regulator in Aspergillus nidulans with transcriptional activation and chromatin remodelling functions. AreA interacts with the nitrate‐specific Zn2‐C6 cluster protein NirA and both proteins cooperate to synergistically activate nitrate‐responsive genes. We have previously established that NirA in vivo DNA binding site occupancy is AreA dependent and in this report we provide a mechanistic explanation for our previous findings. We now show that AreA regulates NirA at two levels: (i) through the regulation of nitrate transporters, AreA affects indirectly the subcellular distribution of NirA which rapidly accumulates in the nucleus following induction; (ii) AreA directly stimulates NirA in vivo target DNA occupancy and does not act indirectly by chromatin remodelling. Simultaneous overexpression of NirA and the nitrate transporter CrnA bypasses the AreA requirement for NirA binding, permits utilization of nitrate and nitrite as sole N‐sources in an areA null strain and leads to an AreA‐independent nucleosome loss of positioning.
Playground safety in South Western Sydney
Authors: Martin J , Cooper CD
Published: November 2005

Objective: Recognition of the cost of injuries sustained in playgrounds has led to the development of Australian/New Zealand Standards for playground safety. This study assesses compliance of public playgrounds in South Western Sydney with the current Standards.

Methods: Playgrounds in South Western Sydney were randomly audited for compliance with Australian/New Zealand Standards for playground equipment pertaining to fall height, type of undersurface material, adequacy of maintenance of undersurface materials and adequacy of the safe fall zone. Comparisons were made with an audit of playgrounds in New South Wales undertaken in 1995 by Kidsafe.

Results: Of the 257 pieces of equipment from 87 playgrounds audited, only three (3.4%) playgrounds and 65 (25.3%) pieces of equipment complied with all criteria assessed. Compared with the 1995 study, there has been a significant improvement in equipment complying with height standards (84.4% vs 72.2%, P < 0.0001) and appropriate undersurface material (66.8% vs 45.4%, P < 0.0001). Pinebark is now the most common appropriate undersurface material used but is poorly maintained, particularly in high‐traffic areas. Of 131 pieces of equipment with an appropriate undersurface material, only 38 (29%) had an adequate safe fall zone.

Conclusions: Improvements in playground safety have occurred; however, very few playgrounds meet the Australian/New Zealand Standards. Compliance with Standards pertaining to maintenance of undersurface materials and safe fall zone is poor. Mechanisms need to be developed to support councils in the upgrading and maintenance of existing playgrounds.
Prospective audit of treatment of paediatric febrile neutropenia in Australasia
Authors: Chamberlain JD , Smibert E , Skeen J , Alvaro F
Published: November 2005

Objectives: Febrile neutropenia post‐chemotherapy continues to impose a burden of morbidity and mortality on patients and families affected by childhood cancer, whereas these unplanned hospital admissions increase the financial cost of treating paediatric malignancies. There are currently no published national guidelines. This study comprises the first audit of current therapeutic practice in Australasia.

Methods: Information was sought prospectively from the 12 paediatric oncology tertiary referral centres in Australia and New Zealand regarding treatment of febrile neutropenia episodes commencing between 11 March and 10 May 2002.

Results: Data were returned on 127 episodes by nine centres. The median length of stay was 6 days and 18 different antibiotic regimens were implemented as first‐line therapy. The median neutrophil count at the beginning and end of the febrile neutropenic episode was 0.0 × 109/L (range 0.0 to 2.3 × 109/L) and 0.7 × 109/L (range 0.0 to 25.4 × 109/L), respectively. Thirty per cent of episodes had positive blood cultures. Of these, 81% occurred in patients with tunnelled central venous catheters. The initial antimicrobial combination was changed in 61% of episodes. Outpatient antibiotics were used in 21% episodes after initial intravenous antimicrobial therapy.

Conclusions: The current practice in Australasia is consistent with international guidelines, although changes are made more frequently to first‐line therapy than in previous published studies. The central venous catheters are associated with a much higher risk of bacteraemia and consideration should be given to increased use of implanted port systems.
Changes of urinary nerve growth factor and prostaglandins in male patients with overactive bladder symptom
Authors: KIM JOON CHUL , PARK EUN YOUNG , HONG SUNG HOO , SEO SEONG IL , PARK YONG HYUN , HWANG TAE‐KON
Published: November 2005

Abstract  Aim:  Nerve growth factor (NGF) and prostaglandins (PG) in the urinary bladder can be affected by pathology of bladder, and this change can be noted in the urine. This study was performed to investigate the changes in urinary NGF and PG in male patient with overactive bladder (OAB) symptoms.

Methods:  The study group included 75 male patients with OAB symptoms and 20 males without bladder symptoms as controls. Evaluation included history‐taking, urinalysis, International Prostate Symptom Score (IPSS) and urodynamic study. The NGF, PGE2, PGF2α and PGI2 levels in voided urine were analyzed by enzyme linked immunosorbent assay and these results were compared in control and OAB patients. Also, the urinary levels of NGF and PG were correlated with IPSS score and urodynamic parameters in OAB patients.

Results:  The urinary levels of NGF and PGE2 were signiﬁcantly increased in patients with OAB compared with control (P < 0.05). The urodynamic study in OAB patients showed that more than half of the patients had detrusor overactivity and bladder outlet obstruction. The incidence of detrusor underactivity was noted in seven patients in the OAB group. The urinary level of PGE2 was decreased in patients with detrusor underactivity compared with patients without detrusor underactivity (P < 0.05), and negatively correlated with maximum bladder capacity in OAB patients (P < 0.05).

Conclusions:  NGF and PG may have important role in male patients with OAB, and the urinary level of PGE2 can change according to detrusor function. Therefore, these results may be used as urinary markers to evaluate the OAB symptoms.
Acucise endopyelotomy: A technique with limited efﬁcacy for primary ureteropelvic junction obstruction in adults
Authors: WEIKERT STEFFEN , CHRISTOPH FRANK , MÜLLER MARKUS , SCHOSTAK MARTIN , MILLER KURT , SCHRADER MARK
Published: November 2005

Abstract  Aim:  To retrospectively evaluate the efﬁcacy of Acucise endopyelotomy in a series of patients with primary ureteropelvic junction obstruction (UPJO).

Methods:  Twenty‐four patients with a symptomatic primary UPJO underwent Acucise endopyelotomy. Patients with high‐grade hydronephrosis and/or poor renal function were excluded. Patients were followed by ultrasound imaging, intravenous urography, diuretic renography, and clinical review.

Results:  The overall success rate was 58% (14/24 patients), with a median follow up of 32 months. Of the ten patients in whom Acucise endopyelotomy failed, seven underwent open pyeloplasty, one required nephrectomy, and two received a permanent ureteral stent. A poor outcome was noted in patients without perioperative extravasation.

Conclusions:  Our experience with Acucise endopyelotomy indicates that the success rate is lower than initially reported. Larger studies are needed to clarify the role of Acucise endopyelotomy in comparison with other techniques.
Laparoscopic radical cystectomy with extracorporeal urinary diversion: Preliminary experience
Authors: HONG SUNG‐HOO , SEO SEONG‐IL , KIM JOON CHUL , HWANG TAE‐KON
Published: November 2005

Abstract  Aim:  We present our experience with the ﬁrst eight patients who underwent laparoscopic radical cystectomy with bilateral pelvic lymphadenectomy and extracorporeal urinary diversion. Patients, operative data and the surgical techniques are presented.

Methods:  Between June 2003 and April 2004, seven men and one woman with organ‐conﬁned muscle‐invasive transitional cell carcinoma of the bladder underwent laparoscopic radical cystectomy with urinary diversion. The age range was 41–73 years. Laparoscopic radical cystectomy and bilateral pelvic lymphadenectomy were performed using ﬁve ports by a transperitoneal approach. An ileal conduit diversion or ileal W‐neobladder was constructed through the site of specimen retrieval.

Results:  We performed eight radical cystectomies with ileal conduits (six cases) or orthotopic ileal W‐neobladders (two cases). Conversion to open surgery was necessary in one due to technical difﬁculty in urethroneobladder anastomosis. Mean operating time was 560 min (range 455–680). Mean estimated blood loss was 675 mL (range 400–1050). Two of the eight patients needed blood transfusion (800 mL each). Mean days to oral intake and ambulation was 4.4 (range 2–6) and 4.1 (range 3–5), respectively. Mean hospital stay was 12.8 days (range 7–28). Mean follow up was 6.1 months (range 4–14). Histopathological examination of the specimens revealed stage T2N0M0 in ﬁve cases, T3aN0M0 in one, T3aN1M0 in one and T3bN1M0 in one. No metastases have been detected and all are alive and free of disease.

Conclusion:  Laparoscopic radical cystectomy is feasible, although difﬁcult and technically demanding, and our results are promising. With more experience and improvement of the surgical technique, laparoscopic radical cystectomy with urinary diversion may become an alternative surgical method for treating the selected patients with localized muscle invasive bladder cancer.
Advanced renal pelvic carcinoma associated with dermatomyositis
Authors: SHINOHARA NOBUO , HARABAYASHI TORU , SUZUKI SHIN , NAKAMURA MICHIKO , ITOH TOMOO , NONOMURA KATSUYA
Published: November 2005

Abstract  Dermatomyositis is an uncommon inﬂammatory myopathy with characteristic cutaneous manifestations which is frequently linked to several cancers. A 42‐year‐old man presented with left ﬂank pain with typical symptoms of dermatomyositis. Computed tomography showed a solid mass in the pelvis of the left kidney and lymphadenopathy in the retroperitoneum. Since the general condition of the patient rapidly deteriorated because of marked muscle weakness of the respiratory muscles, the patient initially underwent medical treatment with prednisolone. After the improvement of respiratory function, the patient underwent radical nephroureterectomy and retroperitoneal lymphadenectomy. The pathological specimen showed moderately differentiated adenocarcinoma, stage pT3N2. After surgery, the patient showed a marked improvement of clinical symptoms related to dermatomyositis. Twenty‐two months later, multiple organ metastases occurred and the patient died of cancer. We should point out the signiﬁcance of surgical and medical treatment for these patients.
Real time ultrasound in laparoscopic bladder diverticulectomy
Authors: PORPIGLIA FRANCESCO , TERRONE CARLO , COSSU MARCO , RENARD JULIEN , GRANDE SUSANNA , SCARPA ROBERTO MARIO
Published: November 2005

Abstract  We describe our technique of laparoscopic diverticulectomy under ultrasound (US) guidance after a transurethral resection of prostate (TURP) in the treatment of patients with benign prostatic hyperplasia and bladder diverticulum. A standard TURP is performed with an Iglesias resectoscope. A 12‐Fr Foley catheter is positioned in the diverticulum and the catheter balloon is then inﬂated with 30 mL of water; then a Tiemann catheter is placed through the urethra into the bladder. A US probe is inserted through the 12 mm port placed in the right side by the surgeon, then laparoscopic transperitoneal bladder diverticulectomy is performed under US guidance. In our experience, the use of endolaparoscopic US makes identiﬁcation and dissection of the diverticulum easy, safe and effective, even when the procedure has to be performed in disadvantageous anatomic conditions such as lateral‐posterior diverticulum or post‐TURP imbibition of pelvic tissue.
Tubercular prostatic abscess as a complication of intravesical bacillus Calmette–Guérin immunotherapy
Authors: AUST THOMAS R. , MASSEY J ADRIAN
Published: November 2005

Abstract  We report a case of tubercular prostatic abscess in a patient who had undergone intravesical bacillus Calmette–Guérin immunotherapy for bladder carcinoma in situ. The abscess required surgical drainage and antituberculous treatment.
NMDA‐induced retinal injury is mediated by an endoplasmic reticulum stress‐related protein, CHOP/GADD153
Authors: Awai Maiko , Koga Takahisa , Inomata Yasuya , Oyadomari Seiichi , Gotoh Tomomi , Mori Masataka , Tanihara Hidenobu
Published: November 2005

We investigated the role of an endoplasmic reticulum stress‐associated protein, CHOP/GADD153, after NMDA‐induced mouse retinal damage. After injection of NMDA into the vitreous, TUNEL‐positive cells were detected in the retinal ganglion cell layer (GCL) and inner nuclear layer (INL) at 6 h after NMDA injection, and these gradually increased in number up to 24 h. Analysis by real‐time RT‐PCR revealed that CHOP mRNA was induced by about 3‐fold, at 2 h after NMDA injection. Immunoreactivity for the CHOP protein was intense in cells of the GCL following NMDA treatment. Immunoblot analysis showed that NMDA injection increased the expression of CHOP protein in the retina. Compared with wild‐type mice, CHOP–/– mice were more resistant to NMDA‐induced retinal cell death as determined by TUNEL assay. At 7 days after NMDA treatment, the thickness of the inner plexiform layer and INL were larger in CHOP–/– mice than in wild‐type mice. The number of residual cells in the GCL following NMDA treatment was significantly higher in CHOP–/– mice than in wild‐type mice. In conclusion, CHOP is induced in mouse retina by NMDA treatment, and CHOP–/– mice are more resistant to NMDA‐induced retinal damage, suggesting that CHOP plays an important role in NMDA‐induced retinal cell death.
The β‐amyloid peptide of Alzheimer's disease decreases adhesion of vascular smooth muscle cells to the basement membrane
Authors: Mok Su San , Losic Dusan , Barrow Colin J. , Turner Bradley J. , Masters Colin L. , Martin Lisandra L. , Small David H.
Published: November 2005

Cerebral amyloid angiopathy (CAA) is a major feature of Alzheimer's disease pathology. In CAA, degeneration of vascular smooth muscle cells (VSMCs) occurs close to regions of the basement membrane where the amyloid protein (Aβ) builds up. In this study, the possibility that Aβ disrupts adhesive interactions between VSMCs and the basement membrane was examined. VSMCs were cultured on a commercial basement membrane substrate (Matrigel). The presence of Aβ in the Matrigel decreased cell‐substrate adhesion and cell viability. Full‐length oligomeric Aβ was required for the effect, as N‐ and C‐terminally truncated peptide analogues did not inhibit adhesion. Aβ that was fluorescently labelled at the N‐terminus (fluo‐Aβ) bound to Matrigel as well as to the basement membrane heparan sulfate proteoglycan (HSPG) perlecan and laminin. Adhesion of VSMCs to perlecan or laminin was decreased by Aβ. As perlecan influences VSMC viability through the extracellular signal‐regulated kinase (ERK)1/2 signalling pathway, the effect of Aβ1–40 on ERK1/2 phosphorylation was examined. The level of phospho‐ERK1/2 was decreased in cells following Aβ treatment. An inhibitor of ERK1/2 phosphorylation enhanced the effect of Aβ on cell adhesion. The studies suggest that Aβ can decrease VSMC viability by disrupting VSMC–extracellular matrix (ECM) adhesion.
Isolation and multiplex analysis of six polymorphic microsatellites in the Antarctic notothenioid fish, Trematomus newnesi
Authors: VAN HOUDT J. K. J. , HELLEMANS B. , VAN DE PUTTE A. , KOUBBI P. , VOLCKAERT F. A. M.
Published: November 2005

Six polymorphic microsatellites were isolated from the dusky notothen, Trematomus newnesi (Boulenger 1902), using a microsatellite enrichment protocol and selective hybridization with di‐ tetra‐ and penta‐repeat probes. The loci were screened in 48 individuals captured in the Southern Ocean (coastal zone of Terre‐Adélie), revealing eight to 22 alleles per locus and an observed heterozygosity ranging from 0.70 to 0.92. These microsatellite markers provide a tool to study the relationship between the various morphs observed in this species and can be used for population genetic analysis and biodiversity studies.
Development of DNA microsatellite markers in tropical yam (Dioscorea sp.)
Authors: TOSTAIN S. , SCARCELLI N. , BROTTIER P. , MARCHAND J.‐L. , PHAM J.‐L. , NOYER J.‐L.
Published: November 2005

We developed new simple sequence repeat (SSR) markers in different species of yam (Dioscorea sp.). A microsatellite‐enriched bank was created from Dioscorea alata, Dioscorea abyssinica and Dioscorea praehensilis. Sixteen polymorphic loci were characterized. Several of these markers are transferable to species of other Dioscorea sections.
Isolation and characterization of microsatellite loci in the icefish Chionodraco rastrospinosus (Perciformes, Notothenioidea, Channichthyidae)
Authors: PAPETTI CHIARA , ZANE LORENZO , PATARNELLO TOMASO
Published: November 2005

We characterized eight polymorphic microsatellites in the icefish Chionodraco rastrospinosus (Perciformes, Notothenioidea, Channichthyidae). Microsatellites were isolated from a partial genomic library enriched for an AC motif. Chionodraco rastrospinosus is an endemic species inhabiting southern ocean waters surrounding the Antarctic Peninsula, the South Shetland Islands, and the South Orkney Islands. An excess of homozygotes was observed in seven out of the eight investigated loci; however, presence of null alleles was detected only for three of them suggesting that other factors may act in reducing heterozygosity. These molecular markers will be useful to investigate icefish genetic structure, possibly providing insights on its effective population size and demographic history.
Association of kinesin and myosin with pigment granules in crustacean chromatophores
Authors: Boyle Robert Tew , McNamara John Campbell
Published: November 2005

Chromatic adaptation in crustaceans results from the differential distribution of colored pigment granules within their chromatophores consequent to cell signaling by neurosecretory peptides. However, the force transducing, mechanochemical protein motors responsible for granule translocation, and their molecular mechanisms of action, are not well understood. The present study uses immunocytochemical techniques and a motility assay in vitro to demonstrate that protein motors from the kinesin and myosin superfamilies are stably associated with membrane‐bounded pigment granules in the red, ovarian chromatophores of the freshwater, palaemonid shrimp, Macrobrachium olfersii. Monoclonal antibodies against conventional kinesin heavy chain, and an anti‐myosin whole serum, labeled pigment‐containing fragments prepared from homogenates of chromatophores with fully dispersed or aggregated pigments: this finding infers a permanent association between the protein motors and the pigment granules, and suggests that such motors may be regulated while bound to their cargos. The pigment aggregator appears to be a myosin since the anti‐myosin whole serum attenuated hormonally triggered pigment aggregation in the motility assay in vitro, and induced pigment hyper‐dispersion in some chromatophores. Western blots of the chromatophore‐containing, ovarian tissue homogenate demonstrated protein bands consistent with myosin II and myosin XII, either of which may be the pigment aggregator. This study provides the first direct evidence for myosin and kinesin protein motors directly and stably associated with pigment granules in crustacean chromatophores, and may represent the first successful isolation of myosin class XII.
Apaf‐1 expression in human cutaneous melanoma progression and in pigmented nevi
Authors: Niedojadło Katarzyna , Łabędzka Karolina , Łada Ewelina , Milewska Agnieszka , Chwirot Barbara W.
Published: November 2005

Malignant melanoma is notoriously refractive to therapy and resistant to apoptosis. This may reflect the downregulation of Apaf‐1, an important mediator of mitochondrial‐dependent apoptosis, observed in vitro in melanoma cell lines and by immunohistochemistry for Apaf‐1 protein in histological samples of primary and metastatic melanomas. Although it has been suggested that loss of Apaf‐1 expression may be an indicator of malignant transformation in melanoma, previous studies on Apaf‐1 expression in benign pigmented nevi were performed without reference to their histologic type. Here we have evaluated the expression of Apaf‐1 mRNA by fluorescence in situ hybridization and of Apaf‐1 protein by immunohistochemistry in a large panel of human melanomas and in eight types of pigmented nevi, considered potential precursors for cutaneous melanoma. We observe a strong negative correlation between melanoma progression assessed according to Clark classification and the expression of Apaf‐1. A significant decrease in Apaf‐1 expression was observed between Clark II and Clark III lesions, the stages usually associated with a transition from horizontal to vertical growth phase of melanoma. There was also statistically significant difference in Apaf‐1 mRNA expression between melanomas of Breslow thickness <1 mm and >4 mm. No Apaf‐1 expression could be detected in lymph node melanoma metastases. These results suggest that Apaf‐1 expression may become a prognostic marker for progress of human cutaneous melanoma and further support the notion that loss of Apaf‐1 may be an important contributory factor in the development of the disease.
Female receptivity phenotype of icebox mutants caused by a mutation in the L1‐type cell adhesion molecule neuroglian
Authors: Carhan A. , Allen F. , Armstrong J. D. , Goodwin S. F. , O'Dell K. M. C.
Published: November 2005

Relatively little is known about the genes and brain structures that enable virgin female Drosophila to make the decision to mate or not. Classical genetic approaches have identified several mutant females that have a reluctance‐to‐mate phenotype, but most of these have additional behavioral defects. However, the icebox (ibx) mutation was previously reported to lower the sexual receptivity of females, without apparently affecting any other aspect of female behavior. We have shown that the ibx mutation maps to the 7F region of the Drosophila X chromosome to form a complex complementation group with both lethal and viable alleles of neuroglian (nrg). The L1‐type cell adhesion molecule encoded by nrg consists of six immunoglobulin‐like domains, five fibronectin‐like domains, one transmembrane domain and one alternatively spliced intracellular domain. The ibx strain has a missense mutation causing a glycine‐to‐arginine change at amino acid 92 in the first immunoglobulin domain of nrg. Defects in the central brain of ibx mutants are similar to those observed in another nrg mutant, central brain deranged1 (ceb1). However, both ceb1 homozygous and ceb1/ibx heterozygous females are receptive. The expression of a transgene containing the non‐neural isoform of nrg rescues both the receptivity and the brain structure phenotypes of ibx females.
Behavioral and sleep/wake characteristics of mice lacking norepinephrine and hypocretin
Authors: Hunsley M. S. , Curtis W. R. , Palmiter R. D.
Published: November 2005

We investigated the interaction between norepinephrine (NE) and orexin/hypocretin (Hcrt) in the control of sleep behavior and narcoleptic symptoms by creating mice that were deficient in both neurotransmitters. Mice with a targeted disruption of the dopamine β‐hydroxylase (Dbh) gene (deficient in NE and epinephrine) or the Hcrt gene were bred to generate double knockouts (DKOs), each single KO (Dbh‐KO and Hcrt‐KO), and control mice. The duration of wake, non‐rapid eye movement (NREM) and REM sleep were monitored by electroencephalogram (EEG)/electromyogram (EMG) recording over a 24‐h period, and the occurrence of behavioral arrests was monitored by video/EEG recording for 4 h. Overall, there was very little interaction between the two genes; for most parameters that were measured, the DKO mice resembled either Dbh‐KO or Hcrt‐KO mice. REM sleep was increased in both DKO and Hcrt‐KO mice at night relative to the other groups, but DKO mice had significantly more REM sleep during the day than the other three groups. Sleep latency in response to saline or amphetamine injections was reduced in Dbh‐KO and DKO mice relative to other groups. Behavioral arrests, that are frequent in Hcrt‐KO mice, were not exacerbated in DKO mice.
Novel approach to the behavioural characterization of inbred mice: automated home cage observations
Authors: De Visser L. , Van Den Bos R. , Kuurman W. W. , Kas M. J. H. , Spruijt B. M.
Published: November 2005

Here we present a newly developed tool for continuous recordings and analysis of novelty‐induced and baseline behaviour of mice in a home cage‐like environment. Aim of this study was to demonstrate the strength of this method by characterizing four inbred strains of mice, C57BL/6, DBA/2, C3H and 129S2/Sv, on locomotor activity. Strains differed in circadian rhythmicity, novelty‐induced activity and the time–course of specific behavioural elements. For instance, C57BL/6 and DBA/2 mice showed a much faster decrease in activity over time than C3H and 129S2/Sv mice. Principal component analysis revealed two major factors within locomotor activity, which were defined as ‘level of activity’ and ‘velocity/stops’. These factors were able to distinguish strains. Interestingly, mice that displayed high levels of activity in the initial phase of the home cage test were also highly active during an open‐field test. Velocity and the number of stops during movement correlated positively with anxiety‐related behaviour in the elevated plus maze. The use of an automated home cage observation system yields temporal changes in elements of locomotor activity with an advanced level of spatial resolution. Moreover, it avoids the confounding influence of human intervention and saves time‐consuming human observations.
Reactive magnetron sputtering of hard Si–B–C–N films with a high-temperature oxidation resistance
Authors: Vlček Jaroslav , Potocký Štěpán , Čížek Jiří , Houška Jiří , Kormunda Martin , Zeman Petr , Peřina Vratislav , Zemek Josef , Setsuhara Yuichi , Konuma Seiji
Published: November 2005

Based on the results obtained for C–N and Si–C–N films, a systematic investigation of reactive magnetron sputtering of hard quaternary Si–B–C–N materials has been carried out. The Si–B–C–N films were deposited on p-type Si(100) substrates by dc magnetron co-sputtering using a single C–Si–B target (at a fixed 20% boron fraction in the target erosion area) in nitrogen-argon gas mixtures. Elemental compositions of the films, their surface bonding structure and mechanical properties, together with their oxidation resistance in air, were controlled by the Si fraction (5–75%) in the magnetron target erosion area, the Ar fraction (0–75%) in the gas mixture, the rf induced negative substrate bias voltage (from a floating potential to −500V) and the substrate temperature (180–350°C). The total pressure and the discharge current on the magnetron target were held constant at 0.5Pa and 1A, respectively. The energy and flux of ions bombarding the growing films were determined on the basis of the discharge characteristics measured for the rf discharge dominating in the deposition zone. Mass spectroscopy was used to show composition of the total ion fluxes onto the substrate and to explain differences between sputtering of carbon, silicon and boron from a composed target in nitrogen-argon discharges. The films, typically 1.0–2.4μm thick, possessing a density around 2.4gcm−3, were found to be amorphous in nanostructure with a very smooth surface (Ra⩽0.8nm) and good adhesion to substrates at a low compressive stress (1.0–1.6GPa). They exhibited high hardness (up to 47GPa) and elastic recovery (up to 88%), and extremely high oxidation resistance in air at elevated temperatures (up to a 1350°C substrate limit).
On the origin of a-type threading dislocations in GaN layers
Authors: Kwon Y. B. , Je J. H. , Ruterana P. , Nouet G.
Published: November 2005

The origin of threading dislocations (TDs) in GaN epitaxial layers grown on sapphire (0001) substrate is investigated using moiré fringes from plan-view transmission electron microscopy. The studied samples are nucleation layers deposited at 560°C for times ranging from 20sto180s. This initial stage growth gives rise to islands which are randomly rotated and relaxed with misfit dislocations. The islands that start to coalesce from 60s growth time keep this random orientation and this leads to the bending of 60° misfit dislocations in the interface plane to form a-type TDs inside low angle boundaries.
Silicon etch by fluorocarbon and argon plasmas in the presence of fluorocarbon films
Authors: Végh Joseph J. , Humbird David , Graves David B.
Published: November 2005

Molecular dynamics simulations have been conducted to study the mechanisms of silicon etch in the presence of fluorocarbon species (CF and C4F4), F atoms and Ar+ ions. The specific goal of the study was to find conditions in which steady Si etching occurs in the presence of a fluorocarbon (FC) film. Results indicate that if incident species are not properly chosen for the simulation, either steady etching is observed with no FC film present, or a FC film is present (often continuously growing in thickness) with no steady etching of the underlying film. With the proper set of incident species, C∕F ratio, neutral/ion flux ratio, and ion energy, we observed steady Si etching in the presence of a steady FC film. We also observed that the thicker the FC film, the lower the etch yield. A sufficiently thick film results in no etching and a continuous deposition. Simulation results are in qualitative agreement with analogous experimental measurements. The key is to find FC species that will stick with a high probability, forming a relatively open and porous film. In addition, our results suggest that this film will fluctuate in thickness from impact to impact, resulting in better transport of incident F and SiFx species, to and from the underlying Si, respectively. Steady state etching appears unlikely if the overlying FC film has the hard, dense, cross-linked character of films deposited from energetic fluorocarbon species. The basic mechanisms of etching, and the composition and depth of the underlying layers appear to be largely unaffected by the presence of the FC film. We have found ion energy deposition at a range of depths to be crucially important in the creation and transport of etch products. Ion energy deposition, ion-induced mixing, and reaction promotion are the key processes in all of the ion-assisted processes simulated, including the present case of etching in the presence of FC film. The FC film retards etching by slowing the rate at which etchants (e.g., F) reach the underlying film and the rate at which etch products leave. If the film is sufficiently thick or dense, etching will cease.
Optical properties of La-based high-K dielectric films
Authors: Cicerrella E. , Freeouf J. L. , Edge L. F. , Schlom D. G. , Heeg T. , Schubert J. , Chambers S. A.
Published: November 2005

We have characterized thin films of LaScO3 and LaAlO3 which were grown by molecular beam deposition on Si substrates. Samples of LaScO3 were also grown by pulsed laser deposition on MgO substrates. Using transmission studies between 1.5 and 6eV, we have established that low temperature deposition leads to a reduced band gap with respect to the bulk crystal. Furthermore, using spectroscopic ellipsometry from 5to9eV we observe substantial differences in near-band gap absorption between thin and thicker films for both materials. We obtain a band gap of 5.84eV for the thinner film of LaAlO3, whereas we find a band gap of 6.33eV for the thicker film of LaAlO3. Similarly we find band gaps of 5.5 and 5.96eV, respectively, for thin and thick films of LaScO3.
Simple method for estimating and comparing x-ray damage rates
Authors: Baer D. R. , Engelhard M. H. , Lea A. S. , Saraf L. V.
Published: November 2005

In this note we describe an approach for estimating and comparing rates or thresholds for x-ray-induced specimen damage during surface analysis. The method uses a common reference material to compare x-ray damage rates reported in the literature and in publications to the rates of damage that may occur on a specific instrument. Although the method makes several assumptions that are only partially valid, results from a few damage datasets appear acceptably consistent when comparing estimates to a time for 10% damage or signal change.
Quantitative analysis of sputter processes in a small magnetron system
Authors: Knittel Ivo , Gothe Marc , Hartmann Uwe
Published: November 2005

Sputter deposition of titanium in argon from a small circular magnetron is characterized. The dependence of the deposition rate on pressure, power, and target–substrate distance has been measured. A framework for the application of the analytic approach by Keller and Simmons of ballistic and diffusive transport to simple three-dimensional sputter geometries is developed and applied. The sputter yield and the pressure–distance product are determined from the data set as the only fit parameters of the model. For the entire range of operation of the magnetron, the sputter process can be described in terms of the relatively simple approach.
Preparation of bead metal single crystals by electron beam heating
Authors: Voigtländer Bert , Linke Udo , Stollwerk H. , Brona J.
Published: November 2005

For the fabrication of small metal bead crystals a gas flame is used to melt a wire forming a liquid droplet which solidifies upon cooling into a single crystal metal bead. Due to oxidation under ambient conditions bead crystals can be formed only from noble metals using this method. Here we describe a method how to fabricate bead crystals from a wide variety of metals and metal alloys (Cu, Mo, Ru, Rh, Pd, Ag, Ta, W, Re, Ir, Pt, Au, PtPd, Pd80Pt20, PtRh, AuAg, and PtIr) by electron beam heating under vacuum conditions. Narrow x-ray diffraction peaks confirm a high crystal quality of the bead crystals.
Effect of blade-surface-roughness on the pumping performance of a turbomolecular pump
Authors: Sawada T. , Yabuki M. , Sugiyama W. , Watanabe M.
Published: November 2005

Turbomolecular pumps (TMPs) are widely used in the semiconductor and other thin film industries. Some semiconductor processes form corrosive gases such as HCl or HF as byproducts. The elements of a TMP are sometimes coated with ceramic (SiO2) film for the purpose of preventing corrosion of the TMP. The blades coated with SiO2 have relatively rough surfaces. The effect of the surface roughness of the blades on the pumping performance has been studied experimentally and theoretically. Experimental results for TMPs with two rotor disks and one stator disk show that the TMP coated with SiO2 film gives about 11% to 13% higher maximum-compression ratio than the noncoated TMP when the blade speed ratio is 0.47. The theory based on the conic peak/dimple-surface-roughness model that has been proposed by the authors explains the change in the compression ratio with the surface roughness shown in the experiment.
Application of a Matsumoto-Ohtsuka-type vacuum flange to beam ducts for future accelerators
Authors: Suetsugu Y. , Shirai M. , Ohtsuka M.
Published: November 2005

The Matsumoto-Ohtsuka (MO)-type vacuum flange, which can provide a gapless connection and a highly reliable electric contact between flanges, was studied experimentally for a possible application to beam ducts for high-current accelerators, where the apertures have a complicated structure, such as the combination of a beam channel and one or two flat rectangular antechambers. In spite of the complex aperture, test flanges showed a good vacuum-sealing property. Vacuum sealing was successfully achieved with a reasonable fastening torque (15–20Nm), and remained sealed after baking at 250°C for 24h. A twist between flanges of up to about 5mrad was also manageable. A pseudoelastic structural analysis well reproduced the observed deformation of the flange. This analysis should be available for optimizing the flange structure. The MO-type vacuum flange was found to be promising for connecting flanges of the beam duct with a complicated aperture in future accelerators. The flange will also be available as a compact vacuum flange in cases where a complex aperture is required.
Tailored synthesis of TiC∕a-C nanocomposite tribological coatings
Authors: Martínez-Martínez D. , López-Cartes C. , Justo A. , Fernández A. , Sánchez-López J. C. , García-Luis A. , Brizuela M. , Oñate J. I.
Published: November 2005

Composite coatings made of nanocrystalline TiC (nc-TiC) particles and amorphous carbon (a-C) have been prepared in a double magnetron sputtering system using graphite and titanium targets under Ar bombardment. Chemical composition and microstructure of coatings were studied by transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), and x-ray diffraction (XRD) for a set of samples prepared varying the ratio and intensity of power applied to each magnetron. Changes in coatings microstructure, from a quasipolycrystalline TiC to a nanocomposite formed by nanocrystals of TiC embedded in an amorphous matrix of carbon (nc-TiC∕a-C), are observed depending on the synthesis conditions. Tribological and mechanical properties of coatings were tested using a pin-on-disk tribometer and an ultramicrohardness indenter, respectively. Coatings with moderate hardness (7–27GPa), low friction (0.1–0.2), and low wear rates (k∼10−7mm3∕Nm) were obtained. A percentage between 15% and 30% of TiC is found as an optimum value to get a good compromise between good mechanical and tribological properties. Finally, a mapping of the mechanical and tribological properties of the nc-TiC∕a-C system is presented for the synthesis conditions employed.
Thermal reaction of polycrystalline SiC with XeF2
Authors: Watanabe Morimichi , Mori Yukimasa , Sakai Hiroaki , Iida Takashi , Koide Shunsuke , Maeta Eri , Sawabe Kyoichi , Shobatake Kosuke
Published: November 2005

Studies on the thermal reaction behavior of polycrystalline cubic silicon carbide (SiC) with effusive xenon difluoride (XeF2) have been carried out over the sample temperature (Ts) range from 300to900K using molecular beam quadrupole mass spectrometry combined with a time-of-flight technique and ex situ surface analyses, i.e., x-ray photoelectron spectroscopy (XPS) and scanning Auger microscopy (SAM). Above Ts=700K, the reaction product desorbed from the SiC surface was identified as SiF4. The flux intensity of SiF4 increases monotonically as a function of Ts above 700K. The flux intensity of XeF2 desorbed from the SiC surface decreases above Ts=700K, and at Ts=900K, approximately 10% of the incident XeF2 was found to be consumed by the thermal reaction. No ions at m∕e=31 (CF+), 50 (CF2+), and 69 (CF3+) to be ascribed to carbon fluoride species were detected under the present experimental conditions, and thus C atoms in SiC were found to remain as residue. From the XPS and SAM observations of the SiC samples exposed to XeF2 vapor at 1.8×10−4Torr, we find that fluorination of a native oxide layer formed on the SiC surface takes place at Ts=300K. At Ts=520K, the native oxide layer was partially removed from the surface, and the presence of a reaction layer composed of partially fluorinated C atoms was observed. As Ts is increased above 520K, the reaction layer becomes thicker. Above Ts=700K, a thick reaction layer mainly composed of C atoms is formed, while only the near-surface reaction layer is fluorinated. The fast desorption of SiF4 products reduces the Si concentration in the SiC surface and the residual C atoms having comprised the SiC lattice are left as the reaction layer.
Sex Differences in the Brain: Implications for Explaining Autism
Authors: Baron-Cohen Simon , Knickmeyer Rebecca C. , Belmonte Matthew K.
Published: November 2005

Empathizing is the capacity to predict and to respond to the behavior of agents (usually people) by inferring their mental states and responding to these with an appropriate emotion. Systemizing is the capacity to predict and to respond to the behavior of nonagentive deterministic systems by analyzing input-operation-output relations and inferring the rules that govern such systems. At a population level, females are stronger empathizers and males are stronger systemizers. The “extreme male brain” theory posits that autism represents an extreme of the male pattern (impaired empathizing and enhanced systemizing). Here we suggest that specific aspects of autistic neuroanatomy may also be extremes of typical male neuroanatomy.