bluuebunny/crossref_metadata_2025 huggingface dataset:
A 24‐week course of high‐dose interferon‐α plus ribavirin for Taiwanese chronic hepatitis C patients with persistently normal or near‐normal alanine aminotransferase levels
Authors: Yu Ming‐Lung , Dai Chia‐Yen , Lee Li‐Po , Hou Nei‐Jen , Hsieh Ming‐Yen , Huang Jee‐Fu , Lin Zu‐Yau , Chen Shinn‐Cherng , Hsieh Ming‐Yuh , Wang Liang‐Yen , Chang Wen‐Yu , Chuang Wan‐Long
Published: November 2006

Abstract: Background/Aims: We aimed to evaluate the efficacy, advantage, and safety of a 24‐week regimen with high‐dose interferon‐α (INF‐α; 6 million units thrice weekly) plus ribavirin (1000–1200 mg/day) combination therapy for 46 Taiwanese chronic hepatitis C (CHC) patients with persistently normal or near‐normal alanine aminotransferase (PNALT) levels. Methods: Ninety‐two age‐ and sex‐matched CHC patients with elevated ALT levels (>2 times the upper limit of normal range) with a ratio of 1:2, treated with the same regimen, served as a control. Results: The sustained virologic response (SVR) rate was comparable between PNALT (67.4%) and elevated ALT (65.2%) groups (intention‐to‐treat analysis). The two groups had similar rates of discontinuation and incidence of adverse effects. Viral genotype 1b, baseline viral loads, body mass index, and age were significant factors negatively associated with SVR. Further decline of ALT levels throughout the follow‐up period was observed in sustained responders of the PNALT group. None of the eight patients with ALT flares developed icteric hepatitis. The virologic efficacy was sustained in a 3‐year extended follow‐up period. Conclusion: high‐dose INF‐α with ribavirin combination therapy is effective, safe, and well tolerated in CHC patients with PNALT levels. The ALT assay might not be used as a single biochemical marker for determination of treatment consideration.
Effects of Ginkgo biloba extract on cell proliferation, cytokines and extracellular matrix of hepatic stellate cells
Authors: Zhang Chunqing , Zhu Yuhua , Wan Jing , Xu Hongwei , Shi Henmei , Lu Xiaoxia
Published: November 2006

Abstract: Background/Aims: Hepatic fibrosis is the common wound‐healing response to chronic liver injury. Ginkgo biloba extract (GbE) has been indicated to reverse hepatic fibrosis and exhibit therapeutic effects both in vitro and in vivo. This study aimed to investigate the underlying mechanism of GbE using HSC‐T6 cells, a subline of hepatic stellate cells (HSC) as a model.

Methods: HSC‐T6 cells were seeded into six‐well plates and allowed to attach overnight. After exposure to different concentrations of GbE761 for 24 or 48 h, cell cycle analysis, semiquantitative RT‐PCR, Western blotting analysis and analysis of ECM secretion were performed.

Results: It was revealed that GbE (1, 10, 100, 500 mg/l) suppressed HSC proliferation and caused G0/G1 phase arrest in a concentration‐dependent manner. RT‐PCR and Western blot assays were applied to detect the decline of transforming growth factor β1(TGF‐β1) and connective tissue growth factor (CTGF) in both mRNA and protein levels after GbE treatment in HSC‐T6 cells for 24 or 48 h. Meanwhile, GbE inhibited the synthesis of type I and type III collagens. Secretion of some extracellular matrix (ECM) proteins, such as type III procollagen (PC III), type IV collagen (collagen IV), laminin (LN), hyaluronic acid (HA), were all decreased in supernatant of GbE treated HSC cells.

Conclusions: Our results suggest that GbE confers its anti‐fibrosis effects through inhibiting HSC proliferation, reducing TGF‐β1 and CTGF expression and consequently suppressing the collagen production and ECM secretion.
Correlation of transcutaneous hepatic near‐infrared spectroscopy readings with liver surface readings and perfusion parameters in a piglet endotoxemic shock model
Authors: Nahum E. , Skippen P. W. , Gagnon R. E. , Macnab A. J. , Skarsgard E. D.
Published: November 2006

Abstract: Purpose: To determine whether transcutaneous liver near‐infrared spectrophotometry (NIRS) measurements correlate with NIRS measurements taken directly from the liver surface, and invasive blood flow measurements.

Procedure: Laparotomy was performed in 12 Yorkshire piglets, and ultrasound blood flow probes were placed on the hepatic artery and portal vein. Intravascular catheters were inserted into the hepatic and portal veins for intermittent blood sampling, and a pulmonary artery catheter was inserted via the jugular vein for cardiac output measurements. NIRS optodes were placed on skin overlying the liver and directly across the right hepatic lobe. Endotoxemic shock was induced by continuous infusion of Escherichia coli lipopolysaccharide O55:B5. Pearson's correlations were calculated between the NIRS readings and the perfusion parameters.

Findings: After endotoxemic shock induction, liver blood flow, and oxygen delivery decreased significantly. There were statistically significant correlations between the transcutaneous and liver‐surface NIRS readings for oxyhemoglobin, deoxyhemoglobin, and cytochrome c oxidase concentrations. There were similar significant correlations of the transcutaneous oxyhemoglobin with both the mixed venous and hepatic vein saturation, and mixed venous and hepatic vein lactate.

Conclusions: Transcutaneous NIRS readings of the liver, in an endotoxemic shock model, correlate with NIRS readings taking directly from the liver surface, as well as with global and specific organ‐perfusion parameters.
Clinical significance of HLA DRB1*03–DRB1*04 in type 1 autoimmune hepatitis
Authors: Montano‐Loza Aldo J. , Carpenter Herschel A. , Czaja Albert J.
Published: November 2006

Abstract: Background: HLA DRB1*03–DRB1*04 combines both susceptibility factors for type‐1 autoimmune hepatitis.

Aims: Determine whether this phenotype is a risk factor for autoimmune hepatitis in white North American patients, assess its associations with clinical features and treatment outcome, and determine whether alleles within this phenotype affect prognosis.

Methods: One hundred and ninety‐eight patients with type 1 autoimmune hepatitis and 102 normal adults were evaluated. HLA typing was performed by DNA‐based techniques.

Results: Twenty‐eight patients had HLA DRB1*03–DRB1*04, and the frequency was higher than in normal subjects (14% vs 4%, OR 4.0%, 95% CI 1.4–11.8, P=0.01). Patients with DRB1*03–DRB1*04 relapsed less frequently than patients with DRB1*03 (1.3±0.3 vs 2.1±0.2, P=0.04), but they otherwise had outcomes similar to patients with other phenotypes. Patients with DRB1*03‐DRB1*04 who had 3–4 alleles encoding lysine at position DRβ71 within the class II molecule of the major histocompatibility complex developed cirrhosis more commonly (75% vs 9%, P=0.05) and had a higher frequency of hepatic‐related death or liver transplantation (40% vs 0%, P=0.04) than patients with fewer alleles.

Conclusions: HLA DRB1*03–DRB1*04 is a risk factor for type‐1 autoimmune hepatitis, and its impact on outcome relates to the diversity of DRB1*04 alleles that encode a critical motif.
Influence of autologous platelet concentrate on healing in intra‐bony defects following guided tissue regeneration therapy: a randomized prospective clinical split‐mouth study
Authors: Christgau M. , Moder D. , Wagner J. , Gläßl M. , Hiller K.‐A. , Wenzel A. , Schmalz G.
Published: November 2006

Abstract
Objectives: To investigate the influence of autologous platelet concentrate (APC) on early wound healing and regeneration outcomes following guided tissue regeneration (GTR) therapy.

Material and Methods: In 25 patients, two contralateral deep intra‐bony defects were treated with β‐TCP and a bioresorbable GTR membrane. They were randomly assigned to test and control procedure. In test defects, APC was additionally applied. After 3, 6, and 12 months, healing results were assessed by clinical parameters and quantitative digital subtraction radiography.

Results: Post‐operative membrane exposures occurred in 48% of the test sites and 80% of the control sites. Both groups revealed a significant clinical attachment level (CAL) gain of 5 mm after 12 months. Eighty‐eight per cent of test and control sites showed a CAL gain of 4 mm. No clinical parameter revealed significant differences between test and control sites. A significant bone density gain was found in both groups after 3, 6, and 12 months. Only after 6 months, the bone density gain was significantly greater in the test defects.

Conclusion: Within the limits of this study, autologous platelet concentrate did not seem to have a noticeable influence on the clinical and most of the radiographic outcomes following GTR. However, APC might reduce the occurrence of post‐operative membrane exposures and accelerate bone density gain.
Subgingival microbiota of periodontally untreated Mexican subjects with generalized aggressive periodontitis
Authors: Ximenez‐Fyvie Laurie Ann , Almaguer‐Flores Argelia , Jacobo‐Soto Velia , Lara‐Cordoba Monica , Moreno‐Borjas Jazmin‐Yunuen , Alcantara‐Maruri Eulalio
Published: November 2006

Background and Aim: Specific microbial profiles that may distinguish between generalized aggressive‐periodontitis (GAgP) and generalized chronic‐periodontitis (GCP) have, to date, not been described. The purpose of the present study was to describe the subgingival microbial composition of Mexican subjects with GAgP and compare it with that of individuals with GCP and periodontal health (PH).

Material and Methods: Seventy‐seven subjects with GAgP (n=19), GCP (n=39) and PH (n=19) were selected. Clinical measurements included plaque accumulation, gingival erythema, bleeding on probing, suppuration, pocket depth and attachment level. Up to 28 subgingival plaque samples were obtained from each subject and analysed using the checkerboard DNA–DNA hybridization technique.

Results: GAgP and GCP subjects harboured significantly higher levels and/or proportion of Porphyromonas gingivalis, Tannerella forsythia (levels: p<0.001, proportion: p<0.01), Prevotella nigrescens (p<0.05 levels) and “red” complex species (p<0.001 proportion) than PH subjects. All GAgP subjects were carriers of P. gingivalis and P. nigrescens. No significant differences in any of the 40 microbial species tested were detected between GAgP and GCP subjects.

Conclusions: Our results revealed that the microbial differences between GAgP and GCP subjects were only discrete and none of the bacterial species tested seemed to specifically differentiate the subgingival microbial profile of either periodontitis group.
Rehardening of caries‐like lesions in root surfaces by saliva substitutes
Authors: Turssi Cecilia P. , Lima Renata Q. V. , Faraoni‐Romano Juliana J. , Serra Mônica C.
Published: November 2006

Objective:  This study sought to evaluate whether root dentine caries‐like lesions could be remineralised by saliva substitutes.

Methods:  Root dentine slabs (3 × 3 × 2 mm) were cut from bovine incisors, ground flat, polished and pre‐tested for Knoop microhardness (KHN) at five locations spaced 500 μm apart and 500 μm from the left edge of each sectioned piece. After 60 out of the 100 slabs had been selected based upon their KHN values, specimens were coated with wax except for their outer surface. Specimens were then cycled through a highly cariogenic challenge model to induce caries‐like lesions, whose formation was confirmed by KHN measurements located 500 μm from the right edge of the specimen. According to a randomised complete block design, the experimental units (n = 15) were exposed to 1.5 ml of saliva substitutes, based on either mucin (MC) or carboxymethylcellulose (CM), to natural human saliva (HS) or to 100% relative humidity (RH) over 20 days. Remineralisation was verified by KHN measurements located 1000 μm apart from the right edge of the specimen.

Results:  Analysis of variance indicated a significant (p < 0.0001) difference among the KHN values attained by the carious root dentine after exposure to the remineralising agents. Tukey's test ascertained that remineralisation was greatest with MC, intermediate with CM and least with HS, but rehardening did not reach the pre‐caries lesion formation values.

Conclusion:  Saliva substitutes may provide partial remineralisation to preformed caries‐like lesions in root dentine.
Relationship of cariogenic bacteria levels with periodontal status and root surface caries in elderly Japanese
Authors: Saotome Yasuhiko , Tada Akio , Hanada Nobuhiro , Yoshihara Akihiro , Uematsu Hiroshi , Miyazaki Hideo , Senpuku Hidenobu
Published: November 2006

Objective:  The relationship of the levels of cariogenic bacterial species with periodontal status and decayed root surfaces was investigated in elderly Japanese subjects.

Methods:  Three hundred and sixty‐eight individuals (each 75 years old) were examined for periodontal status (pocket depth, attachment loss), root surface caries and salivary levels of mutans streptococci (MS) and lactobacilli (LB).

Results:  Values >4 mm of attachment loss (rAL4) and for average attachment loss (aAL) of sites measured were significantly higher in subjects with LB than those without. Multiple regression analysis also showed a correlation between aAL and rAL4 values with the presence of LB (aAL p = 0.003; rAL4 p = 0.002). Further, multiple regression analysis of interacting factors regarding decayed root surfaces showed that LB carriers had a greater incidence of decayed root surface caries (p = 0.003), while MS and LB levels were correlated to the number of decayed root surfaces (LB p = 0.010; MS p = 0.026).

Conclusion:  Our results indicate that considerable attachment loss elevates the possibility of having LB, thus increasing the risk of root surface caries. It was also found that LB and MS measurements may be useful indicators of decayed root surfaces in elderly individuals with attachment loss.
Geriatric dentistry in Brazilian universities
Authors: De Lima Saintrain Maria Vieira , De Souza Eliane Helena Alvim , De França Caldas Júnior Arnaldo
Published: November 2006

The World Health Organization has predicted an increase in the population of elderly people.

Objective:  The purpose of this study was to investigate the teaching of geriatric dentistry in Brazilian universities.

Materials and methods:  This study consisted of questionaires regarding the training in geriatric dentistry in 104 dental schools included in the National Institute of Education Research (INEP) in 2001. In order to calculate the sample (a random stratified one), the confidence interval was set at 99% and a maximum permitted error of 3% was adopted. Pearson's chi‐square test was used in the inferential analysis.

Results:  From the 64 dental courses which were studied, only 25 included geriatric dentistry in the curriculum. From 1857 students who were involved in the study, 41% sought knowledge outside the dental school and 98% considered that it was important that this subject should be included in the curriculum. There was statistical significance between geriatric dentistry teaching and the students’ preference as well as the prospect of working with this group of the population. Geriatric dentistry as an individual subject was absent from the curriculum in two‐thirds of the dental courses investigated. Knowledge was often transmitted as part of dental prosthetics and most of the students stated that they would want to be able to treat elderly people. It was relevant to note that senior students expected to work in this field.

Conclusion:  Dental students in Brazil do not have adequate training in geriatric dentistry.
EFFECT OF COOKING OF RICE BRAN ON THE QUALITY OF EXTRACTED OIL
Authors: ANIL KUMAR H.G. , KHATOON S. , PRABHAKAR D.S. , KRISHNA A.G. GOPALA
Published: November 2006

While attempting to prepare a nutritionally superior rice bran oil, the effect of cooking of rice bran with various levels of added water on the quality of bran and extracted oil was studied. The rice bran (from IR‐64 paddy, Indian variety) used was obtained from a local rice mill having 8% moisture and 19.3% fat. The levels of water incorporated were 0, 6, 12, 25, 50, 100, 200 and 400 g/100 g bran and were heated to boil (or to reach 105–110C) for 20 min and the contents cooled and dried in air. A sample of 100 g bran was heated similarly without the addition of water, which served as a control. The oil extracted from the control bran had color, 80 Lovibond units, free fatty acids (FFAs), 27%, tocopherols and tocotrienols, 103 mg per 100 g (mg%), and oryzanol, 2.39%. The water‐treated, cooked and dried bran samples were extracted with hexane to recover the oil which had a lower Lovibond color (65–70), varied FFA (as % oleic acid) (25.4–33.2%) levels, reduced tocopherol and tocotrienol (3.9–62.3 mg%) content and a slightly higher oryzanol content (2.51–2.70%) compared to the oil extracted from the control bran. The changes were observed from the start at 6 and 12 g water/100 g bran addition stage itself and almost all tocopherols and tocotrienols (97–99%) were destroyed, while at the 50‐ to 400‐g water addition stages tocopherol and tocotrienol destruction ranged from 51 to 72%. The study sheds light on the deleterious effect on tocopherols and tocotrienols in rice bran and extracted oil during cooking of rice bran, although there is an improvement in color and texture of cooked bran and color and oryzanol content of the extracted oil.
RHEOLOGICAL PROPERTIES OF COCOA BUTTER SUBSTITUTE (CBS): EFFECTS OF TEMPERATURE AND CHARACTERISTICS OF FATTY ACIDS ON VISCOCITY
Authors: SHAMSUDIN ROSNAH , MOHAMED IBRAHIM O. , NOOI TAN S.
Published: November 2006

Rheology properties of three samples of cocoa butter substitutes (CBS) with different fatty acid compositions were determined using a concentric cylinder rheometer. The measurements were carried out over a shear rate range of 0–1,000 1/s, at five different levels of temperature ranging from 40 to 60C. The results of the experimental measurements revealed that CBS behaved as a Newtonian fluid over the temperature and shear rate range investigated. Furthermore, the results showed that the viscosity increases with increasing percentage of long‐chain saturated fatty acids rather than the overall increase in percentage of saturated fatty acids. However, the variation of viscosities among the three samples was found insignificant at α = 0.01, allowing pooling of the data and developing a viscosity model as a function of temperature for the CBS.
STATISTICAL ANALYSES FOR R‐INDEX
Authors: BI JIAN
Published: November 2006

R‐index is an important statistic for testing and measuring product effects. The validation and merits of R‐index are to a great extent due to the fact that it is closely related to the famous Mann–Whitney U statistic. Based on this fortunate relationship, statistical analyses for R‐index are explored. The statistical analyses include estimations of R‐index and its null and nonconditional variances with and without assuming continuity of data; difference and similarity tests using R‐index; powers and sample sizes for the tests; linking R‐index with Thurstonian δ (or d′). The new techniques developed in the paper extend greatly the original R‐index analysis for categorical ratings data. It is expected that the recognition of the profound theoretical origin of R‐index and the available statistical analyses for R‐index will provide the impetus for the resurgence of interest in using R‐index in sensory and consumer researches.
An Exact Algebraic Evaluation of Path-Length Difference for Two-Source Interference
Authors: Hopper Seth , Howell John
Published: November 2006

When studying wave interference, one often wants to know the difference in path length for two waves arriving at a common point P but coming from adjacent sources. For example, in many contexts interference maxima occur where this path-length difference is an integer multiple of the wavelength. The standard approximation for the path-length difference is path-length difference≈dsin θ, where d is the distance between the sources and θ is the angle between the perpendicular bisector of d and the line connecting P to the midpoint of d. A common derivation of Eq. (1) begins with the seemingly paradoxical approximation that two paths that meet at a common point can be treated as parallel. In this paper we present an alternative derivation that first finds a simple, exact expression for the path-length difference, valid even when the paths clearly are not parallel. We then show the circumstances under which Eq. (1) is a useful approximation to the exact expression and finally determine an upper limit to the error inherent in using Eq. (1) in place of the exact expression. No math is required beyond the Pythagorean theorem and simple algebra.
Calculating g from Acoustic Doppler Data
Authors: Torres Sebastián M. , González-Espada Wilson J.
Published: November 2006

Traditionally, the Doppler effect for sound is introduced in high school and college physics courses. Students calculate the perceived frequency for several scenarios relating a stationary or moving observer and a stationary or moving sound source. These calculations assume a constant velocity of the observer and/or source. Although seldom discussed in this context, generalization of the Doppler effect for accelerated sound sources is relatively straightforward and can be used as an enriching tool in the classroom. The purpose of this paper is to describe a simple experiment to determine the acceleration of gravity (g) from an acoustic source in free fall.
Law of Conservation of Momentum Apparatus
Authors: Saitoh Akio
Published: November 2006

Two plates are set up horizontally, 4.1 cm apart, one above the other as shown in Fig. 1. The upper acrylic plate has a total of 405 small drilled holes. A fine stainless steel wire is inserted through each hole and adjusted so that one end of the wire is 1.8 cm above the lower wooden plate. The other end of the wire is taped to the upper plate and connected to the positive terminal of the power supply.
Galactose Starvation in a Bloodstream Form
Trypanosoma brucei
UDP-Glucose 4′-Epimerase Conditional Null Mutant
Authors: Urbaniak Michael D. , Turnock Daniel C. , Ferguson Michael A. J.
Published: November 2006

Galactose metabolism is essential for the survival of
Trypanosoma brucei
, the etiological agent of African sleeping sickness.
T. brucei
hexose transporters are unable to transport galactose, which is instead obtained through the epimerization of UDP-glucose to UDP-galactose catalyzed by UDP-glucose 4′-epimerase (
galE
). Here, we have characterized the phenotype of a bloodstream form
T. brucei galE
conditional null mutant under nonpermissive conditions that induced galactose starvation. Cellular levels of UDP-galactose dropped rapidly upon induction of galactose starvation, reaching undetectable levels after 72 h. Analysis of extracted glycoproteins by ricin and tomato lectin blotting showed that terminal β-
d
-galactose was virtually eliminated and poly-
N
-acetyllactosamine structures were substantially reduced. Mass spectrometric analysis of variant surface glycoprotein confirmed complete loss of galactose from the glycosylphosphatidylinositol anchor. After 96 h, cell division ceased, and electron microscopy revealed that the cells had adopted a morphologically distinct stumpy-like form, concurrent with the appearance of aberrant vesicles close to the flagellar pocket. These data demonstrate that the UDP-glucose 4′-epimerase is essential for the production of UDP-galactose required for galactosylation of glycoproteins and that galactosylation of one or more glycoproteins, most likely in the lysosomal/endosomal system, is essential for the survival of bloodstream form
T. brucei.
Nonsense-Mediated mRNA Decay Mutation in
Aspergillus nidulans
Authors: Morozov Igor Y. , Negrete-Urtasun Susana , Tilburn Joan , Jansen Christine A. , Caddick Mark X. , Arst Herbert N.
Published: November 2006

An
Aspergillus nidulans
mutation, designated
nmdA1
, has been selected as a partial suppressor of a frameshift mutation and shown to truncate the homologue of the
Saccharomyces cerevisiae
nonsense-mediated mRNA decay (NMD) surveillance component Nmd2p/Upf2p.
nmdA1
elevates steady-state levels of premature termination codon-containing transcripts, as demonstrated using mutations in genes encoding xanthine dehydrogenase (
hxA
), urate oxidase (
uaZ
), the transcription factor mediating regulation of gene expression by ambient pH (
pacC
), and a protease involved in pH signal transduction (
palB
).
nmdA1
can also stabilize pre-mRNA (unspliced) and wild-type transcripts of certain genes. Certain premature termination codon-containing transcripts which escape NMD are relatively stable, a feature more in common with certain nonsense codon-containing mammalian transcripts than with those in
S. cerevisiae.
As in
S. cerevisiae
, 5′ nonsense codons are more effective at triggering NMD than 3′ nonsense codons. Unlike the mammalian situation but in common with
S. cerevisiae
and other lower eukaryotes,
A. nidulans
is apparently impervious to the position of premature termination codons with respect to the 3′ exon-exon junction.
Clonal Complexes of
Campylobacter jejuni
Identified by Multilocus Sequence Typing Are Reliably Predicted by Restriction Fragment Length Polymorphism Analyses of the
flaA
Gene
Authors: Djordjevic Steven P. , Unicomb Leanne E. , Adamson Penelope J. , Mickan Lance , Rios Rosa ,   the Australian Campylobacter Subtyping Study Group
Published: November 2006

Multilocus sequence typing (MLST) has provided important new insights into the population structure of
Campylobacter jejuni
and is rapidly becoming the gold standard for typing this species. However, the methodology is comparatively costly and slow to perform for the routine surveillance testing of large numbers of isolates required by public health laboratories. Restriction fragment length polymorphism analysis of the
flaA
gene (RFLP-
flaA
) and sequencing of the variable region in the
fla
locus (SVR-
fla
) were compared to MLST to determine if a low cost alternative could be found that reliably predicts clonal lineage (as determined by MLST). An isolate of
C. jejuni
from each of 153 patients from New South Wales, Australia, collected sequentially over a period of 30 months from 1999 to 2001 and comprising 40 sequence types (ST) from 15 clonal complexes (CC) was examined. Of 15 CC, 12 were represented by more than one isolate and a predominant RFLP-
flaA
type was found for 10 (83%). Of these, seven (70%) correctly predicted the predominant MLST CC with a probability of >0.8. Of 40 STs detected, 19 were reported for the first time, 9 of which were represented by more than one isolate. Eight of these were represented by a single RFLP-
flaA
type. Only two of eight major SVR-
fla
types were able to predict CC with a probability of >0.8, indicating that
flaA
-RFLP is a more reliable predictor of CC than SVR-
fla
and thus offers an alternative to MLST for use in routine surveillance.
Persistent disturbance by commercial navigation alters the relative abundance of channel-dwelling fishes in a large river
Authors: Gutreuter Steve , Vallazza Jon M , Knights Brent C
Published: November 2006

We provide the first evidence for chronic effects of disturbance by commercial vessels on the spatial distribution and abundance of fishes in the channels of a large river. Most of the world's large rivers are intensively managed to satisfy increasing demands for commercial shipping, but little research has been conducted to identify and alleviate any adverse consequences of commercial navigation. We used a combination of a gradient sampling design incorporating quasicontrol areas with Akaike's information criterion (AIC)-weighted model averaging to estimate effects of disturbances by commercial vessels on fishes in the upper Mississippi River. Species density, which mainly measured species evenness, decreased with increasing disturbance frequency. The most abundant species — gizzard shad (Dorosoma cepedianum) and freshwater drum (Aplodinotus grunniens) — and the less abundant shovelnose sturgeon (Scaphirhynchus platorhynchus) and flathead catfish (Pylodictis olivaris) were seemingly unaffected by traffic disturbance. In contrast, the relative abundance of the toothed herrings (Hiodon spp.), redhorses (Moxostoma spp.), buffaloes (Ictiobus spp.), channel catfish (Ictalurus punctatus), sauger (Sander canadensis), and white bass (Morone chrysops) decreased with increasing traffic in the navigation channel. We hypothesized that the combination of alteration of hydraulic features within navigation channels and rehabilitation of secondary channels might benefit channel-dependent species.
Ecosystem models show combined effects of fishing, predation, competition, and ocean productivity on Steller sea lions (Eumetopias jubatus) in Alaska
Authors: Guénette Sylvie , Heymans Sheila JJ , Christensen Villy , Trites Andrew W
Published: November 2006

Steller sea lions (Eumetopias jubatus) increased in the eastern portion of their range while declining in the Gulf of Alaska and Aleutian Islands from the late 1970s to late 1990s. We constructed ecosystem models of the central and western Aleutians and of southeast Alaska to simultaneously evaluate four hypotheses explaining sea lion dynamics: killer whale (Orcinus orca) predation, ocean productivity, fisheries, and competition with other species. Comparisons of model predictions with historical time series data indicate that all four factors likely contributed to the trends observed in sea lion numbers in both ecosystems. Changes in ocean productivity conveyed by the Pacific Decadal Oscillation influenced the abundance trajectory of several species. Fishing could have affected the ecosystem structure by influencing the abundance of Atka mackerel (Pleurogrammus monopterygius) in the Aleutians and Pacific herring (Clupea pallasii) in southeast Alaska. Pacific halibut (Hippoglossus stenolepis) in the Aleutians and arrowtooth flounder (Atheresthes stomias) in southeast Alaska appear to impede sea lion population growth through competitive interactions. Predation by killer whales was important when sea lions were less abundant in the 1990s in the Aleutians and in the 1960s in Southeast Alaska, but appear to have little effect when sea lion numbers were high.
Forms and sand transport in shallow hydraulic fractures in residual soil
Authors: Murdoch Lawrence C , Richardson James R , Tan Qingfeng , Malin Shaun C , Fairbanks Cedric
Published: November 2006

Four sand-filled hydraulic fractures were created at a depth of 1.5 m, and the vicinities of the fractures were excavated and mapped in detail. All the fractures were shaped like slightly asymmetric saucers between 4.5 and 7.0 m across that were roughly flat-lying in their centers and curved upward to dip between 10° and 15° along their peripheries. Three different colors of sand were injected in sequence to trace the relative ages of the sand in the fracture. The first sand to be injected remained in the vicinity of the injection casing, whereas the last sand moved rapidly to the leading edge. Sand transport occurred through localized, channel-like pathways that extended from the injection casing and then branched into multiple paths as they approached the leading edge. At least four branching pathways of different ages were identified in one fracture, suggesting that this represents a fundamental mechanism of sand transport in these shallow fractures. A theoretical model was developed by adapting Franc2d, a code well-known in structural mechanics, to predict the propagation paths of curved hydraulic fractures at shallow depths. The model predicts fracture forms that are remarkably similar to those in field exposures when properties typical of field conditions are used.Key words: hydraulic fracture, field test, mechanics, modeling.
Revising the areal extent of post-earthquake inspections of dams in Quebec
Authors: Lamontagne Maurice , Dascal Oscar
Published: November 2006

Post-earthquake inspection is required by many dam safety regulations. Typically, based on the magnitude of the earthquake, the guidelines define an area within which dams should be inspected. The areas are established on ground-motion relations derived for the western United States. In eastern North America (ENA), the attenuation is slower with distance from the earthquake epicentre, and as a consequence the inspection area should be significantly larger than that recommended by the current guidelines. We review the state of knowledge on earthquake damage to dams, the factors used to define post-earthquake inspections, and the earthquake characteristics used to define the guidelines. We recommend new radii of inspections for dams applicable in ENA, including the Province of Quebec. Derived from historical earthquake information, the proposed new radii of inspections are twofold to sixfold larger than the 1988 guidelines of the International Commission on Large Dams. It is also suggested that a half-magnitude unit be added to every magnitude “rapidly” released by seismological organizations to include the intrinsic uncertainty in magnitude values and types. Our proposed approach is only one avenue that dam owners can follow to comply with dam safety regulations. Irrespective of the avenue chosen, however, this paper emphasizes the need for dam owners to consider the lower ground motion attenuation in ENA.Key words: earthquake, damage, dam, inspection, natural hazards, emergency response.
Effect of Pulse Duration on Formation of Ultrashallow Junction by Excimer Laser Annealing
Authors: Matsuno Akira , Shibahara Kentaro
Published: November 2006

An ultrashallow junction (USJ) was formed by KrF excimer laser annealing. The effect of laser pulse duration on USJ formation was discussed through the evaluations of junction depth, sheet resistance and crystal defects. The possibility of reducing crystal defects by long-pulse laser annealing was discussed. A simple one-dimensional thermal diffusion model was used to analyze the results considering the solidification velocity after melting. The calculated results for the relationship between melt depth and laser energy density qualitatively agreed well with the experimental results. The results also showed that longer pulse duration made solidification velocity lower. Lower solidification velocity is the key to reducing the residual defects.
Formation of New Beryllium Phosphide in Au(Be)/GaP Thin-Film System
Authors: Cheng Wei-Chun , Lin Hsin-Li
Published: November 2006

A new beryllium phosphide was discovered in a Au/AuBe/Au/p-GaP(111) thin-film system annealed at 500 °C by rapid thermal annealing (RTA). The beryllium phosphide appeared in the shape of a plate in a gold metallization layer near the GaP substrate after RTA. The crystal structure of the beryllium phosphide belongs to the fcc Bravais lattice. The lattice constant of the beryllium phosphide is about 0.4996 nm. The formation of beryllium phosphide was confined to the cubic-to-cubic orientation relationships with that of GaP. The crystal structure of the beryllium phosphide does not pertain to those of any known binary beryllium phosphide systems. Thus, it was concluded that this beryllium phosphide, accordingly, is a new discovery.
Filling 80-nm-Wide and High-Aspect-Ratio Trench with Pulse Wave Copper Electroplating and Observation of the Microstructure
Authors: Chonan Yasunori , Onuki Jin , Nagano Takahiro , Khoo Khyoupin , Aoyama Takashi , Akahoshi Haruo , Haba Toshio , Saito Tatsuyuki
Published: November 2006

To completely fill 80-nm-wide trenches with high-aspect-ratio (>6) Cu electroplating, we investigated the influence of pulse wave electroplating conditions. Peak current density and current-off time during pulse wave plating were found to affect bottom-up filling. Bottom-up filling was confirmed to occur when peak current density, current-on time and current-off time were 100 mA/cm2, 3 and 300 ms, respectively. The microstructure of the trench was observed before and after annealing at 673 K by transmission electron microscope. After annealing, the grain size increases and grains cross the trench width. The size of grains formed by pulse wave plating before and after annealing were 37.5 and 96 nm, respectively. These values were similar to those for DC plating. Pulse wave electroplating is, therefore, promising as a step in the dual damascene process for fabricating very narrow high-aspect-ratio Cu wiring.
Characterizing the Channel Backscattering Behavior in Nanoscale Strained Complementary Metal Oxide Semiconductor Field-Effect Transistors
Authors: Lin Hong-Nien , Chen Hung-Wei , Ko Chih-Hsin , Ge Chung-Hu , Lin Horng-Chih , Huang Tiao-Yuan , Lee Wen-Chin
Published: November 2006

This work investigates the impact of different uniaxial strain polarities on channel backscattering in nanoscale complementary metal oxide semiconductor field-effect transistor (CMOSFET). Two carrier statistics, nondegenerate and degenerate-limited, are employed to extract the channel backscattering ratio, ballistic efficiency, and related backscattering factors. While the channel length scales down and the channel stress level increases further, the modulation of channel backscattering ratio, i.e., improved (degraded) by uniaxial tensile (compressive) strain, becomes more prominent. This observation holds true under both carrier statistics, which implies that the nondegenerate case with simple mathematics can be fairly used for evaluation. In addition, the correlation between strain-enhanced mobility gain and drain current improvement is found to be predicted well by the ballistic efficiency deduced with the nondegenerate carrier statistics.
Multiscale Monte Carlo Simulation of Circular DC Magnetron Sputtering: Influence of Magnetron Design on Target Erosion and Film Deposition
Authors: Kwon Ui Hui , Lee Won Jong
Published: November 2006

We present an experimental and computational study of the effect of magnetron design on the target erosion profile, wafer-level deposition uniformity, and feature-scale deposition topography in a circular DC magnetron sputtering system. We have conducted a multiscale Monte Carlo simulation consisting of a particle-in-cell Monte Carlo collision plasma simulation for target sputter erosion, a collisional transport simulation for film deposition, and a feature-scale deposition topography simulation. The entire simulation results for each step are verified in comparison with the experimental results for various process conditions. A new semiempirical calibration method, for converting an estimated ion current density distribution into a target erosion profile, is proposed with regard to the gas rarefaction effect due to sputtering wind. In conclusion, the whole performance indices of a circular DC magnetron sputtering system are substantially influenced by magnetron design, and the effectiveness of our multiscale Monte Carlo simulation methodology is validated.
High-Temperature Metal-Organic Vapor Phase Epitaxial Growth of AlN on Sapphire by Multi Transition Growth Mode Method Varying V/III Ratio
Authors: Imura Masataka , Nakano Kiyotaka , Fujimoto Naoki , Okada Narihito , Balakrishnan Krishnan , Iwaya Motoaki , Kamiyama Satoshi , Amano Hiroshi , Akasaki Isamu , Noro Tadashi , Takagi Takashi , Bandoh Akira
Published: November 2006

High-quality AlN layers were grown on c-plane sapphire substrates by high-temperature metal-organic vapor phase epitaxy. AlN layers of about 9 µm in thickness with an atomically flat surface were obtained without cracks. Multiple modulation of the V/III ratio during growth led to a reduction in the number of dislocations during the growth transition period. The dislocation density of the AlN layers was found to be less than 3×108 cm-2.
(111)-Oriented Zn3N2 Growth on a-Plane Sapphire Substrates by Molecular Beam Epitaxy
Authors: Oshima Takayoshi , Fujita Shizuo
Published: November 2006

(111)-oriented Zn3N2 thin films were grown on a-plane (1120) sapphire substrates by plasma-assisted molecular beam epitaxy. Zn3N2/sapphire exhibits orientational relationships of out-of-plane <111>∥[1120] and in-plane almost <110>∥[0001] and <101>∥[0001]. These specific orientations result from similar surface configurations of N atoms in Zn3N2 and Al atoms in sapphire at the interface. Under the optimum growth conditions, the film showed a full width at half maximum of 185 arcsec for an X-ray (222) diffraction rocking curve and a root-mean-square roughness of 8.5 Å in an atomic force microscope image. These results suggest that a-plane sapphire is a suitable heteroepitaxial substrate for high-quality Zn3N2 thin films.
Structural and Electroluminescence Characteristics of Nonpolar Light-Emitting Diodes Fabricated on Lateral Epitaxially Overgrown a-Plane GaN
Authors: Chakraborty Arpan , Kim Kwang Choong , Wu Feng , Haskell Benjamin A. , Keller Stacia , Speck James S. , Nakamura Shuji , DenBaars Steven P. , Mishra Umesh K.
Published: November 2006

We report on the structural and electroluminescence characteristics of blue and cyan a-plane InGaN/GaN light-emitting diodes (LEDs). Cross-sectional transmission emission microscopy revealed the generation of occasional “asymmetric V-defects” in the active region. The blue and cyan LEDs exhibited rectifying behavior with forward voltages of 2.4 and 3.5 V at 20 mA, respectively and series resistances of 7 and 8 Ω, respectively. On-wafer dc output powers as high as 1.8 and 1.0 mW were measured at a drive current of 300 mA for the blue and the cyan LEDs, respectively. Electroluminescence measurement revealed an initial blue shift in the emission wavelength with the increase in the drive current. We speculate that the emission wavelength shift is due to the band-filling effect as a result of localization in the inclined non-{1120} oriented facets, which are polar in nature.
Effects of Nano scale Y2O3 Additions on Sm–Ba–Cu–O Materials
Authors: Chen Shih-Yun , Chen In-Gann , Wu Maw-Kuen
Published: November 2006

To enhance the critical current density (J
c) of Sm–Ba–Cu–O (SmBCO) superconductors, a small number of Y2O3 particles of nano scale (nmY2O3) were used. The J
c–H (the applied magnetic field) results show that the increase in J
c using nmY2O3 occurs mainly in high fields. In addition, by increasing the number of nmY2O3 particles, the flux pinning force-reduced magnetic field (F
p–h) curves shift to the right. The above results indicate the formation of δT
c pinning centers. The microstructure results show that Y2O3 particles react with the 211 (Sm2BaCuO5), 123 (Sm1Ba2Cu3O7) and liquid phases at high temperatures. Both the high solubility of Sm in the liquid and the inter-diffusion of Sm and Y at high temperatures result in compositional fluctuations [(Sm,Y)–Ba–Cu–O]. It is considered that these compositional fluctuations contribute to δT
c pinning. Finally, to determine the effect of compositional fluctuation caused by a different method, these results were also compared with those of the nano sized Y211 (nmY211)-doped samples.
Electrical and Magnetic Properties and Colossal Magnetoresistance Effect of La1-xBixMnO3
Authors: Ogawa Takashi , Shindo Haruo , Takeuchi Hiromasa , Koizumi Yoshiharu
Published: November 2006

Perovskite-type La1-x
Bi
x
MnO3 (LBMO) crystals, which were prepared by doping a Bi atom for a La atom in LaMnO3, were shown to exhibit the colossal magnetoresistance (CMR) effect. Samples were produced by sintering in an air atmosphere that depended on the Bi composition ratio x. X-ray diffraction measurements showed that the LBMO crystal structure can be orthorhombic (or rhombohedral) with γ (=c/a)=1.02 for 0.0<x<0.3, cubic with γ=1.005 for 0.3<x<0.5 or monoclinic with γ=1.014 for 0.5<x. The CMR effect of LBMO for x=0.2 was approximately 400% at 88 K. In addition, the magnetoresistance of LBMO was found to be proportional to the square of magnetization. On the basis of these results, the CMR occurrence mechanics of LBMO were shown to significantly contribute to a Mn3+–Mn4+ double exchange interaction, which is closely associated with the cooperative phenomenon in the Jahn–Teller effect.
High-Heat Generation Ability in AC Magnetic Field for Ti Tube Filled with Ferrite Powder
Authors: Hirazawa Hideyuki , Uchihara Kodai , Aono Hiromichi , Hiraoka Koichi , Naohara Takashi , Nomura Shinfuku , Maehara Tsunehiro , Watanabe Yuji
Published: November 2006

Needle-type materials were studied for the application of thermal coagulation therapy in an AC magnetic field. We found that the Ti tube filled with ferrite powder as the core had a high heat generation ability in an AC magnetic field. Although the Ti tube without the ferrite powder or Ti rod showed poor heat generation abilities, the temperature was significantly increased by the existence of ferrite powder in the tube. In this case, the ferrite powder seems to improve the eddy loss for the Ti tube. The maximum heat generation ability was obtained for the Ti tube that contained MgFe2O4 powder in the examined Ti tube with some ferrites.
Reversal of UV Sensitivity and Loss Reduction of SiON Microring Resonator by Thermal Annealing
Authors: Ueno Satoshi , Tatewaki Takashi , Ohdaira Toshiyuki , Shioya Yoshimi , Kokubun Yasuo
Published: November 2006

To investigate the origin of the large UV sensitivity of SiON film, we measureed the Fourier transform infrared (FT-IR) spectrum of SiON films before and after UV exposure, and also before and after thermal annealing. As a result, we discovered the reversal of the UV sensitivity of SiON film treated by thermal annealing at 1160 °C. Next, the origin of the reversal of UV sensitivity induced by thermal annealing was studied by positron annihilation lifetime spectroscopy (PALS) measurement. The redshift trimming of a microring resonator with a SiON core and the improvement of a double series coupled microring resonator by selective UV trimming were successfully demonstrated using this phenomenon.
Velocity-Matching Conditions for Ultrahigh-Speed Optical LiNbO3 Modulators with Traveling-Wave Electrode
Authors: Aoki Kenji , Kondou Jungo , Mitomi Osamu , Minakata Makoto
Published: November 2006

In traveling-wave-type optical modulators, the microwave effective index should match the optical group index to realize a maximum bandwidth and a minimum driving voltage. Considering the material dispersion of LiNbO3 (LN) and the waveguide dispersion of a Ti-diffused optical waveguide, we obtained a waveguide group index of 2.189 at a wavelength of 1550 nm, which is 0.051 larger than the waveguide phase index, from both calculation and experimental results. The effect of the waveguide dispersion on the group index was also found to be much smaller than that of the material dispersion of LN. It was demonstrated experimentally that the index difference induced by index dispersion strongly affects the frequency responses of ultrafast and ultralow-driving-voltage LN modulators.
Low-Noise and Low-Environmental-Impact Reflective Material for High-Density Optical Data Storage
Authors: Higuchi Takanobu , Hosoda Yasuo
Published: November 2006

We designed a new reflective material for high-density optical data storage to manage both recording and reproducing properties and environmental impact. We achieved suitable characteristics using an Al based alloy including two additional elements. In the case that AlPdSnO2 was applied in a Blu-ray disc (BD) type write-once disk, recording and reproducing properties equivalent to those for the conventional Ag alloy of AgPdCu were achieved. Moreover, in the case that it was applied for a BD-type read-only disk, jitter was improved compared with the conventional Al alloy of AlTi.