bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcriptional regulation of cyclophilin D by BMP/Smad signaling and its role in osteogenic differentiation
Authors: Sautchuk Rubens , Kalicharan Brianna H , Escalera-Rivera Katherine , Jonason Jennifer H , Porter George A , Awad Hani A , Eliseev Roman A
Published: May 2022

Cyclophilin D (CypD) promotes opening of the mitochondrial permeability transition pore (MPTP) which plays a key role in both cell physiology and pathology. It is, therefore, beneficial for cells to tightly regulate CypD and MPTP but little is known about such regulation. We have reported before that CypD is downregulated and MPTP deactivated during differentiation in various tissues. Herein, we identify BMP/Smad signaling, a major driver of differentiation, as a transcriptional regulator of the CypD gene, Ppif. Using osteogenic induction of mesenchymal lineage cells as a BMP/Smad activation-dependent differentiation model, we show that CypD is in fact transcriptionally repressed during this process. The importance of such CypD downregulation is evidenced by the negative effect of CypD ‘rescue’ via gain-of-function on osteogenesis both in vitro and in a mouse model. In sum, we characterized BMP/Smad signaling as a regulator of CypD expression and elucidated the role of CypD downregulation during cell differentiation.
Underwater Endoscopic Mucosal Resections of Non-ampullary Small Duodenal Tumors
Authors: Lee Jung Wook , Kim Su Jin , Choi Cheol Woong , Ryu Dae Gon
Published: May 2022

Conventional endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have been reported to be effective therapeutic options in sporadic non-ampullary duodenal tumors, but the rate of perforation is higher than that of other gastrointestinal lesions. Underwater EMR (UW EMR) has been reported to be a safe alternative to conventional EMR and ESD for superficial non-ampullary duodenal adenomas. We reviewed the medical chart and endoscopic report of patients who underwent endoscopic resection between August 2018 and February 2020. A total of 12 duodenal tumors were resected by UW EMR. The mean specimen and lesion sizes were 6.7 mm (2~16 mm) and 5.3 mm (2~10 mm), respectively. Of the 12 lesions, nine (75.0%) were located in the 2nd portion, and three (25.0%) were in the bulb. The mean procedural time was 7.8 minutes (3.2~18.7 minutes). Histologic results showed 10 dysplasia (nine low-grade, one high-grade) and two neuroendocrine tumors. UW EMR showed favorable efficacy and safety within small dysplastic lesions compared to previous studies’ results. Furthermore, it might be considered a treatment option with caution in patients with the duodenal subepithelial tumor within the third layer.
Impact analysis of keyword extraction using contextual word embedding
Authors: Khan Muhammad Qasim , Shahid Abdul , Uddin M. Irfan , Roman Muhammad , Alharbi Abdullah , Alosaimi Wael , Almalki Jameel , Alshahrani Saeed M.
Published: May 2022

A document’s keywords provide high-level descriptions of the content that summarize the document’s central themes, concepts, ideas, or arguments. These descriptive phrases make it easier for algorithms to find relevant information quickly and efficiently. It plays a vital role in document processing, such as indexing, classification, clustering, and summarization. Traditional keyword extraction approaches rely on statistical distributions of key terms in a document for the most part. According to contemporary technological breakthroughs, contextual information is critical in deciding the semantics of the work at hand. Similarly, context-based features may be beneficial in the job of keyword extraction. For example, simply indicating the previous or next word of the phrase of interest might be used to describe the context of a phrase. This research presents several experiments to validate that context-based key extraction is significant compared to traditional methods. Additionally, the KeyBERT proposed methodology also results in improved results. The proposed work relies on identifying a group of important words or phrases from the document’s content that can reflect the authors’ main ideas, concepts, or arguments. It also uses contextual word embedding to extract keywords. Finally, the findings are compared to those obtained using older approaches such as Text Rank, Rake, Gensim, Yake, and TF-IDF. The Journals of Universal Computer (JUCS) dataset was employed in our research. Only data from abstracts were used to produce keywords for the research article, and the KeyBERT model outperformed traditional approaches in producing similar keywords to the authors’ provided keywords. The average similarity of our approach with author-assigned keywords is 51%.
IL-4/IL-13 axis as therapeutic targets in allergic rhinitis and asthma
Authors: Nur Husna Siti Muhamad , Md Shukri Norasnieda , Mohd Ashari Noor Suryani , Wong Kah Keng
Published: May 2022

Allergic rhinitis (AR) is a common disorder of the upper airway, while asthma is a disease affecting the lower airway and both diseases are usually comorbid. Interleukin (IL)-4 and IL-13 are critical cytokines in the induction of the pathogenic Th2 responses in AR and asthma. Targeting the IL-4/IL-13 axis at various levels of its signaling pathway has emerged as promising targeted therapy in both AR and asthma patient populations. In this review, we discuss the biological characteristics of IL-4 and IL-13, their signaling pathways, and therapeutic antibodies against each cytokine as well as their receptors. In particular, the pleiotropic roles of IL-4 and IL-13 in orchestrating Th2 responses in AR and asthma patients indicate that dual IL-4/IL-13 blockade is a promising therapeutic strategy for both diseases.
Risk factors for falls in community-dwelling older people with mild cognitive impairment: a prospective one-year study
Authors: Chantanachai Thanwarat , Taylor Morag E. , Lord Stephen R. , Menant Jasmine , Delbaere Kim , Sachdev Perminder S. , Kochan Nicole A. , Brodaty Henry , Sturnieks Daina L.
Published: May 2022

Objective

Mild cognitive impairment (MCI) is considered an intermediate stage between normal cognitive function and dementia. Fall risk is increased in this group, but there is limited literature exploring specific fall risk factors that may be addressed in fall prevention strategies. The aim of this study was to examine risk factors for falls in older people with MCI, focusing on cognitive, psychological and physical factors.

Methods

Participants (n = 266, 45% women) were community-dwelling older people aged 70–90 years who met the criteria for MCI. Cognitive, psychological, sensorimotor and physical assessments, physical activity levels, medication use, general health and disability were ascertained at baseline. Falls were monitored prospectively for 12 months.

Results

During follow-up, 106 (40%) participants reported one or more falls. Poorer visual contrast sensitivity, increased postural sway, lower levels of weekly walking activity, higher levels of depressive symptoms and psychotropic medication use were significantly associated with faller status (≥1 falls) in univariable analyses. Of these factors, poor visual contrast sensitivity, increased postural sway and psychotropic medication use were found to be significant independent predictors of falls in multivariable analysis while controlling for age and sex. No measures of cognitive function were associated with falls.

Conclusions

Poor visual contrast sensitivity, impaired balance and psychotropic medication use predicted falls in community-dwelling people with MCI. These risk factors may be amenable to intervention, so these factors could be carefully considered in fall prevention programs for this population.
Machine Learning Load Balancing Techniques in Cloud Computing: A Review
Authors: Muchori Juliet Gathoni , Mwangi Peter Maina
Published: May 2022

Load balancing (LB) is the process of distributing the workload fairly across the servers within the cloud environment or within distributed computing resources. Workload includes processor load, network traffic and storage burden. LB’s main goal is to spread the computational burden across the cloud servers to ensure optimal utilization of the server resources. Cloud computing (CC) is a rapidly growing field of computing that provides computing resources as a product over the internet. This paper focuses on the issues within Cloud Load Balancing (LB) that have attracted research interest. The paper also mainly focused on uncovering machine learning models used in LB techniques. The most common algorithms in the reviewed papers included Linear Regression, Random Forest classifier (RF) Artificial Neural Network (ANN), Convolutional Neural Network (CNN) and Long-Short Term Memory- Recurrent Neural Network (LSTM -RNN). The criteria for LB technique was identified through performance metrics like throughput, response time, migration time, fault tolerance and power saving. The paper adjourns by identifying research gaps found in the reviewed literature.
A Survey of Awareness of Social Engineering Attacks to Information Security Management Systems: The Case of Kibabii University Kenya
Authors: Mbuguah Samwel Mungai , Otibine Tobias Okumu
Published: May 2022

Computer based systems are socio-technical systems in nature. The security of the system depends both on technical aspect and also social aspect. The social aspect refers to people in contact with system commonly referred to as wetware. To attack the system you may consider to target the technical or wetware. Social engineering is based on exploiting human traits that make human susceptible to these attacks. The aim of this paper was establish how aware the staff of Kibabii University were of these attributes and how these attributes could be used by social engineers to penetrate the Information Security Management systems at the institution. A survey research was adopted with a questionnaire being developed using Google application, and was administered online to all staff members of Kibabii University. A descriptive analysis was carried out on feedback. The finding was that to a large extent the sampled staff are aware of these traits but there is need for awareness training to enhance the information security management system of Kibabii University
AN INTEGRATED INFRASTRUCTURE PRIORITIZATION MODEL: CASE STUDY OF TRIPOLI, LEBANON
Authors:   University of Balamand Lebanon, Baroudi Nadia , El-Zahab Samer ,   University of Balamand Lebanon, Semaan Nabil ,   University of Balamand Lebanon, Al-Sakkaf Abobakr ,   Concordia University Canada, Abdelkader Eslam Mohammed ,   Cairo University Egypt
Published: May 2022

This paper introduces a novel non-linear weighting model to evaluate the different aspects of infrastructure. In this regard, three approaches are presented to compute the percents of infrastructure indicators, namely analytical hierarchy process, Shannon entropy and fuzzy set theory. A unified weighting model is then proposed to aggregate the weighting vectors obtained from the three approaches. The developed model is designed to model the feedback of the experts, actual condition of the infrastructure and encountered uncertainties. Results highlighted that water has the highest relative importance with 52.65% followed by electricity with 34.12% while telecommunication has the least relative importance with 2.69%. To apply a more practical sense to the proposed framework, a sample assessment of the Lebanese city of Tripoli’s civil infrastructure was carried out in this paper. The developed model is expected to support planners and policymakers with a platform that enables them to efficiently evaluate the infrastructure’s condition
Hematological Parameters and Short Term Clinical Outcome after ST-elevation Myocardial Infarction
Authors: Nemr Ahmed Mohamed , Maria Dina A. , Khalel Sameh Samir , Elsetiha Mohamed Elsayed
Published: May 2022

Background: ST-Elevation myocardial infarction is a major public health problem and a leading cause of death both in developed and developing countries. The values of hematological biomarkers were evaluated as predictors of in hospital mortality and complications, in patients with acute coronary syndromes (ACS). This study aimed to draw a relationship between different hematological parameters and short-term clinical result in STEMI cases treated by primary percutaneous coronary intervention.

Methods: This prospective research involved 100 participants that had a STEMI and were receiving primary PCI and they were subjected to detailed history, general and local examination, resting surface ECG, baseline laboratory tests, reperfusion, transthoracic echocardiogram and follow up of clinical outcome.

Results: After STEMI, there was not significantly different between cases with low and high NLR (P <0.4). There was significantly different between cases with low and high NLR after STEMI, low and high MPV [in heart failure, death and rehospitalization] and after STEMI, in diabetic patients and in NLR between low and high MPV groups after STEMI (P < 0.05), there was no significant statistical difference between patients with low and high PDW and after STEMI. LVEF were significant less in participants had MACE (P <0.036). In stepwise multivariate regression analysis of hematological parameters, NLR and MPV were significant predictive factors of MACE (P < 0.05).

Conclusions: Hematological and coagulation parameters may be utilized as diagnostic and prognostic indicators. Early risk classification enables doctors to closely monitor and treat high-risk patients, as well as schedule them for regular follow-ups, helping to the reduction of mortality.
A Universidade Pública Mergulhada no Virtual: o que nos diz o Congresso 2020 – Virtual da UFBA?
Authors: Benevides Tânia Moura , Pimenta Lídia Boaventura
Published: May 2022

Com o pressuposto de que a vida pós-pandemia não será como antes, o objetivo do artigo é evidenciar a contribuição do Congresso UFBA 2020 – Virtual, como suporte ao desenvolvimento do ensino na instituição universitária, mediante o uso das Tecnologias Digitais de Informação e Comunicação (TDIC). O período atual experimentado pelas sociedades resultante da pandemia em decorrência da COVID-19 revelou a necessidade de se pensar em atividades acadêmicas remotas, via mediação tecnológica. Nesta linha, o presente texto relata a experiência de participantes no referido Congresso, o qual evidenciou à comunidade acadêmica a possibilidade de integração virtual, com o uso da TDIC no ambiente educacional.
Social semiotics and memory in contemporary Jewish American fiction
Authors: Medeiros Ramos Aline
Published: May 2022

Despite being largely influenced by Israeli literature, contemporary Jewish American writers rarely draw upon Sephardic culture. This indicates a detachment from questions like the political ones Israeli writers emphasize, and points towards a tendency tofocus on the search for identity in a new country. The aim of this paper is to take a semiotic approach in examining this phenomenon from the standpoint of the Hebraism of American culture. I will take into account concepts of social semiotics to expand the analysis of discursive praxis, focusing also on extra and pre-textual elements. This will ultimately lead us to matters of memory, immigration, filiation and search for a national and cultural identity, which, in turn, must be seen from a historical viewpoint that cannot be set apart from discourse analysis itself.
Las razones de Manuel. Interpretaciones ideológicas para no “responder al mandato” de la tradición política familiar
Authors: Kneeteman Gastón
Published: May 2022

El presente trabajo, procurará reconocer la preponderancia que hechos relevantes de la historia argentina adquieren en la historia política, familiar y personal de los sujetos. En este sentido, se tendrá en cuenta la eficacia social de las tramas de identidades y relaciones personalizadas en la producción y actualización de formas de interacción política, buscando reconocer qué vínculos existen entre "la política" y situaciones que los actores definen como formando parte del universo social de la "familia", la "amistad", la "vecindad", la "religión". Para esto trabajaré, concretamente, sobre aquellas instancias de la historia nacional que “aparecen”, en el relato de Manuel (nuestro informante), produciendo un corte entre la “tradición política familiar”, de la cual proviene y su propia versión e interpretación sobre la historia y la política.
Primary sequence and post‐transcriptional modification pattern of an unusual mitochondrial tRNAMet from Tetrahymena pyriformis
Authors: Schnare Murray N. , Greenwood Spencer J. , Gray Michael W.
Published: July 2002

In a previous investigation of the rDNA region in Tetrahymena pyriformis mitochondrial DNA, we identified a putative tRNAMet gene [Heinonen et al. (1987) J. Biol. Chem. 262, 2879–2887]. On the basis of Northern hybridization analyses, we suggested that this gene is expressed, even though the resulting tRNA would be unusually small and have an atypical dihydrouridine stem‐loop domain. We report here the complete nucleotide sequence and post‐transcriptional modification pattern of this tRNAMet, confirming its predicted primary structure and supporting the view that this structurally aberrant species functions in translation in T. pyriformis mitochondria.
A cytochrome c–GFP fusion is not released from mitochondria into the cytoplasm upon expression of Bax in yeast cells
Authors: Roucou Xavier , Prescott Mark , Devenish Rodney J , Nagley Phillip
Published: July 2002

To study Bax‐induced release of cytochrome c in vivo, we have expressed a cytochrome c–GFP (green fluorescent protein) fusion in Saccharomyces cerevisiae cells null for the expression of the endogenous cytochrome. We show here that cytochrome c–GFP is efficiently localised to mitochondria and able to function as an electron carrier between complexes III and IV of the respiratory chain. Strikingly, while natural cytochrome c is released into the cytoplasm upon expression of Bax, the cytochrome c–GFP fusion is not. Nevertheless, cells co‐expressing Bax and the cytochrome c–GFP fusion die, indicating that mitochondrial release of cytochrome c is not essential for cell death to occur in yeast. The failure to release cytochrome c–GFP is presumed to arise from increased bulk due to the GFP moiety. We propose that in intact yeast cells, Bax‐induced release of cytochrome c into the cytoplasm occurs through a selective pore and not as a consequence of the non‐specific breakage of the mitochondrial outer membrane.
Human septin–septin interaction: CDCrel‐1 partners with KIAA0202
Authors: Bläser Susanne , Jersch Katrin , Hainmann Ina , Wunderle Daniela , Zgaga-Griesz Andrea , Busse Anja , Zieger Barbara
Published: July 2002

Septins are evolutionary conserved cytoskeletal GTPases forming heteropolymer complexes involved in cytokinesis and other cellular processes. CDCrel‐1 (cell division cycle related‐1) is a recently cloned and characterized human septin which is highly expressed in non‐dividing cells, such as neurons. Using a yeast two‐hybrid system we demonstrate that CDCrel‐1 partners with another uncharacterized human septin, KIAA0202. The interaction of CDCrel‐1 and KIAA0202 was confirmed in the human leukemia cell line K‐562 using pull‐down assays with a KIAA0202–glutathione S‐transferase fusion protein and by immunoprecipitation of the CDCrel‐1–KIAA0202 complex with an anti‐KIAA0202 antibody. Expression studies of the two human septins revealed a concomitant expression of both proteins in certain cells.
Striking the Federal Bargain in Russia: Comparative Regional Government Strategies
Authors: Dowley Kathleen M.
Published: July 2002

The central research goals of this article are to classify and explain the positions of the 89 state “governors” of Russia with regard to the most desirable federal division of power. The state governors are classified along a 5-item autonomy index based on events data and content analysis of their speeches, declarations, petitions, threats and actions from 1991–1995 as reported in two regional sources. Theoretical propositions derived from four schools of thought (essentialism, instrumentalism, relative deprivation and resource mobilization) are tested to discover which, if any, provide useful insights into the preferences and behavior of regional elites in Russia. In the end, a combined model that synthesizes elements of the above is shown to be most useful in explaining variation in elite positions.
Clinical trials update: highlights of the scientific sessions of The American College of Cardiology 2002: LIFE, DANAMI 2, MADIT‐2, MIRACLE‐ICD, OVERTURE, OCTAVE, ENABLE 1 & 2, CHRISTMAS, AFFIRM, RACE, WIZARD, AZACS, REMATCH, BNP trial and HARDBALL
Authors: Coletta Alison , Thackray Simon , Nikitin Nikolay , Cleland John G.F.
Published: July 2002

This article continues a series of reports updating recent research developments of particular interest to personnel involved in the treatment and management of patients with heart failure. This is a summary of selected presentations made at the American College of Cardiology 51st Annual Scientific Session held in Atlanta on 17–20 March 2002. Reports of the following clinical studies are included: LIFE, DANAMI 2, MADIT‐2, MIRACLE‐ICD, OVERTURE, OCTAVE, ENABLE 1 & 2, CHRISTMAS, AFFIRM, RACE, WIZARD, AZACS, REMATCH, BNP trial and HARDBALL.
Latex Particles with Thermo‐Flocculation and Magnetic Properties for Immobilization of α‐Chymotrypsin
Authors: Chen Jyh‐Ping , Su Da‐Rong
Published: July 2002

Core‐shell‐type latex particles composed of styrene, N‐isopropylacrylamide (NIPAAm), and N‐acryloxysuccinimide (NAS) were synthesized by surfactant‐free emulsion polymerization. The latex particles show thermo‐flocculation behavior due to the presence of temperature‐sensitive monomer NIPAAm and could be used for immobilization of α‐chymotrypsin through covalent bonding with the reactive ester groups of NAS. Enzyme recycle could be accomplished in this immobilized enzyme system by sedimentation of the thermo‐flocculated latex particles in 20 min at 30 °C by raising the salt (NaCl) concentration to 0.5 M. To further enhance the sedimentation rate, ultrafine magnetite particles were prepared and included during polymerization to produce magnetic temperature‐sensitive latex particles (MTLP), which could be recovered 6 times faster after thermo‐flocculation by applying a low magnetic field. However, a higher salt concentration was necessary to flocculate the MTLP under the same condition as a result of its increased surface hydrophilicity, which originates from different polymerization conditions and the incorporation of magnetite. The immobilized enzyme shows high activity even against macromolecular substrates (hemoglobin and casein) owing to limited diffusion resistance, with full activity retention for nonmagnetic latex but one‐half reduction in activity if the magnetic property was introduced. Optimal enzyme immobilization pH and enzyme loading were determined, and properties of the immobilized enzyme were characterized. The immobilized enzyme was used in 10 repeated batch hydrolyses of casein with successive flocculation/dispersion cycles and showed less than 15% activity decrease at the end. Overall, introducing the magnetic property to the latex could effectively enhance the solid‐liquid separation rate after thermo‐flocculation and maintain enzyme activity after repeated use but adversely influence the activity of the immobilized enzyme.
Structure–bioactivity of C‐terminal pentapeptide of osteogenic growth peptide [OGP(10–14)]
Authors: Chen Y. ‐C. , Bab I. , Mansur N. , Namdar‐Attar M. , Gavish H. , Vidson M. , Muhlrad A. , Shteyer A. , Chorev M.
Published: July 2002

The amino acid sequence of osteogenic growth peptide (OGP) consists of 14 residues identical to the C‐terminal tail of histone H4. Native and synthetic OGP are mitogenic to osteoblastic and fibroblastic cells and enhance osteogenesis and hematopoiesis in vivo. The C‐terminal truncated pentapeptide of OGP, H‐Tyr‐Gly‐Phe‐Gly‐Gly‐OH [OGP(10–14)], is a naturally occurring osteoblastic mitogen, equipotent to OGP. The present study assesses the role of individual amino acid residues and side chains in the OGP(10–14) mitogenic activity which showed a very high correlation between osteoblastic and fibroblastic cell cultures. Truncation of either Tyr10 or its replacement by Ala or d‐Ala resulted in substantial, but not complete, loss of activity. Nevertheless, only a small loss of activity was observed following removal of the Tyr10 amino group. No further loss occurred consequent to the monoiodination of desaminoTyr10 on meta‐position. However, a marked decrease in proliferative activity followed removal of the Tyr10 phenolic or the Phe12 aromatic group. Loss of activity of a similar magnitude also occurred subsequent to replacing Gly11 with l‐ or d‐Ala. Approximately 50% loss of mitogenic activity occurred subsequent to truncation of Gly14 or blocking the C‐terminal group as the methyl ester. All other modifications of the C‐terminus and l‐ or d‐Ala substitution of Gly13 resulted in 70–97% decrease in activity. Collectively, these data suggest that the integrity of the pharmacophores presented by Tyr and Phe side chains, as well as the Gly residues at the C‐terminus, are important for optimal bioactivity of OGP(10–14).
Allergy to grape: A case report
Authors: Rodríguez Angel , Trujillo María Jesús , Matheu Victor , Baeza María Luisa , Zapatero Lidia , Martínez Maribel
Published: July 2002

We report a case of a 5‐year‐old child who suffered an oral allergy syndrome and lip angiedema after eating grapes. We obtained a positive prick test with commercial grape extract and a positive prick‐by‐prick test with pulp and peel of fresh white grape (Moscatel variety) and pulp and peel of blue grape. Sodium dodecyl sulphate–polyacrylamide gel electrophoresis followed by immunoblotting revealed specific immunoglobulin E (IgE) antibodies in the patient's serum against a 94,000 molecular‐weight antigenic band. Lip open challenge was positive.
Clinical drug‐resistant nodular sclerosing Hodgkin's lymphoma is associated with decreased bcl‐2 expression in the surrounding lymphocytes and with increased bcl‐2 expression in the Reed–Sternberg cells
Authors: Van Spronsen D J , Peh S C , Vrints L W , Van Imhoff G W , Poppema S
Published: July 2002

Identification of patients with Hodgkin's lymphoma who are primary refractory to chemotherapy will have great impact on treatment planning. Several studies have indicated that up‐regulation of the bcl‐2 proto‐oncogene expression in non‐Hodgkin's lymphoma can cause resistance to chemotherapeutic drugs. For this reason we investigated the relationship between expression of bcl‐2, the pro‐apoptotic protein Bax and MIB‐1 with clinical drug‐resistance in Hodgkin's lymphoma

Methods and results: 

Seven patients with nodular sclerosis Hodgkin's lymphoma under 40 years of age, who failed to achieve complete remission upon primary chemotherapy and 10 matched patients who did achieve complete response were selected from the Eindhoven Cancer Registry. Tissue sections from both groups of patients were stained for bcl‐2, Bax and MIB‐1. In the non‐responding patients Reed–Sternberg cells expressed bcl‐2 more frequently using a cut‐off point of < 25% to indicate negative cells (P = 0.04), whereas no differences were observed in the expression of Bax and MIB‐1. In non‐responding patients the lymphocytes surrounding Reed–Sternberg cells expressed bcl‐2 less frequently (P = 0.002), using a cut‐off point of < 25%, whereas no difference was observed in the expression of Bax and MIB‐1.

Conclusion: 

A high percentage of Reed–Sternberg cells expressing bcl‐2 protein and a low expression of bcl‐2 protein in the surrounding lymphocytes is associated with treatment‐failure, and subsequent poor survival in young patients with nodular sclerosing Hodgkin's lymphoma. These results need further validation in larger studies.
Agricultural land‐use in China: a comparison of area estimates from ground‐based census and satellite‐borne remote sensing
Authors: Frolking Steve , Xiao Xiangming , Zhuang Yahui , Salas William , Li Changsheng
Published: July 2002

We compare estimates of total cropland area, paddy rice area, and irrigated cropland area in China from land cover maps derived from optical remote sensing in 1992–93 (1‐km resolution NOAA AVHRR) and county‐level agricultural census data for 1990. At national, regional, provincial, and county scales, the total cropland area estimated by remote sensing is 50–100% higher than reported in the agricultural census. For topographically flat North and Central China, there is a high correlation between county‐level cropland area estimates by the two approaches. For other regions, the correlation between remote sensing and agricultural census cropland area is much weaker. Throughout China, there is only moderate to weak correlation between remote sensing‐based and census‐bases estimates of paddy rice area and total irrigated cropland area. It is likely that the census data underestimates and the remote sensing overestimates the actual cropland area. These uncertainties in agricultural land cover estimates will contribute to uncertainty in any large‐scale biogeochemical analyses.
Ectomycorrhizal fungal communities in late‐successional Swedish boreal forests, and their composition following wildfire
Authors: JONSSON LENA , DAHLBERG ANDERS , NILSSON MARIE‐CHARLOTTE , ZACKRISSON OLLE , KÅRÉN OLA
Published: July 2002

This study was conducted to evaluate the effects of wildfires on ectomycorrhizal (EM) fungal communities in Scots pine (Pinus sylvestris) stands. Below‐ and above‐ground communities were analysed in terms of species richness and evenness by examining mycorrhizas and sporocarps in a chronosequence of burned stands in comparison with adjacent unburned late‐successional stands. The internal transcribed spacer (ITS)‐region (rDNA) of mycobionts from single mycorrhizas was digested with three restriction enzymes and compared with an ITS–restriction fragment length polymorphism (RFLP) reference database of EM sporocarps. Spatial variation seemed to be more prominent than the effects of fire on the EM fungal species composition. Most of the common species tended to be found in all sites, suggesting that EM fungal communities show a high degree of continuity following low‐intensity wildfires. Species richness was not affected by fire, whereas the evenness of species distributions of mycorrhizas was lower in the burned stands. The diversity of EM fungi was relatively high considering that there were only three EM tree species present in the stands. In total, 135 EM taxa were identified on the basis of their RFLP patterns; 66 species were recorded as sporocarps, but only 11 of these were also recorded as mycorrhizas. The species composition of the below‐ground community of EM fungi did not reflect that of the sporocarps produced. EM fungal species present in our ITS–RFLP reference database accounted for 54–99% of the total sporocarp production in the stands, but only 0–32% of the mycorrhizal abundance.
The Evolution of Female Coyness – Trading Time for Information
Authors: Wachtmeister Carl‐Adam , Enquist Magnus
Published: July 2002

Females in socially monogamous species require a period of courtship before they start to reproduce. When female reproductive success depends on male assistance, such ‘coy’ behaviour might have evolved in response to male philandering. In this paper, we use a dynamic optimization model to demonstrate that female coyness can be maintained during evolution (provided that a female is able to reject a male and find a new one) if two conditions are met. First, both faithful and philandering males must be present. Second, a female must be able to learn more about a male’s intention by spending time with him. In our model the optimal duration of coyness is a trade‐off between the benefit of waiting and gaining information about the male partner and the cost of postponing the onset of reproduction. This trade‐off is influenced by several factors, such as the time needed to find a male, the level of male philandering and the possibility of detecting these males, the decline of the reproductive success with time and the disadvantage of reproducing with a philandering male.
SINGLE‐ VERSUS MULTIPLE‐DOSE ANTIBIOTICS PROPHYLAXIS FOR CARDIAC SURGERY
Authors: Bucknell Sarah J. , Mohajeri Morteza , Low Jill , Mcdonald Malcolm , Hill David G.
Published: July 2002

Background: This study was carried out to determine if single‐dose antimicrobial prophylaxis is sufficient for cardiac surgery.

Methods: The study was a prospective non‐randomized trial of 353 consecutive patients undergoing cardiac surgery. Group A (n = 151) received 48 h of prophylaxis and Group B (n = 202) received a single dose. Cephazolin was used in all patients except those at high risk from methicillin‐resistant Staphylococcus aureus (MRSA) who received teicoplanin and timentin.

Results: There was an overall in‐hospital infection rate of 2.8%. There was no significant difference in rate or type of infection between the two groups.

Conclusions: An in‐hospital infection rate of 2.8% compares favourably with other reported series. Single‐dose antimicrobial prophylaxis is as effective as a 48‐h regimen. Targeting high‐risk groups is effective.
Percutaneous ultrasound‐guided thrombin injection for coagulation of post‐traumatic pseudoaneurysms
Authors: D'Achille Adam , Sebben Ruben A , Davies Roger P
Published: July 2002

Most peripheral pseudoaneurysms are iatrogenic or, less commonly, post‐traumatic. Pseudoaneurysms are associated with characteristic findings of a pulsatile palpable mass and an audible to and fro murmur. The diagnosis can be easily confirmed using colour duplex ultrasound. A successful treatment for the coagulation of pseudoaneurysms as an alternative to ultrasound‐guided manual compression is described. The method involves ultrasound‐guided direct percutaneous injection of a small quantity of thrombin through a fine needle. This technique is simple and effective, resulting in rapid occlusion of the pseudoaneurysm. Two cases are reported.
Effect of Slash‐and‐Burn Shifting Cultivation on Rainforest Birds in Mizoram, Northeast India
Authors: Raman T. R. Shankar
Published: July 2002

Abstract: Slash‐and‐burn shifting cultivation, or jhum, the predominant form of agriculture in the hill tracts of northeast India, is believed to have caused considerable loss of forest cover in the species‐rich tropical rainforests of the region. In this study I sought to understand how rainforest bird communities are affected by shifting cultivation in Mizoram State. I studied bird occurrence and abundance patterns in secondary successional and mature tropical rainforests in a shifting‐cultivation habitat mosaic in Dampa Tiger Reserve. To compare replicate sites in fallows aged 1, 5, 10, 25, and 100 years with undisturbed primary forest, I used systematic strip‐transect sampling over the winter and early summer ( breeding) seasons during 1994–1995. Many forest bird species, especially those with ranges restricted to northeast India, declined in abundance or disappeared in successional fallows that had regenerated for ≤10 years. Birds that colonized or increased in abundance in regrowth habitats were mainly common and widespread species of open‐country and secondary‐forest habitats, and of low importance for conservation. Primary forest was the main habitat for specialized forest birds, intrinsically rare species, and elevational migrants. Although protection and conservation of relatively undisturbed mature forests is imperative in the core area of the reserve, management in the buffer zone for long‐rotation shifting cultivation (>10‐year cycles) instead of plantation of monocultures may be important until alternate means of livelihood are available to cultivators.
High-speed analog spatial light modulator using a hydrogenated amorphous silicon photosensor and an electroclinic liquid crystal
Authors: Abdulhalim I. , Moddel G. , Johnson K. M.
Published: July 2002

A high-speed optically addressed spatial light modulator is described which uses the electroclinic effect in chiral smectic A liquid crystals with a p-i-n photodiode of hydrogenated amorphous silicon (a-Si:H). The near microsecond response time is a function of the liquid-crystal mixture and temperature. We present and analyze optical modulation measurements of a device which exhibits a response time of 40 μs at 29 °C and 4 μs at 50 °C. The optical response is continuous and linear with electric field and write-light intensity, allowing for grey level applications.
Facet reflection independent, single longitudinal mode oscillation in a GaAlAs/GaAs distributed feedback laser equipped with a gain-coupling mechanism
Authors: Nakano Yoshiaki , Luo Yi , Tada Kunio
Published: July 2002

By loading periodic loss perturbation into a GaAlAs/GaAs distributed feedback laser, we have realized complete single longitudinal mode oscillation which is hardly disturbed by cleaved facet reflection. Our coupled-mode analysis explains this empirical result well.
Approximate theory of highly absorbing polymer ablation by nanosecond laser pulses
Authors: Furzikov N. P.
Published: July 2002

Surface interference, nonlinearly saturated instability of laser-induced thermodestruction, and subsequent oscillation of absorption mode permit the description of analytical ablation thresholds and depths per pulse of polymers having high absorption at laser wavelengths, e.g., polyimide and poly(ethylene terephtalate). Inverse problem solution for polycarbonate and ablation invariant designing are also realized.
Recovery of 90 K superconductivity in transition-metal-doped Y-Ba-Cu-O
Authors: Kammlott G. W. , Tiefel T. H. , Jin S.
Published: July 2002

Most of the transition metal elements incorporated into the lattice of YBa2Cu3O7−δ are known to severely suppress the superconducting transition temperature. In this work, we show that an essentially complete recovery of the 90 K superconductivity can be achieved by partial melt processing of the material doped with Zr, Ta, Ti, Pt, Rh, and Re, which is attributed to second phase particles draining the dopant elements away from the matrix. Such a full recovery of Tc is not obtained in the case of Nb, V, Ni, Fe, Co, Pd, and Ru. The results are of technological interest in view of the need for nonpoisonous, high melting point substrate, clad or core materials desirable for melt processing of Y-Ba-Cu-O.
In situ single chamber laser processing of YBa2Cu3O7−δ superconducting thin films on Si (100) with yttria-stabilized zirconia buffer layers
Authors: Tiwari P. , Kanetkar S. M. , Sharan S. , Narayan J.
Published: July 2002

In situ pulsed excimer laser processing of high Tc YBa2Cu3O7−δ films on Si (100) substrates with yttria-stabilized zirconia (YSZ) buffer layers, has been carried out for the first time using a multitarget deposition system. Both YSZ and YBa2Cu3O7−δ layers were deposited sequentially using a KrF excimer laser (λ=248 nm) at substrate temperature of 650 °C. The morphology and structure of the buffer layers and YBa2Cu3O7−δ films were determined using x-ray diffraction and transmission electron microscopy techniques. The superconducting transition temperature Tc (onset) of 90 K and Tc0 (zero resistance) of 82 K were achieved for YBa2Cu3O7−δ thin films on Si with YSZ buffer layers. An interesting result of this study was that good quality, highly textured YBa2Cu3O7−δ films with the c axis perpendicular to the substrate could be grown on single crystal as well as polycrystalline textured YSZ layers deposited on silicon substrates.
Novel superlattice in a selectively doped wide parabolic quantum well with a modulated potential
Authors: Jo J. , Santos M. , Shayegan M. , Suen Y. W. , Engel L. W. , Lanzillotto A-M.
Published: July 2002

We report the realization of a novel superlattice which contains a high mobility (≂ 1.1×105 cm2/V s at 4 K) degenerate electron system. The structure consists of a wide, undoped AlxGa1−xAs well bounded by undoped (spacer) and doped layers of AlyGa1−yAs (y≳x) on both sides. The alloy composition in the well (x) is graded in such a way as to result in a parabolic potential with an additional sinusoidal modulation superimposed on it. Once transferred into this well, the electrons screen the parabolic potential and an electron system with a modulated charge density is obtained. We present self-consistent quantum mechanical calculations of the electronic system, and report our characterization of the structure by secondary-ion mass spectrometry and magnetotransport measurements.
LaSrGaO4 substrate gives oriented crystalline YBa2Cu3O7−y films
Authors: Hontsu S. , Ishii J. , Kawai T. , Kawai S.
Published: July 2002

As-grown YBa2Cu3O7−y (YBCO) thin films of 70 nm thickness have been prepared on LaSrGaO4(001), (100), and (110) single-crystal substrates at 700 °C using ArF laser ablation deposition. The c-axis oriented thin films with smooth surface morphology are obtained on LaSrGaO4 (001) and (100) substrates. The zero resistance temperatures (Tc) of the films on the (001) and (100) substrates are 90.0 K, and 88.1 K, respectively. On the (110) substrate, (110) YBCO planes grow epitaxially. The resistance perpendicular to the c axis in this film is 1/3 of that parallel to the c axis, showing Tc⊥=85.9 K and Tc∥=84.4 K, respectively. These results suggest that a LaSrGaO4 substrate having a low dielectric constant is an excellent substrate for the epitaxial growth and device application of high-Tc YBa2Cu3O7−y superconducting films.
Observation of a new surface mode on a fluid-saturated permeable solid
Authors: Nagy Peter B.
Published: July 2002

Almost ten years ago, S. Feng and D. L. Johnson predicted the presence of a new surface mode on a fluid/fluid-saturated porous solid interface with closed surface pores [J. Acoust. Soc. Am. 74, 906 (1983)]. We found that, due to surface tension, practically closed-pore boundary conditions can prevail at an interface between a nonwetting fluid (e.g., air) and a porous solid saturated with a wetting fluid (e.g., water or alcohol). Surface wave velocity and attenuation measurements were made on alcohol-saturated porous sintered glass at 100 kHz. The experimental results show clear evidence of the new ‘‘slow’’ surface mode predicted by Feng and Johnson.
Investigation of excimer laser ablation of ceramic and thin film Y-Ba-Cu-O using nanosecond photoacoustic techniques
Authors: Dyer P. E. , Farrar S. , Key P. H.
Published: July 2002

Nanosecond photoacoustic measurements of excimer laser ablated ceramic and thin film Y-Ba-Cu-O superconductors are reported that provide information on the ablation timescale threshold and surface pressure. Results for the surface pressure are found to be inconsistent with a simple surface vaporization model, suggesting that a different removal mechanism is operative. The outline of an alternative mechanism based on the concept of explosive removal is put forward.
Epitaxial growth of lithium niobate thin films from a single-source organometallic precursor using metalorganic chemical vapor deposition
Authors: Wernberg Alex A. , Gysling Henry J. , Filo Albert J. , Blanton Thomas N.
Published: July 2002

Lithium niobate thin films were deposited on (0001) sapphire using metalorganic chemical vapor deposition. An organometallic compound, formed by reaction of lithium dipivaloylmethanate and niobium(V) ethoxide, was used as a single-source precursor. The epitaxial nature of the films was established by x-ray diffraction and Rutherford backscattering analyses (RBS).
Auger recombination in strained and unstrained InGaAs/InGaAsP multiple quantum-well lasers
Authors: Fuchs G. , Schiedel C. , Hangleiter A. , Härle V. , Scholz F.
Published: July 2002

We report the determination of the Auger recombination coefficient in strained and unstrained InGaAs/InGaAsP/InP separate-confinement multiple quantum-well laser structures. For a temperature of 300 K and a well width of 100 Å, we find an Auger coefficient of C=1.0×10−28 cm6 s−1, independent of strain and only weakly dependent on temperature. These properties of the Auger coefficient indicate the dominance of phonon-assisted Auger recombination. Our model calculations based on a six-band kp theory explain the experimentally found dependency on temperature and strain. The consequences on laser performance are discussed.
External modulation of intense relativistic electron beams with spatial and velocity inhomogeneities
Authors: Serlin V. , Friedman M.
Published: July 2002

A new mechanism using a relatively low power rf source to modulate an intense relativistic electron beam was investigated. The electron beam, which had spatial and velocity inhomogeneities, interacted with two coaxial cavities, one of which was loaded with rf energy from an external generator, at a frequency of 3.5 GHz. This interaction led to an energy feedback mechanism between the cavities via reflexing electrons, resulting in a large and stable amplitude current modulation.
Superconductor-insulator-superconductor tunneling in Ba1−xKxBiO3 grain boundaries
Authors: Kussmaul A. , Hellman E. S. , Hartford E. H. , Tedrow P. M.
Published: July 2002

We have prepared single grain boundaries of the superconductor Ba1−xKxBiO3 by growing epitaxial thin films of this compound on SrTiO3 bicrystal substrates. The four-terminal current-voltage characteristics of the grain boundaries showed clear superconductor- insulator-superconductor (SIS) tunneling behavior. The leakage at zero bias was smaller than 0.3% at 4.2 K. The differential conductance displayed sharp symmetric peaks at 2Δ close to 6.5 mV. At higher bias, an increase in conductance proportional to V2 was observed. The temperature dependence of the conductance was found to be in qualitative accord with conventional SIS theory.
Self-limiting oxidation for fabricating sub-5 nm silicon nanowires
Authors: Liu H. I. , Biegelsen D. K. , Ponce F. A. , Johnson N. M. , Pease R. F. W.
Published: July 2002

The ability to control structural dimensions below 5 nm is essential for a systematic study of the optical and electrical properties of Si nanostructures. A combination of electron beam lithography, NF3 reactive ion etching, and dry thermal oxidation has been successfully implemented to yield 2-nm-wide Si nanowires with aspect ratio of more than 100 to 1. With a sideview transmission electron microscopy technique, the oxidation progression of Si nanowires was characterized over a range of temperature from 800 to 1200 °C. A previously reported self-limiting oxidation phenomenon was found to occur only for oxidation temperatures below 950 °C. A preliminary model suggests that increase in the activation energy of oxidant diffusivity in a highly stressed oxide may be the main mechanism for slowing down the oxidation rate in the self-limiting regime.
Nanometer-structure writing on Si(100) surfaces using a non-contact-mode atomic force microscope
Authors: Wang Dawen , Tsau Liming , Wang K. L.
Published: July 2002

Nanometer structures were written on Si(100) surfaces by use of a non-contact-mode atomic force microscope. The silicon oxide was formed beneath the tip by applying a negative bias voltage between a p+ silicon tip and the samples. The writing resolution was mainly determined by the local chemical reactions induced by the tip and a minimum line width of about 10 nm was obtained, which is close to that achieved by scanning tunneling microscope and contact-mode atomic force microscope writing.
Single-walled carbon nanotubes growing radially from YC2 particles
Authors: Zhou Dan , Seraphin Supapan , Wang Su
Published: July 2002

In the primary soot produced by arc discharge using an yttrium carbide loaded anode, bundles of single-walled carbon nanotubes (SWT) are observed, protruding radially from YC2 particles coated with graphitic multilayers. The graphitic cages separating YC2 particle and SWT bundles fall into the narrow range of 10–20 layers. The morphology of the clusters suggests a two-step growth model: The radial SWT growth pattern is first initiated by catalytic action between the YC2 droplet and the carbon in the gas phase. Second, and upon cooling, the graphitic cage starts by segregating excess carbon from the YC2 bulk, arresting further growth of SWT.