bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid binding to protofilament edge sites facilitates tip tracking of EB1 at growing microtubule plus-ends
Authors: Gonzalez Samuel J , Heckel Julia M , Goldblum Rebecca R , Reid Taylor A , McClellan Mark , Gardner Melissa K
Published: February 2024

EB1 is a key cellular protein that delivers regulatory molecules throughout the cell via the tip-tracking of growing microtubule plus-ends. Thus, it is important to understand the mechanism for how EB1 efficiently tracks growing microtubule plus-ends. It is widely accepted that EB1 binds with higher affinity to GTP-tubulin subunits at the growing microtubule tip, relative to GDP-tubulin along the microtubule length. However, it is unclear whether this difference in affinity alone is sufficient to explain the tip-tracking of EB1 at growing microtubule tips. Previously, we found that EB1 binds to exposed microtubule protofilament-edge sites at a ~70 fold faster rate than to closed-lattice sites, due to diffusional steric hindrance to binding. Thus, we asked whether rapid protofilament-edge binding could contribute to efficient EB1 tip tracking. A computational simulation with differential EB1 on-rates based on closed-lattice or protofilament-edge binding, and with EB1 off-rates that were dependent on the tubulin hydrolysis state, robustly recapitulated experimental EB1 tip tracking. To test this model, we used cell-free biophysical assays, as well as live-cell imaging, in combination with a Designed Ankyrin Repeat Protein (DARPin) that binds exclusively to protofilament-edge sites, and whose binding site partially overlaps with the EB1 binding site. We found that DARPin blocked EB1 protofilament-edge binding, which led to a decrease in EB1 tip tracking on dynamic microtubules. We conclude that rapid EB1 binding to microtubule protofilament-edge sites contributes to robust EB1 tip tracking at the growing microtubule plus-end.
Lipid discovery enabled by sequence statistics and machine learning
Authors: Christensen Priya M , Martin Jonathan , Uppuluri Aparna , Joyce Luke R , Wei Yahan , Guan Ziqiang , Morcos Faruck , Palmer Kelli L
Published: February 2024

Bacterial membranes are complex and dynamic, arising from an array of evolutionary pressures. One enzyme that alters membrane compositions through covalent lipid modification is MprF. We recently identified that Streptococcus agalactiae MprF synthesizes lysyl-phosphatidylglycerol (Lys-PG) from anionic PG, and a novel cationic lipid, lysyl-glucosyl-diacylglycerol (Lys-Glc-DAG), from neutral glycolipid Glc-DAG. This unexpected result prompted us to investigate whether Lys-Glc-DAG occurs in other MprF-containing bacteria, and whether other novel MprF products exist. Here, we studied protein sequence features determining MprF substrate specificity. First, pairwise analyses identified several streptococcal MprFs synthesizing Lys-Glc-DAG. Second, a restricted Boltzmann machine-guided approach led us to discover an entirely new substrate for MprF in Enterococcus, diglucosyl-diacylglycerol (Glc2-DAG), and an expanded set of organisms that modify glycolipid substrates using MprF. Overall, we combined the wealth of available sequence data with machine learning to model evolutionary constraints on MprF sequences across the bacterial domain, thereby identifying a novel cationic lipid.
AMMI and GGE biplot analysis for genotype × environment interactions affecting the yield and quality characteristics of sugar beet
Authors: Dang Xinwang , Hu Xiaohang , Ma Yahuai , Li Yanli , Kan Wenliang , Dong Xinjiu
Published: February 2024

Sugar beet, an important sugar crop, contributes significantly to the world’s sugar production. However, genotype–environment interactions (GEI) often affect the quality characteristics of sugar beet. Hence, understanding the effects of GEI on sugar beet quality can aid in identifying high-quality genotypes that can adapt to different environments. Traditional variance analysis can only be used to examine the yield of a variety and not its specific adaptability to specific conditions. Therefore, more comprehensive analytical methods are required to evaluate the characteristics of the variety under specific environments. Additive main effects and multiplicative interaction (AMMI) and genotype main effect and genotype × environment interaction (GGE) biplot models can be employed to comprehensively evaluate different varieties and address the drawbacks associated with a single evaluation method. Moreover, these models also allow us to explore new varieties more objectively and comprehensively. In this study, the adaptability and stability of 16 sugar beet varieties, in terms of yield and sugar content, were evaluated using AMMI and GGE biplot analysis in seven pilot projects undertaken in 2022. In the assessment of a small but significant proportion of the total GEI variance for the two qualitative traits (yield and sugar content), 80.58% of the variance was explained by the cumulative contribution of IPC1, IPC2, and IPC3. AMMI and GGE biplots clearly highlighted that KWS4207 (G3) exhibited high and stable quality. They also demonstrated that the experiments in Jalaid Banner (Inner Mongolia) (E7) were the most representative. Together, the results suggested that the comprehensive application of AMMI and GGE biplot analysis allowed for a more comprehensive, scientific, and effective evaluation of sugar beet varieties across different regions. The findings offer a theoretical basis for sugar beet breeding and could guide the rational design of experiments for testing new varieties of sugar beet.
Hypoxic bone marrow mesenchymal stem cell exosomes promote angiogenesis and enhance endometrial injury repair through the miR-424-5p-mediated DLL4/Notch signaling pathway
Authors: Xiong Zhenghua , Hu Yong , Jiang Min , Liu Beibei , Jin Wenjiao , Chen Huiqin , Yang Linjuan , Han Xuesong
Published: February 2024

Background

Currently, bone marrow mesenchymal stem cells (BMSCs) have been reported to promote endometrial regeneration in rat models of mechanically injury-induced uterine adhesions (IUAs), but the therapeutic effects and mechanisms of hypoxic BMSC-derived exosomes on IUAs have not been elucidated.

Objective

To investigate the potential mechanism by which the BMSCS-derived exosomal miR-424-5p regulates IUA angiogenesis through the DLL4/Notch signaling pathway under hypoxic conditions and promotes endometrial injury repair.

Methods

The morphology of the exosomes was observed via transmission electron microscopy, and the expression of exosome markers (CD9, CD63, CD81, and HSP70) was detected via flow cytometry and Western blotting. The expression of angiogenesis-related genes (Ang1, Flk1, Vash1, and TSP1) was detected via RT‒qPCR, and the expression of DLL4/Notch signaling pathway-related proteins (DLL4, Notch1, and Notch2) was detected via Western blotting. Cell proliferation was detected by a CCK-8 assay, and angiogenesis was assessed via an angiogenesis assay. The expression of CD3 was detected by immunofluorescence. The endometrial lesions of IUA rats were observed via HE staining, and the expression of CD3 and VEGFA was detected via immunohistochemistry.

Results

Compared with those in exosomes from normoxic conditions, miR-424-5p was more highly expressed in the exosomes from hypoxic BMSCs. Compared with those in normoxic BMSC-derived exosomes, the proliferation and angiogenesis of HUVECs were significantly enhanced after treatment with hypoxic BMSC-derived exosomes, and these effects were weakened after inhibition of miR-424-5p. miR-424-5p can target and negatively regulate the expression of DLL4, promote the expression of the proangiogenic genes Ang1 and Flk1, and inhibit the expression of the antiangiogenic genes Vash1 and TSP1. The effect of miR-424-5p can be reversed by overexpression of DLL4. In IUA rats, treatment with hypoxic BMSC exosomes and the miR-424-5p mimic promoted angiogenesis and improved endometrial damage.

Conclusion

The hypoxic BMSC-derived exosomal miR-424-5p promoted angiogenesis and improved endometrial injury repair by regulating the DLL4/Notch signaling pathway, which provides a new idea for the treatment of IUAs.
Study of the accelerated stability of natural repellents against mosquito bites that transmit endemic diseases
Authors: Cesário Vandenilso Macêdo , Chaves Davina Camelo , Rodrigues Makson Rangel de Melo , Reis Hugo da Costa , Pereira Efraim Costa , Muchave Germildo Juvenal , Dos Santos Jean Carlos , Vieira José Sebastião Cidreira
Published: February 2024

The Aedesaegypti mosquito is the vector that transmits several diseases, such as dengue, yellow fever, zika virus, and chikungunya fever. The most used control of the spread of the Aedes aegypti mosquito today is chemical insecticides. However, over time, this mosquito created resistance in response to insecticides, requiring new alternatives capable of inactivating it without harming humans and the environment. In this sense, essential oils extracted from aromatic plants are widely used in the cosmetic and pharmaceutical industries due to their availability in the Brazilian flora. They have great potential to replace chemical insecticides. This project aims to produce a repellent cream by adding glycolic extract of monkey pepper (Piper aduncum) and clove (Syzygium aromaticum.) The emulsion will be prepared in two phases, the hydrophilic and the lipophilic phase; the quality control of the cream will be carried out based on accelerated stability in terms of the parameter’s centrifugation, freezing and thawing cycles, density, spreadability, organoleptic characterization, stability at extreme temperatures and pH.
Cidades inteligentes e os indicadores urbanos de meio ambiente: uma análise de Passo Fundo-RS
Authors: Müller Letícia , Da Silva Thaísa Leal
Published: February 2024

O planejamento e gestão das cidades têm sido um grande desafio para os gestores públicos, principalmente por problemáticas e demandas relacionadas com áreas como segurança, saúde, e saneamento básico. Uma iniciativa que tem como intuito auxiliar na mitigação desses problemas é o conceito de Cidades Inteligentes, que utiliza as TICs como agentes de transformação no meio urbano. Uma das ferramentas utilizadas pelas Cidades Inteligentes, são os indicadores urbanos, que servem como subsídio para mensurar, analisar e compreender o contexto das cidades. Neste sentido, o objetivo deste artigo é analisar os indicadores urbanos de Meio Ambiente da cidade de Passo Fundo. Na metodologia, utilizou-se como referência os indicadores do Ranking Connected Smart Cities, bem como, um recorte regional das cidades de médio porte melhores classificadas no Ranking. Foram aplicados procedimentos multimédotos de coleta e levantamento de dados. Os resultados demonstram que os índices de Passo Fundo, no que diz respeito aos indicadores de Meio Ambiente, são inferiores aos das cidades analisadas, e estão distantes dos níveis tidos como ideais para tornar-se uma cidade mais inteligente e sustentável.
Frequency of Multidrug-Resistant Microorganisms Associated with Bacterial Coinfections in Hospitalized Patient with Covid-19: A Literature Review
Authors: Oliveira Maria Walcleanes Magalhães de , Prado Júlio César Sousa , Silva Martinair Santana da , Martins Maria Gleiciane de Queiroz , Barbosa Francisco Cesar Barroso
Published: February 2024

Patients with a doença do coronavírus 2019 (COVID-19) may be at risk of associated bacterial co-infections, and the involvement of multidrug-resistant (MDR) microorganisms in these cases can lead to an increase in morbidity and mortality rates. The objective of this study was to describe the frequency of the main MDR microorganisms associated with bacterial co-infections in patients hospitalized with COVID-19. To this end, we carried out a search in the PubMed and Regional Portal of the Virtual Health Library (VHL) databases, from December 2019 to September 2023, with the keywords COVID-19, co-infection and multidrug-resistant microorganism. Of the 535 articles initially found, only 14 were selected for analysis. Gram-negative bacteria were most frequently involved in bacterial co-infections in patients with COVID-19 (70%). Among these, Klebsiella pneumoniae and Acinetobacter baumannii predominated, with 85.71% and 78.57%, respectively. Among gram-positive bacteria, Staphylococcus aureus (71.42%) was the most common. Among MDR microorganisms, the prevalent species were carbapenem-resistant gram-negative bacilli (32%) and methicillin-resistant S. aureus (85.7%). Furthermore, a higher frequency of MDR microorganisms was observed in patients with COVID-19 in intensive care units (ICU). Thus, the findings of the present study indicate the need for attention to infections caused by multidrug-resistant microorganisms in critically ill patients with COVID-19.
Analysis of the Effects of Agency Costs on Financial Performance of Commercial Banks Listed at the Nairobi Securities Exchange in Mombasa County, Kenya
Authors: Otete Fredrick Oduor , Ronald Martin Onsiro
Published: February 2024

Agency costs result from a principal-agent relationship's conflicting interests.  The relationship develops because the principal may not be able to manage the business since they are technologically illiterate, numerous, and geographically spread; as a result, they hire the agent. In a commercial bank, there are various relationships that show principal agent relationships, with the most prevalent one being the link between the shareholders and the management. Agency fees are paid with the intention of aligning the agents' and principal's ambitions in order to realize the principal's overarching intentions. Therefore, the perseverance of this study was to analyze agency costs and their effects on financial performance. In this study, the agency cost on financial performance of public commercial banks was analyzed. Specific objectives were; to establish how monitoring cost affect the financial performance of quoted commercial banks in Mombasa County, to assess the effect of bonding cost on financial performance of listed commercial banks in Mombasa county, to examine the extent to which residual loss affect the financial performance of commercial banks in Mombasa county and to determine the effects of restructuring cost on financial performance of listed commercial banks in Mombasa County- directed the study. Theories supporting this study were as follows; agency theories, free cash flow and stakeholder’s theory. Descriptive design is a kind of research methodology which establishes the connection between variables. It was used in this study to identify both the broad and the detailed study goals. A census of the 10 listed commercial banks in Mombasa County was conducted as part of the work and purposive sampling was be used. This study used qualitative and quantitative methods. Validity was tested through interview while reliability was tested using Cronbach alpha. The data was analyzed using inferential statistics like regression and correlation and descriptive statistics like mean and standard deviation using the Statistical Package for Social Science (SPSS) Version 22.0. The results were presented using cross tabulation, frequency tables, and charts. Findings indicated that there was a significant impact between; monitoring cost, bonding cost and residual cost and the financial performance. Restructuring cost were determined to have a favourable impact on financial performance. Therefore, the study recommends implementing an efficient internal control system by listed commercial bank management. This will assist in cutting down on the cost of auditing, administrative costs, and wasteful and unneeded spending, Managers should be paid more and attaching monetary or share bonuses or option entitlements to particular firm performance and to adopt a type of restructuring that will align with the relevant strategy and objectives.
Exploring Agroecological Approaches for Sustainable Agriculture and Rural Development: A Comprehensive Review
Authors: Bhandari Sujan , Yadav Bishnu , Yadav Pawan Kumar , Lahutiya Vivek , Koirala Sudip
Published: February 2024

Agroecology, as an interdisciplinary field, integrates ecological principles into agricultural systems to promote sustainability. This paper examines the pivotal role of agroecological approaches in fostering sustainable agriculture and rural development. Initially concentrated on enhancing crop productivity and resilience, agroecology has evolved to encompass broader dimensions, including environmental stewardship, social equity, and economic viability. By emphasizing the sustainable use of resources and adopting diverse strategies, agroecology addresses contemporary challenges in agricultural production. This review synthesizes existing literature on the fundamental concepts and principles of agroecology, highlighting its profound implications for sustainable agriculture and rural development. By exploring agroecological approaches at various scales, from plot-level interventions to systemic changes within the food system, this paper underscores the critical linkage between agroecology and the pursuit of sustainable agricultural practices and rural prosperity.
Enhancement of Yield, Nitrogen use Efficiency, Production Economics of Fodder Oat through Selection of Appropriate Genotype and Nitrogen Fertilizer Application
Authors: Sarkar Saikat , Nanda Gangadhar , Singh Devendra , Kumar Sunil , Singh Santosh Kumar , Nath Hrishikesh
Published: February 2024

Growing fodder oat (Avena sativa L.) genotype with high yielding potential with adequate nitrogen could enhance the fodder yield and quality to bridge the gap between demand and supply of green fodder. Therefore, an experiment was performed to evaluate the effect of different genotypes and nitrogen levels on yield, nitrogen use efficiency, production economics, and agro-meteorological parameters of fodder oat at Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar. Six oat genotypes, viz., Kent, JO-07-28, OS-403, OS-6, HFO-904 and HFO-906, were sown with 40, 80 and 120 kg of nitrogen per hectare. The experiment was set up using a split-plot design, with three replications of the genotypes in the main plots and N levels in sub-plots. Results revealed that genotype JO-07-28 was significantly superior to Kent (check) with respect to green fodder yield whereas both were comparable to each other with respect to dry matter yield, crude protein content and yield. Kent showed maximum N, P and K uptake and heat use efficiency, helio-thermal and photo-thermal unit efficiency. However, genotype JO-07-28 yielded the highest net returns (Rs. 27421/ha), B:C ratio (1.85), and economic efficiency (Rs. 271/ha/day). Among other nitrogen levels, application of 120 kg N/ha recorded the maximum yields of green fodder (371 q/ha) and dry matter (91 q/ha), crude protein content and yield, N uptake, net returns (Rs. 23096/ha), B:C ratio (1.71) and economic efficiency (Rs. 231/ha/day) and  heat use efficiency (7.60), helio-thermal and photo-thermal unit efficiency which were statistically equivalent to 80 kg N/ha. Genotype JO-07-28 and HFO-904 were the most N efficient genotype in terms of partial factor productivity of N fertilizer and nitrogen utilization efficiency, respectively. Enhancement in level of N application reduced the nitrogen use efficiency.
Deciphering Genetic Diversity in Advanced Wheat Lines (Triticum aestivum L.) for Yield and Other Yield Contributing Traits Across the Locations
Authors: Kumar Amit , Jaiswal JP , Chaudhary Himanshu , Vinesh Banoth , Kumawat Shubham , Parihar Priyanka , Bhatt Babita
Published: February 2024

Twenty advanced wheat genotypes were evaluated for yield and yield-contributing traits in six field trials over two cropping seasons (Rabi 2020-21 and 2021-22) using a completely randomized block design (RBD) at two locations: the N.E. Borlaug Crop Research Centre (NEBCRC), G.B.P.U.A&T, Pantnagar, U.S. Nagar district, and the Agriculture Research Center Majhera, Nainital, Uttarakhand. The study aimed to assess genetic diversity among the genotypes via principal component analysis (PCA) and cluster analysis, offering insights into genetic variations. Three clusters were formed, with the maximum number of genotypes occurring in the second cluster. A lower p-value indicates that the clusters are statistically significant, suggesting that the observed diversity is not random. High estimates of cophenetic distance (.79) specify a high genetic distance between clusters, indicating that diverse genetic material is under study. The maximum genetic distance observed was 144.9 between genotypes G5 and G11. These findings suggest that these two genotypes are the most genetically diverse among all the studied genotypes and can be used as parents to develop high genetic variation in the studied traits. The PCA results yielded 18 principal components, with the first seven components accounting for approximately 83% of the total variance, indicating significant genetic diversity. The scree plot affirmed the robustness of the study’s results by suggesting that the first eight principal components accounted for a substantial portion of the variance.The findings of current study could be exploited in planning and execution of future breeding programme in wheat.
Analysis of Yield Stability in Diverse Rice Genotypes
Authors: Borule Taruna , Pandey Vipin Kumar , Singh Laxmi , Sathe Atul Prakash , Akanksha  , Raut Pradnya Manoj , Athira T.G.  , Rana Shivani Singh , Shori Savita , Verulkar Satish B , Banerjee Shubha
Published: February 2024

Aims/ objectives: This study aims to improve stable and sustainable rice varieties adaptable to changing climatic conditions. It involves assessing genetic variability and Genotype X Environment interaction (G x E) among 186 diverse rice genotypes. The goal is to select genotypes with high breeding value, contributing to the development of rice varieties well-suited to varying climatic conditions.
Study Design: The study employed an augmented design in a Randomized Complete Block Design (RCBD). Swarna, Madhuraj-55, Safri-17, Improved Samba Mahsuri, Thavalkannan, and IR64 checks were replicated across environments.
Place and Duration of Study: The study took place in College of Agriculture, Raipur, IGKV over two years (wet season-2020 and 2021).
Methodology: Analysis of genetic variability and G X E interaction among 186 rice genotypes. Execution of the experiment in an augmented design with a randomized complete block design. Replication of standard rice checks across different environments. Assessment of yield-attributing traits such as plant height, number of effective tillers, panicle length, number of grains per panicle, biological yield per plot, and grain yield. Evaluation of stability was done using univariate (Shukla stability variance, Wricke’s ecovalence, Kang stability statistic) and multivariate (AMMI yield stability index and GGE biplot) stability parameters. Selection of stable genotypes with high yield based on stability analyses.
Results: Significant phenotypic variation was observed in yield-attributing traits across seasons. Genetic variability and G x E interaction effect demonstrated by variable genotype performance across environments. Univariate and multivariate stability parameters (S2i, W2i, KSi, AMMI stability value, GGE biplot) were used for stability analyses. Identification of stable genotypes with high yield across environments, including IR13f167, ARC13156, IR93354, F50, Ngalongyi, Giza 178, Arc 10159, Sadajira 19-317, Arith, IR 57920-Ac 25-2-B, Pesagro 102, Mekenzie small, Nasaenge, Kula Karuppan, Vary Gony, MR 69, Kanu Dam, IRRI 123, Sativa IRGC17083-1, Kalia, and Swarna.
Conclusion: The study concludes that stability in genotype performance across diverse environments is crucial for the development of sustainable rice varieties. Genotypes with high stability and yield, as identified through stability analyses, hold potential breeding value for developing rice varieties adaptive to climate change. The stable genotypes listed, including IR13f167, ARC13156, IR93354, and others, are recommended for further breeding and development efforts to enhance rice productivity and adaptability.
Unemployment and Educational Attainment in Nigeria
Authors: Okoli Chike K. , Okaforocha Chika M. , Osang Paul , Nwokoye Ebele S.
Published: February 2024

The tragedy of jobless growth makes the increasing rate of unemployment among school leavers a cause of grave concern in Nigeria. Based on the human capital theory, this study examines the dependence of unemployment on educational attainment in Nigeria from 1990-2020 using the autoregressive bounds test approach. Data were sourced from National Bureau of Statistics (NBS), Central Bank of Nigeria (CBN) and other secondary data sources. The study employed variables such as the primary graduation rate, secondary graduation rate, tertiary graduation rate, government expenditure on education and inflation rate. Our findings show that among other factors, government expenditure on education as well as primary, secondary and tertiary graduation rates significantly brought about a reduction in unemployment in Nigeria both in the short and long run. We therefore recommend that government should increase its budgetary allocation to the education sector, as well as monitor the utilization of such funds. Government should also sensitize the public on the importance of education both on the individual and society at large.
Social representations of people with mental health problems resulting from the use of alcohol and other drugs / Representações sociais de pessoas com problemas de saúde mental decorrentes do uso de álcool e outras drogas
Authors: Da Silva Silvio Éder Dias , Fonseca Monique Pantoja , Ueda Alissa Yuki , Oliveira Márcia Aparecida Ferreira de , Rodrigues Diego Pereira , Rodrigues Diana Madeira
Published: February 2024

Objetivo: compreender as representações sociais de pessoas com problemas de saúde mental decorrentes do uso de álcool e outras drogas que frequentam os Narcóticos Anônimos. Método: trata-se de um estudo descritivo-exploratório, com enfoque qualitativo, empregando as Representações Sociais para a temática da pesquisa, em que foram implementadas as etapas do Consolidated Criteria for Reporting Qualitative Research. Resultados: as informações obtidas foram transformadas em três unidades temáticas: as Representações Sociais de pessoas com problemas de saúde mental decorrentes do uso de álcool e outras drogas; Representações Sociais de álcool e outras drogas: doença da adicção; frequentar Narcóticos Anônimos significa liberdade, uma autoavaliação e aceitação. Considerações finais: a compreensão das representações sociais e suas implicações na obtenção da abstinência, possibilita atuar mediante às especificidades de cada sujeito, partindo de uma abordagem integral considerando-se as percepções acerca de sua condição, vivências e contexto no qual está inserido.
Gas‐liquid‐fiber flow in a cocurrent bubble column
Authors: Tang Chengzhi , Heindel Theodore J.
Published: July 2005

Effects of superficial gas velocity (Ul ≤ 10 cm/s), superficial liquid velocity (Ug ≤ 10 cm/s), and fiber mass fraction (0 ≤ C ≤ 2%) on gas holdup (ϵ) and flow regime transition are studied experimentally in well‐mixed water‐cellulose fiber suspensions in a cocurrent bubble column. Experimental results show that gas holdup decreases with increasing superficial liquid velocity when fiber mass fraction and superficial gas velocity are constant. Gas holdup is not significantly affected by fiber mass fraction in the range of C < 0.4%, but decreases with increasing fiber mass fraction in the range of 0.4% ≤ C ≤ 1.5%. The mechanisms behind the influences of superficial liquid velocity and fiber mass fraction on gas holdup in a gas‐liquid‐fiber bubble column are analyzed. The effects of gas distribution methods are also explained by comparison to previous results. The axial gas holdup distribution is shown to be a complex function of superficial gas and liquid velocities and fiber mass fraction. The drift‐flux model is used to identify the flow regime transitions at different operating conditions. Three distinct flow regimes are observed when C ≤ 0.4%, but only two are identified when 0.6% ≤ C ≤ 1.5%. The superficial gas velocities at which the flow transitions from one regime to another are not significantly affected by Ul, and only slightly decrease with increasing C. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Partial oxidation of methane to synthesis gas by a microwave plasma torch
Authors: Tsai Cheng‐Hsien , Hsieh Tsung‐Hua , Shih Minliang , Huang Yuh‐Jeen , Wei Ta‐Chin
Published: July 2005

This study demonstrates a noncatalytic, low‐pressure, and room‐temperature process for methane partial oxidation into syngas by using a microwave plasma torch reactor. The experimental results showed that the elevation of the inlet O2/CH4 molar ratio, pressure, and applied power led to the outlet H2/CO molar ratios decreased from 3.32 (at O2/CH4 = 0.3, 13.3 kPa, and 160 W) to 0.81 (at O2/CH4 = 1.5, 93.3 kPa, and 600 W). At O2/CH4 = 0.5, the higher selectivity and yield of syngas, and a H2/CO molar ratio of about 2 could be obtained simultaneously. In addition, the maximum yield of syngas per unit mole of methane consumed could be achieved at a higher pressure, although a higher methane conversion was performed at a lower pressure. Based on these, this study suggests that the operating conditions of O2/CH4 = 0.5 and near atmospheric pressure (93.3 kPa) would be the most appropriate combination for converting methane into syngas. Under the conditions, the selectivities of H2 and CO reached 97.6 and 99.2%, respectively, accompanied with H2/CO = 1.97 at 600 W. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Strategies for Hydrogen Storage in Metal–Organic Frameworks
Authors: Rowsell Jesse L. C. , Yaghi Omar M.
Published: July 2005

Increased attention is being focused on metal–organic frameworks as candidates for hydrogen storage materials. This is a result of their many favorable attributes, such as high porosity, reproducible and facile syntheses, amenability to scale‐up, and chemical modification for targeting desired properties. A discussion of several strategies aimed at improving hydrogen uptake in these materials is presented. These strategies include the optimization of pore size and adsorption energy by linker modification, impregnation, catenation, and the inclusion of open metal sites and lighter metals.
Phase II study of the farnesyltransferase inhibitor lonafarnib with paclitaxel in patients with taxane‐refractory/resistant nonsmall cell lung carcinoma
Authors: Kim Edward S. , Kies Merrill S. , Fossella Frank V. , Glisson Bonnie S. , Zaknoen Sara , Statkevich Paul , Munden Reginald F. , Summey Carmen , Pisters Katherine M.W. , Papadimitrakopoulou Vali , Tighiouart Mourad , Rogatko Andre , Khuri Fadlo R.
Published: July 2005

BACKGROUND

The authors evaluated the safety, tolerability, and efficacy of treatment using lonafarnib, a novel farnesyltransferase inhibitor (FTI), in combination with paclitaxel in patients with metastatic (Stage IIIB/V), taxane‐refractory/resistant nonsmall cell lung carcinoma (NSCLC).

METHODS

Patients with NSCLC who experienced disease progression while receiving previous taxane therapy or who had disease recurrence within 3 months after taxane therapy cessation were treated with continuous lonafarnib 100 mg orally twice per day beginning on Day 1 and paclitaxel 175 mg/m2 intravenously over 3 hours on Day 8 of each 21‐day cycle.

RESULTS

A total of 33 patients were enrolled, 29 of whom were evaluable for response. Partial responses (PR) and stable disease (SD) were observed in 3 (10%) and 11 patients (38%), respectively. Thus, 48% (14 of 29) experienced clinical benefit (PR or SD). The updated and final median overall survival time was 39 weeks and the median disease progression‐free survival time was 16 weeks. The combination of lonafarnib and paclitaxel was well tolerated with minimal toxicity. Grade 3 toxicities included fatigue (9%), diarrhea (6%), and dyspnea (6%). Grade 3 neutropenia occurred in only 1 patient (3%). Grade 4 adverse events included respiratory insufficiency in 2 patients (6%) and acute respiratory failure in 1 patient (3%).

CONCLUSIONS

Lonafarnib plus paclitaxel demonstrated clinical activity in patients with taxane‐refractory/resistant metastatic NSCLC. In addition, the combination of lonafarnib and paclitaxel was well tolerated with minimal toxicity. Evaluation of this combination therapy in additional clinical trials is warranted. Cancer 2005. © 2005 American Cancer Society.
Cyclic AMP/cAMP‐GEF pathway amplifies insulin exocytosis induced by Ca2+ and ATP in rat islet β‐cells
Authors: Hashiguchi Hiroshi , Nakazaki Mitsuhiro , Koriyama Nobuyuki , Fukudome Michiyo , Aso Katsumi , Tei Chuwa
Published: July 2005

Background

Cyclic AMP (cAMP) plays a pivotal role in insulin secretion induced by incretins. The effects of the second messenger extend to many sites and there has been much controversy on the mechanisms. The aim of this study was to examine how cAMP amplified insulin exocytosis.

Methods

Rat islets were permeabilized with α‐toxin to measure insulin exocytosis in the fixed conditions of Ca2+ and ATP. The effects of several agents on insulin exocytosis were observed in perifusion experiments.

Results

Cyclic AMP enhanced the Ca2+‐induced insulin release by around 30%, independent of Ca2+ concentrations between 10 and 3000 nmol/L. A cAMP‐GEF selective cAMP analogue, 8‐(4‐chloro‐phenylthio)‐2′‐O‐methyladenosine‐3′,5′‐cyclic monophosphate, also amplified insulin release. The effect disappeared in the absence of ATP. Conversely, cAMP‐independent gradual increase in insulin release was observed with ATP. These results suggested that the site of action of cAMP‐GEF existed proximal to that of ATP. An analogue selective to PKA, N6‐Benzoyladenosine‐3′,5′‐cyclic monophosphate, had little effect. Also, a PKA‐selective inhibitor, N‐[2‐(p‐bromocinnamylamino)ethyl]‐5‐isoquinolinesulfonamide, reduced insulin releases induced by 1000 nmol/L Ca2+, but did not influence the relative increase produced by Ca2+ and cAMP.

Conclusion

Cyclic AMP potentiated Ca2+ and ATP‐induced exocytosis to a similar relative extent independent of Ca2+ concentrations. The process appeared to be mainly mediated by cAMP‐GEF. In addition, the cAMP/cAMP‐GEF pathway may enhance insulin release by replenishing the readily releasable pool. Copyright © 2005 John Wiley & Sons, Ltd.
Differential levels of tissue hypoxia in the developing chicken heart
Authors: Wikenheiser Jamie , Doughman Yong‐Qiu , Fisher Steven A. , Watanabe Michiko
Published: July 2005

Tissue hypoxia plays a critical role in normal development, including cardiogenesis. Previously, we showed that oxygen concentration, as assessed by the hypoxia indicator EF5, is lowest in the outflow tract (OFT) myocardium of the developing chicken heart and may be regulating events in OFT morphogenesis. In this study, we identified additional areas of the embryonic chicken heart that were intensely positive for EF5 within the myocardium in discrete regions of the atrial wall and the interventricular septum (IVS). The region of the IVS that is EF5‐positive includes a portion of the developing central conduction system identified by HNK‐1 co‐immunostaining. The EF5 positive tissues were also specifically positive for nuclear‐localized hypoxia inducible factor 1α (HIF‐1α), the oxygen‐sensitive component of the hypoxia inducible factor 1 (HIF‐1) heterodimer. The pattern of the most intensely EF5‐stained myocardial regions of the atria and IVS resemble the pattern of the major coronary vessels that form in later stages within or immediately adjacent to these particular regions. These vessels include the sinoatrial nodal artery that is a branch of the right coronary artery within the atrial wall and the anterior/posterior interventricular vessels of the IVS. These findings indicate that a portion of the developing central conduction system and the patterning of coronary vessels may be subject to a level of regulation that is dependent on differential oxygen concentration within cardiac tissues and subsequent HIF‐1 regulation of gene expression. Developmental Dynamics 235:115–123, 2006. © 2005 Wiley‐Liss, Inc.
Regulation ofTwist,Snail, andId1is conserved between the developing murine palate and tooth
Authors: Rice Ritva , Thesleff Irma , Rice David P.C.
Published: July 2005

The development of both the tooth and palate requires coordinated bone morphogenetic protein (BMP) and fibroblast growth factor (FGF) signalling between epithelial and mesenchymal tissues. Here, we demonstrate that transcription factors Twist and Snail are downstream targets of FGF signalling, that Id1 and Msx2 are downstream targets of BMP signalling, and that Msx1 is regulated by both signalling pathways during tooth and palate development. We show thatTwistandSnailexpression in the mesenchyme is regulated by the overlying epithelium and that exogenous FGF4 in tooth and FGF2 in palate can mimic this regulation in isolated mesenchymal explants. Ids act in a dominant‐negative manner to inhibit the function of other transcription factors such as Twist and Snail. FGF and BMP signalling can regulate development antagonistically, and we suggest that FGF‐regulatedTwistandSnailand BMP‐regulatedId1may mediate these antagonistic effects during both tooth and palate development. Developmental Dynamics 234:28–35, 2005. © 2005 Wiley‐Liss, Inc.
nanos is required for formation of the spectrosome, a germ cell‐specific organelle
Authors: Wawersik Matthew , Van Doren Mark
Published: July 2005

Germ cell identity and development are controlled by autonomous cues in the germ plasm as well as by interactions between germ cells and somatic cells. Here, we investigate the formation of a germ cell‐specific organelle, the spectrosome. We find that spectrosome formation is independent of germ cell–soma interactions and is autonomous to the germ cells. Furthermore, the germ plasm component nanos (nos) is essential for spectrosome formation. The role of nos in spectrosome formation is independent of its role in germ cell survival; nos mutant germ cells that are prevented from undergoing programmed cell death still fail to form spectrosomes. Thus, nos is required to regulate the formation of this germ cell‐specific organelle, further supporting a role for nos in promoting germ cell identity. Developmental Dynamics 234:22–27, 2005. © 2005 Wiley‐Liss, Inc.
Equivalence principle for optimization of sparse versus low‐spread representations for signal estimation in noise
Authors: Balan Radu V. , Rosca Justinian , Rickard Scott
Published: July 2005

Estimation of a sparse signal representation, one with the minimum number of nonzero components, is hard. In this paper, we show that for a nontrivial set of the input data the corresponding optimization problem is equivalent to and can be solved by an algorithm devised for a simpler optimization problem. The simpler optimization problem corresponds to estimation of signals under a low‐spread constraint. The goal of the two optimization problems is to minimize the Euclidian norm of the linear approximation error with an lp penalty on the coefficients, for p = 0 (sparse) and p = 1 (low‐spread), respectively. The l0 problem is hard, whereas the l1 problem can be solved efficiently by an iterative algorithm. Here we precisely define the l0 optimization problem, construct an associated l1 optimization problem, and show that for a set with open interior of the input data the optimizers of the two optimization problems have the same support. The associated l1 optimization problem is used to find the support of the l0 optimizer. Once the support of the l0 problem is known, the actual solution is easily found by solving a linear system of equations. However, we point out our approach does not solve the harder optimization problem for all input data and thus may fail to produce the optimal solution in some cases. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 10–17, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20034
Survey of sparse and non‐sparse methods in source separation
Authors: O'Grady Paul D. , Pearlmutter Barak A. , Rickard Scott T.
Published: July 2005

Source separation arises in a variety of signal processing applications, ranging from speech processing to medical image analysis. The separation of a superposition of multiple signals is accomplished by taking into account the structure of the mixing process and by making assumptions about the sources. When the information about the mixing process and sources is limited, the problem is called ‘blind’. By assuming that the sources can be represented sparsely in a given basis, recent research has demonstrated that solutions to previously problematic blind source separation problems can be obtained. In some cases, solutions are possible to problems intractable by previous non‐sparse methods. Indeed, sparse methods provide a powerful approach to the separation of linear mixtures of independent data. This paper surveys the recent arrival of sparse blind source separation methods and the previously existing non‐sparse methods, providing insights and appropriate hooks into theliterature along the way. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15;18–33;2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20035
Variational blind deconvolution of multi‐channel images
Authors: Kaftory Ran , Sochen Nir , Zeevi Yehushua Y.
Published: July 2005

The fundamental problem of denoising and deblurring images is addressed in this study. The great difficulty in this task is due to the ill‐posedness of the problem. We analyze multi‐channel images to gain robustness and regularize the process by the Polyakov action, which provides an anisotropic smoothing term that uses inter‐channel information. Blind deconvolution is then solved by an additional anisotropic regularization term of the same type for the kernel. It is shown that the Beltrami regularizer leads to better results than the total variation (TV) regularizer. An analytic comparison to the TV method is carried out and results on synthetic and real data are demonstrated. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 56–63, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20038
Sparse ICA for blind separation of transmitted and reflected images
Authors: Bronstein Alexander M. , Bronstein Michael M. , Zibulevsky Michael , Zeevi Yehoshua Y.
Published: July 2005

We address the problem of recovering a scene recorded through a semireflecting medium (i.e. planar lens), with a virtual reflected image being superimposed on the image of the scene transmitted through the semirefelecting lens. Recent studies propose imaging through a linear polarizer at several orientations to estimate the reflected and the transmitted components in the scene. In this study we extend the sparse ICA (SPICA) technique and apply it to the problem of separating the image of the scene without having any a priori knowledge about its structure or statistics. Recent novel advances in the SPICA approach are discussed. Simulation and experimental results demonstrate the efficacy of the proposed methods.© 2005 Wiley Periodicals, Inc. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 84–91, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20042
Novel bactericidal surface: Catechin‐loaded surface‐erodible polymer prevents biofilm formation
Authors: Maeyama Ryo , Kwon Il Keun , Mizunoe Yoshimitsu , Anderson James M. , Tanaka Masao , Matsuda Takehisa
Published: July 2005

We developed a novel bactericidal surface based on a catechin‐loaded surface‐erodible polymer. (−)‐Epigallocatechin‐3‐gallate (EGCg), which is the main constituent of tea catechins, showed a dose‐dependent inhibitory effect on Escherichia coli biofilm formation and a dose‐dependent enhanced destructive effect on biofilm. EGCg‐immobilized surfaces were prepared by photopolymerization of liquid biodegradable polyesters. The releasing rate was enhanced with an increase in surface‐erosion rate of photocured polymers. Polymers with high releasing capacity dose‐dependently reduced biofilm formation on the surfaces. The confocal laser scanning microscopic and scanning electron microscopic observations revealed that EGCg induced biofilm‐destructing activities, which include bacterial membrane damage, degradation of exopolysaccharides, and detachment of colonized cells. From these results, potential advantages of the clinical use of catechin‐loaded polymer‐coated implants or catheters are discussed in terms of a reduced occurrence of biomaterial‐centered infections without substantial toxicity or adverse effects. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Biological evaluation of calcium alginate microspheres as a vehicle for the localized delivery of a therapeutic enzyme
Authors: Barrias C. C. , Lamghari M. , Granja P. L. , Sá Miranda M. C. , Barbosa M. A.
Published: July 2005

Gaucher disease (GD) is caused by the decreased activity and/or stability of the lysosomal enzyme glucocerebrosidase (GCR). The available treatment consists in the intravenous administration of exogenous GCR, and is effective in reverting most of the symptoms. However, in terms of bone pathology, which is among the most disabling manifestations, a slow and incomplete response is observed, indicating that adjuvant therapies are necessary to consistently restore GCR activity in bone and accelerate regeneration. In this study, calcium alginate microspheres were analyzed as a vehicle for localized GCR delivery to bone. Results demonstrated that the entrapped enzyme retained full activity and exhibited a broader pH‐dependent activity profile, compared to that of free‐GCR, with improved stability at physiological pH. GCR release profile was established, and it was demonstrated that GCR could be released in a sustained manner. The biological behavior of the system was evaluated by analyzing the uptake of released GCR by GCR‐deficient cells from GD patients, using different techniques: GCR activity measurements, radiolabeling, and cellulose acetate electrophoresis. Results demonstrated that GCR was internalized by cells significantly enhancing the residual enzymatic activity. To achieve an activity reconstitution level comparable to that obtained using free‐GCR, only half of the dose was required with entrapped‐GCR. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Comparison of the effect of surface roughness on the micro/nanotribological behavior of ultra‐high‐molecular‐weight polyethylene (UHMWPE) in air and bovine serum solution
Authors: Check Jason , Karuppiah K. S. Kanaga , Sundararajan Sriram
Published: July 2005

Tribological properties of materials used in biomedical implants critically affect the performance of the implant. A UHMWPE cup paired with a ceramic ball is a popular combination for implants due to its relatively low wear rate. In this study we investigate the effect of surface roughness of UHMWPE on the friction behavior and onset of wear in a UHMWPE/silicon nitride interface in both dry air and bovine serum environments. Microscale multi‐asperity contact is examined using a ball‐on‐flat reciprocating microtribometer. Nanoscale single‐asperity contact and surface topography are examined using atomic force microscopy. Friction was found to increase with a decrease in surface roughness of the UHMWPE sample in air, which is due to an increase in real area of contact. This trend was seen to disappear or even reverse in serum. This is due to an increase in the interfacial shear stress of the UHMWPE surface when exposed to the serum. This increase is believed to be caused by an adhered layer of protein on the UHMWPE surface. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005