bluuebunny/crossref_metadata_2025 huggingface dataset:
Professional Networks in the Life Sciences: Linking the Linked
Authors: Deisboeck Thomas S. , Sagotsky Jonathan
Published: November 2010

The world wide web has furthered the emergence of a multitude of online expert communities. Continued progress on many of the remaining complex scientific questions requires a wide ranging expertise spectrum with access to a variety of distinct data types. Moving beyond peer-to-peer to community-to-community interaction is therefore one of the biggest challenges for global interdisciplinary Life Sciences research, including that of cancer. Cross-domain data query, access, and retrieval will be important innovation areas to enable and facilitate this interaction in the coming years.
Weibull-like Model of Cancer Development in Aging
Authors: Mdzinarishvili Tengiz , Sherman Simon
Published: November 2010

Mathematical modeling of cancer development is aimed at assessing the risk factors leading to cancer. Aging is a common risk factor for all adult cancers. The risk of getting cancer in aging is presented by a hazard function that can be estimated from the observed incidence rates collected in cancer registries. Recent analyses of the SEER database show that the cancer hazard function initially increases with the age, and then it turns over and falls at the end of the lifetime. Such behavior of the hazard function is poorly modeled by the exponential or compound exponential-linear functions mainly utilized for the modeling. In this work, for mathematical modeling of cancer hazards, we proposed to use the Weibull-like function, derived from the Armitage-Doll multistage concept of carcinogenesis and an assumption that number of clones at age t developed from mutated cells follows the Poisson distribution. This function is characterized by three parameters, two of which ( r and λ) are the conventional parameters of the Weibull probability distribution function, and an additional parameter ( C0) that adjusts the model to the observational data. Biological meanings of these parameters are: r—the number of stages in carcinogenesis, λ—an average number of clones developed from the mutated cells during the first year of carcinogenesis, and C0—a data adjustment parameter that characterizes a fraction of the age-specific population that will get this cancer in their lifetime. To test the validity of the proposed model, the nonlinear regression analysis was performed for the lung cancer (LC) data, collected in the SEER 9 database for white men and women during 1975–2004. Obtained results suggest that: (i) modeling can be improved by the use of another parameter A- the age at the beginning of carcinogenesis; and (ii) in white men and women, the processes of LC carcinogenesis vary by A and C0, while the corresponding values of r and λ are nearly the same. Overall, the proposed Weibull-like model provides an excellent fit of the estimates of the LC hazard function in aging. It is expected that the Weibull-like model can be applicable to fit estimates of hazard functions of other adult cancers as well.
LTR: Linear Cross-Platform Integration of Microarray Data
Authors: Boutros Paul C.
Published: November 2010

The size and scope of microarray experiments continue to increase. However, datasets generated on different platforms or at different centres contain biases. Improved techniques are needed to remove platform- and batch-specific biases. One experimental control is the replicate hybridization of a subset of samples at each site or on each platform to learn the relationship between the two platforms. To date, no algorithm exists to specifically use this type of control. LTR is a linear-modelling-based algorithm that learns the relationship between different microarray batches from replicate hybridizations. LTR was tested on a new benchmark dataset of 20 samples hybridized to different Affymetrix microarray platforms. Before LTR, the two platforms were significantly different; application of LTR removed this bias. LTR was tested with six separate data pre-processing algorithms, and its effectiveness was independent of the pre-processing algorithm. Sample-size experiments indicate that just three replicate hybridizations can significantly reduce bias. An R library implementing LTR is available.
Comparative Molecular Evolution of Trichoderma Chitinases in Response to Mycoparasitic Interactions
Authors: Ihrmark Katarina , Asmail Nashwan , Ubhayasekera Wimal , Melin Petter , Stenlid Jan , Karlsson Magnus
Published: November 2010

Certain species of the fungal genus Trichoderma are potent mycoparasites and are used for biological control of fungal diseases on agricultural crops. In Trichoderma, whole-genome sequencing reveal between 20 and 36 different genes encoding chitinases, hydrolytic enzymes that are involved in the mycoparasitic attack. Sequences of Trichoderma chitinase genes chi18-5, chi18-13, chi18-15 and chi18-17, which all exhibit specific expression during mycoparasitism-related conditions, were determined from up to 13 different taxa and studied with regard to their evolutionary patterns. Two of them, chi18-13 and chi18-17, are members of the B1/B2 chitinase subgroup that have expanded significantly in paralog number in mycoparasitic Hypocrea atroviridis and H. virens. Chi18-13 contains two codons that evolve under positive selection and seven groups of co-evolving sites. Chi18-15 displays a unique codon-usage and contains five codons that evolve under positive selection and three groups of co-evolving sites. Regions of high amino acid variability are preferentially localized to substrate- or product side of the catalytic clefts. Differences in amino acid diversity/conservation patterns between different Trichoderma clades are observed. These observations show that Trichoderma chitinases chi18-13 and chi18-15 evolve in a manner consistent with rapid co-evolutionary interactions and identifies putative target regions involved in determining substrate-specificity.
An Application of Supertree Methods to Mammalian Mitogenomic Sequences
Authors: Campbell Véronique , Lapointe François-Joseph
Published: November 2010

Two different approaches can be used in phylogenomics: combined or separate analysis. In the first approach, different datasets are combined in a concatenated supermatrix. In the second, datasets are analyzed separately and the phylogenetic trees are then combined in a supertree. The supertree method is an interesting alternative to avoid missing data, since datasets that are analyzed separately do not need to represent identical taxa. However, the supertree approach and the corresponding consensus methods have been highly criticized for not providing valid phylogenetic hypotheses. In this study, congruence of trees estimated by consensus and supertree approaches were compared to model trees obtained from a combined analysis of complete mitochondrial sequences of 102 species representing 93 mammal families. The consensus methods produced poorly resolved consensus trees and did not perform well, except for the majority rule consensus with compatible groupings. The weighted supertree and matrix representation with parsimony methods performed equally well and were highly congruent with the model trees. The most similar supertree method was the least congruent with the model trees. We conclude that some of the methods tested are worth considering in a phylogenomic context.
Assessment of the Quality of Water from Hand-Dug Wells in Ghana
Authors: Nkansah Marian Asantewah , Boadi Nathaniel Owusu , Badu Mercy
Published: November 2010

This study focused upon the determination of physicochemical and microbial properties, including metals, selected anions and coliform bacteria in drinking water samples from hand-dug wells in the Kumasi metropolis of the Republic of Ghana. The purpose was to assess the quality of water from these sources. Ten different water samples were taken from different parts of Kumasi, the capital of the Ashanti region of Ghana and analyzed for physicochemical parameters including pH, electrical conductivity, total dissolved solids, alkalinity total hardness and coliform bacteria. Metals and anions analyzed were Ca, Mg, Fe, Mn, NO3–, NO2–, SO42-, PO42-, F– and Cl–. Bacteria analysed were total coliform and Escherichia coli.

The data showed variation of the investigated parameters in samples as follows: pH, 6.30-0.70; conductivity (EC), 46-682 μS/cm; PO43-, 0.67-76.00 mg/L; F–, 0.20-0.80 mg/L; NO3–, 0-0.968 mg/L; NO2–, 0-0.063 mg/L; SO42-, 3.0-07.0 mg/L; Fe, 0-1.2 mg/L; Mn, 0-0.018 mg/L. Total coliform and Escherichia coli were below the minimum detection limit (MDL) of 20 MPN per 100 ml in all the samples. The concentrations of most of the investigated parameters in the drinking water samples from Ashanti region were within the permissible limits of the World Health Organization drinking water quality guidelines.
A Picture of the Healthful Food Environment in Two Diverse Urban Cities
Authors: Lee Rebecca E. , Heinrich Katie M. , Medina Ashley V. , Regan Gail R. , Reese-Smith Jacqueline Y. , Jokura Yuka , Maddock Jay E.
Published: November 2010

Background

Local food environments influence fresh produce purchase and consumption, and previous research has found disparities in local food environments by income and ethnicity. Other existing studies have begun to quantify the distribution of food sources, but there has been limited attention to important features or types of healthful food that are available or their quality or cost. Two studies assessed the type, quantity, quality and cost of healthful food from two diverse urban cities, Kansas City, Kansas and Missouri and Honolulu, Hawaii, and evaluated differences by neighborhood income and ethnic composition.

Method

A total of 343 food stores in urban neighborhoods were assessed using the one-page Understanding Neighborhood Determinants of Obesity (UNDO) Food Stores Assessment (FSA) measuring healthful foods. US Census data were used to define median household income and ethnic minority concentration.

Results

In Study 1, most low socioeconomic status (SES), high ethnic minority neighborhoods had primarily convenience, liquor or small grocery stores. Quality of produce was typically lower, and prices of some foods were more than in comparison neighborhoods. In Study 2, low SES neighborhoods had more convenience and grocery stores. Farmers’ markets and supermarkets had the best produce availability and quality, and farmers’ markets and pharmacies had the lowest prices.

Conclusions

Messages emphasizing eating more fruits and vegetables are not realistic in urban, low SES, high ethnic concentration neighborhoods. Farmers’ markets and supermarkets provided the best opportunities for fresh produce. Increasing access to farmers’ markets and supermarkets or reducing prices could improve the local food environment.
Antiplasmodial Activity of Some Medicinal Plants Used in Sudanese Folk-medicine
Authors: Ahmed El-Hadi M. , Nour Bakri Y.M. , Mohammed Yousif G. , Khalid Hassan s.
Published: November 2010

Ten plants indigenous to Sudan and of common use in Sudanese folk-medicine, were examined in vitro for antimalarial activity against schizonts maturation of Plasmodium falciparum, the major human malaria parasite. All plant samples displayed various antiplasmodial activity. Three plant extracts caused 100% inhibition of the parasite growth at concentrations of plant material ≤ 500 ug/ml. The two most active extracts that produced 100% inhibition of the parasite growth at concentration of plant material ≥ 50 μg/ml were obtained from the seeds of Nigella sativa and the whole plant of Aristolochia bracteolata. The ten plants were phytochemically screened for their active constituents. The two most active plants showed the presence of sterols, alkaloids and tannins.
A Brief Review of Silicosis in the United States
Authors: Thomas Carson R. , Kelley Timothy R.
Published: November 2010

Silicosis may be defined as the disease resulting from chronic occupational exposure to silica dust. Silica is primarily composed of quartz dust and has been classified since 2000 as a known human carcinogen by the U.S. government. Silicosis may lead to impairment of lung function resulting from fibrosis of the lungs. This may in turn lead to an increased susceptibility to the development of tuberculosis. Respirable particles are in the size range of less than one micrometer to as large as 30 micrometers. Silicosis is an untreatable, but preventable disease. This review explores the history of silicosis in the U.S. mining industry, including case studies of occupational silicosis.
Effect of a Manager Training and Certification Program on Food Safety and Hygiene in Food Service Operations
Authors: Kassa Hailu , Silverman Gary S. , Baroudi Karim
Published: November 2010

Food safety is an important public health issue in the U.S. Eating at restaurants and other food service facilities increasingly has been associated with food borne disease outbreaks. Food safety training and certification of food mangers has been used as a method for reducing food safety violations at food service facilities. However, the literature is inconclusive about the effectiveness of such training programs for improving food safety and protecting consumer health. The purpose of this study was to examine the effect of food manger training on reducing food safety violations. We examined food inspection reports from the Toledo/Lucas County Health Department (Ohio) from March 2005 through February 2006 and compared food hygiene violations between food service facilities with certified and without certified food managers. We also examined the impact on food safety of a food service facility being part of a larger group of facilities.

Restaurants with trained and certified food managers had significantly fewer critical food safety violations but more non-critical violations than restaurants without certified personnel. Institutional food service facilities had significantly fewer violations than restaurants, and the number of violations did not differ as a function of certification. Similarly, restaurants with many outlets had significantly fewer violations than restaurants with fewer outlets, and training was not associated with lower numbers of violations from restaurants with many outlets. The value of having certified personnel was only observed in independent restaurants and those with few branches. This information may be useful in indicating where food safety problems are most likely to occur. Furthermore, we recommend that those characteristics of institutional and chain restaurants that result in fewer violations should be identified in future research, and efforts made to apply this knowledge at the level of individual restaurants.
QSPR Modeling of Bioconcentration Factors of Nonionic Organic Compounds
Authors: Deeb Omar , Khadikar Padmakar V. , Goodarzi Mohammad
Published: November 2010

The terms bioaccumulation and bioconcentration refer to the uptake and build-up of chemicals that can occur in living organisms. Experimental measurement of bioconcentration is time-consuming and expensive, and is not feasible for a large number of chemicals of potential regulatory concern. A highly effective tool depending on a quantitative structure-property relationship (QSPR) can be utilized to describe the tendency of chemical concentration organisms represented by, the important ecotoxicological parameter, the logarithm of Bio Concentration Factor (log BCF) with molecular descriptors for a large set of non-ionic organic compounds. QSPR models were developed using multiple linear regression, partial least squares and neural networks analyses. Linear and non-linear QSPR models to predict log BCF of the compounds developed for the relevant descriptors. The results obtained offer good regression models having good prediction ability. The descriptors used in these models depend on the volume, connectivity, molar refractivity, surface tension and the presence of atoms accepting H-bonds.
The Effect of the Gravitation of the Moon on Frequency of Births
Authors: Wake Ryotaro , Misugi Takuya , Shimada Kenei , Yoshiyama Minoru
Published: November 2010

The purpose of this study was to examine the influence of the gravitation of the Moon on the frequency of births in Kyoto, Japan. A retrospective cohort analysis of 1007 consecutive births without the use of the induction agents was conducted on a population of births in a private midwife hospital from January, 1966 to December, 2000. There was a significant increase in the cases of births, when the gravitation of the Moon to the Earth was less than 31.5 N. Results of this study suggest that the gravitation of the Moon has an influence on the frequency of births.
Air Pollution and Emergency Department Visits for Suicide Attempts in Vancouver, Canada
Authors: Szyszkowicz Mieczystaw , Willey Jeff B. , Grafstein Eric , Rowe Brian H. , Colman Ian
Published: November 2010

Background

Comorbidity of depression, heart disease, and migraine has been observed in clinical practice, while ambient air pollution has been identified among different risk factors for these health conditions. Suicide attempts and ideations as the result of depression may be linked to air pollution exposure. Therefore the effects of ambient air pollution on emergency department (ED) visits for suicide attempts were investigated.

Methods

Emergency visit data were collected in a hospital in Vancouver, Canada. The generalized linear mixed models technique was applied in the analysis of these data. A natural hierarchical structure of the data was used to define the clusters, with days nested in a 3-level structure (day of week, month, year). Poisson models were fitted to the clustered counts of ED visits with a single air pollutant, temperature and relative humidity. In addition, the case-crossover methodology was used with the same data for comparison. The analysis was performed by gender (all, males, females) and month (all: January-December, warm: April-September, cold: October-March).

Results

Both hierarchical and case-crossover methods confirmed positive and statistically significant associations among carbon monoxide (CO), nitrogen dioxide (NO2), sulphur dioxide (SO2), and particulate matter (PM10) for all suicide attempts in the cold period. The largest increase was observed for males in the cold period for a 1-day lagged exposure to NO2, with an excess risk of 23.9% (95% CI: 7.8, 42.4) and odds ratio of 1.21 (95% CI: 1.03, 1.41). In warm months the associations were not statistically significant, and the highest positive value was obtained for ozone lagged by 1 day.

Conclusion

The results indicate a potential association between air pollution and emergency department visits for suicide attempts.
Seasonal and spatial variability of surface ozone over China: contributions from background and domestic pollution
Authors: Wang Y. , Zhang Y. , Hao J. , Luo M.
Published: November 2010

Abstract. Both observations and a 3-D chemical transport model suggest that surface ozone over populated eastern China features a significant drop in mid-summer and that the peak month differs by latitude and region. Source-receptor analysis is used to quantify the contributions of background ozone and Chinese anthropogenic emissions on this variability. Annual mean background ozone over China shows a spatial gradient from 55 ppbv in the northwest to 20 ppbv in the southeast, corresponding with changes in topography and ozone lifetime. Anthropogenic background (annual mean of 12.6 ppbv) shows distinct troughs in the summer and peaks in the spring. On the monthly-mean basis, Chinese pollution ozone (CPO) has a peak of 20–25 ppbv in June north of the Yangtze River and in October south of it, which explains the peaks of surface ozone in these months. The mid-summer drop in ozone over eastern China is driven by the decrease of background ozone (−15 ppbv). Tagged simulations suggest that this decrease is driven by reduced transport from Europe and North America, whereas ozone from Southeast Asia and Pacific Ocean exhibits a maximum in the summer over eastern China. This contrast in seasonality provides clear evidence that the seasonal switch in monsoonal wind patterns plays a significant role in determining the seasonality of background ozone over China.
Secondary aerosol formation from photochemical aging of aircraft exhaust in a smog chamber
Authors: Miracolo M. A. , Hennigan C. J. , Ranjan M. , Nguyen N. T. , Gordon T. D. , Lipsky E. M. , Presto A. A. , Donahue N. M. , Robinson A. L.
Published: November 2010

Abstract. Field experiments were performed to investigate the effects of photo-oxidation on fine particle emissions from an in-use CFM56-2B gas turbine engine mounted on a KC-135 Stratotanker airframe. Emissions were sampled into a portable smog chamber from a rake inlet installed one-meter downstream of the engine exit plane of a parked and chocked aircraft. The chamber was then exposed to sunlight and/or UV lights to initiate photo-oxidation. Separate tests were performed at different engine loads (4, 7, 30, 85%). Photo-oxidation created substantial secondary particulate matter (PM), greatly exceeding the direct PM emissions at each engine load after an hour or less of aging at typical summertime conditions. After several hours of photo-oxidation, the ratio of secondary-to-primary PM mass was on average 35 ± 4.1, 17 ± 2.5, 60 ± 2.2, and 2.7 ± 1.1 times the primary PM for the 4, 7, 30, and 85% load experiments, respectively. The composition of secondary PM formed strongly depended on load. At 4% load, secondary PM was dominated by secondary organic aerosol (SOA). At higher loads, the secondary PM was mainly secondary sulfate. Predictions of an SOA model are compared to the measured SOA formation. The SOA model predicts ~40% of the SOA produced during the 4% load experiment and ~60% for the 85% load experiment. Significant emissions of low-volatility compounds present in both the vapor- and particle-phase were measured in the exhaust and represent a significant pool of SOA precursors that appear to form SOA efficiently when oxidized. These results underscore the importance of accounting for atmospheric processing when assessing the influence of aircraft emissions on ambient PM levels.
Sources and production of organic aerosol in Mexico City: insights from the combination of a chemical transport model (PMCAMx-2008) and measurements during MILAGRO
Authors: Tsimpidi A. P. , Karydis V. A. , Zavala M. , Lei W. , Bei N. , Molina L. , Pandis S. N.
Published: November 2010

Abstract. Urban areas are large sources of organic aerosols and their precursors. Nevertheless, the contributions of primary (POA) and secondary organic aerosol (SOA) to the observed particulate matter levels have been difficult to quantify. In this study the three-dimensional chemical transport model PMCAMx-2008 is used to investigate the temporal and geographic variability of organic aerosol in the Mexico City Metropolitan Area (MCMA) during the MILAGRO campaign that took place in the spring of 2006. The organic module of PMCAMx-2008 is based on the volatility basis-set approach: both primary and secondary organic components are assumed to be semi-volatile and photochemically reactive and are distributed in logarithmically spaced volatility bins. The MCMA emission inventory is modified and the POA emissions are distributed by volatility based on dilution experiments. The model predictions are compared with observations from four different types of sites, an urban (T0), a suburban (T1), a rural (T2), and an elevated site in Pico Tres Padres (PTP). The performance of the model in reproducing organic mass concentrations in these sites was encouraging. The average predicted PM1 OA concentration in T0, T1, and T2 was 18 μg m−3, 11.7 μg m−3, and 10.5 μg m−3 respectively, while the corresponding measured values were 17.2 μg m−3, 11 μg m−3, and 9 μg m−3. The average predicted fresh primary OA concentrations were 4.4 μg m−3 at T0, 1.2 μg m−3 at T1 and 1.7 μg m−3 at PTP in reasonably good agreement with the corresponding PMF analysis estimates based on the AMS observations of 4.5, 1.3, and 2.9 μg m−3 respectively. The model reproduced reasonably well the average oxygenated OA (OOA) levels in T0 (7.5 μg m−3 predicted versus 7.5 μg m−3 measured), in T1 (6.3 μg m−3 predicted versus 4.6 μg m−3 measured) and in PTP (6.6 μg m−3 predicted versus 5.9 μg m−3 measured). Inside Mexico City, the locally produced OA is predicted to be on average 53% fresh primary (POA), 11% semi-volatile (S-SOA) and intermediate volatile (I-SOA) organic aerosol, and 36% traditional SOA from the oxidation of VOCs (V-SOA). The long range transport from biomass burning activities and other sources in Mexico is predicted to contribute on average almost as much as the local sources during the MILAGRO period.
Soil organic matter dynamics in a North America tallgrass prairie after 9 years of experimental warming
Authors: Cheng X. , Luo Y. , Xu X. , Zhang Q.
Published: November 2010

Abstract. The influence of global warming on soil organic matter (SOM) in terrestrial ecosystems remains unclear. In this study, we combined soil fractionation with isotope analyses to examine SOM dynamics after nine years of experimental warming in a North America tallgrass prairie. Soil samples from the control plots and the warmed plots were separated in four aggregate sizes (>2000 μm, 250–2000 μm, 53–250 μm and <53 μm), and three density fractions (free light fraction (LF), intra aggregate particulate organic matter (iPOM) and mineral-associated organic matter (mSOM)). All fractions were analyzed for their C and N contents, and δ13C and δ15N values. Warming did not significantly affect soil aggregate distributions and stability but increased C4-derived C input into all fractions with the greatest one in LF. Warming also stimulated decay rates of C in whole soil and all aggregate sizes. C in the LF turned over faster than that in iPOM in the warmed soils. The δ15N values of soil fractions were more enriched in the warmed soils than those in the control, indicating that warming accelerated loss of soil N. The δ15N values changed from low to high while C:N ratios from high to low in order of LF, iPOM, and mSOM due to increased degree of decomposition and mineral association. Overall, warming increased the input of C4-derived C by 11.6%, which was negated by the accelerated loss of soil C. Our results suggest that global warming simultaneously stimulated C input via shift in species composition and decomposition of SOM, resulting in negligible net change in soil C.
Melting trends over the Greenland ice sheet (1958-2009) from spaceborne microwave data and regional climate models
Authors: Fettweis X. , Tedesco M. , van den Broeke M. , Ettema J.
Published: November 2010

Abstract. To study near-surface melt changes over the Greenland ice sheet (GrIS) since 1979, melt extent estimates from two regional climate models are compared with those obtained from spaceborne microwave brightness temperatures using two different remote sensing algorithms. Results from the two models are consistent with those obtained with the remote sensing algorithms, at both daily and yearly time scales, encouraging the use of the models for analyzing melting trends before the satellite era (1958–1979), when forcing data is available. Differences between satellite-derived and model-simulated results still occur and are here used to identify (i) biases in the snow models (notably in the albedo parametrization, in the thickness of a snow layer, in the maximum liquid water content within the snowpack and in the snowfall impacting the bare ice appearance in summer) and (ii) limitations in the use of passive microwave data for snowmelt detection at the edge of the ice sheet due to mixed pixel effect (e.g., tundra or rock nearby the ice sheet). Results from models and spaceborne microwave sensors confirm a significant (p-value = 0.01) increase in GrIS surface melting since 1979. Melt extent recorded over the last years (1998, 2003, 2005 and 2007) is unprecedented in the last 50 years with the cumulated melt area in the 2000's being, on the average, twice as that occurring during the 1980's.
A Novel Training‐Free Cast FeMnSiCrNi Shape Memory Alloy Based on Formation of Martensite in a Domain‐Specific Manner
Authors: Wen Yuhua , Peng Huabei , Wang Chaoping , Yu Qinxu , Li Ning
Published: November 2010

The proposed key to producing a good shape memory effect in FeMnSi alloys is to reduce or even prevent the collisions between martensite bands. A method for realizing this is to make stress‐induced martensite bands form in a domain‐specific manner. We developed a novel training‐free cast Fe18Mn5.5Si9.5Cr4Ni alloy with residual lathy delta ferrite based on this idea. The recovery strain reached 6.4% only after annealing the cast Fe18Mn5.5Si9.5Cr4Ni alloy. Microstructure observations indicated that the lathy delta ferrite made the stress‐induced martensite form in a domain‐specific manner by first subdividing grains into smaller domains. We hypothesize that through adjusting alloy compositions, solidification parameters, and heat treatment technique, the shape recovery of cast FeMnSi alloys can be further improved. Such a finding will provide a novel method for developing training‐free FeMnSi shape memory alloys.
Melt Electrospinning
Authors: Hutmacher Dietmar W. , Dalton Paul D.
Published: November 2010

Melt electrospinning is relatively under‐investigated compared to solution electrospinning but provides opportunities in numerous areas, in which solvent accumulation or toxicity are a concern. These applications are diverse, and provide a broad set of challenges to researchers involved in electrospinning. In this context, melt electrospinning provides an alternative approach that bypasses some challenges to solution electronspinning, while bringing new issues to the forefront, such as the thermal stability of polymers. This Focus Review describes the literature on melt electrospinning, as well as highlighting areas where both melt and solution are combined, and potentially merge together in the future.
Irreversible effects of retinoic acid pulse onXenopusjaw morphogenesis: new insight into cranial neural crest specificationb
Authors: Vieux‐Rochas Maxence , Bouhali Kamal , Baudry Sabrina , Fontaine Anastasia , Coen Laurent , Levi Giovanni
Published: November 2010

Jaws are formed by cephalic neural crest (CNCCs) and mesodermal cells migrating to the first pharyngeal arch (PA1). A complex signaling network involving different PA1 components then establishes the jaw morphogenetic program. To gather insight on this developmental process, in this study, we analyze the teratogenic effects of brief (1–15 min) pulses of low doses of retinoic acid (RA: 0.25–2 µM) or RA agonists administered to earlyXenopus laevis(X.l.) embryos. We show that these brief pulses of RA cause permanent craniofacial defects specifically when treatments are performed during a 6‐hr window (developmental stages NF15–NF23) that covers the period of CNCCs maintenance, migration, and specification. Earlier or later treatments have no effect. Similar treatments performed at slightly different developmental stages within this temporal window give rise to different spectra of malformations. The RA‐dependent teratogenic effects observed inXenopuscan be partially rescued by folinic acid. We provide evidence suggesting that inXenopus, as in the mouse, RA causes craniofacial malformations by perturbing signaling to CNCCs. Differently from the mouse, where RA affects CNCCs only at the end of their migration, inXenopus,RA has an effect on CNCCs during all the period ranging from their exit from the neural tube until their arrival in the PA1. Our findings provide a conceptual framework to understand the origin of individual facial features and the evolution of different craniofacial morphotypes.Birth Defects Res (Part B)89:493–503, 2010. © 2010 Wiley‐Liss, Inc.
Tissue engineering for clinical applications
Authors: Bhatia Sujata K.
Published: November 2010

Tissue engineering is increasingly being recognized as a beneficial means for lessening the global disease burden. One strategy of tissue engineering is to replace lost tissues or organs with polymeric scaffolds that contain specialized populations of living cells, with the goal of regenerating tissues to restore normal function. Typical constructs for tissue engineering employ biocompatible and degradable polymers, along with organ‐specific and tissue‐specific cells. Once implanted, the construct guides the growth and development of new tissues; the polymer scaffold degrades away to be replaced by healthy functioning tissue. The ideal biomaterial for tissue engineering not only defends against disease and supports weakened tissues or organs, it also provides the elements required for healing and repair, stimulates the body's intrinsic immunological and regenerative capacities, and seamlessly interacts with the living body. Tissue engineering has been investigated for virtually every organ system in the human body. This review describes the potential of tissue engineering to alleviate disease, as well as the latest advances in tissue regeneration. The discussion focuses on three specific clinical applications of tissue engineering: cardiac tissue regeneration for treatment of heart failure; nerve regeneration for treatment of stroke; and lung regeneration for treatment of chronic obstructive pulmonary disease.
Chitin deacetylase product inhibition
Authors: Jaworska Malgorzata M.
Published: November 2010

Chitin deacetylase is the only known enzyme catalyzing the hydrolysis of the acetamino linkage in the N‐acetylglucosamine units of chitin and chitosan. This reaction can play an important role in enzymatic production of chitosan from chitin, or in enzymatic modification of chitosan, which has applications in medicine, pharmacy or plant protection. It was previously shown that acetic acid, a product of the deacetylation process, may act as an inhibitor of chitin deacetylase. Here we show the mechanism of inhibition of chitin deacetylase isolated from Absidia orchidis vel coerulea by acetic acid released during the deacetylation process. The process follows competitive inhibition with respect to acetic acid with an inhibition constant of Ki = 0.286 mmol/L. These results will help to find the optimal system to carry out the enzymatic deacetylation process for industrial applications.
Financial research in Canada: A long‐term assessment of journal publications
Authors: Chan Kam C. , Chang Chih‐Hsiang , Chen Yining
Published: November 2010

We examined the financial research among Canadian academic institutions between 1990–2008. Overall, Canadian institutions contribute 3.79% of all publications in 23 leading finance journals. The five most productive universities are the University of British Columbia, the University of Toronto, Wilfrid Laurier University, McGill University, and the University of Alberta. The research productivity of Canadian universities is comparable to their counterparts in Australia and the UK. However, when examining only the top four finance journals, Canadian universities clearly outperform their counterparts in Australia and the UK. In addition, we find that the sufficiency of research funding, the size of faculty, as well as the assembly of a cohort of research‐active faculty contribute to the research productivity of finance programs in Canada. Copyright © 2010 ASAC. Published by John Wiley & Sons, Ltd.
Artificial [FeFe]‐Hydrogenase: On Resin Modification of an Amino Acid to Anchor a Hexacarbonyldiiron Cluster in a Peptide Framework
Authors: Roy Souvik , Shinde Sandip , Hamilton G. Alexander , Hartnett Hilairy E. , Jones Anne K.
Published: November 2010

A general method for immobilization of synthetic analogues of the [FeFe]‐hydrogenase in designed peptides via on resin modification of an amino acid side chain with a dithiol functional group is described. Utilizing a unique amine side chain as anchor, the dithiol unit is coupled to the peptide via formation of an amide. This dithiol unit precisely positions the two required sulfur atoms for the formation of a [(μ‐SRS){Fe(CO)3}2] cluster on reaction with [Fe3(CO)12]. UV/Vis and FTIR spectroscopy demonstrate formation of the desired complex.
Synthesis and Preferred Conformations of All Regio‐ and Diastereoisomeric Methyl 2,3‐Fluorohydroxyalkanoates
Authors: Husstedt Wibke S. , Wiehle Susanne , Stillig Christian , Bergander Klaus , Grimme Stefan , Haufe Günter
Published: November 2010

Selective syntheses of enantiopure regio‐ and diastereomeric methyl 2,3‐fluoro‐hydroxyalkanoates via four different routes employing two types of fluorination reagents are reported. The anti‐ and syn‐3‐fluoro‐2‐hydroxyalkanoates 1 and 3 were prepared by treating the corresponding epoxides with Olah's reagent (Py·9HF). Cyclic sulfates prepared from the enantiomeric diols were ring‐opened with TBAF to give the anti‐ and syn‐2‐fluoro‐3‐hydroxyalkanoates 2 and 4. Thestereochemical analysis was performed mainly by NMR spectroscopy. Applying DFT/B3LYP and SCS‐MP2 quantum chemical methods, the coupling constants and relative energies of conformers were calculated. Solvent effects were considered using the COSMO continuum model.
Direct Electroanalysis of p‐Nitrophenol (PNP) in Estuarine and Surface Waters by a High Sensitive Type C/p‐NiTSPc Coating Carbon Fiber Microelectrode (CFME)
Authors: Pontié M. , Sikpo L. , Thouand G. , Lahan R. , Tapsoba I. , Mallet R. , Feng T.
Published: November 2010

We report for the first time on the elaboration of a remarkable sensitivity type C/p‐NiTSPc carbon fiber microelectrode (CFME) for p‐nitrophenol (PNP) pollutant. We observed the best performances using square wave voltammetry (SWV) technique in the place of differential pulse voltammetry (DPV). Also the combination of p‐NiTSPc optimized cycles of electrodeposition and accumulation time, helped us to increase remarkably the sensor slope (320 times) and the limit of detection (LOD) (1000 times), with a final LOD of 0.1 µg/L, the current regulatory limit for drinkable waters. Furthermore the recoveries of the standards added are close to 100 % indicating that the method has some suitability. The proposed voltammetric procedure might be applied for organophosphorus pesticides and their by‐products with a remarkable sensing in natural polluted waters.
A shift approach for the dynamic response of rigid‐plastic systems
Authors: Voyagaki Elia , Mylonakis George , Psycharis Ioannis N.
Published: November 2010

A shift approach is presented for evaluating and interpreting the response of rigid‐perfectly plastic single‐degree‐of‐freedom systems to dynamic loading. Scaling laws for such systems are, as the term suggests, multiplicative in nature, relating peak dynamic response to products of key problem parameters such as linear spectral coordinates, force reduction coefficient and peak values of the excitation and its time derivatives. Contrary to classical laws, the proposed approach is additive, imposing a shift in the ordinates and the abscissa of the excitation function by means of a set of parameters uniquely related to the yielding resistance of the system. The dynamic response is then obtained by integrating the modified excitation function in a linear‐like manner within a particular yielding branch, for the nonlinearity is incorporated into the forcing term. The mathematical validity of the approach is demonstrated analytically and its importance is highlighted for systems with symmetric yielding resistance subjected to near‐fault earthquake motions. The modified excitation function may be discontinuous between different yielding branches and relates uniquely to the development of plastic deformation. It is thereby referred to as Plastic Input Motion (PIM). It is shown that the ordinates and the duration of this function may be significantly (yet not necessarily) smaller than those of the original ground motion depending on yield strength. The relationship of the proposed approach to the existing methods and parameters of earthquake engineering such as Newmark's sliding block and relative ground acceleration, is discussed. Copyright © 2010 John Wiley & Sons, Ltd.
Increased adult hippocampal neurogenesis and abnormal migration of adult‐born granule neurons is associated with hippocampal‐specific cognitive deficits in phospholipase C‐β1 knockout mice
Authors: Manning Elizabeth E. , Ransome Mark I. , Burrows Emma L. , Hannan Anthony J.
Published: November 2010

Schizophrenia is a devastating psychiatric illness with a complex pathophysiology. We have recently documented schizophrenia‐like endophenotypes in phospholipase C‐β1 knockout (PLC‐β1−/−) mice, including deficits in prepulse inhibition, hyperlocomotion, and cognitive impairments. PLC‐β1 signals via multiple G‐protein coupled receptor pathways implicated in neural cellular plasticity; however, adult neurogenesis has yet to be explored in this knockout model. In this study, weemployed PLC‐β1−/−mice to elucidate possible correlates between aberrant adult hippocampal neurogenesis (AHN) and schizophrenia‐like behaviors. Using stereology and bromodeoxyuridine (BrdU) immunohistochemistry we demonstrated a significant increase in the density of adult‐generated cells in the granule cell layer (GCL) of adult PLC‐β1−/−mice compared with wild‐type littermates. Cellular phenotype analysis using confocal microscopy revealed these cells to be mature granule neurons expressing NeuN and calbindin. Increased neuronal survival occurred concomitant with reduced caspase‐3(+) cells in the GCL of PLC‐β1−/−mice. Stereological analysis of Ki67(+) cells in the subgranular zone suggested that neural precursor proliferation is unchanged in PLC‐β1−/−mice. We further showed aberrant migration of mature granule neurons within the GCL of adult PLC‐β1−/−mice with excessive adult‐generated mature neurons residing in the middle and outer GCL. PLC‐β1−/−mice exhibited specific behavioral deficits in location recognition, a measure of hippocampal‐dependent memory, but not novel object recognition. Overall, we have shown that PLC‐β1−/−mice have a threefold increase in net AHN, and have provided further evidence to suggest a specific deficit in hippocampal‐dependent cognition. We propose that abnormal cellular plasticity in these mice may contribute to their schizophrenia‐like behavioral endophenotypes. © 2010 Wiley Periodicals, Inc.
Multiple uses of basement membrane‐like matrix (BME/Matrigel) in vitro and in vivo with cancer cells
Authors: Benton Gabriel , Kleinman Hynda K. , George Jay , Arnaoutova Irina
Published: November 2010

Significant advances in our understanding of cancer cell behavior, growth, and metastasis have been facilitated by studies using a basement membrane‐like extracellular matrix extract, also known as Matrigel. The basement membrane is a thin extracellular matrix that is found in normal tissues and contacts epithelial and endothelial cells, smooth muscle, fat, Schwann cells, etc. It is composed of mainly laminin‐111, collagen IV, heparan sulfate proteoglycan, entactin/nidogen, and various growth factors (fibroblast growth factor, transforming growth factor beta, epidermal growth factor, etc.). Most tumors of epithelial origin produce significant amounts of basement membrane matrix and interact with it particularly during metastasis. Cancer cells metastasize via degradation of the vessel basement membrane matrix to extravasate into the blood stream and colonize distant sites. This review will focus on the interaction of cancer cells and cancer stem cells with the basement membrane‐like matrix and the various uses of this interaction to accelerate tumor growth in vivo and to develop in vitro assays for invasion, morphology, and dormancy. Such assays and methods have advanced our understanding of the process of cancer progression, the genes and pathways that are involved, the potential of various therapeutic agents, the effects of neighboring cells, and the role of stem cells.
Functional role of inositol‐1,4,5‐trisphosphate‐3‐kinase‐A for motility of malignant transformed cells
Authors: Windhorst Sabine , Kalinina Tatyana , Schmid Katharina , Blechner Christine , Kriebitzsch Neele , Hinsch Robin , Chang Lydia , Herich Lena , Schumacher Udo , Mayr Georg W.
Published: November 2010

Cell migration is one of the hallmarks of metastatic disease and thus identification of migration promoting proteins is crucial for the understanding of metastasis formation. Here we show that the neuron‐specific, F‐actin bundling inositol‐1,4,5‐trisphosphate‐3‐kinase‐A (ITPKA) is ectopically expressed in tumor cells and critically involved in migration. Down‐regulation of ITPKA expression in transformed cell‐lines with ectopic expression of ITPKA significantly decreased migration and the number of linear and branched cell protrusion. Conversely, up‐regulation of ITPKA in tumor cell lines with low endogenous ITPKA expression increased migration and formation of cell processes. In vitro, ITPKA alone induced the formation of linear actin filaments, whereas ITPKA mediated formation of branched protrusions seems to result from interaction between ITPKA and the F‐actin cross‐linking protein filamin C. Based on these actin‐modulating and migration‐promoting effects of ITPKA we examined its expression in clinical samples of different tumor entities, starting with the analysis of multiple tumor tissue arrays. As in lung adenocarcinoma specimens, the highest ITPKA expression rate was found, this tumor entity was examined in more detail. ITPKA was expressed early in adenocarcinoma progression (pN0) and was largely maintained in invasive and metastatic tumor cell populations (pN1/2, lymph node metastases). Together with our result that high expression of ITPKA increases motility of tumor cells we conclude that the observed expression of ITPKA early in tumor development increases the metastatic potential of lung adenocarcinoma cells. Therefore, we suggest that ITPKA may be a promising therapeutic molecular target for anti metastatic therapy of lung cancer.
YB‐1 dependent virotherapy in combination with temozolomide as a multimodal therapy approach to eradicate malignant glioma
Authors: Holzmüller Regina , Mantwill Klaus , Haczek Cornelia , Rognoni Emanuel , Anton Martina , Kasajima Atsuko , Weichert Wilko , Treue Denise , Lage Hermann , Schuster Tibor , Schlegel Jürgen , Gänsbacher Bernd , Holm Per S.
Published: November 2010

The human Y‐box binding protein 1 (YB‐1) is known to be a promising target for cancer therapy. We have demonstrated that YB‐1 plays an important role in the adenoviral life cycle by regulating the adenoviral E2‐gene expression. Thus, we studied the oncolytic effect of the recombinant adenovirus Ad‐Delo3‐RGD, in which the transactivation domain CR3 of the E1A protein is ablated to enable viral replication only in YB‐1 positive cancer cells. In vitro Southern Blot analysis and cytopathic effect assays demonstrate high anti‐glioma potency, which was significantly increased in combination with temozolomide (TMZ), daunorubicin and cisplatin. Since vascular endothelial growth factor (VEGF) is thought to promote the hypervascular phenotype of primary, malignant brain tumors, we also tested Ad‐Delo3‐RGD in regard to the inhibition of VEGF expression. Indeed, we found that Ad‐Delo3‐RGD induced VEGF down regulation, which was even amplified under hypoxic conditions. Tumor‐bearing nudemice treated with the YB‐1 dependent oncolytic adenovirus showed significantly smaller tumors than untreated controls. Furthermore, combination therapy with TMZ led to a regression in all treated animals with complete tumor regression in 33 % of analyzed mice, which was verified by bioluminescence imaging and histological studies. In addition, histopathological evaluation revealed enhanced apoptosis and a reduction in tumor vessel formation, indicating that Ad‐Delo3‐RGD has an anti‐angiogenic effect in addition to its oncolytic capacity in vivo. Hence, our results demonstrate that the combination therapy of YB‐1 dependent virotherapy and TMZ is effective in a xenograft glioma mouse model and might be useful in a YB‐1 based clinical setting.