bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Possible Cause of Monozygotic Twinning: Lessons From the 9-Banded Armadillo and From Assisted Reproduction
Authors: Blickstein Isaac , Keith Louis G. 
Published: April 2007

AbstractAvailable hypotheses proposed to explain the mechanism of zygotic splitting fail to explain why monozygotic twins are more prevalent after all methods of assisted reproduction and which structure is likely to control this phenomenon. Arguably, a small proportion of oocytes might have an inborn propensity to undergo splitting upon fertilization leading to the constant prevalence of spontaneous monozygotic conceptions among different populations. Ovarian stimulation would then predictably increase the number of available splitting-prone oocytes and consequently would increase the chance for such oocytes to develop into monozygotic twins, leading to a ‘dose’-dependent relationship between monozygosity rates and the combined effect of infertility treatment. Embryonic division into 2 distinct cell lines begins and accommodates within an intact zona pellucida that controls the process by preventing ill-timed hatching. Human fertilized oocytes are able to undergo 2 binary fissions, just as is the case for the 9-banded armadillo (the only other mammal that produces monozygotic quadruplets) and to give rise to a variety of combinations of monozygotic pregnancies. This hypothetical explanation does not negate the already existing and genetically sound hypotheses, but places them into a broader perspective that respects recent observations from modern infertility treatment.
Parenting Stress and Psychosocial Health in Mothers with Twin–Twin Transfusion Syndrome Managed with Laser Surgery: A Preliminary Study
Authors: Edwards Dawn M. , Gray Peter H. , Soong Barbara , Chan Fung-Yee , Cincotta Robert 
Published: April 2007

AbstractTwin–twin transfusion syndrome (TTTS) is a severe complication of twin pregnancies with high risk for perinatal mortality and long-term morbidity. This cross-sectional cohort study aimed to determine parenting stress and psychosocial health in mothers with a pregnancy complicated by TTTS that had been managed with laser ablation of communicating placental vessels. Questionnaires were sent to the mothers for completion: Parenting Stress Index (PSI), Edinburgh Postnatal Depression Scale (EPDS) and a semi-structured questionnaire related to mental health problems and support received from health professionals. Thirty-seven mothers were sent questionnaires with 32 being returned. The results showed that 47% of women had total scores equal to or greater than the 85th percentile on the PSI, which is considered abnormally high. Twenty-six per cent of mothers had evidence of depression on the EPDS. Mothers of children with prolonged medical conditions or neurological problems had significantly higher scores (p=.011). Parenting stress was not associated with high scores on the EPDS. Medical and midwifery staff were considered to provide high levels of support, with social work providing none or low levels of support. In conclusion, women whose TTTS pregnancy was managed by laser surgery have high levels of parenting stress. As the results showed that parenting stress cannot be predicted at the time of hospitalization, it is suggested that more support should be provided in hospital with further follow-up after discharge.
Mechanical properties and creep behavior of lyocell fibers by nanoindentation and nano-tensile testing
Authors: Lee Seung-Hwan , Wang Siqun , Pharr George M. , Kant Matthew , Penumadu Dayakar 
Published: April 2007

Abstract
Mechanical and time-dependent mechanical properties of lyocell fibers have been investigated as a function of depth at a nano-scale level in longitudinal and transverse directions. The nanoindentation technique was applied and extended to continuous stiffness measurement. Lyo10 and Lyo13 lyocell fibers were investigated. The individual fiber properties were measured using a nano-tensile testing system to obtain reference data for mechanical properties. The hardness and elastic modulus obtained from nanoindentation test are described using two different approaches. The first uses mean values for a depth of 150–300 nm, while the second uses unloading values at the final indentation depth. There is no significant difference between modulus values inferred from nanoindentation and those obtained from single fiber tensile testing. Hardness and elastic modulus values were higher in the longitudinal direction than those in the transverse direction and Lyo13 values were higher than those for Lyo10 in both directions. The time-dependent mechanical properties were also investigated as a function of the holding time. Increasing the holding time led to an increase in indentation displacement and a decrease in hardness. Stress exponents were calculated from the linear relationship between contact stress and contact strain using a power-law creep equation.
Changes in physical, mechanical and chemical properties of wood during sterilisation by gamma radiation
Authors: Despot Radovan , Hasan Marin , Brischke Christian , Welzbacher Christian Robert , Rapp Andreas Otto 
Published: April 2007

Abstract
Gamma irradiation, which is an easy, fast and effective method for wood sterilisation, changes molecular structures not only in pest cells, but also in wood cell walls. Radiation-induced depolymerisation causes significant changes in some properties of wood crucial for restoration and for laboratory testing of wood-preservative effectiveness, as demonstrated by experimental data. The influence of gamma radiation on maximum swelling (αMAX), resistance to impact milling (RIM), and the total amount of water-soluble carbohydrates (TSC) was investigated. Cobalt (60Co) was used as a gamma source and Scots pine wood (Pinus sylvestris L.) was irradiated at doses of 30, 90 and 150 kGy. A strong linear correlation was found between TSC and radiation dosage. Leached irradiated specimens showed significantly greater TSC content than non-irradiated controls. RIM decreased significantly and linearly with increasing radiation dosage. After leaching, the linearity between these parameters improved. Gamma radiation had no significant effect on αMAX and the time elapsed after irradiation did not influence αMAX, RIM or TSC.
Editorial
Authors: Spranger Tade M 
Published: April 2007

AbstractBoth the confidence of the international scientific community and the public hopes risen by stem cell technology were shaken one year ago by what is called the Korean stem cell scandal. The forgery conducted by one of Korea's major scientists led to several fundamental questions. Some of them refer to ethical aspects, while others concern legal facets: Are law and ethics really able to control scientific research in the field of biotechnology and biomedicine ? Which effects are exerted by the ”publish or perish” policy as well as the commercialisation of basic research on the quality of scientific work ? Is the practical relevance of stem cell research overestimated ? Has the relationship between principal researchers and their staff to be reviewed or even controlled according to tightened ethical and legal standards ?
Enhancement as a Legal Challenge
Authors: Beck Susanne 
Published: April 2007

Abstract“What better way to start the new year than with a new you?” comments Liz Dale, Transform's commercial manager, on the recent British fashion to give away cosmetic surgeries for Christmas. Creating a “new you” has become a remarkable development in the western world. In 2005, around 1 500 000 surgical cosmetic procedures have taken place among Americans, and almost 3 300 000 were treated with Botox. In many countries cosmetic surgery is one of the few medical areas which is still profitable. But beauty is just one human characteristic amenable perfecting: the enhancement of mental abilities with drugs has already become a serious problem in universities across the U.S., and the progress of genetic technology might pave the way to create a perfect next generation.
Biotechnology Investment in Vietnam
Authors: Hilmer Sarah E 
Published: April 2007

AbstractOn 11 January 2007 Vietnam became the World Trade Organisation's (WTO) 150th member. WTO members completed their task on 26 October 2006 by accepting the documents indicating Vietnam's obligations and rights. The documents reached General Council which approved Vietnam's membership on the 7 November 2006. Vietnam informed the WTO on 12 December 2006 that it has ratified its membership agreement, and it thereby became a full member after 30 days of ratifying the agreement, which was on the 11 January 2007.
Turbidity Tolerances of Great Lakes Coastal Wetland Fishes
Authors: Trebitz Anett S. , Brazner John C. , Brady Valerie J. , Axler Richard , Tanner Danny K. 
Published: April 2007

Abstract
Despite recent interest in assessing the condition of fish assemblages in Great Lakes coastal wetlands and a concern for increasing turbidity as a major stressor pathway influencing these ecosystems, there is little information on fish tolerance or intolerance to turbidity on which to base wetland assessment metrics. Existing studies have borrowed tolerance designations from the stream literature, but they have not confirmed that the designations apply to Great Lakes wetlands or that designations based on tolerance to degradation in general apply to turbidity in particular. We used a published graphical method to determine turbidity tolerances of Great Lakes fishes based on their pattern of occurrence and relative abundance across coastal wetlands spanning a turbidity gradient. Fish composition data were obtained from fyke-net and electrofishing surveys of 75 wetlands along the U.S. shoreline of the Laurentian Great Lakes, representing a turbidity range of approximately 0–110 nephelometric turbidity units (NTU). Turbidity levels of 10, 25, and 50 NTU (corresponding to the thresholds in use for state water quality criteria) were used to separate fish into tolerance classes. We found that the turbidity tolerances of many species in Great Lakes wetlands differed from the published tolerances to general degradation in streams. Also, the tolerance levels for many species were unclear owing to the species' infrequent occurrence. Although many of the wetlands sampled had quite low turbidity, a large proportion of the fish species were tolerant or moderately tolerant to turbidity and very few were intolerant, suggesting that enumerating intolerant species may not be a useful metric or that the metric should be expanded to include moderately intolerant species. Our study lays the foundation for additional turbidity indicator development efforts for Great Lakes coastal wetlands.
An Improved Sibling Model for Forecasting Chum Salmon and Sockeye Salmon Abundance
Authors: Haeseker Steven L. , Dorner Brigitte , Peterman Randall M. , Su Zhenming 
Published: April 2007

Abstract
The sibling model is often one of the best methods for calculating preseason forecasts of adult return abundance (recruits) for populations of Pacific salmon Oncorhynchus spp. This model forecasts abundance of a given age-class for a given year based on the abundance of the previous age-class in the previous year. When sibling relations fit historical data well, the sibling model generally performs better than other forecasting methods, such as stock–recruitment models. However, when sibling relations are weak, better forecasts are obtained by other models, such as naïve models that simply use an historical average. We evaluated the performance of a hybrid model that used quantitative criteria for switching between a sibling model and a naïve model when generating forecasts for 21 stocks of chum salmon O. keta and 37 stocks of sockeye salmon O. nerka in the northeastern Pacific Ocean. Compared with the standard sibling model, the hybrid model reduced the root mean square error (RMSE) of forecasts by an average of 27% for chum salmon stocks and 28% for sockeye salmon stocks. Compared with a naïve model, the hybrid model reduced the RMSE of forecasts by an average of 16% for chum salmon stocks and 15% for sockeye salmon stocks. Our results suggest that hybrid models can improve preseason forecasts and management of these two species.
Effect of Omega‐3 Fatty Acid Supplementation on the Arachidonic Acid: Eicosapentaenoic Acid Ratio
Authors: Burns Tammy , Maciejewski Stephanie R. , Hamilton William R. , Zheng Margaret , Mooss Aryan N. , Hilleman Daniel E. 
Published: April 2007

Study Objectives. To determine the baseline arachidonic acid: eicosapentaenoic acid (AA:EPA) ratio in patients with coronary artery disease and healthy subjects, and whether supplementation of omega‐3 fatty acids, administered as fish oil capsules, affects this ratio.Design. Prospective, open‐label trial.Setting. University‐affiliated cardiology clinic.Subjects. Thirty patients with stable coronary artery disease (CAD) and 30 healthy subjects.Intervention. All participants received omega‐3 fatty acids 1.5 g/day for 4 weeks, followed by 3 g/day for an additional 4 weeks.Measurements and Main Results. For each participant, a lipid profile was determined at baseline and after 4 weeks of treatment with each dose. Other laboratory results analyzed were serum AA:EPA ratios, high‐sensitivity C‐reactive protein (hs‐CRP) levels, and blood glucose levels. Mean ± SD baseline AA:EPA ratios were 39.6 ± 19.0 in healthy subjects and 23.7 ± 12.5 in patients with CAD. These ratios decreased significantly in both groups after treatment with 1.5 g/day of omega‐3 fatty acids: 9.0 ± 4.2 in healthy subjects and 10.3 ± 8.8 in patients with CAD. After treatment with 3 g/day, the ratios were further reduced: 5.1 ± 3.2 in healthy subjects and 4.9 ± 2.6 in patients with CAD. Supplementation with omega‐3 fatty acids did not significantly affect hs‐CRP, high‐density lipoprotein cholesterol, low‐density lipoprotein cholesterol, or blood glucose levels. Triglyceride levels were not reduced in patients with CAD but were significantly decreased in healthy subjects (by 20% decrease with omega‐3 fatty acids 1.5 g/day and by 32% decrease with 3 g/day).Conclusion. Treatment with omega‐3 fatty acids significantly reduced AA:EPA ratios in both healthy subjects and in patients with stable CAD. The treatment had no effect on hs‐CRP levels in either group, and it reduced triglyceride levels in healthy subjects but not in patients with CAD.
Reengineering Clinical Operations in a Medical Practice to Optimizethe Management of Anemia of Chronic Kidney Disease
Authors: Joy Melanie S. , Candiani Corina , Vaillancourt Beverly A. , Chin Hyunsook , Hogan Susan L. , Falk Ronald J. 
Published: April 2007

Objectives. To describe the clinic design, clinical evaluations, and treatment approaches used in a multidisciplinary clinic for management of anemia of chronic kidney disease (CKD), and to evaluate several selected clinical outcomes associated with this approach to anemia management.Setting. University‐affiliated, division of nephrology, outpatient multidisciplinary model CKD clinic headed by a clinical pharmacist.Patients. One hundred sixty‐six patients with anemia of CKD who were referred by nephrologists and primary care providers to the multidisciplinary clinic from March 1, 2002–July 31, 2004.Measurements and Main Results. Patients received darbepoetin alfa dosed on an every‐other‐week basis. If patients were already receiving once‐weekly recombinant human erythropoietin (r‐HuEPO), the darbepoetin alfa dose was calculated by using the darbepoetin alfa package insert conversion table. If patients were naïve to previous erythropoietic therapy, the darbepoetin alfa dose was either 60 μg or 0.7 μg/kg. The dose and frequency of darbepoetin alfa and oral iron supplements were adjusted to achieve the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (K/DOQI) targets for hemoglobin levels and iron measures. The primary outcome analyzed was the proportion of patients with at least 30 days of treatment who achieved a target hemoglobin level of 11.0 g/dl or greater. Of 128 patients who received at least 30 days of treatment, 100 (78%) attained the hemoglobin level (mean ± SD 11.7 ± 7 g/dl). Ninety‐nine of 128 patients were originally naïve to erythropoietic therapy; 77 (78%) of these 99 patients achieved the hemoglobin target in a mean ± SD of 7.9 ± 7.5 weeks. These data contrast with the data of 29 patients seen in the year previous to the reengineered clinic process, whereby only 12 (41%) of these comparable patients reached hemoglobin target with r‐HuEPO therapy. Of the 77 previously erythropoietic‐naïve patients, 82% were receiving darbepoetin alfa every other week, 14% every 3 weeks, and 4% every 4 weeks at the time the hemoglobin target was achieved. Oral iron administration significantly increased the chance of achieving the K/DOQI targets for hemoglobin and iron.Conclusion. Redefining roles and practices of members of a clinical practice and reengineering processes for anemia management were effective in achieving and maintaining target hemoglobin and iron levels.
Indolyl substituted 4-oxobut-2-enoic acids. Synthesis and aza-Michael additions
Authors: Berkeš Dušan , Koren̆ová Anna , Šafár̆ Peter , Horváthová Helena , Prónayová Nadežda 
Published: April 2007

Abstract
The synthesis of three new substituted 4-hetereoaryl-4-oxobut-2-enoic acids with indole ring substitutedin positions 3-, 5- and 7- is described. The addition of these Michael acceptors to 4-(1-phenylsulphonylpyrrol-3-yl)-4-oxobut-2-enoic acid in conjugate addition was explored using both racemic and chiral amines. In tandem with the crystallization-induced asymmetric transformation (CIAT) protocol the effective methodology for the synthesis of enantiomerically highly enriched substituted 2-amino-4-heteroaryl-4-oxobutanoic acids as multifunctional homotryptophan analogues was developed.
Glycoproteomics Using Chemical Immobilization
Authors: Zhang Hui 
Published: April 2007

AbstractProtein glycosylation is prevalent in proteins destined for extracellular environments, e.g., transmembrane proteins, cell surface proteins, and secreted proteins in tissues and body fluids. These also are the proteins that are most easily accessible for diagnostic and therapeutic purposes. This unit describes methods for solid‐phase extraction of glycopeptides and subsequent identification of glycopeptides as well as glycosylation sites. The extraction is based on the conjugation of glycopeptides to a solid support, using hydrazide chemistry, and the specific release of formerly glycosylated peptides. The recovered peptides are then identified by tandem mass spectrometry. The methods are applied to the analysis of proteins from cells, body fluids, and tissues.
Histochemical Methods for the Detection of Apoptosis in the Nervous System
Authors: Oo Tinmarla Frances , Burke Robert E. 
Published: April 2007

AbstractNeuroscientists often need to detect neuron death at the light microscope level in tissue sections derived from animal models of neurological disease. In many instances there is a need to detect apoptosis, the most common morphology of programmed cell death. This unit provides two protocols for the detection of apoptosis by immunostaining for either activated forms of caspases or their cleavage products. When used in conjunction with nuclear dyes, these protocols permit visualization not only of caspase activation, but also the nuclear chromatin clumps characteristic of apoptosis. The first protocol utilizes peroxidase‐mediated chromogen deposition to visualize antibodies by brightfield microscopy. The second protocol utilizes fluorophores to visualize antibodies by epifluorescence. Double immunofluorescence labeling can be performed to identify the phenotype of cells in which caspases are activated. Not all cell death is apoptotic. Therefore, a third protocol is presented for suppressed silver staining, a useful method to screen for all morphologic forms of cell death.
Lentiviral Strategies for RNAi Knockdown of Neuronal Genes
Authors: Crittenden Jill R. , Heidersbach Amy , McManus Michael T. 
Published: April 2007

AbstractRNA interference (RNAi) refers to the process by which 21‐ to 23‐nucleotide short interfering RNAs (siRNAs) mediate post‐transcriptional degradation of homologous mRNA transcripts. This process is carried out by an endogenous pathway that centers on the use of endogenously encoded small RNAs, and can be hijacked to knock down the expression of any target protein by introducing a specific siRNA into a cell. Stable knockdown can be obtained by constitutive expression of the siRNA from the host chromosome. Retroviruses, such as lentivirus, provide a convenient vector by which to integrate RNAi expression constructs. Lentiviruses can infect nondividing cells, thereby allowing knockdown in cells such as mature neurons. This unit provides methods to design and clone siRNAs into a lentiviral vector. Additional protocols describe production and titering of the lentivirus, as well as safety testing. Finally, methods are provided for infecting neurons in culture and in vivo with RNAi lentivirus.
Overview of Animal Models of Schizophrenia
Authors: Powell Susan B. , Geyer Mark A. 
Published: April 2007

AbstractAnimal models of schizophrenia may increase the understanding of the neurological abnormalities associated with the disorder and aid in the development of rational pharmacological treatments. Rather than attempting to model the entire syndrome of schizophrenia, a more biologically oriented approach to animal models has been to focus on specific symptoms of schizophrenia that are more objectively measured in the clinical population and more directly translatable to animals (e.g., observables or endophenotypes). This overview focuses on behavioral measures that have been investigated in rodent models of schizophrenia with varying degrees of predictive, etiological, and construct validity. Because of the severity of cognitive deficits in schizophrenia and their resistance to current treatments, there is a need to develop animal models specific to the cognitive symptoms of schizophrenia. In light of this need, this overview discusses rodent models of cognition with relevance to the core cognitive deficits observed in schizophrenia.
Production of Recombinant Adeno‐Associated Viral Vectors for In Vitro and In Vivo Use
Authors: Choi Vivian W. , Asokan Aravind , Haberman Rebecca A. , Samulski Richard Jude 
Published: April 2007

AbstractAdeno‐associated virus is a nonpathogenic human virus that has been developed into a gene‐delivery vector due to its high efficiency of infection in many different cell types and its ability to persist and lead to long‐term gene expression. The vector is also a valuable tool in molecular biology experiments. This unit describes efficient methods to generate high‐titer, research‐grade, adenovirus‐free, recombinant single‐stranded and self‐complementary adeno‐associated virus in various serotypes, along with methods to quantify the viral vectors.
Histopathology in Mouse Metabolic Investigations
Authors: Mark Manuel , Teletin Marius , Antal Cristina , Wendling Olivia , Auwerx Johan , Heikkinen Sami , Khetchoumian Konstantin , Argmann Carmen A. , Dgheem Mounzer 
Published: April 2007

AbstractDue to the small size of the mouse, evaluating its clinical phenotype is sometimes problematic. In contrast, mouse models are readily accessible to post‐mortem analyses at any time during the course of a disease and prior to its clinical onset. RNA, protein, and histological analyses following sacrifice represent a powerful means to identify affected cell types and molecular events underlying the altered phenotype, and therefore to understanding the signaling or metabolic pathways involved. In this unit, an overview of post‐mortem analyses is provided with a strong emphasis on the principles of routine histology, including tissue fixation, processing, embedding, and staining with hematoxylin and eosin. There are also several protocols for staining with specialized histological stains used in the metabolic field to detect intracellular lipids, intracellular lipid “ghosts”, cholesterol esters, polysaccharides, mitochondria, pathological collagen deposits, and atherosclerotic plaques.