bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characteristics and dynamics of a regional moose Alces alces population in the northeastern United States
Authors: Musante Anthony R. , Pekins Peter J. , Scarpitti David L. 
Published: July 2010

AbstractAbundance indices suggested that the moose Alces alces population in northern New Hampshire was stable despite favourable habitat and conservative harvest. Causes and rates of mortality were unknown because moose reproduction and survival was unstudied in the region. Our study was designed to investigate the dynamics of the regional population in 2002‐2005. A total of 92 moose (33 cows and 59 calves) were captured and fitted with radio‐collars (VHF = 83, GPS = 9). Parturition ranged from 8 May to 13 July (median = 19 May) with 78% of births occurring during 13‐27 May. Calving rate of yearlings and adults (> 2 years old) averaged 30 and 85%, respectively; twinning rate was 11%. Analysis of reproductive data from harvested cows (1988‐2004) indicated that the average weight of adult cows increased but their corpora lutea count declined from ∼ 1.4 to 1.2/cow. Both ovulation rate and average weight of yearling cows declined about 25 and 4%, respectively. There were 39 mortalities (49% calves) with winterkill/parasite (41%), vehicle collision (26%) and hunting (18%) as the leading causes. Major sources of mortality of radio‐marked cows were human‐related; survival was 0.87. Annual calf survival was 0.45. Unmarked calf (0‐2 months of age) survival was 0.71 with 76% of mortality in the first month of life. Radio‐marked calves (∼ 7‐12 months of age) had a survival rate of 0.67; 74% of the mortality was winterkill/parasite related. Calf mortality was concentrated (88%) in late winter‐early spring. The unseasonably warm and snowless fall in 2001 probably favoured high tick transmission and increased tick loads on moose that resulted in high calf mortality (0.51) and measurable cow mortality (10%) in mild winter‐spring 2002. Documentation of substantial tick‐related mortality of radio‐marked moose calves was unique to this study. The stability of the moose population probably reflects the variation in annual recruitment and lower fecundity of yearling cows associated with heavy infestations and epizootics of winter tick. Given that fertility, calving rate and body condition of adult cows, and summer calf survival are annually high, the population should recover from tick epizootics that periodically inhibit population growth.
Further development and validation of the Unhelpful Thoughts and Beliefs About Stuttering (UTBAS) scales: relationship to anxiety and social phobia among adults who stutter
Authors: Iverach Lisa , Menzies Ross , Jones Mark , O'Brian Sue , Packman Ann , Onslow Mark 
Published: July 2010

Abstract Background: In an initial validation study, the Unhelpful Thoughts and Beliefs About Stuttering (UTBAS I) scale, demonstrated excellent psychometric properties as a self‐report measure of the frequency of unhelpful cognitions associated with social anxiety for adults who stutter. Aims: The aim was to further validate the original UTBAS I scale, and to develop two additional scales to assess beliefs (UTBAS II) and anxiety (UTBAS III) associated with negative thoughts. Methods & Procedures: A total of 140 adults seeking speech‐restructuring treatment for stuttering completed the original UTBAS I scale, the newly developed UTBAS II and III scales, and self‐report measures of psychological functioning. Participants also completed a first‐stage screener for the presence of anxious personality disorder, and a diagnostic assessment to evaluate the presence of social phobia, according to criteria of the Diagnostic and Statistical Manual of Mental Disorders (DSM‐IV) and the International Classification of Diseases (ICD‐10). Outcomes & Results: The mean UTBAS I score for the present sample did not differ significantly from the mean score reported in the original UTBAS I validation study. Convergent validity was confirmed by significant correlations between the UTBAS Total score and all anxiety‐related measures. Discriminant validity was established by the absence of strong correlations between the UTBAS Total score and some of the self‐report measures of unrelated constructs, although it was found to tap into the negative cognitions associated with depression and life problems. Approximately one‐quarter of participants met criteria for a diagnosis of DSM‐IV or ICD‐10 social phobia (23.5% and 27.2% respectively), and nearly one‐third met first‐stage screening criteria for anxious personality disorder (30%). The mean UTBAS scores for participants who met criteria for these disorders were significantly higher than scores for participants who did not, confirming known‐groups validity. Conclusions & Implications: The present study demonstrates the validity and utility of the UTBAS scales in assessing negative cognitions associated with speech‐related anxiety among adults who stutter. Results also confirm previous evidence of a high rate of social phobia among adults who stutter, and reveal that the UTBAS discriminates between adults with and without social phobia. In terms of clinical applications, the UTBAS scales could be used to screen for indicators of social phobia among adults who stutter, and may prove useful in identifying negative cognitions which have the potential to impact treatment outcomes.
Effects of snow, snowmelting and refreezing processes on air–sea-ice CO2 flux
Authors: Nomura Daiki , Yoshikawa-Inoue Hisayuki , Toyota Takenobu , Shirasawa Kunio 
Published: July 2010

AbstractThe air–sea-ice CO2 flux was measured in the ice-covered Saroma-ko, a lagoon on the northeastern coast of Hokkaido, Japan, using a chamber technique. The air–sea-ice CO2 flux ranged from −1.8 to +0.5 mg C m−2 h−1 (where negative values indicate a sink for atmospheric CO2). The partial pressure of CO2 (pCO2) in the brine of sea ice was substantially lower than that of the atmosphere, primarily because of the influence of the under-ice plume from the Saromabetsu river located in the southeastern part of the lagoon. This suggests that the brine had the ability to take up atmospheric CO2 into the sea ice. However, the snow deposited over the sea ice and the superimposed ice that formed from snowmelting and refreezing partially blocked CO2 diffusion, acting as an impermeable medium for CO2 transfer. Our results suggest that the air–sea-ice CO2 flux was dependent not only on the difference in pCO2 between the brine and the overlying air, but also on the status of the ice surface. These results provide the necessary evidence for evaluation of the gas exchange processes in ice-covered seas.
Synthesis of 6-PEtN-α-D-GalpNAc-(1–>6)-β-D-Galp-(1–>4)-β-D-GlcpNAc-(1–>3)-β-D-Galp-(1–>4)-β-D-Glcp, a Haemophilus influenzae lipopolysacharide structure, and biotin and protein conjugates thereof
Authors: Sundgren Andreas , Lahmann Martina , Oscarson Stefan 
Published: July 2010

Background: In bacteria with truncated lipopolysaccharide structures, i.e., lacking the O-antigen polysaccharide part, core structures are exposed to the immune system upon infection and thus their use as carbohydrate surface antigens in glycoconjugate vaccines can be considered and investigated. One such suggested structure from Haemophilus influenzae LPS is the phosphorylated pentasaccharide 6-PEtN-α-D-GalpNAc-(1→6)-β-D-Galp-(1→4)-β-D-GlcpNAc-(1→3)-β-D-Galp-(1→4)-β-D-Glcp.Results: Starting from a spacer-containing lactose derivative a suitably protected lacto-N-neotetraose tetrasaccharide structure was constructed through subsequential couplings with two thioglycoside donors, a glucosamine residue followed by a galactose derivative, using NIS/AgOTf as promoter. Removal of a silyl protecting group at the primary position of the non-reducing end residue afforded an acceptor to which the terminal α-galactosamine moiety was introduced using a 2-azido bromo sugar and halide assisted coupling conditions. Global deprotection afforded the non-phosphorylated target pentasaccharide, whereas removal of a silyl group from the primary position of the non-reducing end residue produced a free hydroxy group which was phosphorylated using H-phosphonate chemistry to yield the phosphoethanolamine-containing protected pentasaccharide. Partial deprotection afforded the phosphorylated target pentasaccharide with a free spacer amino group but with a protected phosphoethanolamino group. Conjugation of the spacer amino group to biotin or dimethyl squarate followed by deprotection of the phosphoethanolamino group and, in the case of the squarate derivative, further reaction with a protein then afforded the title conjugates.Conclusion: An effective synthesis of a biologically interesting pentasaccharide structure has been accomplished. The target pentasaccharide, an α-GalNAc substituted lacto-N-neotetraose structure, comprises a phosphoethanolamine motif and a spacer aglycon. Through the spacer, biotin and protein conjugates of the title compound have been constructed to allow further use in biological experiments.
Direct Presentation Regulates the Magnitude of the CD8+ T Cell Response to Cell-Associated Antigen through Prolonged T Cell Proliferation
Authors: Tatum Angela M. , Watson Alan M. , Schell Todd D. 
Published: July 2010

AbstractThe magnitude and complexity of Ag-specific CD8+ T cell responses is determined by intrinsic properties of the immune system and extrinsic factors, such as vaccination. We evaluated mechanisms that regulate the CD8+ T cell response to two distinct determinants derived from the same protein Ag, SV40 T Ag (T Ag), following immunization of C57BL/6 mice with T Ag-transformed cells. The results show that direct presentation of T cell determinants by T Ag-transformed cells regulates the magnitude of the CD8+ T cell response in vivo but not the immunodominance hierarchy. The immunodominance hierarchy was reversed in a dose-dependent manner by addition of excess naive T cells targeting the subdominant determinant. However, T cell competition played only a minor role in limiting T cell accumulation under physiological conditions. We found that the magnitude of the T cell response was regulated by the ability of T Ag-transformed cells to directly present the T Ag determinants. The hierarchy of the CD8+ T cell response was maintained when Ag presentation in vivo was restricted to cross-presentation, but the presence of T Ag-transformed cells capable of direct presentation dramatically enhanced T cell accumulation at the peak of the response. This enhancement was due to a prolonged period of T cell proliferation, resulting in a delay in T cell contraction. Our findings reveal that direct presentation by nonprofessional APCs can dramatically enhance accumulation of CD8+ T cells during the primary response, revealing a potential strategy to enhance vaccination approaches.
TLR9-Targeted Biodegradable Nanoparticles as Immunization Vectors Protect against West Nile Encephalitis
Authors: Demento Stacey L. , Bonafé Nathalie , Cui Weiguo , Kaech Susan M. , Caplan Michael J. , Fikrig Erol , Ledizet Michel , Fahmy Tarek M. 
Published: July 2010

AbstractVaccines that activate humoral and cell-mediated immune responses are urgently needed for many infectious agents, including the flaviviruses dengue and West Nile (WN) virus. Vaccine development would be greatly facilitated by a new approach, in which nanoscale modules (Ag, adjuvant, and carrier) are assembled into units that are optimized for stimulating immune responses to a specific pathogen. Toward that goal, we formulated biodegradable nanoparticles loaded with Ag and surface modified with the pathogen-associated molecular pattern CpG oligodeoxynucleotides. We chose to evaluate our construct using a recombinant envelope protein Ag from the WN virus and tested the efficiency of this system in eliciting humoral and cellular responses and providing protection against the live virus. Animals immunized with this system showed robust humoral responses polarized toward Th1 immune responses compared with predominately Th2-biased responses with the adjuvant aluminum hydroxide. Immunization with CpG oligodeoxynucleotide-modified nanoparticles resulted in a greater number of circulating effector T cells and greater activity of Ag-specific lymphocytes than unmodified nanoparticles or aluminum hydroxide. Ultimately, compared with alum, this system offered superior protection in a mouse model of WN virus encephalitis.
Antireflective Nanoparticle Arrays Enhance the Efficiency of Silicon Solar Cells
Authors: Wan Dehui , Chen Hsuen‐Li , Tseng Te‐Chen , Fang Cheng‐Yi , Lai Yu‐Shen , Yeh Fang‐Yao 
Published: July 2010

AbstractIn this study, the phenomenon of light trapping in Si solar cells coated with metal (Au) and dielectric (TiO2, SiO2) nanoparticles (NPs) is systematically investigated. In contrast to previous reports, herein it is proposed that the photocurrent enhancement of solar cells should be attributed to the limited antireflection ability of the Au NP arrays. In other words, the Au NP arrays might not enhance the absorption of the active layer in cells when no light is reflected from the air–substrate interface. Therefore, the Au NPs are replaced with dielectric NPs, which possess lower extinction coefficients, and then the antireflection property of the TiO2 NP arrays is optimized. A simple, rapid, and cheap solution‐based method is used to prepare close‐packed TiO2 NP films on Si solar cells; these devices exhibit a uniform and remarkable increase (ca. 30%) in their photocurrents. To the best of the authors’ knowledge, this uniform photocurrent enhancement is greater than those obtained from previously reported metal and dielectric NP–enhanced Si wafer‐based solar cells.
Synthesis of poly(ε‐caprolactone)/clay nanocomposites using polyhedral oligomeric silsesquioxane surfactants as organic modifier and initiator
Authors: Hossain Md. D. , Yoo Youngjae , Lim Kwon T. 
Published: July 2010

AbstractPoly(ε‐caprolactone)/clay nanocomposites were synthesized by in situ ring‐opening polymerization of ε‐caprolactone in the presence of montmorillonite modified by hydroxyl functionalized, quaternized polyhedral oligomeric silsesquioxane (POSS) surfactants. The octa(3‐chloropropyl) polyhedral oligomeric silsesquioxane was prepared by hydrolytic condensation of 3‐chloropropyltrimethoxysilane, which was subsequently quaternized with 2‐dimethylaminoethanol. Montmorillonite was modified with the quaternized surfactants by cation exchange reaction. Bulk polymerization of ε‐caprolactone was conducted at 110°C using stannous octoate as an initiator/catalyst. Nanocomposites were analyzed by X‐ray diffraction, transmission electron microscopy, thermo gravimetric analysis, and differential scanning calorimetry. Hydroxyl functionalized POSS was employed as a surface modifier for clay which gives stable clay separation for its 3‐D structure and also facilitates the miscibility of polymer with clay in the nanocomposites due to the star architecture. An improvement in the thermal stability of PCL was observed even at 1 wt % of clay loading. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Novel semisynthetic method for generating full length β‐amyloid peptides
Authors: Bockhorn Jessica J. , Lazar Kristi L. , Gasser Adam J. , Luther Laura M. , Qahwash Isam M. , Chopra Neeraj , Meredith Stephen C. 
Published: July 2010

AbstractBacterial expression of full length β‐amyloid (Aβ) is problematic because of toxicity and poor solubility of the expressed protein, and a strong tendency of Met35 to become oxidized in inclusion bodies. We have developed a semisynthetic method in which Aβ1‐29 is expressed in bacteria as part of a fusion protein with a C‐terminal intein and Chitin‐Binding Domain (CBD). There is also a single residue, N‐terminal Met extension. The protein, Met‐Aβ1‐29‐Intein‐CBD, is well expressed and highly water‐soluble. After binding of the expressed protein to Chitin beads, treatment with sodium 2‐mercapto‐ethane sulfonate (MESNA) yields Met‐Aβ1‐29‐MESNA, with a C‐terminal thioester suitable for native chemical ligation. Met‐Aβ1‐29‐MESNA is first subjected to CNBr cleavage, which removes the N‐terminal Met residue, but leaves the thioester intact. We synthesized NH2‐A30C‐Aβ30‐40, which has an N‐terminal Cys residue and is the partner for native chemical ligation with Met‐Aβ1‐29‐MESNA. Native chemical ligation proceeds rapidly and efficiently (>90% yield) to give A30C‐Aβ1‐40. The final step is selective desulfurization using Raney‐Ni, which also proceeds rapidly and efficiently (>90% yield) to give native sequence Aβ1‐40. Overall, this system is highly efficient, and can yield ≈8–10 mg of pure Aβ1‐40 from one liter of bacterial culture medium. This procedure is adaptable for producing other Aβ peptides. We have also expressed an Aβ construct bearing a point mutation associated with one type of familial Alzheimer's Disease, the Iowa mutation, i.e., Met‐D23N‐Aβ1‐29‐Intein‐CBD. Since expression of the intein‐containing fusion protein is robust in minimal media as well as standard enriched media, this procedure also can be readily modified for incorporating 15N or 13C labels for NMR. Future work will also include extending this system to longer Aβ peptides, such as Aβ1‐42. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 94: 511–520, 2010.
Comparison analysis of primary ligand‐binding sites in seven‐helix membrane proteins
Authors: Pabuwal Vagmita , Li Zhijun 
Published: July 2010

AbstractSeven‐helix transmembrane proteins, including the G‐protein‐coupled receptors (GPCRs), mediate a broad range of fundamental cellular activities through binding to a wide range of ligands. Understanding the structural basis for the ligand‐binding selectivity of these proteins is of significance to their structure‐based drug design. Comparison analysis of proteins' ligand‐binding sites provides a useful way to study their structure‐activity relationships. Various computational methods have been developed for the binding‐site comparison of soluble proteins. In this work, we applied this approach to the analysis of the primary ligand‐binding sites of 92 seven‐helix transmembrane proteins. Results of the studies confirmed that the binding site of bacterial rhodopsins is indeed different from all GPCRs. In the latter group, further comparison of the binding sites indicated a group of residues that could be responsible for ligand‐binding selectivity and important for structure‐based drug design. Furthermore, unexpected binding‐site dissimilarities were observed among adrenergic and adenosine receptors, suggesting that the percentage of the overall sequence identity between a target protein and a template protein alone is not sufficient for selecting the best template for homology modeling of seven‐helix membrane proteins. These results provided novel insight into the structural basis of ligand‐binding selectivity of seven‐helix membrane proteins and are of practical use to the computational modeling of these proteins. © 2010 Wiley Periodicals, Inc. Biopolymers 95: 31–38, 2011.
Correlation between anatomical characteristics of ethanol organosolv pretreated Buddleja davidii and its enzymatic conversion to glucose
Authors: Hallac Bassem B. , Ray Michael , Murphy Richard J. , Ragauskas Arthur J. 
Published: July 2010

AbstractBuddleja davidii is a unique biomass that has many attractive agroenergy features, especially its wide range of growth habitat. The anatomical characteristics of B. davidii were investigated before and after ethanol organosolv pretreatment (one of the leading pretreatment technologies) in order to further understand the alterations that occur to the cellular structure of the biomass which can then be correlated with its enzymatic digestibility. Results showed that the ethanol organosolv pretreatment of B. davidii selectively removes lignin from the middle lamella (ML), which does not significantly disrupt the crystalline structure of cellulose. The removal of ML lignin is a major factor in enhancing enzymatic cellulose‐to‐glucose hydrolysis. The pretreatment also causes cell deformation, resulting in cracks and breaks in the cell wall. These observations, together with characterization analysis of the cell wall polymer material, lend support to the hypothesis that the physical distribution of lignin in the biomass matrix is an important structural feature affecting biomass enzymatic digestibility. Biotechnol. Bioeng. 2010;107: 795–801. © 2010 Wiley Periodicals, Inc.
Recreating the perivascular niche ex vivo using a microfluidic approach
Authors: Carrion Bita , Huang Carlos P. , Ghajar Cyrus M. , Kachgal Suraj , Kniazeva Ekaterina , Jeon Noo Li , Putnam Andrew J. 
Published: July 2010

AbstractStem cell niches are composed of numerous microenvironmental features, including soluble and insoluble factors, cues from other cells, and the extracellular matrix (ECM), which collectively serve to maintain stem cell quiescence and promote their ability to support tissue homeostasis. A hallmark of many adult stem cell niches is their proximity to the vasculature in vivo, a feature common to neural stem cells, mesenchymal stem cells (MSCs) from bone marrow and adipose tissue, hematopoietic stem cells, and many tumor stem cells. In this study, we describe a novel 3D microfluidic device (MFD) as a model system in which to study the molecular regulation of perivascular stem cell niches. Endothelial cells (ECs) suspended within 3D fibrin gels patterned in the device adjacent to stromal cells (either fibroblasts or bone marrow‐derived MSCs) executed a morphogenetic process akin to vasculogenesis, forming a primitive vascular plexus and maturing into a robust capillary network with hollow well‐defined lumens. Both MSCs and fibroblasts formed pericytic associations with the ECs but promoted capillary morphogenesis with distinct kinetics. Biochemical assays within the niche revealed that the perivascular association of MSCs required interaction between their α6β1 integrin receptor and EC‐deposited laminin. These studies demonstrate the potential of this physiologically relevant ex vivo model system to study how proximity to blood vessels may influence stem cell multipotency. Biotechnol. Bioeng. 2010;107: 1020–1028. © 2010 Wiley Periodicals, Inc.
Glycosyltransferases and their Assays
Authors: Wagner Gerd K. , Pesnot Thomas 
Published: July 2010

AbstractGlycosyltransferases (GTs) are a large family of enzymes that are essential in all domains of life for the biosynthesis of complex carbohydrates and glycoconjugates. GTs catalyse the transfer of a sugar from a glycosyl donor to a variety of acceptor molecules, for example, oligosaccharides, peptides, lipids or small molecules. Such glycosylation reactions are central to many fundamental biological processes, including cellular adhesion, cell signalling and bacterial‐ and plant‐cell‐wall biosynthesis. GTs are therefore of significant interest as molecular targets in chemical biology and drug discovery. In addition, GTs have found wide application as synthetic tools for the preparation of complex carbohydrates and glycoconjugates. In order to exploit the potential of GTs both as molecular targets and synthetic tools, robust and operationally simple bioassays are essential, especially as more and more protein sequences with putative GT activity but unknown biochemical function are being identified. In this minireview, we give a brief introduction to GT biochemistry and biology. We outline the relevance of GTs for medicinal chemistry and chemical biology, and describe selected examples for recently developed GT bioassays, with a particular emphasis on fluorescence‐based formats.