bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variations in general practice prescribing costs and implications for budget setting
Authors: Healey Andrew T. , Yule Brian F. , Reid John P. 
Published: May 2007

AbstractIndicative prescribing amounts, and the equivalent prescribing element of funds in the case of fundholding practices, are now an established part of UK general practice. This paper examines the implications of variations in GP prescribing behaviour for the determination of prescribing budgets. Using regression analysis, the extent to which variations in total practice prescribing costs can be explained by factors suggested for inclusion in a weighted capitation formula is established. The results indicate that 97% of the variation in practice prescribing costs can be explained by differences in practice list size, the proportion of patients aged 65 years and over, the proportion of patients living in ‘deprived areas’ and whether or not the practice qualifies for ‘inducement payments’. The implications of the results for budget setting are discussed. A resource allocation formula based on regression analysis of expenditures can be used to promote horizontal equity in terms of equal budgets for equal need. However, its implications for vertical equity and efficiency are more ambiguous.
BMP7 promotes adipogenic but not osteo‐/chondrogenic differentiation of adult human bone marrow‐derived stem cells in high‐density micro‐mass culture
Authors: Neumann Katja , Endres Michaela , Ringe Jochen , Flath Bernd , Manz Rudi , Häupl Thomas , Sittinger Michael , Kaps Christian 
Published: May 2007

AbstractThe objective of our study was to elucidate the potential of bone morphogenetic protein‐7 (BMP7) to initiate distinct mesenchymal lineage development of human adult mesenchymal stem cells (MSC) in three‐dimensional micro‐mass culture. Expanded MSC were cultured in high‐density micro‐masses under serum‐free conditions that favor chondrogenic differentiation and were stimulated with 50–200 ng/ml BMP7 or 10 ng/ml transforming growth factor‐β3 (TGFβ3) as control. Histological staining of proteoglycan with alcian blue, mineralized matrix according to von Kossa, and lipids with Oil Red O, immunostaining of type II collagen as well as real‐time gene expression analysis of typical chondrogenic, adipogenic, and osteogenic marker genes showed that BMP7 promoted adipogenic differentiation of MSC. Micro‐masses stimulated with BMP7 developed adipocytic cells filled with lipid droplets and showed an enhanced expression of the adipocyte marker genes fatty acid binding protein 4 (FABP4) and the adipose most abundant transcript 1 (apM1). Development along the chondrogenic lineage or stimulation of osteogenic differentiation were not evident upon stimulation with BMP7 in different concentrations. In contrast, TGFβ3 directed MSC to form a cartilaginous matrix that is rich in proteoglycan and type II collagen. Gene expression analysis of typical chondrocyte marker genes like cartilage oligomeric matrix protein (COMP), link protein, aggrecan, and types IIα1 and IXα3 collagen confirmed chondrogenic differentiation of MSC treated with TGFβ3. These results suggest that BMP7 promotes the adipogenic and not the osteogenic or chondrogenic lineage development of human stem cells when assembled three‐dimensionally in micro‐masses. J. Cell. Biochem. 102: 626–637, 2007. © 2007 Wiley‐Liss, Inc.
Expression of key substrate cycle enzymes in rat spermatogenic cells: Fructose 1,6 bisphosphatase and 6 phosphofructose 1‐kinase
Authors: Yáñez Alejandro J. , Bustamante Ximena , Bertinat Romina , Werner Enrique , Rauch Maria Cecilia , Concha Ilona I. , Reyes Juan G. , Slebe Juan C. 
Published: May 2007

AbstractA substrate cycle composed of phosphofructo 1‐kinase I (PFK) and fructose 1,6 bisphosphatase I (FBPase) has been proposed in rat spermatids. This substrate cycle can explain the ability of glucose to induce a decrease in intracellular ATP, a phenomenon that was related to regulation of [Ca2+]i in these cells. In spite of the importance of this metabolic cycle, the expression and activities of the enzymes that compose such cycle have not been systematically studied in spermatogenic cells. Here, we show that PFK and FBPase activities were present in pachytene spermatocytes and round spermatids extracts. Expression of PFK at the mRNA and protein levels showed a relatively similar expression in spermatogenic cells, but a stronger expression in Sertoli cells. Instead, expression of FBPase at the mRNA and protein levels was stronger in round and elongating spermatids as compared to other spermatogenic cells. A similar pattern was observed when evidencing FBPase activity by a NADPH‐nitroblue tetrazolium‐linked cytochemical assay in isolated pachytene spermatocytes and round spermatids. Rat spermatids also showed the ability to convert lactate to fructose‐ and glucose‐6‐P, indicating that both glycolytic and gluconeogenic fluxes are present in these cells. Our results indicate that a coordinated expression of key substrate cycle enzymes, at the level of PFK/FBPase, appear in the last stages of spermatogenic cell differentiation, suggesting that the co‐regulation of these enzymes are required for the ability of these cells to respond to glucose and induce metabolic and Ca2+ signals that can be important for sperm development and function. J. Cell. Physiol. 212:807–816, 2007. © 2007 Wiley‐Liss, Inc.
Regulation of chondrocyte differentiation by the actin cytoskeleton and adhesive interactions
Authors: Woods Anita , Wang Guoyan , Beier Frank 
Published: May 2007

AbstractChondrocyte differentiation is a multi‐step process characterized by successive changes in cell morphology and gene expression. In addition to tight regulation by numerous soluble factors, these processes are controlled by adhesive events. During the early phase of the chondrocyte life cycle, cell–cell adhesion through molecules such as N‐cadherin and neural cell adhesion molecule (N‐CAM) is required for differentiation of mesenchymal precursor cells to chondrocytes. At later stages, for example in growth plate chondrocytes, adhesion signaling from extracellular matrix (ECM) proteins through integrins and other ECM receptors such as the discoidin domain receptor (DDR) 2 (a collagen receptor) and Annexin V is necessary for normal chondrocyte proliferation and hypertrophy. Cell–matrix interactions are also important for chondrogenesis, for example through the activity of CD44, a receptor for Hyaluronan and collagens. The roles of several signaling molecules involved in adhesive signaling, such as integrin‐linked kinase (ILK) and Rho GTPases, during chondrocyte differentiation are beginning to be understood, and the actin cytoskeleton has been identified as a common target of these adhesive pathways. Complete elucidation of the pathways connecting adhesion receptors to downstream effectors and the mechanisms integrating adhesion signaling with growth factor‐ and hormone‐induced pathways is required for a better understanding of physiological and pathological skeletal development. J. Cell. Physiol. 213: 1–8, 2007. © 2007 Wiley‐Liss, Inc.
Low levels of DNA ligases III and IV sufficient for effective NHEJ
Authors: Windhofer Frank , Wu Wenqi , Iliakis George 
Published: May 2007

AbstractCells of higher eukaryotes rejoin double strand breaks (DSBs) in their DNA predominantly by a non‐homologous DNA end joining (NHEJ) pathway that utilizes the products of DNA‐PKcs, Ku, LIG4, XRCC4, XLF/Cernunnos, Artemis as well as DNA polymerase lambda (termed D‐NHEJ). Mutants with defects in these proteins remove a large proportion of DSBs from their genome utilizing an alternative pathway of NHEJ that operates as a backup (B‐NHEJ). While D‐NHEJ relies exclusively on DNA ligase IV, recent work points to DNA ligase III as a component of B‐NHEJ. Here, we use RNA interference (RNAi) to further investigate the activity requirements for DNA ligase III and IV in the pathways of NHEJ. We report that 70–80% knock down of LIG3 expression has no detectable effect on DSB rejoining, either in D‐NHEJ proficient cells, or in cells where D‐NHEJ has been chemically or genetically compromised. Surprisingly, also LIG4 knock down has no effect on repair proficient cells, but inhibits DSB rejoining in a radiosensitive cell line with a hypomorphic LIG4 mutation that severely compromises its activity. The results suggest that complete coverage for D‐NHEJ or B‐NHEJ is afforded by very low ligase levels and demonstrate residual end joining by DNA ligase IV in cells of patients with mutations in LIG4. J. Cell. Physiol. 213: 475–483, 2007. © 2007 Wiley‐Liss, Inc.
Hormonal regulation of IGFBP‐2 proteolysis is attenuated with progression to androgen insensitivity in the LNCaP progression model
Authors: DeGraff David J. , Malik Manisha , Chen Qian , Miyako Kenichi , Rejto Lidia , Aguiar Adam A. , Bancroft Diccon R.E. , Cohen Pinchas , Sikes Robert A. 
Published: May 2007

AbstractThe identification of molecular determinants involved in the promotion of metastasis and development of androgen insensitive prostate cancer (AI‐PCa) is necessary to discriminate aggressive from indolent disease and to identify therapeutic targets for advanced disease. Overexpression of one particular member of the insulin like growth factor (IGF) axis, IGFBP‐2, is implicated in the development of AI‐PCa and other cancers. Using the LNCaP human PCa progression model, we show that the AI and metastatic prostate cancer cell line C4‐2B4 expresses greater amounts of secreted IGFBP‐2 than the androgen sensitive (AS), non‐metastatic LNCaP progenitor cell line. Further, the ability of androgens to decrease extracellular IGFBP‐2 levels is attenuated in the AI and metastatic C4‐2 cell line. The ability of androgen to negatively regulate extracellular IGFBP‐2 levels was blocked by Casodex in a dose‐dependent manner. The mechanism underlying the androgen‐induced downregulation of secreted IGFBP‐2 appears to involve extracellular proteolysis, resulting in the production of IGFBP‐2 fragments lacking the ability to bind IGF‐I and IGF‐II. As C4‐2 cells have an attenuated ability to proteolyze IGFBP‐2 in response to androgen and C4‐2B4 cells express greater amounts of IGFBP‐2, our data implies that the diminished regulation of IGFBP‐2 and loss of associated proteolytic fragments play a role in the increased metastatic behavior of these cells in vivo. Furthermore, our results suggest that either increased levels of intact IGFBP‐2 or decreased levels of IGFBP‐2 proteolytic fragments could serve as a biomarker to monitor for progression to AI‐PCa. J. Cell. Physiol. 213: 261–268, 2007. © 2007 Wiley‐Liss, Inc.
Serous cutaneous glands in the South American horned frog Ceratophrys ornata (Leptodactylformes, Chthonobatrachia, Ceratophrydae): Ultrastructural expression of poison biosynthesis and maturation
Authors: Arifulova Irina , Delfino Giovanni , Dujsebayeva Tatjana , Fedotovskikh Galina , Nosi Daniele , Terreni Alessandro 
Published: May 2007

AbstractSerous cutaneous glands are described in newly metamorphosed and juvenile specimens of the horned frog Ceratophrys ornata using light and transmission electron microscopy. We report patterns of biosynthesis and maturation of the specific product of the gland secretory unit. The syncytial, secretory compartment possesses a complex of endoplasmic reticulum (predominantly smooth endoplasmic reticulum after metamorphosis) and Golgi stacks. The serous product is weak in density and is contained in vesicles involved in repeating merging processes. During this maturation activity, secondary lysosomes are observed, which derive from autophagic processes (crinophagy) involving the secretory materials. Ceratophrys ornata, a species representative of the type genus of the family Ceratophrydae, belongs to the heterogeneous group of anurans that, possibly as the result of convergence, all produce cutaneous poisons consisting of vesicles or faint density granules. J. Morphol., 2007. © 2007 Wiley‐Liss, Inc.
Electrospray tandem mass spectrometry of epipolythiodioxopiperazines
Authors: Wu Zhi‐Jun , Li Guo‐You , Fang Dong‐Mei , Qi Hua‐Yi , Ren Wei‐Jian , Zhang Guo‐Lin 
Published: May 2007

AbstractLow‐energy collision‐induced electrospray ionization tandem mass spectrometry ESI‐CID‐MS/MS (in the positive ion mode) was used for the structural characterization of a series of five representative epioplythiodioxopipreazines: dethiotetra(methylthio)chemotin, chaetocochins A, B and C, and chemotin isolated from the fungus Chaetomium cochliodes. The fragmentation pathways were elucidated by ESI‐IT‐MSn. The elemental compositions of most of the product ions were confirmed by low‐energy ESI‐CID‐QTOF‐MS/MS analyses. The loss of the S2 molecule seems always to be the first when the SS bond is present. The loss of 77 Da corresponding to the loss of the [CH3SCH2O]' radical was diagnostic for chaetocochins A and B, in which the two piperazines rings are linked by an acetal group. It was found that a McLafferty rearrangement plays a significant role in the skeleton fragmentation of theses series of studied complex multicyclic piperazine compounds. This MacLafferty rearrangement affords the product ions at m/z 416 and 400, containing the two piperazine rings belonging to the epipolythiodioxopipreazines. In addition, the pentacyclic rearrangement involving the loss of the SMe· radical seems to occur in the presence of the unfused ring. Finally the product ions at m/z 635 and 591 seem to be the characteristic ions for chaetocochin A. Copyright © 2007 John Wiley & Sons, Ltd.
On the Raman scattering from semiconducting nanowires
Authors: Cao L. , Laim L. , Valenzuela P. D. , Nabet B. , Spanier J. E. 
Published: May 2007

AbstractWe present a short review of recent work on the unusual Raman scattering characteristics in semiconductor nanowires, focusing on the dependence of the intensity, spectral and spatial character of the scattering response on the size, shape and composition of the nanowires. Results of Raman scattering collected from individual Si and nanowires and nanocones indicate that the observed enhancement is dependent on the diameter (d), the excitation wavelength (λlaser) and the incident polarization state. Strong agreement between experimental data and model calculations of scattering from an infinite dielectric cylinder is found. This size dependence is in accordance with other recent findings in which a diameter‐dependent dipolar ‘antenna’ pattern for the scattered intensity and a cross‐sectional shape dependence of the surface optic (SO) phonon dispersions were seen. Further providing evidence of the nanowire shape and size dependence on Raman scattering, these results suggest manipulation of classical electromagnetic scattering signatures, thereby expanding opportunities for engineering the photonic and sensing properties of nanowires. Copyright © 2007 John Wiley & Sons, Ltd.
Rapid identification of purified enteropathogenic Escherichia coli by microchip electrophoresis
Authors: Law Wai Siang , Teng Teng Tay Elaine , Feng Huatao , Yu Lijun , Zhao Jian Hong , Li Sam Fong Yau 
Published: May 2007

AbstractIn this work, the potential of PDMS‐based microchip electrophoresis in the identifications and characterizations of microorganism was evaluated. Enteropathogenic E. coli (EPEC) was selected as the model microorganism. In this study, separation parameters such as applied voltage, concentrations of buffer and buffer modifier, injection voltage, and duration of injection had been investigated and optimized. Determination of EPEC bacteria could be completed within 2 min with good reproducibility. RSDs were less than 0.5 and 5% in migration time and peak area, respectively. Separation efficiency corresponding to plate number of more than 100 000 was achieved. In order to obtain reproducible separations, sample pretreatment was found to be essential. Microchip electrophoresis with LIF detection could potentially revolutionize certain aspects of microbiology involving diagnosis, profiling of pathogens, environmental analysis, and many other areas of study.
Microchip‐based capillary electrophoresis for determination of lactate dehydrogenase isoenzymes
Authors: Zhuang Gui‐Sheng , Liu Jing , Jia Chun‐Ping , Jin Qing‐Hui , Zhao Jian‐Long , Wang Hui‐Min 
Published: May 2007

AbstractThis article describes a novel microchip‐based capillary electrophoresis and on‐column enzymatic reaction analysis protocol for lactate dehydrogenase (LDH) isoenzymes with a home‐made xenon lamp‐induced fluorescence detection system. A microchip integrated with a temperature‐control unit is designed and fabricated for low‐temperature electrophoretic separation of LDH isoenzymes, optimal enzyme reaction temperature control, and product detection. A four‐step operation and temperature control are employed for the determination of LDH activity by on‐chip monitoring of the amount of incubation product of NADH during the fixed incubation period and at a fixed temperature. Experiments on the determination of LDH standard sample and serum LDH isoenzymes from a healthy adult donor are carried out. The results are comparable with those obtained by conventional CE. Shorter analysis times and a more stable and lower background baseline can be achieved. The efficient separation of different LDH forms indicates the potential of microfluidic devices for isoenzyme assay.
Pipetting causes shear stress and elevation of phosphorylated stress‐activated protein kinase/jun kinase in preimplantation embryos
Authors: Xie Y. , Wang F. , Puscheck E.E. , Rappolee D.A. 
Published: May 2007

AbstractShear stress at 1.2 dynes/cm2 induces stress‐activated protein kinase/jun kinase phosphorylation that precedes and causes apoptosis in embryos (Xie et al., 2006b, Biol Reprod). Pipetting embryos is necessary for many protocols, from in vitro fertilization to collecting embryos prior to analyzing gene expression by microarrays. We sought to determine if pipetting upregulates phosphorylated MAPK8/9 (formerly known as stress‐activated protein kinase/jun kinase/SAPK/JNK1, 2). We found that phosphorylated MAPK8/9, a marker of MAPK8/9 activation, is upregulated in a dose‐dependent manner by pipetting. Whereas embryos with the zona pellucida removed were more sensitive to stress‐induced lethality mediated by 1.2 dynes/cm2 shear force, phosphorylated MAPK8/9 was induced at lower numbers of pipet triturations in hatched embryos at E4.5. E4.5 embryos were more sensitive to induction of MAPK8/9 than unhatched embryos at E2.5 or E3.5. E3.5 embryos also showed a pipetting dose‐dependent induction of FOS protein (formerly known as c‐fos), a marker of shear stress in many cell types. Phosphorylated MAPK8/9 measured in ex vivo embryos from E1.5 to E4.5 were expressed at low levels. Embryos that had been pipetted sufficiently to induce phosphorylated MAPK8/9 and FOS had the same number of cells as untreated embryos 24 hr later. This suggests that rapid phosphorylation of MAPK8/9 due to transient shear stress does not mediate long‐term negative biological outcomes. But, it is possible that techniques requiring multiple handling events would induce MAPK8/9 and cause biological outcomes or that other biological outcomes are affected by low amounts of transient shear stress. This study suggests that embryo handling prior to experimental measurement of signal transduction phosphoproteins, proteins and mRNA should be performed with care. Indeed, it is likely that shear stress may cause rapid transient changes in hundreds of proteins and mRNA. Mol. Reprod. Dev. 74: 1287–1294, 2007. © 2007 Wiley‐Liss, Inc.
A heterogeneous arrival and service queueing loss model
Authors: Fond Simson , Ross Sheldon M. 
Published: May 2007

AbstractConsider a single‐server exponential queueing loss system in which the arrival and service rates alternate between the paris (γ1, γ1), and (γ2, μ2), spending an exponential amount of time with rate cμi in (γi, μi), i = 1.2. It is shown that if all arrivals finding the server busy are lost, then the percentage of arrivals lost is a decreasing function of c. This is in line with a general conjecture of Ross to the effect that the “more nonstationary” a Poisson arrival process is, the greater the average customer delay (in infinite capacity models) or the greater the precentage of lost customers (in finite capacity models). We also study the limiting cases when c approaches 0 or infinity.
Return policies for an inventory system with positive and negative demands
Authors: Heyman Daniel P. 
Published: May 2007

AbstractWe consider a single item inventory system with positive and negative stock fluctuations. Items can be purchased from a central stock, n items can be returned for a cost R + rn, and a linear inventory carrying cost is charged. It is shown that for minimizing the asymptotic cost rate when returns are a significant fraction of stock usage, a two‐critical‐number policy (a,b) is optimal, where b is the trigger level for returns and b – a is the return quantity. The values for a and b are found, as well as the operating characteristics of the system. We also consider the optimal return decision to make at time zero and show that it is partially determined by a and b.
The distribution of recoverable inventory items from a repair center when the number of consumption centers is large
Authors: Miller Bruce L. , Modarres‐Yazdi Mohammad 
Published: May 2007

AbstractThis paper considers real‐time decision rules for an inventory system where items are repaired than “used up.” The problem is to decide which user in the system has the greatest need for the newly available inventory items coming out of repair. The main result shows that two published approahes, the Transportation Time Look Ahead policy and METRIC, are optimal when the number of users gets large. A useful byproduct of the proof is a lower bound on the average backorder rate for a repair‐inventory system of any size.
Optimal sampling and the right‐hand side of a linear program: Sensitivity analysis revisited
Authors: Daughety Andrew F. 
Published: May 2007

AbstractThis paper examines right‐hand side sensitivity analysis in linear programming as a problem in optimal sampling. Specifically, the insensitivity point of a solution is defined as the point at which the expected gain from increased accuracy in the prediction of a resource level is equal to the expected cost of procuring the information. The problem is structured using the rudiments of optimal statistical decision theory.
A streamlined simplex approach to the singly constrained transportation problem
Authors: Klingman D. , Russell R. 
Published: May 2007

AbstractA primal simplex procedure is developed to solve transportation problems with an arbitrary additional linear constraint. The approach is a specialization of the Double Reverse Method of Charnes and Cooper. Efficient procedures for pricing‐out the basis, determining representations, and implementing the change of basis are presented. These procedures exploit the pure transportation substructure in such a manner that full advantage may be taken of the computational schemes and list structures used to store and update the basis in codifying the MODI method. Furthermore, the pricing‐out and change‐of‐basis procedures are organized in a manner that permits the calculations for one to be utilized in the other. Computational results are presented which indicate that this method is at least 50 times faster than the state‐of‐the‐art LP code, APEX‐III. Methods for obtaining basic primal “feasible” starts and “good” feasible integer solutions are also presented.