bluuebunny/crossref_metadata_2025_split huggingface dataset:
A generalization of Friedman's rank statistic
Authors: Kroon J. de , Laan P. van der 
Published: April 2008

Abstract  In this paper a very natural generalization of the two‐way analysis of variance rank statistic of Friedman is given. The general distribution‐free test procedure based on this statistic for the effect of J treatments in a random block design can be applied in general two‐way layouts without interactions and with different numbers of the continuous observations per cell provided the design scheme is connected. The asymptotic distribution under the null hypothesis of the test statistic is derived. A comparison with the method of m rankings of Benard and van Elteren is made. The disadvantage of Benard and van Elteren's test procedure is that the number of observations per block does influence the statistic twice, namely firstly by the number itself, as it should, and see ondly by the level of the ranks which will be different in different blocks if the numbers of observations per block are different. The proposed test statistic is not sensitive to differences in the levels of the ranks caused by the different numbers of observations per block. The test is derived from considerhg the Kruskal‐Wallis statistics per block.Finally, the results of simulation experiments are given. The simulation is carried out for three designs and a number of normal location alternatives and gives some information about the power of the suggested test procedure. A comparison is made with Benard and van Elteren's test and with the classical analysis of variance technique. For some simple orthogonal designs the exact null distributions of Benard and van Elteren's test and the proposed test are compared.
CURRENT STATISTICAL ISSUES IN AGRICULTURAL RESEARCH
Authors: CORSTEN L.C.A. 
Published: April 2008

AbstractFour topics, selected from the range of statistical subjects with current relevance for agricultural research are considered. The first is concerned with the need and usefulness of efficient incomplete block designs for any number of treatments, either equireplicate or with different number of replicates. The second one is a presentation of linear prediction procedures for phenomena with spatially random behaviour and its generalization towards kriging. Next, a reparametrization of a general four–parameter family of growth curves is recommended, leading to numerically stable parameter estimation for RICHARDS' functions and additional special cases. Finally, the modelling of factorials with continuous response and of log–linear relationships for frequencies is proposed to be handled on the same footing, with preference for an alternative criteria of model deviance over test critera or Cp–like measures.
ON THE ESTIMATION OF POPULATION MEANS AND RATIOS USING SUPPLEMENTARY INFORMATION
Authors: Upadhyaya L.N. , Singh H.P. , Vos J.W.E. 
Published: April 2008

AbstractIn this paper we discuss the problem of estimating population means and ratios of population means using supplementary information on an auxiliary variable. Two classes of estimators are proposed, depending on two parameters. The bias and mean square error of each of the involved estimators is obtained to the first order of approximation. It is shown that, with a proper choice of the values for the parameters, the estimators are more efficient than the conventional estimators. Numerical examples are provided.
AGREEMENT ON A TWO–POINT SCALE
Authors: Fidler V. , Nagelkerke N.J.D. 
Published: April 2008

AbstractConsider m observers each classifying n objects into one of two disjoint categories. The problem of measuring agreement among m observers is discussed. A new approach, based on a specific parametric model, is recommended. The approach is applied to data on agreement in judging biopsy slides.
The Misspecification of Arma Models
Authors: Pollock D.S.G. 
Published: April 2008

The object of this paper is to assess the effects of fitting a model of the wrong order to a time series which is generated by an autoregressive moving–average process. The method is to examine the spectral density functions which are indicated by the probability limits of the least–squares estimators of the misspecified models. The least–squares estimates are asymptotically equivalent to the maximum–likelihood estimates.The experiments reported in this paper suggest that, if the spectral density function of the data–generating process displays prominent modes, then there is a danger of being seriously misled about the nature of the process whenever one fits a model with too few parameters. It also transpires that, in such cases, the criterion function is liable to have several local minima.Autoregressive moving–average models are being used increasingly in object detection applications where the spectrum of a signal serves to identify the nature of its source. Our results suggest that radical misidentifications can result from the use of incorrectly parametrised models.
A Note on Properties of Iterative Procedures of Asymptotic Inference
Authors: Paardekooper H.C.H. , Steens H.B.A. , van der Hoek G. 
Published: April 2008

This note deals with the article ‘On iterative procedures of asymptotic inference’ by K.O. DZHAPARIDZE (1983), in which an informal discussion is given on performing an unconstrained maximization or solving non–linear equations of statistics by iterative methods with the quadratic termination property. It discusses the theorem that if a maximized function, e.g. the likelihood function, is asymptotically quadratic, then for asymptotically efficient inference finitely many iterations are needed.It is argued here that the theory still applies if certain well specified inexact (hence computationally cheaper) line searches are used in the optimization.
Lichen planus and other cutaneous manifestations in chronic hepatitis C: pre‐ and post‐interferon‐based treatment prevalence vary in a cohort of patients from low hepatitis C virus endemic area
Authors: Maticic M , Poljak M , Lunder T , Rener‐Sitar K , Stojanovic L 
Published: April 2008

AbstractBackground  Several controversies exist regarding the relationship between hepatitis C virus (HCV) infection and some cutaneous manifestations, lichen planus (LP) in particular.Objectives  To determine the prevalence of LP and other cutaneous manifestations in a cohort of patients infected with HCV from low HCV endemic area of Slovenia, to correlate findings with chosen biological variables and to assess the role of interferon (IFN)‐based treatment of HCV infection in cutaneous manifestations.Methods  A total of 171 consecutive HCV‐seropositive patients and 171 HCV‐seronegative age‐ and gender‐matched controls were studied prospectively. Prevalence of cutaneous manifestations, comparison between study patients and controls and correlation of skin findings with demographic, biochemical, virological and liver histologic findings as well as IFN‐based therapy were assessed.Results  Overall presence of LP in HCV‐seropositives was 2.3%; although LP was not found in controls, the difference was not statistically significant (P = 0.123). Significantly higher than in controls was the prevalence of pruritus (31.0%, P < 0.001), dry skin (16.4%, P < 0.001) and hair loss (9.9%, P < 0.001). In IFN‐based treatment naïves, skin findings were more frequent compared with controls, but not significantly, with no correlation to chosen biological variables. Current IFN‐based treatment was significantly connected to pruritus (P < 0.001) and dry skin (P < 0.001). Compared with treatment naïves, in post‐treated patients pruritus (odds ratio, 19.13; 95% confidence interval, 6.85–53.42; P < 0.001), dry skin (odds ratio, 4.21; 95% confidence interval, 1.44–12.31; P < 0.001) and hair loss (P < 0.001) were significantly more common.Conclusions  LP was not significantly related to HCV infection. Prevalence of pruritus, dry skin and hair loss was significantly higher in post‐compared with pre‐treated patients. The role of IFN in post‐treatment persistence of skin manifestations needs to be assessed.
Contact allergy in patients with rosacea: a clinic‐based, prospective epidemiological study
Authors: Jappe U , Schäfer T , Schnuch A , Uter W 
Published: April 2008

AbstractBackground  Rosacea is a relatively common inflammatory skin disease of unknown prevalence. The proportion of contact allergy complicating rosacea and its therapy, respectively, is largely unknown.Objective  To estimate the prevalence of specific contact allergy in rosacea patients and to compare this with the prevalence observed in the general population and in general patch test patients.Patients/methods  In this prospective monocentre study, 78 patients with rosacea were investigated for contact sensitizations via patch testing the standard series, constituents of topical formulations, preservatives, fragrances, topically applied drugs and, if available, patient's own products.Results  Positive reactions occurred to nickel (II) sulphate (12 of 78, 15.4%), fragrance mix I (4 of 77, 5.2%), balsam of Peru (8 of 77, 10.4%; significantly elevated prevalence compared to that observed in the population‐based KORA study), potassium dichromate (4 of 78, 5.1%) and Lyral (3 of 78, 3.8%). Regarding topical antibiotics, only 1 of 78 (1.3%) patients was positive to neomycin sulphate, and none to metronidazole; however, 6 of 75 (8%) patients were positive to gentamicin sulphate, and 4 of 76 (5.3%) patients were positive to framycetin sulphate. No allergic but irritant patch test reactions, instead, were provoked by various patients’ own products as well as by the irritant sodium lauryl sulphate (SLS) even in low concentrations.Conclusion  Despite the limited power of the study, a strikingly high prevalence of contact allergy to gentamicin sulphate was observed, which is probably due to antibiotic treatment of rosacea‐associated eye symptoms. The reactions to the irritant SLS probably mirror the extreme skin sensitivity in rosacea.
Erythropoietin inhibits cytokine production of neonatal and adult leukocytes
Authors: Strunk Tobias , Härtel Christoph , Temming Petra , Matzke Nadja , Zimmer Janna , Schultz Christian 
Published: April 2008

AbstractBackground: Erythropoietin (Epo) was originally defined as a hematopoietic growth factor, but also has potent tissue‐protective properties. The cytokine‐modulating actions of Epo have received scant attention. We hypothesized that Epo significantly influences the in vitro cytokine production in both neonates and adults.Methods: The effects of Epo were investigated using a standardized in vitro whole blood assay. Production of various cytokines was assessed by means of intracellular cytokine detection (IL‐2, ‐6, ‐8, IFN‐γ and TNF‐α) in preterm infants, term neonates and adults. Furthermore, synthesis of IL‐4, ‐5 and ‐10 in adults was investigated via cytometric bead array.Results: Epo significantly inhibits the production of various cytokines in preterm infants, term neonates and adults. In CD3+ lymphocytes, Epo predominantly decreases the number of IL‐2‐positive cells in all age groups. Similarly, in CD14+ cells, Epo significantly diminishes the number of IL‐6‐ and TNF‐α‐producing cells. Furthermore, Epo significantly inhibits the synthesis of IL‐4, IL‐5 and IL‐10 in adults.Conclusion: rhEpo has significant inhibitory potential on the production of various cytokines by leukocytes in preterm and term infants as well as in adults. The described effect likely contributes to the tissue protective properties of Epo.
Risk factors for early sepsis in very low birth weight neonates with respiratory distress syndrome
Authors: Shani Laliv , Weitzman Dahlia , Melamed Rimma , Zmora Ehud , Marks Kyla 
Published: April 2008

AbstractAim: To identify maternal and neonatal factors that increase suspicion of early sepsis in Very Low Birth Weight neonates with respiratory distress syndrome.Methods: The cohort included 282 neonates born at Soroka Medical Centre 1996–2000. Definitions of ‘high’ and ‘low’‐suspicion groups for early sepsis were based on comparison between neonates with early sepsis and the remaining cohort. Univariate analysis and logistic regression were used to compare between groups.Results: The incidence of early sepsis in the cohort was 1.8%, and 94% received antibiotics following delivery. Comparing with the remaining cohort, the five neonates with early sepsis had increased incidence of positive maternal cultures, use of antenatal antibiotics, lower 1 min Apgar scores and tendency to leucopenia. A ‘low‐suspicion’ group comprised 38% of the cohort and did not include any neonates with early sepsis. This group were more frequently treated with antenatal steroids and delivered by Caesarean section compared to the ‘high‐suspicion’ group, but otherwise there were no clinical and laboratory differences.Conclusion: Although the incidence of early sepsis is low almost all neonates received antibiotics. A ‘low‐suspicion’ group was defined and the role of antibiotic treatment in this group needs to be determined.
Pseudohypericin and Hyperforin in Hypericum perforatum from Northern Turkey: Variation among Populations, Plant Parts and Phenological Stages
Authors: Çirak Cüneyt , Radusiene Jolita , Janulis Valdimaras , Ivanauskas Liudas 
Published: April 2008

Abstract
Hypericum perforatum is a perennial medicinal plant known as “St. John's wort” in Western Europe and has been used in the treatment of several diseases for centuries. In the present study, morphologic, phenologic and population variability in pseudohypericin and hyperforin concentrations among H. perforatum populations from Northern Turkey was investigated for the first time. The aerial parts of H. perforatum plants representing a total of 30 individuals were collected at full flowering from 10 sites of Northern Turkey to search the regional variation in the secondary metabolite concentrations. For morphologic and phenologic sampling, plants from one site were gathered in five phenological stages: vegetative, floral budding, full flowering, fresh fruiting and mature fruiting. The plant materials were air‐dried at room temperature and subsequently assayed for chemical concentrations by high performance liquid chromatography. Secondary metabolite concentrations ranged from traces to 2.94 mg/g dry weight (DW) for pseudohypericin and traces –6.29 mg/g DW for hyperforin. The differences in the secondary metabolite concentrations among populations of H. perforatum were found to be significant. The populations varied greatly in hyperforin concentrations, whereas they produced a similar amount of pseudohypericin. Concentrations of both secondary metabolites in all tissues increased with advancing of plant development and higher accumulation levels were reached at flowering. Among different tissues, full opened flowers were found to be superior to stems, leaves and the other reproductive parts with regard to pseudohypericin and hyperforin accumulations. The present findings might be useful to optimize the processing methodology of wild‐harvested plant material and obtain increased concentrations of these secondary metabolites.
Angiotensin II and epidermal growth factor receptor cross‐talk mediated by a disintegrin and metalloprotease accelerates tumor cell proliferation of hepatocellular carcinoma cell lines
Authors: Itabashi Hidenori , Maesawa Chihaya , Oikawa Hiroki , Kotani Koji , Sakurai Eiichi , Kato Kuniyuki , Komatsu Hideaki , Nitta Hiroyuki , Kawamura Hidenobu , Wakabayashi Go , Masuda Tomoyuki 
Published: April 2008

Aim:  The cross‐talk pathway between angiotensin II (AngII) and the epidermal growth factor receptor (EGFR) mediated by epidermal growth factor (EGF)‐like ligands cleaved by a disintegrin and metalloprotease (ADAM) has been elucidated in several cell types. Even though the liver is a representative angiotensinogen‐producing organ, such cross‐talk has never been elucidated in hepatocellular carcinomas (HCCs). We investigated whether AngII exerted a mitogenic effect on HCC cell lines through the AngII–EGFR cross‐talk pathway.Methods:  We determined the expression and/or phosphorylation status of AngII receptor type 1 (AGTR1), ADAM9, ADAM17, ERK1/2, STAT3, AKT and EGFR in five HCC cell lines using Western blotting. Proliferation and invasion activities were measured by ATP and Matrigel invasion assays, respectively.Results:  AGTR1 was expressed ubiquitously in HCC cell lines. EGFR expression in HepG2 was relatively weaker than that in the remaining HCC cell lines. The phosphorylation status of EGFR, ERK1/2, STAT3 and AKT was upregulated by AngII treatment in two EGFR‐overexpressing cell lines (Huh7 and PLC/PRF/5), but not in HepG2 (showing weak EGFR expression). AngII stimulation significantly accelerated proliferation and invasion activities in Huh7 and PLC/PRF/5, and was inhibited by pretreatment with an ADAM inhibitor. A selective AGTR1 blocker significantly repressed proliferation activity in both cell lines, but did not significantly repress the invasion activity. Both chemical agents and neutralizing antibodies against ADAMs (ADAM9 and ADAM17) and EGF‐like ligands suppressed EGFR transactivation and/or subsequent phosphorylation of ERK1/2, STAT3 and AKT.Conclusion:  These results suggest that AngII–EGFR cross‐talk signaling mediated by ADAMs is involved in the proliferation and invasion activities of several HCC cell lines.
Microencapsule technique protects hepatocytes from cryoinjury
Authors: Kusano Tomokazu , Aoki Takeshi , Yasuda Daisuke , Matsumoto Shuichiro , Jin Zhenghao , Nishino Nobukazu , Hayashi Ken , Odaira Masanori , Yamada Kousuke , Koizumi Tomotake , Izumida Yoshihiko , Mitamura Keitaro , Enami Yuta , Niiya Takashi , Murai Noriyuki , Kato Hirohisa , Shimizu Yoshinori , Kou Keitatsu , Furukawa Yoshinori , Matsusita Michiaki , Todo Satoru , Shioda Seiji , Kusano Mitsuo 
Published: April 2008

Aim:  Hepatocyte transplantation is a potential alternative to whole organ liver transplantation. To realize this procedure, a hepatocyte bank system capable of supplying large numbers of hepatocytes must be established. We previously reported an easy method for cryopreserving hepatocytes using a microencapsulation technique. Here, we investigated how cryoinjury to microencapsulated hepatocytes could be avoided during cryopreservation.Methods:  Hepatocytes from Sprague–Dawley rats were harvested in situ using a two‐step ethylenediaminetetraacetic acid (EDTA)/collagenase digestion protocol. The cells were microencapsulated using alginate‐poly L‐lysine. The microencapsulated hepatocytes were put into vials and immediately immersed in liquid nitrogen. The growth of ice crystals in the vials containing the microencapsulated hepatocytes was observed using cryomicroscopy. The microencapsulated hepatocytes were sectioned for ultrastructural examination to investigate their intracellular conditions. Finally, total RNA was isolated from the cryopreserved microencapsulated hepatocytes and analyzed for hepatocyte nuclear factor (HNF) using reverse transcriptase polymerase chain reaction (RT–PCR) analysis.Results:  Cryomicroscopy showed that the alginate microencapsulation technique protected the hepatocytes from physical damage caused by the growth of extracellular ice crystals. Ultrastructural examination revealed that the intracellular environment of the microencapsulated hepatocytes was maintained. The RT–PCR analysis additionally suggested that the alginate gel also maintained the HNF level.Conclusion:  Our microencapsulation technique protects hepatocytes from cryoinjury. This novel technique could be utilized by hepatocyte banks.
Occult hepatitis B virus infection as a risk factor for hepatocellular carcinoma in patients with chronic hepatitis C in whom viral eradication fails
Authors: Miura Yukiko , Shibuya Akitaka , Adachi Shigeru , Takeuchi Atsuko , Tsuchihashi Takeshi , Nakazawa Takahide , Saigenji Katsunori 
Published: April 2008

Aim:  Recent studies have suggested that an occult hepatitis B virus (HBV) infection negative for HBsAg but positive for HBV‐DNA contributes to hepatocellular carcinoma (HCC) development in patients with chronic hepatitis C. Some follow‐up studies have suggested the clinical importance of occult HBV infections in HCC development even after interferon (IFN) therapy, but a recent study denies the significance of the impact of occult HBV infection. Focusing on HCC development in patients in whom hepatitis C virus (HCV) eradication by interferon (IFN) therapy had failed, we conducted this study in order to assess the impact of occult HBV infections on HCC development in these patients.Methods:  We enrolled 141 patients with chronic hepatitis C (histological stage F2 or F3) who were seropositive for HCV‐RNA even after IFN therapy. Serum HBV‐DNA was assayed using the real‐time polymerase chain reaction. During follow‐up, ultrasonography and/or computed tomography (CT) were performed at least every 6 months to monitor HCC development.Results:  The cumulative incidence rates of HCC were 8.9%, 25.7% and 53.7% at 5 years, 10 years and 15 years, respectively, after IFN therapy. Multivariate analysis indicated that low platelet counts (<12 × 104/mm3), occult HBV infection, high ALT levels (≥80 IU/L) after IFN therapy and the staging of liver fibrosis were important independent factors affecting the appearance of HCC.Conclusions:  Occult HBV was a risk factor for HCC development in patients with chronic hepatitis C in whom HCV eradication had failed. Therefore, patients with chronic hepatitis C with occult HBV should be monitored carefully for HCC after IFN therapy.
Technology Options for Gas Turbine Power Generation With Reduced CO2 Emission
Authors: Griffin Timothy , Bücker Dominikus , Pfeffer Allen 
Published: April 2008

AbstractALSTOM Power R&D laboratories run various programs aimed at finding options that reduce or avoid CO2 emissions through the following: (a) high efficiency power generation equipment to utilize fossil fuels with the lowest possible emissions, and (b) technologies to remove and sequester CO2 created in power plants in an environmentally and economically favorable manner. In this paper, an overview of ongoing CO2 mitigation activities for gas turbine power generation is addressed. Energy efficiency improvements for both new and existing fossil fuel power plants are briefly reviewed. Customer requirements for future power plants with reduced CO2 emissions are discussed. Novel power generation cycles with exhaust gas recirculation for enhanced CO2 removal are introduced and evaluated. Conclusions are drawn regarding their efficiency, energy consumption, and technical feasibility.