bluuebunny/crossref_metadata_2025 huggingface dataset:
SORT OF IN NEW ZEALAND WOMEN'S AND MEN'S SPEECH
Authors: Holmes Janet
Published: November 2008

Sort of is a syntactically flexible pragmatic particle serving a variety of functions in conversation. At a general level sort of functions as a device facilitating the smooth flow of the discourse, providing the speaker with verbal planning time. At a more specific level it serves both as an imprecision or approximation signal (epistemic modal meaning) and as an informality and solidarity marker (affective meaning).

Differences in the distribution of sort of in different corpuses relate most obviously to the context and type of discourse in which participants are engaged. There were few differences between New Zealand women's and men's speech in the total proportions of sort of used, though in semi‐formal contexts it was addressed more often to women than to men.
KABARDIAN DISEMVOWELLED, AGAIN
Authors: Anderson John
Published: November 2008

Kuipers (1960) proposed that Kabardian is contrastively vowel‐less, a hypothesis that has occasioned much controversy ever since, problematical as it is for suggested principles governing phonological systems. This proposal is reconsidered within the context of the suggestions concerning phonological notation put forward within Dependency Phonology. In terms of a framework which recognises that certain segments may be contrastively unspecified and that much else of phonological structure is non‐contrastive, it is concluded that Kuipers' hypothesis has some plausibility; and a formulation of the generalisations governing the distribution and character of vowel variants in Kabardian is offered, on the basis of the contrastive absence of vowels.
THE INFIECTIONAL PROPERTIES OF SCANDINAVIAN ADJECTIVES*
Authors: Kester Ellen‐Petra
Published: November 2008

Abstract. This paper is about the morphology of Scandinavian adjectives in definite DPs, traditionally known as the weak paradigm of adjectival inflection. It will be argued that these morphological endings, referred to as dummy affixes, are licensed by the definiteness features in the head of DP. Dummy affixes share certain morphological and syntactic properties with anaphoric clitics in Romance languages: both are poor in phi‐features and both are submitted to strict locality conditions. The proposed analysis of dummy affixation can be extended to account for the structure of DP and the double definiteness phenomenon in languages like Norwegian and Swedish.
WHAT ARE VOWELS MADE OF? THE ‘NO‐RULE’ APPROACH AND PARTICLE PHONOLOGY*
Authors: de Carvalho Joaquim Brandão
Published: November 2008

Abstract. According to current unarist theories of vowel systems, minimal components (like A, I, U, etc.) are structured in relation to one another either in terms of dependency (or government) relationships (dependency and government phonologies), or by their relative weight (particle phonology). No attempt has been made in order to evaluate both formalisms, which are sometimes used simultaneously to represent vowel height. The present paper claims that both government and weight are required in the representation of vowel structure, insofar as each notion is specifically motivated. It is argued that government and weight express respectively the ‘functional’ and the ‘structural’ aspects of vowel systems. The main point is that such a distinction allows for a strict ‘principles and parameters’ approach to vowel structure and processes. This theory, which is formally an autosegmental development of particle phonology, provides, as is fully shown by Portuguese data, a unitary and natural account of complex processes by substituting one universal principle for several descriptive rules.
THE ROLE OF TRIGGERS IN THE EXTENDED SPLIT INFL HYPOTHESIS: UNLEARNABLE PARAMETER SETTINGS*
Authors: Watanabe Akira
Published: November 2008

Abstract. This paper argues that the Extended Split INFL hypothesis of Chomsky (1991) opens up a new perspective on the nature of triggers of verb raising. Raising to Agr‐s is triggered by rich agreement while the trigger of raising to Tns is word order. This explains (1) persistence of verb‐raising in Early Modern English even after considerable erosion of agreement, and (2) loss of verb‐raising after the loss of agreement in Mainland Scandinavian. Verb‐raising in English at the relevant stage was to Tns. In Mainland Scandinavian, degree‐0 learnability of Lightfoot (1991) in combination with V2, has as a consequence that loss of agreement led to loss of verb‐raising.
The effect of enemy‐release and climate conditions on invasive birds: a regional test using the rose‐ringed parakeet (Psittacula krameri) as a case study
Authors: Shwartz Assaf , Strubbe Diederik , Butler Chris John , Matthysen Erik , Kark Salit
Published: November 2008

Aim Some invasive species succeed particularly well and manage to establish populations across a wide variety of regions and climatic conditions. Understanding how biotic and environmental factors facilitate their invasion success remains a challenge. Here, we assess the role of two major hypotheses explaining invasion success: (1) enemy‐release, which argues that invasive species are freed from their native predators and parasites in the new areas; and (2) climate‐matching, which argues that the climatic similarity between the exotic and native range determines the success of invasive populations.

Location India, Israel and the UK.

Methods We studied the reproductive success of one of the most successful avian invaders, the rose‐ringed parakeet (Psittacula krameri), in its native range (India) and in two introduced regions, varying in their climate conditions (Israel and the UK). We combined literature and field data to evaluate the role of predation pressure and climatic conditions in explaining the differences in reproductive success between the three regions.

Results We found significant differences in reproductive success between regions. In accordance with the enemy‐release hypothesis, we discovered that while predation was the main factor responsible for the reduction of fecundity in India, it did not significantly affect the fecundities of parakeet populations in the two introduced regions. In accordance with the climate‐matching hypothesis, we found that in the colder temperate UK, egg infertility was high, resulting in lower fecundities. Populations in both the warmer Mediterranean climate of Israel and in the native Indian range had significantly lower egg infertility and higher fecundities than the UK populations.

Main conclusions Our findings support both the enemy‐release and the climate‐matching hypotheses. While release from predators facilitates the reproductive success and therefore the invasiveness of parakeets in both the UK and in Israel, colder climate impedes reproduction and therefore the spread of parakeets in the UK.
Prospective study of complier individuals under periodontal maintenance therapy: analysis of clinical periodontal parameters, risk predictors and the progression of periodontitis
Authors: Lorentz Telma Campos Medeiros , Miranda Cota Luís Otávio , Cortelli José Roberto , Vargas Andréa Maria Duarte , Costa Fernando Oliveira
Published: November 2008

Aim: This prospective study aimed to evaluate the progression of periodontitis and the influence of risk variables among individuals attending a programme of periodontal maintenance treatment in an academic environment.

Material and Methods: A total of 150 individuals diagnosed with chronic moderate‐advanced periodontitis, and who had finished active periodontal treatment, were incorporated into the periodontal maintenance therapy. Social, demographic and biological variables of interest from subjects were collected at quarterly recalls, over a 12‐month period. The effect of variables of interest and confounding on the periodontal status and progression of periodontitis was tested by univariate and multivariate logistic analysis.

Results: A total of 130 subjects (86.7%) showed stable periodontal status, whereas 20 subjects (13.3%) presented periodontitis progression. Twenty‐eight subjects (18.66%) presented tooth loss that resulted in a total of 47 lost teeth (1.38%). Diabetes was not found to be associated with periodontitis progression (p=0.67). Smoking was significantly associated with a greater progression of periodontitis (OR=2.7, 95% CI 1.01–7.22).

Conclusions: Periodontal maintenance programmes in academic environment can stabilize the periodontal condition obtained after active periodontal therapy as well as control the action of risk variables for the progression of periodontitis.
Food Deprivation Promotes Oxidative Imbalance in Rat Brain
Authors: Santos R.X. , Cardoso S. , Silva S. , Correia S. , Carvalho C. , Crisóstomo J. , Rodrigues L. , Amaral C. , Louro T. , Matafome P. , Santos M.S. , Proença T. , Duarte A.I. , Seiça R. , Moreira P.I.
Published: November 2008

ABSTRACT:  The present study was aimed to evaluate the effect of food deprivation in brain oxidative status of Wistar and Goto‐Kakizaki (GK) rats. For this purpose, we evaluated several oxidative stress parameters: lipid peroxidation (thiobarbituric acid reactive substances [TBARS]) and protein oxidation markers, hydrogen peroxide (H2O2) levels, nonenzymatic (reduced [GSH] and oxidized glutathione [GSSG] and vitamin E) and enzymatic (glutathione peroxidase [GPx], glutathione reductase [GRed], and manganese superoxide dismutase [MnSOD]) antioxidant defenses. Four‐mo‐old Wistar and GK rats were divided into 2 groups. One group of each rat strain was maintained under normal diet and the other groups were maintained under 50% food deprivation during 2 mo. GK rats under normal diet presented lower levels of vitamin E and higher GRed activity and GSH/GSSG ratio when compared with Wistar control rats. In Wistar rats, food deprivation induced a significant decrease in vitamin E levels and a significant increase in GPx activity, H2O2 production, and TBARS formation in the presence of the prooxidant pair ADP/Fe2+. However, GK rats under food deprivation presented a significant decrease in vitamin E levels and GRed activity and a significant increase in H2O2 production when compared with GK under normal diet. In summary, our results indicate that food deprivation affects brain oxidative status, which could predispose brain cells to degeneration and death.
Discoloration Characteristics of 3 Major Muscles From Cattle During Cold Storage
Authors: Jeong J.Y. , Hur S.J. , Yang H.S. , Moon S.H. , Hwang Y.H. , Park G.B. , Joo S.T.
Published: November 2008

ABSTRACT:  Discoloration characteristics of 3 major muscles (LD, Longissimus dorsi; PM, Psoas major; SM, Semimemebranosus) from Korean native cattle (Hanwoo) were monitored during 7 d of cold storage at 4 °C. The muscles were obtained from 12 Hanwoo carcasses at 24 h postmortem. Meat color (CIE L*, a*, b*), myoglobin (Mb) concentration, chemical form, metmyoglobin (MetMb) reducing ability (MRA), mitochondria concentration, and thiobarbituric acid reactive substance (TBARS) were measured at 1, 3, 5, and 7 d of storage. Although there were no significant differences in CIE a* and b*‐values between the 3 muscles at day 1, the values of PM muscle were significantly (P < 0.05) lower than those of LD and SM muscles at day 5 and 7. PM muscle showed a rapid decrease in the oxymyoglobin (OxyMb) and an increase in MetMb, which resulted in a significantly (P < 0.05) higher percentage of MetMb in PM muscle compared to LD and SM muscles. Also, the Mb and mitochondria concentration of PM muscle was significantly (P < 0.05) higher than those of LD and SM muscles. However, there were no significant differences in MRA, pH, or TBARS between the 3 muscles during 7 d of cold storage. It was concluded that rapid discoloration (that is, MetMb accumulation) in PM muscle of Hanwoo could be due to its higher contents of Mb and mitochondria.
Rethinking the South China Sea Issue: A Perspective of Sino‐U.S. Relations
Authors: Wang Yiwei
Published: November 2008

Three essential factors of international politics underlie current controversies regarding the South China Sea: sovereignty, resources and strategy. Before the 1980's, the United States maintained a completely “neutral position” towards this issue for a number of historical reasons. However, when the 1982 UNCLOS III entered into force in 1994, the South China Sea joined Taiwan and the tensions on the Korean Peninsula as one of three potential flashpoints in the Asia‐Pacific region. Since 1994, American foreign policy regarding the South China Sea underwent three stages of development: prevention–deterrence–practice. This article analyzes these changes by focusing on the development of America's Asia‐Pacific security strategy, especially one of its main outcomes: the development of the Sino‐U.S. relationship.

From balance of power and geopolitical theories, in the long run, the South China Sea issue may become a global fulcrum between the U.S. and China, which probably will become a global power in the future. Even as a regional power today, it is well known that the Taiwan issue has led to conflict and competition with the U.S. for more than half a century. To avoid falling into the same old trap again as with the Taiwan issue in the past, we must prepare for a rainy day in solving the South China Sea issue, in essence, to find a balance between China's position, which represents a newcomer's demands, and international maritime law, which represents the vested interests of the international system. We need a long‐term perspective to deal with the Sino‐U.S relationship.
The nucleolar cycle in the myxomycete Physarum polycephalum. II. Mode of formation of the nucleolus
Authors: Lafontaine J. G. , Cadrin M. , Lord A.
Published: November 2008

The previous ultracytochemical investigation has revealed that the numerous nucleolar remnants observed during the mitotic stages in Physarum polycephalum possess the same characteristics as chromatin and originate from the fibrillar zones of the mature nucleolus. In the present study these nucleolar minichromosomes are shown to be incorporated as well-defined structural elements within the two daughter nuclei. At very early interphase these minichromosomes are first scattered throughout the nuclear cavity, but within a few minutes they aggregate to form several highly irregular masses corresponding to prenucleolar bodies. By the time these latter bodies fuse into typical horseshoelike nucleoli, pervading granular material starts accumulating in more noticeable amounts. Following labeling for 10 min with uridine radioautographic grains are already detected in very early interphase nuclei over dense regions undoubtedly corresponding to the minichromosomes. Incorporation of this RNA precursor increases as the minichromosomes fuse into prenucleolar bodies. By the time large nucleoplasmic zones have formed, radio-autographic grains are present in still larger quantity over the irregularly shaped nucleolus as well as over diffuse chromatin thoughout the nuclear cavity. Such early RNA synthesis is interpreted to indicate that the early stages of nucleolar formation do not merely involve fusion of the preexisting minichromosomes but also imply synthesis of new material.
Time of appearance of some plant biocharacters during Siluro-Devonian time
Authors: Banks Harlan P.
Published: November 2008

The first occurrence in the fossil record of selected biocharacters of the vascular land plants is recorded. The successive appearance of these biocharacters documents the evolution of progressively more complex morphology and anatomy during Silurian and Devonian times.
Population genetic structure of North American burbot (Lota lota maculosa) across the Nearctic and at its contact zone with Eurasian burbot (Lota lota lota)
Authors: Elmer Kathryn R. , Van Houdt Jeroen K.J. , Meyer Axel , Volckaert Filip A.M.
Published: November 2008

The burbot, Lota lota (Teleostei: Gadidae), has a holarctic distribution, with one subspecies ( Lota lota lota ) living in the lakes and rivers of the Palaearctic and northwestern North America and the other ( Lota lota maculosa ) living in the Nearctic (except the northwest). We analysed nine microsatellite loci and the mitochondrial DNA control region of 350 burbot sampled across North America to develop a continent-wide understanding of population differentiation following postglacial recolonization. Using mitochondrial DNA, we identify three subclades of L. l. maculosa: one is widespread, one is moderately well distributed, and the third is restricted to the southwest. Lota l. lota is restricted to Yukon and Alaska. Microsatellite loci show moderate levels of genetic diversity and high population differentiation throughout North America (Rst ≤ 0.9). Lota l. maculosa and L. l. lota mtDNA lineages only co-occur appreciably in Great Slave Lake. An individual-based Bayesian approach to detect genotypic admixture indicates that very few of all individuals show signs of admixture between subspecies, and those individuals are restricted to Great Slave Lake and Lake Laberge.
Advanced treatment of landfill leachate from a sequencing batch reactor (SBR) by electrochemical oxidation process
Authors: Chu Yanyang , Zhang Qinhui , Xu Dimin
Published: November 2008

Biologically stabilized landfill leachate usually requires further removal of organic substances and ammonia nitrogen (NH3-N) before final discharge. In this paper, the advanced treatment of landfill leachate pretreated by sequencing batch reactor (SBR) via electrochemical oxidation was carried out in an electrochemical compartment reactor with oxide-coated titanium anode (Ti/TiO2-IrO2). The effect of voltage, chlorine content, initial pH value, and ferrous sulfate (FeSO4) on the removal efficiency of contaminants was investigated systematically. The removal efficiency of organic pollutants and ammonia nitrogen (NH3-N) increased with the increase of voltage, chlorine content and the addition of ferrous iron. The initial pH value has a different effect on the removal of COD and NH3-N. Compared with the traditional electrochemical oxidation, the process with Fe(II/III) is more efficient with low power consumption, and the removal efficiency of organic pollutant is slightly lower when Fe(II) is used. A lower power consumption of 16.6 kWh·(kg COD)–1 indicated the electrochemical oxidation with Fe(II) was a promising alternative for the advanced treatment of leachate.
Soil type effects on petroleum contamination characterization using ultraviolet induced fluorescence excitation-emission matrices (EEMs) and parallel factor analysis (PARAFAC)
Authors: Alostaz Moh'd , Biggar Kevin , Donahue Robert , Hall Gregory
Published: November 2008

The ultraviolet induced fluorescence signatures of various petroleum products were evaluated in different soils to examine the impact of soil type, grain size, porosity, and mineralogy. The different soil matrices induced changes to the spectral features of petroleum hydrocarbon fluorescence excitation-emission matrices (EEMs). Once the effect of the soil matrix was characterized, fluorescence EEMs were analyzed using parallel factor analysis (PARAFAC) and soft independent method of class analogy (SIMCA) to identify the petroleum products and their underlying aromatic hydrocarbon components. For quantitative analysis, total fluorescence values obtained from fluorescence EEMs of analyzed petroleum products were used to estimate their concentrations in different soil matrices. Results indicated that this approach provides identifying fingerprinting and reasonable estimate of concentrations for a number of petroleum products in different soils matrices.
Protein fouling of ultrafiltration membranes — investigation of several factors relevant for tertiary wastewater treatment
Authors: Haberkamp Jens , Ernst Mathias , Makdissy Gladys , Huck Peter M. , Jekel Martin
Published: November 2008

The fouling of two different ultrafiltration membranes by solutions of three globular proteins with different molecular weights and isoelectric points was investigated at low concentrations relevant to secondary effluents (10 mg·L–1). The results reveal the increased fouling potential of macromolecules being small enough to enter the membrane pores due to the resulting blockage and (or) constriction of the pores, compared to a moderate increase of the filtration resistance due to gel layer formation by larger compounds. Differences between the applied membranes in terms of fouling behaviour, protein retention, as well as attachment of macromolecules to membrane surface and pore walls demonstrate the impact of pore size distribution, zeta potential, surface roughness, and hydrophobicity of the membranes on the fouling mechanism. Comparative ultrafiltration experiments using two different pumps indicate the influence of type and dimensioning of the pumping system on membrane fouling due to structural changes of solutes by pump-induced shear forces.
Effects of finite-size joints on the deformability of jointed rock at the two-dimensional level
Authors: Kulatilake Pinnaduwa H.S.W. , Ucpirti Hasan , Stephansson Ove
Published: November 2008

A numerical decomposition technique, which has resulted from a linking between joint-geometry modeling and generation schemes, and a distinct element code (UDEC), is used to study the effect of joint-geometry parameters of finite-size joints on the deformability properties of jointed rock at the two-dimensional (2D) level. The influence of joint-geometry parameters such as joint density, ratio of joint size to block size, and joint orientation on the deformability of jointed rock is shown. Relations are established between deformability properties of jointed rock and fracture-tensor parameters. An incrementally linear elastic, anisotropic constitutive model is developed to represent the prefailure mechanical behaviour of jointed rock at the 2D level. This constitutive model has captured the anisotropic, scale-dependent behaviour of jointed rock. In this model, the effect of the joint-geometry network in the rock mass is incorporated in terms of fracture-tensor components. Some insight is given related to estimation of representative elementary volumes for deformability properties of jointed rock. Key words : rock masses, deformability, distinct element method, fracture tensor, anisotropy, scale effects.
Evaluation of sulphide oxidation rates: a laboratory study comparing oxygen fluxes and rates of oxidation product release
Authors: Elberling B. , Nicholson R.V. , Reardon E.J. , Tibble R
Published: November 2008

A series of column experiments were conducted to evaluate three methods to determine sulphide oxidation rates in mine tailings. Measurements were made of (i) the flux of oxygen across the surface of the tailings, (ii) the oxygen consumption rates at the tailings surface, and (iii) the total sulphate produced in the pore water over time. Two columns were prepared with a mixture of quartz sand and pyrrhotite and overlain with varying thicknesses and grain sizes of a nonreactive layer. The impact of nonreactive layers with varying water-table depths on the overall oxidation rate was also evaluated. Modelling was applied to verify the importance of diffusion and kinetic control of the different column configurations. The results indicate that the overall rate of oxidation is reduced when fine-grain layers are applied. This is due to the high water saturation conditions generated by the fine material regardless of the depth to the water table. The consistency and precision of the methods used to measure relative oxidation rates were noted and a new practical field mapping tool is recommended. The new method provides rapid measurements of relative oxidation rates that can be applied to existing tailings rehabilitation with soil-type covers to show spatial and temporal trends. Key words : sulphide oxidation, tailings, laboratory experiment, oxidation rate methods, water saturation, cover materials.
Dusky dolphin (Lagenorhynchus obscurus) subgroup distribution: are shallow waters a refuge for nursery groups?
Authors: Weir J. S. , Duprey N. M.T. , Würsig B.
Published: November 2008

Mammalian young are especially vulnerable to harm because of their small size, poorly developed survival skills, and strong dependence on maternal care. Tactics for rearing young, including avoiding harm, vary largely by environment type. Off Kaikoura, New Zealand, mother–calf pairs of dusky dolphins ( Lagenorhynchus obscurus (Gray, 1828)) are often found in small groups with other mother–calf pairs, with calves of roughly the same age. These groups, termed “nursery groups”, may distance vulnerable calves from hazards associated with males seeking mating opportunities, predation by sharks and killer whales ( Orcinus orca (L., 1758)), and boat traffic. We conducted systematic boat-based surveys to determine the relative distribution of dusky dolphin group types, predators, and boats in the area. Nursery groups were encountered in shallow waters (≤20 m) significantly more often than in deeper waters (p < 0.001). Boats were found more in shallow water, while predators were almost exclusively encountered in deeper water. Other dusky dolphin group types did not show a preference for deep or shallow waters. Potential harassment from males and the presence of boats were both significant predictors of the depth category in which a group was found (p < 0.03). We recommend that managers focus efforts on protecting this vulnerable subgroup of the dusky dolphin population by protecting their preferred nearshore shallow habitat and by reducing recreational boating and fishing in these areas.
FLUCTUATIONS IN INELASTIC TUNNELING OF ELECTRONS THROUGH SERIALLY COUPLED DOUBLE QUANTUM DOTS
Authors: XU QINGQIANG , XIONG SHI-JIE
Published: November 2008

We investigate the inelastic transport properties of quantum dots connected to two leads, based on the combination of a recently developed nonperturbative technique and full counting statistics involving an approximate mapping of a many-body electron–phonon system onto a multichannel scattering system. The full counting statistics is adopted in the calculations of the inelastic transport processes of electrons where the electron–phonon interactions, which are the main source of the inelasticity, are taken into account. For serially coupled double quantum dots, we find that (i) both the current and the noise are suppressed when electron–phonon interaction switches on, and (ii) skewness becomes negative in a certain parameter regime, which is absent in the case without electron–phonon interactions.
STABILITY BOUNDARY AND DURATION TIME OF SYNCHRONIZATION FOR COUPLED CHAOTIC MATHIEU–DUFFING OSCILLATORS
Authors: SHEN JIANHE , CAI JIANPING , CHEN SHUHUI , LIN KECHANG
Published: November 2008

The stability boundaries and behaviors of the duration time of synchronization for chaotic Mathieu–Duffing oscillators are investigated. Based on the unidirectional or bidirectional linear state error feedback coupled scheme, the error system is derived. After replacing the chaotic orbit by a regular orbit containing multi-harmonics, we analyze the asymptotic stability of the error system, which leads to a Hill equation. According to Floquet theory and the properties of the Hill equation, the evolution of the discriminant of the Hill equation with respect to the coupling strength is traced to determine the stability boundaries between the synchronization and desynchronization domains. Thus, the critical values of coupling strength are obtained. These critical values are in good agreement with those from numerical simulations. The behaviors of the synchronization time are numerically investigated in the synchronization domain. It is found that the synchronization time reaches an asymptotic minimal value when the oscillators are unidirectionally or bidirectionally coupled, and the two asymptotic minimal values are almost the same. It is also noted that the slowing down behavior of the synchronization time can occur inside the synchronization domain when the coupling is bidirectional.
ANTIOXIDANT ACTIVITY OF SOME TYPES OF WHITE WINES AND JUICES INVESTIGATED BY EPR SPECTROSCOPY
Authors: PETRISOR DINA , DAMIAN GRIGORE , SIMON SIMION , HOSU ANAMARIA , MICLAUS VASILE
Published: November 2008

Two types of white wines with different places of provenience, and a few types of commercial and natural juices were chosen for preliminary studies of their antioxidant characteristics by using Electron Paramagnetic Resonance (EPR) spectroscopy. Antioxidant capacity of these samples was assessed using stable free radicals such as nitroxide radical Tempol (2,2,6,6-tetramethyl-4-hydroxypiperidine-oxyl), as a paramagnetic agent. The inhibition by antioxidants of the absorbance of the paramagnetic species was found to decrease in time with different rates, and was correlated to the antioxidant activity of the studied samples. The obtained results permit us to make a brief evaluation of the main antioxidative characteristics of the studied wines and juices samples.
EFFECT OF GAMMA IRRADIATION ON YBa2Cu3O7-δ HIGH TEMPERATURE SUPERCONDUCTORS
Authors: SIDDIQI SAADAT A. , SIDDIQUI RABIA , ALI SALAMAT
Published: November 2008

Samples of YBa 2 Cu 3 O 7-δ superconducting ceramic were prepared and characterized by resistivity measurements using the four probe method and structural analysis using X-ray diffraction (XRD). XRD-patterns show the presence of orthorhombic Y -123 phase with a small fraction of secondary phase, YBa 2 Cu 3 O 5. Samples were irradiated with gamma (γ) rays using Co 60 source with five successive doses of 2.5 Mrad. A monotonic increase in the Tc0 value was observed for radiation dosage up to 10 Mrad. When exposed to even higher γ-doses, the Tc0 value leveled off at a saturation value or decreased. XRD-analysis shows slightly changed values of the lattice constants and a mild shift of diffraction peaks towards a lower 2θ value. These observations indicate structural changes in YBa 2 Cu 3 O 7-δ induced upon gamma irradiation. The present work describes our experimental findings and attempts to offer a theoretical explanation for the effects observed.
Susceptibility to Hyperglycemia in Patients with Chronic Kidney Disease
Authors: Shehab-Eldin Walid , Zaki Ali , Gazareen Sanaa , Shoker Ahmed
Published: November 2008

Background: Patients with chronic kidney disease (CKD) are susceptible to hyperglycemia. Aim: To study the prevalence of pre-diabetes in CKD patients and determine the contribution of insulin resistance (IR) versus β-cell dysfunction in patients with CKD. Methods: 45 consecutive nondiabetic CKD patients and 40 healthy subjects were included. Patients were divided into a normoglycemic (NG) and a pre-diabetic (PDM) group. IR was assessed by homeostasis model assessment of insulin resistance (HOMA-IR) and β-cell function was assessed by proinsulin/insulin ratio and β-cell%. Results: The prevalence of PDM was 40%. The prevalence of high HOMA-IR was 22.2 and 77.8% in the NG and PDM groups. Compared to NG patients, the PDM group showed higher fasting plasma glucose, HOMA-IR, insulin, and proinsulin, while the prevalence of β-cell dysfunction of 22.2% was lower than the 37% present in the NG group. Conclusion: Increased IR, rather than β-cell dysfunction, is the primary mechanism of PDM in CKD patients.
Optimum Second Screening Point for Detection of Coronary Artery Disease in Hemodialysis Patients without Advanced Coronary Artery Disease
Authors: Joki Nobuhiko , Tanaka Yuri , Ishikawa Hiroyasu , Takahashi Yasunori , Iwakura Yoshitsugu , Masuda Haruka , Inishi Yoji , Hase Hiroki
Published: November 2008

Background: Screening for coronary artery disease (CAD) at the initiation of dialysis is a K/DOQI recommendation. However, it remains unclear when screening for CAD should be repeated in patients without significant disease at the time of starting dialysis. The objectives of this study were to determine: (1) the survival of hemodialysis (HD) patients without CAD at the initiation of dialysis, (2) the major predictors of CAD events, and (3) the best time to repeat screening for CAD after the initiation of HD. Methods: In order to assess the occurrence of de novo major adverse cardiac events (MACE) in HD patients without CAD, we prospectively followed patients who were normal according to screening tests for CAD performed at the initiation of HD. To detect CAD, 177 of 305 new HD patients underwent coronary angiography and/or pharmacologic stress thallium-201 single photon emission computed tomography within 1 month after starting HD. Among these 177 patients, 100 did not have significant CAD and they were followed for a median of 24 months. Results: Five MACE occurred during follow-up, but no events were observed within 1 year after starting HD. All 5 events occurred during the second year of HD (two events occurred immediately after the end of the first year). An increased level of C-reactive protein (CRP) was the only independent predictor of MACE (hazard ratio: 1.39; 95% CI: 1.03–1.78, p = 0.008) according to Cox regression analysis. The optimum cut-off value of CRP for predicting MACE was 3.5 mg/l. The MACE-free rate at 2 years (99 vs. 79%, p = 0.0008) was significantly higher in patients with a CRP level (3.5 mg/l than in those with a level <3.5 mg/l). Conclusion: One year after the initiation of HD could be the optimum time to repeat screening for CAD in patients without disease at the initiation of HD. If the serum CRP level is less than 3.5 mg/l, postponing repeat screening for CAD could be considered.
Biosynthetic Studies on the Collagenous Components of Basement Membranes
Authors: Heathcote Godfrey , Muhammed Sadia , Smith Eileen F. , Grant Michael E.
Published: November 2008

The biosynthesis of the collagenous components of the rat lens capsule and glomerular basement membrane (GBM) has been investigated. Intact lenses, isolated lens capsules and isolated renal glomeruli incorporate [3H]proline into 4-hydroxy[3H]proline containing polypeptides of approximate molecular weight 180,000 (analysed under reducing conditions). These polypeptides are deposited in the deoxycholate-insoluble basement membrane matrix and correspond to subunits of the intact, non-radioactive basement membranes. With time a proportion of the newly synthesised collagenous polypeptides become assembled into high molecular weight aggregates which are stabilized by lysine-and/or hydroxylysine-derived cross-links. Despite the similar patterns of collagen biosynthesis in the rat lens capsule and GBM, the latter has a more complex polypeptide composition the origin of which remains uncertain.
Tissue Culture of Normal Rat Glomeruli
Authors: Foidart J.B. , Pirard Y.S. , Winand R.J. , Mahieu P.R.
Published: November 2008

The biosynthesis of glycosaminoglycans (GAG) by cultivated rat glomerular epithelial and mesangial cells was studied by incorporation of [35S] sulfate or [14C] glucosamine for 48 h. After dialysis, the incubation medium was subjected to digestion with papain. Labeled GAG were isolated from the digests by precipitation with cetylpyridinium chloride and ethanol. Results of cellulose acetate electrophoresis of the isolated ‘epithelial’ GAG fraction revealed the presence of two [14C] spots and one [35S] spot. The [35S] spot was identified as heparan sulfate, because it comigrated with the heparan sulfate standard and it was insensitive to testicular hyaluronidase. One [14C] spot comigrated with the [35S] spot and with the heparan sulfate standard. This GAG fraction did not contain galactosamine. The second [14C] spot was identified as hyaluronic acid, since it comigrated with the hyaluronic acid standard and since it was sensitive to testicular hyaluronidase. Results of cellulose acetate electrophoresis of the isolated ‘mesangial’ GAG fraction revealed the presence of one [14C] spot only. No [35S] spot was detectable. The [14C] spot comigrated with the hyaluronic acid standard and was sensitive to hyaluronidase. The data therefore suggest that the glomerular epithelial cells synthesize and secrete both sulfated GAG (heparan sulfate) and nonsulfated GAG (hyaluoronic acid) into the culture medium, whereas the glomerular mesangial cells synthesize and secrete nonsulfated GAG (hyaluronic acid) only into the culture medium.
Synthesis of Collagen and Fibronectin by Glomerular Cells in Culture
Authors: Foidart J.M. , Foidart J.B. , Mahieu P.R.
Published: November 2008

The biosynthesis of collagen and fibronectin molecules by cultivated glomerular epithelial or mesangial cells was studied at confluency using radioactive proline or lysine as precursors. Collagen represented 0.5% of the total protein synthesized by the glomerular epithelial cells. About 60% of this collagenous protein were associated to the cell layer, whereas about 40% were secreted into the culture medium. Two major collagenous polypeptides were observed with apparent molecular weights of 185K and 170K, and were identified as two gene products of type IV procollagen. They exhibited ratios of 3- to 4-hydroxyproline, of total hydroxyproline to proline, and of hydroxylysine to lysine characteristic of type IV procollagen. They were degraded by bacterial collagenase. The patterns of peptides obtained after digestion of the 185K and 170K chains of this type IV procollagen with pepsin and V8 protease were identical to those obtained after digestion of type IV procollagen chains purified from a murine tumor (EHS sarcoma). Finally, a purified antibody to type IV collagen specifically immunoprecipitated the collagenous protein produced by the glomerular epithelial cells. By contrast, the mesanigal cells synthesized about 5% of collagenous protein. 90% of this collagen were secreted into the cultured medium, whereas about 10% remained associated to the cell layer. Type I, III and IV procollagens were synthesized by the mesangial cells. Fibronectin was found in the medium and cell layer of both epithelial and mesangial cells. Fibronectin molecules were identified by their resistance to bacterial collagenase, their susceptibility to pepsin digestion, and their specific adherence to collagen. It was composed of disulfide-linked peptides of 220K daltons. The data therefore demonstrate that: (a) the glomerular epithelial and mesangial cells synthesize fibronectin molecules and type IV procollagen in vitro; (b) the cultivated mesangial cells also synthesize type I and III collagens. The implications of these findings in certain pathological circumstances, such as diabetes melitus, are now being investigated.
Glycosaminoglycans of the Glomerular Basement Membrane in Normal and Nephrotic States
Authors: Kanwar Yashpal S. , Rosenzweig Lionel J. , Kerjaschki Dontscho I.
Published: November 2008

Alterations in the permeability of the glomerular basement membrane (GBM) towards native ferritin (NF) and iodinated albumin (125I-BSA) following removal of the major glycosaminoglycans (GAGs) of the GBM, heparan sulfate (HS) and hyaluronic acid (HA), were assessed utilizing the techniques of routine electron microscopy and autoradiography, respectively. Kidneys were incubated with heparinase (to degrade the GAGs of the GBM) and subsequently perfused with either NF or 125I-BSA. Control kidneys, which were not treated with heparinase, showed a low permeability to both tracers, with NF being confined to the lamina rara interna and 125I-BSA exhibiting a low level of passage into the urinary spaces (as indicated by a low density of autoradiographic grains over the urinary spaces). After heparinase treatment there was an increase in the permeability of the GBM such that both NF and l25I-BSA passed through the GBM in larger quantities and entered the urinary spaces. Perfusion of cationized ferritin (CF) into control kidneys revealed this probe to bind to the HS-rich anionic sites present within the GBM. Treatment with heparinase resulted in an abolition of the CF binding thereby indicating that the sites are composed mainly of HS and that HS plays a key role in establishing the permeability properties of the GBM. The changes in the pattern of distribution and density of the anionic sites of the GBM following induction of nephrosis was also studied. Animals were rendered nephrotic by subcutaneous injections of an aminonucleoside of puromycin and their kidneys subsequently perfused with either CF or cationized cytochrome c1. No difference in either the pattern of distribution or density of the anionic sites in the GBM of nephrotic kidneys was observed when compared to nonnephrotic controls; thus indicating that the proteinuria associated with aminonucleoside nephrosis might be due to changes in components of the glomerular capillary wall other than the anionic sites.
Concentration of Renin in the Renal Interstitium, as Reflected in Lymph
Authors: O’ Morchoe Charles C.C. , O’Morchoe Patricia J. , Albertine Kurt H. , Jarosz Harriet M.
Published: November 2008

The relationship between renin activity in renal venous plasma and in renal interstitial fluid, as reflected in the hilar lymph, was observed. Control measurements in 28 dogs demonstrated that renin levels in the hilar lymph were 3.5 ± (SEM)0.4 times higher than in renal venous plasma and 6.1 + 1.0 times higher than in arterial plasma. Renin activity was increased to varying levels by raising ureteric pressure and by the administration of different doses of furosemide. Under all conditions, the changes in renin activity in renal venous plasma and in the interstitium, as reflected in the hilar lymph, were in parallel although often more marked in the hilar lymph. Thus, the study shows that under conditions of increased renin release, the interstitial renin activity rises in consort with increases in arteriovenous plasma differences. This increase in interstitial renin activity occurred even under circumstances when renal blood flow is known to increase, thereby suggesting that angiotensin generated in the interstitium may have little effect on the cortical arteriolar caliber.
Renal Function in the Term Pregnant Rat: A Micropuncture Study
Authors: Churchill Susanne E. , Bengele Howard H. , Alexander Edward A.
Published: November 2008

The purpose of this study was to define individual nephron function and salt and fluid reabsorption in the term pregnant rat utilizing standard micropuncture techniques. The studies were performed at the time of maximal sodium retention and when extracellular fluid volume was significantly increased. During micropuncture in 7 pregnant and 9 non-pregnant rats, we found no difference, respectively, in GFR 1.04 + 0.06 vs. 1.13 ± 0.06 ml/min/kidney or nephron GFR 35 ± 0.9 vs. 33 ± 1 ml/min. Fractional and absolute Na reabsorption was also not significantly different in the proximal tubule or the loop of Henle. Along the distal tubule, fractional reabsorption was higher in pregnancy, 71 + 3 vs. 62 + 4 but not statistically different, 0.05 < p < 0.10. Beyond the late distal tubule absolute delivery and reabsorption were greater in the nonpregnant rats. Distal nephron potassium secretion was similar in both groups. In anesthetized rats during clearance studies but without surgery for micropuncture, GFR in the pregnant group was significantly higher than the nonpregnant rats, 1.65 + 0.06 vs. 1.28 + 1.10ml/min/kidneys as was tubular reabsorption of sodium. We conclude that pregnant rats exhibit glomerular tubular balance and that potassium handling along the superficial nephron is unaffected by pregnancy. The sodium retention of pregnancy appears to occur because of the failure of inhibition of tubular sodium reabsorption, a response which is normally expected when extracellular volume is expanded.
Thyroidal Regulation of Alkaline Phosphatase Activity in Kidney Cortex Brush Border Membranes
Authors: Capasso G. , Kinne R. , Moewes B. , Anastasio P. , De Santo N.G. , Giordano C.
Published: November 2008

In kidney cortex homogenates and brush border membranes of hypothyroid rats undergoing T3 substitution with 50 µg/kg BW a day for 1–4 days, a significant decrease of alkaline phosphatase activity was observed. The data indicate that thyroid hormones may affect the luminal membrane.
Single-Nephron Hemodynamics in One-Kidney One-Clip Hypertension in the Rat
Authors: Schwietzer Gerd , Gertz† Karl-Heinz
Published: November 2008

Determinants of glomerular ultrafiltration were studied by micropuncture in clamped kidneys of one-kidney Goldblatt rats (n = 10, mean arterial pressure (MAP) = 183 + 18 (SD) mm Hg) and in control kidneys of unilateral nephrectomized rats (n = 14, MAP = 120 ± 14 mm Hg). Following saralasin infusion, no significant MAP change occurred in either group. Renal perfusion pressure of clamped kidneys (115 ± 13 mm Hg) was not different from MAP in controls. Hydrostatic pressure in glomerular capillaries in clamped kidneys was not different from that in controls (60.9 + 2.1 vs. 61.7 + 3.5 mm Hg). Early proximal flow rate, as a measure for single-nephron GFR, was decreased to 29.5 + 1.5 vs. 36.6 + 4.4 nl/min in controls (p < 0.01). Total renal resistance was increased by 102% in the hypertensive group, mainly due to the stenosis (75%) rather than the renal vasculature (27%). Due to a predominant increase of postglomerular vascular resistance, filtration fraction was increased in clamped kidneys (0.37 + 0.05 vs. 0.34 + 0.06, p < 0.001). Single nephron glomerular plasma flow was decreased to 158 + 23.5 vs. 209 + 45.1 nl/min in controls (p < 0.001). Efferent net ultrafiltration pressure did not differ significantly from zero in either group, i.e. filtration equilibrium was achieved. These results indicate an increased vascular resistance in clamped kidneys, which is caused by a preferential efferent vasocon-striction. This pattern of the vascular bed helps to prevent a further reduction of GFR despite a decrease of blood flow.
Inhibitory Effect of Lithium on p-Aminohippurate Transport in Rat Kidney Cortex in vitro
Authors: Gemba Munekazu , Tachibana Akemi , Sugihara Kumi , Hori Mitsuhiko , Nakajima Mayumi
Published: November 2008

The effect of lithium on p-aminohippurate (PAH) transport was studied using slices and basolateral membrane vesicles prepared from rat kidney cortex. The addition of lithium in concentrations ranging from 0.5 to 5 mM caused a concentration-dependent inhibition of PAH accumulation in the slices. Lithium inhibited PAH accumulation in the slices, not only during the rapid uptake period (after 10 min) but also during the approach to equilibrium (after 30 min). The effect of lithium (2 mM) in the slices was irreversible. The inhibitory effect of lithium was not the result of changes in the water distribution and the concentrations of ATP, sodium and potassium in the slices during incubation. The effect of lithium on the kinetic parameters for PAH accumulation was to decrease Vmax, while apparent Km remained constant. There was no lithium effect on the efflux of PAH from the slices back into the incubation medium, indicating that lithium inhibited PAH influx to the kidney cells. No evidence was obtained to indicate that lithium (1 mM) directly affected PAH uptake by isolated basolateral membrane vesicles. These results suggest that lithium seems to affect metabolism linked to the carriers for PAH transport other than ATP production and sodium gradient and then seems to decrease the mobility of the carriers in the membranes.
Complex Physiological and Biochemical Action of Aldosterone in Toad Urinary Bladder and Mammalian Renal Collecting Duct Cells
Authors: Minuth Will W. , Steckelings Ulrike , Gross Peter
Published: November 2008

Since the discovery of the steroid hormone aldosterone nearly 35 years ago, our knowledge on the cellular actions of aldosterone is still incomplete. Most of the present physiological and biochemical knowledge about the antinatriuretic action was revealed by investigations on amphibian tight epithelia, in particular the toad urinary bladder. Less biochemical information was obtained from mammalian tissue such as microdissected renal tubules and cultured cells. In our opinion, it is questionable whether de novo synthesis of cell proteins – induced by aldosterone – can explain all of the hormonal effects to increase the Na+ transport. In the present paper we try to analyze the wide and contradictory field of biochemical data about the action of aldosterone on the increase in Na+ transport in renal cells in an attempt to incorporate this information into an extended working hypothesis. We suggest distinguishing principally between an early and a late biochemical response phase. We speculate that aldosterone may act by a two-step mechanism: the early and late aldosterone-induced proteins.