bluuebunny/crossref_metadata_2025 huggingface dataset:
Follicular development in European ground squirrels (Spermophilus citellus) in different phases of the annual cycle
Authors: Millesi Eva , Strauss Anna , Burger Tamara , Hoffmann Ilse E , Walzl Manfred
Published: May 2008

In seasonally breeding mammals, in particular hibernators, reproduction underlies severe energetic and temporal constraints to enable the allocation of sufficient body fat reserves before winter. Thus, the timing of conception in spring can be crucial in terms of reproductive success. This study investigates follicular development in European ground squirrels (Spermophilus citellus) in three phases of the annual cycle: at vernal emergence, after weaning the offspring and shortly before hibernation. The animals were kept in outdoor enclosures within the natural habitat of the species. They were captured in weekly intervals, weighed and reproductive status was determined. Unilateral ovariectomy was scheduled such that the three periods were sampled. Numbers and diameters of tertiary follicles (TF) and corpora lutea (CL) in each ovary were determined, and plasma oestradiol and progesterone levels were analysed. The highest numbers of TF, including Graafian follicles, were found in ovaries at vernal emergence. During post-lactation, the number of TF was lower and active CL appeared in the investigated ovaries. Shortly before hibernation, active CL were present, but luteolysis had started in some individuals. Both oestradiol and progesterone secretion peaked after the termination of lactation and decreased before hibernation. The results demonstrate a second oestrus cycle in European ground squirrels after weaning, including an active luteal phase. This non-reproductive oestrus cycle with its endocrine output is an intriguing phenomenon. It may positively affect both prehibernatory fattening and reproduction in the subsequent season.
Expression of a hyperactive androgen receptor leads to androgen-independent growth of prostate cancer cells
Authors: Hsieh Chen-Lin , Cai Changmeng , Giwa Ahmed , Bivins Aaronica , Chen Shao-Yong , Sabry Dina , Govardhan Kumara , Shemshedini Lirim
Published: May 2008

Cellular changes that affect the androgen receptor (AR) can cause prostate cancer to transition from androgen dependent to androgen independent, which is usually lethal. One common change in prostate tumors is overexpression of the AR, which has been shown to lead to androgen-independent growth of prostate cancer cells. This led us to hypothesize that expression of a hyperactive AR would be sufficient for androgen-independent growth of prostate cancer cells. To test this hypothesis, stable lune cancer prostate (LNCaP) cell lines were generated, which express a virion phosphoprotein (VP)16-AR hybrid protein that contains full-length AR fused to the strong viral transcriptional activation domain VP16. This fusion protein elicited as much as a 20-fold stronger transcriptional activity than the natural AR. Stable expression of VP16-AR in LNCaP cells yielded androgen-independent cell proliferation, while under the same growth conditions the parental LNCaP cells exhibited only androgen-dependent growth. These results show that expression of a hyperactive AR is sufficient for androgen-independent growth of prostate cancer cells. To study the molecular basis of this enhanced growth, we measured the expression of soluble guanylyl cyclase-α1 (sGCα1), a subunit of the sGC, an androgen-regulated gene that has been shown to be involved in prostate cancer cell growth. Interestingly, the expression of sGCα1 is androgen independent in VP16-AR-expressing cells, in contrast to its androgen-induced expression in control LNCaP cells. RNAI-dependent inhibition of sGCα1 expression resulted in significantly reduced proliferation of VP16-AR cells, implicating an important role for sGCα1 in the androgen-independent growth of these cells.
Intracerebroventricular injection of citrate inhibits hypothalamic AMPK and modulates feeding behavior and peripheral insulin signaling
Authors: Stoppa Graziela R , Cesquini Maristela , Roman Erika A , Prada Patrícia O , Torsoni Adriana S , Romanatto Talita , Saad Mario J , Velloso Licio A , Torsoni Marcio A
Published: May 2008

We hypothesized that citrate might modulate the AMP-activated protein kinase/acetyl-CoA carboxylase (AMPK)/(ACC) pathway and participate in neuronal feeding control and glucose homeostasis. To address this issue, we injected citrate into the lateral ventricle of rats. Intracerebroventricular (ICV) injection of citrate diminished the phosphorylation of hypothalamic AMPK/ACC, increased the expression of anorexigenic neuropeptide (pro-opiomelanocortin and corticotropin-releasing hormone), elevated the level of malonyl-CoA in the hypothalamus, and reduced food intake. No change was observed in the concentration of blood insulin after the injection of citrate. With a euglycemic–hyperinsulinemic clamp, the glucose infusion rate was higher in the citrate group than in the control group (28.6±0.8 vs 19.3±0.2 mU/kg body weight/min respectively), and so was glucose uptake in skeletal muscle and the epididymal fat pad. Concordantly, insulin receptor (IR), IR substrate type 1 (IRS1), IRS2, and protein kinase B (AKT) phosphorylation in adipose tissue and skeletal muscle was improved by citrate ICV treatment. Moreover, the treatment with citrate for 7 days promoted body weight loss and decreased the adipose tissue. Our results suggest that citrate and glucose may serve as signals of energy and nutrient availability to hypothalamic cells.
Soil Carbon and Nitrogen Changes in Long‐Term Continuous Lowland Rice Cropping
Authors: Pampolino Mirasol F. , Laureles Eufrocino V. , Gines Hermenegildo C. , Buresh Roland J.
Published: May 2008

Rice (Oryza sativaL.), the main staple food in Asia, is typically produced on submerged anaerobic soils, which generally have slower decomposition of soil organic matter (SOM) than aerobic soils. We sampled four long‐term experiments in the Philippines, with two or three rice crops grown each year with continuous or near‐continuous soil submergence, to determine the effect of fertilizer management on long‐term changes in soil C and N and on C and N balances. Soils were an Aquandic Epiaquoll, an Entic Pellustert, and a Typic Pelludert; soil pH ranged from 5.9 to 6.7. After 17 to 21 yr of continuous rice cultivation, the concentration of total soil organic C (SOC) and total soil N (NT) in the topsoil (0–20 cm) were greater with N–P–K fertilization than without fertilization. During 15 yr of additional continuous rice cropping, topsoil SOC and NTwere consistently maintained or increased regardless of N–P–K fertilizer regime. Topsoil SOC increased up to 10% in an experiment with three rice crops per year and removal of all aboveground plant biomass after each crop. Subsoil SOC and NT(20–80 cm) were not affected by fertilization. The N balances indicated that biological N2fixation averaged 19 to 44 kg N ha−1crop−1across the four experiments. Anaerobic N mineralization (ANM) in the topsoil was maintained during 15 yr of continuous rice cropping with N–P–K fertilization in all four experiments. The results suggest that continuous cultivation of irrigated rice with balanced fertilization on submerged soils maintained or slightly increased SOM and maintained soil N‐supplying capacity.
Upward Infiltration into Porous Media as Affected by Wettability and Anionic Surfactants
Authors: Ishiguro Munehide , Fujii Tomokazu
Published: May 2008

The influence of surfactants on water infiltration in soil is not fully understood. The objective of this study was to propose a model for evaluating effects of an anionic surfactant on upward infiltration under saturated conditions in porous materials with highly contrasting wettability. The simplified equation for upward infiltration based on Darcy's law is equivalent to the widely used Washburn equation. We experimentally determined upward infiltration of sodium dodecyl sulfate (SDS) solution (0–700 mol m−3) into 60‐cm‐long, 2‐cm‐diameter columns filled with air‐dry materials (glass beads, sand, leaf mold, peat moss, or polyethylene particles). In hydrophilic glass beads and sand, the infiltration rate decreased as the SDS concentration increased due to a decrease in solution surface tension (from 72 to 38 mN m−1). The proposed model could describe the infiltration in all materials and at all concentrations when fitting to the initial parts of the curve of infiltration front vs. time. Contact angles were obtained by fitting the model to the measured height of the infiltration front in the saturated range as a function of time. In columns filled with hydrophobic materials, the infiltration rate increased with SDS concentration, corresponding with a decrease in contact angles from >125 to 69° for polyethylene particles and from 102 to 43° for peat moss. In leaf mold, the infiltration rate decreased as the SDS concentration increased, probably due to swelling. The proposed equation was found useful for calculating saturated hydraulic conductivity and contact angles but limited in the case of swelling porous material.
Organic Amendments Influence Soil Organic Carbon Pools and Rice–Wheat Productivity
Authors: Majumder Bidisha , Mandal Biswapati , Bandyopadhyay P. K. , Gangopadhyay A. , Mani P. K. , Kundu A. L. , Mazumdar D.
Published: May 2008

Soil organic C (SOC) pools under long‐term management practices provide information on C sequestration pathways, soil quality maintenance, and crop productivity. Farmyard manure (FYM), paddy straw (PS), and green manure (GM) along with inorganic fertilizers were used in a 19‐yr‐old rice (Oryza sativaL.)–wheat (Triticum aestivumL.) cropping system in subtropical India to evaluate their impact on SOC stock, its different pools—total organic C (Ctot); oxidizable organic C (Coc) and its four fractions of very labile (Cfrac1), labile (Cfrac2), less labile (Cfrac3), and nonlabile C (Cfrac4); microbial biomass C (Cmic); and mineralizable C (Cmin). Cropping with only N–P–K fertilization just maintained SOC content, while N–P–K plus organics increased SOC by 24.3% over the control, their relative efficacy being FYM > PS > GM. A minimum of 3.56 Mg C ha−1yr−1was required to be added as organic amendments to compensate for SOC loss from cropping. The passive (Cfrac3+ Cfrac4) pool and Cminconstituted about 39 and 11.5%, respectively, of CtotOrganics contributed toward the passive pool in the order FYM > PS > GM. Most of the pools were significantly (P= 0.005) correlated with each other. Yield and sustainable yield index were strongly related with Cfrac1, Coc, Cmic, and CminResults suggest Cfrac1as a useful indicator for assessing soil health, and balanced fertilization with FYM as suitable management for sustaining crop productivity of the rice–wheat system.
Carbon Sequestration and Dynamics of Two Irrigated Agricultural Soils in California
Authors: Wu Laosheng , Wood Yvonne , Jiang Pingping , Li Lianqin , Pan Genxing , Lu Jianhang , Chang Andrew C. , Enloe Heather A.
Published: May 2008

Irrigation in semiarid regions can alter soil C sequestration processes compared with those of native soils. To better understand the effect of these altered processes, we studied the C sequestration and dynamics of two soils from major irrigated agricultural regions of California (the San Joaquin Valley and the Imperial Valley). Soils were sampled from selected native and cultivated fields to represent a span of almost a century of irrigated farming. Field soil samples were analyzed for total soil C and soil inorganic C as carbonate (SIC). Soil organic C (SOC) was then calculated from the measured data. Results showed that SOC stock increased above that stored in the native soil after five decades of irrigated farming. The SIC stock showed opposing trends within the top meter of the two studied soils: a decrease was measured after 55 yr in the San Joaquin Valley soil, while SIC in the Imperial Valley soil increased after 85 yr of irrigated agriculture and appears to represent a significant form of sequestered soil C. Our results indicate that long‐term irrigated farming can significantly increase SOC due primarily to SOC added below the 10‐cm soil depth, while significant increases in SIC may be partially due to the conversion of increased soil CO2to carbonates under a regime of Colorado River irrigation water. Thus, when considering C sequestration in irrigated agriculture in semiarid regions, it is important to determine levels of both SOC and SIC.
Estimation of Vermiculite Content Using Rubidium‐Fixation Procedures in Four California Soils
Authors: Murashkina M. A. , Southard R. J. , Shiraki R.
Published: May 2008

Quantification of phyllosilicates in soils often depends on a combination of methods, including x‐ray diffraction (XRD), cation exchange and fixation capacities, and microscopy. We examined a Rb fixation method to quantify vermiculite content in California soils derived from granitic and nongranitic alluvium. Whole soil (<2‐mm) samples were saturated with Rb and heated to 110°C followed by Rb displacement with NH4 (Rb110°C). Fixed Rb was determined directly by instrumental neutron activation analysis. The amount of vermiculite (g kg−1) was calculated as fixed Rb content (cmolc kg−1)/0.154 (based on a cation exchange capacity for vermiculite of 154 cmolc kg−1). For comparison, Rb fixation was also estimated after a 1‐h incubation (Rb1hr) with 2 mmol L−1 RbCl followed by a 30‐min extraction with NH4Cl. The more rigorous heating treatment (Rb110°C) fixed almost 35 times more Rb than the 1‐h method. The Rb110°C fixation was positively and significantly correlated with soil clay content. The XRD data showed, however, that clay fractions were dominated by smectite, mica, and chlorite, while vermiculite, the major K‐ and Rb‐fixing mineral, was a dominant mineral in most silt fractions. The Greene‐Kelly test showed that, in soils with smectitic clays, some of the charge originated in the tetrahedral sheet. Silt content was correlated with Rb1hr fixation but was not correlated with Rb110°C fixation. Our data suggest that Rb fixation by heating to 110°C overestimates the amount of vermiculite when tetrahedrally substituted smectites are dominant in clay fractions, and includes fixation by minerals in the silt fraction.
Soil Nitrogen and Carbon after Twenty Years of Riparian Forest Development
Authors: Bush J. K.
Published: May 2008

Soil C and N were measured from a chronosequence of adjacent riparian forest sites located along the floodplain terrace of the San Antonio River. The communities were 25, 39, 45, 47, 49, and 53 yr past long‐term farmland use. Four of these sites (25, 45, 49, and 53 yr old) were also sampled 20 yr ago. Soil C was significantly greater after 20 yr of community development; however, the increase was dependent on the community age. Soil C increased by 38 g kg−1in the 49‐yr‐old community during the 20‐yr period, but only 11 to 15 g kg−1in the 25‐, 45‐, and 53‐yr‐old communities. Soil N was significantly greater (1.7–2.5 g kg−1) after 20 yr of development for communities 25, 45, and 49 yr old. In the oldest community (53 yr old), no significant increase was seen in soil N after 20 yr. No significant spatial differences [underneath the canopy ofAcacia farnesiana(L.) Willd. vs. intercanopy grassland] were found in soil C and N in the 25‐yr‐old community. The late successional dominantCeltis laevigataWilld., total woody plant density, and total woody plant basal area could be explained by soil C or N. Changes in soil C and N through time parallel other studies, increasing through the early‐ and mid‐successional stages and decreasing from the mid‐ to late‐successional stages. Spatial differences in soil C and N that existed in the 15‐yr‐old community disappeared in the 25‐yr‐old community asA. farnesianabasal area increased from 0.7 to13 m2ha−1
Tectonic Inclusions in Serpentinite Landscapes Contribute Plant Nutrient Calcium
Authors: McGahan Donald G. , Southard Randal J. , Claassen Victor P.
Published: May 2008

Serpentinite‐derived soils give rise to botanically distinct systems primarily because of inadequate parent material Ca content. We hypothesized that Ca content varies widely in what have been mapped as soils derived from serpentinite. An exchangeable Ca/Mg ratio <0.7 is often used to relate the imbalance of these nutrient elements in serpentinite‐derived soils. We sampled six parent materials and soils from the Coast Ranges of California in Henneke soil series (clayey‐skeletal, magnesic, thermic Lithic Argixerolls) modal location map unit polygons. Parent material total CaO content varied from 1.0 to 230 mg kg−1, and CaO/MgO varied from <0.1 to 4. A combination of x‐ray diffraction (XRD), polarized light microscopy (PLM), and electron microscopy was used to identify the Ca‐bearing accessory minerals diopside, grossularite, andradite, and tremolite. Accessory mineral content was often too low to be detected by XRD or minerals were too finely disseminated and difficult to detect in thin section by PLM. Electron microscopy, in concert with XRD and PLM, was needed to fully characterize the mineral assemblage. Two sites, Napa and Tehama, contained no serpentine minerals, were not serpentinites, and were tectonic inclusions in the serpentinite landscape. Napa rocks contained almost no Ca‐bearing minerals and would be identified as a serpentinite if relying on elemental analysis CaO/MgO ratio alone. Tectonic inclusions and Ca‐bearing accessory minerals affect Ca distribution and presumably its availability for plants. Careful mineralogical analysis may be required to identify Ca‐bearing accessory minerals.
Comparison of Galvanic and Chemi‐Luminescent Sensors for Detecting Soil Air Oxygen in Flood‐Irrigated Pecans
Authors: Kallestad J. C. , Sammis T. W. , Mexal J. G.
Published: May 2008

Low soil O2 levels have been shown to limit growth in pecan [Carya illinoinensis (Wangenh.) K. Koch] seedlings and may limit yield in mature trees. To assess changes in the gas‐phase O2 concentration in a pecan orchard soil in response to flood irrigations throughout a growing season, two types of O2 sensor were field tested: a galvanic O2 sensor and a spectrometer‐coupled chemical sensor (FOXY sensor). Galvanic sensors, housed in diffusion chambers, were buried at four depths and a datalogger recorded continuous voltage output. The FOXY O2 sensor was utilized as part of a mobile O2 detection system to field analyze gas samples withdrawn periodically from buried diffusion chambers. The FOXY sensor was found to be unstable, however, and difficult to calibrate under conditions of changing temperature and humidity. Laboratory experiments simulating submersion of the galvanic sensor indicated that voltage outputs were comparable to the range observed in the field, but the absence of diurnal concentration fluctuations, typically found in soil measurements, provided a way to discriminate between normal and aberrant output. The responsiveness of the galvanic sensor and its capability to continuously gather hourly data makes it superior to methods dependent on manual sample collection. Galvanic sensors were adequately suited for long‐term in situ use in agricultural soil when housed in appropriate diffusion chambers. Higher costs, limited access to diffusion chambers during flood periods, and high variability associated with manually collected data make the FOXY mobile O2 detection system comparatively less optimal for use in agricultural settings.
Total Phosphorus Determination in Colloid‐Containing Soil Solutions by Enhanced Persulfate Digestion
Authors: Pagel Holger , Ilg Katrin , Siemens Jan , Kaupenjohann Martin
Published: May 2008

It is unclear whether persulfate digestions completely liberate P associated with mineral colloids in soil solutions and aqueous soil extracts. We tested a modified persulfate digestion using aqueous soil extracts and suspensions of goethite, gibbsite, illite, and montmorillonite that were exposed to 24 μmol P L−1 as orthophosphate (ortho‐P) or myo‐inositol hexaphosphate (IHP). Digestion was performed by autoclaving (121°C, 60 min) 5 mL of extract or suspension after the addition of 1 mL of solution, which contained 150 mmol L−1 K2O8S2 and 180 mmol L−1 H2SO4 Subsequently, 0.7 mL of 188 mmol L−1 ascorbic acid was added and the sample was heated in a water bath at 95°C for 60 min. For the samples where P was sorbed onto goethite and gibbsite, recoveries of total P were 97.2 ± 3.7% (ortho‐P) and 102 ± 3.7% (IHP). For the samples where P was sorbed onto clay minerals, average total P recoveries were 99.2 ± 5.1% (ortho‐P) and 106 ± 3.0% (IHP). No differences between total P concentrations measured in persulfate‐digested soil extracts or with an additional digestion with HF and HNO3 were detected.
Accounting for Bias and Boundary Condition Effects on Measurements of Saturated Core Hydraulic Conductivity
Authors: Madsen Matthew D. , Chandler David G. , Reynolds W. Daniel
Published: May 2008

Most hydrologic studies require knowledge of saturated soil hydraulic conductivity, Ks This parameter is often measured using saturated soil cores and a constant applied hydraulic head device. A standard approach to reduce uncertainty in the result is to conduct replicate tests at a single hydraulic head gradient. Low‐permeability soils are often tested at large hydraulic head gradients to decrease measurement time. Our objective was to test the common assumptions implicit in calculating Ks from constant‐head laboratory tests, i.e., the theoretical linear relationship between head gradient and flux density exists in experimental data, and the relationship passes through the origin. In this study, we used linear regression analysis to test these assumptions and determined Ks from a broad range of head gradients for: 4.5‐cm (diameter) by 10‐cm (height) intact cores of sandy loam soil; 10‐cm (diameter) by 10‐cm (height) intact cores of clay loam soil; and repacked sand columns of various sizes. We found nonlinear relationships between hydraulic head gradient (i) and flux density (q) for tests conducted on intact cores of both soils, especially for head gradients greater than unity. When we calculated Ks by linear regression of data from intact cores, we found average values approximately one‐third greater than the “standard” method of averaging several replicate tests at a single hydraulic head. The difference between the regression and standard analyses was attributed to experimental bias, which is removed by the linear regression. Although no consistent i or q “thresholds” were identified to predict the onset of nonlinearity in i vs. q data, the intact core results imply that i < 1 and q < 5 × 10−3 cm s−1 may be advisable.
Modification of the Illinois Soil Nitrogen Test to Improve Measurement Precision and Increase Sample Throughput
Authors: Spargo John T. , Alley Marcus M.
Published: May 2008

Quantification of organic N mineralization during the corn (Zea mays L.) growing season should improve the precision of fertilizer N recommendations. The Illinois soil N test (ISNT) has shown promise in some regions as a useful tool for estimating mineralizable soil N; however, the procedure needs to be modified for use in routine soil testing labs that must process hundreds of samples per day. The assay determines alkali hydrolyzable N by treating 1 g of soil with 10 mL of 2 mol L−1 NaOH in a 473‐mL wide‐mouth Ball jar, and heating for 5 h at 50°C on a hot plate to liberate (NH4+ + amino sugar)–N as gaseous NH3, which is collected in H3BO3 solution and subsequently determined by acidimetric titration. The objectives of this study were to determine if variance in measurement values could be reduced and sample throughput increased while maintaining accuracy by using an incubator to replace the hot plate as the heat source. Thirty‐five soils collected from N‐response trials in Virginia were used in this study. Jars were heated in an incubator at 50°C for 5, 6, 7, 8, 9, 10, or 15 h. Soil samples were also analyzed with the unmodified method for comparison. All determinations were conducted in triplicate. Use of an incubator set to 50°C reduced the total recovery of N from the samples, but increasing the diffusion period increased N recovery. The 15‐h diffusion period resulted in quantitative recovery of ISNT‐N with significantly (P < 0.05) improved measurement precision compared with the unmodified method (CV = 4.3 vs. 7.4, respectively). Modifying the ISNT by using an incubator instead of a hot plate increases measurement precision and allows greater sample throughput.
Implication of Genetic Variants Near TCF7L2, SLC30A8, HHEX, CDKAL1, CDKN2A/B, IGF2BP2, and FTO in Type 2 Diabetes and Obesity in 6,719 Asians
Authors: Ng Maggie C.Y. , Park Kyong Soo , Oh Bermseok , Tam Claudia H.T. , Cho Young Min , Shin Hyoung Doo , Lam Vincent K.L. , Ma Ronald C.W. , So Wing Yee , Cho Yoon Shin , Kim Hyung-Lae , Lee Hong Kyu , Chan Juliana C.N. , Cho Nam H.
Published: May 2008

OBJECTIVE— Recent genome-wide association studies have identified six novel genes for type 2 diabetes and obesity and confirmed TCF7L2 as the major type 2 diabetes gene to date in Europeans. However, the implications of these genes in Asians are unclear.

RESEARCH DESIGN AND METHODS— We studied 13 associated single nucleotide polymorphisms from these genes in 3,041 patients with type 2 diabetes and 3,678 control subjects of Asian ancestry from Hong Kong and Korea.

RESULTS— We confirmed the associations of TCF7L2, SLC30A8, HHEX, CDKAL1, CDKN2A/CDKN2B, IGF2BP2, and FTO with risk for type 2 diabetes, with odds ratios ranging from 1.13 to 1.35 (1.3 × 10−12 < Punadjusted < 0.016). In addition, the A allele of rs8050136 at FTO was associated with increased BMI in the control subjects (Punadjusted = 0.008). However, we did not observe significant association of any genetic variants with surrogate measures of insulin secretion or insulin sensitivity indexes in a subset of 2,662 control subjects. Compared with subjects carrying zero, one, or two risk alleles, each additional risk allele was associated with 17% increased risk, and there was an up to 3.3-fold increased risk for type 2 diabetes in those carrying eight or more risk alleles. Despite most of the effect sizes being similar between Asians and Europeans in the meta-analyses, the ethnic differences in risk allele frequencies in most of these genes lead to variable attributable risks in these two populations.

CONCLUSIONS— Our findings support the important but differential contribution of these genetic variants to type 2 diabetes and obesity in Asians compared with Europeans.
PANIC-ATTAC: A Mouse Model for Inducible and Reversible β-Cell Ablation
Authors: Wang Zhao V. , Mu James , Schraw Todd D. , Gautron Laurent , Elmquist Joel K. , Zhang Bei B. , Brownlee Michael , Scherer Philipp E.
Published: May 2008

OBJECTIVE—Islet transplantations have been performed clinically, but their practical applications are limited. An extensive effort has been made toward the identification of pancreatic β-cell stem cells that has yielded many insights to date, yet targeted reconstitution of β-cell mass remains elusive. Here, we present a mouse model for inducible and reversible ablation of pancreatic β-cells named the PANIC-ATTAC (pancreatic islet β-cell apoptosis through targeted activation of caspase 8) mouse.

RESEARCH DESIGN AND METHODS—We efficiently induce β-cell death through apoptosis and concomitant hyperglycemia by administration of a chemical dimerizer to the transgenic mice. In contrast to animals administered streptozotocin, the diabetes phenotype and β-cell loss are fully reversible in the PANIC-ATTAC mice, and we find significant β-cell recovery with normalization of glucose levels after 2 months.

RESULTS—The rate of recovery can be enhanced by various pharmacological interventions with agents acting on the glucagon-like peptide 1 axis and agonists of peroxisome proliferator–activated receptor-γ. During recovery, we find an increased population of GLUT2+/insulin− cells in the islets of PANIC-ATTAC mice, which may represent a novel pool of potential β-cell precursors.

CONCLUSIONS—The PANIC-ATTAC mouse may be used as an animal model of inducible and reversible β-cell ablation and therefore has applications in many areas of diabetes research that include identification of β-cell precursors, evaluation of glucotoxicity effects in diabetes, and examination of pharmacological interventions.
Relationship of Abdominal Visceral and Subcutaneous Adipose Tissue With Lipoprotein Particle Number and Size in Type 2 Diabetes
Authors: Sam Susan , Haffner Steven , Davidson Michael H. , D'Agostino Ralph B. , Feinstein Steven , Kondos George , Perez Alfonso , Mazzone Theodore
Published: May 2008

OBJECTIVE—Insulin resistance and type 2 diabetes are associated with an atherogenic lipoprotein profile. We examined the role of visceral and subcutaneous fat depots, independent of BMI, on the dyslipidemia associated with type 2 diabetes.

RESEARCH DESIGN AND METHODS— A total of 382 subjects with type 2 diabetes underwent abdominal computed tomography to evaluate subcutaneous (SAT) and visceral adipose tissue (VAT) distribution and had anthropometric measurements to determine BMI and waist and hip circumference. Fasting blood was obtained for lipoprotein particle number and size using nuclear magnetic resonance spectroscopy. The relationship of lipoprotein particle number and size with BMI, SAT, and VAT was examined using multivariable regression models adjusted for age, sex, diabetes therapy, duration of diabetes, smoking, statin use, and A1C levels. The relation of VAT to lipoprotein particle number and size was further evaluated after the addition of BMI, BMI plus SAT, or BMI plus homeostatis is model assessment of insulin resistance (HOMA-IR) to the model.

RESULTS—VAT was positively related to VLDL particle number (P < 0.0001), LDL particle number (P < 0.01), and VLDL size (P < 0.0001) and negatively related to LDL size (P < 0.0001) and HDL size (P < 0.0001). These relationships remained unchanged after addition of BMI and SAT to the model. After addition of HOMA-IR, VAT remained positively related to VLDL particle number (P < 0.0001) and size (P < 0.01) and negatively related to LDL and HDL particle size (P < 0.0001 for both comparisons). Neither BMI nor SAT was independently related to lipoprotein parameters.

CONCLUSIONS—In patients with type 2 diabetes, higher VAT independent of BMI was associated with higher VLDL and LDL particle number, larger VLDL particles, and smaller LDL and HDL particles. This lipoprotein pattern has been associated with increased risk for atherosclerosis and cardiovascular disease.
Analysis of hull resistance of pushed barges in shallow water
Authors: Tabaczek Tomasz , Kulczyk Jan , Zawiślak Maciej
Published: May 2008

Analysis of hull resistance of pushed barges in shallow water

These authors performed a set of numerical calculations of water flow around pushed barges differing to each other by bow forms. The calculations were executed by means of FLUENT computer software. Turbulent free-surface flow of viscous liquid was considered. In this paper the calculated values of barge hull resistance split into bow, cylindrical and stern part components, have been compared and presented.
Stiffness characteristics and thermal deformations of the frame of high power marine engine
Authors: Murawski Lech , Szmyt Marek
Published: May 2008

Stiffness characteristics and thermal deformations of the frame of high power marine engine

In the subject-matter literature detail data on stiffness of the crankshaft foundation connected with the frame of marine main engine are still lacking. Thermal deformation models of the engine's casing, proposed by engine producers, are excessively simplified. However the parameters are crucial for the shaft-line alignment analysis as well as for the analysis of interactions between the shaft-line and engine crankshaft, especially in the case of high power engines. This paper presents a determination method of the marine engine body characteristics as well as results of example computations performed for a Sulzer 7 RTA 84 C engine installed on a ~3000 TEU container ship. It has been demonstrated that the producer's assumption about parallel displacement of the crankshaft axis in thermal working conditions is too rough. The thermal deformation of the engine is of hogging character, which results in significant change of the moment load exerted on the crankshaft and shaft line. The stiffness parameters recommended by the producers for the shaft-line alignment are estimated correctly, however they represent only engine's body flexibility, without taking into account ship's hull flexibility.
Usefulness assessment of standard measuring instruments installed on sea-going ships to perform energy measurements
Authors: Górski Zygmunt , Cwilewicz Romuald
Published: May 2008

Usefulness assessment of standard measuring instruments installed on sea-going ships to perform energy measurements

The presented work is a contribution to discussion on usefulness of application of measurement instrumentation used on sea-going ships for energy measurement and scientific research purposes. Contemporary sea-going ships are equipped as a rule with up-to-date measurement instrumentation usually based on electronic data processing and computer technique. These authors have made many times use of such instruments in their research work. This way it was not necessary to install any special instruments, that significantly reduced measurement cost. In such cases to obtain a sufficient accuracy of measurements constitutes a crucial problem. In this paper was presented an analysis of measurement errors of some operational parameters of ship and its main propulsion system, elaborated within the frame of the KBN research project no. 9 T12D 033 17. Results of the analysis confirm usefulness of the standard measurement instrumentation installed on ships, and its sufficient accuracy.
Manoeuvring forces on azimuthing podded propulsor model
Authors: Reichel Maciej
Published: May 2008

Manoeuvring forces on azimuthing podded propulsor model

This paper presents the preliminary part of comprehensive manoeuvring open-water tests of a gas carrier model. The paper focuses on open water experiments with an azimuthing podded propulsor. The test program was carried out in the cavitation tunnel and the large towing tank of Ship Hydromechanics Division, Ship Design and Research Centre, Gdańsk. The pod was tested as a pushing unit with a 161.3 mm diameter propeller. Steering forces were measured in the range of advance coefficient from 0.0 to 0.8 combined with the range of deflection angles from -45° up to +45°. Measurements on the pod without propeller were also performed. The experiment results are presented in the form of non-dimensional coefficients in function of advance coefficient and deflection angle. Analysis of the experimental results and the conclusions are presented.
On the fatigue-critical amplitude of random-amplitude stress
Authors: Kolenda Janusz
Published: May 2008

On the fatigue-critical amplitude of random-amplitude stress

Uniaxial non-zero mean stress of constant circular frequency in the high-cycle fatigue regime is considered. It is assumed that equation of the S-N curve and modified Soderberg equation are applicable. For constant-amplitude stress, the fatigue-critical stress amplitude is defined as that which leads to failure during the required design life. For random-amplitude stress, expected values of the fatigue-critical stress amplitude and total fatigue damage accumulated during the required design life are estimated. It is found that the probability of fatigue failure is equal to the probability of exceedance of the fatigue-critical stress amplitude. As an example, for stationary random stress the equivalent random-amplitude stress and probability of fatigue failure are determined.
Application of movable approximation and wavelet decomposition to smoothing-out procedure of ship engine indicator diagrams
Authors: Polanowski Stanisław
Published: May 2008

Application of movable approximation and wavelet decomposition to smoothing-out procedure of ship engine indicator diagrams

In this paper - on the basis of indicator diagram processing taken as an example - were shown possibilities of the smoothing-out and decomposing of run disturbances with the use of the movable multiple approximation based on the least squares criterion. The notion was defined of movable approximating object and constraints used to form approximation features. It was demonstrated that the multiple approximation can be used to decompose disturbances out of an analyzed run. The obtained smoothing-out results were compared with those obtained from full-interval approximation of runs by means of splines as well as wavelet decomposition with using various wavelets, Wavelet Explorer and Mathematica software. Smoothing-out quality was assessed by comparing runs of first derivatives which play crucial role in the advanced processing of indicator diagrams.
Calculation of the mean long-term service speed of transport ship: Part III Influence of shipping route and ship parameters on its service speed
Authors: Szelangiewicz Tadeusz , Żelazny Katarzyna
Published: May 2008

Calculation of the mean long-term service speed of transport ship: Part III Influence of shipping route and ship parameters on its service speed

Service speed obtainable by a ship in real weather conditions when sailing on a given shipping route, is one of the major parameters which have great impact on ship operation costs. The so far used, very approximate method of service speed prediction based on "service margin", is very little exact. In this paper a new method based on additional ship resistance dependent on mean statistical parameters of wave and wind occurring on a given shipping route, is presented. The mean long-term service speed is calculated on the basis of the calculated additional resistance and the screw propeller and propulsion engine parameters. Also, a new definition of service margin and a way of its calculation is presented apart from the results of the mean service speed calculation depending on ship's type and size and shipping route.
The catamarans George and Energa Solar
Authors: Duda Dariusz , Litwin Wojciech
Published: May 2008

The catamarans George and Energa Solar

Since a few years students of the Faculty of Ocean Engineering and Ship Technology, Gdansk University of Technology, have designed and built untypical floating units. Until last year their efforts were focused mainly on leg-driven boats. The boats of interesting design have taken part in yearly competitions: the International Waterbike Regatta. Their advanced design made it possible to compete with the best boats from Croatia, Holland, Germany, Turkey and Italy. Recently the students have designed and built a solar-energy-driven boat. It is the catamaran Energa Solar which took part in a prestigious regatta: the Frisian Nuon Solar Challenge carried out in Holland in summer 2006.
Dynamic interaction of the cavitating propeller tip vortex with the rudder
Authors: Szantyr Jan
Published: May 2008

Dynamic interaction of the cavitating propeller tip vortex with the rudder

The hydrodynamic interaction between the ship propeller and the rudder has many aspects. One of the most interesting is the interaction between the cavitating tip vortex shed from the propeller blades and the rudder. This interaction leads to strongly dynamic behaviour of the cavitating vortex, which in turn generates unusually high pressure pulses in its vicinity. Possibly accurate prediction of these pulses is one of the most important problems in the hydrodynamic design of a new ship. The paper presents a relatively simple computational model of the propeller cavitating tip vortex behaviour close to the rudder leading edge. The model is based on the traditional Rankine vortex and on the potential solution of the dynamics of the cylindrical sections of the cavitating kernel passing through the strongly variable pressure field in the vicinity of the rudder leading edge. The model reproduces numerically the experimentally observed process of initial compression of the vortex kernel in the high pressure region near the stagnation point at the rudder leading edge and subsequent explosive growth of the kernel in the low pressure region further downstream. Numerical simulation of this process enables computation of the additional pressure pulses generated due to this phenomenon and transmitted onto the hull surface. This new numerical model of the cavitating tip vortex is incorporated in the modified unsteady lifting surface program for prediction of propeller cavitation, which has been successfully used in the process of propeller design for several years and which recently has been extended to include the effects of propeller — rudder interaction. The results of calculations are compared with the experimental measurements and they demonstrate reasonable agreement between theory and physical reality.
The effect of blade thickness on microstructure and mechanical properties of ship's sand-cast propeller
Authors: Piaseczny Leszek , Rogowski Krzysztof
Published: May 2008

The effect of blade thickness on microstructure and mechanical properties of ship's sand-cast propeller

The microstructure and resultant mechanical properties of the MM55 manganese brass applied to ship sand - cast propeller were investigated in relation to the propeller blade section thickness. It was stated that the increase of blade section thickness from 15 mm to 45 mm resulted in the increase of the volume fraction of α-phase by 5.3% and that of κ-phase by 23.7%, the decrease of the volume fraction of α-phase by 2.9%, the 0.2% proof stress R0.2 by 11.3%, the ultimate tensile strength Rm by 5.5% and the 5.65 √Soelongation A5 by 16.8%.
Mean long-term service parameters of transport ship propulsion system: Part II Propulsion engine service parameters of transport ship sailing on a given shipping route
Authors: Szelangiewicz Tadeusz , Żelazny Katarzyna
Published: May 2008

Mean long-term service parameters of transport ship propulsion system: Part II Propulsion engine service parameters of transport ship sailing on a given shipping route

During ship sailing on a given shipping route in real weather conditions all propulsion system performance parameters of the ship change along with changes of instantaneous total resistance and speed of the ship. In this paper results of calculations are presented of distribution function and mean statistical values of screw propeller thrust, rotational speed and efficiency as well as propulsion engine power output and specific fuel oil consumption occurring on selected shipping routes. On this basis new guidelines for ship propulsion system design procedure are formulated.
Experimental research on effectiveness of the magnetic fluid seals for rotary shafts working in water
Authors: Szydło Zbigniew , Matuszewski Leszek
Published: May 2008

Experimental research on effectiveness of the magnetic fluid seals for rotary shafts working in water

This paper presents course of research on ferro-fluidal seals used in water. The tests were carried out for a hydrophobic magnetic fluid and specially selected profiles of sealing lips at various linear velocities in sealing unit. Though the tests were preliminary their results showed that the research on application of magnetic fluids to seals working in liquid environment should be continued. From the point of view of development of ring drives the most important advantage of ferro-fluidal seals is their smallest drag as compared with seals of other types.
Shooting resistance of non-metallic materials
Authors: Kyzioł Lesław
Published: May 2008

Shooting resistance of non-metallic materials

This paper presents test results of shooting resistance of non-metallic materials such as ceramics, rubber, glass reinforced plastic (GRP), natural and modified wood. It was demonstrated that GRP samples 16 mm thick protected with ceramic plates 10 mm thick can be considered bullet-proof against bullets of 7.62 mm caliber. And, multi-layer plate with a core of natural or modified wood cannot be taken as a bullet-proof material against 7.62 mm bullets.
Distribution of Word Classes in Old English and Old High German: a Preliminary Contrastive Study Based on „The Battle of Maldon”, „Hildebrandslied” and „Ludwigslied”
Authors: Kamińska Anna
Published: May 2008

This paper presents an example of a historical study based on comparable corpora. It aims to analyse and compare the distribution of different parts of speech in Old English and Old High German, thus providing a quantitative basis for further conclusions concerning different patterns of the development of those two West-Germanic languages. A particular attention has been devoted to the frequencies of prepositions and pronouns, as there are considerable differences between the languages in this respect. In addition, the article is a an attempt to show the importance and relevance of computational data for contrastive historical linguistics and their role in supporting or disproving traditional theories.
Understanding Language Death in Czech-Moravian Texas
Authors: Hannan Kevin
Published: May 2008

Based on several decades of personal interaction with Texas speakers of Czech, the author’s article attempts to correlate social change with some specific stages of language obsolescence and language death. Many instances of language change in that community, as well as cultural and social change, may be explained by the linguistic model known as the wave theory. One hundred and fifty years passed between the introduction of Czech and the death of that language in Texas. From the mid-nineteenth through the mid-twentieth century, the Czech-Moravians represented a closed community in which individuals defined their identity primarily by the Czech language, ethnicity, and culture. In the final five decades of the twentieth century, as the social template representing Texas speakers of Czech disintegrated, spoken Czech ceased to function as a living language, and much of the ancestral culture connected with the language was lost. Today some among the elderly, described as semi-speakers, terminal speakers, or ‘‘rememberers’’ of language, retain a limited knowledge, but the ancestral language now has only a symbolic function.
The Time Constraint in Conference Interpreting: Simultaneous vs. Consecutive
Authors: Gumul Ewa , Łyda Andrzej
Published: May 2008

The present paper focuses on the concept of time constraint in interpreting. The main aim of the study is to compare the two modes of interpreting, i.e. consecutive and simultaneous in terms of the temporal load imposed by the operations constituting each of them. The discussion centres on the issues of external pacing and processing capacity management, the two focal points of The Time Constraint. The paper also examines a range of strategies interpreters resort to in order to minimise the impact of time pressure in both CI and SI, such as EVS regulation, economy of expression, text-editing strategies, and notation techniques.
On Multiple Metonymies within Indirect Speech Acts
Authors: Kosecki Krzysztof
Published: May 2008

Indirect speech acts are frequently structured by more than a single metonymy. The metonymies are related not only to the illocutionary force of the utterances, but also function within the individual lexemes being their parts. An indirect speech act can thus involve not only multiple, but also multi-levelled operation of conceptual metonymy.
Words for Women’s Boots in Present-Day Polish: a Quantitative and Contrastive Onomasiological Study
Authors: Wilson Andrew
Published: May 2008

Footwear terminology demonstrates interesting cross-linguistic differences and is, consequently, also a problematic area for non-native speakers. In order to arrive at a more accurate picture of a subset of footwear terminology in present-day Polish, 82 native speakers were asked to name a range of six contemporary women’s boot styles. No style showed a complete agreement in the preferred head noun, although a clear trend was evident for each one, with kozaki being the most commonly used overall. The possibly uniquely Polish use of a military metaphor for tall riding-style boots (oficerki) and the special subcultural case of Dr. Martens-style boots are discussed in particular. The choice of modifiers within noun phrases for boots is also examined. Some contrastive data are presented from speakers of Greek and Russian.