bluuebunny/crossref_metadata_2025 huggingface dataset:
Cytogenetic characteristics of species of the Chironomus genus (Diptera, Chironomidae) from Lake Łuknajno Biosphere Reserve (northwest Poland)
Authors: Jabłońska-Barna Izabela , Michailova Paraskeva
Published: June 2009

The cytotaxonomic characteristics of two species of the Chironomus genus from Lake Łuknajno (northwest Poland) were determined: Chironomus nuditarsis Strenzke, 1959 with the chromosome arm combinations of AB, CD, EF, and G (the "thummi" cytocomplex), and Camptochironomus tentans (Fabricius, 1805) with the chromosome arm combinations of AB, CF, DE, and G. A heterozygous inversion in arm F of the Chironomus nuditarsis chromosomes was detected. The polymorphism of Camptochironomus tentans as a homozygous inversion in arms A and E and a heterozygous inversion in arm F were revealed.
Chironomidae (Diptera) community response to improved oxygen conditions in a naturally recovering lake (Łękuk Wielki, northeast Poland)
Authors: Koszałka Jacek
Published: June 2009

A Study of the chironomid community was undertaken in Lake Łękuk Wielki during the 1997-1999 period. Twenty six taxon belonging to the subfamilies Tanypodinae and Chironomini were identified. Taxonomic diversity decreased with increasing depth in the lake, but the occurrence of Chironomidae larvae was noted even in the deepest part of the lake. Chironomidae clearly indicated that Lake Łękuk Wielki is recovering.
Catalysts on Demand: Selective Oxidations by Laboratory-Evolved Cytochrome P450 BM3
Authors: Lewis Jared C. , Arnold Frances H.
Published: June 2009

Efficient catalysts for selective oxidation of C–H bonds using atmospheric oxygen are highly desirable to decrease the economic and environmental costs associated with conventional oxidation processes. We have used methods of directed evolution to generate variants of bacterial
cytochrome P450 BM3 that catalyze hydroxylation and epoxidation of a wide range of nonnative substrates. This fatty acid hydroxylase was converted to a propane monooxygenase (PMO) capable of hydroxylating propane at rates comparable to that of BM3 on its natural substrates. Variants along
the PMO evolutionary lineage showed broadened substrate scope; these became the starting points for evolution of a wide array of enzymes that can hydroxylate and derivatize organic scaffolds. This work demonstrates how a single member of enzyme family is readily converted by evolution into
a whole family of catalysts for organic synthesis.
Evolutionary Cycles for Pericyclic Reactions – Or Why We Keep Mutating Mutases
Authors: Roderer Kathrin , Kast Peter
Published: June 2009

Directed evolution strategies are being applied ever more frequently to develop novel and improved enzymes for many applications, including those contributing to 'white biotechnology'. In addition to engineering new biocatalysts, evolutionary strategies are equally suited to the elucidation
of enzyme structure and function. Here, we illustrate with selected examples from our own work on chorismate mutases how such strategies can be employed to address a range of fundamental questions. Over the last decade, this model system, which was once considered to be a 'very simple' enzyme
from the shikimate pathway, has afforded many – sometimes surprising – discoveries about biocatalysis. It has also taught us how to upgrade evolutionary approaches to overcome technical hurdles. Both the new insights and the methodological improvements should enhance our ability
to tailor enzymes for novel uses.
Lonza: Biotechnology – A Key Ingredient for Success in the Future
Authors: Robins Karen T. , Osorio-Lozada Antonio , Avi Manuela , Meyer Hans-Peter
Published: June 2009

Lonza began as a small Swiss electricity company and it has successfully adapted to change throughout its history to become a global custom manufacturing company serving the needs of the life-science industry. One of the crucial decisions and changes in its development was the implementation
of biotechnology. This article outlines briefly the history of change during Lonza's development, some of the problems that confronted the chemical industry approximately a decade ago and how they affected the area of biotransformation. There are still many chemical reactions that are difficult,
inefficient and environmentally unfriendly. Lonza believes that some of these problems can be solved by biotechnology if the biocatalytic platform can be widened and improved so that the biocatalysts can be easily integrated into a chemical process.
Enzymatic C–C-Coupling Prenylation: Bioinformatics – Modelling – Mechanism – Protein-Redesign – Biocatalytic Application
Authors: Wessjohann Ludger , Zakharova Svetlana , Schulze Diana , Kufka Julia , Weber Roman , Bräuer Lars , Brandt Wolfgang
Published: June 2009

The functional role of isoprenoids and especially enzymatic prenylation in nature and human application is briefly covered, with the focus on bioinformatical, mechanistical and structural aspects of prenyltransferases and terpene synthases. These enzymes are as yet underrepresented
but perspectively useful biocatalysts for C–C couplings of aromatic and isoprenoid substrates. Some examples of the successful use in chemoenzymatic synthesis are given including an application for the otherwise difficult synthesis of Kuhistanol A. Computational structure-based site-directed
mutagenesis can be used for rational enzyme redesign to obtain altered substrate and product specificities, which is demonstrated for terpene cyclases.
Marker-free cell discrimination by holographic optical tweezers
Authors: Schaal F. , Warber M. , Zwick S. , van der Kuip H. , Haist T. , Osten W.
Published: June 2009

We introduce a method for marker-free cell discrimination based on optical tweezers. Cancerous, non-cancerous, and drug-treated cells could be distinguished by measuring the trapping forces using holographic optical tweezers. We present trapping force measurements on different cell lines: normal pre-B lymphocyte cells (BaF3; “normal cells”), their Bcr-Abl transformed counterparts (BaF3-p185; “cancer cells”) as a model for chronic myeloid leukaemia (CML) and Imatinib treated BaF3-p185 cells. The results are compared with reference measurements obtained by a commercial flow cytometry system.
Tuning optical properties of opal photonic crystals by structural defects engineering
Authors: Di Stasio F. , Cucini M. , Berti L. , Comoretto D. , Abbotto A. , Bellotto L. , Manfredi N. , Marinzi C.
Published: June 2009

We report on the preparation and optical characterization of three dimensional colloidal photonic crystal (PhC) containing an engineered planar defect embedding photoactive push-pull dyes. Free standing polystyrene films having thickness between 0.6 and 3 µm doped with different dipolar chromophores were prepared. These films were sandwiched between two artificial opals creating a PhC structure with planar defect. The system was characterized by reflectance at normal incidence angle (R), variable angle transmittance (T) and photoluminescence spectroscopy (PL) Evidence of defect states were observed in T and R spectra which allow the light to propagate for selected frequencies within the pseudogap (stop band).
PATH DEPENDENCE, DEVELOPMENT, AND THE DYNAMICS OF INSTITUTIONAL REFORM
Authors: Prado Mariana , Trebilcock Michael
Published: June 2009

In the past decade, an institutional perspective on development has become increasingly prominent in development thinking. However, the reform experience thus far suggests that if institutions indeed matter for development, we still do not have a firm understanding of how to transforms dysfunctional institutions. Drawing on concrete examples of rule of law and property rights reforms, we argue that path dependence theory can shed some light on past failures and provide guidance for future reforms.
Effects of Oral Estrogen on Aortic ROS-Generating and -Scavenging Enzymes and Atherosclerosis in apoE-Deficient Mice
Authors: Wing Lih-Yuh Chen , Chen Ya-Chi , Shih Yu-Yin , Cheng Jung-Chien , Lin Yiu-Jiuan , Jiang Meei Jyh
Published: June 2009

The effect of hormone replacement therapy (HRT) on cardiovascular diseases remains controversial. Studies conducted on postmenopausal women indicate that oral HRT increases risk factors that may counteract the atheroprotective effect of estrogen. However, the effects of estrogen on atherosclerosis have been examined using subcutaneous estrogen in most animal studies, which points to the need for evaluating the effect of oral estrogen. Reactive oxygen species (ROS) have emerged as critical factors in the pathogenesis of atherosclerosis. This study examined the effect of long-term oral estrogen treatment on aortic oxidative stress and atherosclerosis in female apoE−/− mice to mimic HRT in humans. Ovariectomized apoE−/− mice were given 6 μg/day of oral 17β-estradiol (E2) or control vehicle for 12 weeks. Estrogen treatment reduced atherosclerotic lesions by 38% (E2: 0.20 ± 0.01 mm2/section; control vehicle: 0.32 ± 0.02 mm2/section) and intima by 32% (E2: 0.44 ± 0.02 mm2/section; control vehicle: 0.65 ± 0.04 mm2/section) in the aortic root. Serum levels of total and low-density lipoprotein cholesterol were significantly decreased after estrogen treatment. Aortic superoxide anion levels and the expression of NAD(P)H oxidase subunit p22phox markedly decreased, and two ROS scavenging enzymes, Cu/ZnSOD and MnSOD, were upregulated after estrogen treatment. Estrogen at physiological concentration inhibited tumor necrosis factor-α-stimulated NAD(P)H oxidase activity in both cultured smooth muscle cells and peritoneal macrophages. These results showed that long-term oral estrogen treatment reduces ROS levels and atherosclerosis progression in apoE−/− mice. Oral estrogen alters ROS-generating and -scavenging enzyme expression, suggesting that anti-oxidative actions in the vessel wall contribute to atheroprotective effects of estrogen.
Lanthanum Acetate Inhibits Vascular Calcification Induced by Vitamin D3 Plus Nicotine in Rats
Authors: Zhou Ye-Bo , Jin Shao-Ju , Cai Yan , Teng Xu , Chen Li , Tang Chao-Shu , Qi Yong-Fen
Published: June 2009

Lanthanum, a rare earth element, has been used to decrease serum phosphorus level in patients with chronic renal disease and hyperphosphatemia. We aimed to observe the effect and mechanism of two doses of lanthanum acetate (375 and 750 mg/kg/day) on vascular calcification induced by vitamin D3 plus nicotine treatment in rats for 4 weeks. As compared with control rats, rats with calcification showed widespread calcified nodules and irregular elastic fibers in calcified aorta on von Kossa calcium staining and increased aortic calcium and phosphorus contents, alkaline phosphatase (ALP) activity and bone-related protein expressions for osteopontin (OPN) and type III sodium dependent phosphate cotransporter Pit-1 (Pit-1). After treatment with either dose of lanthanum acetate, the calcified nodules and degree of irregular elastic fibers decreased in aortas. Lanthanum acetate at 750 mg/kg/day was more effective than 375 mg/kg/day in lessening vascular calcification by significantly reducing plasma phosphorus level, calcium × phosphorus product and ALP activity, by 30.3%, 28.6%, and 68.6%, respectively; reducing aortic phosphorus and calcium contents and ALP activity, by 48%, 53.1%, and 63.5% (all P < 0.01), respectively; reducing aortic mRNA level of OPN and Pit-1, by 55.8% ( P < 0.01) and 38.8% ( P < 0.05) and protein level of OPN and Pit-1, by 37.2% and 27.2% (both P < 0.01), respectively; and increasing carboxylated matrix Gla-protein (MGP) protein expression by 33.7% ( P < 0.05), as compared with rats treated with vitamin D3 and nicotine alone. Lanthanum acetate could effectively inhibit the pathogenesis of vascular calcification.
Gender Differences in Cardiac Ischemic Injury and Protection—Experimental Aspects
Authors: Ostadal Bohuslav , Netuka Ivan , Maly Jiri , Besik Josef , Ostadalova Ivana
Published: June 2009

This review summarizes some available information on gender differences of myocardial injury with particular attention to experimental approach. It has been observed that significant gender differences exist already in normal heart. They involve among others cardiac growth, contractile function, calcium metabolism and function of mitochondria. Differences, characteristic of the normal myocardium, generate the logical presumption of the different reaction of the male and female heart to various pathogenic factors. Most of the experimental studies confirm the clinical observations: increased resistance of the female heart to ischemia/reperfusion injury was shown in dogs, rats, mice and rabbits. Furthermore, gender differences in the ischemic tolerance of the adult myocardium can be influenced by interventions (e.g. hypoxia) imposed during the early phases of ontogenetic development. The already high tolerance of the adult female heart can be increased by adaptation to chronic hypoxia and ischemic preconditioning. It seems that the protective effect depends on age: it was absent in young, highly tolerant heart but it appeared with the decrease of natural resistance during aging. Both experimental and clinical studies have indicated that female gender influences favorably also the remodeling and the adaptive response to myocardial infarction. It follows from the data available that male and female heart differs significantly in many parameters under both physiological and pathological conditions. Detailed molecular and cellular mechanisms of these differences are still unknown; they involve genomic and non-genomic effects of sex steroid hormones, particularly the most frequently studied estrogens. The cardiovascular system is, however, influenced not only by estrogens but also by other sex hormones, e.g. androgens. Moreover, steroid hormone receptors do not act alone but interact with a broad array of co-regulatory proteins to alter transcription. The differences are so important that they deserve serious consideration in clinical practice in search for proper diagnostic and therapeutic procedures.
RPC6 Up-Regulation in Ang II-Induced Podocyte Apoptosis Might Result from ERK Activation and NF-κB Translocation
Authors: Zhang Han , Ding Jie , Fan Qingfeng , Liu Shufang
Published: June 2009

Angiotensin II (Ang II) has been recognized as an apoptosis inducer in podocytes, but the mechanism of apoptosis induced by Ang II is unclear. Transient receptor potential cation channel 6 (TRPC6) is a calcium channel located in podocyte membrane. The present study evaluated the alteration of TRPC6 expression and the Ca2+influx involved in Ang II-induced podocyte apoptosis. The possible pathways related to TRPC6 in Ang II-induced podocyte apoptosis were also investigated. The apoptosis of mouse podocytes (MPC5) was induced by Ang II. The protein level of TRPC6 was increased markedly in response to Ang II stimulation, and the intracellular Ca2+concentration was elevated. By transfection with TRPC6 siRNA, Ang II-induced podocyte apoptosis and the transient Ca2+influx were inhibited. Treated with extracellular signal-regulated kinase (ERK) pathway specific inhibitor U0126 or nuclear factor-κB (NF-κB) pathway specific inhibitor ammonium pyrrolidinedithiocarbamate (PDTC) and Ang II, respectively in podocytes, not only was the TRPC6 up-regulation reduced, but the podocyte apoptosis was also decreased. Moreover, the translocation of NF-κB in nucleus resulted from Ang II was reduced by treatment with U0126. In conclusion, the enhancement expression of TRPC6 as well as the increased Ca2+influx mediated by TRPC6 channels contributed to the podocyte apoptosis. The activation of ERK pathway and subsequent translocation of NF-κB was possibly necessary for the up-regulation TRPC6 induced by Ang II.
Increased Engraftment of Hepatic Progenitors After Activation of the Hepatocyte Growth Factor Signaling Pathway by Protein Transduction
Authors: Kellermann Guillaume , Boudechiche Lyes , Weber Anne , Hadchouel Michelle
Published: June 2009

Cell transplantation has become a major focus in biomedical research. However, efficient engraftment in solid tissues remains a challenge. Hepatocyte growth factor (HGF) signaling increases survival, proliferation, migration, and invasion of many cell types through Met, its cell surface receptor. Therefore, activation of this signaling pathway may improve the ability of many cells to be transplanted. We constructed a constitutively activated form of Met (Tpr-Met) fused to the protein transduction domain of HIV-TAT to activate the HGF/Met pathway for a few hours following cell injection. Matrix-assisted refolding was used to renature TAT-Tpr-Met protein, which was efficiently delivered into cells and recapitulated several biological functions of Met in vitro. Furthermore, treatment of hepatic progenitors with this molecule for one hour before transplantation significantly improved engraftment efficiency (31% untreated cells, 58% treated cells). These findings suggest that the transient transfer of Tpr-Met may provide a new approach to increase the proportion of successfully engrafted cells.
Sphingolipids as Determinants of Apoptosis and Chemoresistance in the MCF-7 Cell Model System
Authors: Meacham William D. , Antoon James W. , Burow Matthew E. , Struckhoff Amanda P. , Beckman Barbara S.
Published: June 2009

An estimated 182,640 women and 1,990 men were diagnosed with breast cancer in 2008, and approximately 40,480 women and 450 men died from the disease ( 1 ). Thus, continued mechanistic studies are needed to understand the causes and develop additional therapeutics for this complicated disease. The MCF-7 cell system is one of the most recognized models for estrogen receptor (ER)-positive breast cancer and has generated ~13,000 publications cited in PubMed to date. A number of clues for biological mechanisms related to apoptotic/anti-apoptotic pathways and chemoresistance were elucidated and summarized in our previous review ( 2 ). The focus of this review is new knowledge of the central role of sphingolipid signaling in apoptotic mechanisms in estrogen receptor-positive breast cancer. The ultimate goal is to target crucial steps in survival signaling pathways that may ultimately provide additional translational solutions to the successful pharmacologic treatment of breast cancer.
Mitochondrial Nitric Oxide Synthase: A Masterpiece of Metabolic Adaptation, Cell Growth, Transformation, and Death
Authors: Finocchietto Paola V. , Franco Maria C. , Holod Silvia , Gonzalez Analia S. , Converso Daniela P. , Arciuch Valeria G. Antico , Serra Maria P. , Poderoso Juan J. , Carreras Maria C.
Published: June 2009

Mitochondria are specialized organelles that control energy metabolism and also activate a multiplicity of pathways that modulate cell proliferation and mitochondrial biogenesis or, conversely, promote cell arrest and programmed cell death by a limited number of oxidative or nitrative reactions. Nitric oxide (NO) regulates oxygen uptake by reversible inhibition of cytochrome oxidase and the production of superoxide anion from the mitochondrial electron transfer chain. In this sense, NO produced by mtNOS will set the oxygen uptake level and contribute to oxidation-reduction reaction (redox)–dependent cell signaling. Modulation of translocation and activation of neuronal nitric oxide synthase (mtNOS activity) under different physiologic or pathologic conditions represents an adaptive response properly modulated to adjust mitochondria to different cell challenges.
Genetic Variations in the Hypoxia-Inducible Factor-1αGene and Lung Cancer
Authors: Konac Ece , Dogan Irem , Onen Hacer Ilke , Yurdakul Ahmet Selim , Ozturk Can , Varol Ayhan , Ekmecki Abdullah
Published: June 2009

Hypoxia-inducible factor-1 ( HIF-1), an important genetic component of angiogenesis, becomes stable as a response to tumor hypoxia and facilitates tumor survival. The polymorphisms of the HIF-1αgene may cause changes in the activity of this protein, which serves as a transcription factor for many genes in tumorigenesis. In this study, we have investigated the relationship between seven HIF-1αpolymorphisms [C > T substitution in intron 8 (rs10873142), T418I (rs41508050) in exon 10, P564P (rs41492849), L580L (rs34005929), P582S (rs11549465), A588T (rs11549467) in exon 12 and dinucleotide GT repeats in intron 13 (rs10645014)] among lung cancer patients in the Turkish population. Genomic DNA was isolated from 141 lung cancer cases and 156 controls and subjected to PCR for amplification. Genotyping was carried out with RFLP and DNA sequencing methods. There was no significant difference between the lung cancer cases and controls in terms of the distribution of genotyping frequencies of seven HIF-1αpolymorphisms ( P > 0.05). No significant relationship was found between the C > T substitution in intron 8 and P582S haplotypes and development of lung cancer. In addition, there were no significant associations between the genotypes and clinopathological characteristics of the cases examined. These findings show that polymorphisms in the HIF-1αgene do not confer susceptibility to lung cancer. Exp Biol Med 234:1109–1116, 2009
Regulation of Glucose Uptake in Mesangial Cells Stimulated by High Glucose: Role of Angiotensin II and Insulin
Authors: Arnoni Carine P. , Lima Carla , Cristovam Priscila C. , Maquigussa Edgar , Vidotti Daniela B. , Boim Mirian A.
Published: June 2009

Mesangial cells (MCs) play a central role in the pathogenesis of diabetic nephropathy (DN). MC dysfunction arises from excessive glucose uptake through insulin-independent glucose transporter (GLUT1). The role of the insulin-dependent transporter (GLUT4) remains unknown. This study evaluated the effect of high glucose on GLUT1, GLUT4, and fibronectin expression levels. Glucose uptake was determined in the absence and presence of insulin. Angiotensin II has been implicated as a mediator of MC abnormalities in DN, and its effects on the GLUTs expression were evaluated in the presence of losartan. MCs were exposed to normal (NG, 10 m M) or high (HG, 30 m M) glucose for 1, 4, 12, 24, and 72 hrs. Glucose uptake was elevated from 1 hr up to 24 hrs of HG, but returned to NG levels after 72 hrs. HG induced an early (1-, 4-, and 12-hrs) rise in GLUT1 expression, returning to NG levels after 72 hrs, whereas GLUT4 was overexpressed at later timepoints (24 and 72 hrs). HG during 4 hrs induced a 40% rise in glucose uptake, which was unaffected by insulin. In contrast, after 72 hrs, glucose uptake was increased by 50%, only under insulin stimulus. Losartan blunted the effects of HG on GLUT1, GLUT4, and fibronectin expression and on glucose uptake. Results suggest that MCs can be highly susceptible to the HG environment since they uptake glucose in both an insulin-independent and insulin-dependent manner. The beneficial effects of angiotensin II inhibition in DN may also involve a decrease in the rate of glucose uptake by MCs.
Composition and origin of amber ice and its influence on the behaviour of cold glaciers in the McMurdo Dry Valleys, Antarctica
Authors: Mager Sarah , Fitzsimons Sean , Frew Russell , Samyn Denis , Lorrain Reginald
Published: June 2009

This paper examines the basal ice sequence of Rhone Glacier, a cold-based glacier in the McMurdo Dry Valleys, Antarctica, using isotopic and solute chemistry data. Three different ice facies are identified: englacial, amber and stratified. The englacial facies is clean, bubbly ice of meteoric origin and is underlain by an amber facies. Amber ice is a characteristic of cold alpine glaciers in the McMurdo Dry Valleys and is distinctive for its high solute concentrations and much higher strain rates compared with the overlying englacial ice and the underlying stratified ice. Analysis of the stratified facies reveals an isotopic signature indicative of melt then refreeze processes and it is most likely associated with apron entrainment at the margin. By contrast, the amber facies has a co-isotopic slope of 8 and plots on a meteoric waterline. The inclusion of impurities in the amber ice reveals prolonged contact with the bed, and its depleted isotopic signature is consistent with ice formed during a cooler period. Comparison of the basal sequence of Rhone Glacier with other cold-based glaciers in the McMurdo Dry Valleys reveals strong similarities between valley-side glaciers (e.g. Meserve and Rhone Glaciers), whereas valley-floor glacier basal sequences (e.g. Suess Glacier) are characterized by structurally complex amalgamations of ice and debris.
Basal conditions for Pine Island and Thwaites Glaciers, West Antarctica, determined using satellite and airborne data
Authors: Joughin Ian , Tulaczyk Slawek , Bamber Jonathan L. , Blankenship Don , Holt John W. , Scambos Ted , Vaughan David G.
Published: June 2009

We use models constrained by remotely sensed data from Pine Island and Thwaites Glaciers, West Antarctica, to infer basal properties that are difficult to observe directly. The results indicate strong basal melting in areas upstream of the grounding lines of both glaciers, where the ice flow is fast and the basal shear stress is large. Farther inland, we find that both glaciers have ‘mixed’ bed conditions, with extensive areas of both bedrock and weak till. In particular, there are weak areas along much of Pine Island Glacier’s main trunk that could prove unstable if it retreats past the band of strong bed just above its current grounding line. In agreement with earlier studies, our forward ice-stream model shows a strong sensitivity to small perturbations in the grounding line position. These results also reveal a large sensitivity to the assumed bed (sliding or deforming) model, with non-linear sliding laws producing substantially greater dynamic response than earlier simulations that assume a linear-viscous till rheology. Finally, comparison indicates that our results using a plastic bed are compatible with the limited observational constraints and theoretical work that suggests an upper bound exists on maximum basal shear stress.
Measured shear rates in large dry and wet snow avalanches
Authors: Kern Martin , Bartelt Perry , Sovilla Betty , Buser Othmar
Published: June 2009

We present estimates of internal shear rates of real-scale avalanches that are based on velocity measurements. Optical velocity sensors installed on the instrument pylon at the Swiss Vallée de la Sionne test site are used to measure flow velocities at different flow heights of three large dry and wet snow avalanches. Possible sources of error in the correlation analysis of the time-lagged reflectivity signals measured by optical sensors are identified for real-size avalanches. These include spurious velocities due to noise and elongated peaks. An appropriate choice of the correlation length is essential for obtaining good velocity estimates. Placing restrictions on the maximum possible accelerations in the flow improves the analysis of the measured data. Coherent signals are found only in the dense flowing cores. We observe the evolution of shear rates at different depths between the front and tail of the flowing avalanche. At the front, large shear rates are found throughout the depth; at the tail, plug flows overriding highly sheared layers near the bottom of the flow are observed. The measured velocities change strongly with height above the ground and fluctuations around the measured mean velocity can be identified. We find that the dense flows are laminar, undergoing a transition from supercritical to subcritical flow behaviour from the head to the tail. Furthermore, we provide real-scale experimental evidence that the mean shear rate and the magnitude of velocity fluctuations increase with the mean discharge.
Age–depth correlation, grain growth and dislocation-density evolution, for three ice cores
Authors: Morland L.W.
Published: June 2009

Two previous theoretical analyses of data from the GRIP, Vostok and Byrd ice cores, presenting age–depth correlations, grain growth and dislocation-density evolution, are re-examined. It is found that the age–depth correlations are inconsistent with the idealized flow with unchanging history adopted, but that good correlations can be obtained by relaxing those restrictions. A modified grain-growth relation is proposed, consistent with the distinct growth profiles of the Vostok and other two cores, which can be solved simultaneously with the given dislocation-density evolution equation. These are solved for all three cores with the given parameters, and the depth profiles of grain diameter and dislocation density at the present time are determined with the new age–depth correlation and with that shown empirically in the papers. The varying flow history influences the age–depth correlation, and hence the depth profiles, which is important both for the interpretation of core data, and for the determination of constitutive variables at each depth at the present time.
Estimation of glacier runoff and future trends in the Yangtze River source region, China
Authors: Shiyin Liu , Yong Zhang , Yingsong Zhang , Yongjian Ding
Published: June 2009

Glacier runoff from the Yangtze River source region (YRSR), China, is estimated for the period 1961–2000 using a degree-day approach. In the investigation area, glacier runoff accounts for 11.0% of the total river runoff during the period 1961–2000. In the 1990s its contribution to river runoff rises to 17.0%. Due to the current rate of glacier decline, the impact of glacier runoff on river runoff has recently increased in the source region. Based on two different climate-change scenarios derived from ECHAM5/MPI-OM, future glacier runoff is assessed for the period 2001–50. In all climate-change scenarios, annual glacier runoff shows a significant increase due to intensified ice melting. There is an increase in glacier runoff during spring and early summer, yet a significant decrease in late summer. This study highlights the current and future impact of glacier runoff on river runoff in the YRSR.
A cut-and-closure origin for englacial conduits in uncrevassed regions of polythermal glaciers
Authors: Gulley J.D. , Benn D.I. , Müller D. , Luckman A.
Published: June 2009

On uncrevassed regions of polythermal glaciers, englacial conduits can form by incision of supraglacial stream channels followed by roof closure. The origin and evolution of examples in Longyearbreen, Svalbard, and Khumbu Glacier, Nepal, were determined by speleological survey. The development of perennial incised channels requires that incision is significantly faster than glacier surface ablation, and thus will be favoured by high meltwater discharges in combination with cool climatic conditions or thick debris cover. Incised canyons can become blocked by drifted winter snow, refrozen meltwater, ice rafting from non-local sources (allochthonous breccias) and roof collapses (autochthonous breccias). Conduit closure can also occur in response to ice creep, particularly at depth. Following isolation from the surface, englacial conduits continue to evolve by vadose incision down to local base level. In the case of Longyearbreen, incision allowed the channel to reach the glacier bed, but on Khumbu Glacier deep incision is prevented because an effectively impermeable terminal moraine provides a high base level for the glacier drainage system. During our period of observations, deeper parts of the Longyearbreen conduit became blocked by a combination of ice accumulation and creep, causing the stream course to be re-routed to higher levels. On that glacier, incision, blockage and upward re-routing are cyclic. We conclude that ‘cut and closure’ is the dominant mechanism of englacial conduit formation on uncrevassed regions of polythermal glaciers.
Mass balance, flow and subglacial processes of a modelled Younger Dryas ice cap in Scotland
Authors: Golledge Nicholas R. , Hubbard Alun L. , Sugden David E.
Published: June 2009

We use an empirically validated high-resolution three-dimensional ice-sheet model to investigate the mass-balance regime, flow mechanisms and subglacial characteristics of a simulated Younger Dryas Stadial ice cap in Scotland, and compare the resulting model forecasts with geological evidence. Input data for the model are basal topography, a temperature forcing derived from GRIP δ18O fluctuations and a precipitation distribution interpolated from modern data. The model employs a positive-degree-day scheme to calculate net mass balance within a domain of 112500 km2, which, under the imposed climate, gives rise to an elongate ice cap along the axis of the western Scottish Highlands. At its maximum, the ice cap is dynamically and thermally zoned, reflecting topographic and climatic controls, respectively. In order to link these palaeoglaciological conditions to geological interpretations, we calculate the relative balance between sliding and creep within the simulated ice cap, forecast areas of the ice cap with the greatest capacity for basal erosion and predict the likely pattern of subglacial drainage. We conclude that ice flow in central areas of the ice cap is largely due to internal deformation, and is associated with geological evidence of landscape preservation. Conversely, the distribution of streamlined landforms is linked to faster-flowing ice whose velocity is predominantly the result of basal sliding. The geometry of the main ice mass focuses subglacial erosion in the mid-sections of topographic troughs, and produces glaciohydraulic gradients that favour subglacial drainage through low-order arterial routes.
Comparison of density cutters for snow profile observations
Authors: Conger Steven M. , McClung David M.
Published: June 2009

An investigation was made to estimate the variance, measurement errors and sampling error in currently accepted practices for manual snow density measurement carried out as part of snow profile observations using the available variety of density cutters. A field experiment in dry snow conditions was conducted using a randomized block design to account for layer spatial variability. Cutter types included a 500 cm3 aluminium tube, 200 and 100 cm3 stainless-steel box types, 200 cm3 stainless-steel wedge types and a 100 cm3 stainless-steel tube. Without accounting for variation due to weighing devices, the range of values for ‘accepted practice’ determined in this study included variation within individual cutters of 0.8–6.2%, variation between cutters of 3–12%, variation between cutter means and layer means of 2–7%, and under-sampling errors of 0–2%. The results of a statistical analysis suggest that snow density measurements taken using various density cutters are significantly different from each other. Without adjustment for under-sampling, and given that the mean of all measurements is the accepted true value of the layer density, variation exclusively between cutter types provides ‘accepted practice’ measurements that are within 11% of the true density.
Bacon's Ideas in his Essays: A Study from the Perspective of Islam
Authors: Kabir Mohammad Humayun
Published: June 2009

The paper aims at examining Francis Baconâs ideas in his Essays from the point of view of Islam. Taking some representative essays of Francis Bacon, I have tried to find out those ideas in these essays which are conflicting with Islamic ideas. Here I have also identified some baseless statements of bacon about our Prophet Mohammad (SM) and the Muslim ummah and Baconâs allegation against Hazrat Mohammad (SM) has also been refuted. A threadbare analysis of Baconâs ideas as revealed in the Essays has been done in the light of the Holy Quran. Here it is also discussed how Baconian ideas are harmful to mankind and for human civilization in general.doi: IIUC Studies Vol.2 2004
Employee-Employer Perception towards Healthcare Scheme for Employees of Business Enterprises in Bangladesh: An Empirical Study
Authors: Uddin Mohammed Asraf , Alam Mohammad Mofidul , Hossain Shahadat
Published: June 2009

There is an increasing need for the management of the large and medium scale businesses to provide health care schemes for their employees as people in all areas as well as commercial area are becoming more health conscious. This study firstly aims at understanding the present status of health care facilities available at the workplace from the viewpoint of both employees and employers. The study then asked the respondents whether a health care scheme is feasible in their organizations and how could they benefit from the health care scheme. Some actions have been suggested in terms of the overall findings that were revealed in the study. Finally the prospect of such health care scheme has been evaluated to understand how far would employers go in keeping their workers happy for ensuring health care for this vulnerable sector. Doi: IIUC Studies Vol.2 2004
Ambivalence: The Divided Self in Sylvia Plath's Poetry
Authors: Sharif Mohd Yasin
Published: June 2009

Ambivalence, mixed good and bad feelings about particular entity, individual or circumstance, became a ruling passion in Sylvia Plath's life. These ambivalence and breakdown are closely dealt with in her poems. Confessional poets usually reveal their own personal experiences without straining excruciating sentiment. Sylvia Plath, one of the 1960s most influential confessional poets used the same resentment and anguish that developed from her personal grief as the subject of many of her poems. SP is well known among the celebrities for her ambivalence schizophrenic, schizoid and paranoid nature. As an obsessive-compulsive neurotic, ambivalence dominated both her works as well as her life. This ambivalent personality of SP made her and her works obscure and bizarre to the readers. Many of her poems bear the evidence of narcissism, self-hatred, deep attachment and simultaneously deep hatred towards her dear and near ones. The present study is an endeavor to interpret this complex ambivalent personality of SP in light of her poems, her journals and her letters where she clearly confesses all her neurotic obsessed activities directly, honestly and sincerely without any hesitation. The study will also dug out the true logical reasons that lead to the suicide of a blooming star in her make up.   doi: 10.3329/iiucs.v3i0.2628 IIUC STUDIES Vol. - 3, December 2006 (p 7-18)
The Woman Question in the novels by the Bronte Sisters
Authors: Anis Rehnuma Bint
Published: June 2009

The Victorian period lasted more than half a century. During this time England changed radically in almost all respects. One of these was the rising consciousness of women about their rights and potentials. Soon, the social awareness was transmitted to literature. In retrospect we find that many women writers emerged at this critical juncture in history when women were pleading to be given voice, to achieve their rights and to be given an opportunity to come out of the shells of quiet submission enforced upon them and achieve something of their own. Three sisters living deep in the Yorkshire moors surprised the world by taking part in this ongoing struggle. This article attempts to evaluate their contributions towards achieving women's rights in English history.     doi: 10.3329/iiucs.v3i0.2629   IIUC STUDIES Vol. - 3, December 2006 (p 19-30)
'Frailty, Thy Name is Woman' - How Frail are Women in the World of Shakespeare?
Authors: Rahman Muhammad Safiur
Published: June 2009

This paper attempts to understand a remarkable point whether we can argue, quoting Hamlet's remark ‘frailty, thy name is woman', that Shakespeare is a misogynist. With that end in view it analyses the situations which lead Hamlet to hold a special kind of prejudice against women. Hence, it examines the justification of his misogynistic remarks in the play. Here the chief concern is whether it is Shakespeare's viewpoint or the view of his character Hamlet; and whether it is deep-rooted, well-thought one or momentary one. Some women characters in several other plays of Shakespeare have been studied, in an endeavor to compare their roles, and to see whether they all show weakness, or some of them surpass the male characters around them in their respective plays. The focus has always been simply on the point whether women are generally frail in the world of Shakespeare. The paper concludes that Hamlet's view does not represent the general view of women in Shakespearean literature; rather it is a sweeping generalization of the misogyny of a young man who has, somehow, been betrayed by women in his life.   doi: 10.3329/iiucs.v3i0.2630   IIUC STUDIES Vol. - 3, December 2006 (p 31-44)
The Use of Geometric Conceits in Exposition of Love in Metaphysical Poetry
Authors: Uddin Md Eftekhar
Published: June 2009

The language, used by Metaphysical poets is highly evocative and infused with multi-dimensional meaning. It demands comprehension and sensitivity on the part of the reader to grasp out the inner aspect of a poem. Love, being a universal feeling gets expression through the hands of different poets in different ways. The exposition of love in Metaphysical poems has shaped up in a unique way because of the juxtaposition of geometry in it. Straight line and circular line are the two components of geometry. Straight line being regarded as imperfect one as it has no limit and end is used as a vehicle to convey the imperfection of love in Metaphysical poems. On the other hand, circular line, being treated as a perfect one is used to express a harmonious union of love between human beings and also between God and human being. The article aims at exploring such conflation of love with geometry in the poetic works of John Donne, Henry Vaughn, Andrew Marvell and George Herbert, the four major Metaphysical Poets. doi: 10.3329/iiucs.v3i0.2663   IIUC STUDIES Vol. - 3, December 2006 (p 31-44)
Orwell's "Shooting an Elephant": Reflections on Imperialism and Neoimperialism
Authors: Alam Mohammed Sarwar
Published: June 2009

Imperialism has been the most powerful force in world history over last four or five centuries. The world has moved from the colonial to post-colonial era or neoimperialism. Throughout the period, the imperialists have changed their grounds and strategies in imperialistic rules. But the ultimate objective has remained the same- to rule and exploit the natives with their multifaceted dominance-technological, economic and military. Through dominance with these, they have been, to a great extent, successful in establishing their racial and cultural superiority. George Orwell is popularly known to be an anti-imperialist writer. This paper, I believe, will lead us to an almost different conclusion. Here, we discover the inevitable dilemma in a disguised imperialist. We discover the seeds of imperialism under the mask of anti-imperialism. In this regard, it studies his revealing short story "Shooting an Elephant". It also humbly approaches to refute Barry Hindess' arguments supporting neoimperialism.   doi: 10.3329/iiucs.v3i0.2664   IIUC STUDIES Vol. - 3, December 2006 (p 5-62)
Informal Islamic Education and its Role in Human Resource Development in Society: A Theoretical Evaluation
Authors: Alam Kamiz Uddin Ahmed , Muzahid Mohammad Aman Uddin
Published: June 2009

This article attempts to focus on Islamic education in the informal setting, its correspondence with human resource development and the role of this development to create a sound and balanced environment in society with moral and spiritual values. Firstly, the paper addresses education and its function in general and then education from Islamic perspective. Secondly, it discusses the character of informal Islamic education, the role players of the field of informal Islamic education, their status as teachers, the role of a teacher, the competencies of a teacher, and teacher - learner relationship in the light of Islamic culture and heritage. Finally, a proposal on the specific subject of Informal Islamic education and the strategies of imparting it are presented in the article.   doi: 10.3329/iiucs.v3i0.2667   IIUC STUDIES Vol. - 3, December 2006 (p 83-92)
Sayyid Mawdudi's Contribution towards Islamic Revivalism
Authors: Ushama Thameem , Osmani Noor Mohammad
Published: June 2009

doi: 10.3329/iiucs.v3i0.2668   IIUC STUDIES Vol. - 3, December 2006 (p 93-104)
Spotlight on Islam to the east of Bengal and particularly in the ages before judging the Islamic
Authors: Rafik AB
Published: June 2009

The full text of this article is in Arabic - see PDF below.doi: 10.3329/iiucs.v3i0.2669   IIUC STUDIES Vol. - 3, December 2006 (p 8-5)
Essence and impact of change in jurisprudence
Authors: Nizamuddin Abu Mohammed
Published: June 2009

The full text of this article is in Arabic - see PDF below.doi: 10.3329/iiucs.v3i0.2670   IIUC STUDIES Vol. - 3, December 2006 (p 9-14)
Methodology of Al Maududi in his Tafhimul Quran
Authors: Hafez D Ghiatholdin Mohamed
Published: June 2009

The full text of this article is in Arabic - see PDF below.doi: 10.3329/iiucs.v3i0.2671   IIUC STUDIES Vol. - 3, December 2006 (p 15-22)
Metaphorical indication of Nagib Mahfuz in his literature
Authors: Nadawi D Muhammad Najm
Published: June 2009

The full text of this article is in Arabic - see PDF below. doi: 10.3329/iiucs.v3i0.2673   IIUC STUDIES Vol. - 3, December 2006 (p 35-48)
'Qiara' of the Holy Quran and its impact upon Arabic literature
Authors: Safiuddin M
Published: June 2009

The full text of this article is in Arabic - see PDF below. doi: 10.3329/iiucs.v3i0.2674   IIUC STUDIES Vol. - 3, December 2006 (p 49-62)
Orientalism: the most serious challenge to Islam
Authors: Shauk S Islam
Published: June 2009

The full text of this article is in Arabic - see PDF below. doi: 10.3329/iiucs.v3i0.2675   IIUC STUDIES Vol. - 3, December 2006 (p 63-78).
'Istihad' and its role upon reforming of Islamic Jurisprudence
Authors: Nadawi Ur-Rehman
Published: June 2009

The full text of this article is in Arabic - see PDF below. doi: 10.3329/iiucs.v3i0.2676   IIUC STUDIES Vol. - 3, December 2006 (p 79-90)
Financial transactions with commercial papers in the light of Islamic Shariah
Authors: Rahman Mofizur
Published: June 2009

The full text of this article is in Arabic - see PDF below. doi: 10.3329/iiucs.v3i0.2677   IIUC STUDIES Vol. - 3, December 2006 (p 91-104)
Faith and morality education in child literature
Authors: Abdel-Samad D Mohamed
Published: June 2009

The full text of this article is in Arabic - see PDF below. doi: 10.3329/iiucs.v3i0.2679   IIUC STUDIES Vol. - 3, December 2006 (p 115-122)
Translation of the Holy Quran - Legitimacy and scholars opinion
Authors: Hossain Mohammed Bahaa Eddin
Published: June 2009

The full text of this article is in Arabic - see PDF below. doi: 10.3329/iiucs.v3i0.2681   IIUC STUDIES Vol. - 3, December 2006 (p 133-144
Position of Ancient Sects to Sunnah- An evaluational study
Authors: Abadi M Abul Lais Khair
Published: June 2009

The full text of this article is in Arabic - see PDF below. doi: 10.3329/iiucs.v3i0.2683   IIUC STUDIES Vol. - 3, December 2006 (p 155-164)
The Arabic word Hattah' as a prefix to Mudare Mansub' a grammatical study with reference from the Holy Quran
Authors: Islam ASM Tariqul
Published: June 2009

The full text of this article is in Arabic - see PDF below. doi: 10.3329/iiucs.v3i0.2684   IIUC STUDIES Vol. - 3, December 2006 (p 165-172)
A Microscale Modeling Tool for the Design and Optimization of Solid Oxide Fuel Cells
Authors: Liu Shixue , Kong Wei , Lin Zijing
Published: June 2009

A two dimensional numerical model of a solid oxide fuel cell (SOFC) with electrode functional layers is presented. The model incorporates the partial differential equations for mass transport, electric conduction and electrochemical reactions in the electrode functional layers, the anode support layer, the cathode current collection layer and at the electrode/electrolyte interfaces. A dusty gas model is used in modeling the gas transport in porous electrodes. The model is capable of providing results in good agreement with the experimental I-V relationship. Numerical examples are presented to illustrate the applications of this numerical model as a tool for the design and optimization of SOFCs. For a stack assembly of a pitch width of 2 mm and an interconnect-electrode contact resistance of 0.025 Ωcm2, a typical SOFC stack cell should consist of a rib width of 0.9 mm, a cathode current collection layer thickness of 200–300 μm, a cathode functional layer thickness of 20–40 μm, and an anode functional layer thickness of 10–20 μm in order to achieve optimal performance.