bluuebunny/crossref_metadata_2025 huggingface dataset:
MicroRNA Expression Is Required for Pancreatic Islet Cell Genesis in the Mouse
Authors: Lynn Francis C. , Skewes-Cox Peter , Kosaka Yasuhiro , McManus Michael T. , Harfe Brian D. , German Michael S.
Published: September 2007

OBJECTIVE—The generation of distinct cell types during the development of the pancreas depends on sequential changes in gene expression. We tested the hypothesis that microRNAs (miRNAs), which limit gene expression through posttranscriptional silencing, modulate the gene expression cascades involved in pancreas development.

RESEARCH DESIGN AND METHODS—miRNAs were cloned and sequenced from developing pancreata, and expression of a subset of these genes was tested using locked nucleic acid in situ analyses. To assess the overall contribution of miRNAs to pancreatic development, Dicer1, an enzyme required for miRNA processing, was conditionally deleted from the developing pancreas.

RESULTS—Sequencing of small RNAs identified over 125 miRNAs, including 18 novel sequences, with distinct expression domains within the developing pancreas. To test the developmental contribution of these miRNAs, we conditionally deleted the miRNA processing enzyme Dicer1 early in pancreas development. Dicer-null animals displayed gross defects in all pancreatic lineages, although the endocrine cells, and especially the insulin-producing β-cells, were most dramatically reduced. The endocrine defect was associated with an increase in the notch-signaling target Hes1 and a reduction in the formation of endocrine cell progenitors expressing the Hes1 target gene neurogenin3.

CONCLUSIONS—The expression of a unique profile of miRNAs is required during pancreas development and is necessary for β-cell formation.
l-Carnosine, a Substrate of Carnosinase-1, Influences Glucose Metabolism
Authors: Sauerhöfer Sibylle , Yuan Gang , Braun Gerald Stefan , Deinzer Martina , Neumaier Michael , Gretz Norbert , Floege Jürgen , Kriz Wilhelm , van der Woude Fokko , Moeller Marcus Johannes
Published: September 2007

OBJECTIVE—Carnosinase 1 (CN1) is a secreted dipeptidase that hydrolyzes l-carnosine. Recently, we have identified an allelic variant of human CN1 (hCN1) that results in increased enzyme activity and is associated with susceptibility for diabetic nephropathy in human diabetic patients. We therefore hypothesized that l-carnosine in the serum represents a critical protective factor in diabetic patients.

RESEARCH DESIGN AND METHODS— l-carnosine serum levels were manipulated in db/db mice, a model of type 2 diabetes. In a transgenic approach, hCN1 cDNA was expressed under the control of a liver-specific promoter in db/db mice, mimicking the expression pattern of hCN1 in humans.

RESULTS—Fasting plasma glucose as well as A1C levels rose significantly earlier and remained higher in transgenic animals throughout life. Body weights were reduced as a result of significant glucosuria. In an opposite approach, nontransgenic db/db mice were supplemented with l-carnosine. In these latter mice, diabetes manifested significantly later and milder. In agreement with the above data, serum fasting insulin levels were low in the transgenic mice and elevated by l-carnosine feeding. Insulin resistance and insulin secretion were not significantly affected by l-carnosine serum levels. Instead, a significant correlation of l-carnosine levels with β-cell mass was observed.

CONCLUSIONS—hCN1-dependent susceptibility to diabetic nephropathy may at least in part be mediated by altered glucose metabolism in type 2 diabetic patients.
LPIN2 Is Associated With Type 2 Diabetes, Glucose Metabolism, and Body Composition
Authors: Aulchenko Yurii S. , Pullen Jan , Kloosterman Wigard P. , Yazdanpanah Mojgan , Hofman Albert , Vaessen Norbert , Snijders Pieter J.L.M. , Zubakov Dmitry , Mackay Ian , Olavesen Mark , Sidhu Balbinder , Smith Vicki E. , Carey Alisoun , Berezikov Eugene , Uitterlinden André G. , Plasterk Ronald H.A. , Oostra Ben A. , van Duijn Cornelia M.
Published: September 2007

OBJECTIVE—To identify the type 2 diabetes gene located at chromosome 18p11.

RESEARCH DESIGN AND METHODS—We investigated the region in a young genetically isolated population by genotyping 34 single nucleotide polymorphisms (SNPs) in 78 case subjects and 101 control subjects. Two SNPs were selected and followed up in two cohorts. The first cohort came from a general Dutch population. In this cohort, association with type 2 diabetes was investigated using 616 type 2 diabetic case subjects and 2,890 control subjects; association with oral glucose tolerance test data was performed in 361 normoglycemic people. Association with fat distribution was studied in the second replication cohort, consisting of 836 people from the genetically isolated population.

RESULTS—At the initial step, we found that the common C allele of SNP rs3745012 was associated with type 2 diabetes (odds ratio 2.01, P = 0.03). This SNP is located at the 3′ untranslated region of the LPIN2 gene, which is a plausible candidate for type 2 diabetes and obesity. In the cohort from the general Dutch population, we demonstrated that rs3745012 interacts with BMI in determination of type 2 diabetes: whereas in subjects with high BMI, the common C allele is associated with type 2 diabetes, the same allele exhibits a neutral or protective effect in lean subjects (P = 0.05 overall effect, P = 0.02 interaction). Most remarkably, rs3745012 strongly affected composite insulin sensitivity index (P = 0.006 for overall effect, P = 0.004 for interaction). In the second replication cohort, we found that the allele C of rs3745012 increases trunk-to-legs fat mass ratio (P = 0.001) and may affect other fat-related measurements.

CONCLUSIONS—rs3745012 SNP of the LPIN2 gene is associated with type 2 diabetes and fat distribution.
Phosphorylation Barriers to Skeletal and Cardiac Muscle Glucose Uptakes in High-Fat–Fed Mice
Authors: Fueger Patrick T. , Lee-Young Robert S. , Shearer Jane , Bracy Deanna P. , Heikkinen Sami , Laakso Markku , Rottman Jeffrey N. , Wasserman David H.
Published: September 2007

OBJECTIVE—Muscle glucose uptake (MGU) is regulated by glucose delivery to, transport into, and phosphorylation within muscle. The aim of this study was to determine the role of limitations in glucose phosphorylation in the control of MGU during either physiological insulin stimulation (4 mU · kg−1· min−1) or exercise with chow or high-fat feeding.

RESEARCH DESIGN AND METHODS—C57BL/6J mice with (HK+/−) and without (WT) a 50% hexokinase (HK) II deletion were fed chow or high-fat diets and studied at 4 months of age during a 120-min insulin clamp or 30 min of treadmill exercise (n = 8–10 mice/group). 2-deoxy[3H]glucose was used to measure Rg, an index of MGU.

RESULTS—Body weight and fasting arterial glucose were increased by high-fat feeding and partial HK II knockout (HK+/−). Both high-fat feeding and partial HK II knockout independently created fasting hyperinsulinemia, a response that was increased synergistically with combined high-fat feeding and HK II knockout. Whole-body insulin action was suppressed by ∼25% with either high-fat feeding or partial HK II knockout alone but by >50% when the two were combined. Insulin-stimulated Rg was modestly impaired by high-fat feeding and partial HK II knockout independently (∼15–20%) but markedly reduced by the two together (∼40–50%). Exercise-stimulated Rg was reduced by ∼50% with high-fat feeding and partial HK II knockout alone and was not attenuated further by combining the two.

CONCLUSIONS—In summary, impairments in whole-body metabolism and MGU due to high-fat feeding and partial HK II knockout combined during insulin stimulation are additive. In contrast, combining high-fat feeding and partial HK II knockout during exercise causes no greater impairment in MGU than the two manipulations independently. This suggests that MGU is impaired during exercise by high-fat feeding due to, in large part, a limitation in glucose phosphorylation. Together, these studies show that the high-fat–fed mouse is characterized by defects at multiple steps of the MGU system that are precipitated by different physiological conditions.
Common Variants of the Novel Type 2 Diabetes GenesCDKAL1andHHEX/IDEAre Associated With Decreased Pancreatic β-Cell Function
Authors: Pascoe Laura , Tura Andrea , Patel Sheila K. , Ibrahim Ibrahim M. , Ferrannini Ele , Zeggini Eleftheria , Weedon Michael N. , Mari Andrea , Hattersley Andrew T. , McCarthy Mark I. , Frayling Timothy M. , Walker Mark ,   for the RISC Consortium and the U.K. Type 2 Diabetes Genetics Consortium
Published: September 2007

OBJECTIVE— Type 2 diabetes is characterized by impaired pancreatic β-cell function and decreased insulin sensitivity. Genome-wide association studies have identified common, novel type 2 diabetes susceptibility loci within the FTO, CDKAL1, CDKN2A/CDKN2B, IGF2BP2, HHEX/IDE, and SLC30A8 gene regions. Our objective was to explore the relationships between the diabetes-associated alleles and measures of β-cell function and whole-body insulin sensitivity.

RESEARCH DESIGN AND METHODS— A total of 1,276 healthy subjects of European ancestry were studied at 19 centers. Indexes of β-cell function (including 30-min insulin response and glucose sensitivity) were derived from a 75-g oral glucose tolerance test, and whole-body insulin sensitivity (M/I) was assessed by hyperinsulinemic-euglycemic clamp. Genotype/phenotype relationships were studied by linear trend analysis correcting for age, sex, and recruitment center.

RESULTS— CDKAL1 and HHEX/IDE diabetes-associated alleles were both associated with decreased 30-min insulin response (both P = 0.0002) and decreased pancreatic β-cell glucose sensitivity (P = 9.86 × 10−5 and 0.009, respectively), and these relationships remained after correction for M/I. The FTO susceptibility allele showed a weak but consistent association with increased adiposity, which in turn was linked to a decrease in M/I. However, none of the other novel diabetes susceptibility alleles were associated with insulin sensitivity.

CONCLUSIONS— CDKAL1 and HHEX/IDE diabetes-associated alleles are associated with decreased pancreatic β-cell function, including decreased β-cell glucose sensitivity that relates insulin secretion to plasma glucose concentration. We confirmed the association between the FTO allele and increased adiposity, but none of the other novel susceptibility alleles were associated with whole-body insulin sensitivity.
Attenuation of Amydgala and Frontal Cortical Responses to Low Blood Glucose Concentration in Asymptomatic Hypoglycemia in Type 1 Diabetes
Authors: Dunn Joel T. , Cranston Iain , Marsden Paul K. , Amiel Stephanie A. , Reed Laurence J.
Published: September 2007

OBJECTIVE—Loss of ability to recognize hypoglycemia (hypoglycemia unawareness) increases risk of severe hypoglycemia threefold in insulin-treated diabetes. We set out to investigate the cerebral correlates of unawareness in type 1 patients.

RESEARCH DESIGN AND METHODS—Regional changes in brain glucose kinetics were measured using [18F]-fluorodeoxyglucose (FDG) positron emission tomography (PET), in 13 men with type 1 diabetes—6 with hypoglycemia awareness and 7 with hypoglycemia unawareness—at euglycemia (5 mmol/l) and hypoglycemia (2.6 mmol/l), in random order.

RESULTS—Epinephrine responses to hypoglycemia were reduced in hypoglycemia unawareness (P < 0.0003), as were symptoms. Statistical parametric mapping (SPM) of FDG uptake using SPM2 at a statistical threshold of P < 0.005 showed increased FDG uptake in left amygdala in hypoglycemia awareness, but not in hypoglycemia unawareness (region of interest analysis −0.40 ± 1.03 vs. 3.66 ± 0.42, respectively; P = 0.007), and robust increase in bilateral ventral striatum during hypoglycemia (region of interest analysis hypoglycemia unawareness 3.52 ± 1.02 vs. awareness 6.1 ± 0.53; P = 0.054). Further analysis at the statistical threshold of P < 0.01 showed bilateral attenuated activation of brain stem regions and less deactivation in lateral orbitofrontal cortex in hypoglycemia unawareness.

CONCLUSIONS—Ventral striatal, amygdala, brain stem, and orbitofrontal responses to hypoglycemia indicate engagement of appetitive motivational networks, associated with integrated behavioral responses to hypoglycemia. Reduced responses in these networks in hypoglycemia unawareness, particularly failure of amygdala and orbifrontal cortex responses, suggest habituation of higher behavioral responses to hypoglycemia as a basis for unawareness. New approaches may be needed to restore awareness effectively in practice.
Selected Italian Projects
Authors: Peckham Andrew , Tozzi Lucia
Published: September 2007

Rationalism remains at the sidelines of contemporary architecture in Italy – a latent current rather than a leading force. Andrew Peckham and Lucia Tozzi reveal how this stubborn but rich seam is manifesting itself: in Cino Zucchi's substantial housing scheme on the outskirts of Milan; Werner Tscholl's insertion into Schloss Sigmundskron/Castel Firmiano; Beniamino Servino's continued work on the Nursery School in Formicola, Caserta; and C+S Associati's Nursery School at Covolo di Pederobba in Treviso. Copyright © 2007 John Wiley & Sons, Ltd.
An Interview with Giorgio Grassi
Authors: Tozzi Lucia
Published: September 2007

In January 2007, Lucia Tozzi visited Giorgio Grassi's office in Milan. Their conversation touched on Grassi's recent work on Leon Battista Alberti, which is examined here in the context of Grassi's obliquely expressed views on contemporary architecture and the cult of personality. As perhaps the most intellectually rigorous and formally consistent Rationalist architect of his generation, Grassi's work and thinking retain a hermetic aspect, but one notable for its philosophical self‐questioning and underlying political commitment. Copyright © 2007 John Wiley & Sons, Ltd.
Concrete Constructs: The Limits of Rationalism in Swiss Architecture
Authors: Moravánszky Ákos
Published: September 2007

Ákos Moravánszky explains why for him ‘the traces of Mediterranean Rationalism in the new Swiss‐German architecture are like the imitation stitching on the moulded plastic dashboard of a new car’. It is an influence which, despite the undeniable impact of Aldo Rossi and the Ticino School at ETH Zurich in the 1970s, remains skin‐deep, sharing little with the present in terms of ideology or the interpretation of the historic past. Copyright © 2007 John Wiley & Sons, Ltd.
Selected Swiss Projects
Authors: Schmiedeknecht Torsten
Published: September 2007

Torsten Schmiedeknecht describes four Swiss buildings that adopt a formal language of Rationalist rigour to dramatic effect. Despite all being institutional buildings, they vary widely in their treatments interpreting a Rationalist vocabulary in very different ways, from the unstinting austerity of GWJ Architekten's UVEK Administration Centre to Andrea Bassi's intentionally playful La Maladière Primary School in Neuchâtel. Copyright © 2007 John Wiley & Sons, Ltd.
Schinkel's Order: Rationalist Tendencies in German Architecture
Authors: Durth Werner , May Roland
Published: September 2007

Germany can be viewed as the natural home of the Rationalist impulse. Two of Germany's most influential architects, Karl Friedrich Schinkel and Mies van der Rohe, have been admired the world over for their sense of tectonic order and purist form. Werner Durth and Roland May trace a modern history of the tendency, which began with the early 20th‐century rediscovery of Schinkel and has been continued to the present in the work of OM Ungers. Copyright © 2007 John Wiley & Sons, Ltd.
Selected German Projects
Authors: Durth Werner , May Roland
Published: September 2007

In the last two decades, Rationalism has been revisited in Germany. As Werner Durth and Roland May demonstrate in these four projects it can provide very different strategies for dealing with often complex urban contexts, whether it provides: ‘order for disparate surroundings’ as in the Ohel Jakob Synagogue in Munich; a consistent vocabulary for the regeneration of a Modernist GDR housing scheme as at Thuringia; a representative elegance and inbuilt flexibility as at Frankfurt Airport's Terminal 3; or a means of reasserting the orientation and materiality of earlier buildings on an existing site as in Hans Kollhoff's Het Palais Condominium in Breda in the Netherlands. Copyright © 2007 John Wiley & Sons, Ltd.
Dialogues with OMU
Authors: Peckham Andrew , Schmiedeknecht Torsten
Published: September 2007

In January 2007, guest‐editors Andrew Peckham and Torsten Schmiedeknecht met with OM Ungers in the library of his Belvederestrasse house in Cologne Müngersdorf.1 A ‘round table’ discussion followed, with the architect, his wife, daughter and archivist, prompting a series of dialogues with Ungers centred on his built works, projects, thinking and teaching. The authors gained a unique insight into Ungers' varied and often influential career, and took the opportunity to re‐examine the preconceptions surrounding it. Copyright © 2007 John Wiley & Sons, Ltd.
French Rationalism: A Broken Tradition
Authors: Abram Joseph
Published: September 2007

From the golden era of 1960s Rationalism to the present Inquietude Lucide, Joseph Abram describes the Rationalist tendencies in French architecture. Once dominated by the spectres of Le Corbusier and Auguste Perret, the rational was deeply embedded in French tectonic culture. Despite the current reassertion of the rational, the future, as Abram explains, appears less certain. Copyright © 2007 John Wiley & Sons, Ltd.
An Open and Flexible Tradition
Authors: Montaner Josep Maria
Published: September 2007

There is a rich tradition of Rationalist architecture in Spain, dating back to the years immediately after the Spanish Civil War and then the period of postwar recovery in the 1950s. Josep Maria Montaner explains how this has developed across time into a contemporary interpretation of Rationalism that is versatile and inclusive, often combining Functionalist ideas with a stripped‐back repertoire of materials and elements. Copyright © 2007 John Wiley & Sons, Ltd.
Selected Spanish Projects
Authors: Montaner Josep Maria
Published: September 2007

Josep Maria Montaner describes four buildings that epitomise the flexibility of the Rationalist tendency in Spain. These span the Mies‐inspired minimalism of Javier Garcia Solera; housing schemes that are designed around the present needs of their occupants for adaptable and well‐ventilated spaces, despite being influenced by earlier Rationalist vocabularies; and Carlos Ferrater's JC Decaux Headquarters in Madrid that uses ‘the order and tradition’ of Modernist architecture to create continuity with existing buildings on its site. Copyright © 2007 John Wiley & Sons, Ltd.
Gert Wingårdh
Authors: Hebb Timothy Tore
Published: September 2007

From his main office in Gothenburg, Sweden's second city, Gert Wingårdh has spawned a practice that has brought him national success. He has completed two embassy buildings for the Swedish foreign office in Washington DC and Berlin and two major museums. Timothy Tore Hebb describes the work of an architect whose designs are able to be both responsive to the natural environment and ingenious in their juxtapositions and contrasts. Copyright © 2007 John Wiley & Sons, Ltd.
Mythic Collaboration
Authors: Spiller Neil
Published: September 2007

Controversially, Neil Spiller risks the fallout and confronts the trend for multidisciplinary architectural collaborations head‐on. He explains why he believes corporate team management can only lead to the mundane and the mediocre, denying individuality, creativity and vision. Copyright © 2007 John Wiley & Sons, Ltd.
Home Body
Authors: van Schaik Leon
Published: September 2007

Leon van Schaik reviews Households, a compelling photographic documentary project by artist and architect Mark Robbins, which portrays actual people in their own homes. Eschewing the ‘somnolent’ mode of styled interior photography, which is more about what people wish for rather than where they actually live, Robbins captures the intimacy of everyday domestic settings and relationships and in so doing engages ‘architecture with the full panoply of human emotions’. Copyright © 2007 John Wiley & Sons, Ltd.
Structural Changes in the BODIPY Dye PM567 Enhancing the Laser Action in Liquid and Solid Media
Authors: García‐Moreno I. , Amat‐Guerri F. , Liras M. , Costela A. , Infantes L. , Sastre R. , López Arbeloa F. , Bañuelos Prieto J. , López Arbeloa Í.
Published: September 2007

In the search for more efficient and photostable solid‐state dye lasers, newly synthesized analogs of the borondipyrromethene (BODIPY) dye PM567, bearing the polymerizable methacryloyloxypropyl group at position 2 (PMoMA) or at positions 2 and 6 (PDiMA), have been studied in the form of solid copolymers with methyl methacrylate (MMA). The parent dye PM567, as well as the model analogs bearing the acetoxypropyl group in the same positions, PMoAc and PDiAc, respectively, have been also studied both in liquid solvents and in solid poly(MMA) (PMMA) solution. Although in liquid solution PMoAc and PDiAc have the same photophysical properties as PM567, PDiAc exhibited a photostability up to 10 times higher than that of PM567 in ethanol under 310 nm‐irradiation. The possible stabilization factors of PDiAc have been analyzed and discussed on the basis of the redox potentials, the ability for singlet molecular oxygen [O2(1Δg)] generation, the reactivity with O2(1Δg), and quantum mechanical calculations. Both PMoAc and PDiAc, pumped transversally at 532 nm, lased in liquid solution with a high (up to 58 %), near solvent‐independent efficiency. This enhanced photostabilization has been also observed in solid polymeric and copolymeric media. While the solid solution of the model dye PDiAc in PMMA showed a lasing efficiency of 33 %, with a decrease in the laser output of ca. 50 % after 60 000 pump pulses (10 Hz repetition rate) in the same position of the sample, the solid copolymer with the double bonded chromophore, COP(PDiMA‐MMA), showed lasing efficiencies of up to 37 %, and no sign of degradation in the laser output after 100 000 similar pump pulses. Even under the more demanding repetition rate of 30 Hz, the laser emission from this material remained at 67 % of its initial laser output after 400 000 pump pulses, which is the highest laser photostability achieved to date for solid‐state lasers based on organic polymeric materials doped with laser dyes. This result indicates that the double covalent linkage of the BODIPY chromophore to a PMMA polymeric matrix is even more efficient than the simple linkage, for its photostabilization under laser operation.
Correlations between Percolation Threshold, Dispersion State, and Aspect Ratio of Carbon Nanotubes
Authors: Li J. , Ma P. C. , Chow W. S. , To C. K. , Tang B. Z. , Kim J.‐K.
Published: September 2007

Critical factors that determine the percolation threshold of carbon nanotube (CNT)‐reinforced polymer nanocomposites are studied. An improved analytical model is developed based on an interparticle distance concept. Two dispersion parameters are introduced in the model to correctly reflect the different dispersion states of CNTs in the matrix—entangled bundles and well‐dispersed individual CNTs. CNT–epoxy nanocomposites with different dispersion states are fabricated from the same constituent materials by employing different processing conditions. The corresponding percolation thresholds of the nanocomposites vary over a wide range, from 0.1 to greater than 1.0 wt %, and these variations are explained in terms of dispersion parameters and aspect ratios of CNTs. Important factors that control the percolation threshold of nanocomposites are identified based on the comparison between modeling data and experimental results.
Novel Nano‐Structured Silica‐Based Electrolytes Containing Quaternary Ammonium Iodide Moieties
Authors: Cerneaux S. , Zakeeruddin S. M. , Pringle J. M. , Cheng Y.‐B. , Grätzel M. , Spiccia L.
Published: September 2007

A series of new hybrid organic‐inorganic molecules were prepared either by grafting of aminopropyltriethoxysilane (APTS) on silica nanoparticles followed by quaternarization of the nitrogen with ethyl, heptyl and isopropyl iodides or by grafting of N,N,N‐triethyl‐3‐(triethoxysilyl)propan‐1‐aminium iodide and N,N,N‐tridodecyl‐3‐(triethoxysilyl)propan‐1‐aminium iodide onto the silica nanoparticles. These new materials were used as iodide sources in the preparation of electrolyte solutions for dye‐sensitized solar cells (DSSCs). The performance of DSSCs was studied as a function of the nature of the solvent, the nature of the dye, the concentration of the modified silica in the electrolyte system and the silica content introduced during the hybrid synthesis. An efficiency of 8.5 % was obtained for solar cells containing the triethyl ammonium iodide salt at a concentration of 1 M in either acetonitrile (AN) or 3‐methoxypropionitrile (MPN) under an illumination of 10 mW cm–2, the equivalent of 0.1 Sun at AM 1.5G. At 1 Sun (100 mW cm–2, efficiencies of 6.6 % and 5.1 % were recorded for the AN and MPN‐based electrolytes, respectively.
Atomic force microscopy observations of the topography of regenerated silk fibroin aggregations
Authors: Huang Tao , Ren Peng , Huo Bo
Published: September 2007

How fibroin molecules fold themselves and further self‐assemble into aggregations with specific structures when the solution concentration increases is the key to understanding the natural silk‐forming process of the silkworm. A regenerated Bombyx mori silk fibroin solution was prepared, and serially diluted solutions were coated on aminated coverslips. Atomic force microscopy (AFM) observations of the topography of fibroin molecules revealed a transformation from rodlike aggregations 100–200 nm long to small globules 50 nm in diameter with decreasing concentrations. When the incubation duration increased, the aggregations of fibroin molecules showed a self‐assembling process, which was measured with AFM. In particular, after the molecules were incubated for more than 20 min, rodlike micelles formed and were distributed evenly on the surface of the aminated slides. Flow chamber technology was used to study the effect of the shear loading on the topography of the fibroin molecular aggregations. After a shear loading was applied, larger rodlike particles formed at a higher incubation concentration in comparison with those at a lower concentration and were obviously oriented along the direction of fluid flow. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Spectroscopic and electrochemical studies on block‐polymer/PMMA blend based composite polymer electrolytes
Authors: Zhang Shupeng , Fu Xiangkai , Gong Yongfeng
Published: September 2007

Poly(methylmethacrylate)(PMMA)/oxymethylene‐linked polyoxyethylene multi‐block polymer(Om‐POEn, where n represents number of unit CH2CH2O) blend based composite electrolyte films containing different lithium salt concentration and nanofillers' content are prepared using solvent evaporation technique. The interaction of polymer–salt complex has been confirmed using FTIR spectral studies. The figuration of CPE was studied by XRD. Ionic conductivity and thermal behavior of the CPEs were studied with various salt concentrations, temperature, and nanofillers' content. The surface structure of the CPE is also investigated using scanning electron microscopy. The high room temperature ionic conductivity, transmittivity in the visible region, and thermal stability make these CPEs potential candidates as solid‐like electrolytes for electrochemical devices. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Nanocomposite polymer electrolytes containing silica nanoparticles: Comparison between poly(ethylene glycol) and poly(ethylene oxide) dimethyl ether
Authors: Park Jung Tae , Lee Kyung Ju , Kang Moon‐Sung , Kang Yong Soo , Kim Jong Hak
Published: September 2007

Nanocomposite polymer electrolytes consisting of low molecular weight poly(ethylene oxide) (PEO), iodine salt MI (M = K+, imidazolium+), and fumed silica nanoparticles have been prepared and characterized. The effect of terminal group in PEO, i.e., hydroxyl (OH) and methyl (CH3) using poly(ethylene glycol) (PEG) and PEO dimethyl ether (PEODME), respectively, was investigated on the interactions, structures, and ionic conductivities of polymer electrolytes. Wide angle X‐ray scattering (WAXS), differential scanning calorimetry (DSC), and complex viscositymeasurements clearly showed that the gelation of PEG electrolytes occurred more effectively than that of PEODME electrolytes. It was attributed to the fact that the hydroxyl groups of PEG participated in the hydrogen‐bonding interaction between silica nanoparticles, and consequently helped to accelerate the gelation reaction, as confirmed by FTIR spectroscopy. Because of its interaction, the ionic conductivities of PEG electrolytes (maximum value ∼ 6.9 × 10−4 S/cm) were lower than that of PEODME electrolytes (2.3 × 10−3 S/cm). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Nonoxynol‐9‐α‐cyclodextrin inclusion compound and its application for the controlled release of nonoxynol‐9 spermicide
Authors: Suk Whang Hyun , Hunt Marcus A. , Wrench Nicola , Hockney Jessica E. , Farin Charlotte E. , Tonelli Alan E.
Published: September 2007

Nonoxynol‐9 (N‐9) is the most active ingredient in commercially available spermicidal products in the United States. There are many applications of cyclodextrin inclusion complexes (CD‐ICs), but there are no reported studies investigating the formation of and controlled release from a N‐9 spermicide‐CD‐IC. We have successfully formed the inclusion compound between N‐9 and α‐CD using a solution‐heating technique. The N‐9‐α‐CD‐IC was characterized by Fourier Transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and wide angle X‐ray diffraction observations. Silicone elastomer (SILASTIC MDX4‐4210) film embedded with crystalline N‐9‐α‐CD‐IC was prepared and evaluated for its efficacy in the controlled release of N‐9 spermicide against bovine sperm. Silicone elastomer with N‐9‐α‐CD‐IC was as successful in reducing the motility and viability of bovine spermtazoa as silicone elastomer swollen with an equivalent amount of neat N‐9. The permeability of the flexible silicone elastomer apparently enables the N‐9 spermicide to diffuse from its embedded inclusion complex crystals to contact, immobilize, and kill bovine sperm cells. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Modification of polyethylene surface using plasma polymerization of silane
Authors: Deshmukh R. R. , Shetty A. R.
Published: September 2007

In the present study plasma polymerization of tetraethylorthosilicate and hexamethyldisiloxane was carried out on polyethylene film with an aim of enhancing barrier properties. The glow discharge was obtained at 0.2 mbar using 13.56 MHz radio frequency source capable of giving power out put up to 100 W. The monomer vapors were passed in the system at the rate of 15 SCCM. The extent of deposition was determined from the weight gain study and the morphology was studied using SEM. Films were further characterized by surface energy measurement, ATR‐FTIR and ESCA analysis. Since PE is widely used for packaging and in this process a thin layer of glass‐like transparent SiOx was deposited, therefore it was thought necessary to study permeability to water vapors. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Novel Deoxyxylulosephosphate‐Reductoisomerase Inhibitors: Fosmidomycin Derivatives with Spacious Acyl Residues
Authors: Ortmann Regina , Wiesner Jochen , Silber Katrin , Klebe Gerhard , Jomaa Hassan , Schlitzer Martin
Published: September 2007

1‐Deoxy‐D‐xylulose‐5‐phosphate reductoisomerase (Dxr) represents an essential enzyme of the mevalonate‐independent pathway of the isoprenoid biosynthesis. Using fosmidomycin as a specific inhibitor of Dxr, this enzyme was previously validated as target for the treatment of malaria and bacterial infections. The replacement of the formyl residue of fosmidomycin by spacious acyl residues yielded inhibitors active in the micromolar range. As predicted by flexible docking, evidence was obtained for the formation of a hydrogen bond between an appropriately placed carbonyl group in the acyl residue and the main‐chain NH of Met214 located in the flexible catalytic loop of the enzyme.
Biodegradation of fuel oil hydrocarbons by a mixed bacterial consortium in sandy and loamy soils
Authors: Hawle‐Ambrosch Elisabeth , Riepe Wolfgang , Dornmayr‐Pfaffenhuemer Marion , Radax Christian , Holzinger Anita , Stan‐Lotter Helga
Published: September 2007

The aerobic degradation of light fuel oil in sandy and loamy soils by an environmental bacterial consortium was investigated. Soils were spiked with 1 or 0.1% of oil per dry weight of soil. Acetone extracts of dried soils were analyzed by GC and the overall degradation was calculated by comparison with hydrocarbon recovery from uninoculated soils. In sandy soils, the sum of alkanes n‐C12 to n‐C23 was degraded to about 45% within 6 days at 20°C and to 27–31% within 28 days, provided that moisture and nutrients were replenished. Degradation in loamy soil was about 12% lower. The distribution of recovered alkanes suggested a preferential degradation of shorter chain molecules (n‐C12 to n‐C16) by the bacterial consortium. Partial 16S rDNA sequences indicated the presence of strains of Pseudomonas aeruginosa, Pseudomonas citronellolis, and Stenotrophomonas maltophilia. Toxicity tests using commercial standard procedures showed a moderate inhibition of bacterial activity. The study showed the applicability of a natural microbial community for the degradation of oil spills into soils at ambient temperatures.
Function of the SIRT1 protein deacetylase in cancer
Authors: Stünkel Walter , Peh Bee Keow , Tan Yong Cheng , Nayagam Vasantha M. , Wang Xukun , Salto‐Tellez Manuel , Ni BinHui , Entzeroth Michael , Wood Jeanette
Published: September 2007

The NAD+‐dependent protein deacetylase SIRT1 is linked to cellular survival pathways by virtue of keeping the tumor suppressor gene p53 and members of the forkhead transcription factor family deacetylated. To validate SIRT1 as a therapeutic anti‐cancer target, we performed immunohistochemistry experiments to study the in vivo expression of SIRT1 in cancer specimens. We show that human SIRT1 is highly expressed in cancer cell lines as well as in tissue samples from colon carcinoma patients. Interestingly, there is a strong cytosolic component in the SIRT1 expression pattern. We further characterized SIRT1 in p53‐wild‐type and ‐mutant cell lines and show that SIRT1 mRNA‐knockdown leads to a p53‐independent decrease of cell proliferation and induction of apoptosis. In addition, SIRT1 expression has been found to be inducible upon DNA damage. A previously discovered small molecule SIRT1 inhibitor with nanomolar in vitro activity has been tested in cancer relevant assays. The SIRT1 inhibitory compound showed no potent anti‐proliferative activity despite hitting its molecular target within tumor cells. From these studies we conclude that it may not be sufficient to block the catalytic function of SIRT1, and that its survival effects may be mainly brought about by means other then the deacetylase function. The increased cytosolic expression of SIRT1 in cancer cells could be an indicator of such novel functions.
Biosynthesis of 5‐deoxyflavanones in microorganisms
Authors: Yan Yajun , Huang Lixuan , Koffas Mattheos A. G.
Published: September 2007

Flavanones are the common precursors of plant polyphenolic compounds collectively known as flavonoids. Leguminous plants have evolved a distinct class of flavanone molecules, known as 5‐deoxyflavanones that play important roles in their symbiotic interactions. A four‐step metabolic circuit was constructed inEscherichia coliwith plant genes from heterologous origins: 4‐coumarate:coenzyme A ligase fromPetroselinum crispum, chalcone synthases (CHS) fromMedicago sativaandPetunia x hybridaand chalcone reductase and chalcone isomerase fromM. sativa.Evaluation of the different recombinant strains in shake flask experiments demonstrated thatP. hybridarather thanM. sativaCHS resulted in the highest liquiritigenin production levels in glucose minimal medium, starting from precursorp‐coumaric acid. Expression of the same recombinant pathway inSaccharomyces cerevisiaeresulted in the accumulation of both 5‐hydroxyflavanone and 5‐deoxyflavanone, with the yields of the later lower than that achieved inE. coli.Other phenylpropanoid acid precursors, such as cinnamic acid and caffeic acid could also be metabolized through the recombinant pathway, yielding corresponding 5‐deoxyflavanone compounds. The construction of such recombinant strains for 5‐deoxyflavanone biosynthesis offers an alternative way to biochemically characterize flavonoid biosynthetic enzymes and promising production platforms for the biosynthesis of such high‐value natural products.
Protonation free energy levels in complex molecular systems
Authors: Antosiewicz Jan M.
Published: September 2007

All proteins, nucleic acids, and other biomolecules contain residues capable of exchanging protons with their environment. These proton transfer phenomena lead to pH sensitivity of many molecular processes underlying biological phenomena. In the course of biological evolution, Nature has invented some mechanisms to use pH gradients to regulate biomolecular processes inside cells or in interstitial fluids. Therefore, an ability to model protonation equilibria in molecular systems accurately would be of enormous value for our understanding of biological processes and for possible rational influence on them, like in developing pH dependent drugs to treat particular diseases. This work presents a derivation, by thermodynamic and statistical mechanical methods, of an expression for the free energy of a complex molecular system at arbitrary ionization state of its titratable residues. This constitutes one of the elements of modeling protonation equilibria. Starting from a consideration of a simple acid–base equilibrium of a model compound with a single tritratable group, we arrive at an expression which is of general validity for complex systems. The only approximation used in this derivation is the postulating that the interaction energy between any pair of titratable sites does not depend on the protonation states of all the remaining ionizable groups. © 2007 Wiley Periodicals, Inc. Biopolymers 89: 262–269, 2008.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Cα‐Methyl proline: A unique example of split personality
Authors: Moretto Alessandro , Terrenzani Francesco , Crisma Marco , Formaggio Fernando , Kaptein Bernard , Broxterman Quirinus B. , Toniolo Claudio
Published: September 2007

Methylation at the Cα‐position of a Pro residue was expected to lock the preceding tertiary amide (ω) torsion angle of the resulting (αMe)Pro to the trans disposition and to restrict the ϕ,ψ surface to the single region where the 310/α‐helices are found (in this five‐membered ring residue ϕ is severely constrained to about ±65° by its cyclic nature). The results of the present X‐ray diffraction work on a selected set of four Nα‐blocked, (αMe)Pro‐containing, dipeptide N′‐alkylamides clearly show that, although the region of the conformational map largely preferred by (αMe)Pro would indeed be that typical of 310/α‐helices, the semi‐extended [type‐II poly(Pro)n helix] region can also be explored by this extremely sterically demanding Cα‐tetrasubstituted α‐amino acid. In addition, the known high propensity for β‐turn formation of the Pro residue is further enhanced in peptides based on its Cα‐methylated derivative. © 2007 Wiley Periodicals, Inc. Biopolymers 89: 465–470, 2008.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Stabilization of the N‐terminal β‐hairpin of ubiquitin by a terminal hydrophobic cluster
Authors: Riemen Alex J. , Waters Marcey L.
Published: September 2007

Study of model β‐hairpin peptides allows for better understanding of the factors involved in the formation of β‐sheet secondary structure in proteins. It is known that turn sequence, sidechain–sidechain interactions, interstrand hydrogen bonding, and β‐sheet propensity of residues are all important for β‐hairpin stability in aqueous solution. However, interactions of the sidechains of the terminal residues of hairpins are thought to contribute little to overall hairpin stability since these residues are typically frayed. Here, the authors report a stabilizing hydrophobic cluster of residues at the termini of the naturally occurring excised N‐terminal β‐hairpin of Ubiquitin that folds autonomously in aqueous solution. Our data show that deletion of Met1 and Val17 from this hairpin destabilized the folded state in both aqueous solution and in aqueous‐methanol solutions. These results suggest that interactions of terminal residues which are usually frayed can nonetheless contribute significantly to overall stability of β‐hairpin. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90: 394–398, 2008.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Participation in research program
Authors: Zhou Xuanwei , Lin Juan , Yin Yizhou , Sun Xiaofen , Tang Kexuan
Published: September 2007

A novel course, “Participation in Research Program (PRP)” in life sciences is open for 1st to 3rd year undergraduates. PRP introduces the principles of a variety of biological methods and techniques and also offers an opportunity to explore some specific knowledge in more detail prior to thesis research. In addition, the PRP introduces some methodologies that have been proven to be successful at each institution to participants. Through disciplines crossing, students were trained theoretically and practically about modern techniques, facilitating the efficient commutation of general laboratory skills and modern laboratory skills, and the possession of higher research ability. Therefore, during some basic training (e.g., usage and maintenance of equipments, designing and completing experiments, analyzing data and reporting results, etc.), a series of capabilities are strengthened, such as basic experimental skills, searching appropriate methods, explaining unknown biological phenomena, and the capacity of solving problems. To determine the efficiency of these strategies, we carefully examined students' performance and demonstrated the progress in students' basic abilities of scientific research in their training.
Isolation of RNA and RT‐PCR, cloning, and sequencing of noncoding RNAs from fungi*
Authors: Luo Yuping , Gong Xi , Xu Ling , Li Siguang
Published: September 2007

RNomics, the understanding of functional RNAs and their interactions at a genomic level, is of utmost practical and theoretical importance in modern life sciences. To introduce our students to the techniques and promise of this emerging field, a practical class activity for advanced undergraduate students in biochemistry and molecular biology is described. In these exercises, students first identify noncoding RNA from different fungi by computational methods and analyze their transcription regulation signals and splice signals by bioinformatics tools, then isolate total RNA from these fungi, and finally verify these noncoding RNA gene expressions by reverse transcriptase‐polymerase chain reaction, cloning, and sequencing. This activity not only introduces students to the concept of RNomics, noncoding RNA, and RNA splicing, but also introduces students to the practice of basic molecular techniques. The natural combination of the genome projects and bioinformatics with modern molecular biology techniques is considered a major advantage of this laboratory course.
Engaging the learner: Embedding information literacy skills into a biotechnology degree
Authors: Ward Helena , Hockey Julie
Published: September 2007

One of the challenges of the Biotechnology industry is keeping up to date with the rapid pace of change and that much of the information, which students learn in their undergraduate studies, will be out of date in a few years. It is therefore crucial that Biotechnology students have the skills to access the relevant information for their studies and critically evaluate the vast volume of information and its sources. By developing information literacy skills, which are part of lifelong learning, Biotechnology graduates are better prepared for their careers. Students also need to understand the issues related to the use of information such as social, political, ethical, and legal implications. This paper will outline the embedding of information literacy skills within the Biotechnology degree at the University of South Australia. Examples of specific activities and their link to assessment will be discussed.
Improving Thai students' understanding of concepts in protein purification by using Thai and English versions of a simulation program*
Authors: Phornphisutthimas Somkiat , Panijpan Bhinyo , Wood Edward J. , Booth Andrew G.
Published: September 2007

To support student learning in biochemistry and related courses, a simulation program, the Protein Purification Program, offers an alternative multimedia‐based tool. This program has now been translated to produce a Thai version. However, translation from the original into the Thai language is limited by the differences between the language characteristics of English and Thai. Therefore, use of the program with Thai students had a twofold purpose. It helped their understanding of the concepts of protein purification by allowing code switching between the languages, but it also improved their understanding of, and competence in scientific English, which is a vital skill for functioning as a modern biochemist. According to the results of the questionnaires, undergraduates using the Thai/English program scored significantly higher than those using only the English language program (p < 0.05). In addition, the interview data suggested that the Thai/English program had improved student understanding of the concepts of protein purification to a greater extent than a single language (English) program. Students' overall preference in terms of their learning using the Thai/English program was 4.15 on a 1–5 Likert scale.
Why the linkage of glycogen to glycogenin was so difficult to determine
Authors: Whelan William J.
Published: September 2007

Glycogenin is the self‐glucosylating enzyme that primes mammalian and yeast glycogen synthesis. It proved to be the long‐suspected, covalently bound protein component of glycogen. One of the most difficult aspects in elucidating the role of glycogenin was to learn the nature of its covalent bond to glycogen.
Hydrogenation of the Ce(Rh1‐xIrx)Ga System: Occurrence of Antiferromagnetic Ordering in the Hydrides Ce(Rh1‐xIrx)GaH1.8.
Authors: Chevalier B. , Heying B. , Rodewald U. Ch. , Sebastian C. Peter , Bauer E. , Poettgen R.
Published: September 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
The Crystal Structure of γ‐AlD3.
Authors: Brinks H. W. , Brown C. , Jensen C. M. , Graetz J. , Reilly J. J. , Hauback B. C.
Published: September 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Low Temperature Crystal Structure of [Cr(NH3)6](BF4)3.
Authors: Gorska N. , Hetmanczyk L. , Lasocha W. , Mikuli E.
Published: September 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.