bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of wafer temperature determination for the study of unintentional parameter influences for the MOVPE of III‐nitrides
Authors: Hardtdegen H. , Kaluza N. , Steins R. , Cho Y. S. , Sofer Z. , Zorn M. , Haberland K. , Zettler J.‐T.
Published: September 2005

In this paper we will first report on the use of real‐time determination of wafer temperature for transparent substrates. With this method we will study the unintentional influence of growth parameter variations on the surface temperature. The effect on nitride growth optimization will be discussed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fast Padé transform for optimal quantification of time signals from magnetic resonance spectroscopy
Authors: Belkić Dževad , Belkić Karen
Published: September 2005

The fast Padé transform (FPT) is both a parametric and a nonparametric estimator that is capable of quantifying the input raw time signals without any fitting. The FPT simultaneously interpolates as well as extrapolates, and this is expected to mitigate truncation artifacts. To assess performance, it is necessary to compare the main features of the FPT with the characteristics of other parametric estimators, as well as with the fast Fourier transform (FFT), which can yield only shape spectra. The FPT can also give the shape of a spectrum, but accomplishes this in two totally different ways, with and without computing the spectral parameters (complex frequencies and amplitudes). A number of other parametric estimators used in signal processing are unable to yield shape spectra without prior extraction of the fundamental frequencies and the corresponding amplitudes. The primary goal of the present study is to assess the accuracy, robustness, and efficiency of the FPT for parametric and nonparametric estimations of experimentally measured time signals from in vivo magnetic resonance spectroscopy (MRS). Robustness and steadiness of the FPT are assessed relative to the FFT by monitoring the convergence rates of these two processors through a systematic and gradual decrease of the truncation level of the full signal length. Accuracy of the FPT is verified by performing error analysis of proven validity, using a gold standard, if available. Alternatively, comparison is made between the two complementary variants of the FPT that converge inside and outside the unit circle. Efficiency of the FPT is checked with respect to the FFT for estimation of the shape of a spectrum, as well as relative to other parametric processors, in the case of quantifications. To establish the accuracy, robustness, and efficiency of the FPT within the outlined multi‐level strategy, we use a time signal encoded via MRS at 4T from the brain of a healthy volunteer. We also assess the overall usefulness of the FPT for signal processing of data acquired from patients, in light of the emerging appreciation that spectroscopy of the tissue metabolites offers a number of vital advantages over the corresponding anatomical imaging in diagnostics. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Optimizing an ultrafast generic high‐performance liquid chromatography/tandem mass spectrometry method for faster discovery pharmacokinetic sample throughput
Authors: Dunn‐Meynell Kimberly W. , Wainhaus Samuel , Korfmacher Walter A.
Published: September 2005

For higher throughput screening, where the number of new chemical entities (NCEs) to test is rapidly increasing, fast sample turnaround time is essential. In order to increase efficiency a generic high‐performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) method, with a cycle time of 85 s (42 injections/h), was created. This was accomplished through the use of a 1‐min ballistic gradient and the optimization of the autosampler. The gradient was optimized by varying the organic mobile phase concentration and examining its ballistic characteristics with respect to matrix ion suppression and compound retention time. The autosampler time could be reduced by optimizing several parameters and by determining the source of most of the carryover in order to reduce the number of syringe and injector washes. Finally, the reliability of the new generic method is demonstrated by comparison of sample data with a standard 2‐min linear gradient method that showed that the data sets were well correlated. For plasma AUC (ng.h/mL) of 28 NCEs, the regression line had a slope of 0.92 and the R2 was 0.929. The described method was found to be useful for both rat plasma and tissue samples. Copyright © 2005 John Wiley & Sons, Ltd.
MDR‐like ABC transporter AtPGP4 is involved in auxin‐mediated lateral root and root hair development
Authors: Santelia Diana , Vincenzetti Vincent , Azzarello Elisa , Bovet Lucien , Fukao Yoichiro , Düchtig Petra , Mancuso Stefano , Martinoia Enrico , Geisler Markus
Published: September 2005

Here we show that related isoform AtPGP4 is expressed predominantly during early root development. AtPGP4 loss‐of‐function plants reveal enhanced lateral root initiation and root hair lengths both known to be under the control of auxin. Further, atpgp4 plants show altered sensitivities toward auxin and the auxin transport inhibitor, NPA. Finally, mutant roots reveal elevated free auxin levels and reduced auxin transport capacities. These results together with yeast growth assays suggest a direct involvement of AtPGP4 in auxin transport processes controlling lateral root and root hair development.
Identification of conserved histidines and glutamic acid as key residues for isomerohydrolase activity of RPE65, an enzyme of the visual cycle in the retinal pigment epithelium
Authors: Takahashi Yusuke , Moiseyev Gennadiy , Chen Ying , Ma Jian-xing
Published: September 2005

We have recently reported that RPE65 from the retinal pigment epithelium is the isomerohydrolase, a critical enzyme in the visual cycle for regeneration of 11‐cis retinal, the chromophore for visual pigments. Here, we demonstrated that mutation of any one of the absolutely conserved four histidine and one glutamic acid residues to alanine in RPE65 abolished its isomerohydrolase activity. Substitution of the conserved glutamic acid with glutamine also resulted in loss of the activity. Moreover, these mutations significantly reduced protein stability of RPE65. These results indicate that these conserved residues are essential for the isomerohydrolase activity of RPE65 and its stability.
language planning in malaysia: the first hundred years
Authors: hassan abdullah
Published: September 2005

recent developments in malaysia have brought forth many issues vis-à-vis language planning, notably including the return to english as a medium of instruction. the present review addresses current linguistic issues and their implications for malay as the national official language, bringing together linguistics, sociology, education, psychology, communication, geography, history, politics, finance and management, in a nation which is not only multilingual but also multiethnic, multi-religious and multicultural. to make the matter more complex still, the immigrant population is almost as large as the so-called indigenous ‘majority’.
teaching and using english in hong kong, china, and the world
Authors: mcarthur tom
Published: September 2005

there are, as it were, three levels in the title
of the discussion, each going further ‘out’ from
hong kong, although the direction and perspective
could as easily have been reversed,
moving ‘inwards’ from the world to china to
hong kong, one of history's most successful
social, cultural, political, and economic anomalies.
there could equally easily have been four
levels: hong kong, china, asia, and the world,
a framework that would even then have been
simpler than, say, ‘london, england, the
united kingdom, the european union, europe
at large, and the world’, but much the same as
‘lagos, nigeria, africa, and the world’ or ‘los
angeles, california, the united states, and the
world’.
Termitaria are focal feeding sites for large ungulates in Lake Mburo National Park, Uganda
Authors: Mobæk Ragnhild , Narmo Anne Kjersti , Moe Stein R.
Published: September 2005

In constructing large vegetated mounds,Macrotermestermites play a key functional role in many African savanna systems. This study focuses on ungulate feeding onMacrotermestermitaria vegetation in Lake Mburo National Park, Uganda. With the exception of oribiOurebia ourebi, all the species studied (i.e. impalaAepyceros melampus, Burchell's zebraEquus burchelli, Defassa waterbuckKobus ellipsiprymnus, topiDamaliscus lunatus, bushbuckTragelaphus scriptusand warthogPhacochoerus africanus) grazed preferentially on mound areas compared to the adjacent savanna. Ruminant species grazed closer to termitaria than non‐ruminants and female impala both browsed and grazed closer to mounds than males. No sexual difference in grazing distance to mounds was found for waterbuck.
Changes in causes of sudden deaths by decade in patients with coronary arterial lesions due to Kawasaki disease
Authors: Tsuda Etsuko , Arakaki Yoshio , Shimizu Toshio , Sakaguchi Heima , Yoshimura Shinichiro , Yazaki Satoshi , Echigo Shigeyuki
Published: September 2005

Over a 25-year period, we encountered 12 patients who died suddenly with coronary arterial lesions due to Kawasaki disease. We report their clinical course, and analyze the happenings of their deaths. Of the 12 patients, 10 were dead on arrival at hospital. Their age at death ranged from 13 months to 27 years, with a median of 16 years, and the interval from the onset of Kawasaki disease to death ranged from 2 months to 24 years. In 4 patients, death was found to be due to myocardial infarction, while in the remaining 8, it could not be determined. In 7 patients, coronary angiograms obtained less than 4 months after the acute onset of Kawasaki disease showed lesions bilaterally, most being giant aneurysms. Myocardial infarction had occurred in 6 patients prior to their death. In 1 patient of the late 1970s, who collapsed after running, cardiac sequels had not been suspected prior to autopsy. During the 1980s, 3 infants with bilateral giant aneurysms died within a year of the initial onset of Kawasaki disease, with acute myocardial infarction being the cause in 2 of them. In the late 1990s, and the 2000s, 5 patients died suddenly with left ventricular dysfunction, their ejection fractions being less than 40 percent more than 20 years after the initial onset of Kawasaki disease. Prior to their sudden deaths, they had had no cardiac events for many years, but had suffered previous myocardial infarctions. Multifocal premature ventricular contractions, and non-sustained ventricular tachycardia, are probable risk factors in such patients. Careful follow-up, checking for ventricular arrhythmia, is needed to prevent sudden death in patients suffering left ventricular dysfunction in the setting of Kawasaki disease.
Hybrid approach to severe coarctation and aortic regurgitation
Authors: Teixeira Ana M. , Reis-Santos Katya , Anjos Rui
Published: September 2005

Aortic coarctation is occasionally detected only in adulthood, usually in the context of systemic hypertension. It is frequently associated with other malformations, but the presence of severe disease of the aortic or mitral valves is rare. Such associated lesions, nonetheless, have important implications regarding the type and timing of therapeutic interventions. We describe an adult patient with severe aortic coarctation, aortic valvar regurgitation, and impaired left ventricular systolic function. We treated the aortic coarctation first by means of percutaneous dilation and implantation of a stent. Four days later, we proceeded to treat the aortic regurgitation surgically, using the Bentall procedure. Our experience documents a safe and efficient therapeutic approach to this association of lesions.
Fatal dissection of the descending aorta after implantation of a stent in a 19-year-old female with Turner's syndrome
Authors: Fejzic Zina , van Oort Anton
Published: September 2005

We report a fatal dissection of the descending aorta as a complication after a two-staged implantation of a stent to relieve aortic coarctation in a young female with Turner's syndrome. Implantation of the stent, with dilation up to 70 percent, and half a year later re-dilation to 100 percent, was without any complication. A week after the re-dilation, however, the patient suffered acute dissection of the descending aorta. We initially stabilized the situation, but some days later her condition deteriorated, and she died. We discuss the various options for treating coarctation and re-coarctation. As far as we know, this is the first description of implantation of a stent in the setting of coarctation in Turner's syndrome, albeit with an unfortunate conclusion.
Extreme solar‐terrestrial events of October 2003: High‐latitude and Cluster observations of the large geomagnetic disturbances on 30 October
Authors: Rosenqvist L. , Opgenoorth H. , Buchert S. , McCrea I. , Amm O. , Lathuillere C.
Published: September 2005

The extremely large solar eruption on 28 October 2003 caused an intense geomagnetic storm at Earth. A second solar eruption on 29 October resulted in a reintensification of the storm about a day later. Similarities and differences between these two events in terms of solar eruption, solar wind driver, and their resulting effect on the near‐Earth environment are investigated and put into context of previous works on storm geoeffectivness. Within the second storm some of the strongest substorms in the history of magnetic recordings occurred in northern Scandinavia. The aim of this study is to investigate the cause and resulting effects of these extreme geomagnetic disturbances on the ionosphere and upper atmosphere, focusing on the northern Scandinavian sector where these disturbances reached extremely high values. During this time period, well after the initial arrival of the Interplanetary Coronal Mass Ejection (ICME), the Cluster spacecraft were located at the flank of the magnetospheric tail. The satellites were passed several times by an inward and consecutively outward moving magnetopause in close relation to the substorm intensifications in northern Scandinavia. We propose that the evolution of these magnetospheric substorm intensifications are influenced by the changing dynamics of the solar wind in the form of increased pressure occurring after a prolonged period of southward Interplanetary Magnetic Field (IMF) and thus excessive energy loading into the magnetosphere prior to the onset of the intensifications. We present evidence of external pressure pulse triggering and possibly also quenching of these substorm onsets and recoveries. In addition, EISCAT data have been used to investigate the detailed local behavior of the ionospheric plasma, giving rise to such extreme disturbances. We found that in this case, extreme combinations of enhanced conductivity and intense electric field resulted in very high current intensities (westward electrojet ∼7.4 MA) and very fast onset of such currents. The associated geomagnetically induced currents caused power failures in southern Sweden.
Coastal ocean response to summer upwelling favorable winds in a region of alongshore bottom topography variations off Oregon
Authors: Castelao Renato M. , Barth John A.
Published: September 2005

Repeated mesoscale surveys of waters over the shelf and slope off Oregon were conducted during spring and summer of 2001 to study the spatial structure of the velocity and hydrographic fields. The ocean response to wind forcing is compared between a region of relatively simple topography with alongshore uniformity and a region of complex topography including a shallow submarine bank (Heceta Bank). In the simple topography region the upper water column is influenced by upwelling and fresh water from the Columbia River during spring, with the low‐salinity water located farther offshore during summer. Variability in the fields is mostly confined within 30 km from the coast. Over Heceta Bank the region of higher variability is broader, spanning most of the shelf. The coastal upwelling jet is located inshore of the pinnacle of the bank during spring, moving offshore during summer. The region inshore of the bank is characterized by low velocities and flow recirculation. Near‐surface fields show that the circulation evolves considerably between seasons. In both regions the area influenced by upwelled water is much broader during summer. Dense waters found over midshelf off Newport are upwelled to the north and advected south. Dense waters inshore of Heceta Bank are substantially influenced by water from the north during spring, but their source is mostly from the south during summer. South of the bank, the separation of the jet significantly increases the cross‐isobath transport, constituting an efficient mechanism for transport of material from the shelf into deeper waters.
Yeast caspase 1 links messenger RNA stability to apoptosis in yeast
Authors: Mazzoni Cristina , Herker Eva , Palermo Vanessa , Jungwirth Helmut , Eisenberg Tobias , Madeo Frank , Falcone Claudio
Published: September 2005

During the past years, yeasts have been successfully established as models to study the mechanisms of apoptotic regulation. We recently showed that mutations in the LSM4 gene, which is involved in messenger RNA decapping, lead to increased mRNA stability and apoptosis in yeast. Here, we show that mitochondrial function and YCA1, which encodes a budding yeast metacaspase, are necessary for apoptosis triggered by stabilization of mRNAs. Deletion of YCA1 in yeast cells mutated in the LSM4 gene prevents mitochondrial fragmentation and rapid cell death during chronological ageing of the culture, diminishes reactive oxygen species accumulation and DNA breakage, and increases resistance to H2O2 and acetic acid. mRNA levels in lsm4 mutants deleted for YCA1 are still increased, positioning the Yca1 budding yeast caspase as a downstream executor of cell death induced by mRNA perturbations. In addition, we show that mitochondrial function is necessary for fast death during chronological ageing, as well as in LSM4 mutated and wild‐type cells.
Yersinia pestis kills Caenorhabditis elegans by a biofilm‐independent process that involves novel virulence factors
Authors: Styer Katie L , Hopkins Gregory W , Bartra Sara Schesser , Plano Gregory V , Frothingham Richard , Aballay Alejandro
Published: September 2005

It is known that Yersinia pestis kills Caenorhabditis elegans by a biofilm‐dependent mechanism that is similar to the mechanism used by the pathogen to block food intake in the flea vector. Using Y. pestis KIM5, which lacks the genes that are required for biofilm formation, we show that Y. pestis can kill C. elegans by a biofilm‐independent mechanism that correlates with the accumulation of the pathogen in the intestine. We used this novel Y. pestis–C. elegans pathogenesis system to show that previously known and unknown virulence‐related genes are required for full virulence in C. elegans. Six Y. pestis mutants with insertions in genes that are not related to virulence before were isolated using C. elegans. One of the six mutants carried an insertion in a novel virulence gene and showed significantly reduced virulence in a mouse model of Y. pestis pathogenesis. Our results indicate that the Y. pestis–C. elegans pathogenesis system that is described here can be used to ide.jpgy and study previously uncharacterized Y. pestis gene products required for virulence in mammalian systems.
The c15 ring of the Spirulina platensis F‐ATP synthase: F1/F0 symmetry mismatch is not obligatory
Authors: Pogoryelov Denys , Yu Jinshu , Meier Thomas , Vonck Janet , Dimroth Peter , Muller Daniel J
Published: September 2005

The oligomeric c ring of the F‐ATP synthase from the alkaliphilic cyanobacterium Spirulina platensis was isolated and characterized. Mass spectroscopy analysis indicated a mass of 8,210 Da, reflecting that of a c monomer. The mass increased by 206 Da after treatment with the c‐subunit‐specific inhibitor dicyclohexylcarbodiimide (DCCD), which indicated modification of the ion‐binding carboxylate by DCCD. Atomic force microscopy topographs of c rings from S. platensis showed 15 symmetrically assembled subunits. The c15‐mer reported here is the largest c ring that is isolated and does not show the classical c‐ring mismatch to the three‐fold symmetry of the F1 domain.
A pre‐anaphase role for a Cks/Suc1 in acentrosomal spindle formation of Drosophila female meiosis
Authors: Pearson Neil J , Cullen C Fiona , Dzhindzhev Nikola S , Ohkura Hiroyuki
Published: September 2005

Conventional centrosomes are absent from a female meiotic spindle in many animals. Instead, chromosomes drive spindle assembly, but the molecular mechanism of this acentrosomal spindle formation is not well understood. We have screened female sterile mutations for defects in acentrosomal spindle formation in Drosophila female meiosis. One of them, remnants (rem), disrupted bipolar spindle morphology and chromosome alignment in non‐activated oocytes. We found that rem encodes a conserved subunit of Cdc2 (Cks30A). As Drosophila oocytes arrest in metaphase I, the defect represents a new Cks function before metaphase–anaphase transition. In addition, we found that the essential pole components, Msps and D‐TACC, were often mislocalized to the equator, which may explain part of the spindle defect. We showed that the second cks gene cks85A, in contrast, has an important role in mitosis. In conclusion, this study describes a new pre‐anaphase role for a Cks in acentrosomal meiotic spindle formation.
An RNA interference screen ide.jpgies Inhibitor of Apoptosis Protein 2 as a regulator of innate immune signalling in Drosophila
Authors: Gesellchen Viola , Kuttenkeuler David , Steckel Michael , Pelte Nadège , Boutros Michael
Published: September 2005

Innate immunity in vertebrates and invertebrates is of central importance as a biological programme for host defence against pathogenic challenges. To find novel components of the Drosophila immune deficiency (IMD) pathway in cultured haemocyte‐like cells, we screened an RNA interference library for modifiers of a pathway‐specific reporter. Selected modifiers were further characterized using an independent reporter assay and placed into the pathway in relation to known pathway components. Interestingly, the screen ide.jpgied the Inhibitor of Apoptosis Protein 2 (IAP2) as being required for IMD signalling. Whereas loss of DIAP1, the other member of the IAP protein family in Drosophila, leads to apoptosis, we show that IAP2 is dispensable for cell viability in haemocyte‐like cells. Cell‐based epistasis experiments show that IAP2 acts at the level of Tak1 (transforming growth factor‐β‐activated kinase 1). Our results indicate that IAP gene family members may have acquired other functions, such as the regulation of the tumour necrosis factor‐like IMD pathway during innate immune responses.
Structures and adsorption of binary hard-core Yukawa mixtures in a slitlike pore: Grand canonical Monte Carlo simulation and density-functional study
Authors: You Feng-Qi , Yu Yang-Xin , Gao Guang-Hua
Published: September 2005

The grand canonical ensemble Monte Carlo simulation and density-functional theory are applied to calculate the structures, local mole fractions, and adsorption isotherms of binary hard-core Yukawa mixtures in a slitlike pore as well as the radial distribution functions of bulk mixtures. The excess Helmholtz energy functional is a combination of the modified fundamental measure theory of Yu and Wu [J. Chem. Phys. 117, 10156 (2002)] for the hard-core contribution and a corrected mean-field theory for the attractive contribution. A comparison of the theoretical results with the results from the Monte Carlo simulations shows that the corrected theory improves the density profiles of binary hard-core Yukawa mixtures in the vicinity of contact over the original mean-field theory. Both the present corrected theory and the simulations suggest that depletion and desorption occur at low temperature, and the local segregation can be observed in most cases. For binary mixtures in the hard slitlike pore, the present corrected theory predicts more accurate surface excesses than the original one does, while in the case of the attractive pore, no improvement is found in the prediction of a surface excess of the smaller molecule.
Laser cooling of vibrational degrees of freedom of a molecular system
Authors: Banerjee Sumana , Gangopadhyay Gautam
Published: September 2005

We consider the cooling of vibrational degrees of freedom in a photoinduced excited electronic state of a model molecular system. For the various parameters of the potential surfaces of the ground and excited electronic states and depending on the excitation frequency of a single-mode laser light, the average energy or average vibrational temperature of the excited state passes through a minimum. The amount of cooling is quantified in terms of the overlap integral between the ground and excited electronic states of the molecule. We have given an approach to calculate the Franck-Condon factor for a multimode displaced-distorted-rotated oscillator surface of the molecular system. This is subsequently used to study the effect of displacement, distortion, and Duschinsky rotation on the vibrational cooling in the excited state. The absorption spectra and also the average energy or the effective temperature of the excited electronic state are studied for the above model molecular system. Considering the non-Condon effect for the symmetry-forbidden transitions, we have discussed the absorption spectra and average temperature in the excited-state vibrational manifold.
Direct computation of characteristic temperatures and relaxation times for glass-forming polymer liquids
Authors: Dudowicz Jacek , Freed Karl F. , Douglas Jack F.
Published: September 2005

Characteristic temperatures and structural relaxation times for different classes of glass-forming polymer liquids are computed using a revised entropy theory of glass formation that permits the chain backbone and the side groups to have different rigidities. The theory is applied to glass formation at constant pressure or constant temperature. Our calculations provide new insights into physical factors influencing the breadth of the glass transition and the associated growth of relaxation times.
Abnormal hole mobility of biaxial strained Si
Authors: Liao M. H. , Chang S. T. , Lee M. H. , Maikap S. , Liu C. W.
Published: September 2005

The strain effect on the hole mobility is investigated by bulk Si field-effect transistor, substrate-strained Si devices, and these devices under biaxial tensile mechanical strain. The hole mobility along ⟨110⟩ direction on (001) Si substrate degrades at small biaxial tensile strain (<∼0.3%) but enhances at the biaxial tensile strain larger than ∼0.3%. This abnormal behavior can be understood in terms of the effective hole conductive mass which is the population average of heavy-hole and light-hole masses. The effective mass is more heavy-hole-like at small strain, since the heavy-hole band has a larger density of state than light-hole band. As the biaxial tensile strain increases, the hole population in the light-hole band increases due to the upshift and crossover of the light-hole band above the heavy-hole band. Therefore, the effective mass with larger biaxial tensile strain decreases significantly due to the small mass of light hole. The effective hole mass, which increases at small strain, then decreases at large strain, is responsible to the abnormal hole mobility behavior.
A near-room-temperature all-optical polarization switch based on the excitation of spin-polarized “virtual” carriers in quantum wells
Authors: Yildirim Murat , Prineas J. P. , Gansen Eric J. , Smirl Arthur L.
Published: September 2005

Near-room-temperature operation of an all-optical polarization switch based on the virtual excitation of spin-polarized carriers in semiconductor quantum wells is demonstrated. The device is shown to exhibit a pulse-width-limited switching time, a contrast ratio of >18dB, an optical bandwidth of ∼3THz, and an energy throughput of >0.1% using a thin (40 wells) GaAs∕AlGaAs sample. The results of differential transmission measurements are used to identify the dominant switching mechanisms and to monitor the spin and temporal dynamics of the carriers excited during the operation of the switch.
Measurement of light emission in scintillation vials
Authors: Durán Ramiro M. Teresa , García-Toraño Eduardo
Published: September 2005

The efficiency and energy resolution of liquid scintillation counting (LSC) systems are strongly dependent on the optical characteristics of scintillators, vials, and reflectors. This article presents the results of measurements of the light-emission profile of scintillation vials. Two measurement techniques, autoradiographs and direct measurements with a photomultiplier tube, have been used to obtain light-emission distribution for standard vials of glass, etched glass and polyethylene. Results obtained with both techniques are in good agreement. For the first time, the effect of the meniscus in terms of light contribution has been numerically estimated. These results can help design LSC systems that are more efficient in terms of light collection.
Band gap reduction in GaNSb alloys due to the anion mismatch
Authors: Veal T. D. , Piper L. F. J. , Jollands S. , Bennett B. R. , Jefferson P. H. , Thomas P. A. , McConville C. F. , Murdin B. N. , Buckle L. , Smith G. W. , Ashley T.
Published: September 2005

The structural and optoelectronic properties in GaNxSb1−x alloys (0⩽x<0.02) grown by molecular-beam epitaxy on both GaSb substrates and AlSb buffer layers on GaAs substrates are investigated. High-resolution x-ray diffraction (XRD) and reciprocal space mapping indicate that the GaNxSb1−x epilayers are of high crystalline quality and the alloy composition is found to be independent of substrate, for identical growth conditions. The band gap of the GaNSb alloys is found to decrease with increasing nitrogen content from absorption spectroscopy. Strain-induced band-gap shifts, Moss-Burstein effects, and band renormalization were ruled out by XRD and Hall measurements. The band-gap reduction is solely due to the substitution of dilute amounts of highly electronegative nitrogen for antimony, and is greater than observed in GaNAs with the same N content.
Quantum dot formation on a strain-patterned epitaxial thin film
Authors: Wise S. M. , Lowengrub J. S. , Kim J. S. , Thornton K. , Voorhees P. W. , Johnson W. C.
Published: September 2005

We model the effect of substrate strain patterning on the self-assembly of quantum dots (QDs). When the surface energy is isotropic, we demonstrate that strain patterning via embedded substrate inclusions may result in ordered, self-organized QD arrays. However, for systems with strong cubic surface energy anisotropy, the same patterning does not readily lead to an ordered array of pyramids at long times. We conclude that the form of the surface energy anisotropy strongly influences the manner in which QDs self-assemble into regular arrays.
Cell entry mechanism of enzymatic bacterial colicins: Porin recruitment and the thermodynamics of receptor binding
Authors: Housden Nicholas G. , Loftus Steven R. , Moore Geoffrey R. , James Richard , Kleanthous Colin
Published: September 2005

Binding of enzymatic E colicins to the vitamin B
12
receptor, BtuB, is the first stage in a cascade of events that culminate in the translocation of the cytotoxic nuclease into the
Escherichia coli
cytoplasm and release of its tightly bound immunity protein. A dogma of colicin biology is that the toxin coiled-coil connecting its functional domains must unfold or unfurl to span the periplasm, with recent reports claiming this reaction is initiated by receptor binding. We report isothermal titration calorimetry data of BtuB binding the endonuclease toxin ColE9 and a disulfide form (ColE9
S-S
) where unfolding of the coiled-coil is prevented and, as a consequence, the toxin is biologically inactive. Contrary to expectation, the thermodynamics of receptor binding, characterized by large negative values for TΔS, are identical for the two colicins, arguing against any form of BtuB-induced unfolding. We go on to delineate key features of the “colicin translocon” that assembles at the cell surface after BtuB binding by using a complex of histidine-tagged Im9 bound to ColE9
S-S
. First, we show that the porin OmpF is recruited directly to the BtuB·colicin complex to form the translocon. Second, recruitment is through the natively unfolded region of the colicin translocation domain, with this domain likely having two contact points for OmpF. Finally, the immunity protein is not released during its assembly. Our study demonstrates that although colicin unfolding is undoubtedly a prerequisite for
E. coli
cell death, it must occur after assembly of the translocon.
The x-ray crystal structure of lysine-2,3-aminomutase from
Clostridium subterminale
Authors: Lepore Bryan W. , Ruzicka Frank J. , Frey Perry A. , Ringe Dagmar
Published: September 2005

The x-ray crystal structure of the pyridoxal-5′-phosphate (PLP),
S
-adenosyl-
l
-methionine (SAM), and [4Fe–4S]-dependent lysine-2,3-aminomutase (LAM) of
Clostridium subterminale
has been solved to 2.1-Å resolution by single-wavelength anomalous dispersion methods on a
l
-selenomethionine-substituted complex of LAM with [4Fe–4S]
2+
, PLP, SAM, and
l
-α-lysine, a very close analog of the active Michaelis complex. The unit cell contains a dimer of hydrogen-bonded, domain-swapped dimers, the subunits of which adopt a fold that contains all three cofactors in a central channel defined by six β/α structural units. Zinc coordination links the domain-swapped dimers. In each subunit, the solvent face of the channel is occluded by an N-terminal helical domain, with the opposite end of the channel packed against the domain-swapped subunit. Hydrogen-bonded ionic contacts hold the external aldimine of PLP and
l
-α-lysine in position for abstraction of the 3-pro-
R
hydrogen of lysine by C5′ of SAM. The structure of the SAM/[4Fe–4S] complex confirms and extends conclusions from spectroscopic studies of LAM and shows selenium in Se-adenosyl-
l
-selenomethionine poised to ligate the unique iron in the [4Fe–4S] cluster upon electron transfer and radical formation. The chain fold in the central domain is in part analogous to other radical–SAM enzymes.
miR-15
and
miR-16
induce apoptosis by targeting BCL2
Authors: Cimmino Amelia , Calin George Adrian , Fabbri Muller , Iorio Marilena V. , Ferracin Manuela , Shimizu Masayoshi , Wojcik Sylwia E. , Aqeilan Rami I. , Zupo Simona , Dono Mariella , Rassenti Laura , Alder Hansjuerg , Volinia Stefano , Liu Chang-gong , Kipps Thomas J. , Negrini Massimo , Croce Carlo M.
Published: September 2005

Chronic lymphocytic leukemia (CLL) is the most common human leukemia and is characterized by predominantly nondividing malignant B cells overexpressing the antiapoptotic B cell lymphoma 2 (Bcl2) protein.
miR-15a
and
miR-16-1
are deleted or down-regulated in the majority of CLLs. Here, we demonstrate that
miR-15a
and
miR-16-1
expression is inversely correlated to Bcl2 expression in CLL and that both microRNAs negatively regulate Bcl2 at a posttranscriptional level. BCL2 repression by these microRNAs induces apoptopsis in a leukemic cell line model. Therefore,
miR-15
and
miR-16
are natural antisense Bcl2 interactors that could be used for therapy of Bcl2-overexpressing tumors.
Design of a “green” one-step catalytic production of ε-caprolactam (precursor of nylon-6)
Authors: Thomas John Meurig , Raja Robert
Published: September 2005

The ever-increasing industrial demand for nylon-6 (polycaprolactam) necessitates the development of environmentally benign methods of producing its precursor, ε-caprolactam, from cyclohexanone. It is currently manufactured in two popular double-step processes, each of which uses highly aggressive reagents, and each generates substantial quantities of largely unwanted ammonium sulfate as by-product. Here we describe a viable laboratory-scale, single-step, solvent-free process of producing ε-caprolactam using a family of designed bifunctional, heterogeneous, nanoporous catalysts containing isolated acidic and redox sites, which smoothly convert cyclohexanone to ε-caprolactam with selectivities in the range 65–78% in air and ammonia at 80°C. The catalysts are microporous (pore diameter 7.3 Å) aluminophosphates in which small fractions of the

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\begin{equation*}{\mathrm{Al}}^{{\mathrm{III}}}{\mathrm{O}}_{4}^{5-}\end{equation*}\end{document}

and

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\begin{equation*}{\mathrm{P}}^{{\mathrm{V}}}{\mathrm{O}}_{4}^{3-}\end{equation*}\end{document}

tetrahedra constituting the 4-connected open framework are replaced by

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\begin{equation*}{\mathrm{Co}}^{{\mathrm{III}}}{\mathrm{PO}}_{4}^{5-}\end{equation*}\end{document}

and

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\begin{equation*}{\mathrm{Si}}^{{\mathrm{IV}}}{\mathrm{O}}_{4}^{4-}\end{equation*}\end{document}

tetrahedra, which become the loci of the redox and acidic centers, respectively. The catalysts may be further optimized, and already may be so designed as to generate selectivities of ≈80% for the intermediate oxime, formed from NH
2
OH, which is produced
in situ
within the pore system. The advantages of such designed heterogeneous catalysts, and their application to a range of other chemical conversions, are also adumbrated.
Nitrogen metabolism in the reticule-rumen of steers on diets containing extracted soya-bean meal and infrared-toasted soya beans
Authors: Stallcup O. T. , Davis G. V.
Published: September 2005

1. Diets containing cottonseed hulls and flaked infrared-toasted soya beans, cottonseed hulls and soya-bean meal or cottonseed hulls alone were fed to three fistulated steers. 2. The diet containing toasted soya-bean flakes was associated with the highest concentrations of total nitrogen, protein N, and ammonia N in the rumen liquor; the diet of cottonseed hulls was associated with the lowest concentrations; and soya-bean meal was associated with intermediate concentrations. 3. Concentrations of residual N were highest in rumen liquor during the first 3 h after feeding when soya-bean meal was given and highest with the other diets between 10 and 12 h after feeding; concentrations of non-protein N were highest with the toasted soya-bean flakes at all times except approximately 2 h after feeding when they were highest with soya-bean meal. 4. The rumen liquor was more acid with soya-bean flakes than with the other diets. 5. The total concentration of volatile fatty acids (m-moles/100 ml) was highest with the diet containing toasted soya-bean flakes, followed by that with soya-bean meal and cottonseed hulls and lowest with the cottonseed-hull diet. The molar percentage of acetic acid was highest with soya-bean meal, whereas its concentration (m-moles/100 ml) was highest with soya-bean flakes. Propionic acid concentrations were highest with the toasted soya-bean flakes. 6. These results indicate that the metabolism in the reticulo- rumen of infrared-toasted whole soya beans given as flakes differs from that of soya-bean meal.
The metabolism of oleic, linoleic and linolenic acids by sheep with reference to their effects on methane production
Authors: Czerkawski J. W. , Blaxter K. L. , Wainman F. W.
Published: September 2005

1. Nine experiments, each with one of six sheep with cannulated rumens given a constant diet of dried grass, were made in which oleic, linoleic or linolenic acid was infused into the rumen and energy and lipid metabolism were measured. One experiment was made in which palmitic acid was given. 2. Judged by changes in the composition of isolated fatty acids, the unsaturated fatty acids were hydrogenated in the rumen. An increase in the excretion of lipid in the faeces occurred when the unsaturated acids were given. The heat of combustion of the faeces increased by 12.6±3.0 kcal/100 kcal fatty acid, of which 94% was accounted for by the additional lipid. 3. Methane production fell when the unsaturated fatty acids were infused, the decreases being 13.8±1.6 kcal CH4;/I00 kcal oleic acid, 14.2±1.5 kcal CH4/100 kcal linoIeic acid and 16.4±1.3 kcal CH4/100 kcal Iinolenic acid. The introduction of a double bond into an n-alkyl acid was calculated to reduce methane production by 0.24±0.09 moles/mole double bond. 4. Because the depression of methane production on infusing the fatty acids exceeded the increase in the heat of combustion of the faeces, the metabolizable energy of the fatty acids was 104.1±5.3% of their heat of combustion. 5. The efficiencies with which the fatty acids were used to promote energy retention were 74.6±5.7% for oleic acid, 79.2±2.0 % for linoleic acid and 82.5±3.0% for linolenic acid. These efficiencies agreed with those noted in experiments by others with rats, horses and pigs given glycerides, but were higher than those noted by others when glycerides were added to the diets of ruminants.
Binding of magnesium and calcium in the contents of the small intestine of the calf
Authors: Smith R. H. , McAllan A. B.
Published: September 2005

1. In ileal contents from differently fed ruminating calves, examined under conditions approximating to those obtaining in vivo, 34–74% of the magnesium and 63–93% of the calcium were non-ultrafilterable. The binding was shown to be due to at least two processes, one depending on the presence of phosphate, the other not. 2. Considerable non-phosphate binding occurred in samples adjusted in vitro to pH 5.5 and above. The binding material was probably not a single substance but the bound forms of both Mg and Ca were, at least partly, in equilibrium with the soluble forms, and some competition between the two metals occurred. Thus in any one sample the extent of binding for either metal was influenced by the concentration of both. With normal concentrations it was estimated that, in the ileum, about one-third of the Mg and half of the Ca was bound in this way, irrespective of whether pasture or one of a variety of stall diets was given. 3. Samples adjusted to about pH 6.5 and above (in vivo ileum pH was about 7.4–7.9) showed further precipitation of Ca and Mg to an extent which partly depended on the concentration of inorganic phosphate. Ca precipitation appeared to be mainly controlled by the concentration of Ca and inorganic phosphate but for Mg the precipitation depended also on the presence of factors other than Mg and inorganic phosphate. One such factor found to be present was the ammonium ion, but its practical importance is uncertain. 4. Ileal contents from milk-fed calves showed considerable non-phosphate binding of Ca but not of Mg.
Studies on the composition of food
Authors: Chamberlain N. , Collins T. H , Elton G. A. H , Hollingsworth Dorothy F , Lisle D. B , Payne P. R
Published: September 2005

1. The Chorleywood Bread Process is a new method of making bread in which the 2–4 h of bulk fermentation of the dough normal in breadmaking is replaced by a few minutes of intense mechanical agitation to a controlled degree in special high-speed mixers. It is now being used to make over 30% of British bread. 2. Bread was made in a commercial bakery from two white flours by the Chorleywood Bread Process and a conventional method. 3. Both the bread and flours were analysed for moisture, protein, ash, fat, carbohydrate (by difference), thiamine, nicotinic acid and ascorbic acid. 4. More bread was made by the two processes from two other flours in a pilot-scale bakery. These breads and flours were used to determine net protein utilization values. 5. It was concluded that bread made by the Chorleywood Process cannot be distinguished from conventional bread in its content of protein, fat, ash and nicotinic acid, and in protein quality as indicated by its net protein utilization value. This was true for two grades of flour. In these tests the contents of thiamine and moisture were slightly higher and of carbohydrate slightly lower in Chorleywood than in conventional bread. No ascorbic or dehydroascorbic acid could be detected in any of the bread.
The short-term prognosis of severe primary infantile malnutrition
Authors: Garrow J. S. , Pike M. C.
Published: September 2005

1. Among a series of 343 children with severe primary malnutrition there were 248 for whom, on admission, there were reliable records of age, weight, height, liver size, severity of oedema, skin lesions and angular stomatitis, and concentration of total serum protein, haemoglobin and sodium. For eighty-four of these children the serum bilirubin concentration was also known.

2. The correlations of these characteristics of the children on admission, with mortality, and with the rate of recovery were investigated.

3. Age, weight, oedema and haemoglobin concentration were not significantly related to mortality or to rate of recovery. A multiple regression analysis showed that an increased serum bilirubin concentration and a decreased serum sodium concentration indicated a bad prognosis, and these two factors contributed almost the whole of the multiple correlation coefficient of 0.63 with respect to mortality and 0.59 with respect to speed of rccovery.

4. We conclude that in our series of children death was more closely associated with liver failure or overhydration than with protein depletion, and suggest that the administration of ton much protein or water to an acutely ill malnourished child may precipitate death.

5. This analysis shows that the mortality observed in our series cannot be adequately explained by any combination of the characteristics considered above; there must, therefore, be other factors of importance for which we do not have suitable measurements.
Effects of vitamin E deficiency on total polyunsaturated fatty acids in rats and chicks
Authors: Bunyan J. , Diplock A. T. , Green J.
Published: September 2005

1. The total polyunsaturated fatty acid (PUFA) content of tissues of vitamin E-deficient rats and chicks has been measured by the lipoxidase method.

2. Vitamin E deficiency did not depress total PUFA in rat liver, kidney, heart, spleen, brain, adrenal and adipose tissue during experimental periods up to 13 months.

3. Liver PUFA was not depressed by deficiency of vitamin E and selenium in rats at 9 weeks or 8 months of age.

4. Rats given a muscular dystrophy-producing diet (containing oxidized cod-liver oil) showed a severe depletion of PUFA in muscle, but not in kidney or adipose tissue.

5. Exudative diathesis induced in chicks by a deficiency of vitamin E and Se did not depress liver PUFA.

6. It is considered that in vitamin E deficiency there is no general decrease in PUFA due to peroxidative loss. Changes of a more specific nature occur, as found by other workers.
Nitrogen balance studies with the milk-fed lamb
Authors: Walker D. M. , Cook L. J. , Jagusch K. T.
Published: September 2005

1. Thirty-three cross-bred lambs were given reconstituted dried whole cow's milk from 1 week of age at different levels of intake and at different frequencies of feeding.

2. Feeding frequency had no effect on live-weight gain, N retention or total body composition.

3. Lambs given two feeds daily had significantly heavier abomasums than pair-fed lambs given six feeds daily.

4. The weights of fat, protein (N x 6.25) and water in the body were closely related to empty body weight; body composition (% of empty body) was not significantly affected by the level of milk intake or by the rate of growth.

5. Live-weight gain was closely related to energy intake (r = +0.99) and to N retention (r = +0.97). A live-weight gain of 100 g was associated with an intake of 511 kcal and a N retention of 2.28 g N.