bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prenatal diagnosis of absent right and persistent left superior vena cava
Authors: Pasquini Lucia , Belmar Cristian , Seale Anna , Gardiner Helena M. 
Published: May 2006

AbstractObjectivePersistence of left superior vena cava (LSVC) is a known variant of the systemic venous return. In the setting of an otherwise structurally normal heart, absence of the right superior vena cava (RSVC) but persistence of the LSVC is rare.MethodsWe describe the prenatal findings of a fetus with absent right and persistent LSVC.ResultsA dichorionic diamniotic twin pregnancy was referred to our centre with cardiac disproportion. Twin A had disproportion at four‐chamber level, an absent right but persistent LSVC draining to an enlarged coronary sinus and a hypoplastic transverse aortic arch (<2 mm). Postnatal echocardiography of the asymptomatic baby confirmed the prenatal diagnosis, and serial echocardiograms demonstrated general hypoplasia of the aortic arch but no discrete coarctation (CoA). No intervention was required and the baby is thriving aged 10 months.ConclusionPersistence of LSVC is a known variant of the systemic venous return. In the setting of an otherwise structurally normal heart, absence of the right but persistence of LSVC is rare. Copyright © 2006 John Wiley & Sons, Ltd.
First‐trimester examination of fetal nasal bone in the Chinese population
Authors: Chen Min , Lee Chin Peng , Tang Rebecca , Chan Ben , Ou Chun Quan , Tang Mary Hoi Yin 
Published: May 2006

AbstractObjectivesAbsence of the nasal bone in fetuses with trisomy 21 is a potential ultrasound marker for Down syndrome from the first trimester onwards. Racial differences in fetal nasal bone length have been reported. There was no reference range for the first‐trimester fetal nasal bone length (NBL) in the Chinese population.MethodsFrom January 2002 to February 2005, we investigated the reference range of NBL in 2169 singleton fetuses whose parents were Chinese with normal pregnancy outcome. Ultrasound measurements of NBL were performed on a midsagittal plane at 12–14 weeks' gestation.ResultsThe nasal bone length measurement showed a significant increase with gestational age (GA) (p < 0.05). A linear relationship between nasal bone length and gestational age (NBL = −3.3462 × GA + 0.627, R2 = 0.30, p < 0.001) as well as a linear relationship between nasal bone length and crown‐rump length (CRL) (NBL = 0.3741 × CRL + 0.284, R2 = 0.30, P < 0.001) was established.ConclusionThe measurement of nasal bone length was feasible in the first trimester. The reference range of NBL in normal Chinese fetuses in the first‐trimester of pregnancy was established. This formed a basis for further study on the use of fetal nasal bone measurement in the screening for aneuploidy in the Chinese population. Copyright © 2006 John Wiley & Sons, Ltd.
Endoscopy or colonoscopy guidelines for patients with diabetes
Authors: Wamae D , McHoy A 
Published: May 2006

AbstractLocal pilot guidelines for patients with diabetes undergoing an endoscopy or colonoscopy as an out‐patient were developed to reduce patient anxiety and the risk of hyperglycaemia and hypoglycaemia prior to and during their procedure. Audit was used as a tool to evaluate the guidelines.The audit highlighted that very few patients treated with insulin are prioritised to have their procedure early on the morning list.The results demonstrated that, of the 12 patients who normally experienced at least one hypoglycaemic episode (blood glucose <4mmol/L) a week, none reported an increase in hypoglycaemia experienced, and five patients had improved control. Of the 28 patients who did not normally experience at least one hypoglycaemic episode a week, all patients continued to be free from hypos. Of the six patients who normally experienced at least one hyperglycaemic episode (≥15mmol/L) a week, none reported an increase in the frequency of their hyperglycaemia, and two patients had improved control. Of the 34 patients who did not normally experience at least one hyperglycaemic episode a week, 32 patients reported no increase in the frequency of hyperglycaemia. However, two patients reported transient asymptomatic hyperglycaemia.The guidelines have assured standardisation of advice now given to patients, and enabled elective patients treated with insulin to be scheduled first on the morning list. Contact with a diabetes specialist nurse has enabled patients to access specialist advice regarding their general diabetes management that they would otherwise have not received. Copyright © 2006 John Wiley & Sons, Ltd.
Type 2 diabetes requiring insulin therapy precipitated by nicotinic acid in a patient with severe dyslipidaemia
Authors: Mukherjee S , Rees JAE 
Published: May 2006

AbstractThe insulin resistance syndrome may present with hyperinsulinaemia and dyslipidaemia prior to the onset of type 2 diabetes. Nicotinic acid is a lipid regulating agent, which is thought to exacerbate any underlying insulin resistance and may worsen glycaemic control. There is some controversy as to whether nicotinic acid has a clinically significant effect on glucose tolerance. We report a case whereby nicotinic acid precipitated type 2 diabetes requiring insulin therapy in a patient with severe dyslipidaemia and no previous history of diabetes. The mechanism of deterioration of insulin resistance by nicotinic acid is discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Novel metabolic drugs for the management of type 2 diabetes
Authors: Barnett AH , Bellary S 
Published: May 2006

AbstractThe prevalence of type 2 diabetes is dramatically increasing both in the UK and globally. This has led to a greater focus on the development of new and effective treatments and numerous agents are currently being investigated that target the metabolic processes underlying the disease. In this article, we focus on drugs that may particularly benefit the cardiometabolic, insulin resistance dysfunctions of type 2 diabetes. The peroxisome proliferator‐activated receptor (PPAR)‐γ is the target for the currently available anti‐diabetes drugs, rosiglitazone and pioglitazone. Agents that combine the potentially beneficial effects of activating both PPAR‐α and PPAR‐γ are also being developed and are known as the glitazars. Two of these agents, muraglitazar and tesaglitazar, are showing promise in Phase III trials. Activation of PPAR‐γ can be associated with weight gain and oedema, however, which may impact on patient compliance. The novel insulin sensitiser, metaglidasen, exhibits the insulin sensitising qualities of the thiazolidinediones, but does not appear to have the associated tolerability issues. Obesity, especially abdominal obesity, is a well known risk factor and is closely associated with the development of type 2 diabetes. The new cannabinoid receptor 1 (CB1) blocker, rimonabant, has been shown to have beneficial effects on abdominal obesity, dyslipidaemia and hyperglycaemia and so might be an effective treatment for abdominally obese patients with type 2 diabetes. The increasing impact of type 2 diabetes as a major health care concern necessitates that efforts are continued in developing agents that can provide increasing benefit for the effective management of this disease. Copyright © 2006 John Wiley & Sons, Ltd.
Use of fibrates in diabetes: what does the FIELD trial tell us?
Authors: Jowett NI 
Published: May 2006

AbstractFIELD was the largest cardiovascular prevention trial using fibrates in type 2 diabetes. Whilst the primary endpoint was not achieved, fenofibrate therapy associated with fewer non‐fatal myocardial infarctions and revascularisation procedures. Progress of renal and retinal microvascular disease appeared to be slowed. Although many patients were also taking statin therapy, FIELD does not provide evidence on efficacy or long‐term safety when co‐prescribed with fibrates. Statin monotherapy remains first line therapy for diabetic dyslipidaemia. Copyright © 2006 John Wiley & Sons, Ltd.
Bipyridinophane‐containing conjugated polymers modulated with an intramolecular aromatic CH/π interaction
Authors: Wang Wei‐Ling , Xu Jian‐Wei , Lai Yee‐Hing 
Published: May 2006

AbstractBipyridinophane–fluorene conjugated copolymers have been synthesized via Suzuki and Heck coupling reactions from 5,8‐dibromo‐2,11‐dithia[3]paracyclo[3](4,4′)‐2,2′‐bipyridinophane and suitable fluorene precursors. Poly[2,7‐(9,9‐dihexylfluorene)‐co‐alt‐5,8‐(2,11‐dithia[3]paracyclo[3](4,4′)‐2,2′‐bipyridinophane)] (P7) exhibits large absorption and emission redshifts of 20 and 34 nm, respectively, with respect to its planar reference polymer Poly[2,7‐(9,9‐dihexylfluorene)‐co‐alt‐1,4‐(2,5‐dimethylbenzene)] (P11), which bears the same polymer backbone as P7. These spectral shifts originate from intramolecular aromatic CH/π interactions, which are evidenced by ultraviolet–visible and 1H NMR spectra as well as X‐ray single‐crystal structural analysis. However, the effect of the intramolecular aromatic CH/π interactions on the spectral shift in poly[9,9‐dihexylfluorene‐2,7‐yleneethynylene‐co‐alt‐5,8‐(2,11‐dithia[3]paracyclo[3](4,4′)‐2,2′‐bipyridinophane)] (P10) is much weaker. Most interestingly, the quenching behaviors of these two conjugated polymers are largely dependent on the polymer backbone. For example, the fluorescence of P7 is efficiently quenched by Cu2+, Co2+, Ni2+, Zn2+, Mn2+, and Ag+ ions. In contrast, only Cu2+, Co2+, and Ni2+ ions can partially quench the fluorescence of P10, but much less efficiently than the fluorescence of P7. The static Stern–Volmer quenching constants of Cu2+, Co2+, and Ni2+ ions toward P7 are of the order of 106 M−1, being 1300, 2500, and 37,300 times larger than those of P10, respectively. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4154–4164, 2006
Calorimetric investigation of the interaction of carbon nanotubes with polystyrene
Authors: Rivin D. , Suzin Y. 
Published: May 2006

AbstractA simple, scalable procedure that does not require covalent modification of the filler or specialized high shear mixers is described for preparing well‐dispersed carbon nanotube composites. Excellent particle dispersions of multiple‐walled carbon nanotubes (NTs) and carbon black (CB) in polystyrene (PS) are obtained by coating the particles with a <2‐nm layer of PS adsorbed from dilute solution, prior to incorporation in the composite. Improved mechanical properties of composites containing coated particles, especially NT, are demonstrated by dynamic mechanical analysis at low frequency and low amplitude. Formation of a partially immobilized region of polymer surrounding the particles is quantified using flow microcalorimetry with ethyl acetate or methyl ethyl ketone vapor to measure the increase in solvation enthalpy in this region. This calorimetric method is applied to both composites and compacted powder mixtures of NT or CB with PS. The response of integral heat of vapor sorption as a function of particle loading in powder mixtures is similar to percolation curves reported for mechanical and electrical properties of composites. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1821–1834, 2006
Hydrogen bonding, mobility, and structural transitions in aliphatic polyamides
Authors: Murthy N. Sanjeeva 
Published: May 2006

AbstractSome salient results in nylon research are reviewed to identify the fundamental principles that are applicable to other strongly interacting or hydrogen‐bonded polymers, including proteins. The effects of hydrogen bonds on stress‐, heat‐, and solvent‐induced changes in macroscopic properties are discussed. These data provide a window into the chain mobility and linkages between the crystalline and amorphous domains, both of which are important for any predictive model. The changes in the characteristics of the amorphous phase with the crystallinity and orientation require that it be modeled with at least two components: a rigid/immobile/anisotropic component and a soft/mobile/isotropic component. The deformation and shrinkage behavior of these polymers are discussed in terms of the relative contributions of the amorphous and crystalline domains and of the interactions between them. The premelting crystalline transition is accompanied by the merging of intersheet and intrasheet diffraction peaks in some nylons, as observed by Brill, and not in others even though the underlying mechanism that gives rise to these transitions, the onset of volume‐increasing librational motion of the crystalline stems, is the same. Because the effects of the temperature, deformation, and solvent have a common origin associated with mobility, a fictive temperature can be associated with a given solvent activity or stress level. The magnitude of this fictive temperature is the amount by which the glass or Brill transition temperature is reduced in the presence of solvents (∼50 °C) or stress or by which the annealing temperature can be reduced in the presence of a solvent (or active stress) to achieve the same structural state as that of a dry (or static) polymer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1763–1782, 2006
A control technique of oxygen contamination by Ga beam irradiation in InN MOMBE growth
Authors: Isamoto K. , Uesaka Y. , Yamamoto A. , Hashimoto A. 
Published: May 2006

AbstractWe have investigated about a control technique of oxygen contamination into the InN layers by simultaneous irradiation of Ga beam during RF‐MOMBE growth using the combination of the TMIn and the RF‐plasma nitrogen sources. Red shifts of the band gap energy and the improvement of the electrical properties have been achieved by the Ga beam irradiation. The suppresssion mechanism of the oxygen contamination has been discussed from the experimental results of the InN growth by the RF‐MOMBE with the Ga beam irradiation. The present results strongly indicate that the simultaneous irradiation of the Ga beam would be useful to suppress the oxygen contamination into the InN layers during the growth. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Towards fabrication of In‐polar InN films and InN/GaN MQWs
Authors: Yamaguchi Wataru , Che Song‐Bek , Kikukawa Naohiro , Ishitani Yoshihiro , Yoshikawa Akihiko 
Published: May 2006

AbstractIn‐polarity InN films were grown by radio frequency plasma‐assisted molecular‐beam epitaxy and their structural properties as a function of III/V beam‐flux ratio were investigated. It was found that the window for the surface stoichiometry to achieve high quality InN films was very narrow; only 11% change in In beam‐equivalent pressure drastically affected surface morphology and structural property. This is because the upper‐limited growth temperature of the In‐polarity growth is as low as about 500 °C. Under the growth condition around the unity stoichiometry, a step‐flow‐like surface with a 2 mono‐layer step height was obtained in the In‐polarity growth. Best values for the measurements of structural and electrical properties were as follows; full width at half maximum of X‐ray rocking curves were 645 arcsec and 1425 arcsec for (0002) and (10‐12) reflections, respectively and the electron concentration and mobility were 1.3×1018 cm–3 and 1650 cm2/V s, respectively. Furthermore, we tried to fabricate In‐polarity InN/GaN multi‐quantum wells with a 1 mono‐layer InN well thickness. A result of X‐ray 2θ–ω scan showed clearly satellite peaks up to 2nd order and fringe peaks, which indicates that a fine periodic structure is achieved in the In‐polarity MQWs. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bowing of thick GaN layers grown by HVPE using ELOG
Authors: Hennig Ch. , Richter E. , Zeimer U. , Weyers M. , Tränkle G. 
Published: May 2006

AbstractIntrinsic stress in GaN layers grown by HVPE on sapphire substrates results in wafer breakage for thicknesses exceeding 40 µm. Using ELOG 180 µm GaN can be grown on 2 inch. The bowing of the wafers caused by extrinsic stress due to the different thermal expansion is not affected by ELOG. Using WSiN as mask material a 600 µm thick free‐standing 2 inch GaN layer has been obtained by exploiting the shear forces occurring during cooling after growth for separation from the ELOG template. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microfabrication of GaN groove on sapphire substrate treated selectively by electron‐beam
Authors: Matsumura H. , Sumiya M. , Kawai Y. , Tomiki M. , Murakami K. , Fuke S. 
Published: May 2006

AbstractH2‐cleaned sapphire substrate was treated with an electron‐beam aiming at polarity‐selective growth of GaN film by using metalorganic chemical vapor deposition (MOCVD). It was found that GaN growth on the sapphire substrate treated with an electron‐beam was suppressed like GaN growth on a SiO2 mask. GaN grooves having the fluctuated sidewalls were fabricated as designed by lithography patterns due to the selective growth. The groove sidewalls became smoother after etching by dipping in a KOH aqueous solution. This improvement was enhanced for the grooves oriented along <11$ \bar 1 $0> direction, compared to those along <1$ \bar 2 $00> direction. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quality and uniformity assessment of AlGaN/GaN quantum wells and HEMT heterostructures grown by molecular beam epitaxy with ammonia source
Authors: Cordier Y. , Pruvost F. , Semond F. , Massies J. , Leroux M. , Lorenzini P. , Chaix C. 
Published: May 2006

AbstractIn the present work, AlGaN/GaN quantum wells and High Electron Mobility Transistors (HEMTs) have been grown by molecular beam epitaxy on Si(111) and GaN on sapphire templates. The optical quality and the electrical properties were studied by low temperature photoluminescence and Hall effect. These measurements attest the quality of these heterostructures and demonstrate the high on‐wafer uniformity of the materials grown on 50 mm wafers, and this even for the III‐nitrides grown on Silicon. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Surface segregation of Si and Mg dopants in MOVPE grown GaN films revealed by X‐ray photoemission spectro‐microscopy
Authors: Schmidt Th. , Siebert M. , Flege J. I. , Gangopadhyay S. , Pretorius A. , Kröger R. , Figge S. , Gregoratti L. , Barinov A. , Hommel D. , Falta J. 
Published: May 2006

AbstractThe surface segregation of Mg and Si dopant species in GaN films has been investigated by means of combined X‐ray photoemission spectroscopy and microscopy. For both species, a segregation tendency was detected. Comparing Mg doped samples before and after Ar ion sputtering, a Mg surface enrichment is concluded on that extends at least over several atomic layers. For Si doped films, the formation of facetted cracks with threefold symmetry was observed. The Si surface concentration was found to be enhanced at the facets of these cracks by a factor of 2.5 with respect to the c ‐plane surface. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of hydrogen implantation induced blistering in GaN
Authors: Singh R. , Radu I. , Gösele U. , Christiansen S. H. 
Published: May 2006

AbstractA systematic investigation of surface blister formation on GaN epitaxial layers implanted with 100 keV H2+ ions with a dose of 1.3×1017 cm–2 and annealed at various temperatures in the range of 350–700 °C was carried out. Two different activation energies were found for the formation of surface blisters: 1.79 eV in the lower temperature regime of 350–400 °C and 0.48 eV in the higher temperature regime of 400–700 °C. The depth and width of the blisters were determined using a stylus profilometer. The hydrogen implantation‐induced damage was assessed using cross‐sectional transmission microscopy revealing a band of defects extending from 230–500 nm from the surface of GaN. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Defect density dependence of luminescence efficiency and lifetimes in AlGaN active regions exhibiting enhanced emission from nanoscale compositional inhomogeneities
Authors: Garrett G. A. , Sampath A.V. , Collins C. J. , Readinger E. D. , Sarney W. L. , Shen H. , Wraback M. , Soukhoveev V. , Usikov A. , Dmitriev V. 
Published: May 2006

AbstractAlGaN epilayers grown by plasma‐assisted molecular beam epitaxy and exhibiting high internal quantum efficiency (up to 30%) are incorporated into double‐heterostructure devices grown on base layers of varying defect density. Growth of these AlGaN active layers, having increased emission from localization of carriers in regions of nanoscale compositional inhomogeneities, is found to benefit from base layers of reduced defect density, including thick AlGaN templates grown by hydride vapor phase epitaxy. Nonlinear radiative processes are observed at high optical excitation for layers grown on lower defect base layers. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication of InN/InGaN multiple quantum well structures by RF‐MBE
Authors: Kurouchi M. , Na H. , Naoi H. , Muto D. , Takado S. , Araki T. , Miyajima T. , Nanishi Y. 
Published: May 2006

AbstractInN/InGaN multiple quantum well structures have been fabricated on InN templates grown on (0 0 0 1) sapphire substrates by radio‐frequency plasma‐assisted molecular beam epitaxy. The structures were confirmed by X‐ray diffraction, and satellite peaks up to the 3rd order were observed. From InN/InGaN multiple quantum well structures with different well widths, photoluminescence (PL) emission from the well layers was observed at 77 K, and the PL peak energy slightly blueshifted with decreasing the well width. This dependence can be explained by combined effects of quantum size effect, quantum confined Stark effect, and band filling effect. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of macro defects in SiC substrate on AlGaN/GaN HEMT DC characteristics
Authors: Sazawa H. , Mitani T. , Bang H. , Hirata K. , Kosaki M. , Furuta K. , Tsuchiya T. , Hikosaka K. , Nakashima S. , Okumura H. 
Published: May 2006

AbstractTo clarify the effect of micropipes in SiC substrates on AlGaN/GaN HEMT performance, we fabricated HEMTs, with precise positioning, on and around hollow core at the end of micropipes in the SiC substrate with an overgrown AlGaN/GaN epitaxial layer and evaluated the DC characteristics of the devices. The devices showed poor pinch‐off characteristic and a large gate leakage current. This deterioration in device performance became insignificant at longer distances from the hollow core, and there were no observed differences at a distance of 40 μm. Raman investigation revealed that free carrier (electron) density markedly increased near the hollow core in the GaN layer. The density of carrier was also found to increase within the active region of the degraded device. Because no such increase was observed in the normally functioning device, we concluded that the micropipe in the SiC substrate introduced free carriers into the overgrown epitaxial layer, which degraded the DC characteristics. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The conductivity of Mg‐doped InN
Authors: Cimalla V. , Niebelschütz M. , Ecke G. , Ambacher O. , Goldhahn R. , Lu H. , Schaff W. J. 
Published: May 2006

AbstractUnintentionally doped and Mg doped InN layers were analyzed by sputter depth profiling in an Auger electron spectroscopy equipment. On both layers a strong n‐type surface accumulation of electrons was observed. However, in contrast to the undoped layers the resistivity profile of Mg doped InN shows a strong discontinuity close to the surface. The depth of this discontinuity strongly depends on the oxygen concentration. The energy shift of the InMNN peak was estimated during the depth profiling in order to obtain information about the position of the Fermi level. In the bulk of the Mg doped InN the InMNN peak shift of about 0.2 eV demonstrates the existence of a compensated layer, while the surface is degenerated n‐type. The surface electron accumulation, which is larger by several orders of magnitude, is superimposing the compensation effect of the Mg doping and the InN layer appears to be n‐type. A strong shift of the Fermi level close to the surface was observed, which might be attributed to the formation of InOx. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)