bluuebunny/crossref_metadata_2025 huggingface dataset:
Cathepsin L inhibitor I blocks mitotic chromosomes decondensation during cleavage cell cycles of sea urchin embryos
Authors: Morin Violeta , Sanchez Andrea , Quiñones Karin , Huidobro Jenaro Garcia , Iribarren Claudio , Bustos Paula , Puchi Marcia , Genevière Anne Marie , Imschenetzky Maria
Published: April 2008

We have previously reported that sperm histones (SpH) degradation after fertilization is catalyzed by a cystein–protease (SpH‐protease). Its inhibition blocks the degradation of SpH in vivo and also aborts sea urchin development at the initial embryonic cell cycles. It remains unknown if this effect is a consequence of the persistence of SpH on zygotic chromatin, or if this protease is involved per‐se in the progression of the embryonic cell cycles. To discriminate among these two options we have inhibited this protease at a time when male chromatin remodeling was completed and the embryos were engaged in the second cell cycle of the cleavage divisions. The role of this enzyme in cell cycle was initially analyzed by immuno‐inhibiting its SpH degrading activity in one of the two blastomeres after the initial cleavage division, while the other blastomere was used as a control. We found that in the blastomere injected with the anti‐SpH‐protease antibodies the cytokinesis was arrested, the chromatin failed to decondense after mitosis and BrdU incorporation into DNA was blocked. Since the N‐terminal sequence and the SpH protease was homologous to the cathepsin L (Cat L) family of proteases, we subsequently investigated if the deleterious effect of the inhibition of this protease is related to its Cat L activity. In this context we analyzed the effect of Cat L inhibitor I (Z–Phe‐Phe–CH2F) on embryonic development. We found that the addition of 100 uM of this inhibitor to the embryos harvested at the time of the initial cleavage division (80 min p.i.) mimics perfectly the effects of the immuno‐inhibition of this enzyme obtained by microinjecting the anti‐SpH–protease antibodies. Taken together these results indicate that the activity of this protease is required for embryonic cell cycle progression. Interestingly, we observed that when this protease was inhibited the chromatin decondensation after mitosis was abolished indicating that the inhibition of this enzyme affects chromosomes decondensation after mitosis. J. Cell. Physiol. 216: 790–795, 2008, © 2008 Wiley‐Liss, Inc.
Single‐breathhold four‐dimensional assessment of left ventricular volumes and function using k‐t BLAST after application of extracellular contrast agent at 3 Tesla
Authors: Hamdan Ashraf , Kelle Sebastian , Schnackenburg Bernhard , Wellnhofer Ernst , Fleck Eckart , Nagel Eike
Published: April 2008

Purpose

To prospectively determine the feasibility and accuracy of a four‐dimensional (4D) k‐space over time broad‐use linear acquisition speed‐up technique (k‐t BLAST) for the evaluation of left ventricular (LV) volumes in comparison to standard multiple‐breathhold cine imaging, using a 3.0 Tesla (3T) MR system.

Materials and Methods

In 23 subjects, short‐axis cine loops completely covering the LV were acquired using conventional turbo gradient echo (GRE) imaging. Immediately after administration of gadobenate dimeglumine, a rapid single‐breathhold k‐t BLAST 4D dataset with the same coverage was acquired and reconstructed to short‐axis views. Quantitative aortic flow measurement for LV stroke volume (LVSV) was used to calibrate both techniques. For GRE and k‐t BLAST cine imaging: LV volumes, ejection fraction (EF), and blood‐to‐myocardium‐contrast (BMC) were determined.

Results

k‐t BLAST and GRE sequences showed a strong correlation for LV volumes and EF (r = 0.97–0.99; P < 0.001). Excellent agreement was also found between the LVSV determined by aortic flow measurements and LVSV assessed using GRE sequence and k‐t BLAST sequence. BMC of GRE was similar to that of k‐t BLAST cine imaging.

Conclusion

The use of the single‐breathhold 4D k‐t BLAST technique for the assessment of LV volume is feasible and accurate in 3T MRI. J. Magn. Reson. Imaging 2008;27:1028–1036. © 2008 Wiley‐Liss, Inc.
Assessment of muscle oxygenation with balanced SSFP: A quantitative signal analysis
Authors: Klarhöfer Markus , Madörin Philipp , Bilecen Deniz , Scheffler Klaus
Published: April 2008

Purpose

To investigate the feasibility of balanced steady‐state free precession (b‐SSFP) for blood oxygenation level–dependent (BOLD) MRI during a short‐term ischemia/reactive hyperemia (RH) experiment on human calf muscles.

Materials and Methods

To investigate contributions to the b‐SSFP signal during an RH experiment, the relaxation times T1, T2, and T were quantified in an interleaved fashion. Data from soleus, gastrocnemius, and tibialis muscle groups of five healthy subjects were evaluated.

Results

During ischemia a decreased b‐SSFP signal amplitude as well as a decrease in T2, T, and the initial intensity I0 was observed. RH provoked an overshoot of T2, T, and the b‐SSFP signal. No paradigm‐related changes in T1 were observed. Comparing the evolution of transverse relaxation times, initial intensity, and b‐SSFP signal amplitude, we concluded that the measured b‐SSFP signal in muscle tissue is not only determined by T2 variations but also significantly influenced by I0 changes. These I0 changes are attributed to spin density variations since inflow effects were suppressed by saturation bands.

Conclusion

b‐SSFP signal changes during a RH paradigm cannot unambiguously be assigned to oxygenation changes. Therefore, care has to be taken with their interpretation. J. Magn. Reson. Imaging 2008;27:1169–1174. © 2008 Wiley‐Liss, Inc.
Determining exercise‐induced blood flow reserve in lower extremities using phase contrast MRI
Authors: Nagaraj Hosakote M. , Pednekar Amol , Corros Cecilia , Gupta Himanshu , Lloyd Steven G.
Published: April 2008

Purpose

To study the changes in limb blood flow during lower extremity exercise using phase contrast (PC) MRI in normal volunteers.

Materials and Methods

Healthy volunteers performed plantar flexion exercise (<1 W) for four minutes. Flow velocity was measured using cardiac‐gated, cine PC‐MRI sequences (fast gradient recalled echo [GRE]; multishot echo planar imaging [EPI]) on a 3T scanner at the level of the superficial femoral artery (SFA): 1) preexercise; 2) immediately postexercise; 3) during three minutes recovery; and 4) postrecovery.

Results

At rest there was a triphasic flow waveform in the SFA. During exercise it changed to a monophasic pattern with an increase in total flow; there were variable changes in vessel size and flow velocity. The waveform regained the triphasic pattern during recovery. The exercise‐induced flow reserve (FR) was 167 ± 90%.

Conclusion

PC‐MRI demonstrates that the resting triphasic flow waveform transforms into a monophasic pattern with submaximal exercise and returns to baseline with recovery. This increase in the regional blood flow allows for measurement of exercise‐induced FR in the SFA. J. Magn. Reson. Imaging 2008;27:1096–1102. © 2008 Wiley‐Liss, Inc.
Comparison of quantitative coronary angiography and first‐pass perfusion magnetic resonance imaging for the detection of an impaired coronary perfusion in nonsevere coronary stenosis
Authors: Barmeyer Achim A. , Stork Alexander , Muellerleile Kai , Schofer Anne K. , Tiburtius Claudia , Koester Ralf , Heitzer Thomas , Adam Gerhard , Meinertz Thomas , Lund Gunnar K.
Published: April 2008

Purpose

To compare quantitative coronary angiography (QCA) and first‐pass perfusion magnetic resonance imaging (FPP‐MRI) in symptomatic patients with nonsevere coronary stenosis to detect a reduced coronary flow velocity reserve (CFVR).

Materials and Methods

In 35 patients, FPP‐MRI and CFVR measurements were performed in 40 coronary arteries with a diameter stenosis (DS) <70% by QCA. From FPP‐MRI a myocardial perfusion reserve index (MPRI) was calculated. CFVR was calculated as the ratio of the average peak flow velocity during infusion of adenosine and at rest and was considered reduced if <2. Diagnostic performance of MPRI and DS to detect a reduced CFVR was compared by receiver operating characteristic (ROC) curve analysis.

Results

CFVR was reduced in 16 coronary arteries (40%). Mean DS did not differ in coronary arteries with a reduced CFVR (41.0% ± 13.3) and a normal CFVR (36.5% ± 12.3; P = 0.281). Mean MPRI was lower in coronary arteries with a reduced CFVR (1.12 ± 0.12) compared to a normal CFVR (1.33 ± 0.2; P < 0.001). Sensitivity, specificity, and area under the ROC curve (AUC) were higher for MPRI (81%, 79%, 0.84) than for DS (56%, 58%, 0.60).

Conclusion

FPP‐MRI detects impaired CFVR in symptomatic patients with nonsevere coronary stenosis more accurately than QCA and can identify patients with symptomatic ischemia. J. Magn. Reson. Imaging 2008;27:1005–1011. © 2008 Wiley‐Liss, Inc.
Interstudy reproducibility of SSFP cine magnetic resonance: Impact of magnetic field strength and parallel imaging
Authors: Maroules Christopher D. , McColl Roderick , Khera Amit , Peshock Ronald M.
Published: April 2008

Purpose

To study the effects of field strength and parallel imaging on image contrast and interstudy reproducibility of right and left ventricular (RV and LV) measurements using steady‐state free precession (SSFP) cardiovascular magnetic resonance (CMR).

Materials and Methods

Thirty‐two subjects (20 normal, 12 cardiac patients) underwent four SSFP cine short‐axis imaging studies: two at 1.5T, one at 3T, and another at 3T with parallel imaging (SENSE). RV and LV contrast‐to‐noise ratios (CNRs) were compared between methods. Interstudy reproducibility of RV and LV measurements were assessed by Bland–Altman analyses.

Results

3T SENSE imaging reduced total imaging time from 8 ± 2 minutes to 3 ± 1 minute (P < 0.001). A significant gain in LV CNR was detected between 1.5T and 3T with SENSE (43.8 ± 6.5 vs. 48.4 ± 7.4, P = 0.01), but no significant gain was detected in RV CNR. The reproducibility of LV and RV measurements between two 1.5T studies was not significantly different from the reproducibility between a 1.5T study and a 3T study with SENSE.

Conclusion

SENSE imaging at 3T is a reproducible technique for assessing RV and LV structure and function. J. Magn. Reson. Imaging 2008;27:1139–1145. © 2008 Wiley‐Liss, Inc.
Assessment of regional myocardial oxygenation changes in the presence of coronary artery stenosis with balanced SSFP imaging at 3.0T: Theory and experimental evaluation in canines
Authors: Dharmakumar Rohan , Arumana Jain Mangalathu , Tang Richard , Harris Kathleen , Zhang Zhouli , Li Debiao
Published: April 2008

Purpose

To examine the dependence of steady‐state free‐precession (SSFP) ‐based myocardial blood‐oxygen‐level‐dependent (BOLD) contrast on field strength using theoretical and experimental models.

Materials and Methods

Numerical simulations using a two‐pool exchange model and a surgically prepared dog model were used to assess the SSFP‐based myocardial BOLD signal changes at 1.5T and 3.0T. Experimental studies were performed in eight canines with pharmacological vasodilation under various levels of left circumflex coronary artery stenosis. Experimentally obtained BOLD signal changes were correlated against microsphere‐based true flow changes.

Results

Theoretical results showed that, at 3.0T, relative to 1.5T, a threefold increase in oxygen sensitivity can be expected. Experimental studies in canines showed near similar results—a 2.5 ± 0.2‐fold increase in BOLD sensitivity at 3.0T relative to 1.5T (P < 0.05). Based on the scatter gram of BOLD data and microsphere data, it was found that the minimum regional flow difference that can be detected with SSFP‐based myocardial BOLD imaging at 1.5T and 3.0T were 2.9 and 1.6, respectively (P < 0.05).

Conclusion

This study demonstrated that SSFP‐based myocardial BOLD sensitivity is substantially greater at 3.0T compared with 1.5T. The findings here suggest that SSFP‐based myocardial BOLD imaging at 3.0T may have the necessary sensitivity to detect the clinically required minimum flow difference of 2.0. J. Magn. Reson. Imaging 2008;27:1037–1045. © 2008 Wiley‐Liss, Inc.
Effect of vascular stenosis on perfusion‐weighted imaging; differences between calculation algorithms
Authors: Matsushima Shigenori , Kubota Takao , Yamada Kei , Akazawa Kentaro , Masunami Terutoshi , Ito Hirotoshi , Ushijima Yo , Owada Kei , Sasajima Hiroyasu , Mineura Katsuyoshi , Nishimura Tsunehiko
Published: April 2008

Purpose

To determine the most suitable postprocessing technique for magnetic resonance (MR) perfusion imaging in patients with vascular stenosis, by comparing the cerebral blood flow (CBF) maps of single photon emission tomography (SPECT) and perfusion MR imaging (MRI).

Materials and Methods

In 15 consecutive patients (14 men and one woman, mean age 73.9 ± 6.0 years) with stenosis of common carotid artery (CCA) or internal carotid artery (ICA) of more than 75%, both brain perfusion MRI and brain perfusion SPECT were performed. From perfusion MR images, CBF maps were calculated with the first moment, singular value decomposition (SVD), and block circulant SVD (b‐SVD) methods, and CBF maps from each algorithm were compared with those from SPECT.

Results

The b‐SVD method had the best correlation with SPECT (R = 0.814), followed by the first moment method (R = 0.776) and the SVD method (R = 0.723). The b‐SVD method has the least mean difference with SPECT (0.118), the first moment method also had less difference (0.121), and the SVD had greatest mean difference (0.164).

Conclusion

Our results suggest that in patients with vascular impairment the b‐SVD method will be the technique of choice rather than SVD or first moment method. J. Magn. Reson. Imaging 2008;27:1103–1108. © 2008 Wiley‐Liss, Inc.
Gadolinium‐based contrast agents and their potential role in the pathogenesis of nephrogenic systemic fibrosis: The role of excess ligand
Authors: Sieber Martin A. , Lengsfeld Philipp , Walter Jakob , Schirmer Heiko , Frenzel Thomas , Siegmund Fred , Weinmann Hanns‐Joachim , Pietsch Hubertus
Published: April 2008

Purpose

To investigate the role of excess ligand present in gadolinium (Gd) ‐based contrast agents in the development of nephrogenic systemic fibrosis (NSF). Using a dosing regimen to simulate the exposure seen in patients with severe renal impairment, we investigated the effect of excess ligand on Gd‐deposition and the depletion of endogenous ions.

Materials and Methods

Gadodiamide and gadoversetamide were formulated with 0%, 5%, and 10% excess ligand. Forty‐two, healthy, male Hannover Wistar rats received daily intravenous injections of each formulation over a period of 20 days. At the end of the study, histopathological analysis of the skin was performed and the concentrations of Gd, Zn, and Cu were measured in several tissues. The levels of Zn in the urine were also measured.

Results

The most severe skin lesions were observed after injection of formulations containing 0% free ligand and in those animals with the highest Gd concentrations in the skin. There were no significant reductions in the levels of Zn or Cu observed in the skin; however, the levels of Zn in the urine were elevated following administration of formulations with the highest amount of excess ligand.

Conclusion

Our findings suggest that there is an inverse correlation between the amount of excess ligand present in Gd‐containing contrast agents and the amount of Gd in the tissue, and further underline the importance of the inherent stability of these agents in the development of NSF. J. Magn. Reson. Imaging 2008;27:955–962. © 2008 Wiley‐Liss, Inc.
Local fuel concentration measurements for mixture formation diagnostics using diffraction by laser‐induced gratings in comparison to spontaneous Raman scattering
Authors: Kiefer J. , Kozlov D. N. , Seeger T. , Leipertz A.
Published: April 2008

The potential of the laser‐induced gratings (LIGs) technique for the determination of fuel concentrations is investigated in comparison to the well‐established spontaneous Raman scattering (SRS) technique. At pulse‐repetitive excitation, the temporal shape of the LIG signals, containing non‐resonant electrostrictive and resonant thermal contributions, as well as the Raman spectra were recorded in single‐shot and accumulation modes. The measurements were performed in a laboratory system: in mixtures of propane as a fuel with nitrogen and air under stationary conditions in order to provide calibration data and to investigate the single‐shot precision of measurements; and in the course of pulsed injection of gaseous propane into air at elevated pressures and temperatures. In the latter case, parameters of the experiment such as temperature, amount of injected gas and pressure were adjusted to be close to conditions of practical interest existing in real engines with direct injection (DI). The temporal variation of local propane concentration was tracked after the start of the injection pulse. Various approaches to the fast evaluation of the temporal shape of the measured LIG signals were tested, and their applicability in different ranges of propane concentrations, as well as single‐shot measurement precision, were investigated. The results of employing the LIG technique were compared to those provided by the evaluation of the ratio of the integrated line intensities in the recorded SRS spectra. Copyright © 2008 John Wiley & Sons, Ltd.
Effects of pressure toasting on in situ degradability and intestinal protein and protein‐free organic matter digestibility of rapeseed
Authors: Azarfar Arash , Ferreira Claudio S , Goelema Jacob O , Van der Poel Antonius FB
Published: April 2008

BACKGROUND: Rapeseed is a protein supplement that contains up to 40% crude protein (CP) on a dry matter (DM) basis, but a large part of its protein can be easily degraded in the rumen. Therefore, before inclusion in ruminant's diet, the extent of its protein degradation in the rumen must be reduced without altering its intestinal digestibility. A study was conducted to investigate the effects of pressure toasting (T, 130 °C) at two residence times (1.5 and 10 min) alone or in combination with soaking in water (ST, 4 h) on ruminal degradability and intestinal digestibility of CP and protein‐free organic matter (PFOM) in whole full‐fat rapeseed.

RESULTS: Regardless of the processing time (1.5 or 10 min), T significantly (P < 0.05) increased the fraction of undegraded intake protein (UIP) compared to the untreated rapeseed samples. Soaking prior to further toasting did not improve the rumen degradation characteristics of rapeseed CP. Compared to the untreated rapeseed samples, both T and ST significantly (P < 0.0001) improved the true protein digested in the small intestine (DVE) and degraded protein balance (OEB), effects that were more evident in samples heated for 10 min. Soaking prior to pressure toasting, however, did not further improve the DVE or OEB in the rapeseed samples in comparison with T treatment.

CONCLUSIONS: It was concluded that ruminal protein degradability of rapeseed decreased after pressure toasting, without seriously affecting its intestinal digestibility. Copyright © 2008 Society of Chemical Industry
Application of surface response methodology to optimize hydrolysis of wheat gluten and characterization of selected hydrolysate fractions
Authors: Drago Silvina R , González Rolando J , Añón María C
Published: April 2008

BACKGROUND: The aim of this work was to optimize the hydrolysis experimental conditions to obtain wheat gluten hydrolysates and to characterize fractions from hydrolysates with different hydrolysis degrees in order to develop protein functional ingredients. Surface response methodology was used to analyze the effect of reaction factors on the degree of hydrolysis to assess the conditions for maximum fungal protease enzyme activity. Hydrolysates having three different trichloroacetic acid indices (TCAI) were prepared. Soluble fractions at pH 4, 6.5 and 9 from these hydrolysates were characterized by electrophoresis, reverse‐phase high‐performance liquid chromatography, free amino group content and peptide chain length.

RESULTS: Temperature and pH ranges for highest enzyme activity at 2.5 h were 54–58 °C and 4.2–4.4, respectively. Hydrolysate fraction composition differs according to the hydrolysis degree and extracting pH, the difference being more pronounced at low TCAI. Hydrolysate having 32% TCAI is composed of peptides whose size is lower than 18.5 kDa, with an average peptide chain length of 14 amino acid residues.

CONCLUSION: The combination of hydrolysis degree and pH of extraction allows fractions of different peptide composition to be obtained, which could be taken into account when trying to find a defined composition related to determined functional characteristics. Copyright © 2008 Society of Chemical Industry
Impact of type of liver resection on the outcome of colorectal liver metastases: A case‐matched analysis
Authors: Guzzetti Eleonora , Pulitanò Carlo , Catena Marco , Arru Marcella , Ratti Francesca , Finazzi Renato , Aldrighetti Luca , Ferla Gianfranco
Published: April 2008

Background

Wedge resection (WR) for colorectal liver metastases (CLM) has become more common in an attempt to preserve liver parenchyma. However, some investigator have reported that WR is associated with a higher incidence of positive margin and an inferior survival compared with anatomic resection (AR) 1.

Objectives

This study evaluated survival, margin status, and pattern of recurrence of patients with CLM treated with WR or AR.

Methods

We identified 208 consecutive patients, in a single institutional database from 1995 to 2004, who underwent either WR or AR. WR was defined as a nonanatomic resection and AR was defined as single resection of one or two liver segments. Patients with combined WR–AR and patients requiring resection of more than two segments or radiofrequency ablation were excluded from the analysis.

Results

One hundred six patients underwent WR and 102 patients had AR. There were no differences in the rate of positive surgical margin (P = 0.146), overall recurrence rates (P = 0.211), and patterns of recurrence between the two groups (P = 0.468). The median survival was 32 months for WR and 42 for AR, with 5‐year survival rates of 29% and 27% respectively, with no significant difference (P = 0.308). Morbidity was similar between the two groups.

Conclusions

WR is a safe procedure and does not disadvantage the patients in terms of tumor recurrence and overall survival. J. Surg. Oncol. 2008;97:503–507. © 2008 Wiley‐Liss, Inc.
A fast elastostatic solver based on fast Fourier transform on multipoles (FFTM)
Authors: He Xuefei , Lim Kian Meng , Lim Siak Piang
Published: April 2008

In this paper, we present a fast algorithm to solve elasticity problems, governed by the Navier equation, using the boundary element method (BEM). This fast algorithm is based on the fast Fourier transform on multipoles (FFTM) method that has been developed for the Laplace equation. The FFTM method uses multipole moments and their kernel functions, together with the fast Fourier transform (FFT), to accelerate the far field computation. The memory requirement of the original FFTM tends to be high, especially when the method is extended to the Navier equation that involves vector quantities. In this paper, we used a compact representation of the translation matrices for the Navier equation based on solid harmonics. This reduces the memory usage significantly, allowing large elasticity problems to be solved efficiently. The improved FFTM is compared with the commonly used FMM, revealing that the FFTM requires shorter computational time but more memory than the FMM to achieve comparable accuracy. Finally, the method is applied to calculate the effective Young's modulus of a material containing numerous voids of various shapes, sizes and orientations. Copyright © 2008 John Wiley & Sons, Ltd.
Strength of short fiber reinforced polymers: Effect of fiber length distribution
Authors: Aykol Muratahan , Isitman Nihat Ali , Firlar Emre , Kaynak Cevdet
Published: April 2008

In this study, the prediction of mechanical strength of short fiber reinforced plastics (SFRPs) is made possible by obtaining a Fiber Length Distribution (FLD) efficiency factor, ηFLD, from the formerly known twofold discrete strengthening equation of Kelly–Tyson. The unified parameter ηFLD is developed involving both the effects of fiber breakage and resulting distribution, fiber volume fraction and fiber and interface properties, so that they can be incorporated into modified rule of mixtures (MROM). This procedure helps to clarify the experimentally observed loss in strengthening rate with increasing fiber fraction. By adapting a few experimentally determined distributions to a Weibull type function, the analytical solutions described in this study establish the exploration of the strength of SFRPs in the entire fiber content range or can reveal the interfacial bond strength. After investigating the effects of fiber and interface parameters on strengthening efficiency, it is found that common fiber‐matrix combinations possessing intermediate critical fiber lengths show a significant decrease in strengthening efficiency with increasing fiber content at low fiber loadings. On the contrary, higher and lower critical fiber lengths yield less significant losses. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Conservative management of emphysematous pyelonephritis in type 1 diabetes
Authors: Mckenna C , Ripley D , Pearson A , Leslie PJ
Published: April 2008

Emphysematous pyelonephritis (EPN) is a rare but life threatening infection of the renal parenchyma, which is strongly associated with diabetes. Here we present a case of class 3B EPN that highlights the characteristic radiological findings as well as the successful use of conservative treatment. Copyright © 2008 John Wiley & Sons.
Prevalence and characteristics of anaemia in diabetes
Authors: Adetunji OR , Mani H , Olujohungbe A , Ronald J , Morgan C , Gill Gv
Published: April 2008

There are an increasing number of patients with diabetes who have been found to be anaemic without underlying evidence of chronic renal disease. The cause of this anaemia is mainly unknown. This study set out to determine the prevalence and characteristics of anaemia in our local diabetes population.

Five hundred and thirty‐one patients attending the diabetes outpatient department were consecutively screened for anaemia with a full blood count after written informed consent was taken. Anaemia was defined by World Health Organization criteria (<13g/dl for men, and <12g/dl for women). The urinary albumin–creatinine ratio, serum creatinine and estimated glomerular filtration rate were determined.

Of the 531 screened, anaemia was present in 134 (25%) patients. Only 26 (19%) of those with anaemia had previously known nephropathy and 16 (12%) had microcytic anaemia. The majority of the anaemic population were previously undetected with no obvious cause for the anaemia.

Anaemia was common in the study population. Screening routinely for anaemia at annual diabetes follow‐up clinics may be a cheap and effective way of identifying patients at risk of impaired quality of life and increased cardiovascular risk. Copyright © 2008 John Wiley & Sons.
Comparative proteomic analysis of mouse livers from embryo to adult reveals an association with progression of hepatocellular carcinoma
Authors: Lee Nikki P. Y. , Leung Kar‐wai , Cheung Nicole , Lam Brian Y. , Xu Michelle Z. , Sham Pak C. , Lau George K. , Poon Ronnie T. P. , Fan Sheung Tat , Luk John M.
Published: April 2008

To identify potential oncofetal biomarkers that distinguish hepatocellular carcinoma (HCC) from healthy liver tissues, we compared and analyzed the proteomic profiles of mouse livers at different developmental stages. Fetal (E13.5, E16.5), newborn (NB), postnatal (3‐week) and adult (3‐month) livers were isolated and profiled by 2‐D PAGE. Statistical analysis using linear regression and false discovery rate (FDR) revealed that 361 protein spots showed significant changes. Unsupervised hierarchical tree analysis segregated the proteins into fetal, NB, and postnatal‐adult clusters. Distinctive protein markers were identified by MALDI‐TOF/MS and the corresponding mRNA profiles were further determined by Q‐PCR. Fetal markers (hPCNA, hHSP7C, hHEM6) and postnatal‐adult markers (hARGI1, hASSY, hBHMT, hFABPL) were selected for testing against a panel of seven human hepatocyte/HCC cell lines and 59 clinical specimens. The fetal proteins were found to be overexpressed in the metastatic HCC cell lines and the tumor tissues, whereas the postnatal‐adult proteins were expressed in non‐tumor tissues and normal hepatocytes. This “Ying‐Yang” pattern, as orchestrated by distinct fetal and adult markers, is hypothesized to indicate the progressive change of the liver from a growing, less‐differentiated organ into a functional metabolic center. Thus, embryogenesis and tumorigenesis share certain oncofetal markers and adult “hepatic” phenotypes are lost in HCC.
Low frequency noise in Co/Al2O3〈Si〉/Py magnetic tunnel junctions
Authors: Guerrero R. , Aliev F. G. , Villar R. , Santos T. , Moodera J.
Published: April 2008

Low frequency noise and dynamic tunneling resistance have been studied in Co(80 Å)/Al2O3(12 Å)/Py(100 Å) magnetic tunnel junctions (MTJs) with and without asymmetric Si doping of the insulating barrier (Si ≤ 1.8 Å). Variation of the dynamic resistance and tunneling resistance with Si doping and applied bias in these MTJs indicate a transition from the Si‐doped regime to Si cluster formation above a δ ‐layer thickness of about 1.2 Å, close to 1 monolayer coverage. The measurements show anomalously strong enhancements of the low frequency noise for Si thickness above 1.2 Å, mainly due to the appearance of random telegraph noise. A simple model, which considers suppression of Coulomb blockade in the array of Si dots, opening two‐step tunnel channels, qualitatively explains the variation of both conductivity and noise with Si content. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
XMCD studies of Cox Pt100–x nanoparticles prepared by vapour deposition and chemical synthesis
Authors: Imperia P. , Glaser L. , Martins M. , Andreazza P. , Penuelas J. , Alessandrovic V. , Weller H. , Andreazza‐Vignolle C. , Wurth W.
Published: April 2008

An almost linear relation between the Pt amount and the orbital to spin moment ratio (μl/μs) has been found in Cox Pt100–x nanoparticles prepared by vapour deposition and possessing a well defined chemically disordered crystallographic structure. X‐ray magnetic circular dichroism (XMCD) measurements done at the L2,3Co edges show that a 4.0 nm, x = 100 Co reference sample has a ratio μl/μs = 0.097, comparable to values found for Co thin layers. An increase of the amount of Pt increases the μl/μs value: μl/μs = 0.11 for x = 78, μl/μs = 0.12 when x = 74 and finally, for x = 38 it becomes μl/μs = 0.140. Nanoparticles prepared by chemical synthesis with size proportional to changes of the stoichiometric ratio, from Co25Pt75 to Co50Pt50, show values of the orbital to spin moment ratio compatible with the trend found for the former ones. The samples prepared by chemical synthesis in a diameter range from 4 nm to 8 nm are characterized by a sharp size distribution of 10%. In contrast to the in situ prepared nanoparticles that are oxide free, however, they show a varying degree of surface oxidation depending on the ambient conditions they are exposed to. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
MBE growth of AlN/GaN‐based photovoltaic intersubband photodetectors
Authors: Monroy E. , Guillot F. , Baumann E. , Giorgetta F. R. , Hofstetter D.
Published: April 2008

We report on the molecular‐beam epitaxial growth, fabrication and characterization of AlN/GaN photovoltaic quantum well infrared photodetectors operating at 1.55 µm. Devices display a spectrally‐narrow photovoltaic response to p‐polarized light in the near infrared at room temperature. We have analysed the effect of the growth temperature, quantum well thickness, and number of periods in the active region, concluding that responsivity is enhanced by growing at relatively low temperature and by increasing the number of quantum wells. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Low noise characteristics of AlGaInN‐based self‐pulsating laser diodes
Authors: Obata T. , Kitajima N. , Ohta M. , Ichinokura H. , Kuramoto M.
Published: April 2008

We have successfully realized practical self‐pulsating laser diodes (SP‐LDs) based on AlGaInN systems that exhibit low noise characteristics even with an optical feedback of 1% at a high temperature of 75 °C. Our fabricated SP‐LD employs a saturable absorber layer (SAL). We adopt new approaches to realize practical SP operation; specifically, (i) we inserted an AlGaN layer between the active layer and the SAL in order to reduce the threshold current, and (ii) we intentionally introduced reactive ion etching (RIE) damage to the SAL in order to reduce the carrier lifetime in the SAL by controlling the distance between the SAL and the dry‐etched surface. The threshold currents for the fabricated SP‐LD at 25 °C and 75 °C were 38.8 mA and 54.4 mA, respectively. We also demonstrated that it is possible to suppress the relative intensity noise (RIN < –125 dB/Hz) even under the conditions of high temperature (75 °C) and an optical feedback of 1%. These results indicate that practical SP‐LDs for use in optical storage devices can be realized by inducing dry etching damage in the SAL. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantum dots excited InGaN/GaN phosphor‐free white LEDs
Authors: Chua S. J. , Soh C. B. , Liu W. , Teng J. H. , Ang S. S. , Teo S. L.
Published: April 2008

Commercial GaN based white LEDs have been fabricated using phosphor coating of blue LEDs. We report on the growth of InGaN/GaN based white LEDs using In‐rich InGaN quantum dots incorporated in the MQW layers. The photoluminescence spectrum of the MQWs shows a broad emission spectrum covering 400 to 700 nm. Cross‐section TEM shows the existence of pyramidal shaped quantum‐like structures with size of 1.5‐2.0 nm embedded in the InGaN well. To prevent the out‐diffusion of these InGaN quantum dots in the well layer during thermal activation of p‐GaN, a small amount of Indium was introduced into the p‐GaN and the temperature was kept below 800 °C for p‐InGaN epilayer growth. I‐V measurement of the white LEDs gives a forward voltage of 5.2 V for a current of IF ∼20mA. The chromaticity coordinate ranges from 0.28 < x,y < 0.34 with a colour temperature of ∼6000 K. The internal quantum efficiency was separately determined to be in excess of 50%. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Properties of ZnO(0001) layers grown by metalorganic chemical vapor deposition on GaN(0001) templates
Authors: Ive T. , Ben‐Yaacov T. , Asamizu H. , Van de Walle C. G. , Mishra U. , DenBaars S. P. , Speck J. S.
Published: April 2008

We studied the properties of ZnO(0001) layers grown by metalorganic chemical vapor deposition on GaN(0001) templates. A two‐step growth procedure was used where a buffer layer was first deposited at 400 °C before the temperature was increased to 900 °C for the deposition of the epitaxial layer. Atomic force microscopy revealed locally straight steps on a 20 × 20 mm2 scan area. This indicates a step‐flow growth mode. The root‐mean‐square roughness was 2.6 nm. The surface exhibited hexagonal pits. The pit density was 7.5 × 105–2.1 × 108 cm–2. The full width at half maximums of w‐scans for the symmetric (0002) and the skew‐symmetric (20$ \bar 2 $1) reflections were 0.091° and 0.159°, respectively. The ZnO films were fully relaxed as revealed by reciprocal space maps for the (10$ \bar 1 $5) reflection. Gallium doped n‐type ZnO layers were deposited on (In,Ga)N light emitting diodes as transparent contacts. The electron concentration was 9.4 × 1019 cm–3 and the sheet resistance 45 W/sq. The resistivity and the mobility was 1.5 × 10–3 Wcm and 43 cm2/(Vs), respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of deep level incorporation in ammonia and rf‐plasma assisted molecular beam epitaxy n‐GaN films
Authors: Arehart A. R. , Corrion A. , Poblenz C. , Speck J. S. , Mishra U. K. , DenBaars S. P. , Ringel S. A.
Published: April 2008

The use of rf‐plasma and ammonia nitrogen sources for growth of GaN films by molecular beam epitaxy (MBE) are compared in terms of defect incorporation using deep level optical spectroscopy (DLOS) and deep level transient spectroscopy (DLTS). To better improve the understanding of ammonia‐based MBE growth of GaN and potential defect sources as opposed to the more studied plasma source‐based MBE‐grown material several V/III ratios were also investigated, which were generated via systematic adjustment of the ammonia flow rates during growth. The DLOS spectra, comparing deep traps within the n‐GaN grown using N‐plasma and ammonia sources, reveal the presence of the same deep levels due to background carbon and gallium vacancies, with energy levels at EC‐3.28, EC‐2.62, and EC‐1.28. The DLTS results of the N‐plasma and ammonia‐based MBE samples show two similarly dominant electron traps at EC‐0.60, and EC‐0.24 in each sample. Measurements made as a function of V/III flux ratio for ammonia‐based MBE growth indicate a large dependence of the EC‐0.24 eV trap concentration on growth flux ratio, which is significant for guiding continued optimization of this promising MBE growth method for GaN devices. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamics of the mean Asian summer monsoon in a maximally simplified model
Authors: Mak Mankin
Published: April 2008

A two‐layer quasi‐geostrophic model, containing the bare essential orographic and thermal forcings, is used as a maximally simplified model for delineating the nature of the mean Asian summer monsoon circulation (ASM). The solution reveals that the prototype ASM circulation consists of two main components. The western part of it is a greatly elongated and skewed baroclinic vortical circulation. The lower and upper features of the baroclinic vortex are the model counterparts of the Monsoon Low and the Tibetan High respectively. The eastern part of the model ASM is a composite baroclinic Rossby wave‐packet which manifests itself at the lower and upper levels as the model counterparts of the surface Subtropical High and upper‐level Monsoon Trough. The centre of the skewed vortex and the root of the wave‐packet are collocated over East Asia arising from a common source of excitation. This overall circulation is interpreted in terms of potential vorticity dynamics. Furthermore, the ascending motion field is consistent with the notion that the thermal forcing is largely self‐reinforcing. The descending motion over the model Middle East supports the notion that the desert climate is an integral part of the ASM. The roles of the individual model forcing elements are also delineated and the caveats of the analysis elaborated. Copyright © 2008 Royal Meteorological Society
Circumglobal teleconnections and wave packets associated with Israeli winter precipitation
Authors: Feldstein Steven B. , Dayan Uri
Published: April 2008

This investigation performs diagnostic analyses with NCEP/NCAR reanalysis data and Israeli precipitation data to examine the dynamical processes that drive the teleconnection pattern associated with Israeli winter precipitation anomalies.

A dipole teleconnection pattern with one centre of action over western Europe and another centre of action over the eastern Mediterranean (EM) is found to be associated with the winter precipitation anomalies in Israel. This pattern is referred to as the southern Levant (SL) pattern. The positive (negative) phase of the SL pattern is found to be closely associated with enhanced (reduced) precipitation in Israel. Composites of the 300 hPa stream‐function field show that both phases of the SL pattern are associated with eastward propagating wave packets that traverse about three‐quarters of the distance across the globe. These wave packets, which have a phase speed that is close to zero, originate over the northeast Pacific (the east coast of North America) for the positive (negative) SL phase, and propagate eastward across the North Atlantic, western Europe, the EM, and southern Asia, until they eventually decay over the northwest Pacific. As these wave packets pass over western Europe and the EM, the SL pattern is triggered and anomalies in Israeli winter precipitation occur.

The SL pattern is found to have an e‐folding time‐scale of 4 days, which is determined by the group velocity of the wave packet. The time‐averaged spatial structure of the circumglobal wave packet closely resembles the first empirical orthogonal function of the hemispheric 300 hPa meridional wind field. This suggests that the circumglobal wave packet may be a fundamental pattern of variability which is relevant for the entire Northern Hemisphere. Copyright © 2008 Royal Meteorological Society
Noise due to the Monte Carlo independent‐column approximation: short‐term and long‐term impacts in ECHAM5
Authors: Räisänen P. , Järvenoja S. , Järvinen H.
Published: April 2008

The Monte Carlo independent‐column approximation (McICA), as a method for computing domain‐average radiative fluxes, allows a flexible treatment of unresolved cloud structure, and is unbiased with respect to the full independent‐column approximation, but its flux estimates contain conditional random noise. In our previous study with the ECHAM5 atmospheric general‐circulation model with prescribed sea‐surface temperatures (SSTs), McICA noise caused a slight reduction in low‐cloud fraction. Here, we first demonstrate that this feature originates from an immediate, nonlinear response of precipitation formation to McICA's random errors in radiative‐heating rates, and is subsequently amplified by a radiative feedback. We then study the long‐term impacts of McICA noise on climate in ECHAM5 simulations employing a mixed‐layer ocean model. The use of interactive rather than prescribed SST somewhat amplifies the reduction in low‐cloud fraction, which contributes to an overall warming of simulated climate with increasing McICA noise. For a typical implementation of McICA, the global‐mean 2 m air temperature is 0.33 K higher than for a low‐noise reference simulation. A 0.1 µm systematic increase in cloud‐droplet effective radius re causes a similar global‐mean warming (0.31 K), with generally similar spatial patterns. However, in the eastern tropical Pacific, McICA noise has locally larger effects than the uniform perturbation in re. It is concluded that the climatic impacts of McICA noise mainly represent a straightforward response to the systematic perturbation in the surface and top‐of‐atmosphere energy budget related to the initial reduction in low cloudiness. Copyright © 2008 Royal Meteorological Society
Effect of surface modification of montmorillonite on the properties of aromatic polyamide/clay nanocomposites
Authors: Zulfiqar Sonia , Ishaq Muhammad , Sarwar Muhammad Ilyas
Published: April 2008

The surface modification of montmorillonite clay was carried out through ion‐ exchange reaction using p‐phenylenediamine as a modifier. This modified clay was employed to prepare aromatic polyamide/organoclay nanocomposite materials. The dispersion behavior of clay was examined in the polyamide matrix. Polyamide chains were synthesized from 4‐aminophenyl sulfone and isophthaloyl chloride (IPC) in dimethylacetamide. These amide chains were suitably end‐capped with carbonyl chloride end groups to interact chemically with modified montmorillonite clay. The resulting nanocomposite films containing 2–20 wt% of organoclay were characterized by TEM, X‐ray diffraction (XRD), thin‐film tensile testing; thermogravimetric analysis (TGA), differential scanning calorimetric (DSC) and water absorption measurements. Mechanical testing revealed that modulus and strength improved up to 6 wt% organoclay loading while elongation and toughness of nanocomposites decreased with the addition of clay content in the matrix. Thermal decomposition temperatures of the nanocomposites were in the range 225–450 °C. These nanocomposites expressed increase in the glass‐transition temperature values relative to pure polyamide describing interfacial interactions among the phases. The percent water uptake of these composites reduced upon the addition of modified layered silicate depicting improved barrier properties. Copyright © 2008 John Wiley & Sons, Ltd.
Serum prolactin as a tool for the follow‐up of treated DHPR‐deficient patients
Authors: Concolino D. , Muzzi G. , Rapsomaniki M. , Moricca M. T. , Pascale M. G. , Strisciuglio P.
Published: April 2008

Deficiency of dihydropteridine reductase causes a variant form of phenylketonuria associated with a devastating neurological disease characterized by mental retardation, hypokinesis and other features relating to basal ganglia disorder. Hyperphenylalaninaemias with tetrahydrobiopterin deficiency make up about 1–3% of all hyperphenylalaninaemias. We describe three patients from Calabria, a southern region of Italy, who have a dihydropteridine reductase deficiency, caused by the same mutation (p.L14P) also found in the nearby region of Sicily. We report the evolution of clinical and biochemical data during the treatment of these patients where we used prolactin serum determination to adapt the specific therapy. This report suggests that serum prolactin levels can be a good biomarker for optimal dosage of hydroxylated precursors in long‐term treatment monitoring.
Identity‐in‐context is not yet identity development‐in‐context
Authors: Bosma Harke A. , Kunnen E. Saskia
Published: April 2008

In this discussion, we summarize the main aspects of the research presented in the papers and discuss what we see as their strong points. To analyze recent developments in identity research, we compared the present issue with the special issue of the Journal of Adolescence in 1996 on ‘Identity Development in Context’. In that issue it was concluded that further research is necessary to “detail the ways in which contextual variables may interact both with one another as well as with individual personality variables to determine the course of the identity formation process”.

In the papers in this issue, the influence of the context has received much more attention than 20 years ago. However, they still have serious limitations with regard to the study of the developmental process. Not more than one study uses a longitudinal design. To stimulate research into developmental processes we conclude with a plea for longitudinal studies over long periods, with enough measurement points to distinguish between different patterns, and for more conceptual attention for what identity development is about.