bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fermi surface properties of YbCu2Si2
Authors: Matsuda Tatsuma D. , Dung Nguyen Duc , Haga Yoshinori , Ikeda Shugo , Yamamoto Etsuji , Ishikura Tatsuro , Endo Toyoaki , Takeuchi Tetsuya , Settai Rikio , Ōnuki Yoshichika 
Published: February 2010

AbstractWe succeeded in growing high‐quality single crystals of a heavy electron compound YbCu2Si2. The electronic specific heat coefficient γ is determined to be 150 mJ/K2·mol, which is consistent with the A value of the electrical resistivity from Kadowaki–Woods relation. We succeeded in observing the de Haas‐van Alphen (dHvA) oscillations. The dHvA frequencies and large cyclotron effective masses in YbCu2Si2 are highly different from those in a non‐4f reference compound YCu2Si2. From these dHvA results, the heavy electron state of YbCu2Si2 is characterized by the large contribution of 4f‐electrons to the topology of the Fermi surface and also to the strong enhancement of effective mass caused by the spin fluctuations.
Where is the quantum critical point in the cuprate superconductors?
Authors: Sachdev Subir 
Published: February 2010

AbstractTransport measurements in the hole‐doped cuprates show a “strange metal” normal state with an electrical resistance which varies linearly with temperature. This strange metal phase is often identified with the quantum critical region of a zero temperature quantum critical point (QCP) at hole density $x = x_{\rm m} $, near optimal doping. A long‐standing problem with this picture is that low temperature experiments within the superconducting phase have not shown convincing signatures of such an optimal doping QCP (except in some cuprates with small superconducting critical temperatures). I review theoretical work which proposes a simple resolution of this enigma. The crossovers in the normal state are argued to be controlled by a QCP at xm linked to the onset of spin density wave (SDW) order in a “large” Fermi surface metal, leading to small Fermi pockets for $x > x_{\rm m} $. A key effect is that the onset of superconductivity at low temperatures disrupts the simplest canonical quantum critical crossover phase diagram. In particular, the competition between superconductivity and SDW order shifts the actual QCP to a lower doping $x_{\rm s} > x_{\rm m} $ in the underdoped regime, so that SDW order is only present for $x > x_{\rm s} $. I review the phase transitions and crossovers associated with the QCPs at xm and xs: the resulting phase diagram as a function of x, temperature, and applied magnetic field consistently explains a number of recent experiments.
Flux crystal growth of CeCu2Si2: Revealing the effect of composition
Authors: Seiro S. , Deppe M. , Jeevan H. , Burkhardt U. , Geibel C. 
Published: February 2010

AbstractThe low‐temperature properties of CeCu2Si2 are extremely sensitive to deviations from stoichiometry and defects, leading to a strong dependence of the observed properties on sample preparation conditions. In the past few years we have developed a flux method which allows the growth of large single crystals with controlled physical properties. Here, we demonstrate that the Ce content in the starting melt, one of the most important parameters in our growth process, mainly influences the Cu/Si ratio in the single crystals but not their Ce content. A higher Cu/Si ratio yields a smaller c/a ratio, while the unit cell volume remains roughly constant. We observe a clear correlation between the Cu/Si ratio and the physical properties, showing that electronic effects are more important than volume effects.
Luttinger liquid physics in the spin ladder material CuBr4(C5H12N)2
Authors: Klanjšek M. , Mayaffre H. , Berthier C. , Horvatić M. , Chiari B. , Piovesana O. , Bouillot P. , Kollath C. , Orignac E. , Citro R. , Giamarchi T. 
Published: February 2010

AbstractWe present a 14N nuclear magnetic resonance study of a single crystal of CuBr4(C5H12N)2 consisting of weakly coupled spin‐1/2 Heisenberg antiferromagnetic ladders. When placed in a magnetic field, such a ladder is theoretically predicted to exhibit a quantum critical Luttinger liquid (LL) behaviour in the gapless phase, i.e. between the two critical fields. Treating ladders as LLs and interaction between them as a perturbation, we are indeed able to fully account for (i) the spin dynamics accessed by measuring the spin–lattice relaxation rate $T_1^{ - 1}$, and for (ii) the phase transition to a 3D ordered phase occurring below 110 mK due to the weak interladder coupling.
Low‐temperature magnetization of the quantum critical heavy fermion superconductor β‐YbAlB4
Authors: Matsumoto Yosuke , Kuga Kentaro , Karaki Yoshitomo , Tomita Takahiro , Nakatsuji Satoru 
Published: February 2010

Abstractβ‐YbAlB4 is the first Yb‐based heavy fermion superconductor with Tc = 80 mK. We measured low‐temperature magnetization of high‐purity single crystals down to T = 25 mK. The measurements have revealed a considerable amount of volume fractions of the superconductivity and the upper critical field Bc2 curve under field along the c‐axis, consistent with the previous results. In the normal state, the previously observed divergent behavior in the temperature dependence of the magnetization has been confirmed using higher‐quality samples and under a low field of 22 mT. In addition, the measurements have revealed a power law behavior, namely, ${\rm d}M/{\rm d}T \propto T^{ - 3/2}$, which has a slightly higher exponent than the previous results.
Nuclear contribution to the specific heat of Yb(Rh0.93Co0.07)2Si2
Authors: Steppke Alexander , Brando Manuel , Oeschler Niels , Krellner Cornelius , Geibel Christoph , Steglich Frank 
Published: February 2010

AbstractSpecific heat measurements of a Yb(Rh0.93Co0.07)2Si2 high‐quality single crystal in magnetic fields $0.5 \leq \mu _0 H \leq 10$ T and in the temperature range between 0.05 and 4 K are presented. To extract the electronic specific heat Cel from the raw data, and consequently the temperature dependence of the Sommerfeld coefficient $\gamma = {{C_{{\rm el}} } \mathord{\left/ {\vphantom {{C_{{\rm el}} } T}} \right. \kern-\nulldelimiterspace} T}$, the nuclear magnetic and electric contributions to the specific heat have been evaluated. The error between the experimental data below 1 K and the theoretical calculation varies between 0.9 and 8.7%, indicating that the coefficients used in our model are accurate and appropriate. The high‐field ground state is confirmed to be a Fermi liquid. This analysis allows to determine the H‐dependence of γ for fields larger than 0.5 T and its change across the anomaly at $\mu _0 H_0 \approx 5.8$ T.
Lack of magnetic ordering in Ce1−xLaxNi2Ge2
Authors: Pikul A. P. , Geibel C. , Oeschler N. , Macovei M. E. , Caroca‐Canales N. , Steglich F. 
Published: February 2010

AbstractThe solid solutions Ce1−xLaxNi2Ge2 ($0 \leq x \leq 1$) were studied by means of physical properties measurements carried out on polycrystalline specimens. The Kondo temperature of the system, estimated from temperature dependence of the magnetic entropy, decreases with increasing the unit cell volume, as expected. Nevertheless the system does not become magnetically ordered. Instead, the non‐magnetic Fermi‐liquid (FL) regime gets evident before other, single‐ion non‐FL features emerge in the low Ce‐content limit.
Field‐induced quantum critical point in the pressure‐induced superconductor CeRhIn5
Authors: Park T. , Tokiwa Y. , Ronning F. , Lee H. , Bauer E. D. , Movshovich R. , Thompson J. D. 
Published: February 2010

AbstractWhen subjected to pressure, the prototypical heavy‐fermion antiferromagnet CeRhIn5 becomes superconducting, forming a broad dome of superconductivity (SC) centred around 2.35 GPa (=P2) with maximal Tc of 2.3 K. Above the superconducting dome, the normal state shows strange metallic behaviours, including a divergence in the specific heat and a sub‐T‐linear electrical resistivity. The discovery of a field‐induced magnetic phase that coexists with SC for a range of pressures P ≤ P2 has been interpreted as evidence for a quantum phase transition, which could explain the non‐Fermi‐liquid behaviour observed in the normal state. Here we report electrical resistivity measurements of CeRhIn5 under magnetic field at P2, where the resistivity is sub‐T‐linear for temperatures above Tc (or TFL) and a T2‐coefficient A found below TFL diverges as Hc2 is approached. These results are similar to the field‐induced quantum critical compound CeCoIn5 and confirm the presence of a quantum critical point in the pressure‐induced superconductor CeRhIn5. Temperature‐field phase diagram of CeRhIn5 at 2.35 GPa.magnified image
The impact of period effects on dose level contrasts in alternating cross‐over designs for first‐time‐in‐human studies
Authors: Koehne‐Voss Stephan , Schmidli Heinz , Smith David M. , Pigeot Iris 
Published: February 2010

AbstractFor first‐time‐in‐human studies with small molecules alternating cross‐over designs are often employed and at study end are analyzed using linear models. We discuss the impact of including a period effect in the model on the precision with which dose level contrasts can be estimated and quantify the bias of least squares estimators if a period effect is inherent in the data that is not accounted for in the model. We also propose two alternative designs that allow a more precise estimation of dose level contrasts compared with the standard design when period effects are included in the model. Copyright © 2010 John Wiley & Sons, Ltd.
Adapting by calibration the sample size of a phase III trial on the basis of phase II data
Authors: De Martini Daniele 
Published: February 2010

AbstractThe problem of estimating the sample size for a phase III trial on the basis of existing phase II data is considered, where data from phase II cannot be combined with those of the new phase III trial. Focus is on the test for comparing the means of two independent samples. A launching criterion is adopted in order to evaluate the relevance of phase II results: phase III is run if the effect size estimate is higher than a threshold of clinical importance. The variability in sample size estimation is taken into consideration. Then, the frequentist conservative strategies with a fixed amount of conservativeness and Bayesian strategies are compared. A new conservative strategy is introduced and is based on the calibration of the optimal amount of conservativeness – calibrated optimal strategy (COS). To evaluate the results we compute the Overall Power (OP) of the different strategies, as well as the mean and the MSE of sample size estimators. Bayesian strategies have poor characteristics since they show a very high mean and/or MSE of sample size estimators. COS clearly performs better than the other conservative strategies. Indeed, the OP of COS is, on average, the closest to the desired level; it is also the highest. COS sample size is also the closest to the ideal phase III sample size MI, showing averages and MSEs lower than those of the other strategies. Costs and experimental times are therefore considerably reduced and standardized. However, if the ideal sample size MI is to be estimated the phase II sample size n should be around the ideal phase III sample size, i.e. n⩾2MI/3. Copyright © 2010 John Wiley & Sons, Ltd.
Comprehensive mass spectrometry based metabolic profiling of blood plasma reveals potent discriminatory classifiers of pancreatic cancer
Authors: Urayama Shiro , Zou Wei , Brooks Kindra , Tolstikov Vladimir 
Published: February 2010

AbstractPoor outcome of pancreatic cancer necessitates development of an early diagnostic method to reduce mortality. No reliable early diagnostic test for pancreatic cancer detection has been developed and validated to date. In the current study, metabolic profiling of plasma samples from selected cancer patients and noncancerous controls was performed to seek novel metabolic biomarkers of pancreatic cancer. A comprehensive mass spectrometry based analytical platform established at the Metabolomics Core of the UC Davis Genome Center allowed detection of multiple compounds previously unreported in plasma from pancreatic cancer patients. It was found that selective amino acids, bile acids, and polar lipids were detected with increased or decreased levels in pancreatic cancer samples compared to controls. These findings on blood plasma levels of the relevant metabolites might be very useful clinical parameters for early diagnosis of pancreatic cancer. Copyright © 2010 John Wiley & Sons, Ltd.
Optimization of N‐methyl‐N‐[tert‐butyldimethylsilyl]trifluoroacetamide as a derivatization agent for determining isotopic enrichment of glycerol in very‐low density lipoproteins
Authors: Adiels Martin , Larsson Thomas , Sutton Pauline , Taskinen Marja‐Riitta , Borén Jan , Fielding Barbara A. 
Published: February 2010

AbstractStable isotope kinetic studies play an important role in the study of very‐low density lipoprotein (VLDL) metabolism, including basic and clinical research. Today, [1,1,2,3,3‐2H5]glycerol is the most cost‐effective alternative to measure glycerol and triglyceride kinetics. Recycling of glycerol from glycolysis and gluconeogenesis may lead to incompletely labelled tracer molecules. Many existing methods for the measurement of glycerol isotopic enrichment involve the production of glycerol derivatives that result in fragmentation of the glycerol molecule after ionization. It would be favourable to measure the intact tracer molecule since incompletely labelled tracer molecules may be measured as fully labelled. The number of methods available to measure the intact tracer in biological samples is limited. The aim of this project was to develop a gas chromatography/mass spectrometry (GC/MS) method for glycerol enrichment that measures the intact glycerol backbone and is suitable for electron ionization (EI), which is widely available. A previously published method for N‐methyl‐N‐[tert‐butyldimethylsilyl]trifluoroacetamide (MTBSTFA) derivatization was significantly improved; we produced a stable derivative and increased recovery 27‐fold in standards. We used the optimized MTBSTFA method in VLDL‐triglyceride and found that further modification was required to take matrix effects into account. We now have a robust method to measure glycerol isotopic enrichment by GC/EI‐MS that can be used to rule out the known problem of tracer recycling in studies of VLDL kinetics. Copyright © 2010 John Wiley & Sons, Ltd.
Transfer of Quantum Dots from Pregnant Mice to Pups Across the Placental Barrier
Authors: Chu Maoquan , Wu Qiang , Yang Hui , Yuan Ruiqi , Hou Shengke , Yang Yifeng , Zou Yajuan , Xu Shi , Xu Kaiyi , Ji Ailing , Sheng Lingyi 
Published: February 2010

AbstractFluorescent quantum dots (QDs) have great potential for in vivo biomedical imaging and diagnostic applications. However, these nanoparticles are composed of heavy metals and are very small in diameter, and their possible toxicity must therefore be considered. As yet, no studies have reported the transfer of QDs between mother and fetus. The transfer of CdTe/CdS QDs of different sizes and dosages, and with different outer capping materials, from pregnant mice to fetuses is investigated. It is shown that QDs may be transferred from female mice to their fetuses across the placental barrier. Smaller QDs are more easily transferred than larger QDs and the number of QDs transferred increases with increasing dosage. Capping with an inorganic silica shell or organic polyethylene glycol reduces QD transfer but does not eliminate it. These results suggest that the clinical utility of QDs could be limited in pregnant women.
Marine huge molecules: the longest carbon chains in natural products
Authors: Kita Masaki , Uemura Daisuke 
Published: February 2010

AbstractMarine huge polyol and polyether compounds are remarkable molecules owing to their extraordinary structures and significant biological activities. Currently, palytoxin and maitotoxin are believed to have the longest carbon chains in nature (more than 100 Å in length), except for biopolymers. The structural properties of such marine huge molecules are highlighted, especially with regard to the length and shape of their carbon chains. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 10: 000–000; 2010: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.200900030
The Impact of Intraoperative Neuromonitoring (IONM) on Surgical Strategy in Bilateral Thyroid Diseases: Is it Worth the Effort?
Authors: Goretzki Peter E. , Schwarz Katharina , Brinkmann Jürgen , Wirowski Denis , Lammers Bernhard J. 
Published: February 2010

AbstractBackgroundIntraoperative nerve monitoring (IONM) of the recurrent laryngeal nerve and the vagal nerve can detect nonfunctioning nerves (recurrent laryngeal nerve palsy, RLNP) that are visibly intact. The use of IONM is questionable, however, as we still lack evidence that it reduces the rate of postoperative nerve injuries. Since negative IONM results after thyroid dissection of the first side could change our surgical strategy and thus could prevent patients from bilateral RLNP, we questioned whether IONM results are reliable enough to base changes in surgical strategy and whether this has any effect on surgical outcome.MethodsWe retrospectively analyzed the data of 1333 consecutive patients with suggested benign bilateral thyroid disease who had been operated on under a defined protocol, including the use of a specific IONM technique (tube electrodes and stimulation of the vagal nerve and the inferior recurrent nerve before and after thyroid resection), between January 1, 2006 and December 31, 2008.ResultsIn four patients the IONM system did not work, two nerves had not been found, and in eight patients the tube had to be readjusted. Of five permanent nerve injuries, four were visible during surgery and one was suspected. Sensitivity of IONM in detecting temporary nerve injuries of macroscopically normal‐appearing nerves was 93%. Specificity was 75–83% at first side of dissection and 55–67% at the second side, with an overall specificity of 77%. In 11 of 13 patients (85%) with known nerve injury (preexisting or visible) and in 20 of 36 patients (56%) with negative IONM stimulation at the first side of dissection, the surgical strategy was changed (specific surgeon or restricted resection) with no postoperative bilateral RLNP. This was in contrast to 3 of 18 (17%) bilateral RLNP (p < 0.05), when surgeons were not aware of a preexisting or highly likely nerve injury at the first side of thyroid dissection.ConclusionsFailed IONM stimulation of the vagal or recurrent laryngeal nerve after resection of the first thyroid lobe is specific enough to reconsider the surgical strategy in patients with bilateral thyroid disease to surely prevent bilateral RLNP.
Changes in Quality of Life After Lung Surgery in Old and Young Patients: Are They Similar?
Authors: Möller Axel , Sartipy Ulrik 
Published: February 2010

AbstractBackgroundThe aim of the study was to compare the changes in health‐related quality of life (QOL) after lung surgery between young and old patients.MethodsWe performed a prospective, population‐based, cohort study to investigate health‐related QOL before and 6 months after lung surgery. We used the validated instrument Short Form‐36 (SF‐36), to investigate QOL. The main outcome measures were fractional change in the SF‐36 physical (ΔPCS%) and mental (ΔMCS%) component summary scores. We also compared the two age groups to age‐ and sex‐matched reference populations.ResultsWe included 249 patients: 166 young (<70 years) and 83 old (≥70 years) patients. The overall response rate at 6 months was 84%. There was no significant difference in the primary outcome measures between young and old patients (ΔPCS% −13 vs. −16, p = 0.55; ΔMCS% 9 vs. 1, p = 0.22). The 2‐year survivals (mean follow‐up 2.1 years) were 83% and 84% in young and old patients, respectively (p = 0.72). In both groups, physical and mental QOL were lower than in the reference populations.ConclusionsWe found that at 6 months after lung surgery old patients experienced deterioration in physical and mental health‐related QOL similar to that of young patients. Survival also was similar in the two groups.
Risk Factors for Symptomatic Anastomotic Leakage After Low Anterior Resection for Rectal Cancer with 30 Gy/10 f/2 w Preoperative Radiotherapy
Authors: Wang Lin , Gu Jin 
Published: February 2010

AbstractObjectiveThis retrospective study was designed to analyze the risk factors for symptomatic leakage after low anterior resection (LAR) for patients with rectal cancer who received 30 Gy/10 f/2 w preoperative radiotherapy.MethodsFrom April 2002 to December 2008, a total of 223 patients with mid‐low rectal cancer received 30 Gy/10 f/2 w preoperative radiotherapy and underwent LAR. Six patients were excluded for positive air test, incomplete anastomotic rings, or other major adverse intraoperative events. In the 217 patients with satisfactory anastomoses, 15 probably factors relating to anastomotic leakage were recorded and statistically analyzed.ResultsThe median patient age was 57 years, and 48% were women. The median level of anastomosis was 6 cm, median operating time was 130 minutes, and intraoperative blood loss was 200 ml. The symptomatic leakage rate was 11.5% (25/217). Multivariable analysis demonstrated that male gender (odds ratio (OR) = 2.63; p = 0.0474), level of anastomosis ≤4 cm (OR = 8.80; p = 0.038), no defunctioning stoma (OR = 3.80; p = 0.038), and blood loss >200 ml (OR = 3.32; p = 0.080) were the independent risk factors for anastomotic leakage.ConclusionsFor patients with rectal cancer treated with preoperative radiotherapy and low anterior resection, the risk factors for anastomotic leakage are male gender, lack of defunctioning stoma, level of anastomosis ≤4 cm, and blood loss >200 ml. A defunctioning stoma can decrease the occurrence of symptomatic anastomotic leakage and should be routinely performed in all low anterior resections after 30 Gy/10 f/2 w preoperative radiotherapy.
Profiling β-thalassaemia mutations in India at state and regional levels: implications for genetic education, screening and counselling programmes
Authors: Sinha S. , Black M. L. , Agarwal S. , Colah R. , Das R. , Ryan K. , Bellgard M. , Bittles A. H. 
Published: February 2010

Abstract
Thalassaemia and sickle cell disease have been recognized by the World Health Organization as important inherited disorders principally impacting on the populations of low income countries. To create a national and regional profile of β-thalassaemia mutations in the population of India, a meta-analysis was conducted on 17 selected studies comprising 8,505 alleles and offering near-national coverage for the disease. At the national level 52 mutations accounted for 97.5% of all β-thalassaemia alleles, with IVSI-5(G>C) the most common disease allele (54.7%). Population stratification was apparent in the mutation profiles at regional level with, for example, the prevalence of IVSI-5(G>C) varying from 44.8% in the North to 71.4% in the East. A number of major mutations, such as Poly A(T>C), were apparently restricted to a particular region of the country, although these findings may in part reflect the variant test protocols adopted by different centres. Given the size and genetic complexity of the Indian population, and with specific mutations for β-thalassaemia known to be strongly associated with individual communities, comprehensive disease registries need to be compiled at state, district and community levels to ensure the efficacy of genetic education, screening and counselling programmes. At the same, time appropriately designed community-based studies are required as a health priority to correct earlier sampling inequities which resulted in the under-representation of many communities, in particular rural and socioeconomically under-privileged groups.