bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in the catalytic properties and substrate specificity of Bacillus sp. US149 maltogenic amylase by mutagenesis of residue 46
Authors: Ben Mabrouk Sameh , Ayadi-Zouari Dorra , Ben Hlima Hajer , Bejar Samir
Published: June 2013

Maltogenic amylase from Bacillus sp. US149 (MAUS149) is a cyclodextrin (CD)-degrading enzyme with a high preference for CDs over maltooligosaccharides. In this study, we investigated the roles of residue Asp46 in the specificity and catalytic properties of MAUS149 by using site-directed mutagenesis. Three mutated enzymes (D46V, D46G and D46N) were constructed and studied. The three mutants were found to be similar to the wild-type MAUS149 regarding thermoactivity, thermostability and pH profile. Nevertheless, the kinetic parameters for all the substrates of the mutant enzymes D46V and D46G were altered enormously as compared with those of the wild type. Indeed, the K  m values of MAUS149/D46G for all substrates were strongly increased. Nevertheless, the affinity and catalytic efficiency of MAUS149/D46V toward β-CD were increased fivefold as compared with those of MAUS149. Molecular modelling suggests that residue D46 forms a salt bridge with residue K282. This bond would maintain the arrangement of side chains of residues Y45 and W47 in a particular orientation that promotes access to the catalytic site and maintains the substrate therein. Hence, any replacement with uncharged amino acids influenced the flexibility of the gate wall at the substrate binding cleft resulting in changes in substrate selectivity.
Severity of psychosis syndrome and change of metabolic abnormality in chronic schizophrenia patients: Severe negative syndrome may be related to a distinct lipid pathophysiology
Authors: Chen S.-F. , Hu T.-M. , Lan T.-H. , Chiu H.-J. , Sheen L.-Y. , Loh E.-W.
Published: June 2013

Background:

Metabolic abnormality is common among schizophrenia patients. Some metabolic traits were found associated with subgroups of schizophrenia patients.

Objectives:

We examined a possible relationship between metabolic abnormality and psychosis profile in schizophrenia patients.

Method:

Three hundred and seventy-two chronic schizophrenia patients treated with antipsychotics for more than 2 years were assessed with the Positive and Negative Syndrome Scale. A set of metabolic traits was measured at scheduled checkpoints between October 2004 and September 2006.

Results:

Multiple regressions adjusted for sex showed negative correlations between body mass index (BMI) and total score and all subscales; triglycerides (TG) was negatively correlated with total score and negative syndrome, while HDLC was positively correlated with negative syndrome. When sex interaction was concerned, total score was negatively correlated with BMI but not with others; negative syndrome was negatively correlated with BMI and positively with HDLC. No metabolic traits were correlated with positive syndrome or general psychopathology.

Conclusions:

Loss of body weight is a serious health problem in schizophrenia patients with severe psychosis syndrome, especially the negative syndrome. Schizophrenia patients with severe negative syndrome may have a distinct lipid pathophysiology in comparison with those who were less severe in the domain.
Reproductive health information and abortion services: Standards developed by the European Court of Human Rights
Authors: Westeson Johanna
Published: June 2013

In 3 recent judgments, the European Court of Human Rights addressed the issue of access to abortion and related reproductive health services. In 2 of the judgments, the Court declared that the state violated women's rights by obstructing access to legal health services, including abortion. In so doing, it referred to the state's failure to implement domestic norms on prenatal testing and conscientious objection, and recognized the relevance of international medical guidelines. This illustrates that domestic and international medical standards can serve as critical guidance to human rights courts. In the third case, the Court showed its unwillingness to declare access to abortion a human right per se, which is troubling from the perspective of women's right to health and dignity. The present article outlines the relevance of these cases for the reproductive health profession and argues that medical professional societies can influence human rights courts by developing and enforcing medical standards, not only for the benefit of abortion rights domestically but also for the advancement of women's human rights worldwide.
Judging disease activity in rheumatoid arthritis by serum free kappa and lambda light chain levels
Authors: Ye Yun , Li Su‐Liang , Xie Ming , Jiang Ping , Liu Kai‐Ge , Li Ya‐Jun
Published: June 2013

The study aimed to evaluate the levels of serum free kappa (κ) and lambda (λ) light chains in patients with rheumatoid arthritis (RA) as well as exploring the association between serum free κ and λ light chains and activity of RA. For this purpose, healthy individuals and patients with active RA and RA in remission were enrolled, and their serum levels of free κ and λ light chains were measured using rate nephelometry. The diagnostic accuracy of serum free κ and λ light chains was evaluated by receiver operating characteristic curves and 95% confidence intervals for areas under the curve (AUC). The results obtained indicated that the levels of serum free κ and λ light chains in patients with active RA were significantly higher than those of patients in remission and of healthy controls (p < 0.05). Further, the AUC values in patients with active RA were 0.871 for free κ light chain and 0.781 for free λ light chain. When the optimal cut‐off point for serum κ light chain was 8.02 g/L, the maximum sensitivity and specificity were 82.5% and 82.5%, respectively, and when the optimal cut‐off point for serum λ light chain was 3.57 g/L, the maximum sensitivity and specificity were 80% and 82.5%, respectively. It was thus found that serum levels of free κ and λ light chains were positively correlated with disease activity in RA, the Disease Activity Score 28 (DAS28), and values for C‐reactive protein (CRP), erythrocyte sedimentation rate (ESR), platelet count (PLT), rheumatoid factor (RF), and anticitrullinated protein antibody (ACPA) (p < 0.05). In conclusion, high serum levels of free κ and λ light chains in patients with active RA are closely correlated with disease activity parameters including DAS28, CRP, ESR, PLT, RF, and ACPA. Thus, the above‐mentioned levels of serum free κ and λ light chains may be used as important indicators of activity of RA.
Combined effects of noise, vibration, and low temperature on the physiological parameters of labor employees
Authors: Chao Pao‐Chiang , Juang Yow‐Jer , Chen Chiou‐Jong , Dai Yu‐Tung , Yeh Ching‐Ying , Hu Ching‐Yao
Published: June 2013

Noise, vibration, and low temperature render specific occupational hazards to labor employees. The purpose of this research was to investigate the combined effects of these three physical hazards on employees' physiological parameters. The Taguchi experimental method was used to simulate different exposure conditions caused by noise, vibration, and low temperature, and their effects on the physiological parameters of the test takers were measured. The data were then analyzed using statistical methods to evaluate the combined effects of these three factors on human health. Results showed that the factor that influenced the finger skin temperature, manual dexterity, and mean artery pressure (MAP) most was air temperature, and exposure time was the second most influential factor. Noise was found to be the major factor responsible for hearing loss; in this case, hand–arm vibration and temperature had no effect at all. During the study, the temperature was confined in the 5–25°C range (which was not sufficient to study the effects at extremely high‐ and low‐temperature working conditions) because the combined effects of even two factors were very complicated. For example, the combined effects of hand–arm vibration and low temperature might lead to occupational hazards such as vibration‐induced white finger syndrome in working labors. Further studies concerning the occupational damage caused by the combined effects of hazardous factors need to be conducted in the future.
Double‐deleted vaccinia virus in virotherapy for refractory and metastatic pediatric solid tumors
Authors: Lun Xueqing , Ruan Yibing , Jayanthan Aarthi , Liu David J. , Singh Anjali , Trippett Tanya , Bell John , Forsyth Peter , Johnston Randal N. , Narendran Aru
Published: June 2013

Background

Previous studies have shown successful antitumor effects of systemically delivered double‐deleted vaccinia virus (vvDD) against a number of adult tumor models, including glioma, colon and ovarian cancers. The purpose of this study was to investigate the oncolytic potential of vvDD against a panel of cell lines representative of pediatric solid tumors that are currently difficult to cure.

Methods

Cell lines derived from central nervous system atypical teratoid rhabdoid tumor (AT/RT) (BT12, BT16 and KCCF1), sarcoma (143B, HOS, RD and RH30), and neuroblastoma (SKNAS, SKNBE2, IMR‐5 and IMR‐32) were examined for vvDD mediated cytotoxicity defined by virus expansion followed by loss of tumor cell viability. The normal human fibroblast cell line HS68 was used as a control. Next, relevant orthotopic, subcutaneous and lung metastasis xenograft models were treated with intravenous doses of live vvDD or killed virus controls (DV). Tumor growth inhibition and viral replication were quantified and survival outcomes of these animals were assessed.

Results

vvDD was able to infect and kill nine of eleven of the pediatric tumor cells (81.8%) in vitro. In xenograft models, intravenous administration of a single dose of vvDD significantly inhibited the growth of tumors and prolonged the survival of intracranial and metastatic tumors.

Conclusions

Oncolytic vvDD administered i.v. shows activity in preclinical models of pediatric malignancies that are resistant to many currently available treatments. Our data support further evaluation of vvDD virotherapy for refractory pediatric solid tumors.
Rate of Return to Acute Care Hospital Based on Day and Time of Rehabilitation Admission
Authors: Faulk Clinton E. , Cooper Natalie R. , Staneata Judit A. , Bunch Michael P. , Galang Enrique , Fang Xiangming , Foster Keith J.
Published: June 2013

Objective

To determine if a patient's return to the acute care hospital (RTACH) from an inpatient rehabilitation facility (IRF) because of medical acuity is affected by the day of the week and time of rehabilitation admission.

Design

Retrospective chart review.

Setting

Inpatient rehabilitation facility.

Participants

All adult patients admitted to the IRF from January 1, 2009, to June 30, 2011. RTACH was defined as an interruption in the patients' rehabilitation course as a result of medical and/or surgical complications requiring a higher level of care. The control group was defined as patients who completed an uninterrupted rehabilitation course. The study included 2282 patients (2026 control patients and 256 case patients).

Main Outcome Measures

We compared patient demographics, admission impairment groups, discharge diagnosis, admission and discharge Functional Independent Measure (FIM) scores, length of stay, attached hospital versus outside hospital admissions, and RTACH rates between case patients and control patients.

Results

Out of 2282 patients admitted to the IRF over a 30‐month period, 256 patients (10.85%) required an RTACH for a higher level of care not available in the IRF. Two statistically significant results were found for RTACH, including rehabilitation admission time and FIM scores (admission motor and cognition scores). Day of the week for inpatient rehabilitation admission was not statistically significant.

Conclusion

This study found that the later in the day a patient was admitted to the IRF, the higher the rate of RTACH. In addition, a lower Motor FIM score was found to be correlated with a higher rate of RTACH. Admission day of the week was not found to be statistically significant with regard to the rate of RTACH. Further research is needed to determine the underlying contributing factors that would help decrease the rate of RTACH.
Koopman-mode decomposition of the cylinder wake
Authors: Bagheri Shervin
Published: June 2013

The Koopman operator provides a powerful way of analysing nonlinear flow dynamics using linear techniques. The operator defines how observables evolve in time along a nonlinear flow trajectory. In this paper, we perform a Koopman analysis of the first Hopf bifurcation of the flow past a circular cylinder. First, we decompose the flow into a sequence of Koopman modes, where each mode evolves in time with one single frequency/growth rate and amplitude/phase, corresponding to the complex eigenvalues and eigenfunctions of the Koopman operator, respectively. The analytical construction of these modes shows how the amplitudes and phases of nonlinear global modes oscillating with the vortex shedding frequency or its harmonics evolve as the flow develops and later sustains self-excited oscillations. Second, we compute the dynamic modes using the dynamic mode decomposition (DMD) algorithm, which fits a linear combination of exponential terms to a sequence of snapshots spaced equally in time. It is shown that under certain conditions the DMD algorithm approximates Koopman modes, and hence provides a viable method to decompose the flow into saturated and transient oscillatory modes. Finally, the relevance of the analysis to frequency selection, global modes and shift modes is discussed.
Chronic high-fat diet increases acute neuroendocrine stress response independently of prenatal dexamethasone treatment in male rats
Authors: Abildgaard Anders , Lund Sten , Hougaard Karin S
Published: June 2013

Objective

Intrauterine growth restriction (IUGR) has been associated with metabolic disorders later in life such as obesity and diabetes as well as psychiatric disorders such as depression and schizophrenia. Therefore, we wanted to investigate whether behavioural, metabolic or neuroendocrine abnormalities could be provoked or exacerbated by a high-fat diet (HFD) in an experimental model of IUGR.

Methods

Pregnant dams were exposed to dexamethasone (DEX) in the third gestational week to induce IUGR. Late adolescent male offspring of DEX- and vehicle-treated dams were then fed a HFD or standard chow for 8 weeks and subjected to a variety of assessments.

Results

Only diet affected the hypothalamus-pituitary-adrenal (HPA) axis stress response, as HFD doubled the observed corticosterone levels following acute restraint. HFD and prenatal DEX exposure concomitantly exacerbated depressive-like behaviour in the forced swim test, even though no interaction was seen. Prenatal DEX treatment tended to increase the basal acoustic startle response (ASR), while an interaction between HFD and DEX was present in the ASR pre-pulse inhibition suggestive of fundamental changes in neuronal gating mechanisms. Metabolic parameters were only affected by diet, as HFD increased fasting glucose and insulin levels.

Conclusion

We conclude that chronic HFD may be more important in programming of the HPA axis stress responsiveness than an adverse foetal environment and therefore potentially implies an increased risk for developing psychiatric and metabolic disease.
Dopamine D2/3 receptor availability and human cognitive impulsivity: a high-resolution positron emission tomography imaging study with [11C]raclopride
Authors: Kim Jong-Hoon , Son Young-Don , Kim Hang-Keun , Lee Sang-Yoon , Kim Young-Bo , Cho Zang-Hee
Published: June 2013

Objective

Human impulsivity is a complex multidimensional construct encompassing cognitive, emotional, and behavioural aspects. Previous animal studies have suggested that striatal dopamine receptors play a critical role in impulsivity. In this study, we investigated the relationship between self-reported impulsiveness and dopamine D2/3 receptor availability in striatal subdivisions in healthy subjects using high-resolution positron emission tomography (PET) with [11C]raclopride.

Methods

Twenty-one participants completed 3-T magnetic resonance imaging and high-resolution PET scans with [11C]raclopride. The trait of impulsiveness was measured using the Barratt Impulsiveness Scale (BIS-11). Partial correlation analysis was performed between BIS-11 scores and D2/3 receptor availability in striatal subregions, controlling for the confounding effects of temperament characteristics that are conceptually or empirically related to dopamine, which were measured by the Temperament and Character Inventory.

Results

The analysis revealed that the non-planning (p = 0.004) and attentional (p = 0.007) impulsiveness subscale scores on the BIS-11 had significant positive correlations with D2/3 receptor availability in the pre-commissural dorsal caudate. There was a tendency towards positive correlation between non-planning impulsiveness score and D2/3 receptor availability in the post-commissural caudate.

Conclusion

These results suggest that cognitive subtrait of impulsivity is associated with D2/3 receptor availability in the associative striatum that plays a critical role in cognitive processes involving attention to detail, judgement of alternative outcomes, and inhibitory control.
Dealing with the Principle of Proportionality in Armed Conflict in Retrospect: The Application of the Principle in International Criminal Trials
Authors: Bartels Rogier
Published: June 2013

The principle of proportionality is one of the core principles of international humanitarian law. The principle is not easy to apply on the battlefield, but is even harder to apply retrospectively, in the courtroom. This article discusses the challenges in applying the principle during international criminal trials. It discusses the principle itself, followed by an explanation of the general challenges of dealing with violations of international humanitarian law, and more specifically the rules related to the conduct of hostilities, during war crime trials. The way in which the principle has been used before the International Criminal Tribunal for the former Yugoslavia is examined, including an in-depth discussion of the recentGotovinacase. The second part consists of an evaluation of Article 8(2)(b)(iv) of the Rome Statute of the International Criminal Court, and discusses the difficulties the International Criminal Court would face in cases dealing with violations of the principle of proportionality.
Linear and nonlinear stability criteria for compressible MHD flows in a gravitational field
Authors: MOAWAD S. M.
Published: June 2013

The equilibrium and stability properties of ideal magnetohydrodynamics (MHD) of compressible flow in a gravitational field with a translational symmetry are investigated. Variational principles for the steady-state equations are formulated. The MHD equilibrium equations are obtained as critical points of a conserved Lyapunov functional. This functional consists of the sum of the total energy, the mass, the circulation along field lines (cross helicity), the momentum, and the magnetic helicity. In the unperturbed case, the equilibrium states satisfy a nonlinear second-order partial differential equation (PDE) associated with hydrodynamic Bernoulli law. The PDE can be an elliptic or a parabolic equation depending on increasing the poloidal flow speed. Linear and nonlinear Lyapunov stability conditions under translational symmetric perturbations are established for the equilibrium states.
CONNECTIONS AND NETWORKS IN SPAIN OF A LONDON MERCHANT-BANKER, 1800-1850
Authors: Llorca-Jaña Manuel
Published: June 2013

This paper deals with Anglo-Spanish trade and finances for the period c. 1810-1850. It concentrates on the business activities of a London merchant bank (Huth & Co. or Huth) with Spain during this period by paying special attention to the support given by Huth to the many bilateral trades between Spain and Britain in which the company participated. It also focuses on the support given by Huth to much trade in and out of Spanish ports but which did not go through British ports. This overall support included the provision of credit facilities, exchange rate brokerage, insurance services and commercial intelligence. In addition, the article covers the links between Huth and the Spanish crown, thanks to which the bank became an important conduit of Spanish investments in American securities before 1850. Huth was also the paymaster abroad for the Spanish state. In view of Huth's close connections to the Spanish economy during this period, it is perhaps surprising that this is the first study of this «Spanish» house in London.
COST-EFFECTIVENESS OF CONTINUOUS-FLOW LEFT VENTRICULAR ASSIST DEVICES
Authors: Neyt Mattias , Van den Bruel Ann , Smit Yolba , De Jonge Nicolaas , Erasmus Michiel , Van Dijk Diederik , Vlayen Joan
Published: June 2013

Objectives: Mechanical circulatory support through left ventricular assist devices (LVADs) improves survival and quality of life for patients with end-stage heart failure who are ineligible for cardiac transplantation. Our aim was to calculate the cost-effectiveness of continuous-flow LVADs.

Methods: A cost-utility analysis from a societal perspective was performed. A lifetime Markov model was set up in which continuous-flow LVAD was compared with optimal medical therapy (OMT). The treatment effect was modeled indirectly combining the results of the REMATCH trial comparing OMT with a pulsatile-flow LVAD and the HeartMate II Destination Therapy Trial comparing a pulsatile-flow LVAD with a continuous-flow LVAD. Cost data were based on real-world financial data of sixty-nine patients with a HeartMate II implantation from the University Medical Centre Utrecht (the Netherlands). One-way and probabilistic sensitivity analyses were performed.

Results: Comparing the continuous-flow HeartMate II with OMT, 3.23 (95 percent confidence interval [CI], 2.18–4.49) life-years were gained (LYG) or 2.83 (95 percent CI, 1.91–3.90) quality-adjusted life-years (QALYs). The cost of an LVAD implant was approximately €126,000, of which the device itself represented the largest cost, being €70,000. Total incremental costs amounted to €299,100 (95 percent CI, 190,500–521,000). This resulted in an incremental cost-effectiveness ratio of €94,100 (95 percent CI, 59,100–160,100) per LYG or €107,600 (95 percent CI, 66,700–181,100) per QALY. Sensitivity analyses showed these results were robust.

Conclusions: Although LVAD destination therapy improves survival and quality of life, it remains a relatively expensive intervention which renders the reimbursement of this therapy questionable.
ATTENTION TO IRREGULAR VERBS BY BEGINNING LEARNERS OF GERMAN
Authors: Godfroid Aline , Uggen Maren S.
Published: June 2013

This study focuses on beginning second language learners’ attention to irregular verb morphology, an area of grammar that many adults find difficult to acquire (e.g., DeKeyser, 2005; Larsen-Freeman, 2010). We measured beginning learners’ eye movements during sentence processing to investigate whether or not they actually attend to irregular verb features and, if so, whether the amount of attention that they pay to these features predicts their acquisition. On the assumption that attention facilitates learning (e.g., Gass, 1997; Robinson, 2003; Schmidt, 2001), we expected more attention (i.e., longer fixations or more frequent comparisons between verb forms) to lead to more learning of the irregular verbs. Forty beginning learners of German read 12 German sentence pairs with stem-changing verbs and 12 German sentence pairs with regular verbs while an Eyelink 1000 recorded their eye movements. The stem-changing verbs consisted of sixa→ächanging verbs and sixe→i(e)changing verbs. Each verb appeared in a baseline sentence in the first-person singular, which has no stem change, and a critical sentence in the second- or third-person singular, which have a stem change for the irregular but not the regular verbs, on the same screen. Productive pre- and posttests measured the effects of exposure on learning. Results indicate that learners looked longer overall at stem-changing verbs than regular verbs, revealing a late effect of verb irregularity on reading times. Longer total times had a modest, favorable effect on the subsequent production of the stem vowel. Finally, the production of only thea→äverbs—not thee→i(e)verbs—benefited from direct visual comparisons during reading, possibly because of the umlaut in the former. We interpret the results with reference to recent theory and research on attention, noticing, and language learning and provide a more nuanced and empirically based understanding of the noticing construct.
ECOLOGICAL VALIDITY IN EYE-TRACKING
Authors: Spinner Patti , Gass Susan M. , Behney Jennifer
Published: June 2013

Eye-trackers are becoming increasingly widespread as a tool to investigate second language (L2) acquisition. Unfortunately, clear standards for methodology—including font size, font type, and placement of interest areas—are not yet available. Although many researchers stress the need for ecological validity—that is, the simulation of natural reading conditions—it may not be prudent to use such a design to investigate new directions in eye-tracking research, and particularly in research involving small lexical items such as articles. In this study, we examine whether two different screen layouts can lead to different results in an eye-tracking study on the L2 acquisition of Italian gender. The results of an experiment with an ecologically valid design are strikingly different than the results of an experiment with a design tailored to track eye movements to articles. We conclude that differences in screen layout can have significant effects on results and that it is crucial that researchers report screen layout information.
Ecological Validity and Neuroanatomical Correlates of the NIH EXAMINER Executive Composite Score
Authors: Possin Katherine L. , LaMarre Amanda K. , Wood Kristie A. , Mungas Dan M. , Kramer Joel H.
Published: June 2013

Executive functions refer to a constellation of higher-level cognitive abilities that enable goal-oriented behavior. The NIH EXAMINER battery was designed to assess executive functions comprehensively and efficiently. Performance can be summarized by a single score, the “Executive Composite,” which combines measures of inhibition, set-shifting, fluency, and working memory. We evaluated the ecological validity of the Executive Composite in a sample of 225 mixed neurological patients and controls using the Frontal Systems Behavior Scale (FrSBe), an informant-based measure of real-world executive behavior. In addition, we investigated the neuroanatomical correlates of the Executive Composite using voxel-based morphometry in a sample of 37 participants diagnosed with dementia, mild cognitive impairment, or as neurologically healthy. The Executive Composite accounted for 28% of the variance in Frontal Systems Behavior Scale scores beyond age. Even after including two widely used executive function tests (Trails B and Stroop) as covariates, the Executive Composite remained a significant predictor of real-world behavior. Anatomically, poorer scores on the Executive Composite were associated with smaller right and left dorsolateral prefrontal volumes, brain regions critical for good executive control. Taken together, these results suggest that the Executive Composite measures important aspects of executive function not captured by standard measures and reflects the integrity of frontal systems. (JINS, 2013,19, 1–9)
Atomic Force Microscopy Characterization of the External Cortical Bone Surface in Young and Elderly Women: Potential Nanostructural Traces of Periosteal Bone Apposition During Aging
Authors: Milovanovic Petar , Djuric Marija , Neskovic Olivera , Djonic Danijela , Potocnik Jelena , Nikolic Slobodan , Stoiljkovic Milovan , Zivkovic Vladimir , Rakocevic Zlatko
Published: June 2013

On the basis of the suggestion that bone nanostructure bears “tissue age” information and may reflect surface deposition/modification processes, we performed nanoscale characterization of the external cortical bone surface at the femoral neck in women using atomic force microscopy (AFM). The specific aims were to assess age-related differences in bone nanostructure and explore the existence of nanostructural traces of potential bone apposition at this surface. Our findings revealed that the external cortical surface represents a continuous phase composed of densely packed mineral grains. Although the grains varied in size and shape, there was a domination of small grains indicative of freshly deposited bone (mean grain size: young, 35 nm; old, 37 nm;p> 0.05). Advanced quantitative analysis of surface morphological patterns revealed comparable roughness and complexity of the surface, suggesting a similar rate of mineral particle deposition at the surface in both groups. Calcium/phosphorus ratio, a measure of bone tissue age, was within the same range in both groups. In summary, our AFM analyses showed consistent nanostructural and compositional bone features, suggesting existence of new bone at the periosteal bone surface in both young and elderly women. Considering observed age-related increase in the neck diameter, AFM findings may support the theory of continuous bone apposition at the periosteal surface.
Seaside transportation—from structure to function of translocation machines
Authors: Lithgow Trevor , Waksman Gabriel
Published: June 2013

The EMBO conference ‘From Structure to Function of Translocation Machines’ took place in April 2013 in Dubrovnik, Croatia. The meeting brought together a mix of established and aspiring researchers to discuss a wealth of unpublished data and ideas in a lively scientific programme of talks designed to shatter the established dogma. From new ways to envisage known protein transport pathways to a brand new and totally unconventional protein transport system, surprises were part and parcel of this excellent EMBO conference.
Rejuvenating Tithonus
Authors: Loh Kyle M , Lim Bing
Published: June 2013

Four recent publications, including one in this issue by Surani and colleagues, report that Prdm14 preserves the pluripotent stem cell state by inhibiting FGF signalling and global DNA methylation.
Sex determination
Authors: Mittwoch Ursula
Published: June 2013

How the sex of offspring is determined has puzzled philosophers and scientists for millennia. Modern science has identified both genetic and environmental factors, but the question is still not yet fully answered.
Dynamics and stoichiometry of a regulated enhancer-binding protein in live Escherichia coli cells
Authors: Mehta Parul , Jovanovic Goran , Lenn Tchern , Bruckbauer Andreas , Engl Christoph , Ying Liming , Buck Martin
Published: June 2013

Bacterial enhancer-dependent transcription systems support major adaptive responses and offer a singular paradigm in gene control analogous to complex eukaryotic systems. Here we report new mechanistic insights into the control of one-membrane stress-responsive bacterial enhancer-dependent system. Using millisecond single-molecule fluorescence microscopy of live cells we determine the localizations, two-dimensional diffusion dynamics and stoichiometries of complexes of the bacterial enhancer-binding ATPase PspF during its action at promoters as regulated by inner membrane interacting negative controller PspA. We establish that a stable repressive PspF–PspA complex is located in the nucleoid, transiently communicating with the inner membrane via PspA. The PspF as a hexamer stably binds only one of the two psp promoters at a time, suggesting that psp promoters will fire asynchronously and cooperative interactions of PspF with the basal transcription complex influence dynamics of the PspF hexamer–DNA complex and regulation of the psp promoters.
Proximity-coupled Ti/TiN multilayers for use in kinetic inductance detectors
Authors: Vissers Michael R. , Gao Jiansong , Sandberg Martin , Duff Shannon M. , Wisbey David S. , Irwin Kent D. , Pappas David P.
Published: June 2013

We apply the superconducting proximity effect in TiN/Ti multi-layer films to tune the critical temperature, TC, to within 10 mK with high uniformity (less than 15 mK spread) across a 75 mm wafer. Reproducible TC’s are obtained from 0.8 to 2.5 K. These films had high resistivities, >100μΩ cm, and internal quality factors for resonators in the GHz range, on the order of 100 k and higher. Trilayers of both TiN/Ti/TiN and thicker superlattice films were prepared, demonstrating a well controlled process for films over a wide thickness range. Detectors were fabricated and shown to have single photon resolution at 1550 nm. The high uniformity and controllability coupled with the high quality factor, kinetic inductance, and inertness of TiN make these films ideal for use in frequency multiplexed kinetic inductance detectors and potentially other applications such as nanowire detectors, transition edge sensors, and associated quantum information applications.
Technical review and economic assessment of ground source heat pump utilization in Taleghan-Iran
Authors: Rashidi R. , Shariati A. , Moravvej Z. , Shiroudi A.
Published: June 2013

GSHP (through ground source heat pump) has been considered as one of the proposed solutions for the convenient energy supply for cooling and heating systems in recent decades. In Iran, the renewable energy organization as the pioneer organization is involved in localization and utilization of renewable energies. It has developed and installed some of these systems in various parts of the country. In this paper, the fundamentals of GSHPs and some related projects in Iran are reviewed. Then, GSHP is compared with commercially available heating/cooling split units economically. Results show that although the return of investment may take a long period, the GSHP units are profitable.
Crystallization in a sheared colloidal suspension
Authors: Lander Boris , Seifert Udo , Speck Thomas
Published: June 2013

We study numerically the crystallization process in a supersaturated suspension of repulsive colloidal particles driven by simple shear flow. The effect of the shear flow on crystallization is two-fold: while it suppresses the initial nucleation, once a large enough critical nucleus has formed its growth is enhanced by the shear flow. Combining both effects implies an optimal strain rate at which the overall crystallization rate has a maximum. To gain insight into the underlying mechanisms, we employ a discrete state model describing the transitions between the local structural configurations around single particles. We observe a time-scale separation between these transitions and the overall progress of the crystallization allowing for an effective Markovian description. By using this model, we demonstrate that the suppression of nucleation is due to the inhibition of a pre-structured liquid.
Communication: An inexpensive, variational, almost black-box, almost size-consistent correction to configuration interaction singles for valence excited states
Authors: Liu Xinle , Ou Qi , Alguire Ethan , Subotnik Joseph E.
Published: June 2013

Configuration interaction singles (CIS) describe excited electronic states only qualitatively and improvements are imperative as a means of recovering chemical accuracy. In particular, variational improvements would be ideal to account for state crossings and electronic relaxation. To accomplish such an objective, in this communication we present a new suite of algorithms, abbreviated VOO-CIS for variationally orbital optimized CIS. We show below that VOO-CIS yields a uniform improvement to CIS, rebalancing the energies of CT states versus non-CT states within the same framework. Furthermore, VOO-CIS finds energetic corrections for CT states that are even larger than those predicted by CIS(D). The computational cost of VOO-CIS depends strongly on the number of excited states requested (n), but otherwise should be proportional to the cost of CIS itself.
Development of an (e,2e) electron momentum spectroscopy apparatus using an ultrashort pulsed electron gun
Authors: Yamazaki M. , Kasai Y. , Oishi K. , Nakazawa H. , Takahashi M.
Published: June 2013

An (e,2e) apparatus for electron momentum spectroscopy (EMS) has been developed, which employs an ultrashort-pulsed incident electron beam with a repetition rate of 5 kHz and a pulse duration in the order of a picosecond. Its instrumental design and technical details are reported, involving demonstration of a new method for finding time-zero. Furthermore, EMS data for the neutral Ne atom in the ground state measured by using the pulsed electron beam are presented to illustrate the potential abilities of the apparatus for ultrafast molecular dynamics, such as by combining EMS with the pump-and-probe technique.
Combined synchrotron X-ray tomography and X-ray powder diffraction using a fluorescing metal foil
Authors: Kappen P. , Arhatari B. D. , Luu M. B. , Balaur E. , Caradoc-Davies T.
Published: June 2013

This study realizes the concept of simultaneous micro-X-ray computed tomography and X-ray powder diffraction using a synchrotron beamline. A thin zinc metal foil was placed in the primary, monochromatic synchrotron beam to generate a divergent wave to propagate through the samples of interest onto a CCD detector for tomographic imaging, thus removing the need for large beam illumination and high spatial resolution detection. Both low density materials (kapton tubing and a piece of plant) and higher density materials (Egyptian faience) were investigated, and elemental contrast was explored for the example of Cu and Ni meshes. The viability of parallel powder diffraction using the direct beam transmitted through the foil was demonstrated. The outcomes of this study enable further development of the technique towards in situ tomography/diffraction studies combining micrometer and crystallographic length scales, and towards elemental contrast imaging and reconstruction methods using well defined fluorescence outputs from combinations of known fluorescence targets (elements).
Experimental evidence of ion acoustic soliton chain formation and validation of nonlinear fluid theory
Authors: Kakad Amar , Omura Yoshiharu , Kakad Bharati
Published: June 2013

We perform one-dimensional fluid simulation of ion acoustic (IA) solitons propagating parallel to the magnetic field in electron-ion plasmas by assuming a large system length. To model the initial density perturbations (IDP), we employ a KdV soliton type solution. Our simulation demonstrates that the generation mechanism of IA solitons depends on the wavelength of the IDP. The short wavelength IDP evolve into two oppositely propagating identical IA solitons, whereas the long wavelength IDP develop into two indistinguishable chains of multiple IA solitons through a wave breaking process. The wave breaking occurs close to the time when electrostatic energy exceeds half of the kinetic energy of the electron fluid. The wave breaking amplitude and time of its initiation are found to be dependent on characteristics of the IDP. The strength of the IDP controls the number of IA solitons in the solitary chains. The speed, width, and amplitude of IA solitons estimated during their stable propagation in the simulation are in good agreement with the nonlinear fluid theory. This fluid simulation is the first to confirm the validity of the general nonlinear fluid theory, which is widely used in the study of solitary waves in laboratory and space plasmas.
Laser red shifting based characterization of wakefield excitation in a laser-plasma accelerator
Authors: Shiraishi S. , Benedetti C. , Gonsalves A. J. , Nakamura K. , Shaw B. H. , Sokollik T. , van Tilborg J. , Geddes C. G. R. , Schroeder C. B. , Tóth Cs. , Esarey E. , Leemans W. P.
Published: June 2013

Optical spectra of a drive laser exiting a channel guided laser-plasma accelerator (LPA) are analyzed through experiments and simulations to infer the magnitude of the excited wakefields. The experiments are performed at sufficiently low intensity levels and plasma densities to avoid electron beam generation via self-trapping. Spectral redshifting of the laser light is studied as an indicator of the efficiency of laser energy transfer into the plasma through the generation of coherent plasma wakefields. Influences of input laser energy, plasma density, temporal and spatial laser profiles, and laser focal location in a plasma channel are analyzed. Energy transfer is found to be sensitive to details of laser pulse shape and focal location. The experimental conditions for these critical parameters are modeled and included in particle-in-cell simulations. Simulations reproduce the redshift of the laser within uncertainties of the experiments and produce an estimate of the wake amplitudes in the experiments as a function of amount of redshift. The results support the practical use of laser redshifting to quantify the longitudinally averaged accelerating field that a particle would experience in an LPA powered below the self-trapping limit.
Electronic, thermoelectric, and magneto-dielectric properties of Ca1−xNaxCr2O4
Authors: Kolodiazhnyi Taras , Sakurai Hiroya
Published: June 2013

We report on electronic, thermoelectric, and magneto-dielectric properties of Ca1−xNaxCr2O4 series with a calcium ferrite-type structure prepared by high-pressure-high-temperature synthesis. Dielectric spectroscopy down to 2 K confirms that both CaCr2O4 and NaCr2O4 end members have an insulating ground state notwithstanding the fact that the latter compound has a mixed valence Cr3+/Cr4+ structure. A crossover from positive to negative charge carriers occurs in NaCr2O4 at T≈230 K. Partial substitution of Ca for Na brings about a change from n to p type carriers at ca. x=0.75. A strong suppression of thermal conductivity below TN=21 K was found in CaCr2O4 indicating a scattering of acoustic phonons from a long wave-length cycloidal magnetic excitations. A pronounced dielectric anomaly at Néel temperature adds CaCr2O4 to the multiferroic family of compounds. Lattice contribution to dielectric properties of NaCr2O4 at TN=125 K is screened by high electric conductivity. An onset of the magnetocapacitance above 3 T correlates with the spin-flop transition in NaCr2O4 at a critical field of 3.5 T. A strong non-saturated magnetocapacitance in this compound cannot be entirely attributed to the colossal magnetoresistance.
Intraband carrier dynamics in InAs/GaAs quantum dots stimulated by bound-to-continuum excitation
Authors: Harada Yukihiro , Maeda Tsuyoshi , Kita Takashi
Published: June 2013

We studied state-filling-dependent intraband carrier dynamics in InAs/GaAs self-assembled quantum dots using two-color photoexcitation spectroscopy. The photoluminescence (PL) intensity was observed to be dramatically reduced by selectively pumping carriers from the intermediate state to the continuum state located above the conduction band edge, and the PL-intensity reduction decreased with an increase in the continuous-wave excitation power. We analyzed the observed state-filling-dependent intraband carrier dynamics by detailed modeling of carrier excitation and relaxation processes in which the two-photon absorption for the interband transition, Pauli blocking, and saturable absorption for the intraband transition is considered.
Breakdown of the Debye polarization ansatz at protein-water interfaces
Authors: Fernández Stigliano Ariel
Published: June 2013

The topographical and physico-chemical complexity of protein-water interfaces scales down to the sub-nanoscale range. At this level of confinement, we demonstrate that the dielectric structure of interfacial water entails a breakdown of the Debye ansatz that postulates the alignment of polarization with the protein electrostatic field. The tendencies to promote anomalous polarization are determined for each residue type and a particular kind of structural defect is shown to provide the predominant causal context.
Dephasing of Si singlet-triplet qubits due to charge and spin defects
Authors: Culcer Dimitrie , Zimmerman Neil M.
Published: June 2013

We study the effect of charge and spin noise on singlet-triplet qubits in Si quantum dots. We set up a theoretical framework aimed at enabling experiment to efficiently identify the most deleterious defects, and complement it with the knowledge of defects gained in decades of industrial and academic work. We relate the dephasing rates Γϕ due to various classes of defects to experimentally measurable parameters, such as charge dipole moment, spin dipole moment, and fluctuator switching times. We find that charge fluctuators are more efficient in causing dephasing than spin fluctuators.
Resonant ultrasound spectroscopy of defects: Case study of flat-bottomed holes
Authors: Solodov Igor , Bai Juxing , Busse Gerd
Published: June 2013

Unlike conventional resonant ultrasonic spectroscopy aimed at determining elastic constants and related parameters of solids, resonant ultrasound spectroscopy of defects (RUSOD) addresses an opportunity to detect, visualize, and classify mechanical defects in materials. The approach is based on the resonant ultrasonic wave-defect interaction due to local defect resonance. RUSOD is shown to be defect- and frequency selective imaging technique capable of distinguishing between different defects by variation of ultrasonic frequency.
A bi-functional structure with tunable electrical and optical properties for organic photovoltaic cells
Authors: Luo D. Y. , Yu L. M. , Man J. X. , Liu T. L. , Li J. J. , Xu T. , Liu Z. , Wang Z. B. , Lu Z. H.
Published: June 2013

We have successfully developed a C60:LiF/BCP (bathocuproine) bilayer-buffer structure to optimize both the light absorption enhancement and the exciton-blocking at the cathode interface of a small molecular photovoltaic cell based on the archetypical CuPc/C60 structure. The function of the C60:LiF layer is to serve as an optical spacer and is found to yield a peak power conversion efficiency (PCE) with a 50 wt. % LiF at a thickness of 30 nm. A BCP layer is added between the optimized C60:LiF layer and the Al metal electrode to function as a barrier for excitons. This combined bilayer-buffer structure yields an optimal performance in short circuit current (Jsc) and PCE. A detailed study using a single carrier electron-only structure and a numerical simulation of optical electric-field distribution suggests that C60:LiF layer enhances light absorption at long wavelengths.
Effects of the non-uniform initial environment and the guide field on the plasmoid instability
Authors: Ni Lei , Lin Jun , Murphy Nicholas A.
Published: June 2013

Effects of non-uniform initial mass density and temperature on the plasmoid instability are studied via 2.5-dimensional resistive magnetohydrodynamic (MHD) simulations. Our results indicate that the development of the plasmoid instability is apparently prevented when the initial plasma density at the center of the current sheet is higher than that in the upstream region. As a result, the higher the plasma density at the center and the lower the plasma β in the upstream region, the higher the critical Lundquist number needed for triggering secondary instabilities. When β=0.2, the critical Lundquist number is higher than 104. For the same Lundquist number, the magnetic reconnection rate is lower for the lower plasma β case. Oppositely, when the initial mass density is uniform and the Lundquist number is low, the magnetic reconnection rate turns out to be higher for the lower plasma β case. For the high Lundquist number case (>104) with uniform initial mass density, the magnetic reconnection is not affected by the initial plasma β and the temperature distribution. Our results indicate that the guide field has a limited impact on the plasmoid instability in resistive MHD.