bluuebunny/crossref_metadata_2025 huggingface dataset:
Glutathione‐S‐transferase P1 may predispose children to a decline in pulmonary function after stem cell transplant
Authors: Stark Julie , Renbarger Jamie , Slaven James , Yu Zhangsheng , Then Jenny , Skiles Jodi , Davis Stephanie
Published: February 2017

RATIONALE

Pulmonary complications after hematopoietic stem cell transplant (SCT) are associated with increased mortality. Genetic markers for those at risk for pulmonary impairment post‐SCT have not been widely investigated.

METHODS

Forty‐nine patients were retrospectively selected from a single institution's biorepository with linked clinical data. All subjects performed pre‐SCT PFTs. Genotyping was conducted using the Infinium Exome‐24 BeadChip. Four single nucleotide polymorphisms (SNPs) were selected (rs1800871, rs1695, rs1800629, rs12477314) and evaluated for association with PFT parameters as change over time from baseline. Associations between SNPs and PFT parameters were assessed and adjusted for the following confounding variables: age, gender, and race.

RESULTS

Using the recessive genetic model, patients with one or two minor alleles for the glutathione S‐transferase P1 (GSTP1) SNP rs1695 had a lower decline in FEV1 and FEF25‐75 at 1‐year post‐SCT compared to patients who were homozygous for the ancestral allele (adjusted P‐values <0.01 and 0.02, respectively). No other SNPs were significantly associated with other PFT parameters.

CONCLUSIONS

Our findings suggest that GSTP1 genotype may be associated with lung function during the first year post‐SCT. Identifying and investigating genes that predispose patients to pulmonary complications after SCT may allow for more personalized patient management based on pre‐emptive genetic testing. The glutathione S‐transferase gene merits further investigation.
Specific Capture of Peptide‐Receptive Major Histocompatibility Complex Class I Molecules by Antibody Micropatterns Allows for a Novel Peptide‐Binding Assay in Live Cells
Authors: Dirscherl Cindy , Palankar Raghavendra , Delcea Mihaela , Kolesnikova Tatiana A. , Springer Sebastian
Published: February 2017

Binding assays with fluorescently labeled ligands and recombinant receptor proteins are commonly performed in 2D arrays. But many cell surface receptors only function in their native membrane environment and/or in a specific conformation, such as they appear on the surface of live cells. Thus, receptors on live cells should be used for ligand binding assays. Here, it is shown that antibodies preprinted on a glass surface can be used to specifically array a peptide receptor of the immune system, i.e., the major histocompatibility complex class I molecule H‐2Kb, into a defined pattern on the surface of live cells. Monoclonal antibodies make it feasible to capture a distinct subpopulation of H‐2Kb and hold it at the cell surface. This patterned receptor enables a novel peptide‐binding assay, in which the specific binding of a fluorescently labeled index peptide is visualized by microscopy. Measurements of ligand binding to captured cell surface receptors in defined confirmations apply to many problems in cell biology and thus represent a promising tool in the field of biosensors.
Influence of chorionicity and gestational age at single fetal loss on risk of preterm birth in twin pregnancy: analysis of STORK multiple pregnancy cohort
Authors: D'Antonio F. , Thilaganathan B. , Dias T. , Khalil A. ,   on behalf of the Southwest Thames Obstetric Research Collaborative (STORK)
Published: February 2017

Objective

Single intrauterine death (sIUD) in twin pregnancy is associated with a significant risk of cotwin demise and preterm birth (PTB), especially in monochorionic (MC) twins. However, it is yet to be established whether the gestational age at loss may influence the pregnancy outcome. The aim of this study was to explore the risk of PTB according to the gestational age at diagnosis of sIUD.

Methods

This was a cohort study of all twin pregnancies booked for antenatal care in a large regional network of nine hospitals over a 10‐year period. Ultrasound data were matched to hospital delivery records and to a mandatory national register for stillbirth and neonatal loss provided by the Centre for Maternal and Child Enquires. Cases with double fetal loss at the time of the scan and cases of sIUD occurring at or after 34 weeks of gestation were not included in the analysis. The relative risk (RR) of PTB at < 34, < 32 and < 28 weeks of gestation in twin pregnancies complicated by sIUD was assessed and compared with that in twin pregnancies without fetal loss. The risk of PTB at < 34 weeks was stratified according to the gestational age at diagnosis of sIUD. The risk of PTB in twin pregnancy after sIUD according to the gestational age at death was also explored.

Results

The analysis included 3013 twin gestations (2469 dichorionic (DC) and 544 MC). Median gestational age at birth was lower in the pregnancies complicated by sIUD compared with those that were not (32.0 weeks: interquartile range (IQR), 29.0–34.3 weeks vs 36.7 weeks: IQR, 35.0–37.6; P < 0.001) and this difference persisted when stratifying the data according to chorionicity (P < 0.0001 for both MC and DC pregnancies). The risk of PTB at < 34 weeks (RR, 4.3 (95% CI, 3.5–5.2)), < 32 weeks (RR, 6.1 (95% CI, 4.6–8.1)) and < 28 weeks (RR, 12.4 (95% CI, 6.9–22.2)) of gestation was higher in pregnancies complicated by sIUD compared with those which did not experience fetal loss. This association was observed both in MC and DC twin gestations. When compared with DC pregnancies, MC twins affected by sIUD were not at significantly increased risk of PTB before either 34, 32 or 28 weeks of gestation. The risk of PTB at < 34 weeks of gestation was higher when the sIUD occurred at a later gestational age (chi‐square test for trend, P < 0.001).

Conclusions

Twin pregnancies complicated by sIUD, regardless of the chorionicity, have a significantly higher risk of PTB at < 34, < 32 and < 28 weeks of gestation. The risk of PTB at < 34 weeks of gestation was higher when the sIUD occurred in the second half of the pregnancy. Large prospective multicenter studies with shared protocols for prenatal management are needed to ascertain the actual risk of spontaneous PTB in twin pregnancies affected by sIUD. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.
Technical note: Option‐based costing and the volatility portfolio
Authors: de Treville Suzanne , Cattani Kyle , Saarinen Lauri
Published: February 2017

It has been clearly established that a cost premium for responsiveness may be justified for profitable time‐sensitive products, and that this cost premium may suffice to render production in a high‐cost environment competitive. Time‐insensitive products considered in isolation seldom justify a cost premium, leading many decision makers to conclude that their production does not belong in a high‐cost environment. This leads to a manufacturing‐location decision in which profitable and time‐sensitive products are produced in a high‐cost environment and time‐insensitive products are transferred to a low‐cost environment. Responsiveness, however, requires a capacity buffer that provides the option to meet a demand peak for a profitable, time‐sensitive product. Leftover capacity can then be ideally deployed to manufacture time‐insensitive products to stock. We propose that the cost of the capacity buffer be considered as an option cost and assigned to the time‐sensitive product: “option‐based costing”. We then demonstrate use of demand volatility to create a portfolio of products that are time sensitive and insensitive to generate profit and increase competitiveness. Option‐based costing combined with a volatility portfolio reveals opportunities to produce competitively in high‐cost environments that have typically been considered unfeasible.
Echocardiography of coarctation of the aorta, aortic arch hypoplasia, and arch interruption: strategies for evaluation of the aortic arch
Authors: Goudar Suma P. , Shah Sanket S. , Shirali Girish S.
Published: February 2017

Aim

Echocardiography is the modality of choice for the diagnosis and serial follow-up of aortic arch pathology. In this article, we review the types of obstruction of the aortic arch, various classification schemes of coarctation of the aorta and interrupted aortic arch, methodology for optimal echocardiographic imaging of the aortic arch, and key echocardiographic measurements for accurate diagnosis of obstruction and hypoplasia of the aortic arch. Finally, we will discuss the limitations of echocardiography in optimal imaging of the aortic arch and the use of other non-invasive imaging modalities such as CT or MRI to provide additional information in these cases.

Background

Coarctation of the aorta is the more common lesion of the two, with an estimated incidence of four in every 10,000 live births in the United States of America. Interrupted aortic arch is rarer, with an incidence of 19 per one million live births.1 There is a spectrum of pathology of obstruction of the aortic arch, ranging from coarctation of the aorta with and without hypoplasia of the arch to interrupted aortic arch. Both these lesions are frequently encountered in congenital cardiology practice, and will be discussed in the remainder of this article. Obstruction of the aortic arch in the setting of hypoplastic left heart structures or atresia of the aortic valve is beyond the scope of this review and will not be discussed further.
The use of a three-dimensional print model of an aortic arch to plan a complex percutaneous intervention in a patient with coarctation of the aorta
Authors: Ghisiawan Nalini , Herbert Carrie E. , Zussman Matthew , Verigan Adam , Stapleton Gary E.
Published: February 2017

Recently, three-dimensional printing of heart models is being used to plan percutaneous and surgical interventions in patients with CHD. We describe a case where we used a three-dimensional print model to plan a complex percutaneous intervention in a patient with coarctation of the aorta.
Oral Function Improves Interfacial Integrity and Sealing Ability Between Conventional Glass Ionomer Cements and Dentin
Authors: Toledano Manuel , Osorio Raquel , Cabello Inmaculada , Osorio Estrella , Toledano-Osorio Manuel , Aguilera Fátima S.
Published: February 2017

The aim of this study was to investigate if load cycling affects interfacial integrity of glass ionomer cements bonded to sound- or caries-affected dentin. A conventional glass ionomer, Ketac Bond, and a resin-modified glass ionomer (Vitrebond Plus), were applied to dentin. Half of the specimens were load cycled. The interfaces were submitted to dye-assisted confocal microscopy evaluation. The unloaded specimens of sound and carious dentin were deficiently hybridized when Ketac Bond was used. Ketac Bond samples showed an absorption layer and an adhesive layer that were scarcely affected by fluorescein penetration (nanoleakage), in sound dentin. Nevertheless, a higher degree of micropermeability was found in carious dentin. In Ketac Bond specimens, load cycling improves the sealing capability and remineralization at the cement–dentin interface as porosity and nanoleakage was reduced. In contrast, samples treated with Vitrebond Plus exhibited a Rhodamine B-labeled absorption layer with scarce nanoleakage in both sound and carious unloaded dentin. The adhesive layer was affected by dye sorption throughout the porous cement–dentin interface. Samples treated with Vitrebond Plus had significant increases in nanoleakage and cement–dye sorption after load cycling. Within the limitations of an in vitro study, it is expected that conventional glass ionomers will provide major clinical efficacy when applied to carious-affected or sound dentin.
Excitation Dependent Phosphorous Property and New Model of the Structured Green Luminescence in ZnO
Authors: Ye Honggang , Su Zhicheng , Tang Fei , Wang Mingzheng , Chen Guangde , Wang Jian , Xu Shijie
Published: February 2017

The copper induced green luminescence (GL) with two sets of fine structures in ZnO crystal has been found for several decades (i.e., R. Dingle, Phys. Rev. Lett. 23, 579 (1969)), but the physical origin of the doublet still remains as an open question up to now. In this paper, we provide new insight into the mechanism of the structured GL band in terms of new experimental findings and theoretical calculations. It is found, for the first time, that the GL signal exhibits persistent afterglow for tens of minutes after the switch-off of below-band-gap excitation light but it cannot occur under above-band-gap excitation. Such a phosphorous property may be interpreted as de-trapping and feeding of electrons from a shallow trapping level via the conduction band to the Cu-related luminescence centers where the Cu3+ ion is proposed to work as the final state of the GL emission. From first-principles calculation, such a Cu3+ ion in wurtzite ZnO prefers a high spin 3d8 state with two non-degenerated half-filled orbitals due to the Jahn-Teller effect, probably leading to the double structures in photoluminescence spectrum. Therefore, this model gives a comprehensively new understanding on the mechanism of the structured GL band in ZnO.
Rapid detection of functional gene polymorphisms of TLRs and IL-17 using high resolution melting analysis
Authors: Teräsjärvi Johanna , Hakanen Antti , Korppi Matti , Nuolivirta Kirsi , Gröndahl-Yli-Hannuksela Kirsi , Mertsola Jussi , Peltola Ville , He Qiushui
Published: February 2017

Genetic variations in toll-like receptors (TLRs) and IL-17A have been widely connected to different diseases. Associations between susceptibility and resistance to different infections and single nucleotide polymorphisms (SNPs) in TLR1 to TLR4 and IL17A have been found. In this study, we aimed to develop a rapid and high throughput method to detect functional SNPs of above mentioned proteins. The following most studied and clinically important SNPs: TLR1 (rs5743618), TLR2 (rs5743708), TLR3 (rs3775291), TLR4 (rs4986790) and IL17 (rs2275913) were tested. High resolution melting analysis (HRMA) based on real-time PCR combined with melting analysis of a saturating double stranded-DNA binding dye was developed and used. The obtained results were compared to the “standard” sequencing method. A total of 113 DNA samples with known genotypes were included. The HRMA method correctly identified all genotypes of these five SNPs. Co-efficient values of variation of intra- and inter-run precision repeatability ranged from 0.04 to 0.23%. The determined limit of qualification for testing samples was from 0.5 to 8.0 ng/μl. The identical genotyping result was obtained from the same sample with these concentrations. Compared to “standard” sequencing methods HRMA is cost-effective, rapid and simple. All the five SNPs can be analyzed separately or in combination.
Multimodal optical analysis discriminates freshly extracted human sample of gliomas, metastases and meningiomas from their appropriate controls
Authors: Zanello Marc , Poulon Fanny , Pallud Johan , Varlet Pascale , Hamzeh H. , Abi Lahoud Georges , Andreiuolo Felipe , Ibrahim Ali , Pages Mélanie , Chretien Fabrice , Di Rocco Federico , Dezamis Edouard , Nataf François , Turak Baris , Devaux Bertrand , Abi Haidar Darine
Published: February 2017

Delineating tumor margins as accurately as possible is of primordial importance in surgical oncology: extent of resection is associated with survival but respect of healthy surrounding tissue is necessary for preserved quality of life. The real-time analysis of the endogeneous fluorescence signal of brain tissues is a promising tool for defining margins of brain tumors. The present study aims to demonstrate the feasibility of multimodal optical analysis to discriminate fresh samples of gliomas, metastases and meningiomas from their appropriate controls. Tumor samples were studied on an optical fibered endoscope using spectral and fluorescence lifetime analysis and then on a multimodal set-up for acquiring spectral, one and two-photon fluorescence images, second harmonic generation signals and two-photon fluorescence lifetime datasets. The obtained data allowed us to differentiate healthy samples from tumor samples. These results confirmed the possible clinical relevance of this real-time multimodal optical analysis. This technique can be easily applied to neurosurgical procedures for a better delineation of surgical margins.
The Conductive Silver Nanowires Fabricated by Two-beam Laser Direct Writing on the Flexible Sheet
Authors: He Gui-Cang , Zheng Mei-Ling , Dong Xian-Zi , Jin Feng , Liu Jie , Duan Xuan-Ming , Zhao Zhen-Sheng
Published: February 2017

Flexible electrically conductive nanowires are now a key component in the fields of flexible devices. The achievement of metal nanowire with good flexibility, conductivity, compact and smooth morphology is recognized as one critical milestone for the flexible devices. In this study, a two-beam laser direct writing system is designed to fabricate AgNW on PET sheet. The minimum width of the AgNW fabricated by this method is 187 ± 34 nm with the height of 84 ± 4 nm. We have investigated the electrical resistance under different voltages and the applicable voltage per meter range is determined to be less than 7.5 × 103 V/m for the fabricated AgNW. The flexibility of the AgNW is very excellent, since the resistance only increases 6.63% even after the stretched bending of 2000 times at such a small bending radius of 1.0 mm. The proposed two–beam laser direct writing is an efficient method to fabricate AgNW on the flexible sheet, which could be applied in flexible micro/nano devices.
Mitochondrial genome diversity in dagger and needle nematodes (Nematoda: Longidoridae)
Authors: Palomares-Rius J. E. , Cantalapiedra-Navarrete C. , Archidona-Yuste A. , Blok V. C. , Castillo P.
Published: February 2017

Dagger and needle nematodes included in the family Longidoridae (viz. Longidorus, Paralongidorus, and Xiphinema) are highly polyphagous plant-parasitic nematodes in wild and cultivated plants and some of them are plant-virus vectors (nepovirus). The mitochondrial (mt) genomes of the dagger and needle nematodes, Xiphinema rivesi, Xiphinema pachtaicum, Longidorus vineacola and Paralongidorus litoralis were sequenced in this study. The four circular mt genomes have an estimated size of 12.6, 12.5, 13.5 and 12.7 kb, respectively. Up to date, the mt genome of X. pachtaicum is the smallest genome found in Nematoda. The four mt genomes contain 12 protein-coding genes (viz. cox1-3, nad1-6, nad4L, atp6 and cob) and two ribosomal RNA genes (rrnL and rrnS), but the atp8 gene was not detected. These mt genomes showed a gene arrangement very different within the Longidoridae species sequenced, with the exception of very closely related species (X. americanum and X. rivesi). The sizes of non-coding regions in the Longidoridae nematodes were very small and were present in a few places in the mt genome. Phylogenetic analysis of all coding genes showed a closer relationship between Longidorus and Paralongidorus and different phylogenetic possibilities for the three Xiphinema species.
Association of Genomic Instability with HbA1c levels and Medication in Diabetic Patients
Authors: Grindel Annemarie , Brath Helmut , Nersesyan Armen , Knasmueller Siegfried , Wagner Karl-Heinz
Published: February 2017

Diabetes Mellitus type 2 (DM2) is associated with increased cancer risk. Instability of the genetic material plays a key role in the aetiology of human cancer. This study aimed to analyse genomic instability with the micronucleus cytome assay in exfoliated buccal cells depending on glycated haemoglobin (HbA1c) levels and medication in 146 female DM2 patients. The occurrence of micronuclei was significantly increased in DM2 patients compared to healthy controls. Furthermore, it was doubled in DM2 patients with HbA1c > 7.5% compared to subjects with HbA1c ≤ 7.5%. Positive correlations were found between micronuclei frequencies and HbA1c as well as fasting plasma glucose. Patients under insulin treatment showed a two-fold increase in micronuclei frequencies compared to subjects under first-line medication (no drugs or monotherapy with non-insulin medication). However, after separation of HbA1c (cut-off 7.5%) only patients with severe DM2 characterised by high HbA1c and insulin treatment showed higher micronuclei frequencies but not patients with insulin treatment and low HbA1c. We demonstrated that the severity of DM2 accompanied by elevated micronuclei frequencies predict a possible enhanced cancer risk among female DM2 patients. Therapy, therefore, should focus on a strict HbA1c control and personalised medical treatments.
High Performance MgO-barrier Magnetic Tunnel Junctions for Flexible and Wearable Spintronic Applications
Authors: Chen Jun-Yang , Lau Yong-Chang , Coey J. M. D. , Li Mo , Wang Jian-Ping
Published: February 2017

The magnetic tunnel junction (MTJ) using MgO barrier is one of most important building blocks for spintronic devices and has been widely utilized as miniaturized magentic sensors. It could play an important role in wearable medical devices if they can be fabricated on flexible substrates. The required stringent fabrication processes to obtain high quality MgO-barrier MTJs, however, limit its integration with flexible electronics devices. In this work, we have developed a method to fabricate high-performance MgO-barrier MTJs directly onto ultrathin flexible silicon membrane with a thickness of 14 μm and then transfer-and-bond to plastic substrates. Remarkably, such flexible MTJs are fully functional, exhibiting a TMR ratio as high as 190% under bending radii as small as 5 mm. The devices‘ robustness is manifested by its retained excellent performance and unaltered TMR ratio after over 1000 bending cycles. The demonstrated flexible MgO-barrier MTJs opens the door to integrating high-performance spintronic devices in flexible and wearable electronics devices for a plethora of biomedical sensing applications.
Tuning the band gap and polarization of BaSnO3/SrSnO3 superlattices for photovoltaic applications
Authors: Zhang Yajun , Sahoo M. P. K. , Wang Jie
Published: February 2017

Tuning the band gap and polarization of BaSnO3/SrSnO3 superlattices through strain engineering for solar cell applications.
The dehydrogenation mechanism during the incubation period in nanocrystalline MgH2
Authors: Shantilal Gangrade Apurva , Aditya Varma Akhil , Kishor Gor Nikhil , Shriniwasan Sweta , Tatiparti Sankara Sarma V.
Published: February 2017

The dehydrogenation mechanism during the incubation period in nanocrystalline MgH2 (low α: converted metal fraction and dα/dt) and the reasons for the occurrence of the incubation period at 320, 350, and 400 °C were investigated.
Synthesis of (E)-β-iodo vinylsulfones via iodine-promoted iodosulfonylation of alkynes with sodium sulfinates in an aqueous medium at room temperature
Authors: Sun Yadong , Abdukader Ablimit , Lu Dong , Zhang Haiyan , Liu Chenjiang
Published: February 2017

An efficient and facile molecular iodine-promoted method for the synthesis of (E)-β-iodo vinylsulfones with high regio- and stereoselectivity using water as the solvent at room temperature is presented.
Eight at one stroke – a synthetic tetra-disulfide peptide epitope
Authors: Schrimpf Andreas , Linne Uwe , Geyer Armin
Published: February 2017

A tetra-disulfide peptide dimer, representing an antiparallel hinge, is synthesised without the need for orthogonal cysteine protecting groups.
Modeling excitation energy transfer in multi-BODIPY architectures
Authors: Azarias Cloé , Russo Roberto , Cupellini Lorenzo , Mennucci Benedetta , Jacquemin Denis
Published: February 2017

The excitation energy transfer (EET) allowing energy concentration in several multi-BODIPY architectures has been investigated with an ab initio approach. Systems with improved EET have been designed.
Gamma Knife Stereotactic Radiosurgery for Grade 2 Meningiomas
Authors: Refaat Tamer , Gentile Michelle , Sachdev Sean , Dalal Prarthana , Butala Anish , Gutiontov Stanley , Helenowksi Irene , Lee Plato , Sathiaseelan Vythialinga , Bloch Orin , Chandler James , Kalapurakal John
Published: February 2017

Purpose This study aims to report long-term clinical outcomes after Gamma Knife radiosurgery (GKRS) for intracranial grade 2 meningiomas.

Methods In this Institutional Review Board approved study, we reviewed records of all patients with grade 2 meningiomas treated with GKRS between 1998 and 2014.

Results A total of 97 postoperative histopathologically confirmed grade 2 meningiomas in 75 patients were treated and are included in this study. After a mean follow-up of 41 months, 28 meningiomas had local recurrence (29.79%). Median time to local recurrence was 89 months (mean: 69, range: 47–168). The 3- and 5-year actuarial local control (LC) rates were 68.9 and 55.7%, respectively. The 3- and 5-year overall survival rates were 88.6 and 81.1%, respectively. There was a trend toward worse LC with tumors treated with radiation doses ≤ 13 versus > 13 Gy. There was no radiation necrosis or second malignant tumors noted in our series.

Conclusion This report, one of the largest GKRS series for grade 2 meningiomas, demonstrates that GKRS is a safe and effective treatment modality for patients with grade 2 meningiomas with durable tumor control and minimal toxicity. Adjuvant GKRS could be considered as a reasonable treatment approach for patients with grade 2 meningiomas.
Die Brille als Bewertungsfaktor im Gutachten
Authors: Burggraf M.
Published: February 2017

Die optische Korrektur ist im Gutachten ein eigener Faktor. Es wird skizziert, wie er in den verschiedenen Rechtsgebieten unterschiedlich zu beachten ist.
Sample environment for neutron scattering measurements of internal stresses in engineering materials in the temperature range of 6 K to 300 K
Authors: Kirichek O. , Timms J. D. , Kelleher J. F. , Down R. B. E. , Offer C. D. , Kabra S. , Zhang S. Y.
Published: February 2017

Internal stresses in materials have a considerable effect on material properties including strength, fracture toughness, and fatigue resistance. The ENGIN-X beamline is an engineering science facility at ISIS optimized for the measurement of strain and stress using the atomic lattice planes as a strain gauge. Nowadays, the rapidly rising interest in the mechanical properties of engineering materials at low temperatures has been stimulated by the dynamic development of the cryogenic industry and the advanced applications of the superconductor technology. Here we present the design and discuss the test results of a new cryogenic sample environment system for neutron scattering measurements of internal stresses in engineering materials under a load of up to 100 kN and in the temperature range of 6 K to 300 K. Complete cooling of the system starting from the room temperature down to the base temperature takes around 90 min. Understanding of internal stresses in engineering materials at cryogenic temperatures is vital for the modelling and designing of cutting-edge superconducting magnets and other superconductor based applications.
In situ electrical resistivity measurements of vanadium thin films performed in vacuum during different annealing cycles
Authors: Pedrosa Paulo , Cote Jean-Marc , Martin Nicolas , Arab Pour Yazdi Mohammad , Billard Alain
Published: February 2017

The present study describes a sputtering and in situ vacuum electrical resistivity setup that allows a more efficient sputtering-oxidation coupling process for the fabrication of oxide compounds like vanadium dioxide, VO2. After the sputtering deposition of pure V thin films, the proposed setup enables the sample holder to be transferred from the sputtering to the in situ annealing + resistivity chamber without venting the whole system. The thermal oxidation of the V films was studied by implementing two different temperature cycles up to 550 °C, both in air (using a different resistivity setup) and vacuum conditions. Main results show that the proposed system is able to accurately follow the different temperature setpoints, presenting clean and low-noise resistivity curves. Furthermore, it is possible to identify the formation of different vanadium oxide phases in air, taking into account the distinct temperature cycles used. The metallic-like electrical properties of the annealed coatings are maintained in vacuum whereas those heated in air produce a vanadium oxide phase mixture.
A paradigm for modeling and computation of gas dynamics
Authors: Xu Kun , Liu Chang
Published: February 2017

In the continuum flow regime, the Navier-Stokes (NS) equations are usually used for the description of gas dynamics. On the other hand, the Boltzmann equation is applied for the rarefied flow. These two equations are based on distinguishable modeling scales for flow physics. Fortunately, due to the scale separation, i.e., the hydrodynamic and kinetic ones, both the Navier-Stokes equations and the Boltzmann equation are applicable in their respective domains. However, in real science and engineering applications, they may not have such a distinctive scale separation. For example, around a hypersonic flying vehicle, the flow physics at different regions may correspond to different regimes, where the local Knudsen number can be changed significantly in several orders of magnitude. With a variation of flow physics, theoretically a continuous governing equation from the kinetic Boltzmann modeling to the hydrodynamic Navier-Stokes dynamics should be used for its efficient description. However, due to the difficulties of a direct modeling of flow physics in the scale between the kinetic and hydrodynamic ones, there is basically no reliable theory or valid governing equations to cover the whole transition regime, except resolving flow physics always down to the mean free path scale, such as the direct Boltzmann solver and the Direct Simulation Monte Carlo (DSMC) method. In fact, it is an unresolved problem about the exact scale for the validity of the NS equations, especially in the small Reynolds number cases. The computational fluid dynamics (CFD) is usually based on the numerical solution of partial differential equations (PDEs), and it targets on the recovering of the exact solution of the PDEs as mesh size and time step converging to zero. This methodology can be hardly applied to solve the multiple scale problem efficiently because there is no such a complete PDE for flow physics through a continuous variation of scales. For the non-equilibrium flow study, the direct modeling methods, such as DSMC, particle in cell, and smooth particle hydrodynamics, play a dominant role to incorporate the flow physics into the algorithm construction directly. It is fully legitimate to combine the modeling and computation together without going through the process of constructing PDEs. In other words, the CFD research is not only to obtain the numerical solution of governing equations but to model flow dynamics as well. This methodology leads to the unified gas-kinetic scheme (UGKS) for flow simulation in all flow regimes. Based on UGKS, the boundary for the validation of the Navier-Stokes equations can be quantitatively evaluated. The combination of modeling and computation provides a paradigm for the description of multiscale transport process.
Solutions for a class of quasilinear Schrödinger equations with critical Sobolev exponents
Authors: Li Zhouxin , Zhang Yimin
Published: February 2017

In this paper, we study a class of quasilinear Schrödinger equations involving a critical exponent which arises in plasma physics. By using the change of variable and variational approaches combining the concentration-compactness principle, the existence of a positive solution which has a local maximum point and decays exponentially is obtained.
Effects of ion motion on linear Landau damping
Authors: Xu Hui , Sheng Zheng-Ming , Kong Xiang-Mu , Su Fu-Fang
Published: February 2017

The effects of ion motion on Landau damping has been studied by the use of one-dimensional Vlasov-Poisson simulation. It is shown that the ion motion may significantly change the development of the linear Landau damping. When the ion mass is multiple of proton mass, its motion will halt the linear Landau damping at some time due to the excitation of ion acoustic waves. The latter will dominate the system evolution at the later stage and hold a considerable fraction of the total energy in the system. With very small ion mass, such as in electron-positron plasma, the ion motion can suppress the linear Landau damping very quickly. When the initial field amplitude is relatively high such as with the density perturbation amplitude δn/n0 > 0.1, the effect of ion motion on Landau damping is found to be weak or even ignorable.
Analysis and application of neuronal network controllability and observability
Authors: Su Fei , Wang Jiang , Li Huiyan , Deng Bin , Yu Haitao , Liu Chen
Published: February 2017

Controllability and observability analyses are important prerequisite for designing suitable neural control strategy, which can help lower the efforts required to control and observe the system dynamics. First, 3-neuron motifs including the excitatory motif, the inhibitory motif, and the mixed motif are constructed to investigate the effects of single neuron and synaptic dynamics on network controllability (observability). Simulation results demonstrate that for networks with the same topological structure, the controllability (observability) of the node always changes if the properties of neurons and synaptic coupling strengths vary. Besides, the inhibitory networks are more controllable (observable) than the excitatory networks when the coupling strengths are the same. Then, the numerically determined controllability results of 3-neuron excitatory motifs are generalized to the desynchronization control of the modular motif network. The control energy and neuronal synchrony measure indexes are used to quantify the controllability of each node in the modular network. The best driver node obtained in this way is the same as the deduced one from motif analysis.
A generalization of random matrix theory and its application to statistical physics
Authors: Wang Duan , Zhang Xin , Horvatic Davor , Podobnik Boris , Eugene Stanley H.
Published: February 2017

To study the statistical structure of crosscorrelations in empirical data, we generalize random matrix theory and propose a new method of cross-correlation analysis, known as autoregressive random matrix theory (ARRMT). ARRMT takes into account the influence of auto-correlations in the study of cross-correlations in multiple time series. We first analytically and numerically determine how auto-correlations affect the eigenvalue distribution of the correlation matrix. Then we introduce ARRMT with a detailed procedure of how to implement the method. Finally, we illustrate the method using two examples taken from inflation rates for air pressure data for 95 US cities.
Gigahertz scanning acoustic microscopy analysis of voids in Cu-Sn micro-connects
Authors: Ross G. , Vuorinen V. , Petzold M. , Paulasto-Kröckel M. , Brand S.
Published: February 2017

Gigahertz scanning acoustic microscopy (GHz-SAM) is applied to the characterization of bulk voids in the Cu-Sn material system, often used in micro-connects. An increased demand for the development of miniaturized interconnect technologies, such as micro-connects, means that fast characterization methods are required for the assessment and detection of reliability impacting defects. This study attempts to formulate an analytical technique aimed at detecting micro-structural defects in Cu-Sn micro-connects, such as micro-bumps for 1st level interconnects and solid-liquid interdiffusion bonds for nano- and microelectromechanical systems. To study the potential of the analytical method, a specific electroplating chemistry was used that increases the probability of defect formation in the electroplated Cu film. The chemistry is known under certain electroplating overpotentials to promote hydrogen bubble induced voids within the Cu. The samples containing voids were inspected by GHz-SAM with a highly focused acoustic lens operating at 1.12 GHz. To validate the results, GHz-SAM micrographs were compared with focused ion beam prepared cross-sections of the selected samples. Advances in acoustic transducer technology operating in the GHz frequency band allow for micron sized defect examination of materials with enhanced lateral resolution and sub-surface sensitivity.
Reversible transition between coherently strained BiFeO3 and the metastable pseudotetragonal phase on (LaAlO3)0.3(Sr2AlTaO6)0.7 (001)
Authors: Fu Z. , Yin Z. G. , Zhang X. W. , Chen N. F. , Zhao Y. J. , Bai Y. M. , Zhao D. Y. , Zhang H. F. , Yuan Y. D. , Chen Y. N. , Wu J. L. , You J. B.
Published: February 2017

Coherently strained BiFeO3 epitaxial films deposited on (001)-oriented (LaAlO3)0.3(Sr2AlTaO6)0.7 have a tetragonal crystal form, a stress-distorted version of the rhombohedral phase. A conversion from coherent BiFeO3 to a new, tilted pseudotetragonal phase with the c/a ratio exceeding 1.2 is observed beyond the critical thickness of 60 nm. X-ray reciprocal space maps display that this highly elongated metastable structure is monoclinically distorted by ∼0.2° and exhibits an out-of-plane tilt of ∼3°. These observations are at odds with traditional understandings that a coherent epilayer should turn into its parent structure upon increasing the thickness, providing a new insight into the strain relaxation mechanism of epitaxial films. We show that in the heating and cooling cycles, the transition between these two phases is completely reversible and is associated with the alleviation of thermal stress. Our results reveal that the coherent BiFeO3 epilayer with tetragonal symmetry stabilized by moderate compressive strain behaves as a structural bridge that links the thermally stable rhombohedral phase and the metastable tetragonal-like phase with a giant axial ratio. Moreover, the finding of a BiFeO3 phase mixture in our study extends the threshold in-plane strain of the stress-driven morphotropic phase boundary to a value as low as −2.3%.
Photoacoustic eigen-spectrum from light-absorbing microspheres and its application in noncontact elasticity evaluation
Authors: Gao Xiaoxiang , Tao Chao , Liu Xiaojun , Wang Xueding
Published: February 2017

Noncontact evaluation of elastic properties of a microstructure is still a challenge in turbid media. In this Letter, we present the observation of a phenomenon—the photoacoustic eigen-spectrum from light-absorbing objects. Analysis and experiments demonstrate that the eigen-vibration information of a microstructure is imprinted in its photoacoustic coda waves after it is exposed to a laser pulse illumination. The spectral lines in the time-frequency map of photoacoustic coda waves correspond to the eigen-frequencies of the light-absorber. This phenomenon provides a physical basis for noncontact evaluation of elastic properties of a microstructure in turbid media. Elastic parameters can be accurately inversed from the measured photoacoustic eigen-spectrum.
Effect of the spatial current dynamics on radiative characteristics of high-power lasers-thyristors based on AlGaAs/GaAs heterostructures
Authors: Slipchenko S. O. , Podoskin A. A. , Soboleva O. S. , Pikhtin N. A. , Bagaev T. A. , Ladugin M. A. , Marmalyuk A. A. , Simakov V. A. , Tarasov I. S.
Published: February 2017

The effect of a local current turn-on in the heterostructure plane has been observed for low-voltage lasers-thyristors. It was shown that the spatial dynamics of the current-turn-on region is determined by the blocking voltage and the control current amplitude. For the first mode (blocking voltages up to 15 V), the current nonuniformity in the heterostructure plane is determined by the flux distribution of the spontaneous emission from the active region in the laser part to the side of the p-base of the phototransistor part of the heterostructure. The transition to the second mode (blocking voltages exceeding 15 V) is due to the sharp rise in the generation rate of excess carriers in the p-base of the phototransistor part of the heterostructure. In this case, the size of the region in which the original current turn-on occurs decreases to 70 μm. It was found that the rate at which the current-turn-on region expands depends on the working conditions of the laser part of the laser-thyristor and is 50 and 20 μm/ns for the spontaneous generation and lasing modes, respectively. It was also found that the spatial dynamics of the current determines the spatial dynamics of the laser light turn-on in the lateral waveguide and the emission efficiency in generation of short (<10 ns) laser pulses. It was demonstrated that, at low control currents, the main contribution to the decrease in the emission efficiency is made by the residual optical loss in the turned-off part of the laser-thyristor. At higher amplitudes of the control current, the emission efficiency grows due to the decrease in the residual loss in the turned-off part of the laser-thyristor, which made it possible to raise the peak power to 47 W for 100-ns laser pulses.
Piezoelectric d36 in-plane shear-mode of lead-free BZT-BCT single crystals for torsion actuation
Authors: Berik P. , Chang W.-Y. , Jiang X.
Published: February 2017

We report the study of piezoelectric direct torsion actuation mechanism using lead-free piezoelectric d36 in-plane shear-mode BZT-BCT single crystals. The generated angle of twist of the piezoelectric torsion actuator was obtained from the transverse deflection measurement using a laser vibrometer. The bi-morph torsional actuator, consisting of two lead-free piezoelectric BZT-BCT in-plane shear-mode single crystals with a giant piezoelectric d36 shear strain coefficient of 1590 pC/N, provided a rate of twist of 34.12 mm/m under a quasi-static 15 V drive. The experimental benchmark was further modelled and verified by the ANSYS software using three dimensional (3D) piezoelectric finite elements. The experimental results revealed that lead-free piezoelectric BZT-BCT d36-mode single crystal is a superior candidate for piezoelectric torsion actuation. This lead-free piezoelectric BZT-BCT d36-mode torsion actuator can be effectively applied in torsional deformation control by taking into account the environmental considerations.
Voltage-driven magnetization control in topological insulator/magnetic insulator heterostructures
Authors: Flatté Michael E.
Published: February 2017

A major barrier to the development of spin-based electronics is the transition from current-driven spin torque, or magnetic-field-driven magnetization reversal, to a more scalable voltage-driven magnetization reversal. To achieve this, multiferroic materials appear attractive, however the effects in current materials occur at very large voltages or at low temperatures. Here the potential of a new class of hybrid multiferroic materials is described, consisting of a topological insulator adjacent to a magnetic insulator, for which an applied electric field reorients the magnetization. As these materials lack conducting states at the chemical potential in their bulk, no dissipative charge currents flow in the bulk. Surface states at the interface, if present, produce effects similar to surface recombination currents in bipolar devices, but can be passivated using magnetic doping. Even without conducting states at the chemical potential, for a topological insulator there is a finite spin Hall conductivity provided by filled bands below the chemical potential. Spin accumulation at the interface with the magnetic insulator provides a torque on the magnetization. Properly timed voltage pulses can thus reorient the magnetic moment with only the flow of charge current required in the leads to establish the voltage. If the topological insulator is sufficiently thick the resulting low capacitance requires little charge current.
Supercooled water survives in no-man’s-land
Authors: Smart Ashley G.
Published: February 2017

A “stop-motion” crystallization experiment laid bare the liquid’s behavior in a temperature range that was once considered inaccessible.
In referees we trust?
Authors: Baldwin Melinda
Published: February 2017

The imprimatur bestowed by peer review has a history that is both shorter and more complex than many scientists realize.
Improving acoustic estimates of krill: experience from repeat sampling of northern krill (Meganyctiphanes norvegica) in Gullmarsfjord, Sweden
Authors: Everson Inigo , Tarling Geraint A. , Bergström Bo
Published: February 2017

Everson, I., Tarling, G. A., and Bergström, B. 2007. Improving acoustic estimates of krill: experience from repeat sampling of northern krill (Meganyctiphanes norvegica) in Gullmarsfjord, Sweden – ICES Journal of Marine Research, 64, 39–48. A series of eight replicated acoustic surveys, four by day and four by night, was undertaken in Gullmarsfjord on the Swedish west coast during two 24-h periods on 8 and 10 September 2003, using a calibrated echosounder operating at 120 and 38 kHz. The difference in signal strength (ΔSv) was used to distinguish northern krill (Meganyctiphanes norvegica) from other acoustic scatterers. The approach is concluded to be very effective, but it can be improved greatly by applying the following series of simple extensions to current protocols: first, set a very low threshold on both frequencies to minimize sampling bias; second, undertake tests to confirm that the data extracted from each acoustic frequency apply to the same scatterers; third, ensure that the range of ΔSv is not greater than the TSrange at either frequency; and finally, when abundance estimation is the primary aim, arrange for sampling at the time of day and using the acoustic frequency that together provide the least variance.
Confirmation that abscisic acid accumulation is required for maize primary root elongation at low water potentials
Authors: Sharp Robert E. , Wu Yajun , Voetberg Gary S. , Saab Imad N. , LeNoble Mary E.
Published: February 2017

Previous work showed that primary root elongation in maize (Zeamays L.) seedlings at low water potentials was severely inhibited when accumulation of abscisic acid (ABA) was decreased using either fluridone or the vp5 mutant to inhibit carotenoid (and ABA) biosynthesis. The objective of this study was to confirm that the inhibition of root elongation resulting from these treatments was indeed attributable to the decrease in ABA levels. Seedlings were transplanted after germination to vermiculite at water potentials of −1.6 or − 0.3 MPa. ABA was mixed at various concentrations with the vermiculite to test whether the effects of fluridone and the vp5 mutation on root elongation could be overcome. In both treatments, restoration of ABA levels in the root apical 10 mm, which encompassed the elongation zone, resulted in recovery of root elongation rate at both −1.6 MPa and −0.3 MPa. Analysis of the spatial distribution of elongation rate showed that the recovery of overall root elongation resulted from restoration of the profile of elongation, and did not involve over-promotion of local elongation rate at any position. The recovery of root elongation was shown to be independent of effects of ABA status on shoot growth. When ABA was applied at high water potential, such that levels of ABA in the root tip reached those associated with maintenance of elongation at low water potentials, root elongation was inhibited. Thus, the response of root elongation to bulk tissue ABA content varied with the tissue water status. The results confirm that accumulation of ABA is required for the maintenance of maize primary root elongation at low water potentials.
Natural Radionuclides in Ground Water in Finland
Authors: Salonen L.
Published: February 2017

A nationwide survey of the natural radioactivity in drinking water was conducted in Finland throughout the 1970s and has continued in the 1980s with the emphasis on drinking water originating from drilled wells, which may be rich in natural radionuclides (mean 222Rn 1020 Bq.l-1, maximum 77,000 Bq.l-1). Between 1981 and 1987, 3000 ground water samples were analysed for 222Rn, some of them for gross alpha and beta, 226Ra, 210Pb, 210Po and U. In recent years the occurrence of 210Pb and 210Po in ground water has been studied. Preliminary results suggest that the contribution of 210Pb and 210Po to the total annual effective dose equivalent is higher than the contribution of 226Ra or U in that water.