bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrafast bulk carrier recombination transients in n-type and semi-insulating 4H-SiC crystals
Authors: Fang Yu , Wu Xingzhi , Yang Junyi , Chen Gaoyuan , Chen Yongqiang , Wu Quanying , Song Yinglin
Published: May 2018

Carrier recombination influences the performance of SiC-based optoelectronic devices, and carrier recombination via traps is one of the limiting factors of carrier lifetime. In this work, we utilized transient absorption spectroscopy with near-homogeneous carrier distribution to evaluate ultrafast bulk carrier recombination in conductive (n-type) nitrogen-doped and semi-insulating (SI) vanadium-doped 4H-SiC wafers. Compared to n-type 4H-SiC, a pronounced modulation of transient absorption was observed in SI 4H-SiC, resulting from an additional decay process subsequent to intraband recombination (2–3 ps) caused by carrier trapping of V3+/4+ deep acceptors. The carrier-trapping lifetime (∼16 ps) was three orders of magnitude faster than that via N-doping and/or inherent defects. With a simplified model and global analysis, the carrier recombination mechanisms and lifetimes in 4H-SiC were determined unambiguously.
Associative desorption of hydrogen isotopologues from copper surfaces: Characterization of two reaction mechanisms
Authors: Kaufmann Sven , Shuai Quan , Auerbach Daniel J. , Schwarzer Dirk , Wodtke Alec M.
Published: May 2018

We report quantum-state resolved measurements of angular and velocity distributions of the associative desorption of H2, HD, and D2 from Cu(111) and Cu(211) surfaces. The desorbing molecules have bimodal velocity distributions comprising a “fast” channel and a “slow” channel on both facets. The “fast channel” is promoted by both hydrogen incidence translational and vibrational energy, while the “slow channel” is promoted by vibrational energy but inhibited by translational energy. Using detailed balance, we determine state-specific reaction probabilities for dissociative adsorption and compare these to theoretical calculations. The results for the activation barrier for the “fast channel” on Cu(111) are in agreement with theory within “chemical accuracy” (1 kcal/mole). Results on the Cu(211) facet provide direct information on the effect of increasing step density, which is commonly believed to increase reactivity. Differences in reactivity on the (111) and (211) facets are subtle – quantum state specific reactivity on the (211) surface is characterized by a broader distribution of barrier heights whose average values are higher than for reaction on (111). We fully characterize the “slow channel,” which has not been found in theoretical calculations although it makes up a large fraction of the reactivity in these experiments.
Optical determination of charge transfer times from indoline dyes to ZnO in solid state dye-sensitized solar cells
Authors: Meyenburg I. , Hofeditz N. , Ruess R. , Rudolph M. , Schlettwein D. , Heimbrodt W.
Published: May 2018

We studied the electron transfer at the interface of organic-inorganic hybrids consisting of indoline derivatives (D149 and D131) on ZnO substrates using a new optical method. We revealed the electron transfer times from the excited dye, e.g. the excitons formed in the dye aggregates to the ZnO substrate by analyzing the photoluminescence transients of the excitons after femtosecond excitation and applying kinetic model calculations. We reveal the changes of the electron transfer times by applying electrical bias. Pushing the Fermi energy of the ZnO substrate towards the excited dye level the transfer time gets longer and eventually the electron transfer is suppressed. The level alignment between the excited dye state and the ZnO Fermi-level is estimated. The excited state of D131 is about 100 meV higher than the respective state of D149 compared to the ZnO conduction band. This leads to shorter electron transfer times and eventually to higher quantum efficiencies of the solar cells.
Lattice induced strong coupling and line narrowing of split resonances in metamaterials
Authors: Tan Thomas CaiWei , Srivastava Yogesh Kumar , Manjappa Manukumara , Plum Eric , Singh Ranjan
Published: May 2018

Strongly coupled metamaterial resonances typically undergo mode-splitting by which there is an exchange of energy between matter excitations and photons. Here, we report a strong coupling of the lattice mode with the structural eigen-resonances of an asymmetric split-ring metamaterial associated with mode-splitting and resonance line-narrowing that gives rise to high quality factor (Q-factor) resonances. We demonstrate selective control of the resonance strength, line-width, and Q-factor of individual split-ring modes by tailoring the coupling of the fundamental lattice mode to each of the hybridized resonances. A three-coupled-oscillator model shows lattice-mediated strong coupling in the form of an anti-crossing behavior between the hybridized metamaterial resonances. Such schemes of strong coupling between the lattice and the hybrid modes of the metamaterial unit cell offer an avenue to invoke lattice induced transparency, high-Q resonances and strong field confinement, which could find applications in designing slow light devices, ultrasensitive sensors, and multiband narrow filters.
Gyroaveraging operations using adaptive matrix operators
Authors: Dominski Julien , Ku Seung-Hoe , Chang Choong-Seock
Published: May 2018

A new adaptive scheme to be used in particle-in-cell codes for carrying out gyroaveraging operations with matrices is presented. This new scheme uses an intermediate velocity grid whose resolution is adapted to the local thermal Larmor radius. The charge density is computed by projecting marker weights in a field-line following manner while preserving the adiabatic magnetic moment μ. These choices permit to improve the accuracy of the gyroaveraging operations performed with matrices even when strong spatial variation of temperature and magnetic field is present. Accuracy of the scheme in different geometries from simple 2D slab geometry to realistic 3D toroidal equilibrium has been studied. A successful implementation in the gyrokinetic code XGC is presented in the delta-f limit.
Time-resolved photoelectron spectroscopy of adenosine and adenosine monophosphate photodeactivation dynamics in water microjets
Authors: Williams Holly L. , Erickson Blake A. , Neumark Daniel M.
Published: May 2018

The excited state relaxation dynamics of adenosine and adenosine monophosphate were studied at multiple excitation energies using femtosecond time-resolved photoelectron spectroscopy in a liquid water microjet. At pump energies of 4.69–4.97 eV, the lowest ππ* excited state, S1, was accessed and its decay dynamics were probed via ionization at 6.20 eV. By reversing the role of the pump and probe lasers, a higher-lying ππ* state was excited at 6.20 eV and its time-evolving photoelectron spectrum was monitored at probe energies of 4.69–4.97 eV. The S1 ππ* excited state was found to decay with a lifetime ranging from ∼210 to 250 fs in adenosine and ∼220 to 250 fs in adenosine monophosphate. This lifetime drops with increasing pump photon energy. Signal from the higher-lying ππ* excited state decayed on a time scale of ∼320 fs and was measureable only in adenosine monophosphate.
A theoretical investigation on Cu/Ag/Au bonding in XH2P⋯MY(X = H, CH3, F, CN, NO2; M = Cu, Ag, Au; Y = F, Cl, Br, I) complexes
Authors: Wang Zhaoxu , Liu Yi , Zheng Baishu , Zhou Fengxiang , Jiao Yinchun , Liu Yuan , Ding XunLei , Lu Tian
Published: May 2018

Intermolecular interaction of XH2P···MY (X = H, CH3, F, CN, NO2; M = Cu, Ag, Au; Y = F, Cl, Br, I) complexes was investigated by means of an ab initio method. The molecular interaction energies are in the order Ag < Cu < Au and increased with the decrease of RP···M. Interaction energies are strengthened when electron-donating substituents X connected to XH2P, while electron-withdrawing substituents produce the opposite effect. The strongest P···M bond was found in CH3H2P···AuF with −70.95 kcal/mol, while the weakest one was found in NO2H2P···AgI with −20.45 kcal/mol. The three-center/four-electron (3c/4e) resonance-type of P:-M-:Y hyperbond was recognized by the natural resonance theory and the natural bond orbital analysis. The competition of P:M–Y ↔ P–M:Y resonance structures mainly arises from hyperconjugation interactions; the bond order of bP–M and bM–Y is in line with the conservation of the idealized relationship bP–M + bM–Y ≈ 1. In all MF-containing complexes, P–M:F resonance accounted for a larger proportion which leads to the covalent characters for partial ionicity of MF. The interaction energies of these Cu/Ag/Au complexes are basically above the characteristic values of the halogen-bond complexes and close to the observed strong hydrogen bonds in ionic hydrogen-bonded species.
Communication: Diffusion constant in supercooled water as the Widom line is crossed in no man’s land
Authors: Ni Yicun , Hestand Nicholas J. , Skinner J. L.
Published: May 2018

According to the liquid-liquid critical point (LLCP) hypothesis, there are two distinct phases of supercooled liquid water, namely, high-density liquid and low-density liquid, separated by a coexistence line that terminates in an LLCP. If the LLCP is real, it is located within No Man’s Land (NML), the region of the metastable phase diagram that is difficult to access using conventional experimental techniques due to rapid homogeneous nucleation to the crystal. However, a recent ingenious experiment has enabled measurement of the diffusion constant deep inside NML. In the current communication, these recent measurements are compared, with good agreement, to the diffusion constant of E3B3 water, a classical water model that explicitly includes three-body interactions. The behavior of the diffusion constant as the system crosses the Widom line (the extension of the liquid-liquid coexistence line into the one-phase region) is analyzed to derive information about the presence and location of the LLCP. Calculations over a wide range of temperatures and pressures show that the new experimental measurements are consistent with an LLCP having a critical pressure of over 0.6 kbar.
Sasa-Satsuma hierarchy of integrable evolution equations
Authors: Bandelow U. , Ankiewicz A. , Amiranashvili Sh. , Akhmediev N.
Published: May 2018

We present the infinite hierarchy of Sasa-Satsuma evolution equations. The corresponding Lax pairs are given, thus proving its integrability. The lowest order member of this hierarchy is the nonlinear Schrödinger equation, while the next one is the Sasa-Satsuma equation that includes third-order terms. Up to sixth-order terms of the hierarchy are given in explicit form, while the provided recurrence relation allows one to explicitly write all higher-order terms. The whole hierarchy can be combined into a single general equation. Each term in this equation contains a real independent coefficient that provides the possibility of adapting the equation to practical needs. A few examples of exact solutions of this general equation with an infinite number of terms are also given explicitly.
A theoretical model for predicting the feature size printed by electrohydrodynamic jet printing
Authors: Qian Lei , Lan Hongbo , Zhang Guangming
Published: May 2018

This paper presents a theoretical model for predicting the micro-scale feature size of patterns printed by electrohydrodynamic jet printing. The feature size of printed patterns, including the diameter of discrete dots or the width of continuous lines, can be defined as a function of experimental parameters such as the voltage magnitude, pulse frequency, air pressure, stage speed, material viscosity, and contact angle, based on the assumptions of volume conservation and energy balance. The proposed theoretical model is validated against experimental results for various combinations of printing materials and substrates. Using the theoretical model, we can reasonably predict the feature size to guide the experimental optimization of electrohydrodynamic jet printing.
New Products
Authors: Mandelis Andreas
Published: May 2018

In order to supplement manufacturers’ information, this Department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials which supersede earlier data or suggest new research applications.
Using some results about the Lie evolution of differential operators to obtain the Fokker-Planck equation for non-Hamiltonian dynamical systems of interest
Authors: Bianucci Marco
Published: May 2018

Finding the generalized Fokker-Planck Equation (FPE) for the reduced probability density function of a subpart of a given complex system is a classical issue of statistical mechanics. Zwanzig projection perturbation approach to this issue leads to the trouble of resumming a series of commutators of differential operators that we show to correspond to solving the Lie evolution of first order differential operators along the unperturbed Liouvillian of the dynamical system of interest. In this paper, we develop in a systematic way the procedure to formally solve this problem. In particular, here we show which the basic assumptions are, concerning the dynamical system of interest, necessary for the Lie evolution to be a group on the space of first order differential operators, and we obtain the coefficients of the so-evolved operators. It is thus demonstrated that if the Liouvillian of the system of interest is not a first order differential operator, in general, the FPE structure breaks down and the master equation contains all the power of the partial derivatives, up to infinity. Therefore, this work shed some light on the trouble of the ubiquitous emergence of both thermodynamics from microscopic systems and regular regression laws at macroscopic scales. However these results are very general and can be applied also in other contexts that are non-Hamiltonian as, for example, geophysical fluid dynamics, where important events, like El Niño, can be considered as large time scale phenomena emerging from the observation of few ocean degrees of freedom of a more complex system, including the interaction with the atmosphere.
Variation in residual feed intake depends on feed on offer
Authors: Pitchford W. S. , Lines D. S. , Wilkes M. J.
Published: May 2018

Two small pen trials with cattle and sheep both clearly demonstrated that while there is significant variation in residual feed intake when on high energy supply, there is negligible variation when energy supply is limited. A review of literature demonstrated that this is also the case when energy supply is limited by heat or physiological state, such as peak lactation, and in multiple species. There is little evidence of variation in efficiency of maintenance requirements, growth or lactation. Nor is there strong evidence for large variation in digestibility within breeds, despite some differences between divergent breeds. Thus, the primary source of variation in residual feed intake must be in appetite and, in variable environments, it is possible that those with greater appetite are more resilient during times of feed shortage.
Emergence of serranid pigment abnormality syndrome (SPAS) in wire netting cod (Epinephelus quoyanus) from Heron Island on the southern Great Barrier Reef
Authors: Diggles B. K. , Ernst I. , Wesche S.
Published: May 2018

Coral reefs worldwide are under increasing stress from anthropogenic impacts, but there are relatively few reports of increased rates of disease in coral reef fish. Herein we report the emergence of abnormal skin lesions in wild-caught wire netting cod (Epinephelus quoyanus) near Heron Island in the southern Great Barrier Reef. The lesion involves conspicuous darkening and disorganisation of the brown ‘wire netting’ colouration pattern typical of this species, most commonly on the lower jaw, premaxilla and head, with occasional involvement of the flanks and dorsal fin in some fish. The lesion was not present during research conducted in the mid-1990s; however, since it was first recorded in 2012, the prevalence of grossly visible lesions has increased to 16.9% in 2017, with fish >340mm long most affected (prevalence 64.7%). These data suggest emergence of the lesion is a recent phenomenon and that causative factors may be age related. Abnormal pigmentation lesions have only been observed to affect E. quoyanus and coral trout (Plectropomus leopardus; since 2010). Given the species affected and the currently unknown aetiology of these lesions, we name the condition serranid pigment abnormality syndrome (SPAS). Further research is required to determine its geographic distribution, establish causation and describe the course of disease in E. quoyanus.
Growth of sedimentaryBathyarchaeotaon lignin as an energy source
Authors: Yu Tiantian , Wu Weichao , Liang Wenyue , Lever Mark Alexander , Hinrichs Kai-Uwe , Wang Fengping
Published: May 2018

Significance

Marine sediment holds the largest organic carbon pool on earth, where microbial transformation of carbon is considered a key process of carbon cycling.Bathyarchaeotaare among the most abundant and active groups of microorganisms in marine sediment. It has been suggested thatBathyarchaeotamay play a globally important role in the carbon cycling in the marine environment through fermentation of complex organic substances, acetogenesis, and methanogenesis based on metagenome analysis. Here we provide several lines of converging evidence suggesting the bathyarchaeotal group Bathy-8 is able to grow with lignin as an energy source and bicarbonate as a carbon source. Consequently, members of theBathyarchaeotaare probably important, previously unrecognized degraders of lignin.
Sulfur monoxide thermal release from an anthracene-based precursor, spectroscopic identification, and transfer reactivity
Authors: Joost Maximilian , Nava Matthew , Transue Wesley J. , Martin-Drumel Marie-Aline , McCarthy Michael C. , Patterson David , Cummins Christopher C.
Published: May 2018

Significance

The generation of highly reactive molecules under controlled conditions is desirable, as it allows exploration of synthetic chemistry and enables spectroscopic studies of such elusive species. We report here on the synthesis and reactivity of a precursor molecule that readily fragments with concomitant expulsion of dinitrogen and anthracene to release the highly reactive sulfur monoxide, a compound of interest for both synthetic chemists and astrochemists.
Arginine methylation is required for canonical Wnt signaling and endolysosomal trafficking
Authors: Albrecht Lauren V. , Ploper Diego , Tejeda-Muñoz Nydia , De Robertis Edward M.
Published: May 2018

Significance

Endocytosis plays a fundamental role in Wnt signaling, leading to the sequestration of cytosolic GSK3 kinase inside multivesicular endosomes. Here we show an unexpected role for the enzyme protein arginine methyltransferase 1 (PRMT1) during Wnt signaling. In the case of the soluble tumor suppressor transcription factor Smad4, modification of a particular arginine was required before this protein could be phosphorylated by GSK3. Wnt3a addition caused rapid endocytosis that strikingly expanded the cellular liquid-phase compartment within 5–20 min. Wnt-induced vesicles contained arginine-methylated proteins, GSK3 and PRMT1 itself, within membrane-bound organelles. The translocation of these proteins into multivesicular endosomes via microautophagy was essential for canonical Wnt signaling.
Oxidation behaviour of single crystal nickel-based superalloys: Intermediate temperature effects at 450–550°C
Authors: Evangelou A. , Soady K. A. , Lockyer S. , Gao N. , Reed P. A. S.
Published: May 2018

The oxidation behaviour of two single crystal Ni-based superalloys has been investigated at 450°C and 550°C. Isothermal oxidation was carried out for varying times and it was found that exposure resulted in a sub-micrometre thick oxide. The external and internal oxide kinetics were studied via high-resolution image analysis and both showed sub-parabolic growth rates. Thermogravimetric tests indicated that the overall oxidation growth obeys a near quartic power law while parabolic kinetics can describe the transient oxidation period. Characterisation of the resulting oxides was carried out using electron microscopy, energy dispersive spectroscopy and X-ray diffraction. Results from thermodynamic modelling of the oxide formation are also presented to further assess the postulated mechanism of low-temperature oxidation in these Ni-based superalloys.
Status of the large-scale commercial trawl fisheries in southern Lake Malawi
Authors: Kanyerere G. Z. , Kaonga D. , Mponda O. , Nkhoma B. , Ngulande E.
Published: May 2018

A study to assess the status of the large scale commercial fisheries operating in southern Lake Malawi was conducted using generalised linear modelling and Principles of Precautionary Approach. The generalised linear modelling analysis was used to standardise catch per unit of effort data from 1976 to 2009 and to determine the effects of fishing vessel characteristics such as engine size and hydro-acoustic devices on fish catch rates. The Precautionary Approach, through reference points like Bmax (reference point corresponding to period of relatively high fish catch rate), Bpa (reference point at which precautionary management action should be undertaken), Blim (limit reference point beyond which a fishery is considered seriously depleted) and Bcur (reference point corresponding to current fish catch rate), was used to assess the status of fish stocks using standardised fish catch rate which approximated fish biomass or stock size.

Results of the assessment indicated that the current fish biomass level in all three categories, bottom pair trawl, stern bottom trawl and stern mid-water trawl fisheries, is well above Blim, but is 9–12% above Bpa, which is very close suggesting that the fishery is fully exploited and precautionary management measures are required. Suggested measures included introduction of fishing closed season for the large scale commercial fisheries which will be dependent on the biology of the most important target fish stocks, relocation or reduction of fishing effort in the current fishing grounds and intensification of patrols to reduce incidences of illegal, unreported and unregulated fishing activities.
Protein kinase A activation: Something new under the sun?
Authors: Smith F. Donelson , Scott John D.
Published: May 2018

The role of autophosphorylation of the type II regulatory subunit in activation of protein kinase A (PKA) has been a longstanding question. In this issue, Isensee et al. (2018. J. Cell Biol. https://doi.org/10.1083/jcb.201708053) use antibody tools that selectively recognize phosphorylated RII and the catalytic subunit active site to reexamine PKA holoenzyme activation mechanisms in neurons.
Subcellular topography modulates actin dynamics and signaling in B-cells
Authors: Ketchum Christina M. , Sun Xiaoyu , Suberi Alexandra , Fourkas John T. , Song Wenxia , Upadhyaya Arpita
Published: May 2018

B-cell signaling activation is most effectively triggered by the binding of B-cell receptors (BCRs) to membrane-bound antigens. In vivo, B-cells encounter antigen on antigen-presenting cells (APC), which possess complex surfaces with convoluted topographies, a fluid membrane and deformable cell bodies. However, whether and how the physical properties of antigen presentation affect B-cell activation is not well understood. Here we use nanotopographic surfaces that allow systematic variation of geometric parameters to show that surface features on a subcellular scale influence B-cell signaling and actin dynamics. Parallel nanoridges with spacings of 3 microns or greater induce actin intensity oscillations on the ventral cell surface. Nanotopography-induced actin dynamics requires BCR signaling, actin polymerization, and myosin contractility. The topography of the stimulatory surface also modulates the distribution of BCR clusters in activated B-cells. Finally, B-cells stimulated on nanopatterned surfaces exhibit intracellular calcium oscillations with frequencies that depend on topography. Our results point to the importance of physical aspects of ligand presentation, in particular, nanotopography for B-cell activation and antigen gathering.
Hic-5 expression is a major indicator of cancer cell morphology, migration, and plasticity in three-dimensional matrices
Authors: Gulvady Anushree C. , Dubois Fatemeh , Deakin Nicholas O. , Goreczny Gregory J. , Turner Christopher E.
Published: May 2018

The focal adhesion proteins Hic-5 and paxillin have been previously identified as key regulators of MDA-MB-231 breast cancer cell migration and morphologic mesenchymal-amoeboid plasticity in three-dimensional (3D) extracellular matrices (ECMs). However, their respective roles in other cancer cell types have not been evaluated. Herein, utilizing 3D cell–derived matrices and fibronectin-coated one-dimensional substrates, we show that across a variety of cancer cell lines, the level of Hic-5 expression serves as the major indicator of the cells primary morphology, plasticity, and in vitro invasiveness. Domain mapping studies reveal sites critical to the functions of both Hic-5 and paxillin in regulating phenotype, while ectopic expression of Hic-5 in cell lines with low endogenous levels of the protein is sufficient to induce a Rac1-dependent mesenchymal phenotype and, in turn, increase amoeboid-mesenchymal plasticity and invasion. We show that the activity of vinculin, when coupled to the expression of Hic-5 is required for the mesenchymal morphology in the 3D ECM. Taken together, our results identify Hic-5 as a critical modulator of tumor cell phenotype that could be utilized in predicting tumor cell migratory and invasive behavior in vivo.
Septins regulate junctional integrity of endothelial monolayers
Authors: Kim Joanna , Cooper John A.
Published: May 2018

Junctional integrity of endothelial monolayers is crucial to control movement of molecules and cells across the endothelium. Examining the structure and dynamics of cell junctions in endothelial monolayers, we discovered a role for septins. Contacts between adjacent endothelial cells were dynamic, with protrusions extending above or below neighboring cells. Vascular endothelial cadherin (VE-cadherin) was present at cell junctions, with a membrane-associated layer of F-actin. Septins localized at cell-junction membranes, in patterns distinct from VE-cadherin and F-actin. Septins assumed curved and scallop-shaped patterns at junctions, especially in regions of positive membrane curvature associated with actin-rich membrane protrusions. Depletion of septins led to disrupted morphology of VE-cadherin junctions and increased expression of VE-cadherin. In videos, septin-depleted cells displayed remodeling at cell junctions; regions with VE-cadherin were broader, and areas with membrane ruffling were wider. Septin depletion and junction disruption led to functional loss of junctional integrity, revealed by decreased transendothelial electric resistance and increased transmigration of immune cells. We conclude that septins, as cytoskeletal elements associated with the plasma membrane, are important for cell junctions and junctional integrity of endothelial monolayers, functioning at regions of positive curvature in support of actin-rich protrusions to promote cadherin-based cell junctions.
Kif15 functions as an active mechanical ratchet
Authors: McHugh Toni , Drechsler Hauke , McAinsh Andrew D. , Carter Nicolas J. , Cross Robert A.
Published: May 2018

Kif15 is a kinesin-12 that contributes critically to bipolar spindle assembly in humans. Here we use force-ramp experiments in an optical trap to probe the mechanics of single Kif15 molecules under hindering or assisting loads and in a variety of nucleotide states. While unloaded Kif15 is established to be highly processive, we find that under hindering loads, Kif15 takes <∼10 steps. As hindering load is increased, Kif15 forestep:backstep ratio decreases exponentially, with stall occurring at 6 pN. In contrast, under assisting loads, Kif15 detaches readily and rapidly, even from its AMPPNP state. Kif15 mechanics thus depend markedly on the loading direction. Kif15 interacts with a binding partner, Tpx2, and we show that Tpx2 locks Kif15 to microtubules under both hindering and assisting loads. Overall, our data predict that Kif15 in the central spindle will act as a mechanical ratchet, supporting spindle extension but resisting spindle compression.
Inhomogeneous Dual Diophantine Approximation on Affine Subspaces
Authors: Beresnevich Victor , Ganguly Arijit , Ghosh Anish , Velani Sanju
Published: May 2018

We prove the convergence and divergence cases of an inhomogeneous Khintchine–Groshev-type theorem for dual approximation restricted to affine subspaces in $\mathbb{R} ^n$. The divergence results are proved in the more general context of Hausdorff measures.
Population health: a nursing action plan
Authors: Ariosto Deborah A , Harper Ellen M , Wilson Marisa L , Hull Susan C , Nahm Eun-Shim , Sylvia Martha L
Published: May 2018

The passage of the Affordable Care Act shifted the focus of health care from individual, patient specific, episodic care, towards health management of groups of people with an emphasis on primary and preventive care. Population health management assists to attain and maintain health while improving quality and lowering costs. The recent Catalyst for Change report creates an urgent call for harnessing the power of nurses—in our communities, schools, businesses, homes and hospitals—to build capacity for population health. Informatics Nurse Specialists are prepared to bridge roles across practice, research, education, and policy to support this call. Each year, the AMIA Nursing Informatics Working Group convenes an expert panel to reflect on the “hot topics” of interest to nursing. Not surprisingly, the 2017 topic was on the current state and challenges of population health. The following summary reflects the panel’s perspectives and recommendations for action.
Fine-Scale Population Genetic Structure and Within-Tree Distribution of Mating Types of Venturia effusa, Cause of Pecan Scab in the United States
Authors: Bock Clive H. , Young Carolyn A. , Stevenson Katherine L. , Charlton Nikki D.
Published: May 2018

Scab (caused by Venturia effusa) is the major disease of pecan in the southeastern United States. There is no information available on the fine-scale population genetic diversity or the occurrence of clonal types at small spatial scales that provides insight into inoculum sources and dispersal mechanisms, and potential opportunity for sexual reproduction. To investigate fine-scale genetic diversity, four trees of cultivar Wichita (populations) were sampled hierarchically: within each tree canopy, four approximately evenly spaced terminals (subpopulations) were selected and up to six leaflets (sub-subpopulations) were sampled from different compound leaves on each terminal. All lesions (n = 1 to 8) on each leaflet were sampled. The isolates were screened against a panel of 29 informative microsatellite markers and the resulting multilocus genotypes (MLG) subject to analysis. Mating type was also determined for each isolate. Of 335 isolates, there were 165 MLG (clonal fraction 49.3%). Nei’s unbiased measure of genetic diversity for the clone-corrected data were moderate to high (0.507). An analysis of molecular variance demonstrated differentiation (P = 0.001) between populations on leaflets within individual terminals and between terminals within trees in the tree canopies, with 93.8% of variance explained among isolates within leaflet populations. Other analyses (minimum-spanning network, Bayesian, and discriminant analysis of principal components) all indicated little affinity of isolate for source population. Of the 335 isolates, most unique MLG were found at the stratum of the individual leaflets (n = 242), with similar total numbers of unique MLG observed at the strata of the terminal (n = 170), tree (n = 166), and orchard (n = 165). Thus, the vast majority of shared clones existed on individual leaflets on a terminal at the scale of 10s of centimeters or less, indicating a notable component of short-distance dispersal. There was significant linkage disequilibrium (P < 0.001), and an analysis of Psex showed that where there were multiple encounters of an MLG, they were most probably the result of asexual reproduction (P < 0.05) but there was no evidence that asexual reproduction was involved in single or first encounters of an MLG (P > 0.05). Overall, the MAT1-1-1 and MAT1-2-1 idiomorphs were at equilibrium (73:92) and in most populations, subpopulations, and sub-subpopulations. Both mating types were frequently observed on the same leaflet. The results provide novel information on the characteristics of populations of V. effusa at fine spatial scales, and provide insights into the dispersal of the organism within and between trees. The proximity of both mating idiomorphs on single leaflets is further evidence of opportunity for development of the sexual stage in the field.
Left Lateral Table Tilt for Elective Cesarean Delivery Under Spinal Anesthesia Has No Effect on Neonatal Acid-Base Status
Authors: Lee A.J. , Landau R. , Mattingly J.L. , Meenan M.M. , Corradini B. , Wang S. , Goodman S.R. , Smiley R.M.
Published: May 2018

(Anesthesiology. 2017;127(2):241–249)

Cesarean delivery in the supine position may result in maternal hypotension, aortocaval compression, and fetal complications. Uterine displacement by left lateral tilt is currently recommended to prevent these outcomes. Tilting was associated with superior neonatal acid-base status in studies during the 1970s. The current use of vasopressor agents to effectively prevent maternal spinal hypotension calls into question the necessity of tilting, particularly since the target tilt of 15 degrees is rarely achieved. This study hypothesized that, using a fluid coload with spinal anesthesia and a phenylephrine infusion to maintain baseline systolic blood pressure, neonatal acid base status would not be affected by maternal position (supine vs. tilted) in women delivering via elective cesarean delivery.
Noninfectious Fever in the Near-Term Pregnant Rat Induces Fetal Brain Inflammation: A Model for the Consequences of Epidural-associated Maternal Fever
Authors: Segal S. , Pancaro C. , Bonney I. , Marchand J.E.
Published: May 2018

(Anesth Analg. 2017;125(6):2134–2140)

Intrapartum fever of noninfectious etiology during deliveries in women with labor epidural analgesia may adversely affect the developing fetal brain. A proinflammatory cytokine, interleukin (IL)-6, found to be present at increased levels in epidural-associated maternal fever, has been linked to neonatal brain injury. As there is no comprehensive animal model of labor epidural analgesia, the authors of the present study developed a model of noninfectious inflammatory fever in the near-term pregnant rat using IL-6 levels comparable to those found in human patients with labor epidural analgesia-associated fever. They hypothesized that brief administration of IL-6 would induce a core temperature increase in the dams and induce neuroinflammation in the fetus.
Maternal Death Due to Amniotic Fluid Embolism: A National Study in France
Authors: Bonnet M.P. , Zlotnik D. , Saucedo M. , Chassard D. , Bouvier-Colle M.H. , Deneux-Tharaux C.
Published: May 2018

(Anesth Analg. 2018;126(1):175–182)

Signs and symptoms of amniotic fluid embolism (AFE) vary greatly and are not specific to AFE, making it a difficult condition to diagnose and treat. Recently, the Society for Maternal-Fetal Medicine (SMFM) and the AFE Foundation proposed 4 uniform diagnostic criteria to help identify cases of AFE for research purposes. These criteria have not been tested on a specific population. The authors of the present study applied these criteria to maternal deaths attributed to AFE between 2007 and 2011, as identified by a national experts committee from the French Confidential Enquiry into Maternal Deaths, to evaluate its potential as a diagnostic tool. Furthermore, they described the epidemiology, clinical characteristics, and management of AFE by the presence or absence of all 4 diagnostic criteria.
Patient-Controlled Analgesia With Remifentanil Versus Alternative Parenteral Methods for Pain Management in Labour: A Cochrane Systematic Review
Authors: Jelting Y. , Weibel S. , Afshari A. , Pace N.L. , Jokinen J. , Artmann T. , Eberhart L.H.J. , Kranke P.
Published: May 2018

(Anaesthesia. 2017;72(8):1016–1028)

Guidelines from both the American Society of Anesthesiologists (ASA) and the American College of Obstetricians and Gynecologists (ACOG) recommend epidural analgesia as the most effective and flexible analgesic option for labor pain management, but some laboring women have contraindications to neuraxial analgesia and others may prefer alternatives. This Cochrane systematic review analyzed the effectiveness of intravenous remifentanil patient-controlled analgesia (PCA) compared with other labor analgesia techniques as measured by patient satisfaction and adverse maternal or neonatal effects.
Point-of-Care Viscoelastic Testing Improves the Outcome of Pregnancies Complicated by Severe Postpartum Hemorrhage
Authors: Snegovskikh D. , Souza D. , Walton Z. , Dai F. , Rachler R. , Garay A. , Snegovskikh V.V. , Braveman F.R. , Norwitz E.R.
Published: May 2018

(J Clin Anesth. 2018;44:50–56)

Standardized hospital protocols that address severe postpartum hemorrhage (PPH), or estimated blood loss >1500 mL following delivery, generally follow principles of empiric resuscitation, favoring early transfusion of high volumes of fresh frozen plasma, packed red blood cells, and platelets. However, it has been suggested that blood product resuscitation should be individualized and adjusted according to the results of point-of-care viscoelastic testing (PCVT). In the present study, the authors compared clinical outcomes [volume of transfused blood products, rate of volume overload, and rate of intensive care unit (ICU) admission] and hospital costs for patients with severe PPH managed with and without PCVT-guided transfusion protocol.
Reducing Maternal Mortality in Papua New Guinea: Contextualizing Access to Safe Surgery and Anesthesia
Authors: Dennis A.T.
Published: May 2018

(Anesth Analg. 2018;126(1):252–259)

Papua New Guinea (PNG), a low–middle-income country with a population of 7.6 million and a poverty ranking of 158 of 188 countries, has an estimated maternal mortality rate of 215 (range, 98 to 733) per 100,000 live births. This is one of the world’s highest maternal mortality rates, with the comparable statistic in Australia being 7.1 deaths per 100,000 live births. Reasons for maternal death in PNG are not limited to pathologies usually associated with maternal death, such as obstetric hemorrhage, sepsis, high blood pressure, etc., but also to fundamental in-country systemic issues, including leadership and governance, a dispersed population in the rural highlands, shortage of health workers, limited access to water and information systems, fragile health infrastructure, poor focus on the social determinants of health, and limited access to safe surgery and anesthesia. Therefore, addressing pathologies that result in death will have little impact on the maternal mortality issue in PNG. Instead, as discussed by the World Health Organization’s 2015 publication on “global strategy for women’s, children’s, and adolescent’s health,” key areas for improvement in maternal health lie in strong country plans, integrated health delivery services, life-saving interventions and commodities, adequate number of skilled and well-equipped health workers, access to safe surgery and anesthesia, and improved monitoring/evaluation/accountability. The authors of the present narrative discussed the current situation in PNG and possible approaches to reducing maternal mortality via a discussion of enabling environments and key times for intervention.
Foley Catheterization Versus Oral Misoprostol for Induction of Labour in Hypertensive Women in India (INFORM): A Multicenter, Open-label, Randomized Controlled Trial
Authors: Mundle S. , Bracken H. , Khedikar V. , Mulik J. , Faragher B. , Easterling T. , Leigh S. , Granby P. , Haycox A. , Turner M.A. , Alfirevic Z. , Winikoff B. , Weeks A.D.
Published: May 2018

(Lancet. 2017;390(10095):669–680)

Hypertensive disorders, including preeclampsia, affect 10% of all pregnancies, with preeclampsia and eclampsia accounting for roughly 14% of global maternal deaths annually. While treatment with magnesium sulfate or antihypertensive drugs can reduce maternal morbidity and mortality, the best preventive method is timely vaginal delivery. Low-dose oral misoprostol and the Foley catheter are 2 low-cost cervical ripening methods recommended for use in low-resource settings, where most morbidity and mortality associated with preeclampsia occurs. However, few studies have compared these 2 methods directly. The INFORM trial aimed to compare the efficacy, safety, acceptability, and cost-effectiveness of labor induction via oral misoprostol versus Foley balloon catheter in women with gestational hypertension in a low-resource setting.
Maternal Age is a Risk Factor for Cesarean Section Following Induction of Labor
Authors: Dunn L. , Kumar S. , Beckmann M.
Published: May 2018

(Aust N Z J Obstet Gynaecol. 2017;57(4):426–431)

Women 35 years or older, considered advanced maternal age (AMA), are more likely to experience complications and adverse neonatal outcomes including stillbirth. Pregnancies in these older women are increasing in western countries. Scheduled induction of labor in AMA pregnancies has been increasingly practiced; however, data concerning the outcomes of induction of labor (IOL) in AMA pregnancies are limited. This study explored the relationship between IOL and cesarean delivery in AMA women.
Fixed Time Interval Compared With On-Demand Oral Analgesia Protocols for Postcesarean Pain: A Randomized Controlled Trial
Authors: Yefet E. , Taha H. , Salim R. , Hasanein J. , Carmeli Y. , Schwartz N. , Nachum Z.
Published: May 2018

(BJOG. 2017;124(7):1063–1070)

Effective postcesarean analgesia is important as untreated pain can impair maternal bonding with her infant and decrease the rate of successful breastfeeding. Postoperative pain can also lead to decreased ambulation, which is associated with an increased risk of thromboembolic events and other postoperative complications. Although many options for postcesarean pain treatment are available, the use of oral analgesic medications is simple and may promote maternal mobilization. However, the data are limited and inconclusive regarding the superiority of dosing oral analgesics using a fixed time interval or on patient demand. This open-label, parallel-group, randomized controlled trial aimed to compare efficacy, safety, and patient satisfaction when administering a combination of oral pain relievers on patient demand versus a fixed time interval for the treatment of postcesarean pain in the first 48 hours following surgery.
Pregnancy and the apoptotic pathway in experimental melanoma
Authors: Facina Anamaria S. , Facina Gil , Guerreiro da Silva Ismael D.C. , Corrêa Silvana A.A. , Alexandre Sandra M. , Logullo Ângela F. , Hosomi Jorge K. , Nakamura Mary U.
Published: May 2018

Pregnancy-associated melanoma is defined as melanoma diagnosed during pregnancy or within 1 year of delivery. The association of pregnancy with melanoma is well known, but its underlying molecular mechanisms of association are poorly understood. The aim was to assess the expression of apoptosis-related genes in melanoma tumors during pregnancy in an attempt to elucidate the molecular mechanisms underlying apoptosis-driven activation of melanoma cells in this period. Mice were allocated across two experimental groups (nonpregnant and pregnant) and implanted with the melanoma cell line BF16-F10. Tumor tissue was collected for RNA extraction and purification, and gene expression was quantified using the mouse apoptosis RT2ProfilerTM PCR array. Different intracellular apoptotic pathways were activated (positively or negatively) by pregnancy in tumor cells: intrinsic (21.5%), extrinsic (32%), caspase (14%), apoptosis (21.5%), and caspase-activated DNase (11%). The proportion of upregulated genes for each of these pathways was 100, 30, 50, 17, and 0%, respectively. MetaCore software was then used to analyze gene ontology processes and pathways by building networks. Among the gene ontology processes, the majority of differentiated genes were related to the apoptotic process. The main pathway activated by pregnancy was the intrinsic one (genes Api-5, Bcl2-L1, Birc-2, Birc-3, Bok, and Trp53bp2). Pregnancy activates the intrinsic apoptosis pathway to stimulate caspases 7 and 9, but the final balance is inhibition of apoptosis mechanisms. In mice, pregnancy cannot promote or worsen melanoma.
Detection Rate of High-Grade Squamous Intraepithelial Lesions as a Quality Assurance Metric for High-Resolution Anoscopy in HIV-Positive Men
Authors: Siegenbeek van Heukelom Matthijs L. , Marra Elske , Cairo Irina , Van Eeden Arne , Schim van der Loeff Maarten F. , De Vries Henry J.C. , Prins Jan M.
Published: May 2018

BACKGROUND:

High-resolution anoscopy-guided biopsies are the gold standard for identifying anal intraepithelial neoplasia, but diagnosing high-grade squamous intraepithelial lesions depends on the skills of the anoscopist.

OBJECTIVE:

This study aims to validate the high-grade squamous intraepithelial lesion detection rate as a quality assurance metric for high-resolution anoscopy in HIV-positive men.

DESIGN:

This is a retrospective study.

SETTING:

This study was conducted at 3 HIV outpatient clinics in Amsterdam, The Netherlands.

PATIENTS:

HIV-positive men who have sex with men were selected for this study.

MAIN OUTCOME MEASURES:

We analyzed the high-grade squamous intraepithelial lesion detection rate per high-resolution anoscopy, the mean number of biopsies taken, and the mean high-grade squamous intraepithelial lesion rate per biopsy in time-subsequent groups for 7 anoscopists performing high-resolution anoscopy.

RESULTS:

Seven anoscopists performed high-resolution anoscopy in 1340 HIV-positive men who have sex with men. The overall high-grade squamous intraepithelial lesion detection rate for all 7 anoscopists combined increased significantly over time, from 27% to 40% (p < 0.001; OR, 1.15; 95% CI, 1.08–1.23 per 50 high-resolution anoscopies). The mean number of biopsies increased significantly from 1.4 (22% high-grade squamous intraepithelial lesions per biopsy) to 2.0 biopsies per patient (29% high-grade squamous intraepithelial lesions per biopsy) (p < 0.001). Three anoscopists showed a significant increase in proportion of high-grade squamous intraepithelial lesions per biopsy with increasing experience.

LIMITATIONS:

There were statistically significant differences, with limited clinical significance, in the characteristics of patient populations between anoscopists and clinics.

CONCLUSIONS:

We found significant variations in the high-grade squamous intraepithelial lesion detection rate among anoscopists performing high-resolution anoscopy in HIV-positive men who have sex with men. The high-grade squamous intraepithelial lesion detection rate and mean high-grade squamous intraepithelial lesion rate per biopsy can be used as a quality assurance metric to follow up the learning curve of high-resolution anoscopists. See Video Abstract at http://links.lww.com/DCR/A555.