bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Aggregation of Marketed Recombinant FVIII Products: Biochemical Evidence and Functional Effects
Authors: De Cristofaro Raimondo , Sacco Monica , Lancellotti Stefano , Berruti Federico , Garagiola Isabella , Valsecchi Carla , Basso Maria , Di Stasio Enrico , Peyvandi Flora
Published: May 2019

Background Recombinant (rec-) coagulation factor VIII concentrates available for hemophilia A (HA) treatment differ in cell line production and structure, which could affect their pharmacodynamics and immunogenicity. Clinical trials showed that previously untreated patients with severe HA present higher rates of inhibitor development if treated with rec-FVIII products and that differences do exist as to inhibitor's formation among different rec-FVIII products. This finding could arise from several causes, such as absence of von Willebrand factor, different glycosylation profiles, or processes of molecular aggregation of the recombinant FVIII molecules.

Objectives/Methods In this study, using size exclusion high-performance liquid chromatography (SE-HPLC), dynamic light scattering (DLS) spectroscopy, and functional biochemical assays, we investigated the purity grade, FX activating ability, and aggregation status of three recombinant marketed products (Advate [Baxalta], Refacto AF [Pfizer], and Kogenate [Bayer]).

Results The overall analysis of the results obtained with SE-HPLC and DLS spectroscopy showed that the three recombinant FVIII concentrates contain low but significant amounts of molecular aggregates. This phenomenon was less evident for the Advate product. Molecular aggregation negatively affects the in vitro pharmacodynamics of the concentrates with higher aggregates' content.

Conclusions This study shows that the three pharmaceutical formulations of recombinant FVIII contain variable amounts of molecular aggregates after their reconstitution at therapeutic concentrations. This phenomenon negatively affects the in vitro potency of the products with higher aggregates' content and might be invoked as a contributing cause of their increased risk to induce the formation of FVIII inhibitors.
Creation of a Multicenter Pediatric Inpatient Data Repository Derived from Electronic Health Records
Authors: Hornik Christoph , Atz Andrew , Bendel Catherine , Chan Francis , Downes Kevin , Grundmeier Robert , Fogel Ben , Gipson Debbie , Laughon Matthew , Miller Michael , Smith Michael , Livingston Chad , Kluchar Cindy , Heath Anne , Jarrett Chanda , McKerlie Brian , Patel Hetalkumar , Hunter Christina ,   on behalf of the Best Pharmaceuticals for Children Act–Pediatric Trials Network
Published: May 2019

Background Integration of electronic health records (EHRs) data across sites and access to that data remain limited.

Objective We developed an EHR-based pediatric inpatient repository using nine U.S. centers from the National Institute of Child Health and Human Development Pediatric Trials Network.

Methods A data model encompassing 147 mandatory and 99 optional elements was developed to provide an EHR data extract of all inpatient encounters from patients <17 years of age discharged between January 6, 2013 and June 30, 2017. Sites received instructions on extractions, transformation, testing, and transmission to the coordinating center.

Results We generated 177 staging reports to process all nine sites' 147 mandatory and 99 optional data elements to the repository. Based on 520 prespecified criteria, all sites achieved 0% errors and <2% warnings. The repository includes 386,159 inpatient encounters from 264,709 children to support study design and conduct of future trials in children.

Conclusion Our EHR-based data repository of pediatric inpatient encounters utilized a customized data model heavily influenced by the PCORnet format, site-based data mapping, a comprehensive set of data testing rules, and an iterative process of data submission. The common data model, site-based extraction, and technical expertise were key to our success. Data from this repository will be used in support of Pediatric Trials Network studies and the labeling of drugs and devices for children.
Different Strategies in Making Transseptal Portal for the Different Purposes
Authors: Lee Yong Seuk , Kim Tae Woo , Lee Eui Soo , Lee Kyoung Hwan , Lee Seung Hoon
Published: May 2019

The purpose of this study was to find the most suitable and safe position of the transseptal portal in anatomic anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstructions. The hypothesis of this study was that area and position of the transseptal portal are different between ACL and PCL reconstructions for the observation of native footprint. A matched-pair comparison study was conducted on the arthroscopic images of 100 consecutive patients who underwent ACL reconstruction and 50 consecutive patients who underwent PCL reconstruction. The transseptum was divided into six compartments. The opened compartments for each surgery were then evaluated to find which anatomical structures are well seen. The anterior middle and upper parts were necessary for the ACL reconstruction, whereas middle and lower portions of the anterior and posterior compartments were necessary for the PCL reconstruction. A larger opening was necessary for PCL reconstruction than that for ACL reconstruction. The ACL posterior one-third, ACL femoral attachment, and apex of the deep cartilage margin (DCM) were viewed in 100% of the patients during ACL reconstruction. The PCL posterior one-third, PCL tibial attachment, PCL fovea margin, and medial meniscus around posterior margin were always viewed during PCL reconstruction. The anterior part of the septum, from the middle to the upper portions of the transseptum, was necessary to be opened for visualization of the femoral footprint and DCM of the lateral femoral condyle during ACL reconstruction. The anterior and posterior parts of the septum, from the middle to the lower portions of the transseptum, were necessary for excellent visualization of the PCL tibial footprint during PCL reconstruction. These paths of the transseptal portal for each surgery will help surgeons obtain both anatomic footprint restoration and maximal remnant preservation through the most suitable and safe means. This is a case–control study; level of evidence is 3.
Do Individual Differences in Physical Therapists' Skills Affect Postoperative Results of Total Knee Arthroplasty?
Authors: Fujii Tadashi , Nishio Naoyuki , Bandou Minenari , Kitano Shuji , Noboru Marehoshi , Seko Munehito , Inagaki Yusuke , Tanaka Yasuhito
Published: May 2019

We investigated variations in postoperative outcomes of total knee arthroplasty which were dependent on the physical therapist (PT) who performed rehabilitation while keeping other parameters as uniform as possible. Seventy-nine among 690 knees were selected based on strict inclusion and exclusion criteria. Patients were randomly assigned to five PTs, who had from 2 to 21 years of experience. Range of motion (ROM) on postoperative days (PODs) 1, 3, 7, and 14 and at postoperative months 3, 6, and 12, results of timed up and go (TUG) test on POD 14, time to walking with a single cane, and time to climbing stairs, were evaluated. There were significant differences until POD 3, and no significant differences afterward in flexion. There was a significant difference on POD 1 only in extension. The TUG test showed no significant difference, but there were significant differences at the time of walking with a single cane and climbing stairs. The time taken to achieve rehabilitation, which was determined subjectively by each PT, differed among therapists, but differences in ROM were present in early period. Therefore, ROM after surgery is not affected by differences between PTs.
Evaluation of the PROMIS Physical Function Computer Adaptive Test in Patients Undergoing Knee Surgery
Authors: Miles Megan , Nadarajah Vidushan , Jauregui Julio J. , Dubina Andrew G. , Smuda Michael P. , Bennett Craig H. , Packer Jonathan D. , Henn R. Frank
Published: May 2019

A cross-sectional analysis of data derived from patients undergoing knee surgery at a single institution was conducted. The objectives of the study were to (1) compare how the Patient-Reported Outcomes Measurement Information System physical function (PROMIS PF) computer adaptive test performs against the International Knee Documentation Committee (IKDC) Subjective Knee Form in evaluating functional status, and (2) to determine demographic, clinical, and psychosocial correlates of each outcome measure in an urban population undergoing a variety of knee surgeries. We hypothesized that there would be a strong correlation between PROMIS PF and IKDC, with minimal floor and ceiling effects, and similar clinical correlates. The sample consisted of 412 patients undergoing knee surgery. Bivariate and multivariable statistical analyses were performed to identify significant independent predictors. The PROMIS PF and IKDC scores were strongly correlated (r
s = 0.71, p < 0.001), and neither exhibited floor nor ceiling effects. Lower body mass index, no preoperative opioid use, lower Charlson comorbidity index score, employment, and lower income were found to be significant independent predictors for better scores on both PROMIS PF and IKDC. Patients undergoing total knee arthroplasty had significantly lower PROMIS PF and IKDC scores (p < 0.05). Potential explanations for these findings are presented, and clinical implications are discussed.
Vein Size Mismatch Increases Flap Failure in Lower Extremity Trauma Free Flap Reconstruction
Authors: Lee Z-Hye , Alfonso Allyson R. , Stranix John T. , Anzai Lavinia , Daar David A. , Ceradini Daniel J. , Levine Jamie P. , Saadeh Pierre B. , Thanik Vishal
Published: May 2019

Background Venous outflow problems are the most common reasons for perioperative flap complications. Size mismatch in venous anastomoses poses a theoretical problem by promoting turbulent flow and subsequent thrombus formation. The purpose of this study was to determine if increased vein size mismatch is predictive of flap failure.

Methods Retrospective review of our institutional flap registry from 1979 to 2016 identified 410 free flaps performed for reconstruction of lower extremity trauma. Patient demographics, flap characteristics, and flap outcomes were examined. Venous size mismatch was defined as a difference in size ≥ 1 mm between the recipient vein and flap vein.

Results Vein size mismatch ≥ 1mm was present in 17.1% (n = 70) of patients. The majority of anastomoses were end-to-end (n = 379, 92.4%), and end-to-side anastomoses were preferentially used in the presence of vein size mismatch (p < 0.001). Major complications occurred in 119 (29%) flaps, with 35 (8.5%) partial flap losses and 34 (8.3%) total flap losses. Looking specifically at flaps with end-to-end venous anastomoses, venous size mismatch was associated with increased total flap failure (p = 0.031) and takeback for vascular compromise (p = 0.030). Recipient vein size relative to flap vein size (larger or smaller) had no effect on flap outcomes. Multivariable regression analysis controlling for age, sex, flap type, number of veins, recipient vein size, flap vein size, venous coupler use, and vein size mismatch demonstrated that flaps with ≥ 1 mm vein mismatch were predictive of total flap failure (p = 0.045; odds ratio: 2.58).

Conclusion Flaps with vein size mismatch ≥ 1 mm demonstrated increased flap complication rates in the setting of end-to-end venous anastomoses. End-to-side anastomosis was preferentially used in vein size mismatch and carried a higher risk of flap failure. Our results support using veins of similar size for anastomosis whenever feasible to protect against flap complications.
Probing and possible application of the QED vacuum with micro-bubble implosions induced by ultra-intense laser pulses
Authors: Koga James K. , Murakami Masakatsu , Arefiev Alexey V. , Nakamiya Yoshihide
Published: May 2019

The interaction of micro-bubbles with ultra-intense laser pulses has been shown to generate ultra-high proton densities and correspondingly high electric fields. We investigate the possibility of using such a combination to study the fundamental physical phenomenon of vacuum polarization. With current or near-future laser systems, measurement of vacuum polarization via the bending of gamma rays that pass near imploded micro-bubbles may be possible. Since it is independent of photon energy to within the leading-order solution of the Heisenberg–Euler Lagrangian and the geometric optics approximation, the corresponding index of refraction can dominate the indices of refraction due to other effects at sufficiently high photon energies. We consider the possibility of its application to a transient gamma-ray lens.
Light assisted multilevel resistive switching memory devices based on all-inorganic perovskite quantum dots
Authors: Chen Zhiliang , Zhang Yating , Yu Yu , Cao Mingxuan , Che Yongli , Jin Lufan , Li Yifan , Li Qingyan , Li Tengteng , Dai Haitao , Yang Junbo , Yao Jianquan
Published: May 2019

All-inorganic perovskite quantum dots (APQDs) have emerged as excellent materials which have been widely used in numerous micro-nano photoelectric devices. However, resistive random access memory (RRAM) devices based on APQDs are relatively scarce. In this work, RRAM based on CsPbBr3 APQDs prepared by the solution processed method was fabricated at room temperature. The sandwich structure memory device shows high reproducibility, good data retention ability, and light assisted multilevel storage capability. The resistance ratio (ON/OFF) of the RRAM device between the high resistance state and the low resistance state reaches almost 107. Additionally, the device exhibits high performances under low power consumption—low reading voltage (−0.3 V) and operation voltage (−2.4 V/1.55 V). It is suggested that the connection and rupture of conducting filaments, which are formed by Br vacancies under an electric field, are responsible for the resistive switching effect. Our work provides an opportunity to develop the next generation high-performance and stable nonvolatile memory devices.
Artifact-free optical spin–orbit torque magnetometry
Authors: Kim Joo-Sung , Park Yong-Keun , Whang Hyun-Seok , Park Jung-Hyun , Min Byoung-Chul , Choe Sug-Bong
Published: May 2019

Here, we demonstrate an optical spin–orbit torque (SOT) measurement scheme that is free from artifacts such as the optic planar Hall effect (PHE) and the optic anomalous Nernst effect (ANE). Such PHE and ANE signals complicate the SOT analysis in the electrical harmonic measurement method. Our optical setup utilizes photoelastic modulation and balanced detection to measure the polar magneto-optic Kerr effect (pMOKE) signal exclusively. We verified the separation of the pMOKE signal in the Pt/Py bilayer sample with a sizable optic PHE. Our method uses a single measurement principle and reduces the analysis complexity, and thus could help expand the scope of SOT studies.
Mach-Zehnder interferometry investigations in drying of water-saturated porous materials
Authors: Bhatia Anuradha , Roth Norbert , Weigand Bernhard
Published: May 2019

An experimental study of the drying behavior of water-saturated porous materials has been conducted. Two measurement techniques, namely, gravimetry and interferometry, have been utilized simultaneously. A white-light Mach–Zehnder interferometer has been used to measure the concentration gradients in the test cell, which occur as a result of the drying process. The interferograms, as well as the weight of the materials, have been measured and recorded, as they dry and reach equilibrium with the ambient air. The weight-loss data, which are obtained by gravimetry, are then used as a boundary condition to solve Crank’s surface evaporation equation. Upon solving Crank’s equation for surface evaporation, the concentration gradient above the drying substrate has been obtained. The concentration gradients in the test cell obtained by both measurement techniques have been compared.
Radio frequency wave interactions with a plasma sheath: The role of wave and plasma sheath impedances
Authors: Myra J. R. , Kohno H.
Published: May 2019

Radio frequency (RF) sheaths form near surfaces where plasma and strong RF fields coexist. The effect of these RF sheaths on wave propagation near the boundary can be characterized by an effective sheath impedance that includes both resistive and capacitive contributions describing RF sheath rectification and RF power absorption in the sheath [J. R. Myra and D. A. D'Ippolito, Phys. Plasmas 22, 062507 (2015)]. Here, we define a dimensionless parameter, the ratio of incoming wave impedance to the sheath impedance, which determines the characteristics of the interaction, ranging from quasi-conducting to quasi-insulating, or in the case of matched impedances, to either perfect absorption or a sheath-plasma resonance. A semi-analytical analysis is carried out for electrostatic slow waves in the ion cyclotron range of frequencies. For the propagating slow wave case, where the incident wave is partially reflected, the fraction of power dissipated in the sheath is calculated. For the evanescent slow wave case, which admits a sheath-plasma resonance, an amplification factor is calculated. Using the impedance ratio approach, RF sheath interactions are characterized for a range of RF wave and plasma parameters including plasma density, magnetic field angle with respect to the surface, wave frequency, and wave-vector components tangent to the surface. For a particularly interesting example case, results are compared with the rfSOL code [H. Kohno and J. R. Myra, Comput. Phys. Commun. 220, 129 (2017)]. Finally, electromagnetic effects, absent from the semi-analytical analysis, are assessed.
Turn-off mechanisms in thin-film source-gated transistors with applications to power devices and rectification
Authors: Bestelink E. , Landers T. , Sporea R. A.
Published: May 2019

We describe the physics of the turn-off mechanism in source-gated transistors (SGTs), which is distinct from that of conventional thin-film field-effect transistors and allows significantly lower off currents, particularly in depletion-mode devices. The “n-type” SGT enters its off state when the potential applied across the semiconductor layer is decreased to low positive values or made negative through the applied gate bias, thus impeding charge injection from the source contact. Measurements on polysilicon devices were supported with TCAD simulations using Silvaco Atlas. Alongside the other known benefits of SGTs, including low saturation voltage, tolerance to process variations, and high intrinsic gain, the ability to efficiently block current at high negative gate voltages suggests that these devices would be ideal elements in emerging thin-film power management and rectification circuits.
SU
q
(3) corepresentations and bivariate q-Krawtchouk polynomials
Authors: Bergeron G. , Koelink E. , Vinet L.
Published: May 2019

The matrix elements of unitary SUq(3) corepresentations, which are analogs of the symmetric powers of the natural representation, are shown to be the bivariate q-Krawtchouk orthogonal polynomials, thus, providing an algebraic interpretation of these polynomials in terms of quantum groups.
Multifunctional weak measurement system that can measure the refractive index and optical rotation of a solution
Authors: Xu Yang , Shi Lixuan , Guan Tian , Zhong Suyi , Zhou Xuesi , Li Dongmei , Guo Cuixia , Yang Yuxuan , Wang Xiangnan , Li Zhangyan , He Yonghong , Xie Luyuan , Gan Zonghan
Published: May 2019

In this study, we propose a multifunctional weak measurement system that can measure the optical rotation and the refractive index of solution. The center wavelength of the output spectrum of such a system is sensitive to the optical rotation and the phase difference produced by total internal reflection. The optical resolution and refractive index resolution of the solution determined by the proposed method were 3.26 × 10–5° and 3.93 × 10–7 RIU, respectively, by measuring different concentrations of glucose solution. As the optical rotation and refractive index of the solution are important properties of the solution, this system can be used to determine the type of solute in the solution in the future.
Filament flexibility enhances power transduction of F-actin bundles
Authors: Perilli Alessia , Pierleoni Carlo , Ryckaert Jean-Paul
Published: May 2019

The dynamic behavior of bundles of actin filaments growing against a loaded obstacle is investigated through a generalized version of the standard multifilament Brownian Ratchet model in which the (de)polymerizing filaments are treated not as rigid rods but as semiflexible discrete wormlike chains with a realistic value of the persistence length. By stochastic dynamic simulations, we study the relaxation of a bundle of Nf filaments with a staggered seed arrangement against a harmonic trap load in supercritical conditions. Thanks to the time scale separation between the wall motion and the filament size relaxation, mimicking realistic conditions, this setup allows us to extract a full load-velocity curve from a single experiment over the trap force/size range explored. We observe a systematic evolution of steady nonequilibrium states over three regimes of bundle lengths L. A first threshold length Λ marks the transition between the rigid dynamic regime (L < Λ), characterized by the usual rigid filament load-velocity relationship V(F), and the flexible dynamic regime (L > Λ), where the velocity V(F, L) is an increasing function of the bundle length L at a fixed load F, the enhancement being the result of an improved level of work sharing among the filaments induced by flexibility. A second critical length corresponds to the beginning of an unstable regime characterized by a high probability to develop escaping filaments which start growing laterally and thus do not participate anymore in the generation of the polymerization force. This phenomenon prevents the bundle from reaching at this critical length the limit behavior corresponding to perfect load sharing.
Numerical investigation on the dynamics of aluminum wire explosions
Authors: Shi Yuanjie , Shi Zongqian , Wang Kun , Ren Zheng
Published: May 2019

Explosions of aluminum wires driven by a negative fast rising current (∼80 A/ns) are numerically investigated by using a magnetohydrodynamic code with cold start conditions. A wide range of semi-empirical equations of state based on the Thomas–Fermi–Kirzhnits model and a modified Lee–More–Desjarlais conductivity model are used to model the behavior of the exploding product. The formation and the evolution of the core–corona structure are presented. The corona reaches a maximum temperature of ∼100 eV after the voltage breakdown and expands at a constant speed of 39 km/s. The influence of the wire diameter on the characteristics of the explosion is studied, which shows the maximum energy deposition of 2.6 eV/atom at a wire diameter of 18.4 μm. The simulation is compared with the previous experimental result and shows good agreement.
Wavefront detection using curved nanoscale apertures
Authors: Pelzman Charles , Cho Sang-Yeon
Published: May 2019

In this paper, we report the experimental demonstration of wavefront sensing using curved subwavelength apertures. The demonstrated subwavelength structure has an ability to convert the shape of an incident wavefront into a two-dimensional array of focused surface plasmon (SP) waves. The detection principle is based on the phase-dependent spatial displacement of the focal point in circular apertures. The unit-cell structure of the demonstrated device consists of a circular disk surrounded by subwavelength concentric rings to excite highly enhanced SP waves at a designed wavelength. The excited surface waves, carrying the wavefront information of the incident beam, constructively interfere with each other and can be focused inside the disk. For demonstration, a 3-by-3 concentric-ring aperture array was fabricated and experimentally characterized. The focused SP waves within each of the fabricated 3-by-3 apertures under an optical excitation beam with a concave wavefront move toward the center of the array. When the shape of the incident wavefront was changed to convex, the focused spots in the array move away from the center. By measuring the spatial displacement of the focused spot, the shape of the incident wavefront can be directly measured. The demonstrated approach does not require complicated 3-D integration or optical alignment and offers a very high spatial resolution in wavefront detection, and thus, it has great potential for revolutionizing existing wavefront sensors.
System of ideal quantum dots with Coulomb interaction
Authors: Mandel A.M. , Oshurko V.B. , Pershin S.M.
Published: May 2019

The wave functions of single-electron states localised on a system of single-level ideal quantum dots in a semiconductor matrix are constructed. The standard Kane theory, which describes the renormalisation of the effective mass of electrons in bulk III − V semiconductors, is transformed, for the first time as far as we know, for small-size quantum dots. The renormalised electron mass in a quantum dot depends on its ground state energy, which, in turn, depends on this mass. Thus, a self-consistent problem is obtained for calculating the electron binding energy. The radius of the Debye screening of the Coulomb interaction in a system of quantum dots is calculated at room temperature. The Coulomb repulsion of electrons localised on dots limits from above the possible number of filled dots. The condition is formulated for the optimal concentration of quantum dots. A classical distribution function for the probability of quantum dot filling is constructed. It is found the state, where electrons fill exactly half the maximum possible number of filled dots, exhibits the minimal energy (and therefore the most stable), the condition being fairly universal. In particular, it can be used to estimate the limiting efficiency of quantum-dot diode lasers.
Modelling of polarised optical frequency domain reflectometry of axially twisted anisotropic optical fibres
Authors: Barkov F.L. , Konstantinov Yu.A. , Bochkova S. D. , Smirnov A.S. , Burdin V.V. , Krivosheev A.I. , Nosova E.A. , Smetannikov O.Yu.
Published: May 2019

This paper presents a mathematical model that describes the influence of defects in an anisotropic optical fibre on its polarised frequency domain reflectograms. The model relies on the Jones matrix formalism. Calculated reflectograms are presented for a uniform axial twist of an optical fibre. As input data for simulation, we use real distributed optical parameters of the fibre determined by polarised light Brillouin reflectometry.
Modelling of output mirrors based on circular gradient structures for THz lasers
Authors: Dzyubenko M.I. , Maslov V.A. , Odarenko E.N. , Radionov V.P.
Published: May 2019

We substantiate the use of gradient periodic structures placed on a plane substrate and consisting of concentric metal rings with parameters varying in radial direction, as output mirrors for THz lasers. Using computer simulation, it is shown that, with a certain change in parameters, such a structure has the properties of a concave mirror and a focusing lens, which is of importance for output mirrors of THz lasers.
Tunable laser based on a semiconductor optical amplifier of red spectral region
Authors: Andreeva E.V. , Anikeev A.S. , Il’chenko S.N. , Lobintsov A.A. , Chamorovskii A.Yu. , Shidlovskii V.R. , Shramenko M.V. , Yakubovich S.D.
Published: May 2019

A tunable laser containing a recently developed travelling wave semiconductor optical amplifier (SOA) of the red spectral region as an active element and an acousto-optic tunable filter in an external fibre ring cavity is studied. Continuous wavelength tuning was achieved within a spectra band up to 20 nm wide with a rate up to 104 nm s−1 at a spectral linewidth below 0.04 nm and a cw output power up to 2 mW. The use of one more similar SOA as an output power amplifier made it possible to increase the output power to 15 mW.
Investigation of the possibility of ultra-deep laser cooling using a quadrupole transition
Authors: Kirpichnikova A.A. , Prudnikov O.N. , Wilkowski D.
Published: May 2019

We consider the kinetics of atoms in nonuniform spatially polarised light fields resonant to the quadrupole optical transition with F
g → F
e = F
g + 2 (F
g,e is the total angular momentum in the ground and excited states). The lowest possible temperatures of laser cooling of atoms are analysed numerically and the results are compared with the data obtained for sub-Doppler cooling using light waves resonant to electric dipole optical transitions.
Scheme of a hydrogen-molecule quantum simulator based on two ultracold rubidium atoms
Authors: Ashkarin I.N. , Beterov I.I. , Tretyakov D.B. , Entin V.M. , Yakshina E.A. , Ryabtsev I.I.
Published: May 2019

A scheme is proposed for implementing a hydrogen-molecule quantum simulator based on two ultracold rubidium atoms trapped into spatially separated optical dipole traps. The scheme includes the adiabatic preparation of the initial quantum state of two atoms and the iterative quantum phase estimation. The accuracy of measuring the ground state energy of a molecule is numerically calculated as a function of the number of iterations. The simulation is performed using two-qubit gates based on the dipole blockade effect under short-term excitation of atoms into the Rydberg states with allowance for the finite lifetime of Rydberg states and the finite energies of the van der Waals interaction.
Effect of trapped-ion heating on generalised Ramsey methods for suppressing frequency shifts caused by a probe field in atomic clocks
Authors: Kuznetsov S.N. , Taichenachev A.V. , Yudin V.I. , Hunteman N. , Sanner K. , Tamm K. , Peik E.
Published: May 2019

Based on a simple one-dimensional model, we consider the effect of trapped-ion heating on the efficiency of generalised Ramsey methods for the probe-induced frequency shift suppression in optical frequency standards based on single ultracold ions. It is shown that ion heating reduces the efficiency of all previously proposed one-loop generalised Ramsey methods, leading in all cases to the appearance of a linear dependence of the reference frequency shift on the residual field frequency shift. Two versions of the most heating stable generalised Ramsey schemes, for which the proportionality coefficient in this dependence is minimal, are demonstrated.
Squid, the Vibrio and the Moon
Authors: Wild Ailsa , Reed Aviva , Barr Briony , Crocetti Gregory , Blackall Linda
Published: May 2019

When he hatches from his egg, Sepio, a baby bobtail squid, is not able to glow. His dark shape is too obvious in the moonlit water and all kinds of predators lurk nearby. Ali, an intrepid Vibrio fischeri bacterium, is determined to reach safety too.
Can Ali and Sepio help each other?
The Squid, the Vibrio and the Moon is a beautifully illustrated storybook about the symbiotic relationship between the Hawaiian bobtail squid and the bioluminescent bacteria that help it glow in the moonlight.
Originally published in 2014, this book has been extensively re-written to delight and captivate primary-school aged readers.
Of a different feather: two new species of featherheads from the
Authors: Hammer Timothy A. , Davis Robert W. , Thiele Kevin R.
Published: May 2019

Ptilotus macrocephalus (R.Br.) Poir. (Amaranthaceae), commonly known as a featherhead, is a widespread and common species in many parts of Australia. In the present study, we assess morphological variation in P. macrocephalus throughout its geographic range and provide evidence for the recognition of two new species, namely, P. psilorhachis T.Hammer & R.W.Davis and P. xerophilus T.Hammer & R.W.Davis. Geospatial analyses indicated that these new species are partitioned ecologically and geographically.
Interspecific divergence in biological attributes of short-tailed pythons (Python breitensteini and P. brongersmai) from Kalimantan and Sumatra
Authors: Natusch Daniel J. D. , Lyons Jessica A. , Riyanto Awal , Mumpuni  , Shine Richard
Published: May 2019

Short-tailed pythons (Python breitensteini, P. brongersmai and P. curtus) are exploited in large numbers for the international leather trade, but their ecology remains poorly known. We quantify sexual dimorphism and reproductive output in P. breitensteini from Kalimantan and P. brongersmai from sites in north and south Sumatra. Sexual dimorphism was more evident in P. breitensteini (males less heavy-bodied than females, and with longer heads relative to body length) than in either population of P. brongersmai. Although having a smaller average adult body size, P. breitensteini had a larger clutch size (mean of 17.2 eggs, versus 12.6 and 14.5 in the two brongersmai populations), and a higher reproductive frequency (92% of adult-size females reproductive, versus 38 and 50%). Female pythons from Kalimantan laid their eggs in September through November whereas female P. brongersmai from north Sumatra oviposited from March to May, in keeping with their geographic position either side of the equator. Paradoxically, however, P. brongersmai from south Sumatra apparently lay eggs at the same time as their northern conspecifics, despite their latitudinal position corresponding to our P. breitensteini study site. Reproductive traits within tropical snakes may be more diverse than is currently understood, even within clades of closely related taxa.
A survey of computational frameworks for solving the acoustic inverse problem in three-dimensional photoacoustic computed tomography
Authors: Poudel Joemini , Lou Yang , Anastasio Mark A
Published: May 2019

Photoacoustic computed tomography (PACT), also known as optoacoustic tomography, is an emerging imaging technique that holds great promise for biomedical imaging. PACT is a hybrid imaging method that can exploit the strong endogenous contrast of optical methods along with the high spatial resolution of ultrasound methods. In its canonical form that is addressed in this article, PACT seeks to estimate the photoacoustically-induced initial pressure distribution within the object. Image reconstruction methods are employed to solve the acoustic inverse problem associated with the image formation process. When an idealized imaging scenario is considered, analytic solutions to the PACT inverse problem are available; however, in practice, numerous challenges exist that are more readily addressed within an optimization-based, or iterative, image reconstruction framework. In this article, the PACT image reconstruction problem is reviewed within the context of modern optimization-based image reconstruction methodologies. Imaging models that relate the measured photoacoustic wavefields to the sought-after object function are described in their continuous and discrete forms. The basic principles of optimization-based image reconstruction from discrete PACT measurement data are presented, which includes a review of methods for modeling the PACT measurement system response and other important physical factors. Non-conventional formulations of the PACT image reconstruction problem, in which acoustic parameters of the medium are concurrently estimated along with the PACT image, are also introduced and reviewed.
On a Linnik problem for elliptic curves
Authors: Dąbrowski Andrzej , Pomykała Jacek
Published: May 2019

Let

S
(
Q
,
B
)

S(Q,B)

denote the number of moduli

q
≤
Q

q\leq Q

for which a primitive character

χ
\chi

mod

q
q

exists such that

n

χ

>
B

n_{\chi }>B

, where

n

χ

n_{\chi }

denotes the smallest natural number such that

χ
(
n
)
≠
1

\chi (n) \not =1

. Baier showed that for any

β
>
2

\beta >2

we have

S
(
Q
,
(
log
⁡
Q

)

β

)
≪

Q

1

β
−
1

+
ε

S(Q,(\log Q)^{\beta }) \ll Q^{\frac {1}{\beta -1}+\varepsilon }

and asked for an analogue of this result for elliptic curves. It is the aim of this note to establish such an analogue.
Chromokinesin Kif4 promotes proper anaphase in mouse oocyte meiosis
Authors: Heath Carissa M. , Wignall Sarah M.
Published: May 2019

Oocytes of many species lack centrioles and therefore form acentriolar spindles. Despite the necessity of oocyte meiosis for successful reproduction, how these spindles mediate accurate chromosome segregation is poorly understood. We have gained insight into this process through studies of the kinesin-4 family member Kif4 in mouse oocytes. We found that Kif4 localizes to chromosomes through metaphase and then largely redistributes to the spindle midzone during anaphase, transitioning from stretches along microtubules to distinct ring-like structures; these structures then appear to fuse together by telophase. Kif4’s binding partner PRC1 and MgcRacGAP, a component of the centralspindlin complex, have a similar localization pattern, demonstrating dynamic spindle midzone organization in oocytes. Kif4 knockdown results in defective midzone formation and longer spindles, revealing new anaphase roles for Kif4 in mouse oocytes. Moreover, inhibition of Aurora B/C kinases results in Kif4 mislocalization and causes anaphase defects. Taken together, our work reveals essential roles for Kif4 during the meiotic divisions, furthering our understanding of mechanisms promoting accurate chromosome segregation in acentriolar oocytes.
Domain-specific mechanical modulation of VWF–ADAMTS13 interaction
Authors: Li Zhenhai , Lin Jiangguo , Sulchek Todd , Cruz Miguel A. , Wu Jianhua , Dong Jing-fei , Zhu Cheng
Published: May 2019

Hemodynamic forces activate the Von Willebrand factor (VWF) and facilitate its cleavage by a disintegrin and metalloprotease with thrombospondin motifs-13 (ADAMTS13), reducing the adhesive activity of VWF. Biochemical assays have mapped the binding sites on both molecules. However, these assays require incubation of two molecules for a period beyond the time allowed in flowing blood. We used a single-molecule technique to examine these rapid, transient, and mechanically modulated molecular interactions in short times under forces to mimic what happens in circulation. Wild-type ADAMTS13 and two truncation variants that either lacked the C-terminal thrombospondin motif-7 to the CUB domain (MP-TSP6) or contained only the two CUB domains (CUB) were characterized for interactions with coiled VWF, flow-elongated VWF, and a VWF A1A2A3 tridomain. These interactions exhibited distinctive patterns of calcium dependency, binding affinity, and force-regulated lifetime. The results suggest that 1) ADAMTS13 binds coiled VWF primarily through CUB in a calcium-dependent manner via a site(s) outside A1A2A3, 2) ADAMTS13 binds flow-extended VWF predominantly through MP-TSP6 via a site(s) different from the one(s) at A1A2A3; and 3) ADAMTS13 binds A1A2A3 through MP-TSP6 in a Ca2+-dependent manner to autoinhibit another Ca2+-independent binding site on CUB. These data reveal that multiple sites on both molecules are involved in mechanically modulated VWF–ADAMTS13 interaction.
Force balances between interphase centrosomes as revealed by laser ablation
Authors: Odell Jacob , Sikirzhytski Vitali , Tikhonenko Irina , Cobani Sonila , Khodjakov Alexey , Koonce Michael
Published: May 2019

Numerous studies have highlighted the self-centering activities of individual microtubule (MT) arrays in animal cells, but relatively few works address the behavior of multiple arrays that coexist in a common cytoplasm. In multinucleated Dictyostelium discoideum cells, each centrosome organizes a radial MT network, and these networks remain separate from one another. This feature offers an opportunity to reveal the mechanism(s) responsible for the positioning of multiple centrosomes. Using a laser microbeam to eliminate one of the two centrosomes in binucleate cells, we show that the unaltered array is rapidly repositioned at the cell center. This result demonstrates that each MT array is constantly subject to centering forces and infers a mechanism to balance the positions of multiple arrays. Our results address the limited actions of three kinesins and a cross-linking MAP that are known to have effects in maintaining MT organization and suggest a simple means used to keep the arrays separated.
Sexual dimorphism of niche architecture and regulation of theCaenorhabditis elegansgermline stem cell pool
Authors: Crittenden Sarah L. , Lee ChangHwan , Mohanty Ipsita , Battula Sindhu , Knobel Karla , Kimble Judith
Published: May 2019

Stem cell maintenance by niche signaling is a common theme across phylogeny. In the Caenorhabditis elegans gonad, the broad outlines of germline stem cell (GSC) regulation are the same for both sexes: GLP-1/Notch signaling from the mesenchymal distal tip cell niche maintains GSCs in the distal gonad of both sexes and does so via two key stem cell regulators, SYGL-1 and LST-1. Yet most recent analyses of niche signaling and GSC regulation have focused on XX hermaphrodites, an essentially female sex making sperm in larvae and oocytes in adults. Here we focus on GSC regulation in XO males. Sexual dimorphism of niche architecture, reported previously, suggested that the molecular responses to niche signaling or numbers of GSCs might also be sexually distinct. Remarkably, this is not the case. This work extends our understanding of the sexually dimorphic niche architecture, but also demonstrates that the dimorphic niches drive a similar molecular response and maintain a similar number of GSCs in their stem cell pools.
Peaks, Means, and Determinants of Real-Time TVOC Exposures Associated with Cleaning and Disinfecting Tasks in Healthcare Settings
Authors: Virji M Abbas , Liang Xiaoming , Su Feng-Chiao , LeBouf Ryan F , Stefaniak Aleksandr B , Stanton Marcia L , Henneberger Paul K , Houseman E Andres
Published: May 2019

Cleaning and disinfecting tasks and product use are associated with elevated prevalence of asthma and respiratory symptoms among healthcare workers; however, the levels of exposure that pose a health risk remain unclear. The objective of this study was to estimate the peak, average, and determinants of real-time total volatile organic compound (TVOC) exposure associated with cleaning tasks and product-use. TVOC exposures were measured using monitors equipped with a photoionization detector (PID). A simple correction factor was applied to the real-time measurements, calculated as a ratio of the full-shift average TVOC concentrations from a time-integrated canister and the PID sample, for each sample pair. During sampling, auxiliary information, e.g. tasks, products used, engineering controls, was recorded on standardized data collection forms at 5-min intervals. Five-minute averaged air measurements (n = 10 276) from 129 time-series comprising 92 workers and four hospitals were used to model the determinants of exposures. The statistical model simultaneously accounted for censored data and non-stationary autocorrelation and was fit using Markov-Chain Monte Carlo within a Bayesian context. Log-transformed corrected concentrations (cTVOC) were modeled, with the fixed-effects of tasks and covariates, that were systematically gathered during sampling, and random effect of person-day. The model-predicted geometric mean (GM) cTVOC concentrations ranged from 387 parts per billion (ppb) for the task of using a product containing formaldehyde in laboratories to 2091 ppb for the task of using skin wipes containing quaternary ammonium compounds, with a GM of 925 ppb when no products were used. Peak exposures quantified as the 95th percentile of 15-min averages for these tasks ranged from 3172 to 17 360 ppb. Peak and GM task exposures varied by occupation and hospital unit. In the multiple regression model, use of sprays was associated with increasing exposures, while presence of local exhaust ventilation, large room volume, and automatic sterilizer use were associated with decreasing exposures. A detailed understanding of factors affecting TVOC exposure can inform targeted interventions to reduce exposures and can be used in epidemiologic studies as metrics of short-duration peak exposures.
Bile salt hydrolase can improve Lactobacillus plantarum survival in gastrointestinal tract by enhancing their adhesion ability
Authors: Yang Yao , Liu Yanrong , Zhou Sisi , Huang Lu , Chen Ying , Huan Hailin
Published: May 2019

Lactic acid bacteria (LAB) are major probiotics in food supplements. Survival in gastrointestinal (GI) tract is important for the effective use of LAB as probiotics. Bile salt hydrolase (BSH), which catalyzes the conversion of conjugated bile salts into free bile salts, can significantly modulate the gut microbiome. Here, we hypothesize that BSH is important for LAB survival and adhesion in the gut. The aim of this study is to investigate the effect of BSH on the survival of LAB in the GI tract. A panel of bsh genes from murine gut microbiota were amplified, cloned and expressed into Lactobacillus plantarum, which were then administered to mice by gavage. Our data indicated that the survival of BSH-positive L. plantarum was significantly prolonged in the GI tract compared with wild type L. plantarum. Furthermore, BSH-positive strains exhibited increased adhesion to Caco-2 intestinal cells than BSH-deleted L. plantarum. Enhanced adhesion to intestinal cells of BSH positive LAB can therefore be an important criterion for selecting effective probiotic strains in food industry.
Structural and Compositional Responses to Thinning over 50 Years in Moist Forest of the Northern Rocky Mountains
Authors: Shen Chenchen , Nelson Andrew S , Jain Terrie B , Foard Meghan B , Graham Russell T
Published: May 2019

A thinning study was established in 1967 in moist mixed forests on the Priest River Experimental Forest in northern Idaho, USA. The study design included three thinning intensities: low, moderate, and high intensity (1,976, 988, and 494 trees ha–1). This study examined short-term (11 years) and long-term (50 years) thinning effects on residual stand characteristics, growth, and yield. Since regeneration may occur after thinning, understory change was also addressed. Thinning decreased stand density immediately but improved the growth of residual trees. Shade-tolerant species were favored in all the thinnings and dominated 50 years after thinning. Unthinned stands had higher total and merchantable volume than all thinned stands both 11 years and 50 years post treatment. Regeneration and nontree vegetation richness increased shortly after thinning, whereas nontree vegetation cover decreased sharply 50 years after treatment. The stands developed into multistrata forests with shade-tolerant species in both the overstory and understory. This is contrary to current thinning practice favoring shade-intolerant species, but demonstrates the resilience of moist Northern Rockies forests to partial overstory disturbances. In this study, thinning favoring shade-tolerant species in these mixed forests has a more significant effect on forest structure dynamics than timber production.
Basic principles for the design of antitrust analysis for multisided platforms
Authors: Evans David S
Published: May 2019

This article presents some basic principles for conducting the antitrust analysis of multisided platforms that courts could adapt to the particulars of their jurisdictions and case laws. It has a particular focus on measuring consumer surplus for platform businesses and the implications of that for the design of antitrust rules. It shows how multisided platforms increase welfare by reducing transactions costs and resolving externalities among economic agents. It presents three normative principles for policy interventions and illustrates these principles by showing how they apply to recent debates over privacy. The article then develops a framework for considering antitrust rules in light of these principles given the objectives of antitrust law, error costs, and developing administrable rules. It lastly considers the competing approaches to analysing multisided platforms that were presented to the Supreme Court in the American Express litigation and the Court’s decision in light of these principles.