bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of the hepatotoxic potential of Tinospora crispa and its isolated borapetosides B, C and F in a murine model
Authors: Parveen Abidah , Maqbool Mir Tahir , Wang Yan-Hong , Ali Zulfiqar , Khan Ikhlas A. , Ashfaq M. Khalid
Published: March 2020

The hepatotoxic potential of the methanolic extract of the stems of Tinospora crispa and of its furano-diterpenoid–borapetosides B, C, and F–was investigated in normal and health-compromised mice. Health-compromised condition was established by a single intraperitoneal injection of LPS (6 mg/kg). Two different sets of experiments were conducted to evaluate the hepatotoxic potential. A 21-day study where the mice were dosed with the extract of T. crispa (1 gm/kg b. wt./day) or standardized combination of borapetosides B, C and F (500 mg/kg b. wt.) with or without a single dose of LPS (1 gm/kg b. wt./day). In the acute toxicity study, mice were dosed with borapetosides B, C, and F (500 mg/kg b. wt.). Results showed that the ALT levels were normal and liver histopathology unaltered. No conclusive hepatotoxicity was observed in the methanolic extract or pure compounds tested under the given experimental conditions.
Salvage-Lymphadenektomie des lymphogenen Prostatakarzinomrezidivs
Authors: Stolzenbach Lara Franziska , Knipper Sophie , Maurer Tobias
Published: March 2020

Das lymphogene Prostatakarzinomrezidiv kann seit der Einführung funktioneller Bildgebung wie der PSMA PET/CT oft frühzeitig diagnostiziert werden. Aktuelle Studien zur lokalen Behandlung der Lymphknotenmetastasen legen einen positiven Einfluss auf die Prognose bei ausgewählten Patienten nahe. Dennoch ist die Mehrzahl der Studien retrospektiv und aus Mangel an höhergradiger Evidenz gilt die Salvage-Lymphadenektomie (LA) als nicht-leitlinienkonform.

Ziel dieser Arbeit ist die kritische Zusammenfassung der aktuellen Datenlage zur Salvage-LA des lymphogenen Prostatakarzinomrezidivs mit dem Fokus auf die bildgebenden Verfahren, die Ausdehnung der LA und den onkologischen Verlauf.

Die europäischen Leitlinien empfehlen die Durchführung der Cholin- oder PSMA PET/CT-Bildgebung bei einem Verdacht auf ein Prostatakarzinomrezidiv. Die PSMA-PET/CT ist der Cholin-PET/CT in Sensitivität und Spezifität überlegen und sollte dabei favorisiert werden.

Wird eine Salvage-LA dennoch durchgeführt, ist die gängige Praxis eine bilaterale LA – auch bei einem im PSMA-PET/CT nachgewiesenen einseitigen Lymphknotenbefall. Allerdings kann ebenfalls die unilaterale LA in Erwägung gezogen werden. Eine aktuell eingeleitete randomisierte prospektive Studie (ProSTone) soll diese Fragestellung beantworten.

Ein neuer vielversprechender chirurgischer Ansatz scheint die PSMA-radioguided surgery zu sein. Sie erleichtert das intraoperative Auffinden von Lymphknotenmetastasen. Langzeitdaten sind aber noch abzuwarten.

Insgesamt erreicht die Salvage-LA bei sorgfältig ausgewählten Patienten eine respektable biochemische Ansprechrate. Dennoch sind für die Zukunft prospektive Studien notwendig, um den Stellenwert genauer definieren zu können.
Primary Aldosteronism and Obstructive Sleep Apnea: Casual Association or Pathophysiological Link?
Authors: Pecori Alessio , Buffolo Fabrizio , Pieroni Jacopo , Forestiero Vittorio , Sconfienza Elisa , Veglio Franco , Mulatero Paolo , Monticone Silvia
Published: March 2020

The coexistence of aldosterone oversecretion and obstructive sleep apnea is frequently observed, especially in patients with resistant hypertension, obesity, and metabolic syndrome. Since aldosterone excess and sleep apnea are both independently associated with an increased risk of cardiovascular disease, to investigate whether their coexistence might be attributed to common predisposing conditions, such as metabolic disorders, or to an actual pathophysiological interconnection appears of great importance. Fluid overload and metabolic abnormalities relating to aldosterone oversecretion may be implicated in obstructive sleep apnea development. Nocturnal intermittent hypoxia may in turn exacerbate renin-angiotensin-aldosterone system activity, thus leading to hyperaldosteronism. Furthermore, fat tissue excess and adipocyte secretory products might predispose to both sleep apnea and aldosterone oversecretion in subjects with obesity. Consistent with these evidences, obstructive sleep apnea frequently affects patients with primary aldosteronism. Conversely, whether primary aldosteronism is more prevalent in individuals affected by obstructive sleep apnea compared to the general population remains controversial.
Effects of ACE Inhibitors and Angiotensin Receptor Blockers in
Normotensive Patients with Diabetic Kidney Disease
Authors: He Dandan , Zhang Yaru , Zhang Wei , Xing Yue , Guo Yipeng , Wang Fuzhen , Jia Junya , Yan Tiekun , Liu Youxia , Lin Shan
Published: March 2020

The role of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin
receptor blockers (ARBs) in reducing the progression of albuminuria and risk of
cardiovascular events in hypertensive patients with diabetic kidney disease
(DKD) is well-documented. However, the efficacy and safety of these agents in
normotensive patients with DKD are still controversial. MEDLINE, Embase, and
Cochrane Library were searched for relevant random controlled trials. The odd
risk (OR) reductions were calculated with a random-effects model. Decrease in
albuminuria, changes in eGFR, major cardiovascular events, and drug-related
adverse events were analyzed. Thirteen RCTs including 1282 patients were
retrieved. Compared with placebo or other active agent groups, ACEIs or ARBs
significantly decreased albuminuria (MD –80.28 mg/d,
95% CI –104.79 mg/d to
–55.77 mg/d), and the efficacy is independent of changes
in blood pressure and systolic blood pressure at baseline. The result of
subanalysis showed the declining of albuminuria was more significantly in
normotensive DKD patients with 2DM (p=0.005). No significant differences
were found with regard to the declining of evaluated glomerular filtration rate
(eGFR) (MD
–0.29 ml/min/1.73 m2,
95% CI –2.99 to
2.41 ml/min/1.73 m2). There were
no significant differences in the side effect of the drugs such as hypotension
and hyperkalemia. This meta-analysis demonstrated that ACEIs or ARBs can
decrease albuminuria to varying degree in normotensive patients with DKD, and
better response occurred in patients with 2DM.
Accessing Polycyclic Terpenoids from Zerumbone via Lewis Acid Catalyzed Synthetic Strategies
Authors: Sharathna Puthiyaparambath , Meenu Murugan Thulasi , Radhakrishnan Kokkuvayil Vasu , Dhanya Bhandara Purayil , Gopalan Greeshma , Sasikumar Parameswaran , Krishnan Radhakrishnan Syam
Published: March 2020

We herein disclose an effective strategy for the synthesis of [5.3.0] and [6.3.0] fused polycyclic terpenoids, which are important structural elements of natural products and biologically active compounds. The method comprises of Lewis acid catalyzed interrupted Nazarov cyclization of zerumbone derivatives such as zerumbone epoxide, triazole-appended zerumbone, zerumbal, and zerumbenone with a wide substrate scope with different indoles. Zerumbone epoxide furnished [5.3.0] and [6.3.0] fused structurally diverse sesquiterpenoids and all other zerumbone derivatives furnished the [6.3.0] fused motifs.
Large enhancement of thermoelectric effect by Majorana bound states coupled to a quantum dot
Authors: Hong Lan , Chi Feng , Fu Zhen-Guo , Hou Yue-Fei , Wang Zhigang , Li Ke-Man , Liu Jia , Yao Haiyan , Zhang Ping
Published: March 2020

This paper presents a theoretical study of the thermoelectric effect in a quantum dot (QD) side-coupled to Majorana bound states (MBSs) formed at the two ends of a Rashba nanowire. In the low-temperature regime favorable for the preparation of MBSs, the magnitude of the thermopower and figure of merit (FOM) are both enhanced by two or three orders of magnitude upon optimizing the QD-MBS coupling strength. In addition, the sign of the thermopower can be reversed by changing the QD-MBS coupling strength, a phenomenon that may be useful for detecting MBSs. The direct overlap between the MBSs also changes the sign of the thermopower and suppresses the magnitude of the FOM at low temperature. However, such an overlap has little influence on the thermopower and FOM at high temperature. In the presence of Zeeman splitting in the QD, the peaks corresponding to spin-up and spin-down thermopowers shift in opposite directions in the QD energy-level space, resulting in a large 100% spin polarization and pure spin thermopower that is crucial in spin caloritronics. Finally, the spin (charge) FOMs are enhanced (reduced) by increasing the Zeeman splitting.
ASNOM mapping of SiC epilayer doping profile and of surface phonon polariton waveguiding
Authors: Kazantsev D. , Ryssel Heiner
Published: March 2020

Apertureless scanning near-field optical microscopy mapping of a slightly doped 4H-SiC epitaxial layer grown on a heavily doped 4H-SiC substrate was performed in a cleaved edge geometry. Surface phonon polariton waves excited by an external coherent light were observed on a sample surface that contains such an epilayer-defined strip near its edge. The light frequency was tuned close to the lattice resonance. Due to a low doping level in an epilayer, its electromagnetic response is determined mainly by the SiC lattice resonance. The rest of the sample surface corresponds to a substrate whose electromagnetic response is determined mainly by the free carriers so that phonon polariton phenomena get suppressed. Such an epilayer-defined strip (vanishing at 895cm−1 frequency) becomes more pronounced at 920cm−1 and, finally, the excited state gets completely confined within such a strip (938cm−1) due to the differences in the electromagnetic properties of doped and undoped SiC.
Measurement optimization in the variational quantum eigensolver using a minimum clique cover
Authors: Verteletskyi Vladyslav , Yen Tzu-Ching , Izmaylov Artur F.
Published: March 2020

Solving the electronic structure problem using the Variational Quantum Eigensolver (VQE) technique involves the measurement of the Hamiltonian expectation value. The current hardware can perform only projective single-qubit measurements, and thus, the Hamiltonian expectation value is obtained by measuring parts of the Hamiltonian rather than the full Hamiltonian. This restriction makes the measurement process inefficient because the number of terms in the Hamiltonian grows as O(N4) with the size of the system, N. To optimize the VQE measurement, one can try to group as many Hamiltonian terms as possible for their simultaneous measurement. Single-qubit measurements allow one to group only the terms commuting within the corresponding single-qubit subspaces or qubit-wise commuting. We found that the qubit-wise commutativity between the Hamiltonian terms can be expressed as a graph and the problem of the optimal grouping is equivalent to finding a minimum clique cover (MCC) for the Hamiltonian graph. The MCC problem is NP-hard, but there exist several polynomial heuristic algorithms to solve it approximately. Several of these heuristics were tested in this work for a set of molecular electronic Hamiltonians. On average, grouping qubit-wise commuting terms reduced the number of operators to measure three times less compared to the total number of terms in the considered Hamiltonians.
Temperature expansions in the square-shoulder fluid. I. The Wiener–Hopf function
Authors: Coquand O. , Sperl M.
Published: March 2020

We investigate the spatial structure of dense square-shoulder fluids. To this end, we derive analytical perturbative solutions of the Ornstein–Zernike equation in the low- and high-temperature limits as expansions around the known hard sphere solutions. We then discuss the suitability of perturbative approaches in relation to the Ornstein–Zernike equation. Our analytical expressions are shown to reproduce reasonably well numerical data in the appropriate regimes.
Temperature expansions in the square-shoulder fluid. II. Thermodynamics
Authors: Coquand O. , Sperl M.
Published: March 2020

In Paper I [O. Coquand and M. Sperl, J. Chem. Phys. 152, 124112 (2020)], we derived analytical expressions for the structure factor of the square-shoulder potential in a perturbative way around the high- and low-temperature regimes. Here, various physical properties of these solutions are derived. In particular, we investigate the large wave number sector and relate it to the contact values of the pair-correlation function. Then, the thermoelastic properties of the square-shoulder fluids are discussed.
Improved theoretical calculations for electron-impact ionization of DNA analogue molecules
Authors: Ali Esam , Chakraborty H. S. , Madison D. H.
Published: March 2020

Ionizing interactions between charged particles and molecules of biological relevance have attracted considerable interest in the last decade due to its importance in medical radiation therapy. We have previously calculated triply differential cross sections for five biomolecules in collaboration with experimental groups. We used the molecular 3-body distorted wave approximation for these calculations. For ionization of biomolecules, experimentalists are unable to determine the orientation of the molecule at the time of ionization, which means that the calculated cross sections need to be averaged over all molecular orientations. At the time the calculations were performed, it was not numerically feasible for us to perform proper averaging over orientations, so we introduced the orientation averaged molecular orbital approximation to make the calculations possible. We now have the computational capability to properly perform this average, so, here, we present new results with a proper average over orientations and compare with the previous calculations and experiment. Since the original calculations, results from two different distorted-wave models have also been published and the new results will also be compared with those calculations. Overall, the new results are in better agreement with the experiment.
Energy dissipation analysis based on velocity gradient tensor decomposition
Authors: Wu Yifei , Zhang Weihao , Wang Yufan , Zou Zhengping , Chen Jiang
Published: March 2020

A velocity gradient tensor decomposition method based on a normal frame is introduced in this paper. The velocity gradient tensor is decomposed into a compression–stretching tensor, pure rotation tensor, and pure shear tensor. The analysis shows that both the strain rate tensor and vorticity tensor in Helmholtz velocity decomposition contain shear tensor components, and the total pure shear tensor is the combination of shear components in the two tensors. Based on this decomposition and the physical meaning of each tensor term, the energy dissipation of the channel flow with or without a pressure gradient and a turbine passage flow are analyzed. The results show that the energy dissipation is caused by shear deformation and expansion and contraction deformation of the motion fluid, and pure rotation does not cause energy dissipation. In particular, the pure shear is the primary factor of energy dissipation. Shear accounts for 99.9% of energy dissipation in the fully developed turbulence of zero-pressure gradient channel flow, 99% of the energy dissipation in the separated boundary layer flow is caused by the pure shear, and 81% of the energy dissipation in the turbine stage flow is caused by pure shear.
Tuning martensitic transformations via coherent second phases in nanolaminates using free energy landscape engineering
Authors: Desai Saaketh , Reeve Samuel Temple , Vishnu Karthik Guda , Strachan Alejandro
Published: March 2020

We explore the possibilities and limitations of using a coherent second phase to engineer the thermo-mechanical properties of a martensitic alloy by modifying the underlying free energy landscape that controls the transformation. We use molecular dynamics simulations of a model atomistic system where the properties of a coherent, nanoscale second phase can be varied systematically. With a base martensitic material that undergoes a temperature-induced transformation from a cubic austenite to a monoclinic martensite, simulations show significant ability to engineer the transformation temperatures, from a ∼50% reduction to a ∼200% increase, with 50 at. % of the cubic second phase. We establish correlations between the properties of the second phase, the transformation characteristics, and the microstructure via the free energy landscape of the two-phase systems. Coherency stresses have a strong influence on the martensitic variants observed and can even cause the non-martensitic second phase to undergo a transformation. Reducing the stiffness of the second phase increases the transformation strain and modifies the martensitic microstructure, increasing the volume fraction of the transformed material. This increase in transformation strain is accompanied by a significant increase in Af and thermal hysteresis, while Ms remains unaltered. Our findings on the tunability of martensitic transformations can be used for informed searches of second phases to achieve desired material properties, such as achieving room temperature, lightweight shape memory alloys.
Graphenes and CNTs: Adatoms, islands, nanocrystals, and intercalants as interacting multipoles
Authors: Lykah V. A. , Syrkin E. S.
Published: March 2020

The functionalization (adsorption) of graphene and carbon nanotubes (CNT) is investigated in the case of charge transfer between a functionalizing molecule (adatom) and a substrate (graphenes or CNT), and the first principles charge transfer calculations are briefly reviewed. It is shown that electrostatic dipoles caused by charge transfer describe the interaction between the adsorbed atoms or islands (clusters) at low concentration, that is, at the initial and intermediate stages of functionalization. It is shown that intercalated atoms in graphite, bi-, and tri-graphene can be described by the electrostatic quadrupoles, their magnitudes are found. The quadrupoles’ axes are perpendicular to the layers. On the surface of the CNT, the adsorbed nanocrystals (clusters) are described as electrostatic quadrupoles, their magnitudes are found. The quadrupoles’ axes are directed along the CNT. At long distances, the interaction energies and repulsion forces are calculated for the clusters. The results explain the experimentally found homogeneous distribution of the adsorbed particles and clusters.
Synthesis and micromechanical properties of graphene oxide-based polymer nanocomposites
Authors: Rusakova H. V. , Fomenko L. S. , Lubenets S. V. , Dolbin A. V. , Vinnikov N. A. , Basnukaeva R. M. , Khlistyuck M. V. , Blyznyuk A. V.
Published: March 2020

The authors have studied the effect of small (≤ 1 wt%) additions of thermally reduced graphene oxide on the microhardness and microindentation kinetics in two types of polymers: polystyrene (i.e. thermoplastic with a glass transition temperature of Tg ≈ 373 K) and polyester resin (i.e. thermosetting plastic, Tg ≈ 300 K). The room temperature creep of nanocomposites under an indenter is described using a three-element rheological Kelvin–Voigt model. The study determines the parameters of this model and how graphene oxide (GO) affects them. In a polystyrene nanocomposite with 0.3 wt % graphene oxide, unrelaxed and relaxed elastic moduli, and the modulus characterizing high-elastic deformation, increase by 11%, 40% and 87%, respectively, as compared to the initial polystyrene; at the same time, microhardness increases by 38% and 45% for the different series of samples. The results obtained indicate that the presence of graphene oxide in the nanocomposite severely restricts the mobility of molecular segments. The addition of 0.3 wt% graphene oxide to polyester resin is accompanied by an increase in the mechanical glass transition temperature of the resin by at least 5 K. This leads to a change in the relaxation state of this polymer: while at room temperature the polyester resin behaves like an elastomer, a polyester resin nanocomposite with 0.3 wt% graphene oxide exhibits glassy properties. At room temperature, the microhardness of polyester resin-glass fabric-graphene oxide nanocomposites with a GO content of 0.5 and 1 wt% increases by 20% and 80% respectively, as compared to that of a polyester resin-glass fabric composite. The authors have obtained the temperature dependences of the microhardness of nanocomposites with a polyester matrix in the range 77–298 K, and have also identified temperature regions where the microdeformation of composites is reversible, which is associated with the formation of crazes with a lower glass transition temperature.
Comparison of temperature dependences of electrical conductivity of composite rGO-SWNT film with rGO and SWNT films
Authors: Kurnosov N. V. , Linnik A. S. , Karachevtsev V. A.
Published: March 2020

Temperature dependences of electrical conductivity of reduced graphene oxide composite with single-walled nanotubes (rGO-SWNTs) and rGO films has been studied in the temperature range of 25–290 K. Both films were obtained by vacuum filtration of aqueous suspensions. Temperature dependences of conductivity of films were found similar to the conductivity observed in disordered semiconducting systems. It was demonstrated that the behavior of the conductivity temperature dependence of pure rGO, SWNTs and composite film is different. The temperature dependences of the resistance R(T) of the films were analyzed within the framework of the variable range hopping (VRH) transport in which electron motion is due to the thermo-activated quantum tunneling between localized states. Two-dimensional Mott VRH (Mott 2D VRH) and Efros-Shklovskii VRH (ES VRH) models were applied for analysis. Mott 2D VRH was observed for rGO-SWNT film in the interval of 25–200 K. At higher temperatures R(T) of rGO-SWNT was fitted with Arrhenius-like equation describing electron activation from localized states to delocalized ones. R(T) of the rGO film followed the Mott 2D VRH model from 165 to 290 K, however, at lower temperatures ES VRH model was exploited. From approximation of R(T) by these models the parameters of the electron transport in rGO-SWNT and rGO films were estimated. It was suggested that nanotubes in rGO-SWNT composite serve as conductive bridges among rGO sheets enhancing the conductivity as compared to rGO. The conductivity of rGO also influences on the composite properties because 2D character of electron motion is kept in sharp contrast to SWNT film which demonstrated three-dimensional Mott VRH electron transport in the same temperature range.
Nontrivial magnetic field related phenomena in the singlelayer graphene on ferroelectric substrate (Review Article)
Authors: Strikha Maksym V. , Morozovska Anna N. , Zemska Zhanna G.
Published: March 2020

The review is focused on our predictions of nontrivial physical phenomena taking place in the nanostructure single-layer graphene on ferroelectric substrate, which are related with magnetic field. In particular we predicted that 180-degree domain walls in a strained ferroelectric film can induce p-n junctions in a graphene channel and lead to the unusual temperature and gate voltage dependences of the perpendicular modes v┴ of the integer quantum Hall effect. The non-integer numbers and their irregular sequence principally differ from the conventional sequence v┴ = 3/2, 5/3, … The unusual v┴-numbers originate from significantly different numbers of the edge modes, v1 and v2, corresponding to different concentration of carriers in the left (n1) and right (n2) ferroelectric domains of p-n junction boundary. The difference between n1 and n2 disappears with the vanishing of the film spontaneous polarization in a paraelectric phase, which can be varied in a wide temperature range by an appropriate choice of misfit strain originated from the film-substrate lattice mismatch. Next we studied the electric conductivity of the system ferromagnetic dielectric-graphene channel-ferroelectric substrate. The magnetic dielectric locally transforms the band spectrum of graphene by inducing an energy gap in it and making it spin-asymmetric with respect to the free electrons. It was demonstrated, that if the Fermi level in the graphene channel belongs to energy intervals, where the graphene band spectrum, modified by EuO, becomes sharply spin-asymmetric, such a device can be an ideal non-volatile spin filter. The practical application of the system under consideration would be restricted by a Curie temperature of a ferromagnet. Controlling of the Fermi level (e.g., by temperature that changes ferroelectric polarization) can convert a spin filter to a spin valve.
Analysis of Ni/Al nanolaminate microstructure offers guidance for customizing ignition
Authors: Mandel Savannah
Published: March 2020

Molecular dynamics simulations reveal that ignition temperature depends on grain size and grain boundary structure in combustible Ni/Al nanolaminates.
Role of grain boundary structure on diffusion and dissolution during Ni/Al nanolaminate combustion
Authors: Witbeck Brandon , Spearot Douglas E.
Published: March 2020

Ni/Al nanolaminates are reactive materials with customizable combustion characteristics. A common approach to synthesize the repeating Ni and Al nanolayers is physical vapor deposition, which often results in columnar grains with ⟨111⟩ texture and grain diameters on the order of a single layer thickness. Changes in grain size have been reported to affect combustion rates, yet the role of individual grain boundaries (GBs) on this process is unclear. Thus, this work investigates the role of the GB structure on atomic diffusion/dissolution and the resulting combustion reaction via molecular dynamics simulations. Nanolaminate combustion is simulated in bicrystal models containing columnar symmetric tilt GBs with ⟨111⟩ misorientation axis perpendicular to the Ni/Al interface. A range of GB misorientation angles is studied, and combustion in a Ni/Al nanolaminate without GBs is simulated for comparison. Combustion in bicrystal models reveals a rise in temperature with an exponential form prior to complete Al melting, while the model without GBs shows a linear temperature increase. Diffusion coefficients are measured for each bicrystal model, and separate Arrhenius fits are used to identify the first three combustion stages. Models containing higher energy GBs generally have higher diffusion coefficients and lower activation energies prior to complete melting of Al, while the GB structure shows little effect on dissolution after the Al layer melts. Thus, the GB structure plays a key role in Ni/Al nanolaminate ignition sensitivity but does not impact runaway combustion.
Role of shell composition and morphology in achieving single-emitter photostability for green-emitting “giant” quantum dots
Authors: McBride James R. , Mishra Nimai , Click Sophia M. , Orfield Noah J. , Wang Feng , Acharya Krishna , Chisholm Matthew F. , Htoon Han , Rosenthal Sandra J. , Hollingsworth Jennifer A.
Published: March 2020

The use of the varied chemical reactivity of precursors to drive the production of a desired nanocrystal architecture has become a common method to grow thick-shell graded alloy quantum dots (QDs) with robust optical properties. Conclusions on their behavior assume the ideal chemical gradation and uniform particle composition. Here, advanced analytical electron microscopy (high-resolution scanning transmission electron microscopy coupled with energy dispersive spectroscopy) is used to confirm the nature and extent of compositional gradation and these data are compared with performance behavior obtained from single-nanocrystal spectroscopy to elucidate structure, chemical-composition, and optical-property correlations. Specifically, the evolution of the chemical structure and single-nanocrystal luminescence was determined for a time-series of graded-alloy “CdZnSSe/ZnS” core/shell QDs prepared in a single-pot reaction. In a separate step, thick (∼6 monolayers) to giant (>14 monolayers) shells of ZnS were added to the alloyed QDs via a successive ionic layer adsorption and reaction (SILAR) process, and the impact of this shell on the optical performance was also assessed. By determining the degree of alloying for each component element on a per-particle basis, we observe that the actual product from the single-pot reaction is less “graded” in Cd and more so in Se than anticipated, with Se extending throughout the structure. The latter suggests much slower Se reaction kinetics than expected or an ability of Se to diffuse away from the initially nucleated core. It was also found that the subsequent growth of thick phase-pure ZnS shells by the SILAR method was required to significantly reduce blinking and photobleaching. However, correlated single-nanocrystal optical characterization and electron microscopy further revealed that these beneficial properties are only achieved if the thick ZnS shell is complete and without large lattice discontinuities. In this way, we identify the necessary structural design features that are required for ideal light emission properties in these green-visible emitting QDs.
Wombat gates effectively exclude browsing mammals from pasture and allow passage of common wombats
Authors: Driessen Michael M. , Gales Rosemary , Hehn Katharina , Dewar Elise , Dobner Guy
Published: March 2020

The effectiveness of wombat gates to allow passage of common wombats (Vombatus ursinus) while excluding other browsing mammals was investigated on a grazing property using camera-traps. During a two-week study period, wombats passed through 17 gates frequently (633 passes) compared with the commonly occurring Tasmanian pademelon (Thylogale billardierii, 33 passes) and red-necked wallaby (Notamacropus rufogriseus, 4 passes). Female wombats with young-at-foot passed through the gates together; however, occasionally they became separated on either side. Wombat gates were effective in providing passage for wombats and restricting passage by browsing macropods and in reducing damage to fences.
Myosin filament-based regulation of the dynamics of contraction in heart muscle
Authors: Brunello Elisabetta , Fusi Luca , Ghisleni Andrea , Park-Holohan So-Jin , Ovejero Jesus G. , Narayanan Theyencheri , Irving Malcolm
Published: March 2020

Significance

Cardiovascular disease continues to be the leading cause of death worldwide, and is frequently associated with heart failure. Efforts to develop better therapeutics for heart failure have been held back by limited understanding of the normal control of contraction on the timescale of the heartbeat. We used synchrotron X-ray diffraction to determine the dynamic structural changes in the myosin motors that drive contraction in the heart muscle, and show that myosin filament-based control mechanisms determine the time course and strength of contraction, allowing those mechanisms to be targeted for developing new therapies for heart disease.
Hanging droplets from liquid surfaces
Authors: Xie Ganhua , Forth Joe , Zhu Shipei , Helms Brett A. , Ashby Paul D. , Shum Ho Cheung , Russell Thomas P.
Published: March 2020

Significance

Heavier objects usually sink in a less dense fluid. Water-walking anthropods and biomimetic water-walking robots harness surface tension in order to overcome this tendency, floating on top of liquids. By hanging a coacervate-encased droplet of a denser aqueous dextran solution from the surface of an aqueous solution of poly(ethylene glycol) (PEG), we harness the binding of dense droplets to interfaces by surface tension to build two-dimensional ensembles of structurally complex droplets. Applications ranging from reaction vessels with selective transport to motors and robotics are enabled by our findings.
Modulation of androgen receptor DNA binding activity through direct interaction with the ETS transcription factor ERG
Authors: Wasmuth Elizabeth V. , Hoover Elizabeth A. , Antar Albert , Klinge Sebastian , Chen Yu , Sawyers Charles L.
Published: March 2020

Significance

Progress in studying the androgen receptor (AR), the primary drug target in prostate cancer, has been hampered by challenges in expressing and purifying active multidomain AR for use in cell-free biochemical reconstitution assays. Here we successfully express full-length and truncated AR variants and demonstrate that the oncogenic ETS protein ERG, responsible for half of all prostate cancers, enhances the ability of AR to bind DNA through direct interaction with AR. In addition to providing a biochemical system to evaluate AR activity on different DNA templates, our findings provide insight into why ERG-positive prostate cancers have an expanded AR cistrome.
Accumulation of high-value bioproducts
in planta
can improve the economics of advanced biofuels
Authors: Yang Minliang , Baral Nawa Raj , Simmons Blake A. , Mortimer Jenny C. , Shih Patrick M. , Scown Corinne D.
Published: March 2020

Significance

Cellulosic biofuels have not yet reached cost parity with conventional petroleum fuels. One strategy to address this challenge is to generate valuable coproducts alongside biofuels. Engineering bioenergy crops to generate value-added bioproducts
in planta
can reduce input requirements relative to microbial chassis and skip costly deconstruction and conversion steps. Although rapid progress has been made in plant metabolic engineering, there has been no systematic analysis devoted to quantifying the impact of such engineered bioenergy crops on biorefinery economics. Here, we provide new insights into how bioproduct accumulation
in planta
affects biofuel selling prices. We present the range of bioproduct selling prices and accumulation rates needed to compensate for additional extraction steps and reach a target $2.50/gal minimum biofuel selling price.
Evolution of hyperossification expands skull diversity in frogs
Authors: Paluh Daniel J. , Stanley Edward L. , Blackburn David C.
Published: March 2020

Frogs (Anura) are one of the most diverse vertebrate orders, comprising more than 7,000 species with a worldwide distribution and extensive ecological diversity. In contrast to other tetrapods, frogs have a highly derived body plan and simplified skull. In many lineages of anurans, increased mineralization has led to hyperossified skulls, but the function of this trait and its relationship with other aspects of head morphology are largely unexplored. Using three-dimensional morphological data from 158 species representing all frog families, we assessed wide-scale patterns of shape variation across all major lineages, reconstructed the evolutionary history of cranial hyperossification across the anuran phylogeny, and tested for relationships between ecology, skull shape, and hyperossification. Although many frogs share a conserved skull shape, several extreme forms have repeatedly evolved that commonly are associated with hyperossification, which has evolved independently more than 25 times. Variation in cranial shape is not explained by phylogenetic relatedness but is correlated with shifts in body size and ecology. The species with highly divergent, hyperossified skulls often have a specialized diet or a unique predator defense mechanism. Thus, the evolution of hyperossification has repeatedly facilitated the expansion of the head into multiple new shapes and functions.
The interplay of prior experience and actual situational context in intercultural first encounters
Authors: Kecskes Istvan
Published: March 2020

The study aims to investigate how prior experience of interlocutors interacts with actual situational context in intercultural interactions when the latter is represented by a well-known frame: getting acquainted with others. It attempts to demonstrate how the cultural frame of the target language is broken up and substituted with an emergent frame that is co-constructed from elements from prior experience with the target language, the first language and the actual situational experience.

Getting acquainted with others is a closed social situation, a cultural frame in which interlocutors usually have to follow a behavior pattern dictated by the requirements of the socio-cultural background in a given speech community. There is a ‘skeleton’ of these ‘getting to know you’ procedures that can be considered universal but is substantiated differently in every language. In each conversation in any language, ‘flesh’ is added to the ‘skeleton’ in a dynamic and co-constructed manner. However, there is a difference between how this happens in L1 and in intercultural interactions. While in L1 the ‘flesh’ on the skeleton is predetermined to a significant extent by requirements of core common ground in the given language, in intercultural encounters this ‘flesh building’ process in the target language (in this case English) is not set but is co-constructed by the interlocutors as emergent common ground relying on their prior experience with their own L1 culture, limited experience with the target culture and the assessment of the actual situational context. In this study the co-construction process, i.e. emergent common ground will be analyzed by examining the use of formulaic language and freely generated language in several discourse segments.
CNS-localized myeloid cells capture living invading T cells during neuroinflammation
Authors: Wasser Beatrice , Luchtman Dirk , Löffel Julian , Robohm Kerstin , Birkner Katharina , Stroh Albrecht , Vogelaar Christina Francisca , Zipp Frauke , Bittner Stefan
Published: March 2020

To study the role of myeloid cells in the central nervous system (CNS) in the pathogenesis of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), we used intravital microscopy, assessing local cellular interactions in vivo in EAE animals and ex vivo in organotypic hippocampal slice cultures. We discovered that myeloid cells actively engulf invading living Th17 lymphocytes, a process mediated by expression of activation-dependent lectin and its T cell–binding partner, N-acetyl-D-glucosamine (GlcNAc). Stable engulfment resulted in the death of the engulfed cells, and, remarkably, enhancement of GlcNAc exposure on T cells in the CNS ameliorated clinical EAE symptoms. These findings demonstrate the ability of myeloid cells to directly react to pathogenic T cell infiltration by engulfing living T cells. Amelioration of EAE via GlcNAc treatment suggests a novel first-defense pathway of myeloid cells as an initial response to CNS invasion and demonstrates that T cell engulfment by myeloid cells can be therapeutically exploited in vivo.
NMDA receptor channel gating control by the pre-M1 helix
Authors: McDaniel Miranda J. , Ogden Kevin K. , Kell Steven A. , Burger Pieter B. , Liotta Dennis C. , Traynelis Stephen F.
Published: March 2020

The NMDA receptor (NMDAR) is an ionotropic glutamate receptor formed from the tetrameric assembly of GluN1 and GluN2 subunits. Within the flexible linker between the agonist binding domain (ABD) and the M1 helix of the pore-forming transmembrane helical bundle lies a two-turn, extracellular pre-M1 helix positioned parallel to the plasma membrane and in van der Waals contact with the M3 helix thought to constitute the channel gate. The pre-M1 helix is tethered to the bilobed ABD, where agonist-induced conformational changes initiate activation. Additionally, it is a locus for de novo mutations associated with neurological disorders, is near other disease-associated de novo sites within the transmembrane domain, and is a structural determinant of subunit-selective modulators. To investigate the role of the pre-M1 helix in channel gating, we performed scanning mutagenesis across the GluN2A pre-M1 helix and recorded whole-cell macroscopic and single channel currents from HEK293 cell-attached patches. We identified two residues at which mutations perturb channel open probability, the mean open time, and the glutamate deactivation time course. We identified a subunit-specific network of aromatic amino acids located in and around the GluN2A pre-M1 helix to be important for gating. Based on these results, we are able to hypothesize about the role of the pre-M1 helix in other NMDAR subunits based on sequence and structure homology. Our results emphasize the role of the pre-M1 helix in channel gating, implicate the surrounding amino acid environment in this mechanism, and suggest unique subunit-specific contributions of pre-M1 helices to GluN1 and GluN2 gating.
Molecular mechanism of BK channel activation by the smooth muscle relaxant NS11021
Authors: Rockman Michael E. , Vouga Alexandre G. , Rothberg Brad S.
Published: March 2020

Large-conductance Ca2+-activated K+ channels (BK channels) are activated by cytosolic calcium and depolarized membrane potential under physiological conditions. Thus, these channels control electrical excitability in neurons and smooth muscle by gating K+ efflux and hyperpolarizing the membrane in response to Ca2+ signaling. Altered BK channel function has been linked to epilepsy, dyskinesia, and other neurological deficits in humans, making these channels a key target for drug therapies. To gain insight into mechanisms underlying pharmacological modulation of BK channel gating, here we studied mechanisms underlying activation of BK channels by the biarylthiourea derivative, NS11021, which acts as a smooth muscle relaxant. We observe that increasing NS11021 shifts the half-maximal activation voltage for BK channels toward more hyperpolarized voltages, in both the presence and nominal absence of Ca2+, suggesting that NS11021 facilitates BK channel activation primarily by a mechanism that is distinct from Ca2+ activation. 30 µM NS11021 slows the time course of BK channel deactivation at −200 mV by ∼10-fold compared with 0 µM NS11021, while having little effect on the time course of activation. This action is most pronounced at negative voltages, at which the BK channel voltage sensors are at rest. Single-channel kinetic analysis further shows that 30 µM NS11021 increases open probability by 62-fold and increases mean open time from 0.15 to 0.52 ms in the nominal absence of Ca2+ at voltages less than −60 mV, conditions in which BK voltage sensors are largely in the resting state. We could therefore account for the major activating effects of NS11021 by a scheme in which the drug primarily shifts the pore-gate equilibrium toward the open state.
Guidelines for designing the antithetic feedback motif
Authors: Baetica Ania-Ariadna , Leong Yoke Peng , Murray Richard M
Published: March 2020

Integral feedback control is commonly used in mechanical and electrical systems to achieve zero steady-state error following an external disturbance. Equivalently, in biological systems, a property known as robust perfect adaptation guarantees robustness to environmental perturbations and return to the pre-disturbance state. Previously, Briat et al proposed a biomolecular design for integral feedback control (robust perfect adaptation) called the antithetic feedback motif. The antithetic feedback controller uses the sequestration binding reaction of two biochemical species to record the integral of the error between the current and the desired output of the network it controls. The antithetic feedback motif has been successfully built using synthetic components in vivo in Escherichia coli and Saccharomyces cerevisiae cells. However, these previous synthetic implementations of antithetic feedback have not produced perfect integral feedback control due to the degradation and dilution of the two controller species. Furthermore, previous theoretical results have cautioned that integral control can only be achieved under stability conditions that not all antithetic feedback motifs necessarily fulfill. In this paper, we study how to design antithetic feedback motifs that simultaneously achieve good stability and small steady-state error properties, even as the controller species are degraded and diluted. We provide simple tuning guidelines to achieve flexible and practical synthetic biological implementations of antithetic feedback control. We use several tools and metrics from control theory to design antithetic feedback networks, paving the path for the systematic design of synthetic biological controllers.
Analysis of Mathematical Critical Thinking Skill of Junior High School Students on the Two-Variable Linear Equation System
Authors: Utami P , Bharata H
Published: March 2020

This study aimed to analyze the students’ mathematical critical thinking skill on the two-variable linear equations system. This research is a descriptive study with a qualitative approach. The subject of this study was 32 students of grade 8 in Junior High School Satu Atap 3, Jati Agung, Lampung. The data collection techniques used Critical Thinking Instrument with two problem descriptions. Furthermore, the data collected was analyzed based on indicators of critical thinking skill set by the researchers which included interpretation, analysis, evaluation, and inference. Based on the data analysis, the average of critical thinking skill of students is 52.15%, in the low category. The percentage of interpretation aspects is 53.13%, in the low category, the analysis aspect is 52.73% in the low category, the evaluation aspect is 54.30%, in the low category, and the inference aspect is 48.44%, in the low category. The results of this study indicated that the students’ critical thinking skills are still low so it is expected that by knowing these conditions the teachers and researchers are able to choose, design, and develop the learning that facilitates the students to practice critical thinking.
The Effectiveness of STEM Learning: Scientific Attitudes and Students’ Conceptual Understanding
Authors: Thahir A , Anwar C , Saregar A , Choiriah L , Susanti F , Pricilia A
Published: March 2020

This study aims to see the effectiveness of the learning approaches toward scientific attitudes and conceptual understanding. The research method used was quasi-experimental research with a pretest-posttest control design. The scientific attitude data was obtained using a questionnaire while the conceptual understanding data was obtained through a test instrument in the form of a description item. The results of the study are (1) there are differences in scientific attitudes and students’ conceptual understanding taught using STEM learning approach and conventional learning, (2) there is a difference in conceptual understanding between students who were taught using the STEM learning approach and conventional learning, and (3) there are significant differences in scientific attitudes between students who were taught using the STEM learning approach and students who were taught using conventional learning.
The Development of Biology Module Based on Local Wisdom of West Lampung: Study of Ecosystem Material
Authors: Haka N B , Anggoro B S , Hamid A , Novitasari A , Handoko A , Puspita L
Published: March 2020

Education has a mission to develop the potential of students, develop their personality, and be able to foster a sense of responsibility. For this reason, teaching materials are needed. Module teaching materials based on local wisdom on ecosystem materials are not yet available as Teaching materials used by schools. For this reason, it was necessary to develop module teaching materials based on local wisdom in supporting the achievement of competencies and learning objectives. This study aimed to determine the development, feasibility and response of students and educators towards the Biology module based on local wisdom in West Lampung. This study used Research & Development (R&D) method with Borg & Gall procedure. Data collection techniques were using expert questionnaires (teaching modules, materials, languages), response questionnaires (students and educators), and documentation. Riduwan modified Likert scale research data analysis techniques were used. The results showed the module was suitable for using in the learning process based on the module quality assessment by experts (teaching modules, material, and language) with overall criteria very feasible. Biology educator’s response was very positive towards the teaching module products. It could be concluded that the module is suitable for use in the biology learning process.