bluuebunny/crossref_metadata_2025 huggingface dataset:
Face recognition algorithm based on feature descriptor and weighted linear sparse representation
Authors: Liao Mengmeng , Gu Xiaodong
Published: August 2019

Generally, the commonly used sparse‐based methods, such as sparse representation classifier, have achieved a good recognition result in face recognition. However, there exist several problems in those methods. First, those methods think that the importance of each atom is the same in representing other query samples. This is not reasonable because different atoms contain different amounts of information, their importance should be different when they together represent the query samples. Second, those methods cannot meet the real‐time requirement when dealing with large data set. In this study, on the one hand, the authors propose a fast extended sparse‐weighted representation classifier (FESWRC) by considering the different importance of atoms and using primal augmented Lagrangian method as well as principal component analysis. On the other hand, the authors propose a distinctive feature descriptor, named logarithmic‐weighted sum (LWS) feature descriptor. The authors combine FESWRC and LWS and used for face recognition, this method is called face recognition algorithm based on feature descriptor and weighted linear sparse representation (FDWLSR). Experimental results show that FDWLSR can realise real‐time recognition and the recognition rate can achieve 100.0, 100.0, 91.6, 93.4 and 87.4%, respectively, on the Yale, Olivetti Research Laboratory (ORL), faculdade de engenharia industrial (FEI), face recognition technology program (FERET) and labelled face in the wild datasets.
New image‐guided method for localisation of an active capsule endoscope in the stomach
Authors: Aghanouri Mehrnaz , Ghaffari Ali , Serej Nasim Dadashi , Rabbani Hossein , Adibi Peyman
Published: August 2019

Localisation of an active capsule endoscope inside the stomach has different challenges. One of them is the estimation of the capsule's roll angle. Another challenge is adjusting the distance between the capsule and the stomach to achieve high‐quality imaging in the region of interest. In this study, an optimised image‐guided localisation (O‐Localisation) method is proposed to estimate the roll angle and the scale factor between the consecutive frames. The distance between the capsule and walls of the stomach can be adjusted using the suggested fuzzy adjuster, which is developed based on the estimated scale factors and calibration parameters. This new method is only based on visual information extracted from wireless capsule endoscope video frames. The results show that this method can accurately estimate the rotation angles and scale factors with errors <0.2% for the angles up to 90° and 0.3% for the scales up to 5, respectively. The method is robust to the brightness changes up to 80% with a maximum error of 0.3%. The computational time is about 1 s and can be considered near real‐time for this application. Accordingly, the O‐Localisation method as a real‐time, robust and precise method for capsule localisation can provide a more efficient controllable and steerable capsule endoscopes.
Enhanced MPPT method based on ANN‐assisted sequential Monte–Carlo and quickest change detection
Authors: Chen Leian , Wang Xiaodong
Published: August 2019

The performance of a photovoltaic system is subject to varying environmental conditions, and it becomes more challenging to track the maximum power point (MPP) and maintain the optimal performance when partial shading occurs. In this study, an enhanced MPP tracking (MPPT) method is proposed utilising the state estimation by the sequential Monte–Carlo (SMC) filtering, which is assisted by the prediction of MPP via an artificial neural network (ANN). A state‐space model for the sequential estimation of MPP is proposed in the framework of incremental conductance MPPT approach, and the ANN model based on the observed voltage and current or irradiance data predicts the global MPP to refine the estimation by SMC. Moreover, a quick irradiance change detection method is applied, such that the SMC‐based MPPT method resorts to the assistance from ANN only when partial shading is detected. Simulation results show that the proposed enhanced MPPT method achieves high efficiency and is robust to rapid irradiance change.
Multimodulares kognitives Training für Mitarbeiter in der Pflege 50+: Erste Ergebnisse einer Pilotstudie zur Durchführbarkeit und Wirksamkeit
Authors: Buschert Verena Caroline , Grishina Anna , Feichtner Anita
Published: August 2019

Ziel der Studie war die Prüfung der Durchführbarkeit eines kognitiven Trainings für Mitarbeiter der Pflege 50+.

Methodik Dazu wurde ein kognitives Trainingsprogramm (13 Stunden, 5 Termine) mit 15 Pflegekräften des Klinikums der Universität München (KUM) durchgeführt und die Akzeptanz sowie Effekte auf kognitive und psychische Leistungspotenziale ermittelt.

Ergebnisse Die Maßnahme wurde von den Teilnehmern sehr gut angenommen und positiv bewertet. Zudem zeigten sich signifikante Verbesserungen in kognitiven Leistungsbereichen und in der Selbstwirksamkeit.

Schlussfolgerung Das Trainingsprogramm lässt sich als regelmäßiges Angebot implementieren, erste Hinweise auf positive Trainingseffekte müssen im Rahmen randomisierter kontrollierter Studien bestätigt werden.
Synthesis of Asymmetrical 2,6-Diarylpyridines from Linear α,β,γ,δ-Unsaturated Ketones by Addition of Ammonium Formate Followed by Annulation
Authors: Gao Yejun , Chen Rener , Ma Yongmin
Published: August 2019

A simple and efficient method has been established for the synthesis of asymmetrical 2,6-diarylpyridines by cyclization of α,β,γ,δ-unsaturated ketones with ammonium formate under air atmosphere. The reaction is metal-free and operationally convenient from readily available starting materials. Thirty-three examples have been presented, most of which show good yields.
Morphological Variations of an Atypical Cleft Hand: A Cadaveric Case Report
Authors: Sirasanagandla Srinivasa Rao , Al Mushaiqri Mohamed , Al Khabori Hussein Saleem Jawad , Al Rashdi Roaa Abdullah Mohsin
Published: August 2019

Cleft hand is a group of hand deformities in which the central digits of the hand are congenitally absent. The soft tissue variations of cleft hand are rarely described. Hence, we report the anatomic variants of a unilateral atypical cleft hand with the absence of all of the phalanges of the middle finger. The 2nd and 3rd lumbricals showed a variation in their distal attachment. Both the superficial and deep flexor digital tendons of the missing middle finger were fused and inserted into the palmar surface of the head of the 3rd metacarpal bone. The extensor digitorum tendon of the missing finger was inserted on the dorsal surface of the head of the 3rd metacarpal bone. The palmar digital nerves of the median nerve of the middle finger formed 2 visible fibrotic masses; radial and ulnar, over the base of the 2nd web space. Of these, the radial mass was formed by the fusion of both palmar digital nerves and the common palmar digital artery. The knowledge of soft tissue abnormalities reported here is clinically important to plastic surgeons while restoring the good grasp and pinch of the cleft hand. The occurrence of fibrotic masses reported in the present case is unique, and these masses may cause diagnostic errors during an angiographic procedure.
Evaluation of the Impacts of Chemotherapeutics on Odontogenesis Process: Findings from a Systematic Review
Authors: Smith Camila Valente , Silva Grazyelle Sebrenski da , Silva Felipe Rodolfo Pereira da , Barcellos José Fernando Marques , Furtado Silvânia da Conceição
Published: August 2019

This study aimed to examine and recognize the impacts of antinoplastic chemotherapeutics on the development of dental germ, employing a systematic review. A retrieving in the literature was carried out, using several medical and scientifical databases (ClinicalKey, Cochrane Library, Google Scholar, MedLine, PubMed, and ScienceDirect), by two investigators separately. In the end of this systematic search, eight articles met the required criteria for inclusion and, therefore, composed the results. Among these, four articles are about observational studies in humans, and the other four about experimental animal studies. In both cases and species, anomalies such as microdontia, hypodontia/agenesia, and root shortening were observed. The severity and frequency varied according to the nature of the chemotherapeutics applied as well as the administered dosage and the patient's age at the time of first exposure. Through the results, it was possible to show the direct impacts of chemotherapy on the odontogenesis process as well as factors such as the type of chemotherapy, the age of the individual at the time of first exposure and the dosage used. All of those should be taken into account when choosing a therapeutic protocol for an oncology patient. Besides, we observed the need for more studies in this area and that these should be standardized in order to allow an objective and direct analysis of comparable parameters, even when different approaches are used.
Anatomical Variation of the Azygos System of Veins - Case Report
Authors: Brito Josikwylkson Costa , Falcão Vlademir Lourenço , Gomes Ana Luisa Castelo Branco , Queiroga Deyvsom Felipe de Sousa , Barroso Luciana Karla Viana
Published: August 2019

Introduction The azygos system of veins (ASV) is a very variable structure characterized as a communication between the inferior and superior vena cava, having the azygos vein (AV), the hemiazygos vein (HV), and the accessory hemiazygos vein (HAV) as its main components, which are responsible for the mediastinal viscera and for the thoracoabdominal wall drainage. The aim of the present study is to report an anatomical variation found in a male cadaver at the Laboratory of Anatomy of the University Center of UNIFACISA, Campina Grande, PB, Brazil.

Case Report In the posterior mediastinum, the union of the HV, of the HAV, and of the 8th left posterior intercostal vein formed a common trunk at the level of the left 8th intercostal space, crossing the mediastinum posterior to the aorta artery, ending up in the AV, in the right hemithorax.

Conclusion The study of the anatomical variations of the ASV is important and will provide knowledge for physicians not to confuse them with pathological processes in imaging exams. Moreover, it can provide safety in surgical approaches of the thorax.
Primary Results of Medial Epicondylar Osteotomy in Patients with Severe Bilateral Varus Knee Candidate for Total Knee Replacement
Authors: Mirzatolooei Fardin , Tabrizi Ali , Taleb Hassan , Hashemian Mohammad Khalegi , Safari Mir Bahram
Published: August 2019

Total knee arthroplasty is a challenging task in patients with severe varus deformity. In most of these patients, an extensive medial release is needed that may lead to instability. Medial epicondylar osteotomy may be a better substitute for complete medial collateral release. Fourteen patients with bilateral knee osteoarthritis and severe varus deformity were enrolled in this study. In one side, the patients underwent medial epicondylar osteotomy for mediolateral imbalance if the only option was superficial medial collateral ligament (MCL) release. In contralateral side, the extensive medial release was performed and MCL was released either by pie-crusting technique or by subperiosteally release. The results of the two sides were compared. Patients were followed up for 12 months after the operation. Physical examination, clinical questionnaires, and radiography findings were recorded. Union of the osteotomies fragment and complications was evaluated. The mean varus angle before surgery was 21.6 ± 4.7 degrees, which was corrected to 8.6 ± 2.9 degrees after operation with an extensive medial release. The mean varus angle of contralateral side was 22.6 ± 1.7 degrees, which was corrected to 7.5 ± 2.3 degrees following medial femoral epicondyle osteotomy. There was no significant difference in varus correction (p = 0.1). Medial joint line opening in valgus stress test was 2.7 ± 0.4 mm in the osteotomized side and 3.5 ± 0.9 mm in contralateral side. Mean range of motion for the osteotomized side was 97.8 ± 4.3 degrees and 100.7 ± 2.7 degrees for contralateral side (p = 0.6). Nonunion occurred in a case in the osteotomized side and no medial instability was observed in medial release or osteotomies sides. No statistical difference was recorded based on clinical questionnaires (Oxford and WOMAC [Western Ontario and McMaster Universities Osteoarthritis Index] scores). Medial epicondylar osteotomy is a safe technique with the well-controlled medial extensive release in the patients with severe varus deformity during total knee arthroplasty.
Dorsal Bridge Plating versus External Fixation for Distal Radius Fractures
Authors: Wang William L. , Ilyas Asif M.
Published: August 2019

Background External fixation and dorsal bridge plating are wrist spanning fixation options for distal radius fractures; however, their comparative effectiveness is not well understood. A meta-analysis was conducted to compare the clinical outcomes between these two techniques.

Materials and Methods A PubMed database query of all distal radius fracture cases managed with spanning external fixation or dorsal bridge plating was performed. A total of 28 articles met inclusion criteria, yielding 895 patients for data extraction and comparative analysis.

Results Dorsal bridge plating demonstrated lower rates of infection (2 vs. 10%, p = 0.05) and complex regional pain syndrome (1 vs. 4%, p = 0.04) but higher rates of hardware failure (4 vs. 1%, p = 0.026). Bridge plating also demonstrated higher rates of excellent/good ratings under the Gartland and Werley outcome score (91 vs. 83%, p = 0.016). There was no significant difference in DASH (Disability of the Arm, Shoulder, and Wrist) scores, radiographic parameters, or unplanned reoperations between the two spanning fixation options.

Conclusion Bridge plating and external fixation both appear to be comparable for spanning fixation constructs for distal radius fractures, but with bridge plating having a potentially lower complication profile.
A flux-balanced fluid model for collisional plasma edge turbulence: Numerical simulations with different aspect ratios
Authors: Qi Di , Majda Andrew J. , Cerfon Antoine J.
Published: August 2019

We investigate the drift wave–zonal flow dynamics in a shearless slab geometry with the new flux-balanced Hasegawa-Wakatani model. As in previous Hasegawa-Wakatani models, we observe a sharp transition from a turbulence dominated regime to a zonal jet dominated regime as we decrease the plasma resistivity. However, unlike previous models, zonal structures are always present in the flux-balanced model, even for high resistivity, and strongly reduce the level of particles and vorticity flux. The more robust zonal jets also have a higher variability than in previous models, which is further enhanced when the computational domain is chosen to be elongated in the radial direction. In these cases, we observe complex multiscale dynamics, with multiple jets interacting with one another, and intermittent bursts. We present a detailed statistical analysis which highlights how the changes in the aspect ratio of the computational domain affect the third-order statistical moments, and thus modify the turbulent dynamics. By changing the aspect ratio and extending either the radial or the binormal direction, the present model study offers a better approximation to mimic turbulence in flux tube simulations for either very low magnetic shear or very high magnetic shear systems.
Quadrupolar mechanism for vibrational sum frequency generation at air/liquid interfaces: Theory and experiment
Authors: Matsuzaki Korenobu , Nihonyanagi Satoshi , Yamaguchi Shoichi , Nagata Takashi , Tahara Tahei
Published: August 2019

Vibrational sum frequency generation (VSFG) spectroscopy has been widely utilized to investigate various interfaces through molecular vibration. VSFG is usually attributed to the breakdown of the inversion symmetry at the interface within the electric dipole approximation. Although the electric dipole approximation is a very good approximation in the isotropic bulk, its validity is questionable at the interface because a large electric field gradient exists in the thin interface region. Thus, the quadrupole contribution may become significant at the interface. Here, we discuss the quadrupole contribution in VSFG from theoretical and experimental viewpoints. We describe a theory as to how the quadrupole contribution appears in experimental VSFG spectra by deriving the vibrational selection rule and discussing the interface selectivity. With this theoretical framework, we examine the mechanism of VSFG at the air/benzene and air/decane interfaces. The accurate determination of the vibrational frequencies realized by heterodyne-detected VSFG spectroscopy reveals that VSFG at the air/benzene interface arises from the quadrupolar mechanism. This means that the observation of VSFG does not imply a molecular alignment so that interfacial benzene molecules may be randomly oriented. Meanwhile, at the air/decane interface, it is concluded that the VSFG signal arises from the ordinary dipolar mechanism. This implies that decane molecules are aligned in a preferential direction at the interface despite their low polarity. This study demonstrates the importance of examining the mechanism of VSFG before discussing the interfacial structure based on VSFG spectra. A strategy to distinguish different mechanisms is also proposed. The present study further shows that the quadrupolar mechanism, if properly taken into consideration, enables us to obtain information about interfacial molecules beyond the restriction of the inversion symmetry breaking required by the dipolar mechanism, through the large electric field gradient localized at the interface.
Effect of surface termination on the lattice thermal conductivity of monolayer Ti3C2Tz MXenes
Authors: Gholivand Hamed , Fuladi Shadi , Hemmat Zahra , Salehi-Khojin Amin , Khalili-Araghi Fatemeh
Published: August 2019

Recently, two-dimensional transition metal carbides and nitrides (MXenes) have gained significant attention in electronics and electrochemical energy conversion and storage devices where the heat production significantly affects the safety and performance of these devices. In this paper, we have studied the thermal transport in monolayer Ti3C2Tz, the first and most studied MXene, using density functional theory and the phonon Boltzmann transport equation and quantified the effect of surface termination (bare, fluorine, and oxygen) on its lattice thermal conductivity. We found that the thermal conductivity of fluorine-terminated Ti3C2Tz (108 W/m K) is approximately one order of magnitude higher than its oxygen-terminated counterpart (11 W/m K). Our calculations reveal that the increased thermal conductivity for the fluorine-terminated structure is due to its enhanced specific heat and group velocity and diminished scattering rate of phonons.
Transition frequency of transport ac losses in high temperature superconducting coated conductors
Authors: Zhou Pengbo , Ma Guangtong , Quéval Loïc
Published: August 2019

Experimental data reveal that the classical description of transport ac losses in high-temperature superconducting (HTS)-coated conductors (CCs), based on investigations at low frequencies, is incomplete in some aspects when transport currents in the kilohertz range are considered. More specifically, above a certain “transition frequency,” the ac losses per cycle no longer increase with the frequency as the theory predicts. Using a finite element model to allow for loss separation, we find that this phenomenon is caused by a combination of several factors that appear only above the transition frequency: the hysteresis and ferromagnetic losses per cycle are no longer independent of the frequency, while the eddy current losses per cycle no longer increase proportionally to the frequency. Based on a circuit model, we propose that the physical reason for this is that when the frequency increases, part of the supercurrent starts migrating into the metallic path. We argue that the current in the metallic path is not an eddy current but a transport current inductively coupled to the superconducting current. Finally, we discuss the relationship between the magnetic material magnetization, the critical current, and the transport current frequency. This study provides explicit insights into the frequency-dependent transport ac losses of HTS CCs in a broad frequency band, which is valuable for the design and optimization of HTS CC-based power devices.
Mean force kinetic theory: A convergent kinetic theory for weakly and strongly coupled plasmas
Authors: Baalrud Scott D. , Daligault Jérôme
Published: August 2019

A new closure of the BBGKY hierarchy is developed, which results in a convergent kinetic equation that provides a rigorous extension of plasma kinetic theory into the regime of strong Coulomb coupling. The approach is based on a single expansion parameter which enforces that the exact equilibrium limit is maintained at all orders. Because the expansion parameter does not explicitly depend on the range or the strength of the interaction potential, the resulting kinetic theory does not suffer from the typical divergences at short and long length scales encountered when applying the standard kinetic equations to Coulomb interactions. The approach demonstrates that particles effectively interact via the potential of mean force and that the range of this force determines the size of the collision volume. When applied to a plasma, the collision operator is shown to be related to the effective potential theory [S. D. Baalrud and J. Daligault, Phys. Rev. Lett. 110, 235001 (2013)]. In addition to the collision operator, this systematic derivation reveals a second term that is related to the excess (nonideal) components of the pressure and internal energy in the hydrodynamic limit. The relationship between this and previous kinetic theories is discussed.
Experimental measurements of the RF sheath thickness with a cylindrical Langmuir probe
Authors: Faudot E. , Ledig J. , Moritz J. , Heuraux S. , Lemoine N. , Devaux S.
Published: August 2019

The small layer oscillating in front of a radio frequency (rf) biased electrode in an asymmetric rf plasma discharge without a magnetic field is diagnosed using an rf compensated cylindrical probe. Thanks to this probe (0.15 mm in diameter), the floating potential is measured in this area. Radio frequency plasmas and sheath properties are then derived from the I-V characteristics measured by the probe at different rf power levels in both capacitive and direct couplings. In direct coupling, the plasma biasing is, as expected, nearly equal to the applied rf potential except at high power levels for which the current collected by the electrode saturates and the sheath potential gap is reversed. In capacitive coupling, the self-biasing of the electrode is strongly negative due to the matching box used. From the difference between the plasma potential and the floating potential, we found a sheath thickness of about 3 λDe. Within the rf power scan performed, the sheath thicknesses deduced from the potential and density profiles are 3 times higher than those from the Child–Langmuir law both in direct and capacitive coupling in a low collisional helium plasma.
Anharmonic vibrational computations with a quartic force field for curvilinear coordinates
Authors: Harabuchi Yu , Tani Ryosuke , De Silva Nuwan , Njegic Bosiljka , Gordon Mark S. , Taketsugu Tetsuya
Published: August 2019

The direct vibrational self-consistent field (VSCF) method, which combines anharmonic vibrational theory with electronic structure calculations, is a sophisticated theoretical approach to calculate the vibrational spectra of molecules from first principles. Combining the VSCF approach with the quartic force field (QFF) is a good alternative to direct VSCF, with a lower computational cost. QFF is a 4th-order Taylor expansion of the potential energy surface near an equilibrium geometry. In this study, a new strategy is proposed to derive the QFF in terms of normal coordinates; the QFF coefficients are determined through numerical differentiations of the energy by representing the normal coordinates in internal rather than Cartesian coordinates. The VSCF/QFF-internal method was implemented in the General Atomic and Molecular Electronic Structure System electronic structure program and applied to the evaluations of the fundamental vibrational frequencies of HNO2, HNO3, H2O dimer, and H2O trimer, using Møller-Plesset second order perturbation theory and the aug-cc-pVDZ and aug-cc-pVTZ basis sets. The results are much improved, especially for the intermolecular vibrational modes, compared with the Cartesian coordinate representation of the normal coordinates in the VSCF/QFF approach.
Can the distinguishable cluster approximation be improved systematically by including connected triples?
Authors: Rishi Varun , Valeev Edward F.
Published: August 2019

The Distinguishable Cluster (DC) approximation to the coupled cluster (CC) doubles, proposed by Kats and Manby [J. Chem. Phys. 139, 021102 (2013)], can semiquantitatively describe multiple bond dissociation (which is traditionally considered a paradigm of strongly correlated electronic structure methods based on the multideterminant approach) without leaving the single-reference coupled cluster framework. DC is just one of many internally corrected (CC) methods that improve on the parent CC method by approximation. To build on the success of the DC methods, it is important to probe whether they can be systematically improved. To answer this question, we considered a set of methods in the distinguishable cluster family, culminating in the DC singles, doubles, and triples (DCSDT), a DC modification of the parent CC singles, doubles, and triples that maintains exactness for 3-electron systems. Inclusion of the complete treatment of triples leads to systematic improvement over the DCSD for equilibrium correlation energy estimates. However, this improvement is not matched by enhanced accuracy for multiple bond breaking processes.
On the forward/backward symmetry of transition path time distributions in nonequilibrium systems
Authors: Berezhkovskii Alexander M. , Makarov Dmitrii E.
Published: August 2019

Recent single-molecule studies have been able to observe molecular transition paths, i.e., short and rare excursions where the molecule is caught in transit from one stable molecular conformation to another, motivating a flurry of theoretical work. Under equilibrium conditions, the temporal duration of a transition path, or the transition path time, exhibits a fundamental property that is a consequence of the time reversal symmetry: the distribution of the transition path time is independent of the transition direction (forward or backward). Many conformational changes occurring in living systems, however, take place away from equilibrium. Molecular motors, for example, make more steps in the forward than in the backward direction, resulting in overall unidirectional motion. Is the symmetry between the transition path times for individual steps in the forward and backward directions preserved in this case? Here, we show that this symmetry is still preserved if the transition occurs between (precisely) known microscopic states. However, since most experiments can only monitor some low-dimensional property of the system (e.g., the position of the molecular motor along its track), this symmetry, when applied to experimental observations, is generally broken, except in equilibrium. In a different language, the forward/backward symmetry violation occurs only if two conditions are met simultaneously: (1) the dynamics of the low-dimensional experimental observables is non-Markovian and (2) the system is not in equilibrium.
Triaxial strain engineering of magnetic phase in phosphorene
Authors: Bui H. D. , Davoudiniya M. , Yarmohammadi M.
Published: August 2019

In the present paper, we theoretically address and predict the magnetic properties of monolayer phosphorene under different triaxial strains. For this purpose, we use the tight-binding Hamiltonian model and the Harrison rule aiming at studying the strain-induced phosphorene structure. Our findings indicate how the electronic phase transition is related to the magnetic phase transition in phosphorene. The details of this connection are extracted from the bandgap-dependent Neel temperature of the antiferromagnetic ground state phase as well as the state degeneracy-dependent Pauli spin paramagnetic susceptibility. We found that phosphorene keeps its semiconductor nature for the uniform and nonuniform triaxial strains (both compressive and tensile strains), resulting in no magnetic phase transition, whereas the in-plane uniform triaxial strains lead to a semiconductor-to-semimetal and consequently an antiferromagnetic-to-ferromagnetic phase transition on average. Furthermore, we show that the armchair edge possesses the most contribution to the electronic and magnetic phases of monolayer phosphorene. These results provide useful information for future experimental research studies in both optoelectronic and spintronic applications.
Evaluating two-electron-repulsion integrals over arbitrary orbitals using zero variance Monte Carlo: Application to full configuration interaction calculations with Slater-type orbitals
Authors: Caffarel Michel
Published: August 2019

A Monte Carlo method for evaluating multicenter two-electron-repulsion integrals over any types of orbitals (Slater, Sturmian, finite-range, numerical, etc.) is presented. The approach is based on a simple and universal (orbital-independent) gaussian sampling of the two-electron configuration space and on the use of efficient zero-variance Monte Carlo estimators. Quite remarkably, it is shown that the high level of accuracy required on two-electron integrals to make Hartree-Fock (HF) and configuration interaction (CI) calculations feasible can be achieved. A first zero-variance estimator is built by introducing a gaussian approximation of the orbitals and by evaluating the two-electron integrals using a correlated sampling scheme for the difference between exact and approximate orbitals. A second one is based on the introduction of a general coordinate transformation. The price to pay for this simple and general Monte Carlo scheme is the high computational cost required. However, we argue that the great simplicity of the algorithm, its embarrassingly parallel nature, its ideal adaptation to modern computational platforms and, most importantly, the possibility of using more compact and physically meaningful basis sets nevertheless make the method attractive. HF and near full CI (FCI) calculations using Slater-type orbitals (STOs) are reported for Be, CH4, and [H2N(CH)NH2]+ (a simple model of cyanine). To the best of our knowledge, our largest FCI calculation involving 18 active electrons distributed among 90 orbitals for the cyanine molecule is the most extensive molecular calculation performed so far using pure STOs (no gaussian approximation, even for the challenging four-center two-electron integrals).
High-resolution photoelectron spectroscopy of the pyridinide isomers
Authors: DeVine Jessalyn A. , Babin Mark C. , Blackford Katherine , Neumark Daniel M.
Published: August 2019

Isomer-specific, high-resolution photoelectron spectra of cryogenically cooled pyridinide anions obtained using slow photoelectron velocity-map imaging are presented. New vibrational structure in the detachment spectrum of para-pyridinide is resolved, and the spectra of meta- and ortho-pyridinide are reported for the first time. These spectra yield electron affinities of 1.4797(5), 1.4473(5), and 0.8669(7) eV for the para-, meta-, and ortho-pyridyl radicals, respectively, as well as a number of vibrational frequencies for each neutral isomer. While most of the resolved structure in all three spectra is readily assigned by comparison to B3LYP/6-311+G* Franck-Condon simulations, the para-pyridinide spectrum shows newly resolved fine structure attributed to anharmonic coupling within the vibrational manifold of the corresponding neutral radical. Isomeric trends in the photoelectron angular distributions are rationalized by approximating the detached anion orbitals as superpositions of s-, p-, and d-like hydrogenic orbitals, based on an application of Sanov’s generalized mixing model [D. Khuseynov et al., J. Chem. Phys. 141, 124312 (2014)]. The presented experimental and theoretical results are used to address the relative energies of the anion and neutral isomers, as well as the site-specific bond dissociation energies of pyridine.
Fourier-transform microwave spectroscopy on weakly bound complexes of CH2OO with Ar, CO, and N2
Authors: Nakajima Masakazu , Endo Yasuki
Published: August 2019

Pure rotational transitions of weakly bound complexes of the simplest Criegee intermediate CH2OO with Ar, CO, and N2 are observed by Fourier-transform microwave (FTMW) and FTMW-MW double-resonance spectroscopy. Many of the observed lines show doublet peaks associated with the tunneling splitting between the two equivalent configurations of the complexes. The intermolecular distances of the complexes are derived from the precise rotational constants determined in this study. The separations between two components of the doublet peaks observed for c-type transitions of CH2OO–Ar are satisfactorily demonstrated by a one-dimensional hindered rotor model for the internal rotation of the CH2OO monomer.
The crystal structure of human microsomal triglyceride transfer protein
Authors: Biterova Ekaterina I. , Isupov Michail N. , Keegan Ronan M. , Lebedev Andrey A. , Sohail Anil A. , Liaqat Inam , Alanen Heli I. , Ruddock Lloyd W.
Published: August 2019

Microsomal triglyceride transfer protein (MTP) plays an essential role in lipid metabolism, especially in the biogenesis of very low-density lipoproteins and chylomicrons via the transfer of neutral lipids and the assembly of apoB-containing lipoproteins. Our understanding of the molecular mechanisms of MTP has been hindered by a lack of structural information of this heterodimeric complex comprising an MTPα subunit and a protein disulfide isomerase (PDI) β-subunit. The structure of MTP presented here gives important insights into the potential mechanisms of action of this essential lipid transfer molecule, structure-based rationale for previously reported disease-causing mutations, and a means for rational drug design against cardiovascular disease and obesity. In contrast to the previously reported structure of lipovitellin, which has a funnel-like lipid-binding cavity, the lipid-binding site is encompassed in a β-sandwich formed by 2 β-sheets from the C-terminal domain of MTPα. The lipid-binding cavity of MTPα is large enough to accommodate a single lipid. PDI independently has a major role in oxidative protein folding in the endoplasmic reticulum. Comparison of the mechanism of MTPα binding by PDI with previously published structures gives insights into large protein substrate binding by PDI and suggests that the previous structures of human PDI represent the “substrate-bound” and “free” states rather than differences arising from redox state.
MiR223-3p promotes synthetic lethality in BRCA1-deficient cancers
Authors: Srinivasan Gayathri , Williamson Elizabeth A. , Kong Kimi , Jaiswal Aruna S. , Huang Guangcun , Kim Hyun-Suk , Schärer Orlando , Zhao Weixing , Burma Sandeep , Sung Patrick , Hromas Robert
Published: August 2019

Significance

One origin of cancer arises from defects in the homologous recombination (HR) DNA repair pathway, which results in oncogenic genomic instability. Normal cells prefer HR for repair of stressed replication forks because it is highly conservative. The back-up pathway for repair of stressed replication forks, alternative non-homologous end-joining (aNHEJ), can result in chromosomal instability. Normal cells use microRNA (miR) 223-3p to down-regulate aNHEJ and thus promote HR, which protects genomic stability. However, those cancers that arise from inherited or acquired defects in HR components, such as the BRCA1 breast and ovarian cancers, silence miR223-3p to enhance aNHEJ repair of stressed replication forks. Reconstituting expression of miR223-3p in these cancers causes synthetic lethality, and is a potential therapeutic modality.
The complexity of farmworkers’ livelihoods in Zimbabwe after the Fast Track Land Reform: experiences from a farm in Chinhoyi, Zimbabwe
Authors: Kudzai Chiweshe Manase , Chabata Takunda
Published: August 2019

The Fast Track Land Reform programme in Zimbabwe was one of the largest land redistribution exercises in the world. The programme had varying impacts on the diverse rural population, leading to a binary projection of winners and losers. The authors use a micro case study of former farmworkers in Chinhoyi to highlight how this particular group has fared since 2000. The authors’ interest is in understanding how the programme impacted on the farmworkers’ livelihoods and how they have responded to the changing agrarian structure. The authors focus on the bulk of the permanent farmworkers on the A2 farms who remained in the farm compounds where they offered to work for the new black farm owners. Using qualitative methodology, this study assesses the fragile patterns of livelihoods for the resident farmworkers. The vast majority of these workers did not get land during the land reform programme, thus their livelihoods in large part derive from the labour they sell to their new employers. This livelihood option however remains limited, ephemeral and unreliable.
Contested histories and contested land claims: traditional authorities and the Fast Track Land Reform programme in Zimbabwe, 2000–2017
Authors: Dande Innocent , Mujere Joseph
Published: August 2019

This article analyses conflicts among traditional authorities over ancestral lands, and boundaries during and in the aftermath of Zimbabwe’s Fast Track Land Reform programme (FTLRP). It argues that the FTLRP gave a fresh impetus to conflicts over land and boundaries among traditional authorities as they sought to recast their authority into areas from which they were displaced during the colonial period. It further argues that land claims in the post-FTLRP period were often entangled with contestations over history and legitimacy as rival groups made use of oral traditions and archives to bolster their claims. Most of these struggles over land ended up being decided in the country’s court system. Overall, the article argues that struggles over land claims in the post-FTLRP period have largely ended up being struggles over versions of the history of land ownership and colonial displacements.
4-O-methylascochlorin stabilizes hypoxia-inducible factor-1 in a manner different from hydroxylase inhibition by iron chelating or substrate competition
Authors: Magae Junji , Furukawa Chiharu , Kuwahara Shigefumi , Jeong Yun-Jeong , Nakajima Hiroo , Chang Young-Chae
Published: August 2019

Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that plays essential roles in human diseases including cancer. The synthetic ascochlorin derivative 4-O-methylascochlorin stabilizes HIF-1α protein, and activates its transcriptional activity, resulting to induce gene expression of its downstream targets such as VEGF and GLUT-1. Here, we quantified protein level of HIF-1α in human osteosarcoma U2OS cells treated with ascochlorin-related compounds and typical HIF-1α stabilizers to characterize properties of HIF-1α stabilization by 4-O-methylascochlorin. Structure–activity relationship studies suggested that the aromatic moiety and hydrophobic substitution of the 4′-hydroxyl group are important for HIF-1α stabilization by ascochlorin-related compounds. 4-O-Methylascochlorin-induced HIF-1α stabilization was suppressed by ascorbic acid and compound C, but not by Fe(II), whereas ascorbic acid only suppressed HIF-1α stabilization by dimethyloxaloylglycine, an analog of the HIF-1 hydroxylase substrate. Fe(II) completely suppressed iron chelator-induced stabilization. These results suggest that ascochlorin-related compounds stabilize HIF-1α in a manner distinct from iron chelating or substrate competition.
Electronic cigarette exposure reduces exercise performance and changes the biochemical profile of female mice
Authors: Chen Yi-Ming , Huang Chi-Chang , Sung Hsin-Ching , Lee Mon-Chien , Hsiao Chien-Yu
Published: August 2019

Electronic cigarette(s) (EC) becoming a preferred replacement for nicotine delivery among many smokers in recent years. However, the effect of EC on human health is inconclusive due to a lack of empirical research investigating EC-induced health hazard or benefit. In this study, we examine the effect of vapor produced by EC on exercise performance and health-related profiles in a mouse model. Female ICR mice were divided into five groups (n = 6 per group) and exposed for 14 days. Our results indicate that EC exposure leads to dose-dependent decrease in the grip strength and swimming time of the mice. The EC-treated groups also showed a dose-dependent decrease in liver and muscle glycogen storage. In addition, EC treatment had no negative effect on levels of biochemical indices. We also did not detect any adverse effect or gross abnormalities on the morphology of the major organs.
Chromatin compartment dynamics in a haploinsufficient model of cardiac laminopathy
Authors: Bertero Alessandro , Fields Paul A. , Smith Alec S.T. , Leonard Andrea , Beussman Kevin , Sniadecki Nathan J. , Kim Deok-Ho , Tse Hung-Fat , Pabon Lil , Shendure Jay , Noble William S. , Murry Charles E.
Published: August 2019

Mutations in A-type nuclear lamins cause dilated cardiomyopathy, which is postulated to result from dysregulated gene expression due to changes in chromatin organization into active and inactive compartments. To test this, we performed genome-wide chromosome conformation analyses in human induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs) with a haploinsufficient mutation for lamin A/C. Compared with gene-corrected cells, mutant hiPSC-CMs have marked electrophysiological and contractile alterations, with modest gene expression changes. While large-scale changes in chromosomal topology are evident, differences in chromatin compartmentalization are limited to a few hotspots that escape segregation to the nuclear lamina and inactivation during cardiogenesis. These regions exhibit up-regulation of multiple noncardiac genes including CACNA1A, encoding for neuronal P/Q-type calcium channels. Pharmacological inhibition of the resulting current partially mitigates the electrical alterations. However, chromatin compartment changes do not explain most gene expression alterations in mutant hiPSC-CMs. Thus, global errors in chromosomal compartmentation are not the primary pathogenic mechanism in heart failure due to lamin A/C haploinsufficiency.
Quantum kinetic perturbation theory for near-integrable spin chains with weak long-range interactions
Authors: Duval Clément , Kastner Michael
Published: August 2019

For a transverse-field Ising chain with weak long-range interactions we develop a perturbative scheme, based on quantum kinetic equations, around the integrable nearest-neighbour model. We introduce, discuss, and benchmark several truncations of the time evolution equations up to eighth order in the Jordan–Wigner fermionic operators. The resulting set of differential equations can be solved for lattices with O(102) sites and facilitates the computation of spin expectation values and correlation functions to high accuracy, at least for moderate timescales. We use this scheme to study the relaxation dynamics of the model, involving prethermalisation and thermalisation. The techniques developed here can be generalised to other spin models with weak integrability-breaking terms.
An analysis of students’ literacy ability in mathematics teaching with realistic mathematics education based on lesson study for learning community
Authors: Rohman Syaifur , Susanto  , Hobri  , Saiful  , Sahnawi
Published: August 2019

The aims of this research is to explore students’ literation abilities descriptively and teacher’s response in Math instruction of lesson study for learning community based realistic mathematics education. Literation ability is the ability of the individual to form, use, and interpret mathematics in various contexts. Realistic mathematics education aims to present the real world context to students. The research subjects were 29 seventh grade students of MTs Ma’arif Ambulu. The descriptive approach of qualitative method becomes a choice to understand literation ability and teachers’ response. Data collection was done by observation, PISA test questions, student and teacher interviews, and documentation. Data analysis was using the theory of induction and reduction. The results of the research showed that the students were positively responding to this approach. The ratios of mathematical literacy ability based on the total students respectively were 44.83% on level 4 and 31.03% on level 5, and 24.14% on level 3. The teacher’s response showed that this approach could change the atmosphere to be more active between the teacher and the students as well as the students with their fellow. The teacher could optimize his role; recognize his weakness through reflection with the team so that he had the opportunity to prepare the next strategy to improve quality.
Analysis of students’ attitudes towards implementation of geogebra-assisted missouri mathematics project
Authors: Rosyid Abdul , Umbara Uba
Published: August 2019

This article aims to examine in depth the students’ attitudes towards the implementation of Geogebra-assisted Missouri Mathematics Project. This research was conducted at junior high school 4 Kuningan. This study uses a survey method. In this study, the survey was conducted on 31 students who obtained the GeoGebra-assisted Missouri Mathematics Project (MMP) learning model using a Likert scale questionnaire consisting of 20 statement items. Furthermore, students’ attitude questionnaire data was analyzed in quantitative descriptive and a priori calculations for use in interpreting the research data later. The results of the students’ attitudes data analysis showed the average percentage of respondents’ answers as a whole was 66.59%. It means that most students have a positive attitude towards learning from the GeoGebra-assisted Missouri Mathematics Project. The results of the attitude data analysis also showed that the average students’ attitude was 3.12 greater than the neutral attitude of 2.5. It means that students have a positive attitude towards GeoGebra-assisted Missouri Mathematics Project. From the various analyzes, the results of the study showed that students have a positive attitude towards the implementation of GeoGebra-assisted Missouri Mathematics Project.