bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐gain, high‐isolation, and wideband millimetre‐wave closely spaced multiple‐input multiple‐output antenna with metamaterial wall and metamaterial superstrate for 5G applications
Authors: Khajeh‐Khalili Farzad , Honarvar Mohammad Amin , Naser‐Moghadasi Mohammad , Dolatshahi Mehdi 
Published: March 2021

AbstractA method to significantly increase the gain and isolation of a wideband multiple‐input multiple‐output (MIMO) antenna using metamaterial structures is reported. The proposed metamaterial medium includes just one wall and one superstrate, which are fixed in xz and xy planes of the MIMO antenna, respectively. The dimensions of the proposed MIMO antenna are 13×13×3.5 mm3 at 30 GHz. A comparison between a simulated MIMO antenna and a conventional microstrip antenna demonstrates the good performance of the proposed metamaterial environment. The corresponding return‐loss of the antenna is better than 10 dB over 28–32 GHz for 5G applications. The maximum simulated gain of the antenna is 17.1 dB at 30 GHz, generating a maximum gain enhancement of 11.8 dB in comparison with a MIMO antenna without any metamaterial structures. The isolation (insertion‐loss) is 36.7 dB at 30 GHz, which has improved by more than 29.4 dB compared to the conventional one.
High gain and wideband patch antenna with wide 3‐dB axial ratio bandwidth operating at TM01 and TM11 modes
Authors: Fakhte Rasoul , Aryanian Iman 
Published: March 2021

AbstractA wideband and high gain circularly polarised patch antenna has been introduced. The proposed antenna combines an aperture coupled feeding with a T‐slot, four metallic vias and a patch with a diagonal slot to present high gain and wide 3‐dB axial ratio bandwidth (BW) characteristics. In this study, a rectangular patch (0.6 λ0 × 0.5 λ0 at f = 7.5 GHz) with a diagonal slot has been symmetrically located above the T‐slot at the height of 0.07 λ0. A WR90 waveguide with the length of 50 mm and a T‐slot in its extended outer wall has been used as a primary antenna that feeds the patch element. Four metallic vias with shunt inductive effects have been used to virtually enlarge radiating patch dimension, so they present a significant improvement in antenna gain, BW and axial ratio. The proposed antenna shows the BW of 30% with tgain of up to 12 dBi and an axial ratio BW of 21%. Due to its wideband, high gain, and wide 3‐dB axial ratio BW, this antenna is a good candidate for some applications, such as small satellites, and for the global positioning system the high gain, precision and flexibility of the system are crucial.
Electron-impact excitation of Ni II
Authors: Dunleavy N. L. , Ramsbottom C. A. , Ballance C. P. 
Published: March 2021

Aims. Energy levels, transition probabilities, and oscillator strengths are calculated for the second most abundant iron peak element Ni II. The difficulty in obtaining an accurate target representation is related to the open d-shell nature of the target, which has a minimum requirement of single and double promotions from the ground state configuration to the n = 4 shells. Therefore, in order to achieve an accurate representation of the target ion, we have also included configurations containing the 4d, 5s, and 5p subshells. We have undertaken a study of the electron impact excitation of Ni II and present here the collision strengths for forbidden and allowed transitions among the lowest 800 fine-structure levels as well as the corresponding Maxwellian-averaged effective collision strengths for a range of astrophysically relevant electron temperatures.
Methods. An accurate Ni II target structure was generated using the modified General-purpose Relativistic Atomic Structure Package (GRASP0) for the lowest lying 1220 jj fine-structure levels, comprising the 11 configurations: 3p63d9, 3p63d84s, 3p63d84p, 3p63d84d, 3p63d85s, 3p63d85p, 3p63d74s2, 3p63d75s2, 3p63d74s4p, 3p63d74s4d, and 3p43d94s4d. The relativistic parallel Dirac atomic R-matrix codes (DARC) were utilised in the scattering calculations to generate the collision strengths for incident electron energies between 0 and 2 Ryd and, by employing infinite dipole and non-dipole limit points, we also generated the effective collision strengths for temperatures in the range from 1000 to 400 000 K. Two separate calculations were performed, both comprised of truncated close-coupling expansions of 800 jj-levels with the first calculation retaining the theoretical ab initio energy levels generated in the GRASP0 evaluations, whereas in the second calculation these energies were shifted to their predicted National Institute of Standards and Technology (NIST) values where possible. This should provide a lower estimate on the uncertainty.
Results. Comparisons are made between the radiative data and the collisional cross sections with past theoretical and experimental studies. The effective collision strengths when compared with the most recent published calculations, are found to agree to within 10% for the majority of the transitions considered. In addition, the data are used to model the spectrum of Ni II and good agreement is found with previous investigations and observations.
Revisiting the Spleen—An Imaging Review of the Common and Uncommon Splenic Pathology
Authors: Nadeem Meshaal , Tiwari Hina Arif , Jambhekar Kedar , Shah Hemendra , Ram Roopa 
Published: March 2021

AbstractThe spleen is the largest lymphatic organ and is responsible for both hematological and immunological functions. Several common etiologies such as trauma, developmental variants, infectious/inflammatory conditions, and benign and malignant lesions can occur in the spleen. The role of imaging modalities such as ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) in diagnosing these conditions continues to evolve. The main objective of this review article is to illustrate the role of imaging in identifying the common and uncommon pathology of the spleen.
Orbital Surgical Guidelines—Clinical Evaluation
Authors: Krauss Howard R. 
Published: March 2021

AbstractOrbital disorders may present with change in form or function or may be discovered incidentally during clinical or imaging evaluations. A standardized orbital clinical examination, with appropriate ancillary tests, is helpful in narrowing the differential diagnosis and in the development of plans for management, with an eye toward minimizing the morbidity of the disease or its treatment. Evaluation and management may best be performed with a multidisciplinary team, which has become more common in skull base surgery.
Incoherent Thomson scattering system for PHAse space MApping (PHASMA) experiment
Authors: Shi Peiyun , Srivastav Prabhakar , Beatty Cuyler , Nirwan Ripudaman Singh , Scime Earl E. 
Published: March 2021

A new incoherent Thomson scattering system measures the evolution of electron velocity distribution functions perpendicular and parallel to the ambient magnetic field during kinking of a single flux rope and merging of two flux ropes through magnetic reconnection. The Thomson scattering system provides sub-millimeter spatial resolution, sufficient to diagnose the several millimeters sized magnetic reconnection electron diffusion region in the PHAse Space MAppgin experiment. Due to the relatively modest plasma density ∼1019 m−3 and electron temperature ∼1 eV, stray light suppression is critical for these measurements. Two volume Bragg gratings are used in series as a notch filter with a spectral bandwidth &lt;0.1 nm in the collection branch. A CCD with a Gen III intensifier with peak quantum efficiency &gt;47% is used as the detector in a 1.3 m spectrometer. Preliminary results of gun plasma electron temperature will be reported and compared with measurements obtained from a triple Langmuir probe.
A cartographic approach to sentence production in aphasia
Authors: Wang Haiyan , Liu Xinmiao , Li Xin 
Published: March 2021

AbstractThere is much evidence that individuals with aphasia (IWA) are impaired in tense or aspectual inflections and the production of non-canonical sentences like passives. On the Cartographic Approach (CA), passives are represented at the lower node in the syntactic tree, with tense or aspectual elements at the higher node. This hierarchical structure can be used to account for the selective impairments in aphasic production. The present study reports the empirical findings from Chinese agrammatism using the theory of cartography. It is found that the performance of IWA with different degrees of severity is associated with different nodes (CP, TP, and vP) in the syntactic tree. Notably, the Chinese-speaking IWA are severely impaired in vP-related elements. Finally, the present study highlights the significance of adopting a cartographic approach to aphasia studies.
A note on the vacuum structure of lattice Euclidean quantum gravity: ‘birth’ of macroscopic space-time and PT-symmetry breaking
Authors: Vergeles S N 
Published: March 2021

Abstract
It is shown that the ground state or vacuum of the lattice quantum gravity is significantly different from the ground states of the well-known vacua in QED, QCD, et cetera. In the case of the lattice quantum gravity, the long-wavelength scale vacuum structure is similar to that in QED, moreover the quantum fluctuations of gravitational degrees of freedom are very reduced in comparison with the situation in QED. But the small scale (of the order of the lattice scale) vacuum structure in gravity is significantly different from that in the long-wavelength scales: the fluctuation values of geometrical degrees of freedom (tetrads) are commensurable with theirs most probable values. It is also shown that the macroscopic Universe can exist only in the presence of fermion fields. In this case, spontaneous breaking of the PT symmetry occurs.
Laboratory calibration for multidirectional spectroradiometers
Authors: Niedzwiedz Angelika , Duffert Jens , Tobar-Foster Mario , Quadflieg Esther , Seckmeyer Gunther 
Published: March 2021

Abstract
A method for the calibration of multidirectional spectroradiometers (MUDISs) capable of the simultaneous measurement of spectral radiance at different wavelengths is presented. The calibration of the spectroradiometer is challenging and crucial for high quality measurements of the angular dependence of the radiance. The calibration device consists of an integrating sphere (also known as Ulbrichtkugel), with a diameter of 100 cm, equipped with three 100 W lamps positioned in the lower hemisphere, with the input optics of the MUDIS directed towards the upper hemisphere. The MUDIS detects radiation from 113 different directions simultaneously in a wavelength range from 300 nm to 550 nm. Due to multiple reflections within the sphere, the radiance from the upper hemisphere is nearly homogeneous with deviations of less than 3% on average. Disregarding the 3% variability and assuming a homogeneous radiance inside the upper hemisphere of the integrating sphere, the spectral responsivities of all the MUDIS channels were determined based on the measured zenith radiance, which was detected by a pre-calibrated Network for the Detection of Atmospheric Composition Change reference spectroradiometer containing a scanning double monochromator with a unidirectional input optics. The input optics of the MUDIS contains thin fibers that should not be moved to avoid changes in the instrument’s responsivity. The proposed method is therefore suited to determine the absolute responsivity of the MUDIS for all directions.
A portable triaxial cell for beamline imaging of rocks under triaxial state of stress
Authors: Syed Amer , Tanino Yukie , LaManna Jacob M , Jacobson David L , Hussey Daniel S , Baltic Eli , Burca Genoveva 
Published: March 2021

Abstract
With recent developments in direct imaging techniques using x-ray and neutron imaging, there is an increasing need for efficient test setups to study the mechanical and/or transport behavior of porous rocks. Bespoke designs from commercial suppliers are expensive and often difficult to modify. This paper presents a novel design of a portable triaxial cell for imaging deformation (and a suggested adaptation to introduce fluid transport) through rocks/sand/soil under the triaxial states of stress representative of those encountered in the case of groundwater aquifers or subsurface hydrocarbon reservoirs. The design philosophy and the parameters are detailed so that interested researchers can use this experimental setup as a template to design and modify triaxial cells to suit their own experimental requirements. The design has been used in two imaging beamlines: Imaging and Material Science & Engineering (IMAT), ISIS facility, Harwell, Oxfordshire, UK, and BT2 of the National Institute of Standards and Technology Center for Neutron Research, Gaithersburg, MD, USA. The mass attenuation coefficients extracted from the 2D radiograms of the triaxial cell were compared with those reported in the literature. Further suggestions for the adaptation of the triaxial cells for studying the mechanics of deformation and fracture in rocks are included.
An automated optimization strategy to design collimator geometry for small field radiation therapy systems
Authors: Wang Jinghui , Wang Lei , Maxim Peter G , Loo Billy W 
Published: March 2021

Abstract

Purpose. To develop an automated optimization strategy to facilitate collimator design for small-field radiotherapy systems. Methods and Materials. We developed an objective function that links the dose profile characteristics (FWHM, penumbra, and central dose rate) and the treatment head geometric parameters (collimator thickness/radii, source-to-distal-collimator distance (SDC)) for small-field radiotherapy systems. We performed optimization using a downhill simplex algorithm. We applied this optimization strategy to a linac-based radiosurgery system to determine the optimal geometry of four pencil-beam collimators to produce 5, 10, 15, and 20 mm diameter photon beams (from a 6.7 MeV, 2.1 mm FWHM electron beam). Two different optimizations were performed to prioritize minimum penumbra or maximum central dose rate for each beam size. We compared the optimized geometric parameters and dose distributions to an existing clinical system (CyberKnife). Results. When minimum penumbra was prioritized, using the same collimator thickness and SDC (40 cm) as a CyberKnife system, the optimized collimator upstream and downstream radii agreed with the CyberKnife system within 3%–14%, the optimized output factors agreed within 0%–8%, and the optimized transverse and percentage depth dose profiles matched those of the CyberKnife with the penumbras agreeing within 2%. However, when maximum dose rate was prioritized, allowing both the collimator thickness and SDC to change, the central dose rate for larger collimator sizes (10, 15, 20 mm) could be increased by about 1.5–2 times at the cost of 1.5–2 times larger penumbras. No further improvement in central dose rate for the 5 mm beam size could be achieved. Conclusions. We developed an automated optimization strategy to design the collimator geometry for small-field radiation therapy systems. Using this strategy, the penumbra-prioritized dose distribution and geometric parameters agree well with the CyberKnife system as an example, suggesting that this system was designed to prioritize sharp penumbra. This represents proof-of-principle that an automated optimization strategy may apply to more complex collimator designs with multiple optimization parameters.
Non-linear thermal resistance model for the simulation of high power GaN-based devices
Authors: García-Sánchez S , Íñiguez-de-la-Torre I , Pérez S , Ranjan K , Agrawal M , Lingaparthi R , Nethaji D , Radhakrishnan K , Arulkumaran S , Ng G I , González T , Mateos J 
Published: March 2021

Abstract
We report on the modeling of self-heating in GaN-based devices. While a constant thermal resistance is able to account for the self-heating effects at low power, the decrease of the thermal conductance of semiconductors when the lattice temperature increases, makes necessary the use of temperature dependent thermal resistance models. Moreover, in order to correctly account for the steep increase of the thermal resistance of GaN devices at high temperature, where commonly used models fail, we propose a non-linear model which, included in an electro-thermal Monte Carlo simulator, is able to reproduce the strongly non-linear behavior of the thermal resistance observed in experiments at high DC power levels. The accuracy of the proposed non-linear thermal resistance model has been confirmed by means of the comparison with pulsed and DC measurements made in devices specifically fabricated on doped GaN, able to reach DC power levels above 150 W mm−1 at biases below 30 V.
Autologous Fat Transplantation for Aesthetic Breast Augmentation: A Systematic Review and Meta-Analysis
Authors: Wu Yingjie , Hu Feng , Li Xueping , Yin Guoqian 
Published: March 2021

Abstract

Background
Autologous fat transplantation has already become a part of clinical practice for aesthetic breast augmentation even though evidence regarding its efficacy is still lacking.

Objectives
The authors sought to determine the current worldwide status and efficacy, techniques, and oncologic safety on this subject.

Methods
PubMed, EMBASE, and Cochrane Library databases were searched to identify all relevant studies.

Results
Eighty-four articles published between 1987 and April 2020, consisting of 6468 patients, were included, and 64 studies consisting of 5162 unique patients were included in the meta-analysis. Most studies had a low level of evidence (levels 2b-5); In this meta-analysis, there were 17 prospective cohort studies, 4 retrospective cohort studies, 6 case-control studies, and 38 case series. The publications were from 21 countries. Indications for autologous fat transplantation were aesthetic augmentation (93.2%) and congenital malformation (6.8%). Among the 5162 patients, 2 cases (0.04%) of cancer were reported. The meta-analysis revealed very high overall patient and surgeon satisfaction rates of 93% and 87%, respectively. Overall, only 1.56 sessions were needed to achieve the desired result. Long-term survival was calculated to be approximately 60% to 70% at 1-year follow-up. Only 8% of procedures resulted in clinical complications, and 5% of patients required biopsy because of abnormal clinical or radiological findings.

Conclusions
Autologous fat transplantation seems to be a major tool in aesthetic breast augmentation. Preoperative patient selection is essential but under-reported. Future research should focus on evaluating the technical and patient factors influencing the rate of fat survival and its oncological safety.

Level of Evidence: 4
Subcutaneous Face and Neck lift: A Traditional Method With Definite Effects Among Asians
Authors: Wang Guanhuier , Zhao Runlei , Bi Ran , Xie Hongbin 
Published: March 2021

Abstract

Background
The mainstream facelifts in Western countries always involve the superficial fascia/superficial musculoaponeurotic system treatment. Meanwhile, subcutaneous face and neck lifts are widely applied among Asians.

Objectives
The authors sought to evaluate outcomes of subcutaneous face and neck lift, including patient-reported and 3-dimensional (3D) measurement outcomes, and report on details of surgical procedures.

Methods
Patients who received a subcutaneous face and neck lift from January 2017 to June 2019 were asked to complete FACE-Q scales, and facial information was collected by the Vectra 3D imaging system preoperatively and postoperatively. Volume changes in midface and possible displacement of facial landmarks were measured. The range of dissection and the amount of skin removed were recorded intraoperatively.

Results
In total, 119 patients (median age, 46 years, interquartile range, 40-53 years) received a subcutaneous face and neck lift. Among them, 88 patients completed pre- and postoperative FACE-Q scales. Patients’ satisfaction with facial subunits improved and wrinkles were significantly relieved (P &lt; 0.001). Nineteen patients (38 midface sides) completed 3D image data collection. Postoperatively, zygomatic volume increased, and nasolabial and lateral cheek volumes decreased (volume change of 2.2 ± 1.3 mL). Mouth, nose, and eye displacements were negligible postoperatively. The widths of skin removed at the middle temporal, front of the sideburns, upper helix, earlobe, and retro-auricular were 13.8 ± 1.9 mm, 19.6 ± 3.1 mm, 27.6 ± 3.9 mm, 16.4 ± 3.9 mm, and 32.2 ± 4.0 mm, respectively.

Conclusions
The authors’ subcutaneous face and neck lift was effective in relieving nasolabial sagging, improving wrinkles, and achieving facial rejuvenation.

Level of Evidence: 4
Measuring Instruments for Empowerment in Social Work: A Scoping Review
Authors: Noordink Thomas , Verharen Lisbeth , Schalk René , van Eck Marcel , van Regenmortel Tine 
Published: March 2021

AbstractEmpowerment is seen as an important thinking and working framework for social work. Ideally, it is possible to measure the empowering effects of social work. However, various factors complicate measuring empowerment, making it a difficult exercise. In past decades many instruments for measuring empowerment have been developed and there are many variations in the way these instruments have been developed. The aim of this review is to provide a comprehensive overview of the available instruments, scales or questionnaires that intent to measure the empowerment of users of social work in different contexts of social work, by means of a scoping review. A total of 2,711 studies were screened, resulting in 49 unique instruments for measuring empowerment in contexts related to social work. The results show that the found instruments are almost exclusively Patient-Reported Outcome Scales. Whilst many instruments measure individual empowerment, only a few measure community empowerment. The results also show that there are many variations in which instruments operationalise empowerment. This overview provides social work organisations and its researchers an overview of measuring tools necessary to measure the effects of their efforts, allowing them to build on what is available.
Disruption of the blood–brain barrier in 22q11.2 deletion syndrome
Authors: Crockett Alexis M , Ryan Sean K , Vásquez Adriana Hernandez , Canning Caroline , Kanyuch Nickole , Kebir Hania , Ceja Guadalupe , Gesualdi James , Zackai Elaine , McDonald-McGinn Donna , Viaene Angela , Kapoor Richa , Benallegue Naïl , Gur Raquel , Anderson Stewart A , Alvarez Jorge I 
Published: March 2021

AbstractNeuroimmune dysregulation is implicated in neuropsychiatric disorders including schizophrenia. As the blood−brain barrier is the immunological interface between the brain and the periphery, we investigated whether this vascular phenotype is intrinsically compromised in the most common genetic risk factor for schizophrenia, the 22q11.2 deletion syndrome (22qDS). Blood−brain barrier like endothelium differentiated from human 22qDS+schizophrenia-induced pluripotent stem cells exhibited impaired barrier integrity, a phenotype substantiated in a mouse model of 22qDS. The proinflammatory intercellular adhesion molecule-1 was upregulated in 22qDS+schizophrenia-induced blood–brain barrier and in 22qDS mice, indicating compromise of the blood–brain barrier immune privilege. This immune imbalance resulted in increased migration/activation of leucocytes crossing the 22qDS+schizophrenia blood−brain barrier. We also found heightened astrocyte activation in murine 22qDS, suggesting that the blood−brain barrier promotes astrocyte-mediated neuroinflammation. Finally, we substantiated these findings in post-mortem 22qDS brain tissue. Overall, the barrier-promoting and immune privilege properties of the 22qDS blood–brain barrier are compromised, and this might increase the risk for neuropsychiatric disease.