Mirror Image Research Articles

Indoor Environment Learning via RF-Mapping

Intelligent integrated sensing and communication is one of key aspects of future wireless networks in which sensing can be leveraged to enhance communications and vice-versa. In this paper, we propose a novel sensing solution that can be used to represent an RF-environment. The proposed solution accounts for practical challenges such as limited time resolution due to limited bandwidth with no angle measurements while providing robustness to wireless propagation phenomena such as diffraction. Our proposed method leverages offline data collection during RF-mapping, and finds the location of virtual anchors (VAs), i.e., mirror images of a physical anchor w.r.t reflectors, through an iterative process called successive tap removal (STR). Afterwards, machine learning (ML) models are trained to predict dominant multipath components of the received wireless channel at a given location. Found VAs and their associated ML models stand for intermediate entities that represent an RF-environment. As an application, we use the developed models in the context of multipath assisted positioning to improve positioning accuracy in challenging indoor environments with heavy non-line-of-sight (NLoS) conditions. Finally, we extend our ideas to systems with multi-antenna transmitters and show that VA detection accuracy can be improved, bringing higher accuracy to the downstream positioning applications.

Using a smartphone three dimensional scanning application (Polycam) to three dimensionally print an ear cast: A technique

This technique describes the use of a smartphone application for scanning an ear for 3-dimensional (3D) printing of an auricular prosthesis cast. The intact ear was scanned by using a smartphone and a 3D scan application (Polycam). The standard tessellation language (STL) file of the 3D data was used to produce a mirror image of the ear, which was sent to the 3D printing center where a resin cast was printed. This technique is harmless for the patient compared with radiological imaging methods, more comfortable, and cost-effective and is straightforward for the maxillofacial prosthodontist.

Formed developables - a new class of sheet metal parts

Sheet metal parts are broadly classified as stamped parts versus folded developables. While stamped parts are parts manufactured using conventional sheet metal forming techniques, folded developables are curved developable connections produced by the virtue of the classical theory of folded developables. However, folding is not suitable for parts where material integrity cannot be compromised at the fold lines. In such cases, forming techniques can be used to introduce a distributed curvature and avoid material self-intersection at the curved fold axis. This paper combines the two genres to introduce a third class of parts called the formed developables. A developable shaped, thin sheet metal of very high strength and reasonable inextensibility is formed by flange drawing over a die radius. The die tool establishes the required curved bend axis, and the die radius is small enough to introduce a distributed curvature. A developable connection is successfully formed where the two connected corrugations are mirror images of each other. While no tearing or wrinkling is observed, experimental strain measurements highlight significant surface strains in the transverse direction while marginal stretching strains are observed in the forming direction. A trend of equal and opposite transverse strains strongly suggests that the major deformation in this geometrical process, and in-turn the shape of the final part, is driven by the involved geometrical parameters.

The reflection invariance problems in stereochemical nomenclature for absolute configuration

Abstract Genesis of chirality and its link to the origin of life continue to intrigue scientists. Chirality also plays an important role in medicine with the advent of chiral drugs and the consequent importance of asymmetric synthesis. The configuration of a chiral molecule gets inverted in its mirror image, as is manifested by (i) sign of specific rotation and (ii) normally, through the absolute configurational notation (R/S). While the first parameter is always true, the second one, that is the mirror image relationship of R and S configurations, called the reflection variance, may not always hold good. In this manuscript, we have highlighted examples of molecules with combinations of central and axial or planar chirality where the mirror image relationship between R and S configurations does not hold. This reflection invariance originates from the CIP rule of R precedes S. Similar reflection invariance can be observed in P or M forms of conformations of some particular molecules with chiral ligands. Proposal to avoid such reflection invariances, has been put forward. An ignorance about the possibility of reflection invariance in enantiomeric molecules can lead to common mistakes about stereoisomeric relationship or reactivity profile.

Segmentation of the 3D printed mirror image auricular model to ease sculpture of the costal cartilages in total auricular aesthetic reconstruction

BackgroundRecently, three-dimensional (3D) models have been used more frequently than the traditional two-dimensional (2D) models as an intraoperative guide to ease sculpture of costal cartilages in total auricular aesthetic reconstruction in cases of microtia. Usually, 3D imaging techniques are used to create compact ear models, however, there is insufficient clinical knowledge of using them to create segmented 3D auricular models for cartilage framework reconstruction. In this studyassessment of the advantages of segmentation of 3D models over the traditional compact 3D models in total auricular aesthetic reconstruction has been discussed. Patients and methodsIn the current study, 16 patients who underwent total auricular aesthetic reconstruction using 3D models were included, patients were divided into two groups (Group I, 8 patients had total auricular aesthetic reconstruction using compact 3D printed mirror image model). Whereas (Group II, 8 patients had total auricular aesthetic reconstruction using segmented 3D printed mirror image model into auricular subunits. Then, each subunit was used for reconstruction of the corresponding part of the auricle. In both groups the patient's unaffected ear was mirrored and used as a reference to reconstruct the affected side. ResultsThe results were evaluated in both groups. The overall operative and carving times were found to be less in Group II; Also, postoperative aesthetic outcome and patient satisfaction were favorable in this group. ConclusionUsing segmentation of 3D printed models in total auricular aesthetic reconstruction had less intraoperative time, better aesthetic results, and high postoperative patient satisfaction.

The momentum distributions of triatomic molecular ion by intense laser pulses

We investigate theoretically the photoionization of triatomic molecular ion by numerically solving the two-dimensional time-dependent Schrödinger equations under Bohn-Oppenheimer approximation. The results show that the photoelectron momentum distributions (PMDs) of with different initial states are strongly dependent on the laser ellipticities and molecular orbital symmetry, and the PMDs of degenerate electronic states E ± are mirror images. Also, for degenerate electronic states E ±, vortex structures appear in the PMDs by the counter-rotating circularly polarized laser pulses as the time delay between the two pulses increases, which can be explained by multi-center ionization and ultrafast photoionization model.

The Digital Twin: A Potential Solution for the Personalized Diagnosis and Treatment of Musculoskeletal System Diseases.

Due to the high prevalence and rates of disability associated with musculoskeletal system diseases, more thorough research into diagnosis, pathogenesis, and treatments is required. One of the key contributors to the emergence of diseases of the musculoskeletal system is thought to be changes in the biomechanics of the human musculoskeletal system. However, there are some defects concerning personal analysis or dynamic responses in current biomechanical research methodologies. Digital twin (DT) was initially an engineering concept that reflected the mirror image of a physical entity. With the application of medical image analysis and artificial intelligence (AI), it entered our lives and showed its potential to be further applied in the medical field. Consequently, we believe that DT can take a step towards personalized healthcare by guiding the design of industrial personalized healthcare systems. In this perspective article, we discuss the limitations of traditional biomechanical methods and the initial exploration of DT in musculoskeletal system diseases. We provide a new opinion that DT could be an effective solution for musculoskeletal system diseases in the future, which will help us analyze the real-time biomechanical properties of the musculoskeletal system and achieve personalized medicine.

Chiral Materials: Progress, Applications, and Prospects.

Chirality is a universal phenomenon in molecular and biological systems, denoting an asymmetric configurational property where an object cannot be superimposed onto its mirror image by any kind of translation or rotation, which is ubiquitous on the scale from neutrinos to spiral galaxies. Chirality plays a very important role in the life system. Many biological molecules in the life body show chirality, such as the "codebook" of the earth's biological diversity-DNA, nucleic acid, etc. Intriguingly, living organisms hierarchically consist of homochiral building blocks, for example, l-amino acids and d-sugars with unknown reason. When molecules with chirality interact with these chiral factors, only one conformation favors the positive development of life, that is, the chiral host environment can only selectively interact with chiral molecules of one of the conformations. The differences in chiral interactions are often manifested by chiral recognition, mutual matching, and interactions with chiral molecules, which means that the stereoselectivity of chiral molecules can produce changes in pharmacodynamics and pathology. Here, the latest investigations are summarized including the construction and applications of chiral materials based on natural small molecules as chiral source, natural biomacromolecules as chiral sources, and the material synthesized by design as a chiral source.

Impact on the trachea in children with prenatally diagnosed vascular ring formed by a right aortic arch.

There has been a rise in the prenatal detection of right sided aortic arch (RAA). When associated with a left-sided arterial duct (LD), this forms a vascular ring encircling the trachea. Infants may have symptoms or signs suggestive of tracheoesophageal compression but many are asymptomatic. The objective of this study was to investigate the relationship between symptoms and severity of tracheobronchial compression assessed by bronchoscopy. Retrospective review of all cases of prenatally diagnosed RAA-LD in the absence of associated congenital heart disease at Evelina London Children's Hospital and Kings College Hospital over a 4-year period between April 2015-2019. Clinical records, fetal echocardiograms, and free-breathing flexible bronchoscopy (FB) data were reviewed. One hundred and twelve cases of isolated RAA-LD were identified of whom 82 cases (73%) underwent FB. FB was performed median age of 11 months (range 1-36 months), no complications occurred. Aberrant left subclavian artery (ALSA) was present in 86% (96/112) and mirror image branching (MIB) in 13% (15/112). 34/112 (30%) reported symptoms during follow-up. 36/77 (47%) with ALSA who underwent FB showed moderate-severe compression mostly at distal tracheal and carinal level of whom 38% had parent-reported symptoms. Moderate-severe compression was seen in 3/5 (60%) with MIB mostly at mid tracheal level; 3 were symptomatic but only 2 had tracheal compression. In total 36% (18/50) of investigated asymptomatic patients showed moderate-severe compression. Respiratory symptoms were poorly predictive of moderate-severe tracheal compression (positive predictive value 66%, negative predictive value 64%). The absence of symptoms did not exclude significant tracheal compression. The anatomical effect of the vascular ring is under appreciated when symptoms alone are used as a marker of tracheal compression.

Tunable THz dielectric resonator-graphene based dual port radiator with circular polarization and beam tilting features

In this article, a hybrid (dielectric resonator–graphene) MIMO antenna is presented and investigated at THz frequency. The unique properties associated with this antenna design are (i) CP waves are generated with the help of stair-shaped slot excitation; (ii) change in chemical potential of graphene creates the tunability in the proposed design structure; (iii) use of the metallic wall in between the antenna ports slants the far-field pattern by ± 30 deg, providing pattern diversity; and (iv) mirror image of the aperture introduces the concept of polarization diversity. The proposed antenna works between 4.65 and 5.71 THz with CP waves in between 5.25 and 5.5 THz. Polarization and pattern diversity help to improve the diversity performance of designed antenna. Good gain value and stable radiation pattern make the proposed antenna suitable for THz sensing applications.

Probing Molecular Chirality on the Self-Assembly and Gelation of Naphthalimide-Conjugated Dipeptides.

In this work, 1,8-naphthalimide (NMI)-conjugated three hybrid dipeptides constituted of a β-amino acid and an α-amino acid have been designed, synthesized, and purified. Here, in the design, the chirality of the α-amino acid was varied to study the effect of molecular chirality on the supramolecular assembly. Self-assembly and gelation of three NMI conjugates were studied in mixed solvent systems [water and dimethyl sulphoxide (DMSO)]. Interestingly, chiral NMI derivatives [NMI-βAla-lVal-OMe (NLV) and NMI-βAla-dVal-OMe (NDV)] formed self-supported gels, while the achiral NMI derivative [NMI-βAla-Aib-OMe, (NAA)] failed to form any kind of gel at 1 mM concentration and in a mixed solvent (70% water in DMSO medium). Self-assembly processes were thoroughly investigated using UV-vis spectroscopy, nuclear magnetic resonance (NMR), fluorescence, and circular dichroism (CD) spectroscopy. A J-type molecular assembly was observed in the mixed solvent system. The CD study indicated the formation of chiral assembled structures for NLV and NDV, which were mirror images of one another, and the self-assembled state by NAA was CD-silent. The nanoscale morphology of the three derivatives was studied using scanning electron microscopy (SEM). In the case of NLV and NDV, left- and right-handed fibrilar morphologies were observed, respectively. In contrast, a flake-like morphology was noticed for NAA. The DFT study indicated that the chirality of the α-amino acid influenced the orientation of π-π stacking interactions of naphthalimide units in the self-assembled structure that in turn regulated the helicity. This is a unique work where molecular chirality controls the nanoscale assembly as well as the macroscopic self-assembled state.

Measurement of parity-odd modes in the large-scale 4-point correlation function of Sloan Digital Sky Survey Baryon Oscillation Spectroscopic Survey twelfth data release CMASS and LOWZ galaxies

ABSTRACT A tetrahedron is the simplest shape that cannot be rotated into its mirror image in three-dimension (3D). The 4-point correlation function (4PCF), which quantifies excess clustering of quartets of galaxies over random, is the lowest order statistic sensitive to parity violation. Each galaxy defines one vertex of the tetrahedron. Parity-odd modes of the 4PCF probe an imbalance between tetrahedra and their mirror images. We measure these modes from the largest currently available spectroscopic samples, the 280 067 luminous red galaxies (LRGs) of the Baryon Oscillation Spectroscopic Survey (BOSS) twelfth data release (DR12) LOWZ ($\bar{z} = 0.32$ ) and the 803 112 LRGs of BOSS DR12 CMASS ($\bar{z} = 0.57$ ). In LOWZ, we find 3.1σ evidence for a non-zero parity-odd 4PCF, and in CMASS we detect a parity-odd 4PCF at 7.1σ. Gravitational evolution alone does not produce this effect; parity-breaking in LSS, if cosmological in origin, must stem from the epoch of inflation. We have explored many sources of systematic error and found none that can produce a spurious parity-odd signal sufficient to explain our result. Underestimation of the noise could also lead to a spurious detection. Our reported significances presume that the mock catalogues used to calculate the covariance sufficiently capture the covariance of the true data. We have performed numerous tests to explore this issue. The odd-parity 4PCF opens a new avenue for probing new forces during the epoch of inflation with 3D large-scale structure; such exploration is timely given large upcoming spectroscopic samples such as Dark Energy Spectroscopic Instrument and Euclid.

(Post‐)industrial optics: The role of the Hereford Mappa Mundi in Christopher Meredith'sShifts

AbstractChristopher Meredith's novelShifts(1988) is firmly established in the canon of English‐language Welsh literature as one of the most accomplished representatives of (post‐)industrial fiction, a genre this small country has produced in quality and amount ‘out of all proportion to its size or population’ (Knight, 2004). The aim of this paper is to explore the role of the medieval Mappa Mundi which two characters see in Hereford Cathedral in the context of the novel's circular structure and a rich network of other visual insets. Looking at the map from a variety of perspectives, including Murray Krieger's concept of ekphrasis as the superimposition of spatial relationships on a text by a visual work of art, I propose to read the fictional continuum of the novel as a mirror image of the medievalorbis terrarumon several planes: compositional, visual‐optical and symbolic. This reading is embedded within the broader context of the characteristics of the Welsh industrial novel discussed by Raymond Williams in his essay ‘The Welsh industrial novel’ (1979).

""On Being Sane in Insane Places" … it is a work half done."

""On Being Sane in Insane Places" … it is a work half done."

Daily Commuting and Parking Pattern under the Fully Station-Based One-Way Carsharing Vehicle Environment

This study is the first in the literature to investigate the joint equilibrium of departure time and parking location choices in the station-based one-way carsharing system. Time-varying road tolls are optimized to eliminate queueing deadweight loss, minimize schedule delay cost, and induce an economically efficient parking pattern. The round-trip commuting pattern under the fully privately owned vehicle environment was also studied, and the aggregate social cost of the two travel modes are compared with each other to verify the potential benefit gained from implementing the one-way carsharing service. We then investigated demand elasticity with respect to the user’s daily travel cost in a one-way carsharing-only system, and an externality-based charging mechanism is proposed to achieve the optimal demand-supply level. In the one-way carsharing-only travel mode, the following results were obtained: (1) the evening commute pattern is not a simple mirror image of the morning one when spatial parking is considered in both scenarios with and without pricing; (2) when taking account of elastic demand, in optimal time-varying pricing regimes, the charging scheme automatically leads to the socially optimal demand level, but in free-pricing regime, additional user anonymous tax must be charged to achieve the optimal demand level; and (3) the station-based one-way carsharing service benefits the public in aggregate social cost saving compared with the mode of driving a self-owned car.

Comparison study of mouse brain tissue by using ToF-SIMS within static limits and hybrid SIMS beyond static limits (dynamic mode).

In the study of degenerative brain diseases, changes in lipids, the main component of neurons, are particularly important because they are used as indicators of pathological changes. One method for the sensitive measurement of biomolecules, especially lipids, is time-of-flight secondary ion mass spectrometry (ToF-SIMS) using pulsed argon cluster ions. In this study, biomolecules including various lipids present in normal mouse brain tissue were measured using ToF-SIMS equipped with pulsed argon cluster primary ions. Based on the ToF-SIMS measurement results, hybrid SIMS (OrbiSIMS), which is a ToF-SIMS system with the addition of an orbitrap mass analyzer, was used to directly identify the biomolecules by the region in the real tissue samples. For this, the results of ToF-SIMS, which measured the tissue samples from a single mouse brain within static limits, were compared with those from OrbiSIMS measured beyond the static limits in terms of the differences in molecular profiling. From this analysis, two types of positive and negative ions were selected for identification, with the OrbiSIMS MS/MS results indicating that the positive ions were glycerophosphocholine and the negative ions were glycerophosphoinositol and sulfatide, a sphingolipid. Then, to confirm the identification of the molecular candidates, lipids were extracted from mirror image tissue samples, and LC-MS/MS also using an orbitrap mass analyzer was performed. As a result, the direct identification of molecular candidate groups distributed in particular regions of the tissue samples via OrbiSIMS was found to be consistent with the identification results by LC-MS/MS for extracted samples.

Ausländische Direktinvestitionen und lokale Wissensbasis: Die Einbettung von Niederlassungen in die deutsche duale Ausbildung

Dual vocational education and training systematically combines the learning of apprentices (in vocational schools) or students (in applied universities) with the ‘learning venue’ of the company. The dual vocational education and training exists in Germany, Austria and Switzerland and stands for regional competitiveness as well as for job opportunities of young people on the local labour market. Outside of these three countries, the dual system hardly exists, but dual practices are subject of international skill transfer policies. While this transfer is well researched, it is hardly known to what extent (in mirror image) subsidiaries of foreign companies take part in the dual system of German speaking countries. This question was examined, by focussing on subsidiaries of multinational companies in Germany. Theoretically, the contribution relates to research on local knowledge bases and the embeddedness of foreign subsidiaires. The study pursues a qualitative method. The results show that the local training managers have freedom for decision-making and use this in favour of getting involved in dual vocational education and training. However, the effort turns out to be high. Dual activities take place primarily as a strategy for adapting to the institutional environment, not as a way of shaping the environment. The local stakeholders are mostly reactive in this regard. This points to possible future fields of research on local knowledge bases and local embeddedness and, with regard to practice, to the relevance of mutual coordination.

Recognition of digital twin city from the perspective of complex system theory: Lessons from Chinese practice

Urban system theory seeks to comprehensively capture the complexity of cities. Digital twin cities are “digital mirror images” or symbionts of physical cities, and thus, they form a complex adaptive system. Unlike the reductionist practice of urban informatization and digitalization, digital twins are expected to enable human beings to enjoy the complex beauty of the city for the first time, capable to perceive more information of city and deal with more complex urban problems. Some practical misunderstandings have emerged, however, as a result of simple technical stacking, which is not able to solve urban problems from the root of the problem; has biased thinking about digital twin cities, which treats them as technical tools; and has slowed development of digital twin innovative applications. To solve these problems, we need to draw on basic urban theory. On the basis of complex system theory, in this study, we comprehensively analyzed the characteristics and mechanisms of digital twin cities and constructed a system framework for digital twin cities. We further elucidated the digital twin city and deconstructed it from the perspective of system theory into four subsystems: the planning system, infrastructure system, industrial system, and public service facility system. We then analyzed the subsystem rules and changes in the digital twin city, as well as the principles and development trends that conform to the self-organization and self-adaptive laws of the city.

Stroke syndrome Z: Bilateral Symmetrical Corona Radiata strokes causing facial diplegia, anarthria, and quadriparesis mimicking an acute neuromuscular syndrome (P3-5.025)

<h3>Objective:</h3> We report a 63-year-old man with consecutive, bilateral, and symmetrical Corona Radiata infarcts within 4 weeks duration, who presented with quadriparesis in addition to acute onset anarthria, and facio-labio-glosso-pharyngo-laryngeal paralysis. To our knowledge, there are no reported cases of recurrent lacunar stroke affecting the same area in the contralateral hemisphere as seen in our case. <h3>Background:</h3> Stroke is a leading cause of death and disability in the United states and particularly in our region; western New york. Around ¼ of annual strokes are recurrent strokes. It is important to identify clinical stroke syndromes to prevent any delays in care and possible clinical deterioration associated with that delay. <h3>Design/Methods:</h3> Case report <h3>Results:</h3> A 63 year-old-male with a recent history of left corona radiata stroke with residual right-sided weakness was evaluated by the neurology team for acute onset anarthria, tongue hypotonia, difficulty with chewing, swallowing and mastication along with quadriplegia. Patient was unable to open mouth on command but was able to yawn. Brain MRI revealed an acute right corona radiata infarct, a mirror image of the recent left corona radiata infarct. Gradually, upper motor neuron signs start to appear on day 2. <h3>Conclusions:</h3> Our patient suffered an acute left corona radiation infarct, almost perfectly symmetrical to a subacute right corona radiata infarct that occurred a month prior. Due to involvement of bilateral posterior limb of internal capsule, initial presentation was acute flaccid paralysis with quadriparesis and cranial neuropathy. Initial working diagnosis was acute neuromuscular disorder rather than stroke due to clincal presentation. Loss of bilateral symmetrical neural impulse can lead to atypical presentation in acute state. <b>Disclosure:</b> Dr. Shaikh has nothing to disclose. Dr. Ouf has nothing to disclose. Dr. Van Coevering has nothing to disclose. Dr. Kandel has nothing to disclose.

Combined Open-Slot and Monopole 8 × 8 High-Isolation Broadband MIMO Antenna System for Sub-6 GHz Terminals

In this article, an 8 × 8 MIMO antenna system with multidecoupling structures is proposed for the fifth-generation (5G) terminal applications. First, an antenna element consisting of an L-shaped open slot with dimensions of 5.6 × 5 mm2 and two bent-L-shaped monopoles with dimensions of 12.7 × 6.1 mm2 is introduced. Due to coupling feed technology, the initial open slot owns a wide bandwidth from 3.62 GHz to 4.82 GHz. For broadening the bandwidth of the initial antenna element, two bent-L-shaped monopoles are added to the open slot to adjust the input impedance. By optimizing the parameters of monopoles, the proposed antenna element has been finally determined and the bandwidth of the antenna element has been broadened (2.82 GHz to 5.23 GHz). Second, a dual antenna pair is constructed by placing the two antenna elements with an edge-to-edge distance of 27 mm in a mirror image placement; the 8 × 8 MIMO antenna system is brought about by symmetrically disposing four such antenna pairs with an edge-to-edge distance of 47 mm. Moreover, the isolation of two closely placed antenna elements is achieved by the parasitic strip-loading technique and defective ground techniques. Due to the decoupling techniques used in the 8 × 8 MIMO antenna system, the average isolation has been optimized from 13.2 dB to 21.9 dB and the total efficiency of each antenna element has been improved from a worst 20% to over 45%. Besides, the calculated mean efficiency gain is less than 1 dB, and the calculated envelop correlation coefficient (ECC) is lower than 0.01 for desired frequency bands. Furthermore, the proposed 8 × 8 MIMO antenna system has the measured broadband bandwidth from 3.28 GHz to 5.05 GHz (covering N77, N78, and N79 bands) and a compatible dimension for ultra-thin mobile phones. The simulated results of this work are all obtained from EM software CST STUDIO SUITE 2019. In general, the proposed 8 × 8 MIMO antenna system with a high-isolation property provides a hopeful solution to 5G ultra-thin mobile phones.