Vectorial Orientation Research Articles

5D Opto‐Magnetization Endowed by Physics‐Enhanced Deep Learning

In the era of big data, all‐optical control of the magnetization is recognized as an alternative scheme that boosts the accelerating advance of multifunctional integrated opto‐magnetization devices with high‐density capacity. The light‐induced magnetizations demonstrated so far are devoted to steering their spatial orientations and structures by engineering the complicated phase, amplitude, and polarization modulations of incident wavefronts, which, however, confront low efficiency, weak flexibility, and limited dimension. To tackle these issues efficaciously, a novel strategy is proposed to first achieve 5D opto‐magnetization composed of 3D spatial location, vectorial orientation as well as magnitude. This relies on physics‐enhanced deep learning incorporating multilayer perceptron (MLP) artificial neural network and opto‐magnetization principles. The preeminent magnetization morphology largely expedites the improvement in multi‐dimensional storage. The proposed facile approach is time‐efficient, flexible, and accurate to attain the prescribed magnetization. Moreover, the presenting findings and proposed route are not only applied for magnetization manipulation, but also applicable to the control of the structured light field.

A crane-based five-axis manipulator for antenna tests

Antenna tests require precise positioning of an RF probe — at rest and during dynamic motions. Positioning includes the actual position of the tip of this probe and its vectorial orientation. This paper presents the automation and control concept for a novel crane-based measurement system. The system consists of a measurement gondola mounted to the hook of an overhead crane and designed such that it carries the probe and rotates it about two orthogonal axes. This system allows to arbitrarily position and orientate the probe in space on a given scanning surface. As the gondola is positioned using a crane, sway, skew, and tilting oscillations must be taken into account. Therefore a control concept is proposed that extends standard crane control by two additional degrees of freedom. For motion control with good trajectory tracking behavior, a flatness-based two-degree-of-freedom (2-DOF) state controller is applied for each axis. An extended Kalman filter is used for state estimation so that nonlinear effects and coupling between different axes are considered. The effectiveness of the proposed control concept is demonstrated by means of experimental results.

THE APPLICATION OF NON-STANDARD FORMS OF EMPLOYMENT AS MEANS OF STABILIZATION OF LABOUR MIGRATION IN UKRAINE

Urgency of the research. The rapid increase of migration flows from Ukraine threatens not only the loss of active labour potential, but also a significant decrease of the demographic potential of the country, which requires the introduction of effective measures to stabilize this process. Target setting. The solution to the problem of migration management lies in the area of improving social standards, quality of education, economic indicators, and especially the level of employment of the population. Actual scientific researches and issues analysis. Well - known scientists have made a significant contribution to the study of the Ukrainian migration, its causes, consequences, and possibilities of stabilization: A. Kruglashov, I. Gnybidenko, M. Romaniuk, E. Libanova, T. Lupul, O. Malynovska, V. Makar, A. Pozniak, U. Sadova, O. Sych, V. Troshchynskyi and others. Uninvestigated parts of general matters defining. At the same time, the use of flexible forms of employment as a factor of the stabilization of labour migration remains out of the question. The research objective. The analysis of the causes and the vectorial orientation of the flows of labour resource potential, which give rise to the need to use non-standard forms of employment as a prerequisite for the stabilization of labour migration. The statement of basic material. The article deals with the problem of labour migration in Ukraine. The factors of influence and vectorial orientation of emigration of the population of Ukraine are analyzed. The use of non-standard forms of employment as a means of stabilizing labour migratory flows is substantiated. The model of regulation of labour migration through the prism of application of non-standard forms of employment is offered. Conclusions. A number of social and economic factors pridetermines the migratory movement from Ukraine which leads to loss of the human and professional potential of the country. In this context, the use of non-standard forms of employment is one of the effective means of stabilizing migratory flows.

Full determination of single ferroelectric nanocrystal orientation by Pockels electro-optic microscopy.

We present a nanoscale electro-optic imaging method allowing access to the phase response, which is not amenable to classical second-harmonic generation microscopy. This approach is used to infer the vectorial orientation of single domain ferroelectric nanocrystals, based on polarization-resolved Pockels microscopy. The electro-optic phase response of KTP nanoparticles yields the full orientation in the laboratory frame of randomly dispersed single nanoparticles, together with their electric polarization dipole. The complete vector determination of the dipole orientation is a prerequisite to important applications including ferroelectric nanodomain orientation, membrane potential imaging, and rotational dynamics of single biomolecules.

Structural Characterization of the Voltage-Sensor Domain and Voltage-Gated K+-Channel Proteins Vectorially Oriented within a Single Bilayer Membrane at the Solid/Vapor and Solid/Liquid Interfaces via Neutron Interferometry

The voltage-sensor domain (VSD) is a modular four-helix bundle component that confers voltage sensitivity to voltage-gated cation channels in biological membranes. Despite extensive biophysical studies and the recent availability of X-ray crystal structures for a few voltage-gated potassium (Kv) channels and a voltage-gate sodium (Nav) channel, a complete understanding of the cooperative mechanism of electromechanical coupling, interconverting the closed-to-open states (i.e., nonconducting to cation conducting) remains undetermined. Moreover, the function of these domains is highly dependent on the physical-chemical properties of the surrounding lipid membrane environment. The basis for this work was provided by a recent structural study of the VSD from a prokaryotic Kv-channel vectorially oriented within a single phospholipid (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)) membrane investigated by X-ray interferometry at the solid/moist He (or solid/vapor) and solid/liquid interfaces, thus achieving partial to full hydration, respectively (Gupta et al. Phys. Rev. E2011, 84, 031911-1-15). Here, we utilize neutron interferometry to characterize this system in substantially greater structural detail at the submolecular level, due to its inherent advantages arising from solvent contrast variation coupled with the deuteration of selected submolecular membrane components, especially important for the membrane at the solid/liquid interface. We demonstrate the unique vectorial orientation of the VSD and the retention of its molecular conformation manifest in the asymmetric profile structure of the protein within the profile structure of this single bilayer membrane system. We definitively characterize the asymmetric phospholipid bilayer solvating the lateral surfaces of the VSD protein within the membrane. The profile structures of both the VSD protein and phospholipid bilayer depend upon the hydration state of the membrane. We also determine the distribution of water and exchangeable hydrogen throughout the profile structure of both the VSD itself and the VSD:POPC membrane. These two experimentally determined water and exchangeable hydrogen distribution profiles are in good agreement with molecular dynamics simulations of the VSD protein vectorially oriented within a fully hydrated POPC bilayer membrane, supporting the existence of the VSD's water pore. This approach was extended to the full-length Kv-channel (KvAP) at a solid/liquid interface, providing the separate profile structures of the KvAP protein and the POPC bilayer within the reconstituted KvAP:POPC membrane.

Acentric 2-D ensembles of D-br-A electron-transfer chromophores via vectorial orientation within amphiphilic n-helix bundle peptides for photovoltaic device applications.

We show that simply designed amphiphilic 4-helix bundle peptides can be utilized to vectorially orient a linearly extended donor-bridge-acceptor (D-br-A) electron transfer (ET) chromophore within its core. The bundle's interior is shown to provide a unique solvation environment for the D-br-A assembly not accessible in conventional solvents and thereby control the magnitudes of both light-induced ET and thermal charge recombination rate constants. The amphiphilicity of the bundle's exterior was employed to vectorially orient the peptide-chromophore complex at a liquid-gas interface, and its ends were tailored for subsequent covalent attachment to an inorganic surface, via a "directed assembly" approach. Structural data, combined with evaluation of the excited state dynamics exhibited by these peptide-chromophore complexes, demonstrate that densely packed, acentrically ordered 2-D monolayer ensembles of such complexes at high in-plane chromophore densities approaching 1/200 Å(2) offer unique potential as active layers in binary heterojunction photovoltaic devices.

Profile structures of the voltage-sensor domain and the voltage-gated K+-channel vectorially oriented in a single phospholipid bilayer membrane at the solid-vapor and solid-liquid interfaces determined by x-ray interferometry

One subunit of the prokaryotic voltage-gated potassium ion channel from Aeropyrum pernix (KvAP) is comprised of six transmembrane α helices, of which S1-S4 form the voltage-sensor domain (VSD) and S5 and S6 contribute to the pore domain (PD) of the functional homotetramer. However, the mechanism of electromechanical coupling interconverting the closed-to-open (i.e., nonconducting-to-K(+)-conducting) states remains undetermined. Here, we have vectorially oriented the detergent (OG)-solubilized VSD in single monolayers by two independent approaches, namely "directed-assembly" and "self-assembly," to achieve a high in-plane density. Both utilize Ni coordination chemistry to tether the protein to an alkylated inorganic surface via its C-terminal His_{6} tag. Subsequently, the detergent is replaced by phospholipid (POPC) via exchange, intended to reconstitute a phospholipid bilayer environment for the protein. X-ray interferometry, in which interference with a multilayer reference structure is used to both enhance and phase the specular x-ray reflectivity from the tethered single membrane, was used to determine directly the electron density profile structures of the VSD protein solvated by detergent versus phospholipid, and with either a moist He (moderate hydration) or bulk aqueous buffer (high hydration) environment to preserve a native structure conformation. Difference electron density profiles, with respect to the multilayer substrate itself, for the VSD-OG monolayer and VSD-POPC membranes at both the solid-vapor and solid-liquid interfaces, reveal the profile structures of the VSD protein dominating these profiles and further indicate a successful reconstitution of a lipid bilayer environment. The self-assembly approach was similarly extended to the intact full-length KvAP channel for comparison. The spatial extent and asymmetry in the profile structures of both proteins confirm their unidirectional vectorial orientation within the reconstituted membrane and indicate retention of the protein's folded three-dimensional tertiary structure upon completion of membrane bilayer reconstitution. Moreover, the resulting high in-plane density of vectorially oriented protein within a fully hydrated single phospholipid bilayer membrane at the solid-liquid interface will enable investigation of their conformational states as a function of the transmembrane electric potential.

Shear‐Induced Organization in Flexible Polymer Opals

Shear-induced organization in flexible polymer opals is studied using probing UV-surface diffraction combined with band gap measurements. These opals consist of a coherently ordered “super domain” characterized by a radial director vector and show anisotropic photonic behavior depending on the relative vectorial orientation of strain and director.

Combinatorial signaling by the Frizzled/PCP and Egfr pathways during planar cell polarity establishment in the Drosophila eye

Frizzled (Fz)/PCP signaling regulates planar, vectorial orientation of cells or groups of cells within whole tissues. Although Fz/PCP signaling has been analyzed in several contexts, little is known about nuclear events acting downstream of Fz/PCP signaling in the R3/R4 cell fate decision in the Drosophila eye or in other contexts. Here we demonstrate a specific requirement for Egfr-signaling and the transcription factors Fos (AP-1), Yan and Pnt in PCP dependent R3/R4 specification. Loss and gain-of-function assays suggest that the transcription factors integrate input from Fz/PCP and Egfr-signaling and that the ETS factors Pnt and Yan cooperate with Fos (and Jun) in the PCP-specific R3/R4 determination. Our data indicate that Fos (either downstream of Fz/PCP signaling or parallel to it) and Yan are required in R3 to specify its fate (Fos) or inhibit R4 fate (Yan) and that Egfr-signaling is required in R4 via Pnt for its fate specification. Taken together with previous work establishing a Notch-dependent Su(H) function in R4, we conclude that Fos, Yan, Pnt, and Su(H) integrate Egfr, Fz, and Notch signaling input in R3 or R4 to establish cell fate and ommatidial polarity.

Structural Studies of Amphiphilic 4-Helix Bundle Peptides Incorporating Designed Extended Chromophores for Nonlinear Optical Biomolecular Materials

Extended conjugated chromophores containing (porphinato)zinc components that exhibit large optical polarizabilities and hyperpolarizabiliites are incorporated into amphiphilic 4-helix bundle peptides via specific axial histidyl ligation of the metal. The bundle's designed amphiphilicity enables vectorial orientation of the chromophore/peptide complex in macroscopic monolayer ensembles. The 4-helix bundle structure is maintained upon incorporation of two different chromophores at stoichiometries of 1-2 per bundle. The axial ligation site appears to effectively control the position of the chromophore along the length of the bundle.

Incorporation of Designed Extended Chromophores into Amphiphilic 4-Helix Bundle Peptides for Nonlinear Optical Biomolecular Materials

Multipigment ensembles that feature (porphinato)metal components and appropriate ethyne- and oligoyne-based chromophore-to-chromophore connectivity can manifest large optical polarizabilities and hyperpolarizabilities by design. Their vectorial orientation and local environment are controlled upon incorporation into designed amphiphilic 4-helix bundle peptides via axial histidyl ligation without disturbing the peptide's helical secondary structure. The chromophore/peptide stoichiometry can be tuned by varying the peptide's oligomeric state. The chromophore/peptide complexes are thermally stable, making them ideal candidates for the fabrication of nonlinear optical biomolecular materials.

Comparative Structural Studies of Vpu Peptides in Phospholipid Monolayers by X-Ray Scattering

Vpu is an 81-residue HIV-1 accessory protein, its transmembrane and cytoplasmic domains each responsible for one of its two functions. Langmuir monolayers of phospholipid incorporating a membrane protein with a unidirectional vectorial orientation, on a semiinfinite aqueous subphase, provide one “membranelike” environment for the protein. The cytoplasmic domain's interaction with the surface of the phospholipid monolayer in determining the tertiary structure of the peptide within the monolayer was investigated, employing a comparative structural study of Vpu with its submolecular fragments Tm and TmCy truncated to different extents in the cytoplasmic domain, via synchrotron x-ray scattering utilizing a new method of analysis. Localizations of the transmembrane and cytoplasmic domains within the monolayer profile structure were similar for all three proteins, the hydrophobic transmembrane helix within the hydrocarbon chain region tilted with respect to the monolayer plane and the helices of the cytoplasmic domains lying on the surface of the headgroups parallel to the monolayer plane. The thickness of the hydrocarbon chain region, determined by the tilt of the hydrocarbon chains and transmembrane domain with respect to the monolayer plane, was slightly different for Tm, TmCy, and Vpu systematically with protein/lipid mole ratio. Localization of the helices in the cytoplasmic domains of the three proteins relative to the headgroups depends on their extents and amphipathicities. Thus, the interaction of the cytoplasmic domain of Vpu on the surface may affect the tilt of the transmembrane helix within the hydrocarbon chain region in determining its tertiary structure in the membrane.

Orientational Distributions of the Di-α-helical Synthetic Peptide ZnPPIX-BBC16 in Langmuir Monolayers by X-ray Reflectivity and Polarized Epifluorescence

The vectorial orientation of the peptide ZnPPIX-BBC16 in a Langmuir monolayer was studied by means of X-ray reflectivity and polarized epifluorescence. ZnPPIX-BBC16 consists of two α-helical 31-mers dimerized via a disulfide bridge between two N-terminal cysteines (α-S−S-α), so that two bis-his metalloporphyrin binding sites between positions 10,10‘ and 24,24‘ are formed. Zn(II) protoporphyrin IX was bound to the position 24. To enhance stability at the interface, a palmitoyl (C16) chain was bonded to each N-terminal cysteine. X-ray reflectivity measurements make it possible to infer the orientation of the α-helices by determining the electron density profile of the monolayer. Polarized epifluorescence provides the orientation distribution of the porphyrin with respect to the monolayer plane. Both X-ray and fluorescence measurements show that at low surface pressure (π = 5 mN/m), the peptide α-helices lie in the plane of the water surface with a narrow orientational distribution of the porphyrin. At high pressures (π > 30 mN/m), the peptide α-helices are perpendicular to the water surface and the distribution is wider. At intermediate pressures the peptide α-helices in the monolayer undergo a transition from the parallel to perpendicular orientation with almost a complete loss of the orientational order of the porphyrin.

Different contributions of pannier and wingless to the patterning of the dorsal mesothorax of Drosophila.

In Drosophila, the GATA family transcription factor Pannier and the Wnt secreted protein Wingless are known to be important for the patterning of the notum, a part of the dorsal mesothorax of the fly. Thus, both proteins are necessary for the development of the dorsocentral mechanosensory bristles, although their roles in this process have not been clarified. Here, we show that Pannier directly activates the proneural genes achaete and scute by binding to the enhancer responsible for the expression of these genes in the dorsocentral proneural cluster. Moreover, the boundary of the expression domain of Pannier appears to delimit the proneural cluster laterally, while antagonism of Pannier function by the Zn-finger protein U-shaped sets its limit dorsally. So, Pannier and U-shaped provide positional information for the patterning of the dorsocentral cluster. In contrast and contrary to previous suggestions, Wingless does not play a similar role, since the levels and vectorial orientation of its concentration gradient in the dorsocentral area can be greatly modified without affecting the position of the dorsocentral cluster. Thus, Wingless has only a permissive role on dorsocentral achaete-scute expression. We also provide evidence indicating that Pannier and U-shaped are main effectors of the regulation of wingless expression in the presumptive notum.

Vectorially Oriented Fixation of Membrane-Embedded Bacteriorhodopsin onto an Inert Base

This paper describes a novel surface processing technique aimed at the chemical fixation of proteins on substrate surfaces. The essential feature of this newly developed technique is a combination of chemical and enzymatic processes. A simple technique using chemical modification and selective enzymatic digestion for immobilizing biomembrane-embedded proteins on inorganic solid bases, while strictly regulating their vectorial orientation, was developed. These processes are applicable to a wide range of membrane-embedded and individual proteins, because they exploit the most fundamental principle of proteins, that any protein has at least one N-terminus and one C-terminus. After thorough protection of the carboxyl and amino groups on the molecular surface of bacteriorhodopsin (bR) embedded in purple membrane (PM), in which the bR molecules are uniformly oriented, the derivatized bR was subjected to successive enzymatic digestions to regenerate the unique N-terminal amino group on the molecular surface. The...

Vectorially-Oriented Monolayers of Cytochrome Oxidase: Fabrication and Profile Structures

Vectorially-oriented monolayers of detergent-solubilized bovine heart cytochrome c oxidase have been formed by self-assembly from solution and Langmuir−Blodgett (LB) deposition. Both quartz and Ge/Si multilayer substrates, the latter fabricated by molecular beam epitaxy, were alkylated with an amine-terminated alkylsiloxane monolayer prior to introduction to the protein. For the self-assembled protein monolayers, the amine end group surface provided for primarily electrostatic interactions with the protein, thereby encouraging a nearly unidirectional vectorial orientation of the so-adsorbed integral membrane protein. This was demonstrated by the analysis of meridional X-ray diffraction data from the monolayers so-adsorbed onto the Ge/Si multilayer substrates, which directly provided electron density profiles of the protein along the axis normal to the substrate plane to a spatial resolution of 10 Å. These profiles are consistent with the three-dimensional structure of the protein, obtained from electron microscopy. Patterson function analysis of meridional X-ray diffraction from the LB-deposited monolayers has shown the profile structure of the so-deposited protein monolayers to be qualitatively similar to that obtained via self-assembly from solution, thereby suggesting that the LB-deposited monolayers are similarly vectorially-oriented. Optical spectroscopy using quartz substrates has also indicated that the LB monolayers tend to be more densely packed than their self-assembled counterparts. Optical linear dichroism has confirmed that the planes of the oxidase's two heme groups and, hence, the molecule's long axis are more perpendicular to the monolayer plane in the LB case than for the self-assembled monolayers, consistent with the profile length of the molecule along the axis normal to the monolayer plane. Such densely packed, vectorially-oriented monolayers in a fully hydrated state now provide a unique opportunity to perform directly correlated structural−functional studies on this membrane protein.

Differential expression of perforin in muscle-infiltrating T cells in polymyositis and dermatomyositis.

Polymyositis (PM) and dermatomyositis (DM) are the prototypical inflammatory diseases of skeletal muscle. In PM, CD8+ T cells invade and destroy muscle fibers, whereas humoral effector mechanisms prevail in DM. We studied the expression of the cytotoxic mediator perforin in inflammatory cells in PM and DM muscle by semiquantitative PCR, immunohistochemistry and confocal laser microscopy. Similar levels of perforin mRNA were expressed in PM and DM, and abundant perforin-expressing CD3+CD8+ and CD3+ CD4+ T cells were observed in both diseases. However, there was a striking difference in the intracellular localization of perforin. In DM, perforin was distributed randomly in the cytoplasm of the inflammatory T cells. In contrast, 43% of the CD8+ T cells that contacted a muscle fiber in PM showed perforin located vectorially towards the target muscle fiber. The results suggest (a) that the random distribution of perforin in the cytoplasm of muscle-infiltrating T cells observed in DM reflects nonspecific activation, and (b) that the vectorial orientation observed only in PM reflects the specific recognition via the T cell receptor of an antigen on the muscle fiber surface, pointing to a perforin- and secretion-dependent mechanism of muscle fiber injury.

Vectorially oriented monolayers of detergent-solubilized Ca(2+) -ATPase from sarcoplasmic reticulum

A method for tethering proteins to solid surfaces has been utilized to form vectorially oriented monolayers of the detergent-solubilized integral membrane protein Ca(2+) -ATPase from the sarcoplasmic reticulum (SR). Bifunctional, organic self-assembled monolayers (SAMs) possessing "headgroup" binding specificity for the substrate and "endgroup" binding specificity for the enzyme were utilized to tether the enzyme to the substrate. Specifically, an amine-terminated 11-siloxyundecaneamine SAM was found to bind the Ca(2+)-ATPase primarily electrostatically. The Ca(2+)-ATPase was labeled with the fluorescent probe 5-(2-[(iodoacetyl)amino]ethyl)aminonaphthalene-1-sulfonic acid before monolayer formation. Consequently, fluorescence measurements performed on amine-terminated SAM/enzyme monolayers formed on quartz substrates served to establish the nature of protein binding. Formation of the monolayers on inorganic multilayer substrates fabricated by molecular beam epitaxy made it possible to use x-ray interferometry to determine the profile structure for the system, which was proved correct by x-ray holography. The profile structures established the vectorial orientation of the Ca(2+)-ATPase within these monolayers, to a spatial resolution of approximately 12 A. Such vectorially oriented monolayers of detergent-solubilized Ca(2+)-ATPase from SR make possible a wide variety of correlative structure/function studies, which would serve to elucidate the mechanism of Ca(2+) transport by this enzyme.

Homing Behaviour in Polyergus rufescens Latr. (Hymenoptera, Formicidae)

AbstractHoming mechanisms of the European slave‐making ant Polyergus rufescens Latr. are investigated by field experiments. The analysis of the behaviour and paths of both homing scouts and raiders after passive displacement showed that: i. Scouts probably home by using a path integration system based on celestial cues; and ii. Displaced raiders do not seem to adopt such a vectorial orientation mechanism. Moreover, we found that passively displaced scouts exhibit a systematic search strategy for the nest after a rectilinear path. By contrast, raiders perform a similar search pattern just after release. Similarities between Cataglyphis and Polyergus homing behaviour are discussed.

Determination of leukotriene effects on human neutrophil chemotaxis in vitro by differential assessment of cell motility and polarity

The effects of leukotriene (LT) B4 and D4 on the motility of human peripheral blood neutrophils were investigated employing a novel analytical method. Using the under-agarose technique, migration distance and vectorial orientation of neutrophils in response to selected LT concentrations were determined with the aid of digital image processing. Neutrophil polarization induced by a chemotactic gradient was very apparent even at fields taken adjacent to the cell seeding well where little directional cell motility had occurred. Thus, cell polarization appeared to be the earliest response to chemoattractive LTs. Cell motility occurred in a dose-dependent manner to LTB4 according to determination of the leading edge. LTD4 produced similar effects on neutrophil polarization and motility, but these occurred only at very high concentrations. These data support the view that vectorial orientation is a prerequisite for directional migration of cells and it is also feasible that these are separately regulated events. Furthermore, our studies confirm that LTB4 and, to a much lesser extent, LTD4 are chemotactic for human peripheral blood neutrophils.