Substructural Elements Research Articles

Time-series reconstruction of the molecular architecture of human centriole assembly

Centriole biogenesis, as in most organelle assemblies, involves the sequential recruitment of sub-structural elements that will support its function. To uncover this process, we correlated the spatial location of 24 centriolar proteins with structural features using expansion microscopy. A time-series reconstruction of protein distributions throughout human procentriole assembly unveiled the molecular architecture of the centriole biogenesis steps. We found that the process initiates with the formation of a naked cartwheel devoid of microtubules. Next, the bloom phase progresses with microtubule blade assembly, concomitantly with radial separation and rapid cartwheel growth. In the subsequent elongation phase, the tubulin backbone grows linearly with the recruitment of the A-C linker, followed by proteins of the inner scaffold (IS). By following six structural modules, we modeled 4D assembly of the human centriole. Collectively, this work provides a framework to investigate the spatial and temporal assembly of large macromolecules.

DETERMINATION OF THE UPPER LIMIT OF THE LOAD-LOADING CAPACITY OF BENDING REINFORCED METAL-COMPOSITE RING PLATES IN CONTACT WITH A LIQUID INCOMPRESSIBLE MEDIUM 1. PROBLEM FORMULATION AND CALCULATION METHOD

The problem of determining the load-bearing capacity of a bendable reinforced annular plate resting on an incompressible liquid base is considered. The internal opening of the structure is closed with a continuous, absolutely rigid insert. The connection between the insert and the plate can be rigid or hinged. The structure is supported on the outer edge, and it is possible to move the support in the vertical direction, for example in the case of a movable jamming. In the limiting state, liquid flow from one front surface of the plate to another surface is not allowed. The materials of the components of the composition are isotropic and rigid-plastic, having the same yield limits in tension and compression. Plastic flow in the phases of the composition is associated with piecewise linear yield criteria (such as the Tresk's or Ishlinsky - Ivlev's yield conditions). The limit state of such a composite plate is described within the framework of the classical theory of transverse bending. Reinforcement structures have axial and radial symmetry. Two reinforcement options are considered: laying two families of fibers along radially symmetrical spiral trajectories and reinforcement in the radial and circumferential directions. The rein-forcing fibers are assumed to be continuous and have constant cross sections along their length, which gives rise to significant heterogeneity of the structures under consideration in the radial direction. The plastic flow of a metal-composition is calculated using a structural model that takes into account the presence of a plane stress state in all substructural elements. Structural formulas have been written that make it possible to determine the coordinates of corner points on piecewise linear yield curves of the compositions under consideration, taking into account their dependence on non-uniform reinforcement parameters: angles and densities. An extremal principle has been formulated that makes it possible to obtain an upper (kinematic) estimate of the maximum load for this type of structure. The formulated problem is discretized along the polar radius. Nodal values of the sagging speed and mechanical energy dissipation were used as unknown grid functions. A numerical algorithm for solving the formulated discretized problem has been developed, based on the application of the simplex method of linear programming theory.

The role of nickel in forming a structure providing increased service properties of reactor structural materials

Nickel is an essential alloying element in steels used as structural materials in the most common nuclear power reactors of the VVER type. The paper considers reviews the results of structural studies of traditional and advanced materials of the vessels and internals of VVER-type reactors with high nickel contents in their compositions. It is shown that an increased nickel content (up to 5 wt.%) in the steels of VVER pressure vessels contributes to the formation of a more dispersed structure with a smaller size of substructural elements and an increased density of dislocations, as well as a higher volume density of carbide phases. The revealed features of the structure of the reactor pressure vessel steel with high nickel content have the prerequisites for improving the strength and viscoplastic properties due to the increased number of barriers both for the dislocation motion and brittle crack propagation. Using the example of materials for VVER internals, it is shown that the nickel content increased in them up to 25 wt.% contributes to an increase in the volume density of radiation defects (dislocation loops of various types) and radiation-induced phase precipitates (G-phase). As nickel increases from 10 to 25 wt.%, there is a tendency to reduce swelling, which contributes to less shape change of the components of the reactor vessel internals. At the same time, in the steel with the highest nickel content, the highest nickel content was found in the near-boundary regions of the matrix, which contributes to greater austenite stability and a lower probability of the formation of an embrittling α-phase. The data obtained in the work on the effect of nickel alloying on the steel structural phase state and service characteristics were used in the development of new materials for the vessels and internals of advanced reactors.

Conformational Effects on the Passive Membrane Permeability of Synthetic Macrocycles.

Macrocyclic compounds (MCs) can have complex conformational properties that affect pharmacologically important behaviors such as membrane permeability. We measured the passive permeability of 3600 diverse nonpeptidic MCs and used machine learning to analyze the results. Incorporating selected properties based on the three-dimensional (3D) conformation gave models that predicted permeability with Q2 = 0.81. A biased spatial distribution of polar versus nonpolar regions was particularly important for good permeability, consistent with a mechanism in which the initial insertion of nonpolar portions of a MC helps facilitate the subsequent membrane entry of more polar parts. We also examined effects on permeability of 800 substructural elements by comparing matched molecular pairs. Some substitutions were invariably beneficial or invariably deleterious to permeability, while the influence of others was highly contextual. Overall, the work provides insights into how the permeability of MCs is influenced by their 3D conformational properties and suggests design hypotheses for achieving macrocycles with high membrane permeability.

СУЧАСНИЙ СТАН ТА ПЕРСПЕКТИВИ РОЗВИТКУ НАНОСТРУКТУРУВАННЯ ДЕФОРМОВАНИХ МЕТАЛІВ І СПЛАВІВ ТА НАПИЛЕНИХ ПОКРИТТІВ

The information presented in the article is an overview of the possibility of improving the mechanical properties of metals, alloys and sprayed coatings in order to obtain a dispersed, in particular, nanoscale substructure, which allows obtaining a set of unique operational characteristics, which, in turn, will increase the resource of parts of machines and mechanisms that are used in mechanical engineering.Today, the most common methodof nanostructuring is intensive plastic deformation (by friction, by equal-channel angular pressing, etc.), however, these methods can only be used for the manufacture of parts with a small cross-section, so the creation of new methods of deformation-thermal treatment is an urgent task of modern materials science.The paper shows the possibility of applying pre-deformation and pre-recrystallization heat treatment for technically pure iron, carbon steels of 1020 (сталь 20), 1045 (сталь 45), 1070 (сталь 70),A284Gr.D (Ст3) and C80W (У8) brands, alloyed steels of 5140H (40Х) and AISI 420 (20Х13) brands, Sv-08G2S (Св-08Г2С) gas-thermal and electric arc coatings, as well as Ni80Cr20 nichrome alloy and CuA19Mn2 (2.0960) bronze (БрАМц9-2).The work compares methods of static deformation with methods of intensive plastic deformation and shows that pre-recrystallization heat treatment allows to significantly strengthen metals (more than 30%) in combination with sufficient plasticity (for A284Gr.D (Ст3) steel, the relative elongation is up to 7.5%, and the relative narrowing is up to 75 %).The work presents the results of the experimental investigation of the influence of deformation and thermal factors on the mechanical properties, in particular, hardness and strength, of metals, alloys and sprayed coatings. It is established that the strengthening effect occurs due to the refinement of substructural elements, such as the size of coherent scatteringregions, the disorientation angle of subgrains, and the number of substructural elements to a nanoscale state. Thus, with the help of additional deformation followed by pre-recrystallization and heat treatment of carbon and alloyed steels, it is possible to obtain subgrains with a size of less than 200 nm with a disorientation angle of up to 2 ° with a relative amount of nanoscale subgrains of up to 65%.The possibility of industrial application of the proposed technology is shown on the example of production of regulating springs of membrane valves of pipelines made of 1070 (сталь 70) steel, which allows to increase the hardness by 19%.

Tri Concomitant Local Feature Learning for Diabetic Retinopathy Classification

In this paper, we have proposed a new technique entitled as Transformed Directional Tri Concomitant Triplet Patterns with Artificial Neural Network is proposed for Diabetic Retinopathy Classification. TdtCTp consist of three stages to obtain detail directional information about pixel progression. In first stage, structural rule based approach is proposed to extract directional information in various direction. Further, in second stage, microscopic information and correlation between each sub-structural element are extracted by using concomitant conditions. Finally, minute directional intensity variation information and correlation between the sub-structural elements are extracted by integrating first two stages. After feature extraction, the extracted feature is used as input to the artificial neural network. To the best of our knowledge, this is the first learning based approach for diabetic retinopathy classification. Effectiveness of the proposed method is evaluated in terms of average precision and compared with existing state-of-the-art methods. The experimental analysis shows that the proposed method is achieved significant performance compared to other methods.

Biosynthesis of Hyaluronic acid polymer: Dissecting the role of sub structural elements of hyaluronan synthase

Hyaluronic acid (HA) based biomaterials have several biomedical applications. HA biosynthesis is catalysed by hyaluronan synthase (HAS). The unavailability of 3-D structure of HAS and gaps in molecular understanding of HA biosynthesis process pose challenges in rational engineering of HAS to control HA molecular weight and titer. Using in-silico approaches integrated with mutation studies, we define a dictionary of sub-structural elements (SSE) of the Class I Streptococcal HAS (SeHAS) to guide rational engineering. Our study identifies 9 SSE in HAS and elucidates their role in substrate and polymer binding and polymer biosynthesis. Molecular modelling and docking assessment indicate a single binding site for two UDP-substrates implying conformationally-driven alternating substrate specificities for this class of enzymes. This is the first report hypothesizing the involvement of sites from SSE5 in polymer binding. Mutation at these sites influence HA production, indicating a tight coupling of polymer binding and synthase functions. Mutation studies show dispensable role of Lys-139 in substrate binding and a key role of Gln-248 and Thr-283 in HA biosynthesis. Based on the functional architecture in SeHAS, we propose a plausible three-step polymer extension model from its reducing end. Together, these results open new avenues for rational engineering of Class I HAS to study and regulate its functional properties and enhanced understanding of glycosyltransferases and processive enzymes.

Эволюция икосаэдрических частиц меди в процессе их роста при электрокристаллизации

Metal icosahedral microparticles with six fifth-order symmetry axes, a specific faceting and high catalytic activity, open up wide opportunities for their usage as catalysts capable of operating in fluidized bed reactors. In this paper, microparticles of copper of the icosahedral habitus about 15 microns in size in the form of truncated icosahedra have been grown for the first time by electrodeposition from sulfuric acid phate electrolyte. Such icosahedra are faceted by twelve {110} crystallographic planes and twenty {111} planes. Studies of the morphology of the surface of copper truncated icosahedra using metallography and electron microscopy have shown that in the process of growth they transform into perfect icosahedra faceted only by {111} planes. The structure of icosahedral copper particles has been studied in detail. Electron microscopic studies of the cross section of copper icosahedral particles show that they consist of sub-structural volume elements (fragments) that are separated from each other by twin and (or) dislocation boundaries. Often inside the fragments there are broken boundaries, near which extinction contours of dislocation origin are observed. In addition, coherent twin boundaries of the {111} <112> type are observed inside the fragments; they do not create long-range stress fields, twin layers, insertions and dislocations. Pentagonal pits appear on the surface of particles in the process of electrodeposition or etching, which indicate the presence of partial disclinations there. According to the results of experimental data, a scheme for the evolution of truncated icosahedra in the process of copper electrocrystallization into perfect icosahedra is proposed. Using the disclination approach, the density of the total free energy of a truncated and perfect icosahedron has been estimated and it is shown that the transformation of a truncated icosahedron into a perfect one is energetically justified.

Кристаллографические особенности структуры alpha-фазы гафния и сплавов гафний--титан

AbstractThe structure of a hafnium crystal undergoing β → α (bcc → hcp) polymorphic transformation upon gradual cooling and the structure of Hf_55Ti_45 and Hf_30Ti_70 alloys formed under various kinetic conditions of polymorphic transformation are studied. The structure of the α phase in cast hafnium is shown to consist of lath crystals grouped into packets. The misorientations between separate laths in a packet are less than 1°. The Hf–Ti alloys in the cast state exhibit a mixed structure consisting of α-phase crystals of several morphological types. A structure of packet martensite is observed in the Hf–Ti alloys after quenching. Each packet includes laths of several crystallographic orientations. There is no regular alternation of differently orientated laths in the packet. The same set of α-phase orientations within an initial β-phase grain is observed independently of the cooling rate of the Hf–Ti alloys upon β → α polymorphic transformation. The misorientation of substructural elements within an α-phase crystal in the Hf–Ti alloys is ~5° for the cast state and ~2.2° after quenching.

Crystallographic Features of the α-Phase Structure in Hafnium and Hafnium–Titanium Alloys

The structure of a hafnium crystal undergoing β → α (bcc → hcp) polymorphic transformation upon gradual cooling and the structure of Hf55Ti45 and Hf30Ti70 alloys formed under various kinetic conditions of polymorphic transformation are studied. The structure of the α phase in cast hafnium is shown to consist of lath crystals grouped into packets. The misorientations between separate laths in a packet are less than 1°. The Hf–Ti alloys in the cast state exhibit a mixed structure consisting of α-phase crystals of several morphological types. A structure of packet martensite is observed in the Hf–Ti alloys after quenching. Each packet includes laths of several crystallographic orientations. There is no regular alternation of differently orientated laths in the packet. The same set of α-phase orientations within an initial β-phase grain is observed independently of the cooling rate of the Hf–Ti alloys upon β → α polymorphic transformation. The misorientation of substructural elements within an α-phase crystal in the Hf–Ti alloys is ~5° for the cast state and ~2.2° after quenching.

Potent inhibitors of malarial P. Falciparum protein kinase G: Improving the cell activity of a series of imidazopyridines

Development of a class of bicyclic inhibitors of the Plasmodium falciparum cyclic GMP-dependent protein kinase (PfPKG), starting from known compounds with activity against a related parasite PKG orthologue, is reported. Examination of key sub-structural elements led to new compounds with good levels of inhibitory activity against the recombinant kinase and in vitro activity against the parasite. Key examples were shown to possess encouraging in vitro ADME properties, and computational analysis provided valuable insight into the origins of the observed activity profiles.

Dichlorophenyl piperazines, including a recently-approved atypical antipsychotic, are potent inhibitors of DHCR7, the last enzyme in cholesterol biosynthesis

While antipsychotic medications provide important relief from debilitating psychotic symptoms, they also have significant adverse side effects, which might have relevant impact on human health. Several research studies, including ours, have shown that commonly used antipsychotics such as haloperidol and aripiprazole affect cholesterol biosynthesis at the conversion of 7-dehydrocholesterol (7-DHC) to cholesterol. This transformation is promoted by the enzyme DHCR7 and its inhibition causes increases in plasma and tissue levels of 7-DHC. The inhibition of this enzymatic step by mutations in the Dhcr7 gene leads to Smith-Lemli-Opitz syndrome, a devastating human condition that can be replicated in rats by small molecule inhibitors of DHCR7. The fact that two compounds, brexpiprazole and cariprazine, that were recently approved by the FDA have substructural elements in common with the DHCR7 inhibitor aripiprazole, prompted us to evaluate the effect of brexpiprazole and cariprazine on cholesterol biosynthesis. We report that cariprazine affects levels of 7-DHC and cholesterol in cell culture incubations at concentrations as low as 5 nM. Furthermore, a common metabolite of cariprazine and aripiprazole, 2,3-(dichlorophenyl) piperazine, inhibits DHCR7 activity at concentrations comparable to those of the potent teratogen AY9944. The cell culture experiments were corroborated in mice in studies showing that treatment with cariprazine elevated 7-DHC in brain and serum. The consequences of sterol inhibition by antipsychotics in the developing nervous system and the safety of their use during pregnancy remains to be established.

Accounting for anisotropy of properties of substructural elements in study of strength of macroinhomogeneous media in the case of plane stressed state

In this paper on the mathematical model of a multiphase medium (with longitudinally transverse arrangement of phases) and the algorithm for calculating strength under combined thermomechanical loading the method is proposed for analyzing the limiting state of a composite, which allows one to take into account the internal structure of the material and the anisotropy of the elastic and thermal properties of substructural elements. For each element of the composition the strength condition of P. P. Balandin is used. It takes into account various limits of tensile strength and compression of phase materials. A numerical study of condition of initial destruction of composites and its various sections in space of parameters of the external action under isothermal loading in the case of plane stressed state is made.

New Frontiers on Seismic Modeling of Masonry Structures

An accurate evaluation of the nonlinear behaviour of masonry structural elements in existing buildings still represents a complex issue that rigorously requires nonlinear finite element strategies difficult to apply to real large structures. Nevertheless, for the static and seismic assessment of existing structures, involving the contribution of masonry materials, engineers need reliable and efficient numerical tools, whose complexity and computational demand should be suitable for practical purposes. For these reasons the formulation and the validation of simplified numerical strategies represents a very important issue in masonry computational research. In this paper an innovative macro-element approach, developed by the authors in the last decade, is presented. The proposed macro-element formulation is based on different, plane and spatial, macro-elements for the simulation of both the in-plane and out-of-plane behaviour of masonry structures also in presence of masonry elements with curved geometry. The mechanical response of the adopted macro-element is governed by nonlinear zero-thickness interfaces, whose calibration follows a straightforward fibre discretization, and the nonlinear internal shear deformability is ruled by equivalence with a corresponding geometrically consistent homogenized medium. The approach can be considered as ‘parsimonious’ since the kinematics of the adopted elements is controlled by very few degrees of freedom, if compared to a corresponding discretization performed by using nonlinear FEM strategies. This innovative discrete-element strategy has been implemented in two user-oriented software codes 3DMacro and HiStrA (Historical Structures Analysis), which simplifies the modelling of buildings and historical structures by means of several wizard generation tools and input/output facilities. The proposed approach, that represents a powerful tool for the structural assessment of structures in which the masonry plays a key role, is here validated against experimental results involving typical masonry monumental sub-structural elements and numerical results involving real-scale structures.

Diastereo- and enantioseparation of a Nα-Boc amino acid with a zwitterionic quinine-based stationary phase: Focus on the stereorecognition mechanism

A chiral chromatography method enabling the simultaneous diastereo- and enantioseparation of Nα-Boc-N4-(hydroorotyl)-4-aminophenylalanine [Boc-Aph(Hor)-OH, 1] was optimized with a quinine-based zwitterionic stationary phase. The polar-ionic eluent system consisting of ACN:MeOH:water—49.7:49.7:0.6 (v/v/v) with formic acid (4.0mM) and diethylamine (2.5mM), allowed the successful separation of the four acid stereoisomers: αd,d-/d,l-1=1.08; αd,l-/l,d-1=1.08; αl,d-/l,l-1=1.40.According to the in-house developed synthetic procedure and the recorded electronic circular dichroism spectra, the following stereoisomeric elution order was readily established in the optimal chromatographic conditions: d,d-1<d,l-1<l,d-1<l,l-1.With the aim of better understanding the molecular basis of the retention behaviour of the four stereoisomers in the employed chromatographic system and conditions, a computational protocol consisting in molecular dynamics simulations was applied. The use of the three descriptors INTER (in kcalmol−1, encoding for the interaction energy between the selector SO unit and the whole system), INTER_SA (in kcalmol−1, encoding for the interaction energy between SO and the sole selectand SA), and SELF (in kcalmol−1, encoding for the conformational energy of SA relative to its minimum energy registered by the collected snapshots) revealed the active role of achiral sub-structural elements of the chiral stationary phase and eluent components in the overall stereorecognition mechanism.

The Signature of the Five-Stranded vRRM Fold Defined by Functional, Structural and Computational Analysis of the hnRNP L Protein

The RNA recognition motif (RRM) is the far most abundant RNA binding domain. In addition to the typical β1α1β2β3α2β4 fold, various sub-structural elements have been described and reportedly contribute to the high functional versatility of RRMs. The heterogeneous nuclear ribonucleoprotein L (hnRNP L) is a highly abundant protein of 64kDa comprising four RRM domains. Involved in many aspects of RNA metabolism, hnRNP L specifically binds to RNAs containing CA repeats or CA-rich clusters. However, a comprehensive structural description of hnRNP L including its sub-structural elements is missing. Here, we present the structural characterization of the RRM domains of hnRNP L and demonstrate their function in repressing exon 4 of SLC2A2. By comparison of the sub-structural elements between the two highly similar paralog families of hnRNP L and PTB, we defined signatures underlying interacting C-terminal coils (ICCs), the RRM34 domain interaction and RRMs with a C-terminal fifth β-strand, a variation we denoted vRRMs. Furthermore, computational analysis revealed new putative ICC-containing RRM families and allowed us to propose an evolutionary scenario explaining the origins of the ICC and fifth β-strand sub-structural extensions. Our studies provide insights of domain requirements in alternative splicing mediated by hnRNP L and molecular descriptions for the sub-structural elements. In addition, the analysis presented may help to classify other abundant RRM extensions and to predict structure–function relationships.

Compressive and Flexural Behaviour of Unstressed Concrete Substructure in Cassava Effluent Contaminated Soils

Concrete research is gradually shifting from the conventional strength-based approach to durability-centred in the past decade. Durability is the measure of the robustness of constructed facilities against deterioration tendencies. The rate of deterioration is affected by the loading condition, and more importantly the physical and chemical nature of the host environments. This paper reports the experimental investigation of unstressed concrete substructure in the natural (uncontaminated) and cassava’s hydrocyanide effluent-polluted soils on the compressive and flexural strengths of buried concrete specimens for a maximum of 84 days. The compressive strengths of the cubes were tested every 7 days until the 84th day, while the beams were only subjected to third-point loading flexural tests at age 84 days. The compressive strength of concrete specimens in the two soil environments increased, though the trend was lower in the polluted soil. The strength reduced by 2.50% to 9.47% between the 7th and 28th days, but steadily between the 28th and 84th days with strength loss of 9.95% (COV = 2.64%). The load-deflection curves were quadratic for the beams in the two geo-environments. The beams in cyanide-polluted soil lost 34.5% of its flexural stiffness, while its loss of load-carrying capacities at the first crack and ultimate failure was 15.8% and 20% respectively. Higher degree of deterioration is certain for loaded concrete substructures in similar conditions. Hence, prior knowledge of soil chemistry is crucial to determining suitable concrete grade and nominal cover for durable substructural elements.

Internal transcribed spacer (ITS) evolution in populations of the hyperparasitic European mistletoe pathogen fungus, Sphaeropsis visci (Botryosphaeriaceae): The utility of ITS2 secondary structures

We investigated patterns of nucleotide polymorphism in the internal transcribed spacer (ITS) region for Sphaeropsis visci, a hyperparasitic fungus that causes the leaf spot disease of the hemiparasite European mistletoe (Viscum album). Samples of S. visci were obtained from Hungary covering all major infected forest areas. For obtaining PCR products we used a fast and efficient direct PCR approach based on a high fidelity DNA polymerase. A total of 140 ITS sequences were subjected to an array of complementary sequence analyses, which included analyses of secondary structure stability, nucleotide polymorphism patterns, GC content, and presence of conserved motifs. Analysed sequences exhibited features of functional rRNAs. Overall, polymorphism was observed within less conserved motifs, such as loops and bulges, or, alternatively, as non-canonical G–U pairs within conserved regions of double stranded helices. The secondary structure of ITS2 provides new opportunities for obtaining further valuable information, which could be used in phylogenetic analyses, or at population level as demonstrated in our study. This is due to additional information provided by secondary structures and their models. The combined score matrix was used with the methods implemented in the programme 4SALE. Besides the pseudoprotein coding method of 4SALE, the molecular morphometric character coding also has potential for gaining further information for phylogenetic analyses based on the geometric features of the sub-structural elements of the ITS2 RNA transcript.

The regularities of the formation of metal-glass materials and coatings with enhanced X-ray properties

This article discusses the use of new metal-glass materials and electric coatings for protection against X-ray radiation. The purpose of research is to establish regularities of formation of metal-glass materials and coatings, offering enhanced X-protective properties. Experimentally investigated the structure and X-ray protective properties: the mass attenuation coefficient of X-ray radiation and the specific lead equivalent to glass-aluminum composite materials and electric-arc coating of Sv-08G2S and Sv-AMg5 filled with hollow glass microspheres , powders of sodium silicate and the leaded glass . Established the attenuation effect of X-ray radiation by hollow glass microspheres, solid particles of liquid silicate the leaded glass, substructural elements formed as a result of heat treatment. Established regularities allow to manage the processes of formation of x-ray protective properties. The research results can be applied to the design of protection against the effects of X-ray emission for hardware, energy facilities, transportation, and medicine.

Operating point of Capacitive Micromachined Ultrasonic Transducers with Sub-structural Elements

CMUT FEM 2D electrostatic model was created to investigate dielectric surface roughness influence to the operating point. Three different form structures: triangle, half-circle, rectangle were investigated. The highest electric field norm concentration on the triangle apex was found. For experiments, dielectric surface was etched by two etching steps to define the cavity: reactive ion etching and buffered oxide etching for smoothing the cavity bottom. Atomic force microscopy was used to monitor and control the roughness of the cavity bottom. The simulation showed the decrease of the effective gap by 0.6 % and 1.0 % in 10 and 20 nm RMS cases, respectively. Voltage-capacitance tests of the fabricated devices with known roughness values confirmed the assumptions about the roughness-induced operating point shifts. DOI: http://dx.doi.org/10.5755/j01.eee.18.9.2804