Conformational Angles Research Articles

3D printed hernia mesh implant: a conformability study

Aim: This study aims to explore the sensing capabilities of polyvinylidene fluoride-hydroxyapatite-chitosan (PVDF-HAP-CS) composite-based hernia mesh implants (of conformal/planar design), followed by in-vitro analysis for better understanding of the bio-stability in the patient’s body. Methods: For analyzing the sensing capabilities, a microstrip patch antenna (MPA)-based implantable sensor [with 17-4 precipitate hardened (PH) stainless steel (SS) (bio-compatible) and Cu alloy (non-biocompatible) materials as conducting plane/patch with PVDF-HAP-CS as dielectric material] has been considered separately in this study. Primarily, in this study, the 3D models of the hernia mesh implant have been designed in the high-frequency structure simulator (HFSS) software, and the sensing behaviour of the same has been recorded. Results: The HFSS results represent that for the 17-4PH SS-based sensor, resonant frequency (fr) decreases from 2.3953 to 2.3800 GHz, whereas the gain increases from 0.54 to 4.02 dB with a SAR value of 1.077 W/kg. The fr for Cu alloy increases up to 30° conformal angle and, after that, starts decreasing, whereas the gain reaches 3.24 dB with a SAR value of 1.238 W/kg. The in-vitro study highlights that both materials (17-4PH SS and Cu alloy) possess a low corrosion rate. Conclusions: The simulation-based comparison of the biosensors with conducting elements 17-4PH SS and Cu alloy for different conformal angles indicates that the 17-4PH SS shows promising results over Cu in terms of higher gain (up to 4.02 dB) and low SAR value (1.077 W/kg) with the fr lying in the industry scientific and medical (ISM) band and therefore may be used for implantable sensor applications and possesses the capability to be used as 3D-printed hernia mesh implant. The in-vitro results with the low corrosion rate ≈ of 5.1 × 10–8 mm/year, 17-4PH SS may be a suitable material for the fabrication of hernia mesh implant.

The refinement of the parameters of β-turns using neutron diffraction data

Beta-bends are a difficult to interpret type of polypeptide chain backbone structure of globular proteins. Beta-bends are usually classified according to the dihedral angles φ and ψ of amino acid residues i + 1 and i + 2. Ramachandran map analysis of amino acid residues i + 1 and i + 2 indicates the resulting conformational stresses in bending. The mechanism of stabilization of their energetically disadvantageous conformations is still unclear. This kind of conformation stresses can only be compensated by additional interactions, such as additional hydrogen bonds, whose geometry and energy compensates for the beta-bending stress. Neutronography is the only available direct method for determining the position of hydrogen atoms in the structures of chemical compounds, including proteins. In this work, beta-bends from 176 protein structures from PDB established by neutronography are studied. In these structures, 3733 beta-bends were found using the i → i + 3 hydrogen bonding criterion. Using clustering by the magnitude of conformational angles, eight types of bends were newly identified. The magnitudes of conformational angles for each type of bend were determined. The hypothesis of additional hydrogen bonding to stabilize the bend was not confirmed, suggesting that the bending stress is compensated by other factors.

Exploring the impact of electron acceptor tuning in D-π-A′-π-A photosensitizers on the photovoltaic performance of acridine-based DSSCs: A DFT/TDDFT perspective

Nine novel organic molecules with D-π-A′-π-A motifs, designated as (Ac-T-Qs-T-CA) and (Ac-T-Bx-T-CA), were proposed as potential photosensitizers for use in dye-sensitized solar cells (DSSCs). These novel organic photosensitizers are comprised of an acridine electron donor (Ac) and a thiophene π-spacer (T), while the electron acceptor unit (A′) is either a substituted quinoxaline (Qs) or a benzo[2,5]diazole-1-heteroatom (Bx), and the anchoring group (A) is 2-cyanoacrylic acid (CA). The influence of electron acceptor (A′) moieties on the electronic, photophysical, thermodynamic and photovoltaic properties of the photosensitizers was analyzed using DFT and TD-DFT calculations. The MM3 force field and CONFLEX conformational search methods were employed to study all possible structural conformations of the photosensitizers. The goal was to identify the lowest energy conformer and gain a better understanding of how the structure conformation and torsional angles of (Ac-T-Qs-T-CA) and (Ac-T-Bx-T-CA) compared to the reference photosensitizer RK1 affect electron injection ability and overall performance of DSSCs. The thermodynamic analysis revealed that the photosensitizers (Ac-T-Q2,3-diOMe-T-CA) and (Ac-T-BtA-T-CA), which contain a 2,3-dimethoxyquinoxaline (Q2,3-diOMe) and a benzo[d][1,2,3]triazole (BtA) acceptor moieties, respectively, exhibit a noteworthy enhancement in their electron-injection free energy (ΔGinj) and a reduction in their recombination-free energy (ΔGrec) values, leading to an improvement in the overall photovoltaic properties of the solar cell when compared to the other photosensitizers. The photovoltaic characteristics of the photosensitizers showed that the photosensitizer (Ac-T-Q2,3-diOMe-T-CA) demonstrated the highest values of open-circuit photovoltage (Voc = 1.41 eV) and light harvesting efficiency (LHE = 0.80 eV) compared to the other (Ac-T-Qs-T-CA) photosensitizers. Similarly, (Ac-T-BtA-T-CA) photosensitizer demonstrated the highest Voc (1.08 eV) and LHE (0.75 eV) among (Ac-T-Bx-T-CA) photosensitizers. The photovoltaic performance of these new photosensitizers outperformed the reference RK1 photosensitizer, which only achieved a Voc of 1.2 eV and LHE of 0.61 eV. Finally, the electronic structures and optical properties of photosensitizers adsorbed on the TiO2 surface were studied to provide more accurate information about their adsorption on the semiconductor surface.

Interfacial films of cyclic polyguanamine derivatives for metal capturing: Selectivity and fluorescence emission properties

We demonstrated that the interfacial films of a cyclic moiety-containing polyguanamine derivative have selectivity for metal capturing. In addition, the selectivity of the fluorescence emission depending on the captured metal ion species was determined. The metal capturing of the polyguanamine Langmuir monolayer demonstrated high selectivity for the metal cations present in the subphase depending on the ionic radius and valence. Therefore, it was confirmed that metal cations with a small ionic radius and large valence tended to be preferentially captured. This is consistent with typical metal desorption behavior, and cations that are more difficult to desorb are preferentially captured. In addition, the tilt angle of the cup-shaped conformation at the annular site correlated with the metal capturing selectivity. Furthermore, the emission and quenching of the fluorescence changed significantly depending on the captured metal ion species.

Conformal Miniaturized Angular Stable Triband Frequency Selective Surface for EMI Shielding

This article presents single-layer conformal high angle stable miniaturized triband bandstop frequency selective surface (FSS) for microwave shielding. This new FSS is supported on an ultrathin dielectric substrate and has stable response with change in polarization and incidence angle. Via-less convoluted geometry is adopted in the unit cell design to increase spatial efficiency with a unit cell size of 0.091 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ_L</i> , where <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ_L</i> is the wavelength at lowest resonance. The proposed FSS exhibits three transmission zeros at 4, 6.95, 11.3 GHz with stopband bandwidth (BW) founds application for shielding the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</i> / <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</i> band frequencies for satellite communication. A prototype of the proposed FSS is fabricated. The filter response is measured on normal and on curved surfaces. Simulated and measured transmission coefficients confirm the operating principle of the FSS. Unit cell periodicity of the triband FSS is further reduced by using two layers based 2.5-D geometry. The modified unit cell has a periodicity of 0.038 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ_L</i> and exhibits stopband BWs center at 0.8, 1.4, and 2.36 GHz.

Flexible frequency-selective rasorber based on metal-graphene hybrid metamaterial.

In this work, we demonstrate a flexible frequency-selective rasorber (FSR) with great angular stability and conformal superiority using metal-graphene hybrid metamaterial. The metamaterial is fabricated by filling the designed metal patterns with graphene-based ink. It can replace the traditional resistors to introduce loss for the absorption purpose. Therefore, the FSR does not need any lumped components soldered onto its surface, enabling a high flexibility and conformal capability. The metal-graphene FSR is fabricated and measured on flexible substrates that have a 60° angular stability and a 128° conformal angle. The simulations and experiments confirmed that the proposed metal-graphene FSR exhibits excellent angular stability and considerable flexibility, making it ideal for stealth systems.

Measurement accuracy of foot conformation parameters on low-field magnetic resonance images in horses

Foot imbalance and malalignment of the digits are common in horses. Angle and distance measurements performed on bones, joints and hoof wall on radiographs provide essential guidance for precise corrective trimming and shoeing. This study aimed to investigate, if selected standing low-field magnetic resonance (MR) images can be used to accurately measure dorsopalmar and lateromedial foot conformation parameters in comparison to the radiographic gold standard. Images of 100 horses referred for standing low-field MR examination were selected. Foot conformation angles and distances were measured and compared between radiographs and MR images. Measurements from most imaging sources were significantly different from each other. Moderate to high correlation of foot conformation angles between radiographs and MR images in the lateromedial and dorsopalmar planes was found, with exception of the proximal interphalangeal joint angle, where there was only moderate agreement between radiographs and the 5-plane MR pilot (0.47, P < .001) and between radiographs and the 3-plane MR pilot (0.4, P < .001), respectively. Measurement of foot conformation parameters from low-field MR images should be used with caution in clinical practice and acquisition of current foot radiographs immediately before or after MR examination should be considered to facilitate precise trimming and shoeing.

O‧‧‧C═O interaction, its occurrence and implications for protein structure and folding.

Various noncovalent interactions, long and short range, stabilize the native protein structure. We had observed a short-range interaction between two adjacent peptide groups in a nearly perpendicular orientation through the involvement of an NH‧‧‧N hydrogen bond. Here we show that the other half of the peptide group, namely the carbonyl moiety, can also be involved through the O‧‧‧C═O interaction. Considering the interacting residues, the second residue of the pair has distinct backbone conformational angles, occurring in four clusters, each engendering well-defined structural motifs. One of the motifs is the γ-turn, another being polyproline II helix. The interacting pair is found mostly in the irregular region in protein structures, and the propensities of residues and the identification of the nearest secondary structure show interesting patterns. The most conspicuous β-turn conformation is built from two consecutive γ-turns, with embedded O‧‧‧C═O and NH‧‧‧N interactions, and there is considerable match of the residue usage at the central positions of the β-turn and the γ-turn components. This clearly exemplifies the hierarchical growth of the protein secondary structures, which would be important in our understanding of protein folding. While the occurrence of the O‧‧‧C═O interaction in α-helices has been well documented, we find it to be equally important in making capping interactions at helix termini.

Three-electron dynamics of the interparticle Coulombic decay with two-dimensional continuum confinement

In a pair of self-assembled or gated laterally arranged quantum dots, an electronically excited state can undergo interparticle Coulombic decay. Then, an electron from a neighbor quantum dot is emitted into the electronic continuum along the two available dimensions. This study proves that the process is not only operative among two but also among three quantum dots, where a second electron-emitting dot causes a rate increase by a factor of two according to the predictions from the analytical Wigner-Weisskopf rate equation. The predictions hold over the complete range of conformation angles among the quantum dots and over a large range of distances. Electron dynamics was calculated by multiconfiguration time-dependent Hartree and is, irrespective of the large number of discrete variable representation grid points, feasible after having developed an OpenACC graphic card compilation of the program.

213 Distribution of subjectively evaluated conformation traits in commercial growing replacement gilts

Abstract Feet and leg/locomotor issues represent a primary reason for sow removal from U.S. breeding herds. A shift from gestation stalls (GS) to group-sow housing (GSH) is occurring the U.S. swine industry, emphasizing the importance of structural soundness in replacement gilts. The objectives of this study were 1) to determine if feet and leg/body conformation score differences exist when evaluated at approximately 50 kgs. and 100 kgs.; 2) estimate subjectively scored feet and leg/body conformation trait repeatability within and across measurement time and scorer(s); and 3) determine if the ideal feet and leg conformation traits and scores within traits are the same within GS and GSH. A total of 4494 gilts were evaluated at approximately 22 weeks of age at 3 different farms within the same production system by 4 scorers, representing varying levels of experience. The conformation traits evaluated included locomotion score (LS), front and rear leg conformation (FLC and RLC), front and rear pastern angle (FP and RP), front and rear foot position (FFP and RFP), rib shape (RS), foot size (FS) and toe size (TS). Across farms, the mean gilt BW was 83 ± 11.5 kg. Across scorers and the entire gilt population, the mean conformation scores were: LS (0.06 ± 0.16), FLC (6.1 ± 0.54), RLC (5.4 ± 0.40), FP (3.6 ± 0.62), RP (4.0 ± 0.64), FFP (4.4 ± 0.31), RFP (4.1 ± 0.30), RS (4.3 ± 0.72), FS (2.0 ± 0.35) and TS (4.8 ± 0.61). The entire gilt population was divided amongst four individual sow herds (2 GS and 2 GSH). Sow performance will be followed for three parities to determine the relationship between production and longevity within gestation housing systems and determine if the relationships are associated with one or more conformation traits and/or differences in scores within each conformation trait.

Fungicidal Effect of Pyraclostrobin against Botrytis cinerea in Relation to Its Crystal Structure.

Pyraclostrobin (PYR) is a commonly used strobilurin fungicide, which inhibits mitochondrial respiration at the ubiquinol oxidation center site of the cytochrome bc1 complex. Little information is available regarding the crystal structure of PYR on its fungicidal effect. In this study, the crystal structures of eight PYRs (PYR-A to H) from different sources are determined by using high-resolution X-ray powder diffraction (XRPD) and model construction with the Pawley refinement module. The effects of PYRs on mycelium growth, the kinetics of mycelial growth, conidial germination, and tube elongation of conidia of Botrytis cinerea from tomato are compared. The level of organic acids in the mitochondrial tricarboxylic acid cycle of PYR-treated B. cinerea is analyzed. The results show that PYR-A to PYR-H have their own unique character of XRPD patterns, but the crystal morphology of eight PYRs presents in the triclinic crystal system and space group P1̅. PYR-D with the eclipsed conformation and rational edge angles α (72.599°) and β (98.612°) in the crystal cell shows the highest inhibitory effect against mycelium growth with EC50 as 3.383 μg mL-1, the best time-dependent effects on the mycelium growth kinetics, and the strongest inhibition on tube elongation of conidia, whereas PYR-E with anticonformation is the worst. Moreover, a significant accumulation of fumarate, malate, and oxalate in the PYR-D-treated mycelium is observed. These findings reinforce the need for a definite crystal structure of PYR to limit usage and mitigate future selection pressure for gray mold management.

Upper and Lower Bounds and Modulus of Continuity of Decomposed Möbius Energies

The Mobius energy is one of the knot energies, and is named after its Mobius invariant property. It is known to have several different expressions. One is in terms of the cosine of conformal angle, and is called the cosine formula. Another is the decomposition into Mobius invariant parts, called the decomposed Mobius energies. Hence the cosine formula is the sum of the decomposed energies. This raises a question. Can each of the decomposed energies be estimated by the cosine formula? Here we give an affirmative answer: the upper and lower bounds, and modulus of continuity of decomposed parts can be evaluated in terms of the cosine formula. In addition, we provide estimates of the difference in decomposed energies between the two curves in terms of Mobius invariant quantities.

A novel DNA based bioassay toward ultrasensitive detection of Brucella using gold nanoparticles supported histidine: A new platform for the assay of bacteria in the cultured and human biofluids with and without polymerase chain reactions (PCR)

Brucella organisms, which are small aerobic intracellular coccobacilli, localize in the reproductive organs of host animals, causing abortions and sterility. In this work, we used a novel method to preparation of excellent genosensor on the surface of low-toxic substrate (gold nanoparticles) supported histidine prepared by fully electrodeposition method. The results of the present work show that the nano-Au-Hist provide suitable active sites for the DNA probe immobilization. The fabricated DNA genosensor employs cyclic voltammetry (CV), and square wave voltammetry (SWV) techniques for monitoring the behavior of the redox probe. To survey the morphological pattern and surface structural characterizations, the Field Emission-Scanning Electron Microscopy (FE-SEM) has been applied. In summary, the gold nanoparticles supported by histidine was checked for immobilization of a Brucella-specific probe and detection of hybridization with a variety of sequences with a high sensitivity. The high sensitivity would be related to more favorable conformation and deflection angle of the probe for an efficient hybridization, higher surface concentration of the probe, and/or enhanced diffusion regime. These lead to better display of the entangled target sequences arising from the nanobiotechnology. The proposed genosensor showed a perfect distinction between complementary, non-complementary and mismatched DNA sequences. The engineered genosensor for detection of the complementary/non-complementary sequences were assayed. The fabricated genosensor was evaluated for the assay of the bacteria in the cultured and human samples with and without polymerase chain reactions (PCR). The genosensor could detect the complementary sequence in linear concentration range of 1 × 10−1 to 1 × 10−10 μM, and a low limit of quantification 0.1 pM.

Conformal Peeling of Device-on-Substrate System in Flexible Electronic Assembly

Continuous peeling of thin chips and flexible devices from a donor to an acceptor is critical for high-efficiency roll-to-roll (R2R) manufacturing of flexible electronics. Here, we propose an R2R conformal peeling technique for the flexible device-on-substrate electronic assembly. First, a mechanical model is established for flexible multilayer structures conformed on curved surface, such as peeling blade, and the corresponding analytical solution of the interfacial shear stress and peeling stress of the adhesive layer is given. Then, the influence of material property and geometrical size of the device (Young’s modulus of different layers and thickness of various layers), the geometric shape of peeling blade (peeling radius and conformal angle), and R2R process parameters (tension and speed of substrate) are analyzed by the theoretical model and experimental test. The peelability law of delaminating devices from the substrate is established for the conformal peeling process. Finally, the design method for a peeling blade is proposed, and the core is to determine the diameter of the peeling blade. It is proofed by the peeling experiment of multilayer electronic devices in the packaging of radio-frequency identification tags.

Hybrid organo-montmorillonite produced by simultaneous intercalation of phosphonium and ammonium/amine based surfactants

This study describes the preparation and characterization of hybrid organo-modified montmorillonite (OMt) produced by intercalation of phosphonium-based plus ammonium and/or amine-based surfactants, aiming to improve thermal and compatibility properties for the manufacture of clay mineral polymer nanocomposites (CPN). The choice of the surfactants was based on previous studies, which have pointed out that the phosphonium-based surfactant provided the clay mineral a high thermal stability but low d001-value and hydrophobicity. On the other hand, ammonium-based compounds presented inverse properties, i.e., low thermal stability and high d001-value. The present work was supported by design of experiments (DOE) considering different surfactant concentrations. The materials were analyzed by thermogravimetric analysis (TGA) to evaluate the thermal stability and relative reactional yield, by X-ray diffraction (XRD), to evaluate the surfactant intercalation by d001 of the clay, also by Fourier-transform infrared spectroscopy (FTIR) and contact angle, to verify the components interaction and the hydrophobicity. The hybrid montmorillonites presented intermediate properties, as thermal stability and basal space, when compared with the clay modified by the single modifiers. The intercalated species were arranged in paraffin-type structure and their conformation and tilt angle changed by increasing the ammonium concentration. Statistical analysis allowed knowing the concentration effects of each surfactant on hybrid materials. From the statistical models, an optimized formulation considering the maximum d001-value, Tonset (initial temperature of thermal degradation) and yield responses was prepared, which had its significance tested by Anova and F-test, and was validated by experimental values.

Objective evaluation of female feet and leg joint conformation at time of selection and post first parity in swine1.

Feet and legs of replacement females were objectively evaluated at selection, i.e., approximately 150 d of age (n = 319) and post first parity, i.e., any time after weaning of first litter and before second parturition (n = 277) to 1) compare feet and leg joint angle ranges between selection and post first parity; 2) identify feet and leg joint angle differences between selection and first 3 wk of second gestation; 3) identify feet and leg joint angle differences between farms and gestation days during second gestation; and 4) obtain genetic variance components for conformation angles for the two time points measured. Angles for carpal joint (knee), metacarpophalangeal joint (front pastern), metatarsophalangeal joint (rear pastern), tarsal joint (hock), and rear stance were measured using image analysis software. Between selection and post first parity, significant differences were observed for all joints measured (P < 0.05). Knee, front and rear pastern angles were less (more flexion), and hock angles were greater (less flexion) as age progressed (P < 0.05), while the rear stance pattern was less (feet further under center) at selection than post first parity (only including measures during first 3 wk of second gestation). Only using post first parity leg conformation information, farm was a significant source of variation for front and rear pasterns and rear stance angle measurements (P < 0.05). Knee angle was less (more flexion; P < 0.05) as gestation age progressed. Heritability estimates were low to moderate (0.04-0.35) for all traits measured across time points. Genetic correlations between the same joints at different time points were high (>0.8) between the front leg joints and low (<0.2) between the rear leg joints. High genetic correlations between time points indicate that the trait can be considered the same at either time point, and low genetic correlations indicate that the trait at different time points should be considered as two separate traits. Minimal change in the front leg suggests conformation traits that remain between selection and post first parity, while larger changes in rear leg indicate that rear leg conformation traits should be evaluated at multiple time periods.

Unusual fluorescent photoswitching of imidazole derivatives: the role of molecular conformation and twist angle controlled organic solid state fluorescence.

Molecular photoswitching, light induced reversible color/fluorescence modulation, has mostly been realized in organic molecules via E/Z isomerization of azobenzenes and stilbenes and ring opening/closing reactions of spiropyrans and diarylethenes. We report here new fluorescent molecular photoswitches based on triphenylamine (TPA)-imidazole derivatives, N-phenyl-N-(4-(1,4,5-triphenyl-1H-imidazol-2-yl)phenyl)benzenamine (NTPB) and N-phenyl-N-(4-(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)benzenamine (NPPB), that exhibited light induced reversible fluorescence switching via conformational change from a twisted molecular structure to more planar. NTPB and NPPB in CHCl3 showed red shift of absorption and fluorescence upon UV light irradiation whereas white light exposure reversed both absorption as well as fluorescence. The role of the TPA-imidazole twisted molecular structure in photoswitching was established based on structure property, computational and photophysical studies. The isobestic point observed in time dependent fluorescence change under UV light irradiation clearly demonstrated the presence of two different conformational isomers. Interestingly, polymorphism and torsion angle (τ) dependent fluorescence of NTPB and NPPB in the solid state also supported the role of the twisted molecular structure of TPA-imidazole in fluorescence switching/tuning. Interestingly, NTPB showed fluorescence photoswitching in the solid state also whereas rigid phenanthrene based NPPB did not show fluorescence photoswitching. Thus the present studies provide structural insight for designing a new type of fluorescent organic molecular photoswitches based on conformational modulation that could be of potential interest in optoelectronic devices.

Direction-of-Arrival Estimation in Conformal Microstrip Patch Array Antenna

The direction-of-arrival (DOA) estimation of a conformal antenna array with directive elements is studied in this communication. The two-dimension Cramer–Rao lower bound (CRLB) is derived for a conformal antenna array by using the active directive radiation patterns of the array elements and compared with the isotropic ones. Moreover, the MUSIC method is used to confirm the CRLB results. Without loss of generality, the CRLB of a truncated hexagonal pyramid conformal array with seven patches is investigated which verify the significant effect of the directive elements in the DOA estimation accuracy rather than that of the isotropic ones. The simulation results prove that this conformal array achieves better DOA estimation performance rather than that of the planar array antenna especially at the horizon angles. Moreover, the conformal antenna array tilt angle is studied to achieve the optimum conformal array structure which depicts a tradeoff between the DOA estimation accuracy at low and high $\theta $ incident angles.

Crystal structures of three 3-chloro-3-methyl-2,6-di-aryl-piperidin-4-ones.

The syntheses and crystal structure of 3-chloro-3-methyl-r-2,c-6-di-phenyl-piperidin-4-one, C18H18ClNO, (I), 3-chloro-3-methyl-r-2,c-6-di-p-tolyl-piperidin-4-one, C20H22ClNO, (II), and 3-chloro-3-methyl-r-2,c-6-bis-(4-chloro-phen-yl)piperidin-4-one, C18H16Cl3NO, (III), are described. In each structure, the piperidine ring adopts a chair conformation and dihedral angles between the mean planes of the phenyl rings are 58.4 (2), 73.5 (5) and 78.6 (2)° in (I), (II) and (III), respectively. In the crystals, mol-ecules are linked into C(6) chains by weak N-H⋯O hydrogen bonds and C-H⋯π inter-actions are also observed.

Conformational Angles and Properties of Ω-Amino Acids in Protein Folding

Conformational Angles and Properties of Ω-Amino Acids in Protein Folding