Position Of Attachment Research Articles

Insights into Kinesin-1 Stepping from Simulations and Tracking of Gold Nanoparticle-Labeled Motors

High-resolution tracking of gold nanoparticle-labeled proteins has emerged as a powerful technique for measuring the structural kinetics of processive enzymes and other biomacromolecules. These techniques use point spread function (PSF) fitting methods borrowed from single-molecule fluorescence imaging to determine molecular positions below the diffraction limit. However, compared to fluorescence, gold nanoparticle tracking experiments are performed at significantly higher frame rates and utilize much larger probes. In the current work, we use Brownian dynamics simulations of nanoparticle-labeled proteins to investigate the regimes in which the fundamental assumptions of PSF fitting hold and where they begin to break down. We find that because gold nanoparticles undergo tethered diffusion around their anchor point, PSF fitting cannot be extended to arbitrarily fast frame rates. Instead, camera exposure times that allow the nanoparticle to fully populate its stationary positional distribution achieve a spatial averaging that increases fitting precision. We furthermore find that changes in the rotational freedom of the tagged protein can lead to artifactual translations in the fitted particle position. Finally, we apply these lessons to dissect a standing controversy in the kinesin field over the structure of a dimer in the ATP waiting state. Combining new experiments with simulations, we determine that the rear kinesin head in the ATP waiting state is unbound but not displaced from its previous microtubule binding site and that apparent differences in separately published reports were simply due to differences in the gold nanoparticle attachment position. Our results highlight the importance of gold conjugation decisions and imaging parameters to high-resolution tracking results and will serve as a useful guide for the design of future gold nanoparticle tracking experiments.

Numerical simulation of the flow characteristics inside a novel plasma spray torch

A novel direct current non-transferred arc plasma torch that can generate a long, stable and silent plasma jet of over 350 mm in length into ambient air is studied by numerical modelling. Numerical simulation of the plasma torch operating in the current of 160 A with a mixture of 70% nitrogen and 30% argon in volume at three different gas flow rates (8.5 SLPM, 10 SLPM and 14 SLPM) are performed in a 3D domain. The renormalization group method is employed to model the turbulent flow inside the plasma torch, particularly the torch’s novel channel structure. The results show that a narrow circular gap at the boundary layer of the cathode led to a region of high flow constriction and large pressure and velocity gradients. The anode counts with a novel trumpet-like structure that separates the flow in the channel and induces turbulent fluctuations in the direction transverse to the flow, which can disrupt and decrease the cold boundary layer around the arc column. The arc attachment position that obtained in simulation is in agreement with the experiment observation. The maximum velocity at the torch nozzle in simulation is increased and the length of the plasma jet in experiment is decreased with the increasing of the total gas flow rates from 8.5 SLPM, 10 SLPM to 14 SLPM. However, the maximum temperature at the torch nozzle in three different gas flow rates are varied slightly. Our results suggest that generation of a long and stable plasma jet downstream of the nozzle exit should not only focus on a relatively low gas flow rate, but depend instead on the aerodynamic characteristics of the channel flow, particularly in the anode region and downstream of the anode.

Protein Materials Engineering with DNA.

Proteins are a class of nanoscale building block with remarkable chemical complexity and sophistication: their diverse functions, shapes, and symmetry as well as atomically monodisperse structures far surpass the range of conventional nanoparticles that can be accessed synthetically. The chemical topologies of proteins that drive their assembly into materials are central to their functions in nature. However, despite the importance of protein materials in biology, efforts to harness these building blocks synthetically to engineer new materials have been impeded by the chemical complexity of protein surfaces, making it difficult to reliably design protein building blocks that can be robustly transformed into targeted materials. Here we describe our work aimed at exploiting a simple but important concept: if one could exchange complex protein-protein interactions with well-defined and programmable DNA-DNA interactions, one could control the assembly of proteins into structurally well-defined oligomeric and polymeric materials and three-dimensional crystals. As a class of nanoscale building block, proteins with surface DNA modifications have a vast design space that exceeds what is practically and conceptually possible with their inorganic counterparts: the sequences of the DNA and protein and the chemical nature and position of DNA attachment all play roles in dictating the assembly behavior of protein-DNA conjugates. We summarize how each of these design parameters can influence structural outcome, beginning with proteins with a single surface DNA modification, where energy barriers between protein monomers can be tuned through the sequence and secondary structure of the oligonucleotide. We then explore challenges and progress in designing directional interactions and valency on protein surfaces. The directional binding properties of protein-DNA conjugates are ultimately imposed by the amino acid sequence of the protein, which defines the spatial distribution of DNA modification sites on the protein. Through careful design and mutagenesis, bivalent building blocks that bind directionally to form one-dimensional assemblies can be realized. Finally, we discuss the assembly of proteins densely modified with DNA into crystalline superlattices. At first glance, these protein building blocks display crystallization behavior remarkably similar to that of their DNA-functionalized inorganic nanoparticle counterparts, which allows design principles elucidated for DNA-guided nanoparticle crystallization to be used as predictive tools in determining structural outcomes in protein systems. Proteins additionally offer design handles that nanoparticles do not: unlike nanoparticles, the number and spatial distribution of DNA can be controlled through the protein sequence and DNA modification chemistry. Changing the spatial distributions of DNA can drive otherwise identical proteins down distinct crystallization pathways and yield building blocks with exotic distributions of DNA that crystallize into structures that are not yet attainable using isotropically functionalized particles. We highlight challenges in accessing other classes of architectures and establishing general design rules for DNA-mediated protein assembly. Harnessing surface DNA modifications to build protein materials creates many opportunities to realize new architectures and answer fundamental questions about DNA-modified nanostructures in both materials and biological contexts. Proteins with surface DNA modifications are a powerful class of nanomaterial building blocks for which the DNA and protein sequences and the nature of their conjugation dictate the material structure.

High Risk of Tunnel Convergence in Combined Anterior Cruciate Ligament Reconstruction and Lateral Extra-articular Tenodesis

Background: Lateral extra-articular tenodesis (LET) is being increasingly added to primary and revision anterior cruciate ligament (ACL) reconstruction to address residual anterolateral rotatory instability. However, currently there is a lack of knowledge on how close the femoral tunnels are when combining these procedures. Purpose/Hypotheses: To assess the risk of tunnel convergence in combined ACL and LET procedures using 2 different surgical techniques (Lemaire and MacIntosh). It was hypothesized that the risk of tunnel convergence would be greater when using the more distally located Lemaire position. The authors further hypothesized that tunnel proximity would be influenced by knee size. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen cadaveric knees were used for this study. In each specimen, an anatomic ACL femoral tunnel and 2 LET tunnels were drilled using the Lemaire and MacIntosh positions, respectively. After knee dissection, minimal distances between each ACL and LET tunnel were directly measured on the lateral femoral cortex. Furthermore, computed tomography scans were obtained to measure intertunnel convergence and lateral femoral condyle (LFC) width. On the basis of the average LFC width, knees were divided into large and small knees to determine a relationship between knee size and tunnel convergence. Results: Convergence of ACL and LET tunnels occurred in 7 of 10 cases (70%) using the Lemaire attachment position. All tunnel collisions occurred directly on the lateral femoral cortex, while intertunnel (intramedullary) conflicts were not observed. Collisions emerged in both small (n = 4) and large (n = 3) knees. Critical tunnel convergence did not occur using the MacIntosh position. The mean minimal distance between the LET and ACL tunnel using the Lemaire and MacIntosh positions was 3.1 ± 4.6 mm and 9.8 ± 5.4 mm, respectively. Conclusion: Tunnel convergence was more frequently observed in combined ACL and LET reconstruction using the Lemaire technique, independent of the knee size. LET femoral tunnel positioning according to the MacIntosh reconstruction was not associated with tunnel collision. Clinical Relevance: These findings help to raise the awareness for the risk of tunnel convergence in combined ACL and LET procedures. Surgeons may contemplate adjustments on the ACL femoral tunnel drilling technique or fixation device when applying an additional Lemaire procedure. However, in the absence of clinical outcome studies comparing different LET techniques, it remains unclear which technique is superior in a clinical setting.

Effect of structural isomerism in BODIPY based donor-acceptor co-polymers on their photovoltaic performance

Borondipyrromethene or BODIPY can be incorporated into the polymer backbone through either the α (or 2,6) positions or the β (3,5) positions and hence resulting in polymers exhibiting structural isomerism. In this work two pairs of such isomeric D-A polymers formed by copolymerization of BODIPY with benzodithiophene (P1 and P2) and fluorene (P3 and P4) separately are reported along with structure property correlation. Depending on the positions of attachment of the BODIPY unit in the isomeric polymers, the geometry of the polymer backbone is either coiled or linear which in turn affects physical properties such as thermal stability, solubility and absorption, electronic properties such as delocalization of molecular orbitals, HOMO-LUMO energy levels and band gap. Though the charge carrier mobility seems to remain unaffected due to the isomerism of the polymer backbone, the α connected polymers perform better than the β connected polymers when used as electron acceptor along with P3HT in all polymer solar cells. This is also the first instance of application of BODIPY copolymers as electron acceptor in organic solar cells.

Flying watch: an attachable strength enhancement device for long-reach robotic arms

A long-reach robotic arm is useful for applications such as nuclear plant decommissioning, inspection, and firefighting. However, for such arms, a small external reaction force can result in large loads on proximal arm actuators because of long moment arms. This problem was previously solved by specialized arm designs that compensate external reaction forces. However, these arm designs are hard to be applied to other arms or customized to different missions. To overcome these difficulties, in this paper, we propose a modular thrust generating concept inspired by wristwatch designs, called flying watch, which can be attached to a robotic arm with mission-dependent attachment styles (attachment positions and orientations) and cooperate with actuators to enhance arm strength. We first introduce flying watch concept, design, and dynamics. Then we propose two levels of watch-actuator cooperation in quasistatic situations by introducing a problem called Watch Actuator Cooperation for Arm Enhancement (WACAE) and providing an example solution. The first level of cooperation is only watches adapt their thrusts to minimize actuator loads, which is generally applicable to varieties of arms. The second level cooperation is that not only do the watches adapt their thrusts but also the actuators cooperatively position the watches to optimal positions and orientations to counteract external reaction forces, which is suitable for redundant arms and can counteract external reaction forces more effectively. Finally, we present simulations to verify that flying watches can significantly reduce actuator loads using both levels of watch-actuator cooperation (the first level by 36.9% and the second level by 43.7%).

Rigid and Flexible Bis-Porphyrinic Tweezers: Efficient Molecular Recognition of Bidentate Bases.

Increasing efforts are devoted to the synthesis of cofacial bis-porphyrinic tweezers able to complex various bidentate guests through axial coordination of the Zn(II) porphyrins by the two nitrogen atoms. Elaboration of rigid receptors appeared up to now as the ideal way to pre-organize a bis-porphyrinic cavity and increase the stability of the formed host/guest complexes. However, the choice of using rigid spacer to attach the two porphyrins together may cost a lot as far as solubility and stability are concerned. The synthetic pathways necessary to achieve the synthesis of rigid systems are frequently long and tedious. We report here the synthesis and studies of new flexible bis-porphyrinic tweezers bearing uridine as linkers and offering pre-organized cavities able to welcome bidentate guests with extremely high association constants. As part of our studies concerning complexation of bidentate Lewis bases by bis-porphyrinic tweezers, we have synthesized two new bis-porphyrins bearing a flexible nucleosidic linker. Both uridine and 2’-deoxyuridine spacers were chosen on account of some observations we made a few years ago on the unexpected blocked conformations adopted by a pentaporphyrin consisting of four Zn(II) porphyrins attached to a central free-base porphyrin by four nucleosidic linkers. Since we observed no such blocked conformations in other flexible pentaporphyrins, we thought this might be due to the nucleosidic nature of the linkers. We thus synthesized two dimers, which differ by the attachment positions of the two porphyrins. The ability of these two tweezers to accomodate guests was investigated through ligand binding studies carried out in dichloromethane with DABCO as bidentate base. The complexation of DABCO by these dimers was monitored by UV-visible spectrophotometric titration in CH2Cl2. The binding constants between these two tweezers and DABCO were calculated from UV-visible spectroscopic data. These association constants are unexpectedly increased by more than one order of magnitude as compared to the association constants of the same bidentate ligand with a reference Zn(II) mono-porphyrin. This enhanced stability of the complexes may be ascribed to a pre-organization of the bis-porphyrinic tweezers forming a cavity, and provides convincing evidence that the bidentate base is inserted into the cavity of the dimers via host/guest interactions. We demonstrated that similar association constants can be obtained with flexible tweezers bearing uridine as linker and rigid tweezers. However, the stability of these flexible complexes isn’t as convincing as for our rigid tweezers bearing a tris-anthracenic spacer since the addition of an excess of DABCO destroys all the flexible complexes. Molecular modelling of one of the flexible tweezers and its 1/1 complex with DABCO is represented below, as well as our rigid tweezers bearing a tris-anthracenic spacer. Acknowledgements This work was supported by the CNRS and the French Ministry of Research. Figure 1

Habitat Suitability for Hoya spp. (Apocynaceae) in The Bodogol Conservation Area, West Java

Hoya is a tropical flowering plant that has great potential as an export commodity. It needs to be cultivated to ensure its sustainability in nature. Information about the suitable habitat of Hoya was not widely known yet. This study aimed to compare the habitat characteristics of several species of Hoya. The research was conducted by exploring the sample plots determined by purposive sampling based on the differences of habitat characteristics. The biotic components observed were phorophyte species type and the number of individual of each Hoya species. The abiotic components measured in each plot were altitude and geographical position, air temperature, humidity, light intensity, wind speed, and canopy cover. Hoya ‘s diversity was analyzed using the Shannon Winner Index. Environmental factor data and biotic factors were analyzed with Canoco for Windows 4.5 software. There were 6 species of Hoya namely Hoya multiflora, Hoya imperialis, Hoya vitellinoides, Hoya hasseltii, Hoya campanulata and Hoya lacunosa found in this study. The highest biodiversity index was obtained in an altitude of 700-800 m.a.s.l (H’=1.41) and in hillsides area (H’=1.3). Hoya ‘s most frequent phorophyte was Schima wallichii. Factors affecting the presence of Hoya in the phorophytes were the position of attachment to the main stem and the rough surface characteristics of the tree. Hoya ‘s preference place was on the bark fracture. Abiotic factors that most influencing the existence of Hoya were air humidity and canopy cover. The data of this research can be used as basic information for carried out the conservation efforts and cultivation strategy in the future.

Influence of clinical experience on accuracy of virtual orthodontic attachment bonding in comparison with the direct procedure.

To compare the accuracy of bonding orthodontic attachments in a digital environment with the direct bonding procedure depending on the level of the orthodontist's clinical experience. A total of 1120 artificial teeth of 40 identical models (20 solid sets + 20 digital sets) were divided into four groups: (1) direct bonding (experienced clinicians). (2) direct bonding (postgraduate students), (3) virtual bonding (experienced clinicians), and (4) virtual bonding (postgraduate students). The differences in individual position of the placed attachments were measured after three-dimensional superimposition of the models using customized software. In the interoperator comparison, experienced clinicians were more exact than postgraduate students in virtual bonding in the angular dimension. Between the bonding techniques, virtual bonding was more accurate than the direct technique. The prevalence of errors was higher in the direct procedure than virtual bonding, and the errors were more significant in the premolar and molar teeth. Clinical experience had a positive influence in achieving a higher rate of correctness/accuracy in the angular dimension only during virtual bonding. Virtual bonding was more accurate than direct bonding in the vertical and horizontal dimensions. Early diagnosis of errors in the bonding positions of attachments could be of benefit to both clinicians and patients by predicting discrepancies that may lead to undesirable orthodontic movements.

Abstract B147: From bioactive small molecule to an identified protein target: A new method combining stochastic photomodification with a synthetic antibody mimetic

Abstract The renaissance of phenotypic screening leads to the discovery of biologically active small molecules resulting in a high need to quickly and efficiently identify their protein target. This is most commonly done by a preparation of an affinity probe for the target pull-down, which requires time-consuming structure-activity relationship studies to identify proper position for an attachment of an affinity anchor with necessary linker. We set out to circumvent this step altogether and prepare stochastic conjugates that would enable fast target identification without prior structural information or testing of suitable linker attachment position. We suggest that they could be used also for the identification of unknown targets of phenotypically active compounds as well as off-targets of established active compounds. To test the new approach, we selected several model protein targets – glutamate carboxypeptidase II (GCPII, also known as prostate specific membrane antigen, PSMA) expressed in prostate cancer, fibroblast activation protein (FAP) in tumor stroma, and aspartic protease family, specifically pepsin, cathepsin D and HIV protease. For each, we stochastically modified their corresponding known biologically active small-molecule inhibitors using a linker with a photoactivatable diazirine group. Resulting reaction mixture contained various inhibitor isomers, whose biologic activity was not compromised by the position of the linker attachment as well as those where it was. Afterwards, the reaction mixtures were conjugated to N-(2-hydroxypropyl)methacrylamide copolymers (called iBodies) carrying biotin and a fluorophore, which were used as fully synthetic antibody mimetics. In all cases, stochastic polymer conjugates were able to pull-down the corresponding target protein from cell lysates. For the GCPII conjugate, we then analyzed the pulled-down proteins by mass spectrometry, which clearly identified GCPII as the target protein of the conjugate, even with no prior knowledge needed. For GCPII and FAP, which are cell surface receptors, those same conjugates were able to visualize the proteins on cells both in confocal microscopy and flow cytometry. On a model case of GCPII we decided to identify the position of the “productive” linker attachment so that it would allow rational synthesis for future use. Using HPLC, we separated the reaction mixture into several fractions, each enriched in a specific linker attachment position. As expected, the fractions differed in binding properties compared to the whole mixture. The position of the linker attachment was determined by mass spectrometry for selected active and inactive fractions. The identified linker positions and activity of the compounds corresponded to the known mode of binding of the small molecule into the active site of GCPII. Polymer conjugates prepared from the most favorable fraction had improved binding properties. This “improved” conjugate allowed more efficient isolation and subsequent identification of GCPII by mass spectrometry. These results show that stochastic modification of bioactive small molecule combined with the avidity effect on iBodies allowed us to avoid lengthy structure-activity-relationship studies and enabled identification of protein target and its visualization using a single conjugate. This technology might contribute to fast and facile identification of protein targets of phenotypically active small molecules. This work was supported by Grant No. GA16-02938S from the Grant Agency of the Czech Republic, InterBioMed Project LO 1302 from the Ministry of Education of the Czech Republic, and by the Charles University, project GA UK No. 1510-243-250045. Citation Format: Kristyna Blazkova, Petr Šimon, Tomáš Knedlík, Petra Dvořáková, Anna Březinová, Libor Kostka, Vladimír Šubr, Jan Konvalinka, Pavel Šácha. From bioactive small molecule to an identified protein target: A new method combining stochastic photomodification with a synthetic antibody mimetic [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B147.

Structural Optimization of α-Synuclein Fibril Growth Inhibitors

Aggregation of alpha-synuclein (αSyn) is involved in the development of Parkinson's disease, a severe neurodegenerative disorder that has no cure at the moment. Recently we showed that bulky molecules binding to the ends of αSyn fibrils can efficiently slowdown fibril growth and developed the first rationally designed inhibitor working on this principle [1]. The constructed fusion protein, consisting of a bulky protein moiety attached to the C-terminus of αSyn molecule, has IC50 of 850 nM. Nevertheless, its inhibitor efficiency can be further improved by increasing steric hindrance and affinity to the fibril end. We studied the structure-activity relationship in a series of inhibitors focusing on the structure, size, and position of the bulky group. We prepared 12 protein-based inhibitors varying: a) sequence of αSyn moiety to improve binding of inhibitor to the fibril end; b) structure of bulky moieties; c) attachment position of the bulky group to αSyn to improve steric hindrance. Their inhibition activities were tested in a kinetic ThT-based assay and compared by IC50 values. Decreasing the electrostatic repulsion between the fibril end and inhibitor molecule by deleting αSyn C-terminus or neutralizing its charge significantly improved inhibitor efficiency (IC50=500 nM and 700 nM, respectively). Changing the bulky group structure and positioning it at the N-terminus allowed us to prepare an inhibitor with IC50 340 nM, that is the most active αSyn fibril growth inhibitor to the best of our knowledge. Our structure-activity relationship studies provide background for rational design of protein-based inhibitors of αSyn fibrillization targeting ends of fibrils and having potential to reach low nanomolar IC50. [1] V V Shvadchak, K Afitska, D A Yushchenko, Angew Chem Int Ed Engl, 2018, 57, 5690.

Insights into Kinesin-1 Stepping Dynamics from Brownian Dynamics Simulations and High-Resolution Tracking of Gold Nanoparticle-Labeled Motors

Abstract High-resolution tracking of gold nanoparticle-labeled proteins has emerged as a powerful technique for measuring the structural kinetics of processive enzymes and other biomacromolecules. These techniques use point-spread-function fitting methods borrowed from single-molecule fluorescence imaging to determine molecular positions below the diffraction limit. However, compared to fluorescence, gold nanoparticle tracking experiments are performed at significantly higher frame rates and utilize much larger probes. In the current work, we use Brownian dynamics simulations of nanoparticle-labeled proteins to investigate the regimes in which the fundamental assumptions of point-spread-function fitting hold and where they begin to break down. We find that because gold nanoparticles undergo tethered diffusion around their anchor point, point spread function fitting cannot be extended to arbitrarily fast frame rates. Instead, camera exposure times that allow the nanoparticle to fully populate its stationary positional distribution achieve a spatial averaging that increases fitting precision. We furthermore find that changes in the rotational freedom of the tagged protein can lead to artifactual translations in fitted particle position. Finally, we apply these lessons to dissect a standing controversy in the kinesin field over the structure of a dimer in the ATP waiting state. Combining new experiments with simulations, we determine that the rear kinesin head in the ATP waiting state is unbound but not displaced from its previous microtubule binding site, and that apparent differences in separately published reports were simply due to differences in the gold nanoparticle attachment position. Our results highlight the importance of gold conjugation decisions and imaging parameters to high-resolution tracking results, and will serve as a useful guide for the design of future gold nanoparticle tracking experiments.

Halal Emotional Attachment on Repurchase Intention

This research examines the position of emotional attachment as a mediation of the influence between halal awareness, halal logos and food ingredients composition on repurchase intention of buying halal products. This research brings sample of those who have consumed or have purchased halal products. Due to the population is unknown, by using the Lameshow formula, a total of 384 respondents were obtained. Halal emotional attachment, as this research shows, is able to play a salient role as a mediator of the influence among three aforementioned variables on repurchase intention. This research would have been an effort to contribute marketing halal products as a new concept of the emotional attachment. Keywords: halal, Lameshow, marketing halal, repurchase intention

Algorithm for evaluating tissue circulation based on spectral changes in wearable photoplethysmography device

Tissue circulation monitoring is an effective method to detect compromised circulation in time after tissue transplantation. Use of flexible photoplethysmography (PPG) devices for tissue circulation monitoring allows the continuous measurement of signals at multiple positions on the tissue. An algorithm of tissue circulation evaluation that considers motion artifacts is also necessary for such devices, although conventional motion evaluation algorithms cannot be used with weak PPG signals during compromised circulation. In this study, we developed an algorithm that discriminates between three states – normal circulation, compromised circulation, and artifacts. We measured the signals from different attachment positions on eight healthy volunteers for investigating the variation of signals between these positions. We then applied the algorithm to evaluate normal and compromised circulations during a resting position and with motion events. The efficiency of the algorithm was evaluated based on the data usage and specificity calculated from one-week continuous measurements. The results show that, for all volunteers, the algorithm correctly identified normal and compromised circulation signals even when the signal was partially corrupted due to motion artifacts. Seriously corrupted data were identified as artifacts. Data usage and specificity during one-week monitoring on volunteers were 89.7 ± 3.0% and 99.3 ± 0.6%, respectively. The results indicate that our device achieves effective one-week monitoring on tissues and our algorithm correctly evaluates tissue circulation with wearable PPG devices. Our device and algorithm have the potential to assist medical staff during post-operative observation of transplanted tissues.

Synthesis, computational studies, tyrosinase inhibitory kinetics and antimelanogenic activity of hydroxy substituted 2-[(4-acetylphenyl)amino]-2-oxoethyl derivatives

The over expression of melanogenic enzymes like tyrosinase caused many hyperpigmentaion disorders. The present work describes the synthesis of hydroxy substituted 2-[(4-acetylphenyl)amino]-2-oxoethyl derivatives 3a–e and 5a–e as antimelanogenic agents. The tyrosinase inhibitory activity of synthesized derivatives 3a–e and 5a–e was determined and it was found that derivative 5c possesses excellent activity with IC50 = 0.0089 µM compared to standard kojic acid (IC50 = 16.69 µM). The presence of hydroxyl groups at the ortho and the para position of cinnamic acid phenyl ring in compound 5c plays a vital role in tyrosinase inhibitory activity. The compound 5d also exhibited good activity (IC50 = 8.26 µM) compared to standard kojic acid. The enzyme inhibitory kinetics results showed that compound 5c is a competitive inhibitor while 5d is a mixed-type inhibitor. The mode of binding for compounds 5c and 5d with tyrosinase enzyme was also assessed and it was found that both derivatives irreversibly bind with target enzyme. The molecular docking and molecular dynamic simulation studies were also performed to find the position of attachment of synthesized compounds at tyrosinase enzyme (PDB ID 2Y9X). The results showed that all of the synthesized compounds bind well with the active binding sites and most potent derivative 5c formed stable complex with target protein. The cytotoxicity results showed that compound 5c is safe at a dose of 12 µg/mL against murine melanoma (B16F10) cells. The same dose of 5c was selected to determine antimelanogenic activity; the results showed that it produced antimelenogenic effects in murine melanoma (B16F10) cells. Based on our investigations, it was proposed that compound 5c may serve as a lead structure to design more potent antimelanogenic agents.

Orientational phase behavior of polymer-grafted nanocubes.

Surface functionalization of nanoparticles with polymer grafts was recently shown to be a viable strategy for controlling the relative orientation of shaped nanoparticles in their higher-order assemblies. In this study, we investigated in silico the orientational phase behavior of coplanar polymer-grafted nanocubes confined in a thin film. We first used Monte Carlo simulations to compute the two-particle interaction free-energy landscape of the nanocubes and identify their globally stable configurations. The nanocubes were found to exhibit four stable phases: those with edge-edge and face-face orientations, and those exhibiting partially overlapped slanted and parallel faces previously assumed to be metastable. Moreover, the edge-edge configuration originally thought to involve kissing edges instead displayed partly overlapping edges, where the extent of the overlap depends on the attachment positions of the grafts. We next formulated analytical scaling expressions for the free energies of the identified configurations, which were used for constructing a comprehensive phase diagram of nanocube orientation in a multidimensional parameter space comprising of the size and interaction strength of the nanocubes and the Kuhn length and surface density of the grafts. The morphology of the phase diagram was shown to arise from an interplay between polymer- and surface-mediated interactions, especially differences in their scalings with respect to nanocube size and grafting density across the four phases. The phase diagram provided insights into tuning these interactions through the various parameters of the system for achieving target configurations. Overall, this work provides a framework for predicting and engineering interparticle configurations, with possible applications in plasmonic nanocomposites where control over particle orientation is critical.

Spectroscopic differentiation and chromatographic separation of regioisomeric indole aldehydes: Synthetic cannabinoids precursors

The compounds in this study are the six regioisomeric 2-, 3-, 4-, 5-, 6- and 7-formyl indoles and the corresponding six regioisomeric N-n-pentylindole aldehydes. These compounds can serve as precursor chemicals and synthetic intermediates for a number of synthetic cannabinoid drugs. These two sets (the six regioisomeric indole aldehydes as well as the six regioisomeric pentylindole aldehydes) each have identical elemental compositions and differ in the position of attachment of the aldehyde group on the indole ring.The electron ionization mass spectra for the indole aldehydes were essentially identical. However, the vapor phase infrared spectra showed differences in the absorption frequencies for the NH and carbonyl groups based on intramolecular interactions. The associated NH absorption band occurs as low as 3467 cm−1 while the free band is as high as 3517 cm−1. The aldehyde carbonyl band for the indole aldehydes varies from 1713 cm−1 to 1686 cm−1. Substitution of the aldehyde group on the pyrrole ring for the N-n-pentylindole aldehydes yields lower carbonyl absorption bands. The EI mass spectra for the pentylindole aldehydes are identical with little information for differentiation among these six regioisomeric compounds. The six compounds were separated on a capillary column using gas chromatography and the elution order appears to be related to the steric crowding of the indole ring substituents.

Individualization of Musculoskeletal Model for Analyzing Pelvic Floor Muscles Activity Based on Gait Motion Features

Stress urinary incontinence (SUI) is a typical quality of life disease in women. The strengthening of the pelvic floor muscle (PFM) is considered effective to prevent this. Specifically, PFM activity is affected by individual pelvic shape and posture. Therefore, it is necessary to analyze muscle activity by considering the individual differences. In this study, individual pelvic alignment was estimated from the feature values of natural gait via multiple regression analysis. In addition, individual pelvic feature points were derived from X-ray images and used to deform the standard model to obtain individual pelvic shapes. Results indicate that the residual averages of the estimated feature angles were less than 2° in most cases. Subsequently, measurements of the pelvis were obtained via MRI to evaluate the estimated pelvis shape. The results indicate that individual adaptation leads to muscle attachment positions, which are important in the muscle activity analysis, and closer to the true MRI value when compared to that of the standard pelvic model.

Evaluation of the permissible maximum angle of the tibial tunnel in transtibial anatomic posterior cruciate ligament reconstruction by computed tomography.

Excessive angle of the tibial tunnel may cause breakage of the posterior cortex in transtibial anatomic posterior cruciate ligament (PCL) reconstruction. However, a few studies have determined the permissible maximum angle of the tibial tunnel. The purpose of this study was to determine the permissible maximum angle of the tibial tunnel relative to the tibial plateau in transtibial anatomic PCL reconstruction and characterize the anatomic parameters of the tibial PCL attachment position. Computed tomography (CT) scans of a consecutive series of 408 adult knees with normal PCL attachment were measured. The parameters measured were the permissible maximum angle (PMA) of the 10mm-diameter tibial tunnel relative to the tibial plateau, the distance from the anterior orifice of the tibial tunnel to the tibial tuberosity (OTD), the anterior-posterior diameter (APD) of the tibial plateau, the distance from the center of PCL attachment site to the posterior edge of the tibial plateau (PPED), and the angle between the tibial plateau and the posterior tibial slope where the PCL insertion site was (PSA). Subgroup analysis was performed to determine the correlations between parameters, and sex, age, and height. The measurement reliability was evaluated by intraclass correlation coefficients (ICCs). The average value of PMA was 48.2 ± 5.4°, and it was not affected by sex, age, and height (P > 0.05). The values of OTD, APD, PPED, PSA, and height were significantly higher in males than females (OTD, P < 0.01; APD, P < 0.01; PPED, P < 0.01; PSA, P = 0.019; height, P < 0.01). With regard to age, we stratified the cases into three groups: the young (18-30years old), the middle-aged (31-45years old), and the elderly (46-60years old). The mean value of OTD, APD, and height were significantly lower in the elderly than that in the middle-aged (P < 0.01, P < 0.01, P < 0.01, respectively). With regard to height, we stratified the cases into three groups: ~ 1.65m (1), 1.66 ~ 1.75m (2), and 1.76m ~ (3). The mean value of OTD, APD, and PPED significantly increased with height, P < 0.05. The mean value of PSA was significant higher in II group than that in I group (P = 0.034). There should be a limit to the angle of the tibial tunnel in transtibial anatomic PCL reconstruction to prevent the fracture of posterior tunnel wall. The permissible maximum angle (PMA) of the 10mm-diameter tibial tunnel relative to the tibial plateau was 48.2°. Besides, the determination of the value of OTD, APD, PPED, and PSA could provide a clinical reference to insertion site, depth, and angle of the tibial drill guide in PCL reconstruction.

The canonical stewart platform as a six DOF pose sensor for automotive applications

The growing demand for prolonged fatigue life of automotive parts and components requires elaboration of their motion in Cartesian space having six degrees of freedom (DOF). Recently, the canonical Steward platform, consisting of six displacement sensors mounted on two parallel platforms, was introduced to comply with this request. In order to apply this pose sensor to automotive applications, the following two important matters are investigated in this study. First, update Jacobian is proposed as a faster and more stable numerical method to solve the forward kinematic problem without any iteration process. Second, the attachment position and initial configuration of the Stewart platform must be adjustable to avoid the interference with other components due to space constraints under the hood of automotive vehicle. In this case, however, the Jacobian matrix which converts six displacement components into a six DOF pose vector is prone to be ill-conditioned so that the converting accuracy becomes worse. The L1-norm of each row in the Jacobian matrix quantifies how much the error would be provoked according to the given kinematic geometry. Hence, it can be used here as a reliable error indicator. Furthermore, several numerical examples are discussed to demonstrate what to consider when designing a six DOF pose sensor for automotive applications.