Orientation Of Guest Research Articles

Performance of Particle Swarm Optimization in Predicting the Orientation of π-Conjugated Molecules Inside Carbon Nanotubes Compared with Density Functional Theory Calculations.

Particle swarm optimization (PSO) was employed to obtain the global minimum of host-guest structures consisting of a triiodobenzene molecule (BzI3) inside an armchair (m,m) nanotube (BzI3@(m,m)), whose host-guest interactions are approximated by Lennard-Jones (LJ) potentials. The host-guest structures obtained using the PSO-LJ method were then compared with those obtained through dispersion-corrected density functional theory (DFT) calculations to evaluate the performance of the PSO-LJ approach in predicting the guest orientation inside a tube. When the inner space of the host tube is limited for guest encapsulation, the PSO-LJ method can reproduce the DFT results of BzI3@(m,m) in terms of the guest orientation. Conversely, in nanotubes with a sufficiently large space to allow a guest to freely move, corresponding to weak tube confinement, the PSO-LJ method yields guest orientations that are different from those obtained through DFT calculations; however, both methods obtain energetically close guest orientations. Accordingly, PSO-LJ method-assisted DFT calculations can quickly provide energetically stable guest orientations in BzI3@(m,m) in weak tube confinement, which can be ignored in DFT calculations, where a single initial geometry is typically used.

Ferroelastic Control of the Multicolor Emission from a Triply Doped Organic Crystal.

Emission from crystalline organic solids is often quenched by nonemissive energy-transfer deexcitation processes. While dispersion of fluorophores in polymers or other hosts has been used to enhance the emission intensity, this strategy results in randomization of guest orientation and optical losses at grain boundaries. Here, we report the doping of inherently nonemissive single crystals of anilinium bromide with three fluorescent organic molecules. The doping process equips the crystal with emission characteristics that tune from blue to deep orange. The emission intensity can be reversibly modulated by ferroelastic twinning, which causes the material to function as a multiemissive force sensor. This approach opens up new pathways in the manipulation of emissive properties in organic crystals and may have substantial implications for optoelectronic devices and sensors.

Host–guest interactions in biocompatible anion-intercalated Mg-Al layered double hydroxides and their influence on L-lactate uptake

The mass production of human induced pluripotent stem cells (hiPSCs) is important in the area of regenerative medicine. During proliferation, stem cells metabolize D-glucose into L-lactate, the accumulation of which in a cell culture medium impairs the mass production of cells. It is therefore important to supply D-glucose and remove L-lactate from the cell culture medium to ensure that the stem cell mass culture can be achieved. In the present study, L-lactate-selective Mg-Al layered double hydroxide (LDH) adsorbents containing celL-culture-compatible exchangeable anions were designed. More specifically, different stem cell nutrients (i.e., L-alanyL-L-glutamine, L-glutamine, L-serine, L-methionine, L-cysteine, L-glutamate and α-ketoglutarate) and the cell culture buffer component (i.e., 4-(2-hydroxyethyl)-1-piperazineethanesulfonate (HEPES)) were incorporated into the Mg-Al LDHs via a rehydration method. The orientations of the organic guests and the host–guest interactions were characterized using a range of analytical and computational techniques. It was deduced that the L-lactate adsorption ability of the LDHs and the selectivity over D-glucose depended on a number of factors, including the charge density of the LDH guest relative to L-lactate, the guest orientation and the hydrogen bonds formed in the host–guest, guest–guest and guest–host–glucose complexes. Overall, this study provides insights into the design of effective and potentially biocompatible adsorbents for cell culture media regeneration to promote the cost-effective mass production of stem cells.

A study of azopyrimidine photoswitches and their interactions with cyclodextrins: When the guest governs the type of accommodation at the host

Azopyrimidines have recently emerged as a new class of photoswitches structurally similar to azobenzenes switching between trans and cis isomers. These compounds have a wide range of potential applications in photopharmacology, catalysis or as molecular devices, but their low solubility in water limits their biological applications. Nevertheless, this drawback could be overcome by their inclusion into supramolecular structures. To test this hypothesis, we prepared a series of azopyrimidines and investigated their structure, cis-trans isomerization and host-guest chemistry with cyclodextrins (CDs) using an experimental-theoretical approach combining capillary electrophoresis (CE), Nuclear Magnetic Resonance (NMR) spectroscopy and computational models. The results revealed that β-CD exhibits high selectivity over several CDs tested for the accommodation of the studied compounds. Orientation of guests in inclusion complexes was experimentally assessed by Nuclear Overhauser Effect (NOE) contacts and supported by quantum-chemical calculations. Moreover, investigation of noncovalent interactions of azopyrimidines with β-CD by CE showed that azopyrimidines with suitable structural modification can form strong complexes with high values of binding constants (over 17 000 L mol−1). For such complexes, trans-cis isomerization proceeds directly inside the β-CD cavity with azopyrimidine remaining encapsulated through its narrower primary portal. By contrast, in weakly interacting complexes, the trans isomer is released, and the cis isomer is generated outside the cavity. In subsequent re-complexation, the cis isomer is then re-captured through the wider secondary portal. Therefore, our findings point to two significantly different complexation processes depending on substitutional pattern and binding constant values of azopyrimidines; a feature which may lead to future promising applications.

АСПЕКТИ ФОРМУВАННЯ КОМПЛЕКСУ МАРКЕТИНГУ НА ПІДПРИЄМСТВАХ СФЕРИ ГОСТИННОСТІ В СУЧАСНИХ УМОВАХ

The article examines the traditional and modern understanding of the concept of marketing. The proposed author's interpretation of marketing in hospitality industry establishments based on the proposed modern features of marketing formation in hospitality enterprises, including: guest orientation, relationship building, value creation and communication. Marketing has been identified as one of the critical factors for the success of the hospitality industry as the industry is highly competitive and marketing strategies play a key role in attracting and retaining guests. The main components of the marketing complex for establishments in the hospitality industry have been studied. Practically analyzed components of the marketing mix: product (service), price, promotion, place, people, process and physical evidence. Hospitality products and services can be defined as any offering that an establishment provides to its guests, including accommodation, food and beverage, entertainment and other amenities. Pricing strategies in the hospitality industry involve pricing products and services that are competitive, profitable and attractive to guests. In the hospitality industry, effective promotion can help increase brand awareness, attract new guests and retain existing guests. By understanding the strengths and weaknesses of different channels and optimizing their distribution strategy, establishments can effectively attract large numbers of guests and ensure long-term growth and profitability. The "human" component of marketing in the hospitality industry is critical in providing exceptional quality guest service. The "process" component of marketing in the hospitality industry is characterized by the implementation of operational and service processes related to providing guests with hospitality products and services. The physical evidence of the hospitality industry covers everything from the design and layout of the hotel or restaurant to the decor and furnishings. It is substantiated that the successful application of the components of the marketing complex in the institutions of the hospitality industry is vital for creating a successful marketing strategy, solving problems and using opportunities.

Uticaj uslužne orijentacije na zadovoljstvo zaposlenih - studija slučaja "A" hoteli

Hotel business is a complex process whose primary goals are reflected in meeting the needs and wishes of guests. In order to achieve them, it is necessary for employees to develop an adequate service orientation, which would also contribute to job satisfaction. Consequently, in addition to theoretical examination of domestic and foreign scientific literature, the aim of this work is to examine the service orientation and satisfaction of guests within the first hotel chain on the territory of the Republic of Serbia. Well-known survey guidelines were used, which have also been recognized in foreign scientific literature. Based on previous research, and according to the results of this study, three factors within the service orientation of employees were singled out, while the scale of job satisfaction was expected to be one-dimensional. As part of the conclusion, some basic guidelines have been offered, which represent the backbone of the obtained statistical results.

A General Picture of Cucurbit[8]uril Host-Guest Binding.

Describing, understanding, and designing complex interaction networks within macromolecular systems remain challenging in modern chemical research. Host-guest systems, despite their relative simplicity in both the structural feature and interaction patterns, still pose problems in theoretical modeling. The barrel-shaped supramolecular container cucurbit[8]uril (CB8) shows promising functionalities in various areas, e.g., catalysis and molecular recognition. It can stably coordinate a series of structurally diverse guests with high affinities. In this work, we examine the binding of seven commonly abused drugs to the CB8 host, aiming at providing a general picture of CB8-guest binding. Extensive sampling of the configurational space of these host-guest systems is performed, and the binding pathway and interaction patterns of CB8-guest complexes are investigated. A thorough comparison of widely used fixed-charge models for drug-like molecules is presented. Iterative refitting of the atomic charges suggests significant conformation dependence of charge generation. The initial model generated at the original conformation could be inaccurate for new conformations explored during conformational search, and the newly fitted charge set improves the prediction-experiment correlation significantly. Our investigations of the configurational space of CB8-drug complexes suggest that the host-guest interactions are more complex than expected. Despite the structural simplicities of these molecules, the conformational fluctuations of the host and the guest molecules and orientations of functional groups lead to the existence of an ensemble of binding modes. The insights of the binding thermodynamics, performance of fixed-charge models, and binding patterns of the CB8-guest systems are useful for studying and elucidating the binding mechanism of other host-guest complexes.

Photochemistry using a host-guest charge transfer paradigm: DMABN as a dynamical probe of ground and excited states.

Photoexciting charge transfer (CT) transitions arising from host-guest interactions in a confined environment can efficiently yield kinetically trapped radicals. In order to predispose these photogenerated radicals for diffusion limited reactions it becomes imperative to understand the nature of the host-guest CT interactions in the ground and excited states. Here we probe the heterogeneity of guest orientations and the ensuing excited state charge transfer dynamics of an electron-rich molecular probe N,N-dimethylaminobenzonitrile (DMABN) incarcerated inside an electron deficient water-soluble cationic Pd6L412+ nanohost. Using a combination of 1H-NMR, resonance Raman spectrosocopy, and pump-probe spectroscopy we highlight the necessary challenges that need to be addressed in order to use molecular cages as photocatalytic reaction vessels.

Structure determination of terpenes by the crystalline sponge method

The crystalline sponge method was used to produce novel encapsulation complexes with the aim of structural determination of terpenes, such as geraniol-monoterpenoid, farnesol-sesquiterpenoid and β-damascone-tetraterpenoids. Along with the structure determination of the terpenoids, non-bonding CH-π and π-π interactions were identified in the host-guest complexes, which were responsible for holding the guests in the specific position with respect to the framework. In addition, the orientation of guests with respect to the framework was studied.

A Quinoline-Appended Cyclodextrin Derivative as a Highly Selective Receptor and Colorimetric Probe for Nucleotides.

SummaryThe design and development of specific recognition and sensing systems for biologically important anionic species has received growing attention in recent years, as they play significant roles in biology, pharmacy, and environmental sciences. Herein, a new supramolecular sensing probe L1 was developed for highly selective differentiation of nucleotides. L1 displayed extremely marked absorption and emission differentiation upon binding with nucleotide homologs of AMP, ADP, and ATP, due to the divergent spatial orientations of guests upon binding, which allowed for a naked-eye colorimetric differentiation for nucleotides. A differentiating mechanism was unambiguously rationalized by using various spectroscopic studies and theoretical calculations. Furthermore, we successfully demonstrated that L1 can be applied to the real-time monitoring of the enzyme-catalyzed phosphorylation/dephosphorylation processes and thus demonstrated an unprecedented visualizable strategy for selectively differentiating the structurally similar nucleotides and real-time monitoring of biological processes via fluorescent and colorimetric changes.

Orientation measurements of clay minerals by polarized attenuated total reflection infrared spectroscopy

The orientation and organization of molecular guests within the interlayer of clay minerals control the reactivity and performance of tailored organo-clay materials. Such a detailed investigation of hybrid structure on the molecular scale is usually provided by computational methods with limited experimental validation. In this study, polarized attenuated total reflection infrared spectroscopy was used to extract quantitative orientation measurements of montmorillonite particles. The validity of the evanescent electric field amplitude calculations necessary to derive the order parameter was critically evaluated to propose a methodology for determining the orientation of the normal to the clay layer relative to a reference axis, enabling comparison with the results obtained from X-ray scattering experiments and molecular dynamic simulations. Subsequently, the orientation of the interlayer water dipole and surface hydroxyls with respect to the normal of the clay layer was experimentally determined, showing good agreement with molecular simulations. This methodology may provide quantitative insights into the molecular-level description of interfacial processes between organic molecules and clay minerals.

Role of Host–Guest Charge Transfer in Cyclodextrin Complexation: A Computational Study

Charge transfer (CT) was proposed to play a role in the cyclodextrin (CD) complexation with guest molecules. To elucidate the importance of CT interactions, here we used computational methods of quantum mechanics, docking, and molecular dynamics (MD) to investigate α-CD complexes with aromatic guest molecules of nitrobenzene, carboxybenzene, benzoate, 4-nitrophenol, and 4-nitrophenolate. Considering host–guest CT in the docking has more of a chance to search reasonable guest orientations relative to α-CD matching the experiment, compared to that without CT. The CT interaction enlarges the difference in binding affinities of varied guests, as evidenced from potential of mean force (PMF) MD calculations. Energy decomposition of the total enthalpy and entropy shows the CT influence on the binding reactions in detail and indicates that there are considerable compensating effects of individual contributions from the binding partners and surrounding water. Charge transfer reduces the total dipole of α-CD by 9% ...

호텔 종사원의 직무교육이 직무만족과 고객지향성에 미치는 영향에 관한 연구

The purpose of this study is to find out how Job Training affects job satisfaction and guest orientations for hotel employees. Job Training was categorized into 4 factors while job satisfaction and guest orientation in single dimension. Hotel employees in Seoul area helped with the survey: 500 was distributed and 399 were used for this research. SPSS 18.0 program was used for the analysis and below are the results. First, among 4 factors of Job Training, trainers’ training skills and contents, training curriculum, trainees' attitudes have positive effects to job satisfaction. Second, all of 4 factors of Job Training; trainers’ training skills and contents, training curriculum, trainees' attitudes, and training center's atmosphere have positive effects to guest orientation. Third, job satisfaction has positive effects to guest orientation. Based on the study results, properly prepared Job Training have positive effects to both job satisfaction and guest orientation. Through this, hotel employees are satisfied with their job duties, this will improve service level. As the results, improved service level will satisfy guest satisfactions and have positive effects to guest orientation. Hotel trainers, therefore, need to develop proper training programs that can improve hotel employees' job capabilities and train new/existing employees routinely.

Structural Tunability Controlled by Uniaxial Strength in a Hybrid Perovskite

High-pressure studies based on neutron diffraction reveal uniaxial strength in the hybrid ABX3-type metal guanidinium formates, regardless of its symmetry across the phase transition. This interesting phenomenon is associated with the orientation of the guanidinium guest which regulates the cooperation between hydrogen bonding and octahedral tilting. This key understanding of the physical mechanism behind the phase change attests to the importance of this phenomenon in the design and development of hybrid perovskites by accomplishing befitting guest–host interactions.

An Intelligent Low-Power Displaying System withIntegrated Emergency Alerting Capability.

Integrated communication infrastructure has become a must-have facility for modern public buildings and offices. To cover this need, several commercial products exist on the market, but most of them require advanced technical skill to operate, while others require manual and time-consuming operations. This work proposes an intelligent displaying and alerting system (called SICIAD), implemented over an integrated communication infrastructure with support for wireless ePaper and iBeacon technologies to enhance displaying static and dynamic information, as well as to ease the indoor orientation of guests. A centralized display management console is implemented, as well as procedures for automatically displaying different types of notifications. An Android mobile application is developed which enables indoor user location and guidance. The system targets educational and research institutions but could also cope with public institutions such as museums and hospitals. Remote authentication is supported in research facilities through eduroam technology, access being provided by the user’s distant institution of affiliation. Secure multiple-level access to the system is provided to users, from guests to system administrators, based on locally defined policies. Functional validation and performance evaluation aspects are presented for the proposed system.

More than Smiles – Employee Empowerment Facilitating High-Quality, Consistent Services – The Wakaya Club, Fiji

Tourism and Hospitality service organisations are increasingly searching for suitable management strategies that enable the delivery of consistent-quality services, and enhanced customer satisfaction and loyalty. An approach that has gained much support in academic discourse is employee empowerment. However, questions have also been raised as to the applicability of Western-designed management concepts to multi-ethnic workforces within such developing countries as Fiji. More realistic implementation of Western management strategies is likely to be more successful if they were adapted to consider cross-cultural management and the different characteristics of national cultures. Organisations in Fiji are constantly plagued with problems related to the delivery of quality-consistent services. This study revealed that employee empowerment evolved at The Wakaya Club as an inherent part of the high-quality, luxury tourism services they offered, and was not specifically implemented. Through careful research and planning, together with a clear guest orientation and understanding of their needs and expectations, consistent, enhanced service quality was maintained at the resort. Within their planning and operational procedures and policies, cultural characteristics of their multi-ethnic employees were considered. The Wakaya Club (TWC) practices have the potential to create significant improvements if transferred to other service organisations in tourism, hospitality, and Fiji generally.

Guest Exchange through Facilitated Transport in a Seemingly Impenetrable Hydrogen-Bonded Framework.

A new inclusion compound consisting of a guanidinium 1,3,5-tri(4-sulfophenyl)benzene (G3TSPHB) host framework containing isophorone guests that surround isolated and seemingly inaccessible pockets was amenable to guest exchange with hexafluorobenzene (HFB) through a single crystal-single crystal transformation (SCSCT). Single-crystal X-ray diffraction of intermediate transformation states, from the parent compound G3TSPHB·(isophorone)3.7·(methanol)5.4 to the final state G3TSPHB·(isophorone)3.1·(HFB)2·(methanol)2, indicated a crystal symmetry change from monoclinic to hexagonal prior to full incorporation of HFB. Optical microscopy during the SCSCT revealed the formation of lamellae, which expanded and then coalesced into a single crystal when the phase transformation was complete. In situ Raman microscopy revealed changes in the orientation of isophorone guests during the transformation that suggested a pathway for HFB entry into the host cavities. The SCSCT occurs more rapidly than expected on the basis of simple diffusion, consistent with facilitated transport along the lamellae interfaces and a reduction in the length scale for guest exchange.

Guest–Host Interactions in Mixed CH4–CO2 Hydrates: Insights from Molecular Dynamics Simulations

Classical molecular dynamics simulations of mixed CH4–CO2 gas hydrates provide a thorough analysis of the energetics of both pure CH4 and CO2 hydrates and three intermediate compositions along the (CH4)1–x(CO2)x·5.75(H2O) solid solution. The energy is broken into guest–guest, guest–host, and host–host contributions. Radial distribution functions and three-dimensional density distributions provide insight into the changes in guest orientation and interactions with the host framework as a function of guest composition. Both energetic and structural analyses provide complementary information to previous experimental studies of the system. The experimentally observed isotropic orientation of CH4 molecules in both small and large cages is confirmed and the description of the anisotropic orientation of CO2 molecules in the large cage is confirmed and further enhanced. In mixed hydrates, the presence of CH4 alters the orientation of CO2, an indication that the interactions between guests, either direct (guest–gu...

The Relationship of Service Providers’ Perceptions of Service Climate to Guest Satisfaction, Return Intentions, and Firm Performance

In this article, we replicate and extend the guest–server exchange (GSX) model to include guest return intentions as a mediator between guest satisfaction and unit-level sales. With the extended model, we establish that guest return intentions are strongly connected to financial performance and are a better indicator of unit-level sales when compared with guest satisfaction as previously modeled. Furthermore, our model confirms that guest satisfaction is a statistically significant consequent of service orientation, but is best treated as an antecedent to guest return intentions, rather than unit-level sales as previously modeled. Other results consistent with existing research on the GSX showed that line-level employees’ recognition of service delivery standards being in place is strongly connected to line-level employees’ perceptions of coworker and supervisor support. The former was significantly related to line-level employee guest orientation, which was related to guest orientation. Supervisor support was not found to affect guest orientation in the model, consistent with previous tests of the GSX.

Charge Determines Guest Orientation: A Combined NMR and Molecular Dynamics Study of β-Cyclodextrins and Adamantane Derivatives.

The strong binding of the adamantyl moiety to the cavity of β-cyclodextrin makes it a common binding motif in supramolecular chemistry and a common model system. Despite the attention, there are still unresolved questions regarding the orientation of the adamantane derivatives in the inclusion complexes-do they protrude from the wide or narrow opening of the cyclodextrin hosts? A combined analysis of ROESY NMR and molecular dynamics simulations allows the conclusion that positively charged adamantane derivatives are oriented with the hydrophilic group protruding from the wider opening of the cyclodextrin, while negatively charged adamantane derivatives form two coexisting types of complexes where the hydrophilic group respectively protrudes from the wide and narrow opening. Interestingly, structural modifications of the cyclodextrin host only have a slight impact on the guest orientation.