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1.
Emerg Infect Dis ; 30(6): 1285-1288, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38703022

RESUMEN

We isolated novel reassortant avian influenza A(H5N6) viruses containing genes from clade 2.3.4.4b H5N1 virus and low pathogenicity avian influenza viruses in carcasses of whooper swans and bean geese in South Korea during December 2023. Neuraminidase gene was from a clade 2.3.4.4b H5N6 virus infecting poultry and humans in China.


Asunto(s)
Animales Salvajes , Aves , Virus de la Influenza A , Gripe Aviar , Filogenia , Animales , Gripe Aviar/virología , Gripe Aviar/epidemiología , República de Corea/epidemiología , Animales Salvajes/virología , Virus de la Influenza A/genética , Virus de la Influenza A/clasificación , Aves/virología , Virus Reordenados/genética , Historia del Siglo XXI , Humanos , Neuraminidasa/genética
2.
Emerg Infect Dis ; 30(2): 299-309, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38215495

RESUMEN

During October 2022-March 2023, highly pathogenic avian influenza (HPAI) A(H5N1) clade 2.3.4.4b virus caused outbreaks in South Korea, including 174 cases in wild birds. To understand the origin and role of wild birds in the evolution and spread of HPAI viruses, we sequenced 113 HPAI isolates from wild birds and performed phylogenetic analysis. We identified 16 different genotypes, indicating extensive genetic reassortment with viruses in wild birds. Phylodynamic analysis showed that the viruses were most likely introduced to the southern Gyeonggi-do/northern Chungcheongnam-do area through whooper swans (Cygnus cygnus) and spread southward. Cross-species transmission occurred between various wild bird species, including waterfowl and raptors, resulting in the persistence of HPAI in wild bird populations and further geographic spread as these birds migrated throughout South Korea. Enhanced genomic surveillance was an integral part of the HPAI outbreak response, aiding in timely understanding of the origin, evolution, and spread of the virus.


Asunto(s)
Subtipo H5N1 del Virus de la Influenza A , Gripe Aviar , Gripe Humana , Animales , Humanos , Subtipo H5N1 del Virus de la Influenza A/genética , Filogenia , Animales Salvajes , Aves , Gripe Humana/epidemiología , Patos , República de Corea/epidemiología
3.
Opt Express ; 31(4): 7032-7046, 2023 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-36823948

RESUMEN

A method, which can accurately measure carbon emission and gas temperature simultaneously in real-time from a laser-induced breakdown spectrum (LIBS) via machine learning, is proposed in this study. In typical, peak intensity ratios had been used to map species concentrations prior to plasma formation, after removing the broadband continuum of the spectrum; however, the dependence of these peak intensity ratios on the concentration changes with the change in gas density. Therefore, considering the fact that the strength and shape of this broadband continuum is a function of the gas density for a given optical setup, we attempted to collect a spectrum by shortening the time delay after the laser fire, such that the spectrum can contain some of the broadband continuum. Since the analytical quantification of this broadband continuum is not trivial, we employed a machine learning approach to acquire a model that simultaneously predicts the gas temperature and CO2 concentration. The predictive performance of the model trained with spectra that contain the broadband continuum was much better than that without it; the gradient-weighted regression activation mapping (Grad-RAM) analysis revealed that the model utilizes the broadband spectrum for temperature prediction and correction of changes in peak intensity due to temperature changes in the concentration prediction process.

4.
Angew Chem Int Ed Engl ; 61(41): e202205348, 2022 10 10.
Artículo en Inglés | MEDLINE | ID: mdl-35792701

RESUMEN

We report the density functional theory (DFT) guided discovery of ethynyl-triazolyl-phosphinates (ETPs) as a new class of electrophilic warheads for cysteine selective bioconjugation. By using CuI -catalysed azide alkyne cycloaddition (CuAAC) in aqueous buffer, we were able to access a variety of functional electrophilic building blocks, including proteins, from diethynyl-phosphinate. ETP-reagents were used to obtain fluorescent peptide-conjugates for receptor labelling on live cells and a stable and a biologically active antibody-drug-conjugate. Moreover, we were able to incorporate ETP-electrophiles into an azide-containing ubiquitin under native conditions and demonstrate their potential in protein-protein conjugation. Finally, we showcase the excellent cysteine-selectivity of this new class of electrophile in mass spectrometry based, proteome-wide cysteine profiling, underscoring the applicability in homogeneous bioconjugation strategies to connect two complex biomolecules.


Asunto(s)
Azidas , Cisteína , Alquinos/química , Azidas/química , Cisteína/química , Péptidos , Proteoma , Ubiquitinas
5.
Sensors (Basel) ; 21(4)2021 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-33572357

RESUMEN

Shear wave velocity and small-strain shear modulus are widely used as the mechanical properties of soil. The objective of this study is to develop a new shear wave monitoring system using a pair of piezoelectric ring benders (RBs) and to evaluate the suitability of RB in compacted soils compared with the bender element and ultrasonic transducer. The RB is a multilayered piezoelectric actuator, which can generate shear waves without disturbing soils. For five compacted soil specimens, the shear waves are monitored by using three different piezoelectric transducers. Results of time-domain response show that the output signals measured from the RB vary according to the water content of the specimen and the frequency of the input signal. Except at the water content of 9.3%, the difference in the resonant frequencies between the three transducers is not significant. The shear wave velocities for the RB are slightly greater than those for the other transducers. For the RB, the exponential relationship between the shear wave velocity and dry unit weight is better established compared with that of the other transducers. The newly proposed piezoelectric transducer RB may be useful for the evaluation of the shear wave velocity and small-strain shear modulus of compacted soils.

6.
Sensors (Basel) ; 21(9)2021 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-33925195

RESUMEN

Dynamic resistance, which can be used to express strength in the unit of stress and improve the reliability of the dynamic cone penetration test (DCPT), has been estimated by numerous methods. This study aims to compare different dynamic resistance estimation methods by using an instrumented dynamic cone penetrometer (IDCP). DCPTs are conducted using a standard dynamic cone penetrometer (DCP) and IDCP in the laboratory and field. Dynamic responses are obtained from the strain gauges and an accelerometer installed at the cone tip of the IDCP. The test results show that dynamic resistance is more efficient in distinguishing profiles than the dynamic cone penetration index. Among the methods to estimate the dynamic resistance at the cone tip, the force-velocity integration method and force integration method are more related to the conventional dynamic resistance considering the potential energy of the hammer than the force squared integration method. Additionally, the dynamic resistance estimated for a longer time period is more reliable, particularly for small driving rod lengths. Regarding the limitation of the dynamic response from an accelerometer in a previous study, the force-based dynamic resistance estimated for a longer time period can be used as the most reliable approach for further soil strength characterization.


Asunto(s)
Suelo , Reproducibilidad de los Resultados
7.
J Musculoskelet Neuronal Interact ; 20(4): 541-548, 2020 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-33265082

RESUMEN

OBJECTIVE: The purpose of this study was to investigate the difference in back extensor muscle endurance before and after kinesiology tape application to all back stabilizer muscles and to the erector spinae alone. METHODS: We assessed 32 adults (16 men and 16 women), randomly divided into two groups. In the erector spinae taping (EST) group, kinesiology tape was applied only to the erector spinae, and in the total muscle taping (TMT) group, kinesiology tape was applied to the erector spinae, latissimus dorsi, lower trapezius, internal oblique abdominis, and external oblique abdominis. RESULTS: Both groups showed significant difference in terms of back extensor muscle endurance after kinesiology tape application (p<0.05). Between-group comparison revealed that the TMT group had more back extensor muscle endurance than the EST group (p<0.05) after kinesiology tape application. CONCLUSIONS: These findings indicate that, to improve back extensor muscle endurance, kinesiology tape should be applied to all back stabilizer muscles, rather than to the erector spinae muscles alone.


Asunto(s)
Cinta Atlética , Músculos de la Espalda/fisiología , Fatiga Muscular/fisiología , Resistencia Física/fisiología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Equilibrio Postural/fisiología
8.
Sensors (Basel) ; 20(23)2020 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-33260463

RESUMEN

The objective of this study was to develop a horizontally elongated time domain reflectometry (HETDR) system to evaluate the water content in nonuniformly wetted soils. The HETDR probe consists of three rods of stainless steel and a cuboid head: A center electrode and two outer electrodes are connected to the inner and outer conductors of a coaxial cable, respectively. An acrylic container divided into several segments was used to prepare nonuniformly wetted soils with different water contents for a series of model tests. The HETDR probe was placed horizontally at the middle height of each soil specimen, while a conventional time domain reflectometry (TDR) probe was applied vertically on the surface of the specimen. The experimental results show that as the soil water content (SWC) at a segment increases, the average amplitude decreases and the duration increases. The estimated SWC increases with the measured SWC, and especially, the difference between actual segment length and the segment length estimated from the HETDR probes is significant under dry conditions. This study demonstrates that HETDR may be a promising field-testing method for evaluating the average water content in nonuniformly wetted soils.

9.
Sensors (Basel) ; 20(21)2020 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-33114329

RESUMEN

The objective of this study is to develop a new vibration-free excavation method based on vermiculite expansion for rock cracking and to evaluate the performance of the heating system via elastic wave monitoring. Natural vermiculites expand rapidly in volume when heated above 800 °C. MgO powder is used to evenly transmit the surface temperature of a heater rod, which can attain high temperatures rapidly, to the vermiculites. The insertion direction of the heater rod greatly affects the expansion pressure. Three cuboid rock specimens are prepared and equipped with the heating system at different hole-to-face distances. Crack propagation is monitored by a pair of disk-shaped piezoelectric transducers. For short hole-to-face distances, the wave velocity and maximum amplitude rapidly decrease after certain time. For the greatest hole-to-face distance, the shear wave velocity remains constant during the test, while the maximum amplitude decreases after a certain time. The time taken for the velocity and amplitude of the shear waves to decrease reasonably corresponded to that taken for detectable crack propagation to occur on the surface of the rock specimen. The proposed method and materials may be useful from the viewpoints of rapid expansion, economy, and crack control.

10.
Int J Mol Sci ; 21(11)2020 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-32532135

RESUMEN

Transmissible spongiform encephalopathies (TSEs) have been reported in a wide range of species. However, TSE infection in natural cases has never been reported in dogs. Previous studies have reported that polymorphisms of the prion protein gene (PRNP) have a direct impact on the susceptibility of TSE. However, studies on polymorphisms of the canine PRNP gene are very rare in dogs. We examined the genotype, allele, and haplotype frequencies of canine PRNP in 204 dogs using direct sequencing and analyzed linkage disequilibrium (LD) using Haploview version 4.2. In addition, to evaluate the impact of nonsynonymous polymorphisms on the function of prion protein (PrP), we carried out in silico analysis using PolyPhen-2, PROVEAN, and PANTHER. Furthermore, we analyzed the structure of PrP and hydrogen bonds according to alleles of nonsynonymous single nucleotide polymorphisms (SNPs) using the Swiss-Pdb Viewer program. Finally, we predicted the impact of the polymorphisms on the aggregation propensity of dog PrP using AMYCO. We identified a total of eight polymorphisms, including five novel SNPs and one insertion/deletion polymorphism, and found strong LDs and six major haplotypes among eight polymorphisms. In addition, we identified significantly different distribution of haplotypes among eight dog breeds, however, the kinds of identified polymorphisms were different among each dog breed. We predicted that p.64_71del HGGGWGQP, Asp182Gly, and Asp182Glu polymorphisms can impact the function and/or structure of dog PrP. Furthermore, the number of hydrogen bonds of dog PrP with the Glu182 and Gly182 alleles were predicted to be less than those with the Asp182 allele. Finally, Asp163Glu and Asp182Gly showed more aggregation propensity than wild-type dog PrP. These results suggest that nonsynonymous SNPs, Asp182Glu and Asp182Gly, can influence the stability of dog PrP and confer the possibility of TSE infection in dogs.


Asunto(s)
Perros/genética , Polimorfismo de Nucleótido Simple , Enfermedades por Prión/genética , Proteínas Priónicas/genética , Animales , Resistencia a la Enfermedad/genética , Enfermedades de los Perros/genética , Frecuencia de los Genes , Haplotipos , Enlace de Hidrógeno , Desequilibrio de Ligamiento , Enfermedades por Prión/veterinaria , Proteínas Priónicas/química , Secuencias Repetidas en Tándem
11.
Opt Express ; 22(3): 2289-98, 2014 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-24663521

RESUMEN

Low insertion-loss single-layer and bilayer metamaterial filters in terahertz (THz) frequency regime were demonstrated on top of low cost flexible Scotch tape by utilizing pattern transfer method. The transmittance of the flexible 51-µm-thick Scotch tape was found out to be higher than 0.85 in the range of 0.2 to 3 THz, which is excellent for the substrate materials for THz applications. Free standing filters exhibited record low insertion loss of 0.6 dB and band rejection ratio as high as 30 dB. The resonance reflection characteristics of the bilayer filters were maintained when they were attached on top of curved PET bottle or metallic surfaces, providing promising application in THz identifications.

12.
J Nanosci Nanotechnol ; 14(7): 5228-31, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24758008

RESUMEN

We have investigated THz radiation characteristics along different directions, either reflective or along lateral by using InAs-based heterostructures. Firstly, we demonstrate the phase shift with InAs layer thickness, revealing the change of dominant THz wave generation mechanism along both directions. Along the lateral direction, the time-domain signals in thin InAs epilayers showed an abrupt phase and amplitude change at certain time delays which suggest the interference between two rays at the photoconductive switch. This behavior was further substantiated by the multiple cavity modes in Fourier-transformed spectra and by the amplitude variation with excitation spot displacement.

13.
PLoS One ; 19(6): e0305771, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38917136

RESUMEN

Research on prognostic factors for good outcomes in out-of-hospital cardiac arrest (OHCA) survivors is lacking. We assessed whether normal levels of normal neuron-specific enolase (NSE) value would be useful for predicting good neurological outcomes in comatose OHCA survivors treated with targeted temperature management (TTM). This registry-based observational study with consecutive adult (≥18 years) OHCA survivors with TTM who underwent NSE measurement 48 hours after cardiac arrest was conducted from October 2015 to November 2022. Normal NSE values defined as the upper limit of the normal range by the manufacturer (NSE <16.3 µg/L) and guideline-suggested (NSE < 60 µg/L) were examined for good neurologic outcomes, defined as Cerebral Performance Categories ≤2, at 6 months post-survival. Among 226 OHCA survivors with TTM, 200 patients who underwent NSE measurement were enrolled. The manufacturer-suggested normal NSE values (<16.3 µg/L) had a specificity of 99.17% for good neurological outcomes with a very low sensitivity of 12.66%. NSE <60 µg/L predicted good outcomes with a sensitivity of 87.34% and specificity of 72.73%. However, excluding 14 poor-outcome patients who died from multi-organ dysfunction excluding hypoxic brain injury, the sensitivity and specificity of normal NSE values were 12.66% and 99.07% of NSE < 16.3 µg/L, and 87.34% and 82.24% of NSE < 60 µg/L. The manufacturer-suggested normal NSE had high specificity with low sensitivity, but the guideline-suggested normal NSE value had a comparatively low specificity for good outcome prediction in OHCA survivors. Our data demonstrate normal NSE levels can be useful as a tool for multimodal appropriation of good outcome prediction.


Asunto(s)
Coma , Paro Cardíaco Extrahospitalario , Fosfopiruvato Hidratasa , Humanos , Fosfopiruvato Hidratasa/sangre , Paro Cardíaco Extrahospitalario/mortalidad , Paro Cardíaco Extrahospitalario/terapia , Paro Cardíaco Extrahospitalario/complicaciones , Masculino , Femenino , Persona de Mediana Edad , Coma/etiología , Anciano , Sobrevivientes , Pronóstico , Hipotermia Inducida , Adulto
14.
Osong Public Health Res Perspect ; 15(3): 260-264, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38988029

RESUMEN

BACKGROUND: We analyzed the correlation between the infectivity and transmissibility of the severe acute respiratory syndrome coronavirus 2 Omicron sublineages BA.1, BA. 2, BA.4, and BA.5. METHODS: We assessed viral replication kinetics and infectivity at the cellular level. Nasopharyngeal and oropharyngeal specimens were obtained from patients with coronavirus disease 2019, confirmed using whole-genome sequencing to be caused by the Omicron sublineages BA.1, BA.2, BA.4, or BA.5. These specimens were used to infect Vero E6 cells, derived from monkey kidneys, for the purpose of viral isolation. Viral stocks were then passaged in Vero E6 cells at a multiplicity of infection of 0.01, and culture supernatants were harvested at 12-hour intervals for 72 hours. To evaluate viral replication kinetics, we determined the cycle threshold values of the supernatants using real-time reverse transcription polymerase chain reaction and converted these values to genome copy numbers. RESULTS: The viral load was comparable between BA.2, BA.4, and BA.5, whereas BA.1 exhibited a lower value. The peak infectious load of BA.4 was approximately 3 times lower than that of BA.2 and BA.5, while the peak load of BA.2 and BA.5 was about 7 times higher than that of BA.1. Notably, BA.1 demonstrated the lowest infectivity over the entire study period. CONCLUSION: Our results suggest that the global BA.5 wave may have been amplified by the higher viral replication and infectivity of BA.5 compared to other Omicron sublineages. These analyses could support the rapid assessment of the impact of novel variants on case incidence.

15.
One Health ; 18: 100719, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38585666

RESUMEN

The winter of 2020-2021 in South Korea witnessed severe outbreaks of Highly Pathogenic Avian Influenza (HPAI) viruses, specifically multiple genotypes of the H5N8 subtype. These outbreaks prompted an extensive investigation into the genetic characteristics and evolutionary dynamics of these viruses. Under the auspices of the National Institute of Wildlife Disease Control and Prevention (NIWDC), we conducted a nationwide surveillance program, collecting 7588 specimens from diverse wild bird habitats. Influenza A viruses were isolated at a rate of 5.0%, with HPAI H5N8 viruses accounting for 38.5% of isolates, predominantly found in wild bird carcasses (97.3%). Genetic analysis revealed the emergence of novel HPAI genotypes due to genetic reassortment events. G1 and G2 viruses were separately introduced into Korea, with G1 viruses displaying dynamic behavior, resulting in diverse sub-genotypes (G1-1 to G1-5) and mainly isolated from clinical specimens. Conversely, the G2 virus, introduced later, became the dominant strain consistently isolated mainly from bird carcasses (88.9%). These findings underscore the emergence of numerous novel HPAI genotypes shaped by multiple reassortment events in high-density wintering grounds of migratory birds. These sites act as hotspots for genetic exchanges, significantly influencing avian ecology, including resident bird species, and contributing to HPAI H5N8 evolution. The genetic diversity and ongoing evolution of these viruses highlight the need for vigilant surveillance and adaptive control measures. Recognizing the potential spillover to human populations, a One Health approach is essential to mitigate the evolving threats posed by avian influenza.

16.
Bioprocess Biosyst Eng ; 36(12): 1939-45, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23689758

RESUMEN

In this study, we proposed a new method for estimating biokinetic parameters in phenol degradation kinetics. The new method relies on the new formulation of q-S relation where degradation rate q is calculated from the changes of substrate concentration S for each time segment during the course of entire degradation, while in the conventional method q is obtained from the slope of the straight line that is given as substrate concentration changes with time in a semi-logarithmic scale. Thus, this new method provided more data points than the conventional method. The q-S relations obtained from the new method and the conventional method were fitted with three inhibitory kinetic models of Haldane, Yano and Edwards. Simulation of degradation profile with each kinetic model and comparison with the observed profile revealed that the new method offered a better prediction with Edwards model as the best inhibitory model.


Asunto(s)
Fenoles/metabolismo , Cinética , Especificidad por Sustrato
17.
Environ Technol ; 34(17-20): 2757-64, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24527639

RESUMEN

In this study, the deposition and transport of Pseudomonas aeruginosa on sandy porous materials have been investigated under static and dynamic flow conditions. For the static experiments, both equilibrium and kinetic batch tests were performed at a 1:3 and 3:1 soil:solution ratio. The batch data were analysed to quantify the deposition parameters under static conditions. Column tests were performed for dynamic flow experiments with KCl solution and bacteria suspended in (1) deionized water, (2) mineral salt medium (MSM) and (3) surfactant + MSM. The equilibrium distribution coefficient (K(d)) was larger at a 1:3 (2.43 mL g(-1)) than that at a 3:1 (0.28 mL g(-1)) soil:solution ratio. Kinetic batch experiments showed that the reversible deposition rate coefficient (k(att)) and the release rate coefficient (k(det)) at a soil:solution ratio of 3:1 were larger than those at a 1:3 ratio. Column experiments showed that an increase in ionic strength resulted in a decrease in peak concentration of bacteria, mass recovery and tailing of the bacterial breakthrough curve (BTC) and that the presence of surfactant enhanced the movement of bacteria through quartz sand, giving increased mass recovery and tailing. Deposition parameters under dynamic condition were determined by fitting BTCs to four different transport models, (1) kinetic reversible, (2) two-site, (3) kinetic irreversible and (4) kinetic reversible and irreversible models. Among these models, Model 4 was more suitable than the others since it includes the irreversible sorption term directly related to the mass loss of bacteria observed in the column experiment. Applicability of the parameters obtained from the batch experiments to simulate the column breakthrough data is evaluated.


Asunto(s)
Pseudomonas aeruginosa/citología , Microbiología del Suelo , Adhesión Bacteriana , Cinética , Modelos Biológicos , Porosidad , Cloruro de Potasio/química , Dióxido de Silicio/química , Tensoactivos/química , Agua/química
18.
Korean J Physiol Pharmacol ; 17(1): 9-13, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23440944

RESUMEN

The aim of the present study was to examine the effect of micellar systems on the absorption of beta-lapachone (b-lap) through different intestinal segments using a single-pass rat intestinal perfusion technique. B-lap was solubilized in mixed micelles composed of phosphatidylcholine and sodium deoxycholate, and in sodium lauryl sulfate (SLS)-based conventional micelles. Both mixed micelles and SLS micelles improved the in situ permeability of b-lap in all intestinal segments tested although the mixed micellar formulation was more effective in increasing the intestinal absorption of b-lap. The permeability of b-lap was greatest in the large intestinal segments. Compared with SLS micelles, the effective permeability coefficient values measured with mixed micelles were 5- to 23-fold higher depending on the intestinal segment. Our data suggest that b-lap should be delivered to the large intestine using a mixed micellar system for improved absorption.

19.
Front Vet Sci ; 10: 1229369, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37808111

RESUMEN

Transmissible spongiform encephalopathies (TSEs) have been reported in a broad spectrum of hosts. The genetic polymorphisms and characteristics of the prion protein (PRNP) gene have a vital impact on the development of TSEs. Notably, natural TSE infection cases have never been reported in rabbits, and genetic variations of the leporine PRNP gene have not been investigated to date. To identify leporine PRNP gene polymorphism, we performed amplicon sequencing in 203 rabbits. We report a novel single nucleotide polymorphism on the leporine PRNP gene. In addition, we performed a comparative analysis of amino acid sequences of prion protein (PrP) across several hosts using ClustalW2. Furthermore, we evaluated the effect of changes of unique leporine PrP amino acids with those conserved among various species using Swiss-Pdb Viewer. Interestingly, we found seven unique leporine amino acids, and the change of unique leporine amino acids with those conserved among other species, including S175N, Q221K, Q221R, A226Y, A230G, and A230S, was predicted to reduce hydrogen bonds in leporine PrP.

20.
J Phys Chem Lett ; 14(13): 3329-3334, 2023 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-36989527

RESUMEN

We employed the chemical potential equalization principle to demonstrate that fractional electrons are involved in the electro-inductive effect as well as the vibrational Stark effect. By the chemical potential model, we were able to deduce that the frontier molecular orbitals of immobilized molecules can provide valuable insight into these effects. To further understand and quantify these findings, we introduced fractional charge density functional theory (FC-DFT), a canonical ensemble approach for open systems. This method allows for the calculation of electronic energies, nuclear gradients, and the Hessian matrix of fractional electronic systems. To correct the spurious delocalization error commonly found in approximate density functionals for small systems, we imposed the Perdew-Parr-Levy-Balduz (PPLB) condition through linear interpolation of two adjacent integer points (LI-FC-DFT). Although this approach is relatively simple in terms of molecular modeling, the results obtained through LI-FC-DFT calculations predict the same trend seen in experimental reactivity and the frequency change of immobilized molecules.

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