Nonlinear optical (NLO) materials have spanned a large area of science and technology owning to their potential applications in optoelectronics. The invention of the first Ruby laser has sparked a fresh interest in the area of nonlinear optics. The computational designing and experimental synthesis of organic and inorganic NLO materials with higher order nonlinearities come into vogue in the field of materials science. To date, several strategies including metal ligand framework, push pull mechanism, diradical character, and so on have been devised to enhance the NLO response of materials. In addition, introduction of diffuse excess electrons is an efficient approach to design noncentrosymmetric materials for nonlinear optics. The current review highlights a systematic array of different computational studies (covering the last decade of intensive research work) for the theoretical designing of NLO materials. In the present review, theoretical designing from the simplest NLO material to the complex alkali, alkaline earth, transition, and superalkali doped nanomaterials is summarized. The emergence of excess electrons strategy has played a pivotal role in enhancing the NLO properties especially hyperpolarizabilities. We expect that this review will provide a better understanding of the NLO responses of nanoclusters, paving the way for the advancement of hi-tech NLO materials to meet the real challenges in optoelectronics.
Enantiomers
have the same physical properties but different chemical
properties due to the difference in the orientation of groups in space
and thus Chiral discrimination is quite necessary, as an enantiomer
of drug can have lethal effects. In this study, we used the CC2 cage
for chiral discrimination of amino acids using density functional
theory. The results indicated the physisorption of amino acids in
the central cavity of the cage. Among the four selected amino acids,
proline showed maximum interactions with the cage and maximum chiral
discrimination energy is also observed in the case of proline that
is 2.78 kcal/mol. Quantum theory of atoms in molecules and noncovalent
interaction index analyses showed that the S enantiomer in each case
has maximum interactions. The charge transfer between the analyte
and surface is further studied through natural bond orbital analysis.
It showed sensitivity of cage for both enantiomers, but a more pronounced
effect is seen for S enantiomers. In frontier molecular orbital analysis,
the least EH‑L gap is observed in the case of R
proline with a maximum charge transfer of −0.24 e–. Electron density difference analysis is carried out to analyze
the pattern of the charge distribution. The partial density of state
analysis is computed to understand the contribution of each enantiomer
in overall density of the complexes. Our results show that S-CC2 porous
organic cages have a good ability to differentiate between two enantiomers.
S-CC2 porous organic cages efficiently differentiated the S enantiomer
from the R enantiomers of selected amino acids.
Cervical vertigo is a phrase used to describe to-and-fro vertigo and unsteadiness of gait caused by neck lesions. Cervicogenic dizziness is caused by cervical spine involvement. Cervical vertigo is caused by a variety of etiologies and processes. Objective: The study was to find Prevalence of Cervicogenic Vertigo Among Patients with Cervical Spondylosis. Methods: This study included 78 individuals who had a confirmed diagnosis of cervical spondylosis. Data was obtained from several hospitals in Lahore using a standardized vertigo questionnaire from all participants after clearance from the university ethics council and IRB UOL. Data was collected using a convenient sampling strategy. Results: Total of 78 people were selected in study. There were 45 men and 33 women among them. In this study, 65 people reported experiencing lightheadedness when dizzy, while 13 persons reported not experiencing lightheadedness when dizzy. In this study, 65 people reported experiencing blacking out when dizzy, whereas 13 persons reported not experiencing blacking out when dizzy. Conclusion: According to the findings of this investigation, cervicogenic vertigo is prevalent in senior individuals with cervical spondylosis.
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