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1.
Chem Sci ; 15(12): 4581-4589, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38516097

RESUMO

The realization of high energy is of great importance to unlock the practical potential of zinc-iodine batteries. However, significant challenges, such as low iodine loading (mostly less than 50 wt%), restricted iodine reutilization, and severe structural pulverization during cycling, compromise its intrinsic features. This study introduces an optimized, fully zincified zinc iodide loaded onto a hierarchical carbon scaffold with high active component loading and content (82 wt%) to prepare a thick cathode for enabling high-energy Zn-I2 batteries. The synergistic interactions between nitrogen heteroatoms and cobalt nanocrystals within the porous matrix not only provide forceful chemisorption to lock polyiodide intermediates but also invoke the electrocatalytic effects to manipulate efficient iodine conversion. The ZnI2 cathode could effectively alleviate continuous volumetric expansion and maximize the utilization of active species. The electrochemical examinations confirm the thickness-independent battery performance of assembled Zn-I2 cells due to the ensemble effect of composite electrodes. Accordingly, with a thickness of 300 µm and ZnI2 loading of up to 20.5 mg cm-2, the cathode delivers a specific capacity of 92 mA h gcathode-1 after 2000 cycles at 1C. Moreover, the Zn-I2 pouch cell with ZnI2 cathode has an energy density of 145 W h kgcathode-1 as well as a stable long cycle life.

2.
Health Sci Rep ; 6(11): e1730, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38028701

RESUMO

Background and Aims: Pregnancy is a stressful experience, which can affect different aspects of a woman's life. Yet, women with a supportive network of friends and family may experience lower stress and improved self-care behavior. The study aimed to investigate the relationship between perceived stress and pregnancy distress with the self-care of pregnant women, as well as the mediating role of social support. Methods: This cross-sectional study was conducted from February to May 2022 in Babol, Iran. A total of 157 pregnant women participated in the study. The participants completed five questionnaires, including a demographic and obstetric questionnaire, a Self-care questionnaire, Perceived Social support (PSS), Perceived Stress Inventory (PSI), and Pregnancy Specific Distress. Structural equation modeling was used to test the hypothesis relationships among the variables. Results: We found that Perceived stress (ß = -0.221, p = 0.012ß) and pregnancy distress (ß = -0.203, p = 0.002ß) had a negative and significant effect on the self-care of pregnant women. Also, perceived stress (ß = -0.429, p < 0.001ß) and pregnancy distress (ß = -0.381, p < 0.001ß) had a negative and significant effect on the social support of pregnant women. The results exhibited a significant specific indirect effect between pregnancy distress, perceived stress, and pregnancy self-care, with social support as the mediator: standardized indirect effect = -0.068, -0.076, respectively. Conclusion: According to the findings, social support plays a direct and mediating role in improving self-care behaviors among pregnant women. Therefore, providing strategies and measures to improve perceived social support by maternal health professionals may be expected to reduce the impact of stress on pregnant women's self-care. The implementation of policies and social interventions to improve the social support of pregnant women can be one of the applications of the findings.

3.
BMC Pregnancy Childbirth ; 23(1): 793, 2023 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-37964209

RESUMO

BACKGROUND: Psychological distress (PD) is a significant issue during pregnancy and postpartum, adversely affecting both children and mothers. This study aims to determine PD's prevalence and risk factors in a large Iranian population sample during pregnancy and postpartum. METHODS: A cross-sectional study was conducted using data from the Babol Pregnancy Mental Health Registry (located in the north of Iran) between June 2020 and March 2021. A total of 2305 women were included, with 1639 during pregnancy and 666 during postpartum. Psychological distress was assessed using the Brief Symptoms Inventory (BSI-18), and data were analyzed using independent t-tests and multiple logistic regressions. RESULTS: The prevalence of psychological distress, defined by a cut-off score of BSI ≥ 13, was 19% during pregnancy and 15% during postpartum. Multivariate logistic analysis revealed that high-risk pregnancy was the leading risk factor for psychological distress during the antenatal period (ß = 1.776, P < 0.001), as well as its three subscales: somatization (ß = 1.355, P = 0.019), anxiety symptoms (ß = 2.249, P < 0.001), and depressive symptoms (ß = 1.381, P = 0.028). Additionally, women with a gestational age < 20 weeks had a higher risk of psychological distress (ß = 1.344, P = 0.038) and the somatization subscale (ß = 1.641, P < 0.001). During the postpartum period, women residing in urban areas were at higher risk of psychological distress (ß = 1.949, P = 0.012), as well as two subscales: anxiety symptoms (ß = 1.998, P = 0.012) and depressive symptoms (ß = 1.949, P = 0.020). CONCLUSION: The high prevalence of psychological distress emphasizes detecting and treating PD during pregnancy and postpartum, particularly in women with high-risk pregnancies. This study suggests that obstetricians and midwives should implement programs to identify women experiencing psychological distress during early pregnancy through postpartum visits.


Assuntos
Depressão Pós-Parto , Angústia Psicológica , Criança , Feminino , Gravidez , Humanos , Lactente , Estudos Transversais , Saúde Mental , Irã (Geográfico)/epidemiologia , Período Pós-Parto/psicologia , Ansiedade/epidemiologia , Ansiedade/psicologia , Gravidez de Alto Risco , Depressão Pós-Parto/psicologia , Depressão/epidemiologia , Estresse Psicológico/psicologia
4.
BMC Womens Health ; 23(1): 619, 2023 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-37990232

RESUMO

BACKGROUND: Previous studies have demonstrated that excessive gestational weight gain (GWG) increases the risk of gestational diabetes mellitus (GDM). This study aimed to determine the effect of using health coaching on the prevention of GDM in overweight pregnant women. METHODS: In this quasi-experimental study, 64 eligible overweight women at 12-14 gestational weeks were randomly divided into 2 groups: the coaching group and the control group (usual care group). The intervention group received 8 weeks of the phone coaching program, which integrated GWG and physical activity to reduce the incidence of GDM. The Pregnancy Physical Activity Questionnaire (PPAQ) was used to assess physical activity during pregnancy. The occurrence of gestational diabetes was determined based on the 75-g 2-hour oral glucose tolerance test (OGTT) at 24-28 weeks of gestation. The primary outcome was the incidence of GDM, and the secondary outcomes included physical activity, GWG, and neonatal and maternal birth outcomes. RESULTS: The incidence of GDM in the control and intervention groups was 24.1% and 22.6%, respectively. The relative risk (RR) was 0.93 (95% CI, 0.37-2.34; P = 0.887). The post survey results indicated that GWG decreased more considerably in the coaching than in the control group between pre-trial (T0) and post-trial (T1), (MD; -2.49 with 95% CI, -4.38 to -0.60; P < 0.011). Moreover, the total GWG (between pre-pregnancy and birth) diminished more remarkably in the coaching than in the control group, (MD; -2.83 with 95% CI, -5.08 to -0.58; P < 0.014). However, the score of self-efficacy and concern about PPAQ Metabolic Equivalent of Task (METs) did not differ between the coaching and control groups. CONCLUSIONS: The findings and implications of this research could significantly contribute to maternal health and gestational diabetes prevention. Additional support from a midwife coach resulted in better GWG. More studies are needed to assess the impact of health coaching as a component of usual care and its long-term effect on maternal and neonatal outcomes.


Assuntos
Diabetes Gestacional , Tutoria , Recém-Nascido , Feminino , Gravidez , Humanos , Diabetes Gestacional/prevenção & controle , Sobrepeso/complicações , Sobrepeso/epidemiologia , Gestantes , Obesidade/complicações , Obesidade/prevenção & controle , Obesidade/epidemiologia , Aumento de Peso , Índice de Massa Corporal
5.
Sci Bull (Beijing) ; 68(12): 1283-1294, 2023 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-37258378

RESUMO

Metallic Zn represents as a primary choice in fabricating various aqueous Zn-ion batteries (ZIBs), however challenging issues including dendrite growth and parasitic reactions at the anode/electrolyte interface, considerably hamper its practical implementation in large-scale energy storage. Herein, we report a low-cost multifunctional ion rectifier (IRT) as an artificial intermediate to reform Zn anode, which can practically eliminate the above issues. The hydrophobic shell (polyvinylidene difluoride) can suppress Zn interfacial corrosion with an inhibition efficiency of 94.8% by repelling water molecules from the bulk electrolyte. Additionally, negatively-charged ion channels inside the zincophilic core (ultrathin vermiculite sheets) induce de-solvating redistribution effect on Zn2+ ions flux, enabling a high ions transference number (0.79) for dendrite-free Zn deposition. This leads to exceptional Zn/Zn2+ reversibility in metallic Zn with IRT stabilization. The remarkable Coulombic efficiency (99.8%, 2000 cycles) for asymmetrical batteries, and a long lifespan (1600 h) with ultrahigh cumulative capacity of 2400 mAh cm-2 for symmetrical batteries, are successfully achieved. More encouragingly, the Zn//NH4V4O10 pouch cell retains 94.3% of its original capacity after 150 cycles at 1 A g-1. We believe that this low-cost and high-efficiency tactic could pave a promising path for anode surface modification.

6.
J Comput Chem ; 44(21): 1776-1785, 2023 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-37133985

RESUMO

A nonionizing ultrafast laser pulse of 20-fs duration with a peak amplitude electric-field ±E = 200 × 10-4 a.u. was simulated. It was applied to the ethene molecule to consider its effect on the electron dynamics, both during the application of the laser pulse and for up to 100 fs after the pulse was switched off. Four laser pulse frequencies ω = 0.2692, 0.2808, 0.2830, and 0.2900 a.u. were chosen to correspond to excitation energies mid-way between the (S1 ,S2 ), (S2 ,S3 ), (S3 ,S4 ) and (S4 ,S5 ) electronic states, respectively. Scalar quantum theory of atoms in molecules (QTAIM) was used to quantify the shifts of the C1C2 bond critical points (BCPs). Depending on the frequencies ω selected, the C1C2 BCP shifts were up to 5.8 times higher after the pulse was switched off compared with a static E-field with the same magnitude. Next generation QTAIM (NG-QTAIM) was used to visualize and quantify the directional chemical character. In particular, polarization effects and bond strengths, in the form of bond-rigidity vs. bond-flexibility, were found, for some laser pulse frequencies, to increase after the laser pulse was switched off. Our analysis demonstrates that NG-QTAIM, in partnership with ultrafast laser irradiation, is useful as a tool in the emerging field of ultrafast electron dynamics, which will be essential for the design, and control of molecular electronic devices.

7.
Oman Med J ; 38(2): e480, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37113749

RESUMO

Objectives: To investigate the prevalence of psychiatric symptoms/distress and posttraumatic stress (PTS) and associated factors among inpatients with COVID-19 before discharge from the hospital. Methods: This cross-sectional study was conducted in two teaching referral hospitals in Babol, Iran from July to November 2020. The subjects were inpatients diagnosed with COVID-19 who were clinically stable. Before their discharge from the hospital, the patients completed three questionnaires: demographic data, Brief Symptom Inventory, and Primary Care Post Traumatic Stress Disorder Screen for Diagnostic and Statistical Manual-5. Results: The subjects were 477 inpatients diagnosed with COVID-19 including 40 (8.4%) admitted to intensive care units. Their average age was 60.5±17.9 years; 53.9% were female. Most had symptoms of significant psychological distress (96.0%) and PTS (8.1%) prior to discharge. A higher level of education (-0.18; standard error (SE) = 0.05; p < 0.001) was a negative predictor of psychiatric distress. The admission to intensive care units (0.86; SE = 0.08; p< 0.001) was a positive predictor of psychiatric distress. Conclusions: Most COVID-19 inpatients suffered significant psychiatric distress and PTS symptoms before discharge. Appropriate mental health crisis interventions are recommended for COVID-19 patients during hospitalization.

8.
Inj Prev ; 29(3): 272-279, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36600587

RESUMO

BACKGROUND: Risky driving behaviour including anger while driving has led to millions of global road traffic crashes, thousands of mortalities and injuries. These losses are much more in middle-income countries, such as Iran. This paper explains methods of data collection in a controlled trial study for evaluating the effect of psychosocial interventions on risky driving by using simulated and real driving. METHODS: This non-randomised controlled trial study will include 180 offender drivers. They will refer to the simulation laboratory by traffic police after their driving licences were suspended. At baseline, all participants will fill five questionnaires including demographic, Driving Anger Scale, Driving Anger Expression Scale, Spielberger's Anger and Manchester Driving Behavioural, and then they will be tested with a driving simulator. Afterwards, they will be allocated to one of three-intervention training arms (mindfulness, meta-cognition and social marketing) or a control arm without any training. Risky driving behaviours will be assessed in three follow-ups after intervention. The primary outcome of interest will be driving offences, recorded by traffic police in two time points: at 6 months and 1 year after the intervention. DISCUSSION: This study examines the effect of three interventions in reducing driving offence. The results can end in a new therapeutic training or a new legislation that should be added to current obligatory training for getting driving licence and can lead to long-term safe driving among Iranian drivers. Future research is recommended to study the cost-effectiveness of these interventions in actual driving in Iran. TRIAL REGISTRATION NUMBER: UMIN000039493.


Assuntos
Condução de Veículo , Criminosos , Humanos , Acidentes de Trânsito/prevenção & controle , Intervenção Psicossocial , Irã (Geográfico)
9.
Iran J Psychiatry ; 17(2): 187-195, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36262753

RESUMO

Objective: This study aimed to assess anxiety and depression during the COVID-19 outbreak among students aged 8 to 18 years and to determine related demographic and other related factors. Method : A descriptive and analytical cross sectional study was conducted through web-based data collection which included 348 students aged 8 to 18 years in the state of Mazandaran, Iran during the first peak of COVID-19. Demographic and Revised Children's Anxiety and Depression Scale (RCADS-P) questionnaires were used to collect the data. The statistical tests including independent sample t test, ANOVA as well as linear regression were employed. Results: The average age of the subjects was reported to be 12.2 ± 3.59 years. Age, father's occupation, following COVID-19 related news, and also nervousness related to infection were predictors of anxiety (11%). Moreover, age, mother's occupation, family communication and also the safety protocols practiced by the family were found to be predictors of depression in students (17%). A significant relationship was also found between the effect of quarantine on family communication and the anxiety and depression in students (P < 0.001). Conclusion: Demographic characteristics affect student mental health during the COVID-19 outbreak. Moreover, family preventive protocols can predict depression in students aged 8 to 18 years. Better preventive precautions encourage less anxiety and depression.

10.
Menopause ; 29(10): 1189-1195, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-36070877

RESUMO

OBJECTIVE: This study aimed to determine the effects of health coaching on reducing menopausal symptoms in postmenopausal and perimenopausal women. METHODS: This randomized controlled study was performed on 94 postmenopausal and perimenopausal women aged 45 to 55 years. The participants were randomly divided into intervention and control groups. In the intervention group, health coaching was performed in five coaching sessions biweekly (30-45 minutes each) by a midwifery coach. The primary outcome of this study was the menopausal score based on the modified Kupperman Index at 4 months after randomization. Depression (based on Zung's Self-Rating Depression Scale), physical activity (based on the International Physical Activity Questionnaire), quality of life (based on the 12-Item Short-Form Survey), smoking, alcohol intake, and anthropometric indices were also evaluated as secondary outcomes. RESULTS: There was a significant mean difference between the coaching and control groups in terms of change in the scores of menopausal symptoms from baseline (T0) to 4 months after the intervention (T1; -12.51; 95% confidence interval [CI], -10.59 to -14.42; P = 0.001). Moreover, a significant mean difference was observed between the two groups in terms of change in depression symptoms from T0 to T1 (-5.72; 95% CI, -7.61 to -3.83; P < 0.001) and in terms of quality of life (4.13; 95% CI, 2.95 to 5.31; P < 0.001). Health coaching, however, had no effects on the physical activity of the participants. CONCLUSION: Based on the present results, the coaching intervention is a suitable method to improve quality of life by reducing weight, waist circumference, body mass index, depression, and menopausal symptoms in postmenopausal and perimenopausal women. It can have important effects on the development of health promotion programs to reduce menopausal symptoms in menopause clinics.


Assuntos
Tutoria , Perimenopausa , Feminino , Humanos , Menopausa , Pós-Menopausa , Qualidade de Vida
11.
J Chem Phys ; 155(20): 204305, 2021 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-34852485

RESUMO

This study aims to investigate the phenomenon of torquoselectivity through three thermal cyclobutene ring-opening reactions (N1-N3). This research focuses on the nature of the chemical bond, electronic reorganization, predicting non-competitive or competitive reactions, and torquoselectivity preference within Quantum Theory of Atoms in Molecules (QTAIM) and stress tensor frameworks. Various theoretical analyses for these reactions, such as metallicity ξ(rb), ellipticity ε, total local energy density H(rb), stress tensor polarizability ℙσ, stress tensor eigenvalue λ3σ, and bond-path length, display differently for non-competitive and competitive reactions as well as for the conrotatory preferences either it is the transition state outward conrotatory (TSout) or transition state inward conrotatory (TSin) directions by presenting degeneracy or non-degeneracy in their results. The ellipticity profile provides the motion of the bond critical point locations due to the different substituents of cyclobutene. In agreement with experimental results, examinations demonstrated that N1 is a competitive reaction and N2-N3 are non-competitive reactions with TSout and TSin preference directions, respectively. The concordant results of QTAIM and stress tensor scalar and vectors with experimental results provide a better understanding of reaction mechanisms.

12.
World J Microbiol Biotechnol ; 36(2): 28, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32002680

RESUMO

In Saccharomyces cerevisiae, los1 encodes a nuclear tRNA exporter. Despite the non-essentiality, the deletion of los1 has been shown to extend replicative life span in yeast. Here, we characterized AfuXpot, the los1 homologue in human pathogen Aspergillus fumigatus and found that it is continuously expressed during fungal growth. Microscopic examination of an AfuXpot-GFP-expressing transformant confirmed the nuclear localization of the fusion protein. The targeted gene deletion affirmed the non-essential role of AfuXpot in hyphal growth and sporulation. However, the growth of the deletion mutant was affected by amino acid, but not glucose, deprivation. The susceptibility of the deletant strain to protein and DNA/RNA synthesis inhibitors was also altered. Using bioinformatics tools, some transcription factor binding sites were predicted in AfuXpot promoter. Expression analyses of potential AfuXpot-interacting genes showed a marked down-regulation of sfp1 and mtr10 homologues in ΔAfuXpot strain. Our data demonstrates some conserved aspects of AfuXpot as a tRNA exporter in A. fumigatus.


Assuntos
Aminoácidos/metabolismo , Aspergillus fumigatus/crescimento & desenvolvimento , Aspergillus fumigatus/genética , Proteínas Fúngicas/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , RNA Fúngico/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Aminoácidos/deficiência , Aspergillus fumigatus/metabolismo , Clonagem Molecular , DNA Fúngico/genética , DNA Fúngico/isolamento & purificação , Farmacorresistência Fúngica , Proteínas Fúngicas/genética , Deleção de Genes , Regulação Fúngica da Expressão Gênica , Glucose/metabolismo , Hifas/crescimento & desenvolvimento , Complexo de Proteínas Formadoras de Poros Nucleares/genética , Regiões Promotoras Genéticas , RNA Fúngico/isolamento & purificação , RNA de Transferência/genética , RNA de Transferência/isolamento & purificação , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
13.
Phys Chem Chem Phys ; 22(2): 864-877, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31844863

RESUMO

In this investigation we set out to understand the origins of non-nuclear attractors (NNAs) found for neutral lithium clusters Lim (m = 2-5) on the QTAIM molecular graph but not on the Ehrenfest force F(r) molecular graph. Therefore, we pursued the stress tensor σ(r) without using the dependency on the QTAIM partitioning, since previously σ(r) was only calculated within the QTAIM partitioning, to see if any indication of NNA character can be determined. Because the stress tensor σ(r) lacks an associated scalar- or vector-field as is the case for QTAIM and the Ehrenfest F(r) partitioning schemes respectively, a stress tensor σ(r) partitioning scheme cannot be constructed. Therefore, to overcome this difficulty we use next generation QTAIM, constructed from the most preferred directions of electronic charge density accumulation, to calculate the stress tensor σ(r) 3-D bond-paths on the Ehrenfest force F(r) molecular graph. Using next generation 3-D bond-paths within the Ehrenfest force F(r) partitioning, we can classify the degree of NNA character in the absence of NNAs. A much higher degree of NNA character is found to be present for the stress tensor σ(r) 3-D bond-paths than for the corresponding QTAIM or Ehrenfest force F(r) 3-D bond-paths. The stabilizing effect of the NNA is demonstrated by undertaking Li2 bond-path compression and stretching distortions sufficient to cause the annihilation of the NNA. The compression and stretching distortions also lead to a large increase in the 3-D bond-path asymmetry and persistent bond-path torsion respectively.

14.
J Comput Chem ; 41(9): 913-921, 2020 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-31880358

RESUMO

The effect of a varying, directional E x , E y , and E z electric field on the ethene molecule was investigated using next-generation quantum theory of atoms in molecules (QTAIM). Despite using low E-field strengths that are within the realm of experiment and do not measurably alter the molecular geometry, significant changes to the QTAIM properties were observed. Using conventional QTAIM, the shifting of the C─C and C─H bond critical points (BCPs) demonstrates polarization through an interchange in the size of the atoms involved in a bond, since a BCP is located on the boundary between a pair of bonded atoms. Next-generation QTAIM, however, demonstrates the polarization effect more directly with a change in morphology of the 3-D envelope around the BCP. Modest increases of ≈ 2% in the ellipticity ε of the BCP were uncovered when the C─C bond was aligned parallel or anti-parallel to the applied E x -field. Significant asymmetries were found in the response of the next-generation QTAIM 3-D paths of the C─H bonds to the applied E-field. When the E-field coincided with the C─C bond, the BCP moved in response and was accompanied by the envelope constructed from 3-D next-generation paths. The response displayed a polarization effect that increased with increasing magnitude of the E x -field parallel and anti-parallel to the C─C bond. Our analysis demonstrates that next-generation QTAIM is a useful tool for understanding the response of molecules to E-fields, for example, for the screening of molecular wires for the design of molecular electronic devices. © 2019 Wiley Periodicals, Inc.

15.
J Phys Chem A ; 123(38): 8254-8264, 2019 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-31487180

RESUMO

In this investigation, we considered both the scalar and 3-D vector-based measures of bonding using next generation quantum theory of atoms in molecules (QTAIM), constructed from the preferred direction of electronic charge density accumulation, to better understand the photochemical reaction associated with of the formation of benzvalene from benzene. The formation of benzvalene from benzene resulted in two additional C-C bonds forming compared with the benzene. The creation of the additional C-C bonds was explained in terms of an increasing the favorability of the reaction process by maximizing the bonding density. The topological instability of the benzvalene structure was determined using the scalar and vector-based measures to explain the short chemical half-life of benzvalene in terms of the competition between the formation of unstable new C-C bonding that also destabilizes nearest neighbor C-C bonds. The explosive character of benzvalene is indicated by the unusual tendency of the C-C bonds to rupture as easily as weak bonding. The topological instability of the short strong C-C bonds was explained by the existence of measures from conventional and next generation QTAIM that previously have only been observed in weak interactions; such measures included twisted 3-D bonding descriptors.

16.
J Comput Chem ; 40(21): 1881-1891, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-30980547

RESUMO

The effect of an electric field on a recently proposed molecular switch based on a quinone analogue was investigated using next-generation quantum theory of atoms in molecules (QTAIM) methodology. The reversal of a homogenous external electric field was demonstrated to improve the "OFF" functioning of the switch. This was achieved by destabilization of the H atom participating in the tautomerization process along the hydrogen bond that defines the switch. The "ON" functioning of the switch, from the position of the tautomerization barrier, is also improved by the reversal of the homogenous external electric field: this result was previously inaccessible. The "ON" and "OFF" functioning of the switch was visualized in terms of the response of the most preferred directions of motion of the electronic charge density to the applied external field. All measures from QTAIM and the stress tensor provide consistent results for the factors affecting the "ON" and "OFF" switch performance. Our analysis therefore demonstrates use for future design of molecular electronic devices. © 2019 Wiley Periodicals, Inc.

17.
Phys Chem Chem Phys ; 20(38): 24695-24707, 2018 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-30225484

RESUMO

In this investigation we explore the function and existence of the non-nuclear attractor (NNA) for a series of small charged lithium clusters Limq (m = 2-5, q = ±1) using QTAIM and the Ehrenfest force F(r) partitioning schemes. The NNAs were found to be present in all of the Limq (m = 2-5, q = ±1) clusters for QTAIM, in contrast none were found for F(r). We discovered that the anionic and cationic lithium dimers are limiting cases for minimal and maximal impact of the NNA related to the relative sparseness of total charge density ρ(r) distributions respectively. Evidence is found that the NNA in the anionic dimer is in the process of being annihilated by two neighboring BCPs. We provide a measure of the size of the NNA and find for Limq (m = 2-5, q = ±1) that larger NNAs correlate with increased Li-Li separations. The NNA was determined to be a persistent feature by varying the Li separations for the cationic and anionic dimers. Very large Li separations failed to induce an NNA in the F(r) anionic dimer and therefore we conclude that F(r) is unable to detect NNAs. The metallicity ξ(rb) was also used to measure the sparseness of the distribution of ρ(r) and significant metallic character, on the basis of ξ(rb) > 1, was present for QTAIM but not for F(r), providing further evidence that F(r) cannot detect NNAs. Advantages of the use of Ehrenfest force F(r) partitioning scheme are discussed that include the design of nano-devices through tuning of the Ehrenfest potential VF(b) by the application of external forces such as a constant electric or strain field.

18.
Phys Chem Chem Phys ; 19(38): 26423-26434, 2017 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-28944790

RESUMO

A new QTAIM interpretation of the Ramachandran plot is formulated from the most and least facile eigenvectors of the second-derivative matrix of the electron density with a set of 29 magainin-2 peptide conformers. The presence of QTAIM eigenvectors associated with the most and least preferred directions of electronic charge density explained the role of hydrogen bonding, HH contacts and the glycine amino acid monomer in peptide folding. The highest degree of occupation of the QTAIM interpreted Ramachandran plot was found for the glycine amino acid monomer compared with the remaining backbone peptide bonds. The mobility of the QTAIM eigenvectors of the glycine amino acid monomer was higher than for the other amino acids and was comparable to that of the hydrogen bonding, explaining the flexibility of the magainin-2 backbone. We experimented with a variety of hybrid QTAIM-Ramachandran plots to highlight and explain why the glycine amino acid monomer largely occupies the 'forbidden' region on the Ramachandran plot. In addition, the new hybrid QTAIM-Ramachandran plots contained recognizable regions that can be associated with concepts familiar from the conventional Ramachandran plot whilst retaining the character of the QTAIM most and least preferred regions.

19.
J Phys Chem A ; 121(25): 4778-4792, 2017 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-28586210

RESUMO

A quantum theory of atoms in molecules (QTAIM) and stress tensor analysis was applied to analyze intramolecular interactions influencing the photoisomerization dynamics of a light-driven rotary molecular motor. For selected nonadiabatic molecular dynamics trajectories characterized by markedly different S1 state lifetimes, the electron densities were obtained using the ensemble density functional theory method. The analysis revealed that torsional motion of the molecular motor blades from the Franck-Condon point to the S1 energy minimum and the S1/S0 conical intersection is controlled by two factors: greater numbers of intramolecular bonds before the hop-time and unusually strongly coupled bonds between the atoms of the rotor and the stator blades. This results in the effective stalling of the progress along the torsional path for an extended period of time. This finding suggests a possibility of chemical tuning of the speed of photoisomerization of molecular motors and related molecular switches by reshaping their molecular backbones to decrease or increase the degree of coupling and numbers of intramolecular bond critical points as revealed by the QTAIM/stress tensor analysis of the electron density. Additionally, the stress tensor scalar and vector analysis was found to provide new methods to follow the trajectories, and from this, new insight was gained into the behavior of the S1 state in the vicinity of the conical intersection.

20.
Pancreas ; 40(8): 1271-5, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21975434

RESUMO

OBJECTIVE: To evaluate the effect of chemoembolization on pancreatic cancer liver metastases. METHOD: Thirty-two patients with pancreatic cancer liver metastases retrospectively underwent chemoembolization (4- to 8-week intervals). Size-based evaluation (response evaluation criteria in solid tumors [RECIST]) and survival indexes were assessed overall and for sex and number of lesions. RESULTS: Of the patients, 71.87% showed stable disease, 9.37% partial response (PR) and 18.75% progressive disease (PD). Survival rate for 1, 3, and 5 years from first TACE was 60%, 25%, and 11%, respectively. Median survival time was 16 months and for stable disease group was 20 months. Progression-free survival for 6 months and 1, 3, and 5 years was 84%, 57.3%, 20%, and 10%, respectively. There was significant difference between men and women in response. Survival rates for 1 and 5 years for the men were 80% and 14% and for the women were 47% and 0%. There was no significant difference between oligonodular liver lesion (n < 5) and multinodular (n > 5) groups. Survival rates for 1 and 5 years for oligonodular were 84% and 14%, and for multinodular was 50% and 0%. CONCLUSION: Repetitive TACE resulted in a relevant response for the control of liver metastases of pancreatic cancer with respectable median survival time. Interestingly, the number of lesions, statistically, was not an effective factor.


Assuntos
Quimioembolização Terapêutica/métodos , Neoplasias Hepáticas/terapia , Neoplasias Pancreáticas/terapia , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Feminino , Humanos , Infusões Intra-Arteriais , Estimativa de Kaplan-Meier , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-Idade , Compostos Organoplatínicos/administração & dosagem , Neoplasias Pancreáticas/patologia , Piridinas/administração & dosagem , Estudos Retrospectivos , Resultado do Tratamento , Carga Tumoral/efeitos dos fármacos , Gencitabina
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