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1.
Appl Psychophysiol Biofeedback ; 49(2): 241-259, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38502516

RESUMEN

COVID-19 exacerbated burnout and mental health concerns among the healthcare workforce. Due to high work stress, demanding schedules made attuned eating behaviors a particularly challenging aspect of self-care for healthcare workers. This study aimed to examine the feasibility and acceptability of a heart rate variability biofeedback (HRVB) mobile app for improving well-being among healthcare workers reporting elevated disordered eating during COVID-19. We conducted a mixed methods pre-mid-post single-arm pilot feasibility trial (ClinicalTrials.gov NCT04921228). Deductive content analysis of participants' commentary generated qualitative themes. Linear mixed models were used to examine changes in pre- mid- to post-assessment scores on well-being outcomes. We consented 28 healthcare workers (25/89% female; 23/82% Non-Hispanic White; 22/79% nurses) to use and evaluate an HRVB mobile app. Of these, 25/89% fully enrolled by attending the app and device training; 23/82% were engaged in all elements of the protocol. Thirteen (52%) completed at least 10 min of HRVB on two-thirds or more study days. Most participants (18/75%) reported being likely or extremely likely to continue HRVB. Common barriers to engagement were busy schedules, fatigue, and technology difficulties. However, participants felt that HRVB helped them relax and connect better to their body's signals and experiences. Results suggested preliminary evidence of efficacy for improving interoceptive sensibility, mindful self-care, body appreciation, intuitive eating, stress, resilience, and disordered eating. HRVB has potential as a low-cost adjunct tool for enhancing well-being in healthcare workers through positively connecting to the body, especially during times of increased stress when attuned eating behavior becomes difficult to uphold.


Asunto(s)
Biorretroalimentación Psicológica , COVID-19 , Estudios de Factibilidad , Personal de Salud , Frecuencia Cardíaca , Aplicaciones Móviles , Autocuidado , Humanos , COVID-19/psicología , Femenino , Proyectos Piloto , Biorretroalimentación Psicológica/métodos , Masculino , Frecuencia Cardíaca/fisiología , Adulto , Personal de Salud/psicología , Persona de Mediana Edad , Trastornos de Alimentación y de la Ingestión de Alimentos/terapia , Agotamiento Profesional
2.
Artículo en Inglés | MEDLINE | ID: mdl-37552232

Asunto(s)
Tutoría , Humanos , Mentores
3.
J Nurs Manag ; 29(8): 2329-2342, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34182609

RESUMEN

AIM: The purpose of this review was to examine resilience among healthcare workers during the coronavirus-disease-2019 (COVID-19) pandemic. BACKGROUND: The COVID-19 pandemic has caused an unprecedented strain on healthcare workers internationally. Rising infection rates, inadequate personal protective equipment, and the lack of availability of hospital beds has resulted in further deterioration of the already-fragile mental health of healthcare workers. Resilient workers have lower rates of burnout and improved patient outcomes. EVALUATION: PubMed and the Cumulative Index to Nursing and Allied Health Literature databases were searched using the terms resilience, nurse and COVID-19 to identify studies on resilience during the COVID-19 pandemic. Results were organized by outcome measures for comparison. KEY ISSUES: Resilience scores among frontline healthcare workers worldwide during the COVID-19 pandemic in the studies reviewed were overall found to be in the moderate range. Data from the United States showed a decrease in nurse resilience, whereas participants from China had increased resilience compared with pre-pandemic levels. CONCLUSIONS: Building resilience in nurses and other healthcare workers can serve as a protective factor against negative outcomes related to the job, including burnout, anxiety and depression, and can improve patient outcomes. IMPLICATIONS FOR NURSING MANAGEMENT: Strategies for building resilience in healthcare workers are discussed.


Asunto(s)
Agotamiento Profesional , COVID-19 , Agotamiento Profesional/epidemiología , Personal de Salud , Humanos , Pandemias/prevención & control , SARS-CoV-2
4.
Body Image ; 37: 162-171, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33676305

RESUMEN

Disordered eating symptoms remain a largely unidentified and unsupported area in perinatal healthcare, particularly as they pertain to women without diagnosed eating disorders. In an Australian prospective cohort study, women aged 18-48, completed questionnaires between: 18-24 weeks gestation (n = 249, T1), 30-32 weeks gestation (n = 151, T2) and 8-10 weeks postpartum (n = 124, T3), measuring disordered eating symptoms, psychosocial factors (attitudes to pregnancy or motherhood, self-compassion, relationship satisfaction and perinatal social support) and mental health factors (depressive or anxiety symptoms). Multilevel linear models examined predictive associations between psychosocial factors at T1 and the change in disordered eating symptoms from T1 to T2 and from T1 to T3, in addition to the moderating effects of pre-pregnancy BMI and pregnancy depressive or anxiety symptoms. Whilst restraint and shape concerns decreased from T1 to T2, restraint, shape and weight concerns increased from T1 to T3. Psychosocial factors at T1 were able to predict the change in some disordered eating symptoms. Moreover, when pre-pregnancy BMI or pregnancy depressive or anxiety symptoms were elevated, the impact of psychosocial factors on disordered eating increased. The findings of this study provide a more complex understanding of disordered eating across the perinatal period, with implications for future interventions and research design.


Asunto(s)
Imagen Corporal/psicología , Trastornos de Alimentación y de la Ingestión de Alimentos/psicología , Periodo Posparto/psicología , Mujeres Embarazadas/psicología , Adolescente , Adulto , Australia , Femenino , Humanos , Persona de Mediana Edad , Embarazo , Estudios Prospectivos , Psicología , Factores de Riesgo , Encuestas y Cuestionarios , Adulto Joven
5.
Appetite ; 156: 104862, 2021 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-32905822

RESUMEN

The postpartum period has been identified as high-risk period for the increase of disordered eating. This study examined the psychosocial factors-attitudes to motherhood, self-compassion and relationship satisfaction- and mental health factors-depressive and anxiety symptoms-associated with this increase. One hundred and fourteen women completed online questionnaires about their eating behaviours between: 18-24 weeks gestation (T1), 30-32 weeks gestation (T2) and 8-10 weeks postpartum (T3). A cluster analysis examined the change of disordered eating from T2 to T3. Multinomial logistic regressions examined which demographic, psychosocial and mental health factors were associated with disordered eating cluster groups, as individual factors and as a combined model of predictors at T1, T2 and T3. Four cluster groups were identified: 'lower disordered eating', 'increasing risk', 'sub-clinical' and 'clinical'. All psychosocial and mental health predictors were individually associated with a risk group, when compared to the lower disordered eating group. However, when combined, only multiparity and higher depressive symptoms were associated with the sub-clinical group. Multiparity, higher pre-pregnancy body mass index and lower self-compassion were associated with the increasing risk group. This study introduces self-compassion as a psychosocial factor worthy of further investigation and application in the field of perinatal disordered eating, with promising avenues for antenatal intervention.


Asunto(s)
Trastornos de Alimentación y de la Ingestión de Alimentos , Salud Mental , Ansiedad , Femenino , Humanos , Parto , Periodo Posparto , Embarazo , Factores de Riesgo , Encuestas y Cuestionarios
6.
Int J Eat Disord ; 53(6): 873-882, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32199037

RESUMEN

OBJECTIVE: The impact of disordered eating extends beyond women with a diagnosed eating disorder. Scarce research to date has investigated disordered eating in a general perinatal population, including the complex interplay between psychosocial factors, mental health symptoms, and disordered eating at numerous pregnancy periods. Specifically, maternal attitudes and relationship satisfaction are psychosocial factors that have been identified as a gap in the literature. METHOD: Pregnant women completed an online questionnaire between 18 and 24 weeks gestation (T1, n = 258) and again between 30 and 32 weeks gestation (T2, n = 159). Structural equation modeling was used to test an interrelated model of psychosocial factors-attitudes to pregnancy, attitudes to motherhood, and relationship satisfaction-and disordered eating, mediated by either depressive or anxiety symptoms. Invariance testing examined whether model weights differed between primiparous and multiparous women at each time point. RESULTS: While at T1 and T2, there were significant direct associations between psychosocial factors and disordered eating, only at T2 were the associations between psychosocial factors and disordered eating mediated by depressive and anxiety symptoms. Furthermore, at T2, multiparous women were at greater risk of an association between maladaptive attitudes to pregnancy and motherhood, depressive symptoms, and disordered eating. DISCUSSION: The present study highlights the need to investigate the relationships between psychosocial factors and disordered eating, while accounting for the unique antenatal needs of women during different pregnancy periods and across differing parity. The mediating effect of depressive and anxiety symptoms have implications for future research and clinical care.


Asunto(s)
Trastornos de Alimentación y de la Ingestión de Alimentos/psicología , Salud Mental/normas , Mujeres Embarazadas/psicología , Psicología/métodos , Adolescente , Adulto , Estudios de Cohortes , Femenino , Humanos , Embarazo , Estudios Prospectivos , Factores de Riesgo , Encuestas y Cuestionarios , Adulto Joven
7.
Eur Eat Disord Rev ; 27(5): 462-480, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-30997724

RESUMEN

OBJECTIVE: This paper systematically reviews the literature to date on the relationship between disordered eating and mental health, psychological and social factors during pregnancy and the post-partum period, as well as the direction of associations. METHODS: Peer reviewed articles were sourced from seven databases: PsycINFO, CINAHL, Psychology and Behavioural Sciences Collection, Academic Search Complete, Scopus (MEDLINE), Web of Science, and Proquest. A quality review and best evidence synthesis was conducted. RESULTS: The final review included 11 prospective cohort and 14 cross sectional/retrospective studies. According to a synthesis of findings, a strong level of evidence supports an association between disordered eating during pregnancy and depressive and anxiety symptoms during pregnancy. There was also a limited level of evidence for the association between disordered eating and obsessive-compulsive symptoms during pregnancy and between disordered eating and depressive symptoms during the post-partum period. No directions of associations could be determined. CONCLUSIONS: On the basis of initial findings, it is recommended that depressive and anxiety symptoms be monitored in conjunction with any disordered eating concerns during perinatal care. Given the significance of the childbearing years to the health and well-being of both mother and infant, further prospective cohort studies in this area are necessitated.


Asunto(s)
Trastornos de Alimentación y de la Ingestión de Alimentos/psicología , Periodo Periparto , Ansiedad/psicología , Depresión/psicología , Femenino , Humanos , Embarazo , Mujeres Embarazadas/psicología , Factores de Riesgo
8.
J Biomech ; 80: 79-87, 2018 10 26.
Artículo en Inglés | MEDLINE | ID: mdl-30217557

RESUMEN

The objective of this study was to investigate the effects of doxycycline, a broad-spectrum MMP inhibitor, on cage activity and exercised supraspinatus tendon and muscle using a Sprague-Dawley rat model of non-injurious exercise. Because exercise may alter muscle and tendon MMP activity and matrix turnover, we hypothesized that doxycycline would abolish the beneficial adaptations found with exercise but have no effect on cage activity muscle and tendon properties. Rats were divided into acute or chronic exercise (EX) or cage activity (CA) groups, and half of the rats received doxycycline orally. Animals in acute EX groups were euthanized 24 h after a single bout of exercise (10 m/min, 1 h) on a flat treadmill. Animals in chronic EX groups walked on a flat treadmill and were euthanized at 2 or 8 week time points. Assays included supraspinatus tendon mechanics and histology and muscle fiber morphologic and type analysis. Doxycycline improved tendon mechanical properties and collagen organization in chronic cage activity groups, which was not consistently evident in exercised groups. Combined with exercise, doxycycline decreased average muscle fiber cross-sectional area. Results of this study suggest that administration of doxycycline at pharmaceutical doses induces beneficial supraspinatus tendon adaptations without negatively affecting the muscle in cage activity animals, supporting the use of doxycycline to combat degenerative processes associated with underuse; however, when combined with exercise, doxycycline does not consistently produce the same beneficial adaptations in rat supraspinatus tendons and reduces muscle fiber cross-sectional area, suggesting that doxycycline is not advantageous when combined with activity.


Asunto(s)
Antibacterianos/farmacología , Doxiciclina/farmacología , Fibras Musculares Esqueléticas/efectos de los fármacos , Tendones/efectos de los fármacos , Adaptación Fisiológica , Animales , Fenómenos Biomecánicos , Colágeno/fisiología , Masculino , Fibras Musculares Esqueléticas/fisiología , Condicionamiento Físico Animal/fisiología , Ratas Sprague-Dawley , Manguito de los Rotadores/efectos de los fármacos , Manguito de los Rotadores/fisiología , Tendones/fisiología
9.
J Appl Physiol (1985) ; 123(4): 757-763, 2017 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-28663377

RESUMEN

The objective of this study was to identify acute responses and chronic adaptations of supraspinatus tendon to noninjurious exercise. We hypothesized that chronic exercise (EX) increases tendon mechanical properties, and a single exercise bout increases matrix metalloproteinase (MMP) activity acutely. Rats were divided into acute or chronic EX or cage activity groups. Animals in acute EX groups were euthanized, 3, 12, 24, 48, or 72 h upon completion of a single bout of exercise (10 m/min, 1 h) on a flat treadmill. Animals in chronic EX groups walked on a flat treadmill for 3 days or 1, 2, or 8 wk. Tendon histology, MMP activity, and mechanics were measured. A single bout of exercise trended toward reducing tendon mechanical properties, but 2 or 8 wk of chronic EX increased tendon mechanics. Cell density was not affected. Cells became rounder with chronic EX. All tendons were highly organized. MMP activity decreased after a single bout of exercise and returned to baseline by 72 h. MMP activity decreased after 8 wk of chronic EX. Decreased MMP activity may indicate an anabolic instead of catabolic response in contrast to injury. Results suggest that mild, acute decreases in MMP activity and tendon mechanics following a single exercise bout lead to enhanced tendon mechanical adaptations with repeated exercise bouts. This study defines acute and chronic changes of MMP activity, mechanical properties, and histology of the rat supraspinatus tendon in response to beneficial exercise and proposes a mechanism by which acute responses translate to chronic adaptations.NEW & NOTEWORTHY The line between beneficial exercise and overuse has not been elucidated. This study defines the acute and chronic temporal response to exercise of supraspinatus tendon in an in vivo model. We found that decreased matrix metalloproteinase activity and tendon mechanics after a single bout of exercise are followed by beneficial chronic adaptations of the tendon with repeated bouts. How the acute responses to exercise lead to chronic adaptations may distinguish beneficial exercise from overuse.


Asunto(s)
Metaloproteinasas de la Matriz/metabolismo , Condicionamiento Físico Animal , Manguito de los Rotadores/fisiología , Tendones/fisiología , Adaptación Fisiológica , Animales , Masculino , Ratas , Ratas Sprague-Dawley
10.
Matern Child Nutr ; 13(1)2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-26725347

RESUMEN

Perinatal depression is a debilitating disorder experienced during pregnancy and/or the first year post-partum. Recently, maternal dietary intake during pregnancy has emerged as a possible area of intervention for the prevention of mental disorders in women and their offspring. However, the relationship between antenatal diet quality and perinatal depressive symptoms remains poorly understood. The current study explored the predictive role of antenatal diet quality for antenatal and post-natal depressive symptoms. Pregnant women (n = 167) were recruited between February 2010 and December 2011. Women completed the Edinburgh Postnatal Depression Scale at time 1 [T1, mean weeks gestation = 16.70, standard deviation (SD) = 0.91], time 2 (T2, mean weeks gestation = 32.89, SD = 0.89) and time 3 (T3, mean weeks post-partum = 13.51, SD = 1.97) and a food frequency questionnaire at T1 and T2. Diet quality was determined by extracting dietary patterns via principal components analysis. Two dietary patterns were identified: 'healthy' (including fruit, vegetables, fish and whole grains) and 'unhealthy' (including sweets, refined grains, high-energy drinks and fast foods). Associations between dietary patterns and depressive symptoms were investigated by path analyses. While both 'healthy' and 'unhealthy' path models showed good fit, only one significant association consistent with study hypotheses was found, an 'unhealthy' diet was associated with increased depressive symptoms at 32 weeks gestation. Given that this association was cross-sectional, it was not possible to make any firm conclusions about the predictive nature of either dietary patterns or depressive symptoms. Dietary intervention studies or larger prospective studies are therefore recommended.


Asunto(s)
Depresión Posparto/prevención & control , Dieta Saludable , Periodo Posparto , Atención Prenatal , Adolescente , Adulto , Animales , Estudios Transversales , Femenino , Peces , Calidad de los Alimentos , Frutas , Humanos , Estilo de Vida , Evaluación Nutricional , Embarazo , Estudios Prospectivos , Factores Socioeconómicos , Encuestas y Cuestionarios , Verduras , Granos Enteros , Adulto Joven
11.
Am J Sports Med ; 44(9): 2237-45, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27281275

RESUMEN

BACKGROUND: Previous studies have shown that ibuprofen is detrimental to tissue healing after acute injury; however, the effects of ibuprofen when combined with noninjurious exercise are debated. HYPOTHESIS: Administration of ibuprofen to rats undergoing a noninjurious treadmill exercise protocol will abolish the beneficial adaptations found with exercise but will have no effect on sedentary muscle and tendon properties. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 167 male Sprague-Dawley rats were divided into exercise or cage activity (sedentary) groups and acute (a single bout of exercise followed by 24 hours of rest) and chronic (2 or 8 weeks of repeated exercise) response times. Half of the rats were administered ibuprofen to investigate the effects of this drug over time when combined with different activity levels (exercise and sedentary). Supraspinatus tendons were used for mechanical testing and histologic assessment (organization, cell shape, cellularity), and supraspinatus muscles were used for morphologic (fiber cross-sectional area, centrally nucleated fibers) and fiber type analysis. RESULTS: Chronic intake of ibuprofen did not impair supraspinatus tendon organization or mechanical adaptations (stiffness, modulus, maximum load, maximum stress, dynamic modulus, or viscoelastic properties) to exercise. Tendon mechanical properties were not diminished and in some instances increased with ibuprofen. In contrast, total supraspinatus muscle fiber cross-sectional area decreased with ibuprofen at chronic response times, and some fiber type-specific changes were detected. CONCLUSION: Chronic administration of ibuprofen does not impair supraspinatus tendon mechanical properties in a rat model of exercise but does decrease supraspinatus muscle fiber cross-sectional area. This fundamental study adds to the growing literature on the effects of ibuprofen on musculoskeletal tissues and provides a solid foundation on which future work can build. CLINICAL RELEVANCE: The study findings suggest that ibuprofen does not detrimentally affect regulation of supraspinatus tendon adaptations to exercise but does decrease muscle growth. Individuals should be advised on the risk of decreased muscle hypertrophy when consuming ibuprofen.


Asunto(s)
Adaptación Fisiológica , Ibuprofeno/toxicidad , Condicionamiento Físico Animal , Manguito de los Rotadores/patología , Animales , Fenómenos Biomecánicos , Modelos Animales de Enfermedad , Masculino , Fibras Musculares Esqueléticas , Ratas , Ratas Sprague-Dawley , Tendones/patología
12.
Appetite ; 91: 41-7, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25814192

RESUMEN

BACKGROUND: While maternal nutrition during pregnancy is known to play a critical role in the health of both mother and offspring, the magnitude of this association has only recently been realized. Novel, epigenetic data suggest that maternal dietary intake has permanent phenotypic consequences for offspring, highlighting the potency of antenatal diet. To date, the relationship between poor antenatal diet and maternal mental health specifically, remains poorly understood. Therefore, we aimed to systematically review evidence that has examined associations between antenatal diet quality and the experience of depressive, anxiety and stress symptoms during the perinatal period. METHODS: A search for peer-reviewed papers was conducted using Medline Complete, PsycINFO, CINAHL, Academic Search Premiere and Psychology and Behavioral Science Collection. RESULTS: Nine studies (cohort = 4, cross-sectional = 5) published between 2005 and 2013 were eligible for inclusion in this review. A synthesis of findings revealed positive associations between poor quality and unhealthy diets and antenatal depressive and stress symptoms. Healthy diets were inversely associated with antenatal depressive and anxiety symptoms. Postnatal depressive symptoms demonstrated inconsistent results. CONCLUSIONS: Given the paucity of research examining diet quality and mental health in women during the perinatal period, further sufficiently powered studies are urgently required to examine this association.


Asunto(s)
Ansiedad/etiología , Depresión/etiología , Dieta/efectos adversos , Fenómenos Fisiologicos Nutricionales Maternos , Estrés Psicológico/etiología , Ansiedad/prevención & control , Depresión/prevención & control , Depresión Posparto/etiología , Depresión Posparto/prevención & control , Femenino , Humanos , Política Nutricional , Cooperación del Paciente , Embarazo , Estrés Psicológico/prevención & control
13.
Biochemistry ; 54(1): 83-95, 2015 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-25347386

RESUMEN

Symmetric and asymmetric crystal structures of the apo and transition state analogue forms, respectively, of the dimeric rabbit muscle creatine kinase have invoked an "induced fit" explanation for asymmetry between the two subunits and their active sites. However, previously reported thiol reactivity studies at the dual active-site cysteine 283 residues suggest a more latent asymmetry between the two subunits. The role of that highly conserved active-site cysteine has also not been clearly determined. In this work, the S-H vibrations of Cys283 were observed in the unmodified MM isoform enzyme via Raman scattering, and then one and both Cys283 residues in the same dimeric enzyme were modified to covalently attach a cyano group that reports on the active-site environment via its infrared CN stretching absorption band while maintaining the catalytic activity of the enzyme. Unmodified and Cys283-modified enzymes were investigated in the apo and transition state analogue forms of the enzyme. The narrow and invariant S-H vibrational bands report a homogeneous environment for the unmodified active-site cysteines, indicating that their thiols are hydrogen bonded to the same H-bond acceptor in the presence and absence of the substrate. The S-H peak persists at all physiologically relevant pH's, indicating that Cys283 is protonated at all pH's relevant to enzymatic activity. Molecular dynamics simulations identify the S-H hydrogen bond acceptor as a single, long-resident water molecule and suggest that the role of the conserved yet catalytically unnecessary thiol may be to dynamically rigidify that part of the active site through specific H-bonding to water. The asymmetric and broad CN stretching bands from the CN-modified Cys283 suggest an asymmetric structure in the apo form of the enzyme in which there is a dynamic exchange between spectral subpopulations associated with water-exposed and water-excluded probe environments. Molecular dynamics simulations indicate a homogeneous orientation of the SCN probe group in the active site and thus rule out a local conformational explanation at the residue level for the multipopulation CN stretching bands. The homogeneous simulated SCN orientation suggests strongly that a more global asymmetry between the two subunits is the cause of the CN probe's broad and asymmetric infrared line shape. Together, these spectral observations localized at the active-site cysteines indicate an intrinsic, dynamic asymmetry between the two subunits that exists already in the apo form of the dimeric creatine kinase enzyme, rather than being induced by the substrate. Biochemical and methodological consequences of these conclusions are considered.


Asunto(s)
Forma MM de la Creatina-Quinasa/química , Forma MM de la Creatina-Quinasa/fisiología , Compuestos de Sulfhidrilo/química , Compuestos de Sulfhidrilo/fisiología , Animales , Dominio Catalítico/fisiología , Cristalografía por Rayos X/métodos , Estructura Secundaria de Proteína , Conejos , Vibración
14.
J Phys Chem B ; 116(3): 1172-9, 2012 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-22176031

RESUMEN

Covalently bound azido groups are found in many commercially available biomolecular precursors and substrates, and the NNN asymmetric stretching band of these groups is a strong infrared absorber that appears in a spectral region clear of other signals. In order to evaluate comprehensively the solvatochromism of the asymmetric azido NNN stretching band for site-specific use in biomolecular contexts, infrared spectra of the model compounds 5-azido,1-pentanoic acid and 3-(p-azidophenyl),1-propanoic acid were acquired in a large variety of nonpolar, polar, and hydrogen-bond-donating solvents, as well as mixed aqueous-organic solvents. Spectra in pure solvents indicated that the aliphatic NNN stretching frequency maximum does not depend on solvent polarity, while the aromatic NNN frequency displays a weak but nonzero sensitivity to polarity. In both cases, the NNN frequency exhibits a blue-shift in H-bond-donating solvents, but the frequency in water is higher than in any other H-bond-donating solvent including solvents that are stronger H-bond donors. In nonfluorinated H-bond donor solvents, the frequency blue shift scales with the density of H-bond donors. This sensitivity to the presence of water was further explored in several mixed solvent environments, with the conclusion that this vibrational mode is a highly specific sensor of hydration, even in environments containing other H-bond donors like amides and alcohols, due to the very high local density of H-bond donors in water. The relatively uncomplicated (compared to nitriles, for example), water-specific response of this vibrational mode should lead to its adoption as a site-specific probe of hydration in many different possible systems in which the presence and role of molecular water is of primary interest.


Asunto(s)
Azidas/química , Enlace de Hidrógeno , Agua/química , Estructura Molecular , Solventes/química , Espectrofotometría Infrarroja/métodos
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