Associations Between Primary Residence and Mental Health in Global Marginalized Populations.

Scholars suggest that marginalized people in non-urban areas experience higher distress levels and fewer psychosocial resources than in urban areas. Researchers have yet to test whether precise proximity to urban centers is associated with mental health for marginalized populations. We recruited 1733 people who reported living in 45 different countries. Participants entered their home locations and completed measures of anxiety, depression, social support, and resilience. Regression and thematic analyses were used to determine what role distance from legislative and urban centers may play in mental health when marginalized people were disaggregated. Greater distance from legislative center predicted higher anxiety and resilience. Greater distance from urban center also predicted more resilience. Thematic analyses yielded five categories (e.g., safety, connection) that further illustrated the impact of geographic location on health. Implications for community mental health are discussed including the need to better understand and further expand resilience in rural areas.

Complication rate among people with diabetes at low risk of foot ulceration in Fife, UK: an analysis of routinely collected data.

AIMS: To estimate the rate at which people with diabetes and a low risk of foot ulceration change diabetic foot ulceration risk status over time, and to estimate the rate of ulceration, amputation and death among this population. METHODS: We conducted an observational study of 10 421 people with diabetes attending foot screening in an outpatient setting in NHS Fife, UK, using routinely collected data from a national diabetes register, NHS SCI Diabetes. We estimated the proportion of people who changed risk status and the cumulative incidence of ulceration, amputation and death, respectively, among people with diabetes at low risk of diabetic foot ulceration at 2-year follow-up. RESULTS: At 2-year follow-up, 5.1% (95% CI 4.7, 5.6) of people with diabetes classified as low risk at their first visit had progressed to moderate risk. The cumulative incidence of ulceration, amputation and death was 0.4% (95% CI 0.3, 0.6), 0.1% (95% CI 0.1, 0.2) and 3.4% (95% CI 3.1, 3.8), respectively. CONCLUSIONS: At 2-year follow-up, 5% of people at low risk of diabetic foot ulceration changed clinical risk status and <1% of people experienced foot ulceration or amputation. These findings provide information which will help to inform the current debate regarding optimal foot screening intervals.

Sulfotransferase 1A3/4 copy number variation is associated with neurodegenerative disease.

The cytosolic aryl sulfotransferase genes SULT1A3 and SULT1A4 are located on chromosome 16p11.2 in a region of chromosomal instability. SULT1A3/4 are important enzymes in the metabolism of catecholamines linked to neurodegenerative diseases such as Parkinson's and Alzheimer's. In the present study, copy number variation of the SULT1A3/4 genes in healthy individuals, as well as a cohort of Parkinson's disease and Alzheimer's disease patients was examined. In all subjects, SULT1A3/4 copy number varied from 1 to 10. In Alzheimer's disease patients, there was a significantly lower copy number compared to controls, and a positive correlation between copy number and age of disease onset. By contrast, there were no differences in Parkinson's disease patients. However, when early-onset Parkinson's disease was evaluated separately, there appeared to be an association with gene copy number and risk. The current study shows that these neurodegenerative diseases may be related to SULT1A3/4 copy number.

Communication training interventions for family and professional carers of people living with dementia: a systematic review of effectiveness, acceptability and conceptual basis.

OBJECTIVES: To update previous reviews and provide a more detailed overview of the effectiveness, acceptability and conceptual basis of communication training-interventions for carers of people living with dementia. METHOD: We searched CINAHL Plus, MEDLINE and PsycINFO using a specific search and extraction protocol, and PRISMA guidelines. Two authors conducted searches and extracted studies that reported effectiveness, efficacy or acceptability data regarding a communication training-intervention for carers of people living with dementia. Risk of bias was assessed using the Cochrane Collaboration guidelines. Quality of qualitative studies was also systematically assessed. RESULTS: Searches identified 450 studies (after de-duplication). Thirty-eight studies were identified for inclusion in the review. Twenty-two studies focused on professional carers; 16 studies focused mainly on family carers. Training-interventions were found to improve communication and knowledge. Overall training-interventions were not found to significantly improve behaviour that challenges and caregiver burden. Acceptability levels were high overall, but satisfaction ratings were found to be higher for family carers than professional carers. Although many interventions were not supported by a clear conceptual framework, person-centred care was the most common framework described. CONCLUSION: This review indicated that training-interventions were effective in improving carer knowledge and communication skills. Effective interventions involved active participation by carers and were generally skills based (including practicing skills and discussion). However, improvements to quality of life and psychological wellbeing of carers and people living with dementia may require more targeted interventions.

Associations of intention to undertake physical activity among community dwelling British South Asian adults aged 60 years and over: a cross-sectional study.

OBJECTIVE: High prevalence of sedentary behaviour is seen in most immigrant groups in Western countries, particularly in those from the Indian subcontinent. The primary objective of this study was to determine the sociocognitive associations with intention to undertake physical activity (PA) among separate groups of Indian, Pakistani and Bangladeshi older adults aged ≥60 years in the North West of England, UK. STUDY DESIGN: Cross-sectional survey METHODS: Using a cross-sectional survey, informed by the Theory of Planned Behaviour (TPB), 138 of 964 South Asian (SA) older adults completed a mailed questionnaire that assessed self-reported PA and TPB variables. RESULTS: Associations were seen in beliefs about PA and the amount of PA undertaken (rho = 0.18, P = 0.04). Attitude was correlated with intention (rho = 0.29, P = 0.01) and amount of PA undertaken (rho = 0.21, P = 0.02). Subjective norm was correlated with intention to undertake PA (rho = 0.21, P = 0.02). Between-group differences were seen between (1) Indian and Pakistani group's in subjective norm; (2) all ethnicities in intention to undertake PA; and (3) in the amount and attitude to undertaking PA between men and women. Comorbidity was associated with beliefs about PA uptake. CONCLUSIONS: Subgroup differences between Indian, Pakistani and Bangladeshi older adults in subjective norm and intention to undertaking PA highlight the importance of tailoring interventions to accommodate for subgroup differences when developing culturally appropriate PA interventions aimed at increasing uptake and adherence.

A systematic review of interventions to increase physical activity among South Asian adults.

OBJECTIVES: To identify interventions aimed at increasing physical activity (PA) levels among South Asian (SA) adults and identify the specific changes in the content and delivery mode of interventions designed to increase PA levels among SA people aged ≥18 years. DESIGN: A systematic review of quantitative studies. DATA SYNTHESIS: Extracted data were synthesized using a narrative approach. DATA SOURCES: ASSIA, CINHAL, EMBASE, Medline, SPORTDiscus and PsychINFO were searched. Included articles met the following criteria: (1) population: community-dwelling SA adults aged ≥18 years and (2) outcome: reporting determinants of PA, exercise, or a combination of the two, measured objectively or using self-report. The search was restricted to articles published in the English language up to 31 January 2017. RESULTS: Fifteen trials/programmes (16 articles) met the review criteria. The findings show that involving the target community in developing culturally appropriate interventions appears to be important in their acceptability, delivery and uptake. Using community-based participation in intervention planning, evaluation and research appears to produce culturally and linguistically tailored interventions that address core values, attitudes, beliefs and norms, and encourage participation in PA. Furthermore, the use of community health workers and underpinning the interventions with a psychological theory show promise in increasing PA uptake. CONCLUSIONS: This systematic review suggests that making cultural adaptations to PA interventions shows promise, but the evidence base presented is not strong. This does not mean that adopting such an approach is ineffective but that the evidence base is currently lacking.

A Commentary on the Need for 3D-Biologically Relevant In Vitro Environments to Investigate Astrocytes and Their Role in Central Nervous System Inflammation.

Astrocytes execute essential functions in the healthy CNS, whilst also being implicated as a limitation to functional regeneration and repair after injury. They respond to injury to minimize damage to healthy tissue whilst also attempting to seal the broken blood-brain-barrier, however, they impede recovery if they are persistent and form a permanent scar in the injured brain. As such, it is of great importance to understand the mechanism underlying the astrocytic response to injury, and this understanding is currently limited by the in vitro environments available to scientists. Biomaterials such as nanofibres and hydrogels offer great potential for the development of superior, 3D cell culture environments in which to study astrocyte behavior and phenotype. The implementation of such in vitro environments with a particularly interdisciplinary approach can improve the field's understanding of astrocytes, their role in central nervous system inflammation, and elucidate potential strategies to achieve functional regeneration.

Night-time sleep in Parkinson's disease - the potential use of Parkinson's KinetiGraph: a prospective comparative study.

BACKGROUND AND PURPOSE: Night-time sleep disturbances are important non-motor symptoms and key determinants of health-related quality of life (HRQoL) in patients with Parkinson's disease (PD). The Parkinson's KinetiGraph (PKG) can be used as an objective measure of different motor states and periods of immobility may reflect episodes of sleep. Our aim was to evaluate whether PKG can be used as an objective marker of disturbed night-time sleep in PD. METHODS: In this prospective comparative study, data from PKG recordings over six consecutive 24 h periods are compared with Hauser diaries and scales focusing on motor state, sleep and HRQoL in PD patients. Thirty-three 'non-sleepy' PD patients (PD-NS) were compared with 30 PD patients presenting with excessive daytime sleepiness (PD-EDS). The groups were matched for age, gender and Hoehn and Yahr state. RESULTS: In the PD-EDS group subjective sleep reports correlated with the PKG's parameters for quantity and quality night-time sleep, but not in the PD-NS group. There were no significant correlations of the night-time sleep quantity parameters of the Hauser diary with subjective sleep perception, neither in the PD-EDS nor in the PD-NS group. CONCLUSIONS: This first PKG based study of night-time sleep in PD suggests that PKG could be used to provide an easy to use and rough evaluation of aspects of night-time sleep and one that could flag patients where polysomnography may be required. In sleepy PD patients for instance, quantity and quality PKG parameters correlate with different aspects of sleep such as insomnia, parasomnia and restless legs syndrome.

Predominance of caudate nucleus lesions in acute ischaemic stroke patients with impairment in language and speech.

BACKGROUND AND PURPOSE: Whereas traditional views of language processing in the brain have assumed that the language function is concentrated to a limited number of cortical areas (Broca's and Wernicke's areas), current knowledge points at a much more complex system of language and speech processing involving many brain areas, both cortical and subcortical. The purpose of the current study was to make an unbiased assessment of which cerebral areas are affected in first-ever acute ischaemic stroke patients identified as having language and speech impairments according to the National Institutes of Health Stroke Scale (NIHSS). METHODS: Data from 34 patients with language and speech impairment, with a score of 1-3 on item 9 of the NIHSS, following ischaemic stroke were collected from the Lund Stroke Register. Magnetic resonance images acquired up to 20 days after stroke onset were used to create an overlap lesion image using MRIcron software. RESULTS: The classical language areas, Wernicke's and Broca's areas, were affected in less than one-fourth of the patients. The most frequently affected region was a subcortical region--the left caudate nucleus and the adjacent corona radiata. CONCLUSIONS: These findings contribute to the growing body of evidence that the basal ganglia have a crucial role in the control over language and speech processing.

Mapping parahippocampal systems for recognition and recency memory in the absence of the rat hippocampus.

The present study examined immediate-early gene expression in the perirhinal cortex of rats with hippocampal lesions. The goal was to test those models of recognition memory which assume that the perirhinal cortex can function independently of the hippocampus. The c-fos gene was targeted, as its expression in the perirhinal cortex is strongly associated with recognition memory. Four groups of rats were examined. Rats with hippocampal lesions and their surgical controls were given either a recognition memory task (novel vs. familiar objects) or a relative recency task (objects with differing degrees of familiarity). Perirhinal Fos expression in the hippocampal-lesioned groups correlated with both recognition and recency performance. The hippocampal lesions, however, had no apparent effect on overall levels of perirhinal or entorhinal cortex c-fos expression in response to novel objects, with only restricted effects being seen in the recency condition. Network analyses showed that whereas the patterns of parahippocampal interactions were differentially affected by novel or familiar objects, these correlated networks were not altered by hippocampal lesions. Additional analyses in control rats revealed two modes of correlated medial temporal activation. Novel stimuli recruited the pathway from the lateral entorhinal cortex (cortical layer II or III) to hippocampal field CA3, and thence to CA1. Familiar stimuli recruited the direct pathway from the lateral entorhinal cortex (principally layer III) to CA1. The present findings not only reveal the independence from the hippocampus of some perirhinal systems associated with recognition memory, but also show how novel stimuli engage hippocampal subfields in qualitatively different ways from familiar stimuli.

Sensory-specific anomic aphasia following left occipital lesions: data from free oral descriptions of concrete word meanings.

The present study investigated hierarchical lexical semantic structure in oral descriptions of concrete word meanings produced by a subject (ZZ) diagnosed with anomic aphasia due to left occipital lesions. The focus of the analysis was production of a) nouns at different levels of semantic specificity (e.g., "robin"-"bird"-"animal") and b) words describing sensory or motor experiences (e.g., "blue," "soft," "fly"). Results show that in contrast to healthy and aphasic controls, who produced words at all levels of specificity and mainly vision-related sensory information, ZZ produced almost exclusively nouns at the most non-specific levels and words associated with sound and movement.

Device-based 24-hour movement behaviours in adult phase III cardiac rehabilitation service-users during the COVID-19 pandemic: a mixed-methods prospective observational study.

PURPOSE: To examine changes in device-based 24-hour movement behaviours (MB), and facilitators and barriers to physical activity (PA) and exercise, during remotely-delivered cardiac rehabilitation (RDCR). MATERIALS AND METHODS: This prospective observational study used wrist-worn GENEActiv accelerometers to assess MB of 10 service-users (63 ± 10 years) at the start, middle, and end of three-months of RDCR. Barriers and facilitators to PA and exercise were explored through self-report diaries and analysed using content analysis. RESULTS: At start, service-users were sedentary for 12.6 ± 0.7 h · day-1 and accumulated most PA at a light-intensity (133.52 ± 28.57 min · day-1) - neither changed significantly during RDCR. Sleep efficiency significantly reduced from start (88.80 ± 4.2%) to the end (86.1 ± 4.76%) of CR, with values meeting health-based recommendations (≥85%). Barriers to RDCR exercise included exertional discomfort and cardiac symptoms, and reduced confidence when exercising alone. Setting meaningful PA goals, self-monitoring health targets, and having social support, facilitated PA and exercise during RDCR. CONCLUSIONS: Our RDCR programme failed to elicit significant changes in MB or sleep. To increase the likelihood of successful RDCR, it is important to promote a variety of exercise and PA options, target sedentary time, and apply theory to RDCR design, delivery, and support strategies.

Practitioners should work with service-users to understand how best to support them to maximise the benefit(s) of remotely/hybrid delivered services.Facilitating easy (and regular) access to health professionals during remotely/hybrid delivered cardiac rehabilitation (CR) will support the development of service-users' physical activity (PA) and exercise self-efficacy (i.e., confidence).Remotely/hybrid delivered CR should be informed by theory and/or behaviour change techniques to support increased PA, reduced sedentary time and improved sleep during and after CR.It is important to include strategies to reduce sedentary time in addition to targeting PA and exercise in remotely-delivered CR.

Attitudes and beliefs to the uptake and maintenance of physical activity among community-dwelling South Asians aged 60-70 years: a qualitative study.

OBJECTIVES: To identify the attitudes and beliefs associated with the uptake and adherence of physical activity among community-dwelling South Asians aged 60-70 years. STUDY DESIGN: A qualitative research study using an ethnographic approach. METHODS: Focus groups and in-depth interviews were conducted to explore motivational factors associated with initiating and maintaining physical activity. Data analysis followed the framework approach. RESULTS: Health, maintaining independence and social support were important in terms of initiating physical activity. Social support, psychosocial elements of activity, health and integrating physical activity within everyday activities were important for adherence to physical activity. The need for gendered physical activity sessions was important to initiating exercise among Muslim South Asians aged 60-70 years. CONCLUSION: Promoting active lifestyles and building physical activity in and around day-to-day activities are important strategies in increasing activity levels. However, the needs for culturally appropriate facilities, peer mentors who could assist those with language barriers, specific tailored advice, advice on integrating physical activity in everyday life and general social support could promote uptake and subsequent adherence among this population group.

White matter changes in basis pontis in small expansion FMR1 allele carriers with parkinsonism.

Examples of white matter hyperintensities (wmh) on magnetic resonance images in a basis pontis are presented in two male carriers, each of whom carry a small CGG expansion fragile X mental retardation (FMR1) allele. One carried a premutation (PM) allele of 85 CGG repeats and the other, a gray zone (GZ) allele of 47 repeats. Both were originally diagnosed with idiopathic Parkinson's disease (iPD). Similar changes are also shown in one PM carrier of 99 repeats affected with mild tremor and imbalance, who was ascertained through a fragile X syndrome family. These examples draw attention to the occurrence of wmh in a basis pontis in the carriers of small CGG expansions presenting with tremor and ataxia. Moreover, the presence of this change in GZ, as well as PM, allele carriers originally diagnosed with iPD supports our earlier suggestion that both these alleles may contribute to the neurodegenerative changes in this disorder which, in the examples presented, have been reflected by wmh, most prominent in the cerebellar peduncles and/or pontine area.

Sensitive and specific detection of α-synuclein in human plasma.

alpha-Synuclein (alphasyn) mutations, overexpression, misfolding, and aggregation are associated with Parkinson's disease. This protein has been intensively studied in neuronal systems. However, alphasyn is also present in extracellular fluids, such as cerebrospinal fluid and blood plasma. Recent studies have attempted to quantify its levels and compare these in various extracellular fluids of control and Parkinson's disease subjects. Data from these studies have been difficult to interpret, suggesting that more sensitive, standardized, and well-characterized assays of larger cohorts are required. Here, we describe the development of a new ELISA specifically for quantifying alphasyn in human plasma. An initial assay, using a commercial anti-alphasyn monoclonal antibody (211; Santa Cruz Biotechnology, Santa Cruz, CA) and based on a published protocol, was adapted for use in human plasma. In addition, we have developed a novel alphasyn-specific antibody for the assay that has very high sensitivity and signal:noise characteristics. Assays with either antibody showed high specificity for alphasyn, and detected it in a variety of sample types, including plasma. These assays can now be employed on large cohorts of patients and control subjects to determine whether plasma levels are altered in disease. Although measuring extracellular alphasyn levels may prove to be a useful biomarker of Parkinson's disease, it should also be a powerful tool for basic research aimed at understanding the normal and pathological physiology of alphasyn secretion. .

Pyramiding QTL increases seedling resistance to crown rot (Fusarium pseudograminearum) of wheat (Triticum aestivum).

Crown rot of wheat (Triticum aestivum), predominantly caused by the fungus Fusarium pseudograminearum, has become an increasingly important disease constraint in many winter cereal production regions in Australia. Our group has previously identified a range of quantitative trait loci (QTL) for partial resistance to crown rot in various bread wheat sources. Here, we report on work that has assessed the effectiveness of pyramiding QTL to improve resistance to crown rot. Two doubled haploid populations were analysed--one from a cross between two previously characterised sources of partial seedling resistance (2-49 and W21MMT70; n = 208) and one from a cross between 2-49 and the commercial variety Sunco, a source of adult field resistance (n = 134). Both populations were phenotyped for seedling resistance to crown rot. Microsatellite and DArT markers were used to construct whole genome linkage maps for use in composite interval mapping (CIM) to identify QTL. Three QTL were detected in both trials conducted on the 2-49/W21MMT70 population. These were located on chromosomes 1D (QCr.usq-1D.1), 3B (QCr.usq-3B.1) and 7A. QCr.usq-1D.1 and the previously undetected 7A QTL were inherited from 2-49. QCr.usq-3B.1, inherited from W21MMT70, was the most significant of the QTL, explaining up to 40.5% of the phenotypic variance. Three QTL were identified in multiple trials of the Sunco/2-49 population. These were located on chromosomes 1D (QCr.usq-1D.1), 2B (QCr.usq-2B.2) and 4B (QCr.usq-4B.1). Only QCr.usq-2B.2 was inherited from Sunco. QCr.usq-4B.1 was the most significant of these QTL, explaining up to 19.1% of the phenotypic variance. In the 2-49/W21MMT70 population, several DH lines performed significantly better than either parent, with the best recording an average disease severity rating of only 3.8% of that scored by the susceptible check cultivar Puseas. These lines represent a new level of seedling crown rot resistance in wheat.

Using avatars in weight management settings: A systematic review.

BACKGROUND: Obesity interventions rely predominantly on managing dietary intake and/or increasing physical activity but sustained adherence to behavioural regimens is often poor. Avatar technology is well established within the computer gaming industry and evidence suggests that virtual representations of self may impact real-world behaviour, acting as a catalyst for sustained weight loss behaviour modification. However, the effectiveness of avatar technology in promoting weight loss is unclear. AIMS: We aimed to assess the quantity and quality of empirical support for the use of avatar technologies in adult weight loss interventions. METHOD: A systematic review of empirical studies was undertaken. The key objectives were to determine if: (i) the inclusion of avatar technology leads to greater weight loss achievement compared to routine intervention; and (ii) whether weight loss achievement is improved by avatar personalisation (avatar visually reflects self). RESULTS: We identified 6 papers that reported weight loss data. Avatar-based interventions for weight loss management were found to be effective in the short (4-6 weeks) and medium (3-6 months) term and improved weight loss maintenance in the long term (12 months). Only 2 papers included avatar personalisation, but results suggested there may be some added motivational benefit. CONCLUSIONS: The current evidence supports that avatars may positively impact weight loss achievement and improve motivation. However, with only 6 papers identified the evidence base is limited and therefore findings need to be interpreted with caution.

Small CGG repeat expansion alleles of FMR1 gene are associated with parkinsonism.

Fragile X-associated tremor/ataxia syndrome (FXTAS) affects older males carrying premutation, that is, expansions of the CGG repeat (in the 55-200 range), in the FMR1 gene. The neurological changes are linked to the excessive FMR1 messenger RNA (mRNA), becoming toxic through a 'gain-of-function'. Because elevated levels of this mRNA are also found in carriers of the smaller expansion (grey zone) alleles, ranging from 40 to 54 CGGs, we tested for a possible role of these alleles in the origin of movement disorders associated with tremor. We screened 228 Australian males affected with idiopathic Parkinson's disease and other causes of parkinsonism recruited from Victoria and Tasmania for premutation and grey zone alleles. The frequencies of either of these alleles were compared with the frequencies in a population-based sample of 578 Guthrie spots from consecutive Tasmanian male newborns (controls). There was a significant excess of premutation carriers (Fisher's exact test p = 0.006). There was also a more than twofold increase in grey zone carriers in the combined sample of the Victorian and Tasmanian cases, with odds ratio (OR ) = 2.36, and 95% confidence intervals (CI): 1.20-4.63, as well as in Tasmanian cases only (OR = 2.33, 95% CI: 1.06-5.13), compared with controls. The results suggest that the FMR1 grey zone alleles, as well as premutation alleles, might contribute to the aetiology of disorders associated with parkinsonism.

A beta2 adrenergic receptor signaling complex assembled with the Ca2+ channel Cav1.2.

The existence of a large number of receptors coupled to heterotrimeric guanine nucleotide binding proteins (G proteins) raises the question of how a particular receptor selectively regulates specific targets. We provide insight into this question by identifying a prototypical macromolecular signaling complex. The beta(2) adrenergic receptor was found to be directly associated with one of its ultimate effectors, the class C L-type calcium channel Ca(v)1.2. This complex also contained a G protein, an adenylyl cyclase, cyclic adenosine monophosphate-dependent protein kinase, and the counterbalancing phosphatase PP2A. Our electrophysiological recordings from hippocampal neurons demonstrate highly localized signal transduction from the receptor to the channel. The assembly of this signaling complex provides a mechanism that ensures specific and rapid signaling by a G protein-coupled receptor.

Origins of the "nucleation" free energy in the hybridization thermodynamics of short duplex DNA.

Thermodynamic parameters deltaH(cal), deltaS(cal), and deltaG(cal) of the melting transitions for 19 short DNA/DNA duplexes ranging in length from 6 to 35 base pairs were systematically evaluated by differential scanning calorimetry melting experiments carried out at four salt concentrations from 85 mM to 1.0 M [Na+]. As expected, thermodynamic stabilities of the DNA duplexes increased with length and increasing [Na+]. From plots of deltaG25 versus duplex length, extrapolation to N = 0 provided estimates on values of deltaG(cal)25 (N = 0) as a function of [Na+], corresponding to the free-energy of the "hypothetical duplex" having zero base pairs, but occupying precisely the same molar volume as the fully base paired duplex. The values obtained for deltaG(cal)25 (N = 0) were 3.68, 5.59, 7.86, and 8.68 kcal/mol in 1.00, 0.60, 0.30, and 0.085 M Na+, respectively. These values are in reasonable agreement with published values of the nucleation or initiation free-energy, attributed to formation of the first base pair in a short duplex compared to formation of the remaining base pairs. A statistical thermodynamic formulation of the association of two strands accounting for displaced solvent was utilized to relate [Na+]-dependent deltaG(cal)25 (N = 0) values to configuration integrals for both single and duplex strands. Relative differences between two single strands in their standard states and the duplex (in its standard state), and solvent displaced during the annealing process was taken into account. This analysis provides a new vantage point to view what has historically been referred to as the helix initiation or nucleation parameter and provides an alternate interpretation and mechanism for the nucleation complex in duplex formation.