Multiscaling behavior of atomic-scale friction.

The scaling behavior of friction between rough surfaces is a well-known phenomenon. It might be asked whether such a scaling feature also exists for friction at an atomic scale despite the absence of roughness on atomically flat surfaces. Indeed, other types of fluctuations, e.g., thermal and instrumental fluctuations, become appreciable at this length scale and can lead to scaling behavior of the measured atomic-scale friction. We investigate this using the lateral force exerted on the tip of an atomic force microscope (AFM) when the tip is dragged over the clean NaCl (001) surface in ultra-high vacuum at room temperature. Here the focus is on the fluctuations of the lateral force profile rather than its saw-tooth trend; we first eliminate the trend using the singular value decomposition technique and then explore the scaling behavior of the detrended data, which contains only fluctuations, using the multifractal detrended fluctuation analysis. The results demonstrate a scaling behavior for the friction data ranging from 0.2 to 2 nm with the Hurst exponent H=0.61±0.02 at a 1σ confidence interval. Moreover, the dependence of the generalized Hurst exponent, h(q), on the index variable q confirms the multifractal or multiscaling behavior of the nanofriction data. These results prove that fluctuation of nanofriction empirical data has a multifractal behavior which deviates from white noise.

Burden and associated factors for caregivers of the elderly in a developing country.

The elderly population in South Asia is growing. In Pakistan trained caregivers are scarce and culturally not acceptable. This study assessed the level of stress experienced by caregivers of the elderly and determined the association of care giving burden with different characteristics of the elderly. A cross-sectional, questionnaire based study was conducted using nonprobability purposive sampling. All consenting participants aged 60 years and above needing help with at least one activity of daily living or two instrumental activities of daily living were included. 350 participants were assessed for perceived care giver burden. Care providers were mostly female (68.9%). Half (50.3%) of the caregivers had a positive score on a perceived care burden scale. Financial impact had a strong correlation (0.79) with perceived caregiver burden. Higher dependency levels of a physical and cognitive nature posed greater burden on caregivers. Behavioural issues of the elderly such as verbal abuse and difficulty sleeping were predictors of a higher caregiver burden. Caregiver burden is a significant issue for those caring for elderly family members in Karachi, Pakistan.

Burden and associated factors for caregivers of the elderly in a developing country

The elderly population in South Asia is growing. In Pakistan trained caregivers are scarce and culturally not acceptable. This study assessed the level of stress experienced by caregivers of the elderly and determined the association of care giving burden with different characteristics of the elderly. A cross-sectional, questionnaire based study was conducted using nonprobability purposive sampling. All consenting participants aged 60 years and above needing help with at least one activity of daily living or two instrumental activities of daily living were included. 350 participants were assessed for perceived care giver burden. Care providers were mostly female [68.9%]. Half [50.3%] of the caregivers had a positive score on a perceived care burden scale. Financial impact had a strong correlation [0.79] with perceived caregiver burden. Higher dependency levels of a physical and cognitive nature posed greater burden on caregivers. Behavioural issues of the elderly such as verbal abuse and difficulty sleeping were predictors of a higher caregiver burden. Caregiver burden is a significant issue for those caring for elderly family members in Karachi, Pakistan

La population âgée d'Asie du Sud-Est connaît une augmentation. Au Pakistan, les personnels soignants formés sont rares et non acceptés d'un point de vue culturel. La présente étude avait pour objectif d'évaluer le niveau de stress des aidants de personnes âgées et de déterminer l'association entre le fardeau de soins et différentes caractéristiques propres aux personnes âgées. Une étude transversale, reposant sur un questionnaire, a été conduite en recourant à un échantillonnage non probabiliste par choix raisonné. Toutes les personnes consentantes âgées de 60 ans et plus requérant une aide pour au moins une activité de la vie quotidienne ou deux activités instrumentales de la vie quotidienne ont été incluses. Le fardeau perçu par les aidants a été évalué chez 350 participants. Les dispensateurs de soins étaient majoritairement des femmes [68,9%]. La moitié [50,3%] des aidants obtenaient des scores élevés sur l'échelle d'évaluation du fardeau de soins. L'impact financier avait une forte corrélation [0,79] avec la perception du fardeau de soins. Des niveaux de dépendance physique ou cognitive plus élevés rajoutaient au fardeau supporté par les aidants. Les problèmes comportementaux des personnes âgées tels que des insultes verbales ou des troubles du sommeil constituaient d'importants indicateurs d'un fardeau plus lourd. Le fardeau des aidants est un problème de taille pour les personnes qui prennent soin de membres âgés de leurs familles à Karachi, au Pakistan

Nuclear pore complex: biochemistry and biophysics of nucleocytoplasmic transport in health and disease.

Nuclear pore complexes (NPCs) are the gateways connecting the nucleoplasm and cytoplasm. This structures are composed of over 30 different proteins and 60-125 MDa of mass depending on type of species. NPCs are bilateral pathways that selectively control the passage of macromolecules into and out of the nucleus. Molecules smaller than 40 kDa diffuse through the NPC passively while larger molecules require facilitated transport provided by their attachment to karyopherins. Kinetic studies have shown that approximately 1000 translocations occur per second per NPC. Maintaining its high selectivity while allowing for rapid translocation makes the NPC an efficient chemical nanomachine. In this review, we approach the NPC function via a structural viewpoint. Putting together different pieces of this puzzle, this chapter confers an overall insight into what molecular processes are engaged in import/export of active cargos across the NPC and how different transporters regulate nucleocytoplasmic transport. In the end, the correlation of several diseases and disorders with the NPC structural defects and dysfunctions is discussed.