51 research outputs found

    Irreversible Aging Dynamics and Generic Phase Behavior of Aqueous Suspensions of Laponite

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    In this work we study the aging behavior of aqueous suspension of Laponite having 2.8 weight % concentration using rheological tools. At various salt concentration all the samples demonstrate orientational order when observed using crossed polarizers. In rheological experiments we observe inherent irreversibility in the aging dynamics which forces the system not to rejuvenate to the same state in the shear melting experiment carried out at a later date since preparation. The extensive rheological experiments carried out as a function of time elapsed since preparation demonstrate the self similar trend in the aging behavior irrespective of the concentration of salt. We observe that the exploration of the low energy states as a function of aging time is only kinetically affected by the presence of salt. We estimate that the energy barrier to attain the low energy states decreases linearly with increase in the concentration of salt. The observed superposition of all the elapsed time and the salt concentration dependent data suggests that the aging that occurs in low salt concentration systems over a very long period is qualitatively similar to the aging behavior observed in systems with high salt concentration over a shorter period.Comment: 27 pages, 8 figures. Langmuir, in pres

    Cross validation of bi-modal health-related stress assessment

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    This study explores the feasibility of objective and ubiquitous stress assessment. 25 post-traumatic stress disorder patients participated in a controlled storytelling (ST) study and an ecologically valid reliving (RL) study. The two studies were meant to represent an early and a late therapy session, and each consisted of a "happy" and a "stress triggering" part. Two instruments were chosen to assess the stress level of the patients at various point in time during therapy: (i) speech, used as an objective and ubiquitous stress indicator and (ii) the subjective unit of distress (SUD), a clinically validated Likert scale. In total, 13 statistical parameters were derived from each of five speech features: amplitude, zero-crossings, power, high-frequency power, and pitch. To model the emotional state of the patients, 28 parameters were selected from this set by means of a linear regression model and, subsequently, compressed into 11 principal components. The SUD and speech model were cross-validated, using 3 machine learning algorithms. Between 90% (2 SUD levels) and 39% (10 SUD levels) correct classification was achieved. The two sessions could be discriminated in 89% (for ST) and 77% (for RL) of the cases. This report fills a gap between laboratory and clinical studies, and its results emphasize the usefulness of Computer Aided Diagnostics (CAD) for mental health care

    Liposome encapsulated Disulfiram inhibits NFκB pathway and targets breast cancer stem cells in vitro and in vivo

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    Breast cancer stem cells (BCSCs) are pan-resistant to different anticancer agents and responsible for cancer relapse. Disulfiram (DS), an antialcoholism drug, targets CSCs and reverses pan-chemoresistance. The anticancer application of DS is limited by its very short half-life in the bloodstream. This prompted us to develop a liposomeencapsulated DS (Lipo-DS) and examine its anticancer effect and mechanisms in vitro and in vivo. The relationship between hypoxia and CSCs was examined by in vitro comparison of BC cells cultured in spheroid and hypoxic conditions. To determine the importance of NFκB activation in bridging hypoxia and CSC-related pan-resistance, the CSC characters and drug sensitivity in BC cell lines were observed in NFκB p65 transfected cell lines. The effect of Lipo-DS on the NFκB pathway, CSCs and chemosensitivity was investigated in vitro and in vivo. The spheroid cultured BC cells manifested CSC characteristics and pan-resistance to anticancer drugs. This was related to the hypoxic condition in the spheres. Hypoxia induced activation of NFκB and chemoresistance. Transfection of BC cells with NFκB p65 also induced CSC characters and pan-resistance. Lipo-DS blocked NFκB activation and specifically targeted CSCs in vitro. Lipo-DS also targeted the CSC population in vivo and showed very strong anticancer efficacy. Mice tolerated the treatment very well and no significant in vivo nonspecific toxicity was observed. Hypoxia induced NFκB activation is responsible for stemness and chemoresistance in BCSCs. Lipo-DS targets NFκB pathway and CSCs. Further study may translate DS into cancer therapeutics

    MKS3/TMEM67 mutations are a major cause of COACH syndrome, a joubert syndrome related disorder with liver involvement

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    The acronym COACH defines an autosomal recessive condition of Cerebellar vermis hypo/ aplasia, Oligophrenia, congenital Ataxia, Coloboma and Hepatic fibrosis. Patients present the “molar tooth sign”, a midbrain-hindbrain malformation pathognomonic for Joubert Syndrome (JS) and Related Disorders (JSRDs). The main feature of COACH is congenital hepatic fibrosis (CHF), resulting from malformation of the embryonic ductal plate. CHF is invariably found also in Meckel syndrome (MS), a lethal ciliopathy already found to be allelic with JSRDs at the CEP290 and RPGRIP1L genes. Recently, mutations in the MKS3 gene (approved symbol TMEM67), causative of about 7% MS cases, have been detected in few Meckel-like and pure JS patients. Analysis of MKS3 in 14 COACH families identified mutations in 8 (57%). Features such as colobomas and nephronophthisis were found only in a subset of mutated cases. These data confirm COACH as a distinct JSRD subgroup with core features of JS plus CHF, which major gene is MKS3, and further strengthen gene-phenotype correlates in JSRDs

    Time-aging time-stress superposition in soft glass under tensile deformation field

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    We have studied the tensile deformation behaviour of thin films of aging aqueous suspension of Laponite, a model soft glassy material, when subjected to a creep flow field generated by a constant engineering normal stress. Aqueous suspension of Laponite demonstrates aging behaviour wherein it undergoes time dependent enhancement of its elastic modulus as well as its characteristic relaxation time. However, under application of the normal stress, the rate of aging decreases and in the limit of high stress, the aging stops with the suspension now undergoing a plastic deformation. Overall, it is observed that the aging that occurs over short creep times at small normal stresses is same as the aging that occurs over long creep times at large normal stresses. This observation allows us to suggest an aging time - process time - normal stress superposition principle, which can predict rheological behaviour at longer times by carrying out short time tests.Comment: 26 pages, 7 figures, To appear in Rheologica Act

    An Ontological Approach to Inform HMI Designs for Minimizing Driver Distractions with ADAS

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    ADAS (Advanced Driver Assistance Systems) are in-vehicle systems designed to enhance driving safety and efficiency as well as comfort for drivers in the driving process. Recent studies have noticed that when Human Machine Interface (HMI) is not designed properly, an ADAS can cause distraction which would affect its usage and even lead to safety issues. Current understanding of these issues is limited to the context-dependent nature of such systems. This paper reports the development of a holistic conceptualisation of how drivers interact with ADAS and how such interaction could lead to potential distraction. This is done taking an ontological approach to contextualise the potential distraction, driving tasks and user interactions centred on the use of ADAS. Example scenarios are also given to demonstrate how the developed ontology can be used to deduce rules for identifying distraction from ADAS and informing future designs

    Guidelines for diagnosis and management of the cobalamin-related remethylation disorders cblC, cblD, cblE, cblF, cblG, cblJ and MTHFR deficiency

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    BACKGROUND: Remethylation defects are rare inherited disorders in which impaired remethylation of homocysteine to methionine leads to accumulation of homocysteine and perturbation of numerous methylation reactions. OBJECTIVE: To summarise clinical and biochemical characteristics of these severe disorders and to provide guidelines on diagnosis and management. DATA SOURCES: Review, evaluation and discussion of the medical literature (Medline, Cochrane databases) by a panel of experts on these rare diseases following the GRADE approach. KEY RECOMMENDATIONS: We strongly recommend measuring plasma total homocysteine in any patient presenting with the combination of neurological and/or visual and/or haematological symptoms, subacute spinal cord degeneration, atypical haemolytic uraemic syndrome or unexplained vascular thrombosis. We strongly recommend to initiate treatment with parenteral hydroxocobalamin without delay in any suspected remethylation disorder; it significantly improves survival and incidence of severe complications. We strongly recommend betaine treatment in individuals with MTHFR deficiency; it improves the outcome and prevents disease when given early
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