548 research outputs found

    Effective Rheology of Bubbles Moving in a Capillary Tube

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    We calculate the average volumetric flux versus pressure drop of bubbles moving in a single capillary tube with varying diameter, finding a square-root relation from mapping the flow equations onto that of a driven overdamped pendulum. The calculation is based on a derivation of the equation of motion of a bubble train from considering the capillary forces and the entropy production associated with the viscous flow. We also calculate the configurational probability of the positions of the bubbles.Comment: 4 pages, 1 figur

    Inhibition of HIV virus by neutralizing Vhh attached to dual functional liposomes encapsulating dapivirine

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    Although highly active antiretroviral therapy (HAART) has greatly improved the life expectancy of HIV/AIDS patients, the treatment is not curative. It is a global challenge which fosters an urgent need to develop an effective drug or neutralizing antibody delivery approach for the prevention and treatment of this disease. Due to the low density of envelope spikes with restricted mobility present on the surface of HIV virus, which limit the antibody potency and allow virus mutation and escape from the immune system, it is important for a neutralizing antibody to form bivalent or multivalent bonds with the virus. Liposome constructs could fulfil this need due to the flexible mobility of the membrane with its attached antibodies and the capacity for drug encapsulation. In this study, we evaluated the neutralization activity of a range of liposome formulations in different sizes coated with anti-gp120 llama antibody fragments (Vhhs) conjugated via either non-covalent metal chelation or a covalent linkage. The non-covalent construct demonstrated identical binding affinity to HIV-1 envelope glycoprotein gp120 and neutralizing ability for HIV virus as free Vhh. Although covalently linked Vhh showed significant binding affinity to gp120, it unexpectedly had a lower neutralization potency. This may be due to the comparability in size of the viral and liposome particles restricting the number which can be bound to the liposome surface so involving only a fraction of the antibodies, whereas non-covalently attached antibodies dissociate from the surface after acting with gp120 and free the remainder to bind further viruses. Covalently conjugated Vhh might also trigger the cellular uptake of a liposome-virion complex. To explore the possible ability of the antibody-coated liposomes to have a further function, we encapsulated the hydrophobic antiviral drug dapivirine into both of the non-covalently and covalently conjugated liposome formulations, both of which revealed high efficacy in reducing viral replication in vitro. Thus, dual function liposomes may lead to a novel strategy for the prophylaxis of HIV/AIDS by combining the neutralizing activity of Vhh with antiviral effects of high drug concentrations

    ROS release by PPARβ/δ-null fibroblasts reduces tumor load through epithelial antioxidant response.

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    Tumor stroma has an active role in the initiation, growth, and propagation of many tumor types by secreting growth factors and modulating redox status of the microenvironment. Although PPARβ/δ in fibroblasts was shown to modulate oxidative stress in the wound microenvironment, there has been no evidence of a similar effect in the tumor stroma. Here, we present evidence of oxidative stress modulation by intestinal stromal PPARβ/δ, using a FSPCre-Pparb/d <sup>-/-</sup> mouse model and validated it with immortalized cell lines. The FSPCre-Pparb/d <sup>-/-</sup> mice developed fewer intestinal polyps and survived longer when compared with Pparb/d <sup>fl/fl</sup> mice. The pre-treatment of FSPCre-Pparb/d <sup>-/-</sup> and Pparb/d <sup>fl/fl</sup> with antioxidant N-acetyl-cysteine prior DSS-induced tumorigenesis resulted in lower tumor load. Gene expression analyses implicated an altered oxidative stress processes. Indeed, the FSPCre-Pparb/d <sup>-/-</sup> intestinal tumors have reduced oxidative stress than Pparb/d <sup>fl/fl</sup> tumors. Similarly, the colorectal cancer cells and human colon epithelial cells also experienced lower oxidative stress when co-cultured with fibroblasts depleted of PPARβ/δ expression. Therefore, our results establish a role for fibroblast PPARβ/δ in epithelial-mesenchymal communication for ROS homeostasis

    Quality of Life and its associated factors among caregivers of patients with dementia – A cross-sectional study in Kuching, Sarawak, Malaysia

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    This study aimed to determine the quality of life and its associated factors among caregivers of patients with dementia in Kuching, Sarawak, Malaysia. Methods: This cross-sectional study was carried out among caregivers for dementia patients who visited three main hospitals in Kuching, Sarawak. Using a validated questionnaire, data was obtained based on socio-demographic profile, patient and caregiving characteristics, supports needs by caregivers, and quality of life (QoL) of caregivers modified from Zarit Burden Interview (ZBI), Hospital Anxiety and Depression Scale (HADS) and Evaluation’s Scale of the Caregiver’s QoL. Results: A total of 217 caregivers participated with response rate of 99.6%, with 67.3% female and 63.1% Chinese. Most respondent provide care for their parents (62.7%), and stay with patients (67.3%). Average duration of care was 4.2 years (SD±3.72). Resource referral (M=3.52, SD±1.334) and education support (M=3.67, SD±1.054) was highest need. Majority respondents experienced little to no burden (59%). Most respondents were not depressed (98.1%). The QoL of respondents was satisfactory (M=41.36, SD±25.840). Gender of caregivers, patients with behavioural and psychological symptoms of dementia, duration of caregiving, respite care need, caregiver disability or illness, belonging support need, education support need were significantly associated with QoL of caregivers (p<0.05). Conclusion: This study on QoL of caregivers of dementia patients in Sarawak, Malaysia shows that it can be influenced by many factors, both at the caregivers’ level as well as the patients themselves. Therefore, intervention should aim at patients and their caregivers, and within community and healthcare settings

    Using theory to improve low back pain care in Australian Aboriginal primary care: a mixed method single cohort pilot study

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    Background: Low back pain (LBP) care is frequently discordant with research evidence. This pilot study evaluated changes in LBP care following a systematic, theory informed intervention in a rural Australian Aboriginal Health Service. We aimed to improve three aspects of care; reduce inappropriate LBP radiological imaging referrals, increase psychosocial oriented patient assessment and, increase the provision of LBP self-management information to patients. Methods: Three interventions to improve care were developed using a four-step systematic implementation approach. A mixed methods pre/post cohort design evaluated changes in the three behaviours using a clinical audit of LBP care in a six month period prior to the intervention and then following implementation. In-depth interviews elicited the perspectives of involved General Practitioners (GPs). Qualitative analysis was guided by the theoretical domains framework. Results: The proportion of patients who received guideline inconsistent imaging referrals (GICI) improved from 4.1 GICI per 10 patients to 0.4 (95 % CI for decrease in rate: 1.6 to 5.6) amongst GPs involved in the intervention. Amongst non-participating GPs (locum/part-time GPs who commenced post-interventions) the rate of GICI increased from 1.5 to 4.4 GICI per 10 patients (95 % CI for increase in rate: .5 to 5.3). There was a modest increase in the number of patients who received LBP self-management information from participating GPs and no substantial changes to psychosocial oriented patient assessments by any participants; however GPs qualitatively reported that their behaviours had changed. Knowledge and beliefs about consequences were important behavioural domains related to changes. Environmental and resource factors including protocols for locum staff and clinical tools embedded in patient management software were future strategies identified. Conclusions: A systematic intervention model resulted in partial improvements in LBP care. Determinants of practice change amongst GPs were increased knowledge of clinical guidelines, education delivered by someone considered a trusted source of information, and awareness of the negative consequences of inappropriate practices, especially radiological imaging on patient outcomes. Inconsistent and non-evidence based practices amongst locum GPs was an issue that emerged and will be a significant future challenge. The systematic approach utilised is applicable to other services interested in improving LBP care

    Mental Health Status and Its Associated Factors Among Caregivers of Psychiatric Patients in Kuching, Sarawak

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    Introduction: Caregivers have a high risk of mental health disorders. The quality of patient care is inseparable from the mental health status of caregivers. The objective of this research was to study the mental health status among caregivers of psychiatric patients and its associated factors. Method: A cross-sectional study was conducted among 198 caregivers in Kuching from January till July 2014. The respondents were recruited using systematic sampling and were required to provide information on sociodemographic and environmental factors as well as complete the Hospital Anxiety and Depression Scale (HADS) questionnaire. The data was analysed using the IBM SPSS Statistical Software Version 20.0. Results: The prevalence rates of anxiety and depression among caregivers were 32.8% and 27.8%, respectively. The caregiver’s age (OR=0.97, 95% CI = 0.953 - 0.996), the perception of caregiving as an economic burden (OR= 2.70, 95% CI= 1.256 - 5.803) and the dependence of the patient (OR= 2.27, 95% CI= 1.087 - 4.719) were associated with anxiety. A caregiver who was male (OR= 2.21, 95% CI= 1.143 - 4.262), a caretaker who held the perception that a patient was dependent on them (OR=2.53, 95% CI= 1.203 - 5.337) , and a caretaker who lacked stress-coping skills (OR=2.48, 95% CI= 1.030 - 5.973) were found to be significant factors in depression. Conclusion: A high prevalence of probable anxiety and depression among caregivers points to the need to screen caregivers. There is a vital need to train healthcare workers to be able to detect early anxiety and depression. Culturally sensitive research should be carried out for different ethnicity, and improving the support system for caregivers is necessary

    Alignment of the ALICE Inner Tracking System with cosmic-ray tracks

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    37 pages, 15 figures, revised version, accepted by JINSTALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10^5 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.Peer reviewe

    Ecological divergence of Chaetopteryx rugulosa species complex (Insecta, Trichoptera) linked to climatic niche diversification

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    Climate is often considered to be an important, but indirect driver of speciation. Indeed, environmental factors may contribute to the formation of biodiversity, but to date this crucial relationship remains largely unexplored. Here we investigate the possible role of climate, geological factors, and biogeographical processes in the formation of a freshwater insect species group, the Chaetopteryx rugulosa species complex (Trichoptera) in the Western Balkans. We used multi-locus DNA sequence data to establish a dated phylogenetic hypothesis for the group. The comparison of the dated phylogeny with the geological history of the Western Balkans shows that lineage formation coincided with major past Earth surface and climatic events in the region. By reconstructing present-day habitat conditions (climate, bedrock geology), we show that the lineages of C. rugulosa species complex have distinct climatic but not bedrock geological niches. Without exception, all splits associated with Pliocene/Pleistocene transition led to independent, parallel split into ‘warm’ and ‘cold’ sister lineages. This indicates a non-random diversification on the C. rugulosa species complex associated with late Pliocene climate in the region. We interpreted the results as the diversification of the species complex were mainly driven by ecological diversification linked to past climate change, along with geographical isolation

    Quality control of B-lines analysis in stress Echo 2020

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    Background The effectiveness trial “Stress echo (SE) 2020” evaluates novel applications of SE in and beyond coronary artery disease. The core protocol also includes 4-site simplified scan of B-lines by lung ultrasound, useful to assess pulmonary congestion. Purpose To provide web-based upstream quality control and harmonization of B-lines reading criteria. Methods 60 readers (all previously accredited for regional wall motion, 53 B-lines naive) from 52 centers of 16 countries of SE 2020 network read a set of 20 lung ultrasound video-clips selected by the Pisa lab serving as reference standard, after taking an obligatory web-based learning 2-h module ( http://se2020.altervista.org ). Each test clip was scored for B-lines from 0 (black lung, A-lines, no B-lines) to 10 (white lung, coalescing B-lines). The diagnostic gold standard was the concordant assessment of two experienced readers of the Pisa lab. The answer of the reader was considered correct if concordant with reference standard reading ±1 (for instance, reference standard reading of 5 B-lines; correct answer 4, 5, or 6). The a priori determined pass threshold was 18/20 (≥ 90%) with R value (intra-class correlation coefficient) between reference standard and recruiting center) > 0.90. Inter-observer agreement was assessed with intra-class correlation coefficient statistics. Results All 60 readers were successfully accredited: 26 (43%) on first, 24 (40%) on second, and 10 (17%) on third attempt. The average diagnostic accuracy of the 60 accredited readers was 95%, with R value of 0.95 compared to reference standard reading. The 53 B-lines naive scored similarly to the 7 B-lines expert on first attempt (90 versus 95%, p = NS). Compared to the step-1 of quality control for regional wall motion abnormalities, the mean reading time per attempt was shorter (17 ± 3 vs 29 ± 12 min, p < .01), the first attempt success rate was higher (43 vs 28%, p < 0.01), and the drop-out of readers smaller (0 vs 28%, p < .01). Conclusions Web-based learning is highly effective for teaching and harmonizing B-lines reading. Echocardiographers without previous experience with B-lines learn quickly.info:eu-repo/semantics/publishedVersio
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