92 research outputs found

    Structural Analysis and Activity Correlation of Amphiphilic Cyclic Antimicrobial Peptides Derived from the [W\u3csub\u3e4\u3c/sub\u3eR\u3csub\u3e4\u3c/sub\u3e] Scaffold

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    In our ongoing quest to design effective antimicrobial peptides (AMPs), this study aimed to elucidate the mechanisms governing cyclic amphiphilic AMPs and their interactions with membranes. The objective was to discern the nature of these interactions and understand how peptide sequence and structure influence antimicrobial activity. We introduced modifications into the established cyclic AMP peptide, [W4R4], incorporating an extra aromatic hydrophobic residue (W), a positively charged residue (R), or the unique 2,5-diketopiperazine (DKP). This study systematically explored the structure–activity relationships (SARs) of a series of cyclic peptides derived from the [W4R4] scaffold, including the first synthesis and evaluation of [W4R4(DKP)]. Structural, dynamic, hydrophobic, and membrane-binding properties of four cyclic peptides ([W4R4], [W5R4], [W4R5], [W4R4(DKP)]) were explored using molecular dynamics simulations within a DOPC/DOPG lipid bilayer that mimics the bacterial membrane. The results revealed distinct SARs linking antimicrobial activity to parameters such as conformational plasticity, immersion depth in the bilayer, and population of the membrane binding mode. Notably, [W4R5] exhibited an optimal “activity/binding to the bacterial membrane” pattern. This multidisciplinary approach efficiently decoded finely regulated SAR profiles, laying a foundation for the rational design of novel antimicrobial peptides

    Impact of the 26 December 2003 bam earthquake on activities of daily living and instrumental activities of daily living of older people

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    Introduction: This study compares self-reported Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL) status among elderly survivors of the 2003 Bam Earthquake before, two months after, and five years after the event, and explores related determinants. Methods: A two-stage cluster survey was conducted on 210 elderly survivors in the earthquake-stricken area five years after the event. Results: Both ADL and IADL scores decreased two months after earthquake compared to prior status (p 0.05). Access to medical services were not related to level of ADL or IADL (p = 0.52 and p = 0.74, respectively). Elderly survivors with lower functional capability in terms of ADL experienced more problems in access to relief items (p = 0.04), but no similar association was found for IADL (p = 0.26). Conclusion: The Bam earthquake adversely affected functional capacity of the elderly. Disaster responders must take into account functional capacity of elders when planning for medical and relief operations. © World Association for Disaster and Emergency Medicine 2011

    Cyclic Dipeptides: The Biological and Structural Landscape with Special Focus on the Anti-Cancer Proline-Based Scaffold

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    Cyclic dipeptides, also know as diketopiperazines (DKP), the simplest cyclic forms of peptides widespread in nature, are unsurpassed in their structural and bio-functional diversity. DKPs, especially those containing proline, due to their unique features such as, inter alia, extra-rigid conformation, high resistance to enzyme degradation, increased cell permeability, and expandable ability to bind a diverse of targets with better affinity, have emerged in the last years as biologically pre-validated platforms for the drug discovery. Recent advances have revealed their enormous potential in the development of next-generation theranostics, smart delivery systems, and biomaterials. Here, we present an updated review on the biological and structural profile of these appealing biomolecules, with a particular emphasis on those with anticancer properties, since cancers are the main cause of death all over the world. Additionally, we provide a consideration on supramolecular structuring and synthons, based on the proline-based DKP privileged scaffold, for inspiration in the design of compound libraries in search of ideal ligands, innovative self-assembled nanomaterials, and bio-functional architectures

    Public health equity in refugee situations

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    Addressing increasing concerns about public health equity in the context of violent conflict and the consequent forced displacement of populations is complex. Important operational questions now faced by humanitarian agencies can to some extent be clarified by reference to relevant ethical theory. Priorities of service delivery, the allocation choices, and the processes by which they are arrived at are now coming under renewed scrutiny in the light of the estimated two million refugees who fled from Iraq since 2003

    Intelligent evacuation management systems: A review

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    Crowd and evacuation management have been active areas of research and study in the recent past. Various developments continue to take place in the process of efficient evacuation of crowds in mass gatherings. This article is intended to provide a review of intelligent evacuation management systems covering the aspects of crowd monitoring, crowd disaster prediction, evacuation modelling, and evacuation path guidelines. Soft computing approaches play a vital role in the design and deployment of intelligent evacuation applications pertaining to crowd control management. While the review deals with video and nonvideo based aspects of crowd monitoring and crowd disaster prediction, evacuation techniques are reviewed via the theme of soft computing, along with a brief review on the evacuation navigation path. We believe that this review will assist researchers in developing reliable automated evacuation systems that will help in ensuring the safety of the evacuees especially during emergency evacuation scenarios

    Poverty, social exclusion and dental caries of 12-year-old children: a cross-sectional study in Lima, Peru

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    Background: Socioeconomic differences in oral health have been reported in many countries. Poverty and social exclusion are two commonly used indicators of socioeconomic position in Latin America. The aim of this study was to explore the associations of poverty and social exclusion with dental caries experience in 12-year-old children. Methods: Ninety families, with a child aged 12 years, were selected from 11 underserved communities in Lima (Peru), using a two-stage cluster sampling. Head of households were interviewed with regard to indicators of poverty and social exclusion and their children were clinically examined for dental caries. The associations of poverty and social exclusion with dental caries prevalence were tested in binary logistic regression models. Results: Among children in the sample, 84.5% lived in poor households and 30.0% in socially excluded families. Out of all the children, 83.3% had dental caries. Poverty and social exclusion were significantly associated with dental caries in the unadjusted models (p = 0.013 and 0.047 respectively). In the adjusted model, poverty remained significantly related to dental caries (p = 0.008), but the association between social exclusion and dental caries was no longer significant (p = 0.077). Children living in poor households were 2.25 times more likely to have dental caries (95% confidence interval: 1.24; 4.09), compared to those living in non-poor households. Conclusion: There was support for an association between poverty and dental caries, but not for an association between social exclusion and dental caries in these children. Some potential explanations for these findings are discussed

    Chemokine Coreceptor Signaling in HIV-1 Infection and Pathogenesis

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    Binding of the HIV-1 envelope to its chemokine coreceptors mediates two major biological events: membrane fusion and signaling transduction. The fusion process has been well studied, yet the role of chemokine coreceptor signaling in viral infection has remained elusive through the past decade. With the recent demonstration of the signaling requirement for HIV latent infection of resting CD4 T cells, the issue of coreceptor signaling needs to be thoroughly revisited. It is likely that virus-mediated signaling events may facilitate infection in various immunologic settings in vivo where cellular conditions need to be primed; in other words, HIV may exploit the chemokine signaling network shared among immune cells to gain access to downstream cellular components, which can then serve as effective tools to break cellular barriers. This virus-hijacked aberrant signaling process may in turn facilitate pathogenesis. In this review, we summarize past and present studies on HIV coreceptor signaling. We also discuss possible roles of coreceptor signaling in facilitating viral infection and pathogenesis

    Production and Utilization of Keratin and Sericin-Based Electro-Spun Nanofibers: A Comprehensive Review

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    This article review is devoted to throw the light on the unique characteristics of keratin- and sericin-based electro-spun nanofibers which make them suitable for various applications in different fields. The principles of electro-spinning together with the various devices usually used to fabricate nanofibers are also highlighted. The chemistry of keratin and sericin bio-polymers and the methods of extraction from their respective natural resources, such as wool and natural silk fibers, were criticized. Blending of keratin or sericin with various natural and synthetic polymeric materials to improve their rheological properties to obtain electro-spinnable composite suitable for production of functional nano-fibrous mat was discussed. Incorporation of nanosized metals and metal oxides as well as bioactive materials into keratin and sericin-based electro-spun nanofibers imparts new functions to the produced nanofibres. The utilization of these functional nano-fibrous mats in biomedical, filtration and smart textile applications was illustrated. The current status and future prospects of the electro-spun nanofibers were highlighted
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