scholarly journals Biocidal and bioresorbable chitosan/triclosan/collagen matrixes

Innovation ◽  
2019 ◽  
pp. 1
Author(s):  
GE Villanueva-Ornelas ◽  
RE Núñez-Anita ◽  
MC Arenas-Arrocena ◽  
GH Luévano-Colmenero
Keyword(s):  
Biomedical Application ◽  
Antimicrobial Effect ◽  
Matrix Group ◽  
Dental Surgery ◽  
Culture Cells ◽  
Antimicrobial Materials ◽  
The Matrix ◽  
Bioresorbable Material ◽  
Nih 3T3 ◽  
Over Time

Biomedical application of biomaterials has increased in recent years. Some preferred characteristics of these materials are biocompatibility, biodegradability and antimicrobial effect. We are facing a constant search for antimicrobial materials to be used instead of antibiotics therapy to reduce the possibility of dental surgery contamination. In this study, biocidal, bioresorbable and non-toxic matrixes were synthesized from chitosan, triclosan and collagen. Three experimental groups received different chitosan/collagen combinations, (0.5:1, 0.75:1 and 1:1), all with the same dose of triclosan (0.1%). Antimicrobial effect was measured by the inhibition of S. aureus growth. Moreover, matrixes were placed in a PBS-collagenase solution to measure degradation over time; matrix residues were evaluated at 1, 4, and 7 days. Finally, cell toxicity of each matrix was analyzed on NIH-3T3 fibroblast cells. As a result, inhibition of S. aureus growth was similar in the three established experimental groups of matrixes vs vancomycin antibiotic as control. These data suggest potent antimicrobial effect of chitosan/triclosan/collagen matrixes. Degradation over time showed that 80% of the matrix was degraded after 4 days, thus suggesting that chitosan/triclosan/collagen matrixes are bioresorbable material. On the other hand, viability of NIH-3T3 cells was between 60% to 74% after 24 h and prior to matrix exposition to culture cells. These data indicate light toxicity in the 0.5:1 and 0.75:1 matrix groups and non-toxic effect in the 1:1 matrix group. By taking together these data, we propose the application of chitosan/triclosan/collagen matrixes to prevent bacterial contamination after dental surgery.

Soil and Stream Water Chemistry During Spring Snowmelt

1992 ◽  
Vol 23 (1) ◽  
pp. 13-26 ◽  
Author(s):  
W. H. Hendershot ◽  
L. Mendes ◽  
H. Lalande ◽  
F. Courchesne ◽  
S. Savoie
Keyword(s):  
Stream Water ◽  
Base Cations ◽  
Stream Chemistry ◽  
Stream Water Chemistry ◽  
The Matrix ◽  
Adsorption Desorption ◽  
The Relationship ◽  
Best Fit ◽  
Spring Snowmelt ◽  
Over Time

In order to determine how water flowpath controls stream chemistry, we studied both soil and stream water during spring snowmelt, 1985. Soil solution concentrations of base cations were relatively constant over time indicating that cation exchange was controlling cation concentrations. Similarly SO4 adsorption-desorption or precipitation-dissolution reactions with the matrix were controlling its concentrations. On the other hand, NO3 appeared to be controlled by uptake by plants or microorganisms or by denitrification since their concentrations in the soil fell abruptly as snowmelt proceeded. Dissolved Al and pH varied vertically in the soil profile and their pattern in the stream indicated clearly the importance of water flowpath on stream chemistry. Although Al increased as pH decreased, the relationship does not appear to be controlled by gibbsite. The best fit of calculated dissolved inorganic Al was obtained using AlOHSO4 with a solubility less than that of pure crystalline jurbanite.

scholarly journals Gold Nanoparticles Synthesis and Antimicrobial Effect on Fibrous Materials

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1067
Author(s):  
Behnaz Mehravani ◽  
Ana Isabel Ribeiro ◽  
Andrea Zille
Keyword(s):  
Gold Nanoparticles ◽  
Antimicrobial Properties ◽  
Antimicrobial Effect ◽  
Environmental Concerns ◽  
Fibrous Materials ◽  
Barrier Material ◽  
Future Studies ◽  
Textile Materials ◽  
Promising Strategy ◽  
Antimicrobial Materials

Depositing nanoparticles in textiles have been a promising strategy to achieve multifunctional materials. Particularly, antimicrobial properties are highly valuable due to the emergence of new pathogens and the spread of existing ones. Several methods have been used to functionalize textile materials with gold nanoparticles (AuNPs). Therefore, this review highlighted the most used methods for AuNPs preparation and the current studies on the topic in order to obtain AuNPs with suitable properties for antimicrobial applications and minimize the environmental concerns in their production. Reporting the detailed information on the functionalization of fabrics, yarns, and fibers with AuNPs by different methods to improve the antimicrobial properties was the central objective. The studies combining AuNPs and textile materials have opened valuable opportunities to develop antimicrobial materials for health and hygiene products, as infection control and barrier material, with improved properties. Future studies are needed to amplify the antimicrobial effect of AuNPs onto textiles and minimize the concerns related to the synthesis.

The influence of different geometries of matrix/scaffold on the remodeling process of a bone and bioresorbable material mixture with voids

2015 ◽  
Vol 22 (5) ◽  
pp. 969-987 ◽  
Author(s):  
Ivan Giorgio ◽  
Ugo Andreaus ◽  
Tomasz Lekszycki ◽  
Alessandro Della Corte
Keyword(s):  
Bone Growth ◽  
Matrix Material ◽  
Porous Solids ◽  
Artificial Material ◽  
Matrix Deposition ◽  
Aspect Ratios ◽  
Adopted Model ◽  
The Matrix ◽  
Bioresorbable Material

Since internal architecture greatly influences crucial factors for tissue regeneration, such as nutrient diffusion, cell adhesion and matrix deposition, scaffolds have to be carefully designed, keeping in mind case-specific mechanical, mass transport and biological requirements. However, customizing scaffold architecture to better suit conflicting requirements, such as biological and mechanical ones, remains a challenging issue. Recent advances in printing technologies, together with the synthesis of novel composite biomaterials, have enabled the fabrication of various scaffolds with defined shape and controlled in vitro behavior. Thus, the influence of different geometries of the assemblage of the matrix and scaffold on the remodeling processes of living bone and artificial material should be investigated. To this end, two implant shapes are considered in this paper, namely a circular inclusion and a rectangular groove of different aspect ratios. A model of a mixture of bone tissue and bioresorbable material with voids was used to numerically analyze the physiological balance between the processes of bone growth and resorption and artificial material resorption in a plate-like sample. The adopted model was derived from a theory for the behavior of porous solids in which the matrix material is elastic and the interstices are void of material.

scholarly journals Mortality Risk and The Progression of The Electronic Frailty Index and Hospital Frailty Risk Score Over Time

2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Joe Hollinghurst ◽  
Alan Watkins
Keyword(s):  
Risk Score ◽  
Frailty Index ◽  
Time Frame ◽  
Time Dependent ◽  
Cox Models ◽  
Hazard Ratios ◽  
Increased Risk ◽  
The Matrix ◽  
Time Dependent Covariates ◽  
Over Time

IntroductionThe electronic Frailty Index (eFI) and the Hospital Frailty Risk Score (HFRS) have been developed in primary and secondary care respectively. Objectives and ApproachOur objective was to investigate how frailty progresses over time, and to include the progression of frailty in a survival analysis.To do this, we performed a retrospective cohort study using linked data from the Secure Anonymised Information Linkage Databank, comprising 445,771 people aged 65-95 living in Wales (United Kingdom) on 1st January 2010. We calculated frailty, using both the eFI and HFRS, for individuals at quarterly intervals for 8 years with a total of 11,702,242 observations. ResultsWe created a transition matrix for frailty states determined by the eFI (states: fit, mild, moderate, severe) and HFRS (states: no score, low, intermediate, high), with death as an absorbing state. The matrix revealed that frailty progressed over time, but that on a quarterly basis it was most likely that an individual remained in the same state. We calculated Hazard Ratios (HRs) using time dependent Cox models for mortality, with adjustments for age, gender and deprivation. Independent eFI and HFRS models showed increased risk of mortality as frailty severity increased. A combined eFI and HFRS revealed the highest risk was primarily determined by the HFRS and revealed further subgroups of individuals at increased risk of an adverse outcome. For example, the HRs (95% Confidence Interval) for individuals with an eFI as fit, mild, moderate and severe with a high HFRS were 18.11 [17.25,19.02], 20.58 [19.93,21.24], 21.45 [20.85,22.07] and 23.04 [22.34,23.76] respectively with eFI fit and no HFRS score as the reference category. ConclusionFrailty was found to vary over time, with progression likely in the 8-year time-frame analysed. We refined HR estimates of the eFI and HFRS for mortality by including time dependent covariates.

scholarly journals Votive altars: domestic signals to inhabit the Sacred

2019 ◽  
Vol 2 (3) ◽  
pp. 31
Author(s):  
Claudio Gambardella ◽  
Valentina Sapio
Keyword(s):  
Visual Arts ◽  
Word Meaning ◽  
Living Space ◽  
Mediterranean Countries ◽  
Catholic Religion ◽  
The Matrix ◽  
Human World ◽  
The Mediterranean ◽  
The City ◽  
Over Time

“Sacred” is an Indo-European word meaning “separate”. The Sacred, therefore, [. . . is] a quality that is inherent in that which has relation and contact with powers that man, not being able to dominate, perceives as superior to himself, and as such attributable to a dimension [. . . ] thought however as ”separate” and ”other” with respect to the human world » Galimberti, (2000). The so-called votive altar, autonomous or attached to a major building often present in the Mediterranean countries, belong to the dimension of the Sacred.Votive altars - present in an old neighborhood of peasant origin in the suburbs of Naples called Ponticelli - are almost always placed in the interstices between street and courtyard (a self-built residential typology modeled over time by the inhabitants and which often forms the matrix of many neighborhoods popular Neapolitan). They keep and exhibit little sculptures and drawings of Jesus, Madonnas, and Saints of the Catholic religion, mixed with ancestors portraits and photos of relatives dead of the inhabitants, drawing on the ancient domestic cult of the Romans of Lari and Penati; it is certainly not a consciously cultured reference, but a mysterious ”feeling” that is common among primitive and popular cultures and that unravels through the centuries unscathed. Placed at the entrance of the living space, the altar expresses the sign of a difference, of a territorial change, separates ”ours” from ”yours”, welcomes, does not reject, but marks an open and inclusive threshold.With the paper, we want to study this phenomenon of ”primitive” culture and not regulated by laws, a mix of diffuse sacredness and popular magic, deepening the ”design” aspects of it, building an abacus in which to highlight potential and free references to the visual arts of these ”design works without designers”, and finding out new signs of the Sacred in the City in our time.

THE INFLUENCE OF THE COMPOSITION AND SIZE OF THE FRACTIONS OF THE COMPOSITE GRAVEL FILLER WITH AN EPOXY MATRIX ON ITS WEAR

2021 ◽  
Vol 3 (144) ◽  
pp. 100-107
Author(s):  
Aleksandr M. Mikhal’chenkov ◽  
◽  
Anna A. Tyureva ◽  
Ivan A. Borshchevskiy ◽  
Larisa S. Kiseleva
Keyword(s):  
Wear Resistance ◽  
Composite Materials ◽  
Epoxy Matrix ◽  
Protective Coatings ◽  
Research Purpose ◽  
Effective Diameter ◽  
Wear Process ◽  
The Matrix ◽  
Sand And Gravel ◽  
Over Time

The widespread use of polymer-based composite materials made it possible to replace expensive metal alloys, increase the strength indicators of structures and improve tribotechnical properties. Their use as protective coatings for structural elements operating in an abrasive environment has yielded good results in increasing wear resistance, which is especially important for parts of tillage tools. (Research purpose) The research purpose is in studying the influence of the composition and size of the fractions of the composite gravel filler with an epoxy matrix on its wear. (Materials and мethods) The article considers five composite materials with different compositions. The prototypes were hollow cylinders with dimensions that provide the contact area necessary for the passage of all processes of abrasive wear. The abrasive composition consisted of a mixture of sand and gravel with a fraction size of about 30-40 millimeters. (Results and discussion) The changes in the wear over time are directly proportional and this confirms the classical views on the wear process. The experiments was conducted on the installation of authors’ design. (Conclusions) The wear over time for experimental composites is the same and is expressed in a straight- line relationship; the maximum wear resistance is a composite in which gravel particles have a size of 2.25 millimeters with its content in the matrix of about 60 mass parts. At the same time, gravel with an effective diameter of 2.25 millimeters creates optimal conditions for self-organization of the wear process and provides a relatively low value of the friction coefficient.

scholarly journals A recognition algorithm for non-generic classical groups over finite fields

1999 ◽  
Vol 67 (2) ◽  
pp. 223-253 ◽  
Author(s):  
Azice C. Niemeyer ◽  
Cheryl E. Praeger
Keyword(s):  
Finite Field ◽  
Finite Fields ◽  
Special Linear Group ◽  
Theoretical Background ◽  
Recognition Algorithm ◽  
Large Field ◽  
Matrix Group ◽  
Classical Groups ◽  
Original Algorithm ◽  
The Matrix

AbstractIn a previous paper the authors described an algorithm to determine whether a group of matrices over a finite field, generated by a given set of matrices, contains one of the classical groups or the special linear group. The algorithm was designed to work for all sufficiently large field sizes and dimensions of the matrix group. However, it did not apply to certain small cases. Here we present an algorithm to handle the remaining cases. The theoretical background of the algorithm presented in this paper is a substantial extension of that needed for the original algorithm.

scholarly journals The matrix, group processes and dramatherapy

2012 ◽  
Vol 39 (1) ◽  
pp. 60-65 ◽  
Author(s):  
Richard Hougham
Keyword(s):  
Group Processes ◽  
Matrix Group ◽  
The Matrix

Functionalized Antimicrobial Thin Films Based on Antibiotic Imbedded in Polymer Matrix for Implants Coating

2015 ◽  
Vol 1128 ◽  
pp. 144-148
Author(s):  
Laura Floroian ◽  
Mihaela Badea ◽  
Dan Floroian ◽  
Marius Moga ◽  
Cornel Samoila
Keyword(s):  
Thin Films ◽  
Polymer Matrix ◽  
Antibiotic Susceptibility ◽  
Antimicrobial Effect ◽  
Biological Properties ◽  
Metallic Substrate ◽  
Bacterial Strains ◽  
Chronic Infections ◽  
Antimicrobial Materials ◽  
Antibiotic Release

In this study we investigated the possibility to use in implantology of a new composite made from antibiotic imbedded in polymer matrix with goal to merge the mechanical advantages of the metallic substrate with the excellent corrosion protection of the polymer and antimicrobial effect of the antibiotics. Furthermore the addition of small quantity of bioactive glass allows the antibiotic release and hastens the osteointegration. The biological properties of the coatings were tested including the microbial viability using Gram - and Gram + bacterial strains with known antibiotic susceptibility behavior. The proposed system could be used for development of new antimicrobial materials or strategies for fighting medical biofilm pathogens often implicated in the occurrence of chronic infections.

Community, Justice, and Jihad

1987 ◽  
Vol 4 (1) ◽  
pp. 13-30
Author(s):  
Mona Abul-Fadl
Keyword(s):  
Historical Consciousness ◽  
Political Involvement ◽  
Group Consciousness ◽  
Way Of Life ◽  
Islamic World ◽  
Community Justice ◽  
The Matrix ◽  
Basic Concepts ◽  
The Individual ◽  
Over Time

The CommunityIslam is more than a Faith in the heart of every Muslim. It is also a sourceof identity. The fundamental rites and devotions constituting its 'Pillars'simultaneously confirm the faith of the individual and affirm the bonds ofCommunity. It is this symbiosis of Faith and Community that over time gaverise to a Muslim historical consciousness. From it too stems the predilectionfor an active social and political involvement on the part of Muslims as groupsand individuals.The elements of this consciousness emanate from an Islamic world-viewand they have interacted in various situations and contexts to condition theresponses of Muslims throughout history. To explore these elements it isessential to examine three basic concepts: Umma, 'Adl, and Jihad or respectively,Community, Justice and the Just Striving. All three concepts areembedded in the matrix of Tawhid and are interwoven and integrally related toone another. In their context a Muslim group consciousness has been forgedfor over a millenium. As such, they justly provide the parameters forunderstanding Muslim history and forecasting the future of Islam in theworld.Cornmunity/al'Umma: Legacy of Prophethood andVehicle of Muslim ConsciousnessThe Community in Islam is a purposeful entity composed of a group, or ajamah whose members, by virtue of a common faith, way of life and sense of ...

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