scholarly journals Biological Effects ofSpirulina(Arthrospira) Biopolymers and Biomass in the Development of Nanostructured Scaffolds

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Michele Greque de Morais ◽  
Bruna da Silva Vaz ◽  
Etiele Greque de Morais ◽  
Jorge Alberto Vieira Costa
Keyword(s):  
Materials Science ◽  
Biological Effects ◽  
Essential Fatty Acids ◽  
Synthetic Polymers ◽  
Tissue Cultures ◽  
The Past ◽  
Interdisciplinary Field ◽  
Pure Cultures ◽  
Tissue Rejection ◽  
Scientific Fields

Spirulinais produced from pure cultures of the photosynthetic prokaryotic cyanobacteriaArthrospira. For many years research centers throughout the world have studied its application in various scientific fields, especially in foods and medicine. The biomass produced fromSpirulinacultivation contains a variety of biocompounds, including biopeptides, biopolymers, carbohydrates, essential fatty acids, minerals, oligoelements, and sterols. Some of these compounds are bioactive and have anti-inflammatory, antibacterial, antioxidant, and antifungal properties. These compounds can be used in tissue engineering, the interdisciplinary field that combines techniques from cell science, engineering, and materials science and which has grown in importance over the past few decades.Spirulinabiomass can be used to produce polyhydroxyalkanoates (PHAs), biopolymers that can substitute synthetic polymers in the construction of engineered extracellular matrices (scaffolds) for use in tissue cultures or bioactive molecule construction. This review describes the development of nanostructured scaffolds based on biopolymers extracted from microalgae and biomass fromSpirulinaproduction. These scaffolds have the potential to encourage cell growth while reducing the risk of organ or tissue rejection.

The Characteristics of a Pair of Dual Binary Canonical Frames Generated by Refinable Functions

2012 ◽  
Vol 461 ◽  
pp. 864-867
Author(s):  
Zhong Yin Chen ◽  
Jian Tang Zhao
Keyword(s):  
Materials Science ◽  
Refinable Functions ◽  
Wavelet Frame ◽  
Wavelet Frames ◽  
Science And Engineering ◽  
Binary Function ◽  
The Past ◽  
Interdisciplinary Field ◽  
Popular Subject ◽  
Compactly Supported Functions

Materials science is an interdisciplinary field applyingthe properties of matter to various areas of science and engineering. Wavelet analysis has become a popular subject in researching into materials science during the past twenty years. Nowadays, it has been developed a mathematical br- anch. In this paper, we show that there exist binary wavelet frames generated by several compactly supported functions which have good dual binary wavelet frames, but for which the canonical dual binary wavelet frame does not consist of wavelets. That is to say, the canonical dual binary wavelet frame cannot be generated by the translations and dilations of a single binary function.

The Contribution of Intermediate-Voltage, High-Resolution Electron Microscopy In Materials Science: An Appraisal

1990 ◽  
Vol 48 (1) ◽  
pp. 478-479
Author(s):  
John L. Hutchison
Keyword(s):  
High Resolution ◽  
Materials Science ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
The Past ◽  
Resolution Electron ◽  
Extreme Sensitivity ◽  
Electron Microscopes ◽  
New Generation ◽  
Small Metal Particles

Over the past five years or so the development of a new generation of high resolution electron microscopes operating routinely in the 300-400 kilovolt range has produced a dramatic increase in resolution, to around 1.6 Å for “structure resolution” and approaching 1.2 Å for information limits. With a large number of such instruments now in operation it is timely to assess their impact in the various areas of materials science where they are now being used. Are they falling short of the early expectations? Generally, the manufacturers’ claims regarding resolution are being met, but one unexpected factor which has emerged is the extreme sensitivity of these instruments to both floor-borne and acoustic vibrations. Successful measures to counteract these disturbances may require the use of special anti-vibration blocks, or even simple oil-filled dampers together with springs, with heavy curtaining around the microscope room to reduce noise levels. In assessing performance levels, optical diffraction analysis is becoming the accepted method, with rotational averaging useful for obtaining a good measure of information limits. It is worth noting here that microscope alignment becomes very critical for the highest resolution.In attempting an appraisal of the contributions of intermediate voltage HREMs to materials science we will outline a few of the areas where they are most widely used. These include semiconductors, oxides, and small metal particles, in addition to metals and minerals.

Therapeutic Perspectives of Food Bioactive Peptides: A Mini Review

2019 ◽  
Vol 26 (9) ◽  
pp. 664-675
Author(s):  
Sulochana Priya
Keyword(s):  
Bioactive Peptides ◽  
Marine Organism ◽  
Biological Effects ◽  
Amide Bond ◽  
Therapeutic Effects ◽  
Specific Sequence ◽  
The Past ◽  
Cancer Immunity ◽  
Microbial Infections ◽  
Diverse Origin

Bioactive peptides are short chain of amino acids (usually 2-20) that are linked by amide bond in a specific sequence which have some biological effects in animals or humans. These can be of diverse origin like plant, animal, fish, microbe, marine organism or even synthetic. They are successfully used in the management of many diseases. In recent years increased attention has been raised for its effects and mechanism of action in various disease conditions like cancer, immunity, cardiovascular disease, hypertension, inflammation, diabetes, microbial infections etc. Bioactive peptides are more bioavailable and less allergenic when compared to total proteins. Food derived bioactive peptides have health benefits and its demand has increased tremendously over the past decade. This review gives a view on last two years research on potential bioactive peptides derived from food which have significant therapeutic effects.

Cucurbitacins as Anticancer Agents: A Patent Review

2019 ◽  
Vol 14 (2) ◽  
pp. 133-143 ◽  
Author(s):  
Hidayat Hussain ◽  
Ivan R. Green ◽  
Muhammad Saleem ◽  
Khanzadi F. Khattak ◽  
Muhammad Irshad ◽  
...  
Keyword(s):  
Anticancer Agents ◽  
Wide Spectrum ◽  
Biological Effects ◽  
Therapeutic Effects ◽  
Cytotoxic Effects ◽  
Natural Sources ◽  
Oh Groups ◽  
Drug Candidates ◽  
The Past ◽  
Wide Range

Background: Cucurbitacins belong to a group of tetracyclic triterpenoids that display a wide range of biological effects. In the past, numerous cucurbitacins have been isolated from natural sources and many active compounds have been synthesized using the privileged scaffold in order to enhance its cytotoxic effects. Objective: his review covers patents on the therapeutic effects of natural cucurbitacins and their synthetic analogs published during the past decade. By far, the majority of patents published are related to cancer and Structure-Activity Relationships (SAR) of these compounds are included to lend gravitas to this important class of natural products. Methods: The date about the published patents was downloaded via online open access patent databases. Results: Cucurbitacins display significant cytotoxic properties, in particular cucurbitacins B and D which possess very potent effects towards a number of cancer cells. Numerous cucurbitacins isolated from natural sources have been derivatized through chemical modification at the C(2)-OH and C(25)- OH groups. Most importantly, an acyl ester of the C(25)-OH and, iso-propyl, n-propyl and ethyl ether groups of the C(2)-OH demonstrated the most increased cytotoxic activity. Conclusion: The significant cytotoxic effects of natural and semi-synthetic cucurbitacins make them attractive as new drug candidates. Moreover, cucurbitacins have the capability to form conjugates with other anticancer drugs which will synergistically enhance their anticancer effects. The authors believe that in order to get lead compounds, there should be a greater focus on the synthesis of homodimers, heterodimers, and halo derivatives of cucurbitacins. In the opinion of the authors the analysis of the published patents on the cucurbitacins indicates that these compounds can be developed into a regimen to treat a wide spectrum of cancers.

SOMOphilic Alkynylation Using Acetylenic Sulfones as Functional Reagents

2021 ◽  
Author(s):  
Danhua Ge ◽  
Xin Wang ◽  
Xue-Qiang Chu
Keyword(s):  
Drug Discovery ◽  
Organic Synthesis ◽  
Materials Science ◽  
Polymer Chemistry ◽  
The Past ◽  
Acetylenic Sulfones

The past decades have witnessed a boom in alkynylation mainly owing to the importance of alkynyl-containing molecules in organic synthesis, drug discovery, polymer chemistry, and materials science. Besides conventional strategies,...

scholarly journals Chitosan-Based Nanocomposite Polymeric Membranes for Water Purification—A Review

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2091
Author(s):  
Angela Spoială ◽  
Cornelia-Ioana Ilie ◽  
Denisa Ficai ◽  
Anton Ficai ◽  
Ecaterina Andronescu
Keyword(s):  
Water Purification ◽  
Antioxidant Activities ◽  
Low Cost ◽  
Synthetic Polymers ◽  
Water Systems ◽  
Polymeric Membranes ◽  
Wastewater Purification ◽  
Toxic Compounds ◽  
The Past ◽  
Materials Used

During the past few years, researchers have focused their attention on developing innovative nanocomposite polymeric membranes with applications in water purification. Natural and synthetic polymers were considered, and it was proven that chitosan-based materials presented important features. This review presents an overview regarding diverse materials used in developing innovative chitosan-based nanocomposite polymeric membranes for water purification. The first part of the review presents a detailed introduction about chitosan, highlighting the fact that is a biocompatible, biodegradable, low-cost, nontoxic biopolymer, having unique structure and interesting properties, and also antibacterial and antioxidant activities, reasons for using it in water treatment applications. To use chitosan-based materials for developing nanocomposite polymeric membranes for wastewater purification applications must enhance their performance by using different materials. In the second part of the review, the performance’s features will be presented as a consequence of adding different nanoparticles, also showing the effect that those nanoparticles could bring on other polymeric membranes. Among these features, pollutant’s retention and enhancing thermo-mechanical properties will be mentioned. The focus of the third section of the review will illustrate chitosan-based nanocomposite as polymeric membranes for water purification. Over the last few years, researchers have demonstrated that adsorbent nanocomposite polymeric membranes are powerful, important, and potential instruments in separation or removal of pollutants, such as heavy metals, dyes, and other toxic compounds presented in water systems. Lastly, we conclude this review with a summary of the most important applications of chitosan-based nanocomposite polymeric membranes and their perspectives in water purification.

The use of complex microbial soil communities in Mars simulation experiments

2008 ◽  
Vol 7 (2) ◽  
pp. 169-176
Author(s):  
Kai Finster ◽  
Aviaja A. Hansen ◽  
Lars Liengaard ◽  
Karina Mikkelsen ◽  
Tommy Kristoffersen ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Simulation Studies ◽  
Interesting Consequence ◽  
Deep Biosphere ◽  
Simulation Experiments ◽  
The Past ◽  
Number Of Microorganisms ◽  
Comprehensive Picture ◽  
Pure Cultures ◽  
Survival Potential

AbstractMars simulation studies have in the past mainly investigated the effect of the simulation conditions such as UV radiation, low pressure and temperature on pure cultures and much has been learnt about the survival potential of sporeformers such asBacillus subtilis. However, this approach has limitations as the studies only investigate the properties of a very limited number of microorganisms. In this paper we propose that Mars simulations should be carried out with complex microbial communities of Martian analogues such as permafrost or the deep biosphere. We also propose that samples from these environments should be studied by a number of complementary methods and claim that these methods in combination can provide a comprehensive picture of how imposed Martian conditions affect the microbial community and in particular the survival of its constituents – microbes as well as biological material in general. As an interesting consequence this approach can lead to the isolation of bacteria, which are more recalcitrant to the imposed Martian conditions than the pure cultures that have previously been studied.

Exercise Physiology From 1980 to 2020: Application of the Natural Sciences

2021 ◽  
pp. 1-10
Author(s):  
Jane A. Kent ◽  
Kate L. Hayes
Keyword(s):  
Human Performance ◽  
Exercise Physiology ◽  
Natural Sciences ◽  
The Past ◽  
Interdisciplinary Field ◽  
Advanced Technologies ◽  
Health And Disease ◽  
Fundamental Research ◽  
Research Questions ◽  
Underlying Mechanisms

The field of exercise physiology has enjoyed tremendous growth in the past 40 years. With its foundations in the natural sciences, it is an interdisciplinary field that is highly relevant to human performance and health. The focus of this review is on highlighting new approaches, knowledge, and opportunities that have emerged in exercise physiology over the last four decades. Key among these is the adoption of advanced technologies by exercise physiologists to address fundamental research questions, and the expansion of research topics to range from molecular to organismal, and population scales in order to clarify the underlying mechanisms and impact of physiological responses to exercise in health and disease. Collectively, these advances have ensured the position of the field as a partner in generating new knowledge across many scientific and health disciplines.

scholarly journals LASTING BIOLOGICAL EFFECTS OF EARLY ENVIRONMENTAL INFLUENCES

1968 ◽  
Vol 127 (4) ◽  
pp. 801-818 ◽  
Author(s):  
Egilde Seravalli ◽  
René Dubos
Keyword(s):  
Growth Rate ◽  
Mouse Embryo ◽  
Bacterial Infections ◽  
Biological Effects ◽  
Intestinal Flora ◽  
Adult Life ◽  
Tissue Cultures ◽  
Depressing Effect ◽  
Genetic Stock ◽  
Adult Weight

Certain specific-pathogen-free (SPF) mice bred and maintained under semiprotected conditions have an intestinal flora which is qualitatively simpler (although not quantitatively smaller) than that of mice of the same genetic stock produced under ordinary conditions. They are also heavier at weaning time, grow at a faster rate, and reach a greater adult weight than ordinary mice. When SPF mice are contaminated per os shortly after birth with certain bacterial cultures isolated from the intestinal contents of adult ordinary mice, these bacteria multiply extensively throughout the gastrointestinal tract and persist at extremely high levels until weaning time. Such bacterial infections do not affect significantly either weaning weight, growth rate, or maximum adult weight. In contrast, weight depression could be consistently brought about by contaminating newborn SPF mice per os with bacteria-free filtrates of homogenates of intestines from ordinary mice. The weight-depressing agent passed through Millipore discs of 0.45 and 0.22 µ porosity, but was held back at 0.10 µ porosity. The depression of weight caused by either intestine homogenate or filtrates thereof could be detected within a few days after contamination (of 2 day old mice) and persisted throughout the adult life of the contaminated animals. When intestine homogenate of the SPF mice used in this study were introduced per os into newborn SPF mice, they did not affect their growth rate or adult weight. On several occasions, but not consistently, bacteria-free filtrates capable of depressing the weight curve of SPF mice produced alterations in the appearance of tissue cultures of BHK-21 and mouse embryo cells. When tissue cultures so infected were introduced into newborn SPF mice, the weight of these animals was depressed early and lastingly. An agent exhibiting weight-depressing activity has been transferred from mouse to mouse over many passages by contaminating newborn SPF animals per os. Weight depression was achieved with extremely small doses of material (10–5 ml of intestine homogenate of 10–4 of mouse embryo culture). Under these conditions, none of the animals showed obvious signs of disease except reduced weight. Only very young SPF mice (preferably less than 3 days old) proved susceptible to the weight-depressing effect of the filtrates of intestine homogenates or of infected tissue cultures prepared therefrom. After oral contamination, it took approximately 1 wk before the intestinal homogenate obtained from contaminated animals exhibited a high level of weight-depressing activity. The growth-depressing effect could be transmitted from one generation to the next by mating SPF mice that had been contaminated shortly after birth and that were consequently smaller than control SPF animals.

scholarly journals Recent Advances in Zwitterionic Hydrogels: Preparation, Property, and Biomedical Application

Gels ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 46
Author(s):  
Sihang Liu ◽  
Jingyi Tang ◽  
Fangqin Ji ◽  
Weifeng Lin ◽  
Shengfu Chen
Keyword(s):  
Immune System ◽  
Polyethylene Glycol ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
Synthetic Polymers ◽  
Human Environment ◽  
The Past ◽  
Recent Advances ◽  
Nonspecific Protein Adsorption ◽  
Anionic Groups

Nonspecific protein adsorption impedes the sustainability of materials in biologically related applications. Such adsorption activates the immune system by quick identification of allogeneic materials and triggers a rejection, resulting in the rapid failure of implant materials and drugs. Antifouling materials have been rapidly developed in the past 20 years, from natural polysaccharides (such as dextran) to synthetic polymers (such as polyethylene glycol, PEG). However, recent studies have shown that traditional antifouling materials, including PEG, still fail to overcome the challenges of a complex human environment. Zwitterionic materials are a class of materials that contain both cationic and anionic groups, with their overall charge being neutral. Compared with PEG materials, zwitterionic materials have much stronger hydration, which is considered the most important factor for antifouling. Among zwitterionic materials, zwitterionic hydrogels have excellent structural stability and controllable regulation capabilities for various biomedical scenarios. Here, we first describe the mechanism and structure of zwitterionic materials. Following the preparation and property of zwitterionic hydrogels, recent advances in zwitterionic hydrogels in various biomedical applications are reviewed.

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