17 research outputs found
On the Kinetics of Body versus End Evaporation and Addition of Supramolecular Polymers
Although pathway-specific kinetic theories are fundamentally important to
describe and understand reversible polymerisation kinetics, they come in
principle at a cost of having a large number of system-specific parameters.
Here, we construct a dynamical Landau theory to describe the kinetics of
activated linear supramolecular self-assembly, which drastically reduces the
number of parameters and still describes most of the interesting and generic
behavior of the system in hand. This phenomenological approach hinges on the
fact that if nucleated, the polymerisation transition resembles a phase
transition. We are able to describe hysteresis, overshooting, undershooting and
the existence of a lag time before polymerisation takes off, and pinpoint the
conditions required for observing these types of phenomenon in the assembly and
disassembly kinetics. We argue that the phenomenological kinetic parameter in
our theory is a pathway controller, i.e., it controls the relative weights of
the molecular pathways through which self-assembly takes place
Stochastic Lag Time in Nucleated Linear Self-Assembly
Protein aggregation is of great importance in biology, e.g., in amyloid
fibrillation. The aggregation processes that occur at the cellular scale must
be highly stochastic in nature because of the statistical number fluctuations
that arise on account of the small system size at the cellular scale. We study
the nucleated reversible self-assembly of monomeric building blocks into
polymer-like aggregates using the method of kinetic Monte Carlo. Kinetic Monte
Carlo, being inherently stochastic, allows us to study the impact of
fluctuations on the polymerisation reactions. One of the most important
characteristic features in this kind of problem is the existence of a lag phase
before self-assembly takes off, which is what we focus attention on. We study
the associated lag time as a function of the system size and kinetic pathway.
We find that the leading order stochastic contribution to the lag time before
polymerisation commences is inversely proportional to the system volume for
large-enough system size for all nine reaction pathways tested. Finite-size
corrections to this do depend on the kinetic pathway
Endophytic Bacteria from Ocimum sanctum and Their Yield Enhancing Capabilities
Abstract Endophytes are beneficial microbes that reside intercellularly inside the plants. Interaction of endophytes with the host plants and their function within their host are important to address ecological relevance of endophyte. Four endophytic bacteria OS-9, OS-10, OS-11, and OS-12 were isolated from healthy leaves of Ocimum sanctum
Approaches in biotechnological applications of natural polymers
Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento CientfĂico e TecnolĂłgico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de NvĂel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)
Dynamic Landau theory for supramolecular self-assembly
Although pathway-specific kinetic theories are fundamentally important to describe and understand reversible polymerisation kinetics, they come in principle at a cost of having a large number of system-specific parameters. Here, we construct a dynamical Landau theory to describe the kinetics of activated linear supramolecular self-assembly, which drastically reduces the number of parameters and still describes most of the interesting and generic behavior of the system in hand. This phenomenological approach hinges on the fact that if nucleated, the polymerisation transition resembles a phase transition. We are able to describe hysteresis, overshooting, undershooting and the existence of a lag time before polymerisation takes off, and pinpoint the conditions required for observing these types of phenomenon in the assembly and disassembly kinetics. We argue that the phenomenological kinetic parameter in our theory is a pathway controller, i.e., it controls the relative weights of the molecular pathways through which self-assembly takes place
Efficient Image Retrieval Through Hybrid Feature Set and Neural Network
Images are an important part of daily life. The huge repository of digitally existing images cannot be easilycontrolled by any individual. Extensive scanning of the image database is very much essential to search a particularimage from the huge repository. In some cases, this procedure becomes very exhaustive also. As a result, if a count often thousand, lakhs or considerably more images are included in image database, then it may be transformed into atedious and never ending process. Content-based image retrieval (CBIR) is a technique, which is used for retrievingany image. This type of image retrieval procedure is centred on the actual content of image. This paper proposed amodel of hybrid feature set of Haar wavelets and Gabor features and analysed with different existing models imageretrieval. Content based image retrieval using hybrid feature set of Haar wavelets and Gabor features superiors onother models
Impact of lockdown on self-care management among patients with type 2 Diabetes Mellitus residing in Lucknow city, India â A cross-sectional study
Objective: To assess the effect of nationwide lockdown and its associated repercussion on the self-care management of Type 2 Diabetes Mellitus (T2D). Methods: Response from 1406 diabetic patients was collected against a 16 item questionnaire. Data was collected on diabetic self-management practices, behavioral aspects, psychological implications, drug availability and awareness towards the pandemic. Emphasis was on choices made by patients in the absence of guidance from physicians and impact of stress and blood sugar levels on other variables. The data was analyzed using Chi-square tests at PÂ <Â 0.05. Results: About 27% were under stress, 14.7% and 30.8% reported a change in dietary and sleep pattern. About 83% could not consult a doctor and as a result 13% stopped taking medications. Patients with stress slept less, observed a change in dietary patterns and had uncontrolled blood sugar levels (PÂ =Â 0.0001). On the contrary those without stress spent time with family and were occupied with a hobby (PÂ =Â 0.0001). Those with controlled blood sugar levels exercised more and had normal sleep patterns. Fluctuation with doses was observed among those with uncontrolled blood sugar levels in the absence of physicians consultation (PÂ =Â 0.001). Conclusion: Even though majority of study participants were not able to consult their physicians yet nearly 2/3rd were practicing Self-Monitoring of Blood Glucose (SMBG), more than half were exercising regularly, more than 2/3rds continued taking their medications and majority were following appropriate diet pattern. Stress management is a key factor during these times due to its association with other variables