On the Sophistication of Herbal Medicines
Aruna Bakhru in Nutrition and Integrative Medicine, 2018
Such synchrony always begins the same way. As researcher Scott Camazine (2001, 19) puts it, “At a critical density a pattern arises within the system.” Thus, when a container is packed with increasing numbers of molecules, at a certain point, which can never be predicted, the random motions of the billions and billions of molecules will suddenly show an alteration in behavior. They will spontaneously synchronize, begin to act in concert, active cooperating, become tightly coupled together into one, interacting whole. The whole which comes into being at that moment of synchrony exhibits a collective, macroscopically ordered state of being. A unique more-than-the-sum-of-the-parts organism emerges of which the smaller subunits (the molecules) are now only a part. The molecules have self-organized. And … it just happens. Like water turning to ice. From a simple decrease of 1° of temperature a phase change occurs. Something new comes into being.
Instrumentation in Urology
Anthony R. Mundy, John M. Fitzpatrick, David E. Neal, Nicholas J. R. George in The Scientific Basis of Urology, 2010
Nitinol is known as a shape memory alloy (SMA), in other words an alloy that remembers its shape. SMAs are able to undergo a molecular rearrangement in the solid phase (Fig. 11). This means that during a solidstate phase change a molecular rearrangement occurs, but the molecules remain closely packed so that the substance remains a solid (10). These phase changes, known as martensite and austenite, involve the rearrangement of the position of particles within the crystal structure of the solid. Below the transition temperature, Nitinol is in the martensite phase and can be bent into various shapes. To fix the “parent shape,’’ the metal must be held in position and heated to about 500°C. The high temperature causes the atoms to arrange themselves into the most compact and regular pattern possible resulting in a rigid cubic arrangement known as the austenite phase. Above the transition temperature, Nitinol reverts from the martensite to the austenite phase that changes it back into its parent shape. This cycle of shape deformation and recovery can be repeated multiple times. The use of a SMA in urology is well illustrated by the MemokathTM range of stents.
Predicting Stability in Rheologically Modified Systems
Laba Dennis in Rheological Proper ties of Cosmetics and Toiletries, 2017
Recently, differential thermal analysis (DTA) has become a practical screen for structural changes in mixtures. Differential scanning calorimetry (DSC) is the form of DTA that is most widely applied, although some applications of differential volume have been fruitful. Differential calorimetry has identified isomorphs of triglycerides in creams, and liquid crystalline mesophases. DSC provides an excellent evaluation method for stress-induced changes, and can even provide an early warning for stability problems. It cannot, however, supplant accelerated stress testing. Phase transitions are easily identified in both quantitative heat energy (latent heat of melting) and temperature of phase change. Liquid crystal phases are easily identified this way.
Improving Knowledge and Increasing Use of a Screening Tool in an Outpatient Psychiatric Clinic
Published in Issues in Mental Health Nursing, 2020
Mary Kiesewetter, Marsha Snyder, Suzanna Kitten
In 1951, Kurt Lewin developed the classic change theory, derived from field theory in social science (Lewin, 1951). Lewin’s theory of change is broken into three simple phases: unfreezing, changing, and refreezing. He theorized the more involved a person is with understanding the need for change, the more likely they are to take the steps toward that change (White & Dudley-Brown, 2012). The first stage, “unfreezing” involved beginning to change the way the individual or organization thinks about the problem at hand (Lewin, 1951). This period of time is important for the individuals involved in the change to be educated about the improvements of the new way (Lewin, 1951). The second phase “change” is rather self-explanatory. It involves the actual actions of change taking place (Lewin, 1951). Not all persons involved in the first phase will be willing to carry through the second phase (Lewin, 1951). Finally, the third phase “refreezing” involves the new way becoming part of the culture of the individuals and/or organization (Lewin, 1951). This phase continues on until if or when a new change is warranted, and the cycle begins all over again.
AuNPs as an important inorganic nanoparticle applied in drug carrier systems
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Wen Li, Zhiwen Cao, Rui Liu, Linlin Liu, Hui Li, Xiang Li, Youwen Chen, Cheng Lu, Yuanyan Liu
AuNPs can be modified with heat-sensitive materials to realise drug release [154]. For example, Lajunen et al. [155] developed liposomal drug carriers which were formulated using a heat-sensitive composition with star- or rod-shaped AuNPs. AuNPs convert light energy into heat and release it into the lipid bilayer, causing an increase in the local temperature that causes double leakage of the liposome and triggers drug release. Phase change material (PCM) is a material with a large latent heat of fusion that melts and solidifies at a certain temperature. There are three forms of PCM: liquid-gas, solid-solid, and solid-liquid. Solid-liquid PCM is now widely used in basic research and practical application [156]. The PCM which is applied in a drug release system should have good biocompatibility and a precise critical solution temperature with a slightly higher melting point than physiological temperature [157]. lauric acid [158], fatty acid and 1-tetradecanol [156] are frequently used PCMs. Poudel et al. [159] reported a new strategy in which hollow silver-gold nanoshells are encapsulated in hollow mesoporous silica as an effective platform for the release of anticancer drugs. The mesopores were blocked with the heat-sensitive PCM lauric acid to achieve drug-controlled release by photothermal action. In addition, there are also many dual-responsive drug release systems such as pH/near-infra-red dual-triggered drug release [160], GSH/near-infra-red dual-triggered drug release [161], GSH/pH dual-triggered drug release [146] and other responsive drug release systems [162,163].
Microemulsion-based delivery of triamcinolone acetonide to posterior segment of eye using chitosan and butter oil as permeation enhancer: an in vitro and in vivo investigation
Published in Journal of Microencapsulation, 2018
Nidhi Raval, Dignesh Khunt, Manju Misra
%Transmittance of TA ME, TA CH ME and TA:BO ME was found to be 98.60 ± 0.03, 98.73 ± 0.02 and 79.5 ± 0.04, respectively. The globule sizes of 66.06 ± 0.32, 78.42 ± 1.5 and 97.3 ± 2.50 nm with PDI of 0.195 ± 0.120, 0.201 ± 0.013 and 0.234 ± 0.090 for TA ME, TA CH ME and TA:BO ME, respectively, indicated that all three were a monodisperse system having narrow size distribution. An important criterion for ocular delivery is globule size, since smaller globules (less than 100 nm) exhibit larger surface area, increasing rate of drug permeation. At a smaller size, a higher amount of drug can be transported across cornea efficiently which can be retained in cul-de-sac cavity of the eye due to their small size and ability to adhere to tissue surface. These also prevent availability of drug at non-target sites reducing side effects and frequency of dosing (Hironaka et al., 2009; Inokuchi et al., 2010; Ying et al., 2013; Kaur and Kakkar, 2014). It is reported that the granularity of BO is because of the presence of glycerides of higher-melting saturated acids, especially palmitic and stearic acid in it. Any single glyceride can exist in four crystal forms, which exist in dynamic equilibrium with each other resulting in differences in the physical appearance of fats. Upon storage, the occurrence of crystallisation or total solidification of fat results in phase change and equilibrium. This phenomenon could explain the decrease in transmission of TA:BO ME and also increase in size upon addition of BO in TA ME.
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