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Synthetic Seeds Vis-A-Vis Cryopreservation: An Efficient Technique for Long-Term Preservation of Endangered Medicinal Plants
Published in Amit Baran Sharangi, K. V. Peter, Medicinal Plants, 2023
Md. Nasim Ali, Syandan Sinha Ray
Synthetic seed may be either hydrated or desiccated in nature. The first hydrated synthetic seed was developed by Redenbaugh et al. (1984) for alfalfa and celery while desiccated synthetic seed was developed by Kitto and Janick (1985) for carrot (Ara et al., 2000). The hydrated artificial seeds are made up of encapsulating plant materials in hydrogel coats while the desiccated seeds are either naked or encapsulated in polyoxyethylene glycol followed by its desiccation (Kikowska and Thiem, 2011). Desiccation may be done either slowly over a period of one or two weeks sequentially decreasing relative humidity or rapidly by unsealing the petri dishes and leaving them on the bench overnight to dry under airflow. These types of synthetic seeds are prepared for desiccation tolerance while encapsulated seeds are produced for desiccation susceptible plants (Ara et al., 2000).
Hysteroscopic Vaporization of Uterine Myoma
Published in John C. Petrozza, Uterine Fibroids, 2020
In electrovaporization, the current utilized in the electrode is set at a higher power than that utilized in standard cutting. Therefore, as the electrode contacts fresh tissue cells, it provides a high enough current density to vaporize the contacted tissue cells. However, if the contact on the same spot is maintained, the underlying tissue cells start to desiccate instead of vaporizing because of the increasing resistance generated by the dried-out tissue. The degree of desiccation is governed by the quality of the contact to the tissue and the time spent on that spot by the electrode. The longer the contact, the deeper the desiccation effect. Since the procedure is performed using glycine as a distending medium, the desiccated tissue is constantly rehydrated, making it available for vaporization on a subsequent pass. In short, electrovaporization vaporizes the unwanted tissue, provides hemostasis and prevents water reabsorption by the development of a zone of desiccation below the vaporized tissue. The heat that is generated produces a zone of coagulation in the adjoining layer of tissue, and the depth of vaporization depends on duration of contact, resistance (debris on the electrode) and wattage of the generator.
Reconstruction in head and neck surgical oncology
Published in Neeraj Sethi, R. James A. England, Neil de Zoysa, Head, Neck and Thyroid Surgery, 2020
Kishan Ubayasiri, Andrew Foreman
The internal nasal lining is often the hardest layer to reconstruct. The use of a local septal flap or a flap of facial alar skin can be used if appropriate. Where a paramedian forehead flap has been raised an underlying pericranial flap can also be raised for reconstructing nasal lining. However, it is prone to desiccation and consequent partial necrosis and should only be used when there is no other option.
Therapeutic advances in wound healing
Published in Journal of Dermatological Treatment, 2022
André Oliveira, Sandra Simões, Andreia Ascenso, Catarina Pinto Reis
CDOT usually consists of devices that provide a continuous oxygen supply to the wound site. As opposed to HBOT and THOT, these devices are portable and deliver oxygen at normospheric pressure and slower flow rates directly to the wound bed that must be covered with a moist wound dressing to allow oxygen diffusion. In fact, without humidification, desiccation can occur preventing oxygen solubilization in the wound fluid, and consequently, reducing its transport into the tissue. Although THOT uses high flow rates (40 L/min) which can cause desiccation, these devices provide intermittent therapy (90 min/day, five days a week), and thus not require a moist environment. It has fewer reported risks and side effects than previous modalities and offers easy therapeutic delivery (152). Despite that studies regarding this new class of devices are limited, some have shown THOT could be beneficial in the healing of DFUs, sickle cell disease ulcers as well as in the treatment of recalcitrant and painful wounds as an adjunct (159–162).
Application of multi-component fluid model in studies of the origin of skin burns during electrosurgical procedures
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Marija Radmilović-Radjenović, Martin Sabo, Branislav Radjenović
The effect of the current on the tissue is illustrated in Figure 1 that shows various stages of electrocoagulation that can used to control bleeding during surgery (Taheri et al. 2014). (a) The process starts with coagulation. (b) At the end of coagulation, the more superficial coagulated tissue dries out (desiccation) and become less electrically conductive, potentially preventing the current from continuing to flow. (c) Sparking may then occur through the nonconductive desiccated layer, causing disruption of this layer, the passage of more current, more heat production, and deeper thermal damage. The timing of the occurrence of desiccation during coagulation depends on the rate of increase in temperature that is the result of current density. With lower current density, there may be deep coagulation before desiccation happens. Therefore, for deep coagulation, a relatively low power should be chosen to provide slow coagulation and late occurrence of desiccation keeping in mind that a very low power may not be able to ensure the coagulation.
Polysaccharide nanoparticles for oral controlled drug delivery: the role of drug–polymer and interpolymer interactions
Published in Expert Opinion on Drug Delivery, 2020
Annalisa Bianchera, Ruggero Bettini
Lyophilization is the preferred technique to dry NPs, especially when heat-sensitive APIs, such as proteins, are included in the formulation: the major concern when dealing with protein freeze-drying is the prevention of stress, that often requires the addition of protectants. The choice of cryoprotectant depends on the type of polymer involved in the formation of NPs [80]. For example, Almalik et al. [81] evaluated the effect of different cryoprotectants on chitosan NPs coated with hyaluronic acid or alginate, finding that trehalose and sucrose gave the best results in terms of maintenance of particle size and prevention of aggregation; this was confirmed for the freeze drying of protein-based NPs [82,83]. The effect of freeze-drying on particle characteristics is commonly compared to the effect given by spray-drying, as described by Rampino et al. [84] who selected trehalose as the best cryoprotectant for both techniques. Also, Cerchiara et al. [85] compared freeze-dried and spray-dried nanoparticles prepared from chitosan/TPP for colon-specific delivery of vancomycin. Micro- and nanoparticles were produced by the two techniques, resulting in different release profile of the antibiotic glycopeptide: the nanoformulation obtained by spray drying showed the best profile in terms of drug release and antimicrobial activity in vitro. Lyophilization can have denaturizing effects on pharmaceuticals; moreover, resulting cakes need a secondary procedure to obtain fine particles. This step can be avoided if desiccation is performed by spray drying [86] or spray congealing.