scholarly journals Freeze-Concentrated Phase and State Transition Temperatures of Mixtures of Low and High Molecular Weight Cryoprotectants

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Alma J. Flores-Ramírez ◽  
Pedro García-Coronado ◽  
Alicia Grajales-Lagunes ◽  
Raúl González García ◽  
Miguel Abud Archila ◽  
...  
Keyword(s):  
State Transition ◽  
Frozen Storage ◽  
Thermal Transition ◽  
Transition Temperatures ◽  
Calorimetric Measurements ◽  
Mathematical Expressions ◽  
Mass Fractions ◽  
Long Term Preservation ◽  
Selection Of

Although numerous studies have been conducted on the use of cryoprotectants to prevent the deterioration of food during freezing and frozen storage, scarce reports exist on the thermal transition properties of aqueous cryoprotectant solutions at frozen temperatures. The selection of a suitable cryoprotective medium for the long-term preservation of food requires knowledge of the effects of cryoprotectants and their concentration on the freeze-concentrated unfrozen phase and state transition temperatures known asTg′,Tm′, andTm. Calorimetric measurements were conducted to determine theTg′,Tm′, andTmvalues of thirty frozen aqueous solutions containing maltodextrin, polydextrose, and glucose, in which a distance-based experimental design was used for mixtures of four components to establish their corresponding mass fractions in the mixtures. Thermograms, measured during heating/rewarming from –70 to 20°C, were used to identify the glass transition and freezing temperatures. Mathematical expressions forTg′,Tm′, andTmas a function of the mass fractions of cryoprotectants and water and their interactions (p< 0.05) were developed to aid the formulation of cryoprotective media involving more than two cryoprotectants for adequate frozen conservation of high and intermediate moisture foodstuffs.

scholarly journals How can we improve our web collection? An evaluation of webarchiving at the KB National Library of the Netherlands (2007–2017)

2017 ◽  
Vol 27 (2) ◽  
pp. 94-107 ◽  
Author(s):  
Barbara Sierman ◽  
Kees Teszelszky
Keyword(s):  
The Netherlands ◽  
Selection Criteria ◽  
National Library ◽  
Open Archival Information System ◽  
Legal Restrictions ◽  
Long Term Preservation ◽  
Initial Selection ◽  
The Web ◽  
Selection Of

In 2007, the Koninklijke Bibliotheek, the Dutch National Library (KB-NL), started the project ‘webarchiving’ based on a selection of Dutch websites. The initial selection of 1000 websites has currently grown into over 12,000 selected websites, crawled at different intervals. Although due to legal restrictions the current use is limited to the KB-NL reading room, it is important that the KB-NL includes the requirements of the (future) users in its approach to creating a web collection. With respect to the long-term preservation of the collection, we also need to incorporate the requirements for long-term archiving in our approach, as described in the Open Archival Information System (OAIS) Model ISO 14721: 2012. This article describes the results of a research project on webarchiving and the web collection of archived sites in the KB-NL, investigating the following questions. What is webarchiving in the Netherlands? What are the selection criteria of KB-NL and how are these related to what can be found on the Dutch web by the contemporary user? What is the influence of the choice of tools we use to harvest the final archived website? Do we know enough of the value of the web collection and the potential usage of it by researchers and how can we improve this value? This article will describe the outcomes of the research, the conclusions and advice that can be drawn from it and it is hoped will inspire broader discussions about the essence of creating web collections for long-term preservation as part of cultural heritage.

scholarly journals Cryoprotective effect of trehalose and maltose on washed and frozen stored beef meat

2011 ◽  
Vol 29 (No. 1) ◽  
pp. 15-23 ◽  
Author(s):  
D. Kovačević ◽  
K. Mastanjević
Keyword(s):  
Differential Scanning Calorimetry ◽  
Protein Solubility ◽  
Frozen Storage ◽  
Thermal Transition ◽  
Scanning Calorimetry ◽  
Beef Meat ◽  
Native Proteins ◽  
Mass Fractions ◽  
Extractable Protein ◽  
Meat Samples

The cryoprotective effects of trehalose and maltose (w = 2&ndash;10%) on washed beef meat were investigated. Washed beef meat produced from fresh beef meat was frozen and stored for 360 days at &ndash;30&deg;C. Myofibrillar protein functional stability was monitored by salt extractable protein (SEP) and differential scanning calorimetry (DSC). Salt extractable protein (SEP) showed that the addition of trehalose and maltose causeda smaller loss of protein solubility during the frozen storage. Peak thermal transition (T<sub>p</sub>) and denaturation enthalpy (&Delta;H) of myofibrillar proteins were evaluated. Differential scanning calorimetry (DSC) revealed a shift in the peak thermal transition temperature (T<sub>p</sub>) of myosin and actin to higher temperature as the mass fractions of trehalose and maltose increased. The transitions enthalpies of myosin and actin of the washed beef meat samples showed a higher increase with the increase of mass fraction of trehalose then of that of maltose. Since the value of denaturation enthalpy is directly related to the amount of native proteins, higher values of &Delta;H point to higher cryoprotective effects of trehalose.

scholarly journals Coconut Cryopreservation: Present Status and Future Prospects

CORD ◽  
2017 ◽  
Vol 33 (1) ◽  
pp. 21
Author(s):  
Iroshini Welewanni ◽  
Dharshani Bandupriya
Keyword(s):  
Plant Species ◽  
Medium Term ◽  
Future Directions ◽  
Factors Affecting ◽  
Cryopreservation Techniques ◽  
Long Term Preservation ◽  
Small Holder ◽  
Selection Of ◽  
Very Low Temperature

Coconut is one of the most important small holder crops worldwide. Conservation of coconut as seeds or field gene banks is not effective due to a range of limitations. Cryopreservation, which is the conservation of living propagules at very low temperature (-196ºC), is the only method available currently for the long-term conservation of germplasm for problem plant species such as recalcitrant and vegetatively propagated plant species. This review summarizes different cryopreservation techniques that have been published from 1984 until the present in relation to different coconut material; it includes a brief discussion about short and medium-term cryopreservation before describing long-term preservation. It discusses factors affecting the process and success of cryopreservation, such as selection of plant material, pre-culture of tissues, osmoprotection, dehydration, cryo-storage, thawing and post-culturing of tissues, and finally to plants. The review also describes histological and ultra-structural studies on and the use of molecular markers to assess genetic stability after cryopreservation. Limitations and future directions related to coconut cryopreservation are discussed. Additional experiments are identified that will need to be undertaken to improve our understanding of the different cryopreservation methods.

Women's Participation in Politics: Ukrainian Case

2014 ◽  
Vol 2013 (3) ◽  
pp. 53-66
Author(s):  
Skovikov Alexey
Keyword(s):  
Political Culture ◽  
Separation Of Powers ◽  
Party Competition ◽  
Political Life ◽  
Ruling Class ◽  
Political Actors ◽  
Women's Participation ◽  
Democratic Transformation ◽  
Selection Of

AbstractThe international practices takes into account the question of women's participation in the political life of modern Ukraine. The selection of the state was due to the dynamic process of democratic transformation - the separation of powers, the formation of multi-party competition among political actors in the electoral process, the activity women in the various institutions of civil society. The position was claimed on the basis of empirical data range of academic institutions and reputable sociological centers, and also interviews with experts who said that the creation of real conditions for self-realization by women's interest in politics is only possible for long term. The process is controversial and caused by political culture, traditions and interests of the ruling class represented mainly by men.

Problems of treatment of primary openangle glaucoma in combination with thrombosis of the central retinal vein

GlaucomaNews ◽  
2020 ◽  
pp. 65-69
Author(s):  
T.E. Lipatkina ◽  
◽  
Е.V. Karlova ◽  
A.V. Zolotarev ◽  
◽  
...  
Keyword(s):  
Macular Edema ◽  
Primary Open Angle Glaucoma ◽  
Antihypertensive Drugs ◽  
Open Angle Glaucoma ◽  
Vascular Wall ◽  
Open Angle ◽  
Retinal Edema ◽  
Long Term Preservation ◽  
Central Retinal Vein

Patients with primary open-angle glaucoma (POAG) and ophthalmic hypertension have an increased likelihood of developing occlusions (thrombosis) of the central retinal vein. Different groups of antihypertensive drugs differ in their mechanism of action and may affect concomitant ocular pathology, in particular, retinal edema, which occurs, for example, in occlusion of the central retinal vein. Used in most patients with glaucoma, prostaglandin analogs can contribute to the long-term preservation of macular edema due to the effect on the permeability of the vascular wall. Preparations of other pharmacological groups, reducing the production of aqueous humor, on the contrary, may contribute to its regression. Therefore, the question of choosing a drug for antihypertensive therapy in patients with primary open-angle glaucoma and concomitant macular edema is relevant and is for further study.

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