published_or_final_version / Medicine / Master / Doctor of Medicine

3 pp. / “Summer slump” is a decline in growth of alfalfa usually beginning in July in areas where maximum daily temperature exceeds 100 °F, such as the low elevation deserts of Southwestern U.S (Fig. 1). In more temperate regions, there is a gradual decrease in alfalfa yield in successive harvests throughout the year, but the yield decline in the summer is not as sharp as in hot summer regions. The term summer slump has also been applied to reduction in growth of perennial cool season grasses such as tall fescue during the summer.

Mūsų darbo tikslas – nustatyti skirtingų sporto šakų atstovų kai kuriuos kūno kompozicijos rodiklius bei mitybos ypatumus ir palyginti su rekomenduojamom normom. Tyrimo metu kelti uždaviniai: 1) nustatyti trumpųjų nuotolių bėgikų ir nesportuojančių (vyrų ir moterų) bei rankininkių kai kuriuos kūno kompozicijos rodiklius; 2) įvertinti trumpųjų nuotolių bėgikų ir nesportuojančių (vyrų ir moterų) bei rankininkių mitybos ypatumus; 3) palyginti tiriamųjų mitybą su rekomenduojamom normom. Tyrimo objektas - skirtingų sporto šakų atstovų kai kurie kūno kompozicijos rodikliai, bei mitybos ypatumai. Atliekant tyrimą, iškėlėme tokią problemą: šiuolaikiniame sporte didelę reikšmę turi sportininkų mityba bei kūno kompozicijos rodikliai. Tinkama mityba yra labai svarbu tiek gerai sveikatai, tiek geriems rezultatams (Andeson et al., 2000). Kiekvienas sportininkas, siekiantis sėkmingų rezultatų, turi suvokti mitybos svarbą. Gerai subalansuota, racionali dieta yra būtina maksimaliai geram pasirodymui, bet kurioje sporto šakoje (Tipton et al., 2007). Sportininkų mitybos ekspertė Eberle (2000) teigia, kad trys pagrindiniai veiksniai, lemiantys sportininko sėkmę, yra genetika, treniruotė ir mityba. Kadangi genetikos pakeisti negalime, tai privalome visą dėmesį sutelkti į tinkamo treniravimosi ir taisyklingos mitybos organizavimą, treniruotės ir mitybos suderinimą. Dauguma Lietuvos ir pasaulio elitinių sportininkų pripažįsta, kad gerai subalansuota mityba – tai 60-70 proc. sėkmės. Didelio... [toliau žr. visą tekstą] / The aim of the work is to determine some indicators of body composition and nutrition peculiarities of different sports’ athletes and to compare them with recommended values. The tasks of the work: 1) to determine some indicators of body composition of sprinters, handball players and people (men and women) who do not take any exercises; 2) to evaluate nutrition peculiarities of sprinters, handball players and people (men and women) who do not take any exercises; 3) to compare subjects’ nutrition with recommended values. The object of the research: some indicators of the body composition and nutrition peculiarities of different sports’ athletes. The problem of the research: in nowadays sport athletes’ nutrition and indicators of body composition are of great significance. Proper nutrition is very important for both health and good results (Andeson et al., 2000). Each athlete who seeks after successful results has to understand the importance of nutrition. Well balanced and rational diet is necessary for good performance in any sport (Tipton et al., 2007). The expert of athletes’ nutrition Eberle (2000) says that three main factors determining the success of an athlete are genetics, training and nutrition. As one cannot change genetics, all the attention should be concentrated on organization of proper training and regular nutrition and adjustment of training and nutrition. Most of Lithuania‘s and world elite athletes admit that well balanced nutrition forms from 60 to 70... [to full text]

Darbo tikslas - įvertinti daugiametės svidrės (Lolium perenne L.) ir nendrinio dryžučio (Phalaris arundinacea L.) drėgnio ir morfologinių dalių santykio kaitos, cheminių medžiagų (lignino, struktūrinių, nestruktūrinių angliavandenių, baltymų) kaupimosi dėsningumus augalų biomasėje ir skirtingose augalo morfologinėse dalyse priklausomai nuo augalų vystymosi tarpsnio bei vandenyje tirpių angliavandenių (VTA) koncentracijos dinamiką dienos bėgyje. / The objective of this study was to evaluate the changes in moisture content, morphological parts ratio, regularities of chemical components (protein, lignin, structural and non-structural carbohydrates) accumulation in plant biomass and different morphological parts of perennial ryegrass (Lolium perenne L.) and reed canary grass (Phalaris arundinacea L.) depending on plant development stages and to compare diurnal variation of water soluble carbohydrate (WSC) concentrations in above-ground dry matter in the two perennial grass species tested.

No description available.

This study examined the physiological and perceptual effects of carbohydrate (CHO) on variable-intensity exercise (VIE) in boys and men. It was hypothesized that CHO would increase RER in boys and men and that this increase would be greater in boys. Additionally, it was hypothesized that RPE would be attenuated by CHO. Five boys (10-12 years) and seven men (18-30 years) consumed CHO or a placebo (PL) beverage before and throughout VIE. VIE included three 12-min sets of cycling; intensity varied every 20-30 seconds between 25, 50, 75, and 125% VO2max. Boys’ post-exercise glucose was higher in the CHO trial than the PL trial and RER was lower in boys than men, but was not affected by trial. RPE increased over time but was not different between groups or trials. Though VIE responses varied between boys and men, CHO ingestion before and during VIE did not provide physiological or perceptual benefits. / School of Physical Education, Sport, and Exercise Science

In an attempt to determine the extent to which well-trained endurance athletes practice the dietary recommendations for maximizing muscle glycogen resynthesis, twenty-four collegiate cross-country runners (14 males and 10 females) were chosen as subjects. The athletes kept four-day food and activity records during both a training and competitive period in the regular season. Energy intake was shown to be adequate in both phases. Total calories from carbohydrate, primarily complex, were found to be inadequate (<60%) for male runners and desirable (>60%) for females. Approximately 50% or less of the time carbohydrate was ingested immediately post-exercise, with even far less taken in suggested quantities (-1 g CHO/kg body weight). While the male athletes consumed primarily a combined solid and liquid form of carbohydrate immediately post-exercise, the females chose solid sources. Cereals and other breads were the most popular types of carbohydrate chosen immediately following exercise, in addition to commercial sports drinks/bars which were frequently ingested. An even more unfavorable trend in the distance runners was the infrequency of additional carbohydrate being ingested at two hour intervals following exercise. There were no significant differences in dietary trends between training and competitive phases. Overall these endurance athletes were not practicing the recommended feeding regimen for optimal muscle glycogen restoration. / Department of Home Economics

The development of effective methods to cryopreserve precious cell types has had tremendous impact on regenerative and transfusion medicine. Hematopoietic stem cell (HSC) transplants from cryopreserved umbilical cord blood (UCB) have been used for regenerative medicine therapies to treat conditions including hematological cancers and immodeficiencies. Red blood cell (RBC) cryopreservation in blood banks extends RBC storage time from 42 days (for hypothermic storage) to 10 years and can overcome shortages in blood supplies from the high demand of RBC transfusions. Currently, the most commonly utilized cryoprotectants are 10% dimethyl sulfoxide (DMSO) for UCB and 40% glycerol for RBCs. DMSO is significantly toxic both to cells and patients upon its infusion. Glycerol must be removed to <1% post-thaw using complicated, time consuming and expensive deglycerolization procedures prior to transfusion to prevent intravascular hemolysis. Thus, there is an urgent need for improvements in cryopreservation processes to reduce/eliminate the use of DMSO and glycerol. Ice recrystallization during cryopreservation is a significant contributor to cellular injury and reduced cell viability. Compounds capable of inhibiting this process are thus highly desirable as novel cryoprotectants to mitigate this damage. The first compounds discovered that were ice recrystallization inhibitors were the biological antifreezes (BAs), consisting of antifreeze proteins and glycoproteins (AFPs and AFGPs). As such, BAs have been explored as potential cryoprotectants, however this has been met with limited success. The thermal hysteresis (TH)activity and ice binding capabilities associated with these compounds can facilitate cellular damage, especially at the temperatures associated with cryopreservation. Consequently, compounds that possess “custom-tailored” antifreeze activity, meaning they exhibit the potent ice recrystallization inhibition (IRI) activity without the ability to bind to ice or exhibit TH activity,are highly desirable for potential use in cryopreservation. This thesis focuses on the rational design of potent ice recrystallization inhibitors and on elucidating important key structural motifs that are essential for potent IRI activity. While particular emphasis in on the development of small molecule IRIs, exploration into structural features that influence the IRI of natural and synthetic BAs and BA analogues is also described as these are some of the most potent inhibitors known to date. Furthermore, this thesis also investigates the use of small molecule IRIs for the cryopreservation of various different cell types to ascertain their potential as novel cryoprotectants to improve upon current cryopreservation protocols, in particular those used for the long-term storage of blood and blood products. Through structure-function studies the influence of (glyco)peptide length, glycosylation and solution structure for the IRI activity of synthetic AFGPs and their analogues is described. This thesis also explores the relationship between IRI, TH and cryopreservation ability of natural AFGPs, AFPs and mutants of AFPs. While these results further demonstrated that BAs are ineffective as cryoprotectants, it revealed the potential influence of ice crystal shape and growth progression on cell survival during cryopreservation. One of the most significant results of this thesis is the discovery of alkyl- and phenolicglycosides as the first small molecule ice recrystallization inhibitors. Prior to this discovery, all reported small molecules exhibited only a weak to moderate ability to inhibit ice recrystallization. To understand how these novel small molecules inhibit this process, structure-function studies were conducted on highly IRI active molecules. These results indicated that key structural features, including the configuration of carbons bearing hydroxyl groups and the configuration of the anomeric center bearing the aglycone, are crucial for potent activity. Furthermore, studies on the phenolic-glycosides determined that the presence of specific substituents and their position on the aryl ring could result in potent activity. Moreover, these studies underscored the sensitivity of IRI activity to structural modifications as simply altering a single atom or functional group on this substituent could be detrimental for activity. Finally, various IRI active small molecules were explored for their cryopreservation potential with different cell types including a human liver cell line (HepG2), HSCs obtained from human UCB, and RBCs obtained from human peripheral blood. A number of phenolic-glycosides were found to be effective cryo-additives for RBC freezing with significantly reduced glycerol concentrations (less than 15%). This is highly significant as it could drastically decrease the deglycerolization processing times that are required when RBCs are cryopreserved with 40% glycerol. Furthermore, it demonstrates the potential for IRI active small molecules as novel cryoprotectants that can improve upon current cryopreservation protocols that are limited in terms of the commonly used cryoprotectants, DMSO and glycerol.

One of the largest problems in current medicine is the shortage of organs for transplant due to technological limitations in the storage of organs for any length of time. A possible solution to this problem would involve cryopreservation. However, current cryopreservatives such as sucrose or DMSO have concerning cytotoxic issues that limit their possible applications. A major cause of cryoinjury is the uncontrolled recrystallization of inter and intra-cellular ice crystals that occurs during the thawing process leading to mechanical damage and dehydration. The Ben lab has thus been interested in the design of compounds that are capable of inhibiting this process but do not possess other undesirable properties found in the native compounds. These synthetic analogues have been shown to increase cellular viability post-thaw. A series of mixed α/β glycopeptides are prepared and analyzed for antifreeze properties. The results of this study imply that it is not the gross conformation of the glycopeptide that is responsible for activity, but rather that intramolecular relationships may be responsible for disrupting the reorganization of ice. A technique was devised for the incorporation of triazoles into the analogues to investigate the importance of the linker and to greatly simplify the synthesis of a library of glycoconjugates. It was found that the IRI activity of glycopeptides is very sensitive to the distance between carbohydrate and peptide backbone. The electron density at the anomeric oxygen is an important parameter with respect to intramolecular networks. A series of substituted galactosides is presented that modify the electronics of the anomeric oxygen. The results demonstrate that decreasing electron density at this position appears to improve IRI activity in a predictable manner. To better understand the remarkable IRI activity of a key analogue, it was systematically truncated. This study led to the serendipitous discovery of a series of very highly IRI active analogues that do not contain a peptide backbone. These compounds represent the first non-glycopeptides that can show very significant IRI activity even at very low concentrations. The final portion of the thesis reports the efforts towards the preparation of a carbasugar analogue of AFGP-8.

Interactions between carbohydrates and proteins are increasingly being recognized as crucial in many biological processes, such as cellular adhesion and communication. In order to investigate the interactions of carbohydrates and proteins, the development of efficient analytic technologies, as well as novel strategies for the synthesis of carbohydrates, have to be explored. To date, several methods have been exploited to analyze interactions of carbohydrates and proteins, for example, biosensors, nuclear magnetic resonance (NMR); enzyme-linked immunosorbent assays (ELISA), X-ray crystallography and array technologies. This thesis describes the development of novel strategies for the synthesis of carbohydrates, as well as new efficient strategies to Quartz Crystal Microbalance- (QCM-) biosensors and carbohydrate microarrays technologies. These methodologies have been used to probe carbohydrate-lectin-interactions for a range of plant and animal lectins. / QC 20100915