Apricot is an important fruit species in Hungary both for fresh consumption and processing. Physical parameters and change of nutrients of nine apricot cultivars were studied during the ripening period. Four Hungarian and five North-American apricot cultivars were chosen for investigation. Changes in the physical parameters were measured by three different methods (Magness-Taylor hand penetrometer, Bookfield CT3 Texture Analyser with TA 44 and TA 9 measuring head). Significant differences in flesh firmness among the cultivars were observed mainly at the beginning of ripening time. Adhesiveness, cohesiveness and chewiness of the fruits decreased continuously during ripening. The studied cultivars showed significant differences in these traits. Sugar and acid contents were also measured during ripening. The cultivars showed small differences in sugar content and bigger differences in acid content of the fruits. Our data measured and collected during this study can be useful in characterizing the apricot cultivars studied. Changes in the texture parameters responsible for transportability and the technological usability of the fruits were described across the whole ripening period. Our results may help growers as well as food technologists to determine the optimum harvest date of cultivars intended to be used for different purposes.
The increasing incidence of esophageal adenocarcinoma in the western countries has prompted us to establish the South Hungarian Regional Surveillance Group for the Study of Barrett's Esophagus in 2003. In the present report we made an interim analysis of the data collected so far. The aim of the study was to evaluate the role of acidic and biliary reflux in the development of metaplastic and dysplastic mucosal changes in patients with Barrett's esophagus.
Recent studies have shown that dehydroepiandrosterone (DHEA) administration after trauma-hemorrhage (T-H) improves cardiovascular function and decreases cytokine production in male animals. Although androstenediol, one of the metabolites of DHEA, is reported to have estrogen-like activity, it remains unknown whether androstenediol per se has any salutary effects on cytokines and cardiovascular function after T-H. To examine this effect, male Sprague-Dawley rats underwent laparotomy and were bled to and maintained at a mean arterial blood pressure of 35-40 mmHg for approximately 90 min. The animals were resuscitated with four times the volume of maximal bleedout volume in the form of Ringer lactate. Androstenediol (1 mg/kg body wt i.v.) or vehicle was administered at the end of resuscitation. Twenty-four hours after resuscitation, cardiac function and organ blood flow were measured by using (85)Sr-microspheres. Circulating levels of nitrate/nitrite and IL-6 were also determined. Cardiovascular function and organ blood flow were significantly depressed after T-H. However, these parameters were restored by androstenediol treatment. The elevated plasma IL-6 levels after T-H were also lowered by androstenediol treatment. In contrast, plasma levels of nitrate/nitrite were the highest in the androstenediol-treated T-H animals. Because androstenediol administration after T-H decreases cytokine production and improves cardiovascular function, this agent appears to be a novel and useful adjunct for restoring the depressed cardiovascular function and for cytokine production in males after adverse circulatory conditions.
Synchronously grown cultures of dark-adapted Chlorella fusca cells were illuminated with single flashes and series of flashes from a xenon discharge tube and a nitrogen laser, and the photosynthetic oxygen evolution was measured polarographically under the condition of photosynthetic saturation at ambient temperature. The mechanical and electrical construction of the Joliot-type oxygen polarograph is described. Kinetic analysis of the amperometric signal obtained after single flashes revealed that the diffusion of the oxygen molecules through the thylakoid membrane is the controlling process of the response of the electrode and leads to a lag phase at the beginning of the rise of the signal. The oscillation of the oxygen evolution produced by series of flashes is damped much more with laser flashes. This is explained in terms of the side carrier model of the losses in the oxygen production, assuming that photoactivation of the side carrier by visible light leads to less damped oscillations with xenon flashes. These experiments indirectly corroborate the validity of the side carrier model.
The probability of winter and spring frost damages experienced in peach and apricot plantations has been assessed in 5 growing regions of Hungary (Szeged-Szatymaz, around the lake Balaton, Mecsekalja, hills of Buda, Mátraalja) and (Mecsekalja, hills of Buda, PestGodo116, Duna-Tisza Mize, Matra-Bükkalja) during the period between 1951 and 2000.
Frost tolerance of flower buds on a given shoot sample is expressed by the mean value assessed after frost damage (LT50), and the meteorological records of the growing sites raised between 1951 and 2000 are used to calculate the probability of frost damage. In peach, the difference between growing sites and between varieties may become two fold as for the chance of repeated frost damage at a probability of 50 %. In apricot, the probability of frost damage may exhibit differences between growing sites up to 20 % as for susceptible varieties, and 16 % for frost tolerant varieties. Frost damage may vary between 4 and 18 % depending on the genuine frost tolerance of the varieties. Peach is afflicted by low temperature causing substantial losses of yield at the highest probability in the region Szeged-Szatymaz and at the lowest in Mátraalja. Apricot is, on the other hand, most endangered in the Duna-Tisza Mize region, while the lowest probability of frost damage is expected around Mecsek and Buda.
The critical period of frost damage in the mid of January in Szeged-Szatymaz region, in Mecsekalja the mid of February showed the highest probability of frost damage. All growing sites are frequented at high chances by frost damages occurring during and closely after the blooming period. Duna-Tisza köze is mainly afflicted in early March, whereas Mátra-Bükkalja in mid of January and each March.
The probability of temperatures below zero degree has been assessed in all the 5 regions observed. Around April 5-8 the probability of freezing temperatures diminishes steeply at all sites, whereas the risk of frost increases again around April 9— 11. That climatic peculiarity of should be taken into consideration in choosing growing sites or varieties.
Postulating the effects of a global warming up of the climate, the chances of avoiding frost damages at different growing sites by delaying the blooming dates are considered. According to our calculations, the delay of blooming by 5 days may diminish the risk of frost damage by 4-20 % at the growing sites examined, whereas a delay of 10 days reduces the risk by 37-85 % in both fruit species.
Calculations offered an answer on the question of climatic changes, whether the probability of winter and spring frosts damage changed during the 50 years. The long list of data shows the diminishing chances of winter frosts, while the probability of temperatures risking spring frost damages increased after the early 1970-es up to now.
