Radiobiological problems in space

Summary An overview is presented on radiation problems in space, with emphasis on aspects of major interest for manned space exploration. A classification of the radiation hazards is presented and strategies for their evaluation are discussed. Space radiation problems are compared with characteristic aspects of radiation research in other disciplines, in order to provide further insight into those aspects that are unique to space.The research described in this paper was carried out while the author was a NASA VisitingThe research described in this paper was carried out while the author was a NASA VisitingThe research described in this paper was carried out while the author was a NASA VisitingThe research described in this paper was carried out while the author was a NASA Visiting     

Synthesis and Antiradical Activity of Hindered Phenol Derivatives of Flax Cellulose

Russian Journal of Bioorganic Chemistry - The modification of powdered ultradisperse cellulose by hindered phenol fragments was carried out. The modification was carried out by reacting cellulose...     

Emergency Vagotomy and Pyloroplasty for Perforated Duodenal Ulcer: Study of 73 Cases

Seventy-three unselected patients with perforated duodenal ulcer were treated by vagotomy and pyloroplasty in a six-year period. Postoperative complications were commoner when the operation was carried out after more than six hours after perforation. The follow-up results were similar to those for elective vagotomy and pyloroplasty carried out in the hospital during the past nine years.     

Cyclohexanone monooxygenase catalyzed oxidation of methyl phenyl sulfide and cyclohexanone with macromolecular NADP in a membrane reactor

Summary Methyl phenyl sulfide and cyclohexanone were oxidized to (R)- methyl phenyl sulfoxide and caprolactone by cyclohexanone monooxygenase. The reactions were carried out in a membrane reactor with the use of the macromolecular coenzyme poly (ethylene glycol)-NADP. Coenzyme regeneration was carried out with the 2-propanol/alcohol dehydrogenase system.     

Validation of a solid-phase-bound steroid scaffold for the synthesis of novel cyclic peptidosteroids.

The current article reports on the synthesis of a new type of cyclic peptidosteroid, in which a bile-acid-based scaffold was used for the conformational restriction of a loop-like peptide. Convergent coupling of two tetrapeptides to the non-peptidic steroidal entity was carried out once in the classical C-to-N and once in the non-classical N-to-C direction. Peptide backbone cyclisation was then carried out, giving rise to a ring size equivalent to approximately 12 amino acids. This type of construct will be used in the development of a peptide vaccine against measles.     

High performance liquid chromatography of phospholipids on modified silica gel

A sensitive method for the separation of phospholipids by a HPLC procedure is described. The separation was carried out on a 30 cm prepacked column with aminopropyl bonded silica under isocratic conditions. The effective separation of major phospholipid classes was carried out for less than 5 min. These chromatographic conditions were used for analysis of natural phospholipid mixtures.     

三种利用类型羊草草地氮总矿化、硝化和无机氮消耗速率的比较研究

采用同位素15N库稀释技术研究了 3种不同利用类型羊草草地土壤氮的总矿化、硝化速率以及无机氮总消耗速率 ,3种类型草地分别为 :保护区 (无人为扰动 )、割草场、过度放牧地。结果表明 :4月份过度放牧场的总矿化速率最高 ,为2 1 .3μg N/ ( g土· d) ,7月份割草场的值最高 ,为 38.5μg N/ ( g土· d) ,9月份保护区最高 ,值为 1 5 .6μg N/ ( g土· d) ,总的来看 ,保护区的总矿化速率高于其它利用类型草地 ,这与土壤有机氮的含量较高有关 ,3种类型草地铵态氮的消耗速率与总矿化速率有类似的趋势。 3种利用类型草地的氮总矿化速率均以 7月份为最高 ,分别为 36 .5、38.5、2 9.8μg N/ ( g土· d)。总硝化速率放牧场最高 ,保护区、割草场、放牧场 7月份的总硝化速率分别为 1 8.6、2 1 .4 5、35 .4 5 μg N/ ( g土·d)。 3种利用类型草地中放牧场的硝态氮含量最高 ,其消耗的速率也高于其它两种利用类型草地     

Tissue digestion for aluminum determination in experimental animal studies

Four different procedures for the determination of aluminum in tissues by atomic absorption spectrometry (AAS) were investigated. They consisted of conventional acid digestion carried out before and after sample drying, associated or not with fat extraction. Drying was carried out in a conventional oven at 65 °C for 24 h. For fat extraction, different solvents and solvent mixtures were investigated considering both extraction yield and sample adequacy for further AAS measurement. Acid digestion was carried out with pure HNO₃ or with its mixture with HClO₄. After digestion, aluminum was measured by graphite furnace atomic absorption spectrometry. Tissues were collected from Al-exposed and nonexposed mice. The results indicated that drying the sample prior to digestion is advantageous as the amount of acid necessary can be significantly reduced. This procedure does not contribute to increase the aluminum level in the samples providing that careful measures to avoid contamination are taken, as the same procedures carried out without taking any precautions to avoid contamination produced imprecise results. Finally, aluminum was not found in the fatty fraction of any sample, even in exposed mice, demonstrating that aluminum does not accumulate in this part of the tissues.     

Comparison of the antioxidant activity of aqueous and ethanolic extracts from chaga (Inonotus obliquus)

Additional extraction of biologically active compounds from a chaga shred has been carried out after completion of the aqueous extraction. The extraction was carried out using ethanol. We have shown that the antioxidant activity of the ethanolic extracts and their components is higher than that of the aqueous extracts.     

Evaluation in Drosophila melanogaster of the mutagenic potential of furfural in the mei-9a test for chromosome loss in germ-line cells and the wing spot test for mutational activity in somatic cells.

The mutagenic potential of furfural was evaluated by means of the chromosome loss test in germ cells and the wing spot test in somatic cells of Drosophila melanogaster. The chromosome loss test was carried out employing repair-proficient as well as repair-deficient females. Males carried the compound Y chromosome, BSYy+. Two routes of administration were used: injection and feeding of adult males. Genetic damage was demonstrable after matings of treated males with females carrying the excision repair-deficient mutant mei-9a. The somatic mutation and recombination test was carried out treating 72-h transheterozygous mwh+/+flr3 larvae. Acute treatment of larvae was chosen as the method of exposure. Evidence indicates that furfural induces somatic damage as measured in the wing spot test.     

Microwave assisted alkali-catalyzed transesterification of Pongamia pinnata seed oil for biodiesel production

In this study, microwave assisted transesterification of Pongamia pinnata seed oil was carried out for the production of biodiesel. The experiments were carried out using methanol and two alkali catalysts i.e., sodium hydroxide (NaOH) and potassium hydroxide (KOH). The experiments were carried out at 6:1 alcohol/oil molar ratio and 60 °C reaction temperature. The effect of catalyst concentration and reaction time on the yield and quality of biodiesel was studied. The result of the study suggested that 0.5% sodium hydroxide and 1.0% potassium hydroxide catalyst concentration were optimum for biodiesel production from P. pinnata oil under microwave heating. There was a significant reduction in reaction time for microwave induced transesterification as compared to conventional heating.     

灌水时期和灌水量对小麦氮代谢相关酶活性和籽粒蛋白质品质的影响

以高产强筋小麦品种'济麦20'为试验材料,在防雨池栽条件下研究了灌水时期和灌水量对小麦氮代谢相关酶活性和籽粒蛋白质品质的影响.结果表明,随灌水时期增多和总灌水量增加,小麦开花后旗叶硝酸还原酶活性和谷氨酰胺合成酶活性显著增高,旗叶蛋白质水解酶内肽酶(EP)、氨肽酶(AP)、羧肽酶(CP)活性降低;小麦籽粒清蛋白和球蛋白含量增加,而籽粒谷蛋白和醇溶蛋白含量、成熟期籽粒谷醇/清球比值(谷蛋白+醇溶蛋白含量/清蛋白+球蛋白含量)降低;面粉沉降值和面团稳定时间显著降低,籽粒产量显著增加.研究发现,在本试验条件下,小麦全生育期灌水3次处理(底墒水+拔节水+开花水)在灌浆前中期旗叶NR和GS活性、灌浆中后期旗叶EP、CP、AP 活性均较高,且成熟期籽粒蛋白质含量、谷醇/清球比值、面团稳定时间、籽粒产量亦较高,是获得小麦高产优质的最佳灌水处理.     

Triploidy in a fetus following amniocentesis referred for maternal serum screening test at second trimester

Amniocentesis was carried out at 17 weeks gestation in a 27-year-old woman, following an abnormal maternal serum screening (MSS) test. MSS test was carried out primarily to estimate the risk of trisomy for chromosome 21. The maternal serum markers used were alpha-fetoprotein (AFP), human chorionic gonadotrophin (hCG), and unconjugated estriol (uE3), together with maternal age. The fetus was identified as screen-positive for Edward's syndrome (trisomy 18), with low uE3, normal AFP and hCG levels. The calculated risk for trisomy 18 was more than 1:50. To identify any possible chromosomal abnormality, cytogenetic investigation was carried out on the amniotic fluid sample. The fetus's karyotype showed triploidy with 69, XXX chromosome complement in all the metaphase spreads obtained from three different cultures, using GTG banding technique. Upon termination of the fetus, gross abnormalities indicative of triploidy were present in the fetus.     

Molecular dynamics of oligopeptides 6. A comparative study of poincare cross-section of monopeptide frames in media with different hydrophobicity

A comparative study of the molecular dynamics of natural amino acid residues and their closest homologues and isomers was carried out. Molecular dynamics protocols not interfering with the principle of equidistribution of energy with respect to degrees of freedom were used. Poincare cross-sections, auto- and cross-correlation of complex exponential curves as a function of dihedrons were considered. The classification of dynamic properties of conformational degrees of freedom in the series of amino acid residues was carried out.     

A longitudinal entomologic survey on the transmission of malaria in Ouagadougou (Burkina Faso)

A longitudinal entomological malaria survey was carried out in five zones of the town of Ouagadougou, Burkina Faso, and in three neighbouring villages. The main vector is Anopheles gambiae s.l. with An. funestus having a role in some localities during the dry season. Pyrethrum spray catches were carried out once or twice per month to determine variations in vector density. Inoculation rates were estimated from the number of blood-fed vectors per man and from the sporozoite rates. Larval sampling was routinely carried out all over the urban area in order to map the larval breeding sites. Widely different degrees of malaria transmission were documented in the urban area mainly related to the spatial and temporal distribution of An. gambiae larval breeding sites. Higher inoculation rates, depending both on higher vector densities and sporozoite rates, were documented in the villages.     

Effect of transcutaneous electrostimulation on the cell composition of skin exudate

Changes were analysed in the cell composition of skin exudate induced with electrostimulation. The experiments were carried out in a group of healthy young males. In all subjects scarification of forearm skin was carried out three times at intervals of 3 days. During 12 hours after scarification the composition of cells in the exudate was studied by means of the Rebuck test. After the second and third scarification the skin was stimulated with alternating current. It was found that electrostimulation with current of individually selected parameters increased the relative number of neutrophil granulocytes in skin exudate.     

Production of proteolytic enzyme by Rhizopus oryzae in a bubble column bioreactor

Production of proteolytic enzyme in a bubble column bioreactor was carried out using the microorganism Rhizopus oryzae. Optimization of the production conditions were done adopting the EVOP (evolutionary operation technique). Studies on two variable and three variable parameters were carried out. The variable parameters were air flow rate, aeration time and incubation period. 8 hours aeration time per day, 1.66 vvm air flow rate and 2 days incubation was found to be optimum.     

Gastrointestinal parasites in goat farms from Bergamo province (Lombardy, north Italy)

A survey on gastrointestinal parasites in goat farms in Bergamo province was carried out from May 2005 to January 2006. Thirty-one dairy goat farms and 836 adult female goats were examined. Faecal sampling was carried out before the antihelminthic treatments, and the sampling times were grouped in three seasonal periods (June-August, September-October and November-March). Faecal exams were carried out by a McMaster method and eggs per gram (EPG) were calculated for each gastrointestinal parasite. Differences in prevalence of Strongylida, Trichuris and Nematodirus were found between farms with goats on pasture and those where animals were permanently housed indoor. Strongyloides spp. showed higher values of prevalence in goats housed indoor. With regard to the sampling seasons, Strongylida eggs were more prevalent in summer while Nematodirus in winter in goats at pasture. Strongyloides occurred more frequently in autumn in stabled goats.     

Exploring the genome of Trypanosoma vivax through GSS and in silico comparative analysis

A survey of the Trypanosoma vivax genome was carried out by the genome sequence survey (GSS) approach resulting in 1,086 genomic sequences. A total of 455 high-quality GSS sequences were generated, consisting of 331 non-redundant sequences distributed in 264 singlets and 67 clusters in a total of 135.5 Kb of the T. vivax genome. The estimation of the overall G+C content, and the prediction of the presence of ORFs and putative genes were carried out using the Glimmer and Jemboss packages. Analysis of the obtained sequences was carried out by BLAST programs against 12 different databases and also using the Conserved Domain Database, InterProScan, and tRNAscan-SE. Along with the existing 23 T. vivax entries in the GenBank, the 32 putative genes predicted and the 331 non-redundant GSS sequences reported herein represent new potential markers for the development of PCRbased assays for specific diagnosis and typing of Trypanosoma vivax.     

二十年来天目山鸟类群落结构变化趋势的初步分析

研究鸟类群落结构的变化既有理论意义,也有实践价值。大多数的鸟是食虫的或杂食的,纯粹素食者较少。实际上在自然生态系统中,能量进入鸟类已经经过几道营养层(trop-hiclevel),在能量金字塔中,鸟类往往处于较上层。因此,鸟对环境条件的恶化,常能在较短时期内立即感受到,并迅速影响其生存。由于鸟类对自然生态平衡及环境保护质量能