Rhombomere rotation reveals that multiple mechanisms contribute to the segmental pattern of hindbrain neural crest migration

Hindbrain neural crest cells adjacent to rhombomeres 2 (r2), r4 and r6 migrate in a segmental pattern, toward the first, second and third branchial arches, respectively. Although all rhombomeres generate neural crest cells, those arising from r3 and r5 deviate rostrally and caudally (J. Sechrist, G. Serbedzija, T. Scherson, S. Fraser and M. Bronner-Fraser (1993) Development 118, 691–703). We have altered the rostrocaudal positions of the cranial neural tube, adjacent ectoderm/mesoderm or presumptive otic vesicle to examine tissue influences on this segmental migratory pattern. After neural tube rotation, labeled neural crest cells follow pathways generally appropriate for their new position after grafting. For example, when r3 and r4 were transposed, labeled r3 cells migrated laterally to the second branchial arch whereas labeled r4 cells primarily deviated caudally toward the second arch, with some cells moving rostrally toward the first. In contrast to r4 neural crest cells, transposed r3 cells leave the neural tube surface in a polarized manner, near the r3/4 border. Surprisingly, some labeled neural crest cells moved directionally toward small ectopic otic vesicles that often formed in the ectoderm adjacent to grafted r4. Similarly, they moved toward grafted or displaced otic vesicles. In contrast, surgical manipulation of the mesoderm adjacent to r3 and r4 had no apparent effects. Our results offer evidence that neural crest cells migrate directionally toward the otic vesicle, either by selective attraction or pathway-derived cues

Cellular senescence in the ageing brain:to eliminate or not to eliminate?

Senescent cells are damaged cells that no longer divide. They are present in aged human and mouse tissues. Here, they secrete pro-inflammatory molecules and promote various age-related dysfunctions and pathology. Removal of senescent cells however improves health span. Because it remains poorly understood how cellular senescence develops in the ageing brain, the goal of the research in this thesis was to gain more insight into brain senescence. The information hereby gained can help to develop therapeutic approaches aimed at preserving brain functions for a prolonged period of time. In chapter 1, an introduction to senescent cells in the brain is given. In chapter 2, the effect of the modulation of lysosomes, organelles that degrade damaged particles, in senescent cells was investigated. In chapter 3, single-cell gene expression profiling was used to identify distinct, age-dependent p16 expressing cell populations in the mouse brain. In chapter 4, the direct and indirect effect of genotoxic stress-induced senescence on glial cells in culture and in mice were characterized. In chapter 5, the data presented in chapters 2-4 are summarized, and future prospects in the area of basic and translational biology are discussed. In conclusion, the work presented here helps to elucidate the role of senescent cells and represents an important pillar for the characterization and targeting of brain senescence

Osuuskunta- ja osuustoiminnan edistäminen Suomessa

Opinnäytetyömme tavoitteena oli tutkia osuuskunta- ja osuustoimintaa Suomessa ja etsiä keinoja sen edistämiseen. EU-rahoitteinen Conventus-projekti toimii opinnäyt-teemme hankkeistajana. Teimme kaksi erillistä kyselytutkimusta, joiden tarkoituksena oli selvittää, kuinka osuuskunta- ja osuustoimintaa voitaisiin edistää Suomessa. Tutkimus toteutettiin sekä kvantitatiivisesti että kvalitatiivisesti. Teoreettinen viite-kehys muodostui kirjallisesta tutkimusaineistosta liittyen osuustoimintaan ja osuus-toiminnan arvoihin sekä periaatteisiin. Tiedonkeruumenetelmänä käytimme kahta erillistä sähköpostikyselyä. Sähköpostikysely lähetettiin 37 osuuskuntayrittäjälle ja toinen erillinen sähköposti-kysely lähetettiin 11 osuustoimintaa tukevalle henkilölle. Kyselyt laadittiin ja toteu-tettiin Datan analysointi- ja kyselytyökalu Webropolin avulla. Osuuskuntayrittäjien kyselyyn saimme 14 vastausta ja osuustoimintaa tukevien henkilöiden kyselyyn 5 vastausta. Kyselyiden tuloksia ja teoriataustaa vertaillessa huomasimme, että osuus-kuntien alkuperäinen tarkoitus eli yleinen hyvinvointi ja hyväntekeväisyys, on väis-tymässä tavallisen yrittämisen ja voitontavoittelun edeltä.The aim of our thesis was to investigate the cooperatives in Finland and to find ways to promote them. The EU-funded project Conventus is the assignor of our thesis work. We made two separate surveys, which were designed to determine how coop-eratives could be promoted in Finland. The research for our thesis was conducted both quantitatively and qualitatively. The questionnaires contained primarily open questions to enable use to find in-depth an-swers and information. The theoretical frame of reference consists of written research materials related to the cooperative movement and cooperative values and principles of operation. We used two separate e-mail surveys as a data collection method. One e-mail survey was sent to 37 co-operative entrepreneurs and another separate e-mail survey was sent to 11 supporters of cooperatives. The questionnaires of these surveys were drawn up, and were carried out with the data analysis and query tool Webropol. We received 14 answers from the cooperative enterprises and 5 replies from the supporters of cooperatives. After receiving the responses to our question-naires we compared them to the theoretical background of our thesis and found out that the original ideology of cooperatives, the welfare of members, has been forgot-ten and it has been replaced with normal business standards, making profit

Cumulative rainfall collectors – A tool for assessing groundwater recharge

The great majority of Southern African aquifers depend on rainfall for their recharge. The accurate estimation of recharge remains one of the biggest challenges for groundwater investigators. Accurate recharge estimations are needed for proper groundwater management as this governs the estimation of sustainable exploitation. Current estimates of recharge to aquifers range between 0.2 and 3% of annual rainfall for the drier Karoo and Kalahari areas and up to 20% for the winter rainfall region of the Western Cape. Important input for determining recharge is knowledge of the chemical and isotopic composition of rainfall. This paper describes a simple, low-cost and low-maintenance tool, the cumulative rainfall collector (CRC), which provides a cumulative sample of rainfall which is unaffected by evaporation. The instrument is capable of collecting rainfall over periods of up to one year. The crucial aspect is to store sufficient rainfall, to eliminate evaporation by covering the water sample with silicon oil and to reduce interference by birds. CRCs were installed at Struisbaai, the West Coast and the South Coast of the Western Cape Province. CRC data for Struisbaai indicate that recharge to the Table Mountain Group (TMG) Aquifer is 17.4% of mean annual rainfall. The West Coast transect includes two production wellfields. CRC data indicate that recharge is 9.7% to 13.5% for the Bredasdorp Formation of the Langebaan Road Wellfield. At Agter Witzenberg recharge estimations range from 24% to 46% to the Nardouw Formation of the TMG. The South Coast transect encompasses the Klein Karoo Rural Water Supply Scheme and CRC data indicate that recharge to the Peninsula Formation of the TMG is 5%. Water SA Vol.31 (3) 2005: pp.283-29

Towards a Neuroscience of Mind-Wandering

Mind-wandering (MW) is among the most robust and permanent expressions of human conscious awareness, classically regarded by philosophers, clinicians, and scientists as a core element of an intact sense of self. Nevertheless, the scientific exploration of MW poses unique challenges; MW is by nature a spontaneous, off task, internal mental process which is often unaware and usually difficult to control, document or replicate. Consequently, there is a lack of accepted modus operandi for exploring MW in a laboratory setup, leading to a relatively small amount of studies regarding the neural basis of MW. In order to facilitate scientific examination of MW the current review categorizes recent literature into five suggested strategies. Each strategy represents a different methodology of MW research within functional neuroimaging paradigms. Particular attention is paid to resting-state brain activity and to the “default-mode” network. Since the default network is known to exert high activity levels during off-task conditions, it stands out as a compelling candidate for a neuro-biological account of mind-wandering, in itself a rest-based phenomenon. By summarizing the results within and across strategies we suggest further insights into the neural basis and adaptive value of MW, a truly intriguing and unique human experience

Aplikasi Penggunaan Tepung Porang (Konjac Glucomannan) Sebagai Stabilizer Yogurt yang Ditambahkan Sari Buah Nanas

Yogurt merupakan makanan fungsional karena mengandung fiber dan bakteri asam laktat yang merupakan probiotik. Yogurt yang ada di pasaran seringkali hanya mengandung perisai sintesis, sehingga penambahan ekstrak dari buah seperti nanas akan menambah citarasa selain kandungan antioksidan yang tinggi. Masalah dari yogurt ketika ditambah sari nanas yaitu sineresis yaitu terjadi pemisahan sehingga dibutuhkan stabilizer. Konjac glucomannan yaitu karbohidrat komplek yang berasal dari umbi porang yang berfungsi sebagai pengental dalam makanan yang juga dapat digunakan sebagai food stabilizer. Tujuan penelitian ini adalah mengkaji aplikasi penggunakan konjac glucomannan pada kadar 1%, 2,5% dan 5% pada yogurt yang ditambah sari nanas pada konsentrasi  0%, 2,5% dan 5%. Respon yang dikaji adalah karakter fisik (viskositas, dan stabilitas), karakter kimia (pH, dan total phenolic content), aktifitas antioksidan yang diukur menggunakan metode aktifitas radikal bebas DPPH dan Ferri Reduction Antioxidant Power (FRAP) serta uji sensori menggunakan hedonic scale. Hasil menunjukkan bahwa konjac glucomannan 5% dapat menstabilkan yogurt yang ditambah sari nanas hingga 5%, sedangkan penambahan konjac 2,5%  dapat menstabilkan yogurt  yang mengandung sari nanas hingga 2.5% dan penambahan 1% konjac tidak dapat menstabilkan yogurt yang ditambah ekstrak nanas. Pada penambahan konjac 5% dan ekstrak nanas 5% menghasilkan yoghurt yang mempunyai aktivitas antioksidan yang paling tinggi pada metode FRAP. Akan tetapi, hasil uji orgonaleptic sampel ini menunjukkan kurang disukai dibandingkan dengan yoghurt tanpa penambahan sari buah nanas karena rasanya lebih pahit

Low temperature curing by using zinc-2-mercaptobenzothiazole (ZMBT) in combination with dithiocarbamates (DTC) and amine curing systems

Studies have been done to explore possibilities of low temperature curing in typical natural rubber based compounds. Combination of fast accelerators together with amine activation has been used in this approach. It has been found that it is possible to lower the vulcanization temperature as low as 60 °C and still obtain sufficient cure. The combination of ZMBT/ZDC/Amine provides a best compromise with regard to cure kinetics and ultimate properties. In consideration with N-Nitrosamine safe system, the combination of ZBEC/ZMBT/DPG provides an optimum solution. A three variable experimental design was executed to optimize the recipe comprising of ZBEC/ZMBT/DPG systems

Identification of sources and infiltration regimes of nitrate in the semi-arid Kalahari: Regional differences and implications for groundwater management

The Kalahari region of southern Africa offers much potential for nitrogen input into its groundwater. High nitrate concentrations in Kalahari groundwater are therefore quite common and are caused by both anthropogenic and natural sources. Forecasting groundwater nitrate concentrations remains challenging. Source identification of nitrate contamination in groundwater is an important first step for groundwater management and quality prediction, and is aided by isotope analysisof nitrate in the water. Comparative data from 3 groundwater study sites in the Kalahari of Botswana and Namibia with widely different characteristics are presented. Two of the sites (Ghanzi and Gobabis) have shallow water tables in fractured quartzite. These aquifers were affected by pollution from cattle wastes (manure) and septic tank outflows resulting in groundwater nitrate levels exceeding 1 000 mg NO3/. and in ƒÂ15N values of between +7 and +20 ñ AIR. Short-term increases of groundwater nitrate concentrations were triggered by exceptional rainfall events occurring every 10-20 years. At the third site (Serowe in Botswana) there is similar land use and land cover, yet the aquifers are deeper, groundwater dates to Late-Pleistocene age and borehole levels do not show a response to present-day high-rainfall episodes. Nitrate levels up to 219 mg/. are found, but lower 15N content (ƒÂ15N of +3 to +8 ñ) indicates a natural origin of the nitrate. In this area pollution nitrate is sufficiently delayed in the vadose zone, reaching the saturated zone much later. The data from all 3 sites suggest that nitrogen management options can only be evaluated once an understanding of sources, processes and flowpatterns has been established

Differentiation-associated changes of cation-transport activities in myeloid leukemic cell lines

AbstractInduction of differentiation in HL-60 and U-937 leukemic cell lines, resulted in 1.5–10-fold increase in 45Ca2+ uptake. The increased 45Ca2+ uptake in the differentiating cells was inhibited by verapamil, cromolyn and amiloride. Elevation in Ca2+ uptake in differentiating cells was also demonstrated using the fluorescent probe, fura-2 acetoxymethyl ester. The increased 45Ca2+ uptake was accompanied by a decrease in ouabain-insensitive and -sensitive 86Rb+ uptake. Furthermore, correlation between the changes in these activities was observed. Modulation of extracellular pH affected differentiation: higher pH increased the extent of differentiation