Synthesis of Novel Thin-Film Materials by Pulsed Laser Deposition

Pulsed laser deposition (PLD) is a conceptually and experimentally simple yet highly versatile tool for thin-film and multilayer research. Its advantages for the film growth of oxides and other chemically complex materials include stoichiometric transfer, growth from an energetic beam, reactive deposition, and inherent simplicity for the growth of multilayered structures. With the use of PLD, artificially layered materials and metastable phases have been created and their properties varied by control of the layer thicknesses. In situ monitoring techniques have provided information about the role of energetic species in the formation of ultrahard phases and in the doping of semiconductors. Cluster-assembled nanocrystalline and composite films offer opportunities to control and produce new combinations of properties with PLD.     

Arthropod assemblages in vegetative vs. humic portions of epiphyte mats in a neotropical cloud forest

Epiphyte mats (contiguous pieces of live and dead epiphytes perched upon branches of trees) are a conspicuous component of tropical cloud forests and harbor diverse meso- and microarthropod communities. We investigated differences in arthropod assemblage structure between the vegetative (green) and humic (brown) portions of epiphyte mats in a lower montane forest in Monteverde, Costa Rica. Because of qualitative differences between the two substrates, we hypothesized that they would support different arthropod communities and that variation in community parameters would be linked to the quantity of brown material present in a mat sample. The green fraction contained twice as many individuals and species per gram dry mass than the brown fraction. Morphospecies composition was very similar between green and brown portions, but the relative abundance of several taxa differed significantly between the substrates. Contrary to our prediction, total arthropod abundance and richness in a sample were not correlated with the proportion of brown material present. In laboratory trials, the most common morphospecies of oribatid mite in this system showed a preference for brown substrates.     

Ovariectomy as treatment for ovarian bacterial granulomas in a Duvaucel's gecko (Hoplodactylus duvaucelii)

CASE HISTORY: An adult female Duvaucel's gecko (Hoplodactylus duvaucelii) from a threatened species breeding programme presented due to a prolonged gestation period and distended abdomen.

CLINICAL AND PATHOLOGICAL FINDINGS: The gecko was in lean body condition with an irregularly shaped, firm mass in the coelomic cavity. Radiographically there was a diffuse radio-opacity within the coelomic cavity with cranial displacement of the right lung field. Ultrasonography revealed a round homogenous abdominal mass of medium echogenicity with an echogenic capsule. Haematology showed a leucocytosis with a moderate left shift in heterophils and toxic changes. Bilateral ovariectomy was performed to remove two ovarian granulomas and Salmonella enterica subspecies houtenae (IV) was cultured from the ovarian tissue. The gecko recovered well from the surgery, regained weight and remained in good health 3 years following the surgery.

DIAGNOSIS: Pre-ovulatory stasis and ovarian granulomas associated with infection with Salmonella enterica subsp. houtenae.

CLINICAL RELEVANCE: The surgery described in this case resulted in recovery of the gecko, which despite its loss of reproductive capability is of value as an education animal. This is the first report of pre-ovulatory stasis and ovarian granulomas associated with infection with Salmonella enterica in a Duvaucel's gecko and is also the first reported case of pre-ovulatory stasis in a viviparous lizard species. The case adds to knowledge regarding potential reproductive pathology in lizards, which is particularly important information for managers of captive lizard breeding programmes.     

Early Pregnancy Diagnosis by Serum Progesterone and Ultrasound in Sheep Carrying Somatic Cell Nuclear Transfer-Derived Pregnancies

Early pregnancy diagnosis and monitoring play an important role following embryo transfer in sheep. The aims of the current study were to investigate (i) the pattern of serum progesterone profiles in sheep carrying somatic cell nuclear transfer (SCNT)‐derived (clone) pregnancies, and (ii) the frequency of pregnancy loss during development following SCNT embryo transfer. Sheep SCNT embryos were made using standard nuclear transfer techniques. Day 7 embryos were surgically transferred to oestrus‐synchronized recipients (n = 27). As a control, normal fertile ewes (n = 12) were bred by natural breeding. Serum was collected from all the ewes on the day of estrus (day 0 sample), 7 days post‐estrus (day 7 sample) and 19 days post‐estrus (day 19 sample) and every 10 days thereafter until lambing or pregnancy loss occurred. Serum progesterone (P4) was assessed using enzyme immunoassay. Pregnancy was confirmed by ultrasound scanning on day 35 of pregnancy followed by subsequent scanning every 10 days. In control ewes, pregnancy rate on day 35 was 83.3% (10/12), whereas in the ewes that received SCNT embryos, it was 22.2% (6/27; p < 0.05). The day 45 pregnancy rate in the control ewes was 83.3%, whereas in the SCNT embryo recipients it was 11.0% (p < 0.05). Hormone analysis revealed that SCNT embryo recipients exhibited a significantly lower P4 profiles at different time points in pregnancy compared to controls (p < 0.05). This study highlights the use of serum progesterone in combination with ultrasound for the investigation of embryo loss and crucial times during development of normal and SCNT embryos in sheep. Further, the serum P4 levels directly reflect the degree of placental development in these two groups.     

Growth measurements of saprotrophic fungi and bacteria reveal differences between canopy and forest floor soils

Canopy-held organic matter develops into a distinct soil system separate from the forest floor in wet temperate coniferous forests, creating a natural microcosm. We distinguished between fungal and bacterial components of the decomposer community in one site with Maple (Acer macrophyllum) and one site with Alder (Alnus rubra) by using direct measurements of growth; acetate incorporation into ergosterol, and leucine incorporation for fungi and bacteria, respectively. The higher organic matter content of the canopy soils correlated with higher fungal growth. The relative importance of fungi, indicated by fungal:bacterial growth ratio, was higher in the canopy soil of the Maple site, while there was no difference in the Alder site. The high C:N ratio of the Maple canopy soil likely contributed to this difference. These results demonstrate a divergence between canopy and forest floor that should be explored to gain insights in decomposer ecology using the natural microcosms that the canopy soils provide.     

Phytoplankton community structure and the drawdown of nutrients and CO2 in the southern ocean

Data from recent oceanographic cruises show that phytoplankton community structure in the Ross Sea is related to mixed layer depth. Diatoms dominate in highly stratified waters, whereas Phaeocystis antarctica assemblages dominate where waters are more deeply mixed. The drawdown of both carbon dioxide (CO2) and nitrate per mole of phosphate and the rate of new production by diatoms are much lower than that measured for P. antarctica. Consequently, the capacity of the biological community to draw down atmospheric CO2 and transport it to the deep ocean could diminish dramatically if predicted increases in upper ocean stratification due to climate warming should occur.