The convergence of synthetic organic and polymer chemistries

Several recent conceptual advances, which take advantage of the design criteria and practical techniques of molecular-level control in organic chemistry, allow preparation of well-defined polymers and nanostructured materials. Two trends are clear: the realization that synthesis of complex macromolecules poses major challenges and opportunities and the expectation that such materials will exhibit distinctive properties and functions. Polymer synthesis methods now being developed will yield well-defined synthetic macromolecules that are capable of mimicking many of the features of proteins (for example, three-dimensional folded structure) and other natural materials. These macromolecules have far-reaching potential for the study of molecular-level behavior at interfaces, in thin films, and in solution, while also enabling the development of encapsulation, drug-delivery, and nanoscale-patterning technologies.     

Bilateral hydronephrosis secondary to endometriosis managed by endoscopic ureteral stent placement in a captive Guinea baboon (Papio papio)

Spontaneous endometriosis is an estrogen-dependent, progressive and painful disease that affects a variety of nonhuman primates, including several species of baboons (Papio sp.). This case documents multimodal management of severe endometriosis in a captive female baboon within a zoological institution. An 18-yr-old, intact female Guinea baboon (Papio papio) was found to have an enlarged uterus. Fifteen months post ovariohysterctomy, scarring associated with endometrial tissue resulted in ureteral strictures, bilateral hydronephrosis, and azotemia. Cystoscopic placement of bilateral ureteral stents with fluoroscopy was performed and resulted in short-term clinical improvement. The animal's condition declined and euthanasia was elected 4 mo after ureteral stent placement. Severe endometriosis with secondary inflammation resulting in bilateral hydroureter and hydronephrosis, as well as concurrent cystitis, ureteritis, and pyelonephritis were confirmed at necropsy. Despite possible complications, ureteral stents can be considered a useful therapeutic option in patients with ureteral disease.     

Evaluation of hematology and serum biochemistry of cold-stunned green sea turtles (Chelonia mydas) in North Carolina, U.S.A

Hypothermia or cold-stunning is a condition in which the body temperature of an animal decreases below normal physiologic range and which has been linked to severe morbidity in sea turtles. Reports have focused on the physiologic changes caused by cold-stunning in Kemp's Ridley sea turtles (Lepidochelys kempii) and loggerhead sea turtles (Caretta caretta), but few have evaluated the green sea turtle (Chelonia mydas). This study evaluated hematologic and serum biochemical profiles of cold-stunned green sea turtles in North Carolina, USA. When compared with healthy, free-ranging juvenile green turtles from the same region, cold-stunned turtles exhibited hypoglycemia, hypocalcemia (both total and ionized calcium), hyponatremia, hypokalemia, hypoproteinemia, hypoalbuminemia, hyperphosphatemia, and elevations in uric acid and blood urea nitrogen. These findings contrast with some previously reported changes in cold-stunned Kemp's Ridley and loggerhead sea turtles. These results emphasize the importance of basing therapeutic regimens on biochemical analyses in cold-stunned sea turtles.     

The influence of basic aerosols on throughfall fluxes of sulfate,ammonium and nitrate in three oak stands along a distance gradient from a lime quarry

Three oak stands (Quercus petraea and Quercus robur) in the Weinviertel, Lower Austria, located along a distance gradient from a lime quarry, were studied to determine the effects of basic aerosols on the deposition of ammonium, nitrate and sulfate. Higher concentrations of limestone aerosols in the vicinity of the quarry are suggested by higher Ca²⁺ fluxes and pH in throughfall and precipitation. The ammonium/nitrate ratio in throughfall decreases with distance from the quarry, though monitoring of NH₃ and NO₂ concentrations in the air with passive samplers shows the opposite trend. These findings support the theory of discrimination against NH₃ in dry deposition due to the presence of Ca ²⁺ particles on leaf surfaces resulting from limestone aerosols. Higher sulfate deposition near the quarry is consistent with higher atmospheric SO₂ concentrations and co-deposition between calcium and sulfate.     

Biologically important thiols in various vegetables and fruits

Biological thiols are important antioxidants, and recent studies showed that their contents vary depending on the groups of foodstuffs. Therefore, we investigated the levels of some biological thiols in various vegetables and fruits by using a sensitive high-performance liquid chromatography (HPLC) technique. Biological thiols measured in some vegetables and fruits include glutathione (L-glutamyl-L-cysteinly glycine, GSH), N-acetylcysteine (NAC), captopril [CAP (C9H15NO3S)], homocysteine (HCYS), cysteine (CYS), and gamma-glutamyl cysteine (GGC). Our results show that biological thiol contents are between 3-349 nM/g wet weight in vegetables and 4-136 nM/g wet weight in fruits. CAP is only found in asparagus (28 nM/g wet weight). Furthermore, none of the biological thiols analyzed were found in cabbages, red grapes, blackberries, apples, and peaches. Therefore, various vegetables and fruits differ significantly in their thiol contents. Oxidation of these important thiols may occur and result in the production of toxic byproducts, if they are exposed to radiation and ozone treatment for sterilization purposes. Further studies should be performed to monitor the levels of these biological thiols.     

Public perceptions of natural disturbance in Canada’s national parks: The case of the mountain pine beetle (Dendroctonus ponderosae Hopkins)

Since the 1990s, the mountain pine beetle (MPB) population has exploded in western Canada. In national parks, MPB has the potential to impact visual quality and safety of visitors, and to spread beyond park boundaries to the industrial forest landbase. Control measures have been initiated in some parks to lessen these impacts. A study was undertaken to examine public attitudes, knowledge, issue salience, and management preferences for MPB in Banff and Kootenay national parks. Data were collected by mail survey in 2003 from 1385 residents living in or near the parks. MPB was an important issue for the majority of respondents and they had low knowledge of MPB, expressed negative attitudes towards it, and supported measures to control it. Preferred control measures included those directed at the current infestation. Proactive approaches in uninfested forests were generally not supported. Issue salience and knowledge were the best predictors of attitudes toward the MPB. Attitudes were the best predictors of support for no intervention in beetle infestations in national parks. Management implications include the lack of knowledge and support for natural disturbance and ecological integrity policies in national parks.     

The nearest-plant method is robust and powerful enough for different survey teams to monitor change in mesic grassland species composition

A long-term rangeland monitoring programme needs to employ a field survey technique that is practicable, precise, powerful enough to distinguish change, not prone to worker bias, and able to distinguish real change from operator error arising from staff turnover. These criteria were used to evaluate a widely used grassland sampling technique in South Africa – the nearest-plant (with 200 points) method (NP) – against common alternatives, namely NP excluding forbs (NP-nf), the plant number scale (PNS; a cover-abundance method) and quadrat frequency (QF), using multivariate ordination and permutation tests. Four trained teams surveyed four grasslands using each method. PNS took more than twice as long as the other techniques, which were similarly rapid. Estimates of composition using NP methods were the most precise and PNS was least repeatable, with QF intermediate. Compositional differences between sites were most finely distinguished using NP-nf, followed by NP and QF. PNS was able to detect only marked differences and had the greatest potential for surveyor bias. The NP method, with or without including forbs, is therefore recommended for monitoring the species composition of mesic, dense grassland. Some suggestions for monitoring agencies on how best to use multivariate methods are presented.