Zugl.: Giessen, Universiẗat, Diss., 2007.

Regensburg, Univ., Diss., 2007

Zugl.: Freiburg (Breisgau), Univ., Diss., 2009

Thesis (Ph. D.)--University of Rhode Island, 2004. / Typescript. Includes bibliographical references (leaves 119-123).

Thesis (Ph. D.)--University of Chicago, Dept. of Pharmacological and Physiological Sciences, August 1999. / Includes bibliographical references. Also available on the Internet.

Mainz, Univ., Diss., 2001.

Abstract In dim light, reliable coding of visual information becomes compromised, unless the sensitivity of the visual system to light is improved by structural and functional adaptations. Thus far, many adaptations for night vision in the compound eyes of nocturnal insects have been described, but little is known about the mechanisms underlying the electrochemical signalling in their photoreceptors. In this thesis, whole-cell patch-clamp and mathematical modelling are utilised to study basic electrical properties and ionic currents in photoreceptors of two nocturnal insects, the American cockroach Periplaneta americana and the field cricket Gryllus bimaculatus. Photoreceptors in both species showed large input resistance, membrane capacitance and phototransduction gain (large single photon responses) compared with most studied diurnal insects, providing improved sensitivity to light. The photoreceptors also expressed two voltage-sensitive outward currents: a transient current and a sustained current. The cricket photoreceptor expressed a dominating transient current, which is a typical characteristic for insects adapted for slow vision in dim light. By contrast, in the majority of cockroach photoreceptors the sustained current dominated, which is more common among fast diurnal species. Model simulations indicated that the sustained current is necessary for improved photoreceptor dynamics. Examination of light-induced currents suggested that the functional variability in cockroach photoreceptors is in part derived from variations in the total area of the photosensitive membrane. Recordings of light-induced currents also revealed that the cockroach light-gated channels are only moderately Ca2+-selective and that the polarisation-sensitive photoreceptors of the cricket may utilise phototransduction machinery in some details different from that in regular photoreceptors. Furthermore, the dynamics and information transfer rates of polarisation-sensitive photoreceptors in the cricket were clearly inferior to their regular counterparts, suggesting that they are not necessary for image formation.

Abstract The polycystic ovary syndrome, described first as the association of bilateral polycystic ovaries and amenorrhoea, oligomenorrhoea, hirsutism and obesity, was later shown to be a complex metabolic syndrome. The first purpose of this study was to investigate the occurrence of hyperinsulinaemia and the severity of insulin resistance and glucose tolerance disorders in polycystic ovary syndrome by means of the oral glucose tolerance test and the euglycaemic hyperinsulinaemic clamp. The next goal was to investigate whether women with polycystic ovary syndrome would benefit from insulin-sensitising drugs, and in particular to compare the effects of metformin and a contraceptive pill containing ethinyl oestradiol and cyproterone acetate. Altogether, 81 women with polycystic ovary syndrome and 34 healthy control subjects were involved in the study. Marked impairment of insulin sensitivity in obese subjects with polycystic ovary syndrome, including a decrease of both cellular oxidative and non-oxidative utilisation of glucose, and a slight non-significant decrease of insulin sensitivity in non-obese subjects was observed. Both non-obese and obese subjects with polycystic ovary syndrome exhibited increased abdominal obesity compared with the controls, confirming the fact that obesity, in particular abdominal obesity, is an important contributor in the development of insulin resistance in this syndrome. Metformin alleviated hyperandrogenism by essentially decreasing ovarian, but not adrenal androgen secretion. The improvement of hyperandrogenism and ovarian function seemed to be mediated by the improvement of hyperinsulinaemia, which resulted itself from subtle improvements in both hepatic insulin extraction and insulin sensitivity. Metformin decreased abdominal obesity and the release of free fatty acids from adipose tissue, and improved ovarian cyclicity and fertility. The transient decrease in serum leptin levels observed may have some role in the improvement of ovarian function. The contraceptive pill significantly improved hyperandrogenism and hirsutism, and it slightly affected glucose metabolism. Thus, it could be the treatment of choice in women with hirsutism problems and no fertility hopes. Metformin could be the drug of choice for women with polycystic ovary syndrome who wish to conceive. Because of its beneficial metabolic effects, the value of metformin in reducing the risk of cardiovascular diseases in polycystic ovary syndrome needs to be further studied.

ABSTRACT Carton Clamp Test Methodologies and the Effects on Load Containment and Retention Tyler Don Blumer A carton clamp is an alternative device for moving packages and material. Instead of using iron tines like that of a conventional forklift, a carton clamp uses two large aluminum platens to slightly compress and secure the load for handling. This is advantageous as it allows operators to move layers of a unitized load individually, and eliminates the need for a pallet when handling full unitized loads. When using a carton clamp attachment, it is often difficult for operators to accurately gauge the amount of force being applied to the load. The required clamping force changes depending on the size, shape, and weight of the load. This creates the potential for under-clamping (slippage) and over-clamping (compressive damage). Seeing a market need for a reliable means of testing, two organizations set out to develop a testing protocol. A rift formed between schools of thought regarding the correct testing procedure. ISTA provides a sterile, calculated, and stationary simulation of carton clamp handling in its ISTA 6-SAMS test protocol. ASTM offers a more holistic, dynamic, observational approach in its mobile ASTM 6055 standard protocol. One school of thought is suggested to imply that a package should be developed to be handled by the carton clamp (ASTM). The other school of thought is that the carton clamp attachment should be properly adjusted to the package specimen (ISTA). Previous studies have been performed citing the ISTA standard and using a specialized carton clamping device vibration device that is calibrated for laboratory research. Arguably, this method, though repeatable in nature, does not accurately simulate carton clamp handling found in industry. Likewise, the equipment investment is cost prohibitive for those in industry wishing to duplicate such a study. ASTM uses a carton clamp truck as used in industry, but does not specify any specific parameters making repeatability between laboratories and practitioners ambiguous. This study examined whether or not a common ground can be reached; implementing a carton clamp lift truck as found in industry allowing for mobile (hazard course) testing. A modified version of ISTA 3B will be paired off against ASTM 6055 for evaluating both column and cross stack pallet patterns with a variety of treatments. This study attempted to determine if carton clamps as found in industry are capable and repeatable enough to provide consistent data. Similarly, this study examined the test methodologies effect on load containment via stretch film force, load retention via unitized load slippage, and the effects of ride height and driver interaction. The study sought to understand if these effects are uniform across the unitized load, or if particular layers of the load more affected than others.

The relationship between leaf physiognomy and precipitation has been explored worldwide in regions under different climate conditions. Unlike the linear relationship established between the percentage of woody dicot species with entire margins and mean annual temperature, precipitation has been reported to correlate to different leaf physiognomic characters depending on the region where the correlation is studied. To investigate if precipitation can be calculated from leaf physiognomic characters on the basis of regional sample sites, data from 50 mesic to humid forests in China were analyzed in this study. With data from Chinese forests, the leaf-area analysis based on linear regression between natural logarithms of leaf size and mean annual precipitation (MAP) shows no significant correlation. Both single and multiple linear regression analyses fail to confirm the correlation between leaf physiognomy and precipitation, which may result from the similarity of modern spatial distribution of temperature and precipitation in China. Our results show that, due to variations in climatic conditions among sampling regions, leaf physiognomic characters that correlate to precipitation are not consistent worldwide, and applications of models without considering regional constraints could mislead our understanding of palaeoclimate. Therefore, when choosing a leaf physiognomic model for palaeoclimate reconstructions, it is important to determine if the leaf physiognomy of the palaeoflora lies within the leaf physiognomic spectrum of the model used.