Search

A prototype reusable large-volume (2mL) autoinjector (LVAI) was designed to compare injection performance of a novel 27 gauge ultra-thin wall (UTW) pre-filled syringe (PFS) cannula (8mm external cannula length, 14.4mm total needle length) against an existing 27 gauge special thin wall (STW) PFS cannula (12.7mm external cannula length, 19mm total needle length) across a range of injectate viscosities (2.3-30 cP) in a series of in vivo feasibility studies in swine. The UTW cannula had an approximately 30% greater cross-sectional lumen area than the STW cannula. The target exposed needle length was adjusted to ensure appropriate needle penetration depth and achieve injectate deposition in the subcutaneous (SC) tissue. Delivery time and volume, injection site leakage, injectate depot location, and local tissue effects were examined. The STW and UTW cannulae both provided effective SC delivery of contrast placebo solutions, and were able to accommodate injectate viscosity up to 30 cP without quantifiable leakage from the tissue and with minor tissue effects which resolved within 1-2 hours. Delivery times at each viscosity were significantly different between PFS types with the UTW PFS producing faster delivery times. In a histological substudy of the UTW cannula using injectate viscosities up to 50 cP, injection site reactions were rare and, when present, were of minimal severity. This series of studies demonstrates the feasibility of LVAI SC injection and informs autoinjector and PFS design considerations. Use of a UTW cannula may enable more rapid LVAI injections with minimal tissue effects, especially for higher viscosity formulations. [ABSTRACT FROM AUTHOR]

Little is known about the availability of residual fertilizer-N and cotton (Gossypium spp.) residue-N to subsequent crops. This study determined the effects of two soil types and N fertilization rates on the recovery of residual [sup.15]N-fertilizer and [sup.15]N from labeled cotton residue in the soil and plants of subsequent cotton crops. Microplots in the San Joaquin Valley, California, on a Panoche clay loam [fine-loamy, mixed (calcareous), thermic Typic Terriorthents] and a Wasco sandy loam (coarse-loamy, mixed, nonacid, thermic Typic Torriorthents) were used to trace the fate of [sup.15]N from labeled abovcground cotton residue separately from the [sup.15]N in roots and soil. Total [sup.15]N -fertilizer recovery in the second year after application averaged 5.8% for Acala (G. hirsutum L.) and 2.9% for Pima (G. barbadense L.) cotton. In the third year after application, total [sup.15]N-fertilizer recovered by Acala averaged 2.0% on the clay loam soil and 3.3% on the sandy loam. Most of this recovered [sup.15]N-fertilizer was cycled through soil pools and roots and only small amounts originated from labeled aboveground residue. Virtually all of the [sup.15]N applied in the form of labeled aboveground residue and recovered in the soil was found in the top 0.3 m. The [sup.15]N-fertilizer which cycled through belowground pools was found mainly in the top 0.6 m of the soil. Recovery of residual [sup.15]N-fertilizer appears to contribute little to total cotton N uptake in the second and third crop after application.

A better understanding of plant nitrogen (N) dynamics in modern varieties of Acala (Gossypium hirsutum L.) and Pima (G. barbadense L.) cotton grown with prevailing management practices may help in the design of N management strategies that optimize N utilization and lint yields. The response of Acala cotton to different N fertility levels was evaluated on a Panoche clay loam (fine-loamy, mixed (calcareous), thermic Typic Torriorthents) and on a Wasco sandy loam (coarse-loamy, mixed, nonacid, thermic Typic Torriorthents). Nitrogen treatments of 56, 112, 168, and 224 kg N [ha.sup.-1] and check plots were established in 1998, 1999, and 2000. Plant shoots were collected and fractionated into different components at several growth stages for determination of N concentration. Both Acala and Pima tissue N concentrations were strongly affected by developmental stage and N treatment. Acala tissue N concentrations differed significantly between soil types. Maximum N uptake rates of both Pima and Acala occurred between early square and early bloom. Physiological N use efficiency averaged 11.4 kg lint [kg.sup.-1] plant N for Acala grown on the Panoche clay loam and 9.4 kg [kg.sup.-1] on the Wasco sandy loam, and 13.2 kg [kg.sup.-1] for Pima grown on Panoche day loam. Leaf N concentration as an in-season indicator of N status and estimates of seasonal soil N mineralization potential may be useful in optimizing cotton N management., NITROGEN MANAGEMENT is an important factor in optimizing cotton lint yield and quality. Cotton is produced on a wide range of soil types, in contrasting climatic conditions, and with varied [...]

A semiactive method of Fourier-transform infrared (FTIR) remote sensing has been developed and field tested. The method replaces the sender telescope of an active technique with an extended, heated broadband source. The output of the extended source (a commercial griddle) is not collimated and thus facilitates alig~ment by having the detector optics simply point at the griddle. The present source fills the detector's field of view at 100 m and maintains a temperature ~80 K warmer than ambient. In field tests with live CO releases, the method was ~30 times less sensitive than active methods, but ~30 times more sensitive than passive methods, with far greater sensitivity in the midwave infrared. OCIS codes: 070.0070, 120.0120, 280.0280, 300.0300.