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51.
A series of experiments was conducted under controlled soil moisture and temperature conditions in a growth chamber to examine the effect of a range of nutrient seed coatings on the emergence to wheat (Triticum aestivum L. cv. Kite) and oats (Avena sativa L. cv. Blackbutt) sown in a coarse sandy loam soil. Final emergence of oats was not reduced by a coating containing 10 kg P ha–1 (as monocalcium phosphate [MCP]) whereas the same coating reduced wheat emergence by 15%. The emergence of both wheat and oats was severely reduced by urea coatings (supplying 10 kg N ha–1) to 33 and 13% respectively; this injury was lessened markedly by the inclusion of phenyl phosphorodiamidate (PPD) in the urea coatings at 1% (w/w) (emergence increased to 66 and 56% respectively).Low soil moisture (67% of field capacity [FC]) resulted in almost no emergence of wheat coated with urea (± bentonites of different pH). In soil at FC, the addition of bentonite of pH 5 (B5) to urea coatings permitted greater emergence (54%) than when bentonite of pH 9 (B9) was added (32%) which, in turn, permitted greater emergence than urea coating alone (10%). When PPD and bentonite (B5 or B9) were combined either singly or together with urea in seed coatings, PPD was more effective than either of the bentonites in reducing injury and masked the slight positive effect of B5.Coatings containing various combinations of N and P sources (at 3.6 and at 8 kg ha–1 respectively) all reduced the emergence of wheat compared to raw seed (91% emergence). When applied alone, MCP was least damaging (74%); the combination of MCP with ammonium sulfate (AS) caused somewhat more injury (68%) whilst combination with calcium nitrate (CN) caused most injury (29%). In contrast, CN alone caused relatively little damage (73%) whilst AS alone was more damaging (50%). There was no significant regression found between percentage emergence and either the calculated partial salt index or the pH of the nutrient coatings. Further work is needed to examine the mechanisms of injury due to nutrient seed coatings so that safe but effective formulations can be developed.  相似文献   
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53.
A prospective study concerning colorectal polyps in symptomatic patients was held at Lima, Perú, an area considered of low incidence for colorectal neoplasia. In 137 patients, 272 polyps were resected by colonoscopic polypectomy or surgery. 55.9% were adenomas, 40.4% non neoplastic polyps and 3.7% polypoid carcinomas. The distribution of polyps, and the incidence of dysplasia and malignant changes in the adenomas, were similar of that reported in areas with high incidence of colorectal cancer. A high proportion of patients with adenomas (21.4% had a synchronous advanced carcinoma, specially if there were multiple adenomas. The figure was lower in patients with only non neoplastic polyps (7.5%). There were no cases of "de novo" carcinoma. This evidence suggest that adenomas play an essential role in colorectal cancer histogenesis, even in areas of low incidence of this neoplasia.  相似文献   
54.
MD Dake  DC Miller  RS Mitchell  CP Semba  KA Moore  T Sakai 《Canadian Metallurgical Quarterly》1998,116(5):689-703; discussion 703-4
OBJECTIVE: Our goal was to determine whether endovascular stent-grafting is feasible and effective for patients with aneurysms of the descending thoracic aorta. METHODS: Starting in July 1992, we conducted a prospective, uncontrolled clinical trial in 103 patients (mean age 69 years [range 34-89 years]) who underwent endovascular treatment of aneurysms of the descending thoracic aorta using a custom-fabricated, self-expanding stent-graft device. Follow-up was 100% complete and averaged 22 months. Sixty-two patients (60%) were judged not to be reasonable candidates for a conventional "open" surgical procedure. RESULTS: Complete thrombosis of the aneurysm was ultimately achieved in 86 (83%) patients. The early mortality rate was 9% +/- 3% (+/- 70% CL). Multivariable analysis revealed that myocardial infarction or stroke was linked with a higher likelihood of early death (P = .001). Early serious complications included paraplegia in 3% +/- 2% and stroke in 7% +/- 3%. Actuarial survival estimates at 1 year and 2 years were 81% +/- 4% and 73% +/- 5% (+/- 1 SE), respectively; being judged not to be a surgical candidate portended a higher probability of death (P = .003). According to the intent-to-treat principle, "treatment failure" (including all late sudden unexplained deaths) occurred in 38 patients; 53% +/- 10% of patients were free from treatment failure at 3.7 years. Stent-graft related complications occurred commonly and were linked with several anatomic, technical, and patient-related risk factors. CONCLUSIONS: This 5-year clinical trial involving use of a "first generation" device indicates that endovascular stent-grafting of descending thoracic aortic aneurysms is feasible with acceptable medium-term results. More refined, commercially developed devices available today offer less traumatic and more precise stent-graft deployment; these major technical advantages, coupled with important lessons we have learned over time and better patient selection, should be associated with more salutary clinical results in the future.  相似文献   
55.
Increasing numbers of children are living in families consisting of grandparents and grandchildren. This paper presents findings of a study in which 123 caregiving grandmothers were interviewed. Fifty-eight percent of these grandmothers were "career caregivers," whose homes were always filled with a child or grandchild. Most of them were in good to excellent physical health and their mental health was at least as good as that of a national sample. Regression analyses found that having a life-threatening physical condition, being younger and white explained psychological anxiety; and having a life-threatening physical condition and not being employed explained psychophysiological mental health symptoms. These findings suggest that some grandmothers are at risk for mental health symptoms and raise questions about the implications of caregiving of grandchildren for women.  相似文献   
56.
Methanol-induced conformational transitions of hen egg white lysozyme were investigated with a combined use of far- and near-UV CD and NMR spectroscopies, ANS binding and small-angle X-ray scattering. Addition of methanol induced no global change in the native conformation itself, but induced a transition from the native state to the denatured state which was highly cooperative, as shown by the coincidence of transition curves monitored by the far- and near-UV CD spectroscopy, by isodichroic points in the far- and near-UV CD spectra and by the concomitant disappearance of individual 1H NMR signals of the native state. The ANS binding experiments could detect no intermediate conformer similar to the molten globule state in the process of the methanol denaturation. However, at high concentration of methanol, e.g., 60% (v/v) methanol/water, a highly helical state (H) was realized. The H state had a helical content much higher than the native state, monitored by far-UV CD spectroscopy, and had no specific tertiary structure, monitored both by near-UV CD and NMR spectroscopy. The radius of gyration in the H state, 24.9 angstroms, was significantly larger than that in the native state (15.7 angstroms). The Kratky plot for the H state did not show a clear peak and was quite similar to that for the urea-denatured state, indicating a complete lack of globularity. Thus we conclude that the H state has a considerably expanded, flexible broken rod-like conformation which is clearly distinguishable from the "molten globule" state. The stability of both N and H states depends on pH and methanol concentration. Thus a phase diagram involving N and H was constructed.  相似文献   
57.
Accusations of rape or sexual harassment are currently very high-profile in the military. This article discusses rape allegations in the military legal system from a psychiatric perspective. The original definition of "rape trauma syndrome" and subsequent psychiatric thinking about the diagnosis are briefly outlined. Common reactions seen in military victims in this era are described. A prototypical military case is presented. An adequate evaluation of an alleged victim is outlined. Credentials and preparation of an expert witness are also briefly discussed, with cautions about the use of expert testimony in cases of alleged sexual assault and rape trauma syndrome.  相似文献   
58.
Sixteen experienced cochlear implant patients with a wide range of speech-perception abilities received the SPEAK processing strategy in the Nucleus Spectra-22 cochlear implant. Speech perception was assessed in quiet and in noise with SPEAK and with the patients' previous strategies (for most, Multipeak) at the study onset, as well as after using SPEAK for 6 months. Comparisons were made within and across the two test sessions to elucidate possible learning effects. Patients were also asked to rate the strategies on seven speech recognition and sound quality scales. After 6 months' experience with SPEAK, patients showed significantly improved mean performance on a range of speech recognition measures in quiet and noise. When mean subjective ratings were compared over time there were no significant differences noted between strategies. However, many individuals rated the SPEAK strategy better for two or more of the seven subjective measures. Ratings for "appreciation of music" and "quality of my own voice" in particular were generally higher for SPEAK. Improvements were realized by patients with a wide range of speech perception abilities, including those with little or no open-set speech recognition.  相似文献   
59.
A 36-year-old man with a history of hypertrophic obstructive cardiomyopathy presented to the emergency room with "stabbing" chest pain. He had undergone dual-chamber pacemaker implantation in 1993 using an atrial lead (Accufix; Telectronics; Englewood, Colo) and a myomectomy in 1996 during which the distal portion of the atrial lead was removed. Digital fluoroscopy revealed that the retention wire had migrated out of the remaining atrial lead and perforated the right atrium. The retention wire was successfully removed percutaneously. The need for complete removal of the retention wire in the Accufix lead at the time of open-heart surgery is emphasized.  相似文献   
60.
The complex hierarchical structure of lamellar bone makes understanding structure–mechanical function relations, very difficult. We approach the problem by first using the relatively simple structure of parallel-fibred bone to construct a mathematical model for calculating Young's moduli in three-dimensions. Parallel-fibred bone is composed essentially of arrays of mineralized collagen fibrils, which are also the basic structural motif of the individual lamellae of lamellar bone. Parallel-fibred bone structure has orthotropic symmetry. As the sizes and shapes of crystals in bone are not well known, the model is also used to compare the cases of platelet-, ribbon- and sheet-reinforced composites. The far more complicated rotated plywood structure of lamellar bone results in the loss of the orthotropic symmetry of individual lamellae. The mathematical model used circumvents this problem by sub-dividing the lamellar unit into a thin lamella, thick lamella, transition zone between them, and the recently observed back-flip lamella. Each of these is regarded as having orthotropic symmetry. After the calculation of their Young's moduli they are rotated in space in accordance with the rotated plywood model, and then the segments are combined to present the overall modulus values in three-dimensions. The calculated trends compare well with the trends in microhardness values measured for circumferential lamellar bone. Microhardness values are, as yet, the only measurements available for direct comparison. Although the model is not directly applicable to osteonal bone, which is composed of many hollow cylinders of lamellar bone, the range of calculated modulus values and the trends observed for off-axis calculations, compare well with measured values. © 1998 Chapman & Hall  相似文献   
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