The ecology of echo

Echo is a generic ecosystem model in which evolving agents are situated in a resource-limited environment. The Echo model is described, and the behavior of Echo is evaluated on two well-studied measures of ecological diversity: relative species abundance and the species-area scaling relation. In simulation experiments, these measures are used to compare the behavior of Echo with that of a neutral model, in which selection on agent genotypes is random. These simulations show that the evolutionary component of Echo makes a significant contribution to its behavior and that Echo shows good qualitative agreement with naturally occurring species abundance distributions and species-area scaling relations.     

Overexpression of Glut1 and Glut3 in stage I nonsmall cell lung carcinoma is associated with poor survival

We report the electrophysiologic findings of myoclonus in a patient with Huntington's disease (HD). This patient was studied postoperatively after a bilateral fetal cell transplant in his striatum. Incomplete transient improvement was seen in the myoclonus, followed by gradual deterioration. The myoclonus itself had a cortical correlate and was associated with an enlarged somatosensory evoked potential (SEP), consistent with the presence of cortical reflex myoclonus. An enlarged SEP has not been previously reported in myoclonus associated with HD. The postulated mechanisms for myoclonus, when it occurs in HD, have differed in the literature. The reason for the transient improvement of the myoclonus following transplantation is unclear, but this case raises the possibility that basal ganglia circuits may modulate cortical myoclonic activity.     

Meckel''s diverticulum presenting as gastric outlet obstruction: case report

We report a case of gastric outlet obstruction simulating gastric antral neoplasm resulting from a perforated Meckel's diverticulum. Presentation of this nature has not been previously reported.     

Extracorporeal photochemotherapy (photopheresis) induces apoptosis in lymphocytes: a possible mechanism of action of PUVA therapy

The mechanism of action of psoralen plus UVA (PUVA) and photopheresis is not entirely understood. These therapies are assumed to be immunomodulating partly by gradually decreasing leukocyte viability. We investigated whether this delayed form of cell death was due to apoptosis. Untreated and treated (PUVA exposed) leukocytes obtained from six patients with systemic sclerosis and (untreated) leukocytes from healthy control individuals were studied. Qualitative gel electrophoresis and quantitative in situ nick translation analysis of DNA fragmentation was performed. Apoptosis of the treated cells did occur (gel electrophoresis) after 24 h. At t = 0 h, immediately after exposure to PUVA, there was no evidence of DNA fragmentation in the treated cells. The percentage of treated cells undergoing apoptosis was 20-55% at t = 24 h (in situ nick translation). The untreated leukocytes of the patients and the healthy individuals showed no distinctive rise in apoptotic cells. Apoptosis of the leukocytes after PUVA or photopheresis treatment might be a mechanism of action and might explain the therapeutic response.     

立达C60型梳棉机使用经验

介绍了一印度尼西亚纺纱厂使用瑞士立达机械工程公司生产的C60型梳棉机在环锭细纱操作方面运转性能和质量的经验。     

Probabilistic Weibull behavior and mechanical properties of MEMS brittle materials

The objective of this work is to present a brief overview of a probabilistic design methodology for brittle structures, review the literature for evidence of probabilistic behavior in the mechanical properties of MEMS (especially strength), and to investigate whether evidence exists that a probabilistic Weibull effect exists at the structural microscale. Since many MEMS devices are fabricated from brittle materials, that raises the question whether these miniature structures behave similar to bulk ceramics. For bulk ceramics, the term Weibull effect is used to indicate that significant scatter in fracture strength exists, hence requiring probabilistic rather than deterministic treatment. In addition, the material's strength behavior can be described in terms of the Weakest Link Theory (WLT) leading to strength dependence on the component's size (average strength decreases as size increases), and geometry/loading configuration (stress distribution). Test methods used to assess the mechanical properties of MEMS, especially strength, are reviewed. Four materials commonly used to fabricate MEMS devices are reviewed in this report. These materials are polysilicon, single crystal silicon (SCS), silicon nitride, and silicon carbide.     

Metastatic carcinoma of the prostate mimicking primary carcinoid tumor of the lung and mediastinum

AIMS: To investigate the current use of thrombolytic therapy in the management of patients with acute myocardial infarction and to determine the potential for an increased use of thrombolysis or percutaneous transluminal coronary angioplasty (PTCA). METHODS AND RESULTS: All hospitalised cases of acute myocardial infarction were identified in three health districts in the UK (population of 960,000) in patients under the age of 76 years during a 2-year period; 2439 patients had acute myocardial infarction, of whom 1264 (52%) received thrombolytic therapy. Failure to administer thrombolytic therapy was a result of the absence of diagnostic electrocardiograms in 712 (29.2%) patients, late presentation in 127 (5.2%), therapeutic error in 112 (4.6%), presence of a bleeding risk in 139 (5.7%) and other miscellaneous reasons in 80 (3.3%) patients. Thirty-eight of the 139 patients in whom bleeding risk was reported as a contra-indication could, in retrospect, have received thrombolytic therapy and a further 76 would have been suitable for primary PTCA. CONCLUSIONS: The potential for increasing the use of thrombolytic therapy seems to be limited and is unlikely to make a major impact on the in-hospital mortality from acute myocardial infarction. However, primary PTCA should be considered in those who are ineligible for thrombolysis because of bleeding risk as a contra-indication.     

THE MEASUREMENT OF BEER AND WORT COLOUR — A NEW APPROACH

A new method of beer and wort colour measurement is described. This uses the principle of tristimulus colour measurement. The results show excellent correlation with those obtained using the comparator disc method. Tristimulus colour measurement is now in routine use in nineteen locations within Whitbread and has become the standard colour measurement methodology.     

Dr. James A. Koutsky 1940-1994

James A. Koutsky, Professor in the Chemical Engineering Department at the Univer- sity of Wisconsin, died on November 25,1994. He was born on December 1,1940, in Parma, Ohio, the son of Joseph and Marion Koutsky. Dr. Koutsky received B. S., M. S. degrees (both in Chemical Engineering) and a Ph.D. in Polymer Science, all from Case Western Reserve University.