Turbulent diffusion in a stably stratified shear layer

Task IIB Research Technical Report Deseret Test Center.TR ECOM-0423-5; Reports control symbol OSD-1366.September 1969.Includes bibliographical references (pages 101-107).Diffusion of a passive substance released from a continuous point source in a stably stratified shear layer is investigated both theoretically and experimentally. Using Monin-Obukhov's velocity profile and assuming a vertical eddy diffusivity which is a power function of the stability parameter z/L, the Eulerian turbulent diffusion equation is solved to obtain expressions for vertical and longitudinal velocities of the center of mass of a cloud in the constant stress region. These expressions give physical substance to those suggested by Gifford (1962} and Cermak (1963} as intuitive extensions of Batchelor's Lagrangian similarity theory. The experimental investigation was made in the Army Micrometeorological Wind Tunnel at the Fluid Dynamics and Diffusion Laboratory of Colorado State University. The wind tunnel has a 6' x 6' x 80' test section. A stably stratified shear layer was produced by heating the air and cooling the wind tunnel floor. Detailed observations of the diffusion field, downwind ground and elevated point sources, have been made using Krypton-85 as a tracer. The concentration characteristics obtained from diffusion experiments show excellent agreement with those observed in the atmosphere. The data compares well with the predictions of similarity theory. It appears that the parameters evaluated in the field by Klug (1968) hold also for the wind tunnel data. The data support the assumption of a Gaussian effect of source height, for elevated releases, on the ground level concentration. An examination of the available solutions to the three dimensional diffusion equation as compared to the data suggests that the detailed diffusion patterns obtained from the wind tunnel experiments may be preferable over such solutions which require arbitrary specification of a lateral diffusivity.For U.S. Army Electronics Command, Atmospheric Sciences Laboratory, Contract No. DAAB07-68-C-0423

Outcome of home mechanical ventilation

OBJECTIVE: To determine the outcome of patients discharged home on portable ventilator. DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: The Aga Khan University Hospital, Karachi from January 2000 to December 2004. PATIENTS AND METHODS: All ventilator-dependent patients discharged home were contacted. Survivors were administered the EQ-5D Quality-of-Life instrument. SPSS version 13 was used to analyze data. RESULTS: Eleven patients were discharged home on invasive ventilation. Mean age was 49 years (range 10-98 years). Cause of ventilatory failure were cervical spine trauma in 36%, primary neurological disease in 27%, critical illness neuropathy and respiratory failure in 18% each. Survival rate was 73%, with three deaths. Mean duration of ventilation was 9.45 months (95% CI 3.24, 15.67). Rate of successful weaning after discharge was 36%, with 4 patients off all forms of ventilatory support and 2 on only nocturnal support. A 2.8 (95% CI 0.5, 16.6) relative risk towards successful weaning was associated with the presence of a family member as the primary care giver. Mean scores on the EQ-5D descriptive tool were; mobility 2 (-/+0.82), self-care 2 (-/+0.82), usual activities 1.86 (-/+0.69), pain/discomfort 1.43(-/+0.79), anxiety/depression 1.29 (-/+0.76). Mean score on the EQ-VAS was 48.2(-/+ 27.3). CONCLUSION: In carefully selected patients, home ventilation is a viable option with the expectation of successful weaning and survival. Patients discharged home on ventilation reported a reasonably good quality of life with proportionately more problems related to independence compared to overall well-being

Measures of disease activity in glaucoma

Glaucoma is the leading cause of irreversible blindness globally which significantly affects the quality of life and has a substantial economic impact. Effective detective methods are necessary to identify glaucoma as early as possible. Regular eye examinations are important for detecting the disease early and preventing deterioration of vision and quality of life. Current methods of measuring disease activity are powerful in describing the functional and structural changes in glaucomatous eyes. However, there is still a need for a novel tool to detect glaucoma earlier and more accurately. Tear fluid biomarker analysis and new imaging technology provide novel surrogate endpoints of glaucoma. Artificial intelligence is a post-diagnostic tool that can analyse ophthalmic test results. A detail review of currently used clinical tests in glaucoma include intraocular pressure test, visual field test and optical coherence tomography are presented. The advanced technologies for glaucoma measurement which can identify specific disease characteristics, as well as the mechanism, performance and future perspectives of these devices are highlighted. Applications of AI in diagnosis and prediction in glaucoma are mentioned. With the development in imaging tools, sensor technologies and artificial intelligence, diagnostic evaluation of glaucoma must assess more variables to facilitate earlier diagnosis and management in the future

Severe anaphylactic shock due to methylene blue dye

AbstractTo identify the sentinel lymph node in melanoma patients, intradermal injection of a radiocolloid tracer and a blue dye are commonly used. Life-threatening side effects of isosulfan blue and Patent Blue V have been well described. However, to the extent of our knowledge, only two life-threatening events with intradermal methylene blue dye have been reported, and none has been reported in the pediatric population. We report a case of a 6-year-old white girl with spitzoid melanoma on her right forearm. She had lymphoscintigraphy under general anesthesia and was taken to the operating room intubated. Intradermal methylene blue (0.2 ml) was injected around the lesion, and after 5 min, wide complex bradycardia was noted and progressed to asystole within less than 1 min. Cardiopulmonary resuscitation was started. Multiple doses of resuscitative drugs were administered, and electrical cardioversion was given twice as well. She recovered completely and transferred to the intensive care unit

Graded elevation of c-Jun in Schwann cells in vivo: gene dosage determines effects on development, remyelination, tumorigenesis, and hypomyelination

Schwann cell c-Jun is implicated in adaptive and maladaptive functions in peripheral nerves. In injured nerves, this transcription factor promotes the repair Schwann cell phenotype and regeneration and promotes Schwann-cell-mediated neurotrophic support in models of peripheral neuropathies. However, c-Jun is associated with tumor formation in some systems, potentially suppresses myelin genes, and has been implicated in demyelinating neuropathies. To clarify these issues and to determine how c-Jun levels determine its function, we have generated c-Jun OE/+ and c-Jun OE/OE mice with graded expression of c-Jun in Schwann cells and examined these lines during development, in adulthood, and after injury using RNA sequencing analysis, quantitative electron microscopic morphometry, Western blotting, and functional tests. Schwann cells are remarkably tolerant of elevated c-Jun because the nerves of c-Jun OE/+ mice, in which c-Jun is elevated ∼6-fold, are normal with the exception of modestly reduced myelin thickness. The stronger elevation of c-Jun in c-Jun OE/OE mice is, however, sufficient to induce significant hypomyelination pathology, implicating c-Jun as a potential player in demyelinating neuropathies. The tumor suppressor P19ARF is strongly activated in the nerves of these mice and, even in aged c-Jun OE/OE mice, there is no evidence of tumors. This is consistent with the fact that tumors do not form in injured nerves, although they contain proliferating Schwann cells with strikingly elevated c-Jun. Furthermore, in crushed nerves of c-Jun OE/+ mice, where c-Jun levels are overexpressed sufficiently to accelerate axonal regeneration, myelination and function are restored after injury.SIGNIFICANCE STATEMENT In injured and diseased nerves, the transcription factor c-Jun in Schwann cells is elevated and variously implicated in controlling beneficial or adverse functions, including trophic Schwann cell support for neurons, promotion of regeneration, tumorigenesis, and suppression of myelination. To analyze the functions of c-Jun, we have used transgenic mice with graded elevation of Schwann cell c-Jun. We show that high c-Jun elevation is a potential pathogenic mechanism because it inhibits myelination. Conversely, we did not find a link between c-Jun elevation and tumorigenesis. Modest c-Jun elevation, which is beneficial for regeneration, is well tolerated during Schwann cell development and in the adult and is compatible with restoration of myelination and nerve function after injury

A Global Collaborative Effort to Enhance Design in a Mechanical Engineering Curriculum in Saudi Arabia

In 2008, King Fahd University of Petroleum and Minerals (KFUPM) in Saudi Arabia and the Massachusetts Institute of Technology (MIT) partnered together to develop project-based curricular material to be tested out in a new undergraduate course offering in KFUPM’s Department of Mechanical Engineering. This paper details some of the unique challenges to collaborating across countries and time zones, and the approaches the KFUPM-MIT team used to address these. These approaches have so far included the establishment of a shared vision for the project and the use of an array of technologies to facilitate distance communication. The paper concludes with a description of lessons learned that might be useful for future programs that plan to engage in international collaboration on design education.Jāmiʻat al-Malik Fahd lil-Batrūl wa-al-Maʻādi

Agricultural livelihoods in coastal Bangladesh under climate and environmental change - A model framework

We describe a novel integrated modelling system aiming to approximate the impact of environmental change on farmers' livelihoods in Bangladesh.</p

Making Space, Making Place: Digital Togetherness and the Redefinition of Migrant Identities Online

Immigrants have played a fundamental role in shaping the life and form of urban public spaces for generations. Their efforts, as many scholars have observed, mostly aimed at creating places of comfort in new and sometimes hostile receiving countries. In recent years, the combined contribution of the built environment and screen-based experiences have shaped migrants’ sense of community and belonging, thus making the concept of online community central to ideas about space and public life. Drawing upon a 3-year online ethnography, the article discusses to what extent new media constitute spaces of digital togetherness, where diasporic experiences and transnational identities are constructed and negotiated. It presents a transnational model of creative media consumption, which helps give insight as to how diasporas and ethnic minorities contribute to the transformation of public space in the Digital Age

Takotsubo cardiomyopathy after a dancing session: a case report

<p>Abstract</p> <p>Introduction</p> <p>Stress-induced (Takotsubo) cardiomyopathy is a rare form of cardiomyopathy which presents in a manner similar to that of acute coronary syndrome. This sometimes leads to unnecessary thrombolysis therapy. The pathogenesis of this disease is still poorly understood. We believe that reporting all cases of Takotsubo cardiomyopathy will contribute to a better understanding of this disease. Here, we report a patient who, in the absence of any recent stressful events in her life, developed the disease after a session of dancing.</p> <p>Case presentation</p> <p>A 69-year-old Caucasian woman presented with features suggestive of acute coronary syndrome shortly after a session of dancing. Echocardiography and a coronary angiogram showed typical features of Takotsubo cardiomyopathy and our patient was treated accordingly. Eight weeks later, her condition resolved completely and the results of echocardiography were totally normal.</p> <p>Conclusions</p> <p>Takotsubo cardiomyopathy, though transient, is a rare and serious condition. Although it is commonly precipitated by stressful life events, these are not necessarily present. Our patient was enjoying one of her hobbies (that is, dancing) when she developed the disease. This case has particular interest in medicine, especially for the specialties of cardiology and emergency medicine. We hope that it will add more information to the literature about this rare condition.</p