Reduction of helium permeation in microfabricated cells using aluminosilicate glass substrates and Al2_2O3_3 coatings

The stability and accuracy of atomic devices can be degraded by the evolution of their cell inner atmosphere. Hence, the undesired entrance or leakage of background or buffer gas, respectively, that can permeate through the cell walls, should be slowed down. In this work, we investigate helium permeation in microfabricated alkali vapor cells filled with He and whose windows are made of borosilicate glass (BSG) or aluminosilicate glass (ASG). The permeation is then derived from routine measurements of the pressure-shifted hyperfine transition frequency of an atomic clock. We first confirm that ASG reduces He permeation rate by more than two orders of magnitude, in comparison with BSG. In addition, we demonstrate that Al$_2$O$_3$ thin-film coatings, known to avoid alkali consumption in vapor cells, can also significantly reduce He permeation. The permeation through BSG is thereby reduced by a factor 110 whereas the one through ASG is decreased by a factor up to 5.8 compared to uncoated substrates. These results may contribute to the development of miniaturized atomic clocks and sensors with improved long-term stability or sensitivity.Comment: 7 pages, 5 figure

Effect of garlic on cardiovascular disorders: a review

Garlic and its preparations have been widely recognized as agents for prevention and treatment of cardiovascular and other metabolic diseases, atherosclerosis, hyperlipidemia, thrombosis, hypertension and diabetes. Effectiveness of garlic in cardiovascular diseases was more encouraging in experimental studies, which prompted several clinical trials. Though many clinical trials showed a positive effect of garlic on almost all cardiovascular conditions mentioned above, however a number of negative studies have recently cast doubt on the efficary of garlic specially its cholesterol lowering effect of garlic. It is a great challenge for scientists all over the world to make a proper use of garlic and enjoy its maximum beneficial effect as it is the cheapest way to prevent cardiovascular disease. This review has attempted to make a bridge the gap between experimental and clinical study and to discuss the possible mechanisms of such therapeutic actions of garlic

The design, fabrication and characterization of fluidic membranes for micro-engines with the aim of frequency lowering

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Fuzzy logic–based clinical decision support system for the evaluation of renal function in post‐Transplant Patients

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Thermal management of fully LTCC-packaged Cs vapour cell for MEMS atomic clock

International audienceThis paper describes a study of the thermal behaviour of fully packaged Caesium vapour cell developed in the framework of the European collaborative research project called "MEMS atomic clocks for timing, frequency control and communications (MAC-TFC)". This cell, along with various electronic and optical components, is embedded in a Low Temperature Co-fired Ceramics (LTCC) structure, in order to build a compact MEMS-based atomic clock. Functioning of such atomic clock depends on inner and outer environment of the Cs vapour cell, including parameters such as pressure and temperature of buffer gas. This paper is then devoted to study the thermal behaviour of a fully LTCC-packaged Cs vapour cell according to the ambient temperature change when it is locally temperature controlled. Simulations have been carried out by using analytical modelling and finite element based softwares. Different solutions concerning the LTCC structure such as bridges/suspensions, vacuum environment, metallic coating, as well as the optimal positions of the temperature-control elements have been investigated. Finally, preliminary experiments based on a prototype resulting from this study are presented and an additional solution based on the dynamic adjustment of the set temperature as a function of the ambient temperature is proposed

The Moodle e-learning Portal of De La Salle Health Sciences Institute and the associated advantages and disadvantages as encountered by physical therapy students and faculty

This study used descriptive research design. The selected respondents were 263 physical therapy students and five (5) physical therapy faculty members using convenience sampling. Two (2) different, self-formulated survey questionnaires, comprising of the respondents\u27 demographic data and a checklist, were distributed to the students and faculty respondents respectively. Data was analyzed through frequency and percentage. The results for the top advantages were schedule flexibility, being able to balance responsibilities, more efficient time management skills, and easily accessible lecture presentations. Top disadvantages include distraction by non-academic internet activities, slow internet service providers, more efficient teaching and learning in traditional classroom setup, and increased chance of academic dishonesty