Search results

The purpose of this paper is to study the mechanism of efficient sputum excretion from the distal lung by using a tessellationally distal lung model with alveolar pores.

First, a two-dimensional tessellational composite structure of the bronchus, alveoli and alveolar pores (Kohn pore) is constructed with the tessellational splitting and fusion of regular hexagonal elements. Then, the level set method is used to study the effects of alveolar pores and their sizes, expiratory cycles and respiratory intensity.

The existence of alveolar pores is the prerequisite for sputum excretion, and there is an optimal size of alveolar pores for sputum excretion. Strong asymmetric respiration can break the reversibility of the flow at a low Reynolds number and causes significant net displacement of sputum. The expiratory cycle is negatively correlated with the net displacement of sputum. The respiratory intensity is positively correlated with the net displacement of sputum.

This research is helpful for understanding the complex sputum excretion process in diseases, such as pneumonia, and developing corresponding adjuvant therapy.

This study aims to perform flow simulations inside the acinus with fine alveolar pores (Kohn pores) using hexagonal cells and bottom-up geometric modeling, which enabled the elimination of invalid voids using previous top-bottom methods and spherical or circular cells.

Regular hexagonal cells were used to construct alveoli with no gaps via tessellation. Some hexagonal cells were fused to eliminate the inner boundaries to represent the structure of the bronchial tree. For the remaining hexagonal cells, the side lengths of the shared walls were adjusted to construct alveolar pores. Periodic moving boundaries with the same phase were set for all walls to describe synchronous contraction and expansion of the bronchi and alveoli.

More realistic flow characteristics in the distal lung were obtained. The effects of pore size and the mechanism of auxiliary ventilation of alveolar pores were revealed.

To the best of the authors’ knowledge, this is the first numerical simulation study on the function of multiple alveolar pores at the level of pulmonary acini, which will be helpful for simulating the dynamic process of cough and sputum excretion in the future.

The great difficulties which attach to the fixing of legal standards of composition for food products have now to be grappled with by the Departmental Committee appointed by the Board of Agriculture to consider and determine what regulations should be made by the Board, under Section 4 of the Sale of Food and Drugs Act, 1899, with respect to the composition of butter. As we predicted in regard to the labours of the Milk and Cream Standards Committee, so we predict now that the Butter Committee will be unable to do more than to recommend standards and limits, which, while they will make for the protection of the public against the sale of grossly adulterated articles, will certainly not in any way insure the sale of butter of really satisfactory, or even of fair, composition. Standards and limits established by law for the purposes of the administration of criminal Acts of Parliament must of necessity be such as to legalise the sale of products of a most inferior character, to which the term “genuine” may still by law be applied as well as to legalise the sale of adulterated and sophisticated products so prepared as to come within the four corners of the law. It is, of course, an obvious necessity that official standards and limits should be established, and the Board of Agriculture are to be congratulated upon the manner in which they are endeavouring to deal with these extremely knotty problems; but it is important that misconception on the part of the public and the trade with respect to the effect of the regulations to be made should be as far as possible prevented. All that can be hoped for is that the conclusions at which the Committee may find themselves compelled to arrive will not be such as to place too high and too obvious a premium upon the sale of those inferior and scientifically‐adulterated products which are placed in such enormous quantities on the food market.

Memories and musings of the long ago reveal revolutionary changes in the world's food trade and in particular, food sources and marketing in the United Kingdom. Earliest memories of the retail food trade are of many small shops; it used to be said that, given a good site, food would always sell well. There were multiples, but none of their stores differed from the pattern and some of the firms — Upton's, the International, were household names as they are now. Others, eg., the Maypole, and names that are lost to memory, have been absorbed in the many mergers of more recent times. Food production has changed even more dramatically; countries once major sources and massive exporters, have now become equally massive importers and completely new sources of food have developed. It all reflects the political changes, resulting from two World Wars, just as the British market reflects the shifts in world production.

As a key component of the American health care system, the physician office could be the front line in a bioterrorist attack. Nationally and locally, the primary focus on this subject appears to be from a hospital preparedness and public health agency perspective, with little attention devoted to primary physician providers in their own offices, and those specialists to whom patients may be referred. While unrelated to bioterrorism, the recent SARS outbreak also brings to the forefront the need for physicians offices to be able to clinically, operationally, and managerially respond to illnesses that mirror the symptoms of known illnesses, but may be more virulent new organisms or hybrids of existing organisms. If the face of bioterrorism is subtle and slow in its presentation, physicians, in their own offices, could be the first providers of care. Will they be prepared, or will they be among the first fatalities in a bioterrorist attack?