Electrical impedance-based particle detection or Coulter counting, offers a lab-on-chip compatible method for flow cytometry. Developments in this area will produce devices with greater portability, lower cost, and lower power requirements than fluorescence-based flow cytometry. Because conventional Coulter apertures are prone to clogging, hydrodynamic focusing improves the device by creating fluid-walled channels with variable width to increase sensitivity without the associated risk of blocking the channel. We describe a device that focuses the sample in three dimensions, creating a narrow sample stream on the floor of the channel for close interaction with sensing electrodes. The key to this design is a stepped outlet channel fabricated in a single layer with soft lithography. In contrast to previous impedance-based designs, the new design requires minimal alignment with the substrate. Three-dimensional focusing maximizes the sensitivity of the device to cell-size particles within much larger channels. Impedance-based particle sensing experiments within this device show an increase in percentage conductivity change by a factor of 2.5 over devices that only focus the sample in the horizontal direction.

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Many factors can influence the prognosis of cancer of the cervix. They range from clinical staging, various histologic cell types, to extensions into the endometrium. Very little is known about the influence of the patients‐ age and constitutional status of the host (patient) on the prognosis of cervical cancer. Over the past several years, we have been observing that when cancer of the cervix occurs in the relatively young patient, they tend to be more aggressive and inspite of the usual accepted treatment, the majority of them do not survive their disease. From 1969 to 1974, 561 patients with proven invasive squamous cell carcinoma of the cervix were treated by irradiation only in the Department of Radiation Therapy, University of Maryland Hospital. Of these, 94 patients were studied and their ages ranged from 23 to 39 years. They were staged following FIGO guidelines and subject to the usual irradiation treatment for cervical cancer. All patients are eligible for a minimum five‐year follow‐up and the absolute five‐year disease‐free survival is as follows: Stage I, 70.2%, (33/47); Stage II, 54%, (14/26); Stage III, 17%, (3/18) and Stage IV, 0%, (0/3). One of the most interesting features observed in Stage I and II disease is distant disease; 26% for Stage I and 42% for Stage II. Further analysis of our result for Stage I and II shows that tumor grading may be responsible for poor outcome. Three Grade systems were used for the study and the result clearly shows that Grade III or poorly differentiated squamous cell carcinoma had the poorest five‐year survival; for example, survival for Stage I disease is 43% and 44% for Stage II. Analysis of the failures following the treatment suggests that about 50% of patients with Grade III disease have already had distant disease by the time the diagnosis was made. Recommendations for futher appropriate treatment is suggested.

Response of intrathoracic symptoms to thoracic irradiation was evaluated in 330 patients. Superior vena caval syndrome and hemoptysis showed the best response, with rates of 86% and 83%, respectively, compared to 73% for pain in the shoulder and arm and 60% for dyspnea and chest pain. Atelectasis showed re-expansion in only 23% of cases, but this figure increased to 57% for patients with oat-cell carcinoma. Vocal cord paralysis improved in only 6% of cases. Radiation therapy has a definite positive role in providing symptomatic relief for patients with carcinoma of the lung.

During the period from 1969--1974, 561 patients with proven invasive squamous cell carcinoma of the cervix were treated by irradiation only in the Department of Radiation Therapy, University of Maryland Hospital. Of these, 82 patients were identified as having D & C positive for squamous cell cancer present in the curettings with or without endometrial tissue. Clinical staging was done using FIGO guidelines and the treatment of endometrial extension was the same as with regular cervical cancer. Of 82 cases who are eligible for a minimum five-year follow-up, the absolute five-year survival is as follows: Stage I, 68%, (17/25); Stage II, 62% (18/29); Stage III, 40% (10/25); Stage IV, 0% (0/3). The most interesting features are the local and distant failures in Stage I and II disease. Local failure in Stage I and II in this study is in line with other series. Distant metastasis, however, occurs at the rate of 20% in Stage I between 1--2 years after treatment (as compared to the control of 5%). In Stage II, the distant disease increases to 24% with a substantial number of local failure with distant metastasis. Based on our findings and others, it seems appropriate to suggest D &nd C be done routinely in order to identify the extension of cancer into the endometrium and treat them properly. Also it appears appropriate to re-examine our policy of the treatment to minimize both local and distant failures with suggestions outlined in Schema I and II along with possibility of a future chemotherapeutic management to minimize the distant disease.