Large-aperture coatings for fusion-class laser systems.

Optical coatings for fusion-class laser systems pose unique challenges, given the large substrate sizes, the high intensities incident on the coatings, and the system-focusing requirements, necessitating a well-controlled optical wavefront. Significant advancements have taken place in the past 30 years to achieve the coating capabilities necessary to build laser systems such as the National Ignition Facility, Laser Mégajoule, OMEGA EP, and OMEGA. This work summarizes the coating efforts and advancements to support such system construction and maintenance.

Stress compensation by deposition of a nonuniform corrective coating.

Surface deformation by coating stress is compensated by prefiguring the substrate with a radially nonuniform layer of dense silica. Stresses in the compensation layer and reflector are modeled using finite element analysis to determine the optimal thickness profile, with the deposited coating reducing the surface deformation by 90%. This process is intended to allow implementation of both the compensation layer and the traditional multilayer coating in a single vacuum cycle.

Glancing-angle-deposited silica films for ultraviolet wave plates.

Birefringent silica films are formed by glancing-angle deposition to fabricate quarter- and half-wave plates at a wavelength of 351 nm. A multilayer design is implemented to achieve low-loss transmittance with a high 351-nm laser-induced damage threshold.

The effects of concentric ring electrode electrical stimulation on rat skin.

Surface electrodes are commonly used electrodes clinically, in applications such as functional electrical stimulation for the restoration of motor functions, pain relief, transcutaneous electrical nerve stimulation, electrocardiographic monitoring, defibrillation, surface cardiac pacing, and advanced drug delivery systems. Common to these applications are occasional reports of pain, tissue damage, rash, or burns on the skin at the point where electrodes are placed. In this study, we quantitatively analyzed the effects of acute noninvasive electrical stimulation from concentric ring electrodes (CRE) to determine the maximum safe current limit. We developed a three-dimensional multi-layer model and calculated the temperature profile under the CRE and the corresponding energy density with electrical-thermal coupled field analysis. Infrared thermography was used to measure skin temperature during electrical stimulation to verify the computer simulations. We also performed histological analysis to study cell morphology and characterize any resulting tissue damage. The simulation results are accurate for low energy density distributions. It can also be concluded that as long as the specified energy density applied is kept below 0.92 (A2/cm4.s(-1)), the maximum temperature will remain within the safe limits. Future work should focus on the effects of the electrode paste.

The role of transrectal ultrasound-guided biopsy-based staging, preoperative serum prostate-specific antigen, and biopsy Gleason score in prediction of final pathologic diagnosis in prostate cancer.

OBJECTIVES: To evaluate the role of ultra sound-guided systematic and lesion-directed biopsies, biopsy gleason score, preoperative serum prostate-specific antigen (PSA) as three objective and reproducible variables to provide a reliable combination in preoperative identification of risk of extraprostatic extension in patients with clinically localized prostate cancer. METHODS: The case records of 813 patients who underwent radical prostatectomy for clinically localized prostate cancer were analyzed. All had multiple systematic biopsies, two to three from each lobe, in addition to lesion-directed biopsies. Additionally, biopsies were done on seminal vesicles (SVs), if abnormal. Based on biopsy results, patients were classified as having stage B1 (T2a-T2b) or B2 (T2c) disease, depending on whether biopsies from one or both lobes were positive and stage C (T3) if there was evidence of SV involvement by biopsy of biopsies from areas of extracapsular extension as seen on transrectal ultrasound (TRUS) were positive. Logistic regression analyses with log likelihood chi-square test was used to define the correlation between individual as well as combination of preoperative variables and pathologic stage. RESULTS: On final pathologic examination, 473 (58%) patients had organ-confined disease, 188 (23%) had extracapsular extension (ECE), with or without positive surgical margins, and 72 (9%) had SV involvement. Eighty (10%) patients had pelvic lymph node metastases. Biopsy-based staging was superior to clinical staging in predicting final pathologic diagnosis. Logistic regression analyses revealed that the combination of biopsy-based stage, preoperative serum PSA, and biopsy Gleason score provided the best prediction of final pathologic stage. Probability plots constructed with these data can provide significant information on risk of extraprostatic extension in individual patients. CONCLUSIONS: This study demonstrates that TRUS-guided systematic biopsy in combination with preoperative serum PSA and biopsy Gleason score may provide a cost-effective approach for management decisions and prognostication in patients with prostate cancer.

The use of flutamide in hormone-refractory metastatic prostate cancer.

In a recent intergroup study under the auspices of the National Cancer Institute, 603 eligible patients with newly diagnosed disseminated adenocarcinoma of the prostate were prospectively randomized in a double-blinded clinical trial to receive either a gonadotropin-releasing hormone analogue (leuprolide) and a nonsteroidal antiandrogen (flutamide) or leuprolide and placebo. Of the 603 eligible patients, 300 were in the leuprolide and placebo arm and 303 were in the leuprolide and flutamide arm. At the time of disease progression, the code was broken: Those patients in the placebo arm were given the opportunity to receive flutamide, and the patients in the flutamide arm were treated at their physician's discretion. There was no survival time distribution difference, based on survival measured from the progression data, between the patients who were received flutamide after progression and those who were treated at their physician's discretion after progression. Furthermore, the addition of flutamide to leuprolide at the time of disease progression resulted in a survival-time distribution that is similar to other treatments of hormone-refractory prostate cancer.

Premalignant lesions and nonsquamous malignancy of the penis and carcinoma of the scrotum.

Premalignant lesions of the penis include cutaneous horn, balanitis xerotica obliterans, and leukoplakia. The true incidence of progression of each of these to squamous-cell carcinoma is unknown. Bowenoid papulosis, erythroplasia of Queyrat, and Bowen's disease are histologically identical to in situ carcinoma. Although the first is consistently benign, the latter two regularly evolve into invasive cancer. Malignant scrotal lesions include squamous-cell carcinoma, liposarcoma, leiomyosarcoma, basal-cell carcinoma, extramammary Paget's disease, erythroplasia of Queyrat, malignant melanoma, and metastases. Hemangioma can be confused with carcinoma.

National Cancer Institute study of luteinizing hormone-releasing hormone plus flutamide versus luteinizing hormone-releasing hormone plus placebo.

A randomized, double-blind trial in patients with disseminated, previously untreated prostate cancer (stage D2) was designed to test the hypothesis that maximal androgen blockade improves the effectiveness of the treatment of prostatic cancer. Six hundred three men received leuprolide in combination with either placebo or flutamide, and were followed for a minimum of 5 years. The 303 patients randomly assigned to receive leuprolide and flutamide had a longer progression-free survival and an increase in the median length of survival compared with the 300 patients receiving leuprolide plus placebo. Differences between the treatments were particularly evident for men with minimal disease and good performance status.

Staging relationships and outcome in early stage testicular cancer: a report from the Testicular Cancer Intergroup Study.

The Testicular Cancer Center Intergroup Study entered surgically staged patients with nonseminomatous tumor and metastases limited to the regional lymph nodes into a previously reported cooperative trial of immediate versus delayed therapy for positive retroperitoneal node disease. Patients with negative nodes (stage I) were placed in an observation registry with specified treatment strategy upon relapse. Of 264 stage I cancer patients 27 (10.2%) had recurrence: 5 of these 27 patients died after recurrence of the testicular malignancies, while 4 other nontumor-related deaths have occurred. Pre-lymphadenectomy staging characteristics observed to predict significantly node positivity are the results of radiological examinations, presence of tumor invasion, vascular invasion and tumor histology. In a multiple logistic regression analysis with these variables, misclassification still occurs in more than a fourth of the patients. Future refinements in diagnosis may allow for better prediction of these patients at risk to have positive lymph nodes and ultimately recurrence. Presently, if assessment of nodal involvement is the objective, noninvasive procedures are not an adequate substitute for surgical staging with modified lymphadenectomy.

Childhood events and circumstances influencing high school completion.

This paper is an empirical exploration of the effects of a variety of family and economic circumstances experienced during childhood on one indicator of success in young adulthood--high school completion. The estimates suggest that parental education and mother's work are positive and significant determinants of high school completion, whereas growing up in a family with more children (who compete for resources), being persistently poor and on welfare, and moving one's residence as a child have significant negative impacts on high school completion. The effects of some family stress and economic events differ depending on the age of the child when they occur. The results support the economic model of investment in children, as well as the welfare culture and socialization models.

Leuprolide with and without flutamide in advanced prostate cancer.

In a randomized, double-blind trial for metastatic prostate cancer (Stage D2), 603 men received leuprolide, a gonadotropin-releasing hormone analog that inhibits the release of gonadotropins, coupled with either placebo or flutamide, a nonsteroidal antiandrogen that inhibits the binding of androgens to the cell nucleus. The 303 men receiving androgen blockade with leuprolide and flutamide demonstrated a longer progression-free survival (16.9 vs. 13.9 months, P = 0.039) and an increased median length of survival (35.0 vs. 27.9 months, P = 0.035). In the subgroup of men with minimal disease and good performance status, the advantages of maximal androgen blockade were more pronounced. It is concluded that combined androgen blockade with leuprolide and flutamide was more effective than leuprolide alone for patients with metastatic cancer of the prostate. The therapeutic benefits, although greatest in patients with minimum disease, need to be evaluated in a prospective, randomized fashion in trials specifically designed for men with minimal disease and good performance status. Exploratory analyses using the black race as an explanatory variable were also performed. Black race is associated with shorter survival times and is also associated with other prognostic factors, including recent weight loss, anemia, elevated phosphatase levels, and pain. These findings suggest the need for future studies of the relationship of black race and response to prostate cancer therapy.

A controlled trial of leuprolide with and without flutamide in prostatic carcinoma.

To test the hypothesis that maximal androgen blockade improves the effectiveness of the treatment of prostatic cancer, we conducted a randomized, double-blind trial in patients with disseminated, previously untreated prostate cancer (stage D2). All 603 men received leuprolide, an analogue of gonadotropin-releasing hormone that inhibits the release of gonadotropins, in combination with either placebo or flutamide, a nonsteroidal antiandrogen that inhibits the binding of androgens to the cell nucleus. As compared with the 300 patients receiving leuprolide and placebo, the 303 patients randomly assigned to receive leuprolide and flutamide had a longer progression-free survival (16.5 vs. 13.9 months; P = 0.039) and an increase in the median length of survival (35.6 vs. 28.3 months; P = 0.035). The differences between the treatments were particularly evident for men with minimal disease and good performance status; however, further studies should be conducted in this subgroup. Symptomatic improvement was greatest during the first 12 weeks of the combined androgen blockade, when leuprolide alone often produces a painful flare in the disease. We conclude that in patients with advanced prostate cancer, treatment with leuprolide and flutamide is superior to treatment with leuprolide alone.

Computer simulation of cerebral microhemodynamics.

Microvascular network hemodynamics was simulated by computer in an anatomically reconstructed cerebral microvascular network. A video microscope system was used for three-dimensional mapping of the vessel network in the rat brain cortex. The complete topology, length and mean diameter of the microvessels were determined. The distribution of blood flow and red cell flux in the network was calculated based on vessel resistance estimated from geometrical data and a rheological model of blood. This model described apparent relative blood viscosity as a function of vessel diameter and local discharge hematocrit. The calculations predicted highly heterogeneous cell flux distribution at any feed hematocrit between 10 and 40 percent. The frequency distribution of microvessel hematocrit was bimodal and included values exceeding the feed hematocrit value. A probabilistic simulation of cell transit resulted in transit time distributions which agree with experimental findings. The most probable transit time and capillary path length and 4s and 300 microns, respectively.

Total ankle arthroplasty. A procedural review.

Total ankle arthroplasty is a demanding surgical procedure, but the advantages of maintaining motion in the tibiotalar joint in the patient with systemic arthritis are known. Although the technology of ankle implant arthroplasty is still evolving, current results in properly selected patients approach the results of other leg implants.

The clinical significance of unconventional orchiectomy approaches in testicular cancer: a report from the Testicular Cancer Intergroup Study.

Despite the clear indications for an inguinal approach, reports indicate that up to 53 per cent of all testicular tumors are diagnosed or initially treated in a manner inconsistent with the classical radical orchiectomy. Of 462 evaluable patients from the Testicular Cancer Intergroup Study 47 (10.2 per cent) had undergone a nonclassical orchiectomy as the initial surgical management. This group was analyzed separately to determine the prognostic significance of needle aspiration, open biopsy, a scrotal approach and tumor contamination. Within this group of patients, those who received no adjuvant chemotherapy exhibited no increase in local or distant recurrence. While the recurrence rate similarly was not adversely affected by even gross tumor contamination, this subset underwent significantly more aggressive local surgical salvage (p less than 0.01), with scrotectomy procedures found to be of probable therapeutic value. While not to be condoned, we conclude that deviations from the classical orchiectomy, when followed by appropriate surgical management and close observation, can be of little clinical impact.

Immediate adjuvant chemotherapy versus observation with treatment at relapse in pathological stage II testicular cancer.

Between 1979 and 1984, 195 evaluable patients were entered in an international multicenter study comparing two regimens for patients with completely resected pathological Stage II testicular cancer (that is, with positive retroperitoneal lymph nodes). All patients had undergone orchiectomy and dissection of the retroperitoneal lymph nodes. They were randomly assigned to be treated with two cycles of immediate adjuvant cisplatin-based chemotherapy or to be observed monthly with treatment at relapse. The median follow-up period was four years. Of the 97 patients assigned to adjuvant chemotherapy, 6 (6 percent) had a recurrence; however, only 1 had received adjuvant chemotherapy before the recurrence. Three died (one of testicular cancer), and 94 of the 97 survived. Of the 98 patients who were observed, 48 (49 percent) had a relapse. However, almost all patients with relapses were effectively treated, and 93 of the 98 are alive and disease-free; 3 have died of testicular cancer. No identifiable factors were strongly associated with the risk of relapse. We conclude that two courses of cisplatin-based adjuvant chemotherapy will almost always prevent relapse in pathological Stage II testicular cancer treated with orchiectomy and retroperitoneal-lymph-node dissection. However, when surgery, follow-up, and chemotherapy are optimal, observation with chemotherapy only for relapse will lead to equivalent cure rates.

The Canton Asylum for Insane Indians: an example of institutional neglect.

Based on archival data, the author chronicles the history of the Canton (S.D.) Asylum for Insane Indians, which was established by Congress in 1903 and was closed in 1934 because of inadequate conditions. In 1926 a nationwide survey found that patients at Canton received minimal care. The rates of patient death and discharge at Canton reported in a 1931 survey compared unfavorably to those at other mental institutions in the U.S. The 1929 and 1933 inspection reports of psychiatrist Samuel Silk, which documented the hospital's outmoded custodial care and questioned the necessity of institutionalization for 35 to 40 of Canton's 90 patients, played a key role in the decision to close the asylum. The author attributes the decline of the Canton Asylum to gradual neglect by its superintendent and various government agencies.