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Heyer EJ, Delphin E, Adams DC, Rose EA, Smith CR, Todd CJ, Ginsburg M, Haggerty R, McMahon DJ. Cerebral dysfunction after cardiac operations in elderly patients. Ann Thorac Surg 1995; 60:1716-22. [PMID: 8787469 DOI: 10.1016/0003-4975(95)00719-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Cerebral injury remains a significant complication of cardiac operations. We determined the incidence of cerebral dysfunction in a population of elderly patients undergoing open chamber cardiac operations (group 1) as compared with a younger population (group 2) and an age-matched group of elderly patients undergoing major noncardiac operations (group 3). METHODS Sixty-eight patients (55 for open chamber cardiac operations and 13 for noncardiac operations) were prospectively studied. Patients were evaluated preoperatively and postoperatively before hospital discharge using a complete neurologic examination and a battery of standard neuropsychometric tests, and at surgical follow-up with neuropsychometric tests only. RESULTS Postoperative changes detected by neurologic examination consisted of the appearance of new primitive reflexes in all groups. No statistically significant differences in incidence were found. The neuropsychometric performance of group 1 patients was statistically different from that of patients in groups 2 and 3 only in the early follow-up period. CONCLUSIONS Elderly patients having open chamber cardiac operations exhibit significantly more cerebral dysfunction in the early postoperative period than those undergoing major noncardiac operations and younger patients after open chamber procedures. These changes do not persist into the late follow-up period.
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102
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Blake MR, Weimer BC, McMahon DJ, Savello PA. Sensory and Microbial Quality of Milk Processed for Extended Shelf Life by Direct Steam Injection †. J Food Prot 1995; 58:1007-1013. [PMID: 31137408 DOI: 10.4315/0362-028x-58.9.1007] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Heat treatments of milk between 100 and 145°C produce a new type of product with a shelf life of 15 to 30 days at 7°C, which is termed extended shelf life (ESL) milk. Little information is available on the safety and sensory qualities of this product. Extended shelf life milk is being processed commercially to expand the distribution area of fluid milk products. After arrival at market, this product still has the shelf life of a pasteurized product. In this study milk was processed by direct steam injection at temperatures between 100 and 140°C for 4 or 12 s. Holding time did not significantly affect the sensory quality of the milk. A trained taste panel found cooked flavor and other off flavors varied significantly with increasing processing temperature and storage time. There were no significant differences noted in cooked or off flavors between 132 and 140°C. Psychrotrophic Bacillus species were isolated from milk processed at and below 132°C, while no organisms were isolated from milk processed at temperatures at or above 134°C. Consumer preference panels indicated consumers preferred milk processed at 134°C for 4 s to ultrahigh-temperature (UHT) processed milk, although there was a slight preference for high-temperature short-time processed (HTST) milk compared to milk processed at 134°C for 4 s. Higher temperatures had a less destructive effect on lipase activity, while storage time did not significantly affect lipase activity.
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McMahon DJ, Chen S, MacLellan DG. Formal teaching of basic surgical skills. THE AUSTRALIAN AND NEW ZEALAND JOURNAL OF SURGERY 1995; 65:607-9. [PMID: 7661807 DOI: 10.1111/j.1445-2197.1995.tb01707.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Attainment of the practical skills in surgery is an integral part of surgical training. Basic skills must be mastered prior to attempting more complex tasks and bad habits learned early are difficult to correct. A survey of advanced surgical trainees at this hospital demonstrated that skills were usually acquired during sessions in the operating theatre, often in an ad hoc manner. We report our experience in establishing a workshop-based skills course. The program included handling of instruments, knot tying, types and applications of needles and suture materials, wound care, ligation of vessels, and assisting at operation. Following completion of the course and demonstration of their competence, participants were awarded a certificate in basic skills. Participants reported increased confidence and involvement in operative surgery after the course and an increased interest in a career in surgery. We believe the intern year is the most appropriate time to teach such skills, but tuition need not to be restricted to this group. Teaching basic surgical skills in the workshop setting is feasible and advantageous.
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Silverberg SJ, Gartenberg F, Jacobs TP, Shane E, Siris E, Staron RB, McMahon DJ, Bilezikian JP. Increased bone mineral density after parathyroidectomy in primary hyperparathyroidism. J Clin Endocrinol Metab 1995; 80:729-34. [PMID: 7883824 DOI: 10.1210/jcem.80.3.7883824] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Skeletal involvement in primary hyperparathyroidism is characterized by preferential loss of cortical bone, whereas cancellous bone is relatively spared. Little data are available concerning changes in bone density, particularly at sites containing more cancellous bone, after successful parathyroidectomy. Most patients with primary hyperparathyroidism are asymptomatic, but approximately 50% meet one or more criteria for surgery. In a prospective study of 34 patients who met one or more such criteria, bone density rose at all skeletal sites (lumbar spine, femoral neck, and the radius) in the 4 yr after surgery. The lumbar spine, with most cancellous bone, showed a rapid (mean +/- SE, yr 1, 8.2 +/- 2.0%; P < 0.005) and sustained (yr 4, 12.8 +/- 2.8%; P < 0.001) rise. Post-menopausal patients were similar (by yr 4, 12.5 +/- 2.7%; P < 0.005). At the femoral neck, with intermediate cancellous and cortical composition, a similar increase was noted (12.7 +/- 3.8% by yr 4; P < 0.01). The distal radius, containing mostly cortical bone, rose modestly (4.0 +/- 1.5% by yr 3; P < 0.05), except in patients with lowest preoperative bone density, where the increase was marked (12.3 +/- 2.6% by yr 3; P < 0.05). In patients meeting surgical guidelines, parathyroidectomy is associated with improved bone mineral density.
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105
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Benson MC, McMahon DJ, Cooner WH, Olsson CA. An algorithm for prostate cancer detection in a patient population using prostate-specific antigen and prostate-specific antigen density. World J Urol 1993; 11:206-13. [PMID: 7508785 DOI: 10.1007/bf00185070] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Prostate-specific antigen (PSA) is the most accurate serum marker for cancer of the prostate (CaP). However, its sensitivity and specificity are suboptimal, especially at values ranging between 4.1 and 10.0 ng/ml (monoclonal), because benign prostatic hypertrophy and hyperplasia (BPH) and CaP frequently coexist in this range. This study was undertaken to determine the value of incorporating prostate volume measurements with serum PSA levels in a quotient (PSA/volume) entitled PSA density (PSAD). A total of 3140 patients were analyzed and stratified by serum PSA, digital rectal examination (DRE), transrectal prostate ultrasound (TRUS), TRUS volume determination and PSAD. All patients were referred for evaluation and therefore do not represent a screened population. Patients underwent prostate biopsies when abnormalities in TRUS or DRE were detected. Although both PSA and PSAD have statistical significance when the serum PSA value is < or = 4.0 ng/ml, neither has clinical significance in differentiating BPH from CaP. At serum levels ranging between 4.1 and 10.0 ng/ml, PSA has no ability to differentiate BPH from CaP, whereas PSAD does so with statistical and clinical significance. When the PSA value is between 10.1 and 20.0 ng/ml, only PSAD is statistically significant. When PSA exceeds 20 ng/ml, PSAD is redundant. We conclude that all patients with an abnormality on DRE or TRUS should undergo prostate biopsy. If the PSA value is < or = 4.0 ng/ml, TRUS and PSAD are not warranted and routine biopsy is not recommended. For intermediate PSA levels, 4.1-10.0 ng/ml, TRUS, TRUS prostate volume, and PSAD are important.2_
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Zentner PG, Pao LK, Benson MC, McMahon DJ, Schiff PB. Prostate-specific antigen density: a new prognostic indicator for prostate cancer. Int J Radiat Oncol Biol Phys 1993; 27:47-58. [PMID: 7690018 DOI: 10.1016/0360-3016(93)90420-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
PURPOSE Prostate specific antigen density, previously described as a ratio of serum prostate specific antigen to the volume of the prostate, has been shown to be an important factor in the discrimination of patients with occult metastatic disease and patients with benign versus malignant prostatic disease. We undertook a retrospective study to determine if prostate specific antigen density was a predictor of outcome following definitive conformal radiation therapy. METHODS AND MATERIALS Between January 1989 and August 1991, 86 patients with localized prostate cancer (confined to the prostate, periprostatic tissue, or seminal vesicles) were treated in the Department of Radiation Oncology, Columbia-Presbyterian Medical Center with definitive radiation therapy using computed tomography-guided conformal technique. Thirteen patients were excluded on the basis of prior prostatectomy, hormonal therapy, or no pretreatment prostate specific antigen measurement. Seventy-three patients were evaluable: 19% (14/73) American Urologic Association Stage A (T1), 41% (30/73) B (T2), and 40% (29/73) C (T3). Prostate specific antigen density was defined as the ratio of the pretreatment serum prostate specific antigen to the prostate volume as determined from computed tomography treatment planning scans. Pretreatment prostate specific antigen density was calculated for each patient and ranged from 0.04-3.85 with a mean and median value of 0.66 and 0.33, respectively. Prostate specific antigen failure was defined as a rise above normal level or, for patients whose nadir was above 4 ng/ml, an increase of greater than 10% above nadir. Mean prostate specific antigen follow-up was 13 months (range 2.3-31 months) by which time 66% of patients had normal prostate specific antigen (< or = 4 ng/ml) levels. RESULTS Nine patients experienced prostate specific antigen failure. The mean prostate specific antigen density of patients with disease-free survival versus failures was 0.53 and 1.6, respectively (p < 0.05). Kaplan-Meier analysis showed that patients with a prostate specific antigen density < or = 0.3 (n = 30) had 100% actuarial disease-free survival at 30 months compared with 62% for patients with prostate specific antigen density > 0.3 (n = 43, p < 0.01). Patients with a prostate specific antigen density < or = 0.6 (n = 52) and > 0.6 (n = 21) had an 88% and 57% actuarial disease-free survival at > 24 months (p < 0.05). CONCLUSION Prostate specific antigen density was an excellent predictor of disease-free survival (p < 0.01) and was superior to clinical stage (p > 0.05), Gleason's score (p > 0.05), and pretreatment prostate specific antigen (p < 0.05). These results suggest that patients with low prostate specific antigen density (< or = 0.3), including those with locally advanced clinical stage, high Gleason's score, or elevated pretreatment prostate specific antigen, do well with conventional radiation therapy and should not be subjected to high risk protocols. Further follow-up will be required to determine if patients with low prostate specific antigen density will have improved overall survival.
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107
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Venkatachalam N, McMahon DJ, Savello PA. Role of protein and lactose interactions in the age gelation of ultra-high temperature processed concentrated skim milk. J Dairy Sci 1993; 76:1882-94. [PMID: 8345125 DOI: 10.3168/jds.s0022-0302(93)77521-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Skim milk was pasteurized, diafiltered, and concentrated three times by UF. Lactose or sucrose was then added at 3 or 6%. The five samples containing < .05% lactose, 3 and 6% lactose, and 3 and 6% sucrose were UHT processed at 140 degrees C for 4 s using indirect heating, collected aseptically in presterilized containers, and stored at 4, 20, and 35 degrees C. All samples stored at 4 and 20 degrees C gelled after 21 wk of storage. Samples stored at 35 degrees C did not gel. Browning occurred only in samples containing lactose stored at 35 degrees C. Proteolysis in gelled samples was shown by SDS-PAGE. Bands were due to proteolysis, protein crosslinking, and a streaking pattern in ungelled samples. Electron micrographs of gelled samples showed that various casein particles were connected by hairlike protrusions, but the micelles in ungelled samples were not connected and had few protrusions. The Maillard reaction neither promoted nor deferred age gelation. Protein modifications prevented gelation in samples stored at 35 degrees C. Age gelation was probably a two-step process in which dissociated proteins from the casein micelles reformed on micelles as hairlike protrusions. This process was followed by aggregation of the protein particles.
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108
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el-Samragy YA, Hansen CL, McMahon DJ. Production of ultrafiltered skim milk retentate powder. 1. Composition and physical properties. J Dairy Sci 1993; 76:388-92. [PMID: 8445091 DOI: 10.3168/jds.s0022-0302(93)77357-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Raw skim milk retentate with 20% solids produced by UF was subjected to different heat treatments and pH adjustments prior to spray-drying. The heat treatments were 65 degrees C for 30 min, 75 degrees C for 28 s, and 85 degrees C for 28 s. pH was adjusted to 6.4, 6.7, and 7.0. Retentate powders were analyzed for moisture, protein, lactose, fat, ash, titratable acidity, and pH. Physical property determinations included solubility index, dispersibility, viscosity, scorched particles, poured density, packed density, and water absorption isotherm. No interaction effects of heat treatment and pH adjustment were observed. pH adjustments affected ash content and solution viscosity. Heat treatment affected solubility and poured density. pH adjustments and heat treatment had only minor effects on the measured properties.
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109
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Fulmer T, McMahon DJ, Baer-Hines M, Forget B. Abuse, neglect, abandonment, violence, and exploitation: an analysis of all elderly patients seen in one emergency department during a six-month period. J Emerg Nurs 1992; 18:505-10. [PMID: 1469815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Vulnerable individuals in society seem to be even more vulnerable as they age. Our data suggest that during the next decade members of our aging society may well tax our adult protective service systems to a greater degree than heretofore imagined. We have an opportunity to be proactive in this regard.
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110
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Hekmat S, McMahon DJ. Survival of Lactobacillus acidophilus and Bifidobacterium bifidum in ice cream for use as a probiotic food. J Dairy Sci 1992; 75:1415-22. [PMID: 1500547 DOI: 10.3168/jds.s0022-0302(92)77895-3] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Probiotic ice cream was made by fermenting a standard ice cream mix with Lactobacillus acidophilus and Bifidobacterium bifidum cultures and then freezing the mix in a batch freezer. Survival of the L. acidophilus and B. bifidum, as well as beta-galactosidase activity, was monitored during 17 wk of frozen storage at -29 degrees C. After freezing of the fermented mix, bacterial counts were 1.5 x 10(8) cfu/ml for L. acidophilus and 2.5 x 10(8) cfu/ml for B. bifidum. Seventeen weeks after freezing, these counts had decreased to 4 x 10(6) and 1 x 10(7) cfu/ml, respectively. During the same period, beta-galactosidase activity decreased from 1800 to 1300 units/ml. Probiotic ice cream was prepared at pH 5.0, 5.5, and 6.0 to determine consumer preferences and was compared with standard Utah State University "Aggie" ice cream. All samples were strawberry-flavored and were evaluated by 88 judges. The preferred pH of probiotic ice cream, based on overall acceptance, was pH 5.5. We demonstrated that probiotic ice cream is a suitable vehicle for delivering beneficial microorganisms such as L. acidophilus and B. bifidum to consumers. The bacteria can be grown to high numbers in ice cream mix and remain viable during frozen storage.
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111
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Shammet KM, Brown RJ, McMahon DJ. Proteolytic activity of proteinases on macropeptide isolated from kappa-casein. J Dairy Sci 1992; 75:1380-8. [PMID: 1500545 DOI: 10.3168/jds.s0022-0302(92)77890-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Proteolytic activities of chymosin, bovine pepsin, Mucor miehei rennet, Cryphonectria parasitica (formerly Endothia parasitica) rennet, trypsin, and chymotrypsin on kappa-casein macropeptide were measured. Macropeptide solutions (10 mg/ml of .05 M, pH 6.6 phosphate buffer) were incubated with the enzymes at 37 degrees C for various times, and their reactions were stopped by adding .025 ml of pepstatin (1 mg/ml of methanol). Peptides released from kappa-casein macropeptide were then fractionated using reverse-phase HPLC. At the pH of milk (pH 6.6), kappa-casein macropeptide was resistant to enzymic action by chymosin, bovine pepsin, and M. miehei and C. parasitica rennets. Bovine pepsin hydrolyzed kappa-casein macropeptide at pH 3. kappa-Casein macropeptide was readily hydrolyzed at pH 6.6 by trypsin and chymotrypsin. Possible physiological functions of the kappa-casein macropeptide are discussed in light of these findings.
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112
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Benson MC, Whang IS, Olsson CA, McMahon DJ, Cooner WH. The use of prostate specific antigen density to enhance the predictive value of intermediate levels of serum prostate specific antigen. J Urol 1992; 147:817-21. [PMID: 1371555 DOI: 10.1016/s0022-5347(17)37394-9] [Citation(s) in RCA: 448] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Prostate specific antigen (PSA) is an extremely valuable tumor marker. However, its use in detection is limited by its low positive and negative predictive values. The ability of serum PSA to distinguish between benign and malignant prostatic conditions is particularly poor in the intermediate range of 4.1 and 10 ng./ml. by the Hybritech assay. We used transrectal ultrasound determined prostate volumes in a well characterized population of 533 men to form a serum PSA/prostate volume ratio called prostate specific antigen density (PSAD). The prevalence of cancer in the entire population was 18.4%. Discriminant analysis according to negative or positive outcome allowed for the construction of nomograms, which resulted in a PSAD defined cancer risk ranging from 3 to 100%. Predictive value nomograms created from PSAD may allow for a more individualized approach to evaluation of patients with intermediate levels of Hybritech serum PSA.
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Barr AE, Diamond BE, Wade CK, Harashima T, Pecorella WA, Potts CC, Rosenthal H, Fleiss JL, McMahon DJ. Reliability of testing measures in Duchenne or Becker muscular dystrophy. Arch Phys Med Rehabil 1991; 72:315-9. [PMID: 2009048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In a multiinstitutional collaborative study, we ascertained the interevaluator and intraevaluator reliability of six physical therapists who performed assessment measures on 36 boys (11.7 +/- 3.9 years) with Duchenne or Becker muscular dystrophy. Upper and lower extremities were evaluated by manual muscle testing for function, range of motion, and strength. The data were analyzed using intraclass correlation coefficients (ICCs). For the interevaluator phase, ICCs were as follows: average muscle strength, .90; range of motion, .76; and upper extremity functional performance, .58. For the intraevaluator phase, corresponding ICCs were .80 to .96; .33 to .97; .34 to 1.00. Our results confirm and extend observations by others that these assessment measures are sufficiently reliable for use in a multiinstitutional collaborative effort. Such results can be used to design clinical trials that have sufficient statistical power to detect changes in the rate of disease progression. Investigators planning clinical trials in a multiinstitutional collaborative setting should first standardize the assessment methods, provide evaluator training, and document reliability.
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McMahon DJ, Carpenter RL. A comparison of conductivity-based hematocrit determinations with conventional laboratory methods in autologous blood transfusions. Anesth Analg 1990; 71:541-4. [PMID: 2221416 DOI: 10.1213/00000539-199011000-00015] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
An investigation was made of the accuracy of a portable hematocrit measurement device (Stat-Crit) on the infusate of an autologous blood transfusion system. Baseline hematocrit values were determined by three methods on in vivo blood samples of surgical patients immediately after the start of surgery, and again on the first product of the autologous blood retrieval system. At baseline, there were no significant differences in the values determined by the Stat-Crit (33.4% +/- 6.2%, mean +/- SD) and those determined by the microcentrifuge technique (33.8% +/- 4.7%) or by the Coulter method (33.5% +/- 4.5%) (P = 0.9). In contrast, hematocrit values determined on infusate samples by the Stat-Crit (36.6% +/- 4.8%) were significantly lower than those determined by the microcentrifuge technique (51.2% +/- 5.9%) or by the Coulter method (51.6% +/- 5.8%) (P = 0.0001). This study confirms close agreement of hematocrit values derived by the conductivity of whole blood in normal samples with those determined by conventional laboratory techniques, but indicates that this method will report falsely low readings in situations where plasma has been replaced by crystalloid, as in patients who have received large transfusions of processed autologous blood.
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McMahon DJ, Thompson GE. A survey of anesthesia support personnel in teaching programs. MEDICAL INSTRUMENTATION 1987; 21:269-74. [PMID: 3683253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Although the amount and complexity of equipment and supplies used in the practice of anesthesia have sharply increased in the past decade, the role of technical support personnel dealing with this technology has not been assessed. In an effort to determine that role, a questionnaire survey was conducted of the apportionment, direction, duties, and training of anesthesia technicians in teaching departments. Two-thirds of the inquiries were returned, disclosing a typical allocation of three anesthetizing locations (or 2000 annual anesthetics) per technician. A large majority of these departments have direct control of their technicians. Virtually all of these personnel are responsible for the routine upkeep and setup of anesthesia machines and monitors, although about one-third perform more specialized clinical functions. The preparation of these technicians for their duties varies widely, with almost 60% high school graduates and virtually all reporting training as on-the-job. The authors conclude that the term "anesthesia technician" remains poorly defined and unstandardized, and that current diverse efforts to address this issue deserve attention.
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118
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Crawford JL, McMahon DJ, Conklin GS, Giordano D, Alexander MJ, Kadyszewski P. Assessing skilled functioning of mentally retarded persons. MENTAL RETARDATION 1980; 18:235-9. [PMID: 7242358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Abstract
Five cases of spontaneous pneumomediastinum are presented. This is a benign condition that requires no specific therapy.
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120
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McMahon DJ, Manring ER, Patty RR. Photometer for detection of sodium day airglow. APPLIED OPTICS 1973; 12:1806-1810. [PMID: 20125610 DOI: 10.1364/ao.12.001806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Daytime, ground based measurements of sodium airglow emission are particularly difficult to perform. The ratio of airglow signal to Rayleigh and Mie scattering by the atmosphere as well as the very pronounced Fraunhofer structure lead to extraneous signals that are difficult to evaluate and require specialized techniques to eliminate. The photometer described can be characterized by the following principal features: (1) a narrow (4.5-A) interference filter for initial discrimination; (2) cooled photomultiplier detector to reduce noise from dark current fluctuations and chopping to eliminate the average dark current; (3) a sodium vapor resonance cell to provide an effective bandpass comparable to the Doppler line width; (4) separate detection of all light transmitted by the interference filter to evaluate the Rayleigh and Mie components within the Doppler width of the resonance cell; (5) temperature quenching of the resonance cell to evaluate and account for instrumental imperfections.
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McMahon DJ. Annular pancreas--a case report. JAMA 1969; 207:756. [PMID: 5818199 DOI: 10.1001/jama.207.4.756b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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122
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Möller KD, McMahon DJ, Smith DR. Far infrared transmission filters for the 300-18 cm (-1) spectral region. APPLIED OPTICS 1966; 5:403-406. [PMID: 20048862 DOI: 10.1364/ao.5.000403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A simplified method for the fabrication of crystal powder transmission filters is reported. Transmission filter combinations are described for the 300-18 cm(-1) spectral region. The application of these filters in a small grating spectrometer is demonstrated by water vapor spectra.
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