How and why we need to capture tacit knowledge in manufacturing: Case studies of visual inspection.

Human visual inspection skills remain superior for ensuring product quality and conformance to standards in the manufacturing industry. However, at present these skills cannot be formally shared with other workers or used to develop and implement new solutions or assistive technologies because they involve a high level of tacit knowledge which only exists in skilled operators' internal cognitions. Industry needs reliable methods for the capture and analysis of this tacit knowledge so that it can be shared and not lost but also so that it can be best utilised in the transfer of manual work to automated systems and introduction of new technologies and processes. This paper describes two UK manufacturing case studies that applied systematic task analysis methods to capture and scrutinise the tacit knowledge and skills being applied in the visual inspection of aerospace components. Results reveal that the method was effective in eliciting tacit knowledge, and showed that tacit skills are particularly needed when visual inspection standards lack specification or the task requires greater subjective interpretation. The implications of these findings for future research and for developments in the manufacturing industry are discussed.

Fixed film phosphorus removal--flexible enough?

While biological phosphorus removal (BPR) has been practised for 30 years, up to recently it has been restricted mainly to activated sludge processes, with the corresponding need for large basin volumes. Yet, research with biofilm reactors showed that the principle of alternate anaerobic and aerated conditions was applicable to fixed bacteria by changing the conditions in time rather than in space. Attached growth enhanced biological phosphorus removal (EBPR) systems are attractive because of their compactness and capability to retain high biomass levels. However, the phosphorus extraction depends on backwashes to enhance the phosphorus-rich attached biomass, and correct control of unsteady effluent quality created by frequently modified process conditions. Accordingly, EBPR remains a challenging task in terms of combining nitrogen and phosphorus removal using attached growth systems. Nevertheless, a combination of activated sludge and biofilm carriers, in the integrated fixed-film activated sludge system, provides treatment opportunities not readily available using suspended growth systems. Current practice is only at the beginning of exploiting the full potential of this combination, but the first full-scale results show that compact tankage and low nutrient results based on biological principles are possible.

Habitat Suitability Model for the Distribution of Ixodes scapularis (Acari: Ixodidae) in Minnesota.

Ixodes scapularis Say, the black-legged tick, is the primary vector in the eastern United States of several pathogens causing human diseases including Lyme disease, anaplasmosis, and babesiosis. Over the past two decades, I. scapularis-borne diseases have increased in incidence as well as geographic distribution. Lyme disease exists in two major foci in the United States, one encompassing northeastern states and the other in the Upper Midwest. Minnesota represents a state with an appreciable increase in counties reporting I. scapularis-borne illnesses, suggesting geographic expansion of vector populations in recent years. Recent tick distribution records support this assumption. Here, we used those records to create a fine resolution, subcounty-level distribution model for I. scapularis using variable response curves in addition to tests of variable importance. The model identified 19% of Minnesota as potentially suitable for establishment of the tick and indicated with high accuracy (AUC = 0.863) that the distribution is driven by land cover type, summer precipitation, maximum summer temperatures, and annual temperature variation. We provide updated records of established populations near the northwestern species range limit and present a model that increases our understanding of the potential distribution of I. scapularis in Minnesota.

Candida hepatitis. Histopathologic diagnosis.

Candida hepatitis, usually a manifestation of disseminated candidiasis in immunocompromised patients, is difficult to diagnose antemortem. We studied six patients with proven hepatic candidiasis to assess features helpful in deriving a correct diagnosis. Five patients were immunosuppressed as a result for treatment for leukemia; one was immunosuppressed due to renal transplantation. All had sustained fevers greater than 101 degrees F, elevated alkaline phosphatase levels, and multiple hepatic and splenic defects--presumably abscesses--on abdominal CT scan. Twelve liver biopsies (nine needle, three wedge) were examined. Biopsies from four patients contained identifiable Candida organisms within suppurative granulomas; a biopsy from a fifth patient grew Candida albicans in cultures. In the sixth patient, the first biopsy was culture positive for Candida albicans, and the second biopsy, a fine-needle aspirate, contained Candida organisms and purulent material. In all of the nondiagnostic biopsies, as well as in regions of the diagnostic biopsies around the suppurative granulomas, mass-associated obstructive changes were noted. These included pericentral sinusoidal dilatation and cholestatic inflammation characterized by periportal ductular proliferation with surrounding neutrophils and edema. We conclude that in the appropriate clinical setting, these mass-associated histologic findings are suggestive of adjacent Candida abscesses. Definite diagnosis requires either the identification of Candida organisms within inflammatory hepatic lesions or positive culture of Candida from the liver biopsy.

Prognostic implications of the tall cell variant of papillary thyroid carcinoma.

The tall cell variant (TCV) of papillary thyroid carcinoma, characterized by a population of tall columnar cells with a height at least twice the width, was analyzed in 12 patients and compared to tumors from 12 patients with the usual type of papillary thyroid carcinoma (UPTC) matched for age, sex, and date of diagnosis to determine if tall cell histology had prognostic significance. Patients with TCV had significantly higher incidences of extrathyroidal disease, recurrent disease, and metastases compared to patients with UPTC. TCV patients also died of their tumors more frequently than UPTC patients (3/12 versus 0/12). There was no significant difference in tumor size or in the incidence of cervical lymph node involvement between the patient groups. These results show that TCV of papillary thyroid carcinoma has a more aggressive clinical course and a worse prognosis than UPTC in patient groups with similar age and sex distribution, length of follow-up, and tumor size.

Cardiac paragangliomas. A clinicopathologic and immunohistochemical study of four cases.

Cardiac paragangliomas are extremely rare neoplasms. Four surgically resected tumors were examined by immunohistochemistry and electron microscopy. The patients ranged in age from 18 to 36 years. All patients had hypertension and elevated urine catecholamine levels. Three tumors were located on the posterior left atrium, and one tumor was located in the interventricular groove at the aortic root. The tumors ranged in size from 5 to 7 cm, and they displayed a prominent Zellballen pattern without significant necrosis or mitosis. The tumors were mostly unencapsulated and infiltrated adjacent cardiac tissue in two cases. Immunoperoxidase staining showed that all tumors were positive for chromogranin and neuron-specific enolase. Three tumors were positive for methionine enkephalin. Positive staining for S-100 protein was seen in the sustentacular cells of all tumors but was negative in chromaffin cells. All tumors were negative for insulin, glucagon, gastrin, vasoactive intestinal polypeptide, somatostatin, adrenocorticotropic hormone, calcitonin, serotonin, pancreatic polypeptide, and rat atrial peptide. Ultrastructural studies of all four tumors showed moderate numbers of predominantly norepinephrine-type granules and a few epinephrine-type granules. These results show that cardiac paragangliomas are commonly found in close proximity to the left atrium and have immunohistochemical and ultrastructural features similar to other paragangliomas.

Structure-activity relationships of the antimalarial agent artemisinin. 5. Analogs of 10-deoxoartemisinin substituted at C-3 and C-9.

Novel 3- and 9-substituted analogs (4-19) of 10-deoxoartemisinin, 3, were prepared from the corresponding known lactones by one-pot reduction with sodium borohydride and boron trifluoride etherate. Reproducibility problems associated with this heterogeneous reaction were encountered on small reaction scales, and thus alternative methodology was sought for this reduction. Conversion of the lactones to tetrahydropyrans via the corresponding intermediate lactols was made more reproducible using a two-step sequence involving low-temperature reduction with diisobutylaluminum hydride followed by deoxygenation with boron trifluoride etherate in the presence of triethylsilane. In this manner, 10-deoxoartemisinin (3) could be obtained from artemisinin (1) in greater than 95% overall yield. All analogs were tested in vitro against W-2 and D-6 strains of Plasmodium falciparum. Several of the analogs were much more active than the natural product (+)-artemisinin (1) or 10-deoxoartemisinin (3). Conventional structure-activity relationships are discussed in relation to the bioassay data.

Worsening tricuspid regurgitation following pericardiectomy for constrictive pericarditis.

We describe two cases of worsening tricuspid regurgitation following surgical pericardiectomy for constrictive pericarditis. Both patients demonstrated hemodynamic profiles characteristic of constrictive pericarditis on cardiac catheterization. They also had moderate tricuspid regurgitation as judged by Doppler echocardiography. The worsening tricuspid regurgitation observed was a result of postoperative right ventricular dilatation. These cases demonstrate the importance of determining tricuspid valvular function in patients with constrictive pericarditis prior to pericardiectomy; however, the hemodynamic changes that result in worsening tricuspid regurgitation may not be present for weeks.

Rapid method of MIC determinations utilizing tetrazolium reduction.

A rapid preliminary method of determining antibiotic susceptibilities of clinically isolated gram-negative fermentative organisms has been evaluated. The method utilizes tetrazolium dye reduction as a colorimetric indicator of bacterial growth. Tetrazolium dye reduction is incorporated into the standard Micro-Media MIC microdilution testing system and shortens the required incubation period from 15 to 18 hours to 4 hours. Parallel MIC determinations were made by the standard MIC method and by the rapid tetrazolium method. The test organisms included 218 gram-negative fermentative clinical isolates. The overall correlation between the standard and the rapid MIC methods was 93%. Of the 7% discordant results, 6.3% represented minor discrepancies and 0.7% represented major discrepancies. There were no very major discrepancies. The study concluded that the rapid tetrazolium MIC method is an accurate, low-cost, easily implemented method of preliminary antibiotic susceptibility testing for gram-negative fermentative organisms.

Effects of organotins on rat platelets.

Incubation of rat platelets with organotins inhibited their capacity to take up 5-hydroxytryptamine-14C (5-HT-14C) and stimulated the release of preloaded 5-HT-14C as well as endogenous 5-HT. Similar but less pronounced effects also were observed when platelets from rats treated intraperitoneally with organotins were examined. The relationships of organotin structure to 5-HT uptake inhibition and 5-HT release were similar, with the most active compounds being the trisubstituted derivatives bis(tri-n-butyltin) oxide, tri-n-butyltin chloride, tricyclohexyltin hydroxide, tri-n-propyltin chloride, and triphenyltin hydroxide. Scanning electron micrographs revealed increased platelet aggregation and shape change in organotin treated samples as compared to vehicle treated controls. It was suggested that the action of organotins on rat platelets was due, at least in part, to their known ability to interfere with ATPase mediated systems.

Effect of formamidines on 5-hydroxytryptamine uptake and biogenic amine levels in rat platelets.

Uptake of radioactive 5-hydroxytryptamine (5-HT) by platelets from rats treated intraperitoneally with the insecticide/acaricide chlordimeform (CDF) at 25 mg/kg was not significantly influenced at 1 h; however, uptake of this amine by platelets from rats treated with its N- monodemethyl metabolite (DMC) at the same dosage was significantly inhibited (37%). Two reversed phase high performance liquid chromatographic systems with electrochemical detection were developed with a capacity to separate 11 biogenic amines and related compounds. Only 5-HT, norepinephrine (NE), dopamine (DA), and 3,4-dihydroxyphenylacetic acid (DOPAC) were consistently detected in platelets and plasma samples. At 1 h and/or 24 h postinjection, CDF effected significant decreases in platelet levels of 5-HT, NE, and DA and plasma levels of 5-HT, whereas platelet and plasma levels of DOPAC were significantly increased. DMC effected significant decreases in both platelet and plasma levels of 5-HT. These in vivo studies confirmed previous in vitro experiments which demonstrated that formamidines inhibited uptake of 5-HT by platelets and released endogenous stores of amines from platelets.

Skeletal muscle following tonic overload: functional and structural analysis.

Functional overloading of skeletal muscle induces a compensatory hypertrophy as an adaptive response to increased functional demand. Overload of the extensor digitorum longus (EDL) muscle (129 ReJ strain male mouse) was induced by unilateral surgical removal of a synergistic muscle, tibialis anterior (TA). Response of the EDL to overload for 7, 21, and 42 d was analyzed for changes in 1) muscle weight, 2) myofiber type distribution, 3) myofiber cross-sectional area by fiber type, 4) speed of contraction and relaxation of the muscle, 5) force of contraction, and 6) myofiber morphologic integrity. The weight of the EDL significantly increased. The overload caused no impairment of muscle contractility and did not have a significant effect on isometric twitch contraction time to peak tension or the time to one-half relaxation of the twitch. Overloaded muscles demonstrated a transient shift in fiber type profile with preferential hypertrophy of Type IIA fibers that occurred in the early phase of overload while type IIB fibers were recruited by 42 d. No significant increase in myofiber number in overloaded muscles occurred. Some morphologic changes in over-loaded muscles parallel those found in patients with neurogenic muscular disorders. However, overloaded muscle did not exhibit a significant occurrence of fiber branching from controls in the midbelly region of the muscle.

Update on the surgical pathology of the vulva.

Recent developments in the surgical pathology of the vulva include updated classifications of non-neoplastic epithelial disorders and vulvar intraepithelial neoplasias. Several histologic variants of vulvar squamous cell carcinoma (SCC) with distinct clinicopathologic features have been described. The concept of superficially invasive vulvar SCC continues to be a complex issue. The use of standardized surgical pathology reports and checklists are recent developments in surgical pathology.

Inhibition of rat platelet 5-hydroxytryptamine uptake by chlordimeform.

Chlordimeform, a formamidine insecticide and acaricide, and two of its toxic N-demethyl metabolites inhibited rat blood platelet 5-hydroxytryptamine (5-HT) uptake. A direct relationship existed between formamidine uptake inhibitory potency and N-demethylation. Didemethylchlordimeform, the most potent formamidine inhibitor of 5-HT uptake examined, had a pI50 of 4.2. However, it was appreciably less active than the classical inhibitor imipramine, which yielded 86.4% inhibition of 5-HT uptake at a concentration of 1.10(-5) M.

G8363A mutation in the mitochondrial DNA transfer ribonucleic acidLys gene: another cause of Leigh syndrome.

We identified a G-->A transition at nt-8363 in the mitochondrial DNA transfer ribonucleic acidLys gene in blood and muscle from a 13-month-old girl who had clinical and neuroradiologic evidence of Leigh syndrome and died at age 27 months. The mutation was less abundant in the same tissues from the patient's mother, who developed myoclonus epilepsy with ragged red fibers (MERRF) in her late 20s. In both mother and daughter, muscle histochemistry showed ragged red and cytochrome c oxidase-negative fibers and biochemical analysis showed partial defects of multiple respiratory-chain enzymes. A maternal half-sister of the proband had died at 2.5 years of age from neuropathologically proven Leigh syndrome. The G8363A mutation, which previously had been associated with cardiomyopathy and hearing loss, MERRF, and multiple lipomas, also should be included in the differential diagnosis of maternally inherited Leigh syndrome.

Indirect immunofluorescence technique to detect monoclonal antinuclear antibody.

Monoclonal proteins directed against nuclear antigens are extremely rare. We describe the use of a double antibody immunofluorescence technique to document the existence of a monoclonal antibody with nuclear antigen activity. The patient was an elderly woman with a small monoclonal protein, but no evidence of a lymphoproliferative or autoimmune disorder. A homogeneous antinuclear antibody (ANA) prompted further studies to determine whether the monoclonal protein was related to the ANA activity. A double-antibody immunofluorescence procedure is described by which the ANA positivity was shown to be entirely due to a monoclonal IgMK protein. It consists of using fluorescein anti-kappa and rhodamine anti-lambda applied to a section of mouse kidney treated with the patient's serum. Documentation of antigenic specificity of monoclonal antibodies by double antibody fluorescence provides a straightforward method that can be utilized by routine clinical laboratories.

Attention to auditory and peripheral visual stimuli: effects of arousal and predictability.

Changes in the distribution of attention among auditory and peripheral visual stimuli were examined in a choice reaction time paradigm. Two variables were manipulated: predictability of stimulus locations and arousal state of subjects. The arousal level of some subjects was raised by occasionally exposing them to brief, mild electric shocks. On most trials either a tone or a light was presented alone (single-stimulus trials). However, on 20% of the trials both a tone and light were presented simultaneously (dual trials). Two dependent variables were used to assess dominance of attention: reaction time (on all trials) and percentage of time each modality was chosen on dual trials. Neither modality was dominant when subjects were in a nonaroused state and stimulus locations were unpredictable. However, peripheral vision dominated when stimulus locations were predictable or when the subjects' level of arousal was raised. The results are discussed with reference to previous research on sensory dominance and on the facilitating or inhibiting effects of auditory stimuli on reaction time.

Lymphangioma circumscriptum of the vulva. A report of two cases.

Lymphangioma circumscriptum is an uncommon dermatologic problem that only rarely affects the vulva. It is considered to be a circumscribed developmental defect of lymphatic tissue in the dermis. We encountered two patients whose clinical manifestations required management with extensive vulvar surgery. These cases illustrate the spectrum of presentation of this disorder and its treatment.

Cytologic features of collagenous spherulosis of the breast.

Collagenous spherulosis is generally classified as a component of benign proliferative breast disease. Previous reports have described the histologic features of collagenous spherulosis, but we are unaware of cytologic descriptions of the condition. In this report, the cytologic features of collagenous spherulosis are described and the differential diagnosis is discussed.

Cytologic features of metastatic transitional cell carcinoma.

Cytologic preparations containing metastatic transitional cell carcinoma (MTCC) from 18 sites in 16 patients were reviewed to determine characteristic morphologic features. The patient group included 13 males and 3 females with a mean age of 66 years. Primary TCC occurred in the bladder (14), kidney (1), and ureter (1); nearly all the primary tumors were poorly differentiated and most were invasive at the time of diagnosis. The cytologic specimens were derived from lymph nodes (6), liver (4), serous fluids (2), pelvic soft tissue (2), subcutaneous nodules (2), and lung (1). One patient presented with MTCC in Pap smears. Cytologically MTCC presented as loosely cohesive, moderate to markedly pleomorphic cells which occurred singly and in syncytial clusters. The malignant cells were usually large with abundant granular or fibrillar cytoplasm and the cell borders were generally distinct. Most nuclei were large and hyperchromatic with irregularly distributed granular chromatin and prominent nucleoli. The most distinctive features were the presence of spindled, pyramidal, and/or racquet-shaped malignant cells with eccentric nuclei and cytoplasmic features of both squamous and glandular differentiation including endoplasmic/ectoplasmic interfaces and intracytoplasmic vacuoles. Although clinical history is most useful in the diagnosis of MTCC, these morphologic features in cytologic preparations of malignant epithelial neoplasms may be helpful. In the absence of a known primary TCC, it is doubtful that a definite cytologic diagnosis could be made; however, the characteristic cell shapes and cytoplasmic features may be suggestive of MTCC.