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  • 1
    Electronic Resource
    Electronic Resource
    Atomic scale friction of a diamond tip on diamond (100) and (111) surfaces (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 163-167 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The friction of a clean diamond tip on diamond (111) and (100) surfaces is studied using an ultrahigh vacuum force microscope that simultaneously measures forces parallel and perpendicular to the surface. The 30 nm radius diamond tip is fabricated by chemical vapor deposition. The attractive normal force curve between the tip and surface agrees well with calculated dispersion interactions. The frictional force exhibits periodic features, which on the (100) surface are tentatively associated with a 2×1 reconstructed surface convoluted over an asymmetric tip shape. The (111) surface shows features that cannot be simply related to the surface structure. As the tip is scanned back and forth along a line, the same features are observed in each direction, but offset, suggesting the presence of a conservative force independent of the direction of motion as well as a nonconservative force. The friction is approximately (approximately-equal-to)3×10−9 N independent of loads up to 1×10−7 N.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353878
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  • 2
    Electronic Resource
    Electronic Resource
    A micropipette force probe suitable for near-field scanning optical microscopy (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 4061-4065 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In this paper it is demonstrated that glass micropipettes have unique applicability as force probes for a variety of imaging conditions and a variety of scanned tip microscopies. These probes are characterized in terms of the parameters that determine their force characteristics. Measurements are presented showing that one can readily achieve force constants of 10 N/m and it is anticipated that a reduction in this force constant by two orders of magnitude can be achieved. Such probes can be produced simply with a variety of geometries that permit a wide range of force imaging requirements to be met. Specifically, the glass micropipette probes reported in this paper are readily produced with apertures at the tip and can thus be applied to near-field scanning optical microscopy (NSOM). This opens the possibility of the long-awaited development of a universal feedback mechanism for NSOM.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1143212
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  • 3
    Electronic Resource
    Electronic Resource
    Multifunctional, micropipette based force cantilevers for scanned probe microscopy (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 65 (1994), S. 648-650 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We demonstrate quartz micropipette and optical fiber based structures with unique applications for scanned probe microscopy. These probes are produced by drawing, cantilevering, and polishing tapered micropipettes and optical fibers and have significantly greater potential functionality than any other currently available scanning tip. We present normal force, contact mode imaging of a selection of surfaces, operating these probes with different commercial instruments for atomic force microscopy (AFM). With their very sharp tips, ultrahigh aspect ratios, and readily adjustable force constants and resonance frequencies, the probes present an attractive alternative to conventional microfabricated cantilevers that are currently in routine use with AFM. Bent quartz optical fiber probes also enable simple integration of near-field scanning optical microscopy and AFM.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.112259
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  • 4
    Electronic Resource
    Electronic Resource
    Force microscopy with a bidirectional capacitance sensor (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 2296-2308 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new method for sensing cantilever deflection in the atomic force microscope (AFM), based on capacitance measurement, is described. Parameters governing the design of such an instrument are considered in detail. Two different geometries are compared, wire on plate and an integrated flat plate sensor. The electronic circuitry, providing 6×10−19 F noise in a 0.01–1000 Hz bandwidth, is also described. Implementation of the design ideas into a working AFM in ultrahigh vacuum is demonstrated. This AFM allows simultaneous measurement of cantilever deflection in two orthogonal directions, necessary for our nanotribology studies. The theoretical sensitivity of 5×10−7 F/m is not achieved due to roughness. The bidirectional sensing and imaging capabilities are demonstrated for an Ir tip on cleaved graphite, and a diamond tip on diamond films. The capacitance detection technique is compared and contrasted with other AFM sensors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141354
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  • 5
    Electronic Resource
    Electronic Resource
    Malignancy-induced secondary achalasia (1993)
    Springer
    Dysphagia 8 (1993), S. 292-296 
    Details
    ISSN: 1432-0460
    Keywords: Achalasia ; Pseudoachalasia ; Esophageal manometry ; Esophageal aperistalsis ; Deglutition ; Deglutition disorders
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Secondary achalasia refers to the development of clinical, radiographic, and manometric findings of achalasia as a result of (i.e., secondary to) another underlying disorder. A variety of malignancies have been associated with secondary achalasia. Adenocarcinoma of the esophagogastric junction accounts for the majority of cases of malignancy-induced achalasia, however, noncontiguous tumors may also cause this disorder. Although rare, malignancy-induced achalasia will occasionally be encountered by gastroenterologists and gastrointestinal radiologists who see patients with dysphagia and/or achalasia. Since treatment is aimed at the underlying neoplasm, it is important to recognize this disorder. Three clinical features suggest the possibility of malignancy as a cause of achalasia: 1) short duration of dysphagia (〈1 year); 2) significant weight loss (〉15 pounds); and 3) age 〉55 years. The presence of any of these should at least raise a suspicion of malignancy. Diagnosis may not be evident on routine esophagrams and endoscopy, and requires clinical suspicion for further evaluation with thoraco-abdominal CT scanning and endoscopic ultrasonography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01354553
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  • 6
    Electronic Resource
    Electronic Resource
    Localization of epitopes for antibodies that differentially label sodium channels in skeletal muscle surface and T-tubular membranes (1992)
    Springer
    The journal of membrane biology 128 (1992), S. 219-226 
    Details
    ISSN: 1432-1424
    Keywords: ion channels ; channel subtypes ; epitope localization ; sarcolemma ; monoclonal antibodies ; radioimmunoassay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary We previously characterized two monoclonal antibodies, A/B2 and L/D3, that bind to the amino-terminus of the sodium channel but produce distinct immunocytochemical patterns in innervated adult skeletal muscle. Because these findings suggested the presence of several channel isoforms, we sought to define the epitopes for each antibody. Five peptides encompassing the amino-terminal 126 residues of the adult skeletal muscle sodium channel were synthesized and tested by radioimmunoassay against each antibody. Both monoclonals bound only to a peptide comprising residues 1–30 (I1–30). A nested set of peptides within this region was then synthesized and used to compete for antibody binding to II1–30. L/D3 binding was quantitatively inhibited by oligopeptides 1–30, 7–30, 13–30, and 19–30 but not 25–30, while binding of A/B2 was blocked only by the intact I1–30 peptide. This data implies that the epitope for L/D3 lies within residues 19–25 while the epitope for A/B2 is contained within residues 1–6. These tentative epitope localizations were confirmed using both proteolytic cleavage of I1–30 and immunoreactivity of a peptide corresponding to residues 1–12 with A/B2 but not L/D3. Therefore, epitopes for each monoclonal antibody are present in the SkM-1 sequence and are in close proximity in the amino-terminus of the protein. Their characteristic immunocytochemical labeling patterns may reflect differing accessibility of the epitopes in various membrane environments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231814
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  • 7
    Electronic Resource
    Electronic Resource
    Agenesis of dorsal pancreas in a patient with weight loss and diabetes mellitus (1994)
    Springer
    Digestive diseases and sciences 39 (1994), S. 1708-1713 
    Details
    ISSN: 1573-2568
    Keywords: pancreatic anomalies ; diabetes mellitus ; pancreatic exocrine insufficiency ; endoscopic retrograde cholangiopancreatography ; computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02087781
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  • 8
    Electronic Resource
    Electronic Resource
    Pneumatic dilatation or esophagomyotomy treatment for idiopathic achalasia: Clinical outcomes and cost analysis (1993)
    Springer
    Digestive diseases and sciences 38 (1993), S. 75-85 
    Details
    ISSN: 1573-2568
    Keywords: esophagus ; esophageal motility disorders ; esophagomyotomy ; cost analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The choice between pneumatic dilatation and surgical esophagomyotomy as the initial treatment for achalasia is controversial. The aims of this study were to determine the long term clinical outcome and costs of treating achalasia initially with pneumatic dilatation as compared to esophagomyotomy. Of 123 patients undergoing an initial pneumatic dilatation for achalasia at our institution from 1976 to 1986, 71 (58%) received no further treatment for achalasia during a mean follow up of 4.7±2.8 years. Only 15 of these 123 patients (12%) eventually underwent surgical esophagomyotomy, (two for perforation during pneumatic dilatation, 13 for persistent or recurrent symptoms). The degree of dysphagia at follow up was improved to a similar degree in patients treated with an initial pneumatic dilatation as compared to patients treated with an initial esophagomyotomy. Patients with age≥45, years at time of initial pneumatic dilatation had fewer subsequent treatments for persistent or recurrent symptoms and had less dysphagia on follow up as compared to patients 〈45 years. Subsequent pneumatic dilatations to treat persistent or recurrent symptoms were less beneficial than an initial pneumatic dilation. The cost of esophagomyotomy was 5 times greater than the cost of pneumatic dilatation. When costs were analyzed to include subsequent treatments of symptomatic patients, the total expectant costs of treating with an initial esophagomyotomy remained 2.4 times greater than treating with an initial pneumatic dilatation. This study suggests that an initial pneumatic dilatation will be the only treatment needed for the majority of patients with achalasia. A treatment regimen starting with penumatic dilatation has less overall costs than starting with esophagomyotomy. For each subsequent pneumatic dilatation, however, the clinical benefit leans toward, surgery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01296777
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  • 9
    Electronic Resource
    Electronic Resource
    Complications during pneumatic dilation for achalasia or diffuse esophageal spasm (1993)
    Springer
    Digestive diseases and sciences 38 (1993), S. 1893-1904 
    Details
    ISSN: 1573-2568
    Keywords: esophageal perforation ; esophagomyotomy ; esophageal motility disorders
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A retrospective cohort study was performed to assess risk factors, early clinical characteristics, and outcome of complications in patients undergoing pneumatic dilation. Of 178 patients with achalasia or diffuse esophageal spasm who underwent 236 dilations with a Browne-McHardy dilator, 16 patients experienced a complication (9.0%). Nine major complications developed: perforations (4), hematemesis (2), fever (2), and angina (1). A prior pneumatic dilation and use of inflation pressure ≥11 PSI were independent risk factors by multivariate analysis for developing a complication. An esophagram immediately following the dilation identified three of the four perforations. Three postdilation findings were identified as indicators of patients with an increased risk of having developed a perforation: blood on the dilator, tachycardia, and prolonged chest pain lasting 〉4 hr after dilation. In all patients incurring a major complication, one of the three indicators, or the complication itself was recognized within 5 hr of dilation. All patients with complications, including the four with perforation who received prompt surgical repair and esophagomyotomy, recovered uneventfully. The symptomatic relief of dysphagia in patients with perforation undergoing emergent surgical repair and esophagomyotomy was similar to patients undergoing elective esophagomyotomy. Conclusions: (1) Pneumatic dilation is a safe treatment of achalasia, with a 1.7% risk of perforation. (2) The risk of developing a complication is increased by having had a previous pneumatic dilation or by use of inflation pressures ≥11 psi. (3) All patients with a major complication were identified within 5 hr after dilation. (4) Complications following pneumatic dilation, if recognized and treated promptly, were not associated with adverse, long-term sequelae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01296115
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  • 10
    Electronic Resource
    Electronic Resource
    Nonoperative management of esophageal strictures following esophagomyotomy for achalasia (1994)
    Springer
    Digestive diseases and sciences 39 (1994), S. 2102-2108 
    Details
    ISSN: 1573-2568
    Keywords: esophageal stricture ; achalasia ; dilation ; reflux esophagitis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The optimal management of reflux-induced esophageal strictures that occur after esophagomytomy for achalasia is uncertain. This paper presents our experience with the nonsurgical treatment of postesophagomyotomy strictures in achalasia patients using endoscopic dilation and gastric acid suppression. Six patients with achalasia who had undergone prior esophagomyotomy subsequently developed recurrent dysphagia and were found to have an esophageal stricture. Esophagrams typically showed a markedly dilated esophagus with a narrowed, sharply angulated gastroesophageal junction. Esophageal manometry confirmed esophageal aperistalsis and, when measured, the LES pressure was〈5 mm Hg. Endoscopy showed esophageal inflammation and a fixed stricture at the gastroesophageal junction. Strictures were dilated under direct visualization using through-the-scope balloon dilators. Patients began gastric acid suppressive treatment at the same time. Five patients who remained symptomatic underwent repeat endoscopy, which demonstrated improvement in esophagitis. Dilation was then repeated with a larger balloon dilator. Over a mean follow-up period of 3.8 years, the average number of repeat dilations per patient was 3.6 (range: 0–12). All patients had symptomatic improvement and weight gain. No patient required surgery. We conclude that esophageal strictures after esophagomyotomy for achalasia can be safely treated using endoscopic dilation and gastric acid suppression, thus avoiding the need for reoperation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02090357
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