The Notch ligand, Jagged-1, influences the development of primitive hematopoietic precursor cells

We examined the expression of two members of the Notch family, Notch-1 and Notch-2, and one Notch ligand, Jagged-1, in hematopoietic cells. Both Notch-1 and Notch-2 were detected in murine marrow precursors (Lin-Sca-1+c-kit+). The Notch ligand, Jagged-1, was not detected in whole marrow or in precursors. However, Jagged-1 was seen in cultured primary murine fetal liver stroma, cultured primary murine bone marrow stroma, and in stromal cell lines. These results indicate a potential role for Notch-Notch ligand interactions in hematopoiesis. To further test this possibility, the effect of Jagged-1 on murine marrow precursor cells was assessed by coculturing sorted precursor cells (Lin-Sca-1+c-kit+) with a 3T3 cell layer that expressed human Jagged-1 or by incubating sorted precursors with beads coated with the purified extracellular domain of human Jagged-1 (Jagged-1(ext)). We found that Jagged-1, presented both on the cell surface and on beads, promoted a twofold to threefold increase in the formation of primitive precursor cell populations. These results suggest a potential use for Notch ligands in expanding precursor cell populations in vitro.     

Standard biopsy forceps versus large-capacity forceps with and without needle

Endoscopic biopsy forceps vary in size and design. The purpose of this prospective randomized study was to compare the quality and quantity of gastric tissue obtained by needle and non-needle versions of standard biopsy forceps and newly designed large capacity forceps. Fifty consecutive patients who underwent endoscopy with gastric biopsy forceps were enrolled in the study. There was no significant difference in the presence of crush artifact between the two forceps, both with and without the presence of a needle. Both needle and non-needle versions of the large capacity biopsy forceps were found to obtain significantly larger sized specimens (p = 0.02) than needle and non-needle versions of the standard biopsy forceps. Overall, there was no significant difference in the depth of specimen obtained when comparing the large capacity forceps to standard forceps. Needle versions of each forceps were found to obtain significantly deeper biopsies than non-needle versions of each forceps. In conclusion, our study found that large capacity forceps obtained larger specimens than standard biopsy forceps. Further clinical trials with a larger study population need to be undertaken to determine the impact of these findings on the determination of diagnoses.     

Analysis And Processing of LANDSAT-4 Sensor Data Using Advanced Image Processing Techniques And Technologies

Techniques have been developed or improved to calibrate, repair, geometrically correct, and extract information from Landsat-4 satellite data. Statistical techniques to correct data radiometry have been evaluated and have minimized striping and banding. It is shown that unless these statistical techniques are used, striping will result even with perfect calibration parameters. Algorithms have been developed to replace data from failed detectors and to reduce coherent noise. The Landsat-4 data have been geometrically corrected to conform to a 1:100 000 map reference to an accuracy of about 41 m. The data were then recorded onto film, and image products produced that can serve as low-cost accurate map products. To decrease the dimensionality of the Landsat-4 data, principal component transformation of the data to four significant new bands was performed, and the results compared with latest available land use maps. The transformation is useful for land use analysis and in delineating vegetation anomalies which appear to reflect areas underlain by altered serpentinite. A range of image processing systems have been used to process the satellite data, including general purpose, special purpose, and personal computers. These systems are described, along with their processing performance. Index Terms-Digital Image Processing, Thematic Mapper, Multispectral Scanner, Calibration, Geometric Correction, Mapping, Digital Terrain, Enhancement, Noise Removal, Personal Computer, Entropy, Principal Components, Banding, Striping, Information Extraction, Geology, Land Use.     

Potential Practical Applications of Basic Research in Molecular Dynamics

The chemical technology of the future will require a deeper knowledge of fundamental molecular-dynamical processes. It will no longer suffice to be able to systematize (and even calculate) static properties of simple molecules in equilibrium or to produce tables of Arrhenius kinetic parameters characterizing the rate constants of a host of elementary chemical reactions. In order to make significant gains, in the sense of “breakthrough technology”, an intimate knowledge of basic molecular dynamical behavior will be needed. Such insight is derivable from a new class of experiments at the atomic and molecular level and from new theoretical-computational approaches to molecular-dynamical problems. To illustrate these new requirements, and the potential practical applications of an improved understanding at the basic level, examples are presented in the areas of combustion and atmospheric pollution, atmospheric and ionospheric chemistry, synthetic applications of selective excitation, lasers in chemistry and chemical-to-radiation energy conversion.     

Managing telecommunications networks

The authors suggest that one must view the network itself as the customer's database, and make sure it is self-diagnosing, self-healing, and intelligent. The perspective that the network is the database means moving away from the feeling that no trouble means total health, towards more preemptive maintenance. With fiber, capacity as a limiting factor is no longer an issue; the creative work will be in developing network capabilities. Universities need to accept the challenge of developing the theory of software stability. A crazy quilt of multiple equipment vendors cannot produce an integrated, problem-solving network. But if a network is self-diagnosing, self-healing, and intelligent, the available staff can focus on the customer and seize opportunities to introduce new services     

Laparoscopic evaluation of liver disease in chronic renal failure prior to renal transplantation

It is not rare that controversial indications about the presence or the expression level of multidrug-resistant (MDR) proteins come out from different laboratories upon examination of identical tumor specimens. Distinct aspects, including the use of weakly discriminating monoclonal antibodies (MAbs) and/or unsuitable techniques and procedures, contribute in generating differences in the MDR phenotype evaluation of cancer cells. In this regard we describe here an innovative immunohistochemical approach for the determination of P-glycoprotein expression in cells and tissues. The method is based on the ability of phage-displayed peptides to mimic antibody epitopes. For this purpose we utilized the phage clone #55, which was affinity-purified from a phage-displayed random-peptide library using the MAb MM4.17 (specific for MDR1-P-glycoprotein) as previously described. This clone has been chosen since it clearly and undoubtedly reacts with its cognate MAb, as was determined by ELISA and dot blot tests. Inhibition of the MAb MM4.17 binding to MDR1-P-glycoprotein-expressing cells could be performed by adding a calibrated concentration of phage clone #55 particles, which mimic MDR1-P-glycoprotein antigen. This methodology can eliminate misleading interpretations concerning the presence and expression level of MDR1-P-glycoprotein and might well contribute in routine clinical determinations of MDR in tumor specimens, thus contributing to our understanding of the basis of the mechanisms of tumor cell resistance to drugs.     

Hydrogen etching for semiconductor materials in plasma doping experiments

The etching effects of hydrogen plasma for semiconductor materials including single crystalline silicon, polycrystalline silicon, silicon dioxide, and aluminum in plasma immersion ion implantation (PHI) doping experiments have been investigated. Etching can alter device structure and affect implant profile and dose. The effects of varying different PIII process parameters such as pulse potential, pulse repetition frequency, and substrate temperature are presented. The experimental data show that the spontaneous etching by hydrogen radicals enhanced by ion bombardment is responsible for the etching phenomena that occurs at the material surface. A model is used to calculate the retained implant dose and impurity profile when the etching effect is considered.     

The adequacy of medical school education in musculoskeletal medicine

A basic familiarity with musculoskeletal disorders is essential for all medical school graduates. The purpose of the current study was to test a group of recent medical school graduates on basic topics in musculoskeletal medicine in order to assess the adequacy of their preparation in this area. A basic-competency examination in musculoskeletal medicine was developed and validated. The examination was sent to all 157 chairpersons of orthopaedic residency programs in the United States, who were asked to rate each question for importance and to suggest a passing score. To assess the criterion validity, the examination was administered to eight chief residents in orthopaedic surgery. The study population comprised all eighty-five residents who were in their first postgraduate year at our institution; the examination was administered on their first day of residency. One hundred and twenty-four (81 per cent) of the 154 orthopaedic residency-program chairpersons who received the survey responded to it. The chairpersons rated twenty-four of the twenty-five questions as at least important. The mean passing score (and standard deviation) that they recommended for the assessment of basic competency was 73.1 +/- 6.8 per cent. The mean score for the eight orthopaedic chief residents was 98.5 +/- 1.07 per cent, and that for the eighty-five residents in their first postgraduate year was 59.6 +/- 12 per cent. Seventy (82 per cent) of the eighty-five residents failed to demonstrate basic competency on the examination according to the chairpersons' criterion. The residents who had taken an elective course in orthopaedic surgery in medical school scored higher on the examination (mean score, 68.4 per cent) than did those who had taken only a required course in orthopaedic surgery (mean score, 57.9 per cent) and those who had taken no rotation in orthopaedic surgery (mean score, 55.9 per cent) (p = 0.005 and p = 0.001, respectively). In summary, seventy (82 per cent) of eighty-five medical school graduates failed a valid musculoskeletal competency examination. We therefore believe that medical school preparation in musculoskeletal medicine is inadequate.