Differential requirements for ZAP-70 in TCR signaling and T cell development

The Syk/ZAP-70 family of protein tyrosine kinases is indispensable for normal lymphoid development. Syk is necessary for the development of B cells and epithelial gammadelta T cells, whereas ZAP-70 is essential for the normal development of T cells and TCR signaling. In this study, we show that although development of the alphabeta lineage was arrested in the thymus, CD3-positive T cells, primarily of the gammadelta lineage, were present in the lymph nodes of mice lacking ZAP-70. Moreover, in the absence of ZAP-70, dendritic epidermal T cells were fewer in number and of abnormal morphology, and intestinal intraepithelial lymphocytes, normally containing a large proportion of gammadelta T cells, were markedly reduced. These data suggest that gammadelta T cells show a variable dependence upon ZAP-70 for their development. Biochemical analyses of thymocytes revealed a lack of basal zeta-chain tyrosine phosphorylation. However, several other substrates were inducibly tyrosine phosphorylated following TCR stimulation. Thus, TCR-mediated signaling in ZAP-70-deficient thymocytes is only partially impaired. These studies suggest that Syk compensates only partially for the loss of ZAP-70, and that there is an absolute requirement of ZAP-70 for alphabeta T cells and epithelial gammadelta T cells, but not for some gammadelta T cells in peripheral lymphoid tissues.     

Rapid software development through team collocation

In a field study conducted at a leading Fortune 100 company, we examined how having development teams reside in their own large room (an arrangement called radical collocation) affected system development. The collocated projects had significantly higher productivity and shorter schedules than both the industry benchmarks and the performance of past similar projects within the firm. The teams reported high satisfaction about their process, and both customers and project sponsors were similarly highly satisfied. The analysis of questionnaire, interview and observational data from these teams showed that being "at hand," i.e. both visible and available, helped them to coordinate their work better and learn from each other. Radical collocation seems to be one of the factors leading to high productivity in these teams.     

Measuring e-business performance: Towards a revised balanced scorecard approach

The balanced scorecard (BSC) is a management system that enables executives and managers to map their strategic objectives onto a set of performance measures in four inter-related areas, known as the financial, customer, learning and growth, and the internal process perspectives. Based on research into leading and lagging e-business companies and their measurement practices, this paper introduces an approach to modifying the balanced scorecard, applicable to the management of e-business units in which the customer perspective of the traditional balanced score card is supplemented by the incorporation of four additional perspectives (brand, service, market and technology) that have been found to be critical to the development and execution of e-business strategies. This approach facilitates a clearer understanding of the customer perspective, which consequently benefits the process of selecting the goals and measures associated with the other three perspectives, improving the quality of the overall decision-making and managerial processes as a whole.     

Genetic divergence in cellular resistance to heat shock in cattle: differences between breeds developed in temperate versus hot climates in responses of preimplantation embryos,reproductive tract tissues and lymphocytes to increased culture temperatures

The detrimental effects of heat stress on fertility in cattle are less pronounced in heat-tolerant breeds. Although these genetic differences reflect differences in thermoregulation, cells from heat-tolerant breeds are less adversely compromised by increased temperature (that is, heat shock) than cells from heat-sensitive breeds. Experiments were performed to test the hypothesis that cells and tissues from two thermotolerant breeds (Brahman and Senepol) are better able to survive and function after exposure to increased temperature than cells and tissues from two thermosensitive breeds (Holstein and Angus). Exposure of embryos at>eight-cell stage at day 5 after insemination to heat shock of 41.0 degrees C for 6 h decreased development to the blastocyst stage and the number of cells per embryo. However, the deleterious effect of heat shock on blastocyst formation and the number of cells per embryo was less pronounced for Brahman than for Holstein and Angus breeds. Embryos from Senepol cows had very low development and it was not possible to determine heat shock effects in this breed. In contrast to the sensitivity of embryos to heat shock, there was no effect of a 41.0 degrees C heat shock on [(3)H]leucine incorporation into proteins secreted by oviductal or endometrial explants. Lymphocytes from Brahman and Senepol cows were more resistant to heat-induced apoptosis than lymphocytes from other breeds. Heat shock reduced lymphocyte glutathione content but the magnitude of the decrease was not affected by breed. In conclusion, embryos from Brahman cows are more resistant to heat shock than embryos from Holstein or Angus cows. Genetic differences are also present in thermotolerance for apoptosis response in lymphocytes, with Brahman and Senepol cattle being more resistant to heat shock than Angus and Holstein breeds. It is likely that the evolutionary forces that led to the Brahman and Senepol breeds being adapted to hot climates resulted in the selection of genes controlling resistance to cellular heat shock.     

Scanning tunneling microscopy with chemically modified gold tips: in situ reestablishment of chemical contrast

A method was developed for the reestablishment of chemical contrast in STM images obtained with chemically modified gold tips. Such tips display selective chemical contrast, which allows the selective imaging of specific species on the sample surface. Chemically modified STM tips can be fabricated by forming a self-assembled monolayer (SAM) on an electrochemically etched gold tip. One difficulty with this method thus far has been the relatively short lifetime of SAM-treated tips. The method described here utilizes the brief application of a high bias voltage between the sample and the tip to cause SAM molecules to reoccupy the tip apex, thereby allowing the tips to display selective chemical contrast in imaging. These treatments consist of applying a +1.9-V sample bias for 0.5-10 min under tunneling conditions. The usable lifetime of SAM-modified tips could be increased by more than 2 orders of magnitude, from hours to at least a month, dramatically increasing the efficiency of using SAM-modified gold tips. SAM molecules can also be removed from the tip apex by application of a negative sample bias (-2.0 V for 0.5-10 min) making it possible to alternate between conventional STM images and STM images with chemically enhanced contrasts.     

Coupling bulge testing and nanoindention to characterize materials properties of bulk micromachined structures

Nanoindentation and the continuous stiffness method was used to obtain the elastic modulus of Pb(Zr_xTi_1–x)O₃ (X:1–XPZT) thin films that can be utilized in high aspect ratio structures. PZT films were deposited onto bulk micromachined silicon wafers by sol–gel deposition and two annealing treatments. Conventional annealing produced films that had an elastic modulus of 80 GPa for both the 52:48 and 40:60 PZT, while a 52:48 PZT deposited using rapid thermal annealing demonstrated a modulus of 70 GPa. These moduli allowed accurate stress measurements of both the composite membranes by bulge testing and also the individual PZT layers by X-ray diffraction. The residual tensile stress in the PZT film ranged from 190 to 400 MPa. Residual stresses were shown to affect both the strain to failure and the resonance frequency of the membrane generators. The applied strain to failure decreased with increasing residual stress. A tungsten underlayer was added to reduce the composite residual stress and increase the compliance, lowering the resonant frequency from 23 to 18 kHz.The authors gratefully acknowledge the support from the U.S. Department of Energy through Contract DE-AC04-94AL85000, DARPA MTOs MicroPower Generation Program, the US Army SMDC contract #DASG60-02-C0001, and the Army Research Laboratories. Additional financial support was provided by the National Science Foundation DMI under the XYZ on a chip program grant #9980837. The authors would also like to thank M. Thompson and R. Polcawich for fabrication of at the ARL of RTA films, K. Shafer and R. Gifford of WSU for experimental assistance, and project supervision by C.D. Richards and R.F. Richards. Characterization by D. McCready and J. Young was performed at the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energys Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.     

Optical and MRI multifunctional nanoprobe for targeting gliomas

A multifunctional nanoprobe capable of targeting glioma cells, detectable by both magnetic resonance imaging and fluorescence microscopy, was developed. The nanoprobe was synthesized by coating iron oxide nanoparticles with covalently bound bifunctional poly(ethylene glycol) (PEG) polymer, which were subsequently functionalized with chlorotoxin and the near-infrared fluorescing molecule Cy5.5. Both MR imaging and fluorescence microscopy showed significant preferential uptake of the nanoparticle conjugates by glioma cells. Such a nanoprobe could potentially be used to image resections of glioma brain tumors in real time and to correlate preoperative diagnostic images with intraoperative pathology at cellular-level resolution.     

The effect of different grain diets on fecal shedding of Escherichia coli O157:H7 by steers

Three groups of six yearling steers (three rumen fistulated plus three nonfistulated) fed one of three different grain diets (85% cracked corn, 15% whole cottonseed and 70% barley, or 85% barley) were inoculated with 10(10) CFU of Escherichia coli O157:H7 strain 3081, and the presence of the inoculated strain was followed in the rumen fluid and feces for a 10-week period. E. coli O157:H7 was rapidly eliminated from the rumen of the animals on all three diets but persisted in the feces of some animals up to 67 days after inoculation, suggesting that the bovine hindgut is the site of E. coli O157:H7 persistence. A significant difference existed in the levels of E. coli O157:H7 shed by the animals among diets on days 5, 7, 49, and 63 after inoculation (P < 0.05). No significant difference was found between the levels shed among diets on days 9 through 42 and on day 67 (P > 0.05). The number of animals that were culture positive for E. coli O157:H7 strain 3081 during the 10-week period was significantly higher for the barley fed group (72 of 114 samplings) as opposed to the corn fed group (44 of 114 samplings) (P < 0.005) and the cottonseed and barley fed group (57 of 114 samplings) (P < 0.05). The fecal pH of the animals fed the corn diet was significantly lower (P < 0.05) than the fecal pH of the animals fed the cottonseed and barley and barley diets, likely resulting in a less suitable environment for E. coli O157:H7 in the hindgut of the corn fed animals. E. coli O157:H7 strain 3081 was present in 3 of 30 (corn, 1 of 10; cottonseed, 1 of 10; barley, 1 of 10) animal drinking water samples, 3 of 30 (corn, 1 of 10; cottonseed, 0 of 10; barley, 2 of 10) water trough biofilm swabs, 5 of 30 (corn, 0 of 10; cottonseed, 2 of 10; barley, 3 of 10) feed samples, and 30 of 30 manure samples taken from the pens during the entire experimental period. Mouth swabs of the steers were also culture positive for E. coli O157:H7 strain 3081 in 30 of 180 samples (corn, 7 of 60; cottonseed, 4 of 60; barley, 19 of 60) taken during the 10-week period. Minimizing environmental dissemination of E. coli O157:H7 in conjunction with diet modification may reduce numbers of E. coli O157:H7-positive cattle.     

Fusion of body surface potential and body surface Laplacian signals for electrocardiographic imaging

Various approaches to the solution to the inverse problem of electrocardiography have been proposed over the years. Recently, the use of inverse algorithms using measured body surface Laplacians has been proposed, and in various studies this technique has been shown to outperform the traditional use of body surface potentials in certain model problems. In this paper, we compare the use of body surface potentials and body surface Laplacians on two model problems with different assumed cardiac sources. For the spherical cap model problems with an anterior source, the epicardial estimates using body surface potentials had smaller average relative errors than when body surface Laplacians were used. For the spherical cap model problems with a posterior source, the epicardial estimates using body surface potential or body surface Laplacian sensors generally produced similar relative errors. For the radial dipole model, the epicardial estimates using body surface Laplacians had smaller errors than when body surface potentials were used. We introduce a fusion algorithm that combines the different types of signals and generally produces a good estimate for both model problems.     

Narrative discourse in children with early focal brain injury

Children with early brain damage, unlike adult stroke victims, often go on to develop nearly normal language. However, the route and extent of their linguistic development are still unclear, as is the relationship between lesion site and patterns of delay and recovery. Here we address these questions by examining narratives from children with early brain damage. Thirty children (ages 3:7-10:10) with pre- or perinatal unilateral focal brain damage and their matched controls participated in a storytelling task. Analyses focused on linguistic proficiency and narrative competence. Overall, children with brain damage scored significantly lower than their age-matched controls on both linguistic (morphological and syntactic) indices and those targeting broader narrative qualities. Rather than indicating that children with brain damage fully catch up, these data suggest that deficits in linguistic abilities reassert themselves as children face new linguistic challenges. Interestingly, after age 5, site of lesion does not appear to be a significant factor and the delays we have witnessed do not map onto the lesion profiles observed in adults with analogous brain injuries.