Expression of human muscarinic cholinergic receptors in tobacco

The T lymphocyte beta 2-adrenergic receptor (beta 2AR) density and function were compared in 15 patients suffering acute myocardial infarction and 10 patients with stable coronary artery disease (CAD). Density was determined using radioligand binding with 125IPIN, and function by in vitro cyclic adenosine 3',5'-monophosphate (cAMP) production. In patients suffering acute myocardial infarction, T lymphocyte beta 2AR density (823.8 +/- 480 sites/cell) was slightly but not significantly different from that in patients with stable CAD (629 +/- 301 sites/cell). There was no difference in T lymphocyte cAMP production at baseline (1.11 +/- 0.70 vs 1.04 +/- 0.49 pM/10(6) cells) or after isoproterenol stimulation (2.53 +/- 1.63 vs 2.62 +/- 2.05 pM/10(6) cells), respectively. Further study is necessary to determine if beta 2AR numbers on T lymphocytes are significantly increased after acute myocardial infarction.     

Independently addressable VCSEL arrays on 3-μm pitch

We present an exceedingly dense linear vertical-cavity surface-emitting laser (VCSEL) array with independently addressable elements on a staggered 3-μm pitch. Our devices utilize an all-epitaxial structure and operate at a wavelength of 813 mm with threshold currents below 400 μA. The high-packing density is enabled by combining transparent contact technology with a planar laterally oxidized device architecture. The array exhibits low interelement thermal crosstalk and has electrical resistances of 3 MΩ between adjacent array elements     

Model for Construction Budget Performance—Neural Network Approach

A neural network approach is used to identify the key management factors that affect budget performance in a project. Field data of project performance has been used to build the budget performance model. This approach allows the model to be built even if the functional interrelationships between input factors and output performance cannot be clearly defined. Altogether eight key determining factors were identified covering areas related to the project manager, project team, and planning and control efforts, namely: number of organizational levels between project manager and craftsmen, project manager experience on similar technical scope, detailed design complete at start of construction, constructability program, project team turnover rate, frequency of control meetings during construction, frequency of budget updates, and control system budget. The model is able to give good predictions even with previously unseen data and incomplete information on the key factors. The model can be used to evaluate various management strategies and thus resources can be effectively deployed to strengthen these aspects of project management.     

Entropy production analysis and experimental confirmation of absorption systems

Absorption chillers, heat pumps and heat transformers exploit thermal power input to satisfy a variety of refrigeration and heating applications, as well as to boost the temperature of low-grade heat. Can one arrive at accurate predictions of system performance with a simple analytic irreversible thermodynamic model? In capturing the essential physics of the problem, that model would be required to provide a predictive and diagnostic tool and to permit determination of optimal absorption system operating conditions. We derive such a model and check its validity against experimental data and computer simulation results from a variety of commercial absorption units. We reinforce the observation that commercial units appear to have evolved empirically such that maximum efficiency is realized under design conditions. The failure of a host of previously-published endo-reversible thermodynamic models to account for fundamental qualitative features and accurate predictions of system behavior is documented with computer simulation results and experimental performance data.     

Volumetric analysis of tumor extent in nasopharyngeal carcinoma and correlation with treatment outcome

PURPOSE: To investigate the variability of tumor volume in nasopharyngeal carcinoma using quantitative measurements of tumor bulk derived from computed tomography, and to study the prognostic value of tumor volume in comparison with other variables. METHODS AND MATERIALS: Two hundred ninety patients with newly diagnosed nasopharyngeal carcinoma were included in the study. The primary tumor volume (PTV) and nodal tumor volume (NTV) were obtained by outlining the tumor contour followed by summation of areas in sequential pretreatment computed tomography axial scans. Total tumor volume (TTV) was obtained by adding the PTV and NTV. All patients had radiotherapy as the primary treatment, 67 patients also received cisplatin-based neoadjuvant chemotheraphy. RESULTS: A large variation in tumor volume was observed, especially in advanced stage disease. The median PTV (cc) in Ho's T1, T2, and T3 disease were: 6.9 (range: 0.9-42.7), 18.8 (1.6-127.9), and 52.4 (3.3-166.8). The median TTV (cc) in Ho's stage I to IV disease were: 7.6 (range: 1.3-42.7), 19.8 (3.2-55.7), 40.7 (4.1-222.7), and 51.1 (3.1-274.7). Patients with a large PTV (>60 cc) were associated with significantly poorer local control (5-year local control rate: 56%) and disease-specific survival (5-year survival rate: 53%). In patients with a small PTV (< or =20 cc), there were no significant differences in local control among different T stages. Large NTV (>30 cc) was associated with significantly higher distant failure rate (5-year distant relapse-free survival rate: 54%) and lower disease-specific survival (5-year survival rate: 40%). In multivariate analysis, only PTV was found to be an independent factor in predicting local control. CONCLUSION: A large variation of tumor volume was present in different T stage disease of nasopharyngeal carcinoma, and PTV represents an independent prognostic factor of local control that appears to be more predictive than Ho's T stage classification.     

Relation between chemosensitivity and the ventilatory response to exercise in chronic heart failure

OBJECTIVES: This study sought to establish the chemosensitivity of patients with chronic heart failure. BACKGROUND: The ventilatory response to exercise is often increased in patients with chronic heart failure, as characterized by the steeper regression slope relating minute ventilation to carbon dioxide output. We hypothesized that the sensitivity of chemoreceptors may be reset and may in part mediate the exercise hyperpnea seen in this condition. METHODS: Hypoxic and peripheral hypercapnic chemosensitivity were studied in 38 patients with chronic heart failure (35 men, 3 women; mean [+/-SE] age 60.2 +/- 1.3 years; radionuclide left ventricular ejection fraction 25.7 +/- 2.3%) and 15 healthy control subjects (11 men, 4 women; mean age 54.9 +/- 3.0 years) using transient inhalations of pure nitrogen and single breaths of 13% carbon dioxide, respectively. The change in chemosensitivity during mild exercise (25 W) was assessed in the first 15 patients and all control subjects. Central hypercapnic chemosensitivity was also characterized in 25 patients and 10 control subjects by the rebreathing of 7% carbon dioxide in 93% oxygen. Cardiopulmonary exercise testing was performed in all subjects. RESULTS: Maximal oxygen consumption was 16.6 +/- 0.9 versus 29.7 +/- 2.2 mol/kg per min (p < 0.0001), and the ventilation-carbon dioxide output regression slope was 37.2 +/- 1.5 versus 26.5 +/- 1.4 (p < 0.0001) in patients and control subjects, respectively. Hypoxic and central hypercapnic chemosensitivity were enhanced in patients (0.707 +/- 0.076 vs. 0.293 +/- 0.056 liters/min per % arterial oxygen saturation [SaO2], p = 0.0001 and 3.15 +/- 0.41 vs. 2.02 +/- 0.25 liters/min per mm Hg, p = 0.025, respectively) and correlated significantly with the ventilatory response to exercise. Hypoxic chemosensitivity was augmented during exercise in patients and in control subjects but remained higher in the former (1.530 +/- 0.27 vs. 0.685 +/- 0.12 liters/min per %SaO2, p = 0.01). The peripheral hypercapnic chemosensitivity of patients at rest and during exercise was similar to that in control subjects, consistent with its lesser contribution to overall carbon dioxide chemosensitivity. CONCLUSIONS: Enhanced hypoxic and central hypercapnic chemosensitivity may play a role in mediating the increased ventilatory response to exercise in chronic heart failure.     

Reflection-type optical waveguide switch with bow-tie electrode

Based on the total internal reflection and the plasma dispersion effect of SiGe alloy, an intersectional rib optical waveguide switch with bow-tie electrode has been proposed and fabricated for operating wavelengths of 1.3 and 1.55 μm. The thickness of the SiGe layer is 2.6 μm and the width is 9 μm. The branch angle of the switch is 2° and the bow-tie angle is 1.5°. The crosstalks are -19.6 dB for 1.3 μm and -21.8 dB for 1.55 μm. At both wavelengths, the extinction ratio is larger than 38.5 dB and the insertion loss is less than 1.70 dB. The switching time is about 180 ns     

Thermodynamic modeling of an ammonia–water absorption chiller

This article develops a general thermodynamic framework for the modeling of an irreversible absorption chiller at the design point, with application to a single-stage ammonia–water absorption chiller. Component models of the chiller have been assembled so as to quantify the internal entropy production and thermal conductance (UA) in a thermodynamically rigorous formalism, which is in agreement with the simultaneous heat-and-mass transfer processes occurring within the exchangers. Local thermodynamic balance (viz. energy, entropy, and mass balance) and consistency within the components is respected, in addition to the overall thermodynamic balance as determined by the inlet and outlet states of the components. For the absorbers, Colburn-and-Drew mass transfer equations are incorporated to describe the absorption process. Furthermore, the impact of various irreversibilities on the performance of chiller is also evaluated through the use of a general macroscopic equation.