Asian tigers and the Chinese dragon: Competition and collaboration between sentinels of pandemics from SARS to COVID-19

This article compares the management of COVID-19 in different Asian states—China, Hong Kong, Singapore, Taiwan, South Korea, Japan, and Vietnam—after their reactions to the SARS crisis in 2003. It uses animal metaphors and the concept of sentinel territory to describe the way these states have prepared for the next pandemic crisis in a mix of competition and collaboration that produces solidarity.     

Passive components in the subscriber loop

The status of passive optical components for optical fiber subscriber loop systems is reviewed in the context of the most often discussed architectures. These architectures and the passive component types and functions are described. It is shown how the components are meeting the key functional requirements of interconnection, furcation, and filtration. A logic flow to the evolution of the architecture which is based on the expected development of the passive components is indicated     

Heat transfer from metallic filaments (whiskers) into helium under overcritical pressure for temperatures between 3.7 and 7.2 K

The heat transfer coefficient α, near the critical temperature, T_cO, was determined for several whiskers from the In-Pb alloy system. For this purpose the hysteresis of the voltage-temperature (V-T_B) transition curves at fixed currents, I, and of the V-I characteristics at fixed helium bath temperature, T_B, was determined. The advantage of using measurements made with whiskers is that there is no heat transfer to a substrate and negligible heat transfer to the contracts. The only heat transfer is that to the surrounding helium.     

Computer-generated profiles of the anal canal in patients with anal fissure

PURPOSE: The pathophysiology of anal fissure remains poorly understood. This study examines manometric findings in patients with anal fissure with use of a computer-assisted system, which helps to standardize manometric performance as well as generating longitudinal and cross-sectional profiles of the anal canal. METHODS: Water-perfused, eight-channel, computer-assisted manometry was performed on 12 patients with chronic anal fissure and compared with 12 age-matched and sex-matched controls. RESULTS: Mean maximum average resting pressure (MARP) was 120.5 mmHg in patients and 82.6 mmHg in controls (P = 0.0005). Pain was felt during manometry in six patients. In these patients, MARP was 123.2 mmHg, and, in the other six patients, MARP was 117.8 mmHg. Sphincter length was 4.72 cm, and the high pressure zone or that part of the sphincter with pressure more than 50 percent of MARP) was 2.78 cm in length. The high pressure zone/sphincter length ratio was 58 percent compared with 48 percent in controls. Longitudinal profile was bell shaped. Elevated pressures were not confined to the site of the fissure. Cross-sectional analysis showed higher anterior pressures in the distal sphincter. Ultraslow waves were seen in as many as 91 percent of patients and 73 percent of controls. However, ultraslow wave amplitude was 31 mmHg in patients and 15 mmHg in controls (P = 0.03). The rectoanal reflex was normal; overshoot was not seen. CONCLUSIONS: The primary abnormality in fissure is persistent hypertonia affecting the entire internal sphincter, unrelated to pain. Cross-sectional pressure profiles may explain the predilection of fissures to occur in the posterior midline; other factors must prevent chronic fissures from healing.     

Sequestration of the lung arising from the circumflex coronary artery

The patterns of macroscopic growth of 20 first generation human tumor xenografts (16 renal cell carcinomas and 4 squamous cell carcinomas of the head and neck region) were studied with the recursion formula of the Gompertz function. This method enables the characterization of each tumor growth pattern by two parameters: (i) parameter a, which correlates with the starting growth rate of the tumor and (ii) parameter b, which is a measure of the intensity of growth deceleration as a function of tumor growth. A statistically significant prediction of the establishment of a xeno-transplantation line after serial subpassaging (in 9/20 tumors) according to the characteristics of first passage growth curves (p<0. 01) is reported. Especially parameter b, the value of the growth deceleration, highly correlates with serial growth: tumors showing less growth deceleration (higher b-values) during first passage more frequently develop into transplantation lines. On the contrary line development could not be predicted on the basis of the a-values of the first passage growth curves alone (p=0.137). This observation adds to the accumulating evidence, that the process of tumor growth deceleration is a pivotal parameter of tumor biology. Moreover, the present evaluation substantially reduces the time needed to assay serial growth of tumor xenografts for prognostic purposes making this assay potentially more attractive for clinical use.     

Segmentation and endogenous entry under consumer uncertainty of novel technologies

The paper presents a model of new product marketing when consumers are unable to provide perfect information on their preferences. Given the information available, firms have to decide their new product introduction strategy. Two situations are examined: a monopolist deciding on how many segments to enter, and a duopoly facing a single market segment in which each firm must decide to enter first or second. The monopolist strategy turns out to be either entering many segments when the uncertainty is low or a market niche when it is high. For the duopoly situation, a firm with limited resources wants to enter first whereas a firm with large resources wants to go second. This outcome is an endogenous equilibrium of the model.     

Crack detection by resonant frequency measurements

The resonant frequency of 304 stainless steel specimens with a center-drilled hole has been measured as a function of fatigue cycles during crack initiation and propagation. Simultaneous measurements of crack lengths by scanning electron microscopy yield the resonant frequencyvs crack length. The change of resonant frequency is equivalent to the change of an effective elastic modulus. Analytical results for a “spring” model to predict the change in effective modulus due to the presence of cracks have been compared with results derived from resonant tests. In the model, the load transfer across the plane of the crack is represented by a distribution of springs of stiffness that depends on the crack length. Good agreement is observed between theory and experiment for cracks up to 500-μm long. The model may be used to obtain the crack length from resonance measurements. Formerly with the Materials Science and Engineering Department, Northwestern University, Evanston, IL 60208,     

Simultaneous measurement of pulmonary venous flow by intravascular catheter Doppler velocimetry and transesophageal Doppler echocardiography: relation to left atrial pressure and left atrial and left ventricular function

OBJECTIVES: The aim of our study was to compare measurements of pulmonary venous flow velocity obtained either by transesophageal Doppler echocardiography or by intravascular catheter Doppler velocimetry. Furthermore, the relation among pulmonary venous flow velocity, left atrial compliance and left atrial pressure was evaluated. BACKGROUND: Data about the relation between left atrial pressure and pulmonary venous flow velocity are controversial. METHODS: A total of 32 patients undergoing elective open heart surgery for coronary artery bypass grafting were included prospectively in the study. Pulmonary venous flow velocity (Doppler catheter) and left atrial pressure (microtip pressure transducer) were recorded simultaneously with recordings of pulmonary venous flow velocity obtained by transesophageal Doppler echocardiography. RESULTS: Agreement between Doppler catheter and Doppler echocardiographic measurements of pulmonary venous flow velocity (n = 18 patients) was analyzed using the Bland-Altmann technique. The 95% limits of agreement were -0.16 to +0.11 m/s for systolic peak velocity, -0.14 to +0.09 m/s for diastolic peak velocity and -0.12 to +0.10 m/s for atrial peak velocity. The closest agreement between both methods was found for the ratio of systolic to diastolic peak velocity, the ratio of systolic to diastolic flow duration and the time from Q deflection on the electrocardiogram to maximal flow velocity. Mean left atrial pressure was strongly correlated with the ratio of systolic to diastolic peak velocity (r = -0.829), systolic velocity-time integral (r = -0.653), time to maximal flow velocity (r = 0.844) and the ratio of systolic to diastolic flow duration (r = -0.556). The ratio of systolic to diastolic peak velocity and the time to maximal flow velocity were identified as strong independent predictors of mean left atrial pressure. Left atrial compliance was not found to be an independent predictor of mean left atrial pressure. CONCLUSIONS: Flow velocity in the left upper pulmonary vein can be reliably recorded by transesophageal pulsed wave Doppler echocardiography. Our data reveal further evidence that mean left atrial pressure can be estimated by the pattern of pulmonary venous flow velocity.